Current collectors, battery cells, battery modules, battery packs, and automobiles including the same.

Abstract

A battery cell according to one embodiment of the present invention is an electrode assembly in which a core and an outer surface are defined by winding a first electrode and a second electrode and a separator membrane interposed between them around a winding axis, wherein the first electrode includes an active material portion coated with an active material layer along the winding direction and a first plain portion not coated with an active material layer, and at least a portion of the first plain portion is used as an electrode tab by itself, the electrode assembly and a battery housing housing the electrode assembly through an opening formed on one side, a tab coupling portion coupled to the first plain portion, and a housing coupling portion extending from the tab coupling portion and electrically coupled to the inner surface of the battery housing, the housing coupling portion having at least one notch portion, the current collector.

Description

Technical Field

[0001] The present invention relates to a current collector, a battery cell, a battery module, a battery pack, and a vehicle including the same. This application claims priority based on Korean Patent Application No. 10-2023-0191777 filed on December 26, 2023, Korean Patent Application No. 10-2024-0025957 filed on February 22, 2024, and Korean Patent Application No. 10-2024-0067268 filed on May 23, 2024, and all contents disclosed in the specifications and drawings of said applications are hereby incorporated in their entirety into this application.

Background Art

[0002] Secondary batteries that are easy to apply according to product groups and have electrical characteristics such as high energy density are universally applied not only to portable devices but also to electric vehicles (EV: Electric Vehicle) or hybrid electric vehicles (HEV: Hybrid Electric Vehicle) driven by an electric drive source. Such secondary batteries are attracting attention as a new energy source that is environmentally friendly and improves energy efficiency, as they not only have the main advantage of dramatically reducing the use of fossil fuels, but also have the advantage of producing no by-products from energy use at all.

[0003] Types of secondary batteries that are currently widely used include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and the like. The operating voltage of such a unit secondary battery cell, that is, a unit battery cell, is approximately 2.5V to 4.5V. Therefore, when a higher output voltage than this is required, a plurality of battery cells may be connected in series to constitute a battery pack. In addition, a plurality of battery cells may be connected in parallel to constitute a battery pack according to the charge and discharge capacity required for the battery pack. Accordingly, the number of battery cells included in the battery pack can be variously set according to the required output voltage and / or charge and discharge capacity.

[0004] On the other hand, the current collectors included in conventional battery cells are designed as four-way blades and are welded to the CBD flat section. Therefore, in the worst case during welding, there is a concern about the inflow of welding spatter, which is one of the main control items for welding. Depending on the wall thickness tolerance of the can raw material, the tolerance of the flat section of the upper beading neck, and the welding alignment tolerance, if welding is performed on the floating area between the bend position at the top of the beading neck and the current collector, there is a problem of spatter inflow. [Overview of the project] [Problems that the invention aims to solve]

[0005] Therefore, one objective of the present invention is to reduce the size of the laser emission unit by forming a notch at the contact portion of the current collector contained inside the battery cell, thereby enabling welding to be performed at localized locations.

[0006] Furthermore, the present invention also aims to reduce the power of the laser beam and improve welding performance.

[0007] Furthermore, the present invention also aims to reduce the inflow of sputter during the manufacturing process.

[0008] Furthermore, the present invention aims to reduce welding back bead.

[0009] However, the technical problems that this invention aims to solve are not limited to those mentioned above, and other problems not mentioned will be clearly understood by an ordinary person of the art from the description of the invention below. [Means for solving the problem]

[0010] A battery cell according to one embodiment of the present invention for solving the above problems comprises an electrode assembly in which a core and an outer surface are defined by winding a first electrode and a second electrode and a separator membrane interposed between them around a winding axis, wherein the first electrode includes an active material portion coated with an active material layer along the winding direction and a first blank portion not coated with an active material layer, and at least a part of the first blank portion is used as an electrode tab by itself; a battery housing housing the electrode assembly through an open portion formed on one side; a current collector including a tab coupling portion coupled to the first blank portion and a housing coupling portion extending from the tab coupling portion and electrically coupled to the inner surface of the battery housing, the housing coupling portion being provided with at least one notch portion.

[0011] The battery housing may have a beading portion formed at the end adjacent to the opening, which is recessed inward.

[0012] In one embodiment of the present invention, the housing coupling portion may include a contact portion that is coupled onto the beading portion of the battery housing, and a connecting portion that connects the tab coupling portion and the contact portion.

[0013] Here, the notched portion may be provided on the contact portion.

[0014] In another embodiment of the present invention, the notch portion may be configured to be irradiated with a laser beam.

[0015] The width of the notch portion may be configured to be 10% to 90% of the width of the laser beam.

[0016] In yet another embodiment of the present invention, the notch may extend in a direction perpendicular to the radial direction of the battery cell.

[0017] In yet another embodiment of the present invention, the notches may be provided in multiple locations within a single contact area.

[0018] For example, the notch portions may be arranged to be spaced apart at predetermined intervals in the radial direction of the battery cell.

[0019] In still another aspect of the present invention, a plurality of the notch portions may be configured to be included within the width of the laser beam.

[0020] In one aspect of the present invention, the notch portion may be located on the flat upper surface of the beading portion.

[0021] In another aspect of the present invention, the contact portion may be provided with a weld bead formed by laser beam irradiation.

[0022] The notch portion may be formed by partially reducing the thickness of the housing coupling portion by notching a predetermined portion of the housing coupling portion.

[0023] The notch portion is located on the flat upper surface of the beading portion, and the center of the weld bead may be positioned inward with reference to the center of the flat upper surface of the beading portion.

[0024] In still another aspect of the present invention, the width of the weld bead may be configured to be 10% to 35% with respect to the press-fitting depth of the beading portion.

[0025] Meanwhile, the present invention provides a battery pack, which includes at least one battery cell according to the present invention.

[0026] Furthermore, the present invention provides a vehicle, which includes at least one battery pack according to the present invention. Advantageous Effects of the Invention

[0027] According to the present invention, by providing the notch portion at the contact portion of the current collector included in the cylindrical battery cell, smooth welding can be achieved even at a local site.

[0028] Furthermore, according to the present invention, the size of the laser beam can be reduced.

[0029] Furthermore, according to the present invention, it is possible to reduce the power of the laser beam and improve welding performance.

[0030] Furthermore, according to the present invention, the inflow of spatter during the process can be reduced.

[0031] Furthermore, according to the present invention, welding back beads can be reduced.

[0032] However, the effects obtained by the present invention are not limited to the above-mentioned effects, and other technical effects not mentioned will be clearly understood by a person of ordinary skill in the art from the following description of the invention.

[0033] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention together with the detailed description of the invention. Therefore, the present invention should not be construed as being limited only to the matters described in the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] [Figure 1] It is a diagram for explaining a battery cell according to an embodiment of the present invention. [Figure 2] It is a longitudinal cross-sectional perspective view of the battery cell of Figure 1. [Figure 3] It is a longitudinal cross-sectional view of the battery cell of Figure 1. [Figure 4] It is a plan view for explaining a current collector according to an embodiment of the present invention. [Figure 5] It is a diagram for explaining a state where the current collector of Figure 4 is seated on the beading portion. [Figure 6] It is an enlarged view of the contact portion of the current collector of Figure 4. [Figure 7] It is an enlarged view of the notch portion and the weld bead at the contact portion of Figure 6. [Figure 8] This diagram illustrates the relationship between the notch portion provided on the current collector in Figure 4 and the laser beam. [Figure 9] Figure 4 is a side cross-sectional view illustrating the state in which the current collector is securely attached to the beading section. [Figure 10] This figure illustrates a comparative example of the present invention. [Figure 11] This is a diagram illustrating the formation position of a weld bead on a current collector according to one embodiment of the present invention. [Figure 12] This is a diagram illustrating a battery pack including a battery cell according to one embodiment of the present invention. [Figure 13] Figure 12 is a diagram illustrating an automobile including a battery pack. [Modes for carrying out the invention]

[0035] Preferred embodiments of the present invention will now be described in detail with reference to the attached drawings. Prior to this, terms and words used herein and in the claims shall not be interpreted in their ordinary and dictionary sense, but in accordance with the principle that the inventor himself may appropriately define the concept of a term in order to best describe the invention, and shall be interpreted in a sense and concept that is appropriate to the technical idea of ​​the present invention. Accordingly, the configurations shown in the embodiments described herein are merely one of the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and it should be understood that there may be a variety of equivalents and modifications that can be substituted therein at the time of this application.

[0036] Furthermore, for the sake of understanding the invention, the accompanying drawings are not shown to actual scale, and the dimensions of some components may be exaggerated. Also, the same component may be assigned the same reference numeral in different embodiments.

[0037] The statement that two comparison objects are identical means that they are "substantially identical." Therefore, substantially identical objects may include those with deviations considered low in this industry, for example, deviations of 5% or less. Also, in a given domain, the uniformity of a parameter may mean that it is uniform in terms of the average.

[0038] While terms like "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited to these terms. These terms are used solely to distinguish one component from another, and unless otherwise stated, the first component is also the second component.

[0039] Throughout the specification, unless otherwise stated, each component may be singular or plural.

[0040] To say that any configuration is placed "above (or below)" or "above (or below)" a component means not only that the configuration is placed in contact with the upper (or lower) surface of the above component, but that another configuration may be interposed between the above component and any configuration placed on (or below) it.

[0041] Furthermore, when it is stated that one component is “linked,” “joined,” or “connected” to another component, please understand that while the above components may be directly linked or connected to each other, there may also be other components “interposed” between them, or each component may be “linked,” “joined,” or “connected” through other components.

[0042] Throughout the specification, "A and / or B" means A, B, or A and B unless otherwise specified, and "C to D" means C or above and D or below unless otherwise specified.

[0043] For the sake of explanation, in this specification, the direction along the longitudinal direction of the winding axis of an electrode assembly 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 around direction. The direction approaching or moving away from the winding axis is referred to as the radial direction. Of these, the direction approaching the winding axis is specifically referred to as the centripetal direction, and the direction moving away from the winding axis is referred to as the centrifugal direction.

[0044] Figure 1 is a diagram illustrating a battery cell according to one embodiment of the present invention, and Figure 2 is a longitudinal cross-sectional perspective view of the battery cell in Figure 1. Figure 3 is a longitudinal cross-sectional view of the battery cell in Figure 1.

[0045] Referring to Figures 1 to 3, a battery cell 1 according to one 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 and / or terminals 50 and / or a sealing gasket G1 and / or a second current collector 60 and / or an insulator 70. The present invention is not limited by the shape of the battery and is applicable to other shapes of batteries, such as prismatic batteries.

[0046] The electrode assembly 10 comprises a first blank portion 11 and a second blank portion 12. More specifically, the electrode assembly 10 has a structure in which the core and outer surface are defined by winding the first electrode and the second electrode, and the separating membrane interposed between them, around a winding axis (having a direction parallel to the Z-axis direction), with a separating membrane interposed between them. That is, the electrode assembly 10 applied to the present invention may be a jelly roll type electrode assembly 10. In this case, an additional separating membrane may be provided on the outer surface of the electrode assembly 10 for insulation from the battery housing 20. The electrode assembly 10 may have a winding structure known in the art without limitation.

[0047] In the electrode assembly 10, the first blank portion 11 and the second blank portion 12 are arranged in opposite directions. Furthermore, the first blank portion 11 and the second blank portion 12 are exposed to the outside of the separation membrane. In such an electrode assembly 10, only a portion of the first blank portion 11 and the second blank portion 12 can be defined and used as electrode tabs.

[0048] 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. One end of the first electrode in the width direction (the direction parallel to the height direction of the battery cell 1 shown in Figure 1, the Z-axis direction) has a plain area where the first electrode active material is not coated. That is, the first electrode includes a plain area at the end of its long side along the winding direction, which is not coated with the active material and is exposed to the outside of the separation membrane. The plain area that functions as the first electrode tab will be referred to below as the first plain area 11. The first plain area 11 is provided at the top 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 Figure 1). That is, the first electrode includes a first plain area 11 at the end of its long side, which is not coated with the active material layer and is exposed to the outside of the separation membrane, and at least a portion of the first plain area 11 is used as an electrode tab by itself. The first blank portion 11 may be, for example, a negative electrode tab. In this case, the first electrode is a negative electrode plate.

[0049] On the other hand, at least a portion of the first plain portion 11 may include a plurality of segmented pieces divided along the winding direction of the electrode assembly 10. In this case, the plurality of segmented pieces may be bent along the radial direction of the electrode assembly 10 (a direction perpendicular to the Z-axis direction, for example, the X-axis direction).

[0050] Referring to Figures 2 and 3, the multiple segmented pieces of the folded first plain section 11 can overlap to form a folded surface. In this case, the tab joint 32 of the current collector 30, which will be described later, can be joined to the folded surface. The tab joint 32 can be joined to the region where the multiple segmented pieces overlap. In this case, welding can be performed to a certain region while the tab joint 32 is firmly attached to the folded surface of the first plain section 11. That is, the tab joint 32 can be joined to the region where the multiple segmented pieces of the first plain section 11 overlap. For example, as can be seen from Figure 5, the tab joint 32 can have at least one welded portion welded to a certain region while firmly attached to the folded surface of the first plain section 11.

[0051] 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. At the other end of the second electrode in the width direction (parallel to the height direction of the battery cell 1 shown in Figure 1), there is a plain area where the second electrode active material is not coated. That is, the second electrode includes a plain area at the end of its long side along the winding direction, which is not coated with the active material and is exposed to the outside of the separator membrane. The plain area that functions as a second electrode tab will be referred to below as the second plain area 12. The second plain area 12 is located at the bottom of the electrode assembly 10 in the height direction, housed in the battery housing 20. That is, the second electrode includes a second plain area 12 at the end of its long side, which is not coated with the active material layer and is exposed to the outside of the separator membrane, and at least a portion of the second plain area 12 is used as an electrode tab by itself. The second plain area 12 may be, for example, a positive electrode tab. In this case, the second electrode is a positive electrode plate.

[0052] On the other hand, in 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 can be used without limitation as long as they are active materials well known in the art. Preferably, the battery cell 1 may be, for example, a cylindrical secondary battery with a form factor ratio (height to diameter ratio) greater than about 0.4. Preferably, the diameter of the cylindrical secondary battery is 40 mm to 50 mm and the height is 60 mm to 130 mm. The form factor of the battery cell 1 may be, for example, 46110, 4875, 48110, 4880, or 4680.

[0053] Referring to Figures 1 to 3, the battery housing 20 is a substantially cylindrical housing with an open portion formed on one side, and is made of a conductive metallic material. In one example, the battery housing 20 may be made of iron, nickel-plated iron, or stainless steel (SUS) and may be a battery can, but the present invention is not limited thereto. The side surface of the battery housing 20 and the bottom surface located opposite the open portion are generally formed integrally. That is, the battery housing 20 generally has an open upper end in the height direction (Z-axis direction) and a closed lower end. The bottom surface of the battery housing 20 may have a substantially flat shape. The battery housing 20 houses the electrode assembly 10 through the open portion formed on one side in the height direction. The battery housing 20 can also house the electrolyte through the open portion.

[0054] The battery housing 20 may include a beading portion 21 formed at the end adjacent to an open portion provided at the upper 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 outer circumferential surface of the battery housing 20 is recessed to a predetermined depth. More specifically, the beading portion 21 may have a shape in which it is recessed inward in the region between the open portion formed on one side of the battery housing 20 and the housing portion that accommodates the electrode assembly 10.

[0055] The beading portion 21 is formed on the upper part of the electrode assembly 10. The inner diameter of the battery housing 20 in the region where the beading portion 21 is formed is 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 below the beading portion 21.

[0056] The beading portion 21 provides a support surface to which the housing cover 40 can be securely attached. Furthermore, the beading portion 21 can provide a support surface to which at least a portion of the periphery of the current collector 30, which will be described later, can be securely attached and joined. That is, at least a portion of the periphery of the current collector 30 of the present invention and / or the periphery of the housing cover 40 can be securely attached to the upper surface of the beading portion 21. In order to stably support at least a portion of the periphery of the current collector 30 and / or the periphery of the housing cover 40, the upper surface of the beading portion 21 may have a shape that extends along a direction substantially parallel to the lower surface of the battery housing 20, that is, along a direction substantially perpendicular to the side wall of the battery housing 20.

[0057] The beading portion 21 prevents the electrode assembly 10, which has a size substantially corresponding to the inner diameter of the battery housing 20, from coming out through the opening formed at the upper end of the battery housing 20, and can also function as a support portion to which the housing cover 40 is securely attached. The beading portion 21 can function as a support portion not only for the housing cover 40, but also for fixing the contact portion 33a of the current collector 30, the seal gasket G1, and the like.

[0058] The crimping portion 22 is formed on the upper part of the beading portion 21. The crimping portion 22 has a shape that extends or is bent to surround the periphery of the housing cover 40 which is positioned on the upper part of the beading portion 21. This shape of the crimping portion 22 fixes the housing cover 40 on the beading portion 21.

[0059] Next, with reference to Figures 1 to 11, the current collector 30 according to an embodiment of the present invention will be described in detail in comparison with a conventional current collector.

[0060] First, referring to Figures 1 to 3, the current collector 30 according to one embodiment of the present invention is housed inside the battery housing 20, electrically connected to the electrode assembly 10, and also electrically connected to the battery housing 20. That is, the current collector 30 electrically connects the electrode assembly 10 and the battery housing 20.

[0061] Figure 4 is a diagram illustrating a current collector according to one embodiment of the present invention, and Figure 5 is a diagram illustrating the state in which the current collector of Figure 4 is fixedly attached to the beading portion.

[0062] Referring to Figures 4 and 5, the current collector 30 includes a support portion 31 located on one surface of the electrode assembly 10, a tab coupling portion 32 extending from the support portion 31 and coupled to the first blank portion 11, and a housing coupling portion 33 extending from the support portion 31 and coupled to the inner surface of the battery housing 20.

[0063] 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 of the present invention, the possibility of damage occurring at the coupling portion between the current collector 30 and the electrode assembly 10, and at the coupling portion between the current collector 30 and the battery housing 20 can be minimized.

[0064] Referring again to Figure 4, the housing coupling portion 33 is provided with at least one notch portion N. A laser beam can be irradiated onto the notch portion N. This allows the housing coupling portion 33 and the inner surface of the battery housing 20 to be welded together.

[0065] Thus, according to the present invention, by providing at least one notch portion N in the housing joint portion 33 of the current collector 30, welding of localized areas of the housing joint portion 33 can be performed smoothly. In other words, in the present invention, by providing the notch portion N, the laser is irradiated around the notch portion N, so the probability of welding defects can be significantly reduced. Furthermore, with the above configuration, welding performance is improved, eliminating the need to set the laser beam power unnecessarily high. In other words, according to the present invention, the size of the laser beam emission unit and the laser beam power can be reduced, and an improvement in welding performance can be expected.

[0066] For example, if the power of the welding laser is excessively high, impurities called back beads will form on the back surface of the weld. However, with the above-described configuration of the present invention, the power of the laser beam can be reduced, thus preventing the formation of back beads.

[0067] Referring to Figure 4, at least one tab coupling portion 32 and / or housing coupling portion 33 may be provided. At least one tab coupling portion 32 and at least one housing coupling portion 33 may be arranged, for example, substantially radially, crosswise, or in a combination thereof, with respect to the center of the current collector 30. In other embodiments, each of the multiple housing coupling portions 33 may be arranged between adjacent tab coupling portions 32.

[0068] Referring to Figure 3, the support portion 31 and the plurality of tab coupling portions 32 are positioned on the upper part of the electrode assembly 10. The tab coupling portions 32 are coupled to the first blank portion 11 of the electrode assembly 10. The tab coupling portions 32 can be coupled to the first blank portion 11 by welding, for example, along the radial direction of the electrode assembly 10. The tab coupling portions 32 can be welded to the first blank portion 11, for example, in a manner substantially parallel to the lower surface of the battery housing 20. On the other hand, not only the tab coupling portions 32 but also the support portion 31 can be coupled to the first blank portion 11.

[0069] The current collector 30 may be made of the same metal as the first electrode current collector, or a material that can be easily welded to it. For example, it may be copper or a copper alloy, nickel or a nickel alloy, iron, stainless steel, or a composite material thereof.

[0070] The support portion 31 may be provided with a current collector hole H2 formed at a position corresponding to the winding hole H1 formed in the approximate center of the electrode assembly 10. The winding hole H1 and the current collector hole H2, which communicate with each other, can function as a passage for inserting a welding rod for welding the terminal 50 and the second current collector 60, or for welding the terminal 50 and a lead tab (not shown), or for irradiating a laser beam. The current collector hole H2 may have a diameter substantially the same as or larger than the winding hole H1 of the electrode assembly 10 so as not to cover 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 covered, reducing the ability to inject liquid, and it may become difficult to secure sufficient space for inserting welding equipment or irradiating a laser.

[0071] The multiple tab coupling portions 32 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 tab coupling portions 32 may be located spaced apart from one another along the perimeter of the support portion 31.

[0072] The multiple housing coupling portions 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 coupling portions 33 may be located spaced apart from one another along the perimeter of the support portion 31. At least one housing coupling portion 33 may be located between adjacent tab coupling portions 32.

[0073] Referring to Figure 5, the housing coupling portion 33 can 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 can be coupled to the inner surface of the battery housing 20, for example, the beading portion 21. In particular, the housing coupling portion 33 can be coupled to the upper surface of the beading portion 21.

[0074] In the battery cell 1 of the present invention, the housing coupling portion 33 can be securely attached to the beading portion 21 by the step of housing the electrode assembly 10 with the current collector 30 attached into the battery housing 20. Therefore, the welding process between the battery housing 20 and the current collector 30 can be easily carried out. For example, as can be seen from Figure 5, at least one weld bead BW may be included between the beading portion 21 and the housing coupling portion 33. That is, the current collector 30 may include at least one weld bead BW that is welded to the inner surface of the battery housing 20. For welding to join the battery housing 20 and the current collector 30, for example, laser welding, ultrasonic welding, or spot welding can be applied. Furthermore, by having the upper surface of the beading portion 21 have a shape that extends in a direction substantially parallel to the lower surface of the battery housing 20, that is, in a direction substantially perpendicular to the side wall of the battery housing 20, and by having the housing coupling portion 33 have a shape that extends in the same direction, that is, in the radial and circumferential directions, the housing coupling portion 33 can be stably contacted onto the beading portion 21. In addition, by having the housing coupling portion 33 stably contact the beading portion 21 in this way, welding between the two parts can be performed smoothly, thereby improving the bonding strength between the two parts and minimizing the increase in resistance at the joint.

[0075] Referring to Figures 4 and 5, the housing coupling portion 33 may include a contact portion 33a that connects to the inner surface of the battery housing 20, and a connecting portion 33b that connects the support portion 31 and the contact portion 33a. In one embodiment of the present invention, the tab coupling portion 32 may have a greater width than the connecting portion 33b. In another embodiment of the present invention, the contact portion 33a may have a greater width than the connecting portion 33b. Here, "width" refers to the dimension in the direction perpendicular to the radial direction.

[0076] The contact portion 33a is coupled to the inner surface of the battery housing 20. Preferably, the contact portion 33a can be coupled to the beading portion 21 of the battery housing 20. In this case, for stable contact and coupling, both the beading portion 21 and the contact portion 33a may have a shape that extends in a direction substantially parallel to the lower surface of the battery housing 20, that is, in a direction substantially perpendicular to the side wall of the battery housing 20.

[0077] The contact portion 33a may have an arc shape that extends circumferentially along the beading portion 21 of the battery housing 20, at least in part. This allows the circumferential extension length L_33a of the contact portion 33a to be longer than the width L_33b of the connecting portion 33b. In this case, to maximize the contact area, the current collector 30 may be configured such that the sum of the circumferential extension lengths of the contact portions 33a of each of the multiple housing connecting portions 33 is substantially the same as, or slightly shorter than, the inner circumference of the battery housing 20. In another embodiment, the contact portion 33a may have an arc shape that extends circumferentially along the beading portion 21 in opposite directions from the intersection of the connecting portion 33b and the contact portion 33a.

[0078] Referring to Figure 4, the current collector 30 of the present invention may be provided with at least one electrolyte injection hole H3. The electrolyte injection hole H3 may be provided, for example, in a tab coupling portion 32. When there are multiple tab coupling portions 32, the electrolyte injection hole H3 may be provided in at least one tab coupling portion 32. Referring to Figures 3 and 4, when manufacturing a battery cell 1 according to one embodiment of the present invention, the electrolyte can be injected after the coupling including the electrode assembly 10 and the current collector 30 is housed in the battery housing 20. At this time, the electrolyte injection efficiency may be improved by the electrolyte injection hole H3. Multiple electrolyte injection holes H3 may be provided in a single tab coupling portion 32. Multiple electrolyte injection holes H3 may be arranged substantially symmetrically with respect to the widthwise center of the tab coupling portion 32.

[0079] It is preferable to perform laser welding for joining the battery housing 20 and the current collector 30. Applying laser welding is advantageous not only for ensuring quality and performance by preventing deformation caused by contact pressure welding such as resistance welding, but also for improving product yield. Furthermore, since there is no need to replace welding rods or horns, it is advantageous for improving production efficiency and reducing production costs, and the manufacturing process time can be shortened. Laser welding offers higher joint strength compared to ultrasonic welding and can also ensure uniformity of welding performance and quality compared to resistance welding. The laser beam reaches the surface of the contact portion 33a, which is the workpiece, directly from the top downwards of the battery housing 20. The laser welding apparatus may consist of a laser light source (laser beam source) and a laser emission unit which may include optical components such as a collimator, lens, and mirror for focusing the laser from the laser light source and irradiating the workpiece with a laser beam of a predetermined spot diameter, and a system for introducing welding atmosphere gas and discharging by-products. The spot diameter refers to the diameter at the focal point. While welding can be performed in air, it is sometimes desirable to partially introduce an inert gas such as nitrogen (N2) or argon (Ar), and a welding atmosphere gas supply system including an inert gas supply unit may be included. Furthermore, a by-product discharge system including a dust collection unit for suction and removal of welding fumes may be included to remove welding fumes.

[0080] Figure 6 is an enlarged view of the contact area of ​​the current collector in Figure 4, and Figure 7 is an enlarged view of the notch and weld bead of the contact area in Figure 6. The lower part of Figure 7 shows the A-A' cross section in the upper part. Figure 8 is a diagram illustrating the relationship between the notch provided on the current collector in Figure 4 and the laser beam.

[0081] Referring to Figures 4 to 6, the notch portion N may be provided on the contact portion 33a. A laser beam can be irradiated onto the notch portion N. This allows the contact portion 33a and the inner surface of the battery housing 20 to be welded together. More preferably, the contact portion 33a and the beading portion 21 can be welded together. That is, a weld bead BW can be formed between the contact portion 33a and the beading portion 21 by irradiation with a laser beam.

[0082] A weld bead typically refers to the deposited metal formed by a single welding pass (a single laser beam pass), and is also called a weld spot. The size, shape, position, and overlap of the weld bead can vary depending on the welding conditions. In this specification, the term weld bead (BW) is used to refer to the welded portion, including not only weld beads that are formed separately and distinguishable from one another, but also cases where weld beads overlap to form a single mass. Methods for forming the weld bead (BW) include wobble welding, spot welding, weaving (hatching) welding, and scan welding.

[0083] With this structure, by providing at least one notch portion N in the contact portion 33a of the current collector 30, welding can be performed smoothly even on localized areas of the contact portion 33a. In other words, in the present invention, by providing the notch portion N, the laser is irradiated around the notch portion N, so the probability of welding defects can be significantly reduced. Furthermore, with the above configuration, welding performance is improved, eliminating the need to set the laser beam power unnecessarily high. In other words, according to the present invention, the size of the laser beam emission unit and the laser beam power can be reduced, and an improvement in welding performance can be expected.

[0084] Referring to Figures 7 and 8, the notch portion N can refer to a portion of the current collector 30 formed by cutting out a specific part of the current collector 30, particularly the housing coupling portion 33, and especially the contact portion 33a, thereby partially reducing the thickness of the contact portion 33a. However, the notch portion N here is not limited to notches formed by notching in the dictionary sense, but can also refer to spaces formed by cutting or pressing the current collector 30 by other methods, and if the current collector 30 is manufactured by casting, it can also be used to include grooves integrally formed inside the current collector 30 by the casting shape. In addition to notches, the notch portion N can also refer to grooves or trench-shaped recesses that are recessed inward from the upper surface of the contact portion 33a of the current collector 30. The depth d_N of the notch portion N is less than or equal to the thickness d_33a of the contact portion 33a. Preferably, the depth d_N of the notch portion N can be 50% or less of the thickness d_33a of the contact portion 33a. The cross-sectional shape of the notch N could be a V-shape triangle, based on the dictionary definition of "notch," but it can also include other shapes such as trapezoids, rectangles, semi-ellipses, and semicircles. Furthermore, by rounding the corners at both lower ends of the notch N, it is possible to prevent stress concentration at the corners during notching and the occurrence of cracks.

[0085] The length L_BW of the weld bead BW is a dimension in a direction substantially perpendicular to the radial direction of the battery cell 1, formed along the irradiation direction of the laser beam, and is approximately 1 mm to 3 mm. The length L_N of the notch portion N is also a dimension in a direction substantially perpendicular to the radial direction of the battery cell 1, and may be less than or equal to the length L_BW of the weld bead BW.

[0086] The width B of the weld bead BW is the radial dimension of the battery cell 1 and is approximately 0.3 mm to 1 mm. The width S of the notch portion N is also the radial dimension of the battery cell 1 and is smaller than the width B of the weld bead BW.

[0087] The dimensions and shape of the weld bead BW are not limited as long as the joint strength is maintained. Regarding the joint strength, the tensile force at the joint between the current collector 30 and the battery housing 20 by the weld bead BW is 2 kgf or more, preferably 3 kgf to 15 kgf, and more preferably 5 kgf to 15 kgf. Tensile force is a force applied perpendicular to the joint surface. It can be converted to tensile strength by multiplying it by the size of the surface on which the force acts. When the tensile force is 2 kgf or more, preferably 3 kgf or more, it does not affect the performance of the battery cell 1 when the battery cell 1 is used, and the current collector 30 does not detach from the battery housing 20 due to vibration or pressure of the equipment that occurs during the process.

[0088] It is desirable to increase the tensile strength as much as possible within the allowable range by optimally selecting the welding method. Since the joint strength in terms of tensile strength is also related to the area and depth of the weld bead BW (D_BW in Figure 11), the joint strength can be adjusted by adjusting the area and depth of the weld bead BW. As shown in the cross-section in Figure 11, the weld bead BW does not exist only on the surface, but needs to be formed on the contact surface of the two members joined by welding, and has a three-dimensional shape with thickness. The depth of the weld bead BW can be adjusted by the laser beam output, irradiation time, etc. The depth of the weld bead BW increases as the laser beam output increases and as the irradiation time increases. The laser beam output and irradiation time can be adjusted so that the weld bead BW does not extend and form too deeply so that it is exposed to the outer surface of the beading portion 21, while maintaining appropriate joint strength. In the actual process, since the thickness range of the current collector 30 and the battery housing 20 is fixed, it is necessary to adjust the laser beam depth to a level that prevents over-welding. In this invention, by providing at least one notch portion N in the contact portion 33a of the current collector 30, welding is performed on a localized area of ​​the contact portion 33a, thereby allowing the laser beam depth to be reduced. Since a shallow laser beam depth can be achieved using a low-power laser beam, manufacturing costs can be reduced and welding spatter generation can be minimized. A shallow laser beam depth can also be achieved by shortening the irradiation time, thus shortening manufacturing time and improving productivity.

[0089] In one aspect of the present invention, the width S of the notch portion N may be in the range of approximately 10% to 90% of the width L of the laser beam. Here, the width L of the laser beam may mean the spot diameter. The spot diameter of the laser beam is 10 μm to 200 μm. If the spot diameter of the laser beam exceeds 200 μm, the effect on corrosion increases and the aspect ratio of the weld bead BW decreases, resulting in the disadvantage of reduced welding efficiency. Also, if the laser beam size is less than 10 μm, the area to be welded is small, and sufficient joint strength cannot be secured in a single weld, which is a disadvantage. Therefore, it is desirable that the laser beam spot diameter meets the above range. Preferably, the spot diameter of the laser beam is about 50 μm.

[0090] For example, referring to Figure 8, the width S of the notch portion N can be configured to be smaller than the width L of the laser beam. In other words, any structure in which the width S of the notch portion N is included within the width L of the laser beam falls within the scope of the present invention. If the width S of the notch portion N is larger than the width L of the laser beam, it can no longer function as a notch portion N. This is because the notch portion N functions as a guideline for the laser beam to be irradiated during welding, and in order to perform such a function, it must be smaller than the width L of the laser beam.

[0091] On the other hand, if the width S of the notch portion N is less than approximately 10% of the width L of the laser beam, the size of the notch portion N becomes too small, which may make it difficult to detect the notch portion N for welding. In another embodiment, if the width S of the notch portion N is greater than approximately 90% of the width L of the laser beam, the size of the notch portion N becomes too large, almost the same as the width L of the laser beam, resulting in a large displacement of the weld bead BW. For example, the center of the laser beam is located within the notch portion N, and if the width of the notch portion N itself becomes too wide, the area in which the center of the laser beam can be located becomes wider. As a result, the displacement of the weld bead BW becomes large, which may make it difficult to secure an accurate welding position. Therefore, it is desirable to configure the notch portion S to be within the range of approximately 10% to 90% of the width L of the laser beam.

[0092] In another embodiment of the present invention, the notch portion N may be configured to extend in a direction substantially perpendicular to the radial direction of the battery cell 1. For example, referring to Figures 6 to 8, the notch portion N may be configured to have a linear shape extending in a direction substantially perpendicular to the radial direction of the battery cell 1. This allows the weld bead BW to form a linear weld pattern having a length L_BW extending substantially circumferentially on the beading portion 21. Alternatively, in another embodiment, the notch portion N may be configured to have a substantially arc shape substantially perpendicular to the radial direction of the cylindrical battery cell 1. This allows at least one weld bead BW formed between the beading portion 21 and the contact portion 33a to form an arc-shaped weld pattern extending substantially circumferentially on the beading portion 21. The weld bead BW formed on the contact portion 33a may have a shape extending circumferentially.

[0093] If the notched portion N extends in a direction substantially parallel to the radial direction of the battery cell 1, the welding length may be shortened, and sufficient welding performance may not be ensured. Furthermore, if the notched portion N extends in a direction substantially parallel to the radial direction of the battery cell 1, the number of welds required to ensure the necessary welding strength will increase. As a result, the efficiency of the process may decrease. On the other hand, according to the present invention, if the notched portion N extends in a direction substantially perpendicular to the radial direction of the battery cell 1, the process efficiency can be improved.

[0094] In yet another aspect of the present invention, the notches N may be provided in multiple locations within a single contact area 33a. For example, two or more may be provided. For example, referring to Figures 6 to 8, the notches N may be provided in multiple locations within a single contact area 33a in a direction substantially perpendicular to the radial direction of the battery cell 1. Preferably, the notches N may be arranged at predetermined intervals in the radial direction of the battery cell 1. For example, referring to Figure 7, the notches N may be provided in multiple locations with a spacing pitch P. Welding is applied to the notches N, and misalignment may occur with each weld. In this case, providing multiple notches N minimizes the misalignment of the final weld bead BW compared to a structure with only one notch N.

[0095] For example, the notched portion N may be configured to include multiple notches within the width L of the laser beam. This allows for the creation of multiple welding points within a single laser beam. To achieve this, the width S of the notched portion N must be smaller than the width L of the laser beam. As described above, it is desirable that the width S of the notched portion N be in the range of approximately 10% to 90% of the width L of the laser beam.

[0096] Because alignment deviations can exist in the welding area, it is difficult to weld the same spot each time, and the welding is controlled within a certain tolerance. When a laser beam is irradiated, welding is performed around the notch N, so providing multiple notches N can reduce welding defects. For example, even if welding is performed slightly off-center from the notch N due to alignment deviations, having multiple notches N can reduce defects such as reduced weld strength and weak welds compared to having only one notch N. Therefore, it is desirable to have multiple notches N.

[0097] Thus, the above structure of the present invention can significantly reduce the welding defect rate. Furthermore, a structure with multiple notches N can improve welding strength and prevent defects such as weak welding, so it is desirable to provide multiple notches N.

[0098] Furthermore, the width S and spacing pitch P of the notch portion N can be determined by considering the number of notch portions N that fit within the width B of the weld bead BW and the width L of the laser beam. For example, if there are n notch portions N, n × S + (n-1) × P can be made smaller than B, and S can be made smaller than P. The width S and spacing pitch P of the notch portion N can be designed to prevent damage to the current collector 30 when forming fine notch portions N, and to prevent crack formation and deformation.

[0099] Figure 9 is a side cross-sectional view illustrating the state in which the current collector of Figure 4 is fixed onto the beading portion, and Figure 10 is a diagram illustrating a comparative example of the present invention. Figure 11 is a diagram illustrating the formation position of a weld bead provided on a current collector according to one embodiment of the present invention.

[0100] In one embodiment of the present invention, the contact portion 33a may have a flat surface that is coupled to the upper surface of the beading portion 21 facing the open portion. Referring to Figures 9 to 11, the contact portion 33a can be fixed onto the flat upper surface of the beading portion 21. At this time, the notch portion N may be located on the flat upper surface of the beading portion 21. At this time, since laser welding is performed on the notch portion N, the contact portion 33a can be welded to the flat upper surface of the beading portion 21 by the laser beam. More specifically, the contact portion 33a may be provided with a weld bead BW formed by irradiation with a laser beam.

[0101] For example, referring to Figure 10, which corresponds to a comparative example of the present invention, a predetermined gap G may exist between the contact portion 33a of the housing joint portion 33 and the beading portion 21. More specifically, since the beading portion 21 has a shape in which the outer peripheral surface of the battery housing 20 is recessed by a predetermined depth D, the beading portion 21 has a predetermined flat section 21a, and in the vicinity of the innermost point of the beading portion 21, there is a curved surface region 21b having a predetermined radius of curvature. That is, from the point where the curved surface region 21b begins after the flat section 21a of the beading portion 21, the vertical distance from the contact portion 33a gradually increases as you move radially inward. In other words, as can be seen from Figure 10, there is a minute space such as a gap G between the contact portion 33a and the beading portion 21 that gradually widens as you move radially inward. At this time, as shown in Figure 10, when welding is performed in the region where the minute gap G is located and a weld bead BW' is formed, a problem occurs in which welding spatter flows in. Weld spatter refers to various impurities (dross) generated during welding, and is a general term for particles that adhere to or peel off the surface of the base material without becoming weld metal from the molten metal during welding. In this way, conventionally, there is a possibility that welding spatter may flow into the aforementioned fine spaces, which can act as a factor causing defects not only in the welding process but also in post-welding processes.

[0102] In the present invention, since a notch portion N is provided, a welding bead BW can be formed even if the laser beam power required to form a welding bead BW' without a conventional notch portion is reduced, or even if the size of the laser beam emission unit is reduced. Therefore, the generation of welding spatter can be reduced, and even if welding is performed in the area where the fine gap G is located, the problem of welding spatter flowing in can be greatly resolved. Furthermore, in the battery cell 1 according to one embodiment of the present invention, as can be seen from Figure 11, the notch portion N may be located on the flat upper surface of the beading portion 21. That is, the notch portion N is located within the flat section 21a of the beading portion 21, thereby allowing the contact portion 33a to be welded onto the flat upper surface of the beading portion 21 by the laser beam. Preferably, the width B of the welding bead BW formed between the contact portion 33a and the beading portion 21 may be formed to be smaller than the flat section 21a of the beading portion 21.

[0103] As a result, with this structure of the present invention, the formation position of the weld bead BW is adjusted so that welding is performed only in areas without a gap G between the contact portion 33a and the beading portion 21, thereby reducing the inflow of spatter during the process.

[0104] In another embodiment of the present invention, the center of the weld bead BW may be located inward with respect to the center of the flat upper surface of the beading portion 21.

[0105] For example, referring to Figure 11, the center C_BW of the weld bead BW may be located inward with respect to the center C_21a of the flat upper surface of the beading portion 21. That is, the weld bead BW may be positioned closer to the inside than to the outside in the radial direction within the flat section without a gap G between the contact portion 33a and the beading portion 21.

[0106] With this structure, welding is performed only in the gap-free region between the contact portion 33a and the beading portion 21, thus reducing the inflow of spatter during the process. Furthermore, because the welding area is closer to the radially inward direction, the welding strength between the beading portion 21 and the current collector 30 can be relatively improved. In other words, with this structure, the current collector 30 can maintain a more stable bond on the beading portion 21.

[0107] Since the flat section 21a of the beading portion 21 has a value determined according to the specifications of the battery cell 1, the position of the center C_21a on the flat upper surface of the beading portion 21 is a fixed value for the specified battery cell 1. In order to position the center C_BW of the weld bead BW inward from the position of the center C_21a on the flat upper surface of the beading portion 21, and to form the weld bead BW in a region without a gap G between the contact portion 33a and the beading portion 21, it is advantageous for the width B of the weld bead BW to be small. According to the present invention, since a notch portion N can be formed in the contact portion 33a of the current collector 30 and welding can be performed on a localized area, there is an advantage that the width B of the weld bead BW can be made smaller than the width of a conventional weld bead BW'. In yet another embodiment of the present invention, the weld bead BW can be formed between the contact portion 33a and the beading portion 21, and the width B of the weld bead BW can be configured to be smaller than the recess depth D of the beading portion 21. The width B of the weld bead BW may be, for example, greater than or equal to the width L of the laser beam.

[0108] For example, referring to Figure 11, the width B of the weld bead BW is smaller than the recess depth D of the beading portion 21. Preferably, the width B of the weld bead BW may be configured to be about 10% to 35% of the recess depth D of the beading portion 21. More preferably, the width B of the weld bead BW may be configured to be about 15% to 31.67% of the recess depth D of the beading portion 21. According to the above configuration of the present invention, sufficient weld strength can be ensured while maximizing the efficiency of the welding process.

[0109] The depth D_BW of the weld bead BW is 2mm to 4mm. If the welding laser power is excessively high, a back bead may occur on the back surface of the weld. In this invention, the notch portion N configuration allows for a reduction in the laser beam power, thereby preventing the occurrence of a back bead when forming a small weld bead BW with a depth of 2mm to 4mm.

[0110] Referring again to Figures 1 to 3, the housing cover 40 covers the opening formed on one side of the battery housing 20. The housing cover 40 can be fixed by a crimping portion 22 formed at the upper end of the battery housing 20. In this case, 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 order to improve the fixing force and the airtightness of the battery housing 20. In this case, the contact portion 33a and / or the second contact portion 33a may be interposed between the beading portion 21 of the battery housing 20 and the seal gasket G1. The contact portion 33a and / or the second contact portion 33a interposed between the beading portion 21 and the seal gasket G1 in this manner can be fixed by bending the crimping portion 22 that extends upward from the beading portion 21.

[0111] Referring to Figure 3, the terminal 50 is electrically connected to the second blank portion 12 of the electrode assembly 10 by passing through the battery housing 20 from the opposite side of the opening in the battery housing 20. The terminal 50 can pass through approximately the center of the lower surface of the battery housing 20. The terminal 50 can be electrically connected to the electrode assembly 10 by, for example, coupling to a second current collector 60 coupled to the second blank portion 12, or by coupling to a lead tab (not shown) coupled to the second blank portion 12. Therefore, the terminal 50 has the same polarity as the second electrode of the electrode assembly 10 and can function as the second electrode terminal T2. If the second blank portion 12 is a positive electrode tab, the terminal 50 can function as a positive electrode terminal.

[0112] Considering the polarity and function of such terminal 50, it is necessary to maintain an insulating state between terminal 50 and the battery housing 20, which has the opposite polarity. For this purpose, an insulating gasket can be applied between terminal 50 and the battery housing 20. Alternatively, insulation can also be achieved by coating a portion of the surface of terminal 50 with an insulating material.

[0113] For the same reason, the second blank section 12 and / or the second current collector 60 need to maintain an insulating state from the battery housing 20. For this purpose, an insulator 70 may be interposed between the second blank section 12 and the battery housing 20, and / or between the second current collector 60 and the battery housing 20. If the insulator 70 is applied, the terminal 50 can pass through the insulator 70 for electrical connection with the second blank section 12.

[0114] On the other hand, in the present invention, the outer surface 20a of the closed portion located opposite to the open portion at the upper end of the battery housing 20 can function as a first electrode terminal T1. When the first blank portion 11 is a negative electrode tab, the first electrode terminal T1 can be a negative electrode terminal. The battery cell 1 according to the present invention has a structure in which the terminal 50 exposed on the lower surface located opposite to the open portion of the battery housing 20 can be used as a second electrode terminal T2, and the remaining area of ​​the lower surface of the battery housing 20, excluding the area occupied by the terminal 50 (including the area where the insulating gasket is exposed if the insulating gasket is exposed outside the terminal 50 on the outer surface 20a of the closed portion), can be used as the first electrode terminal T1. Therefore, the battery cell 1 according to the present invention can simplify the electrical connection structure because it can connect both the positive and negative electrodes in one direction when electrically connecting multiple battery cells 1. Furthermore, the battery cell 1 according to the present invention has the advantage that it is possible to secure a sufficient area for welding components for electrical connection because it has a structure in which most of the lower surface located opposite to the open portion of the battery housing 20 can be used as an electrode terminal.

[0115] Referring again to Figures 2 and 3, the second current collector 60 is coupled to the lower part of the electrode assembly 10. The second current collector 60 is made of a conductive metallic material and is electrically coupled to the second blank portion 12.

[0116] Referring to Figure 12, 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 the above embodiment of the present invention are electrically connected, and a pack housing 2 that houses it. In the drawings of the present invention, for illustrative purposes, components such as busbars for electrical connection, cooling units, and power terminals are omitted. The plurality of battery cells 1 are arranged in a predetermined number of rows, and the terminals 50 exposed on the lower surface of each battery cell 1 are used as second electrode terminals T2, and the remaining area on the lower surface of the battery housing 20 is used as first electrode terminals T1. Therefore, when electrically connecting the plurality of battery cells 1, both the positive and negative electrodes can be connected in one direction, thus simplifying the electrical connection structure. This increases the number of battery cells 1 that can be mounted in the same space, improves energy density, and facilitates electrical wiring work. Therefore, due to its excellent space efficiency and high electrical wiring efficiency, it has a significant work improvement effect during the assembly process of electric vehicles, and during the assembly and maintenance of the battery pack 3.

[0117] Referring to Figure 13, the automobile 5 according to one embodiment of the present invention is, 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 automobile 5 includes four-wheeled vehicles and two-wheeled vehicles. The automobile 5 operates by receiving power from the battery pack 3 according to one embodiment of the present invention.

[0118] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it goes without saying that any person with ordinary skill in the art to which the present invention belongs can make various modifications and variations within the equivalent scope of the technical idea of ​​the present invention and the following claims. [Explanation of Symbols]

[0119] 5: Automobile 3: Battery pack 2: Pack Housing 1: Battery cell 10: Electrode Assembly 11: First blank section 12: Second blank section H1: Winding hole 20: Battery housing 20a: Outer surface of the closed section T1: 1st electrode terminal 21: Beading Section 22: Crimping Department 30: Current collector (first current collector) H2: Current collector hole 31: Support part 32: Tab joint H3: Liquid injection hole 33: Housing joint 33a: Contact part 33b: Connection part N: Notch area BW: Weld bead 40: Housing cover 41: Vent section G1: Seal gasket 50: Terminals T2: 2nd electrode terminal 60: Second current collector 70: Insulator

Claims

1. An electrode assembly comprising a first electrode and a second electrode, and a separation membrane interposed between them, which are wound around a winding axis to define a core and an outer surface, wherein the first electrode includes an active material portion coated with an active material layer along the winding direction, and a first plain portion not coated with an active material layer, and at least a portion of the first plain portion is used as an electrode tab, the electrode assembly A battery housing that accommodates the electrode assembly through an opening formed on one side, A current collector comprising a tab coupling portion that connects to the first blank portion, and a housing coupling portion that extends from the tab coupling portion and electrically connects to the inner surface of the battery housing, wherein the housing coupling portion is provided with at least one notch portion, Battery cells, including

2. The aforementioned battery housing is The battery cell according to claim 1, further comprising a beading portion formed at the end adjacent to the opening and recessed inward.

3. The housing joint portion is A contact portion that is coupled onto the beading portion of the battery housing, A connecting portion that connects the tab joint portion and the contact portion, The battery cell according to claim 2, including the battery cell described in claim 2.

4. The battery cell according to claim 3, wherein the notched portion is provided on the contact portion.

5. The battery cell according to claim 3, wherein a laser beam is irradiated onto the notch portion.

6. The battery cell according to claim 5, wherein the width of the notch portion is 10% to 90% of the width of the laser beam.

7. The battery cell according to claim 1, wherein the notch portion extends in a direction perpendicular to the radial direction of the battery cell.

8. The battery cell according to claim 3, wherein a plurality of notches are provided within one of the contact portions.

9. The battery cell according to claim 1, wherein the notched portions are arranged at predetermined intervals in the radial direction of the battery cell.

10. The battery cell according to claim 5, wherein the notch portion is configured to be included in multiple locations within the width of the laser beam.

11. The battery cell according to claim 2, wherein the notch portion is located on the flat upper surface of the beading portion.

12. The battery cell according to claim 5, wherein a weld bead formed by irradiation with the laser beam is provided at the contact portion.

13. The battery cell according to claim 1, wherein the notch portion is formed by partially reducing the thickness of the housing joint portion by cutting out a predetermined portion of the housing joint portion.

14. The notch portion is located on the flat upper surface of the beading portion, The battery cell according to claim 12, wherein the center of the weld bead is located inward with respect to the center of the flat upper surface of the beading portion.

15. It includes a tab coupling portion that connects to a blank portion of the electrode assembly of the battery cell, and a housing coupling portion that extends from the tab coupling portion and electrically connects to the inner surface of the battery housing of the battery cell, A current collector wherein the housing coupling portion is provided with at least one notch portion, and a laser beam is irradiated onto the notch portion, and the width of the notch portion is 10% to 90% of the width of the laser beam.

16. A battery pack comprising at least one battery cell as described in any one of claims 1 to 14.

17. An automobile comprising at least one battery pack as described in claim 16.

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