Electrode manufacturing method, electrode, and battery cell including same

Abstract

An electrode manufacturing method according to the present invention is a method for manufacturing an electrode having, at a long side on one side thereof, an uncoated portion extending in the longitudinal direction of the long side, the method comprising the steps of: (a) arranging a camber prevention member in a first region of an electrode sheet in which the uncoated portion is to be formed; (b) coating at least a second region of the electrode sheet with a slurry to form an active material layer thereon, wherein the second region is a region excluding the first region of the electrode sheet; (c) rolling the electrode sheet having the active material layer formed thereon so that both the first region and the second region of the electrode sheet are stretched; (d) slitting the rolled electrode sheet; (e) storing the slit electrode sheet; and (f) removing the camber prevention member from the electrode sheet to form the uncoated portion, and then notching the uncoated portion.

Description

Method for manufacturing an electrode, an electrode, and a battery cell including the same

[0001] The present invention relates to a method for manufacturing an electrode, an electrode, and a battery cell including the same, and more specifically, to a method for manufacturing an electrode, an electrode, and a battery cell including the same that can improve the quality of the electrode and minimize the defect rate.

[0002] This application is a priority claim application for Korean Patent Application No. 10-2024-0136975 filed on October 8, 2024, and all contents disclosed in the specification of said application are incorporated into this application by reference.

[0003] Recently, as the demand for portable electronic products such as laptops, video cameras, and mobile phones has increased rapidly, and the development of electric vehicles, energy storage batteries, robots, and satellites has accelerated, research on high-performance secondary batteries capable of repeated charging and discharging is actively underway.

[0004] Currently commercialized rechargeable batteries include nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, and lithium-ion batteries. Among these, lithium-ion batteries are gaining attention for their advantages, such as the ability to freely charge and discharge with almost no memory effect compared to nickel-based batteries, a very low self-discharge rate, and high energy density.

[0005] These lithium-ion secondary batteries primarily use lithium-based oxides and carbon materials as the positive and negative active materials, respectively. Additionally, the lithium-ion secondary battery comprises an electrode assembly in which a positive plate and a negative plate, each coated with the positive and negative active materials, are arranged with a separator in between, and an outer casing that seals and encloses the electrode assembly together with an electrolyte.

[0006] Meanwhile, lithium-ion secondary batteries can be classified according to the shape of the battery case into pouch-type secondary batteries, in which the electrode assembly is embedded in a pouch made of aluminum laminate sheets, and can-type secondary batteries, in which the electrode assembly is embedded in a metal can. Furthermore, can-type secondary batteries can be further classified into cylindrical batteries and prismatic batteries depending on the shape of the metal can.

[0007] In addition, the electrode assembly embedded in the battery case is a power generation element capable of charging and discharging, comprising a stacked structure of a positive electrode, a separator, and a negative electrode. Examples include a jelly-roll type electrode assembly wound with a separator interposed between long sheet-type positive and negative electrodes coated with active material, a stack type electrode assembly sequentially stacked with a separator interposed between multiple positive and negative electrodes cut into units of a predetermined size, and a stack / folding type electrode assembly having a structure of winding bi-cells or full cells stacked with a separator interposed between units of positive and negative electrodes.

[0008] Generally, the electrodes, which are the positive and negative electrodes of an electrode assembly, undergo a process of coating a slurry containing an electrode active material onto a current collector in a predetermined pattern and thickness to stack an electrode active material layer, a process of rolling the current collector with the stacked active material layer, and a process of slitting the rolled current collector, and are then stored for a predetermined period before being fed into a winder. In addition, a notching-type electrode having a so-called notching tab in the uncoated portion can be notched immediately before being fed into a winder.

[0009] However, according to conventional electrode manufacturing methods, there was a high possibility of a so-called sliding phenomenon occurring during the coating process, where the slurry spreads to the uncoated area and forms at an angle. When such a sliding phenomenon occurs, there is a problem that the N / P ratio may decrease or reverse, and lithium (Li) may precipitate.

[0010] In addition, according to the conventional electrode manufacturing method, there is a difference in thickness between the retaining portion where the active material layer is stacked and the unstacking portion where the active material layer is not stacked. Consequently, during the rolling process of the current collector where the active material layer is stacked, a difference in the amount of elongation between the retaining portion and the unstacking portion occurs, and due to this difference in the amount of elongation by position, a camber phenomenon such as bending or ripple occurs in the electrode.

[0011] In addition, in the case of electrodes manufactured by conventional electrode manufacturing methods, there was also a problem in that the current collector was stored for a long period of time from rolling and slitting until just before being fed into the winder, and various stresses such as circumferential stress were continuously applied to the electrode, causing the camber to deepen over time.

[0012] As mentioned above, if camber occurs or intensifies in the electrode, the quality of the electrode may deteriorate and the defect rate may increase. Furthermore, when such electrodes are wound to manufacture battery cells, meandering defects may occur, potentially leading to stability issues such as internal combustion within the battery cell.

[0013] The present invention was devised in consideration of the aforementioned problems and aims to provide a method for manufacturing an electrode that can prevent the sliding phenomenon of an active material layer, an electrode, and a battery cell including the same.

[0014] In addition, another objective is to provide a method for manufacturing an electrode, an electrode, and a battery cell including the same, which can improve the quality of the electrode and minimize the defect rate by preventing the occurrence of camber phenomena.

[0015] In addition, another objective is to provide a method for manufacturing an electrode, an electrode, and a battery cell including the same, which can effectively prevent the deepening of camber due to aging even during long-term storage.

[0016] The technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems will be clearly understood by those skilled in the art from the description of the invention below.

[0017] A method for manufacturing an electrode according to the present invention is a method for manufacturing an electrode in which a non-solid portion is extended and formed along the length direction of one long side, comprising: (a) a step in which a camber prevention member is disposed in a first region where the non-solid portion of the electrode sheet is to be formed; (b) a step in which a slurry is coated on at least the second region of the electrode sheet, and an active material layer is laminated, wherein the region excluding the first region of the electrode sheet is a second region; (c) a step in which the electrode sheet with the laminated active material layer is rolled so that both the first region and the second region of the electrode sheet are stretched; (d) a step in which the rolled electrode sheet is slit; (e) a step in which the slit electrode sheet is stored; and (f) a step in which the camber prevention member is removed from the electrode sheet to form the non-solid portion, and then the non-solid portion is notched.

[0018] Additionally, step (e) is a step in which the slit electrode sheet is stored for a first time period, and step (f) is carried out for a second time period from the time when step (e) is completed, and the first time period may be longer than the second time period.

[0019] Additionally, the camber prevention member is provided in the form of a strip corresponding to the unoccupied portion, and in step (a), the camber prevention member can be attached to the first region of the electrode sheet.

[0020] The above camber prevention member may include at least one material selected from polypropylene, polyimide, and polyethylene terephthalate.

[0021] In step (b) above, the total thickness of the first region and the total thickness of the second region can be formed to be approximately the same as each other.

[0022] In step (b) above, the slurry may be coated on both the second region of the electrode sheet and the outer surface of the camber prevention member.

[0023] The electrode sheet rolled in step (c) above can be formed such that the thickness of the first region and the thickness of the second region are the same.

[0024] The above step (d) may include a step (d-1) in which the first region of the electrode sheet is slit.

[0025] In step (e) above, the electrode sheet can be stored in a wound state.

[0026] In step (e) above, the electrode sheets can be stored in a stacked state.

[0027] The above camber prevention member may be composed of a plurality of layers.

[0028] The camber prevention member may be provided such that one layer of the camber prevention member and another layer of the camber prevention member have different physical properties.

[0029] The electrode according to the present invention is manufactured by the electrode manufacturing method according to the present invention.

[0030] A battery cell according to the present invention comprises at least one electrode according to the present invention.

[0031] According to the present invention, a method for manufacturing an electrode in which a sliding phenomenon of an active material layer can be prevented, an electrode, and a battery cell including the same can be provided.

[0032] In addition, a method for manufacturing an electrode, an electrode, and a battery cell including the same can be provided, which can improve the quality of the electrode and minimize the defect rate by preventing the occurrence of camber phenomena.

[0033] In addition, a method for manufacturing an electrode, an electrode, and a battery cell including the same can be provided, which can effectively prevent the deepening of camber due to aging even during long-term storage.

[0034] The effects of the present invention are not limited to the effects described above, and unmentioned effects will be clearly understood by those skilled in the art from this specification and the attached drawings.

[0035] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0036] FIG. 1 is a perspective view showing the external appearance of a battery cell according to one embodiment of the present invention.

[0037] FIG. 2 is a side cross-sectional view showing the interior of a battery cell according to one embodiment of the present invention.

[0038] FIG. 3 is a side view showing an electrode unfolded according to one embodiment of the present invention.

[0039] FIG. 4 is a flowchart showing the overall process of an electrode manufacturing method according to one embodiment of the present invention.

[0040] FIG. 5 is a conceptual diagram conceptually illustrating the overall process of an electrode manufacturing method according to one embodiment of the present invention.

[0041] FIG. 6 is a timeline of an electrode manufacturing method according to one embodiment of the present invention.

[0042] FIG. 7 shows the appearance of an electrode sheet after step (a) of an electrode manufacturing method according to one embodiment of the present invention.

[0043] FIG. 8 shows the appearance of an electrode sheet after step (b) of the electrode manufacturing method according to one embodiment of the present invention.

[0044] FIG. 9 is a cross-sectional view showing the appearance of an electrode sheet after step (b) of an electrode manufacturing method according to a modified example of an embodiment of the present invention.

[0045] FIG. 10 shows the appearance of an electrode sheet after step (c) of an electrode manufacturing method according to one embodiment of the present invention.

[0046] FIG. 11 shows the appearance of an electrode sheet after step (d) of the electrode manufacturing method according to one embodiment of the present invention.

[0047] FIG. 12 shows the electrode sheet being stored in step (e) of the electrode manufacturing method according to one embodiment of the present invention.

[0048] FIG. 13 shows how an electrode sheet is stored in step (e) of an electrode manufacturing method according to another variation of one embodiment of the present invention.

[0049] FIGS. 14 and 15 show the appearance of an electrode sheet after step (f) of an electrode manufacturing method according to one embodiment of the present invention.

[0050] FIG. 16 is a cross-sectional view showing the appearance of an electrode sheet after step (c) of an electrode manufacturing method according to another embodiment of the present invention.

[0051] FIG. 17 is a cross-sectional view showing the appearance of an electrode sheet after step (c) of an electrode manufacturing method according to another embodiment of the present invention.

[0052] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, and should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0053] Therefore, it should be understood that the embodiments described in this specification and the configurations illustrated in the drawings are merely some of the most preferred embodiments of the invention and do not represent all of the technical ideas of the invention, and that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0054]

[0055] FIG. 1 is a perspective view showing the external appearance of a battery cell according to one embodiment of the present invention, FIG. 2 is a side cross-sectional view showing the interior of a battery cell according to one embodiment of the present invention, and FIG. 3 is a side view showing an electrode unfolded according to one embodiment of the present invention.

[0056] Hereinafter, with reference to FIGS. 1 to 3, a battery cell and an electrode applied to the present invention will be described.

[0057] In particular, referring to FIGS. 1 and FIGS. 2, the battery cell (1) to which the present invention applies may include an electrode assembly (10) and a cell housing (20).

[0058] The electrode assembly (10) may include an electrode (11) and a separator (12). The electrode (11) may include a first electrode (11a) and a second electrode (11b). The separator (12) may be interposed between the first electrode (11a) and the second electrode (11b). The first electrode (11a) may be an electrode (11) having a first electrode, and the second electrode (11b) may be an electrode (11) having a second electrode (11b) with a polarity opposite to that of the first electrode. For example, the first electrode (11a) may be a positive electrode and the second electrode (11b) may be a negative electrode. The separator (12) may be an insulator.

[0059] The electrode assembly (10) may have a jelly-roll structure. That is, the electrode assembly (10) may be manufactured by winding a laminate formed by stacking a first electrode (11a) and a second electrode (11b) having a sheet shape at least once with a separator (12) interposed between them, based on a winding center axis (C). Any jelly-roll structure known in the art may be applied to the present invention without limitation.

[0060] The cell housing (20) may be configured to accommodate the electrode assembly (10). The cell housing (20) may be provided, for example, in a hollow cylindrical shape to accommodate the electrode assembly (10).

[0061] A closed portion may be formed on one side of the cell housing (20) (e.g., the Z-direction side). An open portion may be formed on the other side of the cell housing (20) (e.g., the -Z-direction side), and a cap (30) covering the open portion may be disposed therein.

[0062] A first current collector plate (40) may be disposed on the inner side of one side (Z-direction side) of the cell housing (20). The first current collector plate (40) may be electrically connected to the first electrode (11a). The first current collector plate (40) may be electrically connected to the terminal (60) described later.

[0063] A second current collector plate (50) may be disposed on the inner side of the other side (-Z direction side) of the cell housing (20). The second current collector plate (50) may be electrically connected to the second electrode (11b). The second current collector plate (50) may be electrically connected to the cell housing (20), and the cell housing (20) may have the second electrode (11b).

[0064] A terminal (60) may be disposed on one side (Z-direction side) of the cell housing (20). The terminal (60) may be disposed through one side (Z-direction side) of the cell housing (20) with at least a portion exposed to the outside. The terminal (60) may have a first electrode by being electrically connected to the first electrode (11a). The terminal (60) may be provided in the form of a rivet.

[0065] An insulating gasket (70) may be placed between the terminal (60) and the cell housing (20). The insulating gasket (70) can insulate the terminal (60) and the cell housing (20) from each other.

[0066] An insulator (80) may be placed between the first collector plate (40) and the cell housing (20). The insulator (80) can insulate the first collector plate (40) and the cell housing (20) from each other.

[0067]

[0068] In particular, with reference to FIG. 3, the electrode (11) provided in the electrode assembly (10) of the battery cell (1) according to the present invention will be described in more detail. The electrode (11) shown in FIG. 3 may be a first electrode (11a) or a second electrode (11b).

[0069] The electrode (11) may have a predetermined length and width. The electrode (11) may have a predetermined length in the X-axis direction. The +X direction may be a direction toward the outer circumference of the electrode assembly (10), and the -X direction may be a direction toward the winding center axis (C). The electrode (11) may have a predetermined width in the Z-axis direction.

[0070] The electrode (11) may be provided with a retaining portion (111) and a non-retaining portion (112). The retaining portion (111) may be a portion on one or both sides of the electrode (11) where an active material is laminated. A positive active material may be laminated on the retaining portion (111) of the first electrode (11a), and a negative active material may be laminated on the retaining portion (111) of the second electrode (11b).

[0071] The unused portion (112) may be a part of the electrode (11) where no active material is laminated. The unused portion (112) may be formed on one long side of the electrode (11) having a predetermined length. That is, the unused portion (112) may be formed at one end of the electrode (11) in the width direction (Z-axis direction). When the electrode (11) is the first electrode (11a), the unused portion (112) may be formed on the long side of the electrode (11) in the +Z direction, as shown in FIG. 3. When the electrode (11) is the second electrode (11b), the unused portion (112) may be formed on the long side of the electrode (11) in the -Z direction, unlike as shown in FIG. 3. The unused portion (112) may be formed by extending along the length direction of the electrode (11). For example, the unused portion (112) may be formed in a strip shape by extending along the X direction.

[0072] The unseen portion (112) may be exposed to the outside of the separator (12). The unseen portion (112) may be used as an electrode tab. The unseen portion (112) may be provided with a plurality of foil tabs (113). At least one notching portion (114) may be formed in the unseen portion (112), and a plurality of foil tabs (113) may be formed by the notching portion (114).

[0073] An insulating coating portion (115) may be disposed at the boundary between the non-retaining portion (112) and the retaining portion (111). The insulating coating portion (115) may be provided, in particular, on the first electrode (11a). The insulating coating portion (115) can prevent the respective retaining portions (111) of the first electrode (11a) and the second electrode (11b) from coming into contact with each other.

[0074]

[0075] FIG. 4 is a flowchart showing the overall process of an electrode manufacturing method according to one embodiment of the present invention, and FIG. 5 is a conceptual diagram showing the overall process of an electrode manufacturing method according to one embodiment of the present invention.

[0076] Hereinafter, with reference to FIGS. 4 and FIGS. 5, a method for manufacturing an electrode according to an embodiment of the present invention will be described in detail. The method for manufacturing an electrode according to an embodiment of the present invention relates to a method for manufacturing an electrode (11), such as a first electrode (11a) and a second electrode (11b), provided in the aforementioned electrode assembly (10). The method for manufacturing an electrode according to an embodiment of the present invention may include steps (a), (b), (c), (d), (e), and (f). Steps (a) through (f) may be performed sequentially.

[0077] (a) Step may be a step in which a camber-preventing member (300) is disposed in a first region (A1) of the electrode sheet (200). The electrode sheet (200) may include a conductive material such as aluminum (Al) or copper (Cu). The electrode sheet (200) may be provided in the form of a rectangular sheet or foil (see FIG. 5 (a)).

[0078] The first region (A1) is a part of the electrode sheet (200) and may be a region where the unpaired portion (210) of the electrode is formed. The first region (A1) may be in a long, extended shape corresponding to the unpaired portion (210) (see FIG. 5 (f)).

[0079] The camber prevention member (300) is a configuration disposed in the first area (A1) and may be provided in a shape corresponding to the first area (A1). The camber prevention member (300) may have a predetermined thickness.

[0080] (b) Step (b) may be a step in which an active material layer (400) is laminated onto an electrode sheet (200). Lamination of the active material layer (400) may be achieved by coating a slurry. The slurry may contain an active material, and such a slurry may be applied to the electrode sheet (200) in a predetermined pattern and a constant thickness, then dried and coated onto the electrode sheet (200), and as the slurry is coated in this way, the active material layer (400) may be laminated onto the electrode (see FIG. 5 (b)).

[0081] The second region (A2) may be an area of ​​the electrode sheet (200) excluding the first region (A1). The second region (A2) may be an area where a retaining portion of the electrode (11) is formed. The slurry may be coated on at least the second region (A2). For example, the slurry may be coated only on the second region (A2), or may be coated on both the second region (A2) and the first region (A1). If the slurry is coated on both the second region (A2) and the first region (A1), the slurry may also be coated on the camber-preventing member (300) placed in step (a).

[0082] (c) Step may be a step in which the electrode sheet (200) having the active material layer (400) laminated thereon is rolled. (c) Step may be a process of passing the electrode sheet (200) having the active material layer (400) laminated thereon between two rolls to flatten the electrode sheet (200). That is, (c) Step may be a roll-pressing process (see FIG. 5 (c)).

[0083] (c) In step, both the first region (A1) and the second region (A2) of the electrode sheet (200) may be stretched. The first region (A1) of the electrode sheet (200) may be stretched by being compressed by the camber prevention member (300), or by the camber prevention member (300) and the active material layer (400). The second region (A2) of the electrode sheet (200) may be stretched by being compressed by the active material layer (400).

[0084] Step (d) may be a step in which the rolled electrode sheet (200) is slit. In step (d), the rolled electrode sheet (200) may be cut to a predetermined design specification using a slitter device (see FIG. 5 (d)).

[0085] (d) In step (d), a drying process to remove remaining moisture from the electrode sheet (200) may be added. The drying process may be carried out as a Roll to Roll Drying process.

[0086] (e) Step may be a step in which the slit electrode sheet (200) is stored. In Step (e), the electrode sheet (200) may be stored with the camber prevention member (300) positioned thereon. The slit electrode sheet (200) may be transferred or transported in the stored state (see FIG. 5 (e)).

[0087] Step (f) is a step in which the camber-preventing member (300) is removed to form a blank portion (210), and then the blank portion (210) is notched. In Step (f), the camber-preventing member (300) may be removed from the electrode sheet (200) immediately before the notching process. That is, the notching process may proceed immediately after the camber-preventing member (300) is removed from the electrode sheet (200). Meanwhile, after Step (f), a winding process of the electrode sheet may proceed (see FIG. 5 (f)).

[0088] In an electrode manufacturing method according to one embodiment of the present invention, a slurry is coated and an active material layer (400) is laminated while a camber prevention member (300) is disposed on an electrode sheet (200), and then the camber prevention member (300) is removed to form an uncoated portion (210). This prevents a sliding phenomenon in which the slurry spreads to a first region (A1) and forms at an angle. Accordingly, the N / P ratio may not decrease or reverse, and the precipitation of lithium (Li) may also be prevented.

[0089] In addition, when the electrode sheet (200) having the active material layer (400) laminated thereon is rolled, the first region (A1) and the second region (A2) of the electrode sheet (200) can both be compressed and stretched. Since the difference between the amount of stretching of the first region (A1) and the amount of stretching of the second region (A2) of the electrode sheet (200) may be relatively small or almost non-existent, the camber phenomenon caused by the difference in the amount of stretching at different positions of the electrode sheet (200) can be effectively prevented.

[0090] Additionally, the slit electrode sheet (200) is stored with the camber prevention member (300) placed thereon, and the camber prevention member (300) can be removed from the electrode sheet (200) immediately before the notching process of the unslit portion (210), so that the camber prevention member (300) can be placed on the electrode sheet (200) for as long as possible. Accordingly, the phenomenon of deepening camber of the electrode sheet (200) due to time, that is, due to the continuation of time, can be effectively suppressed and prevented.

[0091] Accordingly, according to the electrode manufacturing method of one embodiment of the present invention, the quality of the electrode (11) can be improved and the defect rate minimized. In addition, when the battery cell (1) is manufactured by winding the electrode (11), the stability of the battery cell (1) can be improved.

[0092]

[0093] FIG. 6 is a timeline of an electrode manufacturing method according to one embodiment of the present invention.

[0094] Hereinafter, with reference to FIGS. 4 to 6, a method for manufacturing another electrode according to one embodiment of the present invention will be described in more detail.

[0095] (e) step is a step in which the slit electrode sheet (200) is stored for a first time (t1), and (f) step may be carried out for a second time (t2) from the time when step (e) is finished.

[0096] Specifically, with particular reference to FIG. 6, steps (a), (b), (c), and (d) can proceed from an initial time point (T0) (time point) to a first time point (T1).

[0097] (e) Step may be performed during a first time period (t1) from a first time point (T1) to a second time point (T2). That is, the slit electrode sheet (200) after step (d) may be stored during the first time period (t1).

[0098] (f) Step (f) may be performed during a second time period (t2) from a second time point (T2) to a third time point (T3). Here, the second time point (T2) can be understood as the time point at which the camber prevention member (300) begins to be removed from the electrode sheet (200).

[0099] The first time (t1) may be longer than the second time (t2). Specifically, the time during which the slit electrode sheet (200) is stored may be a long period longer than the time during which the unsliced ​​portion (210) is formed on the electrode sheet (200) and the notching process is performed. The first time (t1) may be relatively much longer than the second time (t2). For example, the first time (t1) may be several weeks to several months or more, which is much longer than the second time (t2).

[0100] Meanwhile, the first time (t1) may be longer than the time from the initial time point (T0) to the first time point (T1).

[0101] According to an electrode manufacturing method according to one embodiment of the present invention, even if the slit electrode sheet (200) is stored for a longer period than the time required for forming the unsliced ​​portion (210) and notching, the phenomenon of camber deepening due to the time of the electrode sheet (200) can be effectively prevented by the camber prevention member (300).

[0102]

[0103] FIG. 7 shows the appearance of an electrode sheet after step (a) of an electrode manufacturing method according to one embodiment of the present invention.

[0104] Before explaining, regarding the directions shown in FIG. 7 and the drawings below, the MD direction is the length direction of the electrode sheet (200), the CD direction is the width direction of the electrode sheet (200), and the THD direction is the thickness direction of the electrode sheet (200).

[0105] Hereinafter, with reference to FIG. 4, FIG. 5 (a) and FIG. 7, particularly with reference to FIG. 7, step (a) of the electrode manufacturing method according to one embodiment of the present invention will be described in more detail. FIG. 7 (a) shows a plan view of an electrode sheet (200) viewed in the THD direction, and FIG. 7 (b) shows a cross-sectional view of an electrode sheet (200) viewed in the MD direction.

[0106] As described above, in step (a), a camber prevention member (300) may be disposed on the electrode sheet (200). The camber prevention member (300) may be provided in the form of a strip corresponding to the unoccupied portion (210). That is, the camber prevention member (300) may be provided in a long shape corresponding to the unoccupied portion (210) to be formed in step (f). The camber prevention member (300) may be disposed in the first region (A1).

[0107] The camber prevention member (300) can be attached to the first area (A1). For example, the camber prevention member (300) can be adhered to the first area (A1). The camber prevention member (300) can be provided in a form such as tape.

[0108] When the camber prevention member (300) is provided as described above, the camber prevention member (300) can be easily and accurately attached to the electrode sheet (200), thereby increasing the process efficiency of step (a). Additionally, the camber prevention member (300) can be firmly and stably positioned on the electrode sheet (200).

[0109]

[0110] The camber prevention member (300) may include at least one material selected from polypropylene, polyimide, and polyethylene terephthalate. When the camber prevention member (300) includes such a material, it may have excellent durability, appropriate rigidity, and flexibility.

[0111]

[0112] FIG. 8 shows the appearance of an electrode sheet after step (b) of the electrode manufacturing method according to one embodiment of the present invention.

[0113] Hereinafter, with reference to FIG. 4, FIG. 5 (b) and FIG. 8, particularly with reference to FIG. 8, step (b) of the electrode manufacturing method according to one embodiment of the present invention will be described in more detail. FIG. 8 (a) shows a plan view of an electrode sheet (200) viewed in the THD direction, and FIG. 8 (b) shows a cross-sectional view of an electrode sheet (200) viewed in the MD direction.

[0114] As described above, in step (b), a slurry may be coated on at least a second region (A2) of the electrode sheet (200) to laminate an active material layer (400). In this step (b), the total thickness of the first region (A1) and the total thickness of the second region (A2) may be formed to be approximately the same as each other. Preferably, the total thickness of the first region (A1) and the total thickness of the second region (A2) may be formed to be the same.

[0115] Specifically, the total thickness of the first region (A1) may be formed as the first thickness (TH1). The first thickness (TH1) may be the sum of the thickness of the electrode sheet (200) corresponding to the first region (A1), the total thickness of the camber prevention member (300) disposed in the first region (A1), and the total thickness of the active material layer (400) laminated on the camber prevention member (300).

[0116] The total thickness of the second region (A2) can be formed as the second thickness (TH2). The second thickness (TH2) may be the sum of the thickness of the electrode sheet (200) corresponding to the second region (A2) and the total thickness of the active material layer (400) laminated in the second region (A2).

[0117] These first thickness (TH1) and second thickness (TH2) can be formed approximately the same as each other, or preferably the same. In this case, the difference in thickness at each position in the electrode sheet (200) can be significantly reduced, so that in step (c), both the first region (A1) and the second region (A2) of the electrode sheet (200) can be rolled more effectively.

[0118]

[0119] (b) In step (b), the slurry can be coated on both the second region (A2) of the electrode sheet (200) and the outer surface of the camber prevention member (300). That is, the active material layer (400) can be formed on both the second region (A2) of the electrode sheet (200) and the outer surface of the camber prevention member (300). Here, the outer surface of the camber prevention member (300) can be understood as a surface located on the opposite side of the electrode sheet (200) in the camber prevention member (300).

[0120] When the slurry is coated as described above, the thickness of the active material layer (400) in the second region (A2) of the electrode sheet (200) can be formed uniformly. In particular, the height difference of the active material layer (400) at the boundary between the second region (A2) and the first region (A1) can be effectively and easily suppressed.

[0121]

[0122] FIG. 9 is a cross-sectional view showing the appearance of an electrode sheet after step (b) of an electrode manufacturing method according to a modified example of an embodiment of the present invention.

[0123] Referring to FIG. 9 in comparison with FIG. 8, in step (b) of the electrode manufacturing method according to a modified example of an embodiment of the present invention, the active material layer (400) may be laminated only in the second region (A2) of the electrode sheet (200) and may not be laminated in the first region (A1) of the electrode sheet (200). In this case, the thickness of the camber prevention member (300) and the thickness of the active material layer (400) in the second region (A2) may be the same. In addition, the first thickness (TH1) described above may be the sum of the thickness of the electrode sheet (200) corresponding to the first region (A1) and the total thickness of the camber prevention member (300) placed in the first region (A1).

[0124] According to the electrode manufacturing method according to a modified example of one embodiment of the present invention, the amount of active material layer (400) that is discarded when removing the camber prevention member (300) in step (f) can be reduced.

[0125]

[0126] FIG. 10 shows the appearance of an electrode sheet after step (c) of an electrode manufacturing method according to one embodiment of the present invention.

[0127] Hereinafter, with reference to FIG. 4, FIG. 5 (c) and FIG. 10, particularly with reference to FIG. 10, step (c) of the electrode manufacturing method according to one embodiment of the present invention will be described in more detail. FIG. 10 (a) shows a cross-sectional view of an electrode sheet (200) in a state before rolling as viewed from the MD direction, and FIG. 10 (b) shows a cross-sectional view of an electrode sheet (200) in a state after rolling as viewed from the MD direction.

[0128] As described above, in step (c), the electrode sheet (200) having the active material layer (400) laminated thereon can be rolled. In step (c), the electrode sheet (200) rolled can be formed such that the thickness of the first region (A1) and the thickness of the second region (A2) are the same. That is, the thickness of the electrode sheet (200) corresponding to the first region (A1) in the rolled state and the thickness of the electrode sheet (200) corresponding to the second region (A2) in the rolled state can be formed to be the same.

[0129] Specifically, in the state before rolling, the first region (A1) of the electrode sheet (200) has a third thickness (TH3), and the second region (A2) of the electrode sheet (200) has a fourth thickness (TH4). The third thickness (TH3) and the fourth thickness (TH4) may be the same. And, in the state after rolling, the first region (A1) of the electrode sheet (200) has a third'th thickness (TH3'), and the second region (A2) of the electrode sheet (200) has a fourth'th thickness (TH4'). The third'th thickness (TH3') and the fourth'th thickness (TH4') may be the same.

[0130] As described above, even after rolling through step (c), if the thickness of the first region (A1) and the thickness of the second region (A2) of the electrode sheet (200) are formed to be the same, there is no difference in the amount of elongation caused by rolling between the first region (A1) and the second region (A2) of the electrode sheet (200), so the camber phenomenon of the electrode sheet (200) can be prevented more effectively.

[0131]

[0132] FIG. 11 shows the appearance of an electrode sheet after step (d) of the electrode manufacturing method according to one embodiment of the present invention.

[0133] Hereinafter, with reference to FIG. 4, FIG. 5 (d) and FIG. 11, particularly with reference to FIG. 11, step (d) of the electrode manufacturing method according to one embodiment of the present invention will be described in more detail. FIG. 11 (a) shows a plan view of an electrode sheet (200) viewed in the THD direction, and FIG. 11 (b) shows a cross-sectional view of an electrode sheet (200) viewed in the MD direction.

[0134] As described above, in step (d), the rolled electrode sheet (200) may be slit. Step (d) may include step (d-1). Step (d-1) may be a step in which a first region (A1) of the electrode sheet (200) is slit. A plurality of first regions (A1) may be formed in the electrode sheet (200). For example, as shown in FIG. 11, the first regions (A1) may be formed at the edges and in the center of the electrode sheet (200). The width of the first region (A1) formed in the center may be formed to be larger than the width of the first region (A1) formed at the edges. In step (d-1), the first region (A1) with a relatively larger width as described above may be slit. After step (d-1), a first cut line (SL1) may be formed in the electrode sheet (200).

[0135] As described above, if step (d) includes step (d-1), the number of required camber prevention members (300) can be reduced. Additionally, in step (d-1), the first region (A1) of the electrode sheet (200) is slit with the camber prevention member (300) already placed therein, so unintended damage, such as tearing of the electrode sheet (200), can be effectively prevented during the slitting process.

[0136]

[0137] Meanwhile, step (d) may further include step (d-2). Step (d-2) may be a step in which the second region (A2) of the electrode sheet (200) is slit. That is, in step (d-2), the portion of the electrode sheet (200) where the retaining portion is to be formed may be slit. After step (d-2), a second incision line (SL2) may be formed in the electrode sheet (200).

[0138]

[0139] FIG. 12 shows the electrode sheet being stored in step (e) of the electrode manufacturing method according to one embodiment of the present invention.

[0140] Hereinafter, with reference to FIG. 4, FIG. 5 (e) and FIG. 12, particularly with reference to FIG. 12, step (e) of the electrode manufacturing method according to one embodiment of the present invention will be described in more detail.

[0141] As described above, step (e) may be a step in which the slit electrode sheet (200) is stored. In step (e), the electrode sheet (200) may be stored in a wound state. That is, the electrode sheet (200) may be stored in a so-called pancake state. In this case, not only the storage of the electrode sheet (200) but also transportation or transfer can be carried out easily and efficiently.

[0142] (e) When the electrode sheet (200) is stored in a wound state at step (e), various stresses, such as circumferential stress and radial stress, may be applied to the electrode sheet (200). In this case, the phenomenon of camber deepening of the electrode sheet (200) due to time may occur more severely. However, according to the electrode manufacturing method according to one embodiment of the present invention, the electrode sheet (200) can be stored in a state in which a camber prevention member (300) is placed, so even if the electrode sheet (200) is stored in a wound state as described above, the phenomenon of camber deepening due to time can be effectively prevented.

[0143]

[0144] FIG. 13 shows how an electrode sheet is stored in step (e) of an electrode manufacturing method according to another variation of one embodiment of the present invention.

[0145] Hereinafter, with reference to FIG. 4, FIG. 5 (e) and FIG. 13, particularly with reference to FIG. 13, step (e) of the electrode manufacturing method according to another variation of one embodiment of the present invention will be described in more detail.

[0146] In step (e) of the electrode manufacturing method according to another variation of one embodiment of the present invention, the electrode sheets (200) may be stored in a stacked state in an unfolded state. For example, a plurality of electrode sheets (200) may be stored stacked vertically.

[0147] (e) When the electrode sheets (200) are stacked and stored as described above, the camber prevention member (300) can support the first region (A1), thereby preventing the first region (A1) from sagging in the direction of gravity. Specifically, when electrode sheets (200) are stacked vertically without the camber prevention member (300) placed thereon, the first regions (A1) of the two electrode sheets (200) that are adjacent vertically are spaced apart from each other, so that the first region (A1) of the electrode sheet (200) placed on the upper side can bend in the direction of gravity. However, as in the present invention, when a camber prevention member (300) is disposed in the first region (A1), the camber prevention member (300) of one electrode sheet (200) disposed on the lower side can support the camber prevention member (300) of another electrode sheet (200) disposed on the upper side upward, so that the first region (A1) of the other electrode sheet (200) disposed on the upper side can be effectively prevented from sagging downward.

[0148]

[0149] FIGS. 14 and 15 show the appearance of an electrode sheet after step (f) of an electrode manufacturing method according to one embodiment of the present invention.

[0150] Hereinafter, with reference to FIGS. 4, FIGS. 5 (f), FIGS. 14 and FIGS. 15, particularly with reference to FIGS. 14 and FIGS. 15, step (f) of the electrode manufacturing method according to one embodiment of the present invention will be described in more detail. FIGS. 14 (a) shows a plan view of an electrode sheet (200) viewed in the THD direction, and FIGS. 14 (b) shows a cross-sectional view of an electrode sheet (200) viewed in the MD direction.

[0151] (f) In step (f), the camber prevention member (300) can be removed from the electrode sheet (200) that has been stored after slitting. When the camber prevention member (300) is removed, a blank area (210) in which the active material layer (400) is not laminated can be formed in the first area (A1) of the electrode sheet (200). In step (f), the blank area (210) can be formed on one side of the long side of the electrode sheet (200). For example, as shown in FIG. 14, the blank area (210) can be formed on the left long side of the electrode sheet (200).

[0152] When the camber prevention member (300) is removed from the electrode sheet (200) to form a blank portion (210), the blank portion (210) may be notched, and a plurality of notching tabs (211) may be formed in the blank portion (210). At least one notching portion (212) formed by notching may be formed between two adjacent notching tabs (211). The notching process may be performed immediately after the blank portion (210) is formed on the electrode sheet (200).

[0153]

[0154] FIG. 16 is a cross-sectional view showing the appearance of an electrode sheet after step (c) of an electrode manufacturing method according to another embodiment of the present invention.

[0155] Referring to FIG. 16, in a method for manufacturing an electrode according to another embodiment of the present invention, the camber prevention member (300) may be composed of a plurality of layers. For example, as shown in FIG. 16, a first camber prevention member (310) may be disposed at a position relatively close to the electrode sheet (200), and a second camber prevention member (320) may be disposed laminated on the first camber prevention member (310) at a position relatively far from the electrode sheet (200). Alternatively, the camber prevention member (300) may be composed of three or more layers.

[0156] As described above, when the camber prevention member (300) is composed of multiple layers, the thickness of the camber prevention member (300) can be easily adjusted as needed, and thus there is an advantage in that the thickness of the active material layer (400) of the second region (A2) or the rigidity of the camber prevention member (300) can be easily changed in design.

[0157]

[0158] FIG. 17 is a cross-sectional view showing the appearance of an electrode sheet after step (c) of an electrode manufacturing method according to another embodiment of the present invention.

[0159] Referring to FIG. 17, in an electrode manufacturing method according to another embodiment of the present invention, the camber prevention member (300) is composed of a plurality of layers, as in the electrode manufacturing method according to another embodiment of the present invention, and one layer of the camber prevention member (300) and another layer of the camber prevention member (300) may be provided with different physical properties (e.g., stiffness, flexibility, chemical resistance, and heat resistance). For example, as shown in FIG. 17, a first camber prevention member (310) located relatively close to the electrode sheet (200) and a second camber prevention member (320) located relatively far from the electrode sheet (200) may be provided with different physical properties. These first camber prevention member (310) and second camber prevention member (320) may be provided with different materials or different compositions.

[0160] As described above, when one layer and another layer of the camber prevention member (300) are provided with different physical properties, there is an advantage that the stiffness or flexibility of the camber prevention member (300) can be applied in various ways as needed.

[0161]

[0162] In this specification, terms indicating directions such as up, down, left, right, front, and back have been used; however, these terms are used merely for convenience of explanation, and it is obvious to those skilled in the art that they may vary depending on the location of the object or the position of the observer.

[0163] As described above, although the present invention has been explained by limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs.

[0164] [Explanation of the symbol]

[0165] 1 : Battery cell

[0166] 10 : Electrode assembly

[0167] 11: Electrode

[0168] 11a: First electrode

[0169] 11b : Second electrode

[0170] 12 : Separator

[0171] 20 : Cell Housing

[0172] 30 : Cap

[0173] 40 : 1st tribunal

[0174] 50 : 2nd edition

[0175] 60 : Terminal

[0176] 70: Insulating gasket

[0177] 80: Insulator

[0178] 111 : Maintenance part

[0179] 112 : Mujibu

[0180] 113 : Foil Tab

[0181] 114 : Notching part

[0182] 115 : Insulating coating part

[0183] 200 : Electrode sheet

[0184] 210 : Mujibu

[0185] 211 : Notching tab

[0186] 212 : Notching part

[0187] 300 : Camber prevention member

[0188] 310 : First camber prevention member

[0189] 320 : Second camber prevention member

[0190] 400 : Active material layer

[0191] A1: Area 1

[0192] A2 : Area 2

[0193] SL1: First incision line

[0194] SL2: Second incision line

Claims

1. A method for manufacturing an electrode in which a non-existent portion is extended and formed along the length direction of one long side, wherein (a) A step in which a camber prevention member is disposed in a first region where the above-mentioned blank portion of the electrode sheet is to be formed; (b) A step in which the region excluding the first region in the electrode sheet is a second region, and a slurry is coated on at least the second region of the electrode sheet to laminate an active material layer; (c) a step in which the electrode sheet having the active material layer laminated thereon is rolled so that both the first region and the second region of the electrode sheet are stretched; Step (d) in which the rolled electrode sheet is slit; (e) a step in which the slit electrode sheet is stored; and A method for manufacturing an electrode characterized by including the step (f) in which the camber-preventing member is removed from the electrode sheet to form the blank portion, and then the blank portion is notched.

2. In Paragraph 1, The above step (e) is, The step is for the slit electrode sheet to be stored for a first time period, and The above (f) step is, The above step (e) proceeds for a second time period from the time when the above step (e) is completed, and The above first hour is, A method for manufacturing an electrode characterized by being longer than the second time mentioned above.

3. In Paragraph 1, The above camber prevention member is, It is provided in the form of a strip corresponding to the above-mentioned blank portion, and In step (a) above, A method for manufacturing an electrode characterized in that the above camber prevention member is attached to the first region of the electrode sheet.

4. In Paragraph 3, The above camber prevention member is, A method for manufacturing an electrode characterized by including at least one material selected from polypropylene, polyimide, and polyethylene terephthalate.

5. In Paragraph 1, In step (b) above, A method for manufacturing an electrode characterized in that the total thickness of the first region and the total thickness of the second region are formed to be approximately the same as each other.

6. In Paragraph 1, In step (b) above, A method for manufacturing an electrode characterized by coating the slurry on both the second region of the electrode sheet and the outer surface of the camber prevention member.

7. In Paragraph 1, The electrode sheet rolled in step (c) above is, A method for manufacturing an electrode characterized in that the thickness of the first region and the thickness of the second region are formed to be the same as each other.

8. In Paragraph 1, The above step (d) is, A method for manufacturing an electrode characterized by including a step (d-1) in which the first region of the electrode sheet is slit.

9. In Paragraph 1, In the above step (e), A method for manufacturing an electrode characterized by storing the electrode sheet in a wound state.

10. In Paragraph 1, In the above (e) step, A method for manufacturing an electrode characterized by storing the electrode sheets in a stacked state.

11. In Paragraph 1, The above camber prevention member is, A method for manufacturing an electrode characterized by being composed of multiple layers.

12. In Paragraph 11, The above camber prevention member is, A method for manufacturing an electrode characterized in that one layer of the camber prevention member and another layer of the camber prevention member are provided with different physical properties.

13. An electrode produced by an electrode manufacturing method according to any one of claims 1 to 12.

14. A battery cell comprising at least one electrode according to paragraph 13.

Images