KR20170107740A - Secondary battery and manufacturing method pouch for secondary battery - Google Patents

Abstract

The present invention relates to a secondary battery and a manufacturing method thereof for preventing water penetrating in the horizontal direction from being flowed inside. Also, the secondary battery comprises: an exterior forming an opening part on one side, and storing an electrode assembly forming an electrode lead; a cover arranged to close the opening part; a sealing part sealing a space between the exterior and the cover; and a coating layer coated on the sealing part to make the sealing part watertight.

Description

TECHNICAL FIELD [0001] The present invention relates to a secondary battery and a method of manufacturing a secondary battery,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secondary battery and a method of manufacturing a secondary battery, and more particularly, to a secondary battery and a method of manufacturing a secondary battery for preventing water infiltrating in a horizontal direction from flowing into the inside.

Cells and batteries that generate electrical energy through the physical reaction or chemical reaction of a material and supply power to the outside can not acquire the AC power supplied to the building depending on the living environment surrounded by various electric and electronic devices Or when DC power is needed.

Among such cells, a primary cell and a secondary cell, which are chemical cells using a chemical reaction, are generally used. A primary cell is a consumable cell which is collectively referred to as a dry cell. Also, a secondary battery is a rechargeable battery in which a redox process between a current and a substance is repeatedly manufactured using a material capable of repeatedly repeating. When a reduction reaction is performed on a material by current, the power source is charged, When the power is discharged, the power is discharged. Such charging-discharging is repeatedly performed to generate electricity.

The lithium secondary battery can be divided into a lithium metal battery, a lithium ion battery, and a lithium pouch type battery depending on the electrolyte type.

Here, the method of assembling the lithium pouch-type battery is advantageous in that the electrolyte is solid or gel-shaped, so that even if the battery is broken due to unexpected accident, the electrolyte does not leak out and there is little fear of ignition or explosion, .

In addition, it does not need to use solid metal enclosure, it can be manufactured in various size and shape according to the application, can be made in thickness less than 3mm, can be reduced in weight by 30% or more, mass-produced and large-sized battery can be manufactured .

For this reason, a method of assembling a lithium pouch-type battery is currently commercialized and used in various fields.

Korean Patent Laid-Open Publication No. 10-2001-0104136 discloses a conventional pouch battery.

Such a conventional pouch battery is generally composed of layers of polyethylene terephthalate (PET), nylon, aluminum (Al), and polypropylene (PP), and polypropylene serves as a sealing material.

Here, since the aluminum metal is water-tight, moisture can permeate only in the horizontal direction of the pouch battery.

When moisture permeates in the horizontal direction of the pouch battery, moisture can be diffused into an unspecified region of the polypropylene and permeated into the interior of the pouch battery.

However, in the case of automobile batteries, it is important to maintain the watertightness of the battery because the performance must be maintained for 10 years or more.

Therefore, it is necessary to develop a technique for preventing moisture from penetrating in the horizontal direction of the pouch battery.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a secondary battery and a method for manufacturing a secondary battery that can prevent water from penetrating in the horizontal direction of the secondary battery.

A secondary battery according to the present invention includes an outer case having an opening formed at one side thereof and containing an electrode assembly having an electrode lead formed therein, a lid provided to close the opening, a sealing part sealed to seal between the outer case and the lid, And a coating layer coated on the sealing portion to water-seal the sealing portion.

The coating layer may be an inorganic mixed thin film layer.

The inorganic mixed thin film layer may be formed by mixing at least one of silicon dioxide (SiO 2), aluminum oxide (Al 2 O 3), zinc oxide (ZnO), magnesium fluoride (MgF 2), and titanium dioxide (TiO 2).

The coating layer may be provided at an end of the sealing portion.

The coating layer may be applied to only a part of the sealing portion.

The coating layer may be provided at an end of the sealing portion contacting the electrode lead.

The coating layer may be formed at a corner of the sealing portion.

The method for manufacturing a secondary battery according to the present invention includes a receiving step of receiving the electrode assembly through the opening of the casing, a finishing step of finishing the opening of the casing, a sealing step of sealing the closed part of the casing, Wherein the coating step increases the density of the sealed portion of the casing.

In the finishing step, the opening may be closed by using a lid so that the electrode lead of the electrode assembly is exposed to the outside through the opening of the casing.

In the coating step, a coating liquid may be applied to the sealed portion between the casing and the cover through which the electrode lead passes, thereby forming a coating layer.

According to the present invention, there is an effect that the coating layer is formed on the sealing portion to improve water tightness.

According to the present invention, there is an effect of increasing the density of the sealing portion by forming a coating layer of the inorganic mixed thin film layer on the sealing portion.

According to the present invention, it is possible to selectively form a coating layer only on a part of the sealing part where water tightness is required, thereby reducing manufacturing costs.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing an electrode assembly accommodated in a casing of a secondary battery according to an embodiment of the present invention; FIG.
2 is a perspective view schematically illustrating a secondary battery according to an embodiment of the present invention.
Fig. 3 is a partial cutaway view showing a part of Fig. 2 cut in the "A" direction.
4 is a view showing that the coating layer is applied to only a part of the sealing portion according to another embodiment of the present invention.
5 is a view showing that the coating layer is applied only to the corner of the sealing portion according to another embodiment of the present invention.
6 is a view showing that the coating layer is applied to only one side of the sealing portion according to another embodiment of the present invention.
7 is a view showing that the coating layer is applied to only one side of the sealing portion according to another embodiment of the present invention.
8 is a view showing that the coating layer is applied to only one side of the sealing portion according to another embodiment of the present invention.
9 is a view showing that the coating layer is applied to only one side of the sealing portion according to another embodiment of the present invention.
10 is a flowchart sequentially illustrating a method of manufacturing a secondary battery according to an embodiment of the present invention.

Hereinafter, a secondary battery and a method for manufacturing a secondary battery according to preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and the inventor may appropriately define the concept of the term in order to best describe its invention It should be construed as meaning and concept consistent with the technical idea of the present invention. Therefore, the embodiments described in this specification and the configurations shown in the drawings are only the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

In the drawings, the size of each element or a specific part constituting the element is exaggerated, omitted or schematically shown for convenience and clarity of description. Therefore, the size of each component does not entirely reflect the actual size. In the following description, it is to be understood that the detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

2 is a perspective view schematically illustrating a secondary battery according to an embodiment of the present invention, and FIG. 2 is a perspective view of a secondary battery according to an embodiment of the present invention. Fig. 3 is a partial cutaway view showing a part of Fig. 2 cut in the "A" direction.

1 to 3, a secondary battery according to the present invention includes an opening 110a at one side thereof, a casing 110 for receiving an electrode assembly 3 having an electrode lead 5 formed thereon, A lid 111 provided to close the opening 110a, a sealing part 120 sealed to seal the exterior material 110 and the lid 111, and a sealing part 120 coated on the sealing part 120, And a coating layer 130 for water-tightening the coating layer 120.

The electrode assembly 3 can be manufactured, for example, by laminating a cathode coated with a cathode active material, a cathode coated with a cathode active material, and a separator interposed between the anode and the cathode a plurality of times.

However, the present invention is not limited to this, and the electrode assembly 3 may be manufactured by winding a laminate in which a positive electrode, a separator, and a negative electrode are laminated, in the form of a jelly roll.

The anode may be an aluminum plate, and may include a cathode active material portion coated with the cathode active material, and a cathode uncoated portion not coated with the cathode active material.

The cathode active material may be a lithium-containing transition metal oxide such as LiCoO2, LiNiO2, LiMnO2, LiMnO4, or a lithium chalcogenide compound.

For example, the cathode active material portion may be formed by applying a cathode active material to at least a portion of at least one surface of the aluminum plate, and the remaining portion of the aluminum plate to which the cathode active material is not applied may be anode uncoated.

The negative electrode may be a copper plate, and may include a negative electrode active material portion coated with the negative electrode active material and a negative electrode uncoated portion not coated with the negative electrode active material.

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

The negative electrode active material portion may be formed, for example, by applying a negative electrode active material to at least a portion of at least one surface of the copper plate, and the remaining portion of the copper plate to which the negative electrode active material is not applied may be negatively charged.

The separator may be any one selected from the group consisting of polyethylene (PE), polystyrene (PS), polypropylene (PP), and a copolymer of polyethylene (PE) and polypropylene (PP) (PVDF-HFP co-polymer) to a polyvinylidene fluoride-hexafluoropropylene copolymer.

The electrolyte solution may include, for example, a non-aqueous organic solvent and a lithium salt to facilitate the movement of lithium ions in the electrode assembly.

The lithium salt dissolves in the organic solvent, acts as a source of lithium ions in the secondary battery, and can promote the movement of lithium ions between the anode and the cathode.

Examples of the lithium salt include lithium salts such as LiPF6, LiBF4, LiSbF6, LiAsF6, LiCF3SO3, LiN (CF3SO2) 3, Li (CF3SO2) 2N, LiC4F9SO3, LiClO4, LiAlO4, LiAlCl4, LiN (CxF2x + And y is a natural number), LiCl, LiI, and lithium bisoxalate borate, or the like as a supporting electrolyte salt.

The concentration of the lithium salt in the electrolytic solution may vary depending on the application, and is usually within the range of 0.1 M to 2.0 M.

The organic solvent serves as a medium through which ions involved in the electrochemical reaction of the battery can move. Examples of the solvent include benzene, toluene, fluorobenzene, 1,2-difluorobenzene, 1,3- Difluorobenzene, 1,2-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-trichlorotol 1,2-diiodotoluene, 1,2-diiodotoluene, 1,3-diiodotoluene, 1,4-diiodotoluene, 1,2,3-triiodotoluene, 1,2,4- Triiodotoluene, R-CN (wherein R is a straight, branched or cyclic hydrocarbon group having 2 to 50 carbon atoms, and the hydrocarbon group may include a double bond, an aromatic ring, an ether bond or the like Dimethylformamide, dimethyl acetate, xylene, cyclohexane, tetrahydrofuran, 2-methyltetrahydrofuran, cyclohexanone, ethanol, isopropyl alcohol, dimethyl carbonate, ethylmethyl carbonate, diethyl carbonate, methyl propyl carbonate , Propylene carbonate, methyl propionate, ethyl propionate, methyl acetate, ethyl acetate, propyl acetate, dimethoxyethane, 1,3-dioxolane, diglyme, tetraglyme, ethylene carbonate, Ropil butylene carbonate, gamma-butyrolactone include, sulfolane (sulfolane), valerolactone, big surprise grade or type of mevalolactone or different than, but is not limited to this.

The positive electrode electrode is electrically connected to the positive electrode uncoated portion, the negative electrode electrode is electrically connected to the negative electrode uncoated portion, and the electrode lead 5 is electrically connected to the positive electrode and the negative electrode, respectively.

The casing member 110 may be a pouch for accommodating the electrode assembly 3 and an electrolytic solution (not shown) therein, or may be a round or square can.

Hereinafter, for the sake of convenience of description, pouches will be described as an example of the exterior material, and the pouch will be referred to as an exterior material.

The exterior material 110 may be formed by sequentially laminating polyethylene terephthalate (PET), nylon, aluminum (Al), and polypropylene (PP).

A housing space 110b may be formed inside the case 110 having an opening 110a at one side thereof and an electrode assembly 3 and an electrolyte solution may be accommodated in the housing space 110b, ) Is closed with a lid (111).

A sealing portion 120 such as a polypropylene material is formed between the casing member 110 and the lid 111 to finally seal the casing member 110 to seal the casing member 110 and the lid 111 have.

2, since the aluminum material forming the casing material 110 has water-tightness, moisture can not penetrate into the casing material 110 in the vertical direction of the secondary battery.

However, moisture permeating in the horizontal direction (or side surface) of the case member 110 is diffused into an unspecified area of the sealing member 120 that seals the case member 110, and is permeated into the case member 110.

The coating layer 130 may be formed on the sealing part 120 so as to increase the density of the sealing part 120 in order to prevent moisture from being transmitted to the sealing part 120 in the horizontal direction As shown in FIG.

The coating layer 130 is applied to the sealing portion 120 and coated on the sealing portion 120. The coating layer 130 may be applied to the sealing portion 120 so that the covering material 110 and the cover 111 And may be applied to the casing member 110 or the lid 111. [0053]

The electrode lead 5 of the electrode assembly 3 is exposed to the outside of the casing 110 through the opening 110a of the casing 110. When the lid 111 contacts the opening 110a of the casing 110 The electrode lead 5 penetrates between the casing member 110 and the lid and is exposed to the outside.

When the sealing part 120 is formed between the casing member 110 and the casing 111 to seal between the casing member 110 and the casing 111, the sealing member 120 passes between the casing member 110 and the casing 111 The electrode lead 5 is in contact with the electrode lead 5 so that the gap between the electrode lead 5 and the lid 111 or between the electrode lead 5 and the lid 110 or between the lid 111 and the electrode lead 5 and the lid 110 Lt; / RTI >

The coating layer 130 is applied to an end portion of the sealing portion 120 where the electrode lead 5 is in contact with the sealing portion 120 to increase the density of the portion where the sealing portion 120 and the electrode lead 5 are in contact with each other.

The coating layer 130 may be formed of silicon dioxide (SiO2), aluminum oxide (Al2O3), zinc oxide (ZnO), magnesium fluoride (MgF2), or the like, which can be applied to the sealing part 120 to improve the density of the sealing part 120. [ Titanium dioxide (TiO2), or the like, to maximize the water tightness of the sealing portion 120.

4 to 5 are views showing that the coating layer is applied to only a part of the sealing portion according to another embodiment of the present invention.

The coating layer 130 may be applied to the entire outer periphery of the sealing portion 120 as in the embodiment of the present invention shown in Figs. 2 to 3, but in some cases, It is possible to selectively apply only to a part of the outer circumference of the sealing part 120 where moisture can permeate to reduce the cost.

5, according to another embodiment of the present invention, the coating layer 130 is selectively applied only to the corner of the outer circumference of the sealing portion 120, and the sealing portion 120 So that the watertightness at the corner side where the watertightness may be lowered relatively can be reinforced.

6 to 9 are views showing that the coating layer is applied to only one side of the sealing portion according to another embodiment of the present invention.

As shown in FIG. 6, according to another embodiment of the present invention, the coating layer 130 may be applied only to the front side of the sealing portion 120 to prevent moisture from penetrating into the front surface of the secondary battery.

Alternatively, as shown in FIG. 7, according to another embodiment of the present invention, the coating layer 130 may be applied only around the left side of the sealing portion 120 to prevent water from penetrating into the left side of the secondary battery. have.

Alternatively, as shown in FIG. 8, according to another embodiment of the present invention, the coating layer 130 may be applied only on the right side of the sealing portion 120 to prevent moisture from penetrating to the right side of the secondary battery .

Alternatively, as shown in FIG. 9, according to another embodiment of the present invention, the coating layer 130 may be applied only on the rear side of the sealing portion 120 to prevent moisture from penetrating into the back surface of the secondary battery have.

As in the above-described embodiments of the present invention, in the environment in which the secondary battery is installed, the coating layer 130 is selectively applied only to the portion where the water tightness of the secondary battery needs to be strengthened so that moisture permeates into the secondary battery And the manufacturing cost of the secondary battery can be reduced by reducing the cost.

Although the coating layer 130 is exaggerated in FIGS. 2 to 9, since the coating layer 130 of the present invention has such a volume that it is hard to be visually recognized, the coating layer 130 is formed on the outer periphery of the sealing portion 120 The volume of the sealing portion 120 is hardly changed, so that the energy density of the secondary battery is not lowered.

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

10 is a flowchart sequentially illustrating a method of manufacturing a secondary battery according to an embodiment of the present invention.

10, a method of manufacturing a secondary battery according to an embodiment of the present invention includes a receiving step S1, a finishing step S2, a sealing step S3, and a coating step S4.

The receiving step S1 is a step of receiving the electrode assembly and the electrolytic solution inside the casing through the opening of the casing.

The finishing step S2 is a step of closing the opening of the casing with a lid or the like after housing the electrode assembly and the electrolyte in the casing.

At this time, the electrode lead of the electrode assembly is closed by using a cover so that the electrode lead is exposed to the outside of the casing through the opening of the casing.

The sealing step S3 is a step of closing the opening of the casing with a cover, sealing between the casing and the cover, and finally sealing.

In the coating step S4, silicon dioxide (SiO2), aluminum oxide (Al2O3), zinc oxide (ZnO), magnesium fluoride (MgF2), and titanium dioxide (TiO2) are formed on the outer peripheries of the end portions of the sealing portions sealed between the casing and the lid TiO2), or the like, which is an inorganic mixed thin film layer.

In the coating step S4, the coating layer coated on the sealing part increases the density of the sealing part, thereby maximizing the water tightness of the sealing part.

The electrode lead exposed to the outside through the opening is sealed between the lid and the casing and is sealed in the sealing step S3. In the coating step S4, the coating liquid is applied to a portion sealing the electrode lead, Strengthen the watertightness of the area where the leads are located.

As described above, according to the present invention, a coating layer is formed on the sealing portion to improve water tightness.

According to the present invention, there is an effect of increasing the density of the sealing portion by forming a coating layer of the inorganic mixed thin film layer on the sealing portion.

According to the present invention, it is possible to selectively form a coating layer only on a part of the sealing part where water tightness is required, thereby reducing manufacturing costs.

Although the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, Various modifications and variations are possible to those skilled in the art.

3: electrode assembly
5: Electrode lead
110: exterior material
110a: opening
111: Cover
120: sealing part
130: Coating layer

Claims (10)

(110) having an opening (110a) on one side and housing the electrode assembly (3) having the electrode leads (5) formed thereon;
A lid 111 provided to close the opening 110a;
A sealing part 120 sealed to seal between the casing member 110 and the lid 111; And
A coating layer (130) coated on the sealing part (120) to make the sealing part (120) water tight; And a secondary battery. The method according to claim 1,
Wherein the coating layer (130) is an inorganic mixed thin film layer. The method of claim 2,
Wherein the inorganic mixed thin film layer is formed by mixing at least one of silicon dioxide (SiO2), aluminum oxide (Al2O3), zinc oxide (ZnO), magnesium fluoride (MgF2), and titanium dioxide (TiO2) Car battery. The method according to claim 1,
Wherein the coating layer (130) is provided at an end of the sealing part (120). The method according to claim 1,
Wherein the coating layer (130) is applied only to a part of the sealing portion (120). The method according to claim 1,
Wherein the coating layer (130) is provided at an end of the sealing part (120) in contact with the electrode lead (5). The method according to claim 1,
Wherein the coating layer (130) is formed at a corner of the sealing part (120). A receiving step (S1) of receiving the electrode assembly through the opening of the casing member in the casing;
A finishing step (S2) of finishing the opening of the exterior material;
A sealing step (S3) of sealing the finished portion of the exterior material; And
A coating step (S4) of water-tightly coating the sealed part of the exterior material; Including,
Wherein the coating step (S4) increases the density of the sealed portion of the casing. The method of claim 8,
Wherein the finishing step (S2) is performed by using the lid so that the electrode lead of the electrode assembly is exposed to the outside through the opening of the casing. The method of claim 9,
Wherein the coating step (S4) comprises coating a coating liquid on a sealed portion between the outer casing and the cover through which the electrode lead passes, thereby forming a coating layer.

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