Current collector and battery cell, battery pack and vehicle including same

Abstract

A battery cell according to one embodiment of the present invention includes: an electrode assembly in which a first electrode, a second electrode and a separator interposed therebetween are wound with a winding axis as the center thereof to define a core and the outer circumferential surface thereof, the first electrode including a first uncoated portion provided at an end of a long side thereof in the winding direction and exposed to the outside of the separator without being coated with an active material layer, and at least a portion of the first uncoated portion itself being used as an electrode tab; a battery housing including an opening on one side thereof and accommodating the electrode assembly through the opening; cell terminals passing through a surface located on the opposite side of the opening of the battery housing; and a current collector including an edge portion disposed on one side of the electrode assembly, first uncoated portion coupling portions, which extend inward from the edge portion, are welded to the first uncoated portion and are disposed at a separation of 180 degrees so as to face each other, terminal coupling portions spaced apart from the first uncoated portion coupling portions and welded to the cell terminals, and a bridge portion, which connects the edge portion and the terminal coupling portions and is located between the first uncoated portion coupling portions.

Description

Current collector and battery cells, battery packs, and automobiles including the same

[0001] The present invention relates to a current collector and a battery cell, battery pack, and automobile including the same.

[0002] This application is a priority claim application for Korean Patent Application No. 10-2025-0013882 filed on February 4, 2025, and all contents disclosed in the specification of said application are incorporated into this application by reference.

[0003] Secondary batteries, which possess electrical characteristics such as high energy density and high applicability across product groups, are widely applied not only to portable devices but also to electric vehicles (EVs) or hybrid electric vehicles (HEVs) powered by electric sources. These secondary batteries are attracting attention as a new energy source for enhancing eco-friendliness and energy efficiency, as they possess not only the primary advantage of drastically reducing the use of fossil fuels but also the advantage of generating no by-products from energy use.

[0004] Currently, widely used types of secondary batteries include lithium-ion batteries, lithium-polymer batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and nickel-zinc batteries. The operating voltage of these unit secondary battery cells, or unit battery cells, is approximately 2.5V to 4.5V. Therefore, if a higher output voltage is required, multiple battery cells are connected in series to form a battery pack. Additionally, depending on the charge / discharge capacity required for the battery pack, multiple battery cells are connected in parallel to form a battery pack. Accordingly, the number of battery cells included in the battery pack can be varied depending on the required output voltage and / or charge / discharge capacity.

[0005] Meanwhile, in the manufacturing of conventional cylindrical battery cells, there were problems with concentricity and rotational deviations occurring during the supply of current collector plates. Consequently, welding mask tolerances occurred, leading to issues with welding quality.

[0006] One objective of the present invention is to secure tensile strength by increasing the welding area between the electrode assembly and the current collector.

[0007] In another aspect, the present invention has another objective of reducing the internal resistance of the cell by increasing the welding area between the electrode assembly and the current collector.

[0008] In addition, another objective of the present invention is to increase the degree of freedom at each location by expanding the slit area of ​​the current collector.

[0009] Furthermore, another objective of the present invention is to prevent deformation caused by heat by increasing the degrees of freedom at each location of the current collector.

[0010] However, the technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems will be clearly understood by a person skilled in the art from the description of the invention below.

[0011] A battery cell according to an embodiment of the present invention for solving the above-mentioned problem comprises: an electrode assembly in which a first electrode and a second electrode and a separator interposed between them are wound around a winding axis to define a core and an outer surface, wherein the first electrode includes a first uncoated portion exposed to the outside of the separator and in which an active material layer is not coated at the long end along the winding direction, and at least a portion of the first uncoated portion is used as an electrode tab itself; a battery housing configured to include an opening on one side and to receive the electrode assembly through the opening; and a cell terminal configured to pass through a surface located on the opposite side of the opening of the battery housing. The current collector includes a rim portion disposed on one side of the electrode assembly, a first non-bonded portion coupling portion that extends inwardly from the rim portion and is welded to the first non-bonded portion and is disposed at 180-degree intervals and faces each other, a terminal coupling portion that is spaced apart from the first non-bonded portion coupling portion and is welded to the cell terminal, and a bridge portion that connects the rim portion and the terminal coupling portion and is located between the first non-bonded portion coupling portions.

[0012] In one aspect of the present invention, the first non-reinforced portion coupling portion and the terminal coupling portion may be electrically connected by the edge portion.

[0013] In another aspect of the present invention, the rim portion, the first non-removable portion coupling portion, the terminal coupling portion, and the bridge portion of the current collector may be separated by a slit.

[0014] In another aspect of the present invention, the slit may include a first slit formed along the inner end of the edge portion; and a second slit separating the first non-reinforced portion from the terminal portion and the bridge portion.

[0015] In one aspect of the present invention, the first slit may be configured as at least one arc.

[0016] In another aspect of the present invention, the second slit may be extended in a direction parallel to an imaginary straight line passing through the center of the current collector.

[0017] In another aspect of the present invention, the second slits are provided in plurality, and the plurality of second slits may extend in directions parallel to each other.

[0018] Preferably, the second slit can be configured to cross the central region of the current collector.

[0019] In one aspect of the present invention, one end of the first slit and one end of the second slit may be connected to each other and formed integrally.

[0020] In another aspect of the present invention, the bridge portion may be configured so that its length can be extended.

[0021] In another aspect of the present invention, a plurality of welds are provided between the first non-welded portion and the current collector, and the angle between a virtual straight line passing through one end of the weld in the circumferential direction and the center of the current collector and a virtual straight line passing through the other end of the weld in the circumferential direction and the center of the current collector can be configured to be 120 degrees or more and 160 degrees or less.

[0022] In one aspect of the present invention, the ratio of the total area of ​​a plurality of welded portions to the total area of ​​the current collector may be formed to be 0.7 or more and 0.9 or less.

[0023] Meanwhile, the present invention provides a battery pack comprising at least one battery cell according to the above-described embodiment as a battery pack.

[0024] In addition, the present invention provides a vehicle comprising at least one battery pack according to the above-described embodiment.

[0025] Meanwhile, the present invention provides a current collector applied to a battery cell comprising: an electrode assembly having a first non-removable portion and a second non-removable portion; a battery housing that accommodates the electrode assembly through an opening formed on one side and is electrically connected to the second non-removable portion; and a cell terminal that is electrically connected to the first non-removable portion; the current collector comprising: a rim portion disposed on one side of the electrode assembly; a first non-removable portion coupling portion that extends inwardly from the rim portion and is welded to the first non-removable portion and is disposed at 180-degree intervals to face each other; a terminal coupling portion that is spaced apart from the first non-removable portion coupling portion and is welded to the cell terminal; and a bridge portion that connects the rim portion and the terminal coupling portion and is located between the first non-removable portion coupling portions.

[0026] According to the present invention, tensile strength can be secured by increasing the welding area between the electrode assembly and the current collector.

[0027] In another aspect, according to the present invention, the internal resistance of the cell can be reduced by increasing the welding area between the electrode assembly and the current collector.

[0028] In addition, according to the present invention, by expanding the slit area of ​​the current collector, the degree of freedom at each location can be increased.

[0029] Furthermore, according to the present invention, by increasing the degree of freedom at each location of the current collector, deformation caused by heat can be prevented.

[0030] However, the effects obtainable through the present invention are not limited to those described above, and other unmentioned technical effects will be clearly understood by a person skilled in the art from the description of the invention below.

[0031] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0032] FIG. 1 is a drawing showing the appearance of a battery cell according to one embodiment of the present invention.

[0033] FIG. 2 is a cross-sectional view showing the internal structure of a battery cell according to one embodiment of the present invention.

[0034] FIG. 3 is a drawing for explaining the electrode assembly, cell terminals, and current collector included in the battery cell of FIG. 1.

[0035] Figure 4 is a diagram illustrating the location where the cell terminal is connected to the current collector.

[0036] Figure 5 is a diagram illustrating a current collector included in a conventional battery cell.

[0037] FIG. 6 is a drawing for explaining a current collector according to one embodiment of the present invention.

[0038] FIG. 7 is a drawing for illustrating a current collector according to another embodiment of the present invention.

[0039] FIG. 8 is a drawing for illustrating a current collector according to another embodiment of the present invention.

[0040] FIG. 9 is a drawing for explaining the shape in which a current collector according to one embodiment of the present invention is welded to an electrode assembly.

[0041] FIG. 10 is a drawing for explaining a battery pack including the battery module of FIG. 1.

[0042] FIG. 11 is a drawing for explaining a vehicle including the battery pack of FIG. 10.

[0043] Hereinafter, preferred embodiments of the present invention will be described in detail 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, but should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention. Accordingly, 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; therefore, it should be understood that various equivalents and modifications capable of replacing them may exist at the time of filing this application.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0048] The fact that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0049] In addition, where it is stated that one component is "connected," "combined," or "connected" to another component, it should be understood that while the components may be directly connected or connected to each other, another component may be "interposed" between each component, or each component may be "connected," "combined," or "connected" through another component.

[0050] Throughout the specification, "A and / or B" means A, B, or A and B unless specifically stated otherwise, and "C to D" means C or more and D or less unless specifically stated otherwise.

[0051] For convenience of explanation, in this specification, the direction following the length direction of the winding axis of the electrode assembly (10) wound in a jelly roll shape is referred to as the axial direction. The direction surrounding the winding axis is referred to as the circumferential direction or the periphery direction. The direction approaching the winding axis or moving away from the winding axis is referred to as the radial direction. In particular, the direction approaching the winding axis is referred to as the centripetal direction, and the direction moving away from the winding axis is referred to as the centrifugal direction.

[0052]

[0053] FIG. 1 is a drawing showing the exterior of a battery cell (1) according to one embodiment of the present invention, and FIG. 2 is a cross-sectional view showing the internal structure of a battery cell (1) according to one embodiment of the present invention.

[0054] Referring to FIGS. 1 and 2, a battery cell (1) according to one embodiment of the present invention comprises an electrode assembly (10), a battery housing (20), a cell terminal (30), and a current collector (40). In addition to the components described above, the battery cell (1) may additionally include an insulating gasket (G2).

[0055]

[0056] The electrode assembly (10) comprises a first electrode having a first polarity, a second electrode having a second polarity, and a separator interposed between the first electrode and the second electrode. The first electrode is a positive or negative electrode, and the second electrode corresponds to an electrode having a polarity opposite to that of the first electrode.

[0057] The electrode assembly (10) may have, for example, a jelly-roll structure. That is, the electrode assembly (10) may be manufactured by winding a laminate formed by stacking a first electrode plate and a second electrode plate having a sheet shape at least once with a separator interposed between them in one direction with respect to the winding center (C). In this case, an additional separator may be provided on the outer surface of the electrode assembly (10) to insulate it from the battery housing (20). Any jelly-roll structure known in the art may be applied without limitation to the present invention.

[0058] The first electrode comprises a first electrode plate and a first electrode active material applied on one or both sides of the first electrode plate. A first uncoated portion (11) where the first electrode active material is not applied exists at one end in the width direction (direction parallel to the Z-axis) of the first electrode plate. The first uncoated portion (11) functioning as a first electrode tab will be referred to as the first uncoated portion (11) below. The first uncoated portion (11) is provided on the upper side in the height direction (direction parallel to the Z-axis) of the electrode assembly (10) housed within the battery housing (20). That is, the first electrode plate includes a first uncoated portion (11) that is exposed to the outside of the separator and where the active material layer is not coated at the long end, and a part of the first uncoated portion (11) is used as an electrode tab itself. The first uncoated portion (11) may be, for example, a positive electrode tab.

[0059] Meanwhile, at least a portion of the first bare portion (11) may include a plurality of segments divided along the winding direction of the electrode assembly (10). In this case, the plurality of segments may be folded along the radial direction of the electrode assembly (10). The folded plurality of segments may be overlapped in multiple layers. In this case, the first bare portion coupling portion (42), which will be described later, may be coupled to the area where the plurality of segments are overlapped in multiple layers.

[0060] The second electrode comprises a second electrode plate and a second electrode active material applied on one or both sides of the second electrode plate. At the other end of the second electrode plate in the width direction (direction parallel to the Z-axis), there exists a non-exposed portion where the second electrode active material is not applied. The non-exposed portion functioning as a second electrode tab is hereinafter referred to as the second non-exposed portion (12). The second non-exposed portion (12) is provided at the lower end in the height direction (direction parallel to the Z-axis) of the electrode assembly (10) housed within the battery housing (20). That is, the second electrode plate includes a second non-exposed portion (12) that is exposed to the outside of the separator and where the active material layer is not coated at the long end, and at least a portion of the second non-exposed portion (12) is used as an electrode tab itself. The second non-exposed portion (12) may be, for example, a negative electrode tab.

[0061] Meanwhile, at least a portion of the second non-removable portion (12) may include a plurality of segments divided along the winding direction of the electrode assembly (10). In this case, the plurality of segments may be bent along the radial direction of the electrode assembly (10). The bent plurality of segments may be overlapped in multiple layers. In this case, the second current collector may be coupled to the area where the plurality of segments are overlapped in multiple layers.

[0062] The first non-removable portion (11) and the second non-removable portion (12) extend in opposite directions along the height direction (a direction parallel to the Z-axis) of the battery cell (1). The first non-removable portion (11) extends toward the closed portion of the battery housing (20), and the second non-removable portion (12) extends toward the open portion of the battery housing (20).

[0063] In the present invention, the positive active material coated on the positive plate and the negative active material coated on the negative plate may be used without limitation as long as they are active materials known in the art.

[0064]

[0065] FIG. 3 is a drawing for explaining the electrode assembly (10), cell terminal (30), and current collector (40) included in the battery cell (1) of FIG. 1.

[0066] With reference to FIG. 3, the structure of the electrode assembly (10) will be described in more detail. In the following description, the first electrode among the first electrode and the second electrode described above will be used as an example, but the structure of the first electrode can be applied in the same way to the second electrode.

[0067] Preferably, the first unworn portion (11) may include a plurality of notched segments (11a). The plurality of segments (11a) form a plurality of groups, and the segments (11a) belonging to each group may have substantially the same height (length in the Z direction) and / or width (length in the X direction) and / or spacing pitch. The number of segments (11a) belonging to each group may be increased or decreased compared to that illustrated.

[0068] The unbent portions (11, 12) can be bent along the radial direction of the electrode assembly (10), for example, from the outer periphery side to the core side. When the unbent portions (11, 12) are bent, the segments adjacent in the radial direction overlap in multiple layers, and a bent surface is formed on the upper and lower parts of the electrode assembly (10).

[0069]

[0070] The battery housing (20) may be configured to include an opening on one side and to accommodate the electrode assembly (10) through the opening.

[0071] Specifically, the battery housing (20) is a roughly cylindrical receptacle with an opening formed at the bottom, and is made of a conductive material such as metal. For example, the material of the battery housing (20) may be steel, stainless steel, or nickel-plated steel. The upper surface located opposite the opening is referred to as the closed portion. The side wall and the closed portion of the battery housing (20) may be formed integrally. Alternatively, the side wall and the closed portion of the battery housing (20) may be provided separately from each other and joined together by welding or the like. The upper surface of the battery housing (20) (a surface parallel to the XY plane), that is, the outer surface (20a) of the closed portion, may have a roughly flat shape. The battery housing (20) accommodates the electrode assembly (10) through the opening formed at the bottom, and also accommodates the electrolyte.

[0072] The battery housing (20) is electrically connected to the electrode assembly (10). The battery housing (20) is electrically connected, for example, to the second non-electrode portion (12) of the electrode assembly (10). In this case, the battery housing (20) has the same polarity as the second non-electrode portion (12).

[0073]

[0074] FIG. 4 is a drawing for explaining the location where the cell terminal (30) is connected to the current collector (40).

[0075] Referring to FIGS. 1 to 4, the cell terminal (30) is made of a conductive metal material. For example, aluminum (Al) may be used as the material of the cell terminal (30). When the material of the cell terminal (30) is aluminum, processing can be made easier during riveting. The cell terminal (30) may use 10-series aluminum, which has relatively low electrical resistance.

[0076] The cell terminal (30) passes through the upper surface of the battery housing (20), that is, the surface located opposite the opening of the battery housing (20) (a surface parallel to the XY plane). The cell terminal (30) is electrically connected, for example, to the first non-electrode portion (11) of the electrode assembly (10). In this case, the cell terminal (30) has a first polarity. Accordingly, the cell terminal (30) can function as a first electrode terminal in the battery cell (1) of the present invention.

[0077] When the cell terminal (30) has a first polarity in this manner, the cell terminal (30) is electrically insulated from the battery housing (20) having a second polarity. Electrical insulation between the cell terminal (30) and the battery housing (20) can be realized in various ways. For example, insulation can be achieved by interposing an insulating gasket (G2) between the cell terminal (30) and the battery housing (20). Alternatively, insulation can be achieved by forming an insulating coating layer on a part of the cell terminal (30). Or, a method of structurally and firmly fixing the cell terminal (30) so that contact between the cell terminal (30) and the battery housing (20) is impossible may be applied. Or, multiple methods among those described above may be applied together. The cell terminal (30) may be rivet-bonded onto the closed portion of the battery housing (20).

[0078]

[0079] Referring to FIGS. 2 and 3, the connection between the bottom surface of the center region of the cell terminal (30) and the current collector (40) can be achieved, for example, by laser welding, spot welding, or ultrasonic welding.

[0080] The above welding can be performed by irradiating a laser through a hole formed in the center of the winding (C) of the electrode assembly (10) or by inserting a tool for ultrasonic welding or spot welding to form a welding bead on one side of the current collector (40) (the side facing the hole formed in the center of the winding (C) of the electrode assembly (10).

[0081] According to such a structure, the battery cell (1) according to one embodiment of the present invention can ensure smooth current flow at the joint portion between the current collector (40) and the cell terminal (30) when a large amount of current flows due to rapid charging, thereby bringing about effects such as shortening the charging time and reducing the amount of heat generated.

[0082] Meanwhile, the insulating gasket (G2) may be interposed between the outer surface (20a) of the closed portion of the battery housing (20) and the cell terminal (30). The insulating gasket (G2) may be made of, for example, a resin material having insulating and elastic properties. Accordingly, the insulating gasket (G2) can electrically insulate the battery housing (20) and the cell terminal (30).

[0083]

[0084] FIG. 5 is a drawing for explaining a current collector (40) included in a conventional battery cell (1).

[0085] Referring to FIG. 5, in a conventional battery cell (1), a first non-bonding part coupling part (42) that is coupled to a non-bonding part is arranged at intervals of approximately 90 degrees centered on the center of the current collector (40). Additionally, a bridge part (44) is arranged between the first non-bonding part coupling part (42). According to this structure, there are many welding points between the current collector (40) and the first non-bonding part (11), so the rotational deviation of concentricity increases when supplying the current collector (40). Consequently, the welding tolerance increases. Furthermore, according to the above conventional structure, the welding area between the current collector (40) and the first non-bonding part (11) is narrow, making it difficult to secure tensile strength and increasing the internal resistance of the cell.

[0086]

[0087] FIG. 6 is a drawing for explaining a current collector (40) according to one embodiment of the present invention.

[0088] Referring to FIGS. 4 and 6, the current collector (40) is coupled to the upper part of the electrode assembly (10). The current collector (40) is made of a conductive metal material and is connected to the first non-conductive part (11). More specifically, the current collector (40) can be welded to the upper part of the electrode assembly (10).

[0089] The current collector (40) is made of a conductive metal material. For example, aluminum (Al) may be used as the material of the current collector (40). For example, the current collector (40) may include Al1100-H14 material.

[0090] Meanwhile, the current collector (40) may include at least one current collector hole (H2). The current collector hole (H2) may function as a passage for the movement of the electrolyte.

[0091] The above-mentioned current collector (40) can be welded to a joining surface (folded surface) formed by bending the end of the first non-removable portion (11) in a direction parallel to the current collector (40). The bending direction of the first non-removable portion (11) may be the radial direction of the electrode assembly (10). The bending direction of the first non-removable portion (11) may be, for example, a direction toward the winding center (C) of the electrode assembly (10). When the first non-removable portion (11) has such a bent shape, the space occupied by the first non-removable portion (11) is reduced, which can lead to an improvement in energy density. In addition, due to the increase in the joining area between the first non-removable portion (11) and the current collector (40), an improvement in bonding strength and a reduction in contact resistance can be achieved.

[0092] Referring to FIGS. 7 through 9, at least a portion of the first non-removable portion (11) and / or the second non-removable portion (12) may include a plurality of segments (11a) divided along the winding direction of the electrode assembly (10). In this case, the plurality of segments may be folded along the radial direction of the electrode assembly (10). The folded plurality of segments may be superimposed in multiple layers. In this case, the first non-removable portion coupling portion (42) of the current collector (40), which will be described later, may be coupled to an area where the plurality of segments are superimposed in multiple layers.

[0093] The above current collector (40) electrically connects the first non-conductive portion (11) of the electrode assembly (10) and the cell terminal (30). The above current collector (40) is made of a conductive metal material.

[0094]

[0095] Referring again to FIG. 6, the current collector (40) includes a rim portion (41), a first non-reinforced portion coupling portion (42), a terminal coupling portion (43), and a bridge portion (44).

[0096] The above-mentioned rim portion (41) may be disposed on one side of the electrode assembly (10). For example, referring to FIG. 2, the rim portion (41) may be attached to the surface on which the first blank portion (11) is located among the two axial surfaces of the electrode assembly (10). The rim portion (41) may have a roughly rim shape with an empty space formed inside. However, the shape of the rim portion (41) is not limited thereto.

[0097] The first non-reinforced portion connecting part (42) extends inward from the edge portion (41) and is connected to the first non-reinforced portion (11). Preferably, the first non-reinforced portion connecting part (42) extends inward from the edge portion (41) and is welded to the first non-reinforced portion (11). At this time, a weld (W) may be provided between the first non-reinforced portion connecting part (42) and the first non-reinforced portion (11).

[0098] Preferably, a plurality of welded portions (W) may be provided between the first non-removable portion (11) and the current collector (40). For example, referring to FIG. 6, the first non-removable portion connecting portions (42) may be arranged at intervals of approximately 180 degrees relative to the center of the current collector (40). That is, the first non-removable portion connecting portions (42) may be arranged at intervals of approximately 180 degrees to face each other. In this case, the first non-removable portion connecting portions (42) may be composed of two along the circumferential direction. In such an embodiment, the first non-removable portion connecting portions (42) may be configured to face each other.

[0099] It is preferable that the connection between the current collector (40) and the first non-conforming part (11) be formed so as to overlap at least approximately 50% with the welding target area, which is a section where the number of overlapping layers of the segmented pieces is maintained at approximately a maximum value. That is, the first non-conforming part connection portion (42) of the current collector (40) can be connected to the first non-conforming part (11) so as to overlap at least approximately 50% with the welding target area.

[0100] The terminal coupling portion (43) may be positioned spaced apart from the first non-reinforced portion coupling portion (42). Preferably, the terminal coupling portion (43) may be located inside the edge portion (41). The terminal coupling portion (43) may be joined to the cell terminal (30) by welding. To secure a welding area for joining with the flat portion formed on the bottom surface of the cell terminal (30), the terminal coupling portion (43) may have a diameter substantially equal to or larger than the diameter of the flat portion formed on the bottom surface of the cell terminal (30).

[0101] Meanwhile, the first non-removable part coupling portion (42) and the terminal coupling portion (43) may be electrically connected by the rim portion (41). For example, the first non-removable part coupling portion (42) and the terminal coupling portion (43) may be indirectly connected by the rim portion (41). Accordingly, the first non-removable part (11) may be electrically connected to the cell terminal (30) through the current collector (40).

[0102]

[0103] The bridge portion (44) may be configured to connect the rim portion (41) and the terminal coupling portion (43). Preferably, the bridge portion (44) may be configured such that the current collector (40) extends inward from the rim portion (41) and is connected to the terminal coupling portion (43). The bridge portion (44) may be positioned between the first non-removable portion coupling portion (42).

[0104] Preferably, the bridge portion (44) may be provided in multiple numbers. For example, each of the multiple bridge portions (44) may be positioned between adjacent first non-removable portion connecting portions (42). Referring to FIG. 6, the bridge portions (44) may be positioned at intervals of approximately 180 degrees with respect to the center of the current collector (40). In this case, the bridge portions (44) may be composed of two along the circumferential direction. In such an embodiment, the bridge portions (44) may be configured to face each other.

[0105] The bridge portion (44) may be configured to have a roughly rod shape extending from the terminal coupling portion (43) to the rim portion (41). That is, the bridge portion (44) may be located on an imaginary straight line passing through the center of the current collector (40).

[0106]

[0107] Meanwhile, the edge portion (41), the first non-removable portion coupling portion (42), the terminal coupling portion (43), and the bridge portion (44) of the current collector (40) according to one embodiment of the present invention may be separated by a slit (S). The slit (S) refers to an area that penetrates the current collector (40). The slit (S) may have the shape of a straight line and / or a curve extending in one direction.

[0108] For example, referring to FIG. 6, a slit (S) is formed inside a current collector (40) having a roughly circular shape, thereby forming a rim portion (41), a first non-removable portion connecting portion (42), a terminal connecting portion (43), and a bridge portion (44). At this time, the shape, such as the length and / or width of the slit (S), can be varied by taking into account the internal resistance level of the battery, the opening ratio, and the welding strength.

[0109] In the embodiment of FIG. 6, the slit (S) may be formed along the inner end of the rim portion (41). Accordingly, the slit (S) may be configured in a roughly circular shape. The slit (S) shall be referred to as the first slit (S1). At this time, the first slit (S1) may be configured as at least one arc. Preferably, the first slit (S1) may be configured as a plurality of arcs. By the first slit (S1), the rim portion (41) may be separated from the current collector (40).

[0110] Meanwhile, in the embodiment of FIG. 6, the slit (S) can function as a structure that separates the first non-removable part coupling portion (42) from the terminal coupling portion (43) and the bridge portion (44). Such a slit (S) is referred to as the second slit (S2). That is, the second slit (S2) can be formed between the first non-removable part coupling portion (42) and the terminal coupling portion (43) and the bridge portion (44). For example, referring to FIG. 6, the second slit (S2) can be formed along the edge of an imaginary band passing through the center of the current collector (40) with a predetermined width. At this time, the second slit (S2) can be composed of multiple straight lines and / or curves. Referring to FIG. 6, the second slit (S2) can be extended in a direction approximately parallel to the imaginary straight line passing through the center of the current collector (40). The second slit (S2) may be provided in multiple numbers, and the multiple second slits (S2) may extend in directions parallel to each other. The second slit (S2) may be configured to cross the central region of the current collector (40).

[0111] More specifically, the outer region of the first slit (S1) becomes the edge portion (41). The inner region of the first slit (S1) becomes the first bare-bones connecting portion (42), the terminal connecting portion (43), and the bridge portion (44). Based on FIG. 7, the terminal connecting portion (43) and the bridge portion (44) are located in the region between the plurality of second slits (S2). The first bare-bones connecting portion (42) is located in the region between the first slit (S1) and the second slit (S2).

[0112]

[0113] FIG. 7 is a drawing for explaining a current collector (40) according to another embodiment of the present invention.

[0114] Referring to FIG. 7, the current collector (40) may be configured to have a form in which the first slit (S1) and the second slit (S2) are connected to each other. That is, one end of the first slit (S1) and one end of the second slit (S2) may be connected to each other. At this time, the point where the first slit (S1) and the second slit (S2) are connected may be configured in a curved shape. Alternatively, as another embodiment, the point where the first slit (S1) and the second slit (S2) are connected may be configured in a pointed shape.

[0115] According to a structure such as that of the embodiment of FIG. 7, the first slit (S1) and the second slit (S2) are connected to form a single slit (S), thereby improving the ease of forming the slit (S) when manufacturing the current collector (40). In addition, according to the above structure, the area of ​​the slit (S) is increased, and the degree of freedom for each location can be increased.

[0116] Here, each location may refer to a plurality of parts partitioned by slits (S) in the entire house (40). And, the degree of freedom for each location may refer to the constraint between each location. For example, a high degree of freedom for each location may mean that the constraint between locations is low.

[0117] Specifically, for example, if each area of ​​the current collector (40) is provided as a single unit without being divided into individual parts by a slit (S), or if the area of ​​the slit (S) is excessively small and formed narrowly, when welding heat is applied or pressure is applied to any part of the current collector (40), the heat or pressure may have a significant effect on the remaining parts, and as a result, problems such as thermal deformation, bending, or kinking of the current collector (40) may occur.

[0118] However, when the area of ​​the slit (S) is increased, as in the current collector (40) according to the present invention, the effect of heat input or pressure at one location on other locations can be significantly reduced, and the degree of freedom at each location is increased, so that problems such as thermal deformation, bending, or kinking of the current collector (40) can be significantly reduced.

[0119] In addition, as shown in the above configuration, when the first slit (S1) and the second slit (S2) are connected, there is also an advantage that the movement of the bridge part (44) and the terminal coupling part (43) in the winding axis direction can be made easier.

[0120]

[0121] FIG. 8 is a drawing for explaining a current collector (40) according to another embodiment of the present invention.

[0122] Referring to FIG. 8, in one aspect of the present invention, the bridge portion (44) may be configured so that its length can be extended.

[0123] For example, the bridge portion (44) may have at least one bend portion (44a). Referring to FIG. 8, the bridge portion (44) may have at least one bend portion (44a). Preferably, the bend portion (44a) of the bridge portion (44) may have a structure that is folded multiple times. For example, the bend portion (44a) may be configured such that at least a portion of the bridge portion (44) is folded in a wrinkled shape. The bend portion (44a) may be configured to have a fan shape that is folded multiple times. The bend line where the bridge portion (44) is folded may extend in a direction approximately perpendicular to the direction in which the bridge portion (44) is extended.

[0124] In this regard, in the case of a conventional cylindrical battery, a gap may occur between the current collector (40) and the cell terminal (30) due to an axial height deviation of the electrode assembly (10). When the current collector (40) and the cell terminal (30) are welded in such a state where a gap has occurred, the current collector (40) is pressed down, causing stress to occur in the weld. Consequently, there is a concern that the weld may be damaged due to this stress.

[0125] However, according to the configuration in which the bridge portion (44) is elongable as in the present invention, damage to the weld between the current collector (40) and the cell terminal (30) can be effectively prevented. Specifically, according to the above configuration, even if a gap occurs between the current collector (40) and the cell terminal (30) due to an axial height deviation of the electrode assembly (10), the current collector (40) can be elongated in the winding axial direction as the bent portion (44a) of the bridge portion (44) unfolds. Accordingly, the gap between the current collector (40) and the cell terminal (30) can be compensated. Therefore, according to the present invention, by dispersing the stress that could conventionally occur due to the compression of the current collector (40), the stress occurring in the weld between the current collector (40) and the cell terminal (30) can be reduced. In addition, the tensile force caused by the gap can be effectively reduced. In addition, according to this structure, damage to the current collector (40) can be prevented during stretching without the need for a separate structure. That is, the current collector (40), composed of a single plate, can be effectively stretched without damage. Furthermore, according to the present invention, the production cost can be lowered and the production process simplified during the production of the current collector (40).

[0126]

[0127] FIG. 9 is a drawing for explaining the shape in which a current collector (40) according to one embodiment of the present invention is welded to an electrode assembly (10).

[0128] Referring to FIG. 9, the first non-reinforced portion connecting portion (42) of the current collector (40) is welded to the first non-reinforced portion (11). At this time, a weld (W) may be provided between the first non-reinforced portion connecting portion (42) and the first non-reinforced portion (11). In this case, welding may be applied using, for example, laser welding, ultrasonic welding, spot welding, etc.

[0129] Preferably, a plurality of welded portions (W) may be provided between the first non-reinforced portion (11) and the current collector (40). That is, a plurality of welded portions (W) formed between the first non-reinforced portion joining portion (42) and the first non-reinforced portion (11) may be provided.

[0130] In one aspect of the present invention, the weld (W) may be provided continuously along the circumferential direction on the first non-reinforced joint (42). Specifically, the angle between a virtual straight line passing through one circumferential end of the weld (W) and the center of the current collector (40), and the virtual straight line passing through the other circumferential end of the weld (W) and the center of the current collector (40), may be configured to be approximately 120 degrees or more and approximately 160 degrees or less. Preferably, the angle between a virtual straight line passing through one circumferential end of the weld (W) and the center of the current collector (40), and the virtual straight line passing through the other circumferential end of the weld (W) and the center of the current collector (40), may be configured to be approximately 130 degrees or more and approximately 150 degrees or less.

[0131] According to this configuration, the area of ​​the weld (W) between the first non-reinforced portion (42) and the first non-reinforced portion (11) can be increased compared to the conventional current collector (40). Accordingly, the tensile strength increases and the internal resistance of the cell decreases, thereby improving the performance of the battery cell (1). That is, according to the above configuration of the present invention, as the area of ​​the first non-reinforced portion (42) increases compared to the conventional current collector (40), the weldable area can be easily secured. For example, referring to FIG. 5 which illustrates the conventional current collector (40), the area of ​​the first non-reinforced portion (42) is divided by the bridge portion (44) extended in the horizontal direction, and the area of ​​the first non-reinforced portion (42) is also reduced by the area occupied by the bridge portion (44), so the weldable area between the first non-reinforced portion (42) and the first non-reinforced portion (11) is significantly reduced. On the other hand, according to the present invention, since the first non-removable part joining part (42) is configured to be spread about 180 degrees apart from the center of the current collector (40), the welded part (W) area between the first non-removable part joining part (42) and the first non-removable part (11) can be expanded.

[0132]

[0133] Referring to FIG. 9, in one aspect of the present invention, the ratio of the total area of ​​the plurality of welds (W) to the total area of ​​the current collector (40) can be formed to be 0.7 or more and 0.9 or less.

[0134] Here, the total area of ​​the current collector (40) may be the area of ​​the inner edge of the current collector (40) when viewed from the height direction (direction parallel to the Z-axis), and may be the area assumed to be filled in the empty parts in the form of holes, such as the first slit (S1), the second slit (S2), and the current collector hole (H2). Additionally, here, the total area of ​​the plurality of welds (W) may be the sum of the areas occupied by each of the welds (W) when viewed from the height direction (direction parallel to the Z-axis).

[0135] If the ratio of the total area of ​​the plurality of welded parts (W) to the total area of ​​the above-mentioned current collector (40) is less than 0.7, the area of ​​the welded part (W) between the first unsecured part joint (42) and the first unsecured part (11) is not sufficiently secured, so the tensile strength is excessively low and the internal resistance of the cell is excessively high, resulting in a problem where the performance of the battery cell (1) is poor.

[0136] In addition, if the ratio of the total area of ​​the plurality of welded parts (W) to the total area of ​​the current collector (40) exceeds 0.9, there is a problem that although the area of ​​the welded part (W) between the first non-conforming part (42) and the first non-conforming part (11) can be sufficiently secured, it may become excessively difficult to secure the area for the remaining parts of the current collector (40), excluding the first non-conforming part (42), such as the first slit (S1), the second slit (S2), the current collector hole (H2), the edge part (41), the terminal connecting part (43), and the bridge part (44). Furthermore, in this case, there is also a problem that the welding heat generated in one of the first non-conforming parts (42) may be excessively transferred to another first non-conforming part (42).

[0137] Therefore, as in the present invention, if the ratio of the total area of ​​the plurality of welded portions (W) to the total area of ​​the current collector (40) is formed to be 0.7 or more and 0.9 or less, the area of ​​the welded portions (W) is sufficiently secured so that the performance of the battery cell (1) can be improved, while the remaining part of the current collector (40) excluding the first non-welded portion (42) is also easily secured, and the welding heat generated at any one of the first non-welded portion (42) can be prevented from being transferred to other parts, thus having a significant effect.

[0138] In this regard, the total area of ​​the current collector (40) according to the present invention may be, for example, 490 mm², and the total sum of the areas of each weld (W) formed in two first non-welded joints (42) may be 343 mm² or more and 441 mm² or less, and the ratio of the total area of ​​the plurality of welds (W) to the total area of ​​the current collector (40) may be 0.7 or more and 0.9 or less.

[0139] In addition, to introduce some specific examples, the total area of ​​the current collector (40) according to the present invention may be, for example, 490 mm², and the total sum of the areas of each weld (W) formed in the two first non-reinforced joint parts (42) may be 400 mm². In this case, in the present invention, the ratio of the total area of ​​the plurality of welds (W) to the total area of ​​the current collector (40) may be approximately 0.816.

[0140] Meanwhile, referring to FIG. 5, we examine the case of a conventional current collector (40). In the conventional current collector (40), as with the examples of the present invention described above, the total area of ​​the current collector (40) may be, for example, 490 mm². However, in the conventional current collector (40), due to the area occupied by the bridge portion (44), the total sum of the areas of each weld (W) formed in the four first non-reinforced joint portions (42) is, for example, 332 mm². In this case, the ratio of the total area of ​​the plurality of welds (W) to the total area of ​​the current collector (40) may be formed as approximately 0.678. This figure is approximately 0.138 lower than the figure in the specific example of the present invention corresponding to 0.816, and is a figure corresponding to less than 0.7.

[0141] The conventional current collector (40) has the disadvantage that the ratio of the total area of ​​the multiple welds (W) to the total area of ​​the current collector (40) is, for example, less than 0.7, and as the area of ​​the welds (W) is not sufficiently secured, the tensile strength is excessively low and the internal resistance of the cell is excessively high, resulting in poor performance of the battery cell (1).

[0142]

[0143]

[0144] FIG. 10 is a drawing for illustrating a battery pack including a battery cell (1) according to one embodiment of the present invention.

[0145] Referring to FIG. 10, a battery pack (3) according to one embodiment of the present invention comprises a battery assembly in which a plurality of battery cells (1) according to one embodiment of the present invention as described above are electrically connected, and a pack housing (2) that accommodates the same. In the drawings of the present invention, components such as a busbar for electrical connection, a cooling unit, and a power terminal are omitted for convenience of drawing. In addition, the battery pack (3) may further include various components, such as a BMS, a pack case, a relay, a current sensor, etc., which are components of a battery pack (3) known at the time of filing the present invention.

[0146]

[0147] FIG. 11 is a drawing for explaining a vehicle including the battery pack (3) of FIG. 10.

[0148] Referring to FIG. 11, a vehicle (5) according to one embodiment of the present invention may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle, and includes a battery pack (3) according to one embodiment of the present invention. The vehicle (5) includes four-wheeled vehicles and two-wheeled vehicles. The vehicle (5) operates by receiving power from the battery pack (3) according to one embodiment of the present invention. In addition, the vehicle (5) according to the present invention may further include various other components included in the vehicle in addition to the battery cell (1) or battery pack (3). For example, the vehicle (5) according to the present invention may further include, in addition to the battery cell (1) according to the present invention, a vehicle body, a motor, a control device such as an ECU (electronic control unit), etc.

[0149]

[0150] Meanwhile, although terms indicating direction such as up and down have been used in this specification, these terms are used merely for convenience of explanation, and it is obvious to a person skilled in the art that they may vary depending on the location of the object or the position of the observer.

[0151] Although the present invention has been described above by 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.

[0152]

[0153] [Explanation of the symbol]

[0154] 5: Cars

[0155] 3: Battery Pack

[0156] 2: Pack Housing

[0157] 1: Battery cell

[0158]

[0159] 10: Electrode assembly

[0160] 11: 1st Department of Indefinite Use

[0161] 11a: segment

[0162] 12: 2nd Department of Indefinite Use

[0163] C: Center of the coil

[0164]

[0165] 20: Battery housing

[0166] 20a: External surface

[0167]

[0168] 30: Cell terminal

[0169] G2: Insulating gasket

[0170]

[0171] 40: Whole house

[0172] 41: Border part

[0173] 42: First thumb joint

[0174] 43: Terminal connection part

[0175] 44: Bridge section

[0176] 44a: Bent section

[0177] S: Slit

[0178] S1: 1st slit

[0179] S2: 2nd slit

[0180] H2: Entire house hall

[0181] W: Welded part

Claims

1. An electrode assembly in which a first electrode and a second electrode and a separator interposed between them are wound around a winding axis to define a core and an outer surface, wherein the first electrode includes a first uncoated portion exposed to the outside of the separator and in which an active material layer is not coated at the long end along the winding direction, and at least a portion of the first uncoated portion is used as an electrode tab itself; A battery housing configured to include an opening on one side and to accommodate the electrode assembly through the opening; A cell terminal configured to pass through a surface located on the opposite side of the opening of the battery housing; and A current collector comprising: a rim portion disposed on one side of the electrode assembly; a first non-bonded portion coupling portion extending inwardly from the rim portion and welded to the first non-bonded portion, arranged at 180-degree intervals and facing each other; a terminal coupling portion positioned spaced apart from the first non-bonded portion coupling portion and welded to the cell terminal; and a bridge portion connecting the rim portion and the terminal coupling portion and positioned between the first non-bonded portion coupling portions. A battery cell containing 2. In Paragraph 1, The above-mentioned first non-removable part coupling part and the above-mentioned terminal coupling part are, A battery cell characterized by being electrically connected by the above-mentioned rim portion.

3. In Paragraph 1, A battery cell characterized in that the rim portion, the first non-reinforced portion coupling portion, the terminal coupling portion, and the bridge portion of the above-mentioned current collector are separated by a slit.

4. In Paragraph 3, The above slit is, A first slit formed along the inner end of the above-mentioned edge portion; and A second slit separating the first non-reinforcing portion from the terminal coupling portion and the bridge portion. A battery cell characterized by including 5. In Paragraph 4, A battery cell characterized in that the first slit is composed of at least one arc.

6. In Paragraph 4, A battery cell characterized in that the second slit extends in a direction parallel to a virtual straight line passing through the center of the current collector.

7. In Paragraph 4, A battery cell characterized in that the second slits are provided in plurality, and the plurality of second slits extend in directions parallel to each other.

8. In Paragraph 4, A battery cell characterized in that the second slit is configured to cross the central region of the current collector.

9. In Paragraph 4, A battery cell characterized in that one end of the first slit and one end of the second slit are connected to each other and formed integrally.

10. In Paragraph 1, A battery cell characterized in that the above-mentioned bridge portion is configured to be elongable in length.

11. In Paragraph 1, A plurality of welds are provided between the first non-removable part and the current collector, and A battery cell characterized by being configured such that the angle between a virtual straight line passing through one circumferential end of the weld and the center of the current collector, and a virtual straight line passing through the other circumferential end of the weld and the center of the current collector, is 120 degrees or more and 160 degrees or less.

12. In Paragraph 11, The ratio of the total area of ​​the plurality of welded parts to the total area of ​​the above-mentioned house is, A battery cell characterized by being formed to be 0.7 or higher and 0.9 or lower.

13. A battery cell according to any one of claims 1 to 12; and A pack housing that accommodates a plurality of the above-mentioned battery cells; A battery pack including 14. An automobile comprising a battery pack according to Article 13.

15. A current collector applied to a battery cell comprising: an electrode assembly having a first non-removable portion and a second non-removable portion; a battery housing that accommodates the electrode assembly through an opening formed on one side and is electrically connected to the second non-removable portion; and a cell terminal electrically connected to the first non-removable portion; A rim portion disposed on one side of the above electrode assembly; A first non-reinforced portion connecting part that extends inwardly from the above-mentioned rim portion and is welded to the first non-reinforced portion, and is arranged at 180-degree intervals to face each other; A terminal coupling portion positioned spaced apart from the first non-reinforced portion coupling portion and welded to the cell terminal; and A bridge portion connecting the above-mentioned edge portion and the above-mentioned terminal coupling portion, and located between the above-mentioned first non-reinforced portion coupling portion The entire house including

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