Electrode assembly and secondary battery comprising electrode assembly

Abstract

The present disclosure provides an electrode assembly and a secondary battery comprising the electrode assembly. The electrode assembly according to the present disclosure comprises: a first electrode; a second electrode; and a separator interposed between the first electrode and the second electrode, wherein: the first electrode, the second electrode, and the separator are wound around a core portion; the first electrode includes a mixture portion in which a first active material is coated on a first electrode substrate, and an uncoated portion in which the first active material is not coated on the first electrode substrate; at least a portion of the uncoated portion includes a segment in which a heat insulating layer is embedded; and the heat insulating layer may be disposed at a position corresponding to the separator.

Description

Electrode assembly and secondary battery including electrode assembly

[0001] The present disclosure relates to an electrode assembly and a secondary battery comprising the electrode assembly.

[0002]

[0003] Unlike primary batteries, which cannot be recharged, secondary batteries are batteries capable of both charging and discharging. Low-capacity secondary batteries are used in small portable electronic devices such as smartphones, feature phones, laptop computers, digital cameras, and camcorders, while high-capacity secondary batteries are widely used as power sources for motor drive systems and power storage batteries in hybrid and electric vehicles. Such secondary batteries include an electrode assembly consisting of a positive electrode and a negative electrode, a case housing the assembly, and electrode terminals connected to the electrode assembly.

[0004] The secondary battery is wound with a separator interposed between the positive and negative electrodes and accommodated in a case, and in the accommodated state, the unoccupied portion or electrode tab of one end of the negative or positive electrode can be connected by welding to one side of the electrode terminal of the electrode assembly or the current collector plate.

[0005] Meanwhile, conventional small batteries have had limitations in terms of designable energy density. Since the amount of electrical energy that can be stored is limited relative to the battery's size and weight, there is a growing demand for large batteries with higher energy densities in applications such as electric vehicles. Consequently, attempts are being made to implement bending or compaction processes on the metal substrates of electrodes to increase the energy density and capacity of secondary batteries.

[0006] However, because the metal substrate of the electrode has high thermal conductivity, heat is applied to the separator adjacent to the metal substrate during the welding process, which can cause the separator to shrink. This shrinkage of the separator can form short circuits within the secondary battery, thereby shortening its lifespan and potentially leading to reduced battery performance due to energy loss and safety accidents.

[0007] The information described above disclosed in the background technology of this invention is intended only to enhance understanding of the background of the present invention and may therefore include information that does not constitute prior art.

[0008]

[0009] The problem that the present invention aims to solve is to provide an electrode assembly and a secondary battery including the electrode assembly for solving the above technical problem.

[0010] However, the technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems can be clearly understood by those skilled in the art from the description of the invention below.

[0011]

[0012] An electrode assembly according to one embodiment of the present invention for solving the above technical problem comprises a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode, wherein the first electrode, the second electrode, and the separator are wound around a core portion, and the first electrode comprises a composite portion coated with a first active material on a first electrode substrate and an uncoated portion not coated with the first active material on the first electrode substrate, and at least a portion of the uncoated portion comprises a segment containing an insulating layer, and the insulating layer may be disposed at a position corresponding to the separator.

[0013] According to one embodiment of the present disclosure, the segment can be bent in a direction intersecting the axial direction of the core portion.

[0014] According to one embodiment of the present disclosure, the segment includes a first section parallel to the axial direction of the core section separated by a bending point and a second section intersecting the axial direction of the core section, and the insulation layer may be disposed in at least a portion of the second section.

[0015] According to one embodiment of the present disclosure, the insulation layer may be positioned adjacent to the bend point.

[0016] According to one embodiment of the present disclosure, the insulation layer is arranged along a second section in a direction intersecting the axial direction of the core, and the width of the insulation layer may be 10% to 20% of the width of the second section.

[0017] According to one embodiment of the present disclosure, the insulation layer may be arranged to extend into a part of the first section, a bend point, and a part of the second section.

[0018] According to one embodiment of the present disclosure, the segment may include a plurality of segments formed by repeatedly cutting a portion of the unwound portion in a direction parallel to the axis of the coiled portion.

[0019] According to one embodiment of the present disclosure, a plurality of segments may overlap each other in a folded state to form a current path of a first electrode.

[0020] According to one embodiment of the present disclosure, the first electrode substrate comprises a first metal layer and a second metal layer having conductivity, and the segment may comprise an insulating layer disposed between the first metal layer and the second metal layer, and an adhesive layer interposed between the first electrode substrate and the insulating layer.

[0021] According to one embodiment of the present disclosure, the thickness of the insulating layer may be 25% to 75% of the thickness of the segment.

[0022] According to one embodiment of the present disclosure, the thickness ratio of the first metal layer and the second metal layer may be 3:1 to 1:3.

[0023] According to one embodiment of the present disclosure, the insulating layer may comprise PET, PP, PI, PC, PMMA, or a combination thereof.

[0024] According to one embodiment of the present disclosure, the adhesive layer is Al x O y , Ni x O y , Cu x O y , Cr x O y It may include (x, y > 0) or a combination thereof.

[0025] A secondary battery according to an embodiment of the present invention for solving the above technical problem comprises an electrode assembly, a current collector connected to the electrode assembly, and a case accommodating the electrode assembly and the current collector. The electrode assembly comprises a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode. The first electrode, the second electrode, and the separator are wound around a core portion. The first electrode comprises a composite portion in which a first active material is coated on a first electrode substrate, and an uncoated portion in which the first active material is not coated on the first electrode substrate. At least a portion of the uncoated portion includes a segment containing an insulating layer, and the insulating layer may be disposed at a position corresponding to the separator.

[0026] According to one embodiment of the present disclosure, a current collector plate can be joined to a segment of an electrode assembly by welding.

[0027] According to one embodiment of the present disclosure, the segment can be bent in a direction intersecting the axial direction of the core portion.

[0028] According to one embodiment of the present disclosure, the segment includes a first section parallel to the axial direction of the core section separated by a bending point, and a second section intersecting the axial direction of the core section, and the insulation layer may be disposed in at least a portion of the second section.

[0029] According to one embodiment of the present disclosure, the insulation layer may be positioned adjacent to the bend point.

[0030] According to one embodiment of the present disclosure, the segment may include a plurality of segments formed by repeatedly cutting a portion of the unwound portion in a direction parallel to the axis of the coiled portion.

[0031] According to one embodiment of the present disclosure, the first electrode substrate comprises a first metal layer and a second metal layer having conductivity, and the segment may comprise an insulating layer disposed between the first metal layer and the second metal layer, and an adhesive layer interposed between the first electrode substrate and the insulating layer.

[0032]

[0033] According to some embodiments of the present disclosure, an electrode substrate having an embedded insulating layer comprising a polymer material with low thermal conductivity is provided, thereby reducing heat transfer during the welding process of the electrode substrate and preventing thermal shrinkage of the separator.

[0034] According to some embodiments of the present disclosure, a multilayer substrate having a thermal insulation function while securing a path for the movement of current generated at the electrode is provided, thereby suppressing short circuits caused by shrinkage of the separator during the welding process, and suppressing the reduction of battery performance and the occurrence of safety accidents.

[0035] According to some embodiments of the present disclosure, by embedding an insulating layer within an electrode substrate, the risk of detachment of the insulating layer due to differences in elongation or external impact during the process can be reduced compared to a technology in which a separate insulating layer is placed outside the electrode substrate.

[0036] However, the effects obtainable through the present invention are not limited to those described above, and other unmentioned technical effects will be clearly understood by those skilled in the art from the description of the invention below.

[0037]

[0038] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0039] FIG. 1 is a schematic diagram illustrating an electrode assembly according to one embodiment of the present disclosure.

[0040] FIG. 2 is a drawing showing the process of welding an electrode assembly and a current collector plate together according to one embodiment of the present disclosure.

[0041] FIG. 3 is a plan view showing the appearance of a first electrode before winding according to one embodiment of the present disclosure.

[0042] FIG. 4 is a drawing showing the unfolded shape of a part of a wound electrode assembly according to one embodiment of the present disclosure.

[0043] FIG. 5 is a drawing showing an electrode assembly according to one embodiment of the present disclosure as viewed from the axial direction of the core.

[0044] FIG. 6 is a drawing showing a cross-section of a segment that is bent and stacked in an electrode assembly according to one embodiment of the present disclosure.

[0045] FIG. 7 is a drawing showing an enlarged cross-section of a segment according to one embodiment of the present disclosure.

[0046] FIG. 8 is a drawing showing an enlarged cross-section of a segment according to one embodiment of the present disclosure.

[0047] FIG. 9 is a drawing showing the layered structure of a segment according to one embodiment of the present disclosure.

[0048] FIG. 10 is a cross-sectional view of a secondary battery including an electrode assembly according to one embodiment of the present disclosure.

[0049]

[0050] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings. Instead, based on the principle that the inventor can appropriately define the concepts of terms to best describe their invention, they should be interpreted in a meaning and concept consistent with the technical spirit of the present invention. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention. It should be understood that various equivalents and modifications capable of replacing them may exist at the time of filing this application.

[0051] Additionally, as used herein, “comprise, include” and / or “comprising, including” specify the presence of the mentioned features, numbers, steps, actions, parts, elements, and / or groups thereof, and do not exclude the presence or addition of one or more other features, numbers, actions, parts, elements, and / or groups.

[0052] Additionally, to aid in understanding the invention, the attached drawings are not drawn to actual scale, and the dimensions of some components may be exaggerated. Furthermore, the same reference numerals may be assigned to identical components in different embodiments.

[0053] The statement that two subjects of comparison are 'identical' means that they are 'substantially identical'. Therefore, substantial identity may include deviations considered low in the industry, for example, deviations within 5%. Additionally, the statement that a parameter is uniform in a given area may mean that it is uniform from an average perspective.

[0054] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless specifically stated otherwise, the first component may also be the second component.

[0055] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0056] The statement that any component is positioned on the "upper (or lower) side" or the "upper (or lower) side" of a component implies not only that any component is positioned in contact with the upper (or lower) surface of said component, but also that another component may be interposed between said component and any component positioned on (or below) said component. Additionally, the area between the upper and lower parts of a component depicted in the drawings, or the remaining part excluding the upper and lower parts, may be referred to as a "side" or "lateral side." Furthermore, the direction facing the internal space of the component may be referred to as the "inner side," and the direction protruding into the open external space may be referred to as the "outer side." Such relative terms, such as "upper" and "upper side," may be used to describe the relationship between components depicted in the drawings, and the present disclosure is not limited by such terms.

[0057] Spatial relative terms such as "beneath," "below," "lower," "above," and "upper" may be used herein for ease of explanation to describe the relationship between one element or feature and another element(s) or feature(s) as illustrated in the drawings. Spatially relative positions are to be understood as encompassing different orientations of the device in use or operation, in addition to the orientations depicted in the figures. For example, if the device in the drawing is inverted, an element described as "below" or "below" is understood as "above" or "upper" of another element. Thus, the term "below" may encompass both the up and down directions.

[0058] Furthermore, where one component is described as being "on," "connected to," or "coupled to" another component, it should be understood that while the components may be directly connected or coupled to each other, another component may be "interposed" between each component, or that each component may be "connected," "coupled," or "coupled" through another component.

[0059] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. Additionally, the use of “may” when describing embodiments of the present disclosure relates to “one or more embodiments of the present disclosure.” Expressions such as “one or more” preceding a list of elements modify the entire list of elements and do not modify individual elements of the list.

[0060] Throughout the specification, "A and / or B" means A, B, or A and B unless specifically stated otherwise, and "C to D" means C or more and D or less, unless specifically stated otherwise.

[0061] In this specification, terms such as first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Accordingly, the first element, component, region, layer, or section discussed below may be named the second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0062] The terms used in this specification are intended to describe embodiments of the present disclosure and are not intended to limit the present disclosure.

[0063] FIG. 1 is a schematic diagram illustrating an electrode assembly according to one embodiment of the present disclosure. FIG. 2 is a diagram showing the process of welding an electrode assembly and a current collector plate together according to one embodiment of the present disclosure.

[0064] Referring to FIGS. 1 and 2, an electrode assembly (100) according to one embodiment of the present invention may include a first electrode (110), a second electrode (120), and a separator (130) interposed between the first electrode (110) and the second electrode (120). For example, the electrode assembly (100) may be formed into a jelly roll state by sequentially stacking the first electrode (110), the separator (130), and the second electrode (120) and then winding them. A cavity in which the first electrode (110), the separator (130), and the second electrode (120) do not exist may be formed inside the jelly roll (the core of the winding). The electrode assembly (100) illustrated in FIGS. 1 and 2 may represent a part of a jelly roll formed by sequentially stacking a first electrode (110), a separator (130), and a second electrode (120) and then winding them. The upper part of the illustrated electrode assembly (100) may correspond to the upper side in the direction of the winding axis of the jelly roll.

[0065] The first electrode (110) may be an electrode corresponding to the positive or negative electrode in the electrode assembly (100). The second electrode (120) may be an electrode corresponding to the opposite pole to the first electrode (110). For example, if the first electrode (110) is a positive electrode, the second electrode (120) may be a negative electrode. Conversely, if the first electrode (110) is a negative electrode, the second electrode (120) may be a positive electrode.

[0066] The first electrode (110) may include a first electrode substrate (116) and a first active material (112) coated on the first electrode substrate (116). Likewise, the second electrode (120) may include a second electrode substrate (not shown) and a second active material (122) coated on the second electrode substrate.

[0067] Here, the first electrode substrate (116) and the second electrode substrate may include a conductor. Specifically, the conductor may include a thin metal plate. For example, when the first electrode (110) is an anode, the first electrode substrate (116) may include a metal foil such as aluminum or an aluminum alloy. As another example, when the first electrode (110) is a cathode, the first electrode substrate (116) may include a metal foil such as copper, a copper alloy, nickel, or a nickel alloy. The material of the first electrode substrate (116) is not limited to the materials listed above and may be any one of the conductive metal materials used in the art. Also, in one embodiment, the first electrode substrate (116) of the first electrode (110) and the second electrode substrate (not shown) of the second electrode (120) may be composed of different materials.

[0068] The first electrode (110) may include a composite portion (110_2) on which a first active material (112) is coated on a first electrode substrate (116), and an uncoated portion (110_1) on which a part of the first electrode substrate (116) is exposed because the first active material (112) is not coated.

[0069] The composite portion (110_2) can be formed by applying a first active material (112) to one or both sides of the first electrode substrate (116). The method of applying the first active material (112) is not limited to dry or wet, and can be applied together with a binder that facilitates electrodeposition of the active material on the first electrode substrate (116).

[0070] The unworn portion (110_1) may be located at the tip of the first electrode (110). For example, the unworn portion (110_1) may be located at the end of the long side of the first electrode (110). This will be described later in FIGS. 3 and FIGS. 4.

[0071] In one embodiment, at least a portion of the unsold portion (110_1) may include a segment (114). Here, the segment (114) may be formed by notching and then folding a portion of the first electrode substrate (116) exposed in the unsold portion (110_1). The segment (114) may include an insulating layer (118) having a thermal conductivity different from that of the first electrode substrate (116). For example, the insulating layer (118) may include a polymer material with low thermal conductivity, unlike the first electrode substrate (116) which is composed of a metal having high thermal conductivity.

[0072] In one embodiment, the insulating layer (118) may be embedded in the first electrode substrate (116). Additionally, the insulating layer (118) may be positioned at a location corresponding to the separator (130). The segment (114) including the insulating layer (118) may be bent in a direction intersecting the axial direction of the core of the electrode assembly (100). Here, the insulating layer (118) may be positioned at a location that contacts the segment (114) when the separator (130) is extended in the axial direction of the core. The insulating layer (118) may be extended and positioned at other locations, including the location corresponding to the separator (130). A detailed description of the placement of the insulating layer (118) will be provided below in FIG. 7.

[0073] According to one embodiment of the present disclosure, a current collector plate (210) of a secondary battery may be joined to a segment (114) of an electrode assembly (100) by welding. For example, the current collector plate (210) may be attached to at least a portion of the first segment (114) using any one of ultrasonic welding, laser welding, resistance welding, TIG welding (Tungsten Inert Gas Welding), or any combination thereof. The attachment method is not limited to the types of welding listed above, and various methods generally used for attaching two materials may be used at the choice of a person skilled in the art.

[0074] During the process of welding the collector plate (210) and the segment (114), the welding device (200) can apply heat to the welding area. For example, when the collector plate (210) and the segment (114) are laser welded, the welding device (200) may be a laser generator.

[0075] According to some embodiments of the present disclosure, heat transfer during the welding process can be reduced through a first electrode substrate (116) having an insulating layer (118) with low thermal conductivity. Specifically, the amount of heat (204) transferred by the welded portion to the separator (130) can be smaller compared to the heat (202) applied to the welded portion. As a result, thermal shrinkage of the separator (130) can be prevented.

[0076] According to some embodiments of the present disclosure, an insulating layer (118) is embedded within a first electrode substrate (116), thereby effectively reducing the risk of detachment of the insulating layer due to differences in elongation or external impact during the process compared to a technique in which a separate insulating layer is placed outside the electrode substrate.

[0077] FIG. 3 is a plan view showing the appearance of a first electrode before winding according to one embodiment of the present disclosure. FIG. 4 is a drawing showing the unfolded shape of a part of a wound electrode assembly according to one embodiment of the present disclosure. FIG. 5 is a drawing showing the electrode assembly according to one embodiment of the present disclosure as viewed from the axial direction of the winding core.

[0078] Referring to FIGS. 3 to 5, in an electrode assembly (100) according to one embodiment of the present disclosure, a first electrode (110), a second electrode (120), and a separator (130) can be wound around a winding core (510).

[0079] In the electrode assembly (100), the first electrode (110), the second electrode (120), and the separator (130) may include the configuration described above with reference to FIGS. 1 and FIGS. 2. For example, the first electrode (110) may include a first electrode substrate (116) and a first active material (112) coated on the first electrode substrate (116). Likewise, the second electrode (120) may include a second electrode substrate (126) and a second active material (122) coated on the second electrode substrate (126). Additionally, the first electrode (110) may include a composite portion (110_2) on which a first active material (112) is coated on a first electrode substrate (116), and an uncoated portion (110_1) on which a portion of the first electrode substrate (116) is exposed so that the first active material (112) is not coated, and at least a portion of the uncoated portion (110_1) may include a segment (114).

[0080] According to one embodiment of the present disclosure, a segment (114) may be formed by repeatedly cutting or notching a portion of the unwound portion (110_1) in a direction (x) parallel to the axis (A) of the winding core portion (510). Here, there may be at least one segment (114). A plurality of segments (114) formed by cutting may be folded so as to overlap or come into contact with each other while the electrode assembly (100) is wound. That is, during the folding process, overlap between adjacent segments (114) may occur.

[0081] In one embodiment, the segment (114) may be bent in a direction that intersects the axis (A) direction of the core (510). The axis (A) of the core (510) may be parallel to the x-axis shown in FIG. 4. Accordingly, the direction intersecting the axis (A) direction of the core (510) may be the direction indicated by all arrows located on the plane formed by the y-axis and z-axis that are orthogonal to the x-axis.

[0082] For example, as illustrated in FIG. 5, a plurality of segments (114) formed on the unwound portion (110_1) of the first electrode (110) can be bent toward the winding portion (510) while intersecting with the axis (A) direction of the winding portion (510). Here, the segments (114) can be bent by a compaction process. To this end, segments (114) positioned closer to the winding portion (510) are bent in a higher priority, and segments (114) positioned closer to the outer surface (520) of the electrode assembly (100) are bent in a lower priority.

[0083] According to one embodiment of the present disclosure, the segment (114) may include a first section parallel to the axis (A) direction of the core (510) and a second section arranged in a direction intersecting the axis (A) direction of the core (510). That is, the first section of the segment (114) may be arranged in the x-axis direction, and the second section may be arranged on a plane formed by the y-axis and the z-axis. The first and second sections of the segment (114) will be described later in FIG. 7 and below.

[0084] FIG. 6 is a drawing showing a cross-section of a segment that is bent and stacked in an electrode assembly according to one embodiment of the present disclosure.

[0085] Referring to FIG. 6, in an electrode assembly according to one embodiment of the present disclosure, a plurality of segments (114_1, 114_2, 114_3) can be folded and overlapped to form a current path of a first electrode (110). As the first electrode substrate (116) comes into contact with each other in the plurality of segments (114_1, 114_2, 114_3), the current generated from the first electrode (110) can be electrically connected. Additionally, an insulating layer (118_1, 118_2, 118_3) may be embedded in each of the plurality of segments (114_1, 114_2, 114_3). Through this, a plurality of insulating layers (118_1, 118_2, 118_3) can be disposed at a position corresponding to the separator (130) in the uninsulated portion. In FIG. 6, two to three insulating layers (118_1, 118_2, 118_3) and segments (114_1, 114_2, 114_3) are shown overlapping, but the number is not limited and may vary depending on the design of the electrode assembly.

[0086] The first electrode (110), the second electrode (120), and the separator (130) may be as described above with reference to FIGS. 1 and FIGS. 2. For example, the first electrode (110) may include a first electrode substrate (116) and a first active material (112) coated on the first electrode substrate (116). Likewise, the second electrode (120) may include a second electrode substrate (126) and a second active material (122) coated on the second electrode substrate (126).

[0087] FIGS. 7 and 8 are drawings showing an enlarged cross-section of a segment according to one embodiment of the present disclosure.

[0088] Referring to FIG. 7, a segment (600) according to one embodiment may include a first section (610) parallel to the axial direction of a core (e.g., 510 in FIG. 5) and a second section (620) arranged in a direction intersecting the axial direction of the core. The first section (610) and the second section (620) may be separated based on a bending point (605) of the segment (600).

[0089] An insulating layer (680) may be placed in at least a portion of the second section (620). Through this, a first current path (692) connected to the first electrode (690) through the first section (610) and a second current path (694) connected to the first electrode (690) through the second section (620) may be formed. Compared to the first section (610), the second section (620) may have a smaller cross-sectional area due to the presence of the insulating layer (680). Therefore, the first current path (692) may have lower resistance than the second current path (692).

[0090] According to one embodiment, the insulation layer (680) may be positioned adjacent to the bend point (605). For example, one end of the insulation layer (680) may be positioned to be in contact with the bend point (605).

[0091] According to one embodiment, the insulation layer (680) may be arranged along the second section (620) in a direction intersecting the axial direction of the core. For example, the insulation layer (680) may be arranged in a shape extending toward the core from one end in contact with the bending point (605).

[0092] Here, the width (h1) of the insulation layer (680) may be about 1% to 100%, about 5% to 50%, or about 10% to 20% of the width (h2) of the second section (620). For example, the width (h1) of the insulation layer (680) may be about 0.5mm to 1mm, and the width (h2) of the second section (620) may be about 5mm.

[0093] Referring to FIG. 8, a segment (700) according to one embodiment of the present disclosure may include a first section (710) parallel to the axial direction of a core (e.g., 510 in FIG. 5) and a second section (720) arranged in a direction intersecting the axial direction of the core. The first section (710) and the second section (720) may be separated based on a bending point (705) of the segment (700).

[0094] The insulation layer (780) may be placed in part of the first section (710), the bend point (705), and part of the second section (720). Additionally, a first current path (792) connected to the first electrode (790) through the first section (710) and a second current path (794) connected to the first electrode (790) through the second section (720) may be formed.

[0095] Compared to the first section (610) of FIG. 7, the first section (710) of FIG. 8 may have a smaller cross-sectional area because an insulating layer (780) is present. Therefore, the first current path (692) of FIG. 7 may have a lower resistance than the first current path (792) of FIG. 8.

[0096] FIG. 9 is a drawing showing the layered structure of a segment according to one embodiment of the present disclosure.

[0097] Referring to FIG. 9, in a segment (900) according to one embodiment of the present disclosure, the first electrode substrate (910) comprises a first metal layer (911) and a second metal layer (912) having conductivity, and the segment (900) may comprise an insulating layer (920) and an adhesive layer (930) disposed between the first metal layer (911) and the second metal layer (912).

[0098] According to one embodiment of the present disclosure, the thickness (d3) of the insulating layer (920) may be about 25% to 75%, about 30% to 70%, or about 45% to 50% of the thickness (d0) of the segment (900). For example, the thickness (d0) of the segment (900) may be about 8 μm, and the thickness (d3) of the insulating layer (920) may be about 2 μm to 6 μm.

[0099] According to one embodiment of the present disclosure, the thicknesses of the first metal layer (911) and the second metal layer (912) may differ. For example, the ratio of the thickness (d1) of the first metal layer (911) to the thickness (d2) of the second metal layer (912) may be approximately 3:1 to 1:3.

[0100] According to one embodiment of the present disclosure, the insulating layer (920) may be made of a polymer comprising polyethylene terephthalate (PET), polyimide (PI), polyethylene (PE), polypropylene (PP), polycarbonate (PC), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene propylene rubber (EPDM), or any combination thereof, but is not limited thereto, and may be any one of the suitable compounds used as insulating materials in the art.

[0101] The adhesive layer (930) may be interposed between the first electrode substrate (910) and the insulating layer (920). For example, the adhesive layer (930) may be interposed between the first metal layer (911) and the insulating layer (920) or between the second metal layer (912) and the insulating layer (920).

[0102] According to one embodiment, the thickness (d4) of the adhesive layer (930) may be about 0.025% to 0.5%, about 0.025% to 0.3%, or about 0.05% to 0.1% of the thickness (d0) of the segment (900). For example, the thickness (d0) of the segment (900) may be about 8 μm, and the thickness (d4) of the adhesive layer (930) may be about 2 nm to 40 nm.

[0103] According to one embodiment, the adhesive layer (930) may include an oxide of a metal such as Al, Ni, Cu, or Cr. For example, the adhesive layer (930) is Al x O y , Ni x O y , Cu x O y , Cr x O y It may include, but is not limited to, compounds composed of (x, y > 0) or a combination thereof, and may correspond to any one of the suitable compounds used as adhesive materials in the art.

[0104] FIG. 10 is a cross-sectional view of a secondary battery including an electrode assembly according to one embodiment of the present disclosure.

[0105] A secondary battery according to one embodiment of the present invention may include an electrode assembly (1010), a first current collector plate (1030) connected to the electrode assembly (1010), a second current collector plate (1050), an electrode terminal (1041), a gasket (1060), a case (1020) accommodating the electrode assembly (1010) and the current collector plates (1030, 1050), and a vent plate (1042) sealing an opening on one side of the case (1020).

[0106] Here, the electrode assembly (1010) may have the same or similar configuration as the electrode assembly (100) described with reference to FIGS. 1 to 9. For example, the segment of the electrode assembly (1010) may be bent in a direction intersecting the axial direction of the core.

[0107] The electrode assembly (1010) is formed into a cylindrical jelly roll state with an empty core by winding the first electrode (1011a, 1011b), separator (1013), and second electrode (1012a, 1012b). The first electrode (1011a, 1011b) and the second electrode (1012a, 1012b) each include a coated portion (1011a, 1012a) in which an active material is applied to both sides of a substrate formed by a thin metal plate, and an uncoated portion (1011b, 1012b) in which the substrate is exposed because the active material is not applied.

[0108] The first electrode (1011a, 1011b) may be an electrode corresponding to a positive or negative electrode in a secondary battery. The second electrode (1012a, 1012b) may be an electrode corresponding to a pole opposite to the first electrode (1011a, 1011b). For example, if the first electrode (1011a, 1011b) is a positive electrode, the second electrode (1012a, 1012b) may be a negative electrode. Conversely, if the first electrode (1011a, 1011b) is a negative electrode, the second electrode (1012a, 1012b) may be a positive electrode.

[0109] For example, the first electrode (1011a, 1011b) can be formed as a positive electrode by coating a positive active material on an aluminum (Al) substrate. Additionally, the second electrode (1012a, 1012b) can be formed as a negative electrode by coating a negative active material on a copper (Cu) substrate.

[0110] The unwound portion (1011b) of the first electrode and the unwound portion (1012b) of the second electrode are respectively provided at both ends in the winding axis direction of the electrode assembly (1010), but electrode terminals (1041) and cases (1020) having different polarities are provided together in the same direction. A vent plate (1042) is located on the opposite side of the electrode terminal (1041).

[0111] The case (1020) forms the overall exterior of the secondary battery and may be formed of a conductive metal such as aluminum, aluminum alloy, stainless steel (e.g., SUS), or nickel-plated steel. Additionally, the case (1020) may provide a space for accommodating the electrode assembly (1010). The case (1020) may have an opening on one side to allow the electrode assembly (1010) to be inserted.

[0112] For example, if the secondary battery is a cylindrical secondary battery, the case (1020) may be formed into a cylinder to house the electrode assembly (1010). According to one embodiment of the present disclosure, the diameter of the case (1020) may be about 40 mm to 50 mm. For the purpose of explaining the invention, the secondary battery in FIG. 10 is shown in the shape of a cylindrical battery, but the scope of the present disclosure is not limited thereto. The secondary battery of the present invention is not limited to a cylindrical secondary battery and may include a secondary battery of any shape, such as a prismatic secondary battery, a pouch secondary battery, a coin secondary battery, etc.

[0113] The electrode terminal (1041) and the vent plate (1042) may be provided at each axial end of the case (1020) so as to face each other. The vent plate (1042) may be coupled to seal the opening of the case (1020) after the electrode assembly (1010) is inserted into the case (1020).

[0114] Specifically, the vent plate (1042) is configured to cover the opening of the case (1020) and seals the interior of the secondary battery from the external environment to prevent leakage of electrolyte, etc., protects the internal components of the secondary battery from external moisture or dust, and provides a welded or contact area to an external component (e.g., an external terminal) to electrically connect the secondary battery cell.

[0115] In FIG. 10, the vent plate (1042) is shown positioned on the upper part of the secondary battery and the electrode terminal (1041) is shown positioned on the lower part of the secondary battery, but this is not limited thereto. Depending on the usage environment or requirements of the secondary battery, the vent plate (1042) and the electrode terminal (1041) may be changed to be positioned on the lower part and the upper part of the secondary battery, respectively.

[0116] The electrode terminal (1041) is connected to the first electrode (1011a, 1011b) via the first current collector plate (1030) through a rivet (1043), and the case (1020) is connected to the second electrode (1012a, 1012b) via the second current collector plate (1050). At this time, the vent plate (1042) is electrically separated from the second current collector plate (1050) and the case (1020) and does not have polarity.

[0117] An electrode terminal (1041) connected to the first electrode (1011a, 1011b) of the electrode assembly (1010) inserted into the case (1020) from the outside is installed on one side of the case. The case (1020) has a through hole (1021) that is partially open on one side.

[0118] For example, the electrode terminal (1041) may be installed in a through hole (1021) of the case (1020) in a rivet structure. To this end, the electrode terminal (1041) may be connected to a rivet (1043). One end of the rivet (1043) is welded to the first current collector plate (1030) and positioned to pass through the through hole (1021). The electrode terminal (1041) is connected to the rivet (1043) and positioned on the outside of the case (1020). The electrode terminal (1041) may be formed to protrude above the outer surface of the case (1020) around the through hole (1021) and used as an anode terminal. At this time, the first current collector plate (1030) becomes an anode current collector plate.

[0119] At this time, the first current collector plate (1030) is electrically connected to the unoccupied portion (1011b) of the first electrode through a rivet (1043) and is electrically and mechanically connected to the electrode terminal (1041). The first current collector plate (1030) is electrically connected to the electrode terminal (1041) in a structure that reduces resistance by contacting most of the unoccupied portion (1011b) of the first electrode. The rivet (1043) included in the electrode terminal (1041) is installed in a state of electrical insulation from the case (1020) while forming a hermetic structure against the electrolyte by interposing an insulator (1023) in the through hole (1021).

[0120] Here, the insulator (1023) may be made of a polymer comprising ethylene propylene rubber (EPDM), polypropylene (PP), polyimide (PI), polyethylene terephthalate (PET), polycarbonate (PC), or any combination thereof.

[0121] As another example, the insulator (1023) may be made of a ceramic material including epoxy resin, alumina (Al2O3), zirconia (ZrO2), aramid fiber, Nomex, or any combination thereof. However, the material of the insulator (1023) is not limited to the materials listed above and may include various materials with excellent plasticity and insulation properties depending on the choice.

[0122] In one embodiment, the first current collector plate (1030) may include a metal plate (1031) comprising at least one bridge (1032). For example, the first current collector plate (1030) may be composed of a conductive metal, specifically a conductive metal such as nickel, aluminum, copper, silver, zinc, tin, stainless steel (e.g., SUS), or nickel-plated steel or any combination thereof (alloy). Additionally, the metal plate (1031) and the bridge (1032) constituting the first current collector plate (1030) may all be made of the same material to form a single unit.

[0123] Here, the bridge (1032) of the first collector plate (1030) can be configured to break when a current exceeding a set value flows. For example, the bridge (1032) normally operates as part of a circuit through which current flows, but when a current exceeding the necessary amount flows, it can act as a fuse that melts due to the heat generated to cut off the circuit.

[0124] An insulating tape (1045) may be attached to one side of the first current collector plate (1030). The insulating tape (1045) may be interposed between the first current collector plate (1030) and the case (1020) or between the uninsulated portion (1011b) of the first electrode and the case (1020) to perform the function of electrically insulating each component. In one embodiment, the central portion of the insulating tape (1045) may include a perforation (1046) corresponding to the shape of a rivet (1043) so that the rivet (1043) can come into contact with the first current collector plate (1030). Additionally, the insulating tape (1045) may include a side wall (10410) to wrap around a part of the electrode assembly (1010).

[0125] Additionally, the case (1020) is provided with a fully open opening (1022) to allow the electrode assembly (1010) to be inserted on the other side. The vent plate (1042) seals the opening (1022) after the electrode assembly (1010) is inserted into the case (1020) and is electrically separated from the case (1020).

[0126] At this time, the second current collector plate (1050) is electrically connected to the non-electrical portion (1012b) of the second electrode and is electrically connected to the case (1020). The second current collector plate (1050) is connected to the case (1020) in a structure that reduces resistance by contacting most of the non-electrical portion (1012b) of the second electrode.

[0127] The second current collector plate (1050) includes a bottom portion (1051) welded to the non-bonded portion (1012b) of the second electrode and a wing portion (1052) formed adjacent to the bottom portion (1051) and welded to the beading portion (1029). The second current collector plate (1050) is formed by cutting and bending a circular plate, and is provided with a plurality of bottom portions (1051) and wing portions (1052), respectively, and is arranged alternately with one another along the circumferential direction. In one embodiment, the wing portion (1052) can repeatedly form an axial (upward) bend and a radial (outer) bend of the electrode assembly (1010).

[0128] In one embodiment, when the uncoated portion (1012b) of the second electrode and the bottom portion (1051) of the second current collector plate (1050) are welded, the bottom portion (1051) can form a weld line in the diameter direction of the second current collector plate (1050). Thus, the bottom portion (1051) can be evenly connected along the circumferential direction in the area of ​​the uncoated portion (1012b) of the second electrode, and the wing portion (1052) can be evenly connected along the circumferential direction in the area of ​​the beading portion (1029). This enables a uniform current flow along the circumferential direction from the uncoated portion (1012b) of the second electrode to the entire area of ​​the beading portion (1029) of the case (1020).

[0129] Additionally, the second collector plate (1050) is provided with a hole (1053) in the center, so it can absorb and mitigate deformation caused by welding between the bottom part (1051) and the non-welded part (1012b) of the second electrode, as well as vibrations and shocks that may be transmitted between the wing part (1052) and the bottom part (1051). The hole (1053) may have a size within a range that can absorb vibrations and shocks without increasing current resistance between the wing part (1052) and the bottom part (1051).

[0130] The vent plate (1042) is electrically separated from the second current collector plate (1050) and installed in the opening (1022) of the case (1020) by a clamping process. Alternatively, the vent plate (1042) is installed in the opening (1022) of the case (1020) through a welding process. Due to the connection of the second current collector plate (1050), the case (1020) can be used as a negative terminal. At this time, the second current collector plate (1050) becomes a negative current collector plate.

[0131] The vent plate (1042) may have a notch (1044) formed on its inner surface. The notch (1044) can be cut open to release internal pressure from the secondary battery to the outside in the event of an abnormal event in the secondary battery, thereby preventing a secondary explosion. Specifically, the notch (1044) is designed to be easily cut open by receiving concentrated internal pressure during an abnormal event. The notch (1044) may be formed over the entire area along the circumferential direction of the vent plate (1042), or it may be formed in multiple locations spaced apart at set intervals.

[0132] The gasket (1060) is interposed between the second current collector plate (1050) and the vent plate (1042) and between the second current collector plate (1030) and the case (1020), and acts as a seal through the beading portion (1029) or the clamping process. Additionally, the gasket (1060) can form an airtight structure against the electrolyte between the second current collector plate (1030) and the opening (1022) of the case (1020).

[0133] For example, the gasket (1060) may include polymer materials such as polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE or Teflon), polyethylene (PE), epoxy resin, silicone, polyvinylidene fluoride (PVDF), polypropylene (PP), polyacrylonitrile (PAN), or polyethylene oxide (PEO), or ceramics, but is not limited thereto, and may be any one of the suitable compounds used as insulating materials in the industry.

[0134] The sealing tape (1090) can be attached to wrap the outer surface of the jelly roll of the electrode assembly (1010) at least once. Additionally, the electrode assembly (1010) is inserted into the case (1020) with the sealing tape (1090) attached, and the sealing tape (1090) can be positioned between the electrode assembly (1010) and the case (1020). Thus, the secondary battery assembled is prevented from moving the electrode assembly (1010) in the up-down or forward-backward direction inside the case (1020), thereby preventing the separation of terminals or damage to the components, and can suppress cracks in the case (1020) or the electrode assembly (1010) caused by excessive expansion of the electrode assembly (1010) even when the electrode assembly (1010) expands due to charging and discharging.

[0135] A secondary battery according to one embodiment of the present invention may be applied to automobiles, mobile phones, and / or various types of electric devices, etc., but the present invention is not limited thereto.

[0136] According to some embodiments of the present disclosure, a multilayer substrate having an insulating function while securing a path for the movement of current generated at the electrode is provided, thereby suppressing short circuits caused by separator shrinkage and suppressing the reduction of battery performance and the occurrence of safety accidents.

[0137] Although the present invention has been described above by means of limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs. Since various substitutions, modifications, and changes are possible within the scope of the technical spirit of the present invention without departing from it, by those skilled in the art to which the present invention belongs, the present invention is not limited by the aforementioned embodiments and attached drawings.

Claims

1. First electrode; Second electrode; and It includes a separator interposed between the first electrode and the second electrode, and The first electrode, the second electrode, and the separator are wound around a core, and The first electrode above is, A composite portion having a first active material coated on a first electrode substrate; and The above first electrode substrate includes an uncoated portion where the first active material is not coated, and At least a portion of the above-mentioned uninsulated part comprises a segment containing an insulating layer, and The above insulating layer is an electrode assembly positioned at a location corresponding to the above separator.

2. In Paragraph 1, The above segment is an electrode assembly bent in a direction intersecting the axial direction of the above core.

3. In Paragraph 2, The above segment includes a first section parallel to the axial direction of the core section separated by a bending point, and a second section intersecting the axial direction of the core section. The above insulation layer is an electrode assembly disposed in at least a portion of the above second section.

4. In Paragraph 3, The above insulation layer is positioned adjacent to the above bend point, forming an electrode assembly.

5. In Paragraph 3, The above insulation layer is arranged along the second section in a direction intersecting the axial direction of the coil core, and An electrode assembly in which the width of the insulation layer is 10% to 20% of the width of the second section.

6. In Paragraph 3, The above-mentioned insulating layer is an electrode assembly extending and disposed in part of the first section, the bend point, and part of the second section.

7. In Paragraph 2, The above-mentioned segment comprises a plurality of segments formed by repeatedly cutting a portion of the above-mentioned unwound portion in a direction parallel to the axis of the above-mentioned core portion, an electrode assembly.

8. In Paragraph 7, The above plurality of segments overlap each other in a bent state to form a current path of the first electrode, forming an electrode assembly.

9. In Paragraph 1, The above first electrode substrate includes a first metal layer and a second metal layer having conductivity, and The above segment is, The insulating layer disposed between the first metal layer and the second metal layer; and An electrode assembly comprising an adhesive layer interposed between the first electrode substrate and the insulating layer.

10. In Paragraph 1, An electrode assembly in which the thickness of the insulation layer is 25% to 75% of the thickness of the segment.

11. In Paragraph 9, An electrode assembly in which the thickness ratio of the first metal layer and the second metal layer is 3:1 to 1:

3.

12. In Paragraph 1, The above insulating layer comprises PET, PP, PI, PC, PMMA, or a combination thereof, in an electrode assembly.

13. In Paragraph 9, The adhesive layer above is Al x O y , Ni x O y , Cu x O y , Cr x O y An electrode assembly comprising (x, y > 0) or a combination thereof.

14. Electrode assembly; A current collector plate connected to the electrode assembly above; and It includes a case that accommodates the electrode assembly and the current collector plate, The above electrode assembly is, First electrode; Second electrode; and It includes a separator interposed between the first electrode and the second electrode, and The first electrode, the second electrode, and the separator are wound around a core, and The first electrode above is, A composite portion having a first active material coated on a first electrode substrate; and The above first electrode substrate includes an uncoated portion where the first active material is not coated, and At least a portion of the above-mentioned uninsulated part comprises a segment containing an insulating layer, and A secondary battery in which the above insulating layer is positioned at a location corresponding to the above separator.

15. In Paragraph 14, A secondary battery in which the above current collector plate is joined to the above segment of the above electrode assembly by welding.

16. In Paragraph 14, The above segment is a secondary battery that is bent in a direction intersecting the axial direction of the above core.

17. In Paragraph 16, The above segment includes a first section parallel to the axial direction of the core section separated by a bending point, and a second section intersecting the axial direction of the core section. The above insulation layer is disposed in at least a portion of the above second section, a secondary battery.

18. In Paragraph 17, A secondary battery in which the above insulation layer is positioned adjacent to the above bend point.

19. In Paragraph 16, A secondary battery comprising a plurality of segments formed by repeatedly cutting a portion of the unwound portion in a direction parallel to the axis of the coil core.

20. In Paragraph 14, The above first electrode substrate includes a first metal layer and a second metal layer having conductivity, and The above segment is, The insulating layer disposed between the first metal layer and the second metal layer; and A secondary battery comprising an adhesive layer interposed between the first electrode substrate and the insulating layer.

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