KR20210099765A - Thin lithium battery and method for manufacturing thereof - Google Patents

Abstract

The present invention relates to a thin lithium battery and a method for manufacturing the same, and specifically, to a thin lithium battery having a tabless current collecting structure that does not require a separate tab or terminal unit because a current collector is exposed to the outside, and a method for manufacturing the same. In addition, the present invention relates to a thin lithium battery that has flexibility to be applied to a flexible device, and does not require a separate terminal unit to be manufactured by punching such as cutting, stamping, or laser cutting and the like to diversify dimensions and designs, and a method for manufacturing the same.

Description

Thin lithium battery and manufacturing method thereof

The present invention relates to a thin lithium battery and a method for manufacturing the same, and specifically, the present invention relates to a thin lithium battery having a tabless current collector structure that does not require a separate tab or terminal part because a current collector is exposed to the outside, and a method for manufacturing the same it's about In addition, since it has flexibility, it can be applied to flexible devices, and since it does not require a separate terminal part, it is possible to diversify dimensions and designs by manufacturing by punching such as cutting, stamping, or laser cutting, and a method for manufacturing the same is about

Energy-related technologies are being actively studied as the industry related to portable electronic devices is expanding due to the recent development of communication technology and semiconductor manufacturing technology, and the demand for the development of alternative energy to prepare for the depletion of fossil fuels and to preserve the environment is rapidly increasing. . Among these energy-related technologies, a battery, which is a representative energy storage device, is at the center.

Among batteries, a lithium primary battery has a higher voltage and higher energy density than a conventional aqueous-based battery, so it is easy to reduce the size and weight and is widely applied. Such a lithium primary battery is mainly used for a main power source or a backup power source of a portable electronic device. Another battery, a lithium secondary battery, is an energy storage device capable of charging and discharging using an electrode material having excellent reversibility.

Lithium secondary batteries are being manufactured in various shapes according to their applications. For example, the lithium secondary battery is packaged and manufactured in a cylindrical shape, a prismatic shape, and a pouch shape. Here, since the pouch-type secondary battery can be lightened, related technologies are being continuously developed. In general, a pouch-type lithium secondary battery accommodates an electrode assembly in a pouch case having a space for accommodating the electrode assembly, then seals the pouch case to form a bare cell, and the pouch is placed in the bare cell. It may be manufactured by attaching accessories such as a protective circuit module to form a pouch core pack.

However, such a pouch-type lithium secondary battery also becomes a factor limiting the shape and size of the lithium secondary battery in terms of packaging, and since the conventional pouch-type lithium secondary battery includes electrode tabs, each electrode must be connected to the tab. , there are problems in that it is impossible to package several at a time, manufacturing is difficult, productivity is lowered, and it is difficult to apply to various electronic products.

In addition, in the era of the Internet of Things (IoT), the demand for thin power sources of various designs that can be used in low-power, small-capacity devices is increasing, but the existing coin cells have a uniform design and thick thickness. has a disadvantage. In addition, the conventional pouch thin battery also has a uniform design and has a tab, so production is complicated and the price is high. Accordingly, there is a need for a power source having a free shape and a thin thickness and competitive price.

Korean Patent Publication No. 10-1621410 (2016.05.10)

As devised to solve the above-described problems, an object of the present invention is to provide a thin lithium battery having the effect of reducing mass production and production cost by continuously manufacturing the battery and packaging process. .

In addition, an object of the present invention is that the negative electrode current collector and the upper sheet are sealed by the first partition wall and the second partition wall, and the first partition wall protrudes to the inside of the battery compared to the second partition wall so that a direct connection between the positive electrode and the negative electrode current collector is provided. An object of the present invention is to provide a thin lithium battery capable of preventing a short circuit by connecting a positive electrode and a negative electrode due to excessive formation of lithium metal during charging and discharging by preventing contact, and a method for manufacturing the same.

In addition, one object of the present invention is a thin lithium battery that does not require a separate tab or terminal part because the current collector is exposed to the outside or a metal layer constituting a package electrically connected to the current collector is exposed to the outside, and a method for manufacturing the same would like to provide

In addition, an object of the present invention is to provide a thin lithium battery capable of reducing material costs by not requiring a separate packaging material for the anode and a method for manufacturing the same. That is, an object of the present invention is to provide a thin lithium battery in which an anode current collector can substantially serve as a packaging material and a method for manufacturing the same.

In addition, an object of the present invention is to manufacture a thin lithium battery capable of diversifying the design of the battery by manufacturing it in various shapes such as a circle, a semi-circle, a triangle, a square, and a star without any restrictions on the design of the battery without the need for a terminal part, and manufacturing the same We want to provide a way

In addition, an object of the present invention is to use a negative electrode current collector having a plurality of battery cell regions by a barrier rib pattern, arrange a plurality of separators and positive electrodes in the cell region, and laminate the upper sheet by heat, An object of the present invention is to provide a thin lithium battery capable of forming a plurality of battery cells at once and dividing the battery cells to facilitate manufacturing of a plurality of batteries, and a method for manufacturing the same.

In addition, the present invention is to provide a thin lithium battery having a tabless current collecting structure in which the metal layer containing lithium is not exposed to the atmosphere during the battery assembly process, thereby suppressing the formation of a surface oxide film, and having a reduced current collecting resistance, and a method for manufacturing the same. .

In order to achieve the above object, the present invention provides a thin lithium battery having a tabless current collector structure.

A specific aspect of the present invention is that the upper sheet, the positive electrode, the separator and the negative electrode current collector are sequentially stacked,

The positive electrode is a positive electrode-electrolyte assembly in which a positive electrode active material layer including a lithium composite oxide and a first gel polymer electrolyte are integrated on a positive electrode current collector, and the positive electrode current collector is in close contact with the upper sheet,

The separator is substantially the same size as the positive electrode or larger than the positive electrode,

The negative electrode current collector includes a first partition wall on the periphery of the upper surface,

and a second barrier rib on the upper portion of the first barrier rib to be sealed in close contact with the upper sheet,

The inner surface of the first partition wall is formed to have a larger width to protrude inward than the inner surface of the second partition wall,

The anode and the separator are accommodated in a space formed by sealing the second partition wall and the upper sheet, and the periphery of the lower surface of the separator is in close contact with the upper surface of the protruding portion of the first partition wall,

A thin lithium battery including a lithium metal layer integrated with the anode current collector and a second gel polymer electrolyte between the anode current collector and the separator inside the first partition wall.

Another aspect of the present invention is

(S1) preparing a positive electrode-electrolyte assembly including a first gel polymer electrolyte by applying and gelling the first gel polymer electrolyte composition on the positive electrode;

(S2) preparing a separation membrane;

(S3) cutting the positive electrode-electrolyte assembly and the separator;

(S4) laminating a first barrier rib sheet having a barrier rib pattern partitioned into a cell region having one or a plurality of openings on an upper surface of the anode current collector;

(S5) laminating a second partition wall sheet having a larger opening than that of the first partition wall sheet on the first partition wall sheet;

(S6) forming a second gel polymer electrolyte on the negative electrode current collector by injecting and gelling a second gel polymer electrolyte composition into each of one or a plurality of cell regions of the first partition wall sheet;

(S7) arranging a separator and a positive electrode-electrolyte assembly in each of one or a plurality of cell regions of the second barrier rib sheet to form a structure in which a negative electrode current collector, a separator, and a positive electrode-electrolyte assembly are stacked;

(S8) laminating an upper sheet on the laminated structure; and

(S9) charging one or a plurality of cells;

A method of manufacturing a thin lithium battery comprising a.

According to the present invention, a battery can be manufactured by a relatively simple method such as coating, lamination, and injection, and by adjusting the size of the first partition wall, direct contact between the positive electrode and the negative electrode current collector can be blocked, and accordingly, generated during charging and discharging There is an effect that can block the occurrence of a short circuit of the battery by the lithium metal layer.

The present invention is manufactured by arranging a separator and a positive electrode punched in a predetermined shape to be accommodated in the plurality of cell regions on a negative electrode current collector having a plurality of cell regions that are continuously supplied, so that a thin lithium battery can be continuously produced. It has the effect of greatly improving productivity. In addition, using a gel polymer electrolyte without using a liquid electrolyte, a battery can be manufactured by a relatively easy and simple method such as application and injection without a vacuum process, and the production speed can be improved with a simplified process.

The present invention has the advantage that the current collector is exposed to the outside and does not require a separate tab or terminal portion, does not require consideration of the size and location of the terminal portion, and has a cost reduction effect by removing the terminal portion. In addition, it is possible to manufacture thin lithium batteries of various shapes and dimensions, such as circular, semicircular, triangular, square, and star-shaped, by a method such as punching or laser cutting.

The present invention has a structure in which at least one surface of the negative electrode current collector exposed to the outside extends in the plane direction and also serves as a packaging material, and it does not require a packaging layer provided in addition to the outermost layer of the negative electrode current collector like a conventional battery. can

In addition, the present invention can reduce the grain boundary resistance of the battery by using the positive electrode and the separator in which the gel polymer electrolyte is integrated, and can improve the ionic conductivity, thereby providing a more advantageous effect to the implementation of improved lifespan characteristics and improved safety. .

1 is a cross-sectional view of a thin lithium battery according to an embodiment of the present invention.
2 is a cross-sectional view of a thin lithium battery according to an embodiment of the present invention.
3 is a cross-sectional view of a thin lithium battery according to an embodiment of the present invention, illustrating a case in which a junction is formed at a portion where an upper sheet and a positive electrode current collector are in close contact.
4 is a cross-sectional view of a thin lithium battery according to an embodiment of the present invention, illustrating a case in which a conductive layer is included between an upper sheet and a positive electrode current collector.
5 is a cross-sectional view of a thin lithium battery according to an embodiment of the present invention, and shows a case in which the lower surface of the anode current collector further includes a lower sheet adhered in close contact with the anode current collector.
6 is an SEM photograph of observing the surface of a lithium metal layer formed on a negative electrode current collector when a gel polymer electrolyte is used.
7 is an SEM photograph of observing the surface of a lithium metal layer formed on a negative electrode current collector when a liquid electrolyte is used.

Hereinafter, the present invention will be described in more detail through embodiments or examples including the accompanying drawings. However, the following specific examples or examples are only a reference for describing the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

Also, unless defined otherwise, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description herein is for the purpose of effectively describing particular embodiments only and is not intended to limit the invention.

Also, the singular forms used in the specification and appended claims may also be intended to include the plural forms unless the context specifically dictates otherwise.

In addition, when a part "includes" a certain component, this means that other components may be further included rather than excluding other components unless otherwise stated.

As used herein, the term 'thin lithium battery' refers to a thin battery in which a positive electrode, a separator, and a negative electrode are stacked, specifically, a film-type lithium battery having a thickness of 1 mm or less capable of electrochemical reaction. In addition, since the positive electrode and the negative electrode are configured in the form of a thin film, the battery itself may have very flexible properties.

As used herein, the term “substantially” means that the error range is within ±10 μm. That is, the substantially coincident edge means that the edges are completely coincident or that the error range is within ±10 μm.

As used herein, the term 'conjugate' means chemically and physically combined and integrated. “Electrolyte binder” means that a gel polymer electrolyte is coated or injected on a positive electrode or a separator, and then cured or gelled and integrated.

As used herein, the term 'laminate' means that each layer is chemically and physically bonded while being stacked.

As used herein, the term 'gelation' refers to physical crosslinking formed by entanglement between polymer chains or partial molecular orientation of polymer chains, chemical crosslinking according to the network structure entangled by chemical bonds, or physical It means a complex cross-linking in which cross-linking and chemical cross-linking are mixed.

As used herein, the term 'different in ionic conductivity' means a difference in ionic conductivity of 0.1 mS/cm or more due to a difference in the type, concentration, or content of materials constituting the gel polymer electrolyte. A method of measuring the ionic conductivity will be described in more detail in Examples below.

In one aspect of the present invention, the upper sheet, the positive electrode, the separator and the negative electrode current collector are sequentially stacked,

The positive electrode is a positive electrode-electrolyte assembly in which a positive electrode active material layer including a lithium composite oxide and a first gel polymer electrolyte are integrated on a positive electrode current collector, and the positive electrode current collector is in close contact with the upper sheet,

The separator is substantially the same size as the positive electrode or larger than the positive electrode,

The negative electrode current collector includes a first partition wall on the periphery of the upper surface,

and a second barrier rib on the upper portion of the first barrier rib to be sealed in close contact with the upper sheet,

The inner surface of the first partition wall is formed to have a larger width to protrude inward than the inner surface of the second partition wall,

The anode and the separator are accommodated in a space formed by sealing the second partition wall and the upper sheet, and the periphery of the lower surface of the separator is in close contact with the upper surface of the protruding portion of the first partition wall,

A thin lithium battery including a lithium metal layer integrated with the anode current collector and a second gel polymer electrolyte between the anode current collector and the separator inside the first partition wall.

In one aspect of the present invention, the separator may be one in which a gel polymer electrolyte is integrated.

In one aspect of the present invention, the first partition wall may have a thickness of 1 to 50 μm.

In one aspect of the present invention, the first partition wall may include a polar polyolefin-based resin.

In one aspect of the present invention, the first partition wall and the peripheral portion of the lower surface of the separator may further include a lithium metal layer in close contact.

In one aspect of the present invention, the upper sheet may be made of a metal layer, and the positive electrode current collector and the metal layer may be in close contact with each other to be electrically connected.

In one aspect of the present invention, at least one or more bonding portions may be further included in a portion in which the positive electrode current collector and the metal layer are in close contact.

In one aspect of the present invention, any one or more conductive layers selected from a conductive adhesive layer, a conductive adhesive layer, a conductive paste layer, and an anisotropic conductive layer may be further included between the positive electrode current collector and the metal layer.

In one aspect of the present invention, the upper sheet may further include an insulating layer on an outermost layer, and a portion of the insulating layer may be open.

In one aspect of the present invention, the upper sheet is a laminate including a barrier layer and a sealing layer,

The barrier layer is made of a metal foil or a polymer material,

The sealing layer is made of an insulating material, and is made of a material that can be adhered in close contact with the upper surface of the positive electrode current collector and the partition wall,

An opening may be formed in a portion of the upper sheet so that a portion of the positive electrode current collector is exposed to the outside.

In one aspect of the present invention, the upper sheet may further include a substrate layer made of an insulating material on the barrier layer.

In one aspect of the present invention, the lithium metal layer may have a thickness of 1 to 100 μm.

In one aspect of the present invention, the lithium metal layer may have a porous dense flat structure.

In one aspect of the present invention, the negative electrode current collector may be any one or a combination of two or more selected from the group consisting of aluminum, stainless steel, copper, nickel and titanium.

In one aspect of the present invention, the negative electrode current collector is a laminate including a first negative electrode metal layer and a second negative electrode metal layer,

The first anode metal layer is any one or a combination of two or more selected from the group consisting of copper, nickel and stainless steel,

The second anode metal layer is any one or a combination of two or more selected from the group consisting of aluminum, stainless steel, copper, nickel and titanium,

The first cathode metal layer and the second cathode metal layer may have different compositions.

In one aspect of the present invention, the negative electrode current collector may further include a terminal portion extending further than the outer end of the first partition wall.

In one aspect of the present invention, the metal layer of the upper sheet may further include a terminal portion extending more than the outer end of the second partition wall.

In one aspect of the present invention, the positive electrode current collector is a laminate including a first positive electrode metal layer and a second positive electrode metal layer,

The first anode metal layer and the second anode metal layer may have different compositions.

In one aspect of the present invention, the first gel polyelectrolyte and the second gel polyelectrolyte include a solvent and a dissociable salt,

The first gel polymer electrolyte and the second gel polymer electrolyte may be a polymer matrix further comprising any one or two or more selected from the group consisting of linear polymers and crosslinked polymers.

In one aspect of the present invention, the first gel polymer electrolyte may be gelled after application and integrated with the positive electrode active material layer.

In one aspect of the present invention, the second gel polymer electrolyte may be gelled after application or injection and distributed on the negative electrode current collector inside the first partition wall.

In one aspect of the present invention, the first gel polymer electrolyte and the second gel polymer electrolyte may each have different ionic conductivity.

In one aspect of the present invention, the ionic conductivity IC ₁ of the first gel polymer electrolyte and the ionic conductivity IC ₂ of the second gel polymer electrolyte may satisfy Equation 1 below.

[Formula 1]

IC ₁ - IC ₂ ≥ 0.1 mS/cm

In one aspect of the present invention, the first gel polymer electrolyte and the second gel polymer electrolyte may include a solvent; the type or concentration of the dissociable salt; linear polymer type or content; cross-linked polymer type or content; At least one of them may be different.

In one aspect of the present invention, the first gel polymer electrolyte and the second gel polymer electrolyte further include a performance enhancing agent, and the performance enhancing agent of the first gel polymer electrolyte and the second gel polymer electrolyte may be of different types or concentrations. there is.

In one aspect of the present invention, it may further include a lower sheet adhered in close contact with the negative electrode current collector, and an opening is formed in a portion of the lower sheet so that a portion of the negative electrode current collector is exposed to the outside.

Another aspect of the present invention is a method for manufacturing a thin lithium battery,

(S1) preparing a positive electrode-electrolyte assembly including a first gel polymer electrolyte by applying and gelling the first gel polymer electrolyte composition on the positive electrode;

(S2) preparing a separation membrane;

(S3) cutting the positive electrode-electrolyte assembly and the separator;

(S4) laminating a first barrier rib sheet having a barrier rib pattern partitioned into a cell region having one or a plurality of openings on an upper surface of the anode current collector;

(S5) laminating a second partition wall sheet having a larger opening than that of the first partition wall sheet on the first partition wall sheet;

(S6) injecting and gelling a second gel polymer electrolyte composition into each of one or a plurality of cell regions of the first partition wall sheet;

(S7) arranging a separator and a positive electrode-electrolyte assembly in each of one or a plurality of cell regions of the second barrier rib sheet to form a structure in which a negative electrode current collector, a separator, and a positive electrode-electrolyte assembly are stacked;

(S8) laminating an upper sheet on the laminated structure; and

(S9) charging one or a plurality of cells;

includes

In one aspect of the manufacturing method of the present invention, the step (S2) comprises the steps of applying and gelling a gel polymer electrolyte composition on the separator to prepare a separator-electrolyte complex comprising a gel polymer electrolyte;

In the steps (S3) and (S7), the separator may be the separator-electrolyte combination.

In one aspect of the manufacturing method of the present invention, in the step (S9), a lithium metal layer may be formed between the negative electrode current collector and the second gel polymer electrolyte by charging.

Hereinafter, each configuration of the present invention will be described in more detail with reference to the drawings.

In the thin lithium battery according to an aspect of the present invention, since the negative electrode current collector is exposed to the outside, and the upper sheet in close contact with the positive electrode current collector may be made of a metal layer, a separate terminal part may not be required. However, since a separate terminal part may be further added if necessary, this is not excluded. As it does not require a separate terminal part, it has a feature that it can be manufactured in various sizes and shapes. In addition, since it is thin and flexible, it can be applied to various fields. In addition, an integrated lithium metal layer is formed on the negative electrode current collector by charging, and the electron distribution of the lithium metal layer can be more uniformly formed due to such a structure.

In addition, even when lithium ions are deposited under a low current density (low charging rate), lithium ions released from the positive electrode can be easily captured, and lithium ions returned to the positive electrode can be recaptured. Even in this case, uniform deposition by a large number of lithium ions is possible, so that an ultra-thin coating, that is, an ultra-thin lithium metal layer, can be provided as an anode integrated with the anode current collector inside the battery.

In addition, since the periphery of the lower surface of the separator is in close contact with the protruding portion of the inner surface of the first partition wall by the above structure, it prevents short circuit defects caused by misalignment of the separator during the battery assembly process, thereby reducing mass production and production costs It is possible to provide a thin lithium battery and a method for manufacturing the same.

In addition, after the positive electrode and the separator are stacked and cut by a method such as punching, the battery can be manufactured by being accommodated on the first partition wall and sealing, so that the manufacturing is simple and easy.

In addition, with the above structure, the periphery of the lower surface of the separator is in close contact with the protruding part on the inner surface of the first partition wall to physically support it, and as an electrolyte reservoir, the amount of gel polymer electrolyte on the surface of the negative electrode is relatively There is an effect of preventing deterioration of battery performance due to depletion of electrolyte when the lithium metal layer is formed.

In addition, the periphery of the lower surface of the separator is in close contact with the protruding portion on the inner surface of the first barrier rib by the above structure, thereby suppressing an increase in cell interface resistance that may occur during mechanical deformation or high-temperature driving due to physical stress. .

First, the laminated structure of the thin lithium battery of the present invention will be described in detail with reference to the drawings. 1 to 5 illustrate one embodiment of the present invention, but is not limited thereto.

[First aspect of thin lithium battery]

1 is a cross-sectional view of a thin lithium battery 1000 according to a first aspect of the present invention.

The thin lithium battery 1000 according to the first aspect of the present invention has a structure in which the negative electrode current collector 30 is exposed to the outside as shown in FIG. 1 . Specifically, the upper sheet 50 , the positive electrode 10 , the separator 20 and the negative electrode current collector 30 are sequentially stacked from the top, and the negative electrode collector is disposed between the negative electrode current collector 30 and the separator 20 . It includes a lithium metal layer 60 integrated with the whole. In this case, the upper sheet 50 and the negative electrode current collector 30 may be sealed and sealed by the first partition wall 41 and the second partition wall 42 , and the first partition wall 41 is the second partition wall 42 . ), the inner surface of the first barrier rib 41 has a larger width to protrude inward than the inner surface of the second barrier rib, and the protruding portion 411 of the first barrier rib ), the peripheral portion 211 of the lower surface of the separation membrane is in close contact with the upper surface.

As shown in FIG. 1 , as the inner surface of the first partition wall 41 protrudes inward to accommodate the peripheral portion 211 of the lower surface of the separation membrane and has an inner protrusion 411 , the peripheral portion is the inner projection of the first partition wall. The lithium metal layer is not formed on the negative electrode current collector at the lower part of the periphery during charging and discharging, so it is possible to block the short circuit caused by this, and when the battery is used, It is possible to prevent a short circuit, which has the effect of further improving the stability of the electrochemical device.

In addition, the inner protrusion 411 serves to physically support the positive electrode and the separator, and as an electrolyte reservoir, it is possible to relatively increase the amount of gel polymer electrolyte on the surface of the negative electrode, so that when the lithium metal layer is formed, the electrolyte is depleted. There is an effect of preventing deterioration of battery performance due to

More specifically, in the first aspect of the present invention, the upper sheet 50, the positive electrode 10, the separator 20 and the negative electrode current collector 30 are sequentially stacked,

The positive electrode 10 is a positive electrode-electrolyte combination having a positive electrode active material layer including a lithium composite oxide and a composite active material layer 12 in which a first gel polymer electrolyte is integrated on a positive electrode current collector 11, and the positive electrode current collector Reference numeral 11 is in close contact with the upper sheet 50 , the separator 20 has substantially the same size as the positive electrode 10 or is larger than the positive electrode 10 , and the negative electrode current collector 30 has a periphery 31 of the upper surface ) includes a first partition wall 41,

A second partition wall 42 is included on the first partition wall 41 to be sealed in close contact with the upper sheet, and an inner surface of the first partition wall 41 is greater than the inner surface of the second partition wall 42 . The positive electrode 10 and the separator 20 are accommodated in the space formed by sealing the second partition wall 42 and the upper sheet 50 and having a large width to protrude inwardly (411), and the second partition wall 42 and the upper sheet 50 are sealed. The peripheral portion 211 of the lower surface of the separator is in close contact with the upper surface of the protruding portion 411 of the first partition wall 41 , and the negative electrode is disposed between the negative electrode current collector 30 and the separator 20 inside the first partition wall. and a lithium metal layer 60 integrated with the current collector and a second gel polymer electrolyte. The second gel polymer electrolyte may exist between the lithium metal layer 60 and the separator 20, and as the lithium metal layer is formed on the anode current collector by initial charging, the second gel polymer electrolyte has a porous dense flat structure. It can be distributed in the lithium metal layer and on the surface of the lithium metal layer. In addition, as the separator is in close contact with the portion protruding from the inner surface of the first partition wall 41, it is possible to block direct connection between the negative electrode current collector and the positive electrode, and the lithium metal layer formed during initial charging is the first partition wall ( 41) may be formed in a portion other than the protruding portion on the inner surface.

The overall thickness of the thin lithium battery according to an aspect of the present invention may be 100 to 2000 μm, more preferably 150 to 1500 μm, and even more preferably 200 to 1200 μm, but is not limited thereto, but is not limited thereto. It is possible to manufacture with a flexible battery, and it is possible to provide a flexible battery.

Hereinafter, each configuration constituting the thin lithium battery of the first aspect of the present invention will be described in more detail.

<Upper seat (50)>

One aspect of the upper sheet 50 may be made of a metal layer, and the positive electrode current collector 11 and the metal layer may be in close contact with each other to be electrically connected. At this time, since the negative electrode current collector 30 is also exposed to the outside, a separate tab or terminal part may not be required.

In addition, although not shown separately, in the first aspect, a separate tab or terminal portion may be further included, and the metal layer of the upper sheet 50 includes a terminal portion extending further in the surface direction than the outer end of the second partition wall 42 . may include more. In this case, the terminal part may be one in which the metal layer is further extended or a separate metal layer is further connected to the metal layer. In addition, the negative electrode current collector 30 may further include a terminal portion extending further in the plane direction than the outer end of the first partition wall 41 . In this case, the terminal part may be a further extension of the anode current collector 30 or a further connection of a separate metal layer to the anode current collector 30 .

Another aspect of the upper sheet 50 is made of a metal layer, and may further include at least one bonding portion at a portion in which the positive electrode current collector and the metal layer are in close contact. This is illustrated in FIG. 3 . That is, as shown in FIG. 3 , in the first aspect, the positive electrode current collector 11 and the metal layer of the upper sheet 50 are in close contact with at least one bonding portion 51 may be further included. there is. Since contact resistance can be reduced by forming the junction, electrical performance can be further improved, charging and discharging efficiency can be improved, and output characteristics can be further improved. The bonding portion 51 may be formed on a portion where the metal layer of the upper sheet and the positive electrode current collector are in close contact, and may be formed only on a part or on the entirety, but may be formed on only a portion for ease of manufacture. . The joint 51 may be formed by welding, soldering, etc., but is not limited thereto. The welding may be formed in a spot or stripe shape by methods such as resistance welding, ultrasonic welding, and laser welding, but is not limited thereto. In addition, in the case of soldering, a soldering paste may be further included inside the upper sheet 50 made of a metal layer, that is, on a portion to which the electrode assembly is in close contact.

Another aspect of the upper sheet 50 is made of a metal layer, and at a portion in which the positive electrode current collector and the metal layer are in close contact, any one or more selected from a conductive adhesive layer, a conductive adhesive layer, a conductive paste layer, and an anisotropic conductive layer. It may further include a conductive layer. This is illustrated in FIG. 4 . The conductive adhesive layer, the conductive adhesive layer, the conductive paste layer and the anisotropic conductive layer are not limited as long as they are conventionally used in the relevant field, and the metal layer of the upper sheet and the positive electrode current collector can be better adhered to each other, and electricity is more You can make it work well. In addition, although not shown, the junction part 51 may be further included as shown in FIG. 3 if necessary.

Another aspect of the upper sheet 50 may be to further include an insulating layer (not shown) on the outer surface of the metal layer. By further including an insulating layer, it is possible to protect the electrode assembly from external materials from the outside of the metal layer, and to electrically insulate it from the outside. In this case, the insulating layer may include a groove in which the insulating layer is not formed as a part of the insulating layer is opened. The groove may be formed in a portion of the upper sheet 50 in close contact with the positive electrode current collector, and electricity may be transmitted to the outside through the groove. In this case, a separate terminal may be further included, but may be performed without a separate terminal.

The insulating layer (not shown) may be used without limitation as long as it is a material having electrical insulating properties, and if it can protect the electrode assembly from external materials from the outside of the metal layer and electrically insulate from the outside, it may be used without limitation. Specifically, for example, polyethylene, polypropylene, casted polypropylene (CPP), polystyrene, polyethylene terephthalate, polyvinyl chloride, polyvinylidene chloride, polyamide, cellulose resin, polyimide resin, etc. may be used. , but is not limited thereto. In addition, one layer or two or more layers may be laminated. In addition, although not shown, the junction part 51 may be further included as shown in FIG. 3 if necessary.

Another aspect of the upper sheet 50 may be a laminate (not shown) including a barrier layer and a sealing layer. In addition, if necessary, it may further include a substrate layer on the barrier layer. In addition, an opening may be formed in a portion of the upper sheet 50 so that a portion of the positive electrode current collector is exposed to the outside.

The barrier layer is to prevent penetration of water vapor, gas, etc. from the outside, and may be specifically made of, for example, metal foil. In addition to the metal foil, it may be a sheet or film made of a polymer resin having barrier properties. The metal foil is an alloy of iron (Fe), carbon (C), chromium (Cr) and manganese (Mn), an alloy of iron (Fe), carbon (C), chromium (Cr) and nickel (Ni), aluminum ( Al), copper (Cu) or an equivalent thereof may be used, but is not limited thereto. The thickness of the barrier layer is not limited, but may be, for example, 0.1 to 100 μm, more specifically 0.5 to 50 μm, and more preferably 1 to 10 μm.

The sealing layer is an innermost layer of the upper sheet and is in contact with the positive electrode current collector. In addition, it serves to heat-seal and seal the battery during manufacturing. The sealing layer may be made of an insulating material, and may be made of a material that can be thermally fused and adhered to the current collector. More specifically, it may be adhered in close contact with the current collector by heat compression. Therefore, sealing is possible by heat compression, and any material having electrical insulation may be used without limitation. Specific examples thereof include polyolefins, cyclic polyolefins, carboxylic acid-modified polyolefins, and carboxylic acid-modified cyclic polyolefins.

Specific examples of the polyolefin include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; polypropylenes such as homopolypropylene, a block copolymer of polypropylene (eg, a block copolymer of propylene and ethylene), and a random copolymer of polypropylene (eg, a random copolymer of propylene and ethylene); terpolymers of ethylene-butene-propylene; and the like.

The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefin as a constituent monomer of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, isoprene, and the like. .

Moreover, as a cyclic monomer which is a structural monomer of the said cyclic polyolefin, For example, Cyclic alkenes, such as norbornene; Specific examples thereof include cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene and norbornadiene.

The carboxylic acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of the polyolefin with carboxylic acid. As carboxylic acid used for modification, maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, itaconic anhydride, etc. are mentioned, for example.

The carboxylic acid-modified cyclic polyolefin refers to copolymerizing a part of the monomer constituting the cyclic polyolefin in place of α,β-unsaturated carboxylic acid or anhydride thereof, or α,β-unsaturated carboxylic acid or its anhydride with respect to the cyclic polyolefin. It is a polymer obtained by block polymerization or graft polymerization of an anhydride.

The said sealing layer may be formed individually by 1 type of resin component, and may be formed by the blend polymer which combined 2 or more types of resin components. In addition, it may be composed of only one layer, or may be formed of two or more layers by the same or different resin components.

The thickness of the sealing layer is not limited, but may be, for example, 1 to 100 μm, more specifically, 1 to 50 μm.

The base layer is a layer forming the outermost layer of the upper sheet. On the surface constituting the outermost layer of the base layer, if necessary, a hard coating layer for preventing scratches on the printed layer and the surface may be further formed.

The material for forming the base layer may be used without limitation as long as it has insulating properties. Specifically, for example, a resin such as a polyolefin resin, a polyester resin, a polyamide resin, an epoxy resin, an acrylic resin, a fluororesin, a polyurethane resin, a phenol resin, and a mixture or copolymer thereof can be used.

The base layer may be prepared in the form of a film or sheet of the above-described resin, and more specifically, may be a uniaxially or biaxially stretched film.

The thickness of the base layer is not limited, and may be, for example, 1 to 300 μm, more specifically 5 to 100 μm.

<Anode (10)>

In the first aspect of the present invention, the positive electrode 10 is a positive electrode in which a positive active material layer including a lithium composite oxide and a composite active material layer 12 in which a first gel polymer electrolyte is integrated is formed on a positive electrode current collector 11-electrolyte It may be a binder. The positive electrode-electrolyte combination may be obtained by applying a gel polymer electrolyte composition on the positive electrode active material layer, and then gelling it. By the gelation, the mechanical strength and structural stability of the positive electrode-electrolyte assembly may be improved, and the structural stability of the positive electrode interface may be improved.

The positive electrode current collector 11 is not limited as long as it is a substrate having excellent conductivity used in the technical field, and may be made of one including any one selected from a conductive metal, a conductive metal oxide, and the like. In addition, the current collector may be in a form in which the entire substrate is made of a conductive material, or a conductive metal, a conductive metal oxide, a conductive polymer, or the like is coated on one or both surfaces of the insulating substrate. In addition, the current collector may be made of a flexible substrate, and can be easily bent to provide a flexible electronic device. In addition, it may be made of a material having a restoring force that returns to its original shape after being bent. In addition, the current collector may be selected from the group consisting of a thin film form, a mesh form, an integrated form in which a thin film or mesh type current collector is laminated on one or both sides of a conductive substrate, and a metal-mesh composite. The metal-mesh composite is integrated by heat-compressing the thin-film metal and the mesh-like metal or polymer material, so that the metal thin film is integrated between the holes of the mesh so that the metal thin film does not break or crack even when bent. do. As described above, when the metal-mesh composite is used, it is more preferable to prevent cracks from occurring in the current collector during bending of the battery or during charging and discharging, but is not limited thereto. More specifically, for example, the current collector may be made of aluminum, stainless steel, copper, nickel, iron, lithium, cobalt, titanium, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and a composite thereof. , but is not limited thereto.

In one embodiment, the positive electrode current collector may be a laminate including a first positive electrode metal layer and a second positive electrode metal layer, and the first positive electrode metal layer and the second positive electrode metal layer may have different compositions.

The composite active material layer 12 may be one in which the positive electrode active material layer and the first gel polymer electrolyte are integrated, where 'integration' is a part or all of the active material layer by applying the first gel polymer electrolyte on the positive electrode active material layer. It means impregnating or forming the first gel polymer electrolyte layer on the surface of the active material layer. In a specific embodiment, after the positive electrode active material layer is formed on the positive electrode current collector, the first gel polymer electrolyte composition is applied on the positive electrode active material layer to be integrated.

The positive electrode active material layer is formed by coating the positive electrode active material composition on the positive electrode current collector, or by casting the positive electrode active material composition on a separate support, and then laminating a film obtained by peeling it from the support on the positive electrode current collector. It may be to manufacture a positive electrode having a positive electrode active material layer formed thereon. The thickness of the positive electrode active material layer is not limited, but may be 0.01 to 500 μm, more preferably 1 to 200 μm, but is not limited thereto.

The cathode active material composition is not limited, but may include a cathode active material, a binder, and a solvent, and may further include a conductive material.

The positive active material may be used without limitation as long as it is commonly used in the art. Specifically, for a lithium primary battery or a secondary battery, a compound capable of reversible intercalation and deintercalation of lithium (a lithiated intercalation compound) may be used. The positive active material of the present invention may be in the form of a powder.

Specifically, at least one of a composite oxide of lithium and a metal consisting of any one or a combination of two or more selected from cobalt, manganese, nickel, and the like may be used. Although not limited, as a specific example, a compound represented by any one of the following formulas may be used. Li _a A _1-b R _b D ₂ (wherein 0.90 ≤ a ≤ 1.8 and 0 ≤ b ≤ 0.5); Li _a E _1-b R _b O _2-c D _c (wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, and 0 ≤ c ≤ 0.05); LiE _2-b R _b O _4-c D _c (wherein 0 ≤ b ≤ 0.5 and 0 ≤ c ≤ 0.05); Li _a Ni _1-bc Co _b R _c D _α (wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05 and 0 < α ≤ 2); Li _a Ni _1-bc Co _b R _c O _2-α Z _α (wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05 and 0 < α <2); Li _a Ni _1-bc Co _b R _c O _2-α Z ₂ (wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05 and 0 < α <2); Li _a Ni _1-bc Mn _b R _c D _α (wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05 and 0 < α ≤ 2); Li _a Ni _1-bc Mn _b R _c O _2-α Z _α (wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05 and 0 < α <2); Li _a Ni _1-bc Mn _b R _c O _2-α Z ₂ (wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05 and 0 < α <2); Li _a Ni _b E _c G _d O ₂ (wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5 and 0.001 ≤ d ≤ 0.1); Li _a Ni _b Co _c Mn _d G _e O ₂ (wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.5 and 0.001 ≤ e ≤ 0.1); Li _a NiG _b O ₂ (wherein 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Li _a CoG _b O ₂ (wherein 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Li _a MnG _b O ₂ (wherein 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Li _a Mn ₂ G _b O ₄ (in the above formula, 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); QO ₂ ; QS ₂ ; LiQS ₂ ; V ₂ O ₅ ; LiV ₂ O ₅ ; LiTO ₂ ; LiNiVO ₄ ; Li _(3-f) J ₂ (PO ₄ ) ₃ (0 ≤ f ≤ 2); Li _(3-f) Fe ₂ (PO ₄ ) ₃ (0 ≤ f ≤ 2); and LiFePO ₄ .

In the above formula, A is Ni, Co, Mn, or a combination thereof; R is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P or a combination thereof; E is Co, Mn, or a combination thereof; Z is F, S, P or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V or a combination thereof; Q is Ti, Mo, Mn or a combination thereof; T is Cr, V, Fe, Sc, Y or a combination thereof; J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

Of course, a compound having a coating layer on the surface of the compound may be used, or a mixture of the compound and a compound having a coating layer may be used. The coating layer is a coating element compound, and may include oxide, hydroxide, oxyhydroxide of the coating element, oxycarbonate of the coating element, or hydroxycarbonate of the coating element. The compound constituting these coating layers may be amorphous or crystalline. As the coating element included in the coating layer, Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or a mixture thereof may be used. In the coating layer forming process, any coating method may be used as long as it can be coated by a method that does not adversely affect the physical properties of the positive electrode active material by using these elements in the compound, for example, spray coating, dipping, etc. Since it is a content that can be well understood by those engaged in the field, a detailed description will be omitted.

The positive active material may include 20 to 99% by weight, more preferably 30 to 95% by weight of the total weight of the composition. In addition, the average particle diameter may be 0.001 to 50 μm, more preferably 0.01 to 20 μm, but is not limited thereto.

The binder well adheres the positive active material particles to each other, and also serves to fix the positive active material to the current collector. It can be used without limitation as long as it is conventionally used in the relevant field, and representative examples include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, and ethylene oxide. Polymer, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, etc. Alternatively, two or more types may be mixed and used, but the present invention is not limited thereto. Although not limited, the content of the binder may be 0.1 to 20% by weight, more preferably 1 to 10% by weight of the total weight. In the above range, an amount sufficient to serve as a binder is not limited thereto.

The solvent may be any one or a mixed solvent of two or more selected from N-methyl pyrrolidone, acetone, and water, and is not limited thereto, and may be used as long as it is commonly used in the art. The content of the solvent is not limited, and may be used without limitation as long as the amount is sufficient to be applied on the positive electrode current collector in a slurry state.

In addition, the positive electrode active material composition may further include a conductive material.

The conductive material is used to impart conductivity to the electrode, and may be used without limitation as long as it does not cause a chemical change in the configured battery and is an electronically conductive material. Specifically, for example, natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon nanotubes, carbon-based materials such as carbon fibers; metal-based substances such as metal powders such as copper, nickel, aluminum, and silver, or metal fibers; conductive polymers such as polyphenylene derivatives; Alternatively, a conductive material including a mixture thereof may be used, and may be used alone or in combination of two or more.

The content of the conductive material may be 0.1 to 20% by weight, more specifically 0.5 to 10% by weight, and more specifically 1 to 5% by weight of the cathode active material composition, but is not limited thereto. In addition, the average particle diameter of the conductive material may be 0.001 ~ 1000 ㎛, more specifically 0.01 ~ 100 ㎛, but is not limited thereto.

The first gel polymer electrolyte includes a solvent, a dissociable salt, and a polymer matrix including any one or two or more selected from the group consisting of linear polymers and crosslinked polymers.

In the case of the linear polymer, it may be gelled and integrated by a gelation process after application, and the crosslinked polymer may be cured and integrated by a crosslinking process after application. When both the linear polymer and the cross-linked polymer are used, they are gelled and cured by a gelation process and a cross-linking process after application to form a polymer matrix having a semi-IPN structure and may be integrated. For this, one aspect of each will be described as follows.

First, in an aspect of the first gel polymer electrolyte, in the case of a cross-linked polymer matrix, any one or two or more monomers selected from the group consisting of cross-linkable monomers and derivatives thereof, an initiator, and a liquid electrolyte. A gel polymer electrolyte composition comprising: Since the liquid electrolyte and the like may be uniformly distributed in the polymer matrix in the form of a net by coating on the anode and cross-linking by applying ultraviolet radiation or heat, the solvent evaporation process may be unnecessary.

The gel polymer electrolyte composed of the cross-linked polymer matrix may be one in which a liquid electrolyte, a cross-linkable monomer, and a derivative thereof are optically cross-linked or thermally cross-linked by an initiator to form a cross-linked polymer matrix. By crosslinking, the mechanical strength and structural stability of the gel polymer electrolyte layer are improved, and when combined with the positive electrode of the above-described embodiment, the structural stability of the interface between the gel polymer electrolyte layer and the positive electrode can be further improved.

The first gel polymer electrolyte composition preferably has a viscosity suitable for the coating process, and specifically, for example, a viscosity measured using a Brookfield viscometer at 25° C. is 0.1 to 10,000,000 cps, more preferably 1.0 to 1,000,000 cps, More preferably, it may be from 1.0 to 100,000 cps, and since it is a viscosity suitable for application to a coating process in the above range, it is preferable, but is not limited thereto.

The first gel polymer electrolyte composition may include 1 to 50% by weight of a crosslinkable monomer, specifically 2 to 40% by weight, of 100% by weight of the total composition, but is not limited thereto. The initiator may be included in an amount of 0.01 to 50% by weight, specifically 0.01 to 20% by weight, more specifically 0.1 to 10% by weight, but is not limited thereto. The liquid electrolyte may be included in an amount of 1 to 95% by weight, specifically 1 to 90% by weight, more specifically 2 to 80% by weight, but is not limited thereto.

The crosslinkable monomer may be a monomer having two or more functional groups or a mixture of a monomer having two or more functional groups and a monomer having one functional group, and any monomer capable of photocrosslinking or thermal crosslinking may be used without limitation. .

Specifically, as the monomer having two or more functional groups, for example, ethylene glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate, trimethylolpropane ethoxylate It may be any one or a mixture of two or more selected from triacrylate, trimethylolpropane ethoxylate trimethacrylate, bisphenol ethoxylate diacrylate, bisphenol ethoxylate dimethacrylate, and the like.

In addition, as the monomer having one functional group, methyl methacrylate, ethyl methacrylate, butyl methacrylate, methyl acrylate, butyl acrylate, ethylene glycol methyl ether acrylate, ethylene glycol methyl ether methacrylate, acrylo It may be any one or a mixture of two or more selected from nitrile, vinyl acetate, vinyl chloride and vinyl fluoride.

In addition, an initiator may be used for photocrosslinking or thermal crosslinking of the monomer. As the initiator, any photoinitiator or thermal initiator commonly used in the art may be used without limitation.

The liquid electrolyte may include a dissociable salt and a solvent.

The dissociable salt is not limited, but specifically, for example, lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium hexafluoroantimonate (LiSbF ₆ ), lithium hexafluoroacetate (LiAsF ₆ ), lithium difluoromethanesulfonate (LiC ₄ F ₉ SO ₃ ), lithium perchlorate (LiClO ₄ ), lithium aluminate (LiAlO ₂ ), lithium tetrachloroaluminate (LiAlCl ₄ ), lithium chloride (LiCl) , lithium iodide (LiI), lithium bisoxalatoborate (LiB(C ₂ O ₄ ) ₂ ), lithium difluorooxalatoborate (LiB(C ₂ O ₄ )F ₂ ), lithium bisfluorosulfonylimide (LiFSI), lithium trifluoromethanesulfonylimide (LiN(C _x F _2x+1 SO ₂ )(C _y F _2y+1 SO ₂ ), where x and y are natural numbers) and derivatives thereof The concentration of the dissociable salt may be 0.1 to 10.0 M, more specifically, 1 to 5 M, but is not limited thereto.

The solvent is selected from organic solvents such as carbonate solvents, nitrile solvents, ester solvents, ether solvents, ketone solvents, glyme solvents, alcohol solvents, propionate solvents and aprotic solvents and water One or two or more mixed solvents may be used.

Another aspect of the first gel polymer electrolyte may be a semi-interpenetrating network (semi-IPN) structure by further including a linear polymer in a crosslinked polymer matrix. In this case, the positive electrode-electrolyte combination may further improve mechanical strength and structural stability, and further improve the structural stability of the positive electrode interface.

The linear polymer may be used without limitation as long as it is a polymer that can be impregnated with a solvent. Specifically, for example, polyvinylidene fluoride (Poly (vinylidene fluoride), PVdF), polyvinylidene fluoride hexafluoropropylene (Poy (vinylidene fluoride)-co-hexafluoropropylene, PVdF-co-HFP), polymethyl Any one selected from methacrylate (Polymethylmethacryalte, PMMA), polystyrene (PS), polyvinylacetate (PVA), polyacrylonitrile (PAN) and polyethylene oxide (PEO) It may be a combination of two or more, but is not necessarily limited thereto.

The linear polymer may be included in an amount of 1 to 90 wt% based on the weight of the crosslinked polymer matrix. Specifically, it may be included in an amount of 1 to 80% by weight, 1 to 70% by weight, 1 to 60% by weight, 1 to 50% by weight, 1 to 40% by weight, 1 to 30% by weight. That is, when the polymer matrix has a semi-IPN structure, the crosslinkable polymer and the linear polymer may be included in a weight ratio of 99:1 to 10:90. When the linear polymer is included in the above range, the crosslinked polymer matrix may secure flexibility while maintaining appropriate mechanical strength. Accordingly, when applied to a flexible battery, it is possible to realize stable battery performance even when the shape is deformed by various external forces, and it is possible to suppress the risk of battery ignition and explosion that may be caused by the shape deformation of the battery.

Another aspect of the first gel polymer electrolyte may be formed of a linear polymer matrix gelled by applying and gelling a gel polymer electrolyte composition including a linear polymer and a liquid electrolyte. Specifically, for example, a gel polymer electrolyte composition including a linear polymer, a solvent, and a dissociable salt is applied on the positive electrode active material layer, and may be physically crosslinked to form a gel. By the gelation, the mechanical strength and structural stability of the positive electrode-electrolyte assembly may be improved, and the structural stability of the positive electrode interface may be improved. At this time, since the linear polymer and the liquid electrolyte are the same as described above, redundant descriptions will be omitted. In one aspect, of the total 100% by weight of the composition including the linear polymer, the salt and the solvent, the linear polymer may be included in 1 to 50% by weight, preferably 1 to 30% by weight. and is not limited thereto. In addition, the solvent may be included in an amount of 1 to 99% by weight, preferably 8 to 60% by weight, more preferably 10 to 50% by weight, but is not limited thereto. The concentration of the dissociable salt may be 0.1 to 10.0 M, more preferably 1 to 5 M, but is not limited thereto.

In addition, the first gel polymer electrolyte composition may further include inorganic particles if necessary. The inorganic particles may be coated by controlling rheological properties such as viscosity of the gel polymer electrolyte composition. The inorganic particles may be used to improve ionic conductivity and mechanical strength of the electrolyte, and may be porous particles, but is not limited thereto. For example, metal oxides, carbon oxides, carbon-based materials, organic-inorganic composites, etc. may be used, and may be used alone or in combination of two or more. More specifically, for example, SiO ₂ , Al ₂ O ₃ , TiO ₂ , BaTiO ₃ , Li ₂ O, LiF, LiOH, Li ₃ N, BaO, Na ₂ O, Li ₂ CO ₃ , CaCO ₃ , LiAlO ₂ , SrTiO ₃ , SnO ₂ , CeO ₂ , MgO, NiO, CaO, ZnO, ZrO ₂ , and SiC may be any one or a mixture of two or more selected. Although not limited, by using the inorganic particles, it is possible to improve the thermal stability of the electrochemical device because it has high affinity with the organic solvent and is also very thermally stable.

The average diameter of the inorganic particles is not limited, but may be 0.001 μm to 10 μm. Specifically, it may be 0.1 to 10 μm, more specifically 0.1 to 5 μm. When the average diameter of the inorganic particles satisfies the above range, excellent mechanical strength and stability of the electrochemical device can be realized.

The content of the inorganic particles in the first gel polymer electrolyte composition may be 0.1 to 50% by weight, more specifically 0.1 to 40% by weight, more specifically 0.1 to 30% by weight, and the above-described viscosity range 0.1 to 10,000,000 cps, more preferably 1.0 to 1,000,000 cps, more preferably, may be used in an amount that satisfies 1.0 to 100,000 cps, but is not limited thereto.

In addition, the first gel polymer electrolyte composition may further include a performance enhancer if necessary. Non-limiting examples of the performance enhancer include any one or a mixture of two or more selected from the group consisting of a high voltage stability improver, a high temperature stability improver, an electrolyte wettability improver, an interfacial stabilizer, a gas generation inhibitor, an electrode adhesion enhancer, an anion stabilizer, and the like. it could be

Non-limiting examples of the high voltage stability improver include prop-1-ene-1,3-sultone, propane sultone, butane sultone, ethylene sulfate, ethylene propylene sulfate, trimethylene sulfate, vinyl sulfone, methyl sulfone, phenyl sulfone, Benzyl sulfone, tetramethylene sulfone, butadiene sulfone, benzoyl peroxide, lauroyl peroxide, 2-methyl maleic anhydride, succinonitrile, glutarnitrile, adiponitrile, pimelonitrile, suberonitrile, sebaconitrile, Any one or a mixture of two or more selected from azeleic dinitrile, butylamine, N,N-dicyclohexylcarbodiamine, N,N-dimethyl amino trimethyl silane, N,N-dimethylacetamide, sulfolane and propylene carbonate it could be

Non-limiting examples of the high temperature stability improver include propane sultone, propene sultone, dimethyl sulfone, diphenyl sulfone, divinyl sulfone, methane sulfonic acid, propylene sulfone, 3-fluorotoluene, 2,5-dichlorotoluene, 2- Fluorobiphenyl, dicyanobutene, tris(-trimethyl-silyl)-phosphite, vinyl ethylene carbonate, 1,3,6-hexane-tri-cyanide, 1,2,6-hexane-tri-cyanide, pyridine , 4-ethyl pyridine, 4-acetyl pyridine, 3-cyano pyridine, etc. may be any one or a mixture of two or more selected.

Non-limiting examples of the electrolyte wettability improver include lithium bis (fluorosulfonyl) imide, lithium bis (trifluoromethylsulfonyl) imide, maleic acid, tannic acid, silicon oxide, aluminum oxide, zirconia oxide, titanium It may be any one selected from oxide, zinc oxide, manganese oxide, magnesium oxide, calcium oxide, iron oxide, barium oxide, molybdenum oxide, ruthenium oxide and zeolite, or a mixture of two or more.

Non-limiting examples of the interface stabilizer include vinylene carbonate, vinylethylene carbonate, methyleneethylene carbonate, methylenemethylethylene carbonate, fluoroethylene carbonate, allyltrimethoxysilane, allyltriethoxysilane, cyclohexyltrimethoxy Silane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-gly Cydoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylethoxydimethylsilane, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol di Glycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, allyl glycidyl ether, phenyl glycidyl ether, fluoro γ-butyrolactone , difluoro γ-butyrolactone, chloro γ-butyrolactone, dichloro-butyrolactone, bromo γ-butyrolactone, dibromo γ-butyrolactone, nitro γ-butyrolactone, cyano γ -It may be any one or a mixture of two or more selected from butyrolactone and molybdenum sulfide.

Non-limiting examples of the gas generation inhibitor include diphenyl sulfone, divinyl sulfone, vinyl sulfone, phenyl sulfone, benzyl sulfone, tetramethylene sulfone, butadiene sulfone, diethylene glycol diacrylate, diethylene glycol dimethacrylate, Ethylene glycol dimethacrylate, dipropylene glycol diacrylate, dipropylene glycol dimethacrylate, ethylene glycol divinyl ether, ethoxylated trimethylolpropane triacrylate, diethylene glycol divinyl ether, triethylene glycol di Methacrylate, difetaerythritol pentaacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, propoxylated (3) trimethylolpropane triacrylate, propoxylated (6) trimethyl It may be any one or a mixture of two or more selected from allpropane triacrylate and polyethylene glycol diacrylate.

Non-limiting examples of the electrode adhesion enhancer include acetonitrile, thiopheneacetonitrile, methoxyphenylacetonitrile, fluorophenylacetonitrile, acrylonitrile, methoxyacrylonitrile and ethoxyacryl It may be any one or a mixture of two or more selected from lonitrile and the like.

A non-limiting example of the anion stabilizer may be any one or a mixture of two or more selected from dimethyl sulfone, sulfolane, and benzimidazole.

<Separator 20>

In the first aspect of the present invention, the separator 20 may have substantially the same size as the positive electrode or may be larger than the positive electrode. When the size of the separator 20 is substantially the same as that of the anode 10, it can be punched out at the same time in a stacked state of the cathode and the separator to produce a desired shape. Manufacture can be simplified since they can be accommodated simultaneously on the protrusion.

In addition, the separator 20 may be laminated to serve as a protective film when the positive electrode 10 is manufactured, and may be punched out and used in a stacked state together with the positive electrode 10 . Accordingly, one surface of the separator facing the positive electrode may be partially embedded or impregnated with the first gel polymer electrolyte integrated into the positive electrode. In addition, the second gel polymer electrolyte coated or injected on the negative electrode current collector may be partially buried or impregnated on the opposite surface facing the positive electrode.

The separator 20 may be used without limitation as long as it is generally used in an electrochemical device. For example, it may be a woven fabric, a non-woven fabric, and a porous membrane. Also, they may be a multilayer film in which one layer or two or more are laminated. The material of the separator is not limited, but specifically, for example, polyethylene, polypropylene, polybutylene, polypentene, polymethylpentene, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyamide, polycarbonate, polyimide , polyether sulfone, polyphenylene oxide, polyphenylene sulfide, polyethylene naphthalene, may be formed of any one or a mixture of two or more selected from the group consisting of copolymers thereof. In addition, the thickness is not limited, and may be in the range of 1 to 1000 μm, more specifically 10 to 800 μm, which is typically used in the art, but is not limited thereto.

In addition, the separator 20 may be a gel polymer electrolyte integrated. More specifically, the third gel polymer electrolyte may be applied to the woven fabric, the nonwoven fabric and the porous membrane to include the electrolyte. The separator may be used in the form of a separator-electrolyte combination from the viewpoint of improving mechanical strength, and may be for further improving ionic conductivity. At this time, the application may be performed using not only a coating method such as bar coating, spin coating, slot die coating, dip coating, etc., but also an injection method.

Since the third gel polymer electrolyte is the same as that described above in the first gel polymer electrolyte, a redundant description will be omitted. In this case, the third gel polymer electrolyte may be the same as or different from the first gel polymer electrolyte used in the positive electrode described above or the second gel polymer electrolyte to be described later.

In addition, when used as a protective film of the positive electrode, the first gel polymer electrolyte applied to the positive electrode or a part of the second gel polymer electrolyte to be described later may be buried and formed.

<Cathode current collector (30)>

In the first aspect of the present invention, the negative electrode current collector 30 is made of only a current collector. Accordingly, it is possible to provide a flexible battery while minimizing the thickness of the battery.

The negative electrode current collector 30 may be selected from the group consisting of a thin film form, a form in which a thin film or mesh current collector is laminated on one or both sides of a conductive substrate, and a metal-mesh composite. The metal-mesh composite is integrated by heat-compressing the thin-film metal and the mesh-like metal or polymer material to integrate the thin film between the holes of the mesh, so that the metal does not break or crack even when bent. As described above, when the metal-mesh composite is used, it is more preferable to prevent cracks from occurring in the current collector during bending of the battery or during charging and discharging, but is not limited thereto. The material may be made of a metal or polymer such as lithium metal, aluminum, aluminum alloy, tin, tin alloy, zinc, zinc alloy, lithium aluminum alloy and other lithium metal alloy, or a composite thereof.

The negative electrode current collector 30 may be used without limitation as long as it is a substrate having excellent conductivity used in the art. Specifically, for example, it may be made of one including any one selected from a conductive metal, a conductive metal oxide, and the like. In addition, the current collector may be in a form in which the entire substrate is made of a conductive material, or a conductive metal, a conductive metal oxide, a conductive polymer, or the like is coated on one or both surfaces of the insulating substrate. In addition, the current collector may be made of a flexible substrate, and can be easily bent to provide a flexible electronic device. In addition, it may be made of a material having a restoring force that returns to its original shape after being bent. More specifically, for example, the current collector may include aluminum, zinc, silver, tin, tin oxide, stainless steel, copper, nickel, iron, lithium, cobalt, titanium, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and It may be made of a complex thereof, and the like, but is not limited thereto. More preferably, it may be any one or a combination of two or more selected from the group consisting of aluminum, stainless steel, copper, nickel and titanium.

In one aspect, the negative electrode current collector is a laminate including a first negative electrode metal layer and a second negative electrode metal layer, and the first negative electrode metal layer is any one selected from the group consisting of copper, nickel and stainless steel, or a combination of two or more. , the second anode metal layer may be any one or a combination of two or more selected from the group consisting of aluminum, stainless steel, copper, nickel and titanium, wherein the first cathode metal layer and the second anode metal layer may have different compositions. .

The thickness of the negative electrode current collector 30 may be 1 to 500 μm, more specifically, 1 to 200 μm, but is not limited thereto.

In addition, although not shown, the negative electrode current collector may further include a terminal portion extending further than the outer end of the first partition wall 41 . As described above in the description of the upper sheet, the negative electrode current collector 30 may further include a terminal portion extending further in the surface direction than the outer end of the first partition wall 41 . In this case, the terminal part may be a further extension of the anode current collector 30 or a further connection of a separate metal layer to the anode current collector 30 .

<First bulkhead 41 and second bulkhead 42>

In the first aspect of the present invention, the shape of the partition walls 41 and 42 is not limited, and the shape of the battery may be determined according to the external shape of the partition wall. That is, if the external shape of the barrier rib is circular, the shape of the negative electrode current collector, the first separator, and the upper sheet may also be circular. In addition, the shape of the anode and the separator may be determined according to the shape of the inside of the partition wall. That is, if the inside of the partition wall is circular, the shape of the anode and the separator accommodated may also be circular. In addition, the shape of the outside of the partition wall may be a square shape, but the shape inside the partition wall may be a circular shape. That is, the negative electrode current collector, the first separator, and the upper sheet may have a rectangular shape, and the positive electrode and the separator may have a circular shape.

The partition walls 41 and 42 may be made of a polymer material that can be fused and sealed by heat. The partition wall may be melt-sealed by thermal compression using a heating plate or a heating roller. Since the material of the partition wall is the same as that described for the upper sheet sealing layer, further description thereof will be omitted.

A position at which the first partition wall 41 is formed may be formed along the periphery 31 of the upper surface of the negative electrode current collector, and may be formed to extend further inward than the second partition wall 42 . The position at which the second barrier rib 42 is formed may be substantially the same as the position at which the first barrier rib 41 is formed. can do.

Although not limited, specifically, for example, within 0.1 to 2 mm from the edge of the anode, more preferably, it may be formed in a portion spaced apart from 0.5 to 1 mm. By having such a spaced distance, a space portion may be formed between the anode and the second partition wall 42 . In addition, it may be advantageous to provide a flexible battery by having such a spaced distance.

The first partition wall 41 is formed on the periphery 31 of the upper surface of the negative electrode current collector, and includes a second partition wall 42 on the first partition wall that is in close contact with the upper sheet to be sealed, The inner surface of the barrier rib protrudes inward than the inner surface of the second barrier rib to form an inner protrusion 411, and the anode and the separator are accommodated in a space formed by sealing the second barrier rib and the upper sheet, The peripheral portion 211 of the lower surface of the separation membrane 20 is in close contact with the upper surface of the protruding portion 411 of the first partition wall.

The thickness of the first partition wall 41 is not limited, but may be 1 to 100 μm, preferably 5 to 75 μm, and more preferably 10 to 50 μm. The thickness of the second partition wall 42 is not limited, but may be 10 to 400 μm, preferably 25 to 300 μm, and more preferably 40 to 250 μm. The size of the inner protrusion 411 is not limited, but may be 0.1 to 10 mm, preferably 0.5 to 7.5 mm, and more preferably 1 to 5 mm.

In addition, the first partition wall 41 and the second partition wall 42 may further include an adhesive layer for more firmly bonding between the upper sheet, the negative electrode current collector, and the partition wall, if necessary. The adhesive layer may be used without limitation as long as it is conventionally used in the relevant field. Specifically, for example, an acrylic adhesive, an epoxy adhesive, a cellulose adhesive, etc. may be used, but the present invention is not limited thereto. The thickness of the adhesive layer may be specifically, for example, 0.1 to 100 μm, more specifically 1 to 50 μm, but is not limited thereto.

In addition, a lithium metal layer 60 integrated with the negative electrode current collector and a second gel polymer electrolyte (not shown) may be included between the negative electrode current collector and the separator inside the first partition wall.

The second gel polymer electrolyte may be formed by application or injection, and application refers to a coating method such as bar coating, spin coating, slot die coating, and dip coating. Specifically, after forming the first barrier rib on the negative electrode current collector, the second gel polymer electrolyte may be formed by coating or injecting a second gel polymer electrolyte into the space formed by the first barrier rib.

Since the second gel polymer electrolyte is the same as described for the first gel polymer electrolyte, a redundant description will be omitted. In this case, the second gel polymer electrolyte may be the same as or different from the first gel polymer electrolyte used in the positive electrode.

The first gel polymer electrolyte and the second gel polymer electrolyte may include a solvent and a dissociable salt, and may consist of a polymer matrix further comprising any one or two or more selected from the group consisting of linear polymers and crosslinked polymers. In addition, if necessary, it may further include a performance enhancing agent. Therefore, the "different" means that it can be made of different compositions. Specifically, the first gel polymer electrolyte and the second gel polymer electrolyte may include a type of solvent; the type or concentration of the dissociable salt; linear polymer type or content; crosslinked polymer type or content; the type or concentration of the performance enhancer; At least one of them may be different.

More specifically, the ionic conductivity IC ₁ of the first gel polymer electrolyte and the ionic conductivity IC ₂ of the second gel polymer electrolyte may satisfy Equation 1 below.

[Formula 1]

IC ₁ - IC ₂ ≥ 0.1 mS/cm

When the difference in ionic conductivity is 0.1 mS/cm or more, charge/discharge efficiency and battery life are increased, and high battery safety can be secured at the same time.

In one embodiment, the first and second gel polymer electrolyte compositions may have different ionic conductivity.

In one embodiment, the first and second gel polymer electrolyte compositions may have a difference in ionic conductivity of 0.1 mS/cm or more. The upper limit is not limited, but specifically, for example, may be 0.1 to 100 mS/cm.

The ionic conductivity may be calculated as follows.

[Formula 1]

IC ₁ = (τ _cathode ² × IC _cathode )/P _cathode

[Formula 2]

IC ₂ = (τ _anode ² × IC _anode )/P _anode

In this case, IC ₁ and IC ₂ are the ionic conductivities of the first electrolyte and the second electrolyte, respectively, and IC _cathode , IC _anode , and IC _separator are the ionic conductivity of the positive electrode-electrolyte composite, the negative electrode-electrolyte composite, and the separator-electrolyte composite, respectively. , τ _cathode , τ _anode , and τ _separator are the curvatures of the anode, cathode, and separator, respectively, and P _cathode , _Panode , and P _separator mean the porosity of the anode, cathode, and separator.

In order to calculate the ionic conductivity of the electrolyte, the porosity (vol%) of the specimen may be measured using a mercury pressure porosimeter for each of the positive electrode, the negative electrode, and the separator. A standard electrolyte with known ionic conductivity (in this patent, a liquid electrolyte in _{which 1 mol of LiPF 6} is dissolved in a solvent mixed with 50% by volume of ethylene carbonate and 50% by volume of ethyl methyl carbonate as a standard electrolyte was used.) The ionic conductivity of the positive electrode-electrolyte assembly, the negative electrode-electrolyte assembly, and the separator-electrolyte assembly is measured, and the curvature of the positive electrode, the negative electrode, and the separator can be calculated through the above formula.

The ionic conductivity is measured by cutting the positive electrode-electrolyte composite, the negative electrode-electrolyte composite, and the separator-electrolyte composite into a circle with a diameter of 18 mm and each coin cell 2032 is prepared, and then measured using an AC impedance measurement method depending on the temperature. can The ionic conductivity was measured in a frequency band of 1 MHz to 0.01 Hz using a VMP3 measuring device.

In the case of an electrochemical device containing any electrolyte, the seal is removed, the anode-electrolyte complex, the cathode-electrolyte complex, and the separator-electrolyte complex are separated, and each binder is placed in a dimethyl carbonate solvent and stored for 24 hours, and then stored in an acetone solvent After 24 hours of storage in a dimethyl carbonate solvent, and 24 hours of storage in a dimethyl carbonate solvent, the electrolyte in each binder was removed, and then dried in a vacuum atmosphere for 24 hours (At this time, the positive electrode and the negative electrode from which the electrolyte was removed were 130 degrees, and the separator was 60 It was dried at the same temperature). The positive electrode, the negative electrode and the separator from which the electrolyte has been removed are calculated using the porosity and the standard electrolyte in the above-mentioned method, and the degree of curvature is calculated, and the positive electrode-electrolyte assembly, the negative electrode-electrolyte assembly and the separator in the state before removing the electrolyte- By measuring the ionic conductivity of the electrolyte binder, it is possible to measure the ionic conductivity of the first electrolyte and the second electrolyte through the above formula.

Hereinafter, a Nyquist plot obtained by measuring the ionic conductivity of the positive electrode-electrolyte composite, the negative electrode-electrolyte composite, and the separator-electrolyte composite will be described in detail. The positive electrode-electrolyte composite and the negative electrode-electrolyte composite are composite conductors and are an electron conductor and an ion conductor, and the Nyquist plot for this shows the shape of a semicircle. In this case, the semi-circle is _{divided into a high-frequency region resistance (R 1} ) and a low-frequency region resistance (R ₂ ), and the resistance to ion conduction can be calculated using the following formula.

[Formula 4]

R _ion = R ₂ - R ₁

The separation membrane-electrolyte combination is an ion conductor and represents an open shape that rises vertically in the Nyquist plot, and the impedance resistance value of the horizontal axis means resistance to ion conduction. The ionic conductivity of the anode-electrolyte complex, the cathode-electrolyte complex, and the separator-electrolyte complex is a resistance value to ion conduction obtained above, and can be calculated using the following formula.

[Formula 5]

IC = L/(R _ion × A)

In this case, L is the thickness of the specimen (thickness excluding the current collector of the positive and negative electrodes and the thickness of the separator), and A is the area of the specimen.

In one embodiment, the first and second gel polymer electrolyte compositions may have different slopes obtained from Arrhenius plots of ionic conductivity and temperature at 20 to 80°C.

In the present invention, the slope of the Arrhenius plot is the ion conductivity data for each temperature obtained above, with the inverse 1/T of the temperature T(K) on the abscissa and the logarithm of ion conductivity ln(IC) on the ordinate in the graph, respectively, It can be obtained from the slope of the straight line at 20 ~ 80 °C.

In the present invention, the type of the solvent of the first gel polymer electrolyte and the second gel polymer electrolyte; the type or concentration of the dissociable salt; linear polymer type or content; crosslinked polymer type or content; the type or concentration of the performance enhancer; At least one of the differences may be confirmed by methods such as infrared spectroscopy, X-ray photoelectron analysis, inductively coupled plasma mass spectrometry, nuclear magnetic resonance spectroscopy, and time-of-flight secondary ion mass spectrometry.

More specifically, the infrared spectroscopic analysis separates the anode, cathode, and separator from the electrode assembly in the state where the charging/discharging current is applied and the initial formation process is completed, and each Fourier transform infrared spectroscopy (equipment name: 670-) IR, equipment manufacturer: Varian). From the absorption spectrum obtained by spectroscopy of the reflected light when irradiated with infrared rays, the peak intensity derived from the material characteristics of different solvent types, salt types, and salt concentrations can be discriminated and judged.

X-ray photoelectron analysis is performed by separating the anode, cathode, and separator from the electrode assembly in the state where the charging/discharging current is applied and the initial formation process is completed, and each X-ray photoelectron spectroscopy (X-ray Photoelectron Spectroscopy, equipment name: K-Alpha, equipment) Manufacturer: Thermo Fisher). From the energy of the photoelectrons escaped by the X-rays irradiated to the sample, the presence or absence of elements contained in different solvents and salts and the state of chemical bonding can be discriminated.

Inductively Coupled Plasma Mass Spectrometry (Inductively Coupled Plasma Mass Spectromerty, equipment name: ELAN DRC-) separates the anode, cathode, and separator from the electrode assembly in the state where the charging/discharging current is applied and the initial formation process is completed. II, equipment manufacturer: Perkin Elmer). By ionizing the salt contained in the sample and separating the ions using a mass spectrometer, different solvent types, salt types, and salt concentrations can be distinguished and judged.

Nuclear magnetic resonance spectroscopy (NMR) is a two-dimensional nuclear magnetic resonance spectroscopy (NMR) analysis (equipment name: AVANCE III) by separating the anode, cathode, and separator from the electrode assembly in the state where the charging/discharging current is applied and the initial formation process is completed. HD, equipment manufacturer: Bruker). Using the nuclear magnetic resonance phenomenon of atomic nuclei, which occurs when a magnetic field is applied to the performance enhancer included in the sample, information about the chemical environment around the nucleus and spin bonds with neighboring atoms can be used to determine the types of different solvents, types of salts, and salts. Concentrations can be differentiated.

Time-of-flight secondary ion mass spectrometry is a time-of-flight secondary ion mass analysis (Time-of-flight Secondary Ion Mass) by separating the anode, cathode, and separator from the electrode assembly in the state where the charging and discharging current is applied and the initial formation process is completed. Spectrometry, equipment name: TOF-SIMS 5, equipment manufacturer: ION TOF). Through mass spectrometry of secondary ions generated in the sample, it can be determined by distinguishing different types of solvents, types of salts, and concentrations of salts.

<Lithium metal layer 60>

In the first aspect of the present invention, the lithium metal layer 60 may be formed by initial charging after the battery is manufactured, and may be formed integrally on the negative electrode current collector. In addition, the lithium metal layer 60 may be formed in a space formed as the first partition wall 41 on the negative electrode current collector 30 protrudes inward and comes in close contact with the separator 20 as shown in FIG. 1 . Accordingly, it is possible to solve the problem that the lithium metal layer is formed in excess and is electrically connected to the positive electrode to cause a short circuit. In addition, it is possible to prevent a short circuit due to the burr of the peripheral portion when using the battery, thereby further improving the stability of the electrochemical device.

The lithium metal layer may be a porous lithium metal layer, more specifically, a porous dense flat structure.

In the present invention, the porous dense flat structure means a lithium metal layer formed by the first charging after the battery is manufactured as described above. As shown in FIG. 6 of the present invention, the battery of the present invention uses a gel polymer electrolyte. As a result, it has a dense flat structure and has porosity that is distinct from metal foil.

As shown in FIG. 7 , the dense flat structure means that the lithium metal layer is formed in a more dense and flat structure compared to the lithium metal layer formed on the negative electrode current collector when a liquid electrolyte is used.

In one aspect of the present invention, the thickness of the lithium metal layer may be 1 to 100 μm, but is not limited thereto.

<Lower seat (70)>

The first aspect of the present invention may further include a lower sheet 70 as necessary as shown in FIG. 6 .

The lower sheet 70 may be closely adhered to the negative electrode current collector, and an opening 71 may be formed in a portion of the lower sheet to expose a portion of the negative electrode current collector to the outside.

One aspect of the lower sheet 70 may include an insulating layer. By including the insulating layer, it is possible to protect the anode current collector from external materials and to electrically insulate it from the outside. In this case, the insulating layer may have a portion of the anode current collector exposed to the outside, including a groove in which the insulating layer is not formed because the insulating layer is partially opened.

Another aspect of the lower sheet 70 may be a laminate including a barrier layer and a sealing layer. In addition, if necessary, it may further include a substrate layer on the barrier layer. In this case, a portion of the laminate may be opened so that a portion of the negative electrode current collector including a groove in which the laminate is not formed is exposed to the outside. Since the barrier layer, the sealing layer, and the base layer are the same as those described in the upper sheet, further descriptions will be omitted.

<The manufacturing method of the first aspect>

The manufacturing method of the thin lithium battery of the first aspect is

(S1) preparing a positive electrode-electrolyte assembly including a first gel polymer electrolyte by applying and gelling the first gel polymer electrolyte composition on the positive electrode;

(S2) preparing a separation membrane;

(S3) cutting the positive electrode-electrolyte assembly and the separator;

(S4) laminating a first barrier rib sheet having a barrier rib pattern partitioned into a cell region having one or a plurality of openings on an upper surface of the anode current collector;

(S5) laminating a second partition wall sheet having a larger opening than that of the first partition wall sheet on the first partition wall sheet;

(S6) forming a second gel polymer electrolyte on the negative electrode current collector by injecting and gelling a second gel polymer electrolyte composition into each of one or a plurality of cell regions of the first partition wall sheet;

(S7) arranging a separator and a positive electrode-electrolyte assembly in each of one or a plurality of cell regions of the second barrier rib sheet to form a structure in which a negative electrode current collector, a separator, and a positive electrode-electrolyte assembly are stacked;

(S8) laminating an upper sheet on the laminated structure; and

(S9) charging one or a plurality of cells;

includes

In this case, the first partition wall sheet used in step (S4) is formed to have a larger width to protrude inward compared to the second partition wall sheet used in (S5).

In one aspect, in the step (S1), the positive electrode means a laminate in which a positive electrode active material layer including a lithium composite oxide is formed on a positive electrode current collector. That is, by coating the first gel polymer electrolyte composition on the positive electrode active material layer, the positive electrode active material layer and the first gel polymer electrolyte are integrated to prepare a positive electrode-electrolyte combination.

At this time, the first gel polymer electrolyte composition may be composed of three aspects as follows. i) linear polymers, solvents and dissociable salts. In addition, if necessary, it may further include a performance enhancing agent. ii) crosslinkable monomers, solvents and dissociable salts. In addition, if necessary, it may further include a performance enhancing agent. iii) linear polymers, crosslinkable monomers, solvents and dissociable salts. In addition, if necessary, it may further include a performance enhancing agent.

Aspect i) may be gelled after application and then gelled to form a gel polymer electrolyte including a linear polymer matrix, a solvent, and a dissociable salt.

In addition, in the ii) embodiment, the gel polymer electrolyte including a crosslinked polymer matrix, a solvent, and a dissociable salt may be formed by curing and gelling after a curing process after application.

In addition, the iii) aspect is cured and gelled after the curing process and gelation process after application to form a gel polymer electrolyte comprising a polymer matrix having a semi-interpenetrating network (semi-IPN) structure, a solvent, and a dissociable salt. there is.

In the step (S1), the application includes coating methods such as bar coating, spin coating, slot die coating, and dip coating of the composition, as well as inkjet printing, gravure printing, gravure offset, aerosol printing, stencil printing and screen printing. It may be coated by a printing method. In addition, as described above, by using a linear polymer or a cross-linking monomer, it is gelled or cured to form a linear polymer matrix, a cross-linked polymer matrix, or a polymer matrix having a semi-interpenetrating network (semi-IPN) structure. In addition, if necessary, it may further include a performance enhancing agent.

In the step (S2), applying and gelling a gel polymer electrolyte composition on the separator to prepare a separator-electrolyte complex including a gel polymer electrolyte; may include.

In the step (S3), each of the positive electrode-electrolyte binder and the separator is cut when cutting. Cutting may be performed by laser cutting, punching, etc., but is not limited thereto. Alternatively, the cutting may be performed at one time in a state in which the separator is laminated on the positive electrode-electrolyte assembly. That is, the separator may be cut together in an attached state to serve as a protective film of the positive electrode-electrolyte assembly. In this case, the separator may be one in which the first gel polymer electrolyte composition applied to the positive electrode-electrolyte assembly is imbedded.

The step (S4) is a process of forming a barrier rib pattern on the upper portion of the anode current collector, and stacking barrier rib sheets on which barrier rib patterns dividing cell regions having one or a plurality of openings are formed or forming barrier ribs while forming the anode current collector and the upper part The first barrier rib pattern may be formed by applying an adhesive composition capable of adhering to the sheet. The barrier rib pattern may be formed around an edge of the upper surface of the negative electrode current collector. The barrier rib sheet may be made of a polymer material that can be fused and sealed by heat. In addition, the cell having the plurality of openings means that two or more cell regions are formed so that several batteries can be manufactured at the same time.

The step (S5) is a step of stacking a second partition wall sheet having a larger opening than that of the first partition wall sheet on the first partition wall sheet. In the process of forming a second barrier rib pattern on an upper portion of the first barrier rib sheet, the first barrier rib 41 and The second barrier rib pattern may be formed by applying an adhesive composition capable of adhesion to the upper sheet 50 . The barrier rib sheet may be made of a polymer material that can be fused and sealed by heat.

In this case, the thickness of the second barrier rib sheet is preferably determined in consideration of the thickness for accommodating the positive electrode and the separator, and the thickness is preferably set so that the positive electrode current collector can be in close contact with the upper sheet.

In addition, the plurality of cells means that two or more cell regions are formed so that several batteries can be manufactured at the same time.

In the step (S6), the injection may be performed simply by injecting the second gel polymer electrolyte composition compared to application. At this time, since it can be formed not only by injection but also by coating, the coating method is not excluded.

In this case, the second gel polymer electrolyte composition may have the same composition as the first gel polymer electrolyte composition, and may have different compositions as needed. That is, the first gel polymer electrolyte and the second gel polymer electrolyte may include a type of solvent; the type or concentration of the dissociable salt; linear polymer type or content; cross-linked polymer type or content; the type or concentration of the performance enhancer; At least one of them may be different.

More specifically, the ionic conductivity IC ₁ of the first gel polymer electrolyte and the ionic conductivity IC ₂ of the second gel polymer electrolyte may satisfy Equation 1 below.

[Formula 1]

IC ₁ - IC ₂ ≥ 0.1 mS/cm

When the difference in ionic conductivity is 0.1 mS/cm or more, charge/discharge efficiency and battery life are increased, and high battery safety can be secured at the same time.

In step (S7), the one or a plurality of cell regions means a cell region formed in the barrier rib pattern, and by disposing the separator and the positive electrode-electrolyte assembly prepared above, the negative electrode current collector, the separator and the positive electrode-electrolyte assembly to form a stacked structure.

In the step (S8), the anode current collector and the upper sheet are adhered and sealed by laminating the upper sheet on the laminated structure and heat-compressing the upper sheet.

Next, step (S9) is a process of forming a lithium metal layer on the anode current collector by charging one or a plurality of cells. In this case, in the case of a plurality of cells, it is also possible to charge after cutting into one cell, and if necessary, it is also possible to cut and charge the required number of cells, or cut after charging.

[Second aspect of thin lithium battery]

2 is a cross-sectional view of a thin lithium battery 2000 according to a second aspect of the present invention. The remaining portion is the same as described in the first embodiment, and the lithium metal layer 61 is additionally formed on the portion where the inner protrusion 411 of the first partition wall 41 and the peripheral portion 211 of the lower surface of the separator 20 are in close contact. It may include more.

In the second aspect, the first partition wall 41 may include a polar polyolefin-based resin, and the first partition wall has a thickness of 1 to 50 μm, preferably 5 to 40 μm, more preferably 10 to 30 μm. it could be As the first partition wall 41 is formed to the above thickness while including the polar polyolefin-based resin as described above, the inner protrusion 411 of the first partition wall 41 and the peripheral portion 211 of the lower surface of the separator 20 A lithium metal layer 61 may be further included in a portion to which is in close contact. By further including the lithium metal layer 61 as described above, there is an effect of increasing the capacity per area of the unit thin lithium battery compared to the first embodiment.

The polar polyolefin-based resin may be a polyolefin resin including an acetate group, an acrylic group, an alcohol group, and a carboxylic acid group, and specifically, for example, ethylene vinyl acetate, maleic acid-grafted polyolefin-based resin, and ethylene vinyl alcohol. may be used, but is not limited thereto.

In addition, each configuration constituting the thin lithium battery of the second aspect of the present invention is the same as that described in the first aspect, and thus a redundant description is omitted.

As described above, the present invention has been described with specific details and limited examples and drawings, but these are only provided to help a more general understanding of the present invention, and the present invention is not limited to the above embodiments, and the present invention is not limited to the above embodiments. Various modifications and variations are possible from these descriptions by those of ordinary skill in the art.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and not only the claims to be described later, but also all those with equivalent or equivalent modifications to the claims will be said to belong to the scope of the spirit of the present invention. .

10: positive electrode
11: positive current collector
12: composite active material layer
21: separator
211: peripheral portion of the lower surface of the separator
22: second separator
30: negative electrode current collector
31: upper surface peripheral portion of the negative electrode current collector
41: first bulkhead
411: inner protrusion
42: second bulkhead
50: upper seat
60, 61: lithium metal layer
70: lower seat
71: open part

Claims (29)

The top sheet, the positive electrode, the separator, and the negative electrode current collector are sequentially stacked,
The positive electrode is a positive electrode-electrolyte assembly in which a positive electrode active material layer including a lithium composite oxide and a first gel polymer electrolyte are integrated on a positive electrode current collector, and the positive electrode current collector is in close contact with the upper sheet,
The separator is substantially the same size as the positive electrode or larger than the positive electrode,
The negative electrode current collector includes a first partition wall on the periphery of the upper surface,
and a second barrier rib on the upper portion of the first barrier rib to be sealed in close contact with the upper sheet,
The inner surface of the first partition wall is formed to have a larger width to protrude inward than the inner surface of the second partition wall,
The anode and the separator are accommodated in a space formed by sealing the second partition wall and the upper sheet, and the periphery of the lower surface of the separator is in close contact with the upper surface of the protruding portion of the first partition wall,
A thin lithium battery comprising a lithium metal layer integrated with the anode current collector and a second gel polymer electrolyte between the anode current collector and the separator inside the first partition wall. The method of claim 1,
The separator is a thin lithium battery in which a gel polymer electrolyte is integrated. The method of claim 1,
The first partition wall is a thin lithium battery having a thickness of 1 to 50 ㎛. 4. The method of claim 3,
The first partition wall is a thin lithium battery comprising a polar polyolefin-based resin. 5. The method of claim 4,
The thin lithium battery further comprising a lithium metal layer in a portion in which the periphery of the lower surface of the first partition wall and the separator are in close contact. The method of claim 1,
The upper sheet is formed of a metal layer, and the positive electrode current collector and the metal layer are in close contact with each other to be electrically connected to each other. 7. The method of claim 6,
The thin lithium battery further comprising at least one junction portion at a portion in which the positive electrode current collector and the metal layer are in close contact. 7. The method of claim 6,
A thin lithium battery further comprising at least one conductive layer selected from a conductive adhesive layer, a conductive adhesive layer, a conductive paste layer, and an anisotropic conductive layer between the positive electrode current collector and the metal layer. 7. The method of claim 6,
The upper sheet further includes an insulating layer on an outermost layer, and a portion of the insulating layer is open. The method of claim 1,
The upper sheet is a laminate including a barrier layer and a sealing layer,
The barrier layer is made of a metal foil or a polymer material,
The sealing layer is made of an insulating material, and is made of a material that can be adhered in close contact with the upper surface of the positive electrode current collector and the partition wall,
An open portion is formed in a portion of the upper sheet to expose a portion of the positive electrode current collector to the outside. 11. The method of claim 10,
The upper sheet may further include a base layer made of an insulating material on the barrier layer. The method of claim 1,
The lithium metal layer is a thin lithium battery having a thickness of 1 to 100 ㎛. The method of claim 1,
The lithium metal layer is a thin lithium battery having a porous dense flat structure. The method of claim 1,
The anode current collector is any one or a combination of two or more selected from the group consisting of aluminum, stainless steel, copper, nickel and titanium. The method of claim 1,
The negative electrode current collector is a laminate including a first negative electrode metal layer and a second negative electrode metal layer,
The first anode metal layer is any one or a combination of two or more selected from the group consisting of copper, nickel and stainless steel,
The second anode metal layer is any one or a combination of two or more selected from the group consisting of aluminum, stainless steel, copper, nickel and titanium,
The thin lithium battery of the first anode metal layer and the second anode metal layer having different compositions. The method of claim 1,
The anode current collector further comprises a terminal portion extending further than the outer end of the first partition wall thin lithium battery. According to any one of claims 6 to 8 selected from,
The metal layer of the upper sheet further comprises a terminal portion extending more than the outer end of the second partition wall thin lithium battery. The method of claim 1,
The positive electrode current collector is a laminate including a first positive electrode metal layer and a second positive electrode metal layer,
The first anode metal layer and the second cathode metal layer have different compositions from each other. The method of claim 1,
The first gel polymer electrolyte and the second gel polymer electrolyte include a solvent and a dissociable salt,
The first gel polymer electrolyte and the second gel polymer electrolyte are a thin lithium battery that is a polymer matrix further comprising any one or two or more selected from the group consisting of linear polymers and crosslinked polymers. 20. The method of claim 19,
The first gel polymer electrolyte is gelled after application and integrated with the positive electrode active material layer. 20. The method of claim 19,
The second gel polymer electrolyte is gelled after application or injection and distributed on the negative electrode current collector inside the first partition wall. 20. The method of claim 19,
The first gel polymer electrolyte and the second gel polymer electrolyte each have different ionic conductivity, a thin lithium battery. 23. The method of claim 22,
The ionic conductivity IC ₁ of the first gel polymer electrolyte and the ionic conductivity IC ₂ of the second gel polymer electrolyte satisfy Equation 1 below, a thin lithium battery.
[Formula 1]
IC ₁ - IC ₂ ≥ 0.1 mS/cm 20. The method of claim 19,
The first gel polymer electrolyte and the second gel polymer electrolyte may include a type of solvent; the type or concentration of the dissociable salt; linear polymer type or content; cross-linked polymer type or content; At least one of which is different, a thin lithium battery. 20. The method of claim 19,
The first gel polymer electrolyte and the second gel polymer electrolyte further include a performance enhancing agent, and the performance enhancing agent of the first gel polymer electrolyte and the second gel polymer electrolyte is different in type or concentration, a thin lithium battery. The method of claim 1,
The thin lithium battery further comprising a lower sheet adhered in close contact with the negative electrode current collector, wherein an opening is formed in a portion of the lower sheet so that a portion of the negative electrode current collector is exposed to the outside. (S1) preparing a positive electrode-electrolyte assembly including a first gel polymer electrolyte by applying and gelling a first gel polymer electrolyte composition on the positive electrode;
(S2) preparing a separation membrane;
(S3) cutting the positive electrode-electrolyte assembly and the separator;
(S4) laminating a first barrier rib sheet formed with a barrier rib pattern dividing a cell region having one or a plurality of openings on an upper surface of an anode current collector;
(S5) laminating a second partition wall sheet having a larger opening than that of the first partition wall sheet on the first partition wall sheet;
(S6) injecting and gelling a second gel polymer electrolyte composition into each of one or a plurality of cell regions of the first partition wall sheet;
(S7) arranging a separator and a positive electrode-electrolyte assembly in each of one or a plurality of cell regions of the second barrier rib sheet to form a structure in which a negative electrode current collector, a separator, and a positive electrode-electrolyte assembly are stacked;
(S8) laminating an upper sheet on the laminated structure; and
(S9) charging one or a plurality of cells;
A method of manufacturing a thin lithium battery comprising a. 28. The method of claim 27,
In the step (S2), applying and gelling a gel polymer electrolyte composition on the separator to prepare a separator-electrolyte complex including a gel polymer electrolyte;
In the steps (S3) and (S7), the separator is the separator-electrolyte combination. 28. The method of claim 27,
In the step (S9), a lithium metal layer is formed between the negative electrode current collector and the second gel polymer electrolyte by charging.

Images