KR20190024707A - Electrode assembly with improved connection between current collector and tap, adhesive tap used here, and method for manufacturing the same - Google Patents

Abstract

Provided are an electrode assembly reducing an electrode collector by improving a connection structure between a tap and a current collector, a tap modified for manufacturing the electrode assembly, and a manufacturing method of the tap. According to the present invention, the electrode assembly comprises: a positive electrode having a positive electrode coating unit on which a positive electrode active material layer is formed on both surfaces of a positive electrode current collector and having a positive electrode collector on which the positive electrode active material layer is not formed on one surface of the positive electrode current collector; a negative electrode having a negative electrode coating unit on which a negative electrode active material layer is formed on both surfaces of a negative electrode current collector and having a negative electrode collector on which the negative electrode active material layer is not formed on one surface of the negative electrode current collector; a positive electrode tap overlapped the positive electrode current collector through a first conductive adhesive layer at the positive electrode collector and electrically connected to the positive electrode collector; a negative electrode tap overlapped the negative electrode current collector through a second conductive adhesive layer at the negative electrode collector and electrically connected to the negative electrode collector; and a separator disposed between the positive electrode and the negative electrode.

Description

[0001] The present invention relates to an electrode assembly having improved tap and current connection, an adhesive tap used therein, and a method of manufacturing the same.

The present invention relates to a secondary battery and a manufacturing method thereof. More particularly, the present invention relates to an electrode assembly having improved connection structure between a tab and a current collector as a component of a secondary battery, and a manufacturing method thereof. The present invention also relates to taps used in the manufacture of such electrode assemblies, and to methods of making such taps.

2. Description of the Related Art In recent years, demand for portable electronic products such as notebook computers, video cameras, and portable telephones has rapidly increased, and electric vehicles, storage batteries for energy storage, robots, and satellites have been developed in earnest. Are being studied actively. Among the currently commercialized rechargeable batteries, lithium secondary batteries are less likely to generate a memory effect than nickel-based rechargeable batteries, so that they are free from charge and discharge, have very low self-discharge rate, and have high energy density.

The lithium secondary battery mainly uses a lithium-based oxide and a carbonaceous material as a cathode active material and an anode active material, respectively. The lithium secondary battery includes an electrode assembly in which an anode and a cathode coated with such a cathode active material and a cathode active material respectively are disposed with a separator interposed therebetween, and a casing (case) sealingly accommodates the electrode assembly together with the electrolyte solution .

FIG. 1 is a perspective view of a conventional jelly-roll type electrode assembly, and FIG. 2 is an exploded perspective view of the electrode assembly shown in FIG. 1 before being wound.

1 and 2, a conventional jelly-roll type electrode assembly 100 includes an anode 110 and a cathode 120 and a separator 130. The separator 130 includes an anode 110 and a cathode 120, Respectively. The anode 110, the separator 130, and the cathode 120 are formed in a sheet shape, stacked in order, and then wound from one side to form a jelly roll type electrode assembly 100.

The anode 110 includes a sheet-like cathode current collector 111 and a cathode coating portion 113 having a cathode active material layer formed on the cathode current collector 111. The anode coating part 113 is coated on a part of the cathode current collector 111 and the cathode uncoated part 115 where the cathode active material layer is not formed in the cathode current collector 111 is coated on the anode And is positioned on both sides of the current collector 111. The positive electrode tab 140 is welded thereto, and the positive electrode collector 111 and the positive electrode tab 140 are connected to each other.

The negative electrode 120 includes a sheet-like negative electrode collector 121 and a negative electrode coating portion 123 having a negative electrode active material layer formed on the negative electrode collector 121. The negative electrode coating portion 123 is also coated on a part of the negative electrode collector 121 as shown in FIG. 2 and the negative electrode uncoated portion 125 where the negative electrode active material layer is not formed in the negative electrode collector 121, And is positioned on both sides of the current collector 121. The negative electrode tab 160 is welded thereto to connect the negative electrode collector 121 and the negative electrode tab 160 to each other.

3 is a schematic cross-sectional view of a case where a positive electrode tab is welded to a conventional positive electrode collector and a negative electrode tab is welded to a negative electrode collector.

3, the positive electrode collector 111 and the positive electrode tab 140 are positioned between the welding devices 180 as shown in FIG. 3 (a), and the negative electrode collector 140 121 and the negative electrode tab 160 are positioned to perform ultrasonic welding or resistance welding. 2, the positive electrode uncoated portion 115 is provided on both surfaces of the positive electrode collector 111 so that the positive electrode tab 140 is attached to the negative electrode coating portion, The non-coated portion 125 is provided on both surfaces of the negative electrode current collector 121 so that the negative electrode tab 160 is attached.

The positive electrode uncoated portion 115 and the negative electrode uncoated portion 125 cause the capacity of the electrode assembly 100 to be reduced. In the high output model, the number of the positive electrode tabs 140 and the number of the negative electrode tabs 160 increases, thereby increasing the number of the positive electrode uncoated portions 115 and the negative electrode uncoated portions 125 and thus acting as a limit.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide an electrode assembly in which a connection structure between a tab and a current collector is improved,

Another object to be solved by the present invention is to provide a modified tap suitable for manufacturing such an electrode assembly.

Another object to be solved by the present invention is to provide a method of manufacturing such a tab.

It is to be understood, however, that the present invention is not limited to the above-described problems, and other technical problems not mentioned above may be clearly understood by those skilled in the art from the description of the invention described below.

According to an aspect of the present invention, there is provided an electrode assembly including a positive electrode coating portion having a positive electrode active material layer formed on both surfaces of a positive electrode collector and a positive electrode uncoated portion having no positive electrode active material layer formed on one surface of the positive electrode collector anode; A negative electrode having a negative electrode coating portion on both surfaces of the negative electrode collector on which the negative electrode active material layer is formed and a negative electrode uncoated portion on which the negative electrode active material layer is not formed on one surface of the negative electrode collector; A positive electrode tab electrically connected to the positive electrode uncoated portion by being overlapped with the positive electrode collector through a first conductive adhesive layer; A negative electrode tab electrically connected to the negative electrode uncoated portion by being overlapped with the negative electrode collector through a second conductive adhesive layer; And a separator disposed between the anode and the cathode.

Preferably, the anode, the separator, and the cathode are wound in a laminated state.

In one embodiment, the positive electrode tab and the negative electrode tab are metal strip-shaped members having a width and a length, and the positive electrode tab has a positive electrode tab overlapping portion stacked on the positive electrode current collector and a negative electrode tab overlap portion Wherein the negative electrode tab includes a negative electrode tab overlap portion laminated on the negative electrode collector and a negative electrode tab extension portion extending from the negative electrode tab overlap portion to the outside of the negative electrode collector, 1 conductive adhesive layer is formed in the same shape and size as the positive electrode tab overlap portion and the second conductive adhesive layer is formed in the same shape and size as the negative electrode tab overlap portion.

The first and second conductive adhesive layers may include a resin and a conductive filler.

The resin preferably has a ratio of butyl acrylate / 4-hydroxybutyl acrylate = 98: 2 or ethyl hexyl acrylate / acrylic acid = 98: 2 Do.

The conductive filler may be any one of aluminum particles, carbon nanotubes (CNTs), carbon black, copper particles, and silver particles.

In the first and second conductive adhesive layers, the resin may be used in an amount of 80 to 85% based on the weight of each conductive adhesive layer. The content of the conductive filler may be 10 to 75% by weight relative to the resin.

According to another aspect of the present invention, there is provided a tab, which is a metal strap member having a width and a length, the tab being overlapped with the current collector and electrically connected to the current collector, And a tab extension extending from the tab overlapping portion to the outside of the current collector, wherein the conductive adhesive layer and the release film are laminated on the tab overlap portion in the same shape and size as the tab overlap portion. Such a tab may be referred to as an adhesive tab.

According to another aspect of the present invention, there is provided a method of manufacturing a tab, which is a metal strap member having a width and a length, the tab being electrically connected to the current collector so as to overlap with the current collector, And a tab extension extending outwardly of the current collector in the tab overlap portion, wherein the conductive adhesive liquid is coated on the tap metal plate, wherein the conductive adhesive liquid is coated in the longitudinal direction, Allowing the uncoated uncoated areas to alternate along the transverse direction such that the transverse length of the coated area corresponds to the length of the tab overlap and the transverse length of the uncoated area corresponds to the length of the tab extension; Laminating a release film covering the coating region and the uncoated region on the metal tab sheet; Curing the conductive adhesive liquid in the coating area to change it to a conductive adhesive layer; Slitting the tap metal sheet into a plurality of strips along the width direction in accordance with the width of the tabs and storing each strip in a reel form; And cutting the strip so that one of the coated region and the uncoated region is included in one of the strips, thereby forming a tab and an adhesive layer on the tab overlapping portion, wherein the conductive adhesive layer and the release film are laminated on the tab overlap portion, In the presence of a catalyst.

According to the electrode assembly of the present invention, since the non-coated portion is formed only on one surface of the current collector and the tab is attached through the conductive adhesive layer, not the welding, connection between the tab and the current collector is possible without damaging the active material coating portion. Therefore, the area of the active material coating portion can be increased, and the amount of the active material can be increased, thereby increasing the capacity of the secondary battery.

The tab according to the present invention can be readily used for manufacturing such an electrode assembly. The conductive adhesive layer included in the tab according to the present invention exhibits a greater adhesive force as compared with a tap which is adhered by a conventional welding method. The tab according to the present invention allows the secondary battery to be manufactured by omitting the conventional complicated welding process by peeling off the release film and then bonding the tab to the current collector.

The tap manufacturing method proposed by the present invention is a method suitable for mass production of such a tap and a secondary battery.

As described above, according to the present invention, the connection structure between the tab and the current collector is improved, thereby making it possible to manufacture a secondary battery having a large capacity. In particular, even if the number of taps is increased in the high output model, since the increase in the area of the plain region is smaller than that in the prior art, the capacity improvement effect is superior to the conventional model in the high output model.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the invention and, together with the description of the invention given below, serve to further the understanding of the technical idea of the invention, And should not be construed as limiting.
1 is a perspective view of a conventional jelly-roll type electrode assembly.
FIG. 2 is an exploded perspective view of the electrode assembly of FIG. 1 before being wound.
3 is a schematic cross-sectional view of a case where a positive electrode tab is welded to a conventional positive electrode collector and a negative electrode tab is welded to a negative electrode collector.
4 is a perspective view of a jelly roll type electrode assembly according to the present invention.
FIG. 5 is an exploded perspective view of the electrode assembly of FIG. 4 before being wound.
6 is an enlarged plan view of a portion A of Fig.
7 is a cross-sectional view taken along line VV 'in Fig.
8 is an enlarged cross-sectional view of part C of Fig.
Fig. 9 is an enlarged plan view of part B of Fig. 5;
10 is a sectional view in the XX 'direction of FIG.
11 is an enlarged sectional view of part D of Fig.
12 is a perspective view of a tab according to the present invention.
13 is a step-by-step schematic cross-sectional view illustrating the first method of manufacturing the tab.
14 is a step-by-step schematic cross-sectional view illustrating a second method of manufacturing the tab.
Figure 15 is a step-by-step schematic cross-sectional view illustrating a third method of making the tab.
16 and 17 are views for explaining a method of manufacturing a tab according to the present invention.
18 is a schematic view of an ultrasonic welding tap sample and an adhesive tap sample used in the experiment.
19A shows resistance measurement results according to current application time in the comparative example and the example sample.
FIG. 19B shows the result of measuring the full cell resistance after activation in the secondary battery manufactured using the sample of the embodiment.
20 is a graph showing the adhesive strength of the comparative example and the example sample.
FIG. 21 is a schematic diagram of conditions for impregnating the electrolyte in the fixing force test conditions.
22 is a photograph showing an electrode assembly sample according to the present invention before and after the clamping test.
FIG. 23 is a photograph showing whether or not the tab assembly is released by loosening the electrode assembly after the fixing force test on the electrode assembly sample according to the present invention. FIG.
24 is a graph of shear force test results of the conventional and inventive samples.
25 is a graph of DC resistance according to the number of days of storage of the conventional and inventive samples.

BRIEF DESCRIPTION OF THE DRAWINGS The objects and advantages of the present invention will be understood by the following description and will be more clearly understood by means of the embodiments of the present invention. It will also be readily apparent that the objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately It should be interpreted in accordance with the meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined.

Therefore, the embodiments described in the present specification and the configurations shown in the drawings are only the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

Adhesion is accompanied by solidification and hardening at room temperature. Adhesion is a persistent stickiness at room temperature, but adherence and adhesion belong to the concept of optical adhesiveness in that the surfaces of two objects are held together.

Adhesives are generally first solidified by any means (chemical reaction, solvent volatilization diffusion, temperature change, etc.) after bonding to a liquid of low viscosity and develop adhesion forces at the interface. The adhesive changes from a liquid state to a solid state and has a strong adhesive force. After changing to a solid state, the adhesive force disappears and it can not be reattached. The pressure-sensitive adhesive is a semi-solid having a high viscosity from the beginning and does not change its state even after the formation of the joint, that is, the solidification process is not required. The characteristics of the adhesive can be seen as being permanently attached and detached. However, the pressure-sensitive adhesive is also a type of adhesive, and in general, the pressure-sensitive adhesive is also broadly referred to as an adhesive.

Hereinafter, the adhesion was used to mean adhesion.

4 is a perspective view of a jelly roll type electrode assembly according to the present invention. FIG. 5 is an exploded perspective view of the electrode assembly of FIG. 4 before being wound. 6 is an enlarged plan view of a portion A of Fig. 7 is a cross-sectional view taken along the line V-V 'of FIG. 8 is an enlarged cross-sectional view of part C of Fig. Fig. 9 is an enlarged plan view of part B of Fig. 5; 10 is a sectional view taken along the line X-X 'in FIG. 11 is an enlarged sectional view of part D of Fig.

4 and 5, an electrode assembly 200 according to the present invention includes a pair of electrodes, for example, an anode 210, a cathode 220, and a separator 230 disposed therebetween . For convenience of explanation, FIG. 5 shows a state before the electrode assembly 200 is wound. Referring to FIG. 5, the anode 210, the separator 230, and the cathode 220 are formed in a sheet shape and stacked in order. 5, an additional separator is further formed on the anode 210 or under the cathode 220 so as to insulate the anode 210 from the cathode 220 at the time of winding. The electrode assembly 200 is encapsulated together with an electrolytic solution in a casing (case), and is made of a secondary battery. Particularly a secondary battery using a casing or a cylindrical can.

The anode 210 includes a sheet-like cathode current collector 211 and a cathode coating portion 213 having a cathode active material layer formed on the cathode current collector 211. As shown in the drawing, the anode coating portion 213 is preferably formed on both surfaces of the cathode current collector 211 in view of capacity assurance. The anode coating 213 is not formed on the entire surface of the cathode current collector 211 but is coated on a part of the cathode current collector 211 and is formed in the longitudinal direction of the cathode current collector 211 Can be coated leaving a predetermined area of the rectangle in the area. The portion where the anode active material layer is not formed and the anode coating portion 213 is not formed is referred to as the anode uncoated portion 215. In the electrode assembly 200 according to the present invention, such a cathode uncoated portion 215 is formed only on one surface of the cathode current collector 211 unlike the conventional art. A positive electrode tab 240 is provided and electrically connected to the positive electrode uncoated portion 215.

However, the position and shape of the anode uncoated portion 215 are not limited to these, but may be modified. For example, the anode coating portion 213 may be coated on the remaining portion of the anode current collector 211 leaving a predetermined area of a rectangular shape at one widthwise end of the cathode current collector 211. Or the anode coating portion 213 may be coated on both sides of the cathode current collector 211 in the longitudinal direction while leaving a predetermined area of a rectangular shape at the center portion of the cathode current collector 211. Although the positive electrode uncoated portion 215 is formed to extend from one side to the other side of the positive electrode collector 211 in the present embodiment, the positive electrode uncoated portion 215 may include a positive electrode tab 240, But may be formed to the minimum in only the overlapping area.

The cathode 220 includes a sheet-like anode current collector 221 and a cathode coating portion 223 having a cathode active material layer formed on the anode current collector 221. The negative electrode coating portion 223 is preferably formed on both surfaces of the negative electrode collector 221 as shown in Fig. The anode current collector 221 has the same shape as the cathode current collector 211. The cathode coating 223 is not formed on the entire surface of the cathode current collector 221 but is coated on a part of the anode current collector 221. As shown in Figure 5, Can be coated with a predetermined area of a rectangular shape. The portion where the negative electrode coating portion 223 is not formed because the negative electrode active material layer is not formed is referred to as a negative electrode uncoated portion 225. In the electrode assembly 200 according to the present invention, the cathode uncoated portion 225 is formed only on one surface of the anode current collector 221, unlike the prior art. A negative electrode tab 260 is provided and electrically connected to the negative electrode uncoated portion 225.

5, the positive electrode uncoated portion 215 is located at one end in the longitudinal direction of the positive electrode collector 211, the negative electrode uncoated portion 225 is positioned at one end in the longitudinal direction of the negative electrode collector 221, 215) is located. However, the positions of the positive electrode uncoated portion 215 and the negative electrode uncoated portion 225 are not limited thereto and may be the same or overlapping each other.

Further, the position and shape of the cathode uncoated portion 225 are not limited to these, but may be modified. For example, the negative electrode coating portion 223 may be coated on the remaining portion of the negative electrode collector 221 leaving a predetermined area of the rectangle at one widthwise end of the negative electrode collector 221. Or the anode coating portion 223 may be coated on both sides of the cathode current collector 221 in the longitudinal direction while leaving a predetermined rectangular area in the center portion of the anode current collector 221. Although the negative electrode uncoated portion 225 is formed to extend from one side to the other side of the negative electrode current collector 221 in the present embodiment, the negative electrode uncoated portion 225 may include a negative electrode tab 260, But may be formed to the minimum in only the overlapping area.

As the material of the positive electrode collector 211, aluminum is mainly used. Alternatively, the cathode current collector 211 may be made of stainless steel, nickel, titanium, sintered carbon, or a surface of aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver or the like. Further, if the secondary battery is made of a material having high conductivity without causing chemical change, there is no restriction to use it as the positive electrode collector 211.

The anode current collector 221 corresponding to the anode current collector 211 is mainly made of copper. Alternatively, the anode current collector 221 may be formed by surface-treating a surface of stainless steel, aluminum, nickel, titanium, sintered carbon, copper or stainless steel with carbon, nickel, Alloys and the like may be used.

The cathode active material is a lithium-based active material, and typical examples thereof include LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , LiFePO _4, or Li _{1 + z} Ni _{1 -x- y} Co _x M _y O ₂ 1, 0? Y? 1, 0? X + y? 1, 0? Z? 1, and M is a metal such as Al, Sr, Mg, La, or Mn). The negative electrode active material is a carbon-based active material, and examples of the negative electrode active material include a carbon material such as crystalline carbon, amorphous carbon, carbon composite, and carbon fiber, lithium metal, lithium alloy, and the like. It should be understood that the specific examples given above are merely illustrative, since the types and chemical compositions of the cathode active material and the anode active material may vary depending on the type of the secondary battery.

The anode coating portion 213 and the cathode coating portion 223 may further include a binder and a conductive material in addition to the active material. The binder serves to attach the active material particles to each other well and to adhere the active material to the current collector well. Typical examples thereof include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, Polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylic resin, polyvinyl chloride, Styrene-butadiene rubber, epoxy resin, nylon, and the like may be used, but the present invention is not limited thereto. The conductive material is used for imparting conductivity to the electrode. Any conductive material may be used without causing any chemical change in the battery. Examples of the conductive material include natural graphite, artificial graphite, carbon black, acetylene black, , Carbon-based materials such as carbon fibers; Metal powders such as copper, nickel, aluminum, and silver, or metal-based materials such as metal fibers; Conductive polymers such as polyphenylene derivatives; Or a mixture thereof may be used.

The separation membrane 230 is not particularly limited as long as it has a porous material. The separation membrane 230 may be formed of a porous polymer membrane such as a porous polyolefin membrane, polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-trichlorethylene, polymethyl methacrylate, polyacrylonitrile, Polyvinyl pyrrolidone, polyvinyl acetate, ethylene vinyl acetate copolymer, polyethylene oxide, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolyvinyl alcohol, cyanoethylcellulose Polyvinyl pyrrolidone, polyvinyl pyrrolidone, polyvinyl pyrrolidone, polyvinyl pyrrolidone, polyvinyl pyrrolidone, polyvinyl pyrrolidone, polyvinylpyrrolidone, polyvinylpyrrolidone, polyvinylpyrrolidone, polyvinylpyrrolidone, Sulfone, polyphen Alkylene may be formed of oxide, poly phenyl sulfide, polyethylene naphthalene, a non-woven film, a porous web (web) or a mixture film having a structure like.

At the end face or both faces of the separation membrane 230, inorganic particles may be bonded. The inorganic particles are preferably inorganic particles having a high dielectric constant of 5 or more, more preferably inorganic particles having a dielectric constant of 10 or more and a low density. This is because it can easily transfer lithium ions moving in the cell. Non-limiting examples of inorganic particles having a high dielectric constant of 5 or more is _{Pb (Zr, Ti) O 3} (PZT), Pb 1 - x La x Zr 1- y Ti y O 3 (PLZT), PB (Mg 3 Nb _{2/3) O 3 -PbTiO 3 (PMN} -PT), BaTiO 3, HfO 2, SrTiO 3, TiO 2, Al 2 O 3, ZrO 2, SnO 2, CeO 2, MgO, CaO, ZnO, Y 2 O _3, or a mixture thereof.

Referring to FIG. 6, the positive electrode tab 240 is a metal strip member having a predetermined width and length. The positive electrode tab 240 overlaps and is electrically connected to the positive electrode 210, particularly, the positive electrode collector 211 of the positive electrode uncoated portion 215. Specifically, the positive electrode tab 240 includes a positive electrode tab overlap portion 241 stacked on the positive electrode collector 211 and a positive electrode tab extension portion 243 extending from the positive electrode tab overlap portion 241 to the outside of the positive electrode collector 211 242).

The positive electrode tab overlap portion 241 is fixed to a portion of the positive electrode collector 211 where the positive electrode uncoated portion 215, that is, the portion where the positive electrode coating portion 213 is not formed. The positive electrode 210 to which the positive electrode tab 240 is fixed is sequentially laminated and wound up with the separator 230 and the negative electrode 220 so that the positive electrode tab overlap portion 241 overlaps the positive electrode 210 and the separator 230.

7, the positive electrode tab 240 is not welded to the positive electrode collector 211 but is electrically connected to the positive electrode collector 211 via the first conductive adhesive layer 250. The first conductive adhesive layer 250 has adhesiveness and fixes the anode tabs 240 to the cathode current collector 211.

Specifically, the first conductive adhesive layer 250 is formed in the same shape and size as the positive electrode tab overlap portion 241. Consideration is given to the point that the resistance varies in accordance with the length of the portion of the positive electrode current collector 211 protruding from the side surface of the positive electrode tab, that is, the length of the uncovered portion of the positive electrode tab extending portion 242. The length or the area of the first conductive adhesive layer 250 satisfying the minimum required adhesive force is derived because the resistance does not vary depending on the length of the positive electrode tab overlap portion 241 (length of the bonding portion or the first conductive adhesive layer 250) There is a need. However, in the case of the high output model, the temperature may locally rise due to current concentration when the area of the positive electrode tab overlap portion 241 is narrow, so that the entire area of the positive electrode tab overlap portion 241, Ideally, Therefore, it is preferable that the first conductive adhesive layer 250 is formed in the same shape and size as the positive electrode tab overlap portion 241.

8, the first conductive adhesive layer 250 includes a resin 251 and a conductive filler 252. The resin 251 should not react with the electrolytic solution, for example, acrylate series is preferable. The resin 251 may be a mixture of butyl acrylate / 4-hydroxybutyl acrylate = 98: 2 or ethyl hexyl acrylate / acrylic acid = 98: 2 Is particularly preferable in terms of adhesive strength. The anode tab 240 may be made of the same metal material as the cathode current collector 211. For example aluminum. In such a case, the conductive filler 252 included in the first conductive adhesive layer 250 is preferably any one of aluminum particles, carbon nanotubes (CNTs), carbon black, copper particles, and silver particles. Particularly, aluminum particles are preferable. The current path based on the aluminum material can be provided between the positive electrode tab 240, the first conductive adhesive layer 250, and the positive electrode current collector 211 without increasing the contact resistance. The aluminum particles may be spherical particles. In other respects, if the resistance is more important than continuity between materials, the conductive filler 252 is preferably copper or silver particles.

The resin 251 is used in an amount of 80 to 85% by weight of the first conductive adhesive layer 250. The content of the conductive filler (252) is 10 to 75% by weight relative to the resin (251). The remaining weight of the first conductive adhesive layer 250 may be other additives for improving the processability, such as an adhesion promoter such as an ester rubber or other resin, and a plasticizer such as polyisobutylene or phthalic acid ester. When the amount of the resin 251 is less than 80%, the amount of the resin 251 is small and it may be difficult to secure a uniform bonding area. When the amount exceeds 85%, the viscosity of the conductive adhesive liquid containing the resin (251) is too high, which may result in poor processability. When the conductive filler 252 is used in an amount less than 10% by weight, resistance is likely to increase. When the conductive filler 252 is used in an amount exceeding 75% by weight, the amount of the resin 251 may be small. When the thickness of the positive electrode tab 240 is about 100 mu m, the thickness of the first conductive adhesive layer 250 is about 10 mu m. When the amount of the resin 251 and the amount of the conductive filler 252 are satisfied as described above, a sufficiently uniform connection structure can be obtained at such a level of thickness.

The negative electrode tab 260 and the positive electrode tab 240 may be the same as those described above. 9 to 11, the negative electrode tab 260 is a metal strip-shaped member having a predetermined width and a predetermined length. The negative electrode tab 260 is electrically connected to the negative electrode 220, particularly to the negative electrode collector 221 of the negative electrode uncoated portion 225. Specifically, the negative electrode tab 260 includes a negative electrode tab overlap portion 261 stacked on the negative electrode collector 221 and a negative electrode tab extension portion 263 extending from the negative electrode tab overlap portion 261 to the outside of the negative electrode collector 221 262).

The negative electrode tab overlap portion 261 is fixed to a portion of the negative electrode collector 221 where the negative electrode uncoated portion 225, that is, the negative electrode coating portion 223 is not formed. The negative electrode 220 to which the negative electrode tab 260 is fixed is sequentially laminated and wound on the separator 230 and the positive electrode 210 so that the negative electrode tab overlap portion 261 overlaps the negative electrode 220 and the separator 230.

The negative electrode tab 260 is electrically connected to the negative electrode collector 221 by being overlapped with the negative electrode collector 221 through the second conductive adhesive layer 270 and not by welding. The second conductive adhesive layer 270 has adhesiveness and fixes the negative electrode tab 260 to the negative electrode collector 221.

Specifically, the second conductive adhesive layer 270 is formed in the same shape and size as the negative electrode tab overlap portion 261. Consideration is given to the point that the resistance varies in accordance with the length of the negative electrode tab extension portion 262 (the length of the unbonded portion) protruding from the side of the negative electrode current collector 221 on the resistance side. The resistance does not change depending on the length of the negative electrode tab overlap portion 261 (the length of the joint portion or the second conductive adhesive layer 270), so that the length or area of the second conductive adhesive layer 270 satisfying the minimum required adhesive strength is derived There is a need. However, in the case of the high output model, the temperature may locally rise due to the current concentration when the area of the negative electrode tab overlap portion 261 is narrow, so that the entire area of the negative electrode tab overlap portion 261, which contacts the negative electrode collector 221, Ideally, Therefore, it is preferable that the second conductive adhesive layer 270 is formed in the same shape and size as the negative electrode tab overlap portion 261.

As shown in FIG. 11, the second conductive adhesive layer 270 includes a resin 271 and a conductive filler 272. The resin 271 may be of the same kind as the resin 251 in the first conductive adhesive layer 250. However, the negative electrode tab 260 may be made of the same metal material as the negative electrode collector 221. For example copper. In such a case, it is preferable that the conductive filler 272 included in the second conductive adhesive layer 270 is one of aluminum particles, CNT, carbon black, copper particles and silver particles. Particularly preferred are copper particles. The path of the current based on the copper material may be provided between the negative electrode tab 260, the second conductive adhesive layer 270, and the negative electrode current collector 221 without increasing the contact resistance. That is, since the copper particles are the same as the material constituting the negative electrode tab 260, a good conductive path can be formed. The copper particles may be spherical particles. On the other hand, when more resistance is more important than continuity between materials, the conductive filler 272 is preferably silver particles.

The resin 271 is used in an amount of 80 to 85% by weight of the second conductive adhesive layer 270. The content of the conductive filler 272 is 10 to 75% by weight relative to the resin 271. The remaining weight of the second conductive adhesive layer 270 may be other additives for improving the processability, such as an adhesion promoter such as an ester rubber or other resin, and a plasticizer such as polyisobutylene or phthalic acid ester.

When the resin (271) is used in an amount of less than 80%, the amount of the resin (271) is small and it may be difficult to secure a uniform bonding area. When the amount exceeds 85%, the viscosity of the conductive adhesive liquid containing the resin (271) is too high, which may result in poor processability. When the conductive filler 272 is used in an amount less than 10% by weight, resistance is likely to increase. When the conductive filler 272 is used in an amount exceeding 75% by weight, the amount of the resin 271 is small. When the thickness of the negative electrode tab 260 is about 100 mu m, the thickness of the second conductive adhesive layer 270 is about 10 mu m. When the amount of the resin 271 and the amount of the conductive filler 272 are satisfied as described above, a sufficiently uniform connection structure can be obtained at this level of thickness. When the conductive filler 272 is spherical copper particles, its diameter is 2 to 3 占 퐉. Copper particles having a diameter of less than 2 mu m are strong in aggregation and can form a coagulated aggregate, which is not preferable for forming the second conductive adhesive layer 270 at a level of 10 mu m. Copper particles greater than 3 microns in diameter are too large to constitute the path of the appropriate current between the copper particles.

The negative electrode tab 260 and the positive electrode tab 240 may have the same shape but the present invention is not limited thereto and the negative electrode tab 260 may be longer than the positive electrode tab 240, ). ≪ / RTI > The area of the negative electrode tab 260 may be larger than the area of the positive electrode tab 240. In doing so, it is advantageous to quickly release the heat from the negative electrode tab 260 where the heat is better generated than the positive electrode tab 240.

As shown in FIG. 3 and the like, a conventional non-coated uncoated portion is welded on both sides of the current collector to weld the tab to the non-coated portion. However, in the present invention, the first and second conductive adhesive layers 250, and 270, as shown in FIG. 5, even when the active material layer is completely coated on one surface of the current collector, the uncoated portion may be formed on the other surface, so that the tap can be overlapped and fixed. In this way, by using a bonding method other than welding, it is not necessary to form an uncoated portion on the opposite surface of the surface to which the tab is adhered, so that it is possible to secure a sufficient capacity.

A method of placing the first conductive adhesive layer 250 between the positive electrode current collector 211 and the positive electrode tab 240 in manufacturing the electrode assembly 200 according to the present invention, There are various ways in which the second conductive adhesive layer 270 is placed between the anode tabs 260.

The first possible method is to stack the first conductive adhesive layer 250 on the anode uncoated portion 215 of the cathode current collector 211 and then stack the anode tabs 240 thereon. Similarly, a second conductive adhesive layer 270 is laminated on the cathode uncooler 225 of the anode current collector 221, and the anode tab 260 is stacked thereon.

The first conductive adhesive layer 250 and the second conductive adhesive layer 270 may be formed by applying a conductive adhesive liquid directly to the cathode current collector 211 and the anode current collector 221 and then curing the conductive adhesive layer. The first conductive adhesive layer 250 and the second conductive adhesive layer 270 should be positioned at appropriate positions on the cathode current collector 211 and the anode current collector 221 and the first conductive adhesive layer 250 and the A process of aligning the positive electrode tab 240 and the negative electrode tab 260 on the conductive adhesive layer 270 is necessary. During the process for manufacturing the electrode assembly 200, a process of applying and curing a conductive adhesive liquid must be added.

A second possible method is to pre-fabricate the first conductive adhesive layer 250 and the second conductive adhesive layer 270 in the form of a double-sided tape and then affix one side to the cathode current collector 211 and the anode current collector 221, And the positive electrode tab 240 and the negative electrode tab 260 are attached. The first conductive adhesive layer 250 and the second conductive adhesive layer 270 should be positioned at appropriate positions on the cathode current collector 211 and the anode current collector 221 and the first conductive adhesive layer 250, A process of aligning the positive electrode tab 240 and the negative electrode tab 260 on the conductive adhesive layer 270 is necessary.

A third possible method is to pre-fabricate and use dedicated tabs as proposed in the present invention. This tab may be referred to as an adhesive tab.

12 is a perspective view of a tab according to the present invention. The tab 360 of FIG. 12 can be used for manufacturing the electrode assembly 200 as the positive electrode tab 240 or the negative electrode tab 260 described above.

Referring to FIG. 12, the tabs 360 are metal strip-shaped members having a width and a length, which are overlapped and electrically connected to the current collector. The tab 360 includes a tab overlap portion 361 stacked on the current collector and a tab extension portion 362 extending outwardly of the current collector from the tab overlap portion 361. The conductive adhesive layer 370 and the release film 380 are laminated on the tab overlap portion 361 in the same shape and size as those of the tab overlap portion 361. [

The conductive adhesive layer 370 is the same as the first and second conductive adhesive layers 250 and 270 described above.

The tabs 360 may be formed of a metal material, a conductive filler in the conductive adhesive layer 370, or the like, depending on the use as the anode tabs 240 or the anode tabs 260.

The tabs 360 may be inserted into the electrode assembly 200 as a finished part. The release film 380 of the tab 360 is peeled off so that one side of the conductive adhesive layer 370 is exposed and the exposed side is exposed to the cathode uncooled portion 215 or the anode current collector 221 of the cathode current collector 211, The electrode assembly 210 can be overlapped and electrically connected to the positive electrode current collector 211 or the negative electrode current collector 221 and the tab 360 through a simple alignment process. 200).

Hereinafter, a method of manufacturing the tab 360 will be described. The tab 360 can be manufactured by the following three methods.

13 is a step-by-step schematic cross-sectional view illustrating the first method of manufacturing the tab.

First, the conductive adhesive liquid 369 is coated on the release film 380 (step (a)), and then the conductive adhesive liquid 369 is cured (step (b)) to form the conductive adhesive layer 370. And it is made like a double-sided tape by covering another release film 382 thereon. Thereafter, when one of the release films 382 is peeled off to expose the conductive adhesive layer 370 and stick it to the tab overlap portion 361, a tab 360 capable of adhering to the current collector is provided (Step (c) ).

14 is a step-by-step schematic cross-sectional view illustrating a second method of manufacturing the tab.

After the conductive adhesive liquid 369 is applied onto the release film 380 (step (A)), the conductive adhesive liquid 369 is placed on the tab overlap section 361 (step (B)) (Fig. The conductive adhesive liquid 369 is cured to become the conductive adhesive layer 370 and is manufactured as the adhesive tab 360 according to the present invention.

Figure 15 is a step-by-step schematic cross-sectional view illustrating a third method of making the tab.

After the conductive adhesive liquid 369 is applied onto the tab overlap portion 361 (step (i)), the release film 380 is placed thereon (step (ii)). When the conductive adhesive liquid 369 is cured to form the conductive adhesive layer 370 (step (iii)), the tab 360 according to the present invention is produced.

As a result of the experiment, it was confirmed that the second and third methods have excellent adhesion between the conductive adhesive layers including copper anode tab / copper particles as a conductive filler, and have uniform adhesive properties, compared to the first method. As a result, the conductivity will also increase and it is possible to mass-produce, so the second and third methods are more preferable.

Particularly, this third method is advantageous for the mass production of the tabs 360 and the mass production of the secondary batteries. A preferred tap manufacturing method according to the present invention is as follows.

16 and 17 are views for explaining a method of manufacturing a tab according to the present invention.

16, a conductive adhesive liquid is coated on the metal plate material 359 for tapping. This corresponds to the step (i) in Fig. At this time, as shown in FIG. 16, the coated area 374 coated with the conductive adhesive liquid in the longitudinal direction and the uncoated area 376 coated with the conductive adhesive liquid alternate in the lateral direction. The width a of the coating region 374 corresponds to the length of the tab overlap portion 361 and the width b of the uncoated region 376 corresponds to the tab extension portion 362 length. The coating region 374 is formed on the entire surface of the metal plate member 359 for tapping, but in a stripe pattern. Such a method may be a slot die coating similar to that used when applying the electrode active material layer or a method of placing a barrier film such as a bar on the uncoated region 376 and sprinkling the conductive adhesive liquid thereon Can be used.

Thereafter, a release film 380 (not shown in Fig. 16) covering the coating region 374 and the uncoated region 376 is laminated on the metal plate material 359 for tapping. This corresponds to the step (ii) of Fig.

Next, the conductive adhesive liquid in the coating area 374 is cured to change the conductive adhesive layer 370. This corresponds to the step (iii) in Fig.

17, a metal plate material 359 for tapping is slit along a plurality of strips 359 'in accordance with the width W of the tabs 360, and each strip 359' is stored in a reel form do.

When the strip 359 'is cut so that one of the strips 359' includes one coating area 374 and one uncoated area 376, the tab 359 ' It is possible to obtain the individual tabs 360 in which the conductive adhesive layer 370 and the release film 380 are laminated on the overlapping portion 361. [

The reel-shaped strip 359 'is inserted in the process of manufacturing the actual electrode assembly 200 and the strip 359' is formed so as to include one coating region 374 and one uncoated region 376 in the winder After the cut-away tabs 360 are obtained, the release film 380 is removed and the conductive adhesive layer 370 is placed on the cathode uncoated portion 215 and / or the cathode uncoated portion 225, The tabs 360 can be adhered to the current collector.

Next, experimental results related to the conventional ultrasonic welding tap and the adhesive tap according to the present invention will be described.

18 is a schematic view of an ultrasonic welding tap sample and an adhesive tap sample used in the experiment.

18 (a) is a view of a tab 160 welded to the current collector piece 121 'by ultrasonic welding as in the conventional art. Reference numeral 170 denotes three ultrasonic welding sites. A sample using welding as shown in Fig. 18 (a) is referred to as Comparative Example 1. 18 (b) shows the tab 260 according to the present invention bonded to the current collector piece 221 'through a conductive adhesive layer. In Examples 1 and 2, ethylhexyl acrylate / acrylic acid = 98: 2 was used as the resin of the conductive adhesive layer. In Examples 3 to 5, butyl acrylate / 4-hydroxybutyl acrylate Rate = 98: 2 was used. Examples 1 to 4 included copper particles with a diameter of 3 mu m. Example 5 included silver particles. The resin was used in an amount of 82% based on the weight of the conductive adhesive layer. In Examples 1 and 3, the copper particles were 10% by weight of the resin, the copper particles in Example 2 and Example 4 were 75% by weight of the resin, and the silver particles in Example 5 were 75% by weight of the resin. The thickness of the conductive adhesive layer was set at 10 mu m. In order to examine the characteristics in the case where the content of the copper particles is excessive, the condition is the same as in Example 3 or Example 4, but the case where only the copper particle content is 90% by weight of the resin is referred to as Comparative Example 2. Each sample condition is listed in the table below.

In each sample, the pieces of current collectors 121 'and 221' were copper foil, and had a width of 10 mm and a length of 58 mm. In the samples of Examples 1 to 5 and Comparative Example 2 of the present invention, the length of the tab overlap portion 261 was 34 mm and the length of the tab extension portion 262 was 6 mm. That is, the length of the tab 260 was 40 mm. The width of tab 260 was 4 mm. Tab 260 was made from a 100 um thick copper sheet. This size and thickness condition was similarly applied to the tap 160 of the comparative example 1 sample, which was a conventional ultrasonic welding sample.

First, the resistance was measured by placing a terminal at a portion labeled "measurement JIG" in the samples of FIG. The resistance is measured by applying a voltage between the terminals using Hioki's BT3562 battery hysteresis hysteresis and measuring the current between the terminals to calculate V (voltage) = I (current) R (resistance) Method. The applied voltage was 6V.

19A shows resistance measurement results according to current application time in the comparative example and the example sample. Resistances were shown for the Comparative Examples 1 and 3 samples.

As shown in Fig. 19A, in the comparative example and the example sample, the single piece resistance of the tab is 6.5 to 7 m? And equal to each other. There is little resistance variation with time.

FIG. 19B shows the result of measuring the full cell resistance after activation in the secondary battery manufactured using the sample of the embodiment. The full cell resistance was measured using a HiTi BT3562 battery high tester at an applied voltage of 6V.

Comparing the full cell resistances of Example 1 and Example 2 and comparing the full cell resistances of Example 3 and Example 4, it can be seen that the full cell resistance is decreased when the content of the conductive filler is increased. Comparing the full cell resistances of Examples 2 and 4 and Example 5, it can be seen that even when the content of the conductive filler is equal to 75% by weight, the full cell resistance is smaller when silver particles are included than copper particles . When silver particles are used instead of copper particles, the resistance can be reduced while maintaining the adhesive force.

Next, the current collector pieces 121 'and 221' are fixed on the die in the samples of FIG. 18, and the tabs 160 and 260 are lifted up by 90 degrees to the current collector pieces 121 ' 221 ') were observed and an adhesion test was conducted. The adhesion test was carried out using a 90-degree peep test, which was usually used, and was performed at a tension speed of 5 mm / s using an LS-5 measuring instrument manufactured by LLOYD.

20 is a graph showing the adhesive strength of the comparative example and the example sample.

In Fig. 20, the distance along the x-axis represents the position from one end of the tab extension to the other end of the tab overlap, that is, in the direction along the length of the tab. First, in the case of Comparative Example 1, since the adhesive force is 0 at a position of about 20 mm, it can be seen that the tab 160 is completely separated. It can be seen that the adhesive force peaks are observed at three positions before the separation, and correspond to positions corresponding to the ultrasonic welding sites 170, respectively.

In contrast, the first, third, and fourth tabs 260 of the present invention can be confirmed that the tab 260 is not detached because the adhesive force is not 0 even at a position of 40 mm corresponding to the length of the tab 260 , And the strength of the adhesive force is higher than that of the conventional welding tap of Comparative Example 1. [ As described above, it can be confirmed that the adhesive tap according to the present invention is far superior to the adhesive tap in comparison with the tap such as the conventional ultrasonic welding.

Comparison of Example 1 and Example 3 shows that the adhesion can be further improved when the resin is ethylhexyl acrylate / acrylic acid = 98: 2 and butyl acrylate / 4-hydroxybutyl acrylate = 98: 2 .

On the other hand, in Comparative Example 2, the copper particles were contained excessively, and as a result, the adhesive force was smaller than that of Comparative Example 1. [ In the result of FIG. 19B, the effect of decreasing the full cell resistance can be seen as the content of the conductive filler is increased. However, it can be understood that the content of the conductive filler can not be increased in consideration of the adhesive force result of FIG. Therefore, as suggested in the present invention, the conductive filler should have a content in the range of 10 to 75% by weight to obtain desirable results in terms of resistance and adhesion.

The clamping force in the sample of the jelly roll type electrode assembly was also verified by a pulling pull test. The tensile test was carried out at a tensile speed of 5 mm / s using an Instron universal testing machine (UTM).

The electrode assembly including the tab of Comparative Example 1 and the tab as shown in FIG. 18 (b), particularly the electrode assembly (J / R) sample including the tab of Example 3, After impregnation for 1 day in an electrolytic solution of 60 ° C for one day in a drying condition and a room temperature electrolytic solution, tensile force was applied to the tapped side and pulled out.

FIG. 21 is a schematic diagram of conditions for impregnating the electrolyte in the fixing force test conditions.

The electrolytic solution 410 is filled in the test vessel 400 and the electrode assembly including the tab as shown in FIG. 18A and the electrode assembly (J / R) sample including the tab as shown in FIG. Completely. This amount of electrolyte 410 is much larger than the amount of impregnation of the electrode assembly during the actual secondary battery manufacturing process. In other words, it created a more harsh environment.

FIG. 22 (a) shows the test results before and after the fixing test for the electrode assembly sample according to the present invention in a dry condition, that is, in a state in which the electrolyte is not impregnated (dry). FIG. 22 (b) shows before and after the fixing test for the electrode assembly sample according to the present invention in a wet state for one day at room temperature electrolytic solution. As a result of the test pulling up the tab, regardless of the type of the tab, it was confirmed that the tab was not pulled apart, but the tab was broken. That is, it was found that the fixing force is at a satisfactory level with the conventional or the present invention.

FIG. 23 (a) is a photograph showing a state in which the electrode assembly is unloaded after unloading the electrode assembly after the experiment of fixing the electrode assembly according to the present invention in a dry condition, that is, in a state in which the electrolyte is not impregnated (dry). FIG. 23 (b) is a photograph showing whether the tab assembly is loosened after fixing the electrode assembly according to the present invention in a wet state for one day at room temperature electrolytic solution. FIG. In the case of using the adhesive tap according to the present invention, both the drying condition and the impregnation condition were confirmed as the absence of the tab after the tensile test.

24 is a graph of shear force test results of the conventional and inventive samples. The tensile load was found to be equivalent to that of the present invention in the dry condition (Dry), 1 day wet in a room temperature electrolytic solution, 1 day wet in a 60 ° C electrolytic solution, and 1 day wet in a high temperature.

Long-term storage, simple cell D.C resistance was also measured. D. C Resistance Measurement The applied voltage was measured at 6 V using Hioki's BT3562 battery high tester.

25 is a graph of D.C resistance according to the number of days of storage of the conventional and inventive samples. The electrode assembly samples were stored in the state as shown in Fig. 21, and the change in the D.C resistance was monitored according to the number of days of storage. As shown in Fig. 25, in the conventional and inventive samples, no change in the D.C resistance according to the number of days of storage was observed, regardless of the type of tap, and the resistance values were found to be equivalent.

Thus, the tab according to the present invention exhibits greater adhesion when compared to the tabs that are attached by conventional welding methods. Resistance, fixing force, and long-term storage performance. Accordingly, the tab according to the present invention can be used for manufacturing an electrode assembly and a secondary battery including the electrode assembly by replacing the tab of the conventional welding method. The tab according to the present invention can be manufactured as a tacky tab, peeled off the release film, and then bonded to the current collector with a simple operation to omit the conventional complicated welding process to manufacture the secondary battery. Conventionally, in order to attach the tab to the current collecting body during the manufacturing of the conventional electrode assembly, the ultrasonic welding is performed separately, so that the equipment cost and the maintenance cost associated with the welding are incurred and the efficiency is lowered. In the present invention, this problem is solved by using an adhesive tap.

The electrode assembly of the present invention, which can be manufactured by such a method, can connect the tab and the current collector without damaging the active material coating portion. The uncoated portion may be formed only on one surface of the current collector, thereby increasing the capacity of the secondary battery.

As described above, according to the present invention, the connection structure between the tab and the current collector is improved, thereby making it possible to manufacture a secondary battery having a large capacity. In particular, even if the number of taps is increased in the high output model, since the increase in the area of the plain region is smaller than that in the prior art, the capacity improvement effect is superior to the conventional model in the high output model.

While the present invention has been described in connection with certain exemplary embodiments and drawings, it is to be understood that the invention is not limited thereto and that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims. It is to be understood that various changes and modifications may be made without departing from the scope of the appended claims.

200: electrode assembly 210: positive electrode 211: positive electrode collector
213: anode coating part 215: anode uncoated part 220: cathode
221: negative electrode current collector 223: negative electrode coating portion 225: negative electrode non-
230: separator 240: positive electrode tab 241: positive electrode tab overlapping part
242: positive electrode tab extension part 250: first conductive adhesive layer 251: resin
252: conductive filler 260: negative electrode tab 261: negative electrode tab overlap portion
262: negative electrode tab extension part 270: second conductive adhesive layer 271: resin
272: conductive filler 359: metal plate material for tapping 359 ': strip
360: tab 361: tab overlap portion 362: tab extension portion
370: conductive adhesive layer 374: coating area 376: uncoated area
380: release film

Claims (14)

A positive electrode having a positive electrode coating portion on which a positive electrode active material layer is formed on both surfaces of a positive electrode collector and a positive electrode uncoated portion on which the positive electrode active material layer is not formed on one surface of the positive electrode collector;
A negative electrode having a negative electrode coating portion on both surfaces of the negative electrode collector on which the negative electrode active material layer is formed and a negative electrode uncoated portion on which the negative electrode active material layer is not formed on one surface of the negative electrode collector;
A positive electrode tab electrically connected to the positive electrode uncoated portion by being overlapped with the positive electrode collector through a first conductive adhesive layer;
A negative electrode tab electrically connected to the negative electrode uncoated portion by being overlapped with the negative electrode collector through a second conductive adhesive layer; And
And a separator disposed between the anode and the cathode. The electrode assembly according to claim 1, wherein the positive electrode, the separator, and the negative electrode are wound in a laminated state. The battery pack according to claim 1, wherein the positive electrode tab and the negative electrode tab are metal strap members each having a width and a length,
Wherein the positive electrode tab includes a positive electrode tab overlap portion laminated on the positive electrode collector and a positive electrode tab extension portion extending to the outside of the positive electrode collector in the positive electrode tab overlap portion,
Wherein the negative electrode tab includes a negative electrode tab overlap portion laminated on the negative electrode collector and a negative electrode tab extension portion extending to the outside of the negative electrode collector in the negative electrode tab overlap portion,
Wherein the first conductive adhesive layer is formed in the same shape and size as the positive electrode tab overlap portion, and the second conductive adhesive layer is formed in the same shape and size as the negative electrode tab overlap portion. The electrode assembly of claim 1, wherein the first and second conductive adhesive layers comprise a resin and a conductive filler. The method of claim 4, wherein the resin is selected from the group consisting of butyl acrylate / 4-hydroxybutyl acrylate = 98: 2, ethyl hexyl acrylate / acrylic acid, = 98: 2. The electrode assembly according to claim 5, wherein the conductive filler is any one of aluminum particles, carbon nanotubes (CNTs), carbon black, copper particles, and silver particles. A tab, which is a metal strip-shaped member which is overlapped with and electrically connected to a current collector and has a width and a length,
Wherein the tabs include a tab overlap portion that is stacked on the current collector and a tab extension portion that extends to the outside of the current collector in the tab overlap portion,
Wherein the conductive adhesive layer and the release film are laminated on the tab overlap portion with the same shape and size as those of the tab overlap portion. The tab according to claim 7, wherein the conductive adhesive layer comprises a resin and a conductive filler. The method of claim 8, wherein the resin is selected from the group consisting of butyl acrylate / 4-hydroxybutyl acrylate = 98: 2, ethyl hexyl acrylate / acrylic acid, = 98: 2. The tab according to claim 9, wherein the conductive filler is any one of aluminum particles, CNTs, carbon black, copper particles, and silver particles. A method of manufacturing a tab, which is a metal strip-shaped member which is overlapped and electrically connected to a current collector and has a width and a length,
Wherein the tabs include a tab overlap portion that is stacked on the current collector and a tab extension portion that extends to the outside of the current collector in the tab overlap portion,
Wherein a conductive adhesive liquid is coated on a metal plate material for tapping so that a coated region in which the conductive adhesive liquid is coated in the longitudinal direction and an uncoated region that is not coated alternately are positioned alternately along the transverse direction, Making the width of the uncoated region correspond to the length of the overlapping portion and the width of the uncoated region to the length of the tab extension;
Laminating a release film covering the coating region and the uncoated region on the metal tab sheet;
Curing the conductive adhesive liquid in the coating area to change it to a conductive adhesive layer;
Slitting the tap metal sheet into a plurality of strips along the width direction in accordance with the width of the tabs and storing each strip in a reel form; And
The strip is cut so that one of the coating region and the uncoated region is included in one of the strips and an individual tab having the conductive adhesive layer and the release film laminated on the tab overlap portion in the same shape and size as the tab overlap portion ≪ / RTI > 12. The method of claim 11, wherein the conductive adhesive layer comprises a resin and a conductive filler. The method of claim 12, wherein the resin is selected from the group consisting of butyl acrylate / 4-hydroxybutyl acrylate = 98: 2, ethyl hexyl acrylate / acrylic acid, = 98: 2. 14. The method of claim 13, wherein the conductive filler is one of aluminum particles, CNTs, carbon black, copper particles, and silver particles.

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