Battery cell, battery pack and automobile including the same

Abstract

A battery cell according to one embodiment of the present invention is an electrode assembly in which a first electrode, a second electrode, and a separator sandwiched therebetween are wound around a winding shaft to define a core and an outer peripheral surface, and the first electrode includes an electrode assembly including a first uncoated portion that is not coated with an active material layer along the winding direction; a battery housing having an opening on one side and accommodating the electrode assembly through the opening; a support disposed on an upper portion of the electrode assembly; and a current collector including a tab connecting portion extending from the support and connected to the first uncoated portion, and a housing connecting portion extending from the support and electrically connected to an inner surface of the battery housing, the length of which is extensible.

Description

[Technical Field]

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

[0002] This application claims priority based on Korean Patent Application No. 10-2022-0150570 filed on November 11, 2022 and Korean Patent Application No. 10-2023-0069484 filed on May 30, 2023, and the contents disclosed in the specifications and drawings of said applications are incorporated herein in their entirety. [Background technology]

[0003] Secondary batteries, which are easily applicable to various products and have electrical properties such as high energy density, are widely used not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs) that are driven by electrical sources. These secondary batteries not only have the temporary advantage of dramatically reducing the use of fossil fuels, but also have the advantage of not producing any by-products associated with energy use, and are therefore attracting attention as a new energy source that is environmentally friendly and improves energy efficiency.

[0004] Currently widely used types of secondary batteries include lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel metal hydride batteries, and nickel zinc batteries. The operating voltage of such a unit secondary battery cell, i.e., a unit battery cell, is approximately 2.5V to 4.5V. Therefore, if a higher output voltage is required, a battery pack may be configured by connecting multiple battery cells in series. Furthermore, depending on the charge / discharge capacity required for the battery pack, a battery pack may also be configured by connecting multiple battery cells in parallel. Therefore, the number of battery cells included in the battery pack may be variously set depending on the required output voltage and / or charge / discharge capacity.

[0005] On the other hand, in a current collector configured to electrically connect the electrode assembly and the battery housing, there is a difference in height between the part that is placed on the electrode assembly and the part that is placed on the beading part of the battery housing, so the connection part that connects them must be configured or extended to have a length greater than the connection distance in a plane.

[0006] For this reason, in the past, a bellows-like structure was used for the connection part, but in this case, it was difficult to manufacture a current collector by simply processing the plate material within the range where the flat shape of the plate material was maintained, and a process of applying a separate molding to the processed plate material to deform the shape into a three-dimensional shape was required. Meanwhile, if such a structure that allows the connection part to be stretched is not used for the current collector, there was a problem that the connection part would be damaged during the stretching process.

[0007] Therefore, in order to solve these problems, a current collector with a new structure is currently desired. Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a current collector that can be stretched without wrinkles or breakage even without a separate structure.

[0009] According to another aspect of the present invention, another object of the present invention is to make it possible to manufacture a current collector by simply processing a plate material within a range in which the shape of the flat plate material is maintained.

[0010] However, the technical problems that the present invention aims to solve are not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below. [Means for solving the problem]

[0011] According to one embodiment of the present invention, a battery cell includes an electrode assembly in which a first electrode, a second electrode, and a separator sandwiched therebetween are wound around a winding shaft to define an outer circumferential surface of a core, the first electrode including a first uncoated portion that is not coated with an active material layer along the winding direction; a battery housing having an opening on one side and accommodating the electrode assembly through the opening; a support disposed on an upper portion of the electrode assembly; and a current collector including a tab connecting portion extending from the support and connected to the first uncoated portion, and a housing connecting portion extending from the support and electrically connected to an inner surface of the battery housing, the length of which is extensible.

[0012] In one aspect of the present invention, the boundary region between the support portion and the housing joint portion may be bent so that an end of the housing joint portion faces the opening and the inner surface of the battery housing.

[0013] In another aspect of the present invention, the housing joint portion may extend in the winding axial direction and in the radial direction of the electrode assembly.

[0014] In one aspect of the present invention, the housing coupling portion may include a contact portion coupled to an inner surface of the battery housing, and a connecting portion connecting the support portion and the contact portion.

[0015] In another aspect of the present invention, the housing coupling portion may be configured so that its length is reducible.

[0016] In yet another aspect of the present invention, at least a portion of the housing coupling portion may be configured to have a rim shape with a hollow center.

[0017] For example, at least a portion of the housing joint portion may have an elliptical planar shape.

[0018] In another embodiment of the present invention, at least a portion of the housing joint portion may have a polygonal shape in plan view.

[0019] In still another aspect of the present invention, at least one groove indented toward the inside of the connection portion may be provided on the outer circumferential edge of the connection portion.

[0020] In yet another aspect of the present invention, the connection portion may include at least one bent portion.

[0021] Preferably, the bent portion may have a shape that is convex in a direction facing the open portion.

[0022] In yet another aspect of the present invention, the contact portion may be configured to have a continuous shape along the inner surface of the battery housing.

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

[0024] The present invention also provides a motor vehicle, the motor vehicle including at least one battery pack according to the above-described embodiment. [Effects of the Invention]

[0025] According to the present invention, the current collector can be smoothly stretched.

[0026] More specifically, according to the present invention, no wrinkles or breakage occurs when the current collector is stretched without any additional structure.

[0027] In another aspect, according to the present invention, a current collector can be produced by simply processing a plate material within a range in which the shape of the flat plate material is maintained.

[0028] However, the effects obtained through the present invention are not limited to the above-mentioned effects, and other technical effects not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.

[0029] The drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further understand the technical concepts of the present invention as well as the content of the invention, and therefore the present invention should not be interpreted as being limited to only the matters depicted in the drawings. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a diagram illustrating a battery cell according to an embodiment of the present invention; [Figure 2] FIG. 2 is a vertical cross-sectional perspective view of FIG. [Figure 3] FIG. 2 is a vertical cross-sectional view of the battery cell in FIG. [Figure 4] FIG. 2 is a diagram illustrating a current collector according to an embodiment of the present invention. [Figure 5] FIG. 5 is a diagram illustrating a state in which the current collector in FIG. 4 is stretched. [Figure 6] FIG. 5 is a cross-sectional view of the current collector taken along line A shown in FIG. [Figure 7] 4A and 4B are views illustrating a housing coupling portion of a current collector according to an embodiment of the present invention; [Figure 8] 8 is a view for explaining a process in which the housing coupling portion in FIG. 7 is extended. [Figure 9] FIG. 10 is a diagram illustrating a current collector according to another embodiment of the present invention. [Figure 10] FIG. 10 is a diagram illustrating a current collector according to still another embodiment of the present invention. [Figure 11] FIG. 10 is a diagram illustrating a current collector according to still another embodiment of the present invention. [Figure 12] FIG. 10 is a diagram illustrating a current collector according to still another embodiment of the present invention. [Figure 13]FIG. 13 is a diagram illustrating a state in which the current collector in FIG. 12 is stretched. [Figure 14] 1 is a diagram illustrating a battery pack including a battery cell according to an embodiment of the present invention; [Figure 15] FIG. 15 is a diagram for explaining an automobile including the battery pack in FIG. 14. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms and words used in this specification and claims should not be construed as being limited to their ordinary or dictionary meanings, but should be construed as meanings and concepts corresponding to the technical ideas of the present invention, in accordance with the principle that the inventor can appropriately define the concepts of terms himself / herself in order to best describe the invention. Therefore, it should be understood that the embodiment described in this specification and the configuration shown in the drawings are merely a preferred embodiment of the present invention and do not represent the entire technical ideas of the present invention, and therefore, various equivalent and modified embodiments may be available as of the time of filing this application.

[0032] In addition, in order to facilitate understanding of the invention, the accompanying drawings may not be drawn to scale, and the dimensions of some components may be exaggerated. In addition, the same reference numerals may be used for the same components in different embodiments.

[0033] A statement that two comparison objects are identical means that they are "substantially identical." Therefore, being substantially identical may include cases where there is a deviation that is recognized as a low level in the art, for example, a deviation of 5% or less. Furthermore, the uniformity of a certain parameter in a given region may mean that it is uniform from an average perspective.

[0034] Although phrases such as "first" and "second" can be used to describe various components, it goes without saying that these components are not limited by these phrases in any way. These phrases are used merely to distinguish one component from another, and unless otherwise specified, it goes without saying that a first component may also be a second component.

[0035] Throughout the specification, unless otherwise indicated herein or clearly contradicted by context, each element is to be construed as covering both the singular and the plural.

[0036] The phrase "above (or below)" a component or "above (or below)" a component means that the component is placed in contact with the upper surface (or lower surface) of the component, and may also mean that there may be other components interposed between the component and the component placed above (or below) the component.

[0037] Furthermore, when a component is described as being "coupled," "coupled," or "connected" to another component, it should be understood that the components may be directly coupled or connected to each other, or that other components may be "intervening" between the components, or that the components may be "coupled," "coupled," or "connected" via other components.

[0038] Throughout the specification, when "A and / or B" is used, this means A, B or A and B, unless otherwise specified in the specification or clearly contradicted by the context, and when "C to D" is used, this means C or more and D or less, unless otherwise specified.

[0039] For ease of explanation, in this specification, the direction along the longitudinal direction of the winding shaft of the electrode assembly 10 wound in a jelly roll shape will be referred to as the axial direction Y. The direction surrounding the winding shaft will be referred to as the circumferential direction or the peripheral direction X. The direction toward the winding shaft or the direction away from the winding shaft will be referred to as the radial direction. Of these, the direction toward the winding shaft will be particularly referred to as the centripetal direction, and the direction away from the winding shaft will be particularly referred to as the centrifugal direction.

[0040] Fig. 1 is a diagram for explaining a battery cell 1 according to one embodiment of the present invention, and Fig. 2 is a vertical cross-sectional perspective view of Fig. 1. Fig. 3 is a vertical cross-sectional view of the battery cell 1 in Fig. 1.

[0041] 1, a battery cell 1 according to an embodiment of the present invention includes an electrode assembly 10, a battery housing 20, and a current collector 30. The battery cell 1 may further include a housing cover 40. The present invention is not limited by the shape of the battery, and may also be applied to batteries of other shapes, such as prismatic batteries.

[0042] The electrode assembly 10 includes a first uncoated region 11 and a second uncoated region 12. More specifically, the electrode assembly 10 has a structure in which a first electrode, a second electrode, and the separator sandwiched therebetween are wound around a winding shaft to define a core and an outer circumferential surface. That is, the electrode assembly 10 applied to the embodiment of the present invention may be a jelly roll-type electrode assembly 10. In this case, an additional separator may be provided on the outer circumferential surface of the electrode assembly 10 for insulation from the battery housing 20. The electrode assembly 10 may have any winding structure known in the art, without limitation.

[0043] The first electrode includes a first electrode current collector and a first electrode active material coated on one or both sides of the first electrode current collector. An uncoated portion, where the first electrode active material is not coated, is present at one end of the first electrode in the width direction (the direction parallel to the height direction of the battery cell 1 shown in FIG. 1 ). That is, the first electrode includes a uncoated portion at the end of the long side along the winding direction that is not coated with an active material and is exposed to the outside of the separator. Hereinafter, the uncoated portion functioning as the first electrode tab will be referred to as the first uncoated portion 11. The first uncoated portion 11 is provided at the upper portion of the electrode assembly 10 housed in the battery housing 20 in the height direction (the direction parallel to the height direction of the battery cell 1 shown in FIG. 1 ). That is, the first electrode includes a first uncoated portion 11 at the end of the long side that is not coated with an active material layer and is exposed to the outside of the separator, and at least a portion of the first uncoated portion 11 itself is used as an electrode tab. The first uncoated portion 11 may be, for example, a negative electrode tab.

[0044] Meanwhile, at least a portion of the first uncoated portion 11 may include a plurality of segments separated 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.

[0045] 2 and 3, the plurality of segments of the bent first plain portion 11 may overlap in multiple layers to form a folded surface. In this case, a tab connection portion 32 of a current collector 30, which will be described later, may be bonded to the folded surface. The tab connection portion 32 may be bonded to a region where the plurality of segments overlap in multiple layers. In this case, welding may be performed on a certain region while the tab connection portion 32 is placed on the folded surface of the first plain portion 11. That is, the tab connection portion 32 may be bonded to a region where the plurality of segments of the first plain portion 11 overlap in multiple layers. For example, as is clear from FIG. 5, the tab connection portion 32 may have at least one welded portion welded to a certain region while placed on the folded surface of the first plain portion 11.

[0046] The second electrode includes a second electrode current collector and a second electrode active material coated on one or both sides of the second electrode current collector. The other end of the second electrode in the width direction (the direction parallel to the height direction of the battery cell 1 shown in FIG. 1 ) has an uncoated portion where the second electrode active material is not coated. That is, the second electrode includes a uncoated portion at the end of the long side along the winding direction that is not coated with an active material and is exposed to the outside of the separator. Hereinafter, the uncoated portion functioning as the second electrode tab will be referred to as the second uncoated portion 12. The second uncoated portion 12 is provided at the lower part of the height direction of the electrode assembly 10 housed in the battery housing 20. That is, the second electrode includes a second uncoated portion 12 at the end of the long side that is not coated with an active material layer and is exposed to the outside of the separator, and at least a portion of the second uncoated portion 12 itself can be used as an electrode tab. The second uncoated portion 12 may be, for example, a positive electrode tab.

[0047] Meanwhile, in the embodiment of the present invention, the positive electrode active material coated on the positive electrode plate and the negative electrode active material coated on the negative electrode plate may be any active material known in the art without any limitation.

[0048] Referring to FIG. 1, the battery housing 20 is a generally cylindrical container having an opening on one side and is made of a conductive metal material. The side surface of the battery housing 20 and the bottom surface opposite the opening are generally formed as a single unit. That is, the battery housing 20 generally has an open upper end in its height direction and a closed lower end. The bottom surface of the battery housing 20 may have a generally flat shape. The battery housing 20 accommodates the electrode assembly 10 through an opening formed on one side in its height direction. The battery housing 20 may also accommodate an electrolyte through the opening.

[0049] The battery housing 20 may include a beading portion 21 formed at an end adjacent to an opening provided at the top end of the battery housing 20. The battery housing 20 may further include a crimping portion 22 formed on the beading portion 21. The beading portion 21 has a shape in which the periphery of the battery housing 20 is pressed to a predetermined depth. More specifically, the beading portion 21 may have a shape in which the periphery of the battery housing 20 is pressed inward in a region between an opening formed on one side of the battery housing 20 and a receiving portion that receives the electrode assembly 10.

[0050] The beading portion 21 is formed on the upper portion of the electrode assembly 10. The inner diameter of the battery housing 20 in the area where the beading portion 21 is formed is formed to be smaller than the diameter of the electrode assembly 10. At least one tab coupling portion 32 of the current collector 30, which will be described later, may be located further below the beading portion 21.

[0051] The beading portion 21 provides a support surface on which the housing cover 40 can be placed. The beading portion 21 may also provide a support surface on which at least a portion of the peripheral edge of the current collector 30 (described later) can be placed and coupled. That is, at least a portion of the peripheral edge of the current collector 30 and / or the peripheral edge of the housing cover 40 according to an embodiment of the present invention may be placed on the upper surface of the beading portion 21. To stably support at least a portion of the peripheral edge of the current collector 30 and / or the peripheral edge of the housing cover 40, the upper surface of the beading portion 21 may have a shape extending in a direction generally aligned with the lower surface of the battery housing 20, i.e., in a direction generally perpendicular to the sidewall of the battery housing 20.

[0052] The beading portion 21 prevents the electrode assembly 10, which has a size roughly corresponding to the inner diameter of the battery housing 20, from protruding through an opening formed at the upper end of the battery housing 20, and can function as a support portion on which the housing cover 40 is placed. The beading portion 21 can function as a support portion for fixing not only the housing cover 40 but also the contact portion 33a of the current collector 30, the seal gasket G1, etc.

[0053] The crimping portion 22 is formed on the upper portion of the beading portion 21. The crimping portion 22 has an extended and bent shape so as to enclose the peripheral portion of the housing cover 40 disposed on the upper portion of the beading portion 21. Due to the shape of the crimping portion 22, the housing cover 40 is fixed onto the beading portion 21.

[0054] 1 and 2, a current collector 30 according to an embodiment of the present invention is housed inside a battery housing 20 and is electrically connected to the electrode assembly 10 and the battery housing 20. That is, the current collector 30 electrically connects the electrode assembly 10 and the battery housing 20.

[0055] FIG. 4 is a diagram illustrating a current collector 30 according to one embodiment of the present invention.

[0056] Referring to FIG. 4, the current collector 30 includes a support portion 31 located on one side of the electrode assembly 10, a tab connecting portion 32 extending from the support portion 31 and connecting to the first plain portion 11, and a housing connecting portion 33 extending from the support portion 31 and connecting to the inner surface of the battery housing 20.

[0057] The tab coupling portion 32 and the housing coupling portion 33 are indirectly connected via the support portion 31 and are not directly connected to each other. Therefore, when an external impact is applied to the battery cell 1 according to an embodiment of the present invention, the possibility of damage to the coupling portion between the current collector 30 and the electrode assembly 10 and the coupling portion between the current collector 30 and the battery housing 20 can be minimized.

[0058] 4, there may be at least one or more tab coupling portions 32 and / or housing coupling portions 33. The at least one tab coupling portion 32 and the at least one housing coupling portion 33 may be arranged, for example, in a substantially radial pattern, a cross pattern, or a combination thereof, with respect to the center of the current collector 30. In another embodiment, each of the multiple housing coupling portions 33 may be arranged between adjacent tab coupling portions 32.

[0059] 3 , the support portion 31 and the plurality of tab connecting portions 32 are disposed on the upper portion of the electrode assembly 10. The tab connecting portions 32 are connected to the first uncoated portion 11 of the electrode assembly 10. The tab connecting portions 32 may be connected to the first uncoated portion 11 by welding along the radial direction of the electrode assembly 10, for example. The tab connecting portions 32 may be connected to the first uncoated portion 11 by welding in a state generally parallel to the lower surface of the battery housing 20, for example. The welds formed between the first uncoated portion 11 and the tab connecting portions 32 may form, for example, a generally linear weld pattern extending along the radial direction of the electrode assembly 10.

[0060] Meanwhile, not only the tab coupling portion 32 but also the support portion 31 may be coupled to the first uncoated portion 11. The tab coupling portion 32 and the first uncoated portion 11 may be coupled by welding. When a beading portion 21 is formed on the battery housing 20, the support portion 31 and the tab coupling portion 32 are located below the beading portion 21.

[0061] The support portion 31 may have a current collector hole H2 formed at a position corresponding to a winding hole H1 formed in approximately the center of the electrode assembly 10. The winding hole H1 and the current collector hole H2, which are connected to each other, may function as a passage for inserting a welding rod or for irradiating a laser beam to weld the terminal 50 to the second current collector 30 or to weld the terminal to a lead tab (not shown). The current collector hole H2 may have a diameter substantially the same as or larger than the diameter of the winding hole H1 of the electrode assembly 10 so as not to obstruct the winding hole H1 formed in the core of the electrode assembly 10. If the diameter of the current collector hole H2 is excessively smaller than the diameter of the winding hole H1, the hole formed in the winding hole H1 may be obstructed, reducing the injection performance. Furthermore, it may be difficult to secure sufficient space for inserting a welding device or for irradiating a laser.

[0062] The plurality of tab bonding portions 32 may have a shape that extends generally radially from the support portion 31 of the current collector 30 toward the side wall of the battery housing 20. Each of the plurality of tab bonding portions 32 may be located apart from one another along the circumference of the support portion 31.

[0063] The multiple housing joints 33 may have a shape that extends substantially radially from the support portion 31 of the current collector 30 toward the side wall of the battery housing 20. Each of the multiple housing joints 33 may be located apart from one another along the circumference of the support portion 31. At least one housing joint 33 may be located between adjacent tab joints 32.

[0064] The housing coupling portion 33 may extend from the support portion 31 and be electrically coupled to the inner surface of the battery housing 20. For example, the housing coupling portion 33 may be coupled to the inner surface of the battery housing 20, such as the beading portion 21. In particular, the housing coupling portion 33 may be coupled to the upper surface of the beading portion 21.

[0065] In one aspect of the present invention, the housing coupling portion 33 may be configured so that its length is extendable, as will be described in detail below with reference to FIGS.

[0066] FIG. 4 is a diagram illustrating a current collector 30 according to one embodiment of the present invention, and FIG. 5 is a diagram illustrating a state in which the current collector 30 in FIG. 4 has been stretched.

[0067] Referring to FIGS. 4 and 5, the housing connector 33 may be configured to be extendable. That is, the housing connector 33 may be configured so that the length thereof when the housing connector 33 is stretched is greater than the length thereof when the housing connector 33 is not stretched. For example, FIG. 4 shows a current collector 30 before being stretched. The current collector 30 of FIG. 4 may be made from a plate material having a flat shape. That is, when manufacturing the current collector 30, the current collector 30 as shown in FIG. 4 may be manufactured by cutting and processing a flat plate material. The current collector 30 may be stretched as shown in FIG. 5 before being assembled into a battery cell or during assembly.

[0068] That is, according to an embodiment of the present invention, the current collector 30 manufactured from a single flat plate can be easily stretched without any additional structure. More specifically, with this structure, even without any additional structure, wrinkles and breakage do not occur when the current collector 30 is stretched. That is, the current collector 30 manufactured from a single plate can be stretched without wrinkles and breakage. Furthermore, according to an embodiment of the present invention, even if the current collector 30 is manufactured only in the shape of a flat plate without any additional processes, wrinkles and breakage can be prevented when the current collector 30 is stretched. In particular, when a separate bellows is formed on the connection portion 33b of the current collector 30 for stretching the connection portion 33b, the risk of the connection portion 33b becoming brittle along the direction of the bellows can be reduced. In addition, the lack of a bellows or other additional structure in the current collector 30 further facilitates smooth current flow. Furthermore, according to an embodiment of the present invention, the production cost and process of the current collector 30 can be reduced. In particular, according to the embodiment of the present invention, it is possible to omit a separate bellows that has conventionally been provided at the connecting portion 33b for extending the connecting portion 33b.

[0069] In another aspect of the present invention, the boundary area between the support portion 31 and the housing joint portion 33 may be configured so that the end of the housing joint portion 33 is bent so as to face the open portion and the inner surface of the battery housing 20.

[0070] 3 and 5, the housing coupling part 33 is bent toward the top of the battery cell. That is, the current collector 30 may be assembled into the battery cell in a state where a portion of the current collector 30 is bent and deformed from a flat plate state at the time of manufacture. In particular, the boundary region between the support part 31 and the housing coupling part 33 may be bent, and at this time, the end of the housing coupling part 33 may be bent to face the opening.

[0071] Preferably, the housing coupling portion 33 may be configured to extend in the winding axial direction and the radial direction of the electrode assembly 10 .

[0072] 2 and 3, the housing coupling portion 33 may extend in an upwardly inclined direction around the winding axis of the electrode assembly 10. In order for the current collector 30 to extend upward from the flat plate state as shown in FIG. 5, the boundary region between the support portion 31 and the housing coupling portion 33 must be bent upward, and as a result, the current collector 30 can have a predetermined height in the vertical direction. That is, the current collector 30 has a predetermined total height, and the total height can be formed to be variable within a certain range.

[0073] 3 to 5, the housing coupling part 33 may include a contact part 33a coupled to the inner surface of the battery housing 20 and a connection part 33b connecting the support part 31 and the contact part 33a.

[0074] The contact portion 33a is bonded onto the inner surface of the battery housing 20. In the case where a beading portion 21 is formed on the battery housing 20, the contact portion 33a may be bonded onto the beading portion 21. In this case, for stable contact and bonding, both the beading portion 21 and the contact portion 33a may have a shape extending in a direction that is generally aligned with the lower surface of the battery housing 20, i.e., in a direction that is generally perpendicular to the side wall of the battery housing 20.

[0075] Meanwhile, the contact portion 33a may be welded to the upper surface of the beading portion 21. That is, the weld may be formed in the upper surface region of the beading portion 21. The weld formed between the contact portion 33a and the beading portion 21 may be narrower than the upper surface of the beading portion 21. The welding for connecting the battery housing 20 and the current collector 30 may be performed by, for example, laser welding, ultrasonic welding, or spot welding.

[0076] FIG. 6 is a cross-sectional view of the current collector 30 taken along line A shown in FIG.

[0077] Referring to FIG. 6, the housing coupling portion 33 may be configured so that its length is reducible.

[0078] As described above, the current collector 30 is manufactured by cutting and processing a flat plate material. That is, the current collector 30 is initially manufactured as a flat plate material. This state is defined as a first state S1. For example, in the first state S1, the current collector 30 according to one embodiment of the present invention may have a total height (the distance between the upper surface of the contact portion 33a and the upper surface of the support portion 31 along the extension direction of the winding shaft or the distance between the upper surface of the contact portion 33a and the upper surface of the tab coupling portion 32 along the extension direction of the winding shaft) of 0 mm. Meanwhile, as will be described in detail later, the housing coupling portion 33 may have a rim shape with a hollow center. For example, the housing coupling portion 33 may have an oval shape having a major axis L and a minor axis S. For example, in the first state S1, the oval may have a major axis L of approximately 10 mm and a minor axis S of approximately 6 mm.

[0079] Meanwhile, for the current collector 30 to function as a component, a predetermined region of the current collector 30 must be bent. For example, as described above, in order to electrically connect the electrode assembly 10 and the battery housing 20, if there is a height difference between the joining surface of the battery housing 20 and the current collector 30 and the joining surface of the electrode assembly 10 and the current collector 30, the current collector 30 must have a shape that can cover this height difference. Specifically, referring to FIGS. 3 and 5 , the boundary region between the support portion 31 and the housing joining portion 33 of the current collector 30 must be bent upward. The state of the current collector 30 before being bent and deformed and assembled into a battery cell is defined as a second state S2. The current collector 30 in the second state S2 can finally be accommodated inside the battery housing 20 to be assembled into a battery cell. In this case, the total height of the current collector 30 may be configured to be greater than or equal to the axial distance (the distance along the extension direction of the winding axis of the electrode assembly 10) between the upper surface of the electrode assembly 10 and the upper surface of the beading portion 21. If the total height of the current collector 30 were shorter than the axial distance between the upper surface of the electrode assembly 10 and the upper surface of the beading portion 21, the contact portion 33a of the current collector 30 would get caught on the beading portion 21, preventing the support portion 31 and / or the tab coupling portion 32 from contacting the electrode assembly 10. Alternatively, if the current collector 30 is first coupled to the electrode assembly 10 and then housed in the battery housing 20, the contact portion 33a would get caught on the beading portion 21, preventing the electrode assembly 10 from reaching the bottom of the battery housing 20. Ultimately, this could result in empty space and reduced energy efficiency. For example, in the second state S2, the total height of the current collector 30, i.e., the height in the winding axis direction between the support portion 31 and the contact portion 33a, may be set to about 5 mm, and in this case, the structurally required extension length of the connection portion 33b may be about 1.18 mm.

[0080] Meanwhile, as described above, the total height of the current collector 30 is preferably greater than or equal to the axial distance between the upper surface of the electrode assembly 10 and the upper surface of the beading portion 21. With this structure, the contact portion 33a of the current collector 30 is positioned higher than the beading portion 21. Here, the connecting portion 33b may be compressed so that the contact portion 33a contacts the beading portion 21. In this case, welding may be performed with the contact portion 33a in contact with the beading portion 21. This state in which the contact portion 33a contacts the beading portion 21 is defined as a third state S3. For example, in the third state S3, the total height of the current collector 30 may be set to approximately 3.38 mm, and the connecting portion 33b may be reduced to a predetermined length. That is, the connecting portion 33b, which had been extended to a total height of approximately 5 mm, may be compressed again to 3.38 mm.

[0081] That is, according to an embodiment of the present invention, the housing coupling portion 33 may be configured to be extendable and / or retractable in length. Specifically, the length of the housing coupling portion 33 may be extended during the process of transformation from the first state S1 to the second state S2. Then, the length of the housing coupling portion 33 may be reduced during the process of transformation from the second state S2 to the third state S3. In this way, a structure configured so that the length of the housing coupling portion 33 can be extended and reduced allows a single current collector 30 design to be applied to various battery cells having various sizes and specifications.

[0082] Furthermore, according to an embodiment of the present invention, the current collector 30 made from a single flat plate can be easily stretched and / or compressed without a separate structure. Furthermore, due to this structure, even without a separate structure, wrinkles and breakage do not occur when the current collector 30 is stretched and / or compressed. That is, according to an embodiment of the present invention, even if the current collector 30 is manufactured in the shape of a flat plate without any additional processes, wrinkles and breakage can be prevented when the current collector 30 is stretched and / or compressed.

[0083] FIG. 7 is a view illustrating a housing coupling portion 33 of a current collector 30 according to an embodiment of the present invention, and FIG. 8 is a view illustrating a process in which the housing coupling portion 33 in FIG. 7 is stretched.

[0084] According to one aspect of the present invention, at least a portion of the housing coupling portion 33 may be configured to have a rim shape with a hollow center. In particular, the connection portion 33b of the housing coupling portion 33 may be configured to have a rim shape with a hollow center.

[0085] Here, the rim shape includes, but is not necessarily limited to, a circle. For example, the rim shape referred to in this invention may be a polygonal structure such as a triangle or a rectangle, or may have a specific shape with curved edges. In other words, the rim shape referred to in this invention can be said to encompass any shape that has a hollow center and continuous edges.

[0086] For example, in one embodiment of the present invention, at least a portion of the housing coupling portion 33 may be configured to have an oval planar shape as shown in FIGS. 7 and 8. Here, an oval includes a circle. In particular, the planar shape of the connection portion 33b of the housing coupling portion 33 may be an oval shape. Both the connection portion 33b before and after stretching may have an oval shape. For example, as shown in FIG. 7, the connection portion 33b before stretching may be configured to have a substantially oval shape. Meanwhile, as shown in FIG. 8, when the current collector 30 is stretched, the oval shape of the connection portion 33b may be transformed into another oval shape with a longer major axis L and a shorter minor axis S.

[0087] As described above, by having at least a portion of the housing joint 33 have a structure in which the center is open and the edges are continuous, it is possible to prevent wrinkling and / or breakage from occurring during stretching and / or compression, even for the housing joint 33 having a flat plate shape. In other words, according to the embodiment of the present invention, it is possible to improve the durability of the current collector 30 even using a simple manufacturing process.

[0088] FIG. 9 is a diagram illustrating a current collector 30 according to another embodiment of the present invention.

[0089] The current collector 30 in FIG. 9 is substantially similar to the current collector 30 in the above-described embodiment, and therefore, redundant explanations of configurations that are substantially the same as or similar to those in the above-described embodiment will be omitted, and the following description will focus on the differences from the above-described embodiment.

[0090] In another embodiment of the present invention, at least a part of the housing coupling portion 33 may be configured to have a polygonal shape in plan view. In particular, the connecting portion 33b may be configured to have a polygonal shape in plan view.

[0091] 9, the connecting portion 33b may have a diamond-shaped planar shape. However, the shape of the connecting portion 33b according to the embodiment of the present invention is not limited to this diamond shape, and may include any polygonal shape such as a triangle, a rectangle, or a pentagon. In other words, the connecting portion 33b according to the embodiment of the present invention may include any polygonal shape that is open at the center and has continuous edges.

[0092] FIG. 10 is a diagram illustrating a current collector 30 according to still another embodiment of the present invention.

[0093] The current collector 30 in FIG. 10 is substantially similar to the current collector 30 in the above-described embodiment, and therefore, redundant explanations of configurations that are substantially the same as or similar to those in the above-described embodiment will be omitted, and the following description will focus on the differences from the above-described embodiment.

[0094] In still another embodiment of the present invention, at least one groove N indented toward the inside of the connecting portion 33b may be provided on the outer periphery of the connecting portion 33b.

[0095] 10, the connection portion 33b may be configured to have a substantially oval shape, with a plurality of grooves N formed on the outer periphery of the oval. In order for the oval-shaped connection portion 33b to be extended in the direction of the major axis L, the length of the outer periphery of the connection portion 33b must decrease and the length of the inner periphery must increase. In this regard, the current collector 30 is made of metal to ensure electrical conductivity, but metals generally have high strength, which can make it difficult to deform the shape.

[0096] However, according to the embodiment of the present invention, by providing grooves N on the outer periphery of connecting portion 33b that are indented toward the inside of connecting portion 33b, the areas between the grooves N can approach each other when connecting portion 33b is extended, which makes it possible to easily reduce the length of the outer periphery of connecting portion 33b.

[0097] As described above, according to the embodiment of FIGS. 4 to 10 , the connection portion 33b can be easily stretched when the current collector 30 is assembled to the battery cell 1. That is, the current collector 30 manufactured from a single sheet of material can be stretched without wrinkles or breakage, without the need for a separate structure. Specifically, referring to FIG. 3 , the support portion 31 of the current collector 30 is spaced a predetermined distance from the contact portion 33a of the housing coupling portion 33 of the current collector 30 in the direction of the central axis of the battery cell 1. To achieve this state, the current collector 30, which has a planar shape as shown in FIG. 4 , must be deformed while being stretched in the vertical direction. For example, bending may occur at the boundary between the support portion 31 and the connection portion 33b and at the boundary between the connection portion 33b and the contact portion 33a. In this case, in order to maintain a constant radial length from the center of the current collector 30 to the end of the housing coupling portion 33, the length of the connection portion 33b must be increased. 5, when the housing connecting part 33 is bent, the shape of the connecting part 33b is deformed, and the housing connecting part 33 can be easily stretched along its extension direction, while at the same time minimizing the occurrence of wrinkles and / or breakage during the stretching process.

[0098] FIG. 11 is a diagram illustrating a current collector 30 according to still another embodiment of the present invention.

[0099] In one aspect of the present invention, the connection portion 33b may include at least one bent portion F. Preferably, the bent portion F may have a shape that is convex in a direction facing the open portion.

[0100] Referring to FIG. 11 , the bent portion F may be located above an imaginary plane parallel to the bottom surface of the battery housing 20, passing through the center of an imaginary line connecting one end of the contact portion 33a and one end of the tab coupling portion 32. The at least one bent portion F may be bent at an obtuse angle so that the current collectors 30 do not overlap each other when viewed along the longitudinal axis of the battery housing 20. In another embodiment, the connection portion 33b may include multiple bent portions F. In this case, the boundary between the contact portion 33a and the connection portion 33b may be bent at an obtuse angle. That is, the inclination of the connection portion 33b may decrease stepwise or gradually as the connection portion 33b progresses toward the beading portion 21.

[0101] As described above, according to an embodiment of the present invention, the housing coupling portion 33 has a structure including the bent portion F, which further increases the variability of the total height of the current collector 30. That is, the bent portion F can further increase the vertical expansion and contraction capacity of the current collector 30. In addition, stress applied to the current collector 30 during the subsequent battery sizing process can be effectively dispersed.

[0102] In yet another embodiment of the present invention, the contact portion 33 a may be configured to have a continuous shape along the inner surface of the battery housing 20 .

[0103] To maximize the contact area, the current collector 30 may be configured so that the sum of the circumferential extension lengths of the contact portions 33a of the plurality of housing coupling portions 33 is substantially equal to or shorter than the inner circumference of the battery housing 20. In particular, as shown in FIGS. 4 and 5 , the contact portions 33a may be configured to have a continuous shape along the inner surface of the battery housing 20. That is, the contact portions 33a may have a ring shape extending along the inner surface of the battery housing 20. However, if the contact portions 33a are formed in a ring shape, the shape of the contact portions 33a cannot be maintained when the current collector 30 is molded in the longitudinal direction of the battery cell unless the connection portions 33b are extended in the longitudinal direction. Therefore, by configuring at least a portion of the housing coupling portion 33 to be extensible, as in the present embodiment, the shape of the contact portions 33a can be maintained constant.

[0104] Furthermore, since the contact portion 33a is configured to have a continuous shape along the inner surface of the battery housing 20, the contact area between the current collector 30 and the battery housing 20 can be maximized, thereby increasing the bonding strength between the current collector 30 and the battery housing 20. In addition, the internal resistance of the battery can be reduced.

[0105] Meanwhile, because the contact portion 33a is interposed between the beading portion 21 and the seal gasket G1, the above-described structure allows the distance between the beading portion 21 and the seal gasket G1 to be maintained constant. This ensures a uniform compression rate for the seal gasket G1 as a whole during the crimping process. This reduces the risk of leakage of electrolyte or the like after the crimping process.

[0106] For example, as shown in FIG. 3 , the seal gasket G1 may be placed on the beading portion 21 and the contact portion 33a, and then the crimping portion 22 may compress the contact portion 33a, the beading portion 21, and the seal gasket G1. In this case, if the contact portion 33a does not have a continuous shape along the inner surface of the battery housing 20 but has a structure that extends in both directions from the end of the connection portion 33b and has a predetermined width, the beading portion 21 will be divided into an area that contacts the contact portion 33a and an area that does not contact the contact portion 33a. That is, there will be an area where the contact portion 33a is interposed between the beading portion 21 and the seal gasket G1, and an area where the contact portion 33a is not interposed between the beading portion 21 and the seal gasket G1. Meanwhile, when the crimping portion 22 is formed, the compressive force along the circumferential direction is the same, without any difference, and therefore components located inside the crimping portion 22 will be subjected to a constant force. Therefore, the compression ratio of the seal gasket G1 in the region where the contact portion 33a is interposed between the beading portion 21 and the seal gasket G1 is greater than the compression ratio of the seal gasket G1 in the region where the contact portion 33a is not interposed between the beading portion 21 and the seal gasket G1. As a result, the compression ratio of the seal gasket G1 alternately increases and decreases along the circumferential direction. This may weaken the sealing characteristics of the seal gasket G1 and increase the risk of leakage of electrolyte or the like.

[0107] In contrast, according to the embodiment of the present invention, the contact portion 33a is configured to have a continuous shape along the inner surface of the battery housing 20, resulting in a structure in which the contact portion 33a is always interposed between the beading portion 21 and the seal gasket G1. As a result, the compressibility of the seal gasket G1 can be maintained constant along the circumferential direction. This strengthens the sealing characteristics of the seal gasket G1 and effectively reduces the risk of leakage of electrolyte or the like.

[0108] FIG. 12 is a diagram illustrating a current collector 30 according to still another embodiment of the present invention, and FIG. 13 is a diagram illustrating a state in which the current collector 30 in FIG. 12 has been stretched.

[0109] 12 and 13, in another embodiment of the present invention, the contact portion 33a may have an arc shape with at least a portion extending circumferentially along the beading portion 21 of the battery housing 20. This allows the circumferential extension length of the contact portion 33a to be formed to be longer than the width of the connecting portion 33b. For example, the contact portion 33a may have arc shapes extending in opposite directions along the circumferential direction on the beading portion 21 from the intersection of the connecting portion 33b and the contact portion 33a.

[0110] 1 to 3, the housing cover 40 may include a vent portion 41 formed to prevent an increase in internal pressure due to gas generated inside the battery housing 20. The vent portion 41 may be configured to rupture when the internal pressure of the battery housing 20 increases above a certain level. For example, the vent portion 41 may be formed in a portion of the housing cover 40 and may be a region that is structurally weaker than the surrounding region so that it can be easily ruptured when internal pressure is applied. The vent portion 41 may be, for example, a region that is thinner than the surrounding region. Referring to FIGS. 1 and 2, the vent portion 41 may form a substantially circular closed loop.

[0111] 1 to 3, the housing cover 40 covers the opening formed on one side of the battery housing 20. The housing cover 40 may be fixed by a crimping portion 22 formed on the upper end of the battery housing 20. In this case, to improve fixing strength and sealing performance of the battery housing 20, a seal gasket G1 may be interposed between the battery housing 20 and the housing cover 40 and between the current collector 30 and the housing cover 40. In this case, the contact portion 33a may be interposed between the beading portion 21 of the battery housing 20 and the seal gasket G1. In this manner, the contact portion 33a interposed between the beading portion 21 and the seal gasket G1 may be fixed by bending the crimping portion 22 extending upward from the beading portion 21.

[0112] FIG. 14 is a diagram illustrating a battery pack 3 including a battery cell 1 according to an embodiment of the present invention.

[0113] 14, a battery pack 3 according to one embodiment of the present invention includes a battery assembly in which a plurality of battery cells 1 according to one embodiment of the present invention are electrically connected, as described above, and a pack housing 2 that accommodates the battery assembly. For ease of illustration, components such as bus bars for electrical connections, a cooling unit, and power terminals are omitted from the drawings of the present application.

[0114] FIG. 15 is a diagram for explaining an automobile 5 including the battery pack 3 in FIG.

[0115] 15, an automobile 5 according to an embodiment of the present invention may be, for example, an electric automobile, a hybrid automobile, or a plug-in hybrid automobile, and includes a battery pack 3 according to an embodiment of the present invention. The automobile 5 includes a four-wheeled automobile and a two-wheeled automobile. The automobile 5 operates by receiving a supply of power from the battery pack 3 according to an embodiment of the present invention.

[0116] Although the present invention has been described above using limited embodiments and drawings, the present invention is not limited to these, and it goes without saying that various modifications and variations can be made by a person having ordinary knowledge in the technical field to which the present invention pertains within the technical spirit of the present invention and the scope of equivalents of the claims. [Explanation of symbols]

[0117] 5. Automobiles 3 Battery Pack 2-pack housing 1 battery cell 10 Electrode assembly 11 First plain area 12 Second plain area H1 Winding hole 20 Battery housing 21 Beading section 22 Crimping section 30 Current collector H2 collector hole 31 Support part 32 Tab joint 33 Housing joint 33a Contact part 33b Connection N groove F bending part S1 First state S2 Second state S3 Third state 40 Housing cover 41 Vent G1 seal gasket

Claims

1. An electrode assembly in which a first electrode, a second electrode, and a separator sandwiched therebetween are wound around a winding shaft to define a core and an outer peripheral surface, the first electrode including a first uncoated portion that is not coated with an active material layer along the winding direction; a battery housing having an opening on one side thereof and accommodating the electrode assembly through the opening; a current collector including a support portion disposed on an upper portion of the electrode assembly; a tab connecting portion extending from the support portion and connected to the first plain portion; and a housing connecting portion extending from the support portion and electrically connected to an inner surface of the battery housing, the length of the housing connecting portion being extensible; Including, battery cells.

2. The boundary area between the support portion and the housing coupling portion is The battery cell according to claim 1 , wherein an end of the housing joint portion is bent so as to face the opening and the inner surface of the battery housing.

3. The housing coupling portion is The battery cell according to claim 1 , wherein the electrode assembly extends in a winding axial direction and a radial direction.

4. The housing coupling portion is contacts coupled onto an inner surface of the battery housing; a connection portion that connects the support portion and the contact portion; 10. The battery cell of claim 1, comprising:

5. The housing coupling portion is The battery cell of claim 1 , wherein the battery cell is configured so that its length is reducible.

6. At least a portion of the housing coupling portion is The battery cell of claim 1 , wherein the battery cell has a rim shape with a hollow center.

7. At least a portion of the housing coupling portion is The battery cell according to claim 1 , wherein the planar shape is an oval shape.

8. At least a portion of the housing coupling portion is The battery cell according to claim 1 , wherein the planar shape is a polygon.

9. The battery cell according to claim 4 , wherein the outer circumferential edge of the connection portion is provided with at least one groove that curves inward toward the inside of the connection portion.

10. The connection portion is The battery cell of claim 4 comprising at least one fold.

11. The bent portion is The battery cell according to claim 10 , having a shape that is convex in a direction facing the opening.

12. The contact portion is The battery cell of claim 4 having a continuous shape along the inner surface of the cell housing.

13. A battery pack comprising at least one battery cell according to any one of claims 1 to 4.

14. A motor vehicle comprising at least one battery pack according to claim 13.

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