Electrode assembly and method for manufacturing electrode assembly

Abstract

The present disclosure provides an electrode assembly and a method for manufacturing an electrode assembly. The electrode assembly according to the present disclosure comprises a first electrode, a separator stacked on the first electrode, and a second electrode stacked on the separator. The first electrode comprises: a substrate layer including a conductor; a mixture layer formed on the substrate layer; a first reinforcing substrate coupled to an uncoated portion of the substrate layer; and a first insulating coating layer formed on the first reinforcing substrate, wherein at least a portion of an overlapping portion between the first reinforcing substrate and the first insulating coating layer is located on the uncoated portion.

Description

Electrode assembly and method for manufacturing the electrode assembly

[0001] The present disclosure relates to an electrode assembly and a method for manufacturing an electrode assembly.

[0002] 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.

[0003] Although rechargeable batteries are used in various environments due to their excellent electrical characteristics, 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 size and weight of the battery, there is a gradually increasing demand for large batteries with higher energy density in applications such as electric vehicles.

[0004] However, during the charging and discharging processes of secondary batteries, changes in chemical energy cause the volume of the electrode assembly to expand or contract as ions move within the battery to transfer electrical energy. The repeated contraction and expansion occurring during charging and discharging form uneven short circuits within the secondary battery, thereby shortening its lifespan and leading to reduced battery performance and safety accidents due to energy loss.

[0005] In particular, when welding between metal substrates is performed within an electrode assembly to form electrode tabs, fracture of the separator (or membrane) at the weld surface occurs as a defect. It is necessary to secure means to enhance the safety of the electrode assembly to prevent such defects.

[0006] 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.

[0007] The problem that the present invention aims to solve is to provide an electrode assembly and a method for manufacturing the electrode assembly to solve the above technical problem.

[0008] 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.

[0009] An electrode assembly according to one embodiment of the present invention for solving the above technical problem comprises a first electrode, a separator stacked on the first electrode, and a second electrode stacked on the separator, wherein the first electrode comprises a substrate layer including a conductor, a composite layer formed on the substrate layer, a first reinforcing substrate coupled to a non-reinforcing portion of the substrate layer, and a first insulating coating layer formed on the first reinforcing substrate, and at least a portion of the overlapping portion between the first reinforcing substrate and the first insulating coating layer may be located on the non-reinforcing portion.

[0010] According to one embodiment of the present disclosure, the substrate layer comprises a film layer made of an insulating material, a first metal layer coated on one side of the film layer, and a second metal layer coated on the other side of the film layer so as to face the first metal layer, and the first reinforcing material may be bonded to the uncoated portion of the first metal layer.

[0011] According to one embodiment of the present disclosure, the electrode assembly may further include a second reinforcing material coupled to a second metal layer and a second insulating coating layer formed on the second reinforcing material.

[0012] According to one embodiment of the present disclosure, the first reinforcing member may be bent to be electrically connected to the second reinforcing member.

[0013] According to one embodiment of the present disclosure, the width of the unworn portion of the substrate layer may be greater than or equal to the width of the overlapping portion between the first reinforcing substrate and the first insulating coating layer.

[0014] According to one embodiment of the present disclosure, the width of the unworn portion of the substrate layer may be 4% to 6% of the width of the substrate layer.

[0015] According to one embodiment of the present disclosure, the unbonded portion of the substrate layer and the first reinforcing material can be joined by ultrasonic welding.

[0016] According to one embodiment of the present disclosure, the first insulating coating layer may comprise polyethylene, polypropylene, polyetherimide, polyacetal, polysulfone, polyetheretherketone, polyester, polyamide, ethylene-vinyl acetate copolymer, polystyrene, polytetrafluoroethylene, polysiloxane, polyimide, or any combination thereof.

[0017] According to one embodiment of the present disclosure, one end of the composite layer may be in contact with the first insulating coating layer.

[0018] According to one embodiment of the present disclosure, one end of the composite layer in contact with the first insulating coating layer may be perpendicular to the substrate layer.

[0019] According to one embodiment of the present disclosure, a portion of the first insulating coating layer may be interposed between the composite layer and the first reinforcing material.

[0020] A method for manufacturing an electrode assembly according to an embodiment of the present invention for solving the above technical problem comprises the steps of: providing a substrate layer including a conductor; bonding a first reinforcing substrate to a non-reinforcing portion of the substrate layer; forming a first insulating coating layer on the first reinforcing substrate; forming a composite layer on a part of the substrate layer to manufacture a first electrode; and stacking the first electrode, a separator, and a second electrode, wherein at least a portion of the overlapping portion between the first reinforcing substrate and the first insulating coating layer may be located on the non-reinforcing portion.

[0021] According to one embodiment of the present disclosure, the substrate layer comprises a film layer made of an insulating material, a first metal layer coated on one side of the film layer, and a second metal layer coated on the other side of the film layer facing the first metal layer, and the step of attaching a first reinforcing material to an uncoated portion of the substrate layer may include the step of attaching a first reinforcing material to an uncoated portion of the first metal layer.

[0022] According to one embodiment of the present disclosure, the manufacturing method may further include the steps of bonding a second reinforcing material to a second metal layer and forming a second insulating coating layer on the second reinforcing material.

[0023] According to one embodiment of the present disclosure, the manufacturing method may further include the step of bending the first reinforcing material so as to be electrically connected to the second reinforcing material.

[0024] According to one embodiment of the present disclosure, the step of joining a first reinforcing material to an unoccupied portion of a substrate layer may include the step of joining the unoccupied portion and the first reinforcing material by ultrasonic welding.

[0025] According to one embodiment of the present disclosure, the step of manufacturing a first electrode may include the step of forming one end of a composite layer to be in contact with a first insulating coating layer.

[0026] According to one embodiment of the present disclosure, the step of forming a first insulating coating layer on a first reinforcing substrate may include the step of forming the end of the first insulating coating layer facing the composite layer so as to be perpendicular to the substrate layer.

[0027] A secondary battery according to an embodiment of the present invention for solving the above technical problem may include an electrode assembly formed by stacking a first electrode, a separator, and a second electrode, an electrolyte, and a case for housing the electrode assembly. The first electrode includes a substrate layer including a conductor, a composite layer formed on the substrate layer, a first reinforcing substrate coupled to a non-reinforcing portion of the substrate layer, and a first insulating coating layer formed on the first reinforcing substrate, and at least a portion of the overlapping portion between the first reinforcing substrate and the first insulating coating layer may be located on the non-reinforcing portion.

[0028] According to one embodiment of the present disclosure, an electrode assembly is formed by winding a stacked first electrode, a separator, and a second electrode, and a first reinforcing member may be bent toward the core of the electrode assembly.

[0029] According to some embodiments of the present disclosure, an insulating coating layer on a reinforcing substrate can prevent the occurrence of a short circuit by suppressing the breakage that occurs due to the expansion of the anode or cathode during the charging and discharging of the electrode assembly.

[0030] According to some embodiments of the present disclosure, by forming an insulating coating layer overlapping the non-solid portion of the substrate layer and the region corresponding to the non-solid portion, stability can be improved, and at the same time, the capacity of the electrode assembly can be increased by increasing the ratio of the composite layer in the electrode.

[0031] According to some embodiments of the present disclosure, in the process of forming a composite layer of an electrode assembly, a reinforcing material pre-bonded to one surface of the substrate layer's non-bonded portion acts as a guide to uniformly coat the active material. This increases the lifespan of the secondary battery and suppresses lithium precipitation, reduced battery performance, and safety accidents caused by uneven coating of the active material.

[0032] 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.

[0033] 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.

[0034] FIG. 1 is a schematic diagram illustrating an electrode assembly according to one embodiment of the present disclosure.

[0035] FIG. 2 is a plan view showing a cross- section of a first electrode according to one embodiment of the present disclosure.

[0036] FIG. 3 is a plan view showing the shape of a first electrode before bending according to one embodiment of the present disclosure.

[0037] FIG. 4 is a plan view showing the shape of the first electrode after bending according to one embodiment of the present disclosure.

[0038] FIG. 5 is a plan view showing a cross- section of a first electrode according to one embodiment of the present disclosure.

[0039] FIG. 6 is a plan view showing a cross-section of an electrode according to one embodiment of the present disclosure.

[0040] FIG. 7 is a cross-sectional view of a secondary battery according to one embodiment of the present disclosure.

[0041] FIG. 8 is a drawing showing the surface of the substrate layer of a first electrode that has been ultrasonically welded according to one embodiment of the present disclosure.

[0042] FIG. 9 is a flowchart illustrating an example of a method for manufacturing an electrode assembly according to the present disclosure.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] The terms used in this specification are intended to describe embodiments of the present disclosure and are not intended to limit the present disclosure.

[0056] FIG. 1 is a schematic diagram illustrating an electrode assembly according to one embodiment of the present disclosure.

[0057] Referring to FIG. 1, an electrode assembly (100) according to one embodiment of the present invention may be formed by stacking a first electrode (110), a separator (130), and a second electrode (120). The electrode assembly (100) may include a first electrode (110), a separator (130) stacked on the first electrode (110), and a second electrode (120) stacked on the separator (130).

[0058] For example, the electrode assembly (100) can 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 can be formed inside the jelly roll (the core of the winding).

[0059] 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.

[0060] In one embodiment, the first electrode (110) may include a substrate layer (112) and a composite layer (114) formed on the substrate layer (112). Here, the substrate layer (112) may include a conductor. Specifically, the substrate layer (112) may include a thin metal plate.

[0061] For example, when the first electrode (110) is an anode, the substrate layer (112) may include a metal foil such as aluminum or an aluminum alloy. As another example, when the first electrode (110) is a cathode, the substrate layer (112) may include a metal foil such as copper, a copper alloy, nickel, or a nickel alloy. The material of the substrate layer (112) is not limited to the materials listed above and may be any one of the conductive metal materials used in the industry. Also, in one embodiment, the substrate layer (112) of the first electrode (110) and the substrate layer (not shown) of the second electrode (120) may be composed of different materials.

[0062] For example, the substrate layer (112) may include a film layer made of an insulating material and a metal layer coated on the film layer. The composition of the substrate layer (112) will be described later in FIG. 2.

[0063] The composite layer (114) can be formed by applying an active material to one or both sides of the substrate layer (112). The first electrode (110) shown in FIG. 1 has an active material applied to one side and the other side of the substrate layer (112). The method of applying the active material is not limited to dry or wet, and can be applied together with a binder that facilitates electrodeposition of the active material on the substrate layer (112). Additionally, the first electrode (110) may include a composite portion (110_1) in which the composite layer (114) is formed by applying an active material to the substrate layer (112), and an uncoated portion (110_2) in which a part of the substrate layer (112) is exposed because the composite layer (114) is not formed. Here, the first uncoated portion (110_2) may be located at the tip of the first electrode (110).

[0064] In one embodiment, the first electrode (110) may include a first reinforcing material (116) that is coupled to a non-reinforcing portion (110_2) of the substrate layer (112). Specifically, the first reinforcing material (116) may be attached to one side of the non-reinforcing portion (110_2) of the substrate layer (112) located at the tip of the first electrode (110). The length of the first reinforcing material (116) may be greater than or equal to the length of the non-reinforcing portion (110_2) of the substrate layer (112). In this way, a portion of the first reinforcing material (116) may overlap with the non-reinforcing portion (110_2) of the substrate layer (112), and the remaining portion of the first reinforcing material (116) may not overlap with the non-reinforcing portion (110_2) but protrude from the non-reinforcing portion (110_2), thereby substantially extending the tip of the first electrode (110).

[0065] According to one embodiment, the first reinforcing material (116) may include the same material as the substrate layer (112). For example, when the first electrode (110) is an anode, the first reinforcing material (116) may be formed of a metal such as aluminum or an aluminum alloy. In another embodiment, when the first electrode (110) is a cathode, the first reinforcing material (116) may be formed of a metal such as copper, a copper alloy, nickel, or a nickel alloy.

[0066] According to one embodiment, the unbonded portion (110_2) of the substrate layer (112) and the first reinforcing substrate (116) can be joined by ultrasonic welding. This will be described later in FIG. 8.

[0067] In one embodiment, the first electrode (110) may include a first insulating coating layer (118) formed on a first reinforcing substrate (116). At least a portion of the overlapping portion between the first reinforcing substrate (116) and the first insulating coating layer (118) may be located on the uninsulated portion (110_2). For example, the width of the overlapping portion between the first reinforcing substrate (116) and the first insulating coating layer (118) may be defined as h2. The width (h1) of the uninsulated portion (110_2) may be greater than or equal to the width (h2) of the overlapping portion between the first reinforcing substrate (116) and the first insulating coating layer (118). The entire overlapping portion between the first reinforcing substrate (116) and the first insulating coating layer (118) may be located on the uninsulated portion (110_2).

[0068] The first insulating coating layer (118) may comprise polyethylene, polypropylene, polyetherimide, polyacetal, polysulfone, polyetheretherketone, polyester, polyamide, ethylene-vinyl acetate copolymer, polystyrene, polytetrafluoroethylene, polysiloxane, polyimide, or any combination thereof. The first insulating coating layer (118) is not limited to the types of materials listed above and may comprise various materials generally used for insulation, depending on the choice of a person skilled in the art.

[0069] According to some embodiments of the present disclosure, the stability of the electrode assembly (100) can be improved by forming a first insulating coating layer (118) overlapping on a first reinforcing substrate (116) in an area corresponding to the uninsulated portion (110_2) of the substrate layer (112). When compared to an electrode assembly in which the first reinforcing substrate (116) and the first insulating coating layer (118) are not formed overlappingly in an area corresponding to the uninsulated portion (110_2) but are formed separately, the capacity of the electrode assembly (100) can be increased by relatively increasing the amount of the composite portion (110_1) in the first electrode (110) according to the embodiment of the present disclosure. For example, the width (h1) of the uninsulated portion (110_2) of the substrate layer (112) may be 3% to 7%, 3% to 6%, or 4% to 6% of the width (h3) of the substrate layer (112).

[0070] Although not illustrated, according to one embodiment, the second electrode (120) may include a configuration corresponding to the configuration of the first electrode (110). For example, the second electrode (120) may include a substrate layer, a composite layer containing an active material, a composite portion in which the composite layer is formed, and a non-composite portion in which the composite layer is not formed. The non-composite portion of the second electrode (120) and the non-composite portion (110_2) of the first electrode (110) may be arranged in opposite directions.

[0071] FIG. 2 is a plan view showing a cross- section of a first electrode according to one embodiment of the present disclosure.

[0072] Referring to FIG. 2, the first electrode (210) may include a substrate layer (250) and a composite layer (214) formed on the substrate layer (250). As shown in FIG. 2, the composite layer (214) may be formed on one side and the other side of the substrate layer (250). The first electrode (210) may include a composite portion (210_1) where the composite layer (214) is formed and a non-composite portion (210_2) where the composite layer (214) is not formed.

[0073] According to one embodiment, the substrate layer (250) may include a film layer (252) made of an insulating material, a first metal layer (254) coated on one side of the film layer (252), and a second metal layer (256) coated on the other side of the film layer (252). Specifically, the film layer (252) may be interposed between the first metal layer (254) and the second metal layer (256) so that the second metal layer (256) faces the first metal layer (254) with the film layer (252) in between. The first metal layer (254) and the second metal layer (256) may be formed from the same metal foil.

[0074] In one embodiment, when the first electrode (110) is an anode, the first metal layer (254) and the second metal layer (256) may be formed from a metal foil such as aluminum or an aluminum alloy. In another embodiment, when the first electrode (110) is a cathode, the first metal layer (254) and the second metal layer (256) may be formed from a metal foil such as copper, a copper alloy, nickel, or a nickel alloy. The material of the first metal layer (254) and the second metal layer (256) is not limited to the materials listed above and may be any one of the conductive metal materials used in the art.

[0075] The film layer (252) may be made of a polymer comprising polyethylene terephthalate (PET), polyimide (PI), polyethylene (PE), polypropylene (PP), polycarbonate (PC), 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.

[0076] The first electrode (210) may include a first insulating coating layer (218) formed on the first reinforcing substrate (216). At least a portion of the overlapping area between the first reinforcing substrate (216) and the first insulating coating layer (218) may be located on the uninsulated portion (210_2).

[0077] Other details regarding the configuration are as described above with reference to Fig. 1.

[0078] FIG. 3 is a plan view showing the shape of a first electrode before a bending process according to one embodiment of the present disclosure. FIG. 4 is a plan view showing the shape of a first electrode after a bending process according to one embodiment of the present disclosure.

[0079] Referring to FIGS. 3 and 4, a first electrode (310_1, 310_2) according to one embodiment may include a substrate layer (350) and a composite layer (314) formed on the substrate layer (350). The composite layer (314) may be formed on one side and the other side of the substrate layer (350). The substrate layer (350) may include a film layer (352) made of an insulating material, a first metal layer (354) coated on one side of the film layer (352), and a second metal layer (356) coated on the other side of the film layer (352).

[0080] The first reinforcing material (316) may be bonded to the unbonded portion of the first metal layer (354). The first insulating coating layer (318) may be formed on the first reinforcing material (316). At least a portion of the first insulating coating layer (318) may belong to an area corresponding to the unbonded portion.

[0081] At least some of the overlapping portion between the first reinforcing material (316) and the first insulating coating layer (318) may be located on the uninsulated portion.

[0082] For example, a portion of the first insulating coating layer (318) may belong to an area corresponding to a non-existent portion, and the remaining portion may not belong to an area corresponding to a non-existent portion.

[0083] For example, the area of ​​the first insulating coating layer (318) may be equal to or larger than the area where the uncoated portion of the substrate layer (350) and the first reinforcing material (316) overlap. A portion of the first insulating coating layer (318) may be placed outside the area where the uncoated portion of the substrate layer (350) and the first reinforcing material (316) overlap, and the remaining portion of the first insulating coating layer (318) may be placed within the area.

[0084] In one embodiment, the first electrode (310_1, 310_2) may further include a second reinforcing material (326) coupled to the second metal layer (256) and a second insulating coating layer (328) formed on the second reinforcing material (326). At least a portion of the overlapping portion between the second reinforcing material (326) and the second insulating coating layer (328) may be located on the uninsulated portion.

[0085] The second reinforcing material (326) may be bonded to the uncoated portion of the second metal layer (356). The second insulating coating layer (328) may be formed on the second reinforcing material (326) for the area where the uncoated portion of the substrate layer (350) and the second reinforcing material (326) overlap, and for the area outside of said area. For example, the area of ​​the second insulating coating layer (328) may be equal to or greater than the area where the uncoated portion of the substrate layer (350) and the second reinforcing material (326) overlap. A portion of the second insulating coating layer (328) may be placed outside the area where the uncoated portion of the substrate layer (350) and the second reinforcing material (326) overlap, and the remaining portion of the second insulating coating layer (328) may be placed within the area.

[0086] As illustrated in FIG. 3, in a substrate layer (350) according to one embodiment, the length of the film layer (352) may be greater than or equal to the length of the first metal layer (354) and the second metal layer (356). Accordingly, a portion of the film layer (352) may be exposed on one side of the substrate layer (350). As a result, the first metal layer (354) and the second metal layer (356) may be electrically insulated unless otherwise configured.

[0087] Referring to FIG. 4, a first reinforcing member (316) according to one embodiment of the present disclosure may be bent so as to be electrically connected to a second reinforcing member (326). Specifically, a portion of the first reinforcing member (316) that is not covered by the first insulating coating layer (318) may be deformed and bent so as to come into contact with the second reinforcing member (326). Through this, the first metal layer (354) connected to the first reinforcing member (316) and the second metal layer (356) connected to the second reinforcing member (326) may be electrically connected.

[0088] In one embodiment, the second reinforcing member (326) may be bent in the same direction as the first reinforcing member (316) by deforming a portion of the second reinforcing member (326) that is not covered by the second insulating coating layer (328). In one embodiment, the bending direction of the first reinforcing member (316) and / or the second reinforcing member (326) may be directed toward the core of the electrode assembly.

[0089] FIG. 5 is a plan view showing a cross-section of a first electrode according to one embodiment of the present disclosure. FIG. 6 is also a plan view showing a cross-section of an electrode according to one embodiment of the present disclosure.

[0090] Referring to FIG. 5, in a first electrode (510) according to one embodiment, one end (554) of the composite layer (514) may be in contact with the first insulating coating layer (518). Specifically, the one end (554) of the composite layer (514) in contact with the first insulating coating layer (518) may be formed perpendicular to the substrate layer (512). Additionally, a portion of the first insulating coating layer (518) may be interposed between the composite layer (514) and the first reinforcing substrate (516). A portion of the first insulating coating layer (518) may be formed on the uninsulated portion, and the remaining portion of the first insulating coating layer (518) may be formed on the first reinforcing substrate (516).

[0091] The first reinforcing material (516) can be bonded to the uncoated portion. At least a portion of the overlapping area between the first reinforcing material (516) and the first insulating coating layer (518) may be located on the uncoated portion.

[0092] According to some embodiments of the present disclosure, before the composite layer (514) of the first electrode (510) is formed, a first reinforcing material (516) and a first insulating coating layer (518) may be formed in advance on one surface of the uncoated portion of the substrate layer (512). The first insulating coating layer (518) acts as a guide when forming the composite layer (514) to make the thickness of the composite layer (514) uniform. Through this, the lifespan of the secondary battery can be increased, and lithium deposition, reduced battery performance, and safety accidents caused by uneven application of active material can be suppressed.

[0093] Referring to FIG. 6, one end (654) of the composite layer (614) at the electrode (610) may be spaced apart from the insulating coating layer (618) formed on the reinforcing substrate (616). Specifically, one end (654) of the composite layer (614) positioned around the insulating coating layer (618) may be inclined with respect to the substrate layer (612). As the charging and discharging of the secondary battery proceeds, an uneven electric field is applied to the inclined one end (654) of the composite layer (614), which may lead to lithium deposition and a decrease in battery performance.

[0094] FIG. 7 is a cross-sectional view of a secondary battery according to one embodiment of the present disclosure.

[0095] Referring to FIG. 7, a secondary battery according to one embodiment of the present disclosure includes an electrode assembly (710) that performs charging and discharging, a case (720) that accommodates the electrode assembly (710) and an electrolyte, a first current collector plate (730) connected to the electrode assembly (710), a second current collector plate (750), an electrode terminal (741), a vent plate (742) that seals an opening on one side of the case (720), and a gasket (760).

[0096] Here, the first electrode (711a, 711b) may have the same or similar configuration as the first electrode (110, 310_1, 310_2, 510) described with reference to FIGS. 1 to 6. In addition, the electrode assembly (710) including the first electrode (711a, 711b) and the second electrode (712a, 712b) may have the same or similar configuration as the electrode assembly (100) described with reference to FIGS. 1 to 6.

[0097] For example, the first electrode (711a, 711b) includes a substrate layer containing a conductor, a composite layer formed on the substrate layer, a first reinforcing material coupled to the uncoated portion (711b) of the substrate layer, and a first insulating coating layer formed on the first reinforcing material corresponding to the uncoated portion (711b), and the first reinforcing material can be bent toward the core portion of the electrode assembly (710).

[0098] The electrode assembly (710) is formed into a cylindrical jelly roll state with an empty core by winding the first electrode (711a, 711b), separator (713), and second electrode (712a, 712b). The first electrode (711a, 711b) and the second electrode (712a, 712b) each include a coated portion (711a, 712a) in which an active material is applied to both sides of a substrate formed by a thin metal plate, and an uncoated portion (711b, 712b) in which the substrate is exposed and the active material is not applied.

[0099] The first electrode (711a, 711b) may be an electrode corresponding to a positive or negative electrode in a secondary battery. The second electrode (712a, 712b) may be an electrode corresponding to a pole opposite to the first electrode (711a, 711b). For example, if the first electrode (711a, 711b) is a positive electrode, the second electrode (712a, 712b) may be a negative electrode. Conversely, if the first electrode (711a, 711b) is a negative electrode, the second electrode (712a, 712b) may be a positive electrode.

[0100] For example, the first electrode (711a, 711b) can be formed by coating a positive active material onto an aluminum (Al) substrate to form a positive electrode. Additionally, the second electrode (712a, 712b) can be formed by coating a negative active material onto a copper (Cu) substrate to form a negative electrode.

[0101] The unwound portion (711b) of the first electrode and the unwound portion (712b) of the second electrode are respectively provided at both ends in the winding axis direction of the electrode assembly (710), but electrode terminals (741) and cases (720) having different polarities are provided together in the same direction. A vent plate (742) is located on the opposite side of the electrode terminal (741).

[0102] The case (720) 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 (720) may provide a space for accommodating the electrode assembly (710). The case (720) may have an opening on one side to allow the electrode assembly (710) to be inserted.

[0103] For example, if the secondary battery is a cylindrical secondary battery, the case (720) may be formed into a cylinder to house the electrode assembly (710). According to one embodiment of the present disclosure, the diameter of the case (720) may be 40 mm to 50 mm. For the purpose of explaining the invention, the secondary battery in FIG. 7 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.

[0104] The electrode terminal (741) and the vent plate (742) may be provided at each axial end of the case (720) so as to face each other. The vent plate (742) may be coupled to seal the opening of the case (720) after the electrode assembly (710) is inserted into the case (720).

[0105] Specifically, the vent plate (742) is configured to cover the opening of the case (720) 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 contacted area to an external component (e.g., an external terminal) to electrically connect the secondary battery cell.

[0106] In FIG. 7, the vent cap plate (742) is shown positioned on the upper part of the secondary battery and the electrode terminal (741) 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 cap plate (742) and the electrode terminal (741) may be changed to be positioned on the lower part and the upper part of the secondary battery, respectively.

[0107] The electrode terminal (741) is connected to the first electrode (711a, 711b) via the first current collector plate (730) through a rivet (743), and the case (720) is connected to the second electrode (712a, 712b) via the second current collector plate (750). At this time, the vent plate (742) is electrically separated from the second current collector plate (750) and the case (720) and does not have polarity.

[0108] An electrode terminal (741) connected to the first electrode (711a, 711b) of the electrode assembly (710) inserted into the case (720) from the outside is installed on one side of the case. The case (720) has a through hole (721) that is partially open on one side.

[0109] For example, the electrode terminal (741) may be installed in a through hole (721) of the case (720) in a rivet structure. To this end, the electrode terminal (741) may be connected to a rivet (743). One end of the rivet (743) is welded to the first current collector plate (730) and positioned to pass through the through hole (721). The electrode terminal (741) is connected to the rivet (743) and positioned on the outside of the case (720). The electrode terminal (741) may be formed to protrude above the outer surface of the case (720) around the through hole (721) and used as an anode terminal. At this time, the first current collector plate (730) becomes an anode current collector plate.

[0110] At this time, the first current collector plate (730) is electrically connected to the unoccupied portion (711b) of the first electrode through a rivet (743) and is electrically and mechanically connected to the electrode terminal (741). The first current collector plate (730) is electrically connected to the electrode terminal (741) in a structure that reduces resistance by contacting most of the unoccupied portion (711b) of the first electrode. The rivet (743) included in the electrode terminal (741) is installed in a state of electrical insulation from the case (720) while forming a hermetic structure against the electrolyte by interposing an insulator (723) in the through hole (721).

[0111] Here, the insulator (723) may be made of a polymer comprising ethylene propylene rubber (EPDM), polypropylene (PP), polyimide (PI), polyethylene terephthalate (PET), polycarbonate (PC), or any combination thereof.

[0112] As another example, the insulator (723) 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 (723) is not limited to the materials listed above and may include various materials with excellent plasticity and insulation properties depending on the choice.

[0113] In one embodiment, the first current collector plate (730) may include a metal plate (731) comprising at least one bridge (732). For example, the first current collector plate (730) 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 (731) and the bridge (732) constituting the first current collector plate (730) may all be made of the same material to form a single unit.

[0114] Here, the bridge (732) of the first collector plate (730) can be configured to break when a current exceeding a set value flows. For example, the bridge (732) 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.

[0115] An insulating tape (745) may be attached to one side of the first current collector plate (730). The insulating tape (745) may be interposed between the first current collector plate (730) and the case (720) or between the uninsulated portion (711b) of the first electrode and the case (720) to perform the function of electrically insulating each component. In one embodiment, the central portion of the insulating tape (745) may include a perforation (746) corresponding to the shape of a rivet (743) so that the rivet (743) can come into contact with the first current collector plate (730). Additionally, the insulating tape (745) may include a side wall (747) to wrap around a part of the electrode assembly (710).

[0116] Additionally, the case (720) has a fully open opening (722) to allow the electrode assembly (710) to be inserted on the other side. The vent plate (742) seals the opening (722) after the electrode assembly (710) is inserted into the case (720) and is electrically separated from the case (720).

[0117] At this time, the second current collector plate (750) is electrically connected to the non-electrical portion (712b) of the second electrode and is electrically connected to the case (720). The second current collector plate (750) is connected to the case (720) in a structure that reduces resistance by contacting most of the non-electrical portion (712b) of the second electrode.

[0118] The second current collector plate (750) includes a bottom portion (751) welded to the non-bonded portion (712b) of the second electrode and a wing portion (752) formed adjacent to the bottom portion (751) and welded to the beading portion (729). The second current collector plate (750) is formed by cutting and bending a circular plate, and is provided with a plurality of bottom portions (751) and wing portions (752), respectively, and is arranged alternately with one another along the circumferential direction. In one embodiment, the wing portion (752) can repeatedly form an axial (upward) bend and a radial (outer) bend of the electrode assembly (710).

[0119] In one embodiment, when the uncoated portion (712b) of the second electrode and the bottom portion (751) of the second current collector plate (750) are welded, the bottom portion (751) can form a weld line in the diameter direction of the second current collector plate (750). Thus, the bottom portion (751) can be evenly connected along the circumferential direction in the area of ​​the uncoated portion (712b) of the second electrode, and the wing portion (752) can be evenly connected along the circumferential direction in the area of ​​the beading portion (729). This enables a uniform current flow along the circumferential direction from the uncoated portion (712b) of the second electrode to the entire area of ​​the beading portion (729) of the case (720).

[0120] Additionally, the second collector plate (750) is provided with a hole (753) in the center, so it can absorb and mitigate deformation caused by welding between the bottom part (751) and the non-welded part (712b) of the second electrode, as well as vibrations and shocks that may be transmitted between the wing part (752) and the bottom part (751). The hole (753) may have a size within a range that can absorb vibrations and shocks without increasing current resistance between the wing part (752) and the bottom part (751).

[0121] The vent plate (742) is electrically separated from the second current collector plate (750) and installed in the opening (722) of the case (720) by a clamping process. Alternatively, the vent plate (742) is installed in the opening (722) of the case (720) by a welding process. Due to the connection of the second current collector plate (750), the case (720) can be used as a negative terminal. At this time, the second current collector plate (750) becomes a negative current collector plate.

[0122] The vent plate (742) may have a notch (744) formed on its inner surface. The notch (744) 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 (744) is designed to be easily cut open by receiving concentrated internal pressure during an abnormal event. The notch (744) may be formed over the entire area along the circumferential direction of the vent plate (742), or it may be formed in multiple locations spaced apart at set intervals.

[0123] The gasket (760) is interposed between the second current collector plate (750) and the vent plate (742) and between the second current collector plate (730) and the case (720), and acts as a seal through the beading portion (729) or clamping process. Additionally, the gasket (760) can form an airtight structure against the electrolyte between the second current collector plate (730) and the opening (722) of the case (720).

[0124] For example, the gasket (760) 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.

[0125] The sealing tape (790) can be attached to wrap the outer surface of the jelly roll of the electrode assembly (710) at least once. Additionally, the electrode assembly (710) is inserted into the case (720) with the sealing tape (790) attached, and the sealing tape (790) can be positioned between the electrode assembly (710) and the case (720). Thus, the secondary battery assembled is prevented from moving the electrode assembly (710) up and down or forward and backward within the case (720), thereby preventing the separation of terminals or damage to the components, and even when the electrode assembly (710) expands due to charging and discharging, cracks in the case (720) or the electrode assembly (710) caused by excessive expansion of the electrode assembly (710) can be suppressed.

[0126] 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.

[0127] FIG. 8 is a drawing showing the surface of the substrate layer of a first electrode that has been ultrasonically welded according to one embodiment of the present disclosure.

[0128] According to one embodiment of the present disclosure, the unbonded portion of the substrate layer and the first reinforcing material may be joined by welding. Specifically, the first reinforcing material may be attached to at least a portion of the first unbonded portion 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 those skilled in the art.

[0129] In one embodiment, in order to increase the energy density of the secondary battery, ultrasonic welding can be used when the thickness of the first reinforcing substrate or the substrate layer is thin, thereby minimizing damage to the first reinforcing substrate or the substrate layer. In drawings (810, 820, 830) showing the substrate layer blank portion of the first electrode or the surface of the first reinforcing substrate that has been ultrasonically welded, it can be seen that rough irregularities are formed after welding.

[0130] According to some embodiments of the present disclosure, friction is generated by these rough irregularities, and a short circuit may occur due to the expansion of the anode or cathode during the charging and discharging of the electrode assembly. Therefore, the occurrence of a short circuit can be prevented by coating an insulating coating layer on the reinforcing material.

[0131] FIG. 9 is a flowchart illustrating an example of a method for manufacturing an electrode assembly according to the present disclosure.

[0132] A method (900) for manufacturing an electrode assembly according to one embodiment of the present disclosure may be disclosed by providing a substrate layer comprising a conductor (S910). According to one embodiment of the present disclosure, the substrate layer may include a film layer made of an insulating material, a first metal layer coated on one side of the film layer, and a second metal layer coated on the other side of the film layer so as to face the first metal layer.

[0133] Afterwards, a first reinforcing material can be attached to the uninsulated portion of the substrate layer (S920). Here, the width of the uninsulated portion of the substrate layer may be greater than or equal to the width of the first insulating coating layer. Specifically, the width of the uninsulated portion of the substrate layer may be 4% to 6% of the width of the substrate layer.

[0134] In one embodiment, the step (S920) of bonding a first reinforcing material to an unbonded portion of a substrate layer may include the step of bonding a first reinforcing material to an unbonded portion of a first metal layer. The step (S920) of bonding a first reinforcing material to an unbonded portion of a substrate layer may include the step of bonding the unbonded portion and the first reinforcing material by ultrasonic welding.

[0135] After that, a first insulating coating layer can be formed on a first reinforcing substrate corresponding to the uninsulated portion (S930). The first insulating coating layer may include polyethylene, polypropylene, polyetherimide, polyacetal, polysulfone, polyetheretherketone, polyester, polyamide, ethylene-vinyl acetate copolymer, polystyrene, polytetrafluoroethylene, polysiloxane, polyimide, or any combination thereof.

[0136] According to one embodiment, the step (S930) of forming a first insulating coating layer on a first reinforcing substrate may include forming the end of the first insulating coating layer facing the composite layer so as to be perpendicular to the substrate layer.

[0137] A method for manufacturing an electrode assembly (900) according to one embodiment may further include the steps of bonding a second reinforcing material to a second metal layer and forming a second insulating coating layer on the second reinforcing material.

[0138] Next, a first electrode can be manufactured by forming a composite layer on a part of the substrate layer (S940). According to one embodiment, the step of manufacturing the first electrode (S940) may include the step of forming one end of the composite layer to be in contact with the first insulating coating layer. The one end of the composite layer in contact with the first insulating coating layer may be perpendicular to the substrate layer. Additionally, according to one embodiment, a part of the first insulating coating layer may be interposed between the composite layer and the first reinforcing substrate.

[0139] Subsequently, the first electrode, the separator, and the second electrode can be stacked (S950). Additionally, the stacked first electrode, the separator, and the second electrode can be wound to manufacture an electrode assembly.

[0140] A method for manufacturing an electrode assembly (900) according to one embodiment may further include the step of bending a first reinforcing member so as to be electrically connected to a second reinforcing member. Specifically, the first reinforcing member may be bent toward the core portion of the wound electrode assembly.

[0141] 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, A separator stacked on the first electrode, and A second electrode stacked on the separator above Includes, The first electrode above is, A substrate layer including a conductor, a composite layer formed on the substrate layer, a first reinforcing material bonded to an unbonded portion of the substrate layer, and a first insulating coating layer formed on the first reinforcing material, An electrode assembly in which at least a portion of the overlapping portion between the first reinforcing material and the first insulating coating layer is located on the uninsulated portion.

2. In Paragraph 1, The above substrate layer is, Film layer made of insulating material, A first metal layer coated on one surface of the above film layer, and A second metal layer coated on the other side of the film layer so as to face the first metal layer, Includes, The above first reinforcing material is an electrode assembly that is coupled to the uncoated portion of the above first metal layer.

3. In Paragraph 2, A second reinforcing material bonded to the second metal layer, and An electrode assembly further comprising a second insulating coating layer formed on the second reinforcing substrate.

4. In Paragraph 3, The first reinforcing member is an electrode assembly that is bent to be electrically connected to the second reinforcing member.

5. In Paragraph 1, An electrode assembly in which the width of the unworn portion of the above-mentioned substrate layer is greater than or equal to the width of the overlapping portion between the first reinforcing substrate and the first insulating coating layer.

6. In Paragraph 1, An electrode assembly in which the width of the unworn portion of the substrate layer is 4% to 6% of the width of the substrate layer.

7. In Paragraph 1, An electrode assembly in which the unbonded portion of the above-mentioned substrate layer and the above-mentioned first reinforcing substrate are joined by ultrasonic welding.

8. In Paragraph 1, The first insulating coating layer comprises polyethylene, polypropylene, polyetherimide, polyacetal, polysulfone, polyetheretherketone, polyester, polyamide, ethylene-vinyl acetate copolymer, polystyrene, polytetrafluoroethylene, polysiloxane, polyimide, or any combination thereof, forming an electrode assembly.

9. In Paragraph 1, One end of the above composite layer is in contact with the first insulating coating layer, forming an electrode assembly.

10. In Paragraph 9, An electrode assembly in which one end of the composite layer in contact with the first insulating coating layer is perpendicular to the substrate layer.

11. In Paragraph 9, A portion of the first insulating coating layer is an electrode assembly interposed between the composite layer and the first reinforcing substrate.

12. A step of providing a substrate layer including a conductor, A step of combining a first reinforcing material to the unincorporated portion of the above-mentioned substrate layer, A step of forming a first insulating coating layer on the first reinforcing substrate, A step of manufacturing a first electrode by forming a composite layer on a part of the above substrate layer, and Step of stacking the first electrode, separator, and second electrode, Includes, A method for manufacturing an electrode assembly in which at least a portion of the overlapping portion between the first reinforcing material and the first insulating coating layer is located on the uninsulated portion.

13. In Paragraph 12, The above substrate layer Film layer made of insulating material, A first metal layer coated on one surface of the above film layer, and A second metal layer coated on the other side of the film layer so as to face the first metal layer, Includes, A method for manufacturing an electrode assembly, wherein the step of bonding a first reinforcing material to a non-bonded portion of the above-mentioned substrate layer comprises the step of bonding the first reinforcing material to a non-bonded portion of the above-mentioned first metal layer.

14. In Paragraph 13, A step of bonding a second reinforcing material to the second metal layer, and Step of forming a second insulating coating layer on the second reinforcing material A method for manufacturing an electrode assembly, further comprising 15. In Paragraph 14, A step of bending the first reinforcing member so as to be electrically connected to the second reinforcing member. A method for manufacturing an electrode assembly, further comprising 16. In Paragraph 12, The step of combining a first reinforcing material to the unincorporated portion of the above-mentioned substrate layer is, A method for manufacturing an electrode assembly comprising the step of joining the above-mentioned non-reinforcing portion and the above-mentioned first reinforcing material by ultrasonic welding.

17. In Paragraph 12, The step of manufacturing the first electrode above is, A method for manufacturing an electrode assembly comprising the step of forming one end of the above composite layer to be in contact with the first insulating coating layer.

18. In Paragraph 12, The step of forming a first insulating coating layer on the first reinforcing substrate is: A method for manufacturing an electrode assembly, comprising the step of forming the end of the first insulating coating layer facing the composite layer so as to be perpendicular to the substrate layer.

19. An electrode assembly formed by stacking a first electrode, a separator, and a second electrode, Electrolytes, and A case accommodating the above electrode assembly Includes, The first electrode above is, A substrate layer including a conductor, A composite layer formed on the above substrate layer, A first reinforcing material coupled to the uncoordinated portion of the substrate layer, and It includes a first insulating coating layer formed on the first reinforcing material, and A secondary battery in which at least a portion of the overlapping portion between the first reinforcing material and the first insulating coating layer is located on the uninsulated portion.

20. In Paragraph 19, The electrode assembly is formed by winding the stacked first electrode, the separator, and the second electrode, and The above first reinforcing material is a secondary battery that is bent toward the core portion of the electrode assembly.

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