Secondary battery comprising rivet and method for manufacturing same

Abstract

The present disclosure provides a secondary battery and a method for manufacturing same. The secondary battery according to the present disclosure may comprise: an electrode assembly in which a first electrode, a separator, and a second electrode are sequentially stacked; a case accommodating the electrode assembly and having an electrolyte injection hole formed through one side surface thereof; and a rivet for sealing the electrolyte injection hole, wherein the rivet may comprise: a body portion in contact with the outer surface of an area on the case where the electrolyte injection hole is formed, and a leg portion in contact with the inner surface of the area on the case where the electrolyte injection hole is formed.

Description

Secondary battery including rivets and method of manufacturing a secondary battery

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

[0002]

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

[0004] 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.

[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]

[0007] 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.

[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]

[0010] A secondary battery according to one embodiment of the present invention for solving technical problems comprises an electrode assembly in which a first electrode, a separator, and a second electrode are sequentially stacked, a case that accommodates the electrode assembly and has an electrolyte injection port formed on one side, and a rivet that seals the electrolyte injection port, wherein the rivet may include a body portion that contacts the outer surface of the region where the electrolyte injection port is formed on the case, and a leg portion that contacts the inner surface of the region where the electrolyte injection port is formed on the case.

[0011] According to one embodiment, the rivet may include at least two legs.

[0012] According to one embodiment, a compression point may be formed at a location where the leg portion of the rivet contacts the inner surface of the electrolyte injection port.

[0013] According to one embodiment, at least a portion of the leg portion of the rivet may include a step formed by bending it outward.

[0014] According to one embodiment, the distance between the point where the body part and the leg part are connected and the compression point may correspond to the thickness of the case.

[0015] According to one embodiment, the leg portion of the rivet may include a tapered outer surface.

[0016] According to one embodiment, the outer surface of the leg portion may include a coating layer.

[0017] According to one embodiment, the outer diameter of the leg portion may be larger than the inner diameter of the electrolyte injection port.

[0018] According to one embodiment, the thickness of the body portion of the rivet may be 0.4 mm to 0.7 mm.

[0019] According to one embodiment, a groove with a shape corresponding to the body of a rivet may be formed around the electrolyte injection port in the case.

[0020] According to one embodiment, the depth of the groove may correspond to the thickness of the body portion of the rivet.

[0021] According to one embodiment, a gasket may be interposed between the case and the rivet.

[0022] According to one embodiment, the case includes a cap plate that seals the opening of the case, and an electrolyte injection port may be formed in the cap plate.

[0023] According to one embodiment, the shape of the case may be cylindrical, having a diameter of 40 mm to 50 mm.

[0024] A method for manufacturing a secondary battery according to one embodiment of the present invention comprises the steps of: sequentially stacking a first electrode, a separator, and a second electrode to produce an electrode assembly; inserting the electrode assembly into a case having an electrolyte injection port formed on one side; injecting an electrolyte through the electrolyte injection port; and sealing the electrolyte injection port by a rivet, wherein the rivet may include a body portion that contacts the outer surface of the region where the electrolyte injection port is formed on the case, and a leg portion that contacts the inner surface of the region where the electrolyte injection port is formed on the case.

[0025] A method for manufacturing a secondary battery according to one embodiment may further include the step of inserting a leg portion of a rivet into the interior of a case through an electrolyte injection port to form a compression point between the leg portion and the inner surface of the case.

[0026] A method for manufacturing a secondary battery according to one embodiment may further include the step of sealing an opening of a case using a cap plate after the step of inserting an electrode assembly into a case.

[0027]

[0028] According to some embodiments of the present disclosure, a new shaped rivet including a leg portion is applied to seal the electrolyte injection port of a secondary battery, thereby lowering the height of the rivet placed in the electrolyte injection port and increasing the internal capacity of the secondary battery case.

[0029] According to some embodiments of the present disclosure, by using a rivet having a structure effective for sealing an electrolyte injection port after injecting an electrolyte into a secondary battery, unnecessary processes in the process of sealing the electrolyte injection port can be eliminated, and the efficiency of the entire secondary battery manufacturing process can be increased.

[0030] According to some embodiments of the present disclosure, in sealing the electrolyte injection port of a secondary battery, a new shaped rivet including a leg portion is applied to form a compression point at the lower end of the rivet to improve the sealing force.

[0031] According to some embodiments of the present disclosure, by simplifying the structure of a rivet that seals the electrolyte injection port of a secondary battery, the output efficiency per unit weight of the secondary battery can be increased without increasing the thickness of the case of the high-density secondary battery.

[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]

[0034] 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.

[0035] FIG. 1 is a perspective view schematically illustrating the appearance of a secondary battery according to one embodiment of the present disclosure.

[0036] FIG. 2 is a plan view showing the appearance of a rivet before joining according to one embodiment of the present disclosure.

[0037] FIG. 3 is a plan view showing the appearance of a rivet after joining according to one embodiment of the present disclosure.

[0038] FIG. 4 is a plan view showing a cross- section of a secondary battery according to one embodiment of the present disclosure.

[0039] FIG. 5 is a plan view showing a cross-section of a secondary battery according to one embodiment of the present disclosure.

[0040] FIG. 6 is a perspective view showing a rivet according to one embodiment of the present disclosure.

[0041] FIG. 7 is a cross-sectional view of a secondary battery according to one embodiment of the present disclosure.

[0042] FIG. 8 is a flowchart illustrating an example of a method for manufacturing a secondary battery according to the present disclosure.

[0043] Figure 9 is a drawing showing a method for manufacturing a secondary battery using blind rivets.

[0044]

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] The terms used in this specification are intended to describe embodiments of the present disclosure and are not intended to limit the present disclosure.

[0058] FIG. 1 is a perspective view schematically illustrating the appearance of a secondary battery according to one embodiment of the present disclosure.

[0059] Referring to FIG. 1, a secondary battery according to one embodiment of the present invention may include an electrode assembly (110) in which a first electrode, a separator, and a second electrode are sequentially stacked, a case (120) that accommodates the electrode assembly (110) and has an electrolyte injection port (122) formed on one side, and a rivet (130) that seals the electrolyte injection port (122).

[0060] The first electrode, the separator, and the second electrode may be impregnated with an electrolyte (not shown). The first electrode may be an electrode corresponding to the positive or negative electrode in a secondary battery. The second electrode may be an electrode corresponding to the opposite electrode to the first electrode. For example, if the first electrode is a positive electrode, the second electrode may be a negative electrode. Conversely, if the first electrode is a negative electrode, the second electrode may be a positive electrode.

[0061] According to one embodiment, a current collector (112) may be interposed between the electrode assembly (110) and the case (120). The current collector (112) may be electrically connected to the first electrode or the second electrode and serve as a channel for moving electrons during the charging and discharging process of the secondary battery. For example, the current collector (112) may be selected from aluminum foil, copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and combinations thereof.

[0062] According to one embodiment, a gasket (140) may be interposed between the case (120) and the rivet (130). The gasket (140) may be placed on all adjacent surfaces of the rivet (130) and the case (120) to electrically insulate the rivet (130) and the case (120). The shape of the gasket (140) will be described later in FIG. 2.

[0063] The gasket (140) may be made of an insulating material with high heat resistance to electrically insulate the case (120) and the rivet (130). For example, the gasket (140) may be made of a polymer comprising ethylene propylene rubber (EPDM), polypropylene (PP), polyimide (PI), polyethylene terephthalate (PET), polycarbonate (PC), or a combination thereof.

[0064] As another example, the gasket (140) may be made of a ceramic material including alumina (Al2O3), zirconia (ZrO2), aramid fiber, Nomex, epoxy resin, or a combination thereof. However, the material of the gasket (140) is not limited to the materials listed above, and may include various materials that are elastic and have excellent durability and heat resistance, depending on the choice of a person skilled in the art.

[0065] Additionally, a portion of the gasket (140) may be interposed between the current collector (112) and the case (120). Specifically, the gasket (140) may have a thin thickness and a shape corresponding to the shape of the current collector (112) so as to be positioned along the lower surface of the case (120) to effectively insulate the current collector (112) and the case (120). For example, if the shape of the current collector (112) is circular with a through hole in the center, the shape of the gasket (140) may also be circular with a through hole in the center and a corresponding size.

[0066] The case (120) forms the overall exterior of the secondary battery and may be formed from a conductive metal or polymer, such as aluminum, aluminum alloy, stainless steel (e.g., SUS), or nickel-plated steel. Additionally, the case (120) may provide a space for housing the electrode assembly (110). An insulating coating material may be applied to the outer or inner surface of the case (120) to a certain thickness. For the purpose of explaining the invention, the case (120) in FIG. 1 is depicted in the form of a cylindrical battery, but the scope of the present disclosure is not limited thereto and includes secondary batteries of any shape, such as prismatic batteries and pouch batteries.

[0067] The case (120) may be manufactured in a corresponding shape to accommodate the electrode assembly (110). For example, if the electrode assembly (110) is wound into a cylindrical shape, the case (120) may have a cylindrical shape. In this case, the case (120) may be manufactured to have a diameter corresponding to the diameter of the electrode assembly (110) so as to be sufficient to accommodate the electrode assembly (110). According to one embodiment, the electrode assembly (110) is wound into a cylindrical shape with a diameter of 40 mm to 50 mm, and similarly, the shape of the case (120) may be a cylindrical shape having a diameter of 40 mm to 50 mm.

[0068] In one embodiment, the case (120) may include a cap plate (121) coupled to seal the opening of the case (120). Additionally, an injection port (122) is formed in the cap plate (121), and a rivet (130) for sealing the electrolyte injection port (122) may be inserted therein. This will be described later in FIG. 7.

[0069] FIG. 2 is a plan view showing the appearance of a rivet before joining according to one embodiment of the present disclosure.

[0070] Referring to FIG. 2, the rivet (230) may include a body portion (231) that contacts the outer surface of the area where the electrolyte injection port (222) is formed on the case (220), and a leg portion (232) that penetrates the electrolyte injection port (222) on the case (220) and contacts the inner surface of the area where the electrolyte injection port (222) is formed. The body portion (231) and the leg portion (232) of the rivet (230) may be integral with each other.

[0071] The size and shape of the electrolyte injection port (222) may correspond to the size and shape of the transverse cross-section of the leg portion (232) of the rivet (230). For example, if the transverse cross-section of the leg portion (232) of the rivet (230) is in the shape of a circle with a diameter of 5 mm, the electrolyte injection port (222) located on one side of the case (220) may also be in the shape of a circle with a diameter of 5 mm. In one embodiment, if a step (234) exists in the leg portion (232) of the rivet (230), the diameter of the transverse cross-section of the leg portion (232) where the step is located may be larger than the diameter of the electrolyte injection port (222). This will be described later in FIG. 3.

[0072] According to one embodiment, a gasket (240) may be placed around the electrolyte injection port (222). Specifically, the gasket (240) may be placed or coated on the outer surface of the area surrounding the electrolyte injection port (222) in the case (220) to seal the gap between the rivet (230) and the electrolyte injection port (222).

[0073] In one embodiment, the gasket (240) surrounds the upper, side, and lower surfaces of the electrolyte injection port (222), and for this purpose, the transverse cross-section of the gasket (240) placed around the electrolyte injection port (222) may have a roughly 'C' shape. The gasket (240) may be formed or placed in various ways used in the industry, such as insert injection molding or spray coating.

[0074] According to one embodiment, at least a portion of the leg portion (232) may include a step (234) formed by being bent outward. The step (234) may protrude enough to allow insertion without breaking when the rivet (230) is inserted into the electrolyte injection port (222). Specifically, the length of the step (234) protruding from the leg portion (232) may be 0.05 mm to 0.2 mm. The thickness of the step (234) protruding from the leg portion (232) may be 0.5 mm to 0.6 mm. Although the leg portion (232) having two protruding steps (234) is shown in FIG. 2, the rivet (230) may include a leg portion (232) having at least two or more protruding steps or separated parts. This will be described later in FIG. 6.

[0075] According to one embodiment, the thickness (235) of the body portion (231) may be 0.4 mm to 1 mm. Preferably, the thickness (235) of the body portion (231) may be 0.4 mm to 0.7 mm.

[0076] According to one embodiment, a groove (224) having a shape corresponding to the body portion (231) of the rivet (230) may be formed in the case (220) around the electrolyte injection port (222). Here, the depth of the groove (224) may correspond to the thickness of the body portion (231) of the rivet (230). Through this, after joining, the upper surface of the case (220) and the upper surface of the rivet (230) may be located on the same plane.

[0077] According to some embodiments of the present disclosure, a new shape of rivet (230) including a leg portion (232) is applied to seal the electrolyte injection port (222) of a secondary battery, thereby lowering the height of the rivet (230) placed in the electrolyte injection port (222) and increasing the internal capacity of the case (220) of the secondary battery.

[0078] FIG. 3 is a plan view showing the appearance of a rivet after joining according to one embodiment of the present disclosure.

[0079] Referring to FIG. 3, a gasket (240) may be interposed between the case (220) and the rivet (230) after joining. Specifically, the gasket (240) may be positioned between the rivet (230) and the case (220) to cover a part of the body portion (231) and the leg portion (232) of the rivet (230). A part of the leg portion (232) not covered by the gasket (240) may include a step (234) that protrudes above the lower surface of the case (220).

[0080] According to one embodiment, a compression point (239) may be formed at a location where the leg portion (232) of the rivet (230) contacts the inner surface of the electrolyte injection port. Specifically, the compression point (239) may be formed at a location where the outer surface of the lower part of the gasket (240) surrounding the electrolyte injection port and the step (234) of the leg portion (232) meet each other.

[0081] According to one embodiment, the outer diameter of the leg portion may be larger than the inner diameter of the electrolyte injection port. Specifically, the diameter (236) of the transverse cross-section of the leg portion (232) where the step (234) is located may be larger than the diameter (226) of the electrolyte injection port. After the leg portion (232) of the rivet (230) is inserted into the electrolyte injection port by means of a gasket (240) and a compression point (239) interposed between the case (220) and the rivet (230), the rivet (230) can be sealed so that the inside of the case (220) is not exposed to the outside and can be fixed so that the rivet (230) does not come out.

[0082] According to some embodiments of the present disclosure, in sealing the electrolyte injection port of a secondary battery, a new shaped rivet (230) including a leg portion (232) is applied, and a compression point (239) is formed at the lower end of the rivet (230) to improve the sealing power of the case (220).

[0083] FIG. 4 is a plan view showing a cross- section of a secondary battery according to one embodiment of the present disclosure.

[0084] Referring to FIG. 4, a case (420) according to one embodiment may have the shape of a flat metal plate without a separate groove. A body part (430) coupled to the case (420) may be formed to protrude beyond one side (or upper side) of the case (420) around the electrolyte injection port and may be used as an external terminal for welding, etc.

[0085] The gasket (440) surrounds the upper, side, and lower surfaces of the electrolyte injection port penetrating the case (420), and for this purpose, the transverse cross-section of the gasket (440) placed around the electrolyte injection port may have a shape of approximately 'C'.

[0086] The upper portion of the gasket (440) covering the upper surface of the case (420) may correspond to the shape of the body portion (430) of the rivet. Specifically, the upper length of the gasket (440) may be greater than the length of the wing (435) that is not connected to the leg portion of the body portion (430) of the rivet. Specifically, the length of the wing (435) of the body portion (430) may be 0.05 mm to 2 mm. The upper length of the gasket (440) may be 0.1 mm to 2 mm. Through this, the gap between the upper surface of the case (420) and the lower surface of the body portion (430) of the rivet can be filled without gap.

[0087] The lower portion of the gasket (440) covering the lower surface of the case (420) may correspond to the shape of the step (434) of the rivet leg portion (432). Specifically, the lower length of the gasket (440) may be greater than the length of the step (434) protruding to form a compression point (439) at the rivet leg portion (432). This allows the gap between the lower surface of the case (420) and the rivet leg portion (432) to be filled without gap.

[0088] In FIG. 4, the upper length of the gasket (440) is depicted as being longer than the lower length of the gasket (440), but it is not limited to this and can be modified according to the shape of the body part (430) and the leg part (432) of the rivet.

[0089] According to one embodiment, the distance between the point (431) where the body portion (430) and the leg portion (432) of the rivet are connected and the compression point (439) may correspond to the thickness of the case (420). Specifically, the distance between the point (431) where the body portion (430) and the leg portion (432) are connected and the compression point (439) may be less than or equal to the length obtained by adding the thickness of the gasket (440) to the thickness of the case (420). Since the gasket (440) is made of an elastic material, when the rivet is fitted into the electrolyte injection port, the gasket (440) is partially compressed and receives an elastic force attempting to restore it, as well as stress from the case (420), so that the rivet can be fixed so that it does not come out.

[0090] FIG. 5 is a plan view showing a cross-section of a secondary battery according to one embodiment of the present disclosure.

[0091] Referring to FIG. 5, a gasket (540) may be interposed between the case (520) and the rivet (530). The gasket (540) may be positioned between the rivet (530) and the case (520) to cover a part of the body portion (531) and the leg portion (532) of the rivet (530). A portion of the leg portion (532) not covered by the gasket (540) may include a step (534) protruding from the lower surface of the case (520). A compression point (539) may be formed at a location where the leg portion (532) of the rivet (530) contacts the inner surface of the electrolyte injection port. Specifically, the compression point (539) may be formed at the point where the outer surface of the gasket (540) surrounding the electrolyte injection port and the step (534) of the leg portion (532) meet.

[0092] According to one embodiment, the leg portion (532) of the rivet (530) may include a tapered outer surface (538). Specifically, the outer surface (538) of the step (534) protruding from the leg portion (532) may be tapered to facilitate the insertion of the rivet (530) into the electrolyte injection port.

[0093] The angle at which the outer surface (538) is tapered is not limited to 0 to 90 degrees. However, if the angle formed by the tapered outer surface (538) with the lower surface of the gasket (540) containing the compression point (539) is less than 20 degrees, the insertability of the rivet (530) may be reduced. If the angle formed by the tapered outer surface (538) with the lower surface of the gasket (540) containing the compression point (539) exceeds 80 degrees, the protruding step (534) may become excessively thin, and the compression point (539) may not be able to withstand force. Therefore, the angle at which the outer surface (538) is tapered is preferably between 20 and 80 degrees.

[0094] According to one embodiment, the outer surface (538) of the leg portion (532) may include a coating layer (537). The coating layer (537) may provide electrical insulation and prevent leakage of the electrolyte, inhibit corrosion that may occur when the rivet (530) is exposed to the electrolyte. Although FIG. 5 is illustrated as having the coating layer (537) placed only on a portion of the outer surface (538) of the leg portion (532), it is not limited thereto and may be placed on the entire surface of the leg portion (532). For example, the coating layer (537) may also be placed on the lower outer surface of the leg portion (532), the surface in contact with the step (534), or the gasket (540).

[0095] In one embodiment, the coating layer (537) may be made of a polymer coating comprising Teflon (PTFE, Polytetrafluoroethylene), polypropylene (PP, Polypropylene), polyethylene terephthalate (PET, Polyethylene terephthalate), polycarbonate (PC, Polycarbonate), or a combination thereof.

[0096] In one embodiment, the coating layer (537) may be made of a metal coating including nickel (Ni) plating or chrome (Cr) plating to minimize reaction with the electrolyte and protect the surface of the rivet (530).

[0097] In one embodiment, the coating layer (537) may be made of a ceramic coating comprising alumina (Al2O3), zirconia (ZrO2), paraylene, epoxy resin, or a combination thereof. The coating layer (537) is not limited to the materials listed above and may include various materials with excellent durability according to the choice of a person skilled in the art.

[0098] Other details regarding the configuration are as described above with reference to Fig. 4.

[0099] FIG. 6 is a perspective view showing a rivet according to one embodiment of the present disclosure.

[0100] Referring to FIG. 6, a rivet according to one embodiment may include a body portion (610) and a leg portion (620). The description of each component is the same as the description of the leg portion described above with reference to FIGS. 2 to 5.

[0101] According to one embodiment, the leg portion (620) of the rivet may include at least two legs (660). For example, as shown in FIG. 6, the leg portion (620) may include three legs (660). The legs (660) may be formed by splitting one end of the leg portion (620) connected to the body portion (610). Thus, the legs (660) may be spaced apart from each other at a specific distance. In one embodiment, the distance between the legs (660) may be 0.3 mm to 0.5 mm. The legs (660) may include a step (624). The step (624) may be located at one end opposite to the body portion (610).

[0102] FIG. 7 is a cross-sectional view of a secondary battery according to one embodiment of the present disclosure.

[0103] Referring to FIG. 7, a secondary battery (700) 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 cap plate (721), a current collector plate (712) connected to the electrode assembly (710), an electrode terminal (790) that penetrates one side of the case (720), a rivet (730), and a gasket (740).

[0104] The electrode assembly (710) is formed into a jelly roll state by sequentially winding the first electrode, the separator, and the second electrode. The first electrode and the second electrode each include a coated portion in which an active material is applied to both sides of a substrate formed from a thin metal plate, and an uncoated portion in which the substrate is exposed and the active material is not applied.

[0105] For example, the first electrode may be formed by coating an anode active material onto an aluminum (Al) substrate to form an anode, and the second electrode may be formed by coating a cathode active material onto a copper (Cu) substrate to form a cathode. The uncoated portion of the first electrode and the uncoated portion of the second electrode are respectively provided at both ends in the winding axis direction of the electrode assembly (710), but electrode terminals (790) and cases (720) having different polarities are provided together in the same direction. A cap plate (721) is located on the opposite side of the electrode terminal (790).

[0106] The case (720) is formed as a cylinder to house the electrode assembly (710), and the electrode terminal (790) and the cap plate (721) are respectively provided at both ends of the case (720) in the axial direction. The electrode terminal (790) is connected to the first electrode via the current collector plate (712) through a through-hole, and the case (720) is connected to the second electrode.

[0107] According to one embodiment, the case (720) includes a cap plate (721) that seals the opening of the case (720), and an electrolyte injection port may be formed in the approximately central part of the cap plate (721). The configuration of the rivet (730) and gasket (740) disposed through the electrolyte injection port formed in the cap plate (721) may be the same or similar to the configuration of the rivet and gasket described above with reference to FIGS. 1 to 6.

[0108] For example, the electrode terminal (790) may be installed in a through-structure on one side of the case (720). To this end, the electrode terminal (790) may have a rivet shape. The electrode terminal (790) is welded to the current collector plate (712) at one end and is positioned to penetrate the case (720), so that a part of the electrode terminal (790) is positioned on the outside of the case (720). The part of the electrode terminal (790) positioned on the outside of the case (720) may be formed to protrude above the surrounding outer surface of the case (720).

[0109] At this time, the current collector plate (712) is electrically and mechanically connected to the unoccupied portion of the first electrode through the electrode terminal (790). Specifically, the current collector plate (712) is electrically connected to the electrode terminal (790) in a structure that reduces resistance by contacting most of the unoccupied portion of the first electrode. Although not shown, an insulator is interposed between the electrode terminal (790) and the through hole to form a hermetic structure against the electrolyte, while being installed in a state of electrical insulation from the case (720).

[0110] Additionally, the case (720) has a fully open opening to allow the electrode assembly (710) to be inserted on the other side. A cap plate (721) can be attached to seal the opening after the electrode assembly (710) is inserted into the case (720).

[0111] In one embodiment, the case (720) and the cap plate (721) may be joined by welding. Specifically, the case (720) and the cap plate (721) may be welded using any one of ultrasonic welding, laser welding, resistance welding, TIG welding (Tungsten Inert Gas Welding), or a combination thereof. The welding method is not limited to the types of welding listed above, and various methods generally used for welding two materials may be used at the choice of a person skilled in the art.

[0112] Although not shown, a sealing tape may be attached to the outer surface of the jelly roll of the electrode assembly (710) so as to wrap it at least once. The electrode assembly (710) is inserted into the case (720) with the sealing tape attached, and the sealing tape may be positioned between the electrode assembly (710) and the case (720). Thus, the secondary battery assembled is prevented from moving up and down or forward and backward within the case (720), thereby preventing 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.

[0113] 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.

[0114] FIG. 8 is a flowchart illustrating an example of a method for manufacturing a secondary battery according to the present disclosure.

[0115] A method for manufacturing a secondary battery (800) according to one embodiment may be disclosed by sequentially stacking a first electrode, a separator, and a second electrode to produce an electrode assembly (S810).

[0116] Subsequently, an electrode assembly can be inserted into a case having an electrolyte injection port formed on one side (S820). The case includes a cap plate that seals the opening, and the electrolyte injection port may be formed in the cap plate. According to one embodiment, the shape of the case may be cylindrical, having a diameter of 40 mm to 50 mm.

[0117] After that, the electrolyte can be injected through the electrolyte injection port (S830).

[0118] Subsequently, the electrolyte injection port can be sealed by a rivet (S840). Here, the rivet may include a body portion that contacts the outer surface of the area where the electrolyte injection port is formed on the case, and a leg portion that contacts the inner surface of the area where the electrolyte injection port is formed on the case. Specifically, the rivet may include at least two leg portions. At least a portion of the leg portion of the rivet may include a step formed by bending outward. Additionally, the outer diameter of the leg portion may be larger than the inner diameter of the electrolyte injection port.

[0119] According to one embodiment, the leg portion of the rivet may include a tapered outer surface. Here, the outer surface of the leg portion may include a coating layer.

[0120] According to one embodiment, a groove with a shape corresponding to the body portion of a rivet may be formed around the electrolyte injection port in the case. Here, the depth of the groove may correspond to the thickness of the body portion of the rivet. The thickness of the body portion of the rivet may be 0.4 mm to 0.7 mm.

[0121] A method for manufacturing a secondary battery (800) according to one embodiment may further include the step of inserting a leg portion of a rivet into the interior of a case through an electrolyte injection port to form a compression point between the leg portion and the inner surface of the case. Here, the distance between the point where the body portion and the leg portion are connected and the compression point may correspond to the thickness of the case. According to one embodiment, a gasket may be interposed between the case and the rivet.

[0122] A method for manufacturing a secondary battery according to one embodiment may further include the step of sealing an opening of a case using a cap plate after the step of inserting an electrode assembly into a case.

[0123] Figure 9 is a drawing showing a method for manufacturing a secondary battery using blind rivets.

[0124] Referring to FIG. 9, after injecting electrolyte into the secondary battery (901) through the electrolyte injection port (910), the electrolyte injection port (910) can be sealed. When a blind rivet (930) is used to seal the electrolyte injection port (910), the cap plate of the secondary battery (901) may include an inwardly formed step for the process of inserting the blind rivet (930) and removing the core (920) for fixing it.

[0125] As a result, the interior (909) of the secondary battery (901) suffers a loss in capacity equal to the step formed inward. The present invention provides a rivet including a body portion and a leg portion, rather than a blind rivet (930), thereby eliminating the unnecessary process of removing the core (920) and reducing the step of the cap plate.

[0126] According to some embodiments of the present disclosure, by using a rivet having a structure effective for sealing an electrolyte injection port after injecting an electrolyte into a secondary battery, unnecessary processes in the process of sealing the electrolyte injection port can be eliminated, and the efficiency of the entire secondary battery manufacturing process can be increased.

[0127] According to some embodiments of the present disclosure, by simplifying the structure of a rivet that seals the electrolyte injection port of a secondary battery, the output efficiency per unit weight of the secondary battery can be increased without increasing the thickness of the case of the high-density secondary battery.

[0128] 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 in which a first electrode, a separator, and a second electrode are sequentially stacked; A case accommodating the above electrode assembly and having an electrolyte injection port formed on one side; and It includes a rivet that seals the above electrolyte injection port, A secondary battery comprising: a rivet comprising a body portion that contacts the outer surface of the region where the electrolyte injection port is formed on the case, and a leg portion that contacts the inner surface of the region where the electrolyte injection port is formed on the case.

2. In Paragraph 1, The above rivet is a secondary battery comprising at least two legs.

3. In Paragraph 2, A secondary battery in which a compression point is formed at a position where the leg portion of the above rivet contacts the inner surface of the above electrolyte injection port.

4. In Paragraph 3, A secondary battery comprising a step formed by bending at least a portion of the leg portion of the above rivet outward.

5. In Paragraph 3, A secondary battery, wherein the distance between the point where the body part and the leg part are connected and the compression point corresponds to the thickness of the case.

6. In Paragraph 1, A secondary battery comprising a tapered outer surface on the leg portion of the above rivet.

7. In Paragraph 1, A secondary battery in which the outer surface of the above-mentioned leg portion includes a coating layer.

8. In Paragraph 2, A secondary battery in which the outer diameter of the above-mentioned leg portion is larger than the inner diameter of the above-mentioned electrolyte injection port.

9. In Paragraph 1, A secondary battery having a body portion of the above rivet with a thickness of 0.4 mm to 0.7 mm.

10. In Paragraph 1, A secondary battery having a groove formed in the above case around the electrolyte injection port that corresponds to the body portion of the above rivet.

11. In Paragraph 10, A secondary battery in which the depth of the above groove corresponds to the thickness of the above body part of the above rivet.

12. In Paragraph 1, A secondary battery having a gasket interposed between the above case and the above rivet.

13. In Paragraph 1, The above case includes a cap plate that seals the opening of the above case, and The above electrolyte injection port is formed in the above cap plate, a secondary battery.

14. In Paragraph 1, The above case is a secondary battery having a cylindrical shape with a diameter of 40 mm to 50 mm.

15. A step of fabricating an electrode assembly by sequentially stacking a first electrode, a separator, and a second electrode; A step of inserting the electrode assembly into a case having an electrolyte injection port formed on one side; A step of injecting an electrolyte through the above electrolyte injection port; and A step of sealing the electrolyte injection port by means of a rivet; Includes, A method for manufacturing a secondary battery, wherein the rivet comprises a body portion that contacts the outer surface of the region where the electrolyte injection port is formed on the case, and a leg portion that contacts the inner surface of the region where the electrolyte injection port is formed on the case.

16. In Paragraph 15, A method for manufacturing a secondary battery, wherein the above-mentioned rivet comprises at least two legs.

17. In Paragraph 15, A method for manufacturing a secondary battery, further comprising the step of inserting the leg portion of the rivet into the interior of the case through the electrolyte injection port to form a compression point between the leg portion and the inner surface of the case.

18. In Paragraph 15, A method for manufacturing a secondary battery, wherein a gasket is interposed between the above case and the above rivet.

19. In Paragraph 15, A method for manufacturing a secondary battery, wherein the above case includes a cap plate, and the electrolyte injection port is formed in the cap plate.

20. In Paragraph 19, A method for manufacturing a secondary battery, comprising the step of inserting the electrode assembly into the case, and further including the step of sealing the opening of the case using the cap plate.

Images