Electrode sheet heating device, electrode sheet heating method, and jelly roll-type electrode assembly

Abstract

The present invention relates to an electrode sheet heating device, and includes a heating unit configured to heat a predetermined area of ​​an underside of an electrode sheet fed in a predetermined feed direction, the electrode sheet being wound up to be manufactured into a wound electrode in a jelly roll electrode assembly, and the predetermined area may include an area of ​​the electrode sheet corresponding to an end area located at the outermost end of the wound electrode in the jelly roll electrode assembly, or an area of ​​the electrode sheet corresponding to a step-occurring area of ​​one of the wound electrodes when a step occurs at the outer end of the wound electrode due to a difference in length of the wound electrodes in the jelly roll electrode assembly.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0144042, filed November 1, 2022, and Korean Patent Application No. 10-2023-0148852, filed November 1, 2023, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to an electrode sheet heating device, an electrode sheet heating method, and a jelly-roll type electrode assembly. [Background technology]

[0003] In general, secondary batteries are batteries that can be charged and discharged, unlike primary batteries that cannot be recharged, and are widely used in electronic devices such as mobile phones, laptops, and camcorders, as well as electric vehicles, etc. In particular, lithium secondary batteries have a larger capacity and higher energy density than nickel-cadmium batteries or nickel-metal hydride batteries, and therefore their use is rapidly increasing.

[0004] Secondary batteries are classified according to the shape of the battery case into cylindrical batteries in which the electrode assembly is housed in a cylindrical metal can, prismatic batteries in which the electrode assembly is housed in a prismatic metal can, and pouch batteries in which the electrode assembly is housed in a pouch-shaped case made of a laminate sheet.

[0005] Fig. 1 is a perspective view showing a typical cylindrical battery, and Fig. 2 is an exploded perspective view of the cylindrical battery of Fig. 1. As shown in Figs. 1 and 2, the cylindrical battery can include a jelly-roll type electrode assembly 20 and a cylindrical case 10 that houses the jelly-roll type electrode assembly 20.

[0006] The jelly-roll type electrode assembly 20 may be inserted into the cylindrical case 10 through an opening in the cylindrical case 10. After the insertion, an electrolyte may be injected into the cylindrical case 10 through the opening. After the electrolyte is injected, the opening of the cylindrical case 10 may be covered with a cap assembly 30.

[0007] The cap assembly 30 may include an upper cap 31 and a safety vent 32. The upper cap 31 may be closely attached to the safety vent 32 and electrically connected to the safety vent 32. One of the electrodes of the electrode assembly 20 may be electrically connected to the upper cap 31 through the safety vent 32.

[0008] The cylindrical battery may further include a gasket 40 for sealing between the cylindrical case 10 and the cap assembly 30. The upper end of the cylindrical case 10 may be bent toward the gasket 40 after the gasket 40 is installed.

[0009] Meanwhile, the jelly roll electrode assembly 20 may have a structure in which a first wound electrode and a second wound electrode are wound with a separator interposed therebetween. The wound electrodes may have different lengths. Due to this difference in length, a step may be formed between the wound electrodes at the outer ends of the jelly roll electrode assembly 20. A secondary battery may undergo a charge / discharge process for activation, and during this process, the volume of the electrode assembly 20 may expand. This expansion may apply strong stress to the portion of the wound electrode that forms the step. This may result in breakage of the current collector in the wound electrode, which may increase the resistance of the battery and increase the risk of fire due to heat generation. Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide an electrode sheet heating device, an electrode sheet heating method, and a jelly-roll-type electrode assembly in which, even if any region of a wound electrode in a jelly-roll-type electrode assembly forms a step in the jelly-roll-type electrode assembly, breakage of the current collector in that region does not occur or breakage is delayed. [Means for solving the problem]

[0011] In one example, the electrode sheet heating device includes a heating unit configured to heat the underside of a predetermined region of an electrode sheet fed in a predetermined feed direction, the electrode sheet being wound up to be manufactured into a wound electrode in a jelly roll electrode assembly, and the predetermined region may include a region of the electrode sheet corresponding to an end region located at the outermost end of the wound electrode in the jelly roll electrode assembly, or a region of the electrode sheet corresponding to a step-occurring region of one of the wound electrodes when a step occurs at the outer end of the wound electrode due to a difference in length of the wound electrodes in the jelly roll electrode assembly.

[0012] In another example, the electrode sheet includes a current collector sheet and an active material layer applied to the current collector sheet, and the heating unit may heat the predetermined region to a temperature that increases the elongation of the current collector sheet.

[0013] In yet another example, the heating unit can heat the predetermined area at 130°C to 150°C.

[0014] In yet another example, the electrode sheet includes a current collector sheet and an active material layer applied to the current collector sheet, and the heating unit can heat the specified region so that the elongation of the current collector sheet provided in the specified region becomes 13% to 20% when the elongation of the current collector sheet provided in an adjacent region of the electrode sheet adjacent to the specified region is 10% or less.

[0015] In yet another example, the heating section may include a support plate extending in a direction transverse to the feed direction and configured to support the lower surface of the electrode sheet, and a heater configured to heat the support plate.

[0016] In yet another example, the electrode sheet heating device may further include an attachment unit configured to attach a tape to an upper surface of the predetermined area supported by the support plate.

[0017] In yet another example, the attachment portion may include a pressure plate disposed opposite the support plate and configured to move toward the upper surface of the electrode sheet, and a drive rod configured to move the pressure plate in a direction toward the upper surface of the electrode sheet and in the opposite direction.

[0018] In yet another example, the pressure plate may be configured to attach the tape, which is to be attached to the upper surface of the electrode sheet, to the lower surface of the pressure plate by suction.

[0019] In yet another example, a jelly roll electrode assembly has a structure in which a first wound electrode and a second wound electrode are wound with a separator interposed therebetween, and the elongation rate of a first region including an end region located at the outermost end of the first wound electrode may be higher than the elongation rate of a second region of the first wound electrode located adjacent to the first region along the opposite direction to the winding direction, when the winding direction is the direction in which the first wound electrode is wound from the center of the jelly roll electrode assembly.

[0020] In yet another example, the first wound electrode includes a first current collector sheet and a first active material layer applied to the first current collector sheet, and the second wound electrode includes a second current collector sheet and a second active material layer applied to the second current collector sheet, and the elongation of the first and second wound electrodes can be obtained based on the elongation of the first and second current collector sheets.

[0021] In still another example, the elongation of the current collector sheet provided in the first region may be 13% to 20%, and the elongation of the current collector sheet provided in the second region may be 10% or less.

[0022] In yet another example, the outermost layer of the first wound electrode may be located radially outward of the jelly roll electrode assembly relative to the outermost layer of the second wound electrode, and the outermost end of the first wound electrode may protrude outward from the outermost end of the second wound electrode along the winding direction.

[0023] In yet another example, the first region can include a region of the first winding electrode that protrudes outward from the outermost end of the second winding electrode.

[0024] In yet another example, the jelly roll electrode assembly may further include a tape attached to a region of the first windable electrode that protrudes outward from the outermost end of the second windable electrode.

[0025] In yet another example, the first wound electrode can be a negative wound electrode.

[0026] In yet another example, there is provided a jelly roll electrode assembly having a structure in which a first wound electrode and a second wound electrode are wound with a separator interposed therebetween, wherein the outermost layer of the first wound electrode is located radially outward of the jelly roll electrode assembly relative to the outermost layer of the second wound electrode, and the outermost end of the first wound electrode protrudes outward from the outermost end of the second wound electrode along the winding direction, where the direction in which the first wound electrode is wound from the center of the jelly roll electrode assembly is defined as the winding direction, and the first wound electrode includes a first region including a point on the first wound electrode corresponding to the outermost end of the second wound electrode, and a second region extending from the first region in the winding direction or in a direction opposite to the winding direction, and the elongation rate of the first region may be higher than that of the second region.

[0027] In yet another example, a method for heating an electrode sheet includes: (a) feeding an electrode sheet in a predetermined feed direction; and (b) heating one side of a predetermined region of the electrode sheet, wherein in step (b), the electrode sheet may be heated to a temperature that increases the elongation of a current collector sheet of the electrode sheet.

[0028] In yet another example, the predetermined region may include a region of the electrode sheet corresponding to an end region located at the outermost end of a wound-up electrode in a jelly roll-type electrode assembly, or a region of the electrode sheet corresponding to a step-occurring region of one of the wound-up electrodes when a step occurs at the outer end of the wound-up electrode due to a difference in length of the wound-up electrodes in the jelly roll-type electrode assembly.

[0029] In yet another example, the method for heating an electrode sheet may further include, simultaneously with step (b), attaching tape to the other surface of the predetermined region of the electrode sheet.

[0030] In yet another example, step (b) may be a step of determining the heating temperature based on the material properties of the current collector sheet. [Effects of the Invention]

[0031] According to the present invention, by preheating a predetermined region of an electrode sheet during the manufacture of an electrode assembly and increasing the elongation of the current collector sheet in that region, even if a predetermined region of a wound electrode forms a step in a jelly-roll type electrode assembly after the electrode assembly is manufactured, breakage of the current collector sheet can be prevented or delayed.

[0032] Furthermore, according to the present invention, since the first region of the wound electrode in the jelly roll electrode assembly has a higher elongation rate than the adjacent second region, even if a predetermined region of the wound electrode forms a step in the jelly roll electrode assembly, breakage of the current collector sheet can be prevented or delayed. [Brief explanation of the drawings]

[0033] [Figure 1] FIG. 1 is a perspective view showing a typical cylindrical battery. [Figure 2] FIG. 2 is an exploded perspective view of the cylindrical battery of FIG. 1. [Figure 3] 1 is a perspective view showing a manufacturing apparatus for a jelly-roll type electrode assembly to which an electrode sheet heating device according to a first embodiment of the present invention is applied. FIG. [Figure 4] 1 is a graph showing the elongation of copper with respect to temperature. [Figure 5] FIG. 10 is a cross-sectional view showing a jelly-roll type electrode assembly according to a second embodiment of the present invention. [Figure 6] FIG. 6 is a cross-sectional view showing a modified example of the jelly-roll type electrode assembly of FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0034] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily understand the preferred embodiments of the present invention. However, the present invention may be realized in various different forms and is not limited to the following embodiments.

[0035] In order to clearly explain the present invention, detailed descriptions of parts that are not relevant to the explanation or related known technologies that may obscure the gist of the present invention will be omitted, and in this specification, when adding reference symbols to components in each drawing, the same or similar reference symbols will be used throughout the specification to refer to the same or similar components.

[0036] Furthermore, the terms and words used in this specification and claims should not be interpreted in a limited way to their ordinary and dictionary meanings, but should be interpreted in a way that is consistent with the technical idea of ​​the present invention, in accordance with the principle that an inventor can appropriately define the concept of a term in order to best explain his or her invention.

[0037] Embodiment 1 FIG. 3 is a perspective view showing a manufacturing apparatus for a jelly-roll type electrode assembly to which the electrode sheet heating device according to the first embodiment of the present invention is applied.

[0038] As shown in FIG. 3, the jelly roll electrode assembly A may be manufactured by continuously winding a first separator sheet S1, a first electrode sheet 110, a second separator sheet S2, and a second electrode sheet 120 around a predetermined winding center C. Through this process, the jelly roll electrode assembly A may have a structure in which a first wound electrode 210 (see FIG. 5) and a second wound electrode 220 (see FIG. 5) are wound with separators 271 and 272 (see FIG. 5) interposed therebetween. The first electrode sheet 110 may be cut after winding to form a part of the jelly roll electrode assembly 200 (see FIG. 5), thereby manufacturing the first wound electrode 210 in the jelly roll electrode assembly 200. The same applies to the second electrode sheet 120.

[0039] The first electrode sheet 110 may be a negative electrode sheet. The first electrode sheet 110 may include a first current collector sheet 111 and a first active material layer 112 applied to the first current collector sheet 111. The first current collector sheet 111 may include, but is not limited to, copper foil.

[0040] The second electrode sheet 120 may be a positive electrode sheet. The second electrode sheet 120 may include a second current collector sheet 121 and a second active material layer 122 applied to the second current collector sheet 121. The second current collector sheet 121 may include, but is not limited to, aluminum foil.

[0041] Electrode sheet heating device 100 The heating device 100 of this embodiment may include a heating unit 130 that is provided to heat the lower surface of a predetermined region 110a of the electrode sheet 110 that is fed in a predetermined feed direction F.

[0042] FIG. 3 illustrates a heating device 100 that heats the first electrode sheet 110 of the first and second electrode sheets 110, 120. The heating device 100 may be configured to heat the second electrode sheet 120. The following describes a case where the heating device 100 heats the first electrode sheet 110. FIG. 3 also illustrates a heating device 100 that heats the lower surface of the first electrode sheet 110. The heating device 100 may be configured to heat the upper surface of the first electrode sheet 110. For reference, the feed direction F may be a direction in which the electrode sheet 110 is transported toward a winding center C for winding.

[0043] The predetermined region 110a of the first electrode sheet 110 may include any region of the first electrode sheet 110 that corresponds to the terminal region 210a located at the outermost end 210c of the first wound electrode 210 (see FIG. 5) in the jelly roll electrode assembly 200 (see FIG. 5). For example, the predetermined region 110a of the first electrode sheet 110 may be any region of the first electrode sheet 110 that will form the terminal region 210a of the first wound electrode 210 in the jelly roll electrode assembly 200 when the first electrode sheet 110 is wound to form the jelly roll electrode assembly 200.

[0044] As shown in FIG. 5 , the jelly roll electrode assembly 200 may have an outermost layer of the first winding electrode 210 positioned outward in the radial direction D1 of the jelly roll electrode assembly A relative to the outermost layer of the second winding electrode 220. The outermost end 210c of the first winding electrode 210 may protrude outward from the outermost end 220c of the second winding electrode 220 along the winding direction D2. The end region 210a of the first winding electrode 210 may include a portion positioned further outward in the winding direction D2 than the outermost end 220c of the second winding electrode 220, or may include this portion and a portion positioned further inward in the opposite winding direction D3 than the outermost end 220c of the second winding electrode 220. The overall length of the first winding electrode 210 may be longer than the overall length of the second winding electrode 220. For reference, the winding direction D2 may be a direction in which the first winding electrode 210 is wound from the center of the jelly roll electrode assembly 200. Due to the above-described structure, the jelly roll electrode assembly 200 may have a step R formed at the end in the winding direction D2.

[0045] Meanwhile, the volume of the electrode assembly 200 may expand during the charge / discharge process for activation. However, this volume expansion may cause strong stress to be applied to a portion of the first winding electrode 210 that forms the step R. This may result in breakage of the first current collector sheet 111 (see FIG. 3) of the first winding electrode 210. Breakage of the first current collector sheet 111 may increase the battery resistance and increase the risk of fire due to heat generation.

[0046] The heating device 100 of this embodiment preheats a predetermined region 110a (see FIG. 3) of the electrode sheet 110 corresponding to the end region 210a of the first wound electrode 210, which may form the aforementioned step R of the jelly roll electrode assembly 200, during the manufacture of the electrode assembly A. As a result, the elongation of the first current collector sheet 111 of the first wound electrode 210 can be increased in the end region 210a (see FIG. 5) of the first wound electrode 210, thereby preventing or delaying breakage of the first current collector sheet 111. Copper and other materials constituting the first current collector sheet 111 have the property that their elongation increases when heated at a specific temperature. This is because, as the elongation increases, the energy required for firing breakage also increases, making the sheet less likely to break.

[0047] As described above, the heating device 100 of this embodiment preheats a predetermined region 110a of the electrode sheet 110, including a region of the electrode sheet 110 that corresponds to the terminal region 210a of the wound electrode 210, during the manufacture of the electrode assembly A, thereby increasing the elongation rate of the collector sheet 111 in that region. This makes it possible to prevent or delay breakage of the collector sheet 111 even if the terminal region 210a of the wound electrode 210 forms a step R in the electrode assembly 200 after the electrode assembly 200 is manufactured.

[0048] heating section 130 3, the heating device 100 of this embodiment may include a heating unit 130 for heating a predetermined region 110a of the electrode sheet 110. The heating unit 130 will be described in detail below.

[0049] The heating unit 130 may include a support plate 131 extending in a direction transverse to the feed direction F (e.g., a direction perpendicular to the feed direction) and configured to support the lower surface of the electrode sheet 110. The support plate 131 may be configured to move vertically to come into close contact with the lower surface of the electrode sheet 110. Alternatively, the support plate 131 may be fixed in a position to come into close contact with the lower surface of the electrode sheet 110. The heating unit 130 may include a heater 132 configured to heat the support plate 131. The heater 132 may be a coil heater built into the support plate 131. The heating unit 130 controls the heater 132 to heat the support plate 131, thereby heating the electrode sheet 110 supported by the support plate 131 to a predetermined temperature.

[0050] The heating unit 130 may heat the predetermined region 110a of the electrode sheet 110 at a temperature that increases the elongation of the current collector sheet 111. For example, the heating unit 130 may heat the predetermined region 110a of the electrode sheet 110 at a temperature between 130°C and 150°C. This temperature range is effective when the current collector sheet 111 is made of copper foil, as shown in FIG. 4. FIG. 4 is a graph showing the elongation of copper as a function of temperature. The elongation of copper material may increase relatively significantly when heated at a temperature between 130°C and 150°C. The temperature range at which the heating unit 130 heats the predetermined region 110a may vary depending on the characteristics of the material constituting the current collector sheet 111.

[0051] When the elongation rate of the collector sheet 111 provided in the adjacent region 110b of the electrode sheet 110 adjacent to the predetermined region 110a of the electrode sheet 110 is 10% or less, the heating unit 130 can heat the predetermined region 110a so that the elongation rate of the collector sheet provided in the predetermined region 110a becomes 13% to 20%.

[0052] For reference, the elongation can be measured using a tensile tester. For example, after obtaining a heat-treated current collector sheet to a predetermined length (e.g., 10 to 15 mm), the current collector sheet is uniaxially stretched (e.g., at a speed of 50 mm / min) and the stretch length until it breaks is measured, thereby measuring the elongation of the current collector sheet (the rate at which the current collector sheet stretches).

[0053] Attachment part 140 3, the heating device 100 of this embodiment may include an attachment portion 140 that is provided to attach tape 150 to the upper surface of a predetermined region 110a of the electrode sheet 110 supported by the support plate 131. As described above, the current collector sheet is prone to breakage at the step R (see FIG. 5) of the electrode assembly 200, but by attaching tape 150 to this region in advance during the manufacture of the electrode assembly A, it is possible to prevent or delay the occurrence of such breakage.

[0054] The attachment unit 140 may include a pressure plate 141 disposed opposite the support plate 131 and configured to move toward the upper surface of the electrode sheet 110. The attachment unit 140 may include a drive rod 142 configured to move the pressure plate 141 toward the upper surface of the electrode sheet 110 and in the opposite direction. By moving the pressure plate 141 by the drive rod 142 to the upper surface of the electrode sheet 110 supported by the support plate 131, the tape 150 can be attached to the upper surface of the electrode sheet 110. The pressure plate 141 can move until it presses the support plate 131 with the tape 150 interposed therebetween.

[0055] The pressure plate 141 can selectively attach the tape 150 to its lower surface, and for this purpose, the pressure plate 141 can have a structure for suctioning the tape 150. For example, the tape 150 can be attached to the lower surface of the pressure plate 141 by suction, and the tape 150 can be removed from the lower surface of the pressure plate 141 by releasing the suction.

[0056] Meanwhile, a tape attachment device that attaches the tape 150 to the upper surface of the electrode sheet 110 may include a pressure plate 141 for applying pressure to attach the tape 150, and may include a support plate 131 for supporting the lower surface of the electrode sheet 110 while applying pressure with the pressure plate 141. If the support plate 131 of such an attachment device is provided with a heat generating function, attachment of the tape 150 and heating of the electrode sheet 110 can be achieved simultaneously.

[0057] Electrode sheet heating method The electrode sheet 110 can be heated through the following series of steps.

[0058] First, the electrode sheet 110 may be fed in a predetermined feeding direction. While the feeding is continuing or while the feeding is interrupted, one surface (e.g., the lower surface) of a predetermined region 110a of the electrode sheet 110 may be heated. The electrode sheet 110 may be heated to a temperature that increases the elongation of the current collector sheet 111 of the electrode sheet 110. The heating temperature may be determined based on the material properties of the current collector sheet 111.

[0059] The predetermined region 110a of the electrode sheet 110 may include a region of the electrode sheet 110 corresponding to an end region located at the outermost end of a wound-up electrode in a jelly roll electrode assembly. Alternatively, the predetermined region 110a of the electrode sheet 110 may include a region of the electrode sheet 110 corresponding to a step-occurring region of one of the wound-up electrodes when a step occurs at the outer end of the wound-up electrode due to a difference in length between the wound-up electrodes in the jelly roll electrode assembly. For example, the step-occurring region may be specified to include a point P1 (see FIG. 6) of the first wound-up electrode 210 corresponding to the outermost end 220c of the second wound-up electrode 220 in the electrode assembly.

[0060] At the same time as heating the predetermined region 110a of the electrode sheet 110, tape may be attached to the other surface (for example, the upper surface) of the electrode sheet in the predetermined region 110a.

[0061] Embodiment 2 5 is a cross-sectional view showing a jelly-roll type electrode assembly according to embodiment 2 of the present invention. The jelly-roll type electrode assembly 200 of embodiment 2 may be an electrode assembly 200 employing an electrode sheet that has been heat-treated by the electrode sheet heating device 100 of embodiment 1. However, the electrode sheet used in the jelly-roll type electrode assembly 200 of embodiment 2 is not limited to the electrode sheet that has been heat-treated by the electrode sheet heating device 100 of embodiment 1.

[0062] The jelly roll electrode assembly 200 of this embodiment may have a structure in which a first winding-type electrode 210 and a second winding-type electrode 220 are wound with separators 271 and 272 interposed therebetween. The first winding-type electrode 210 may be a negative winding-type electrode, and the second winding-type electrode 220 may be a positive winding-type electrode.

[0063] The first winding electrode 210 may include a first region 261 including a terminal region 210a located at the outermost end 210c of the first winding electrode 210. The first region 261 may be identical to the terminal region 210a, or may include the terminal region 210a and be wider than the terminal region 210a. The first winding electrode 210 may include a second region 262 of the first winding electrode 210 located adjacent to the first region 261 along the opposite direction D3 to the winding direction.

[0064] The first region 261 may be a region of the first winding electrode 210 having a length of 3 cm to 6 cm along the winding direction D2. The length of the first region 261 may be a length that allows attachment of tape. The first region 261 may be a region having a length that corresponds to 5% to 10% of the entire length of the first winding electrode 210 along the winding direction D2.

[0065] In this embodiment, the elongation rate of the first region 261 of the first winding electrode 210 may be higher than the elongation rate of the second region 262. The elongation rates of the first and second winding electrodes 210, 220 may be obtained based on the elongation rates of the first and second current collector sheets 111, 121 (see FIG. 3 ) that respectively constitute the first and second winding electrodes 210, 220. For example, the elongation rate of the first current collector sheet 111 may be considered to be the elongation rate of the first winding electrode 210.

[0066] In the jelly roll electrode assembly 200 of this embodiment, the first region 261 of the wound electrode 210, which includes the end region 210a of the wound electrode 210, has a higher elongation rate than the adjacent second region 262. Therefore, even if the end region 210a of the wound electrode 210 forms a step R in the jelly roll electrode assembly 200, breakage of the collector sheet 111 can be prevented or delayed.

[0067] In the first wound electrode 210 in the jelly roll electrode assembly 200 of this embodiment, the elongation of the current collector sheet 111 provided in the first region 261 may be 13% to 20%, and the elongation of the current collector sheet 111 provided in the second region 262 may be 10% or less.

[0068] Meanwhile, the outermost layer of the first winding electrode 210 may be positioned outward in the radial direction D1 of the jelly roll electrode assembly 200 relative to the outermost layer of the second winding electrode 220. The outermost end 210c of the first winding electrode 210 may protrude outward in the winding direction D2 relative to the outermost end 220c of the second winding electrode 220. Due to this structure, a step R may be formed in the jelly roll electrode assembly 200.

[0069] The first region 261 of the first winding electrode 210 may include a region of the first winding electrode 210 (hereinafter, referred to as the protruding region; for example, region 210a in FIG. 5) that protrudes outward from the outermost end 220c of the second winding electrode 220. Since the protruding region 210a of the first winding electrode 210 is the region that forms the above-mentioned step R, the elongation rate of the first region 261, which includes the entire protruding region 210a, may be higher than that of other regions to prevent breakage. For reference, the protruding region may be the same as region 210a in FIG. 5 or may be a part of region 210a. The first region 261 may be specified as the entire protruding region, or as a region including the entire protruding region and a region extending from the protruding region.

[0070] The electrode assembly 200 of this embodiment may further include a tape 250 attached to the protruding region of the first wind-up electrode 210. When the electrode assembly 200 further includes the tape 250 attached to the protruding region, breakage can be more effectively prevented.

[0071] Meanwhile, the first and second regions may be specified as shown in Figure 6. Figure 6 is a cross-sectional view showing a modification of the jelly-roll type electrode assembly of Figure 5. The electrode assembly 200' of Figure 6 differs from the electrode assembly 200 of Figure 5 in the positions of the first and second regions.

[0072] In the electrode assembly 200′ of FIG. 6 , the first region 261′ may be defined to include a point P1 of the first winding electrode 210 corresponding to the outermost end 220c of the second winding electrode 220. The second region 262′ may be a region extending from the first region 261′ in the winding direction D2 or in the opposite direction D3 to the winding direction. In this case, the elongation rate of the first region 261′ may be higher than that of the second region 262′. In the step of the electrode assembly, the portion to which the greatest force is applied to the first winding electrode 210 may be a point P1 of the first winding electrode 210 corresponding to the outermost end 220c of the second winding electrode 220. In this modified example, the first region 261′ may be defined as described above in consideration of this point. The definition of the first and second regions (a predetermined region and an adjacent region) is similarly applicable to the heating device of the first embodiment.

[0073] The above description is merely an illustrative example of the technical concept of the present invention, and various modifications and variations may be made by a person having ordinary skill in the art to which the present invention pertains without departing from the essential characteristics of the present invention.

[0074] Therefore, the embodiments disclosed in the present invention are for illustrative purposes only and are not intended to limit the technical idea of ​​the present invention, and the scope of the technical idea of ​​the present invention is not limited by such embodiments.

[0075] The scope of protection of the present invention should be interpreted by the appended claims, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the present invention.

Claims

1. a heating unit provided to heat a lower surface of a predetermined region of the electrode sheet fed in a predetermined feed direction, The electrode sheet is provided to be wound up to be manufactured into a wound electrode in a jelly roll type electrode assembly, The predetermined region includes a region of the electrode sheet corresponding to an end region located at the outermost end of the wound-up electrode in the jelly roll-type electrode assembly, or a region of the electrode sheet corresponding to a step-occurring region of one of the wound-up electrodes when a step occurs at the outer end of the wound-up electrode due to a difference in length of the wound-up electrodes in the jelly roll-type electrode assembly.

2. the electrode sheet includes a current collector sheet and an active material layer applied to the current collector sheet, The electrode sheet heating device according to claim 1 , wherein the heating unit heats the predetermined region at a temperature that increases the elongation of the current collector sheet.

3. The electrode sheet heating device according to claim 2, wherein the heating section heats the predetermined area at a temperature of 130°C to 150°C.

4. the electrode sheet includes a current collector sheet and an active material layer applied to the current collector sheet, 2. The electrode sheet heating device according to claim 1, wherein when the elongation rate of the collector sheet provided in an adjacent region of the electrode sheet adjacent to the predetermined region is 10% or less, the heating unit heats the predetermined region so that the elongation rate of the collector sheet provided in the predetermined region becomes 13% to 20%.

5. The heating unit is a support plate extending in a direction transverse to the feed direction and configured to support a lower surface of the electrode sheet; The electrode sheet heating device according to claim 1 , further comprising: a heater configured to heat the support plate.

6. The electrode sheet heating device according to claim 5 , further comprising an attachment portion provided to attach a tape to an upper surface of the predetermined region supported by the support plate.

7. The attachment portion is a pressure plate disposed opposite the support plate and configured to move toward the upper surface of the electrode sheet; 7. The electrode sheet heating device according to claim 6, further comprising: a drive rod provided to move the pressure plate in a direction toward the upper surface of the electrode sheet and in a direction opposite thereto.

8. 8. The electrode sheet heating device according to claim 7, wherein the pressure plate is provided so as to adhere the tape to the upper surface of the electrode sheet to the lower surface of the pressure plate by suction.

9. A jelly-roll type electrode assembly having a structure in which a first wound electrode and a second wound electrode are wound with a separator interposed therebetween, A jelly roll electrode assembly, wherein the elongation of a first region including an end region located at the outermost end of the first wound electrode is higher than the elongation of a second region of the first wound electrode located adjacent to the first region along a direction opposite to the winding direction, when the direction in which the first wound electrode is wound from the center of the jelly roll electrode assembly is defined as the winding direction.

10. the first wound electrode includes a first current collector sheet and a first active material layer coated on the first current collector sheet, the second wound electrode includes a second current collector sheet and a second active material layer coated on the second current collector sheet, 10. The jelly roll electrode assembly of claim 9, wherein the elongation of the first and second wound electrodes is obtained based on the elongation of the first and second current collector sheets.

11. the elongation of the current collector sheet provided in the first region is 13% to 20%, The jelly-roll type electrode assembly of claim 10 , wherein the current collector sheet provided in the second region has an elongation percentage of 10% or less.

12. an outermost layer of the first wound electrode is located radially outward of the jelly-roll electrode assembly relative to an outermost layer of the second wound electrode; The jelly roll electrode assembly of claim 10 , wherein an outermost end of the first wound electrode protrudes outward from an outermost end of the second wound electrode in the winding direction.

13. 13. The jelly roll electrode assembly of claim 12, wherein the first region comprises a region of the first wound electrode that protrudes outward from an outermost end of the second wound electrode.

14. 13. The jelly roll electrode assembly of claim 12, further comprising a tape attached to a region of the first wound electrode that protrudes outward from the outermost end of the second wound electrode.

15. 15. The jelly roll electrode assembly according to claim 9, wherein the first wound electrode is a negative wound electrode.

16. A jelly-roll type electrode assembly having a structure in which a first wound electrode and a second wound electrode are wound with a separator interposed therebetween, an outermost layer of the first wound electrode is located radially outward of the jelly-roll electrode assembly relative to an outermost layer of the second wound electrode; an outermost end of the first wound-type electrode protrudes outward from an outermost end of the second wound-type electrode along a winding direction, the outermost end of the first wound-type electrode being protruded outward from an outermost end of the second wound-type electrode along the winding direction, when the direction in which the first wound-type electrode is wound from the center of the jelly roll-type electrode assembly is defined as the winding direction; the first winding electrode includes a first region including a point of the first winding electrode corresponding to an outermost end of the second winding electrode, and a second region extending from the first region in the winding direction or in a direction opposite to the winding direction; A jelly roll electrode assembly, wherein the first region has a higher elongation rate than the second region.

17. (a) feeding an electrode sheet in a predetermined feeding direction; (b) heating one surface of the electrode sheet in a predetermined region; In the step (b), the electrode sheet is heated to a temperature that increases the elongation of the current collector sheet of the electrode sheet.

18. 18. The electrode sheet heating method of claim 17, wherein the predetermined region includes a region of the electrode sheet corresponding to an end region located at an outermost end of a wound-up electrode in a jelly roll electrode assembly, or a region of the electrode sheet corresponding to a step-occurring region of one of the wound-up electrodes when a step occurs at an outer end of the wound-up electrode due to a difference in length of the wound-up electrodes in the jelly roll electrode assembly.

19. The method for heating an electrode sheet according to claim 17 , further comprising the step of attaching tape to the other surface of the predetermined region of the electrode sheet simultaneously with step (b).

20. 20. The electrode sheet heating method according to claim 17, wherein step (b) is a step of determining a heating temperature based on material properties of the current collector sheet.

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