Electrode assembly, battery cell, battery cell processing device, battery pack including the same, and vehicle

Abstract

The electrode assembly includes an electrode cell body part in which a laminate of separators is wound between electrode sheets, and an uncoated part not coated with an active material layer is formed at a widthwise end of the electrode sheet. The electrode cell body part includes a recess part disposed on the core side of the uncoated part and having a height that is recessed in the axial direction more than the uncoated part disposed radially outwardly therefrom. A plurality of cutting lines formed to a predetermined depth in the axial direction are provided at a radially outer portion of the uncoated part than the recess part. The plurality of cutting lines are arranged in a row to form a plurality of cutting line arrays. The cutting line arrays are formed by an ultrasonic vibration cutter part having a blade of a corresponding shape. The bending portion disposed between two adjacent cutting line arrays in the circumferential direction is laid down by pressure by a press part, thereby forming a forming part.

Description

[Technical Field]

[0001] This application claims priority based on Korean Patent Application No. 10-2021-0046800 filed on April 9, 2021, and Korean Patent Application No. 10-2022-0040633 filed on March 31, 2022, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to an electrode assembly, a device for cutting an uncoated portion of the electrode assembly, a folding device, a battery cell including the electrode assembly, and a battery pack and a vehicle including the battery cell. [Background technology]

[0003] In general, secondary batteries contain a positive electrode, a negative electrode, and an electrolyte, and generate electrical energy through a chemical reaction. Secondary batteries, which are easily applicable to a wide range of products and have electrical properties such as high energy density, are widely used not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs), which are powered by electrical sources.

[0004] These secondary batteries have the primary advantage of dramatically reducing the use of fossil fuels and producing no by-products associated with energy consumption. For this reason, secondary batteries are attracting attention as a new energy source that is environmentally friendly and improves energy efficiency.

[0005] Currently, widely used types of secondary batteries include lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel metal hydride batteries, and nickel zinc batteries. The operating voltage of these unit secondary battery cells, i.e., unit battery cells 100, is approximately 2.5V to 4.5V. Therefore, if a higher output voltage is required, a battery pack may be configured by connecting multiple battery cells in series. Alternatively, a battery pack may be configured by connecting multiple battery cells 100 in parallel depending on the required charge / discharge capacity of the battery pack. Therefore, the number of battery cells included in the battery pack and the form of electrical connection can be variously set depending on the required output voltage and / or charge / discharge capacity.

[0006] Meanwhile, known types of unit secondary battery cells include cylindrical, prismatic, and pouch-type battery cells. In the case of a cylindrical battery cell, a separator, which is an insulator, is interposed between a positive electrode and a negative electrode, and the separator is wound up to form a jelly-roll-like electrode assembly. This is then inserted into a battery can to form a battery. Strip-shaped electrode tabs may be connected to the uncoated portions of the positive and negative electrodes. The electrode tabs electrically connect the electrode assembly to electrode terminals exposed to the outside. For reference, the positive electrode terminal is a cap plate of a sealing body that seals the opening of the battery can, and the negative electrode terminal is the battery can. However, conventional cylindrical battery cells with this structure have problems such as high resistance, excessive heat generation, and poor current collection efficiency due to current concentration at the strip-shaped electrode tabs connected to the positive and / or negative uncoated portions. That is, the cross-sectional area of ​​the electrode tabs may be rapidly reduced, causing a bottleneck in current flow.

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

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

[0009] The first and second electrode sheets each have a structure in which an active material is coated on a sheet-shaped current collector, and each includes a non-coating portion on one long side along the winding direction.

[0010] The electrode assembly is fabricated by stacking the first and second electrode sheets together with two separators and then winding them in one direction, with the uncoated portions of the first and second electrode sheets facing in opposite directions.

[0011] After the winding process, the uncoated portions of the first and second electrode sheets are folded toward the core, and then current collecting plates are welded to the uncoated portions.

[0012] The positive and negative uncoated regions do not have separate electrode tabs attached, and the current collecting plates are connected to external electrode terminals, forming a current path with a large cross-sectional area along the winding axis of the electrode assembly, which has the advantage of lowering the resistance of the battery cell, since resistance is inversely proportional to the cross-sectional area of ​​the path through which current flows.

[0013] In a table-less cylindrical battery cell, in order to improve the welding characteristics between the plain portion and the current collecting plate, it is necessary to apply a strong pressure to the welding point of the plain portion and bend the plain portion as flat as possible.

[0014] However, when the welding point of the non-coating portion is bent, the pattern of the non-coating portion may become irregularly distorted and deformed. In this case, the deformed portion may come into contact with the electrode plate of the opposite polarity, causing an internal short circuit or microcracks in the non-coating portion. Furthermore, as the non-coating portion adjacent to the core of the electrode assembly is bent, it may block all or a significant portion of the cavity in the core of the electrode assembly. This causes problems during the electrolyte injection process. That is, the cavity in the core of the electrode assembly serves as a passage through which the electrolyte is injected. However, if this passage is blocked, it is difficult to inject the electrolyte. Furthermore, when the electrolyte injector is inserted into the cavity, it may interfere with the non-coating portion near the core, resulting in tearing of the non-coating portion.

[0015] In addition, the bent portion of the plain area where the current collecting plate is welded must be overlapped in multiple places without any gaps. This ensures sufficient welding strength and prevents the laser from penetrating into the electrode assembly and damaging the separator or active material, even when using cutting-edge technology such as laser welding.

[0016] Korean Patent Publication No. 2022-0023100 (published on March 2, 2022) discloses a cylindrical secondary battery with an improved current collection structure. Cylindrical secondary batteries have a problem in that the current collecting plate is welded to the edge of the uncoated portion in a line contact state, reducing the cross-sectional area of ​​the weld between the current collecting plate and the uncoated portion due to the gap between the uncoated portion. This increases electrical resistance in the weld cross-sectional area, which is the path of current, increasing the amount of heat generated by the battery cell and potentially increasing the risk of fire.

[0017] Korean Patent Publication No. 2016-0110610 (published on September 22, 2016) discloses a secondary battery and a cylindrical lithium secondary battery. These secondary batteries are configured such that a first current collecting plate is electrically connected to a first uncoated portion so that it directly contacts the first uncoated portion, and a second current collecting plate is electrically connected to a second uncoated portion so that it directly contacts the second uncoated portion. This also has the problem that the contact cross-sectional area between the current collecting plate and the uncoated portion is reduced due to gaps between the uncoated portions because the first and second current collecting plates are connected to the ends of the first and second uncoated portions in a line contact state. There is a limit to how much the contact cross-sectional area can be increased. Summary of the Invention [Problem to be solved by the invention]

[0018] The present invention has been devised to solve the above-mentioned problems, and aims to provide an electrode assembly, a battery cell, a battery cell processing device, and a battery pack and vehicle including the same, which can increase the welding cross-sectional area between the electrode assembly and the current collecting plate to expand the current path.

[0019] Another object of the present invention is to provide an electrode assembly, a battery cell, a battery cell processing device, and a battery pack and vehicle including the same, which can suppress an increase in heat generation of a battery cell and reduce the possibility of fire even when the electrode assembly is applied to a large-capacity battery cell.

[0020] Another object of the present invention is to provide an electrode assembly, a battery cell, a battery cell processing device, and a battery pack and a vehicle including the same, which can prevent the boundary between the portion (forming portion) formed by bending the portion to be folded (folding portion) and the portion not to be folded (non-folding portion) from being torn or irregularly distorted and deformed during the folding process of the plain portion.

[0021] Another object of the present invention is to provide an electrode assembly, a battery cell, a battery cell processing device, and a battery pack and vehicle including the same, in which the uncoated portion adjacent to the core of the electrode assembly is folded so as not to block the cavity in the core of the electrode assembly, and the hollow portion of the core is open in the axial direction.

[0022] Another object of the present invention is to provide an electrode assembly, a battery cell, a battery cell processing device, and a battery pack and vehicle including the same, which can reduce the amount of heat generated by the battery cell or significantly reduce the possibility of explosion.

[0023] The technical object of the present invention is not limited to the above-mentioned objects, and other unmentioned objects and advantages of the present invention can be understood from the following description and can be more clearly understood from the embodiments of the present invention. Also, it is clear that the objects and advantages of the present invention can be achieved by the means and combinations thereof set forth in the claims. [Means for solving the problem]

[0024] To solve the above-mentioned problems, the present invention can be applied to an electrode assembly including an electrode cell body part in which first and second electrode sheets having different polarities and a separator for insulation between them are stacked and wound.

[0025] The electrode cell body portion can be wound into a jelly roll.

[0026] The sheets can be stacked in the order of the first electrode sheet, the separator, the second electrode sheet, and the separator.

[0027] The winding may be performed along the length of the stacked sheets, and the axial length of the jelly-roll-shaped electrode cell body portion formed thereby may correspond to the width of the stacked sheets.

[0028] At least one of the first electrode sheet and the second electrode sheet has a plain portion at a widthwise end portion where the active material layer is not coated. Thus, the plain portion is provided at an axial end portion of the electrode cell body portion. The plain portion may be provided on either side of the axial end portion of the electrode cell body portion or on both sides.

[0029] The uncoated portion of the electrode cell body of the electrode assembly is provided with a plurality of cutting lines formed by cutting a portion of the uncoated portion in the axial direction.

[0030] The plurality of cutting lines may be arranged substantially in a line along the radial direction of the electrode cell body portion to form a cutting line array.

[0031] The uncoated portion is divided into a portion to be folded (a portion to be folded) and the other portion (a portion not to be folded) by the cutting line or the cutting line array.

[0032] The forming process may be a bending process.

[0033] The folding process may be a process of laying the plain portion in a radial direction.

[0034] The folding process may be a process of laying the plain portion on the core side.

[0035] The forming portion may be a portion between two adjacent cutting line arrays.

[0036] The forming portion may extend in a radial direction.

[0037] The two adjacent cutting line arrays may be substantially parallel.

[0038] The electrode assembly may include a plurality of forming portions.

[0039] The non-bent portion may be arranged in a fan shape along a circumferential direction with the core portion of the electrode cell body portion as the center.

[0040] The non-bending portion may have a central angle of 30° to 180°. More specifically, the non-bending portion may have a central angle of 45° to 180°, and more preferably, the non-bending portion may have a central angle of 60° to 120°.

[0041] The non-bent portion may be in the form of a plain portion extending in the axial direction without being bent.

[0042] The plurality of forming portions may be arranged radially around a core portion of the electrode cell body portion.

[0043] The forming portion may be formed in a shape in which the intended bending portion is bent and laid in a radial direction of the electrode cell body portion. The intended bending portion may be laid on a core portion side.

[0044] The formed portions may be formed uniformly in the radial direction of the electrode cell body portion.

[0045] The electrode cell body portion may be formed in a cylindrical shape.

[0046] The core portion may be formed in a hollow shape that penetrates through the center of the electrode cell body portion.

[0047] When the intended bending portion is laid down toward the core portion, in order to prevent the core portion from being blocked by the bent intended bending portion, i.e., the forming portion, the uncoated portion disposed closer to the core portion of the core portion and the outer periphery of the electrode assembly can be removed.

[0048] That is, the non-coating portion may be removed from a predetermined section adjacent to the core portion in the winding direction.

[0049] The removal of the uncoated portion can be performed after the electrode stack is manufactured and before the winding process, or alternatively, the removal of the uncoated portion can be performed before the electrode stack is manufactured or after the winding process.

[0050] When the electrode laminate with the core-side uncoated portion removed is wound up, the uncoated portion near the core is already entirely removed along the circumferential direction before the bent portion and non-bent portion are separated along the cutting line. That is, the bent portion is not provided in the core-side uncoated region. Therefore, even when the bent portion is bent toward the core, the laid-down forming portion does not block the core portion of the electrode assembly.

[0051] The present invention provides a battery cell including the electrode assembly.

[0052] The battery cell includes a battery can that houses the electrode assembly, is electrically connected to either the first electrode sheet or the second electrode sheet, and has a first polarity; a sealing cap portion that seals an open end of the battery can; and a first current collecting plate that is electrically connected to the other of the first electrode sheet and the second electrode sheet and has a second polarity.

[0053] The first current collecting plate may be fixed to and electrically connected to a forming portion of the electrode assembly by welding or the like.

[0054] Either the first electrode sheet or the second electrode sheet may be directly connected to the battery can or may be connected to the battery can via a second current collecting plate.

[0055] The battery can may include a supporter portion further protruding radially inward from an inner periphery of the battery can, and the supporter portion may support the sealing cap portion.

[0056] The battery cell may further include an insulator to prevent short circuits of opposite polarities.

[0057] The insulator may be interposed between the battery can and the sealing cap to provide insulation therebetween. More specifically, the insulator may be interposed between the outer circumferential surface of the sealing cap and the inner circumferential surface of the battery can, and may be interposed between the supporter and the sealing cap.

[0058] The insulator may be interposed between the battery can and the first current collecting plate to provide insulation therebetween. For example, the insulator may be interposed between the first current collecting plate and the support portion.

[0059] The present invention provides a battery pack including at least one of the battery cells.

[0060] The present invention provides a vehicle including at least one of the battery packs described above.

[0061] The present invention provides a processing device for cutting and bending the uncoated portion provided at the axial end of the electrode cell body portion of the electrode assembly.

[0062] The processing device provides a cutting device for cutting the non-coating portion.

[0063] The cutting device includes a cutter unit that moves in an axial direction of the electrode assembly to form a cutting line in the uncoated portion in the axial direction.

[0064] The processing device includes a press unit that is disposed between the cutting device and a cutting line array formed by the cutting device and that performs a bending process on the portion to be bent.

[0065] The press unit radially presses and lays the portion of the plain portion to be folded, thereby forming a formed portion.

[0066] The portion to be bent may be pressed in a radial direction, whereby a portion of the portion to be bent corresponding to a lower end of the cutting line may be bent and laid in the radial direction.

[0067] The cutter section may include a plurality of blades arranged radially about the cutter section.

[0068] The blade may extend in the axial direction and have a cutting edge formed at its axial tip.

[0069] The cutter unit may further include a vibration generating unit that generates minute vibrations.

[0070] The pressing unit may move in a radial direction of the electrode cell body unit to lay the portion of the non-coating unit to be folded on the core portion side of the electrode cell body unit.

[0071] The present invention provides a method for manufacturing the above-mentioned battery cell.

[0072] The method for manufacturing such a battery cell includes the steps of laminating a first electrode sheet, a second electrode sheet, and a separator, and winding the laminate to form an electrode assembly.

[0073] Accordingly, the electrode assembly may include an electrode cell body portion in which the electrode sheet and the separator are wound together.

[0074] At least one of the first electrode sheet and the second electrode sheet includes a plain area at either widthwise edge where an active material layer is not applied. The plain area extends along the length of the widthwise edge of the first electrode sheet and / or the second electrode sheet. When both the first electrode sheet and the second electrode sheet have a plain area, the plain area may be provided at each of both widthwise edge portions.

[0075] Accordingly, an uncoated portion may be provided at an axial end of the electrode cell body portion in a protruding form extending in the axial direction.

[0076] In a state where the electrode sheets and the separator are stacked, a portion of the uncoated portion disposed near the core side may be removed by a predetermined length in the longitudinal direction.

[0077] When the electrode stack is wound up with a portion of the uncoated portion located closer to the core side removed, a core-side uncoated region may be provided on the core side of the electrode cell body portion from which a portion of the uncoated portion in the axial direction has been removed. Then, the length by which the uncoated portion in the core-side uncoated region extends axially outward from the electrode cell body portion may be shorter than the length by which the uncoated portion in the uncoated region located radially outward extends axially outward from the electrode cell body portion.

[0078] The removal of the non-coating portion can be carried out after the electrode laminate is formed and before the winding step, and can be carried out by, for example, laser processing.

[0079] The removal of the uncoated portion may be performed at the stage of providing an electrode sheet before constructing the electrode laminate.

[0080] The removal of the non-coating portion can also be carried out after the electrode laminate is wound up to form the electrode cell body portion, and such processing can be carried out, for example, by using a cutter equipped with an ultrasonically vibrating blade.

[0081] The electrode cell body portion may be cylindrical.

[0082] The electrode cell body may include a hollow core.

[0083] The method for manufacturing the battery cell includes forming cutting lines in an axial direction at predetermined positions of the uncoated portions provided at axial ends of the electrode cell body portions.

[0084] Specifically, the step of removing the uncoated portion includes a step of cutting the uncoated portion to a predetermined depth in the axial direction while a cutter moves in the axial direction of the battery cell, thereby forming a cutting line in the uncoated portion in the axial direction.

[0085] The cutting depth may be up to a position at a predetermined distance outward in the axial direction from the boundary between the uncoated portion and the maintained portion, i.e., the cutting line may be formed up to a position at a predetermined distance outward in the axial direction from the boundary between the uncoated portion and the maintained portion.

[0086] A plurality of the cutting lines may be provided, and the cutting line array defined by the plurality of cutting lines may be arranged radially with respect to the electrode cell body portion.

[0087] The method for manufacturing the battery cell may further include forming a forming portion by bending a portion to be bent, which is a portion between a pair of adjacent cutting line arrays, in a radial direction and laying it down.

[0088] The bending process can be performed by pressing the portion to be bent in the radial direction with a press unit.

[0089] The portion where the bending is performed by the bending process may be a portion corresponding to the depth-wise end of the cut line, i.e., a position spaced a certain distance outward in the axial direction at the boundary between the plain portion and the maintained portion.

[0090] The formed portion formed by bending the portion to be bent may be formed radially from a core portion of the electrode cell body portion as a center.

[0091] The forming portion may be formed such that a portion of the non-coating portion to be folded is disposed on a core portion side of the electrode cell body portion.

[0092] The formed portion may be formed along the radial direction of the electrode cell body portion.

[0093] The non-bending portion may be formed by cutting a portion spaced a predetermined distance outward in the axial direction at a boundary between the non-coating portion and the maintaining portion.

[0094] The cutter may be an ultrasonic cutter, and may be configured to cut the non-coating portion while being vibrated by a vibration generating unit.

[0095] A first current collecting plate may be placed on the non-coating portion where the forming portion is formed, and a portion of the first current collecting plate in contact with the forming portion may be welded to the forming portion.

[0096] The present invention provides an electrode assembly manufactured by the above-described processing apparatus and manufacturing method.

[0097] The electrode cell body portion of the electrode assembly is formed by stacking a separator between sheet-shaped first and second electrode sheets, and then winding up the first electrode sheet, the second electrode sheet, and the separator. Uncoated portions that are not coated with the active material layer are formed at widthwise ends of the first and second electrode sheets.

[0098] The electrode assembly may include a recess portion disposed on a core side of the uncoated portion of the electrode cell body portion, the recess portion having a height that is axially recessed greater than that of the uncoated portion disposed radially outward.

[0099] The electrode assembly may include a plurality of cutting lines formed in the uncoated portion of the electrode cell body at a radially outer portion than the recessed portion and extending to a predetermined depth in the axial direction.

[0100] The electrode assembly may include a plurality of cutting line arrays in which the plurality of cutting lines are arranged in a line.

[0101] The electrode assembly may include a plurality of forming portions formed by applying pressure to and laying down portions to be folded in the uncoated portion disposed between two circumferentially adjacent cutting line arrays.

[0102] Two adjacent cutting line arrays may be parallel and extend substantially radially.

[0103] The cutting depth of the cutting line reaches a predetermined portion spaced a predetermined distance outward in the axial direction at the boundary between the non-coating portion and the retained portion.

[0104] The recessed portion may have a height corresponding to the predetermined portion in the axial direction.

[0105] The portion to be bent may be bent at a position corresponding to the predetermined portion in the axial direction.

[0106] The radial width of the recessed portion may correspond to the axial height of the intended bending portion measured from a lower end of the cutting line disposed radially adjacent to the recessed portion. [Effects of the Invention]

[0107] According to the present invention, since the forming portion is welded to the current collecting plate in a state of surface contact, the larger the area of ​​the forming portion, the larger the current path between the electrode assembly and the current collecting plate can be.

[0108] According to the present invention, since the forming portion increases the current path by an area equal to the spacing between the uncoated portions, even when applied to a large-capacity battery cell, the increase in heat generation of the battery cell can be suppressed, thereby reducing the possibility of fire.

[0109] According to the present invention, the thin uncoated portion is cut in the axial direction by the ultrasonic vibration cutter, so that the uncoated portion does not deform and cutting lines can be accurately formed in the uncoated portion.

[0110] According to the present invention, the non-folded portion and the to-be-folded portion of the plain portion are separated from each other in the circumferential direction along the cutting line, and then the to-be-folded portion is pressed and laid down to form the formed portion. This prevents the boundary between the formed portion and the non-folded portion from being torn or deformed irregularly when the to-be-folded portion is pressed to form the formed portion.

[0111] According to the present invention, the boundary between the forming portion and the non-folded portion can be prevented from being torn or deformed, thereby preventing contact with the electrode sheet of the opposite polarity at the torn or deformed portion.

[0112] According to the present invention, a cutting line is formed in an axial direction in a portion of the uncoated portion, and folding of the intended folding portion is guided to occur in a depth direction of the cutting line at a height portion corresponding to the end of the uncoated portion. This prevents the boundary between the uncoated portion and the supporting portion from being torn or deformed when the uncoated portion is folded, thereby preventing the active material coated on the supporting portion from being detached from the supporting portion or weakening of the bonding strength. This prevents a decrease in the performance and capacity of the battery cell.

[0113] According to the present invention, it is possible to prevent the edge of the separator from being lifted or damaged due to a broken or deformed portion at the boundary, thereby preventing a short circuit between the first electrode sheet and the second electrode sheet, and further reducing the amount of heat generated by the battery cell or the possibility of an explosion.

[0114] According to the present invention, the forming portion does not block the hollow core portion of the electrode assembly, which improves the impregnation of the electrolyte and ensures a space that allows welding equipment and the like to enter and exit the hollow portion.

[0115] The above-mentioned effects and specific effects of the present invention will be described in conjunction with the following description of the preferred embodiment of the invention. [Brief explanation of the drawings]

[0116] [Figure 1] 1 is a plan view schematically illustrating an electrode cell stack according to the present invention. [Figure 2] 2 is a cross-sectional view showing the electrode cell stack of FIG. 1 cut in the AA direction. [Figure 3] 2 is a perspective view showing a state in which the electrode cell stack of FIG. 1 is wound up to produce an electrode cell body portion. FIG. [Figure 4] 10 is a perspective view showing a state in which a cutter cuts an electrode cell body according to the present invention. FIG. [Figure 5] FIG. 2 is a perspective view showing a cutter unit according to the present invention. [Figure 6] FIG. 4 is a rear view showing the cutter unit according to the present invention. [Figure 7] 10 is a view of a cutting line array formed in a plain portion of an electrode cell body by a cutter, viewed from an axial direction; [Figure 8] 10 is a view showing a state in which a formed portion is formed by bending a portion to be bent of an electrode cell body portion; [Figure 9] 10 is a view showing a state in which a formed portion is formed by bending a portion to be bent of an electrode cell body portion; [Figure 10] 3 is a flowchart illustrating a method for manufacturing a battery cell according to the present invention. [Figure 11] 1 is a cross-sectional view showing an electrode assembly according to the present invention; [Figure 12] 1 is a perspective view showing a state in which an electrode assembly according to the present invention is housed in a pack housing; [Figure 13] 1 is a perspective view showing a state in which a battery pack according to the present invention is mounted on a vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0117] In the following, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0118] The present invention is not limited to the embodiments disclosed below, but may be embodied in various different forms and with various modifications. However, the present embodiments are provided to fully disclose the present invention and to fully convey the scope of the invention to those skilled in the art. Therefore, the present invention is not limited to the embodiments disclosed below, and should be understood to include all modifications, equivalents, and alternatives within the technical spirit and scope of the present invention, as well as the substitution or addition of the configuration of any embodiment with the configuration of another embodiment.

[0119] The accompanying drawings are intended to facilitate understanding of the embodiments disclosed in this specification, and should not be construed as limiting the technical ideas disclosed in this specification, but should be understood to include any modifications, equivalents, or alternatives that fall within the idea and technical scope of the present invention. The components in the drawings may be exaggerated in size or thickness for ease of understanding, but this should not be interpreted as limiting the scope of protection of the present invention.

[0120] The terms used in this specification are merely used to describe particular embodiments and are not intended to limit the present invention. Furthermore, singular terms include plural terms unless the context clearly dictates otherwise. Terms such as "comprises," "consists," and the like in the specification are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification. In other words, terms such as "comprises," "consists," and the like in the specification should not be understood to preclude the presence or possibility of adding one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0121] Terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by the terms. The terms are used only to distinguish one component from another.

[0122] When a component is referred to as being "coupled" or "connected" to another component, it should be understood that the component may be directly coupled or connected to the other component, but that there may be other components between them. On the other hand, when a component is referred to as being "directly coupled" or "directly connected" to another component, it should be understood that there are no other components between them.

[0123] When a component is referred to as being "on top of" or "under" another component, it should be understood that it may be located not only directly on top of the other component, but that there may be other components in between.

[0124] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms commonly used and similar to dictionary definitions should be interpreted to have a meaning consistent with the meaning they have in the context of the relevant art, and should not be interpreted in an idealized or overly formal sense unless expressly defined in this application.

[0125] Hereinafter, an electrode assembly according to an embodiment of the present invention will be described.

[0126] For ease of explanation, in this specification, the direction along the length of the winding shaft of the electrode assembly 110 wound in a jelly roll shape is referred to as the axial direction (Y). The direction surrounding the winding shaft is referred to as the circumferential direction (X) or peripheral direction. The direction approaching or moving away from the winding shaft is referred to as the radial direction or radial direction (Z). Of these, the direction approaching the winding shaft is particularly referred to as the centripetal direction, and the direction moving away from the winding shaft is particularly referred to as the centrifugal direction.

[0127] 1 to 3, an electrode stack 10 according to an embodiment of the present invention includes a first electrode sheet 11, a second electrode sheet 12, and a separator 13. The electrode stack 10 is formed by laminating the separator 13 between sheet-like first and second electrode sheets 11 and 12. For example, the electrode stack 10 may be formed by laminating one first electrode sheet 11, one second electrode sheet 12, and two separators 13. The electrode stack 10 may also be formed by laminating two or more first electrode sheets 11, two or more second electrode sheets 12, and three or more separators 13. As the number of first electrode sheets 11, second electrode sheets 12, and separators 13 stacked in the electrode stack 10 increases, the winding time and manufacturing time for an electrode assembly 110 with a desired diameter can be shortened.

[0128] The first electrode sheet 11 and the second electrode sheet 12 each include a support portion 14 coated with an active material and an uncoated portion 15 not coated with an active material. The uncoated portion 15 may be formed on one widthwise side of the first electrode sheet 11 and the second electrode sheet 12. At least a portion of the uncoated portion 15 may itself be used as an electrode tab. When the electrode assembly 110 is wound into a cylindrical shape, the uncoated portion 15 of the first electrode sheet 11 may be disposed on one axial side (upper or lower side in FIG. 1), and the uncoated portion 15 of the second electrode sheet 12 may be disposed on the other axial side.

[0129] The uncoated portion 15 of the first electrode sheet 11 and the uncoated portion 15 of the second electrode sheet 12 may be formed to have the same width, or the uncoated portion 15 of the first electrode sheet 11 and the uncoated portion 15 of the second electrode sheet 12 may be formed to have different widths.

[0130] The first electrode sheet 11 may be a negative electrode sheet coated with a negative electrode active material, and the second electrode sheet 12 may be a positive electrode sheet coated with a positive electrode active material. Of course, the first electrode sheet 11 may be a positive electrode sheet coated with a positive electrode active material, and the second electrode sheet 12 may be a negative electrode sheet coated with a negative electrode active material.

[0131] The first electrode sheet 11 and the second electrode sheet 12 each include a current collector made of a metal foil and an active material layer. The metal foil may be aluminum or copper. The active material layer may be coated on one or both sides of the first electrode sheet 11 and the second electrode sheet 12.

[0132] The width of the non-coating portion 15 is significantly narrower than the width of the maintaining portion 14. The non-coating portion 15 may be formed in a narrow band shape. Alternatively, the non-coating portion 15 may be composed of a plurality of sawtooth-shaped segments spaced apart along the length of the non-coating portion 15. The shapes of the segments may be changed to a rectangle, triangle, semicircle, semi-ellipse, parallelogram, etc.

[0133] The non-coating portion 15 may have a removed section (C) near the core side, which can be removed by laser processing or the like after the electrode stack 10 is formed and before winding.

[0134] Of course, the plain portion of the section (C) may be removed in advance when the electrode sheet is provided, or the removed portion 112a of the core-side plain portion may be formed by post-processing after winding.

[0135] In the present invention, the positive electrode active material coated on the first electrode sheet 11 and the negative electrode active material coated on the second electrode sheet 12 may be any active material known in the art without any limitations.

[0136] The positive electrode active material is a layered compound such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; 1+x Mn 2-x Lithium manganese oxides (LiMnO2), such as LiMnO4 (where x is 0 to 0.33), LiMnO3, LiMn2O3, and LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides, such as LiV3O8, LiFe3O4, V2O5, and Cu2V2O7; and the chemical formula LiNi 1-x Mx O2 (where M=Co, Mn, Al, Cu, Fe, Mg, B, or Ga, and x=0.01 to 0.3); 2-x M x The main component may be a lithium intercalation material, such as a lithium manganese composite oxide represented by LiMnO2 (where M=Co, Ni, Fe, Cr, Zn, or Ta, and x=0.01 to 0.1) or Li2Mn3MO8 (where M=Fe, Co, Ni, Cu, or Zn); LiMn2O4, in which part of the lithium in the chemical formula is substituted with an alkaline earth metal ion; a disulfide compound; Fe2(MoO4)3, or a composite oxide formed by a combination of these. Positive electrode active materials include, but are not limited to, the types described above.

[0137] The positive electrode current collector has a thickness of, for example, 3 to 500 μm. There are no particular limitations on the positive electrode current collector, as long as it does not induce chemical changes in the battery and is conductive. For example, the positive electrode current collector can be made of stainless steel, aluminum, nickel, titanium, baked carbon, or aluminum or stainless steel whose surface has been treated with carbon, nickel, titanium, silver, or the like. The electrode current collector can also have fine irregularities formed on its surface to increase the adhesive strength of the positive electrode active material. These electrode current collectors can be in various forms, such as films, sheets, foils, nets, porous bodies, foams, and nonwoven fabrics.

[0138] The positive electrode active material particles may further contain a conductive material. The conductive material may be added in an amount of, for example, 1 to 50 wt % based on the total weight of the mixture containing the positive electrode active material. There are no particular limitations on the conductive material, as long as it does not induce chemical changes in the battery and has high conductivity. Examples of conductive materials that can be used include graphites such as natural graphite and artificial graphite; carbon blacks such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fiber and metal fiber; metal powders such as carbon fluoride, aluminum, and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives.

[0139] The negative electrode sheet is prepared by coating and drying negative electrode active material particles on a negative electrode current collector, and may further contain components such as the aforementioned conductive material, binder, and solvent, as needed.

[0140] The negative electrode current collector has a thickness of, for example, 3 to 500 μm. There are no particular limitations on the negative electrode current collector, so long as it does not induce chemical changes in the battery and is conductive. For example, the negative electrode current collector can be made of copper, stainless steel, aluminum, nickel, titanium, baked carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, or an aluminum-cadmium alloy. Furthermore, as with the positive electrode current collector, fine irregularities can be formed on the surface to strengthen the binding force of the negative electrode active material, and the negative electrode current collector can be used in various forms, such as a film, sheet, foil, net, porous material, foam, or nonwoven fabric.

[0141] The negative electrode active material is, for example, carbon such as non-graphitizable carbon or graphite-based carbon; Li x Fe2O3(0≦x≦1), Li x WO2(0≦x≦1), Sn x Me 1-x Me'yO zMetal composite oxides of (Me: Mn, Fe, Pb, Ge; Me’: Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, halogen; 0 < x ≤ 1; 1 ≤ y ≤ 3; 1 ≤ z ≤ 8); lithium metal; lithium alloy; silicon-based alloy; tin-based alloy; oxides such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, Bi2O5; conductive polymers such as polyacetylene; Li-Co-Ni-based materials, etc. can be used.

[0142] The binder polymer usable in the electrode sheet is a component that helps bind the electrode active material particles with the conductive material and the like and also aids in binding to the electrode current collector, and is added in an amount of, for example, 1 to 50 wt % based on the total weight of the mixture including the electrode active material. Examples of these binder polymers include polyvinylidene fluoride-co-hexafluoropropylene (PVdF), polyvinylidene fluoride-co-trichloroethylene, polymethylmethacrylate, polybutylacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, ethylene-vinyl acetate copolymer (polyethylene-co-vinyl acetate), polyethylene oxide, polyarylate, cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate. The binder polymer may be any one selected from the group consisting of cellulose acetate, cellulose acetate ester ...

[0143] Non-limiting examples of solvents that can be used in the manufacture of the electrode include acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (NMP), cyclohexane, water, or mixtures thereof. These solvents provide an appropriate level of viscosity so that a slurry coating layer can be formed at a desired level on the surface of the electrode current collector.

[0144] The separator 13 includes a porous polymer substrate and porous coating layers disposed on both sides of the porous polymer substrate, the coating layers including inorganic particles and a binder polymer.

[0145] The porous polymer substrate may be a polyolefin-based porous substrate.

[0146] The polyolefin porous substrate may be in the form of a film or a non-woven web. The porous structure facilitates smooth electrolyte transfer between the positive and negative electrodes. The porous structure also increases the electrolyte impregnation of the substrate itself, ensuring excellent ionic conductivity and preventing an increase in the internal resistance of the electrochemical device, thereby preventing performance degradation of the electrochemical device.

[0147] The polyolefin porous substrate used in the present invention can be any planar porous substrate typically used in electrochemical elements, and its material and shape can be selected in a variety of ways depending on the intended purpose.

[0148] The polyolefin porous substrate may be, but is not limited to, a film or nonwoven web formed from high density polyethylene, low density polyethylene, linear low density polyethylene, ultra-high molecular weight polyethylene, polypropylene, or a mixture of two or more of these.

[0149] The polyolefin porous substrate may have a thickness of 8 to 30 μm, but this is merely an example, and thicknesses outside the above range may be adopted in consideration of mechanical properties and efficient charge / discharge characteristics of the battery.

[0150] The separator 13 according to the present invention may have a thickness of 1 to 100 μm or 5 to 50 μm. If the thickness of the separator 13 is less than 1 μm, the separator 13 may not function sufficiently and mechanical properties may deteriorate. If the thickness of the separator 13 is more than 100 μm, battery properties may deteriorate during high-rate charge / discharge. In addition, the separator 13 may have a porosity of 40 to 60% and an air permeability of 150 to 300 seconds / 100 mL.

[0151] When using a separator 13 according to an embodiment of the present invention, porous coating layers are provided on both sides of a porous polymer substrate, which improves the electrolyte impregnation performance and allows the formation of a uniform solid electrolyte interfacial layer, thereby ensuring superior air permeability compared to conventional cross-section inorganic-coated separators 13. For example, the air permeability may be within 120 s / 100 cc. Furthermore, even when inorganic porous coating layers are provided on both sides, the thickness can be the same as that of conventional cross-section inorganic-coated separators 13. For example, the thickness may be within 15.0 μm.

[0152] Furthermore, when the separator 13 according to an embodiment of the present invention is used, the stability of the separator 13 is improved, and heat resistance and pressure resistance properties can be ensured. Specifically, heat resistance properties such as thermal shrinkage of 5% or less at 180°C can be ensured, and a puncture strength of 550 gf or more can be ensured. When core deformation occurs during the cycle of a battery using such a separator 13, damage or puncture of the separator 13 at the step portion can be prevented.

[0153] An electrode assembly manufactured using the above-described electrode laminate will now be described.

[0154] 4 to 9, the electrode assembly 110 includes an electrode cell body portion 111, a plurality of non-bent portions 115a, and a plurality of formed portions 117.

[0155] The electrode cell body 111 is a cylindrical portion wound up in a jelly roll shape with the separator 13 laminated between the sheet-like first electrode sheet 11 and second electrode sheet 12. As described above, the uncoated portions 15, which are not coated with an active material layer, are formed at the widthwise ends of the first electrode sheet 11 and the second electrode sheet 12, and these are disposed on one and the other axial sides of the electrode cell body 111, respectively, and extend in the axial direction.

[0156] The electrode cell body 111 can be formed by winding the electrode stack, which is elongated in the longitudinal direction, around a winding rod (not shown) and then removing the winding rod from the electrode cell body 111. In this case, the more first electrode sheets 11, second electrode sheets 12, and separators 13 are stacked on the electrode stack 10, the shorter the winding time and manufacturing time for the electrode assembly 110 can be. The area where the winding rod is removed from the electrode cell body 111 forms a hollow core 112.

[0157] On one axial side of the electrode cell body portion 111, the uncoated portion 15 of the first electrode sheet 11 is exposed to a certain height, and on the other axial side of the electrode cell body portion 111, the uncoated portion 15 of the second electrode sheet 12 is exposed to a certain height.

[0158] Furthermore, due to the removal portion (C) of the non-coating portion, a recessed portion 112a is provided in the non-coating portion section adjacent to the core portion 112.

[0159] The cutter unit 210 cuts the uncoated portion 15 of the electrode cell body portion 111 in the axial direction. As a result, a cutting line 113 is formed between the non-bending portion 115a and the to-be-bended portion 117a. The cutting line 113 circumferentially separates the non-bending portion 115a from the to-be-bended portion 117a. That is, the cutting line 113 separates the non-bending portion 115a from the to-be-bended portion 117a. The cutting line 113 extends in the axial direction from the axial end of the uncoated portion 15 toward the electrode cell body portion 111. At this time, the non-bending portion 115a and the to-be-bended portion 117a maintain their standing state along the axial direction of the electrode cell body portion 111.

[0160] As a result, the uncoated portion 15 of the electrode cell body portion 111 is provided with a non-bending portion 115a and a portion to be bent 117a.

[0161] The cutter unit 210 for cutting the cutting line 113 may be an ultrasonic cutter to prevent buckling that may occur when cutting a thin plain portion in the axial direction.

[0162] The cutter unit 210 includes a plurality of blades 211 arranged in a direction corresponding to the radial direction of the electrode cell body unit 111, and a vibration generating unit 213 to which the blades 211 are fixed.

[0163] The vibration generating unit 213 includes a circular plate and a vibration source for vibrating the circular plate.

[0164] The plurality of blades 211 may have their base ends fixed to the surface of the circular plate of the vibration generating unit 213, extend in a direction corresponding to the axial direction of the electrode cell body unit 111, and have sharp blades at their tips.

[0165] The blades 211 are arranged radially with respect to the center of the vibration generating unit 213. For example, a pair of blades 211 defining the intended bending portion 117a may be formed at four locations in a cross shape with respect to the center of the vibration generating unit 213. Alternatively, the pair of blades 211 may be arranged radially at six locations at 60° intervals. Alternatively, the pair of second blades 221 may be arranged radially at three locations at 120° intervals. The angle between the pair of blades 211 can be appropriately selected depending on the diameter of the electrode cell body portion 111, the capacity of the battery pack, and the shape of the current collecting plate to be welded thereto.

[0166] In the embodiment, a preferred structure is exemplified in which the pair of blades 211 defining the intended bending portion 117a are arranged parallel to each other in a straight line. However, the pair of first blades 211 do not necessarily need to be arranged strictly parallel. For example, the pair of blades 211 may be configured so that the distance between them gradually increases toward the centrifugal direction, or the distance between them gradually increases toward the centripetal direction. Furthermore, although the blades 211 are exemplified as being linear, the blades 211 do not necessarily need to be linear. For example, the blades 211 may be gently curved.

[0167] The circumferential distance between one pair of blades 211 and another adjacent pair of blades 211 becomes closer in the centripetal direction and becomes farther away in the centrifugal direction, which defines the fan shape of the non-bending portion 115a.

[0168] The vibration generating unit 213 may include an ultrasonic vibrator. A first communication hole 215 is formed in the center of the vibration generating unit 213 to communicate with the core unit. The vibration generating unit 213 generates ultrasonic vibrations when the blade 211 moves in the axial direction of the electrode cell body unit 111 and cuts the uncoated portion 15.

[0169] If the force of blade 211 pressing uncoated portion 15 in the axial direction is not used to process cutting line 113 and uncoated portion 15 is pressed, there is a possibility that uncoated portion 15 may buckle or the portion of uncoated portion 15 near cutting line 113 may be warped or broken, or other deformation may occur.

[0170] On the other hand, when the blade 211 is ultrasonically vibrated, the above-mentioned phenomenon is prevented when the blade 211 cuts the non-coated portion 15, and the cutting process is carried out very smoothly. This improves the cutting speed of the non-coated portion 15 and allows the cutting line 113 of the non-coated portion 15 to be formed smoothly. Various vibration methods can be used for the vibration generating unit 213 as long as it vibrates the blade 211.

[0171] The plurality of non-bending portions 115a may be arranged at equal intervals along the circumferential direction around the core portion 112. Furthermore, the plurality of non-bending portions 115a may be formed to have the same size and the same shape.

[0172] A recess 112a is formed between the uncoated portion 15 and the core portion 112 on one or both axial sides of the electrode cell body portion 111. The recess 112a is formed concentrically with the core portion 112. The recess 112a is formed in an annular shape so as to surround the core portion 112.

[0173] The height of the upper end of the recessed portion 112a may substantially correspond to the height of the lower end of the cutting line 113. The radial width of the recessed portion 112a may be the same as, slightly wider than, or narrower than the axial height of the uncoated portion 15 measured from the lower end of the cutting line 113.

[0174] The multiple formed portions 117 are formed by pressing and laying the planned folding portions 117a of the uncoated portion 15 arranged between the non-folded portions 115a in a direction intersecting the axial direction, for example, in the radial direction. The multiple formed portions 117 may be formed by pressing and laying the planned folding portions 117a of the uncoated portion 15 using a press unit 230 described below. In this case, the multiple formed portions 117 may be laid with multiple uncut pieces forming the planned folding portions 117a continuously overlapping each other. As a result, the formed portions 117 may be formed at an angle with respect to the axial direction of the electrode cell body portion 111, or may be completely laid down and formed flat.

[0175] The plurality of forming portions 117 are welded to the current collecting plates 130 and 140 to form current paths. Furthermore, the plurality of non-bent portions 115a may also be electrically connected to the current collecting plates 130 and 140 by contacting or welding them. However, because the non-bent portions 115a are welded (e.g., laser welded) to the current collecting plates 130 and 140 while in line contact with the current collecting plates 130 and 140, the non-bent portions 115a do not have as great an effect of increasing the current paths as compared with the forming portions 117. On the other hand, because the forming portions 117 are formed by laying the to-be-bent portions 117a in the radial direction, the forming portions 117 cover the gaps between the uncoated portions 15 spaced apart by the thickness of the separator 13. These forming portions 117 are welded to the current collecting plates 130 and 140 in surface contact, and therefore the larger the area of ​​the forming portions 117, the greater the relative increase in the current path between the electrode assembly 110 and the current collecting plates 130 and 140. These forming portions 117 increase the current path by the combined area of ​​the gaps between the uncoated portions 15, and therefore, even when applied to a large-capacity battery cell 100, an increase in the amount of heat generated by the battery cell 100 can be suppressed, thereby reducing the possibility of fire.

[0176] If the unbent portion 115a is exposed and not welded to the current collecting plates 130 and 140, the impregnation of the electrolyte may be improved when the electrolyte is injected into the electrode assembly. Although the impregnation of the electrolyte may be weakened in the area of ​​the forming portion 117 due to the bending of the uncut piece, the cut surface 115a, which is adjacent to the forming portion 117, compensates for this, so there is no particular problem with the impregnation of the electrolyte.

[0177] According to the present invention, the non-folded portion 115a and the to-be-folded portion 117a in the uncoated portion 15 are circumferentially separated from each other by a cutter that forms a cutting line in the axial direction, and then the to-be-folded portion 117a is pressed and laid down to form the formed portion 117. This prevents the boundary portion 16 between the formed portion 117 and the non-folded portion 115a from being torn or deformed irregularly when the to-be-folded portion 117a is pressed to form the formed portion 117.

[0178] Furthermore, since the boundary 16 between the forming portion 117 and the non-bending portion 115a can be prevented from being torn or deformed, contact with the electrode sheets 11 and 12 of opposite polarity at the torn or deformed portion can be prevented. Furthermore, since the boundary 16 between the non-coating portion 15 and the maintaining portion 14 can be prevented from being torn or deformed, the active material coated on the maintaining portion 14 can be prevented from being detached from the maintaining portion 14 or the bonding strength can be prevented from being weakened. As a result, a decrease in the performance and capacity of the battery cell 100 can be suppressed.

[0179] In addition, the edge of the separator 13 can be prevented from being lifted or damaged due to a torn or deformed portion of the boundary portion 16. This can prevent a short circuit between the first electrode sheet 11 and the second electrode sheet 12. Furthermore, the amount of heat generated by the battery cell 100 can be reduced, and the possibility of an explosion can be significantly reduced.

[0180] In addition, since the forming portion 117 is formed by compressing the bending portion 117a while the non-bending portions 115a on both sides of the bending portion 117a are circumferentially separated, the uncut pieces of the bending portion 117a can be prevented from tilting and opening due to a spring back phenomenon. Furthermore, when the bending portion 117a is compressed with a strong pressure using the press unit 230, the forming portion 117 (the uncut pieces of the bending portion 117a) can be superimposed on the non-bending portion 115a in a state of being as flat and tightly attached as possible. As a result, the forming portion 117 and the cut portions are welded to the current collecting plates 130 and 140 in surface contact, thereby significantly increasing the weld cross-sectional area. Furthermore, an increase in the weld cross-sectional area increases the cross-sectional area of ​​the current path, which advantageously significantly reduces the resistance of the battery cell 100. This is because resistance is inversely proportional to the cross-sectional area of ​​the path through which current flows.

[0181] The non-bending portion 115a is formed in a fan shape along the circumferential direction, centered on the core portion 112 of the electrode cell body portion 111. The apex of the non-bending portion 115a faces the core portion 112. Because the non-bending portion 115a is formed in a fan shape, each forming portion 117 may be arranged radially between the multiple non-bending portions 115a, centered on the core portion 112. Furthermore, the outer width of the forming portion 117 may be the same as or wider than the width of the core portion 112 along the central angle of the fan-shaped non-bending portion 115a.

[0182] Preferably, the non-bending portions 115a may have a central angle (θ1: see FIG. 7) of 60° to 120°. The central angle (θ1) is the angle between the vertex of the sector and the opening of both sides. When the central angle (θ1) of the non-bending portions 115a is 90°, four non-bending portions 115a may be formed in a cross shape in the circumferential direction of the non-coated portion 15. When the central angle (θ1) of the non-bending portions 115a is 60°, six cut surfaces may be formed in the circumferential direction of the non-coated portion 15. When the central angle (θ1) of the non-bending portions 115a is 120°, three cut surfaces may be formed in the circumferential direction of the non-coated portion 15. In the present invention, the central angle of the non-bending portions is not limited to the above range. For example, the central angle may be 45°, 30°, or 180°.

[0183] The intended folding portion 117a is folded at a portion spaced a certain distance outward in the axial direction from the boundary portion 16 between the non-coated portion 15 and the maintaining portion 14. This portion corresponds to the height corresponding to the end of the cutting line 113. As a result, when the intended folding portion 117a is folded, the non-coated portion 15 is folded at a position spaced apart from the maintaining portion 14. This prevents deformation of the non-coated portion due to folding from being transmitted to the maintaining portion, thereby preventing detachment of the active material coated on the maintaining portion 14.

[0184] The central angle of the non-bending portion 115a can be appropriately selected taking into consideration the diameter of the electrode cell body portion 111, the capacity of the battery cell 100, and the like. For example, the larger the diameter of the electrode cell body portion 111, the closer the central angle of the non-bending portion 115a can be formed to 60°. This is because, as the diameter of the electrode cell body portion 111 increases, the enlargement of the cross-sectional area of ​​the current path is advantageous for preventing heat generation and fire, and the central angle of the non-bending portion 115a is reduced to increase the area of ​​the forming portion 117. Furthermore, the larger the capacity of the electrode cell body portion 111, the closer the central angle of the non-bending portion 115a can be formed to 60°.

[0185] The forming portions 117 may be formed radially around the core portion 112 of the electrode cell body portion 111. When four forming portions 117 are formed in a cross shape, the central angle of the non-bent portions 115a is 90°. When six forming portions 117 are formed radially around the core portion 112, the central angle of the non-bent portions 115a is 60°. When three forming portions 117 are formed radially around the core portion 112, the central angle of the non-bent portions 115a is 120°. Because the forming portions 117 are formed radially around the core portion 112, the current paths are uniformly dispersed in the circumferential direction of the electrode cell body portion 111.

[0186] The forming portion 117 may be formed in a shape in which the intended folding portion 117a of the non-coating portion 15 lies on the core portion 112 side of the electrode cell body portion 111. This prevents the forming portion 117 from protruding outward from the outer circumferential surface of the electrode cell body portion 111, so that the electrode assembly 110 can be smoothly inserted into the battery can 120 during manufacturing of the battery cell 100. In addition, the forming portion 117 can be prevented from hanging over the battery can 120.

[0187] When the bent portion 117a is placed on the core portion 112 side of the electrode cell body portion 111, the bent portion 117a adjacent to the core portion 112 may block the core portion 112 when placed thereon.

[0188] The core portion 112 can serve as a passage for introducing an electrolyte or, in some cases, a passage for inserting a welding rod. In this regard, it is preferable that the core portion 112 be open in the axial direction. Therefore, if a section (C) of the uncoated portion located on the core side is pre-cut as shown in FIG. 1(b), and then the electrode assembly is fabricated as described above, the uncoated portion adjacent to the core portion 112 is removed as shown in FIGS. 3 and 4. If the forming portion 117 is formed in this state, the core portion 112 is not obstructed as shown in FIGS. 8 and 9.

[0189] The forming portions 117 may be formed uniformly in the radial direction of the electrode cell body portion 111. The forming portions 117 may be formed symmetrically with respect to the core portion 112 of the electrode cell body portion 111. This allows the forming portions 117 to form current paths of almost the same area in the radial direction of the electrode cell body portion 111.

[0190] A core portion 112 may be formed at the center of the electrode cell body portion 111. The core portion 112 is formed to have a hollow shape that penetrates the center of the electrode cell body portion 111. The cross section of the core portion 112 may be circular. Because the core portion 112 is formed to have a hollow shape, an electrolyte injector (not shown) can inject electrolyte through the core portion 112 after the electrode assembly 110 is placed in the battery can 120. This reduces the time required to inject the electrolyte, thereby reducing the time required to manufacture the battery cell 100. In addition, when the electrolyte injector is inserted into the core portion 112, the electrode sheets 11 and 12 and the separator 13 near the core portion 112 can be prevented from being caught and torn or damaged.

[0191] The electrode cell body portion 111 may be formed in a cylindrical shape, which allows the electrode cell body portion 111 to be inserted into the cylindrical battery can 120 so that the outer surface of the electrode cell body portion 111 is in close contact with the inner surface of the cylindrical battery can 120.

[0192] Next, a method for manufacturing a battery cell according to the present invention will be described with reference to FIG.

[0193] A separator 13 is laminated between sheet-like first and second electrode sheets 11 and 12 (S11). At this time, the structure in which the first electrode sheet 11, the second electrode sheet 12, and the separator 13 are laminated is called an electrode stack 10. In the electrode stack 10, the uncoated portion 15 of the first electrode sheet 11 protrudes to one widthwise side of the electrode stack 10, and the uncoated portion 15 of the second electrode sheet 12 protrudes to the other widthwise side of the electrode stack 10.

[0194] The first electrode sheet 11, the second electrode sheet 12, and the separator 13 are wound into a jelly roll shape (S12). At this time, the electrode stack 10 is wound around a winding rod to form an electrode assembly 110, and the winding rod is separated from the electrode assembly 110. A hollow core portion 112 is formed in the center of the electrode assembly 110, where the winding rod has been removed. The core portion 112 is formed to penetrate the electrode assembly 110 in the axial direction. The more first electrode sheets 11, second electrode sheets 12, and separators 13 are stacked on the electrode stack 10, the shorter the winding time and manufacturing time for the electrode assembly 110 can be.

[0195] The removal of the partial region (C) of the uncoated portion shown in Fig. 1(b) can be carried out after the electrode stacking step (S11) and before the winding step (S12). This may be a process in which the partial region of the uncoated portion is cut and removed by laser cutting.

[0196] The depth to which the non-coating portion 15 in the predetermined section (C) is removed and the depth of the cutting line 113 may correspond to each other.

[0197] The cutter unit 210 cuts radially the uncoated portions 15 of the first electrode sheet 11 and the second electrode sheet 12 while moving in the axial direction of the battery cell 100 (S13). At this time, the cutter unit 210 cuts the uncoated portion 15 of the electrode cell body portion 111 in the axial direction to separate the non-bending portion 115a and the portion to be bent 117a in the circumferential direction. At this time, the non-bending portion 115a and the portion to be bent 117a maintain a standing state along the axial direction of the electrode cell body portion 111.

[0198] The press unit 230 applies pressure to the bent portions 117a of the non-coated portion 15 and lays them down, thereby forming the formed portion 117 (S14). The multiple formed portions 117 are arranged between the non-bent portions 115a and are formed by applying pressure to the bent portions 117a of the non-coated portion 15 and laying them down. The multiple formed portions 117 may be formed by applying pressure to the bent portions 117a of the non-coated portion 15 and laying them down using the press unit 230 described below. In this case, the multiple formed portions 117 may be laid down with multiple uncut pieces constituting the bent portions 117a continuously overlapping each other. As a result, the formed portion 117 may be formed slightly inclined in the axial direction of the electrode cell body portion 111 or may be formed flat.

[0199] The formed portion 117 may be formed by bending the lower end of the portion to be bent 117 a corresponding to the cutting depth of the cutting line 113 .

[0200] The non-bending portions 115a are laser-welded to the current collecting plates 130, 140 in line contact with the current collecting plates 130, 140, which increases the current path. Meanwhile, the forming portions 117 are formed by radially extending the intended bending portions 117a, so that the forming portions 117 cover the gaps between the uncoated portions 15 spaced apart by the thickness of the separator 13. Because the forming portions 117 are welded to the current collecting plates 130, 140 in surface contact, the larger the area of ​​the forming portions 117, the greater the increase in the current path between the electrode assembly 110 and the current collecting plates 130, 140. Because the forming portions 117 increase the current path by the area including the gaps between the uncoated portions 15, even when applied to a large-capacity battery cell 100, the increase in heat generation from the battery cell 100 can be suppressed, reducing the risk of fire.

[0201] In the manufacturing method of the present invention, after the non-folded portion 115a and the to-be-folded portion 117a in the plain portion 15 are separated from each other, the to-be-folded portion 117a is pressed and laid down to form the formed portion 117. This prevents the boundary portion 16 between the to-be-folded portion 117 and the non-folded portion 115a from being torn or deformed irregularly when the to-be-folded portion 117a is pressed to form the formed portion 117.

[0202] In addition, the edge of the separator 13 can be prevented from being lifted or damaged due to a torn or deformed portion of the boundary portion 16. This can prevent a short circuit between the first electrode sheet 11 and the second electrode sheet 12. Furthermore, the amount of heat generated by the battery cell 100 can be reduced, and the possibility of an explosion can be significantly reduced.

[0203] The non-bending portions 115a may be formed in a fan shape along the circumferential direction with the core portion 112 of the electrode cell body portion 111 at the center. The apex of the non-bending portion 115a faces the core portion 112. Because the non-bending portions 115a are formed in a fan shape, each forming portion 117 may be arranged radially between the multiple non-bending portions 115a with the core portion 112 at the center.

[0204] The non-bent portions 115a may have a central angle (θ1) of 60° to 120°. For example, if the central angle (θ1) of the non-bent portions 115a is 90°, four non-bent portions 115a may be formed in a cross shape in the circumferential direction of the uncoated portion 15. If the central angle (θ1) of the non-bent portions 115a is 60°, six cut surfaces may be formed in the circumferential direction of the uncoated portion 15. If the central angle (θ1) of the non-bent portions 115a is 120°, three cut surfaces may be formed in the circumferential direction of the uncoated portion 15.

[0205] The intended folding portion 117a is folded at a portion spaced a certain distance outward in the axial direction from the boundary portion 16 between the non-coated portion 15 and the maintaining portion 14. This portion corresponds to the height corresponding to the end of the cutting line 113. As a result, when the intended folding portion 117a is folded, the non-coated portion 15 is folded at a position spaced apart from the maintaining portion 14. This prevents deformation of the non-coated portion due to folding from being transmitted to the maintaining portion, thereby preventing detachment of the active material coated on the maintaining portion 14.

[0206] The forming portions 117 may be formed radially around the core portion 112 of the electrode cell body portion 111. When four forming portions 117 are formed in a cross shape, the central angle (θ1) of the non-bent portions 115a is 90°. When six forming portions 117 are formed radially around the core portion 112, the central angle (θ1) of the non-bent portions 115a is 60°. When three forming portions 117 are formed radially around the core portion 112, the central angle (θ1) of the non-bent portions 115a is 120°. Because the forming portions 117 are formed radially around the core portion 112, the current paths can be uniformly dispersed in the circumferential direction of the electrode cell body portion 111.

[0207] The forming portion 117 may be formed in a shape in which the intended folding portion 117a of the non-coating portion 15 lies on the core portion 112 side of the electrode cell body portion 111. This prevents the forming portion 117 from protruding outward from the outer circumferential surface of the electrode cell body portion 111, so that the electrode assembly 110 can be smoothly inserted into the battery can 120 when manufacturing the battery cell 100. In addition, the forming portion 117 can be prevented from hanging over the battery can 120.

[0208] The formed portion 117 may be formed along the radial direction of the electrode cell body portion 111. The formed portion 117 may be formed symmetrically with the core portion 112 of the electrode cell body portion 111 as the center.

[0209] The cutter unit 210 cuts the uncoated portion 15 while vibrating due to the vibration generating unit 213. The vibration generating unit 213 may include an ultrasonic vibrator. Since the cutter unit 210 cuts the uncoated portion 15 while vibrating, the cutting performance and cutting speed of the uncoated portion 15 can be improved.

[0210] A battery cell manufactured using the above electrode assembly will now be described.

[0211] Referring to FIG. 11, a battery cell 100 according to the present invention includes an electrode assembly 110, a battery can 120, a sealing cap portion 150, and a first current collecting plate .

[0212] The electrode assembly 110 is substantially the same as that described above, and therefore, a description thereof will be omitted.

[0213] The electrode assembly 110 is accommodated inside the battery can 120. The battery can 120 is electrically connected to either the first electrode sheet 11 or the second electrode sheet 12 and has a first polarity. The battery can 120 may be made of a conductive material to allow current to flow. For example, the battery can 120 may be made of a material including stainless steel, aluminum, etc. The battery can 120 may be formed in a cylindrical shape with an open end on one side.

[0214] The sealing cap 150 seals the open end of the battery can 120. The sealing cap 150 is installed to be insulated from the battery can 120. The sealing cap 150 prevents external foreign matter and moisture from penetrating into the battery can 120.

[0215] The first current collecting plate 130 has a second polarity and is electrically connected to the other of the first electrode sheet 11 and the second electrode sheet 12. The first current collecting plate 130 may be disposed between the electrode assembly 110 and the sealing cap portion 150. The first current collecting plate 130 is electrically connected to the sealing cap portion 150. The first current collecting plate 130 may be welded to the uncoated portion 15 of the other of the first electrode sheet 11 and the second electrode sheet 12. In this case, the formed portion 117 of the uncoated portion 15 may be welded to the first current collecting plate 130 in line contact, and the non-bent portion 115a of the uncoated portion 15 may be welded to the first current collecting plate 130 in line contact. This increases the weld cross-sectional area between the uncoated portion 15 and the first current collecting plate 130, thereby increasing the cross-sectional area of ​​the current path and significantly reducing the electrical resistance of the battery cell 100. Furthermore, the amount of heat generated by the battery cell 100 can be reduced, making it possible to lower the possibility of the battery cell 100 catching fire.

[0216] The first electrode sheet 11 may be a negative electrode sheet and the second electrode sheet 12 may be a positive electrode sheet. Alternatively, the first electrode sheet 11 may be a positive electrode sheet and the second electrode sheet 12 may be a negative electrode sheet.

[0217] An electrolyte solution is poured into the battery can 120 through the core portion 112 of the electrode assembly 110 .

[0218] The electrolyte is A + B - The salt may have the following structure: + Li + , Na + , K. + These include alkali metal cations such as B and B - is F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , AlO4- , AlCl4 - , PF6 - , SbF6 - , AsF6 - , BF2C2O4 - , BC4O8 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , C4F9SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - , and (CF3CF2SO2)2N - The anion comprises at least one anion selected from the group consisting of:

[0219] The electrolyte may also be dissolved in an organic solvent, such as propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethyl methyl carbonate (EMC), gamma-butyrolactone, or a mixture thereof.

[0220] The sealing cap part 150 may further include an insulator 157 that covers the first current collecting plate 130 and has an edge interposed between the inner circumferential surface of the support part 122 and the first current collecting plate 130. The insulator 157 electrically insulates the sealing cap part 150 from the battery can 120.

[0221] The insulator 157 may be made of an insulating polymer resin, such as polyethylene, polypropylene, polyimide, or polybutylene terephthalate.

[0222] The sealing cap portion 150 includes a cap plate 151 attached to close the open end of the battery can 120. The cap plate 151 may be formed in a disk shape as a whole. An external terminal 152 is formed at the center of the cap plate 151 so as to protrude outward (toward the upper side in FIG. 13).

[0223] The sealing cap part 150 includes a vent plate 153 disposed under the cap plate 151. The vent plate 153 breaks when the internal pressure of the battery can 120 exceeds a predetermined pressure. The vent plate 153 prevents the battery cell 100 from exploding.

[0224] The bent plate 153 and the first current collecting plate 130 are electrically connected by a lead portion 155. The bent plate 153 also contacts the cap plate 151 to form a part of a current path.

[0225] A supporter part 122 is formed below the open end of the battery can 120, and is recessed into the inside of the battery can 120. A vent plate 153 and a cap plate 151 are stacked above the supporter part 122.

[0226] Insulators 157 are interposed between the inner surface of the supporter portion 122, the vent plate 153, and the periphery of the cap plate 151. The insulators 157 cover the first current collecting plate 130, and their edges are interposed between the inner circumferential surface of the supporter portion 122 and the first current collecting plate 130. These insulators 157 form part of the sealing cap portion 150.

[0227] A clamping portion 123 is formed at the open end of the battery can 120 to pressurize the cap plate 151 and the insulator 157. The clamping portion 123 bends the open end of the battery can 120 inward to seal the gap between the periphery of the cap plate 151 and the open end of the battery can 120. The clamping portion 123 presses and fixes the peripheries of the first current collecting plate 130 and the vent plate 153, thereby restricting movement of the first current collecting plate 130 and the vent plate 153, thereby improving the assembly stability of the battery cell 100. In addition, leakage of the sealed contents of the battery can 120 due to external impact can be prevented.

[0228] Either the first electrode sheet 11 or the second electrode sheet 12 may be electrically connected to the battery can 120 via the second current collecting plate 140. In this case, the second current collecting plate 140 may be welded to a non-coated portion 15 formed on either the first electrode sheet 11 or the second electrode sheet 12. The non-bent portion 115a and the formed portion 117 of the non-coated portion 15 may be welded to the second current collecting plate 140 using a laser. This increases the weld cross-sectional area between the non-coated portion 15 and the second current collecting plate 140, thereby increasing the cross-sectional area of ​​the current path and significantly reducing the electrical resistance of the battery cell 100. In addition, the amount of heat generated by the battery cell 100 may be reduced, thereby reducing the possibility of the battery cell 100 catching fire.

[0229] Furthermore, it goes without saying that the uncoated portion 15 formed on either the first electrode sheet 11 or the second electrode sheet 12 may be directly welded to the inner surface of the battery can 120 .

[0230] FIG. 12 is a perspective view showing the electrode assembly according to the present invention housed in a pack housing.

[0231] 12, a battery pack according to an embodiment of the present invention includes an assembly of electrically connected cylindrical battery cells 100 and a pack housing 101 that accommodates the assembly. The cylindrical battery cells 100 may be any of the battery cells 100 according to the above-described embodiments. For convenience of illustration, components such as a bus bar (not shown) for electrically connecting the cylindrical battery cells 100, a cooling unit (not shown), and external terminals (not shown) are omitted from the drawings.

[0232] The battery pack may be mounted on a vehicle 300. The vehicle 300 may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The vehicle may be a four-wheeled vehicle or a two-wheeled vehicle.

[0233] FIG. 13 is a diagram illustrating a vehicle including a battery pack according to the present invention.

[0234] 13, a vehicle 300 according to an embodiment of the present invention includes a battery cell 100 according to an embodiment of the present invention. The vehicle is operated by receiving power from the battery cell 100 according to an embodiment of the present invention.

[0235] Although the present invention has been described above with reference to exemplary drawings, the present invention is not limited to the embodiments and drawings disclosed in this specification, and various modifications may be made by those skilled in the art within the scope of the technical concept of the present invention. Furthermore, even if the effects of the configuration of the present invention are not explicitly described while describing the embodiments of the present invention, it is natural that the effects that can be predicted by the configuration should also be recognized. [Explanation of symbols]

[0236] 210 Electrode laminate 11 First electrode sheet 12 Second electrode sheet 13 Separation membrane 14 Maintenance Department 15 Plain area 16 Boundary 100 battery cells 101 Pack Housing 110 Electrode assembly 111 Electrode cell body part 112 Core 112a Uncoated area on the core side, recessed area 113 Cutting Line (Cutting Line Array) 115a Non-bent part 117 Forming Department 117a Bending section 120 Battery Can 121 Battery can body 122 Supporters Section 123 Clamping part 130 First current collecting plate 132 Center hole 140 Second current collecting plate 150 Sealing cap 151 Cap Plate 152 External terminal 153 Bent Plate 155 Lead section 157 Insulator 210 Cutter section 211 Blade 213 Vibration generating unit 215 1st communication hole 220 Second Cutter Section 221 Second Blade 223 Second vibration generating unit 230 Press Department 300 vehicles C Deleted area (plain core area) θ1, θ2 central angle

Claims

1. Step S11: stacking a first electrode sheet, a second electrode sheet, and a separator to form an electrode stack; removing a predetermined section of the uncoated portion of the electrode stack disposed adjacent to the core side; Step S12: winding the electrode stack to fabricate an electrode cell body; forming a cutting line in the axial direction on the uncoated portion of the electrode cell body portion while the cutter unit moves in the axial direction of the electrode cell body portion; and a press unit presses the bent portion provided between two adjacent cutting lines of the plain portion to lay it in a radial direction, thereby forming a formed portion; the removed predetermined section forms a recessed portion that is annularly formed so as to surround the core and that has a height that is recessed in the axial direction more than the uncoated portion that is disposed radially outward of the uncoated portion of the electrode cell body portion, on the core side; the length by which the uncoated portion in the core-side uncoated region in which the recess portion is formed extends axially outward from the electrode cell body portion is shorter than the length by which the uncoated portion in the uncoated region disposed radially outward extends axially outward from the electrode cell body portion; A method for manufacturing a battery cell.

2. A step (S11) of stacking a sheet-like first electrode sheet, a second electrode sheet, and a separation membrane to produce an electrode laminate; removing a predetermined section of the uncoated portion of the electrode stack disposed adjacent to the core side; Step S12: winding the electrode stack to fabricate an electrode cell body; forming a cutting line in the axial direction on the uncoated portion of the electrode cell body portion while the cutter unit moves in the axial direction of the electrode cell body portion; and a press unit presses the bent portion provided between two adjacent cutting lines of the plain portion to lay it in a radial direction, thereby forming a formed portion; the removed predetermined section forms a recessed portion that is annularly formed so as to surround the core and that has a height that is recessed in the axial direction more than the uncoated portion that is disposed radially outward of the uncoated portion of the electrode cell body portion, on the core side; a non-bending portion disposed between two adjacent ones of the intended bending portions is formed in a fan shape along a circumferential direction with the core portion of the electrode cell body portion as a center; A method for manufacturing a battery cell.

3. The non-bending portion disposed between two adjacent bending portions has a central angle of 30° to 180°. The method for manufacturing the battery cell of claim 2 .

4. The forming portion is formed radially around a core portion of the electrode cell body portion. The method for manufacturing the battery cell according to any one of claims 1 to 3.

5. The forming portion is formed such that a portion to be folded of the non-coating portion lies on a core portion side of the electrode cell body portion. The method for manufacturing the battery cell according to any one of claims 1 to 3.

6. The forming portion is formed along the radial direction of the electrode cell body portion. The method for manufacturing the battery cell according to any one of claims 1 to 3.

7. The cutting depth of the cutting line reaches a predetermined portion at a boundary between the non-coating portion and the maintaining portion, the predetermined portion being spaced a predetermined distance outward in the axial direction, The forming portion is formed by bending a lower end portion of the portion to be bent that corresponds to the cutting depth. The method for manufacturing the battery cell according to any one of claims 1 to 3.

8. The cutter unit cuts the non-coating portion while being vibrated by a vibration generating unit. The method for manufacturing the battery cell according to any one of claims 1 to 3.

9. the depth to which the uncoated portion in the predetermined section is removed corresponds to the depth of the cutting line; The method for manufacturing the battery cell according to any one of claims 1 to 3.

10. an electrode cell body portion in which a separator is laminated between sheet-like first and second electrode sheets, the first electrode sheet, the second electrode sheet, and the separator are wound up, and uncoated portions that are not coated with an active material layer are formed at widthwise ends of the first and second electrode sheets; a recess portion formed in an annular shape so as to surround the core, the recess portion being disposed on the core side of the uncoated portion of the electrode cell body portion and having a height that is recessed in the axial direction more than the uncoated portion disposed radially outward therefrom; a plurality of cutting lines provided in the uncoated portion of the electrode cell body portion at a radially outer portion than the recessed portion, the cutting lines being formed to a predetermined depth in the axial direction; a plurality of cutting line arrays in which the plurality of cutting lines are arranged in a line; and a plurality of forming sections formed by applying pressure to and laying down portions to be folded in the plain section that are disposed between two adjacent cutting line arrays in the circumferential direction; the length by which the uncoated portion in the core-side uncoated region in which the recess portion is formed extends axially outward from the electrode cell body portion is shorter than the length by which the uncoated portion in the uncoated region disposed radially outward extends axially outward from the electrode cell body portion; Electrode assembly.

11. An electrode cell body portion in which a separation membrane is laminated between sheet-like first and second electrode sheets, the first electrode sheet, the second electrode sheet, and the separation membrane are rolled up, and blank portions that are not coated with an active material layer are formed at the widthwise ends of the first and second electrode sheets; a recess portion formed in an annular shape so as to surround the core, the recess portion being disposed on the core side of the uncoated portion of the electrode cell body portion and having a height that is recessed in the axial direction more than the uncoated portion disposed radially outward therefrom; a plurality of cutting lines provided in the uncoated portion of the electrode cell body portion at a radially outer portion than the recessed portion, the cutting lines being formed to a predetermined depth in the axial direction; a plurality of cutting line arrays in which the plurality of cutting lines are arranged in a line; and a plurality of forming sections formed by applying pressure to and laying down portions to be folded in the plain section that are disposed between two adjacent cutting line arrays in the circumferential direction; a non-bent portion disposed between two of the forming portions adjacent in the circumferential direction is formed in a fan shape along the circumferential direction with the core portion of the electrode cell body portion as the center; Electrode assembly.

12. The non-bending portion has a central angle of 30° to 180°. The electrode assembly of claim 11.

13. the cutting depth of the cutting line reaches a predetermined portion at a boundary between the non-coating portion and the maintaining portion, the predetermined portion being spaced a predetermined distance outward in the axial direction. The electrode assembly of claim 10.

14. The recessed portion has a height corresponding to the predetermined portion in the axial direction. The electrode assembly of claim 13.

15. The bending portion is bent at a position corresponding to the predetermined portion in the axial direction. The electrode assembly of claim 13.

16. The forming portion is formed radially around a core portion of the electrode cell body portion. The electrode assembly of claim 10.

17. the forming portion is formed in a shape in which the intended bending portion is laid on a core portion side of the electrode cell body portion; The electrode assembly of claim 10.

18. the core portion is formed hollow and penetrates the center of the electrode cell body portion, and the forming portion does not obstruct the core portion in the axial direction.

18. The electrode assembly of claim 17.

19. a radial width of the recessed portion corresponding to an axial height of the intended bending portion measured from a lower end of the cutting line disposed radially adjacent to the recessed portion; The electrode assembly of claim 10.

20. An electrode assembly according to any one of claims 10 to 19; a battery can that houses the electrode assembly, is electrically connected to one of the first electrode sheet and the second electrode sheet, and has a first polarity; a sealing cap portion that seals the open end of the battery can; and a first current collecting plate having a second polarity, electrically connected to the other of the first electrode sheet and the second electrode sheet; Battery cell.

21. The first current collecting plate is welded to the forming portion.

21. The battery cell of claim 20.

22. 21. The battery cell of claim 20, Battery pack.

23. 23. The battery pack of claim 22, vehicle.

24. 20. The cutting device for manufacturing an electrode assembly according to claim 10, wherein the cutting device cuts at least a portion of an uncoated portion of an electrode assembly including an electrode cell body portion in which a first electrode sheet, a second electrode sheet, and a separator are wound in a stacked state, and an uncoated portion that is not coated with an active material layer is provided at a width direction end of at least one of the first electrode sheet and the second electrode sheet, a cutter unit that moves in the axial direction of the electrode assembly and forms a cutting line in the axial direction on the uncoated portion extending in the axial direction, Cutting device.

25. The cutter section includes a plurality of blades arranged radially and extending in an axial direction.

25. The cutting device of claim 24.

26. The cutter unit further includes a vibration generating unit.

25. The cutting device of claim 24.

27. A cutting device according to claim 24; and a press unit that applies pressure to the portion to be folded from which the uncut portion has not been cut and lays it down to form a formed portion, the pressing unit moves in a radial direction of the electrode cell body portion and lays the portion of the non-coating portion to be folded in the radial direction of the electrode cell body portion. Electrode assembly processing equipment.

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