Electrode assembly and manufacturing method thereof, cylindrical battery cell including the electrode assembly, and battery pack and automobile including the cylindrical battery cell

Abstract

The electrode assembly of the present invention is a jelly-roll-like electrode assembly in which sheet-like first and second electrode current collectors and a separator interposed therebetween are wound in one direction, and at least one of the first and second electrode current collectors includes a plain area at a long side end that is exposed to the outside of the separator along the longitudinal direction of the electrode assembly, and at least one of the plain areas of the first and second electrode current collectors has a cutting line formed in the longitudinal direction of the electrode assembly, and the plain area along the cutting line is divided into a remaining area that remains in a shape that protrudes in the winding axis direction based on the cutting line and a folding target area that is to be folded in a predetermined direction, and at least a portion of the plain area included in the folding target area is folded so that it overlaps with multiple layers in the predetermined folding direction of the plain area.

Description

[Technical field]

[0001] This application claims priority to Korean Patent Application No. 10-2021-0022896 filed on February 19, 2021, Korean Patent Application No. 10-2021-0103388 filed on August 5, 2021, Korean Patent Application No. 10-2021-0137200 filed on October 15, 2021, and Korean Patent Application No. 10-2021-0183106 filed on December 20, 2021, and the contents disclosed in the specifications and drawings of such applications are incorporated into this application in their entirety.

[0002] The present invention relates to an electrode assembly and a manufacturing method thereof, a cylindrical battery cell including the electrode assembly, and a battery pack and a vehicle including the cylindrical battery cell. [Background technology]

[0003] Secondary batteries, which have high applicability to each product group and electrical properties such as high energy density, are widely used not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs) that are driven by electric driving sources.

[0004] Such secondary batteries not only have the primary advantage of dramatically reducing the use of fossil fuels, but are also environmentally friendly as they do not produce any by-products from energy use, and are attracting attention as a new energy source for improving energy efficiency.

[0005] Currently, secondary batteries such as lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel metal hydride batteries, and nickel zinc batteries are widely used. The operating voltage of such a unit secondary battery cell, i.e., a unit battery cell, is about 2.5V to 4.5V. Therefore, when a higher output voltage is required, a battery pack may be configured by connecting a plurality of battery cells in series. Also, a battery pack may be configured by connecting a plurality of battery cells in parallel according to the charge / discharge capacity required for the battery pack. Therefore, the number of battery cells included in the battery pack and the electrical connection form may be variously set according to the required output voltage and / or charge / discharge capacity.

[0006] Meanwhile, known types of unit secondary battery cells include cylindrical, prismatic and pouch-type battery cells. In the case of a cylindrical battery cell, a separator, which is an insulator, is interposed between a positive electrode and a negative electrode, and the separator is wound up to form a jelly-roll-shaped electrode assembly, which is then inserted into a battery can to form a battery. A strip-shaped electrode tab is connected to each uncoated portion of the positive electrode and the negative electrode, and the electrode tab electrically connects the electrode assembly to an electrode terminal exposed to the outside. For reference, the positive electrode terminal is a cap plate of a sealing body that seals an opening of the battery can, and the negative electrode terminal is the battery can. However, according to a conventional cylindrical battery cell having such a structure, current is concentrated in the strip-shaped electrode tab connected to the positive electrode uncoated portion and / or the negative electrode uncoated portion, which results in high resistance, high heat generation and poor current collection efficiency.

[0007] Small cylindrical battery cells with form factors such as 18650 and 21700 do not have significant resistance and heat generation issues. However, when the form factor of cylindrical battery cells is increased to apply them to electric vehicles, a large amount of heat is generated around the electrode tabs during the fast charging process, which can cause the cylindrical battery cell to catch fire.

[0008] To solve these problems, a cylindrical battery cell (so-called tab-less cylindrical battery cell) has been proposed, which is designed to have positive and negative uncoated areas at the upper and lower ends of a jelly-roll-shaped electrode assembly, respectively, and has a structure in which current collecting plates are welded to these uncoated areas to improve current collection efficiency.

[0009] 1 to 3 are diagrams showing the manufacturing process of a tabless cylindrical battery cell. Fig. 1 shows the structure of an electrode plate, Fig. 2 shows the winding process of the electrode plate, and Fig. 3 shows the process of welding a current collecting plate to the bent surface of the uncoated portion.

[0010] 1 to 3, the positive electrode plate 10 and the negative electrode plate 11 have a structure in which an active material 21 is coated on a sheet-shaped current collector 20, and include a non-coated portion 22 on one long side along the winding direction X.

[0011] The electrode assembly A is manufactured by sequentially stacking a positive electrode plate 10 and a negative electrode plate 11 together with two separators 12 as shown in Fig. 2, and then winding the stack in one direction (winding direction X). At this time, the uncoated portion of the positive electrode plate 10 and the uncoated portion of the negative electrode plate 11 are arranged in opposite directions. The positions of the positive electrode plate 10 and the negative electrode plate 11 may be changed to the opposite positions from those shown in the figure.

[0012] After the winding process, the uncoated portion 10a of the positive electrode plate 10 and the uncoated portion 11a of the negative electrode plate 11 are folded toward the core side. Then, the current collecting plates 30 and 31 are welded and joined to the uncoated portions 10a and 11a, respectively.

[0013] No separate electrode tabs are attached to the positive electrode uncoated region 10a and the negative electrode uncoated region 11a, and the current collecting plates 30 and 31 are connected to external electrode terminals, and a current path is formed with a large cross-sectional area along the winding axis direction of the electrode assembly A (see arrow), which has the advantage of reducing the resistance of the battery cell. This is because resistance is inversely proportional to the cross-sectional area of ​​the path through which the current flows.

[0014] In order to improve the welding characteristics between the uncoated portions 10a, 11a and the current collecting plates 30, 31 in a tabless cylindrical battery cell, strong pressure must be applied to the welding points of the uncoated portions 10a, 11a to bend the uncoated portions 10a, 11a as flat as possible.

[0015] When bending the uncoated portions 10a and 11a, a jig for pressing the uncoated portions 10a and 11a toward the core of the electrode assembly A is used.

[0016] FIG. 4 is a close-up photograph of the bent shape of the uncoated portion, which was taken by cutting a part of the bent portion in the longitudinal direction of the electrode assembly when the uncoated portion was bent radially toward the core using a jig.

[0017] 4, it can be seen that the bend shape of the uncoated portion is not uniform, and the uncoated portion is irregularly deformed while being bent. In particular, the degree of deformation of the uncoated portion increases toward the core side of the electrode assembly. This is because the stress applied by the jig increases in the uncoated portion located closer to the core side of the electrode assembly.

[0018] If the uncoated portion is irregularly folded, the folded surface is not flat, making it difficult to weld the current collecting plate. In addition, if the uncoated portion is irregularly deformed below the folded surface, the stress caused by the irregular deformation of the uncoated portion may affect the nearby separator, causing the separator to break or the active material layer to crack, resulting in an internal short circuit. If an internal short circuit occurs, an overcurrent flows and the temperature of the cylindrical battery cell rises rapidly, which may result in the cylindrical battery cell catching fire or exploding. Summary of the Invention [Problem to be solved by the invention]

[0019] The present invention has been made in light of the background of the prior art as described above, and has an object to provide a manufacturing method for an electrode assembly that makes the folded shape of a non-coated portion uniform when folding the non-coated portion of a tab-less cylindrical battery cell, and an electrode assembly manufactured by the method.

[0020] Another object of the present invention is to provide a cylindrical battery cell including an electrode assembly manufactured by the improved method.

[0021] It is yet another object of the present invention to provide an electrode assembly having improved energy density and reduced resistance.

[0022] It is yet another object of the present invention to provide a cylindrical battery cell including an electrode assembly of an improved structure, a battery pack including the same, and a vehicle including the battery pack.

[0023] The technical problem that the present invention is to solve is not limited to the above-mentioned problem, and other problems will be clearly understood by those skilled in the art from the following description of the invention. [Means for solving the problem]

[0024] In order to achieve the above object, an electrode assembly according to the present invention is a jelly roll-shaped electrode assembly in which sheet-shaped first and second electrode collectors and a separator interposed therebetween are wound in one direction, at least one of the first and second electrode collectors includes a non-coated portion at a long side end portion exposed to the outside of the separator along a longitudinal direction of the electrode assembly, at least one of the non-coated portions of the first and second electrode collectors has a cut line formed in the longitudinal direction of the electrode assembly, the non-coated portion where the cut line is formed is divided into a remaining region that remains in a shape protruding in a winding axis direction based on the cut line and a folding target region that is folded in a predetermined direction, and at least a portion of the non-coated portion included in the folding target region is folded so as to overlap with a plurality of layers in a predetermined folding direction of the non-coated portion.

[0025] Preferably, a current collecting plate having a shape corresponding to the shape of the folding target area may be coupled to the uncoated portion of the folding target area.

[0026] Preferably, the current collecting plate may be joined by welding to a plain portion folded region that is folded to overlap a plurality of layers in the folding target region.

[0027] Preferably, the cut line may be formed by at least one cut.

[0028] In one embodiment, the cutting line may be formed by a cutter that ultrasonically vibrates in the winding axis direction of the electrode assembly.

[0029] In another aspect, the overall height of the collecting plate and the uncoated portion after the collecting plate is bonded to the uncoated portion of the folding target area may correspond to the height of the uncoated portion remaining in a shape protruding in the winding axis direction of the remaining area.

[0030] In yet another embodiment, the total height of the current collecting plate and the underlying uncoated portion in the folding target area may be the same as the height of the protruding uncoated portion in the remaining area.

[0031] Preferably, a gap may be formed between any one of the uncoated portions in the remaining region and another uncoated portion.

[0032] Desirably, the electrolyte may be arranged to move through the gap.

[0033] In one embodiment, the predetermined blank portion may be folded along the cut line.

[0034] Preferably, the predetermined uncoated portion may be folded in a radial direction of the electrode assembly.

[0035] Preferably, the predetermined uncoated portion may be folded toward a core of the electrode assembly.

[0036] Preferably, the shape of the bending target area may extend along a radial direction when viewed from a winding axis direction of the electrode assembly.

[0037] Preferably, the bending target region may have a shape that extends radially outward from a center of the core of the electrode assembly when viewed in a winding axis direction of the electrode assembly.

[0038] Preferably, the shape of the bending target region may be a shape that extends radially outward in two or more directions from a center of the core of the electrode assembly when viewed in a winding axis direction of the electrode assembly.

[0039] Preferably, the shape of the bending target area may be a cross extending outward from a center of the core of the electrode assembly when viewed in a winding axis direction of the electrode assembly.

[0040] Preferably, the shape of the bending target area, when viewed from the winding axis direction of the electrode assembly, extends radially outward from the center of the core of the electrode assembly, and the cutting line may be bent in an arc shape toward the core of the electrode assembly.

[0041] In one aspect, at least a portion of the uncoated portion included in the folding target area may be folded toward a core direction of the electrode assembly.

[0042] Preferably, at least a portion of the uncoated portion included in the folding target area may be folded to overlap at least three layers along a radial direction of the electrode assembly.

[0043] Preferably, at least a portion of the uncoated portion included in the folding target area may be folded to overlap at least four layers along a radial direction of the electrode assembly.

[0044] Preferably, at least a portion of the uncoated portion included in the folding target area may be folded to overlap at least five layers along a radial direction of the electrode assembly.

[0045] In one embodiment, an electrode plate may be formed including the first electrode collector and an active material layer formed on at least one surface of the first electrode collector, the electrode plate may include an insulating coating layer formed at a boundary between the active material layer and an uncoated portion of the first electrode collector, the insulating coating layer may be exposed to an outside of the separator, and a lower end of a cutting line around the folding target region may be spaced apart from an end of the insulating coating layer.

[0046] In another aspect, an electrode plate may be formed including the second electrode collector and an active material layer formed on at least one surface of the second electrode collector, the electrode plate may include an insulating coating layer formed at a boundary between the active material layer and an uncoated portion of the second electrode collector, the insulating coating layer may be exposed to an outside of the separator, and a lower end of a cutting line around the folding target region may be spaced apart from an end of the insulating coating layer.

[0047] In order to achieve the above object, a method for manufacturing an electrode assembly according to the present invention includes the steps of: (a) preparing a sheet-shaped first electrode collector and a sheet-shaped second electrode collector each having an uncoated portion on one side in a longitudinal direction; (b) stacking the first electrode collector, the second electrode collector, and the separator at least once to form an electrode collector-separator laminate such that the separator is interposed between the first electrode collector and the second electrode collector, and the uncoated portion of the first electrode collector and the uncoated portion of the second electrode collector are exposed on opposite sides in a longitudinal direction of the separator; and (c) winding up the electrode collector-separator laminate in one direction to form the first electrode collector. (d) forming a jelly-roll-shaped electrode assembly such that the uncoated portion of the current collector and the uncoated portion of the second electrode current collector are exposed on opposite sides along the winding axis direction; (d) forming cut lines in the longitudinal direction of the electrode assembly such that at least one of the uncoated portions of the first electrode collector and the second electrode collector is divided into a remaining area that remains in a shape protruding in the winding axis direction and a folding target area that is folded in a predetermined direction; and (e) folding at least a portion of the uncoated portion included in the folding target area so that it overlaps in multiple layers in a predetermined folding direction of the plain portion.

[0048] Preferably, a current collecting plate having a shape corresponding to the shape of the folding target area may be coupled to the uncoated portion of the folding target area.

[0049] Preferably, the method includes the step of connecting the current collecting plate to the uncoated portion of the bending target area by welding.

[0050] Preferably, the method includes forming the cutting line by a cutter that ultrasonically vibrates in a winding axial direction of the electrode assembly.

[0051] Preferably, the method includes the step of folding the predetermined blank portion along the cut line.

[0052] According to one aspect, the cutting lines in the bending target area are multiple, and when viewed from the winding axis direction of the electrode assembly, the multiple cutting lines may extend along the radial direction of the electrode assembly in pairs of two.

[0053] According to another aspect, the cutting lines in the bending target area may be multiple, and when viewed from the winding axis direction of the electrode assembly, the multiple cutting lines may extend radially outward from the core center of the electrode assembly in pairs of two.

[0054] According to yet another aspect, the bending target area has multiple cutting lines, and when viewed from the winding axis direction of the electrode assembly, each of the multiple cutting lines may be an arc curved toward the core center of the electrode assembly.

[0055] Preferably, in step (e), at least a portion of the uncoated portion included in the bending target area may be bent toward a core of the electrode assembly.

[0056] Preferably, in step (e), at least a portion of the uncoated portion included in the folding target area may be folded so as to overlap at least three layers along a radial direction of the electrode assembly.

[0057] Preferably, in step (e), at least a portion of the uncoated portion included in the folding target area may be folded so as to overlap at least four layers along a radial direction of the electrode assembly.

[0058] Preferably, in step (e), at least a portion of the uncoated portion included in the folding target area may be folded so as to overlap at least five layers along a radial direction of the electrode assembly.

[0059] In order to achieve the above object, a cylindrical battery cell according to the present invention is a jelly-roll-shaped electrode assembly in which sheet-shaped first and second electrode collectors and a separator interposed therebetween are wound in one direction, at least one of the first and second electrode collectors includes a non-coated portion at a long side end portion exposed to an outside of the separator along a longitudinal direction of the electrode assembly, at least one of the non-coated portions of the first and second electrode collectors has a cut line formed in the longitudinal direction of the electrode assembly, and the non-coated portion with the cut line formed thereon protrudes in a winding axis direction based on the cut line. the electrode assembly being divided into a remaining area remaining in a predetermined shape and a folding target area to be folded in a predetermined direction, and at least a portion of the plain area included in the folding target area being folded so as to overlap in a plurality of layers in a predetermined folding direction of the plain area; a cylindrical battery can in which the electrode assembly is housed and which is electrically connected to the second electrode current collector; a sealing body which seals an open end of the battery can; an external terminal which is electrically connected to the first electrode current collector and has a surface exposed to the outside; and a current collecting plate which is welded to the folded surface of the plain area and which is electrically connected to either the battery can or the external terminal.

[0060] The above object is also achieved by a battery pack including the above-mentioned cylindrical battery cell, and a vehicle including the same. Effect of the Invention

[0061] According to one aspect of the present invention, a cutter that ultrasonically vibrates in the winding axis direction of the electrode assembly forms a cutting line in the plain portion corresponding to the edge of the folding target area, and the plain portion of the folding target area is folded, thereby improving the flatness of the plain portion relative to the folding surface and mitigating the phenomenon of the plain portion being irregularly folded below the folding surface.

[0062] The present invention has a variety of other effects, which will be described with reference to the embodiments, but the description of effects that can be easily inferred by a person skilled in the art will be omitted.

[0063] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention, serve to further understand the technical ideas of the present invention. Therefore, the present invention should not be interpreted as being limited only to the matters described in the drawings. [Brief description of the drawings]

[0064] [Figure 1] FIG. 1 is a plan view showing the structure of an electrode plate used in manufacturing a conventional tabless cylindrical battery cell. [Diagram 2] 1 is a diagram showing a winding process of an electrode plate of a conventional tabless cylindrical battery cell. [Diagram 3] 1A and 1B are diagrams illustrating a process of welding a current collecting plate to a bent surface of a non-coating portion in a conventional tabless cylindrical battery cell. [Figure 4] 1 is a photograph showing an enlarged view of the bent shape of the uncoated portion after a jig is used to bend the uncoated portion toward the core in the radial direction and cutting a portion of the bent portion in the longitudinal direction of the electrode assembly. [Diagram 5] FIG. 2 is a plan view showing a structure of an electrode plate according to an embodiment of the present invention. [Figure 6] 1 is a cross-sectional view of a jelly-roll-shaped electrode assembly in which an electrode plate according to an embodiment of the present invention is applied to a first electrode collector and a second electrode collector, taken along a Y axis. [Figure 7]FIG. 2 is a plan view of a cutter used to form cut lines in a solid portion according to an embodiment of the present invention. [Figure 8] 8 is a cross-sectional view taken along the line AA' in FIG. 7. [Figure 9] 1 is a diagram illustrating a configuration of an ultrasonic cutter according to an embodiment of the present invention; [Figure 10] 1 is a plan view of a cutter according to various variations of the present invention; [Figure 11] 1 is a plan view of a cutter according to various variations of the present invention; [Figure 12] 1 is a plan view of a cutter according to various variations of the present invention; [Figure 13] 5 is a schematic perspective view illustrating a state after cutting lines are formed in an uncoated portion of an electrode assembly using a cutter according to an embodiment of the present invention; FIG. [Figure 14] FIG. 14 is a plan view of FIG. [Figure 15] 14 is a schematic perspective view of a plain portion folded along the cutting line shown in FIG. 13 and a current collecting plate coupled to the upper side of the folded plain portion. FIG. [Figure 16] FIG. 16 is a plan view of FIG. [Figure 17] 13 is a plan view illustrating a state after cutting lines are formed in an uncoated portion of an electrode assembly using a cutter according to another embodiment of the present invention. FIG. [Figure 18] 2 is a cross-sectional view of a cylindrical battery cell according to an embodiment of the present invention taken along a Y-axis direction. FIG. [Figure 19] FIG. 4 is a cross-sectional view of a cylindrical battery cell according to another embodiment of the present invention taken along the Y-axis direction. [Figure 20] 1 is a diagram illustrating a schematic configuration of a battery pack according to an embodiment of the present invention; [Figure 21] FIG. 21 is a diagram for explaining a vehicle including the battery pack of FIG. 20. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0065] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings. Prior to this, the terms and words used in the present specification and claims should not be interpreted as being limited to their ordinary and dictionary meanings, but should be interpreted as having meanings and concepts corresponding to the technical ideas of the present invention, in accordance with the principle that the inventor himself can appropriately define the concepts of terms in order to best describe the invention.

[0066] Therefore, it should be understood that the embodiment described in this specification and the configurations shown in the drawings are merely the most preferred embodiment of the present invention and do not represent the entire technical idea of ​​the present invention, and that there may be various equivalents and modifications that can be substituted for them at the time of this application.

[0067] In addition, in order to facilitate understanding of the invention, the accompanying drawings may not be drawn to scale, and the dimensions of some components may be exaggerated. In addition, the same reference numerals may be used to refer to the same components in different embodiments.

[0068] First, an electrode assembly according to an embodiment of the present invention will be described. The electrode assembly is a jelly roll-shaped electrode assembly having a structure in which sheet-shaped first and second electrode collectors and a separator interposed therebetween are wound in one direction and a central hole is formed in a core.

[0069] Preferably, at least one of the first electrode collector and the second electrode collector includes an uncoated portion on a long side edge in the winding direction where the active material is not coated, and at least a portion of the uncoated portion is used as an electrode tab by itself.

[0070] FIG. 5 is a plan view showing the structure of an electrode plate 40 according to an embodiment of the present invention.

[0071] Referring to FIG. 5, the electrode plate 40 includes an electrode current collector 41 made of a metal foil, and an active material layer 42. The metal foil is made of a conductive metal. The metal foil may be aluminum or copper, and is appropriately selected according to the polarity of the electrode plate 40. The active material layer 42 is formed on at least one surface of the electrode current collector 41, and includes a non-coated portion 43 at the long side end in the winding direction X. The non-coated portion 43 is an area where the active material is not coated. An insulating coating layer 44 may be formed at the boundary between the active material layer 42 and the non-coated portion 43. The insulating coating layer 44 is formed so that at least a portion of the insulating coating layer 44 overlaps the boundary between the active material layer 42 and the non-coated portion 43. The insulating coating layer 44 includes a polymer resin and may include an inorganic filler such as Al2O3. The polymer resin may have a porous structure. The polymer resin is not particularly limited as long as it is an insulating material. The polymeric resin may be polyolefin, polyimide, polyethylene terephthalate, polybutylene fluoride, etc., but the present invention is not limited thereto.

[0072] Preferably, a portion of the uncoated portion 43 adjacent to the core side may be cut off through a notching process. In this case, even if the uncoated portion 43 is bent toward the core side, the core of the electrode assembly is not blocked by the bent portion of the uncoated portion 43. For reference, the core has a cavity that is created when the bobbin used in winding the electrode assembly is removed. The cavity may be used as a passage for injecting electrolyte or a passage for inserting a welding jig. In the drawings, the dashed line indicates the lowest position at which the uncoated portion 43 can be bent. The bending of the uncoated portion 43 is performed at or above the dashed line.

[0073] The cut portion B of the uncoated portion 43 forms a plurality of winding turns in the radial direction when the electrode plate 40 is wound. The plurality of winding turns have a predetermined width in the radial direction. Preferably, the width d of the cut portion B and the folding length h of the uncoated portion 43 can be adjusted so that the predetermined width is equal to or greater than the folding length h of the uncoated portion 43. This prevents the core of the electrode assembly from being blocked even when the uncoated portion 43 is folded.

[0074] When forming the cut portion B of the uncoated portion 43, it is preferable to provide a gap G between the cutting line and the insulating coating layer 44 to prevent damage to the active material layer 42 and / or the insulating coating layer 44. The gap G is preferably 0.2 to 4 mm. If the gap G is adjusted to be within the above numerical range, it is possible to prevent the active material layer 42 and / or the insulating coating layer 44 from being damaged due to cutting tolerances when the uncoated portion 43 is cut.

[0075] In a specific example, when the electrode plate 40 is used to manufacture an electrode assembly for a cylindrical battery cell of form factor 46800, the width d of the cut portion B of the uncoated portion may be set to 180 to 350 mm depending on the diameter of the electrode assembly core.

[0076] On the other hand, when the core of the electrode assembly is not used in the electrolyte injection process, welding process, or the like, the cut portion B of the non-coating portion 43 does not need to be formed.

[0077] The electrode plate 40 of the above-described embodiment may be applied to a first electrode collector and / or a second electrode collector included in a jelly-roll-shaped electrode assembly. In addition, when the electrode plate structure of the embodiment is applied to either the first electrode collector or the second electrode collector, a conventional electrode plate structure (FIG. 1) may be applied to the other. In addition, the electrode plate structures applied to the first electrode collector and the second electrode collector may not be the same, but may be different.

[0078] In the present invention, the positive electrode active material coated on the first electrode collector and the negative electrode active material coated on the second electrode collector may be any active material known in the art without any limitations.

[0079] As an example, the positive electrode active material can be represented by the general chemical formula A[A x M y ]O 2+z(A contains at least one element of Li, Na, and K; M contains at least one element selected from Ni, Co, Mn, Ca, Mg, Al, Ti, Si, Fe, Mo, V, Zr, Zn, Cu, Al, Mo, Sc, Zr, Ru, and Cr; x ≧ 0, 1 ≦ x + y ≦ 2, -0.1 ≦ z ≦ 2; the stoichiometric coefficients x, y, and z are selected such that the compound maintains electrical neutrality) may contain an alkali metal compound represented thereby.

[0080] As another example, the positive electrode active material is an alkali metal compound xLiM disclosed in U.S. Patent No. 6,677,082, U.S. Patent No. 6,680,143, etc. 1 O2-(1-x)Li2M 2 O3 (M 1 contains at least one element having an average oxidation state of 3; M 2 contains at least one element having an average oxidation state of 4; 0 ≦ x ≦ 1).

[0081] As yet another example, the positive electrode active material has the general chemical formula Li a M 1 x Fe 1-x M 2 y P 1-y M 3 z O 4-z (M 1 contains at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, and Al; M 2 contains at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, Al, As, Sb, Si, Ge, V, and S; M 3 contains a halogen group element selectively containing F; 0 < a ≦ 2, 0 ≦ x ≦ 1, 0 ≦ y < 1, 0 ≦ z < 1; the stoichiometric coefficients a, x, y, and z are selected such that the compound maintains electrical neutrality), or may be a lithium metal phosphate represented by Li3M2(PO4)3 [M contains at least one element selected from Ti, Si, Mn, Fe, Co, V, Cr, Mo, Ni, Al, Mg, and Al].

[0082] Preferably, the positive electrode active material may include primary particles and / or secondary particles formed by agglomeration of the primary particles.

[0083] For example, the negative electrode active material may be a carbon material, lithium metal or a lithium metal compound, silicon or a silicon compound, tin or a tin compound, etc. Metal oxides such as TiO2 and SnO2 having a potential of less than 2 V may also be used as the negative electrode active material. The carbon material may be either low crystalline carbon or high crystalline carbon.

[0084] The separator may be a porous polymer film, for example, a porous polymer film made of a polyolefin polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, an ethylene / methacrylate copolymer, etc., used alone or in combination. As another example, the separator may be a conventional porous nonwoven fabric, for example, a nonwoven fabric made of a high melting point glass fiber, a polyethylene terephthalate fiber, etc.

[0085] At least one surface of the separation membrane may include a coating layer of inorganic particles. Alternatively, the separation membrane itself may be made of a coating layer of inorganic particles. The particles constituting the coating layer may have a structure in which they are bound with a binder such that there is an interstitial volume between adjacent particles.

[0086] The inorganic particles may be made of an inorganic material having a dielectric constant of 5 or more. As a non-limiting example, the inorganic particles may be made of Pb(Zr,Ti)O3 (PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT), PB(Mg3Nb 2 / 3)O3-PbTiO3 (PMN-PT), BaTiO3, hafnia (HfO2), SrTiO3, TiO2, Al2O3, ZrO2, SnO2, CeO2, MgO, CaO, ZnO, and Y2O3.

[0087] The electrode assembly according to the embodiment is a jelly-roll-shaped electrode assembly 50 in which the electrode plate 40 according to the embodiment is applied to a first electrode current collector and a second electrode current collector.

[0088] FIG. 6 is a cross-sectional view of a jelly-roll-shaped electrode assembly 50 in which the electrode plate 40 according to an embodiment of the present invention is applied to a positive electrode plate and a negative electrode plate, taken along the Y axis.

[0089] The positive electrode plate 45 may be a first electrode collector having an active material layer formed on at least one surface thereof, and the negative electrode plate 47 may be a second electrode collector having an active material layer formed on at least one surface thereof.

[0090] 6, the electrode assembly 50 may be manufactured by the winding method described with reference to FIG. 2. The uncoated portion 43a protruding upward of the electrode assembly 50 extends from the positive electrode plate 45. The uncoated portion 43b protruding downward of the electrode assembly 50 extends from the negative electrode plate 47. The separator 46 is interposed between the positive electrode plate 45 and the negative electrode plate 47. The length of the active material coated region of the positive electrode plate 45 in the Y-axis direction may be shorter than the length of the active material coated region of the negative electrode plate 47 in the Y-axis direction. Therefore, the active material coated region of the negative electrode plate 47 may extend longer in the Y-axis direction than the active material coated region of the positive electrode plate 45.

[0091] Preferably, the insulating coating layer 44 formed at the boundary between the active material region and the uncoated portion 43a, 43b of the positive electrode plate 45 and the negative electrode plate 47 may extend to the end of the separator 46 or may be exposed from the end. When the insulating coating layer 44 is exposed to the outside of the separator 46, it can play a role in supporting the folding points when the uncoated portions 43a, 43b are folded. If the folding points are supported, the stress applied to the active material layer 42 and the separator 46 when the uncoated portions 43a, 43b are folded is relieved. In addition, the insulating coating layer 44 can prevent the positive electrode plate 45 and the negative electrode plate 47 from contacting each other and causing a short circuit. In this case, the folding target region D may have a shape protruding outward from the insulating coating layer 44.

[0092] The positive electrode plate 45 of the electrode plates 40 includes a first electrode collector and an active material coating layer formed on at least one surface thereof, and the first electrode collector (uncoated portion 43a) may have a thickness of 180 to 220 μm. The negative electrode plate 47 includes a second electrode collector and an active material coating layer formed on at least one surface thereof, and the second electrode collector (uncoated portion 43b) may have a thickness of 140 to 180 μm. The separator is interposed between the positive electrode plate 45 and the negative electrode plate 47, and may have a thickness of 8 to 18 μm.

[0093] In the wound structure of the positive electrode plate 45, the interval between the uncoated portions 43a located on adjacent winding turns may be 350 to 380 μm. In the wound structure of the negative electrode plate 47, the interval between the uncoated portions 43b located on adjacent winding turns may be 350 to 380 μm.

[0094] In the electrode assembly 50, the number of winding turns of the positive electrode plate 45 varies depending on the form factor of the cylindrical battery cell, but may be 48 to 56. The number of winding turns of the negative electrode plate 47 also varies depending on the form factor of the cylindrical battery cell, but may be 48 to 56.

[0095] The blank portions 43a, 43b are longer than the blank portions applied to the design of the small cylindrical battery cell. Desirably, the blank portions 43a, 43b may be 6 mm or more, optionally 7 mm or more, optionally 8 mm or more, optionally 9 mm or more, optionally 10 mm or more, optionally 11 mm or more, or optionally 12 mm or more.

[0096] 7 and 8 are diagrams showing the structure of a cutter 60 used to form cutting lines 100 in uncoated areas 43a, 43b according to an embodiment of the present invention, where FIG. 7 is a plan view of the cutter 60 and FIG. 8 is a cross-sectional view taken along A-A' of FIG. 7.

[0097] 7 and 8, a cutter 60 according to an embodiment includes a cutter body 61 and a plurality of cutter knives 62, and a groove 63 may be provided in the center of the cutter body 61. Preferably, the cutter body 61 may be coupled to a horn 64 of an ultrasonic cutter. The ultrasonic cutter will be described later.

[0098] Preferably, the cutter body 61 is made of a metal material such as an aluminum alloy, a titanium alloy, a carbon steel, etc. The cutter knife 62 is made of a metal material such as a carbon steel, an alloy steel, a high-speed steel, a cast alloy, a cermet, a cubic boron nitride, a ceramic, a diamond, etc.

[0099] The lower ends of the cutter knives 62 may be embedded in the cutter body 61. Alternatively, the lower ends of the cutter knives 62 may be welded to the cutter body 61 after being inserted into grooves formed in the cutter body 61.

[0100] Each of the cutter knives 62 extends outward from the center of the cutter body 61 and has a strip shape standing vertically with respect to the surface of the cutter body 61 .

[0101] Preferably, the cutter knives 62 may be arranged in pairs and extend in parallel from the center of the cutter body 61 to the outside. The area between the two cutter knives 62 extending in parallel corresponds to the folding target area D of the plain portions 43a and 43b.

[0102] The cutter knives 62 are arranged in pairs of two and extend radially from the center of the cutter body 61, and the angles between the pairs of cutter knives 62 may be substantially the same.

[0103] For example, the number of cutter knives 62 may be eight in total. In this case, the pairs of cutter knives 62 extending radially form an angle of 90° with each other. As will be described later, the manner in which the pairs of cutter knives 62 extend radially may be modified in various ways.

[0104] In an embodiment of the present invention, the cutter 60 may be included in an ultrasonic cutting machine.

[0105] FIG. 9 is a diagram showing a schematic configuration of an ultrasonic cutter 70 according to an embodiment of the present invention.

[0106] Referring to FIG. 9 , an ultrasonic cutting machine 70 according to an embodiment may include a converter 71 , a booster 72 , a horn 73 and a cutter 74 .

[0107] The converter 71 generates ultrasonic vibrations. The converter 71 may include a magnetic vibrator for generating ultrasonic waves. The booster 72 amplifies the ultrasonic waves generated by the converter 71 and transmits them to the horn 73. The horn 73 transmits the ultrasonic vibrations amplified by the booster 72 to the cutter 74. The cutter 74 may be the above-mentioned cutter 60. In this case, the lower part of the cutter body 61 of the cutter 60 may be connected to the horn 73 by a method such as bolt / nut fastening, riveting, welding, etc. When the horn 73 connected to the cutter 74 is moved in the cutting direction while being brought into contact with the workpiece, the workpiece is cut by the ultrasonically vibrating cutter 74.

[0108] Although not shown, the ultrasonic cutter machine 70 may further include a mechanical and / or electronic mechanism for linear and / or rotational movement of the horn 73, a station at which the workpiece is fixed, and / or a servo motor and / or a linear motor and / or an air cylinder that supports the linear and / or rotational movement of the horn 73; and / or a drive source thereof; and / or electronic control equipment thereof, etc.

[0109] The above-described configuration of the ultrasonic cutting machine 70 is well known in the art, and it will be apparent to one skilled in the art that various components necessary for linear and / or rotational movement of the horn 73 may be further coupled to the ultrasonic cutting machine 70.

[0110] However, those skilled in the art will appreciate that the structure of the cutter 60 can be modified in a variety of ways.

[0111] 10 to 12 are plan views of cutters 60a, 60b, and 60c according to various modified examples of the present invention.

[0112] 10 to 12, cutter 60a has a structure in which a pair of cutter knives 62 extend radially at an angle of 120° to each other, while cutter 60b has a structure in which a pair of cutter knives 62 extend radially at an angle of 180° to each other.

[0113] As another modification, the cutter 60c may include an arc-shaped cutter knife 62 recessed toward the center of the cutter body 61. The arc shape of the cutter knife 62 may be point-symmetric, left-right symmetric, or up-down symmetric with respect to the center of the cutter body 61. The cutter knife 62 has an arc shape, but has a structure that extends radially with respect to the center of the cutter body 61. The number of cutter knives 62 having an arc shape is not limited to four, and can be adjusted to two or three. In this case, it is preferable that the cutter knives 62 are arranged at equal intervals in the circumferential direction of the cutter body 61.

[0114] The cross-sectional structure of the cutter knife 62 included in the cutters 60a, 60b, and 60c of various modified examples is substantially the same as that shown in Fig. 8, and can be used as a cutter 74 of an ultrasonic cutter machine 70. In this case, the cutter body 61 can be coupled to a horn 73 of the ultrasonic cutter machine 70.

[0115] Meanwhile, according to an embodiment of the present invention, the uncoated portions 43 a, 43 b of the electrode assembly 50 may be divided into a remaining region R that remains in a shape protruding in the winding axis direction based on the cutting line 100 after the cutting line 100 is formed in the longitudinal direction of the electrode assembly by the cutters 60, 60 a, 60 b, 60 c, and a folding target region D that is folded in a preset direction.

[0116] Preferably, the bending direction of the predetermined uncoated portions 43a, 43b may be a radial direction of the electrode assembly 50. Also, preferably, the bending direction of the predetermined uncoated portions 43a, 43b may be a core direction of the electrode assembly 50.

[0117] FIG. 13 is a schematic perspective view showing the state after cutting lines 100 are formed in the uncoated portions 43a, 43b of the electrode assembly 50 using a cutter 60 according to an embodiment of the present invention, and FIG. 14 is a plan view of FIG.

[0118] 13 and 14, at least one of the uncoated portion 43a of the first electrode collector and the uncoated portion 43b of the second electrode collector has a cutting line 100 formed in the longitudinal direction of the electrode assembly, and the uncoated portions 43a, 43b are divided into a remaining region R that remains in a shape that protrudes in the winding axis direction based on the cutting line 100, and a folding target region D that is folded in a preset direction. That is, the uncoated portions 43a, 43b of the remaining region R are maintained in an unfolded state, and the uncoated portions 43a, 43b of the folding target region D are folded in a preset direction.

[0119] Preferably, the non-coated portions 43a and 43b are cut in the winding axis direction (Y-axis) of the electrode assembly 50 to form a cutting line 100.

[0120] Desirably, the cut line 100 may be formed by a cutter 60 that ultrasonically vibrates in the direction of the winding axis of the electrode assembly 50 .

[0121] First, while ultrasonically vibrating the cutter 60, the cutter knife 62 is opposed to the upper surface of the electrode assembly 50, and the cutter 60 is moved along the winding axis direction (Y-axis, toward the ground) to cut the upper parts of the uncoated portions 43a, 43b to a predetermined depth, thereby forming a cutting line 100 on the edge of the folding target area D. Then, the predetermined uncoated portions 43a, 43b can be folded along the cutting line 100.

[0122] The folding target region D corresponds to a region that is folded in multiple layers for welding to the current collecting plate 80. The cutting line 100 corresponds to a region where the upper portions of the uncoated portions 43a, 43b are cut in the form of a cut line. The cutting depth may be preferably 2 to 10 mm, and the lowest point where the vertical cutting using the cutter 60 ends is preferably at a position higher than the end of the insulating coating layer 44 exposed to the outside of the separator 46 (the point indicated by the arrow in FIG. 6).

[0123] The cut line 100 may be formed by at least one cut. For example, referring to Fig. 13, the cut line 100 may be formed by one cut using the cross-shaped cutter of Fig. 7. Alternatively, although not shown, the cut line 100 may be formed by cutting once in the horizontal direction and once in the vertical direction using a pair of cutters formed in perpendicular lines. Alternatively, although not shown, the cut line 100 may be formed by eight cuts using one cutter, and other methods are also possible.

[0124] FIG. 15 is a schematic perspective view of the uncoated portions 43a, 43b folded along the cutting line 100 shown in FIG. 13 and a current collecting plate is bonded to the upper side of the folded uncoated portions 43a, 43b, and FIG. 16 is a plan view of FIG. 15.

[0125] When the uncoated portions 43a, 43b of the folding target area D shown in Fig. 13 are folded, grooves are formed along the folding direction, and a current collecting plate 80 having a shape corresponding to the shape of the grooves of the folding target area D can be coupled to the uncoated portions 43a, 43b of the folding target area D as shown in Fig. 15 and Fig. 16. In this case, the current collecting plate 80 can be coupled to the uncoated portions 43a, 43b of the folding target area D by welding. However, the coupling method of the current collecting plate 80 is not limited to welding.

[0126] If cutting lines 100 are formed in uncoated portions 43a, 43b in this manner, flatness is improved when uncoated portions 43a, 43b are folded along folding target area D, and therefore the folded shape of uncoated portions 43a, 43b can be made uniform. Furthermore, if the folded shape of uncoated portions 43a, 43b is made uniform, this has the effect of improving weldability.

[0127] 15, after the current collecting plate 80 is coupled to the uncoated portions 43a, 43b of the folding target area D, the overall height h1 of the current collecting plate 80 and the uncoated portions 43a, 43b may correspond to the height h2 of the uncoated portions 43a, 43b that remain in a shape protruding in the winding axis direction of the remaining area R. For example, the overall height h1 of the current collecting plate 80 and the uncoated portions 43a, 43b of the folding target area D may be formed to be similar to or the same as the height h2 of the protruding uncoated portions 43a, 43b of the remaining area R.

[0128] A gap g may be formed between any one of the uncoated portions 43a, 43b of the remaining region R and the other uncoated portion. The electrolyte may be configured to move through the gap. The uncoated portions 43a, 43b of the folding target region D are folded in a preset direction, and there is almost no gap between any one of the uncoated portions of the folding target region D and the other uncoated portion, so that the electrolyte does not move easily. However, since the uncoated portions 43a, 43b of the remaining region R are not folded but are oriented vertically, a gap is formed between any one of the uncoated portions 43a, 43b of the remaining region R and the other uncoated portion, and the electrolyte flows through the gap, which has the effect of improving the wettability of the electrolyte.

[0129] FIG. 17 is a view showing a state after cutting lines 100 are formed on the uncoated portions 43a and 43b of the electrode assembly 50 using a cutter 60c according to another embodiment of the present invention.

[0130] 17, first, while ultrasonically vibrating the cutter 60c, the cutter knife 62 is opposed to the upper surface of the electrode assembly 50, and the cutter 60c is moved along the winding axis direction (Y-axis, toward the ground) to cut the upper parts of the non-coated portions 43a, 43b to a predetermined depth, thereby forming a cutting line 100 on the edge of the folding target region D. The cutting line 100 has an arc shape that curves toward the core center of the electrode assembly 50. Therefore, the folding target region D is cross-shaped and has an arc-shaped edge.

[0131] The folding target region D corresponds to a region that is folded in multiple layers for welding to the current collecting plate 80. The cutting line 100 corresponds to a region formed, for example, as a notch, on the upper portion of the uncoated portions 43a, 43b. The cutting depth may be preferably 2 to 10 mm, and the lowest point where the vertical cutting using the cutter 60c ends is preferably at a position higher than the end of the insulating coating layer 44 exposed to the outside of the separator 46 (the point indicated by the arrow in FIG. 6).

[0132] Preferably, as shown in FIG. 5, the uncoated portion 43 near the core of the electrode assembly 50 has a lower height than the uncoated portion 43 in other portions, so that the folding target region D may not be formed. The folding target region D may have various shapes. As an example, the folding target region D may extend along a radial direction when viewed from the winding axis direction of the electrode assembly 50. As another example, the folding target region D may extend radially outward from the core center of the electrode assembly 50 when viewed from the winding axis direction of the electrode assembly 50. As yet another example, the folding target region D may extend radially outward in two or more directions from the core center of the electrode assembly 50 when viewed from the winding axis direction of the electrode assembly 50. As yet another example, the folding target region D may have a cross shape extending outward from the core center of the electrode assembly 50 when viewed from the winding axis direction of the electrode assembly 50. As yet another example, the shape of the bending target region D, when viewed from the winding axis direction of the electrode assembly 50, may extend radially outward from the core center of the electrode assembly 50, and the cutting line 100 may bend in an arc toward the core of the electrode assembly 50.

[0133] Referring further to FIG. 13, according to another aspect of the present invention, a folding target area D formed by cutting the uncoated portions 43a, 43b of the electrode assembly 50 along the cutting line 100 can be folded along the folding direction of a predetermined uncoated portion 43a, 43b.

[0134] Preferably, the folding direction of the predetermined uncoated portions 43a, 43b is the radial direction of the electrode assembly 50. More preferably, the folding target area D may be folded along the radial direction of the electrode assembly 50. Even more preferably, the folding target area D may be folded from the outside of the electrode assembly 50 toward the core side.

[0135] Preferably, the uncoated portions 43a and 43b included in the folding target area D may be folded along the radial direction of the electrode assembly 50, preferably from the outside toward the core side.

[0136] Desirably, the length of the folded plain portion can be adjusted within a range of 2 to 10 mm so that the folded plain portion can be overlapped along the winding axis (Y-axis) direction of the electrode assembly 50 in at least three, at least four, or at least five layers along the folding direction.

[0137] The folding target area D has a structure that extends radially along the folding direction. In addition, the uncoated portion of the folding target area D has a narrow width. Therefore, when the uncoated portion of the folding target area D is folded along the radial direction of the electrode assembly A, the folding is performed uniformly. In addition, since the width of the uncoated portion to be folded is narrow, the uncoated portions are overlapped in multiple layers, improving the flatness of the folding surface. In addition, by welding the current collecting plate 80 to the folding surface with improved flatness, the welding output can be increased, the welding strength can be sufficiently increased, and the resistance characteristics of the welding interface can be improved.

[0138] The electrode assembly 50 according to an embodiment of the present invention can be applied to a cylindrical battery cell in the form of a jelly roll.

[0139] Desirably, the cylindrical battery cell may be, for example, a cylindrical battery cell having a form factor ratio (defined as the diameter divided by the height of the cylindrical battery cell, i.e., the ratio of the diameter (Φ) to the height (H)) of greater than about 0.4.

[0140] Here, the form factor refers to a value indicating the diameter and height of a cylindrical battery cell. The cylindrical battery cell according to an embodiment of the present invention may be, for example, a 46110 cell, a 48750 cell, a 48110 cell, a 48800 cell, or a 46800 cell. In the form factor value, the first two digits indicate the diameter of the cell, the next two digits indicate the height of the cell, and the last digit 0 indicates that the cross section of the cell is circular. If the height of the cell exceeds 100 mm, three digits are needed to indicate the height, so the last digit 0 is omitted.

[0141] When an electrode assembly having a tabless structure is applied to a cylindrical battery cell having a form factor ratio exceeding 0.4, the stress applied in the radial direction when the uncoated portion is bent is large, and the uncoated portion is easily broken. Also, when welding the current collecting plate 80 to the bent surface of the uncoated portion, the number of overlapping layers of the uncoated portion must be increased sufficiently to ensure sufficient welding strength and reduce resistance. These requirements can be achieved by the electrode plate and electrode assembly according to the embodiment (variant) of the present invention.

[0142] A cylindrical battery cell according to one embodiment of the present invention may be a generally cylindrical cell having a diameter of about 46 mm, a height of about 110 mm, and a form factor ratio of 0.418.

[0143] A cylindrical battery cell according to another embodiment may be a generally cylindrical cell having a diameter of about 48 mm, a height of about 75 mm, and a form factor ratio of 0.640.

[0144] A cylindrical battery cell according to yet another embodiment may be a generally cylindrical cell having a diameter of about 48 mm, a height of about 110 mm, and a form factor ratio of 0.418.

[0145] A cylindrical battery cell according to yet another embodiment may be a generally cylindrical cell having a diameter of about 48 mm, a height of about 80 mm, and a form factor ratio of 0.600.

[0146] A cylindrical battery cell according to yet another embodiment may be a generally cylindrical cell having a diameter of about 46 mm, a height of about 80 mm, and a form factor ratio of 0.575.

[0147] Conventionally, cylindrical battery cells with a form factor ratio of about 0.4 or less have been used. That is, conventionally, for example, 18650 cells, 21700 cells, etc. have been used. In the case of 18650 cells, the diameter is about 18 mm, the height is about 65 mm, and the form factor ratio is 0.277. In the case of 21700 cells, the diameter is about 21 mm, the height is about 70 mm, and the form factor ratio is 0.300.

[0148] Hereinafter, a cylindrical battery cell according to an embodiment of the present invention will be described in detail.

[0149] FIG. 18 is a cross-sectional view of a cylindrical battery cell 190 according to one embodiment of the present invention taken along the Y-axis direction.

[0150] 18, a cylindrical battery cell 190 according to an embodiment of the present invention includes an electrode assembly 110 including a first electrode collector, a separator, and a second electrode collector wound in a jelly roll shape, a battery can 142 that houses the electrode assembly 110, and a seal 143 that seals an open end of the battery can 142. The electrode assembly 110 has the structure of the above-described embodiment.

[0151] The battery can 142 is a cylindrical container with an opening formed at the top. The battery can 142 is made of a conductive metal material such as aluminum, steel, stainless steel, etc. The battery can 142 accommodates the electrode assembly 110 in the inner space through the top opening, and also accommodates an electrolyte. A Ni coating layer may be formed on the outer and / or inner surface of the battery can 142. The battery can 142 is electrically connected to the second electrode current collector.

[0152] The electrolyte is A + B - In this case, the salt may have the structure: + Li + , Na + , K + or combinations thereof. - is F - , Cl- , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , AlO4 - , AlCl4 - , PF6 - , SbF6 - , AsF6 - , BF2C2O4 - , BC4O8 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , C4F9SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - and (CF3CF2SO2)2N - The anion includes one or more anions selected from the group consisting of:

[0153] The electrolyte may be dissolved in an organic solvent for use. The organic solvent may be propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethyl methyl carbonate (EMC), γ-butyrolactone, or a mixture thereof.

[0154] The electrode assembly 110 may have a jelly roll shape. The electrode assembly 110 may be manufactured by winding an electrode plate-separator laminate formed by sequentially stacking a lower separator, a first electrode collector, an upper separator, and a second electrode collector at least once, as shown in FIG. 2, around a winding center C.

[0155] An uncoated portion 146a of a first electrode collector and an uncoated portion 146b of a second electrode collector protrude from the upper and lower sides of the electrode assembly 110, respectively.

[0156] The sealing body 143 seals the open end of the battery can 142 and may include a cap plate 143a, a first gasket 143b that provides airtightness between the cap plate 143a and the battery can 142 and has insulating properties, and a connecting plate 143c that is electrically and mechanically connected to the cap plate 143a.

[0157] The cap plate 143a is a part made of a conductive metal material and covers an upper opening of the battery can 142. The cap plate 143a is electrically connected to the uncoated portion 146a of the first electrode collector and is electrically insulated from the battery can 142 via a first gasket 143b. Therefore, the cap plate 143a can function as a first electrode terminal of the cylindrical battery cell 190.

[0158] The cap plate 143a is placed on a beading portion 147 formed on the battery can 142 and fixed by a crimping portion 148. A first gasket 143b may be interposed between the cap plate 143a and the crimping portion 148 to ensure airtightness of the battery can 142 and to provide electrical insulation between the battery can 142 and the cap plate 143a. The cap plate 143a may have a protrusion 143d protruding upward from a center portion thereof.

[0159] The battery can 142 is electrically connected to the uncoated portion 146b of the second electrode collector, and therefore has the same polarity as the second electrode collector.

[0160] The battery can 142 has a beading portion 147 and a crimping portion 148 at its upper end. The beading portion 147 is formed by pressing in the outer circumferential surface of the battery can 142. The beading portion 147 prevents the electrode assembly 110 housed inside the battery can 142 from slipping out of the upper opening of the battery can 142, and can function as a support on which the sealed body 143 is placed.

[0161] The crimping portion 148 is formed on the upper side of the beading portion 147. The crimping portion 148 is extended and bent to surround the outer circumferential surface of the cap plate 143a disposed on the beading portion 147 and a part of the upper surface of the cap plate 143a.

[0162] The cylindrical battery cell 190 may further include a first current collecting plate 144 and / or a second current collecting plate 145 and / or an insulator 146 .

[0163] The first current collecting plate 144 is coupled to the upper part of the electrode assembly 110. The first current collecting plate 144 is made of a conductive metal material such as aluminum, copper, nickel, etc., and is electrically connected to a bent surface formed by bending an uncoated portion 146a included in a bending target region D of the first electrode collector in a radial direction of the electrode assembly 110, preferably toward a core center C. A lead 149 may be connected to the first current collecting plate 144. The lead 149 may extend upward of the electrode assembly 110 and be coupled to the connection plate 143c, or may be directly coupled to a lower surface of the cap plate 143a. The lead 149 may be coupled to other components by welding.

[0164] Preferably, the first current collecting plate 144 may be integrally formed with the lead 149. In this case, the lead 149 may be a long plate extending outward from the center of the first current collecting plate 144.

[0165] The bent surface of the non-coating portion 146a and the first current collecting plate 144 may be bonded to each other by, for example, laser welding. Laser welding may be performed by partially melting the base material of the current collecting plate. Laser welding may be replaced by resistance welding, ultrasonic welding, spot welding, etc.

[0166] A second current collecting plate 145 may be coupled to the lower surface of the electrode assembly 110. One surface of the second current collecting plate 145 may be coupled by welding to a bent surface formed by bending an uncoated portion 146b of the second electrode collector included in a bending target area D protruding downward from the electrode assembly 110 in a radial direction of the electrode assembly 110, preferably toward a core center C, and the other surface may be coupled by welding to an inner bottom surface of the battery can 142. The coupling structure between the second current collecting plate 145 and the uncoated portion 146b of the second electrode collector may be substantially the same as the coupling structure between the first current collecting plate 144 and the uncoated portion 146a of the first electrode collector.

[0167] The insulator 146 can cover the first current collecting plate 144. By covering the first current collecting plate 144 with the upper surface of the first current collecting plate 144, the insulator 146 can prevent the first current collecting plate 144 and the inner circumferential surface of the battery can 142 from directly contacting each other.

[0168] The insulator 146 has a lead hole 151 through which the lead 149 extending upward from the first current collecting plate 144 is pulled out. The lead 149 is pulled out upward through the lead hole 151 and coupled to the lower surface of the connection plate 143c or the lower surface of the cap plate 143a.

[0169] The peripheral region of the insulator 146 is interposed between the first current collecting plate 144 and the beading portion 147 to fix the combination of the electrode assembly 110 and the first current collecting plate 144. As a result, the combination of the electrode assembly 110 and the first current collecting plate 144 is restricted from moving in the height direction of the battery cell 190, and the assembly stability of the battery cell 190 can be improved.

[0170] The insulator 146 may be made of an insulating polymer resin. As an example, the insulator 146 may be made of polyethylene, polypropylene, polyimide, or polybutylene terephthalate.

[0171] The battery can 142 may further include a vent portion 152 formed on its lower surface. The vent portion 152 corresponds to a region of the lower surface of the battery can 142 that is thinner than the surrounding region. The vent portion 152 is structurally weaker than the surrounding region. Therefore, if an abnormality occurs in the cylindrical battery cell 190 and the internal pressure increases above a certain level, the vent portion 152 may burst and gas generated inside the battery can 142 may be discharged to the outside. The vent portion 152 may be a notch formed on the upper and / or lower surface of the bottom of the battery can 142. When the notch grooves are formed on both the upper and lower surfaces of the bottom of the battery can 142, it is preferable that the positions of the notches correspond to each other.

[0172] The vent portion 152 may be formed continuously or discontinuously in a circular shape on the bottom surface of the battery can 142. Alternatively, the vent portion 152 may be formed in a linear pattern or in other patterns.

[0173] FIG. 19 is a cross-sectional view of a cylindrical battery cell 200 according to another embodiment of the present invention taken along the Y axis.

[0174] Referring to FIG. 19, a cylindrical battery cell 200 differs from the cylindrical battery cell 190 shown in FIG. 18 in that the structure of the electrode assembly is substantially the same, but other structures except for the electrode assembly have been changed.

[0175] Specifically, the cylindrical battery cell 200 includes a battery can 171 in which a rivet terminal 172, which is an external terminal electrically connected to a first electrode collector and has a surface exposed to the outside, is inserted. The rivet terminal 172 is provided on a closed surface (upper surface in the drawing) of the battery can 171. The rivet terminal 172 is riveted into a through hole of the battery can 171 with an insulating second gasket 173 interposed therebetween. The rivet terminal 172 is exposed to the outside in the direction opposite to the direction of gravity.

[0176] The rivet terminal 172 includes a terminal exposing portion 172a and a terminal inserting portion 172b. The terminal exposing portion 172a is exposed to the outside of the closed surface of the battery can 171. The terminal exposing portion 172a may be located approximately in the center of the closed surface of the battery can 171. The maximum diameter of the terminal exposing portion 172a may be larger than the maximum diameter of the through hole formed in the battery can 171.

[0177] The terminal insertion portion 172b may be electrically connected to the uncoated portion 146a of the first electrode collector by penetrating approximately the center of the closed surface of the battery can 171. The portion electrically connected to the terminal insertion portion 172b is the center of a bent surface formed by bending the uncoated portion 146a of the first electrode collector included in a bending target area D protruding upward from the electrode assembly 110.

[0178] Here, the lower end surface of the terminal insertion portion 172b is substantially flat and may be welded to the center of the first current collecting plate 144 connected to the uncoated portion 146a of the first electrode collector. An insulating cap 174 made of an insulating material may be interposed between the first current collecting plate 144 and the inner surface of the battery can 171. The insulating cap 174 covers the upper portion of the first current collecting plate 144 and the upper edge of the electrode assembly 110. This prevents the uncoated portion 146a of the electrode assembly 110 from coming into contact with the inner surface of the battery can 171 having the opposite polarity, causing a short circuit. Preferably, the terminal insertion portion 172b of the rivet terminal 172 may be welded to the first current collecting plate 144 by penetrating the insulating cap 174.

[0179] The terminal insertion portion 172b may be riveted onto the inner surface of the battery can 171. That is, an end edge of the terminal insertion portion 172b may be pressed by a caulking tool and have a shape that is curved toward the inner surface of the battery can 171. The maximum diameter of the end of the terminal insertion portion 172b may be larger than the maximum diameter of the through hole of the battery can 171.

[0180] The second gasket 173 is interposed between the battery can 171 and the rivet terminal 172, and prevents the battery can 171 and the rivet terminal 172, which have opposite polarities, from being electrically connected to each other. This allows the upper surface of the battery can 171, which has a substantially flat shape, to function as a second electrode terminal of the cylindrical battery cell 200.

[0181] The second gasket 173 includes a gasket exposing portion 173a and a gasket inserting portion 173b. The gasket exposing portion 173a is interposed between the terminal exposing portion 172a of the rivet terminal 172 and the battery can 171. The gasket inserting portion 173b is interposed between the terminal inserting portion 172b of the rivet terminal 172 and the battery can 171. The gasket inserting portion 173b may be deformed when the terminal inserting portion 172b is riveted, and may come into close contact with the inner surface of the battery can 171. The second gasket 173 may be made of, for example, an insulating polymer resin.

[0182] The gasket exposing portion 173a of the second gasket 173 may be extended to cover an outer circumferential surface of the terminal exposing portion 172a of the rivet terminal 172. When the second gasket 173 covers the outer circumferential surface of the rivet terminal 172, it is possible to prevent a short circuit from occurring during the process of connecting an electrical connection part such as a bus bar to the upper surface of the battery can 171 and / or the rivet terminal 172. Although not shown, the gasket exposing portion 173a may be extended to cover not only the outer circumferential surface of the terminal exposing portion 172a but also a part of the upper surface.

[0183] When the second gasket 173 is made of a polymer resin, the second gasket 173 may be joined to the battery can 171 and the rivet terminal 172 by thermal fusion. In this case, the airtightness at the joining interface between the second gasket 173 and the rivet terminal 172 and at the joining interface between the second gasket 173 and the battery can 171 may be strengthened. Meanwhile, when the gasket exposed portion 173a of the second gasket 173 has a shape that extends to the upper surface of the terminal exposed portion 172a, the rivet terminal 172 may be integrally joined to the second gasket 173 by insert injection.

[0184] A remaining area 175 on the upper surface of the battery can 171 excluding the area occupied by the rivet terminal 172 and the second gasket 173 corresponds to a second electrode terminal having a polarity opposite to that of the rivet terminal 172 .

[0185] The second current collecting plate 176 is coupled to the lower part of the electrode assembly 110. The second current collecting plate 176 is made of a conductive metal material such as aluminum, steel, copper, or nickel, and is electrically connected to the uncoated portion 146b of the second electrode collector.

[0186] Desirably, the second current collecting plate 176 is electrically connected to the battery can 171. Therefore, the second current collecting plate 176 may be fixed with at least a portion of its edge interposed between the inner surface of the battery can 171 and the first gasket 178b. As an example, at least a portion of the edge of the second current collecting plate 176 may be fixed to the beading portion 180 by laser welding or resistance welding while being supported on a lower end surface of the beading portion 180 formed at the lower end of the battery can 171. As a modified example, at least a portion of the edge of the second current collecting plate 176 may be directly welded to the inner wall surface of the battery can 171.

[0187] Preferably, the second current collecting plate 176 and the bent surface of the non-coating portion 146b may be joined by welding, for example, laser welding, resistance welding, ultrasonic welding, spot welding, or the like.

[0188] The sealing body 178 that seals the lower open end of the battery can 171 includes a cap plate 178a and a first gasket 178b. The first gasket 178b electrically isolates the cap plate 178a from the battery can 171. The crimping portion 181 fixes the periphery of the cap plate 178a and the first gasket 178b together. The cap plate 178a is provided with a vent portion 179. The configuration of the vent portion 179 is substantially the same as that of the above-described embodiment.

[0189] Preferably, the cap plate 178a is made of a conductive metal material. However, since the first gasket 178b is interposed between the cap plate 178a and the battery can 171, the cap plate 178a does not have electrical polarity. The seal 178 seals the open end of the lower part of the battery can 171 and functions to exhaust gas when the internal pressure of the battery cell 200 increases above a critical value. The cap plate 178a may include a vent portion 179 in a peripheral region of a flat portion. The configuration of the vent portion 179 is substantially the same as that of the above-described embodiment.

[0190] Preferably, the rivet terminal 172 electrically connected to the uncoated portion 146a of the first electrode collector is used as the first electrode terminal. In addition, a portion 175 of the upper surface of the battery can 171 electrically connected to the uncoated portion 146b of the second electrode collector through the second current collecting plate 176, excluding the rivet terminal 172, is used as a second electrode terminal having a polarity different from that of the first electrode terminal. In this way, when the two electrode terminals are located at the upper portion of the cylindrical battery cell 200, it is possible to arrange an electrical connection part such as a bus bar only on one side of the cylindrical battery cell 200. This can simplify the structure of the battery pack and improve the energy density. In addition, since the portion 175 used as the second electrode terminal has a substantially flat shape, a sufficient joining area can be secured when joining an electrical connection part such as a bus bar. As a result, the cylindrical battery cell 200 can reduce the resistance at the joining portion of the electrical connection part to a suitable level.

[0191] In the present invention, the uncoated portions constituting the winding turns near the core have a low height as shown in Fig. 5. Therefore, even if the uncoated portions 146a, 146b in the folding target area D are folded toward the core center C of the electrode assembly, the cavity 112 of the core of the electrode assembly 110 is not blocked and can be opened upward.

[0192] 18 and 19, if the cavity 112 is not blocked, the electrolyte injection process is easy and the efficiency of the electrolyte injection is improved. Also, by inserting a welding jig through the cavity 112, the welding process between the current collecting plate 145 and the bottom of the battery can 142 or between the current collecting plate 144 and the rivet terminal 172 can be easily performed.

[0193] A method for manufacturing an electrode assembly according to an embodiment of the present invention will be described below, with the exception that the above description will be substituted for content common to the electrode assembly according to the embodiment of the present invention or the cylindrical battery cell according to the embodiment of the present invention.

[0194] First, a sheet-like first electrode current collector and a sheet-like second electrode current collector each having a non-coated portion on one side in the longitudinal direction are prepared.

[0195] Next, the first electrode collector, the second electrode collector, and the separator are stacked at least once to interpose the separator between the first electrode collector and the second electrode collector, and an electrode collector-separator laminate is formed such that the uncoated portion of the first electrode collector and the uncoated portion of the second electrode collector are exposed on opposite sides of the separator along the longitudinal direction.

[0196] The electrode collector-separator laminate is then wound in one direction to form a jelly-roll-shaped electrode assembly such that the uncoated portion of the first electrode collector and the uncoated portion of the second electrode collector are exposed on opposite sides along the winding axis.

[0197] Thereafter, a cutting line 100 is formed in the longitudinal direction of the electrode assembly so that at least one of the uncoated portions of the first electrode collector and the uncoated portion of the second electrode collector is divided into a remaining region R that remains in a shape protruding in the winding axis direction and a folding target region D that is folded in a preset direction. Here, the cutting line 100 may be formed by a cutter that ultrasonically vibrates in the winding axis direction of the electrode assembly. Also, a predetermined uncoated portion may be folded along the cutting line 100.

[0198] Thereafter, at least a portion of the plain portion included in the folding target area D is folded so as to overlap a plurality of layers in a predetermined folding direction of the plain portion.

[0199] After the plain portion is folded, a current collecting plate having a shape corresponding to the shape of the folding target area D is bonded to the plain portion of the folding target area D. Here, the current collecting plate can be bonded by welding to the folded area of ​​the plain portion that is folded to overlap the multiple layers of the folding target area D.

[0200] Meanwhile, the specific details regarding the cutting line 100 and the shape in the bending target area D may be replaced with the details described in the electrode assembly or cylindrical battery cell according to an embodiment of the present invention.

[0201] The cylindrical battery cells according to the above-described embodiments (variations) can be used to manufacture battery packs.

[0202] FIG. 20 is a diagram illustrating a schematic configuration of a battery pack according to an embodiment of the present invention.

[0203] 20, a battery pack 800 according to an embodiment of the present invention includes an assembly of electrically connected cylindrical battery cells 810, and a pack housing 820 that accommodates the assembly. The cylindrical battery cells 810 may be any one of the battery cells according to the above-described embodiments (variations). For convenience of illustration, components such as a bus bar for electrically connecting the cylindrical battery cells 810, a cooling unit, and external terminals are not shown in the drawings.

[0204] The battery pack 800 is mounted on an automobile 900. The automobile 900 may be, for example, an electric automobile, a hybrid automobile, or a plug-in hybrid automobile. The automobile 900 includes a four-wheeled automobile or a two-wheeled automobile.

[0205] FIG. 21 is a diagram for explaining an automobile including the battery pack of FIG.

[0206] 21, an automobile 900 according to an embodiment of the present invention includes a battery pack 800 according to an embodiment of the present invention. The automobile 900 operates by receiving a supply of power from the battery pack 800 according to an embodiment of the present invention.

[0207] According to one aspect of the present invention, a folding target area of ​​the plain portion having a shape protruding in the winding axis direction of the electrode assembly is formed in a pattern extended along the folding direction, and the plain portion of the folding target area is folded, thereby improving the flatness of the plain portion with respect to the folding surface and mitigating the phenomenon of the plain portion being folded irregularly below the folding surface.

[0208] As described above, the present invention has been described using limited embodiments and drawings. However, the present invention is not limited thereto, and it goes without saying that various modifications and variations can be made by a person having ordinary knowledge in the technical field to which the present invention belongs within the technical spirit of the present invention and the equivalent scope of the claims. [Industrial Applicability]

[0209] The present invention relates to an electrode assembly and a manufacturing method thereof, a cylindrical battery cell including the electrode assembly, and a battery pack and an automobile including the cylindrical battery cell, and is particularly applicable to the secondary battery-related industry.

Claims

1. A jelly-roll-shaped electrode assembly in which a sheet-shaped first electrode collector, a sheet-shaped second electrode collector, and a separator interposed therebetween are wound in one direction, At least one of the first electrode collector and the second electrode collector includes a non-coated portion at a long side end portion thereof, the non-coated portion being exposed to an outside of the separator along a longitudinal direction of the electrode assembly, a cut line is formed in at least one of the uncoated portion of the first electrode collector and the uncoated portion of the second electrode collector in a longitudinal direction of the electrode assembly; The non-coated portion on which the cutting line is formed is divided into a remaining region that is left in a shape protruding in a winding axis direction based on the cutting line, and a folding target region that is folded in a predetermined direction, At least a portion of the plain portion included in the folding target area is folded so as to overlap a plurality of layers in a predetermined folding direction of the plain portion, an electrode plate is formed including the first electrode collector and an active material layer formed on at least one surface of the first electrode collector; the electrode plate includes an insulating coating layer formed at a boundary between the active material layer and an uncoated portion of the first electrode collector, The insulating coating layer is exposed to the outside of the separator, a lower end of the cutting line around the fold target area is spaced apart from an end of the insulating coating layer; an electrode plate is formed including the second electrode collector and an active material layer formed on at least one surface of the second electrode collector; the electrode plate includes an insulating coating layer formed at a boundary between the active material layer and an uncoated portion of the second electrode collector, The insulating coating layer is exposed to the outside of the separator, a lower end of the cutting line around the fold target area is spaced apart from an end of the insulating coating layer; an electrode assembly, wherein only a core side of the uncoated portion of the first electrode collector and a core side of the uncoated portion of the second electrode collector are provided with a cut portion in which a remaining portion of the uncoated portion is removed so that a portion of the uncoated portion remains.

2. The electrode assembly of claim 1 , wherein a current collecting plate having a shape corresponding to the shape of the bent target area is coupled to the uncoated portion of the bent target area.

3. The electrode assembly of claim 2 , wherein the current collecting plate is coupled to the uncoated portion of the folding target area by welding.

4. 3. The electrode assembly according to claim 2, wherein an overall height of the current collecting plate and the uncoated portion after the current collecting plate is bonded to the uncoated portion of the bending target area is approximately the same as a height of the uncoated portion remaining in a shape protruding in the winding axis direction of the remaining area.

5. 5. The electrode assembly according to claim 4, wherein a total height of the current collecting plate and the uncoated portion thereunder in the folding target area is the same as a height of the protruding uncoated portion in the remaining area.

6. The electrode assembly of claim 1 , wherein a gap is formed between any one of the uncoated portions in the remaining region and another uncoated portion.

7. The electrode assembly of claim 6 , wherein an electrolyte is configured to travel through the gap.

8. The electrode assembly according to claim 1 , wherein the predetermined uncoated portion is folded along the cut line.

9. The electrode assembly according to claim 1 , wherein the predetermined non-coating portion is bent in a radial direction of the electrode assembly.

10. The electrode assembly according to claim 1 , wherein the predetermined uncoated portion is bent toward a core of the electrode assembly.

11. The electrode assembly according to claim 1 , wherein the shape of the bending target area extends along a radial direction when viewed from a winding axial direction of the electrode assembly.

12. The electrode assembly according to claim 1 , wherein the bending target region has a shape extending radially outward from a core center of the electrode assembly when viewed in a winding axial direction of the electrode assembly.

13. The electrode assembly according to claim 12, wherein the shape of the bending target region extends radially outward in two or more directions from a core center of the electrode assembly when viewed from a winding axis direction of the electrode assembly.

14. The electrode assembly according to claim 1 , wherein the shape of the bending target area is a cross extending outward from a core center of the electrode assembly when viewed in a winding axial direction of the electrode assembly.

15. The shape of the bending target region extends radially outward from a core center of the electrode assembly when viewed from a winding axis direction of the electrode assembly, The electrode assembly of claim 1 , wherein the cut line curves in an arc toward a core of the electrode assembly.

16. The electrode assembly according to claim 1 , wherein at least a portion of the uncoated portion included in the folding target area is folded toward a core direction of the electrode assembly.

17. The electrode assembly according to claim 1 , wherein at least a portion of the uncoated portion included in the folding target area is folded so as to overlap at least three layers along a radial direction of the electrode assembly.

18. The electrode assembly according to claim 1 , wherein at least a portion of the uncoated portion included in the folding target area is folded to overlap at least four layers along a radial direction of the electrode assembly.

19. The electrode assembly according to claim 1 , wherein at least a portion of the uncoated portion included in the folding target area is folded to overlap at least five layers along a radial direction of the electrode assembly.

20. (a) preparing a sheet-like first electrode collector and a sheet-like second electrode collector each having a non-coated portion on one side in a longitudinal direction; (b) forming an electrode collector-separator laminate by stacking the first electrode collector, the second electrode collector, and a separator at least once, interposing a separator between the first electrode collector and the second electrode collector, and exposing an uncoated portion of the first electrode collector and an uncoated portion of the second electrode collector on opposite sides of the separator along a longitudinal direction of the separator; (c) winding the electrode collector-separator laminate in one direction to form a jelly-roll-shaped electrode assembly such that the uncoated portion of the first electrode collector and the uncoated portion of the second electrode collector are exposed on opposite sides of a winding axis; and (d) forming a cutting line in a longitudinal direction of the electrode assembly so that at least one of the uncoated portions of the first electrode collector and the uncoated portion of the second electrode collector is divided into a remaining region that remains in a shape protruding in a winding axis direction and a folding target region that is folded in a predetermined direction; (e) folding at least a portion of the plain portion included in the folding target area in a predetermined plain portion folding direction so as to overlap a plurality of layers, an electrode plate is formed including the first electrode collector and an active material layer formed on at least one surface of the first electrode collector; the electrode plate includes an insulating coating layer formed at a boundary between the active material layer and an uncoated portion of the first electrode collector, The insulating coating layer is exposed to the outside of the separator, a lower end of the cutting line around the fold target area is spaced apart from an end of the insulating coating layer; an electrode plate is formed including the second electrode collector and an active material layer formed on at least one surface of the second electrode collector; the electrode plate includes an insulating coating layer formed at a boundary between the active material layer and an uncoated portion of the second electrode collector, The insulating coating layer is exposed to the outside of the separator, a lower end of the cutting line around the fold target area is spaced apart from an end of the insulating coating layer; a cut portion is provided only on a core side of the uncoated portion of the first electrode collector and the uncoated portion of the second electrode collector by removing a remaining portion of the uncoated portion so that a portion of the uncoated portion remains.

21. The method of claim 20 , further comprising bonding a current collecting plate having a shape corresponding to the shape of the bending target area to the uncoated portion of the bending target area.

22. The method of claim 21 , further comprising the step of: bonding the current collecting plate to a plain portion folded area folded to overlap a plurality of layers at the folding target area by welding.

23. The method for manufacturing an electrode assembly according to claim 20, further comprising forming the cutting line by a cutter that ultrasonically vibrates in a winding axial direction of the electrode assembly.

24. The method of claim 20, further comprising folding the predetermined uncoated portion along the cut line.

25. The cutting lines in the folding target area are multiple, The method for manufacturing an electrode assembly according to claim 20 , wherein the cutting lines extend in a radial direction of the electrode assembly in pairs when viewed from a winding axial direction of the electrode assembly.

26. The cutting lines in the folding target area are multiple, The method for manufacturing an electrode assembly according to claim 20 , wherein, when viewed from a winding axis direction of the electrode assembly, the cutting lines extend radially outward from a core center of the electrode assembly in pairs of two.

27. The cutting lines in the folding target area are multiple, The method for manufacturing an electrode assembly according to claim 20 , wherein each of the cutting lines has an arc shape curved toward a core center of the electrode assembly when viewed from a winding axis direction of the electrode assembly.

28. In the step (e), The method of claim 20 , wherein at least a portion of the uncoated portion included in the bending target area is bent toward a core direction of the electrode assembly.

29. In the step (e), The method of claim 20, further comprising folding at least a portion of the uncoated portion included in the folding target area so as to overlap at least three layers along a radial direction of the electrode assembly.

30. In the step (e), The method of claim 20, further comprising folding at least a portion of the uncoated portion included in the folding target area so as to overlap at least four layers along a radial direction of the electrode assembly.

31. In the step (e), The method for manufacturing an electrode assembly according to claim 20 , further comprising folding at least a portion of the uncoated portion included in the folding target area so as to overlap at least five layers along a radial direction of the electrode assembly.

32. an electrode assembly in the form of a jelly roll in which sheet-like first and second electrode collectors and a separator interposed therebetween are wound in one direction, at least one of the first and second electrode collectors includes a non-coated portion at a long side end portion exposed to the outside of the separator along a longitudinal direction of the electrode assembly, at least one of the non-coated portions of the first and second electrode collectors has a cut line formed in the longitudinal direction of the electrode assembly, the non-coated portion having the cut line is divided into a remaining region that remains in a shape protruding in a winding axis direction based on the cut line and a folding target region that is folded in a predetermined direction, and at least a portion of the non-coated portion included in the folding target region is folded in a predetermined folding direction of the non-coated portion so as to overlap in a plurality of layers; a cylindrical battery can in which the electrode assembly is housed and which is electrically connected to the second electrode current collector; a seal for sealing an open end of the battery can; an external terminal electrically connected to the first electrode collector and having a surface exposed to the outside; and a current collecting plate welded to a bent surface of the non-coating portion and electrically connected to either the battery can or the external terminal; an electrode plate is formed including the first electrode collector and an active material layer formed on at least one surface of the first electrode collector; the electrode plate includes an insulating coating layer formed at a boundary between the active material layer and an uncoated portion of the first electrode collector, The insulating coating layer is exposed to the outside of the separator, a lower end of the cutting line around the fold target area is spaced apart from an end of the insulating coating layer; an electrode plate is formed including the second electrode collector and an active material layer formed on at least one surface of the second electrode collector; the electrode plate includes an insulating coating layer formed at a boundary between the active material layer and an uncoated portion of the second electrode collector, The insulating coating layer is exposed to the outside of the separator, a lower end of the cutting line around the fold target area is spaced apart from an end of the insulating coating layer; a cut portion is provided only on a core side of the uncoated portion of the first electrode collector and the uncoated portion of the second electrode collector, in which a remaining portion of the uncoated portion is removed so that a portion of the uncoated portion remains.

33. A battery pack comprising the cylindrical battery cell of claim 32.

34. 34. A motor vehicle including the battery pack of claim 33.

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