Secondary battery and method for manufacturing secondary battery

Abstract

The present disclosure provides a secondary battery and a method for manufacturing the secondary battery. The secondary battery, according to the present disclosure, comprises: an electrode assembly formed by stacking a first electrode, a separator, and a second electrode; a case accommodating the electrode assembly; a vent plate sealing an opening at one side of the case; and a first current collecting plate interposed between the electrode assembly and the vent plate, wherein the first electrode includes: a first active material layer portion in which a first active material is coated on a first substrate; a first uncoated portion in which the first substrate is exposed; and a first reinforcing substrate attached to at least a part of the first uncoated portion, and the first current collecting plate may be joined to a leading end of the first electrode.

Description

Secondary battery and method for manufacturing a secondary battery

[0001] The present disclosure relates to a secondary battery and a method for manufacturing a secondary battery.

[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] In order for ions to move smoothly within the battery and transfer electrical energy during the charging and discharging processes, the electrode assembly of the secondary battery must be sufficiently impregnated with the electrolyte. However, as the size of the electrode assembly increases to enhance energy density, the movement of the electrolyte becomes less efficient and takes a long time to impregnate, resulting in defects where the electrolyte is not impregnated within the electrode assembly. The presence of such unimpregnated areas shortens the battery's lifespan and leads to reduced battery performance due to energy loss and safety accidents. Therefore, it is necessary to secure means to enhance the safety of the electrode assembly to address this issue.

[0005] 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.

[0006] The problem that the present invention aims to solve is to provide a secondary battery and a method for manufacturing a secondary battery to solve the above technical problem.

[0007] 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.

[0008] A secondary battery according to an embodiment of the present invention for solving the above technical problem comprises an electrode assembly formed by stacking a first electrode, a separator, and a second electrode, a case for housing the electrode assembly, a vent plate for sealing an opening on one side of the case, and a first current collector plate interposed between the electrode assembly and the vent plate, wherein the first electrode comprises a first composite portion in which a first active material is coated on a first substrate, a first uncoated portion in which the first substrate is exposed at the tip of the first electrode, and a first reinforcing material attached to at least a part of the first uncoated portion, and the first current collector plate may be joined to the tip of the first electrode.

[0009] According to one embodiment of the present disclosure, the first composite part and the first non-composite part may be parallel to each other.

[0010] According to one embodiment of the present disclosure, the tip of the first electrode may include at least a portion of the first non-reinforcing portion or the first reinforcing material.

[0011] According to one embodiment of the present disclosure, the thickness of the tip of the first electrode joined to the first current collector plate may be 20 μm to 30 μm.

[0012] According to one embodiment of the present disclosure, the first reinforcing material may be attached to at least a portion of the first unincorporated portion by ultrasonic welding.

[0013] According to one embodiment of the present disclosure, the length of the first reinforcing material may be 70% to 100% of the length of the first unincorporated portion.

[0014] According to one embodiment of the present disclosure, the first reinforcing material may be attached to at least one side of the first unincorporated portion.

[0015] According to one embodiment of the present disclosure, the first reinforcing material may be of the same material as the first material.

[0016] According to one embodiment of the present disclosure, the length of the first unworn portion may be 1% to 5% of the length of the first composite portion.

[0017] According to one embodiment of the present disclosure, an electrode assembly is formed by winding a first electrode, a separator, and a second electrode, and a first unwound portion and a first reinforcing material may be disposed in the wound core portion of the electrode assembly.

[0018] According to one embodiment of the present disclosure, the second electrode comprises a second composite portion in which a second active material is coated on a second substrate, a second uncoated portion in which the second substrate is exposed, and a second reinforcing material attached to the second uncoated portion, and the secondary battery according to one embodiment of the present disclosure may further comprise a second current collector plate joined to the second uncoated portion or the second reinforcing material.

[0019] According to one embodiment of the present disclosure, a second current collector plate may be arranged to face a first current collector plate with an electrode assembly in between inside a case.

[0020] According to one embodiment of the present disclosure, an electrode assembly housed inside a case may be impregnated with an electrolyte.

[0021] A method for manufacturing a secondary battery according to one embodiment of the present disclosure for solving a technical problem comprises the steps of: forming an electrode assembly by stacking a first electrode, a separator, and a second electrode; inserting the electrode assembly through an opening on one side of a case; arranging a first current collector plate to be joined to the tip of the first electrode on one side of the electrode assembly; and sealing the opening on the case with a vent plate. The first electrode may include a first composite portion in which a first active material is coated on a first substrate, a first uncoated portion in which the first substrate is exposed at the tip of the first electrode, and a first reinforcing material attached to at least a portion of the first uncoated portion.

[0022] According to one embodiment of the present disclosure, the step of arranging a first current collector plate to be joined to the tip of a first electrode on one side of an electrode assembly may include the step of arranging the first current collector plate so that the tip of the first electrode and the first current collector plate are joined vertically.

[0023] According to one embodiment of the present disclosure, the step of forming an electrode assembly may include the step of attaching a first reinforcing material to at least a portion of a first unincorporated portion by ultrasonic welding.

[0024] According to one embodiment of the present disclosure, the step of forming an electrode assembly may include the step of attaching a first reinforcing material to at least one side of a first unincorporated portion.

[0025] According to one embodiment of the present disclosure, the step of forming an electrode assembly includes the step of winding a stacked first electrode, a separator, and a second electrode, and the first unwound portion and the first reinforcing material may be disposed in the winding core portion of the electrode assembly.

[0026] A method for manufacturing a secondary battery according to one embodiment of the present disclosure may further include the step of injecting an electrolyte into a case.

[0027] According to some embodiments of the present disclosure, an electrode including a reinforcing material can advantageously secure welding (joining) conditions of a current collector plate due to the reinforcing material attached to the unsupported portion of an electrode assembly, and can support the material so that the tip of the electrode is not bent when the electrolyte is injected into the case.

[0028] According to some embodiments of the present disclosure, the electrolyte can move smoothly between the electrode and the separator of the electrode assembly, thereby preventing defects in the secondary battery caused by unimpregnated portions of the electrolyte in the electrode assembly.

[0029] According to some embodiments of the present disclosure, the occurrence of unimpregnated portions of the electrolyte in an electrode assembly can be prevented to increase the lifespan of a secondary battery and to suppress energy loss, reduced battery performance, and safety accidents caused by lithium precipitation.

[0030] 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.

[0031] 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.

[0032] FIG. 1 is a schematic diagram illustrating a secondary battery according to one embodiment of the present disclosure.

[0033] FIG. 2 is a plan view showing the appearance of an electrode assembly according to one embodiment of the present disclosure when viewed in the direction of the winding axis.

[0034] FIG. 3 is a plan view showing a first electrode of a secondary battery according to one embodiment of the present disclosure.

[0035] FIG. 4 is a drawing illustrating a first electrode of a secondary battery according to one embodiment of the present disclosure.

[0036] FIG. 5 is a diagram illustrating the process of injecting an electrolyte into a secondary battery according to one embodiment of the present disclosure.

[0037] FIG. 6 is a cross-sectional view of an electrode assembly and a current collector plate according to one embodiment of the present disclosure.

[0038] FIG. 7 is a cross-sectional view of a secondary battery according to one embodiment of the present disclosure.

[0039] FIG. 8 is a flowchart illustrating an example of a method for manufacturing a secondary battery according to the present disclosure.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] The terms used in this specification are intended to describe embodiments of the present disclosure and are not intended to limit the present disclosure.

[0053] FIG. 1 is a schematic diagram illustrating a secondary battery according to one embodiment of the present disclosure. FIG. 2 is a plan view showing the appearance of an electrode assembly according to one embodiment of the present disclosure when viewed in the direction of the winding axis.

[0054] Referring to FIGS. 1 and 2, a secondary battery (100) according to one embodiment of the present invention may include an electrode assembly (102) formed by stacking a first electrode (110), a separator (130), and a second electrode (120), a case (140) that accommodates the electrode assembly (102), a vent plate (160) that seals an opening (142) on one side of the case (140), and a first current collector plate (150) interposed between the electrode assembly (102) and the vent plate (160).

[0055] Specifically, the electrode assembly (102) can be formed into a jelly roll state by sequentially winding the first electrode (110), the separator (130), and the second electrode (120). 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).

[0056] The electrode assembly (102) housed inside the case (140) may be impregnated with an electrolyte (not shown). Here, the electrolyte may be, for example, a liquid electrolyte, a solid electrolyte, a gel electrolyte, or a combination thereof.

[0057] In one embodiment, the electrolyte may be an organic electrolyte. The organic electrolyte may be prepared by dissolving a lithium salt in an organic solvent. For example, the organic solvent may include propylene carbonate, ethylene carbonate, fluoroethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl isopropyl carbonate, dipropyl carbonate, dibutyl carbonate, benzonitrile, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, γ-butyrolactone, dioxolane, 4-methyldioxolane, N,N-dimethylformamide, dimethylacetamide, dimethyl sulfoxide, dioxane, 1,2-dimethoxyethane, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, diethylene glycol, dimethyl ether, or a mixture thereof. Organic solvents are not limited to the types of solvents listed above, and any organic solvent used in the relevant technical field is acceptable at the choice of a person skilled in the art.

[0058] For example, lithium salts include LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, Li(CF3SO2)2N, LiC4F9SO3, LiAlO2, LiAlCl4, and LiN(C x F 2x+1 SO2)(C y F 2y+1 It may include SO2)(1≤x≤20, 1≤y≤20), LiCl, LiI, or mixtures thereof. The lithium salt is not limited to the types of salts listed above, and any that are used as lithium salts in the relevant technical field are acceptable. In one embodiment, the concentration of the lithium salt may be 0.01 M to 5.0 M.

[0059] The first electrode (110) may be an electrode corresponding to the positive or negative electrode in the electrode assembly (102). 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, when the first electrode (110) is an anode, the first substrate (112) may be formed of a metal foil such as aluminum or an aluminum alloy. In another embodiment, when the first electrode (110) is a cathode, the first substrate (112) may be formed of a metal foil such as copper, a copper alloy, nickel, or a nickel alloy.

[0061] In one embodiment, when the second electrode (120) is an anode, the second substrate (122) may be formed of a metal foil such as aluminum or an aluminum alloy. In another embodiment, when the second electrode (120) is a cathode, the second substrate (122) may be formed of a metal foil such as copper, a copper alloy, nickel, or a nickel alloy.

[0062] The materials of the first substrate (112) and the second substrate (122) are not limited to the materials listed above and may correspond to any one of the conductive metal materials used in the industry. In addition, in one embodiment, the first substrate (112) and the second substrate (122) may be composed of different materials.

[0063] In one embodiment, the first electrode (110) included in the electrode assembly (102) may include a first composite portion (110_1) on which a first active material (114) is applied to a first substrate (112). Specifically, the first active material (114) may be applied to one side or both sides of the first substrate (112), which is formed as a thin metal plate in the first composite portion (110_1). The method of applying the first active material (114) is not limited to dry or wet methods, and may be applied together with a binder that facilitates the electrodeposition of the first active material (114) on the first substrate (112).

[0064] In one embodiment, the first electrode (110) included in the electrode assembly (102) may include a first uncoated portion (110_2) in which a portion of the first substrate (112) is exposed because the first active material (114) is not coated thereon. Here, the first uncoated portion (110_2) may be located at the tip (118) of the first electrode (110).

[0065] In one embodiment, the first electrode (110) may include a first reinforcing material (116) attached to at least a portion of the first unincorporated portion (110_2). Specifically, the first reinforcing material (116) may be attached to at least one side of the first unincorporated portion (110_2). For example, as shown in FIGS. 1 and 2, the first reinforcing material (116) may be attached to opposite sides of the first unincorporated portion (110_2).

[0066] The length of the first reinforcing member (116) may be smaller than or equal to the length of the first unincorporated portion (110_2). Specifically, the first reinforcing member (116) may be attached to at least one side of the first unincorporated portion (110_2) such that one end of the first reinforcing member (116) and one end of the first unincorporated portion (110_2) form a single plane. The one end of the first reinforcing member (116) and the one end of the first unincorporated portion (110_2) thus attached may form the tip (118) of the first electrode (110). That is, in one embodiment, the tip (118) of the first electrode (110) may include at least a portion of the first unincorporated portion (110_2) or the first reinforcing member (116).

[0067] According to one embodiment, the first composite portion (110_1) and the first uncoordinated portion (110_2) may be parallel to each other. Specifically, the first substrate (112) that commonly constitutes the first composite portion (110_1) and the first uncoordinated portion (110_2) may be a single flat metal plate that is not bent. Through this, the first reinforcing substrate (116) does not close the space between the first electrode (110) and the separator (130). Therefore, an electrolyte (not shown) that impregnates the electrode assembly into the case (140) can be injected and move smoothly into the space between the first electrode (110) and the separator (130).

[0068] According to some embodiments of the present disclosure, the electrolyte (or electrolyte solution) can be smoothly moved between the first electrode (110) and the separator (130) of the electrode assembly (102) to prevent defects in the secondary battery (100) caused by the unimpregnated portion of the electrolyte in the electrode assembly (102).

[0069] In one embodiment, the first current collector plate (150) may be joined to the tip (118) of the first electrode. Here, the first current collector plate (150) may be composed of a metal plate. For example, the first current collector plate (150) may be a disc-shaped plate 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 a combination thereof (alloy). The tip (118) of the first electrode may be joined to the lower surface of the metal plate constituting the first current collector plate (150). Specifically, the surface of the tip (118), which consists of one end of the first reinforcing member (116) and one end of the first unincorporated portion (110_2), may be joined to the lower surface of the metal plate. The method of joining is not limited to a specific type, and various methods generally used for attaching two materials may be used according to the choice of a person skilled in the art. In order to secure a bonding surface with the first current collector plate (150), the thickness of the tip (118) of the first electrode can be set to 20 μm to 30 μm. This will be described later in FIGS. 3 and FIGS. 4.

[0070] The first reinforcing material (116) may be attached to at least a portion of the first unbonded portion (110_2) using any one of the following methods: ultrasonic welding, laser welding, resistance welding, TIG welding (Tungsten Inert Gas Welding), or a 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. However, in order to increase the energy density of the secondary battery (100), if the thickness of the first reinforcing material (116) or the first material (112) is thin, ranging from 5 μm to 15 μm, ultrasonic welding may be used to minimize damage to the first reinforcing material (116) or the first material (112).

[0071] According to one embodiment, the first reinforcing material (116) may be of the same material as the first material (112). For example, when the first electrode (110) is an anode, the first reinforcing material (116) may be formed of a metal foil 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 foil such as copper, a copper alloy, nickel, or a nickel alloy.

[0072] According to one embodiment, the second electrode (120) may include a second substrate (122) and a second active material (124). To prevent the occurrence of a short circuit, the second electrode (120) may be spaced apart from the first current collector plate (150). The specific configuration of the second electrode (120) will be described later in FIG. 6.

[0073] FIG. 3 is a plan view showing a first electrode of a secondary battery according to one embodiment of the present disclosure. FIG. 4 is also a drawing illustrating a first electrode of a secondary battery according to one embodiment of the present disclosure.

[0074] Referring to FIGS. 3 and 4, the first electrode (110) may include a first composite portion (110_1) in which a first active material (114) is applied to a first substrate (112), and a first uncoated portion (110_2) in which a portion of the first substrate (112) is exposed because the first active material (114) is not applied. Specifically, the first active material (114) may be applied to one side or both sides of the first substrate (112), which is formed as a thin metal plate, in the first composite portion (110_1) of the first electrode (110).

[0075] In one embodiment, the first electrode (110) may include a first reinforcing material (116) attached to at least a portion of the first unlined portion (110_2). In this case, the length (h2) of the first reinforcing material (116) may be smaller than or equal to the length (h1) of the first unlined portion (110_2). Specifically, the length (h2) of the first reinforcing material (116) may be 70% to 100% of the length (h1) of the first unlined portion (110_2). Additionally, in one embodiment, the length (h2) of the first unlined portion (110_2) may be 1% to 5% of the length (h3) of the first composite portion (110_1).

[0076] The first reinforcing member (116) may be attached to at least one side of the first unsupported portion (110_2) such that one end of the first reinforcing member (116) and one end of the first unsupported portion (110_2) form a single plane at the tip (118) of the first electrode (110). For example, as shown in FIGS. 3 and 4, the first reinforcing member (116) may be attached to both opposing sides of the first unsupported portion (110_2).

[0077] According to one embodiment, in order to secure a bonding surface with the first current collector plate (150 in FIG. 1), the thickness (d) of the tip (118) of the first electrode (110) may be set to 20 μm to 30 μm. For example, the thickness (d) of the tip (118) of the first electrode (110) may be 21 μm to 30 μm, 24 μm to 30 μm, or 24 μm to 27 μm. In one embodiment, the first reinforcing material (116) may have the same material and thickness as the first material (112).

[0078] According to some embodiments of the present disclosure, when the thickness (d) of the tip (118) of the first electrode (110) is 20 μm to 30 μm, the welding (joining) conditions of the first current collector plate can be advantageously secured due to the reinforcing material (116) attached to the first uncoated portion (110_2). At the same time, when the electrolyte is injected into the case, the reinforcing material (116) can facilitate the flow of the electrolyte so that the electrolyte is impregnated into the first composite portion (110_1) while supporting the first substrate (112) so that the tip (118) of the first electrode (110) is not bent.

[0079] Other details regarding the configuration are as described above with reference to FIGS. 1 and FIGS. 2.

[0080] FIG. 5 is a diagram illustrating the process of injecting an electrolyte into a secondary battery according to one embodiment of the present disclosure.

[0081] Referring to FIG. 5, a secondary battery (500) according to one embodiment of the present invention may include an electrode assembly (510) including a reinforcing material (512) and a case (540) that accommodates the electrode assembly (510). During the process of manufacturing the secondary battery (500), an electrolyte (520) may be injected through an opening (542) on one side of the case (540). In one embodiment, to prevent deformation of the electrode assembly (510) that may occur as the electrolyte (520) is injected at high pressure, the reinforcing material (512) may be attached to the opening (542) side of the electrode assembly (510).

[0082] As the electrolyte (520) is injected, the electrode assembly (510) can be divided into an electrolyte-impregnated area (514) and an electrolyte-unimpregnated area (516). The injected electrolyte (520) can impregnate the electrode assembly (510) by gradually moving (522) from both ends of the electrode assembly (510) toward the center.

[0083] According to some embodiments of the present disclosure, a reinforcing material (512) is attached to the unimpregnated portion of the electrode, and the unimpregnated portion of the electrode and the composite portion of the electrode are parallel to each other to facilitate the movement (522) of the electrolyte (520). By doing so, the occurrence of an electrolyte-unimpregnated region (516) in the electrode assembly (510) is prevented, thereby increasing the lifespan of the secondary battery (500) and suppressing energy loss due to lithium precipitation, reduced battery performance, and safety accidents.

[0084] FIG. 6 is a cross-sectional view of an electrode assembly and a current collector plate according to one embodiment of the present disclosure.

[0085] Referring to FIG. 6, an electrode assembly (600) according to one embodiment of the present invention may be formed by winding a first electrode (610), a separator (630), and a second electrode (620). Specifically, the electrode assembly (600) may be formed in a jelly roll state by sequentially winding the first electrode (610), the separator (630), and the second electrode (620).

[0086] At this time, the first unwound portion (610_2) and the first reinforcing material (616) of the first electrode (610) may be placed in the core portion of the electrode assembly (600). Specifically, since the first composite portion (610_1) and the first unwound portion (610_2) are parallel to each other, even if they are placed in the core portion of the electrode assembly (600), there may be a low possibility of a short circuit occurring with the second electrode during the charging and discharging of the secondary battery. Through this, the secondary battery according to some embodiments of the present invention may have a high energy density.

[0087] According to one embodiment, the second electrode (620) may include a configuration corresponding to the configuration of the first electrode (110) described above with reference to FIG. 1. Specifically, the second electrode (620) may include a second composite portion (620_1) on which a second active material (624) is coated on a second substrate (622), a second uncoated portion (620_2) on which the second substrate (622) is exposed, and a second reinforcing substrate (626) attached to the second uncoated portion (620_2).

[0088] An electrode assembly (600) according to one embodiment of the present disclosure may be connected to a first current collector plate (652) and a second current collector plate (654). Here, the first current collector plate (652) and the first current collector plate (654) may be composed of metal plates.

[0089] Specifically, the first current collector plate (652) may be joined to the tip of the first electrode (610), and the second current collector plate (654) may be joined to the tip of the second electrode (620). For example, the second current collector plate (654) may be joined to a part of the second substrate (622) or the second reinforcing substrate (626) located at one end of the second non-reinforcing portion (620_2).

[0090] As shown in FIG. 6, the second non-removable portion (620_2) of the second electrode (620) and the first non-removable portion (610_2) of the first electrode (610) can be arranged in opposite directions. Accordingly, the second current collector plate (654) can be arranged to face the first current collector plate (652) with the electrode assembly (600) in between inside the case.

[0091] Other details regarding the configuration are as described above with reference to FIGS. 1 and FIGS. 2.

[0092] FIG. 7 is a cross-sectional view of a secondary battery according to one embodiment of the present disclosure.

[0093] 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 houses the electrode assembly (710), 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).

[0094] Here, the first electrode (711a, 711b) may have the same or similar configuration as the first electrode (110, 610) 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 (102, 510, 600) described with reference to FIGS. 1 to 6.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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).

[0099] 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.

[0100] 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 depicted in the form 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.

[0101] 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).

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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).

[0108] 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 a combination thereof.

[0109] As another example, the insulator (723) may be made of a ceramic material including epoxy resin, alumina (Al2O3), zirconia (ZrO2), aramid fiber, Nomex, or a 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.

[0110] 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 a 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.

[0111] 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.

[0112] 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).

[0113] 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).

[0114] 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.

[0115] 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).

[0116] 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).

[0117] 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).

[0118] 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.

[0119] 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.

[0120] 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).

[0121] 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.

[0122] 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.

[0123] 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.

[0124] FIG. 8 is a flowchart illustrating an example of a method for manufacturing a secondary battery according to the present disclosure.

[0125] A method (800) for manufacturing a secondary battery according to one embodiment of the present invention may be disclosed by forming an electrode assembly by stacking a first electrode, a separator, and a second electrode (S810). Additionally, according to one embodiment, the step of forming the electrode assembly (S810) may include the step of attaching a first reinforcing material to at least one side of a first uncoated portion. Specifically, the step of forming the electrode assembly (S810) may include the step of attaching a first reinforcing material to at least a portion of the first uncoated portion by ultrasonic welding.

[0126] According to one embodiment, the step of forming an electrode assembly (S810) includes the step of winding a stacked first electrode, a separator, and a second electrode, and the first unwound portion and the first reinforcing material may be disposed in the winding core portion of the electrode assembly.

[0127] Here, the first electrode may include a first composite portion in which a first active material is coated on a first substrate, a first uninsulated portion in which the first substrate is exposed at the tip of the first electrode, and a first reinforcing material attached to at least a portion of the first uninsulated portion. For example, the first electrode may have a configuration corresponding to the first electrode (110) described with reference to FIGS. 1 to 4. The electrolyte (or electrolyte solution) can move smoothly between the first electrode and the separator of the electrode assembly having such a configuration, thereby preventing defects in the secondary battery caused by the uninserted portion of the electrolyte.

[0128] After this, the electrode assembly can be inserted through an opening on one side of the case (S820).

[0129] Additionally, a first current collector plate may be positioned to be joined to the tip of the first electrode on one side of the electrode assembly (S830). The step of positioning the first current collector plate to be joined to the tip of the first electrode on one side of the electrode assembly according to one embodiment of the present disclosure (S830) may further include the step of positioning the first current collector plate so that the tip of the first electrode and the first current collector plate are joined vertically.

[0130] After this, one opening of the case can be sealed with a vent plate (S840).

[0131] A method for manufacturing a secondary battery (800) according to one embodiment may further include the step of injecting an electrolyte into a case.

[0132] In one embodiment, a first reinforcing material may be attached to the opening side of the electrode assembly to prevent deformation of the electrode assembly that may occur as the electrolyte is injected into the case at high pressure. The injected electrolyte may impregnate the electrode assembly by gradually moving from both ends of the electrode assembly toward the center. By doing so, the occurrence of areas not impregnated with electrolyte in the electrode assembly is prevented, thereby increasing the lifespan of the secondary battery and suppressing energy loss, reduced battery performance, and safety accidents caused by lithium precipitation.

[0133] 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. An electrode assembly formed by stacking a first electrode, a separator, and a second electrode; A case for housing the above electrode assembly; A vent plate sealing one side opening of the above case; and A first current collector plate interposed between the electrode assembly and the vent plate; Includes, The first electrode above is, A first composite part coated with a first active material on a first substrate; A first unprotected portion in which the first substrate is exposed at the tip of the first electrode; and A first reinforcing material attached to at least a portion of the first unincorporated portion; Includes, The above first current collector plate is joined to the tip of the above first electrode, a secondary battery.

2. In Paragraph 1, A secondary battery in which the first composite part and the first non-composite part are parallel to each other.

3. In Paragraph 1, A secondary battery in which the tip of the first electrode comprises at least a portion of the first non-reinforcing portion or the first reinforcing material.

4. In Paragraph 1, A secondary battery having a tip thickness of 20 μm to 30 μm of the first electrode joined to the first current collector plate.

5. In Paragraph 1, A secondary battery in which the first reinforcing material is attached to at least a portion of the first unincorporated portion by ultrasonic welding.

6. In Paragraph 1, A secondary battery in which the length of the first reinforcing material is 70% to 100% of the length of the first unincorporated portion.

7. In Paragraph 1, The above first reinforcing material is a secondary battery attached to at least one side of the above first non-reinforcing portion.

8. In Paragraph 1, The above-mentioned first reinforcing material is a secondary battery having the same material as the above-mentioned first material.

9. In Paragraph 1, A secondary battery in which the length of the first unworn portion is 1% to 5% of the length of the first composite portion.

10. In Paragraph 1, The electrode assembly is formed by winding the first electrode, the separator, and the second electrode, and A secondary battery in which the first non-reinforcing portion and the first reinforcing material are disposed in the core portion of the electrode assembly.

11. In Paragraph 1, The second electrode above is, A second composite part coated with a second active material on the second substrate; A second non-exposed portion in which the above-mentioned second description is exposed; and A second reinforcing material attached to the second non-reinforcing portion above; Includes, A secondary battery further comprising a second current collector plate joined to the second non-reinforcing portion or the second reinforcing material.

12. In Paragraph 11, The second current collector plate is a secondary battery arranged to face the first current collector plate with the electrode assembly in between inside the case.

13. In Paragraph 1, The electrode assembly housed inside the above case is a secondary battery impregnated with an electrolyte.

14. A step of forming an electrode assembly by stacking a first electrode, a separator, and a second electrode; A step of inserting the above electrode assembly through an opening on one side of the case; A step of arranging a first current collector plate to be joined to the tip of the first electrode on one side of the electrode assembly; and A step of sealing one side opening of the above case with a vent plate; Includes, The first electrode above is, A first composite part coated with a first active material on a first substrate; A first unprotected portion in which the first substrate is exposed at the tip of the first electrode; and A first reinforcing material attached to at least a portion of the first unincorporated portion; A method for manufacturing a secondary battery comprising 15. In Paragraph 14, The step of arranging a first current collector plate to be joined to the tip of the first electrode on one side of the electrode assembly is A step of arranging the first current collector plate so that the tip of the first electrode and the first current collector plate are vertically joined. A method for manufacturing a secondary battery comprising 16. In Paragraph 14, A method for manufacturing a secondary battery in which the first composite part and the first non-composite part are parallel to each other.

17. In Paragraph 14, The step of forming the above electrode assembly is, A method for manufacturing a secondary battery comprising the step of attaching the first reinforcing material to at least a portion of the first unincorporated portion by ultrasonic welding.

18. In Paragraph 14, The step of forming the electrode assembly above A method for manufacturing a secondary battery comprising the step of attaching the first reinforcing material to at least one side of the first non-reinforcing portion.

19. In Paragraph 14, The step of forming the electrode assembly includes the step of winding the stacked first electrode, the separator, and the second electrode. A method for manufacturing a secondary battery in which the first non-reinforcing portion and the first reinforcing material are disposed in the core portion of the electrode assembly.

20. In Paragraph 14, A method for manufacturing a secondary battery, further comprising the step of injecting an electrolyte into the above case.

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