KR20190024451A - Flexible battery having exterior part formed pattern - Google Patents

Abstract

According to the present invention, a flexible battery assembly comprises: an electrode assembly including at least one unit cell having a pair of electrode plates having different polarities with a separation membrane interposed therebetween, and an electrode tab protruding from each of the electrode plates and not having an electrode combination; a reinforcement tab fused and fixed on the electrode tab constituting the electrode assembly; and a pair of electrode leads welded to the reinforcement tab to be electrically connected to the electrode tab, or welded to the electrode tab in a bending state. The electrode tab includes an electrode lead connecting tab and an electrode parallel connecting tab. The electrode parallel connecting tab connects, with each other, electrode plates having the same polarity among a plurality of stacked electrode plates. One of the pair of electrode leads is connected to the electrode lead connecting tab by being welded onto a reinforcement tab having a structure of being interposed between the electrode lead connecting tab and the electrode leads. The other one of the pair of electrode leads is bent in a 180° opposite direction in a state of being welded to the electrode lead connecting tab so as to face the electrode assembly in the electrode lead connecting tab, and has a structure of facing the outside of the electrode assembly.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a flexible battery having a pattern-

The present invention relates to a flexible battery capable of preventing a crack from occurring even when bending is generated by forming a predetermined pattern on a casing formed so as to surround an electrode assembly and maintaining a capacity retention rate at a certain level or more .

A secondary battery is a battery capable of charging and discharging unlike a primary battery which can not be charged, and is widely used in high-tech electronic devices such as a cellular phone, a notebook computer, and a camcorder. [0003] As the portable electronic devices have become lighter and more sophisticated and the Internet of things (IOT) has developed, much research has been conducted on secondary batteries used as driving power sources.

Particularly, lithium secondary batteries have higher voltage and higher energy density per unit weight than nickel-cadmium batteries and nickel-hydrogen batteries, which are widely used as power sources for portable electronic equipment, and their demand is increasing.

The secondary battery is a battery using an electrochemical reaction generated between an electrolytic material and an electrode when the positive electrode and the negative electrode are connected to each other while an anode and a cathode are inserted into the electrolytic material. Unlike a conventional primary battery, Is a battery capable of recharging and recharging the energy consumed by the battery charger and used repeatedly, so that it is spreading with the popularization of wireless electric and electronic products.

Typically, a flexible laminated type electrode assembly formed by laminating a plurality of positive electrode plates and negative electrode plates with a separator interposed therebetween, in which a separation membrane is inserted between a positive electrode plate and a negative electrode plate and wound together in a helical shape, It is widely used in batteries. For example, a cylindrical battery includes a cylindrical can accommodated in a cylindrical can, and an electrolyte is injected and sealed. The prismatic type cell is formed by pressing a wound electrode assembly or a stacked electrode assembly to flatten and flatten it, . The pouch-type battery is formed by wrapping a wound electrode assembly or a stacked electrode assembly together with an electrolyte in a pouch-type sheathing material. In such an electrode assembly, the positive electrode tab and the negative electrode tab may be respectively drawn out from the positive electrode plate and the negative electrode plate to the outside of the electrode assembly and connected to the positive electrode and the negative electrode of the secondary battery.

Meanwhile, the electrode tabs are connected to the electrode leads through the plurality of positive electrode plates stacked in the vertical direction and the electrode tabs on the negative electrode plate. In the conventional joint structure between the electrode tabs and the electrode leads, the bonding force is somewhat lowered in the process of direct welding, There is a problem in coupling between the electrode tab and the electrode lead through the deformation using operation of the same battery.

For example, in a pouch-type secondary battery according to Korean Patent Laid-Open Publication No. 10-2013-0063709, a pouch type secondary battery using two electrodes, a separator, and an electrolyte in a pouch and sealing them, , A metal foil layer, and an outer resin layer, and a buffer layer having less reactivity than the metal foil layer is formed on the surface where the inner resin layer and the metal foil layer are in contact with each other. In this case, by further forming a buffer layer having less reactivity than the metal foil layer, the oxidation reaction of the metal foil layer is prevented even when damage occurs such as micro cracks in the internal resin layer, However, the metal foil is vulnerable to deformation such as wrinkling at the time of bending, thereby deteriorating the characteristics of the flexible battery.

In the prior art, when a bending operation of a general battery assembly is performed, compressive stress is applied to the inside of the bend, and tensile stress is applied to the opposite side of the bend, so that the external covering material surrounding the electrode assembly of the battery is expanded or narrowed. do. Therefore, a new flexible battery assembly suitable for flexible characteristics is required.

(Patent Document 1) KR10-2013-0063709 A

It is an object of the present invention to solve the above-described problems of the prior art, and it is an object of the present invention to provide a method of manufacturing an electrode assembly in which a predetermined pattern is formed on a casing material surrounding the electrode assembly, and a predetermined buffer space is provided between the casing material and the electrode assembly The present invention provides a flexible battery capable of preventing cracks from occurring in the electrode assembly and maintaining a capacity retention rate at a predetermined level or higher.

Further, the present invention is also applicable to a case where a tab for connecting an electrode lead and an electrode lead are joined together, and a reinforcing tab having a metal plate shape of a predetermined thickness is disposed between the electrode lead connecting tab and the electrode lead, The electrode lead is bent in the opposite direction by 180 ° in a state where the end portion of the electrode lead is welded on the tab for connecting the electrode lead and is directed toward the outside of the electrode assembly to minimize the local mechanical load due to the bending operation of the flexible battery, And to provide a stable flexible battery by maintaining chemical characteristics.

According to an aspect of the present invention, there is provided a flexible battery comprising: at least one unit cell having a pair of electrode plates having polarities different from each other with a separator interposed therebetween; and at least one unit cell protruding from the electrode plates, An electrode assembly including an electrode tab in a state of being exposed; And a cover member having a processed structure in which the upper and lower crimping portions are repeatedly pressed to surround the outer surface of the electrode assembly, wherein the plurality of upper crimping portions and the lower crimping portion are formed in a direction parallel to the width of the electrode assembly and the covering member And a buffer space is formed between the electrode assembly and the casing member.

The electrode assembly is in the form of a flat plate having no curvature, and the buffer space is a space between a plurality of depressing portions constituting the casing member and the electrode assembly.

One of the electrode plates is composed of one of silicon, a silicon derivative such as SiOx, a silicon-graphite composite, a tin, a silicon-tin composite, carbon and lithium, The buffer space compensates for thickness expansion and contraction.

The exterior material constituting the buffer space is a film having a thickness of 0.05 to 0.2 mm, and the height of the upper and lower depressions is 0.5 to 1.0 mm. If the height of the upper and lower tapered portions is less than 0.5 mm, the effect of buffering is difficult to see. If the height of the upper and lower tapered portions exceeds 1.0 mm, the volume of the battery excessively increases and the energy density is lowered. Needs to be.

And the width between the adjacent highest points or the width between the lowest points of the upper and lower crimping portions is 0.5 to 5 mm. If the width between the adjacent highest points or the width between the lowest points is larger than 5 mm, the bending radius at the time of bending the battery can not be made sufficiently small, so that the thickness of the casing and the allowable bending radius of the flexible battery are taken into consideration, You need to design.

The buffer may be filled with a polymer.

The polymer filled in the buffer space is an elastic polymer which has a certain elasticity and can be deformed freely by an external force. The elastic polymer may be a polyurethane, a silicone resin, a styrene butadiene rubber, a polybutadiene rubber, a nitrile rubber, Fluororubber, chloroprene rubber, and ethylene-propylene rubber, or two or more of them are mixed or laminated.

The polymer to be filled in the buffer space is a gel-like compound having a predetermined viscosity and capable of deforming freely by an external force. The gel-state compound includes polyurethane, silicone, styrene-butadiene rubber, polybutadiene rubber, Wherein the total weight ratio of the gel to the total weight ratio of the gel to the total weight ratio of the gel to the total weight ratio of the gel to the total weight of the gel, At least 5% of the polymer is comprised of the polymer.

The flexible battery includes: a reinforcing tab welded and fixed on an electrode tab constituting the electrode assembly; And a pair of electrode leads electrically connected to the electrode tab or welded in a bent state on the electrode tab by welding on the reinforcing tab, Wherein the tab for electrode parallel connection has a function of connecting electrode plates having the same polarity among a plurality of stacked electrode plates, wherein one of the pair of electrode leads is connected to the electrode lead connecting portion And the other of the pair of electrode leads is connected to the electrode lead connecting tab in the electrode lead connecting tab, and the other electrode lead is connected to the electrode lead connecting tab by being welded to the reinforcing tab of the pad structure between the tab and the electrode lead, And is bent in the opposite direction by 180 ° in a state of being welded to the electrode lead connecting tab so as to face toward the outer side of the electrode assembly.

The tab-to-tab connecting portions, in which the electrode plates having the same polarity are electrically connected in parallel through the electrode-parallel connection tabs, are taped on the separating membrane surrounding the outer surface of the outermost electrode plate forming the uppermost or lowermost end of the electrode assembly.

The tab-and-lid coupling portion between the electrode lead connecting tab and the electrode lead, which is reinforced by the reinforcing tab, is inserted into the electrode assembly. The tab-lid coupling portion including the bending coupling structure of the electrode lead, As shown in FIG.

Wherein the electrode plate constituting the electrode assembly includes a first electrode plate (E1) including both the electrode lead connecting tab and the electrode parallel connecting tab, and a second electrode plate (E1) including only the electrode parallel connecting tab E2), and an electrode mixture is coated on the second electrode plate (E2) so as to cover the electrode lead connecting tabs of the first electrode plate (E1).

According to the present invention, a predetermined pattern is formed on a casing member formed so as to surround the electrode assembly, and a predetermined buffer space is provided between the casing and the electrode assembly to prevent cracking of the electrode assembly even when bending occurs And the capacity retention rate can be maintained at a certain level or more.

1 shows an exemplary structure of an electrode assembly constituting a flexible battery according to the present invention.
Figure 2 shows an exploded view of the electrode assembly of Figure 1;
FIG. 3 illustrates a process of completing an overlay reinforcement structure using a reinforcing tab between an electrode lead connecting tab and an electrode lead according to the present invention.
4 shows a specific dimension of the reinforcing tab padded on the tab for electrode lead connection.
FIG. 5 shows a specific dimension of the lead-tab connection portion with the electrode lead that is coupled onto the tab for electrode lead connection.
FIG. 6 shows various forms of the reinforcing tab that pads between the electrode lead connecting tab and the electrode lead on the flexible battery.
FIG. 7 illustrates a process of bonding the electrode lead connecting tabs using the bending structure of the electrode leads according to the present invention.
FIG. 8 shows a specific dimension of the electrode lead portion bonded onto the tab for electrode lead connection.
9 shows a specific material of the electrode lead connecting tab and the electrode lead.
10 shows a flexible battery having an electrode assembly and a covering member surrounding the electrode assembly.
11 is a view showing a state in which a pattern such as an upper pressing portion and a lower pressing portion is formed in a direction parallel to the width of the exterior material portion in the exterior material portion constituting the flexible battery.
Fig. 12 illustrates specific shapes of the upper and lower pressing portions formed on the casing member.
Fig. 13 shows deformation occurring inside / outside of the casing member when the flexible battery is bent.
FIG. 14 shows a state in which the electrode-lead connecting tab and the electrode-lead overlapping reinforcing coupling structure and the tab-lead coupling portion including the electrode lead bending structure are inserted into the electrode assembly and the electrodes are aligned.
Fig. 15 shows a comparison between a cell to which an electrode assembly in which a tab-and-lead coupling portion is inserted and an electrode to which the electrode is aligned and a battery to which the content is not applied.
Fig. 16 shows a comparison of bending evaluations before and after inserting the tab-lid coupling portion including the overlap reinforcing coupling structure and the electrode lead bending structure into the electrode assembly at the same time.
17 shows an embodiment of an electrode plate in the form of an electrode assembly for inserting a tab-and-lid coupling portion including an overlock reinforcing coupling structure and a bending structure of an electrode lead into the electrode assembly at the same time.

Hereinafter, a flexible battery according to the present invention will be described with reference to the accompanying drawings.

The following examples are intended to illustrate the present invention and should not be construed as limiting the scope of the present invention. Accordingly, equivalent inventions performing the same functions as the present invention are also within the scope of the present invention.

In addition, in adding reference numerals to the constituent elements of the respective drawings, it should be noted that the same constituent elements are denoted by the same reference numerals even though they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

An embodiment of an electrode assembly constituting a flexible battery according to the present invention will be described with reference to FIGS. 1 and 2. FIG.

The electrode assembly 100 includes a unit cell A divided into an anode plate 10 and a cathode plate 20 with a separator 30 therebetween, an electrolyte solution serving as an ion transfer medium between the anode plate and the anode plate, And electrode tabs for separating the electrodes for parallel connection and electrode lead connection depending on the application. Any one or more of the electrode plates including the negative electrode plate 10 and the positive electrode plate 20 may be disposed on both sides of the tab for electrode parallel connection and the tab for electrode lead connection. For example, an optional cathode plate 10 disposed at the lowermost end of the electrode assembly 100 is provided with a cathode-parallel connection tab 12 and a cathode lead connection tab 14, Any positive electrode plate 20 facing the opposite side of the facing membrane is provided with a bipolar connection tab 22 and a positive electrode lead connection tab 24.

Here, the electrode plates are coated on the end surface or both surfaces of the electrode plate as the electrode current collector, and the tabs for electrode parallel connection and the tabs for connecting the electrode leads protrude from the electrode plate. On the other hand, the tabs for electrode-parallel connection and the tabs for connecting the electrode leads are exposed in an uncoated state.

The plurality of electrode plates are connected to each other through the electrode tabs for electrode parallel connection. That is, the plurality of negative electrode plates 10 and the plurality of positive electrode plates 20 are electrically connected in parallel by the tab-to-tab joints connecting the electrode tabs. Meanwhile, the electrode assembly has a structure that is electrically connected to the electrode lead exposed to the outside of the casing through the electrode lead connecting tab. The separation membrane physically separates the electrode plates, but functions to pass ions contained in the electrolytic solution.

The negative electrode plate mixture disposed at the uppermost and lowermost ends of the electrode assembly may be coated only on the end surface.

The tabs 12 and 22 for connecting the electrodes parallel to each other in a protruding state on the cathode plate 10 or the positive electrode plate 20 allow the electrode plates of the same polarity to be electrically connected in parallel with each other. The tab-to-tab joints connected in parallel are positioned on the separation membrane that surrounds the outer surface of the outermost electrode plate forming the uppermost or lowermost end of the electrode assembly, and subjected to finish taping.

In the present invention, the connection between the tab-to-tab connecting portion and the electrode lead connecting tabs (14, 24) connected in parallel to each other and the tab-to-lead connecting portion where the electrode leads are connected to each other And bonding are electrically connected through any of bonding methods including spot welding, ultrasonic welding, laser welding, and bonding by a conductive adhesive.

3, after an additional reinforcing tab 50 is reinforced on the electrode lead connecting tabs 14 and 24 disposed on one side of the electrode assembly, the electrode lead 60 is coupled to the reinforcing tab 50, A description will be given of a process of forming the overlapping structure using the reinforcing tabs 50 and the electrode lead connecting tabs 14 and 24 and the electrode lead 60. FIG. The reinforced bonding manner of the electrode lead connecting tabs 14 and 24 and the electrode lead 60 corresponds to at least one of the positive electrode tab and the negative electrode tab.

FIG. 3A is a perspective view of the electrode assembly of FIG. 3A. FIG. 3A is a side view of the electrode assembly. FIG.

3B shows a state in which the reinforcing tab 50 is coupled to the electrode lead connecting tab.

3C shows a state in which the electrode lead is attached to the electrode lead connecting tab to which the reinforcing tab 50 is attached.

FIG. 3D shows a state in which the electrode leads are coupled to the electrode lead connecting tabs to which the reinforcing tabs 50 are attached.

Referring to FIG. 4, the reinforcing tab 50 padded on the tab for electrode lead connection is physically reinforced by reinforcing the strength of the connection portion of the electrode lead connecting tab and the electrode lead 60.

A metal reinforcing tab 50 of the same type or a different type, which is one to three times thicker than the electrode lead connecting tab, is welded to the upper end of the tab for electrode lead connection extending from the electrode plate of the electrode assembly. The reinforcing tabs 50 reinforced by the overhangs and the tabs for connecting the electrode leads have the same or different widths.

The reinforcing tab 50 may have a width of 3 mm to 5 mm and a length of 2 mm to 4 mm, but the present invention is not limited thereto.

Referring to FIG. 5, the electrode leads, which are joined to the electrode lead connecting tabs by bonding on the reinforcing tabs 50 reinforced by the overhang, may have a width of 2 mm to 3 mm and a length of 0.5 mm to 1 mm However, the present invention is not limited thereto. In the present invention, the current collector of the electrode plate may be any one of a group including aluminum, stainless steel, and copper, and the electrode lead may have any one material selected from the group consisting of aluminum, nickel, and nickel coated with nickel have.

Referring to FIG. 6, the tabs for electrode lead connection and the reinforcing tabs 50 reinforced by the overhang on the tab-lead connection portions of the electrode leads are formed in one of a group including a circle, an ellipse, and a polygon.

Referring to FIG. 7, a process of assembling the electrode leads 60 on the electrode lead connecting tabs 14, 24 disposed on one side of the electrode assembly will be described.

A part of the end of the electrode lead 60 is welded to the upper ends of the electrode lead connecting tabs 14 and 24 in a state where the electrode leads 60 are arranged in parallel to the upper portions of the electrode lead connecting tabs 14 and 24 In this state, the electrode lead 60 is directed from the electrode lead connecting tabs 14, 24 toward the outer side of the electrode assembly 60 by bending the electrode lead 60 by 180 degrees.

The electrode lead connecting tabs 14 and 24 and the electrode lead 60 are bonded to each other through bending by at least one of a positive electrode tab and a negative electrode tab.

Referring to FIG. 8, the width of the electrode lead 60 coupled to the tab top for electrode lead connection extending from the electrode plate of the electrode assembly may be 2 mm to 3 mm, and the length may be 1 mm to 3 mm. On the other hand, the optimal length of the coupling portion may be 1.5 mm, but this is not limitative.

9, the current collector of the electrode plate may be any one of a group including aluminum, stainless steel, and copper, and the electrode lead may be any one of a group including copper coated with aluminum, stainless steel, nickel, You can have one material.

Referring to FIG. 10, the flexible battery according to the present invention includes a covering member 200 having a processed structure, which is formed by repeating an upper pressing portion and a lower pressing portion so as to surround the outer surface of the electrode assembly 100.

Referring to FIG. 11, a plurality of upper depressions 212 and lower depressions 214 repeatedly stamped on the upper casing member 210, a plurality of The upper stamping portion 222 and the lower stamping portion 224 are repeated in pattern and shape so that the flexible battery having the electrode assembly can be compressed and tensioned in the bending, twisting or wrinkling operation.

The plurality of upper depressions 212 and 222 and the lower depressions 214 and 224 are continuously formed in a direction parallel to the width of the electrode assembly and the casing.

The plurality of upper depressions 212 and 222 and the lower depressions 214 and 224 are depressed into upper and lower dies.

The outer casing member 200 surrounding the outer periphery of the electrode assembly 100 is formed on the upper and lower casing members 210 and 210 on the electrode assembly 100 with reference to a red dotted line formed at a mid- 220 < / RTI > That is, the plurality of upper depression portions 212 and 222 and the lower depression portions 214 and 224 repeated on the casing member 200 are formed symmetrically with respect to the ceiling portion 230, 210 and the lower cladding portion 220 in a symmetrical manner. In this state, the electrode assembly 100 is accommodated in the casing member 200 after the sealing portion 230 is vertically and symmetrically bent.

The width of the sealing portion, which is a reference for separating the upper and lower casing members 210 and 220, is 3 mm to 5 mm, and the actual sealing width may be 1 mm to 2 mm. But is not limited to.

Referring to FIG. 12, the flexible battery has a configuration in which the upper casing member 210 and the lower casing member 220 are disposed on the upper and lower sides with respect to the electrode assembly 100 disposed at the center.

A buffer space 240 is formed between the electrode assembly 100 and the casing member 200. That is, it can be confirmed that the upper casing member 210 and the lower casing member 220, which are formed in a curved shape, are closely disposed on the upper and lower surfaces of the electrode assembly 100.

Specifically, the electrode assembly 100 is in the form of a flat plate having no curvature, and the cushioning space 240 means a space between the plurality of cushioning portions constituting the casing member 200.

The negative electrode plate 10, which is an electrode plate of the present invention, may be composed of silicon, a silicon derivative such as SiOx, a silicon-graphite composite, tin, a silicon-tin composite, carbon, lithium or a combination thereof. In addition, the positive electrode plate 20 may be made of a metal oxide such as lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium cobalt-manganese oxide, lithium cobalt-nickel oxide, lithium manganese-nickel oxide, lithium cobalt- Titanium oxide, lithium iron phosphate, and combinations thereof.

The buffer space 240 functions to compensate for excessive expansion and contraction of the battery caused by charging and discharging of the flexible battery including the electrode plate.

The thickness of the upper and lower casing members 210 and 220 forming the cushioning space 240 is 0.05 to 0.2 mm and the thickness of the upper casing member 210 and the lower casing member 220 The height of the upper and lower depressions formed is 0.5 to 1.0 mm and the optimum value is 0.75 mm, but this is not limitative. (H = h '), which is a plurality of upper and lower repetitions on the outer casing, can be the same.

On the other hand, the width (a) between the plurality of lower tack portion uppermost points adjacent to the exterior material portion and the width (b) between the plurality of upper tack portion and the lowest portion are the same (a = b) to form a wavy pattern. The width between the highest point and the lowest point in the upper and lower crimp portions is suitably in the range of 0.5 to 5 mm.

The buffer space 240 may be filled with a polymer.

The polymer is characterized in that it is an elastic polymer having a certain elasticity and capable of being deformed freely by an external force. The elastic polymer is selected from the group consisting of polyurethane, silicone resin, styrene butadiene rubber, polybutadiene rubber, nitrile rubber, An ethylene-propylene rubber, or two or more of them may be mixed or laminated.

The polymer is a gel-like compound having a predetermined viscosity and capable of deforming freely by an external force. The gel-state compound may be at least one selected from the group consisting of polyurethane, silicone, styrene-butadiene rubber, polybutadiene rubber, nitrile rubber, Polypropylene vinylidene fluoride rubber, polypropylene rubber, polypropylene rubber, polypropylene vinylidene rubber, polyfluorinated vinylidene-hexafluoropropylene copolymer, or a mixture of two or more of them, wherein at least 5% Or more may be composed of the polymer.

Referring to FIG. 13, when an external force acts on the casing member constituting the flexible battery and is deformed into a bent state, tension acts on the casing member on the outer side of the flexible battery, and tension acts on the casing member inside the flexible battery. It can be confirmed that compression works.

The height (h) of the repeating plurality of upper depressions increases by h = 2h or less due to the compressive stress on the inside due to bending, twisting or wrinkling operation, and decreases to 0 or more and less than h due to tensile stress on the outside.

Referring to FIG. 14, a coupling structure between the electrode lead connecting tab and the electrode lead is adopted as a plurality of structures. The second tab-and-lid coupling portion has a structure in which a portion of an end of the electrode lead is connected to an electrode lead connecting tab (not shown) through the reinforcing tab between the tab for electrode lead connection and the electrode lead, 14, and 24, and bent toward the opposite direction by 180 degrees to face the outer side of the electrode assembly. The tab-to-tab joint portion is inserted into the electrode assembly and then the tab-to-tab joint portion is aligned after inserting the tab-and-lead joint portion including the overlock reinforcement coupling structure and the bend-

Referring to FIG. 15, there is shown a comparison between a battery employing an electrode assembly in which a tab-and-lead coupling portion is inserted and electrodes aligned, and a battery not having the above-described structure.

Referring to FIG. 16, before inserting the tab-and-lid coupling portion including the overlapped reinforcing coupling structure through the reinforcing tab 50 and the bending coupling structure of the electrode leads into the electrode assembly in the left drawing, the bending evaluation Test), it can be seen that a breakage occurred on the electrode lead connecting tab and the electrode lead connecting portion.

However, after inserting the tab-and-lid coupling portion including the overlap reinforcing coupling structure through the reinforcing tab 50 and the bending coupling structure of the electrode lead into the electrode assembly in the right drawing, the bending evaluation (bending test) It can be confirmed that a break phenomenon does not occur on the electrode lead connecting tab and the electrode lead connecting portion.

17, in order to insert the tab-lid coupling portion including the overlap reinforcing coupling structure through the reinforcing tab 50 and the bending coupling structure of the electrode lead into the electrode assembly, see.

The electrode plate constituting the electrode assembly includes a first electrode plate E1 including both an electrode lead connecting tab and an electrode parallel connecting tab on both sides and a second electrode plate E2 including only an electrode parallel connecting tab on one side ).

In the first electrode plate E1, the width and the length of the portion to which the electrode mixture is applied have W and D, respectively, and the area is WD. The vertical length of the tab for connecting the electrode leads is D '.

In the second electrode plate E2, the width and the length of the portion coated with the electrode mixture are W and D + D ', respectively, and have an area of W (D + D').

The electrode assembly is coated on the second electrode plate E2 so as to cover the tabs for connecting the electrode leads of the first electrode plate E1.

Through the above structure, it is possible to inserting and aligning the bonded tab-and-lid coupling portion into the electrode assembly, and at the same time to stably drive the cells.

Hereinafter, specific experimental conditions for a flexible battery having an overlock reinforcement engagement structure through the reinforcement tab 50 and a bending engagement reinforcement structure for an electrode lead will be exemplarily described.

The flexible battery according to the present invention was subjected to a bending test using a cylindrical structure of R20 in order to test continuous bending properties. Specifically, it is confirmed that the capacity retention ratio is 90% or more through 5,000 repeated tests.

Specific operating environment is as follows.

Nominal Capacity (mAh) 50 Energy Density (Wh / L) 114 Nominal Voltage 3.8 V Charging Voltage 4.35 V Operating Temp. -10 to 35 ° C Storage Temp. -20 to 45 ° C you Width 16 ± 0.5 mm Thickness 2 ± 0.2 mm Length 52 ± 1.0 mm

The present invention is characterized in that a reinforcing tab having a metal plate shape having a predetermined thickness is disposed between the electrode lead connecting tab and the electrode lead when joining the electrode lead connecting tab and the electrode lead constituting the electrode assembly, By joining the bending structure of the lead, the local mechanical load due to the bending operation of the flexible battery is minimized, and the electrochemical characteristics are maintained, thereby realizing a stable flexible battery.

Claims (12)

At least one unit cell having a pair of electrode plates having polarities different from each other with a separator interposed therebetween, and an electrode tab protruding from the electrode plates and having an electrode mixture uncovered; And
And a covering member having a processed structure in which the upper and lower pressing portions are repeatedly pressed to surround the outside of the electrode assembly,
The plurality of upper crimp portions and the lower crimp portions are continuously formed in a direction parallel to the widths of the electrode assembly and the covering member,
And a buffer space is formed between the electrode assembly and the outer casing.
Flexible battery.
The method according to claim 1,
The electrode assembly is in the form of a flat plate having no curvature,
Wherein the buffer space is a space between a plurality of lower depressions forming the exterior material portion,
Flexible battery.
The method according to claim 1,
One of the electrode plates is composed of one of silicon, a silicon derivative such as SiOx, a silicon-graphite composite, a tin, a silicon-tin composite, carbon and lithium, Characterized in that said buffer space compensates for thickness expansion and contraction,
Flexible battery.
The method according to claim 1,
Wherein the outer covering material constituting the buffer space is a film having a thickness of 0.05 to 0.2 mm and a height of the upper and lower depressions is 0.5 to 1.0 mm.
Flexible battery.
The method according to claim 1,
Wherein the width between the highest point and the lowest point of the upper and lower crimping portions is 0.5 to 5 mm.
Flexible battery.
3. The method of claim 2,
Characterized in that the polymer is filled in the buffer space.
Flexible battery.
The method according to claim 6,
The polymer filled in the buffer space is an elastic polymer which has a certain elasticity and can be deformed freely by an external force. The elastic polymer may be a polyurethane, a silicone resin, a styrene butadiene rubber, a polybutadiene rubber, a nitrile rubber, Fluorine rubber, chloroprene rubber, and ethylene-propylene rubber, or two or more of them are mixed or laminated.
Flexible battery.
The method according to claim 6,
The polymer to be filled in the buffer space is a gel-like compound having a predetermined viscosity and capable of deforming freely by an external force. The gel-state compound includes polyurethane, silicone, styrene-butadiene rubber, polybutadiene rubber, Wherein the total weight ratio of the gel to the total weight ratio of the gel to the total weight ratio of the gel to the total weight ratio of the gel to the total weight of the gel, Wherein at least 5% of the polymer is comprised of the polymer,
Flexible battery.
The method according to claim 1,
In the flexible battery,
A reinforcing tab welded and fixed on the electrode tab constituting the electrode assembly; And
And a pair of electrode leads which are welded on the reinforcing tab to be electrically connected to the electrode tab or welded in a bent state on the electrode tab,
Wherein the electrode tab includes an electrode lead connecting tab and an electrode parallel connecting tab,
The electrode-parallel connection tab serves to connect the electrode plates having the same polarity among the plurality of electrode plates stacked,
Wherein one of the pair of electrode leads is welded to the reinforcing tab having a pad structure between the electrode lead connecting tab and the electrode lead to be connected to the electrode lead connecting tab,
And the other of the pair of electrode leads is bent in the opposite direction by 180 degrees in a state of being welded to the electrode lead connecting tab so as to face the electrode assembly in the electrode lead connecting tab, However,
Flexible battery.
The method according to claim 1,
Wherein the tab-tab connecting portion, in which the electrode plates having the same polarity are electrically connected in parallel through the electrode-parallel connection tab, is taped on the separating membrane surrounding the outer surface of the outermost electrode plate forming the uppermost or lowermost end of the electrode assembly,
Flexible battery.
The method according to claim 1,
The tab-lead coupling portion between the electrode lead connecting tab and the electrode lead, which is reinforced by the reinforcing tab, is inserted into the electrode assembly,
Wherein the tab-and-lid coupling portion including the bending coupling structure of the electrode lead is inserted into the electrode assembly,
Flexible battery.
The method according to claim 1,
Wherein the electrode plate constituting the electrode assembly includes a first electrode plate (E1) including both the electrode lead connecting tab and the electrode parallel connecting tab, and a second electrode plate (E1) including only the electrode parallel connecting tab E2)
And an electrode mixture is coated on the second electrode plate (E2) so as to cover an electrode lead connecting tab of the first electrode plate (E1)
Flexible battery.

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