Secondary battery and secondary battery manufacturing method

Abstract

The present disclosure provides a secondary battery and a secondary battery manufacturing method. The secondary battery according to the disclosure comprises: an electrode assembly formed by winding a first electrode, a separator and a second electrode; and a case for accommodating the electrode assembly, wherein: an uncoated portion of the first electrode includes a first core-side cutting section, a first core-side bending section, a first outer-side bending section, and a first outer-side cutting section; and an uncoated portion of the first core-side bending section can be bent in the centrifugal direction of the electrode assembly.

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]

[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 an embodiment of the present invention for solving the above technical problem comprises an electrode assembly formed by winding a first electrode, a separator, and a second electrode, and a case for housing the electrode assembly, wherein the unwound portion of the first electrode includes a first core-side cutting section, a first core-side bending section, a first outer-side bending section, and a first outer-side cutting section, and the unwound portion of the first core-side bending section may be bent in the centrifugal direction of the electrode assembly.

[0011] According to one embodiment of the present disclosure, the unworn portion of the first outer bending section may be bent in the centroidal direction of the electrode assembly.

[0012] A secondary battery according to one embodiment of the present disclosure further includes a first current collector plate electrically connected to a first electrode, and one end of the unoccupied portion of the first winding core side cutting section may be cut so as to be spaced apart from the first current collector plate.

[0013] According to one embodiment of the present disclosure, the length of the first core-side cutting section may correspond to a length of one to three turns from the inner diameter of the electrode assembly.

[0014] According to one embodiment of the present disclosure, one end of the unworn portion of the first outer cutting section may be cut so that the unworn portion is spaced apart from the case.

[0015] According to one embodiment of the present disclosure, the length of the first outer cutting section may correspond to a length wound 1 to 3 times from the outer diameter of the electrode assembly.

[0016] According to one embodiment of the present disclosure, the length of the unwound portion of the first core-side bending section may become shorter as it approaches the core-side of the electrode assembly.

[0017] According to one embodiment of the present disclosure, the length of the unworn portion of the first outer bending section may become shorter as it extends toward the outer side of the electrode assembly.

[0018] According to one embodiment of the present disclosure, the diameter of the case may be 40 mm to 50 mm.

[0019] According to one embodiment of the present disclosure, the unincorporated portion of the second electrode may be positioned in a direction opposite to that of the unincorporated portion of the first electrode.

[0020] According to one embodiment of the present disclosure, the unwound portion of the second electrode includes a second core-side cutting section, a second core-side bending section, a second outer-side bending section, and a second outer-side cutting section, and the unwound portion of the second core-side bending section may be bent in the centrifugal direction of the electrode assembly.

[0021] According to one embodiment of the present disclosure, the unworn portion of the second outer bending section may be bent in the centripetal direction of the electrode assembly.

[0022] A secondary battery according to one embodiment of the present disclosure further includes a second current collector plate electrically connected to a second electrode, and one end of the unoccupied portion of the second winding core side cutting section may be cut so as to be spaced apart from the second current collector plate.

[0023] According to one embodiment of the present disclosure, the length of the second core-side cutting section may correspond to a length of one to three turns from the inner diameter of the electrode assembly.

[0024] According to one embodiment of the present disclosure, one end of the unworn portion of the second outer cutting section may be cut so that the unworn portion is spaced apart from the case.

[0025] According to one embodiment of the present disclosure, the length of the second outer side cutting section may correspond to a length wound 1 to 3 times from the outer diameter of the electrode assembly.

[0026] According to one embodiment of the present disclosure, the length of the unwound portion of the second core-side bending section may become shorter as it approaches the core-side of the electrode assembly.

[0027] According to one embodiment of the present disclosure, the length of the unworn portion of the second outer bending section may become shorter as it extends toward the outer side of the electrode assembly.

[0028] According to one embodiment of the present disclosure, the length of the first outer cutting section and the length of the second outer cutting section may be different.

[0029] A method for manufacturing a secondary battery according to an embodiment of the present invention for solving a technical problem comprises the steps of winding a first electrode, a separator, and a second electrode to form an electrode assembly and inserting the electrode assembly into a case, wherein the unwound portion of the first electrode includes a first core-side cutting section, a first core-side bending section, a first outer-side bending section, and a first outer-side cutting section, and the unwound portion of the first core-side bending section may be bent in the centrifugal direction of the electrode assembly.

[0030]

[0031] By using a novel method of bending the non-removable portion of a secondary battery according to some embodiments of the present disclosure, the portion of the non-removable portion that is removed to improve processability, such as preventing short circuits and securing welding space, is minimized, thereby suppressing problems of reduced output / lifespan of the secondary battery and deformation of the electrode assembly caused by the removal of the non-removable portion.

[0032] According to some embodiments of the present disclosure, the amount of unused portion removed from the core-side cutting section and the outer-side cutting section of a secondary battery is minimized, thereby improving the current path.

[0033] 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.

[0034]

[0035] 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.

[0036] FIG. 1 is a schematic diagram illustrating a secondary battery according to one embodiment of the present disclosure.

[0037] FIG. 2 is a plan view showing a pre-winding electrode assembly according to one embodiment of the present disclosure.

[0038] FIG. 3 is a plan view showing a pre-winding electrode assembly according to one embodiment of the present disclosure.

[0039] FIG. 4 is a drawing showing an electrode assembly according to one embodiment of the present disclosure as seen from the direction of the first electrode.

[0040] FIG. 5 is a cross-sectional view showing the area around the first core-side cutting section according to one embodiment of the present disclosure.

[0041] FIG. 6 is a cross-sectional view showing the area around the second core-side cutting section according to one embodiment of the present disclosure.

[0042] FIG. 7 is a cross-sectional view showing the area around the first outer cutting section according to one embodiment of the present disclosure.

[0043] FIG. 8 is a cross-sectional view showing the area around the second outer cutting section according to one embodiment of the present disclosure.

[0044] FIG. 9 is a cross-sectional view of a secondary battery according to one embodiment of the present disclosure.

[0045] FIG. 10 is a flowchart illustrating an example of a method for manufacturing a secondary battery according to the present disclosure.

[0046]

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] The terms used in this specification are intended to describe embodiments of the present disclosure and are not intended to limit the present disclosure.

[0060] FIG. 1 is a schematic diagram illustrating a secondary battery according to one embodiment of the present disclosure.

[0061] Referring to FIG. 1, a secondary battery (100) according to one embodiment of the present invention may include an electrode assembly (102) formed by winding a first electrode (110), a separator (130), and a second electrode (120), and a case (104) that accommodates the electrode assembly (102). The first electrode (110), the second electrode (120), and the separator (130) may be impregnated with an electrolyte (not shown).

[0062] 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).

[0063] The first electrode (110) includes a region on both sides of a first substrate (114), each formed of a thin metal plate, where a first active material (112) is applied, and a non-exposed region (190), where the first active material (112) is not applied and the first substrate (114) is exposed. Likewise, the second electrode (120) also includes a region on both sides of a second substrate (124), each formed of a thin metal plate, where a second active material (122) is applied, and a non-exposed region (not shown), where the second active material (122) is not applied and the second substrate (124) is exposed.

[0064] The first electrode (110) may be an electrode corresponding to the positive or negative electrode in the secondary battery (100). The second electrode (120) may be an electrode corresponding to the opposite electrode 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.

[0065] For example, the first electrode (110) can be formed by coating a positive active material on an aluminum (Al) substrate to form a positive electrode, and the second electrode (120) can be formed by coating a negative active material on a copper (Cu) substrate to form a negative electrode.

[0066] In a secondary battery (100) according to one embodiment of the present invention, the first electrode (110) may include a plurality of unoccupied portions (190). The plurality of unoccupied portions (190) of the first electrode (110) may all be arranged on one side of the electrode assembly (102) in the same direction. In contrast, the unoccupied portion (not shown) of the second electrode (120) according to one embodiment of the present disclosure may be arranged in a direction opposite to that of the unoccupied portion (190) of the first electrode (110).

[0067] The unwound portion (190) of the first electrode (110) arranged in the same direction may include a first core-side cutting section (192), a first core-side bending section (194), a first outer-side bending section (196), and a first outer-side cutting section (198). Specifically, the unwound portion (190) of the first electrode (110) may include a first core-side cutting section (192), a first core-side bending section (194), a first outer-side bending section (196), and a first outer-side cutting section (198) in a concentric shape formed sequentially from the core side to the centrifugal side of the electrode assembly (102). This will be described later in FIG. 4.

[0068] According to one embodiment of the present disclosure, the unwound portion (190) of the first core-side bending section (194) may be bent in the centrifugal direction (B) of the electrode assembly (102). In contrast, according to one embodiment, the unwound portion (190) of the first outer-side bending section (196) may be bent in the centripetal direction (A) of the electrode assembly (102). Here, by bending the unwound portion (190) of the first core-side bending section (194) in the centrifugal direction (B) of the electrode assembly (102), the portion of the unwound portion (190) that is removed to secure the core cavity of the electrode assembly (102) can be minimized. Additionally, the area of ​​the first core-side cutting section (192) located around the cavity can be minimized.

[0069] By folding the bare portion (190) of a secondary battery (100) in a new manner according to some embodiments of the present disclosure, the portion of the bare portion (190) that is removed to improve processability, such as preventing short circuits and securing welding space, is minimized, thereby suppressing the problem of reduced output / lifespan of the secondary battery (100) and deformation of the electrode assembly (102) caused by the removal of the bare portion (190).

[0070] The case (104) forms the overall exterior of the secondary battery (100) 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 (104) may provide a space for accommodating the electrode assembly (102). For example, if the secondary battery (100) is a cylindrical secondary battery, the case (104) may have the shape of a cylinder.

[0071] The case (104) may have a fully open opening to allow the electrode assembly (102) to be inserted on the other side. A vent plate (106) may be attached to seal the opening of the case (104) after the electrode assembly (102) is inserted into the case (104).

[0072] Specifically, the vent plate (106) is configured to cover the opening of the case (104) and seals the interior of the secondary battery (100) from the external environment to prevent leakage of electrolyte, etc., protects the internal components of the secondary battery (100) from external moisture or dust, and provides a welded or contact area to an external component (e.g., an external terminal) to electrically connect the secondary battery cell.

[0073] A secondary battery (100) according to one embodiment of the present disclosure may further include a first current collector plate (140) electrically connected to a first electrode (110). Specifically, the electrode assembly (102) may be electrically connected to the first current collector plate (140) located at the bottom of the vent plate (106) through the non-removable portion (190) of the first electrode (110).

[0074] For example, the unbonded portion (190) of the first electrode (110) can be welded and joined to the first current collector plate (140). A portion of the first current collector plate (140) can protrude toward the electrode assembly (102) so as to be welded to the unbonded portion (190) of the first electrode (110).

[0075] Specifically, the unwelded portion (190) of the first electrode (110) may be welded to the first collector plate (140) 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.

[0076] Additionally, in one embodiment, the secondary battery (100) may further include a gasket (150) interposed between the vent plate (106) and the first current collector plate (140). Here, the gasket may perform an insulating function by being composed of a material that creates a gap between the vent plate (106) and the first current collector plate (140) while simultaneously sealing the secondary battery (100) and severing the electrical connection. As a result, the vent plate (106) can be electrically insulated from the electrode assembly (102).

[0077] The unwound portion (190) of the first core-side cutting section (192) may have one end of the unwound portion (190) cut so as to be spaced apart from the first collector plate (140). According to one embodiment, the length of the first core-side cutting section (192) may correspond to a length that is wound 1 to 3 times from the inner diameter of the electrode assembly (102).

[0078] Additionally, one end of the bare portion (190) of the first outer side cutting section (198) may be cut so as to be spaced apart from the case (104). According to one embodiment, the length of the first outer side cutting section (198) may correspond to a length that is wound 1 to 3 times from the outer diameter of the electrode assembly (102). This will be described later in FIGS. 2 to 8.

[0079] For the purpose of explaining the invention, the secondary battery (100) in FIGS. 1 to 8 below is shown in the form of a cylindrical battery, but the scope of the present disclosure is not limited thereto. The secondary battery (100) of the present invention is not limited to a cylindrical secondary battery and includes secondary batteries of any shape, such as a prismatic secondary battery, a pouch secondary battery, or a coin secondary battery.

[0080] FIG. 2 is a plan view showing a pre-winding electrode assembly (200) according to one embodiment of the present disclosure.

[0081] Referring to FIG. 2, an electrode assembly (200) according to one embodiment of the present disclosure may include a first electrode (210) and a second electrode (230). The first electrode (210) may include a non-existent portion (212) of the first electrode, which is an area where the first active material (214) is not applied, and the second electrode (230) may include a non-existent portion (232) of the second electrode, which is an area where the second active material (234) is not applied. The non-existent portion (212) of the first electrode and the non-existent portion (232) of the second electrode may include a plurality of metal segments formed by notching.

[0082] According to one embodiment of the present disclosure, the unoccupied portion (232) of the second electrode may be positioned in a direction opposite to that of the unoccupied portion (212) of the first electrode. In FIG. 2, the unoccupied portion (232) of the second electrode is shown positioned at the bottom of the electrode assembly (200) and the unoccupied portion (212) of the first electrode is shown positioned at the bottom of the electrode assembly (200), but is not limited thereto.

[0083] The unwound portion (212) of the first electrode (210) arranged in the same direction may include a first core-side cutting section (222), a first core-side bending section (224), a first outer-side bending section (226), and a first outer-side cutting section (228) arranged sequentially from the core-side (C) to the outer-side (D).

[0084] According to one embodiment, one end of the unwound portion (212) of the first core-side cutting section (222) may be cut. Here, the length of the first core-side cutting section (222) may correspond to a length that is wound 1 to 3 times from the inner diameter of the electrode assembly. The height of the unwound portion (212) of the cut first core-side cutting section (222) is not limited and may include various lengths depending on the selection within a range that does not touch the first current collector plate of the secondary battery.

[0085] According to one embodiment, one end of the unwound portion (212) of the first outer-side cutting section (228) may be cut so that the unwound portion (212) is spaced apart from the case. Here, the length of the first outer-side cutting section (228) may correspond to a length that is wound 1 to 3 times from the outer diameter of the electrode assembly. The height of the unwound portion (212) of the cut first outer-side cutting section (228) is not limited and may include various lengths depending on the selection within a range that does not touch the first current collector plate of the secondary battery. In addition, the length of the first winding-side cutting section (222) and the length of the first outer-side cutting section (228) may be different from each other.

[0086] The non-removable portion (232) of the second electrode (230) arranged in the same direction may include a second core-side cutting section (242), a second core-side bending section (244), a second outer-side bending section (246), and a second outer-side cutting section (248) arranged sequentially from the core-side (C) to the outer-side (D).

[0087] Here, the unwound portion (232) of the second core-side bending section (244) may be bent in a centrifugal direction after winding the electrode assembly (200). Additionally, the unwound portion (232) of the second outer-side bending section (246) may be bent in a centripetal direction after winding the electrode assembly (200).

[0088] The length of the first outer side cutting section (228) and the length of the second outer side cutting section (248) are not limited and may differ from each other. Likewise, the length of the first core side cutting section (222) and the length of the second core side cutting section (248) are not limited and may differ from each other.

[0089] FIG. 3 is a plan view showing a pre-winding electrode assembly (300) according to one embodiment of the present disclosure.

[0090] Referring to FIG. 3, an electrode assembly (300) according to one embodiment of the present disclosure may include a first electrode (310) and a second electrode (330). The first electrode (310) may include a non-existent portion (312) of the first electrode, which is an area where the first active material (314) is not applied, and the second electrode (330) may include a non-existent portion (332) of the second electrode, which is an area where the second active material (334) is not applied. The non-existent portion (312) of the first electrode and the non-existent portion (332) of the second electrode may include a plurality of metal segments formed by notching.

[0091] According to one embodiment of the present disclosure, the unoccupied portion (332) of the second electrode may be positioned in a direction opposite to that of the unoccupied portion (312) of the first electrode. In FIG. 3, the unoccupied portion (332) of the second electrode is shown positioned at the bottom of the electrode assembly (300) and the unoccupied portion (312) of the first electrode is shown positioned at the bottom of the electrode assembly (300), but is not limited thereto.

[0092] The unwound portion (312) of the first electrode (310) arranged in the same direction may include a first core-side cutting section (322), a first core-side bending section (324), a first outer-side bending section (326), and a first outer-side cutting section (328) arranged sequentially from the core-side (C) to the outer-side (D).

[0093] Additionally, the non-removable portion (332) of the second electrode (330) arranged in the same direction may include a second core-side cutting section (342), a second core-side bending section (344), a second outer-side bending section (346), and a second outer-side cutting section (348) arranged sequentially from the core-side (C) to the outer-side (D).

[0094] According to one embodiment of the present disclosure, the length of the unwound portion (312) of the first core-side bending section (324) may become shorter as it approaches the core side (C) of the electrode assembly (300). Additionally, according to one embodiment, the length of the unwound portion of the first outer-side bending section (326) may become shorter as it approaches the outer side (D) of the electrode assembly.

[0095] Similar to the first electrode, the length of the unwound portion (332) of the second core-side bending section (344) may become shorter as it approaches the core side (C) of the electrode assembly (300). Additionally, according to one embodiment, the length of the unwound portion (332) of the second outer-side bending section (346) may become shorter as it approaches the outer side (D) of the electrode assembly (300).

[0096] Through this, the unused portions (312, 332) removed to secure the core cavity in the first core-side cutting section (322) and the second core-side cutting section (342) of the electrode assembly (300) can be minimized. Additionally, the unused portions (312, 332) removed to secure a safe separation distance from the case in the first outer-side cutting section (328) and the second outer-side cutting section (348) can be minimized.

[0097] Other details regarding the configuration are as described above with reference to Fig. 2.

[0098] FIG. 4 is a drawing showing an electrode assembly (400) according to one embodiment of the present disclosure as seen from the direction of the first electrode.

[0099] Referring to FIG. 4, the unwound portion of the first electrode, which is arranged in the same direction with respect to the electrode assembly (400), may include a first core-side cutting section (402), a first core-side bending section (404), a first outer-side bending section (406), and a first outer-side cutting section (408). The arrows shown in FIG. 4 indicate the direction in which the unwound portion of the first electrode is bent. That is, in the first core-side bending section (404), the unwound portion of the first electrode may be bent in the centrifugal direction, and in the first outer-side bending section (406), the unwound portion of the first electrode may be bent in the centripetal direction.

[0100] Specifically, the unwound portion (190) of the first electrode (110) may include a first core-side cutting section (402), a first core-side bending section (404), a first outer-side bending section (406), and a first outer-side cutting section (408) in the shape of concentric circles formed sequentially from the core (410) side of the electrode assembly (102) to the centrifugal (420) side. Although not shown in FIG. 4, a second electrode positioned in the opposite direction to the first electrode is also identical to the description of the first electrode described above.

[0101] FIG. 5 is a cross-sectional view showing the area around the first core-side cutting section according to one embodiment of the present disclosure.

[0102] Referring to FIG. 5, one end of the unwound portion (590) of the first electrode (510) can be cut so that the unwound portion (590) of the first core-side cutting section (592) is spaced apart from the first current collector plate (540) which is electrically insulated from the vent plate (506). According to one embodiment, the length of the first core-side cutting section (592) may correspond to a length that is wound 1 to 3 times from the inner diameter of the electrode assembly (502).

[0103] A separator (530) is interposed between the first electrode (510) and the second electrode (520), and in order to insulate the first electrode (510) and the second electrode (520), the height of the separator (530) may be greater than the height of the first electrode (510) or the height of the second electrode (520).

[0104] According to one embodiment of the present disclosure, the unwound portion (514) of the first core-side bending section (594) may be bent in the centrifugal direction of the electrode assembly (502). In contrast, according to one embodiment, the unwound portion (516) of the first outer-side bending section (596) may be bent in the centripetal direction of the electrode assembly (502). Here, by bending the unwound portion (514) of the first core-side bending section (594) in the centrifugal direction of the electrode assembly (502), the portion of the unwound portion (590) that is removed to secure the core cavity (591) of the electrode assembly (502) may be minimized.

[0105] Other details regarding the configuration are as described above with reference to Fig. 1.

[0106] FIG. 6 is a cross-sectional view showing the area around the second core-side cutting section according to one embodiment of the present disclosure.

[0107] Referring to FIG. 6, a secondary battery according to one embodiment of the present disclosure further includes a second current collector plate (640) electrically connected to a second electrode (620), and one end of the unoccupied portion (690) of the second winding core side cutting section (692) may be cut so that the unoccupied portion (690) is spaced apart from the second current collector plate (640).

[0108] According to one embodiment, the length of the second core-side cutting section (692) may correspond to a length that is wound 1 to 3 times from the inner diameter of the electrode assembly (602).

[0109] Here, the second current collector plate (640) can be electrically connected to a rivet (606). The second current collector plate (640) can be electrically insulated by a case (604) and a gasket (650). Additionally, a separator (630) is interposed between the first electrode (610) and the second electrode (620), and in order to insulate the first electrode (610) and the second electrode (620), the height of the separator (630) may be greater than or equal to the height of the first electrode (610) or the second electrode (620).

[0110] According to one embodiment of the present disclosure, the unwound portion (624) of the second core-side bending section (694) may be bent in the centrifugal direction of the electrode assembly (602). In contrast, according to one embodiment, the unwound portion (626) of the second outer-side bending section (696) may be bent in the centripetal direction of the electrode assembly (602). Here, by bending the unwound portion (624) of the second core-side bending section (694) in the centrifugal direction of the electrode assembly (602), the portion of the unwound portion (690) that is removed to secure the core cavity (691) of the electrode assembly (602) may be minimized.

[0111] Other details regarding the configuration are as described above with reference to Fig. 5.

[0112] FIG. 7 is a cross-sectional view showing the area around the first outer cutting section according to one embodiment of the present disclosure.

[0113] Referring to FIG. 7, the unworn portion (718) of the first outer-side cutting section (798) may have one end of the unworn portion (718) cut so as to be spaced apart from the case (704). According to one embodiment, the length of the first outer-side cutting section (798) may correspond to a length that is wound 1 to 3 times from the outer diameter of the electrode assembly (702).

[0114] The unworn portion (716) of the first outer bending section (796) can be bent in the centripetal direction of the electrode assembly (702). The unworn portion surface (790) created by connecting a plurality of unworn portions (716) of the first outer bending section (796) can be electrically connected to the first current collector plate (740).

[0115] At the outermost part of the first outer edge cutting section (798), a separator (730) or an insulator extending from the separator (730) may be disposed to insulate the first electrode (710) or the second electrode (720) from the case (704).

[0116] Other details regarding the configuration are as described above with reference to Fig. 1.

[0117] FIG. 8 is a cross-sectional view showing the area around the second outer cutting section according to one embodiment of the present disclosure.

[0118] Referring to FIG. 8, the bare portion (828) of the second outer-side cutting section (898) may have one end of the bare portion (828) cut so as to be spaced apart from the case (804). According to one embodiment, the length of the second outer-side cutting section (898) may correspond to a length that is wound 1 to 3 times from the outer diameter of the electrode assembly (802).

[0119] The unoccupied portion (826) of the second outer bending section (896) can be bent in the centripetal direction of the electrode assembly (802). The unoccupied portion surface (890) formed by connecting a plurality of unoccupied portions (826) of the second outer bending section (896) can be electrically connected to the second current collector plate (840). Here, the second current collector plate (840) can be electrically insulated from the gasket (850) by the case (804).

[0120] At the outermost part of the second outer edge cutting section (898), a separator (830) or an insulator extending from the separator (830) may be disposed to insulate the first electrode (810) or the second electrode (820) from the case (804).

[0121] Other details regarding the configuration are as described above with reference to Fig. 1.

[0122] FIG. 9 is a cross-sectional view of a secondary battery according to one embodiment of the present disclosure.

[0123] Referring to FIG. 9, a secondary battery according to one embodiment of the present disclosure includes an electrode assembly (910) that performs charging and discharging, a case (920) that houses the electrode assembly (910), a first current collector plate (930) and a second current collector plate (950) connected to the electrode assembly (910), an electrode terminal (941), a vent cap plate (942), and a gasket (960). In FIG. 9, the vent cap plate (942) is shown positioned on the upper part of the secondary battery and the electrode terminal (941) is shown positioned on the lower part of the secondary battery, but is not limited thereto. Depending on the usage environment or requirements of the secondary battery, the vent cap plate (942) and the electrode terminal (941) may be changed to be positioned on the lower part and the upper part of the secondary battery, respectively.

[0124] The electrode assembly (910) is formed into a cylindrical jelly roll state with an empty core by winding the first electrode (911a, 911b), separator (913), and second electrode (912a, 912b). The first electrode (911a, 911b) and the second electrode (912a, 912b) each include a coated portion (911a, 912a) in which an active material is applied to both sides of a substrate formed by a thin metal plate, and an uncoated portion (911b, 912b) in which the substrate is exposed and the active material is not applied.

[0125] The first electrode (911a, 911b) may be an electrode corresponding to a positive or negative electrode in a secondary battery. The second electrode (912a, 912b) may be an electrode corresponding to a pole opposite to the first electrode (911a, 911b). For example, if the first electrode (911a, 911b) is a positive electrode, the second electrode (912a, 912b) may be a negative electrode. Conversely, if the first electrode (911a, 911b) is a negative electrode, the second electrode (912a, 912b) may be a positive electrode.

[0126] For example, the first electrode (911a, 911b) can be formed as a positive electrode by coating a positive active material on an aluminum (Al) substrate, and the second electrode (912a, 912b) can be formed as a negative electrode by coating a negative active material on a copper (Cu) substrate. The uncoated portion (911b) of the first electrode and the uncoated portion (912b) of the second electrode are respectively provided at both ends in the winding axis direction of the electrode assembly (910), but electrode terminals (941) and cases (920) having different polarities are provided together in the same direction. A vent cap plate (942) is located on the opposite side of the electrode terminal (941).

[0127] The electrode assembly (910) including the first electrode (911a, 911b) and the second electrode (912a, 912b) may have the same or similar configuration as the electrode assembly (102, 200, 300, 400, 502, 602, 702, 802) described with reference to FIGS. 1 to 8.

[0128] The case (920) is formed as a cylinder to house the electrode assembly (910), and the electrode terminal (941) and the vent cap plate (942) are respectively provided at both ends of the case (920) in the axial direction so as to face each other.

[0129] According to one embodiment of the present disclosure, the diameter of the case (920) may be 40 mm to 50 mm.

[0130] The electrode terminal (941) is connected to the first electrode (911a, 911b) via the first current collector plate (930) through a rivet (943), and the case (920) is connected to the second electrode (912a, 912b) via the second current collector plate (950). At this time, the vent cap plate (942) is electrically separated from the second current collector plate (950) and the case (920) and does not have polarity.

[0131] An electrode terminal (941) connected to the first electrode (911a, 911b) of the electrode assembly (910) inserted into the case (920) from the outside is installed on one side of the case. The case (920) has a through hole (921) that is partially open on one side.

[0132] For example, the electrode terminal (941) may be installed in a through hole (921) of the case (920) in a riveted structure. To this end, the electrode terminal (941) may be connected to a rivet (943). One end of the rivet (943) is welded to the first current collector plate (930) and positioned to pass through the through hole (921). The electrode terminal (941) is connected to the rivet (943) and positioned on the outside of the case (920). The electrode terminal (941) may be formed to protrude above the outer surface of the case (920) around the through hole (921) and used as an anode terminal. At this time, the first current collector plate (930) becomes an anode current collector plate.

[0133] At this time, the first current collector plate (930) is electrically connected to the unoccupied portion (911b) of the first electrode through a rivet (943) and is electrically and mechanically connected to the electrode terminal (941). The first current collector plate (930) is electrically connected to the electrode terminal (941) in a structure that reduces resistance by contacting most of the unoccupied portion (911b) of the first electrode. The rivet (943) included in the electrode terminal (941) is installed in a state of electrical insulation from the case (920) while forming a hermetic structure against the electrolyte by interposing an insulator (923) in the through hole (921).

[0134] Here, the insulator (923) may be made of a polymer comprising ethylene propylene rubber (EPDM), polypropylene (PP), polyimide (PI), polyethylene terephthalate (PET), polycarbonate (PC), or a combination thereof.

[0135] As another example, the insulator (923) 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 (923) is not limited to the materials listed above and may include various materials with excellent plasticity and insulation properties depending on the choice.

[0136] In one embodiment, the first current collector plate (930) may include a metal plate (931) comprising at least one bridge (932). For example, the first current collector plate (930) 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 (931) and the bridge (932) constituting the first current collector plate (930) may all be made of the same material to form a single unit.

[0137] Here, the bridge (932) of the first collector plate (930) can be configured to break if a current exceeding a set value flows. For example, the bridge (932) normally operates as part of a circuit through which current flows, but if a current exceeding what is needed flows, it can act as a fuse that melts due to the heat generated to cut off the circuit.

[0138] An insulating tape (945) may be attached to one side of the first current collector plate (930). The insulating tape (945) may be interposed between the first current collector plate (930) and the case (920) or between the uninsulated portion (911b) of the first electrode and the case (920) to electrically insulate each component. In one embodiment, the central portion of the insulating tape (945) may include a perforation (946) corresponding to the shape of a rivet (943) so that the rivet (943) can come into contact with the first current collector plate (930). Additionally, the insulating tape (945) may include a side wall (947) to wrap around a part of the electrode assembly (910).

[0139] Additionally, the case (920) is provided with a fully open opening (922) to allow the electrode assembly (910) to be inserted on the other side. The vent cap plate (942) seals the opening (922) after the electrode assembly (910) is inserted into the case (920) and is electrically separated from the case (920).

[0140] At this time, the second current collector plate (950) is electrically connected to the non-electrical portion (912b) of the second electrode and is electrically connected to the case (920). The second current collector plate (950) is connected to the case (920) in a structure that reduces resistance by contacting most of the non-electrical portion (912b) of the second electrode.

[0141] The second current collector plate (950) includes a bottom portion (951) welded to the non-bonded portion (912b) of the second electrode and a wing portion (952) formed adjacent to the bottom portion (951) and welded to the beading portion (929). The second current collector plate (950) is formed by cutting and bending a circular plate, and is provided with a plurality of bottom portions (951) and wing portions (952), respectively, and is arranged alternately with one another along the circumferential direction. In one embodiment, the wing portion (952) can repeatedly form an axial (upward) bend and a radial (outer) bend of the electrode assembly (910).

[0142] In one embodiment, when the uncoated portion (912b) of the second electrode and the bottom portion (951) of the second current collector plate (950) are welded, the bottom portion (951) can form a weld line in the diameter direction of the second current collector plate (950). Thus, the bottom portion (951) can be evenly connected along the circumferential direction in the area of ​​the uncoated portion (912b) of the second electrode, and the wing portion (952) can be evenly connected along the circumferential direction in the area of ​​the beading portion (929). This enables a uniform current flow along the circumferential direction from the uncoated portion (912b) of the second electrode to the entire area of ​​the beading portion (929) of the case (920).

[0143] Additionally, the second collector plate (950) is provided with a hole (953) in the center, so it can absorb and mitigate deformation caused by welding between the bottom part (951) and the non-welded part (912b) of the second electrode, as well as vibrations and shocks that may be transmitted between the wing part (952) and the bottom part (951). The hole (953) may have a size within a range that can absorb vibrations and shocks without increasing current resistance between the wing part (952) and the bottom part (951).

[0144] The vent cap plate (942) is electrically separated from the second current collector plate (950) and installed in the opening (922) of the case (920) by a clamping process. Alternatively, the vent cap plate (942) is installed in the opening (922) of the case (920) through a welding process. Due to the connection of the second current collector plate (950), the case (920) can be used as a negative terminal. At this time, the second current collector plate (950) becomes a negative current collector plate.

[0145] The vent cap plate (942) may have a notch (944) formed on its inner surface. The notch (944) 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 (944) is designed to be easily cut open by receiving concentrated internal pressure during an abnormal event. The notch (944) may be formed over the entire area along the circumferential direction of the vent plate (942), or it may be formed in multiple locations spaced apart at set intervals.

[0146] The gasket (960) is interposed between the second current collector plate (950) and the vent cap plate (942) and between the second current collector plate (930) and the case (920), and acts as a seal through the beading portion (929) or clamping process. Additionally, the gasket (960) can form an airtight structure against the electrolyte between the second current collector plate (930) and the opening (922) of the case (920).

[0147] For example, the gasket (960) 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.

[0148] The sealing tape (990) can be attached to wrap the outer surface of the jelly roll of the electrode assembly (910) at least once. Additionally, the electrode assembly (910) is inserted into the case (920) with the sealing tape (990) attached, and the sealing tape (990) can be positioned between the electrode assembly (910) and the case (920). Thus, the secondary battery assembled is prevented from moving the electrode assembly (910) up and down or forward and backward within the case (920), thereby preventing the separation of terminals or damage to the components, and even when the electrode assembly (910) expands due to charging and discharging, cracks in the case (920) or the electrode assembly (910) caused by excessive expansion of the electrode assembly (910) can be suppressed.

[0149] 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.

[0150] FIG. 10 is a flowchart illustrating an example of a method for manufacturing a secondary battery according to the present disclosure.

[0151] A method for manufacturing a secondary battery (1000) according to one embodiment of the present invention may be disclosed by winding a first electrode, a separator, and a second electrode to form an electrode assembly (S1010).

[0152] Subsequently, the electrode assembly can be inserted into the case (S1020). Here, the unwound portion of the first electrode includes a first core-side cutting section, a first core-side bending section, a first outer-side bending section, and a first outer-side cutting section, and the unwound portion of the first core-side bending section can be bent in the centrifugal direction of the electrode assembly.

[0153] According to some embodiments of the present disclosure, the amount of unused portion removed from the core-side cutting section and the outer-side cutting section of a secondary battery is minimized, thereby improving the current path.

[0154] 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 winding a first electrode, a separator, and a second electrode; and It includes a case that accommodates the above electrode assembly, and The unwound portion of the first electrode includes a first core-side cutting section, a first core-side bending section, a first outer-side bending section, and a first outer-side cutting section. The unworn portion of the first core-side bending section is bent in the centrifugal direction of the electrode assembly, a secondary battery.

2. In Paragraph 1, A secondary battery in which the unoccupied portion of the first outer bending section is bent in the centripetal direction of the electrode assembly.

3. In Paragraph 1, It further includes a first current collector plate electrically connected to the first electrode, and A secondary battery in which one end of the unoccupied portion of the first core-side cutting section is cut so as to be spaced apart from the first current collector plate.

4. In Paragraph 3, A secondary battery, wherein the length of the first core-side cutting section corresponds to a length wound 1 to 3 times from the inner diameter of the electrode assembly.

5. In Paragraph 1, A secondary battery in which one end of the blank portion is cut so that the blank portion of the first outer side cutting section is spaced apart from the case.

6. In Paragraph 5, A secondary battery, wherein the length of the first outer side cutting section corresponds to a length wound 1 to 3 times from the outer diameter of the electrode assembly.

7. In Paragraph 1, A secondary battery in which the length of the unwound portion of the first core-side bending section becomes shorter as it approaches the core-side of the electrode assembly.

8. In Paragraph 1, A secondary battery in which the length of the unworn portion of the first outer bending section becomes shorter as it extends toward the outer side of the electrode assembly.

9. In Paragraph 1, A secondary battery having a case diameter of 40 mm to 50 mm.

10. In Paragraph 1, A secondary battery in which the unoccupied portion of the second electrode is positioned in a direction opposite to the unoccupied portion of the first electrode.

11. In Paragraph 1, The unwound portion of the second electrode includes a second core-side cutting section, a second core-side bending section, a second outer-side bending section, and a second outer-side cutting section. The unworn portion of the second core-side bending section is bent in the centrifugal direction of the electrode assembly, a secondary battery.

12. In Paragraph 11, A secondary battery in which the unoccupied portion of the second outer bending section is bent in the centripetal direction of the electrode assembly.

13. In Paragraph 11, It further includes a second current collector plate electrically connected to the second electrode, and A secondary battery in which one end of the non-removable portion is cut so that the non-removable portion of the second core-side cutting section is spaced apart from the second current collector plate.

14. In Paragraph 13, A secondary battery, wherein the length of the second core-side cutting section corresponds to a length wound 1 to 3 times from the inner diameter of the electrode assembly.

15. In Paragraph 11, A secondary battery in which one end of the blank portion is cut so that the blank portion of the second outer side cutting section is spaced apart from the case.

16. In Paragraph 15, A secondary battery, wherein the length of the second outer side cutting section corresponds to a length wound 1 to 3 times from the outer diameter of the electrode assembly.

17. In Paragraph 11, A secondary battery in which the length of the unwound portion of the second core-side bending section becomes shorter as it approaches the core-side of the electrode assembly.

18. In Paragraph 11, A secondary battery in which the length of the unworn portion of the second outer bending section becomes shorter as it approaches the outer side of the electrode assembly.

19. In Paragraph 11, A secondary battery in which the length of the first outer side cutting section and the length of the second outer side cutting section are different.

20. A step of forming an electrode assembly by winding the first electrode, the separator, and the second electrode; and The method includes the step of inserting the above electrode assembly into a case, The unwound portion of the first electrode includes a first core-side cutting section, a first core-side bending section, a first outer-side bending section, and a first outer-side cutting section. A method for manufacturing a secondary battery, wherein the unworn portion of the first core-side bending section is bent in the centrifugal direction of the electrode assembly.

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