Secondary battery

Abstract

A secondary battery includes: an electrode assembly including a first electrode plate, a second electrode plate, and a separator; a case accommodating the electrode assembly and having an opening; a cap plate coupled to and sealing the opening of the housing; a first terminal plate and a second terminal plate on the cap plate and electrically connected to the first electrode plate and the second electrode plate, respectively; and a first current collector plate and a second current collector plate between the first terminal plate and the electrode assembly and between the second terminal plate and the electrode assembly, respectively, to electrically connect the first terminal plate and the second terminal plate to the first electrode plate and the second electrode plate. The first current collector plate and the second current collector plate respectively have a first protrusion and a second protrusion passing through the cap plate and connected to the first terminal plate and the second terminal plate.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2023-0128755 filed in the Korean Intellectual Property Office on September 26, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] Aspects of embodiments of the present disclosure are directed to a secondary battery. Background Art

[0004] Unlike primary batteries, secondary batteries are designed to be rechargeable. Among various secondary batteries, low-capacity batteries including battery cells (e.g., single battery cells) in the form of groups can be used in small portable electronic devices (such as smart phones and digital cameras), and high-capacity battery modules including tens to hundreds of battery groups connected to each other can be used as a power source for, for example, driving a motor of a hybrid vehicle or an electric vehicle.

[0005] A rechargeable secondary battery generally includes an electrode assembly in which a separator is interposed between a positive electrode plate and a negative electrode plate; a current collector plate electrically connected to the electrode assembly; a terminal electrically connected to the current collector plate; a case that houses the electrode assembly and the current collector plate; and a cover plate that seals (or shields) the case and through which the terminal passes to be connected to an external device.

[0006] The terminal plate and the current collector plate may be fixed by rivets. For example, the terminal plate and the current collector plate may be fixed by using rivets, and then the upper and lower portions of the rivets may be welded. In addition, in some embodiments, the sub-plate connected to the electrode assembly may be fixed to the current collector plate by welding. That is, welding must be performed on each of the rivet portion and the sub-plate. As the number of welding points increases, more parts are required, and therefore, the defect rate increases, thereby increasing production costs and reducing productivity.

[0007] The above information disclosed in this Background section is provided as background for the present disclosure and to improve understanding of the background of the present disclosure. Therefore, it may include information that does not constitute related (or prior) technology. Summary of the invention

[0008] Aspects of embodiments of the present disclosure provide a secondary battery in which a current collector plate and a sub-plate are integrated with each other, and the current collector plate and a terminal plate are welded to each other to reduce costs and improve productivity.

[0009] However, aspects and features of the present disclosure are not limited to those described above, and other aspects and features not mentioned can be clearly understood by those skilled in the art from the description of the present disclosure provided below.

[0010] According to an embodiment of the present disclosure, a secondary battery includes: an electrode assembly including a first electrode plate, a second electrode plate and a separator; a housing accommodating the electrode assembly and having an opening; a cover plate coupled to and sealing the opening of the housing; a first terminal plate on the cover plate and electrically connected to the first electrode plate; and a first current collector plate between the first terminal plate and the electrode assembly to electrically connect the first terminal plate to the first electrode plate. The first current collector plate has a first protrusion that passes through the cover plate and is connected to the first terminal plate.

[0011] The first current collector plate includes a first terminal connection portion connected to the first terminal plate and a first electrode connection portion extending from the first terminal connection portion and coupled to the first electrode plate.

[0012] The first terminal connection portion and the first electrode connection portion may be integrated with each other.

[0013] The first protrusion may be at a central region of the first terminal connecting portion, and may protrude toward the cap plate.

[0014] The first current collector plate may further include a first connection portion vertically bent from the first terminal connection portion toward the electrode assembly and extending to the first electrode connection portion and between the first terminal connection portion and the first electrode connection portion.

[0015] The first connection portion may have an inclined surface at a portion extending from the first terminal connection portion to the first electrode connection portion.

[0016] In the first connection portion, a thickness at one side of the first terminal connection portion and a thickness at one side of the first electrode connection portion may be different from each other.

[0017] The first terminal connection portion may have a thickness greater than a thickness of the first electrode connection portion.

[0018] The first protrusion may be in contact with a bottom surface of the first terminal plate.

[0019] The first protrusion may be laser welded to a bottom surface of the first terminal plate.

[0020] The first protrusion may protrude in an elliptical shape in a plan view.

[0021] The cover plate may have a first through hole through which the first protrusion passes, and a shape of the first through hole may correspond to a shape of the first protrusion.

[0022] The first through hole may have a size greater than or equal to a size of the first protrusion.

[0023] A portion of the first electrode connecting portion in the longitudinal direction may be bent to protrude outside the electrode assembly, and two regions of the first electrode connecting portion at both sides of the protruding portion may be bent toward the electrode assembly with respect to the protruding portion.

[0024] The secondary battery may further include a first sub tab coupled to the first electrode connection part and connected to the first electrode plate.

[0025] The first electrode connection portion and the first sub tab may be laser welded from an outer surface of the first electrode connection portion.

[0026] Welding regions at which the first electrode connecting parts are laser welded may be spaced apart in the longitudinal direction.

[0027] The welding region where the laser welding is performed may be at both sides of the protruding portion of the first electrode connecting part.

[0028] When the electrode assembly is in a stacked shape, the laser welding direction may be perpendicular to an arrangement direction of the first electrode plates.

[0029] The secondary battery may further include a first upper insulating member between the first terminal connection part and the first terminal plate.

[0030] The secondary battery may further include a first lower insulating member between the first terminal connection part and the cap plate.

[0031] The secondary battery may further include: a second terminal plate on the cap plate and electrically connected to the second electrode plate; and a second current collector plate between the second terminal plate and the electrode assembly to electrically connect the second terminal plate to the second electrode plate, and a thickness of the first current collector plate may be greater than or equal to a thickness of the second current collector plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification. The accompanying drawings illustrate embodiments of the present disclosure and together with the description explain various aspects and features of the present disclosure. In the drawings:

[0033] Figure 1 is a perspective view of a secondary battery according to an embodiment;

[0034] Figure 2 yes Figure 1 An exploded perspective view of a secondary battery shown in FIG.

[0035] Figure 3Aand Figure 3B According to the embodiments Figure 1 A perspective view and a front view of a current collector plate of a secondary battery shown in FIG.

[0036] Figure 4A and Figure 4B The terminal board and Figure 3A and Figure 3B A perspective view of the current collector plate shown in FIG. Figure 4A A cross-sectional view taken along line 4b-4b in FIG.

[0037] FIG. 5A to FIG. 5C is a front view of the structure of a current collector plate according to various embodiments; and

[0038] Figure 6 It is shown FIG. 5A to FIG. 5C A graph showing the temperature variation at different positions of the current collector plate is shown in FIG. DETAILED DESCRIPTION

[0039] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The terms used in this specification and the claims are not limited to their dictionary meanings, and are only used to achieve a clear and consistent understanding of the embodiments of the present disclosure. Accordingly, it should be understood by those skilled in the art that the following description of the embodiments of the present disclosure is provided for illustrative purposes and is not intended to limit the purpose of the present disclosure as defined by the attached claims and their equivalents. Therefore, since the embodiments described in this specification and the configurations shown in the accompanying drawings are an embodiment of the present disclosure and do not represent all technical ideas of the present disclosure, it should be understood that various equivalents and modifications that can replace them may exist when submitting this application.

[0040] That is, the present disclosure may be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0041] It will be understood that when an element or layer is referred to as being "on," "connected to," or "coupled to" another element or layer, it may be directly on, directly connected to, or coupled to the other element or layer, or there may also be one or more intervening elements or layers. When an element or layer is referred to as being "directly on," "directly connected to," or "directly coupled to" another element or layer, there may be no intervening elements or layers. For example, when a first element is described as being "coupled to" or "connected to" a second element, the first element may be directly coupled to or connected to the second element, or the first element may be indirectly coupled to or connected to the second element via one or more intervening elements.

[0042] In the drawings, for clear illustration, the sizes of various elements, layers, etc. may be exaggerated. The same reference numerals refer to the same elements. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. In addition, when describing the embodiments of the present disclosure, the use of "may" relates to "one or more embodiments of the present disclosure". Statements such as "at least one of..." and "any one of..." modify the entire column of elements after a column of elements, rather than modifying a single element in the column. For example, the statement "at least one of a, b, and c" represents only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c, or variations thereof. As used herein, the term "use" may be considered to be synonymous with the term "utilize". As used herein, the terms "substantially", "approximately" and similar terms are used as approximate terms rather than degree terms, and are intended to take into account the inherent variation of the measured or calculated values ​​recognized by those of ordinary skill in the art.

[0043] It will be understood that although the terms first, second, third, etc. can be used in this article to describe various elements, components, areas, layers and / or sections, these elements, components, areas, layers or sections should not be limited by these terms. These terms are used to distinguish one element, component, area, layer or section from another element, component, area, layer or section. Therefore, the first element, component, area, layer or section discussed below can be referred to as the second element, component, area, layer or section without departing from the teachings of the exemplary embodiments.

[0044] For ease of description, spatially relative terms (such as "below", "below", "down", "above", "on", etc.) may be used herein to describe the relationship between an element or feature and another element or feature as illustrated in the figure. It will be understood that spatially relative terms are intended to cover different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure is flipped, the element described as "below" or "below" other elements or features will then be oriented "above" or "on" other elements or features. Therefore, the term "below" can cover both above and below orientations. The device can be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein should be interpreted accordingly.

[0045] The terms used herein are for the purpose of describing the embodiments of the present disclosure and are not intended to limit the present disclosure. As used herein, the singular form "a" is intended to also include the plural form, unless the context clearly indicates otherwise. It will be further understood that when used in this specification, the terms "include" and / or "comprise" specify the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups thereof.

[0046] In addition, any numerical range disclosed and / or recorded herein is intended to include all sub-ranges of the same numerical precision contained in the recorded range. For example, the range of "1.0-10.0" is intended to include all sub-ranges between the recorded minimum value 1.0 and the recorded maximum value 10.0 (and including the recorded minimum value 1.0 and the recorded maximum value 10.0), that is, having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4-7.6. Any maximum numerical limit recorded herein is intended to include all lower numerical limits contained therein, and any minimum numerical limit recorded in this specification is intended to include all higher numerical limits contained therein. Accordingly, the applicant reserves the right to modify this specification (including claims) to explicitly record any sub-range contained in the range explicitly recorded herein.

[0047] In some embodiments, in this specification, reference to two comparison objects being "the same" means "the same or substantially the same". Therefore, substantial equivalence may include deviations that are considered low levels in the art, for example, deviations of less than 5%. In some embodiments, uniformity of a parameter over a region may refer to uniformity from an average perspective.

[0048] Figure 1 is a perspective view of a secondary battery according to an embodiment, Figure 2 yes Figure 1 An exploded perspective view of a secondary battery shown in FIG. Figure 3A and Figure 3B According to the embodiments Figure 1 A perspective view and a front view of a current collector plate of a secondary battery are shown in FIG. Figure 4A and Figure 4B The terminal board and Figure 3A and Figure 3B A perspective view of the current collector plate shown in FIG. Figure 4A A cross-sectional view taken along line 4b-4b in FIG.

[0049] refer to Figures 1 to 4B , a secondary battery 100 according to an embodiment of the present disclosure may include an electrode assembly 110 , current collector plates 120 , 130 , a case 150 , and a cap assembly 160 .

[0050] The electrode assembly 110 may be provided by stacking a plurality of first electrode plates, a diaphragm, and a second electrode plate (e.g., a stack of a plurality of first electrode plates, diaphragms, and second electrode plates) each having a thin plate or film shape. In some embodiments, the electrode assembly 110 may have a rectangular parallelepiped shape, in which a rectangular first electrode plate, a rectangular diaphragm, and a rectangular second electrode plate are stacked sequentially. In some embodiments, the electrode assembly 110 may have a rectangular parallelepiped shape, in which the diaphragm is attached to both side surfaces of the first electrode plate, the first electrode plate and the diaphragm are folded together in a substantially "Z" or "S" shape, and the second electrode plate is assembled between the two sides of the folding area having a zigzag shape to be stacked. In a stacked electrode assembly, when the electrode assembly 110 having a rectangular parallelepiped shape is coupled to a housing 150 having a substantially rectangular internal space (or is accommodated in the housing 150), there is almost no gap between the electrode assembly 110 and the housing 150, so the battery can exhibit a significantly increased capacity. In some embodiments, the first electrode plate may have a first polarity, for example, it may be used as a positive electrode, and the second electrode plate may have a second polarity, for example, it may be used as a negative electrode. In some embodiments, the first electrode plate and the second electrode plate may have different polarities depending on the choice of those skilled in the art (for example, it may be a polarity opposite to the above polarity).

[0051] The first electrode plate may include a first electrode current collector made of a metal foil (such as an aluminum foil), and may have a first electrode coating portion formed by coating a first electrode active material (such as a transition metal oxide) on the metal foil and a first electrode uncoated portion that is not coated with the first electrode active material. The first electrode uncoated portion may provide a path for current flow between the first electrode plate and the outside. In some embodiments, if the first electrode plates are stacked, the first electrode uncoated portions may be arranged to overlap at the same position, thereby providing a multi-joint structure. The first electrode uncoated portion may protrude to one side of the electrode assembly 110 (or may protrude from one side of the electrode assembly 110). In some embodiments, a plurality of first electrode uncoated portions may be welded to each other to provide a first current collector tab. The first electrode uncoated portion may be aligned to one side of the electrode assembly 110 to protrude from that side.

[0052] The second electrode plate may include a second electrode current collector made of a metal foil (such as copper, copper alloy, nickel or nickel alloy), and may have a second electrode coating portion formed by coating a second electrode active material (such as graphite or carbon) on the metal foil and a second electrode uncoated portion that is not coated with the second electrode active material. The second electrode uncoated portion may provide a path for current flow between the second electrode plate and the outside. In some embodiments, if the second electrode plates are stacked, the second electrode uncoated portions may also be arranged to overlap at the same position, thereby providing a multi-joint structure. The second electrode uncoated portion may be provided to protrude to the other side (e.g., the opposite side) of the electrode assembly 110. In some embodiments, a plurality of first electrode uncoated portions may be welded to each other to provide a second current collector tab.

[0053] The separator may be disposed between the first electrode plate and the second electrode plate to prevent a short circuit between them while enabling lithium ions to move between them. The separator may be made of polyethylene, polypropylene, or a composite film of polyethylene and polypropylene. However, the material of the separator is not limited. In some embodiments, the separator may be replaced with a solid electrolyte.

[0054] In some embodiments, after stacking a plurality of electrode plates, the electrode assembly 110 may be maintained in a stacked state by a separate insulating tape attached to a partial region thereof. In some embodiments, the insulating tape may allow the electrode assembly 110 to maintain its shape, so that the electrode assembly 110 is connected to the current collector plates 120, 130 in the correct position, and so that the structure of the electrode assembly is maintained in the structure of the final secondary battery.

[0055] In some embodiments, the electrode assembly 110 and the electrolyte may be substantially contained in the housing 150. The electrolyte may include an organic solvent such as ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), or dimethyl carbonate (DMC) and a lithium salt such as LiPF6 or LiBF4. In some embodiments, the electrolyte may be a liquid, a solid, or a gel.

[0056] The collector plates 120, 130 may include a first collector plate 120 electrically connected to the first electrode uncoated portion and a second collector plate 130 electrically connected to the second electrode uncoated portion. The first collector plate 120 may be made of a conductive material such as aluminum and may be electrically coupled to the first electrode uncoated portion protruding from one end of the electrode assembly 110 to be electrically connected to the first electrode plate. The first collector plate 120 may include a first terminal connection 121 and a first electrode connection 122. In some embodiments, the first terminal connection 121 and the first electrode connection 122 may be integral with each other. In some embodiments, the first terminal connection 121 and the first electrode connection 122 may have a structure designed to be capable of sheet metal production and injection mold production after laser cutting. A more detailed description of the collector plates 120, 130 will be provided below.

[0057] The housing 150 may have a hollow rectangular parallelepiped shape having at least one opening. For example, the housing 150 may have an opening defined in an upper surface or a side surface thereof. However, hereinafter, reference is made to Figure 2 An embodiment in which an opening is defined in the upper portion of the housing 150 is described. The electrode assembly 110 can be inserted into the housing 150 through the opening. The housing 150 can have a bottom, a pair of long sides, and a pair of short sides connecting the pair of long sides to each other (or extending between the pair of long sides), and the opening can be provided opposite to the bottom. The cover plate 161 can be coupled to the opening of the housing 150 to seal the housing 150. The inner surface of the housing 150 can be insulated to prevent an electrical short circuit from occurring therein. In some embodiments, one electrode of the electrode assembly 110 can be electrically connected to the housing 150 through the cover plate 161. In some embodiments, internal electrical short circuits can be prevented by insulating the interior of the housing 150. In some embodiments, the housing 150 can be made of a conductive metal (such as aluminum, an aluminum alloy, or nickel-plated steel) and can be manufactured by a deep drawing process or by a bending and welding process.

[0058] The cap assembly 160 may be coupled to an upper portion (e.g., an opening) of the housing 150. The cap assembly 160 may include a cap plate 161, an electrolyte injection hole 162 in the cap plate 161, a safety vent 163, a first terminal plate 1641, a second terminal plate 1642, a first upper insulating member 1651, a second upper insulating member 1652, a first coupling plate 1661, a second coupling plate 1662, a first lower insulating member 1671, and a second lower insulating member 1672.

[0059] The cover plate 161 may seal the opening of the housing 150 and may be made of the same material as that of the housing 150. The cover plate 161 may be provided as a thin plate having a flat plate shape. In some embodiments, the cover plate 161 may be coupled to the housing 150 by laser welding. In some embodiments, the cover plate 161 may be electrically independent (e.g., may be electrically floating), or in some embodiments, may be electrically connected to the first collector plate 120 or the second collector plate 130. In some embodiments, the cover plate 161 may have a first through hole 161a and a second through hole 161b, and the first protrusion 1211 of the first collector plate 120 and the second protrusion 1311 of the second collector plate 130 pass through the first through hole 161a and the second through hole 161b, respectively. The shapes of the first through hole 161a and the second through hole 161b may correspond to the shapes of the first protrusion 1211 and the second protrusion 1311, respectively. In some embodiments, the sizes of the first through hole 161a and the second through hole 161b may be respectively greater than or equal to the sizes of the first protrusion 1211 and the second protrusion 1311. For example, the first protrusion 1211 and the second protrusion 1311 may be respectively fitted into the first through hole 161a and the second through hole 161b or may respectively pass through the first through hole 161a and the second through hole 161b.

[0060] In some embodiments, an electrolyte injection hole 162 for injecting an electrolyte may be defined in the cap plate 161. The electrolyte may be injected into the case 150 through the electrolyte injection hole 162, and then, the electrolyte injection hole 162 may be sealed by a plug.

[0061] In some embodiments, the safety vent 163 may be disposed at a substantially center of the cap plate 161 and may have a relatively thin thickness compared to other areas of the cap plate 161. The safety vent 163 may prevent the secondary battery 100 according to an embodiment of the present disclosure from rupturing and exploding if the pressure inside the housing 150 is higher than a reference (or set) rupture pressure.

[0062] The first terminal plate 1641 and the second terminal plate 1642 may be electrically connected to the first electrode plate and the second electrode plate of the electrode assembly 110 by using (e.g., through) the first current collector plate 120 and the second current collector plate 130, respectively. In some embodiments, the first terminal plate 1641 and the second terminal plate 1642 may be connected to the first protrusion 1211 and the second protrusion 1311, respectively, and the first protrusion 1212 and the second protrusion 1311 protrude through the first through hole 161a and the second through hole 161b in the cap plate 161. In some embodiments, the first terminal plate 1641 may be coupled to the first protrusion 1211 provided on the first terminal connection part 121, and may be electrically connected to the first electrode plate. In some embodiments, the second terminal plate 1642 may be coupled to the second protrusion 1311 provided on the second terminal connection part 131, and may be electrically connected to the second electrode plate. In some embodiments, as described above, the first terminal plate 1641 and the second terminal plate 1642 may be fixed to the top surfaces of the first protrusion 1211 and the third protrusion 1311, respectively, by welding. In some embodiments, the first terminal plate 1641 and the second terminal plate 1642 may be directly coupled without using rivets.

[0063] The first upper insulating member 1651 and the second upper insulating member 165 may be disposed between the first terminal plate 1641 and the cap plate 161 and between the second terminal plate 1642 and the cap plate 161, respectively. The first upper insulating member 1651 and the second upper insulating member 1652 may be disposed to surround the outer sides of the first terminal plate 1641 and the second terminal plate 1642, respectively, and may be made of an insulating material. In some embodiments, the first upper insulating member 1651 and the second upper insulating member 1652 may seal the gap between the first terminal plate 1641 and the cap plate 161 and the gap between the second terminal plate 1642 and the cap plate 161, respectively. Each of the first upper insulating member 1651 and the second upper insulating member 1652 may prevent external moisture from penetrating into the secondary battery 100 and / or may prevent the electrolyte contained in the secondary battery 100 from leaking to the outside.

[0064] The first coupling plate 1661 and the second coupling plate 1662 may be disposed between the cap plate 161 and the first terminal plate 1641 and between the cap plate 161 and the second terminal plate 1642, respectively. Each of the first coupling plate 1661 and the second coupling plate 1662 may be made of a conductive material or an insulating material. In some embodiments, the first coupling plate 1661 disposed below the first terminal plate 1641 may be made of a conductive material, and the second coupling plate 1662 disposed below the second terminal plate 1642 may be made of an insulating material. In some embodiments, the first terminal plate 1641 may have the same polarity as the cap plate 161. In some embodiments, when each of the first coupling plate 1661 and the second coupling plate 1662 is made of an insulating material, each of the first terminal plate 1641 and the second terminal plate 1642 may be electrically separated (or electrically isolated) from the cap plate 161.

[0065] First and second lower insulating members 1671 and 1672 may be disposed between the first and second collector plates 120 and 130 and the cap plate 161 , respectively, to electrically insulate the first and second collector plates 120 and 130 from the cap plate 161 .

[0066] refer to FIG. 3A to FIG. 4B , the first terminal connection portion 121 of the first current collector plate 120 may be disposed at (or on) an upper portion of the electrode assembly 110 and may be disposed parallel to the cap plate 161. In some embodiments, the first terminal connection portion 121 may be disposed between the electrode assembly 110 and the cap plate 161. The first terminal connection portion 121 may include a first protrusion 1211 for connecting to the first terminal plate 1641. In some embodiments, the first protrusion 1211 may pass through the cap plate 161 and may be connected to the first terminal plate 1641. For example, the first protrusion 1211 may pass through the cap plate 161 to contact the bottom surface of the first terminal plate 1641. In some embodiments, the first terminal plate 1641 may be laser welded to the first protrusion 1211 at its bottom surface. In some embodiments, as Figure 3A and Figure 4B As illustrated, laser welding may be performed along a first welding line 1211a on (or from) the bottom surface of the first protrusion 1211. The first welding line 1211a may be provided as a long line based on the longitudinal direction of the first protrusion 1211 and may be formed of a plurality of lines.

[0067] In some embodiments, the first protrusion 1211 may be provided at a central area of ​​the first terminal connection portion 121 to protrude in the direction of the cover plate 161 (or toward the cover plate 161). In some embodiments, the first protrusion 1211 may protrude in an elliptical shape in a plan view. For example, the first protrusion 1211 may protrude in a horseshoe shape. However, the embodiments of the present disclosure are not limited thereto, and in various embodiments, the first protrusion 1211 may protrude in a circular, prismatic, or the like. The thickness of the first terminal connection portion 121 may be greater than the thickness of the first electrode connection portion 122, which will be described later.

[0068] The first electrode connection portion 122 may extend from the first terminal connection portion 121 and may be electrically connected to the first electrode plate. In some embodiments, the first electrode connection portion 122 may be bent in a direction perpendicular to the first terminal connection portion 121 and may extend along one surface of the electrode assembly 110. The first electrode connection portion 122 may be electrically connected to the first electrode uncoated portion of the electrode assembly 110 and may have the same first polarity as the first electrode uncoated portion. When the first current collector plate 120 has the first polarity, the first terminal plate 1641 may also have the first polarity.

[0069] In some embodiments, the first current collector plate 120 may further include a first connection portion 123, which is bent vertically in a direction from the first terminal connection portion 121 toward the electrode assembly 110 to continue to the first electrode connection portion 122, and is disposed between the first terminal connection portion 121 and the first electrode connection portion 122. In some embodiments, as described above, the first terminal connection portion 121 and the first electrode connection portion 122 may have different thicknesses. In some embodiments, in the first connection portion 123 that connects the first terminal connection portion 121 to the first electrode connection portion 122, the thickness at one side of the first terminal connection portion 121 and the thickness at one side of the first electrode connection portion 122 may be different from each other. Thus, an inclined surface may be provided on a portion of the first connection portion 123 connected between the first terminal connection portion 121 and the first electrode connection portion 122. Although it is described that the first terminal connection portion 121 and the first electrode connection portion 122 are bent vertically, the embodiments of the present disclosure are not limited thereto. In other embodiments, the first connection portion 123 may connect the first terminal connection portion 121 to the first electrode connection portion 122 at an inclined angle (eg, at a predetermined inclined angle).

[0070] The first electrode connection portion 122 may be bent so that a portion of the first electrode connection portion 122 in the longitudinal direction protrudes outside the electrode assembly 110, and two regions of the first electrode connection portion 122 located at both sides of the protruding portion are bent toward the electrode assembly 110 based on the protruding portion. In some embodiments, the first electrode connection portion 122 may have a first region 122a extending from the first terminal connection portion 121 and a second region 122b extending from the first region 122a to correspond to the insulating tape of the electrode assembly 110. In some embodiments, the first region 122a may be bent toward the electrode assembly 110 relative to the second region 122b. The first electrode connection portion 122 may be configured so that the first region 122a is symmetrical relative to the second region 122b in the longitudinal direction. In some embodiments, the second region 122b is disposed at the approximate center of the first region 122a, and the first region 122a may be connected to the upper and lower portions (or upper and lower ends) of the second region 122b. In some embodiments, in the first electrode connection portion 122, the first terminal connection portion 121 and the first region 122a may be connected by the first connection portion 123. In some embodiments, the first electrode connection portion 122 may be provided to be symmetrical with respect to the second region 122b from a portion where the thickness at one side of the first electrode connection portion 122 is thin to the first region 122a.

[0071] In some embodiments, the first electrode connection portion 122 may be provided with a first sub-tab 1221 and may be electrically connected to the first electrode plate. The first sub-tab 1221 may be a portion that is in direct contact with the uncoated portion of the first electrode and may be disposed on the first region 122a of the first electrode connection portion 122. In some embodiments, the first sub-tab 1221 may be disposed symmetrically with respect to the second region 122b of the first electrode connection portion 122 in the longitudinal direction.

[0072] The first electrode connection portion 122 and the first sub-tab 1221 may be laser welded on the outer surface of the first electrode connection portion 122 (or from the outer surface of the first electrode connection portion 122). In the first electrode connection portion 122, the laser welded welding regions 122c may be separated (or separated or spaced apart) in the longitudinal direction. The welding regions 122c to be laser welded may be on both sides of the protruding portion of the first electrode connection portion 122. In some embodiments, when the electrode assembly 110 is provided in a stacked form, the laser welding advancing (or moving) direction may be perpendicular to the arrangement direction of the first electrode plate.

[0073] In some embodiments, a plurality of welding holes may be defined in each welding region 122c of the first region 122a of the first electrode connection portion 122. A plurality of welding holes may be provided, and may be arranged along the longitudinal direction of the first electrode connection portion 122. Each welding hole may extend in a horizontal direction perpendicular to the longitudinal direction. In some embodiments, the welding holes defined in the welding region 122c of the first region 122a may extend in a direction substantially perpendicular to the first electrode uncoated portion of the electrode assembly 110.

[0074] In some embodiments, a portion of the adjacent surface of the first sub-tab 1221 disposed inside the first electrode connection portion 122 may be exposed through the welding hole of the first electrode connection portion 122. Thus, when a welding beam is irradiated from the outside, the welding beam may pass through the welding hole to reach the adjacent surface (e.g., exposed surface) of the first sub-tab 1221. Since the first sub-tab 1221 is in contact with the first electrode uncoated portion of the electrode assembly 110, the first electrode connection portion 122 and the first electrode uncoated portion may be connected to each other.

[0075] The second current collector plate 130 may be made of a conductive material such as nickel, and may be in contact with the second electrode uncoated portion protruding to the other end of the electrode assembly 110 (or protruding from the other end of the electrode assembly 110) to be electrically connected to the second electrode plate. The second current collector plate 130 may have a second terminal connection portion 131 provided with a second protrusion 1311, a second electrode connection portion 132, and a second connection portion 133. In some embodiments, the second current collector plate 130 may be laser welded to the second terminal plate 1642 along a second welding line 1311a on the rear surface of the second protrusion 1311. In some embodiments, the second electrode connection portion 132 may be provided with a second sub-tab 1321. The second electrode connection portion 132 may have a first region 132a and a second region 132b. In some embodiments, the second region 132b is disposed at the approximate center of the first region 132a, and the first region 132a may be connected to the upper and lower portions of the second region 132b. The second electrode connection portion 132 and the second sub-tab 1321 may be welded at the second welding region 132c of the first region 132a of the second electrode connection portion 132. In some embodiments, the second upper insulating member 1652 may be interposed between the second terminal connection portion 131 and the second terminal plate 1642, and the second lower insulating member 1672 may be interposed between the second terminal connection portion 131 and the cap plate 161. Since the shape of the second collector plate 130 is the same as that of the first collector plate 120, a repeated description thereof will be omitted. However, in some embodiments, the thickness of the first collector plate 120 may be greater than or the same as that of the second collector plate 130.

[0076] FIG. 5A to FIG. 5C is a front view of the structure of the current collector plate according to various embodiments, Figure 6 yes FIG. 5A to FIG. 5C FIG. 4 is a graph showing the temperature variation at each location in various embodiments of the current collector plate.

[0077] Figure 5A A comparative example of a terminal plate and a current collector plate connected by rivets is shown. Figure 5B An embodiment showing a direct connection between the terminal plate and the integrated current collector plate (eg, the terminal connection portion and the electrode connection portion have the same thickness) is shown. Figure 5C An embodiment is shown in which the terminal plate and the integrated current collector plate are directly coupled (eg, the terminal connection portion and the electrode connection portion have different thicknesses).

[0078] Figure 5A A rivet structure according to the related art is shown, in which the collector plate and the sub-plate are welded together, and the terminal plate and the collector plate are connected by rivets. In some embodiments, the thickness TA1 of the collector plate and the thickness TA2 of the sub-plate may be different from each other. When connected in a riveted manner, the terminal plate and the collector plate may be fixed by rivets, and then the upper and lower parts of the rivet may be welded. The terminal connection portion and the electrode connection portion of the collector plate may be provided as separate components to weld the two parts by welding, and therefore, additional welding points may occur. As a result, the number of welding points and components increases, which may be inefficient in terms of production time and cost.

[0079] Figure 5B An integrated current collector according to an embodiment of the present disclosure is shown. Figure 5C FIG. 2 shows an integrated current collector according to another embodiment of the present disclosure. Figure 5B In the embodiment shown in FIG. 1 , the thickness TB1 of the terminal connection portion and the thickness TB2 of the electrode connection portion may be the same. Figure 5C In the embodiment shown in FIG. 1 , the thickness TC1 of the terminal connection portion and the thickness TC2 of the electrode connection portion may be different from each other. Figure 5B and Figure 5C In the embodiment shown in , product production time and cost can be reduced by reducing the number of welding points while fixing the terminal plate and the integrated current collector without using rivets. By reducing or minimizing the number of welding points, the defect rate is reduced. If welding is not performed properly, heat and resistance increase significantly and affect the life of the battery cell, so the number of welding points is reduced. In some embodiments, since welding is expensive, costs can be reduced when the number of welding points is reduced. Therefore, in Figure 5B and Figure 5CIn the embodiment shown in FIG. 1 , by constructing the terminal connection portion and the electrode connection portion as an integral component, unnecessary processes (such as welding of separate components) can be omitted, and also because the shape of the metal sheet and the shape of the mold are taken into consideration, the electrode plate can be provided according to convenience and manufacturing environment. In some embodiments, for example, in Figure 5B and Figure 5C In the embodiment shown in Figure 5A Compared with the area of ​​the terminal plate of the comparative example shown in FIG, the area of ​​the terminal plate can be larger and the heat distribution effect can be improved. In some embodiments, the temperature of the bus bar connected to the terminal plate can be reduced, and the bus bar can be easily attached due to its large area.

[0080] In some embodiments, for example, Figure 5C In the embodiment shown in FIG. 1 , since the protrusion of the integrated current collector and the terminal plate are fixed without using rivets, the rigidity is similar to that of the embodiment shown in FIG. Figure 5A Compared with the thickness of the terminal-side current collector in the comparative example shown in , the thickness of the terminal-side current collector can be reduced, which is beneficial in reducing material costs.

[0081] Table 1

[0082]

[0083]

[0084] Table 1 above shows the maximum temperatures of the positive electrode plate and the negative electrode plate (eg, the terminal connection portion and the electrode connection portion) in the electrode assembly at a specific current value over a period of time. Figure 6 is a graph showing the change in maximum temperature. Figure 6 see, Figure 5C The maximum temperature of the embodiment shown is Figure 5A The maximum temperature of the comparative example shown is similar, and the temperature at all locations is lower than Figure 5B That is, it can be seen that in the secondary battery according to the embodiment of the present disclosure, for example Figure 5C In the current collector plate structure shown in , the thickness of the terminal connection portion is reliable to ensure rigidity and heat dissipation performance.

[0085] According to an embodiment of the present disclosure, a raised area for welding can be provided on a current collector plate integrated with a sub-plate, and the current collector plate and the terminal plate can be welded without using rivets to minimize welding points, thereby reducing product production time and cost and improving productivity.

[0086] According to the embodiment of the present disclosure, since the area of ​​the terminal plate is increased compared with the existing example, the bus bar can be easily attached, and the heat distribution effect can be improved to reduce the temperature of the bus bar.

[0087] However, aspects and features of the present disclosure are not limited to the above-mentioned aspects and features, and other aspects and features not mentioned herein may be clearly understood by those skilled in the art from the description of the present disclosure.

[0088] The above embodiments are merely embodiments of secondary batteries, and therefore, the present disclosure is not limited to the foregoing embodiments. In addition, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present disclosure as defined by the claims and their equivalents. In other words, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the present disclosure as defined by the claims and their equivalents.

Claims

1. A secondary battery comprising: An electrode assembly, comprising a first electrode plate, a second electrode plate and a separator; a housing accommodating the electrode assembly and having an opening; a cover plate coupled to and sealing the opening of the housing; a first terminal plate disposed on the cap plate and electrically connected to the first electrode plate; as well as a first current collector plate between the first terminal plate and the electrode assembly to electrically connect the first terminal plate to the first electrode plate, The first current collector plate has a first protrusion that passes through the cap plate and is connected to the first terminal plate.

2. The secondary battery according to claim 1, wherein the first current collector plate comprises: a first terminal connecting portion connected to the first terminal plate; and A first electrode connecting portion extends from the first terminal connecting portion and is coupled to the first electrode plate. 3 . The secondary battery according to claim 2 , wherein the first terminal connection portion and the first electrode connection portion are integrated with each other. 4 . The secondary battery according to claim 2 , wherein the first protrusion is at a central area of ​​the first terminal connecting part and protrudes toward the cap plate. 5 . The secondary battery according to claim 2 , wherein the first current collector plate further comprises a first connection portion vertically bent from the first terminal connection portion toward the electrode assembly and extending to the first electrode connection portion, and between the first terminal connection portion and the first electrode connection portion. 6 . The secondary battery according to claim 5 , wherein the first connection portion has an inclined surface at a portion extending from the first terminal connection portion to the first electrode connection portion. 7 . The secondary battery according to claim 5 , wherein in the first connection portion, a thickness at one side of the first terminal connection portion and a thickness at one side of the first electrode connection portion are different from each other. 8 . The secondary battery according to claim 2 , wherein a thickness of the first terminal connection part is greater than a thickness of the first electrode connection part. 9 . The secondary battery according to claim 1 , wherein the first protrusion is in contact with a bottom surface of the first terminal plate. 10 . The secondary battery according to claim 1 , wherein the first protrusion is laser welded to a bottom surface of the first terminal plate. 11 . The secondary battery according to claim 1 , wherein the first protrusion protrudes in an elliptical shape in a plan view.

12. The secondary battery according to claim 1 or 2, wherein the cap plate has a first through hole, the first protrusion passes through the first through hole, and The shape of the first through hole corresponds to the shape of the first protrusion. 13 . The secondary battery according to claim 12 , wherein the first through hole has a size greater than or equal to a size of the first protrusion.

14. The secondary battery according to claim 2, wherein a portion of the first electrode connecting portion in a longitudinal direction is bent to protrude outside the electrode assembly, and Two regions of the first electrode connecting portion located at both sides of the protruding portion are bent toward the electrode assembly with respect to the protruding portion.

15. The secondary battery according to claim 14, further comprising: A first sub tab is coupled to the first electrode connecting part and connected to the first electrode plate. 16 . The secondary battery according to claim 15 , wherein the first electrode connection part and the first sub tab are laser welded from an outer surface of the first electrode connection part. 17 . The secondary battery according to claim 16 , wherein the first electrode connecting parts are separated in the longitudinal direction by welding regions where the laser welding is performed. 18 . The secondary battery according to claim 17 , wherein the welding region where the laser welding is performed is on both sides of the protruding portion of the first electrode connecting part. 19 . The secondary battery according to claim 16 , wherein when the electrode assembly is in a stacked shape, a laser welding direction is perpendicular to an arrangement direction of the first electrode plates. 20 . The secondary battery according to claim 2 , further comprising a first upper insulating member between the first terminal connection part and the first terminal plate. 21 . The secondary battery according to claim 2 , further comprising a first lower insulating member between the first terminal connection part and the cap plate.

22. The secondary battery according to claim 1, further comprising: a second terminal plate on the cap plate and electrically connected to the second electrode plate; and a second current collector plate between the second terminal plate and the electrode assembly to electrically connect the second terminal plate to the second electrode plate, The first current collector plate has a thickness greater than or equal to a thickness of the second current collector plate.

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