KR20220118897A - Electrode Assembly and Method for Manufacturing the same, Cylindrical battery cell including the Electrode Assembly, and Battery pack and Vehicle including the Cylindrical batter Cell - Google Patents

Abstract

Disclosed in the present invention are 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. In a jelly roll-type electrode assembly in which a first electrode current collector and a second electrode current collector each having a sheet shape and a separator interposed therebetween are wound in one direction, at least one of the first electrode current collector and the second electrode current collector includes an uncoated part exposed to the outside of the separator in a longitudinal direction of the electrode assembly at the end of a long side thereof, a cutting line is formed in the longitudinal direction of the electrode assembly on at least one of the uncoated part of the first electrode current collector and the uncoated part of the second electrode current collector, the uncoated part on which the cutting line is formed is divided into a residual area remaining in a protruding shape in a winding axis direction based on the cutting line and an area to be bent which is bent in a preset direction, and at least a part of an uncoated part included in the area to be bent is bent to overlap a plurality of layers in a bending direction of a certain uncoated part.

Description

Electrode Assembly and Method for Manufacturing the same, Cylindrical battery cell including the Electrode Assembly, and Battery pack and Vehicle including the Cylindrical batter Cell}

The present invention relates to an electrode assembly and a method for manufacturing the same, a cylindrical battery cell including the electrode assembly, and a battery pack and an automobile including the same.

Secondary batteries that are easy to apply according to product groups and have electrical characteristics such as high energy density are not only portable devices, but also electric vehicles (EVs) or hybrid vehicles (HEVs) driven by an electric drive source. It is universally applied.

These secondary batteries are attracting attention as a new energy source for improving eco-friendliness and energy efficiency because they have the primary advantage of being able to dramatically reduce the use of fossil fuels as well as the advantage that no by-products are generated from the use of energy.

The types of secondary batteries currently widely used include a lithium ion battery, a lithium polymer battery, a nickel cadmium battery, a nickel hydrogen battery, a nickel zinc battery, and the like. The unit secondary battery cell, that is, the operating voltage of the unit battery cell is about 2.5V ~ 4.5V. Accordingly, when a higher output voltage is required, a plurality of battery cells are connected in series to form a battery pack. In addition, a plurality of battery cells may be connected in parallel to form a battery pack according to the charge/discharge capacity required for the battery pack. Accordingly, the number of battery cells included in the battery pack and an electrical connection type may be variously set according to a required output voltage and/or charge/discharge capacity.

On the other hand, as types of unit secondary battery cells, cylindrical, prismatic, and pouch-type battery cells are known. In the case of a cylindrical battery cell, a separator, which is an insulator, is interposed between the positive electrode and the negative electrode and wound to form an electrode assembly in the form of a jelly roll, which is then inserted into the battery can to configure the battery. In addition, a strip-shaped electrode tab may be connected to each of the uncoated regions of the positive electrode and the negative electrode, and the electrode tab electrically connects the electrode assembly and the externally exposed electrode terminal. For reference, the positive electrode terminal is a cap plate of a sealing body sealing the opening of the battery can, and the negative electrode terminal is the battery can. However, according to the conventional cylindrical battery cell having such a structure, since current is concentrated in the strip-shaped electrode tab coupled to the positive electrode uncoated region and/or the negative electrode uncoated region, resistance is large, heat is generated, and current collection efficiency is poor. There was a problem that it wasn't.

For small cylindrical battery cells with a form factor of 18650 or 21700, resistance and heat are not a big issue. However, when the form factor is increased to apply the cylindrical battery cell to an electric vehicle, a problem may arise in that the cylindrical battery cell ignites as a lot of heat is generated around the electrode tab during the fast charging process.

In order to solve this problem, a cylindrical battery having a structure in which a positive electrode uncoated region and a negative electrode uncoated region are positioned at the top and bottom of the jelly roll type electrode assembly, respectively, and a current collecting plate is welded to the uncoated region to improve current collection efficiency. A cell (so-called Tab-less cylindrical battery cell) is presented.

1 to 3 are views showing a manufacturing process of a tab-less cylindrical battery cell. 1 shows the structure of the electrode plate, FIG. 2 shows the winding process of the electrode plate, and FIG. 3 shows the process of welding the current collecting plate to the bent surface of the uncoated area.

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 on one long side along the winding direction (X). It includes an uncoated region 22 .

The electrode assembly (A) is manufactured by sequentially stacking the positive electrode plate 10 and the negative electrode plate 11 together with two separators 12 as shown in FIG. 2 and then winding them in one direction (X). At this time, the uncoated portions of the positive electrode plate 10 and the negative electrode plate 11 are disposed in opposite directions. The positions of the positive plate 10 and the negative plate 11 may be changed opposite to those shown.

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 bent toward the core. After that, the current collecting plates 30 and 31 are welded to the uncoated regions 10a and 11a, respectively, and are coupled thereto.

A separate electrode tab is not coupled to the positive uncoated region 10a and the negative uncoated region 11a, the current collecting plates 30 and 31 are connected to external electrode terminals, and a current path is used to wind the electrode assembly A. Since it is formed with a large cross-sectional area along the axial direction (refer to the arrow), there is an advantage in that the resistance of the battery cell can be lowered. This is because resistance is inversely proportional to the cross-sectional area of the path through which the current flows.

In the tab-less cylindrical battery cell, in order to improve the welding characteristics of the uncoated areas 10a and 11a and the current collecting plates 30 and 31, strong pressure is applied to the welding points of the uncoated areas 10a and 11a to make the uncoated area as flat as possible. (10a, 11a) should be bent.

When bending the uncoated areas 10a and 11a, a jig for pressing the uncoated areas 10a and 11a in the direction of the core of the electrode assembly A is used.

4 is an enlarged photograph of the bent shape of the uncoated area by cutting a portion of the bent portion in the longitudinal direction of the electrode assembly when the uncoated area is bent toward the core in the radial direction using a jig.

Referring to FIG. 4 , it can be seen that the bent shape of the uncoated area is not uniform, and the uncoated area is bent while irregularly deformed. In particular, the degree of deformation of the uncoated region increases toward the core of the electrode assembly. The reason is that the more the uncoated region is located closer to the core of the electrode assembly, the greater the stress applied by the jig.

If the uncoated region is bent irregularly, the bending surface is not flat, so it is difficult to weld the current collecting plate. In addition, if the uncoated area is irregularly deformed under the bent surface, the stress that caused the irregular deformation of the uncoated area may also affect a nearby separator, and the separator may be torn or the active material layer may be broken, resulting in an internal short circuit. When an internal short circuit occurs, an overcurrent flows and the temperature of the cylindrical battery cell rapidly rises, and as a result, the cylindrical battery cell may ignite or explode.

The present invention was devised under the background of the prior art as described above, and relates to a method for manufacturing an electrode assembly capable of uniformly making the bent shape of the uncoated region of a tab-less cylindrical battery cell, and this method An object of the present invention is to provide an electrode assembly manufactured by

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

Another technical object of the present invention is to provide an electrode assembly having improved energy density and reduced resistance.

Another technical object of the present invention is to provide a cylindrical battery cell including an electrode assembly having an improved structure, a battery pack including the same, and a vehicle including the battery pack.

The technical problems to be solved by the present invention are not limited to the above problems, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.

An electrode assembly according to an aspect of the present invention for achieving the above technical problem is a jelly roll type in which a first electrode current collector and a second electrode current collector having a sheet shape and a separator interposed therebetween are wound in one direction. In the electrode assembly, at least one of the first electrode current collector and the second electrode current collector includes an uncoated portion exposed to the outside of the separator along a longitudinal direction of the electrode assembly at a long side end, and the first electrode collector A cutting line is formed in the uncoated region of at least one of the entire uncoated region and the uncoated region of the second electrode current collector along the length direction of the electrode assembly, and the uncoated region in which the cutting line is formed is formed based on the cutting line. It is divided into a residual region that protrudes along the winding axis direction and a bending target region that is bent in a preset direction, and at least a portion of the uncoated region included in the bending target region includes a plurality of uncoated regions along the bending direction of the predetermined uncoated region. It is characterized in that it is bent so as to overlap with layers.

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

Preferably, the current collecting plate may be welded to the bent region of the uncoated region bent so as to overlap the plurality of layers of the bending target region.

Preferably, the cutting line may be formed by at least one cut.

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

In another aspect, after the current collecting plate is coupled to the uncoated portion of the bending target region, the total height of the current collecting plate and the uncoated portion corresponds to the height of the uncoated portion remaining in a protruding shape along a winding axis direction of the remaining region. can be

In another aspect, the sum of the height of the current collecting plate of the bending target area and the uncoated portion disposed thereunder may be the same as the height of the uncoated portion protruding from the remaining area.

Preferably, a gap may be formed between any one of the uncoated areas of the remaining area and the other uncoated area.

Preferably, the electrolyte may be configured to move through the gap.

In one aspect, the predetermined uncoated portion may be bent along the cutting line.

Preferably, the bending direction of the predetermined uncoated region may be a radial direction of the electrode assembly.

Preferably, the bending direction of the predetermined uncoated region may be a core direction of the electrode assembly.

Preferably, the shape of the bending target region may extend in a radial direction when viewed from a winding axis direction of the electrode assembly.

Preferably, the shape of the bending target region may be radially outward from the center of the core of the electrode assembly when viewed in the direction of the winding axis of the electrode assembly.

Preferably, the shape of the bending target region may be a radial shape extending outwardly in two or more directions from the center of the core of the electrode assembly when viewed in the direction of the winding axis of the electrode assembly.

Preferably, the shape of the bending target region may be a cross shape extending outwardly from the center of the core of the electrode assembly when viewed in the direction of the winding axis of the electrode assembly.

Preferably, the shape of the bending target region is a radial shape extending outwardly from the center of the core of the electrode assembly when viewed in the direction of the winding axis of the electrode assembly, and the cutting line is in the form of an arc toward the core of the electrode assembly. may be curved.

In one aspect, at least a portion of the uncoated region included in the bending target region may be bent toward the core of the electrode assembly.

Preferably, at least a portion of the uncoated region included in the bending target region may have a bent state to overlap with at least three or more layers in a radial direction of the electrode assembly.

Preferably, at least a portion of the uncoated region included in the bending target region may have a bent state to overlap with at least four or more layers in a radial direction of the electrode assembly.

Preferably, at least a portion of the uncoated region included in the bending target region may have a bent state so as to overlap with at least five or more layers in a radial direction of the electrode assembly.

In one aspect, an electrode plate is formed including the first electrode current collector and an active material layer formed on at least one surface of the first electrode current collector, and the electrode plate is a non-coated layer of the active material layer and the first electrode current collector. It may include an insulating coating layer formed at the boundary of the part, the insulating coating layer being exposed to the outside of the separator, and the lower end of the cutting line around the bending target area being spaced apart from the end of the insulating coating layer.

In another aspect, an electrode plate is formed including the second electrode current collector and an active material layer formed on at least one surface of the second electrode current collector, and the electrode plate is an uncoated layer of the active material layer and the second electrode current collector. It may include an insulating coating layer formed at the boundary of the part, the insulating coating layer being exposed to the outside of the separator, and the lower end of the cutting line around the bending target area being spaced apart from the end of the insulating coating layer.

A method of manufacturing an electrode assembly according to the present invention for achieving the above technical problem includes the steps of: (a) preparing a first electrode current collector and a second electrode current collector having a sheet shape and having an uncoated region on one side in a longitudinal direction; (b) stacking the first electrode current collector, the second electrode current collector, and the separator at least once so that a separator is interposed between the first electrode current collector and the second electrode current collector, wherein the first electrode collector forming the electrode current collector-separator stack so that the entire uncoated region and the uncoated region of the second electrode current collector are oppositely exposed along a longitudinal direction of the separator; (c) a jelly roll type so that the electrode collector-separator laminate is wound in one direction so that the uncoated portion of the first electrode collector and the uncoated portion of the second electrode collector are exposed in opposite directions along the winding axis direction forming an electrode assembly of (d) in at least one uncoated region of the uncoated region of the first electrode current collector and the uncoated region of the second electrode current collector, a residual region remaining in a protruding shape along the winding axis direction; forming a cutting line along a length direction of the electrode assembly to be divided into a bent target area to be bent; and (e) bending at least a portion of the uncoated region included in the bending target region to overlap in a plurality of layers along a bending direction of a predetermined uncoated region.

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

Preferably, the method may include welding the current collecting plate to the uncoated portion of the bending target region.

Preferably, the cutting line may include forming by a cutter that vibrates ultrasonically in a direction of a winding axis of the electrode assembly.

Preferably, the predetermined uncoated portion may include bending along the cutting line.

According to one aspect, a plurality of cutting lines in the bending target area may be formed in pairs and extend in a radial direction of the electrode assembly when viewed in a direction of a winding axis of the electrode assembly.

According to another aspect, a plurality of cutting lines of the bending target region may be formed and radially extending outward from the center of the core of the electrode assembly while forming two pairs of the plurality of cutting lines when viewed in the direction of the winding axis of the electrode assembly. have.

According to another aspect, a plurality of cutting lines of the bending target region may be provided, and each of the plurality of cutting lines may have an arc shape curved toward a center of the core of the electrode assembly when viewed from a winding axis direction of the electrode assembly.

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

Preferably, in step (e), at least a portion of the uncoated region included in the bending target region may be bent to overlap with at least three or more layers along a radial direction of the electrode assembly.

Preferably, in step (e), at least a portion of the uncoated region included in the bending target region may be bent to overlap with at least four layers in a radial direction of the electrode assembly.

Preferably, in step (e), at least a portion of the uncoated region included in the bending target region may be bent to overlap with at least five or more layers in a radial direction of the electrode assembly.

A cylindrical battery cell for achieving the above technical problem is a jelly roll type electrode assembly in which a first electrode current collector and a second electrode current collector having a sheet shape and a separator interposed therebetween are wound in one direction, wherein the At least one of the first electrode current collector and the second electrode current collector includes an uncoated region exposed to the outside of the separator in a longitudinal direction of the electrode assembly at a long side end thereof, and the uncoated region of the first electrode current collector and the A cutting line is formed on at least one uncoated portion of the uncoated portion of the second electrode current collector along a length direction of the electrode assembly, and the uncoated portion on which the cutting line is formed protrudes along a winding axis direction based on the cutting line. It is divided into a residual region remaining in a curved shape and a bending target region bent in a preset direction, and at least a portion of the uncoated region included in the bending target region is bent to overlap in a plurality of layers along the bending direction of the predetermined uncoated region. that the electrode assembly; a cylindrical battery can in which the electrode assembly is accommodated and electrically connected to the second electrode current collector; a sealing body sealing the open end of the battery can; an external terminal electrically connected to the first electrode current collector and having a surface exposed to the outside; and a current collecting plate welded to the bent surface of the uncoated region and electrically connected to any one of the battery can and the external terminal.

The technical problem can also be achieved by a battery pack including the above-described cylindrical battery cell and a vehicle including the same.

According to an aspect of the present invention, a cutting line is formed in the uncoated area corresponding to the edge of the bending target area by a cutter that vibrates ultrasonically in the winding axis direction of the electrode assembly, and the uncoated area is bent by bending the uncoated area of the bending target area. The flatness of the surface can be improved and the phenomenon that the uncoated area is irregularly bent under the bent surface can be alleviated.

In addition, the present invention may have various other effects, which will be described in each embodiment, or the corresponding description will be omitted for effects that can be easily inferred by those skilled in the art.

The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical spirit of the present invention together with the detailed description of the present invention to be described later, so that the present invention is described in such drawings should not be construed as being limited only to
1 is a plan view showing the structure of an electrode plate used for manufacturing a conventional tab-less cylindrical battery cell.
2 is a view showing the electrode plate winding process of the conventional tab-less cylindrical battery cell.
3 illustrates a process in which a current collecting plate is welded to a curved surface of an uncoated region in a conventional tab-less cylindrical battery cell.
4 is an enlarged photograph of the bent shape of the uncoated area by cutting a portion of the bent portion in the longitudinal direction of the electrode assembly when the uncoated area is bent toward the core in the radial direction using a jig.
5 is a plan view showing the structure of an electrode plate according to an embodiment of the present invention.
6 is a cross-sectional view taken along the Y-axis of a jelly roll type electrode assembly in which an electrode plate according to an embodiment of the present invention is applied to a first electrode current collector and a second electrode current collector.
7 is a plan view of a cutter used to form a cutting line in an uncoated area according to an embodiment of the present invention.
8 is a cross-sectional view taken along line A-A' of FIG. 7 .
9 is a configuration diagram schematically illustrating the configuration of an ultrasonic cutter according to an embodiment of the present invention.
10 to 12 are plan views of cutters according to various modifications of the present invention.
13 is a schematic perspective view illustrating a state after forming a cutting line on an uncoated region of an electrode assembly using a cutter according to an embodiment of the present invention.
FIG. 14 is a plan view of FIG. 13 .
15 is a schematic perspective view of a current collecting plate coupled to an upper side of the bent uncoated area after the uncoated area is bent along the cutting line in FIG. 13 .
FIG. 16 is a plan view of FIG. 15 .
17 is a plan view illustrating a state after forming a cutting line on an uncoated area of an electrode assembly using a cutter according to another embodiment of the present invention.
18 is a cross-sectional view taken along the Y-axis direction of a cylindrical battery cell according to an embodiment of the present invention.
19 is a cross-sectional view taken along the Y-axis direction of a cylindrical battery cell according to another embodiment of the present invention.
20 is a diagram schematically illustrating a configuration of a battery pack according to an embodiment of the present invention.
FIG. 21 is a view for explaining a vehicle including the battery pack of FIG. 20 .

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his invention. Based on the principle that it can be defined, it should be interpreted as meaning and concept consistent with the technical idea of the present invention.

Accordingly, the configuration shown in the embodiments and drawings described in the present specification is only the most preferred embodiment of the present invention and does not represent all the technical spirit of the present invention, so at the time of the present application, various It should be understood that there may be equivalents and variations.

In addition, in order to help the understanding of the invention, the accompanying drawings are not drawn to scale, but dimensions of some components may be exaggerated. Also, the same reference numerals may be assigned to the same components in different embodiments.

First, an electrode assembly according to an embodiment of the present invention will be described. The electrode assembly is a jelly roll type electrode assembly having a structure in which a first electrode current collector and a second electrode current collector having a sheet shape and a separator interposed therebetween are wound in one direction to form a winding center hole in a core.

Preferably, at least one of the first electrode current collector and the second electrode current collector includes an uncoated region on which an active material is not coated at a long side end in a winding direction. At least a portion of the uncoated region is used as an electrode tab by itself.

5 is a plan view showing the structure of the electrode plate 40 according to the embodiment of the present invention.

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 the uncoated portion 43 at the long side end in the winding direction (X). The uncoated area 43 is an area where the active material is not coated. An insulating coating layer 44 may be formed at a boundary between the active material layer 42 and the uncoated region 43 . At least a portion of the insulating coating layer 44 is formed to overlap the boundary between the active material layer 42 and the uncoated region 43 . The insulating coating layer 44 may include a polymer resin, and may include an inorganic filler such as Al ₂ O ₃ . The polymer resin may have a porous structure. The polymer resin is not particularly limited as long as it is an insulating material. The polymer resin may be polyolefin, polyimide, polyethylene terephthalate, polybutylene fluoride, or the like, but the present invention is not limited thereto.

Preferably, a portion of the uncoated region 43 adjacent to the core side may be cut through a notching process. In this case, even when the uncoated area 43 is bent toward the core, the core of the electrode assembly is not blocked by the bent portion of the uncoated area 43 . For reference, the core is provided with a cavity formed when the bobbin used for winding the electrode assembly is removed. The cavity may be utilized as an electrolyte injection passage or a passage for inserting a welding jig. In the drawing, the dashed-dotted line indicates the lowest position at which the uncoated region 43 is bent. Bending of the uncoated region 43 is performed at a dot-and-dash line or a position higher than that.

The cutting portion B of the uncoated region 43 forms a plurality of winding turns in a 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 cutting portion B and the bending length h of the uncoated region 43 may be adjusted so that the predetermined width is equal to or greater than the bending length h of the uncoated region 43 . . Then, even if the uncoated region 43 is bent, the core of the electrode assembly is not blocked.

In order to prevent damage to the active material layer 42 and/or the insulating coating layer 44 when the cutting part B of the uncoated part 43 is formed, a gap G is formed between the cut line and the insulating coating layer 44 . It is preferable to put The gap (G) is preferably 0.2 to 4 mm. When the gap G is adjusted to the corresponding numerical range, it is possible to prevent the active material layer 42 and/or the insulating coating layer 44 from being damaged due to the cutting tolerance when the uncoated area 43 is cut.

In a specific example, when the electrode plate 40 is used to manufacture an electrode assembly of a cylindrical automobile 900 having a form factor of 46800, the width d of the uncoated area cutting portion B depends on the diameter of the electrode assembly core. It can be set to 180 to 350 mm.

Meanwhile, when the core of the electrode assembly is not used in an electrolyte injection process, a welding process, etc., the cutting part B of the uncoated part 43 may not be formed.

The electrode plate 40 of the above-described embodiment may be applied to the first electrode current collector and/or the second electrode current collector included in the jelly roll type electrode assembly. In addition, when the electrode structure of the embodiment is applied to any one of the first electrode current collector and the second electrode current collector, the conventional electrode plate structure ( FIG. 1 ) may be applied to the other one. In addition, the electrode plate structures applied to the first electrode current collector and the second electrode current collector may not be the same but may be different from each other.

In the present invention, the positive active material coated on the first electrode collector and the negative active material coated on the second electrode collector may be used without limitation as long as the active material is known in the art.

In one example, the positive active material has the general formula A[A _x M _y ]O _2+z (A includes at least one element of Li, Na, and K; M is Ni, Co, Mn, Ca, Mg, Al, at least one element selected from 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; stoichiometric coefficients x, y and z are selected such that the compound remains electrically neutral).

In another example, the positive active material includes an alkali metal compound xLiM ¹ O ₂ (1x)Li ₂ M ² O ₃ (M ¹ comprising at least one element having an average oxidation state 3; M; ² includes at least one element having an average oxidation state 4; 0≤x≤1).

In another example, the positive active material may have the general formula Li _a M ¹ _x Fe _1x M ² _y P _1y M ³ _z O _4z (M ¹ is Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, At least one element selected from Nd, Al, Mg and Al M ² is Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, Al, As, Sb, Si , Ge, contains at least one element selected from V and S; M ³ contains a halogen element optionally including F; 0 < a ≤ 2, 0 ≤ x ≤ 1, 0 ≤ y < 1, 0 ≤ z <1; stoichiometric coefficients a, x, y and z are chosen such that the compound remains electrically neutral), or Li ₃ M ₂ (PO ₄ ) ₃ [M is Ti, Si, Mn, Fe, Co, V, Cr , Mo, Ni, Al, including at least one element selected from Mg and Al] may be a lithium metal phosphate represented by.

Preferably, the positive electrode active material may include primary particles and/or secondary particles in which the primary particles are aggregated.

In one example, the negative active material may be a carbon material, lithium metal or a lithium metal compound, silicon or a silicon compound, tin or a tin compound. A metal oxide having a potential of less than 2V, such as TiO ₂ and SnO ₂ , may also be used as the negative electrode active material. As the carbon material, both low-crystalline carbon, high-crystalline carbon, and the like may be used.

The separator is a porous polymer film, for example, a porous polymer film made of a polyolefin-based polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene/butene copolymer, an ethylene/hexene copolymer, or an ethylene/methacrylate copolymer. Or they can be used by laminating them. As another example, the separator may be a conventional porous nonwoven fabric, for example, a nonwoven fabric made of high melting point glass fiber, polyethylene terephthalate fiber, or the like.

At least one surface of the separator may include a coating layer of inorganic particles. It is also possible that the separation membrane itself is made of a coating layer of inorganic particles. Particles constituting the coating layer may have a structure combined with a binder so that an interstitial volume exists between adjacent particles.

The inorganic particles may be formed of an inorganic material having a dielectric constant of 5 or more. As a non-limiting example, the inorganic particles are Pb(Zr,Ti)O ₃ (PZT), Pb _1x La _x Zr _1y Ti _y O ₃ (PLZT), PB(Mg ₃ Nb _2/3 )O ₃ PbTiO ₃ ( PMNPT), BaTiO ₃ , hafnia(HfO ₂ ), SrTiO ₃ , TiO ₂ , Al ₂ O ₃ , ZrO ₂ , SnO ₂ , CeO ₂ , MgO, CaO, ZnO and Y ₂ O ₃ At least one selected from the group consisting of material may be included.

The electrode assembly according to the embodiment is a jelly roll type electrode assembly 50 in which the electrode plate 40 of the embodiment is applied to a first electrode current collector and a second electrode current collector.

6 is a cross-sectional view taken along the Y axis of a jelly roll type 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.

The positive electrode plate 45 may have an active material layer formed on at least one surface of the first electrode current collector, and the negative electrode plate 47 may have an active material layer formed on at least one surface of the second electrode current collector.

Referring to FIG. 6 , the electrode assembly 50 may be manufactured by the winding method described with reference to FIG. 2 . The uncoated region 43a protruding upward of the electrode assembly 50 extends from the positive electrode plate 45 . The uncoated region 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 Y-axis direction length of the active material coating region of the positive electrode plate 45 may be smaller than the Y-axis direction length of the active material coating region of the negative electrode plate 47 . Accordingly, the active material coating region of the negative electrode plate 47 may extend longer in the Y-axis direction than the active material coating region of the positive electrode plate 45 .

Preferably, the insulating coating layer 44 formed at the boundary between the active material region of the positive electrode plate 45 and the negative electrode plate 47 and the uncoated regions 43a and 43b extends to the end of the separator 46 or may be exposed to the outside from the end. have. When the insulating coating layer 44 is exposed to the outside of the separator 46 , it may serve to support the bending point when the uncoated regions 43a and 43b are bent. When the bending point is supported, the stress applied to the active material layer 42 and the separator 46 when the uncoated regions 43a and 43b are bent is relieved. In addition, the insulating coating layer 44 may 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 bending target region D may have a shape protruding to the outside of the insulating coating layer 44 .

The positive electrode plate 45 of the electrode plate 40 includes a first electrode current collector and an active material coating layer formed on at least one surface thereof, and the thickness of the first electrode current collector (uncoated portion 43a) may be 180 to 220 μm. The negative electrode plate 47 includes a second electrode current collector and an active material coating layer formed on at least one surface thereof, and the thickness of the second electrode current collector (uncoated portion 43b) may be 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.

In the winding structure of the positive electrode plate 45 , an interval between the uncoated regions 43a positioned at adjacent winding turns may be 350 to 380 μm. In addition, in the winding structure of the negative electrode plate 47 , the interval between the uncoated regions 43b positioned at adjacent winding turns may be 350 to 380 μm.

In the electrode assembly 50 , the number of turns of the positive electrode plate 45 varies depending on the form factor of the cylindrical vehicle 900 , and may be 48 to 56 . The number of turns of the negative electrode plate 47 also varies depending on the form factor of the cylindrical vehicle 900 and may be 48 to 56.

The uncoated areas 43a and 43b are longer than the uncoated areas applied to the design of the compact cylindrical vehicle 900 . Preferably, the uncoated regions 43a and 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, optionally 12 mm or more.

7 and 8 are views showing the structure of the cutter 60 used to form the cutting line 100 on the uncoated areas 43a and 43b according to an embodiment of the present invention. It is a plan view, and FIG. 8 is a cross-sectional view taken along line A-A' of FIG. 7 .

7 and 8 , the cutter 60 according to the embodiment includes a cutter body 61 and a plurality of cutter knives 62 , and a recess groove 63 is provided at the center of the cutter body 61 . can be provided. Preferably, the cutter body 61 may be coupled to the horn 64 of the ultrasonic cutter. The ultrasonic cutter will be described later.

Preferably, the cutter body 61 is made of a metal material, for example, an aluminum alloy, a titanium alloy, carbon steel, or the like. The cutter knife 62 is made of a metal material, for example, carbon steel, ferroalloy, high-speed steel, cast alloy, cermet, cubic boron nitride, ceramic, diamond, or the like. is done

A lower end of the plurality of cutter knives 62 may be embedded in the cutter body 61 . Alternatively, the lower end of the cutter knife 62 may be welded to the cutter body 61 after being inserted into a groove formed in the cutter body 61 .

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

Preferably, the plurality of cutter knives 62 may be paired by two and extend in parallel outward from the center of the cutter body 61 . The area between the two cutter knives 62 extending in parallel corresponds to the bending target area D of the uncoated areas 43a and 43b.

The plurality of cutter knives 62 are formed in pairs and extend radially with respect to the center of the cutter body 61 , and the angle between the pairs of cutter knives 62 may be substantially the same.

In one example, the total number of cutter knives 62 may be eight. In this case, the radially extending pairs of cutter knives 62 form an angle of 90 degrees with each other. As will be described later, the radially extending shape of the pair of cutter knives 62 is of course capable of various modifications.

In an embodiment of the present invention, the cutter 60 may be included in an ultrasonic cutter.

9 is a configuration diagram schematically showing the configuration of the ultrasonic cutter 70 according to the embodiment of the present invention.

Referring to FIG. 9 , the ultrasonic cutter 70 according to the embodiment may include a converter 71 , a booster 72 , a horn 73 , and a cutter 74 .

The converter 71 generates ultrasonic vibrations. The converter 71 may include a ceramic vibrator to generate ultrasonic waves. The booster 72 amplifies the ultrasonic wave generated by the converter 71 and transmits it to the horn 73 . The horn 73 transmits the ultrasonic vibration amplified by the booster 72 to the cutter 74 . Preferably, the cutter 74 may be the cutter 60 described above. In this case, the lower portion of the cutter body 61 of the cutter 60 may be coupled to the horn 73 by bolt/nut fastening, riveting, welding, or the like. When the cutter 74 moves the coupled horn 73 in the cutting direction while contacting the work piece, the work piece is cut by the ultrasonically vibrating cutter 74 .

Although not shown, the ultrasonic cutter 70 is a mechanical and/or electronic mechanism for linear and/or rotational movement of the horn 73, comprising: a station to which a workpiece is fixed; and/or servo motors and/or linear motors and/or air cylinders that support linear and/or rotational motion of the horn 73; and/or a driving source thereof; and/or an electronic control device thereof, and/or the like.

The above-described configuration of the ultrasonic cutter 70 is well known in the art, and it is the present invention that various parts necessary for the linear movement and/or rotational movement of the horn 73 can be additionally coupled to the ultrasonic cutter 70 . It is obvious to those of ordinary skill in the technical field to which this belongs.

On the other hand, those skilled in the art to which the present invention pertains will understand that the structure of the cutter 60 can be modified in various forms.

10 to 12 are plan views of cutters (60a, 60b, 60c) according to various modifications of the present invention.

10 to 12 , the cutter 60a has a structure in which a pair of cutter knives 62 extend radially while forming a 120 degree angle with each other. In addition, the cutter 60b has a structure in which a pair of cutter knives 62 extend radially while forming 180 degrees with each other.

In another modified example, the cutter 60c may include a cutter knife 62 having an arc shape recessed toward the center of the cutter body 61 . The arc shape of the cutter knife 62 may be point-symmetrical, left-right symmetry, or vertical symmetry with respect to the center of the cutter body 61 . Although the cutter knives 62 have an arc shape, they have a radially extending structure 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, the cutter knives 62 are preferably arranged at equal intervals in the circumferential direction of the cutter body 61 .

The cross-sectional structure of the cutter knives 62 included in the cutters 60a, 60b, and 60c of various embodiments is substantially the same as that shown in FIG. 8, and can be used as the cutter 74 of the ultrasonic cutter 70 do. In this case, the cutter body 61 may be coupled to the horn 73 of the ultrasonic cutting key 70 .

Meanwhile, according to the embodiment of the present invention, the uncoated regions 43a and 43b of the electrode assembly 50 have cutting lines 100 formed along the length direction of the electrode assembly by the cutters 60 , 60a , 60b and 60c. Thereafter, it may be divided into a residual region R remaining in a protruding shape along the winding axis direction based on the cutting line 100 and a bending target region D bent in a preset direction.

Preferably, the bending direction of the predetermined uncoated areas 43a and 43b may be the radial direction of the electrode assembly 50 . Also, preferably, the bending direction of the predetermined uncoated areas 43a and 43b may be the core direction of the electrode assembly 50 .

13 is a schematic perspective view illustrating a state after forming a cutting line 100 on the uncoated regions 43a and 43b of the electrode assembly 50 using the cutter 60 according to an embodiment of the present invention, and FIG. 14 . is a plan view of FIG. 13 .

13 and 14 , at least one uncoated region of the uncoated region 43a of the first electrode current collector and the uncoated region 43b of the second electrode current collector has a cutting line 100 along the length direction of the electrode assembly. ) is formed, and the uncoated regions 43a and 43b have a residual region R remaining in a protruding shape along the winding axis direction with respect to the cutting line 100 , and a bending target region D bent in a preset direction. ) are separated. That is, the uncoated regions 43a and 43b of the residual region R are maintained without being bent, and the uncoated regions 43a and 43b of the bending target region D are bent in a preset direction.

Preferably, the uncoated regions 43a and 43b are cut along the winding axis direction Y of the electrode assembly 50 to form the cutting line 100 .

Preferably, the cutting line 100 may be formed by the cutter 60 oscillating ultrasonic waves in the direction of the winding axis of the electrode assembly 50 .

First, while the cutter 60 is vibrated with ultrasonic waves, 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, ground direction) to move the uncoated area 43a , 43b) is cut to a predetermined depth to form a cutting line 100 at the edge of the bending target area (D). In addition, the predetermined uncoated areas 43a and 43b may be bent along the cutting line 100 .

The bending target area D corresponds to an area bent in multiple layers for welding with the current collecting plate 80 . The cutting line 100 corresponds to a region in which the upper portions of the uncoated regions 43a and 43b are cut in a line slit shape. Preferably, the cutting depth may be 2 to 10 mm, and the lowest point where vertical cutting using the cutter 60 ends is higher than the end of the insulating coating layer 44 exposed to the outside of the separator 46 (arrow in FIG. 6 ) mark point).

The cutting line 100 may be formed by at least one cut. For example, referring to FIG. 13 , the cutting line 100 may be formed by one cutting using the cross-shaped cutter of FIG. 7 . Alternatively, although not shown in the drawing, the cutting line 100 may be formed by cutting each of the horizontal and vertical directions once each using a cutter formed in a pair of vertical lines. Alternatively, although not shown in the drawings, the cutting line 100 may be formed by eight cuttings using one cutter, or another method is possible.

FIG. 15 is a schematic perspective view of the uncoated areas 43a and 43b being bent along the cutting line 100 in FIG. 13 , and a current collecting plate coupled to the upper side of the bent uncoated areas 43a and 43b, and FIG. 16 is FIG. 15 is a floor plan.

In FIG. 13 , when the uncoated areas 43a and 43b of the bending target area D are bent, grooves are formed along the bending direction, and as shown in FIGS. 15 and 16 , a current collector having a shape corresponding to the groove shape of the bending target area D The plate 80 may be coupled to the uncoated areas 43a and 43b of the bending target area D. In this case, the current collecting plate 80 may be coupled to the uncoated regions 43a and 43b of the bending target region D by welding. However, the coupling method of the current collecting plate 80 is not limited to welding.

When the cutting line 100 is formed in the uncoated areas 43a and 43b as described above, flatness is improved when the uncoated areas 43a and 43b are bent along the bending target area D, and accordingly, the uncoated areas 43a and 43b. ) can make the bending shape uniform. In addition, when the bent shape of the uncoated regions 43a and 43b becomes uniform, there is an effect of improving weldability.

15 , after the current collecting plate 80 is coupled to the uncoated areas 43a and 43b of the bending target area D, the total height h1 of the current collecting plate 80 and the uncoated areas 43a and 43b is , may correspond to the height h2 of the uncoated regions 43a and 43b remaining in a protruding shape along the winding axis direction of the residual region R. For example, the total height h1 of the current collecting plate 80 and the uncoated areas 43a and 43b of the bending target area D is the height h2 of the protruding uncoated areas 43a and 43b of the remaining area R. ) and may be formed to be similar or identical to

A gap g may be formed between any one uncoated area among the uncoated areas 43a and 43b of the remaining area R and the other uncoated area. And, the electrolyte may be configured to move through the gap. The uncoated areas 43a and 43b of the bending target area D are bent in a preset direction, and since there is almost no gap between any one uncoated area and the other uncoated area of the bending target area D, it is difficult for the electrolyte to move. . However, the uncoated regions 43a and 43b of the residual region R are not bent and are oriented in the vertical direction, so that between the uncoated region of one of the uncoated regions 43a and 43b of the residual region R and the other uncoated region. A gap is formed in the gap, and since the electrolyte flows through the gap, the wetting of the electrolyte is improved.

17 is a view illustrating a state after forming the cutting line 100 on the uncoated regions 43a and 43b of the electrode assembly 50 using the cutter 60c according to another embodiment of the present invention.

Referring to FIG. 17 , first, while the cutter 60c vibrates with ultrasonic waves, the cutter knife 62 faces the upper surface of the electrode assembly 50 and the cutter 60c is moved along the winding axis direction (Y axis, ground direction). The cutting line 100 is formed at the edge of the bending target area D by moving the upper portions of the uncoated areas 43a and 43b to a predetermined depth. The cutting line 100 has an arc shape curved toward the center of the core of the electrode assembly 50 . Accordingly, the bending target area D has a cross shape, but an edge has an arc shape.

The bending target area D corresponds to an area bent in multiple layers for welding with the current collecting plate 80 . The cutting line 100 corresponds to a region formed on the uncoated regions 43a and 43b, for example, like a cut. Preferably, the cutting depth may be 2 to 10 mm, and the lowest point where vertical cutting using the cutter 60c ends is higher than the end of the insulating coating layer 44 exposed to the outside of the separator 46 (arrow in FIG. 6 ) mark point).

Preferably, as shown in FIG. 5 , since the uncoated region 43 near the core of the electrode assembly 50 has a lower height than the uncoated region 43 in other portions, the bending target region D may not be formed. have. The shape of the bending target area D may vary. In one example, the shape of the bending target region D may extend in a radial direction when viewed from the winding axis direction of the electrode assembly 50 . In another example, the shape of the bending target region D may be radially outwardly from the center of the core of the electrode assembly 50 when viewed in the direction of the winding axis of the electrode assembly 50 . In another example, the shape of the bending target region D may be a radial shape extending outwardly in two or more directions from the center of the core of the electrode assembly 50 when viewed in the direction of the winding axis of the electrode assembly 50 . In another example, the shape of the bending target region D may be a cross shape extending outwardly from the center of the core of the electrode assembly 50 when viewed in the direction of the winding axis of the electrode assembly 50 . In another example, the shape of the bending target region D is a radial shape extending outwardly from the center of the core of the electrode assembly 50 when viewed in the direction of the winding axis of the electrode assembly 50 , and the cutting line 100 is a circular arc. may be curved toward the core of the electrode assembly 50 in the form of

Referring again to FIG. 13 , according to another aspect of the present invention, the bending target area D formed by cutting the uncoated areas 43a and 43b of the electrode assembly 50 along the cutting line 100 is a predetermined uncoated area. (43a, 43b) may be bent along the bending direction.

Preferably, the bending direction of the predetermined uncoated areas 43a and 43b is the radial direction of the electrode assembly 50 . More preferably, the bending target area D may be bent along the radial direction of the electrode assembly 50 . More preferably, the bending target region D may be bent from the outer shell of the electrode assembly 50 toward the core.

Preferably, the uncoated regions 43a and 43b included in the bending target region D may be bent along the radial direction of the electrode assembly 50 , preferably from the outer shell toward the core.

Preferably, by adjusting the length of the uncoated area to be bent in the range of 2 to 10 mm, at least 3 or more, or at least 4 or more, or at least 5 or more layers of the uncoated area to be bent along the bending direction of the electrode assembly 50 are It may be overlapped along the winding axis (Y-axis) direction.

The bending target area D has a structure extending radially along the bending direction. In addition, the uncoated portion of the bending target region D has a narrow width. Accordingly, when the uncoated portion of the bending target area D is bent along the radial direction of the electrode assembly A, the bending is uniformly performed. In addition, since the width of the uncoated portion to be bent is narrow, the flatness of the bent surface is improved as the uncoated portions are overlapped in multiple layers. In addition, when the current collecting plate 80 is welded to the curved surface having improved flatness, welding power can be increased to sufficiently increase welding strength, and resistance characteristics of the welding interface can be improved.

The electrode assembly 50 according to the embodiment of the present invention may be applied to a jelly roll type cylindrical automobile 900 .

Preferably, the cylindrical vehicle 900 has, for example, a ratio of form factor (defined as the diameter of the cylindrical vehicle 900 divided by the height, i.e., the ratio of the height H to the diameter Φ) is greater than approximately 0.4. It may be a large cylindrical automobile 900 .

Here, the form factor means values indicating the diameter and height of the cylindrical vehicle 900 . The cylindrical vehicle 900 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 numerical value representing the form factor, the first two numbers indicate the diameter of the cell, the next two numbers indicate the height of the cell, and the last number 0 indicates that the cell has a circular cross section. If the height of the cell exceeds 100mm, the last digit 0 can be omitted because three digits are required to indicate the height.

When an electrode assembly having a tab-less structure is applied to the cylindrical automobile 900 having a form factor ratio of greater than 0.4, the uncoated region is easily torn due to a large stress applied in the radial direction when the uncoated region is bent. In addition, when the current collecting plate 80 is welded to the bent surface of the uncoated region, the number of overlapping layers in the uncoated region must be sufficiently increased in order to sufficiently secure welding strength and lower resistance. This requirement can be achieved by the electrode plate and the electrode assembly according to the embodiments (modified examples) of the present invention.

The automobile 900 according to an embodiment of the present invention may be a cylindrical automobile 900 having a substantially cylindrical cell, a diameter of about 46 mm, a height of about 110 mm, and a form factor ratio of 0.418.

The automobile 900 according to another embodiment may be a cylindrical automobile 900 having an approximately cylindrical cell, a diameter of approximately 48 mm, a height of approximately 75 mm, and a form factor ratio of 0.640.

The automobile 900 according to another embodiment may be a cylindrical automobile 900 having an approximately cylindrical cell, a diameter of approximately 48 mm, a height of approximately 110 mm, and a form factor ratio of 0.418.

The automobile 900 according to another embodiment may be a cylindrical automobile 900 having a substantially cylindrical cell, a diameter of about 48 mm, a height of about 80 mm, and a form factor ratio of 0.600.

The automobile 900 according to another embodiment may be a cylindrical automobile 900 having an approximately cylindrical cell, a diameter of approximately 46 mm, a height of approximately 80 mm, and a form factor ratio of 0.575.

Conventionally, automobiles 900 having a form factor ratio of approximately 0.4 or less have been used. That is, conventionally, for example, 18650 cells, 21700 cells, and the like have been used. For an 18650 cell, its diameter is approximately 18 mm, its height is approximately 65 mm, and the form factor ratio is 0.277. For a 21700 cell, its diameter is approximately 21 mm, its height is approximately 70 mm, and the form factor ratio is 0.300.

Hereinafter, a cylindrical vehicle 900 according to an embodiment of the present invention will be described in detail.

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

Referring to FIG. 18 , the cylindrical battery cell 190 according to an embodiment of the present invention includes an electrode assembly 110 including a first electrode current collector, a separator, and a second electrode current collector wound in a jelly roll shape, and an electrode. It includes a battery can 142 for accommodating the assembly 110 and a sealing body 143 for sealing the open end of the battery can 142 . The electrode assembly 110 has the structure of the above-described embodiment.

The battery can 142 is a cylindrical container in which an opening is formed at the upper side. The battery can 142 is made of a metal material having conductivity, such as aluminum, steel, stainless steel, or the like. The battery can 142 accommodates the electrode assembly vehicle 900 in the inner space through the upper opening and also accommodates the 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.

The electrolyte may be a salt having a structure such as A ⁺ B-. Here, A ⁺ includes an ion composed of an alkali metal cation such as Li ⁺ , Na ⁺ , K ⁺ or a combination thereof. And B- is F-, Cl-, Br-, I-, NO _3- , N(CN) _2- , BF _4- , ClO _4- , AlO _4- , AlCl _4- , PF _6- , SbF _6- , AsF _6- , BF ₂ C ₂ O _4- , BC ₄ O _8- , (CF ₃ ) ₂ PF _4- , (CF ₃ ) ₃ PF ₃ ^- , (CF ₃ ) ₄ PF _2- , (CF ₃ ) ₅ PF-, (CF ₃ ) ₆ P-, CF ₃ SO _3- , C ₄ F ₉ SO _3- , CF ₃ CF ₂ SO _3- , (CF ₃ SO ₂ ) ₂ N-, (FSO ₂ ) ₂ N - _, CF ₃ CF ₂ (CF ₃ ) ₂ CO-, (CF ₃ SO ₂ ) ₂ CH-, (SF ₅ ) ₃ C-, (CF ₃ SO ₂ ) ₃ C-, CF ₃ (CF ₂ ) ₇ SO _3- , CF ₃ CO ₂ - , CH ₃ CO ₂ ^- ,SCN- and (CF ₃ CF ₂ SO ₂ ) ₂ N- It includes any one or more anions selected from the group consisting of.

The electrolyte can also be used by dissolving it in an organic solvent. As an organic solvent, 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 (N-methyl- 2-pyrrolidone, NMP), ethyl methyl carbonate (EMC), gamma butyrolactone (γ-butyrolactone), or a mixture thereof may be used.

The electrode assembly 110 may have a jelly roll shape. As shown in FIG. 2 , the electrode assembly 110 is an electrode plate formed by sequentially stacking a lower separator, a first electrode current collector, an upper separator, and a second electrode current collector at least once. It can be manufactured by winding on the basis of (C).

An uncoated region 146a of the first electrode current collector and an uncoated region 146b of the second electrode current collector protrude from the upper and lower portions of the electrode assembly 110 , respectively.

The sealing body 143 seals the open end of the battery can 142 , and provides airtightness between the cap plate 143a and the cap plate 143a and the battery can 142 , and includes a first gasket 143b having insulation properties. and a connection plate 143c electrically and mechanically coupled to the cap plate 143a.

The cap plate 143a is a component made of a conductive metal material and covers the upper opening of the battery can 142 . The cap plate 143a is electrically connected to the uncoated portion 146a of the first electrode current collector, and is electrically insulated from the battery can 142 through a first gasket 143b. Accordingly, the cap plate 143a may function as a first electrode terminal of the cylindrical battery cell 140 .

The cap plate 143a is seated on the beading part 147 formed on the battery can 142 , and is fixed by the crimping part 148 . A first gasket 143b is interposed between the cap plate 143a and the crimping part 148 to secure the airtightness of the battery can 142 and to electrically insulate the battery can 142 and the cap plate 143a. can The cap plate 143a may include a protrusion 143d protruding upward from the center thereof.

The battery can 142 is electrically connected to the uncoated region 146b of the second electrode current collector. Accordingly, the battery can 142 has the same polarity as the second electrode current collector.

The battery can 142 has a beading part 147 and a crimping part 148 at the top. The beading portion 147 is formed by press-fitting the outer peripheral surface of the battery can 142 . The beading part 147 prevents the electrode assembly 110 accommodated in the battery can 142 from escaping through the top opening of the battery can 142 , and may function as a support part on which the sealing body 143 is seated. .

The crimping portion 148 is formed on the beading portion 147 . The crimping part 148 has a shape that is extended and bent so as to surround the outer peripheral surface of the cap plate 143a disposed on the beading part 147 and a portion of the upper surface of the cap plate 143a.

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 .

The first current collecting plate 144 is coupled to the upper portion of the electrode assembly 110 . The first current collecting plate 144 is made of a metal material having conductivity, such as aluminum, copper, nickel, etc., and the uncoated region 146a included in the bending target region D of the first electrode current collector is the electrode assembly 110 . It is electrically connected to the curved surface formed while being bent in the radial direction, preferably toward the core center (C). A lead 149 may be connected to the first current collecting plate 144 . The lead 149 may extend upwardly of the electrode assembly 110 and may be coupled to the connection plate 143c or may be directly coupled to the lower surface of the cap plate 143a. The lead 149 and other components may be coupled through welding.

Preferably, the first current collecting plate 144 may be integrally formed with the lead 149 . In this case, the lead 149 may have an elongated plate shape extending outward from the center of the first current collecting plate 144 .

The coupling between the bent surface of the uncoated region 146a and the first current collecting plate 144 may be performed, for example, by laser welding. Laser welding may be performed by partially melting the current collector plate base material. Laser welding can be replaced by resistance welding, ultrasonic welding, spot welding, and the like.

A second current collecting plate 145 may be coupled to a lower surface of the electrode assembly 110 . On one surface of the second current collecting plate 145 , the uncoated portion 146b of the second electrode current collector included in the bending target region D protruding downward of the electrode assembly 110 is disposed in the radial direction of the electrode assembly 110 . , Preferably, it is coupled by welding to the bent surface formed while bending toward the core center (C), and the opposite side may be coupled by welding on the inner bottom surface of the battery can 142 . The coupling structure between the second current collecting plate 145 and the uncoated region 146b of the second electrode current collector is substantially the same as the coupling structure between the first current collecting plate 144 and the uncoated region 146a of the first electrode current collector. may be the same.

The insulator 146 may cover the first current collecting plate 144 . The insulator 146 may cover the first current collecting plate 144 from the upper surface of the first current collecting plate 144 , thereby preventing direct contact between the first current collecting plate 144 and the inner peripheral surface of the battery can 142 . .

The insulator 146 includes a lead hole 151 so that a lead 149 extending upwardly from the first current collecting plate 144 can be withdrawn. The lead 149 is drawn upward through the lead hole 151 and is coupled to the lower surface of the connection plate 143c or the lower surface of the cap plate 143a.

The peripheral region of the insulator 146 may be interposed between the first current collecting plate 144 and the beading portion 147 to fix the electrode assembly 110 and the first current collecting plate 144 . Accordingly, in the assembly of the electrode assembly 110 and the first current collecting plate 144 , the movement of the battery cell 190 in the height direction is limited, so that the assembly stability of the battery cell 190 may be improved.

The insulator 146 may be made of an insulating polymer resin. In one example, the insulator 146 may be made of polyethylene, polypropylene, polyimide, or polybutylene terephthalate.

The battery can 142 may further include a venting part 152 formed on a lower surface thereof. The venting part 152 corresponds to a region having a thinner thickness compared to a peripheral region of the lower surface of the battery can 142 . The venting part 152 is structurally weak compared to the surrounding area. Accordingly, when an abnormality occurs in the cylindrical battery cell 190 and the internal pressure increases to a certain level or more, the venting part 152 may rupture and the gas generated inside the battery can 142 may be discharged to the outside. The venting part 152 may be a notch groove formed on an upper surface and/or a lower surface of the bottom of the battery can 142 . When the notch grooves are simultaneously formed on the upper and lower surfaces of the bottom of the battery can 142 , the positions thereof preferably correspond to each other.

The venting part 152 may be formed continuously or discontinuously while drawing a circle on the lower surface of the battery can 142 . In a modified example, the venting part 152 may be formed in a straight pattern or other pattern.

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

Referring to FIG. 19 , the cylindrical battery cell 200 has substantially the same structure as the cylindrical battery cell 190 shown in FIG. 18 , and is different in that the structure except for the electrode assembly is changed. .

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

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

The terminal insertion part 172b may pass through an approximately central portion of the closed surface of the battery can 171 to be electrically connected to the uncoated part 146a of the first electrode current collector. A portion electrically connected to the terminal insertion portion 172b is among the bent surfaces formed while the uncoated portion 146a of the first electrode current collector included in the bending target region D protruding upward of the electrode assembly 110 is bent. is the center

Here, the bottom surface of the terminal insertion part 172b is substantially flat and may be welded to the center of the first current collecting plate 144 connected to the uncoated part 146a of the first electrode current 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 an upper portion of the first current collecting plate 144 and an upper edge portion of the electrode assembly 110 . Accordingly, it is possible to prevent the uncoated portion 146a of the electrode assembly 110 from contacting the inner surface of the battery can 171 having a different polarity to cause a short circuit. Preferably, the terminal insertion portion 172b of the rivet terminal 172 may penetrate the insulating cap 174 and be welded to the first current collecting plate 144 .

The terminal insertion part 172b may be riveted to the inner surface of the battery can 171 . That is, the end edge of the terminal insertion part 172b may be bent toward the inner surface of the battery can 171 by being pressed by a caulking jig. The maximum diameter of the end of the terminal insertion part 172b may be greater than the maximum diameter of the through hole of the battery can 171 .

The second gasket 173 is interposed between the battery can 171 and the rivet terminal 172 to prevent the battery can 171 and the rivet terminal 172 having opposite polarities from electrically contacting each other. Accordingly, the upper surface of the battery can 171 having a substantially flat shape may function as the second electrode terminal of the cylindrical battery cell 200 .

The second gasket 173 includes a gasket exposed portion 173a and a gasket insertion portion 173b. The gasket exposed portion 173a is interposed between the terminal exposed portion 172a of the rivet terminal 172 and the battery can 171 . The gasket insertion part 173b is interposed between the terminal insertion part 172b of the rivet terminal 172 and the battery can 171 . The gasket insertion part 173b may be deformed together during riveting of the terminal insertion part 172b to be in 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.

The gasket exposed portion 173a of the second gasket 173 may extend to cover the outer peripheral surface of the terminal exposed portion 172a of the rivet terminal 172 . When the second gasket 173 covers the outer circumferential surface of the rivet terminal 172 , a short circuit occurs in the process of coupling an electrical connection component such as a bus bar to the upper surface and/or the rivet terminal 172 of the battery can 171 . it can be prevented Although not shown in the drawings, the gasket exposed portion 173a may have an extended shape to cover a portion of the upper surface as well as the outer peripheral surface of the terminal exposed portion 172a.

When the second gasket 173 is made of a polymer resin, the second gasket 173 may be coupled to the battery can 171 and the rivet terminal 172 by thermal fusion. In this case, airtightness at the bonding interface between the second gasket 173 and the rivet terminal 172 and at the bonding interface between the second gasket 173 and the battery can 171 may be enhanced. On the other hand, in the case where the gasket exposed portion 173a of the second gasket 173 extends to the upper surface of the terminal exposed portion 172a, the rivet terminal 172 is inserted into the second gasket 173 by insert injection. can be integrally combined with

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

The second current collecting plate 176 is coupled to the lower portion 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 current collector.

Preferably, the second current collecting plate 176 is electrically connected to the battery can 171 . To this end, at least a portion of an edge of the second current collecting plate 176 may be fixedly interposed between the inner surface of the battery can 171 and the first gasket 178b. In one example, at least a portion of the edge portion of the second current collecting plate 176 is supported on the bottom surface of the beading portion 180 formed at the bottom of the battery can 171 by laser welding or resistance welding to the beading portion ( 180) can be fixed. In a modified example, at least a portion of an edge portion of the second current collecting plate 176 may be directly welded to the inner wall surface of the battery can 171 .

Preferably, the second current collecting plate 176 and the bent surface of the uncoated region 146b may be joined by welding, for example, laser welding, resistance welding, ultrasonic welding, spot welding, or the like.

The sealing body 178 sealing the lower open end of the battery can 171 includes a cap plate 178a and a first gasket 178b. The first gasket 178b electrically separates the cap plate 178a from the battery can 171 . The crimping part 181 fixes the edge of the cap plate 178a and the first gasket 178b together. The cap plate 178a is provided with a vent part 179 . The configuration of the vent unit 179 is substantially the same as that of the above-described embodiment.

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 an electrical polarity. The sealing body 178 seals the open end of the lower portion of the battery can 171 and functions to discharge gas when the internal pressure of the battery cell 170 increases by more than a threshold value. The cap plate 178a may include a vent portion 179 in an edge region of the flat portion. The configuration of the vent part 179 is substantially the same as that of the above-described embodiment.

Preferably, the rivet terminal 172 electrically connected to the uncoated portion 146a of the first electrode current collector is used as the first electrode terminal. In addition, among the upper surfaces of the battery can 171 electrically connected to the uncoated region 146b of the second electrode current collector through the second current collecting plate 176 , a portion 175 excluding the rivet terminal 172 is the first electrode It is used as a second electrode terminal having a different polarity from the terminal. As such, when the two electrode terminals are located on the upper part of the cylindrical battery cell 170 , it is possible to arrange an electrical connection component such as a bus bar on only one side of the cylindrical battery cell 170 . This may result in a simplification of the battery pack structure and an improvement in energy density. In addition, since the portion 175 used as the second electrode terminal has an approximately flat shape, a sufficient bonding area may be secured for bonding electrical connection components such as bus bars. Accordingly, the cylindrical battery cell 170 may lower the resistance at the joint portion of the electrical connection component to a desirable level.

In the present invention, as shown in FIG. 5 , the uncoated portion constituting the winding turn near the core has a low height. Accordingly, even when the uncoated regions 146a and 146b of the bending target region D are bent toward the core center C of the electrode assembly, the cavity 112 of the core of the electrode assembly 110 may be opened upward without being blocked. have.

If the cavity 112 is not blocked in FIGS. 18 and 19 , there is no difficulty in the electrolyte injection process, and the electrolyte injection efficiency is improved. In addition, 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 electrode 172 can be easily performed. .

A method of manufacturing an electrode assembly according to an embodiment of the present invention will be described. However, 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 described above is replaced with the above description.

First, a first electrode current collector and a second electrode current collector having a sheet shape and having an uncoated region on one side in the longitudinal direction are prepared.

Next, the first electrode current collector, the second electrode current collector, and the separator are laminated at least once so that a separator is interposed between the first electrode current collector and the second electrode current collector, and the uncoated portion of the first electrode current collector and the second An electrode current collector-separator laminate is formed so that the uncoated portions of the electrode current collector are oppositely exposed along the longitudinal direction of the separator.

Next, a jelly roll type electrode assembly is prepared by winding the electrode collector-separator stack in one direction so that the uncoated portion of the first electrode collector and the uncoated portion of the second electrode collector are exposed in opposite directions along the winding axis direction. to form

Next, in the uncoated region of at least one of the uncoated region of the first electrode current collector and the uncoated region of the second electrode current collector, a residual region R remaining in a protruding shape along the winding axis direction is formed in a preset direction. The cutting line 100 is formed along the length direction of the electrode assembly to be divided into the bent target area D to be bent. Here, the cutting line 100 may be formed by a cutter that vibrates ultrasonically in the direction of the winding axis of the electrode assembly. Also, the predetermined uncoated region may be bent along the cutting line 100 .

Next, the method includes bending at least a portion of the uncoated area included in the bending target area D to overlap with a plurality of layers along a bending direction of a predetermined uncoated area.

Next, when the uncoated region is bent, a current collecting plate having a shape corresponding to the shape of the bending target region D may be coupled to the uncoated region of the bending target region D. Here, the current collecting plate may be welded to the uncoated area bent so as to overlap the plurality of layers of the bending target area D by welding.

On the other hand, the details regarding the cutting line 100 and the shape of the bending target area D are replaced with the contents described in the electrode assembly or the cylindrical battery cell according to the embodiment of the present invention.

The cylindrical battery cell according to the above-described embodiments (variations) may be used to manufacture a battery pack.

20 is a diagram schematically illustrating a configuration of a battery pack according to an embodiment of the present invention.

Referring to FIG. 20 , a battery pack 800 according to an embodiment of the present invention includes an assembly to which cylindrical battery cells 810 are electrically connected and a pack housing 820 accommodating the assembly. The cylindrical battery cell 810 may be any one of the battery cells according to the above-described embodiments (modified examples). In the drawings, parts such as a bus bar, a cooling unit, and an external terminal for electrical connection of the cylindrical battery cells 810 are omitted for convenience of illustration.

The battery pack 800 may be mounted in the vehicle 900 . The vehicle 900 may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The vehicle 900 includes a four-wheeled vehicle or a two-wheeled vehicle.

FIG. 21 is a view for explaining a vehicle including the battery pack of FIG. 20 .

Referring to FIG. 21 , a vehicle 900 according to an embodiment of the present invention includes a battery pack 800 according to an embodiment of the present invention. The vehicle 900 operates by receiving power from the battery pack 800 according to an embodiment of the present invention.

According to one aspect of the present invention, the bending target region of the uncoated region having a shape protruding along the winding axis direction of the electrode assembly is formed in a pattern extending along the bending direction, and the uncoated region of the bending target region is bent by bending the bent surface of the uncoated region. flatness can be improved, and the phenomenon that the uncoated area is irregularly bent under the bent surface can be alleviated.

As described above, although the present invention has been described with reference to limited embodiments and drawings, the present invention is not limited thereto, and the technical spirit of the present invention and the following by those of ordinary skill in the art to which the present invention pertains. It goes without saying that various modifications and variations are possible within the scope of equivalents of the claims to be described.

Claims (38)

In the jelly roll type electrode assembly in which the first electrode current collector and the second electrode current collector having a sheet shape and a separator interposed therebetween are wound in one direction,
At least one of the first electrode current collector and the second electrode current collector includes an uncoated region exposed to the outside of the separator along a longitudinal direction of the electrode assembly at a long side end thereof,
A cutting line is formed in the uncoated region of at least one of the uncoated region of the first electrode current collector and the uncoated region of the second electrode current collector along the length direction of the electrode assembly,
The uncoated region in which the cutting line is formed is divided into a residual region remaining in a protruding shape along a winding axis direction with respect to the cutting line and a bending target region bent in a preset direction,
The electrode assembly, characterized in that at least a portion of the uncoated region included in the bending target region is bent so as to overlap with a plurality of layers along a bending direction of the predetermined uncoated region. According to claim 1,
A current collecting plate having a shape corresponding to the shape of the bending target area is coupled to the uncoated part of the bending target area. 3. The method of claim 2,
The current collecting plate is an electrode assembly, characterized in that coupled to the uncoated portion of the bending target region by welding. According to claim 1,
The cutting line is an electrode assembly, characterized in that formed by at least one cut. 5. The method of claim 4,
The cutting line is an electrode assembly, characterized in that formed by a cutter that vibrates ultrasonically in the direction of the winding axis of the electrode assembly. 3. The method of claim 2,
After the current collecting plate is coupled to the uncoated portion of the bending target region, the total height of the current collecting plate and the uncoated portion corresponds to a height of the remaining uncoated portion in a protruding shape along a winding axis direction of the remaining region. electrode assembly. 7. The method of claim 6,
The electrode assembly according to claim 1 , wherein the sum of the height of the current collecting plate and the uncoated portion under the bending target region is the same as the height of the uncoated portion protruding from the remaining region. According to claim 1,
An electrode assembly, characterized in that a gap is formed between any one uncoated area of the uncoated area of the remaining area and the other uncoated area. 9. The method of claim 8,
The electrode assembly of claim 1, wherein the electrolyte is configured to move through the gap. According to claim 1,
The electrode assembly, characterized in that the predetermined uncoated portion is bent along the cutting line. According to claim 1,
The electrode assembly, characterized in that the predetermined bending direction of the uncoated region is a radial direction of the electrode assembly. The method of claim 1,
The electrode assembly, characterized in that the bending direction of the predetermined uncoated region is a core direction of the electrode assembly. According to claim 1,
The shape of the bent target region is an electrode assembly, characterized in that it extends along a radial direction when viewed in the direction of the winding axis of the electrode assembly. According to claim 1,
The shape of the bending target region is an electrode assembly, characterized in that when viewed in the direction of the winding axis of the electrode assembly, the electrode assembly, characterized in that the radial shape outward from the center of the core of the electrode assembly. 15. The method of claim 14,
The shape of the bending target region is an electrode assembly, characterized in that when viewed in the direction of the winding axis of the electrode assembly, the electrode assembly, characterized in that the radial shape extending outward in two or more directions from the center of the core of the electrode assembly. According to claim 1,
The shape of the bending target region is a cross shape extending outward from the center of the core of the electrode assembly when viewed in the direction of the winding axis of the electrode assembly. According to claim 1,
The shape of the bending target region is a radial shape extending outwardly from the center of the core of the electrode assembly when viewed in the direction of the winding axis of the electrode assembly,
The cutting line is an electrode assembly, characterized in that curved toward the core of the electrode assembly in the form of an arc. According to claim 1,
At least a portion of the uncoated region included in the bending target region is bent toward the core of the electrode assembly. According to claim 1,
At least a portion of the uncoated region included in the bending target region is bent to overlap with at least three layers along a radial direction of the electrode assembly. According to claim 1,
At least a portion of the uncoated region included in the bending target region is bent to overlap with at least four layers along a radial direction of the electrode assembly. According to claim 1,
At least a portion of the uncoated region included in the bending target region is bent so as to overlap with at least five or more layers in a radial direction of the electrode assembly. According to claim 1,
An electrode plate is formed including the first electrode current collector and an active material layer formed on at least one surface of the first electrode current collector,
The electrode plate includes an insulating coating layer formed at a boundary between the active material layer and the uncoated region of the first electrode current collector,
The insulating coating layer is exposed to the outside of the separator,
The electrode assembly, characterized in that the lower end of the cutting line around the bending target region is spaced apart from the end of the insulating coating layer. According to claim 1,
An electrode plate is formed including the second electrode current collector and an active material layer formed on at least one surface of the second electrode current collector,
The electrode plate includes an insulating coating layer formed at the boundary between the active material layer and the uncoated region of the second electrode current collector,
The insulating coating layer is exposed to the outside of the separator,
The electrode assembly, characterized in that the lower end of the cutting line around the bending target region is spaced apart from the end of the insulating coating layer. (a) preparing a first electrode current collector and a second electrode current collector having a sheet shape and having an uncoated region on one side in the longitudinal direction;
(b) stacking the first electrode current collector, the second electrode current collector, and the separator at least once so that a separator is interposed between the first electrode current collector and the second electrode current collector, wherein the first electrode collector forming the electrode current collector-separator stack so that the entire uncoated region and the uncoated region of the second electrode current collector are oppositely exposed along a longitudinal direction of the separator;
(c) a jelly roll type so that the electrode collector-separator laminate is wound in one direction so that the uncoated portion of the first electrode collector and the uncoated portion of the second electrode collector are exposed in opposite directions along the winding axis direction forming an electrode assembly of
(d) in at least one uncoated region of the uncoated region of the first electrode current collector and the uncoated region of the second electrode current collector, a residual region remaining in a protruding shape along the winding axis direction; forming a cutting line along a length direction of the electrode assembly to be divided into a bent target area to be bent; and
(e) bending at least a portion of the uncoated region included in the bending target region to overlap in a plurality of layers along a bending direction of a predetermined uncoated region. 25. The method of claim 24,
and coupling 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. 26. The method of claim 25,
and bonding the current collecting plate to the uncoated region bent to overlap the plurality of layers of the bending target region by welding. 25. The method of claim 24,
and the cutting line is formed by a cutter that vibrates ultrasonically in a direction of a winding axis of the electrode assembly. 25. The method of claim 24,
and bending the predetermined uncoated region along the cutting line. 25. The method of claim 24,
A plurality of cutting lines in the bending target area,
When viewed in the direction of the winding axis of the electrode assembly, the plurality of cutting lines form two pairs and extend along the radial direction of the electrode assembly. 25. The method of claim 24,
A plurality of cutting lines in the bending target area,
When viewed in the direction of the winding axis of the electrode assembly, the plurality of cutting lines form two pairs and radially extend outward from the center of the electrode assembly. 25. The method of claim 24,
A plurality of cutting lines in the bending target area,
When viewed in the direction of the winding axis of the electrode assembly, each of the plurality of cutting lines is an electrode assembly manufacturing method, characterized in that it has an arc shape curved toward the center of the electrode assembly. The method of claim 24, wherein in step (e),
The electrode assembly manufacturing method according to claim 1, wherein at least a portion of the uncoated region included in the bending target region is bent toward a core direction of the electrode assembly. The method of claim 24, wherein in step (e),
The method of claim 1, wherein at least a portion of the uncoated region included in the bending target region is bent to overlap with at least three or more layers in a radial direction of the electrode assembly. The method of claim 24, wherein in step (e),
The method of claim 1, wherein at least a portion of the uncoated region included in the bending target region is bent to overlap with at least four layers along a radial direction of the electrode assembly. The method of claim 24, wherein in step (e),
The method of claim 1, wherein at least a portion of the uncoated region included in the bending target region is bent to overlap with at least five or more layers along a radial direction of the electrode assembly. A jelly roll type electrode assembly in which a first electrode current collector and a second electrode current collector having a sheet shape and a separator interposed therebetween are wound in one direction, wherein the first electrode current collector and the second electrode current collector are wound in one direction. at least one includes an uncoated region exposed to the outside of the separator in a longitudinal direction of the electrode assembly at a long side end, and at least one of the uncoated region of the first electrode current collector and the uncoated region of the second electrode current collector A cutting line is formed in the uncoated region along the length direction of the electrode assembly, and the uncoated region on which the cutting line is formed includes a residual region that protrudes along the winding axis with respect to the cutting line, and a preset direction. an electrode assembly divided into a bending target area bent by a , and wherein at least a portion of the uncoated area included in the bending target area is bent to overlap a plurality of layers along a bending direction of a predetermined uncoated area;
a cylindrical battery can in which the electrode assembly is accommodated and electrically connected to the second electrode current collector;
a sealing body sealing the open end of the battery can;
an external terminal electrically connected to the first electrode current collector and having a surface exposed to the outside; and
and a current collecting plate welded to the bent surface of the uncoated region and electrically connected to any one of the battery can and the external terminal. A battery pack comprising the cylindrical battery cell according to claim 36 . A motor vehicle comprising the battery pack according to claim 37 .

Images