Electrode sheet heating device, electrode sheet heating method, and wound electrode assembly

Abstract

The present invention relates to an electrode sheet heating device comprising: a heating member provided to heat a lower surface of a predetermined region of an electrode sheet fed in a predetermined feeding direction, in which the electrode sheet is wound and provided to be manufactured as a wound electrode in a wound electrode assembly, the predetermined region may include one region of the electrode sheet corresponding to an end region located at an outermost end of a wound electrode of the wound electrode assembly, or may include one region of the electrode sheet corresponding to an end region located at an outermost end of the wound electrode of the wound electrode assembly when a step is generated at the outermost end of the wound electrode due to a length difference between the wound electrodes of the wound electrode assembly. The predetermined region includes one region of the electrode sheet corresponding to a step generation region in one of the wound electrodes.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Korean Patent Application No. 10-2022-0144042 filed on November 1, 2022 and Korean Patent Application No. 10-2023-0148852 filed on November 1, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to an apparatus and method for heating an electrode sheet, and a wound-type electrode assembly. Background Art

[0004] In general, a secondary battery refers to a rechargeable and dischargeable battery different from a non-rechargeable primary battery, and is widely used in electronic devices such as mobile phones, notebook computers, and video cameras, or electric vehicles, etc. In particular, a lithium secondary battery has a larger capacity and a higher energy density than a nickel-cadmium battery or a nickel-hydrogen battery, and thus its application is rapidly increasing.

[0005] According to the shape of the battery box, secondary batteries can be divided into: cylindrical batteries, prismatic batteries, pouch-type batteries, etc. In cylindrical batteries, the electrode assembly is embedded in a cylindrical metal can, in prismatic batteries, the electrode assembly is embedded in a prismatic metal can, and in pouch-type batteries, the electrode assembly is embedded in a pouch-shaped box made of laminated sheets.

[0006] Figure 1 It is a perspective view showing a general cylindrical battery. Figure 2 yes Figure 1 An exploded perspective view of a cylindrical battery. Figure 1 and Figure 2 As shown in , a cylindrical type battery may include a wound type electrode assembly 20 and a cylindrical case 10 accommodating the wound type electrode assembly 20 .

[0007] The wound electrode assembly 20 may be inserted into the cylindrical case 10 through the opening of the cylindrical case 10. After the insertion, the 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 the cap assembly 30.

[0008] The cap assembly 30 may include a top cap 31 and a safety vent 32. The top cap 31 may be disposed in close contact with the safety vent 32 and may be electrically connected to the safety vent 32. One of the electrodes of the electrode assembly 20 may be electrically connected to the top cap 31 by using the safety vent 32 as a medium.

[0009] The cylindrical type battery may further include a gasket 40 for sealing a gap between the cylindrical case 10 and the cap assembly 30. After the gasket 40 is installed, the upper end portion of the cylindrical case 10 may be bent toward the gasket 40.

[0010] The wound electrode assembly 20 may have a structure in which a first wound electrode and a second wound electrode are wound with a separator therebetween. The wound electrodes may have different lengths. Due to this difference in length, a step portion may be provided between the wound electrodes at the outer end of the wound electrode assembly 20. In a secondary battery, a charge-discharge process may be performed for activation. During this process, the volume of the electrode assembly 20 may expand, and the expansion may cause strong stress to be applied to the portion of the wound electrode that provides the step portion. This may cause damage to the current collector of the wound electrode. Damage to the current collector may cause an increase in battery resistance, thereby increasing the risk of fire caused by heat generation. Summary of the invention

[0011] Technical issues

[0012] An object of the present invention is to provide an apparatus for heating an electrode sheet, a method for heating an electrode sheet, and a wound electrode assembly, wherein, even when a step portion of the wound electrode assembly is provided in any region of a wound electrode of the wound electrode assembly, breakage of a current collector will not occur in the region, or the occurrence of breakage is delayed.

[0013] Technical Solution

[0014] In an embodiment, an apparatus for heating an electrode sheet may include a heating component configured to heat a bottom surface of a predetermined area of ​​an electrode sheet fed along a predetermined feeding direction, wherein the electrode sheet is wound to manufacture a wound electrode of a wound electrode assembly, wherein the predetermined area includes an area of ​​the electrode sheet corresponding to an end area disposed on an outermost end of the wound electrode of the wound electrode assembly, or when a step portion is generated between the outer ends of the wound electrodes due to a length difference between the wound electrodes of the wound electrode assembly, the predetermined area includes an area of ​​the electrode sheet corresponding to an area of ​​one of the wound electrodes where the step portion is generated.

[0015] In another embodiment, the electrode sheet may include a current collector sheet and an active material layer applied on the current collector sheet, and the heating member may heat the predetermined region at a temperature at which an elongation of the current collector sheet increases.

[0016] In yet another embodiment, the heating member may heat the predetermined area at a temperature of 130°C to 150°C.

[0017] In another embodiment, the electrode sheet may include a current collector sheet and an active material layer applied on the current collector sheet, wherein, when the elongation of the current collector sheet disposed on an adjacent area of ​​the electrode sheet adjacent to a predetermined area is 10% or less, the heating component heats the predetermined area so that the current collector sheet disposed in the predetermined area has an elongation of 13% to 20%.

[0018] In still another embodiment, the heating member may include: a support plate extending in a direction crossing the feeding direction to support a bottom surface of the electrode sheet; and a heater heating the support plate.

[0019] In yet another embodiment, the device may further include an attaching member that attaches the belt to a top surface of a predetermined area supported by the support plate.

[0020] In another embodiment, the attachment component may include: a pressing plate, which is arranged to face the support plate and is arranged to move toward the top surface of the electrode sheet; and a driving rod, which allows the pressing plate to move in a direction toward the top surface of the electrode sheet and in a direction opposite to this direction.

[0021] In still another embodiment, the pressing plate may be configured to attach the tape to be attached to the top surface of the electrode sheet to the bottom surface of the pressing plate by adsorption.

[0022] In another embodiment, in a wound electrode assembly having a structure in which a first wound electrode and a second wound electrode are wound with a separator located therebetween, when the direction in which the first wound electrode is wound from the center of the wound electrode assembly is referred to as the winding direction, the elongation of a first region including an end region disposed on the outermost end of the first wound electrode may be higher than the elongation of a second region of the first wound electrode disposed adjacent to the first region in a direction opposite to the winding direction.

[0023] In another embodiment, a first wound electrode may include a first current collector sheet and a first active material layer applied on the first current collector sheet, and a second wound electrode may include a second current collector sheet and a second active material layer applied on the second current collector sheet, wherein the elongation of the first wound electrode and the second wound electrode is obtained based on the elongation of the first current collector sheet and the second current collector sheet, respectively.

[0024] In yet another embodiment, the current collector sheet disposed on the first region may have an elongation of 13% to 20%, and the current collector sheet disposed on the second region may have an elongation of 10% or less.

[0025] In another embodiment, the outermost layer of the first wound electrode can be arranged outside the outermost layer of the second wound electrode in the radial direction of the wound electrode assembly, and the outermost end of the first wound electrode can protrude outward along the winding direction relative to the outermost end of the second wound electrode.

[0026] In yet another embodiment, the first region may include a region of the first wound-type electrode that protrudes outwardly with respect to an outermost end portion of the second wound-type electrode.

[0027] In yet another embodiment, the wound-type electrode assembly may further include a band attached to a region of the first wound-type electrode that protrudes outwardly with respect to an outermost end portion of the second wound-type electrode.

[0028] In yet another embodiment, the first wound electrode may be a wound negative electrode.

[0029] In another embodiment, in a wound electrode assembly having a structure in which a first wound electrode and a second wound electrode are wound with a separator located therebetween, the outermost layer of the first wound electrode can be arranged outwardly relative to the outermost layer of the second wound electrode in the radial direction of the wound electrode assembly, wherein, when the direction in which the first wound electrode is wound from the center of the wound electrode assembly is referred to as the winding direction, the outermost end of the first wound electrode can protrude in the winding direction relative to the outermost end of the second wound electrode, wherein the first wound electrode includes: a first region, the first region including a point of the first wound electrode corresponding to the outermost end of the second wound electrode; and a second region, the second region extending from the first region along the winding direction or in a direction opposite to the winding direction, wherein the elongation of the first region is higher than that of the second region.

[0030] In another embodiment, a method for heating an electrode sheet may include: a step (a) of feeding the electrode sheet along a predetermined feeding direction; and a step (b) of heating a surface of a predetermined area of ​​each of the electrode sheets, wherein, in step (b), the electrode sheet is heated at a temperature that increases the elongation of a current collector sheet of the electrode sheet.

[0031] In yet another embodiment, the predetermined area may include an area of ​​the electrode sheet corresponding to an end area of ​​the outermost end of the wound electrode disposed in the wound electrode assembly. Alternatively, when a step portion is generated between the outer ends of the wound electrodes due to a length difference between the wound electrodes of the wound electrode assembly, the predetermined area may include an area of ​​the electrode sheet corresponding to an area of ​​one of the wound electrodes where the step portion is generated.

[0032] In yet another embodiment, the method for heating the electrode sheet may further include the step of attaching a tape to another surface of the predetermined area of ​​the electrode sheet while performing step (b).

[0033] In yet another embodiment, in step (b), the heating temperature may be determined based on the characteristics of the material of the current collector sheet.

[0034] Beneficial Effects

[0035] According to the present invention, a predetermined area of ​​the electrode sheet can be preheated during the manufacture of the electrode assembly to increase the elongation of the current collector sheet on the area. Therefore, even when the predetermined area of ​​the wound electrode provides a step portion of the wound electrode assembly after the electrode assembly is manufactured, the breakage of the current collector sheet can be prevented or delayed.

[0036] According to the present invention, the first region of the wound electrode of the wound electrode assembly may have a higher elongation than the second region adjacent thereto. Therefore, even if the predetermined region of the wound electrode provides a stepped portion of the wound electrode assembly, breakage of the current collector sheet may be prevented or delayed. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a perspective view showing a general cylindrical battery.

[0038] Figure 2 yes Figure 1 An exploded perspective view of a cylindrical battery in FIG.

[0039] Figure 3 1 is a perspective view illustrating an apparatus for manufacturing a wound electrode assembly to which the apparatus for heating an electrode sheet according to Embodiment 1 of the present invention is applied.

[0040] Figure 4 is a graph showing the elongation of copper as a function of temperature.

[0041] Figure 5 is a cross-sectional view illustrating a wound-type electrode assembly according to Embodiment 2 of the present invention.

[0042] Figure 6 It's a picture. Figure 5 A cross-sectional view of a modified example of a wound electrode assembly in FIG. DETAILED DESCRIPTION

[0043] Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. However, the present invention can be implemented in different forms and should not be construed as being limited to the embodiments described herein.

[0044] In order to clearly describe the present invention, detailed description of related well-known technologies that are irrelevant to the description or that may unnecessarily obscure the subject matter of the present invention will be excluded. Throughout the specification, the same reference numerals refer to the same elements.

[0045] Furthermore, the terms or words used in the specification and claims should not be restrictively interpreted as ordinary meanings or dictionary-based meanings, but should be interpreted as meanings and concepts consistent with the scope of the present invention based on the principle that the inventor can appropriately define the concepts of the terms in order to best describe and interpret his or her invention.

[0046] Implementation Method 1

[0047] Figure 3 1 is a perspective view illustrating an apparatus for manufacturing a wound electrode assembly to which the apparatus for heating an electrode sheet according to Embodiment 1 of the present invention is applied.

[0048] like Figure 3 As shown in FIG. 1 , the first separator sheet S1, the first electrode sheet 110, the second separator sheet S2, and the second electrode sheet 120 which are continuously supplied may be wound around a predetermined winding center C to manufacture a wound electrode assembly A. Through this process, the wound electrode assembly A may have a first wound electrode 210 (see FIG. 1 ). Figure 5 ) and a second wound electrode 220 (see Figure 5 ) in the separators 271, 272 (see Figure 5 ) is located therebetween. After winding, the first electrode sheet 110 may be cut to provide a portion of the wound electrode assembly 200 (see Figure 5 ), and thus can be manufactured as the first wound electrode 210 of the wound electrode assembly 200. The same applies to the second electrode sheet 120.

[0049] 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 on the first current collector sheet 111. The first current collector sheet 111 may include copper foil, etc., but the first current collector sheet 111 is not limited thereto.

[0050] 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 on the second current collector sheet 121. The second current collector sheet 121 may include aluminum foil, etc., but the second current collector sheet 121 is not limited thereto.

[0051] Device 100 for heating electrode sheets

[0052] The apparatus 100 for heating an electrode sheet (hereinafter referred to as a heating apparatus) according to this embodiment may include a heating member 130 provided to heat a bottom surface of a predetermined region 110 a of an electrode sheet 110 fed in a predetermined feeding direction F.

[0053] Figure 3 The diagram shows a heating device 100 for heating the first electrode sheet 110 of the first electrode sheet 110 and the second electrode sheet 120. The heating device 100 may also be configured to heat the second electrode sheet 120. Hereinafter, a case where the heating device 100 heats the first electrode sheet 110 will be described. In addition, Figure 3 The heating device 100 is illustrated to heat the bottom surface of the first electrode sheet 110. The heating device 100 may also be configured to heat the top surface of the first electrode sheet 110. For reference, the feeding direction F may be a direction in which the electrode sheet 110 is conveyed to the winding center C so as to be wound.

[0054] The predetermined area 110a of the first electrode sheet 110 may include the first electrode sheet 110 and the predetermined area 110a of the first electrode sheet 110 disposed in the wound electrode assembly 200 (see Figure 5 ) of the first wound electrode 210 (see Figure 5 ). For example, when the predetermined area 110a of the first electrode sheet 110 is wound to provide the wound electrode assembly 200, the predetermined area 110a of the first electrode sheet 110 may be any area of ​​the first electrode sheet 110 that provides the end area 210a of the first wound electrode 210 of the wound electrode assembly 200.

[0055] like Figure 5 As shown in , in the wound electrode assembly 200, the outermost layer of the first wound electrode 210 may be disposed outwardly relative to the outermost layer of the second wound electrode 220 in the radial direction D1 of the wound electrode assembly A. The outermost end 210c of the first wound electrode 210 may protrude outwardly relative to the outermost end 220c of the second wound electrode 220 along the winding direction D2. The end region 210a of the first wound electrode 210 may include a portion disposed outwardly relative to the outermost end 220c of the second wound electrode 220 along the winding direction D2, or may include the portion and a portion disposed inwardly relative to the outermost end 220c of the second wound electrode 220 along the direction D3 opposite to the winding direction. The total length of the first wound electrode 210 may be longer than the total length of the second wound electrode 220. For reference, the winding direction D2 may be the direction in which the first wound electrode 210 is wound from the center of the wound electrode assembly 200. In the wound type electrode assembly 200 , due to the above-described structure, the step portion R may be provided on the end portion in the winding direction D2 .

[0056] The volume of the electrode assembly 200 may expand during the charge and discharge process for activation. However, when the volume expands, strong stress may be applied to the portion of the first wound electrode 210 where the step portion R is provided. This may cause the first current collector sheet 111 (see FIG. 1 ) of the first wound electrode 210 to be Figure 3 ) is damaged. Damage to the first current collector sheet 111 may increase the battery resistance, thereby increasing the risk of fire caused by heat.

[0057] During the manufacture of the wound electrode assembly A, the heating device 100 according to this embodiment may preheat a predetermined region 110a of the electrode sheet 110 corresponding to the end region 210a of the first wound electrode 210 (see Figure 3 ), which can provide the aforementioned step portion R of the wound electrode assembly 200. Therefore, the elongation of the first current collector sheet 111 of the first wound electrode 210 can be increased in the end region 210a of the first wound electrode 210 (see Figure 5 ), and therefore, it is possible to prevent or delay the breakage of the first current collector sheet 111. This is because copper or the like constituting the first current collector sheet 111 has the following characteristics: when copper or the like is heated at a specific temperature, the elongation increases, and when the elongation increases, the energy required for plastic failure also increases, and therefore, it is difficult to break.

[0058] As described above, during the manufacture of the wound electrode assembly A, the heating device 100 according to this embodiment may preheat the predetermined area 110a of the electrode sheet 110 (see Figure 3 ), so that the elongation of the current collector sheet 111 in the region increases, the predetermined region 110a includes a region of the electrode sheet 110 corresponding to the end region 210a of the wound electrode 210. Therefore, even when the end region 210a of the wound electrode 210 provides the step portion R of the electrode assembly 200 after manufacturing the electrode assembly 200, the breakage of the current collector sheet 111 can be prevented or delayed.

[0059] Heating element 130

[0060] like Figure 3 As shown in FIG. 1 , the heating device 100 according to the embodiment may include a heating member 130 to heat a predetermined region 110a of the electrode sheet 110. Hereinafter, the heating member 130 will be described in detail.

[0061] The heating component 130 may include a support plate 131, which is arranged to extend in a direction intersecting the feeding direction F (for example, a direction perpendicular to the feeding direction) and support the bottom surface of the electrode sheet 110. The support plate 131 may be arranged to move vertically so as to be in close contact with the bottom surface of the electrode sheet 110. Alternatively, the support plate 131 may be fixed to a position in close contact with the bottom surface of the electrode sheet 110. The heating component 130 may include a heater 132 arranged to heat the support plate 131. The heater 132 may be a coil heater embedded in the support plate 131. The heating component 130 may control the heater 132 to heat the support plate 131 so that the electrode sheet 110 supported by the support plate 131 is heated at a predetermined temperature.

[0062] The heating member 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 member 130 may heat the predetermined region 110a of the electrode sheet 110 at a temperature of 130°C to 150°C. Figure 4 As shown in , when the current collector sheet 111 is made of copper foil, this temperature range may be effective. Figure 4 is a graph showing the elongation of copper as a function of temperature. In copper materials, when the copper material is heated at a temperature of 130° C. to 150° C., its elongation may be relatively greatly increased. The temperature range in which the heating member 130 heats the predetermined area 110 a may vary according to the characteristics of the material constituting the current collector sheet 111.

[0063] When the elongation of the current collector sheet 111 disposed on 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 member 130 may heat the predetermined region 110a so that the current collector sheet disposed in the predetermined region 110a has an elongation of 13% to 20%.

[0064] For reference, the elongation can be measured using a tensile testing machine. For example, the elongation of the current collector sheet (the percentage of the current collector sheet stretched) can be measured by obtaining a predetermined length (e.g., 10 mm to 15 mm) of the heat-treated current collector sheet, and then measuring its stretched length while stretching the current collector sheet along one axis (e.g., at a speed of 50 mm / min) until the current collector sheet breaks.

[0065] Attachment member 140

[0066] like Figure 3As shown in FIG. 1 , the heating device 100 according to this embodiment may include an attachment member 140 configured to attach the tape 150 to the top surface of the predetermined area 110a of the electrode sheet 110 supported by the support plate 131. As described above, the current collector sheet is easily attached to the step portion R (see FIG. 1 ) of the electrode assembly 200. Figure 5 ), but when the tape 150 is pre-attached to this area during the manufacture of the electrode assembly A, the occurrence of breakage as described above can be prevented or delayed.

[0067] The attachment member 140 may include a pressing plate 141 disposed to face the support plate 131 and to move toward the top surface of the electrode sheet 110. The attachment member 140 may include a driving rod 142 disposed to move the pressing plate 141 in a direction toward the top surface of the electrode sheet 110 and in a direction opposite to the direction. The pressing plate 141 may be moved to the top surface of the electrode sheet 110 supported by the support plate 131 by the driving rod 142 so that the belt 150 is attached to the top surface of the electrode sheet 110. The pressing plate 141 may move until the support plate 131 is pressed with the belt 150 located between the pressing plate 141 and the support plate 131.

[0068] The pressing plate 141 may selectively attach the tape 150 to its bottom surface, and for this purpose, the pressing plate 141 may have a structure that adsorbs the tape 150. For example, the tape 150 may be attached to the bottom surface of the pressing plate 141 by adsorption, and the tape 150 may be detached from the bottom surface of the pressing plate 141 by releasing the adsorption.

[0069] The tape attaching device for attaching the tape 150 to the top surface of the electrode sheet 110 may include a pressing plate 141 for pressing to attach the tape 150 and a support plate 131 for supporting the bottom surface of the electrode sheet 110 during the pressing of the pressing plate 141. When a heating function is given to the support plate 131 of the attaching device, attachment of the tape 150 and heating of the electrode sheet 110 can be achieved simultaneously.

[0070] Method for heating electrode sheets

[0071] The electrode sheet 110 can be heated through the following series of operations.

[0072] First, the electrode sheet 110 may be fed in a predetermined feeding direction. One surface (e.g., bottom surface) of a predetermined region 110a of the electrode sheet 110 may be heated during feeding or during feeding interruption. The electrode sheet 110 may be heated at a temperature at which the elongation of the current collector sheet 111 of the electrode sheet 110 increases. The heating temperature may be determined based on the characteristics of the material of the current collector sheet 111.

[0073] The predetermined area 110a of the electrode sheet 110 may include an area of ​​the electrode sheet 110 corresponding to an end area on the outermost end of the wound electrode provided in the wound electrode assembly. Alternatively, when a step portion is generated between the outer ends of the wound electrodes due to a length difference between the wound electrodes of the wound electrode assembly, the predetermined area 110a of the electrode sheet 110 may include an area of ​​the electrode sheet 110 corresponding to an area of ​​one of the wound electrodes where the step portion is generated. For example, the area where the step portion is generated may be defined as including a point P1 of the first wound electrode 210 corresponding to the outermost end 220c of the second wound electrode 220 in the electrode assembly (see Figure 6 ).

[0074] The tape may be attached to the other surface (eg, the top surface) of the predetermined region 110 a of the electrode sheet 110 while the predetermined region 110 a of the electrode sheet 110 is heated.

[0075] Implementation Method 2

[0076] Figure 5 2 is a cross-sectional view illustrating a wound electrode assembly according to Embodiment 2 of the present invention. The wound electrode assembly 200 according to Embodiment 2 may be an electrode assembly 200 in which an electrode sheet heat-treated by the heating device 100 according to Embodiment 1 is employed. However, the electrode sheet applied to the wound electrode assembly 200 according to Embodiment 2 is not limited to the electrode sheet heat-treated by the heating device 100 according to Embodiment 1.

[0077] The wound electrode assembly 200 according to this embodiment may have a structure in which first and second wound electrodes 210 and 220 are wound with separators 271 and 272 therebetween. The first wound electrode 210 may be a wound negative electrode, and the second wound electrode 220 may be a wound positive electrode.

[0078] The first wound electrode 210 may include a first region 261 including an end region 210a disposed on the outermost end 210c of the first wound electrode 210. The first region 261 may be the same as the end region 210a, and may include the end region 210a and be wider than the end region 210a. The first wound electrode 210 may include a second region 262 of the first wound electrode 210, which is disposed adjacent to the first region 261 in a direction D3 opposite to the winding direction.

[0079] The first region 261 may be a region having a length of 3 cm to 6 cm in the winding direction D2 of the first wound electrode 210. The length of the first region 261 may be a range that allows the tape to be attached. The first region 261 may be a region having a length corresponding to 5% to 10% of the entire length of the first wound electrode 210 in the winding direction D2.

[0080] In this embodiment, the elongation of the first region 261 of the first wound electrode 210 may be higher than the elongation of the second region 262. The elongations of the first and second wound electrodes 210 and 220 may be based on the first and second current collector sheets 111 and 121 constituting the first and second wound electrodes 210 and 220, respectively (see Figure 3 For example, the elongation of the first current collector sheet 111 may be considered as the elongation of the first wound electrode 210 .

[0081] Since the first region 261 of the wound electrode 210 including the end region 210a of the wound electrode 210 has a higher elongation than the second region 262 adjacent thereto, the wound electrode assembly 200 according to this embodiment can prevent or delay the breakage of the current collector sheet 111 even when the end region 210a of the wound electrode 210 provides a step portion R of the wound electrode assembly 200.

[0082] In the first wound electrode 210 of the wound electrode assembly 200 according to this embodiment, the current collector sheet 111 disposed in the first region 261 may have an elongation of 13% to 20%, and the current collector sheet 111 disposed in the second region 262 may have an elongation of 10% or less.

[0083] The outermost layer of the first wound electrode 210 may be disposed outwardly relative to the outermost layer of the second wound electrode 220 in the radial direction D1 of the wound electrode assembly 200. The outermost end 210c of the first wound electrode 210 may protrude outwardly relative to the outermost end 220c of the second wound electrode 220 in the winding direction D2. Due to this structure, a step portion R may be provided in the wound electrode assembly 200.

[0084] The first region 261 of the first wound electrode 210 may include a region of the first wound electrode 210 that protrudes outward relative to the outermost end 220c of the second wound electrode 220 (hereinafter referred to as a protruding region, for example, Figure 5The protruding region 210a of the first wound electrode 210 may be a region where the step portion R is provided, and thus the first region 261 including the entire protruding region 210a may be configured to have a higher elongation than other regions to prevent breakage. Figure 5 The first region 261 may be the same as the region 210a in the figure, or may be a part of the region 210a. The first region 261 may be defined as a region including the entire protruding region, or including the entire protruding region and a region extending from the protruding region.

[0085] The electrode assembly 200 according to the embodiment may further include a tape 250 attached to the protruding region of the first wound type electrode 210. When the tape 250 attached to the protruding region is further provided, the occurrence of breakage may be more effectively prevented.

[0086] The first area and the second area can be as follows Figure 6 Definition shown. Figure 6 It's a picture. Figure 5 A cross-sectional view of a modified example of a wound electrode assembly in FIG. With respect to the positions of the first region and the second region, Figure 6 The electrode assembly 200' is different from Figure 5 The electrode assembly 200 in.

[0087] exist Figure 6 In the electrode assembly 200', the first region 261' may be defined as a point P1 corresponding to the outermost end 220c of the second wound electrode 220 including the first wound electrode 210. The second region 262' may be a region extending from the first region 261' along the winding direction D2 or in a direction opposite to the winding direction. Here, the elongation of the first region 261' may be higher than the elongation of the second region 262'. In the step portion of the electrode assembly, the most stressed portion of the first wound electrode 210 may be a point P1 of the first wound electrode 210 corresponding to the outermost end 220c of the second wound electrode 220. In this modified example, taking this issue into consideration, the first region 261' may be defined as above. The same definition of the first region and the second region (predetermined region and adjacent region) as described above may be applied to the heating device according to the above-described embodiment 1.

[0088] The description of the present invention is intended to be illustrative and various changes and modifications may be made by one skilled in the art to which the present invention pertains without departing from the spirit and scope of the present invention as defined in the following claims.

[0089] Therefore, the embodiments described herein are intended to describe the technical spirit of the present invention, rather than to limit it. The scope of the technical spirit of the present invention is not limited by the embodiments.

[0090] In addition, the protection scope of the present invention should be determined by reasonable interpretation of the appended claims, and all technical concepts within the equivalent scope of the present application should be interpreted as belonging to the scope of rights of the present application.

Claims

1. A device for heating an electrode sheet, the device include: a heating member configured to heat a bottom surface of a predetermined area of ​​the electrode sheet fed in a predetermined feeding direction, wherein the electrode sheet is wound to produce a wound electrode of a wound electrode assembly, wherein the predetermined area includes an area of ​​the electrode sheet corresponding to an end area disposed on the outermost end of the wound electrode of the wound electrode assembly, or When a step portion is generated between outer ends of the wound electrodes due to a length difference between the wound electrodes of the wound electrode assembly, the predetermined area includes an area of ​​the electrode sheet corresponding to an area of ​​one of the wound electrodes where the step portion is generated.

2. The device for heating an electrode sheet according to claim 1, in, The electrode sheet includes a current collector sheet and an active material layer applied on the current collector sheet, wherein the heating member is configured to heat the predetermined region at a temperature at which an elongation of the current collector sheet increases.

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

4. The device for heating an electrode sheet according to claim 1, in, The electrode sheet includes a current collector sheet and an active material layer applied on the current collector sheet, Wherein, when the elongation of the current collector sheet disposed on an adjacent area of ​​the electrode sheet adjacent to the predetermined area is 10% or less, the heating component is configured to heat the predetermined area so that the current collector sheet disposed in the predetermined area has an elongation of 13% to 20%.

5. The device for heating an electrode sheet according to claim 1, in, The heating component comprises: a support plate extending in a direction intersecting the feeding direction to support a bottom surface of the electrode sheet; and A heater is configured to heat the support plate. 6 . The apparatus for heating an electrode sheet according to claim 5 , further comprising an attaching member configured to attach a tape to a top surface of the predetermined area supported by the support plate.

7. The device for heating an electrode sheet according to claim 6, in, The attachment member comprises: a pressing plate disposed to face the support plate and configured to move toward a top surface of the electrode sheet; and A driving rod configured to allow the pressing plate to move in a direction toward a top surface of the electrode sheet and in a direction opposite to the direction.

8. The device for heating an electrode sheet according to claim 7, in, The pressing plate is configured to attach a tape to be attached to a top surface of the electrode sheet to a bottom surface of the pressing plate by adsorption.

9. A wound electrode assembly having a structure in which a first wound electrode and a second wound electrode are wound with a separator therebetween, in, When the direction in which the first wound electrode is wound from the center of the wound electrode assembly is called the winding direction, the elongation of a first region including an end region arranged on the outermost end of the first wound electrode is higher than the elongation of a second region of the first wound electrode arranged adjacent to the first region in a direction opposite to the winding direction.

10. The wound electrode assembly according to claim 9, in, The first wound electrode includes a first current collector sheet and a first active material layer applied on the first current collector sheet, and the second wound electrode comprises a second current collector sheet and a second active material layer applied on the second current collector sheet, The elongations of the first wound electrode and the second wound electrode are obtained based on the elongations of the first current collector sheet and the second current collector sheet, respectively.

11. The wound electrode assembly according to claim 10, in, The current collector sheet disposed on the first region has an elongation of 13% to 20%, and The current collector sheet disposed on the second region has an elongation of 10% or less.

12. The wound electrode assembly according to claim 10, in, The outermost layer of the first wound electrode is arranged outwardly relative to the outermost layer of the second wound electrode in the radial direction of the wound electrode assembly, and The outermost end portion of the first wound electrode protrudes outwardly in the winding direction relative to the outermost end portion of the second wound electrode.

13. The wound electrode assembly according to claim 12, in, The first region includes a region of the first wound electrode that protrudes outward relative to an outermost end portion of the second wound electrode. 14 . The wound type electrode assembly according to claim 12 , further comprising a tape attached to a region of the first wound type electrode protruding outwardly with respect to an outermost end portion of the second wound type electrode.

15. The wound electrode assembly according to claim 9, in, The first wound electrode is a wound negative electrode.

16. A wound electrode assembly having a structure in which a first wound electrode and a second wound electrode are wound with a separator therebetween, in, The outermost layer of the first wound electrode is arranged outwardly relative to the outermost layer of the second wound electrode in the radial direction of the wound electrode assembly. When the direction in which the first wound electrode is wound from the center of the wound electrode assembly is referred to as a winding direction, the outermost end of the first wound electrode protrudes relative to the outermost end of the second wound electrode in the winding direction. Wherein, the first wound electrode comprises: a first region including a point of the first wound electrode corresponding to an outermost end portion 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, Wherein, the elongation of the first region is higher than the elongation of the second region.

17. A method for heating an electrode sheet, the method include: A step (a) of feeding the electrode sheet in a predetermined feeding direction; as well as step (b) of heating a surface of a predetermined area of ​​the electrode sheet, Wherein, in the step (b), the electrode sheet is heated at a temperature at which the elongation of the current collector sheet of the electrode sheet increases.

18. The method for heating an electrode sheet according to claim 17, in, The predetermined area includes an area of ​​the electrode sheet corresponding to an end area provided on the outermost end of the wound electrode of the wound electrode assembly; or When a step portion is generated between outer ends of the wound electrodes due to a length difference between the wound electrodes of the wound electrode assembly, the predetermined area includes an area of ​​the electrode sheet corresponding to an area where the step portion is generated in one of the wound electrodes.

19. The method for heating an electrode sheet according to claim 17, further comprising attaching a tape to another surface of the predetermined area of ​​the electrode sheet while performing the step (b).

20. The method for heating an electrode sheet according to claim 17, in, In the step (b), the heating temperature is determined based on the characteristics of the material of the current collector sheet.

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