Battery cells, battery packs, and vehicles including these battery packs.

Abstract

According to one designation of the invention, the battery cell comprises an electrode assembly formed by winding a first and second electrode around a winding axis with a separator positioned in the middle to define the core and outer surface, wherein the first electrode comprises an active material portion coated with active material along the winding direction and the first uncoated portion not coated with active material, at least part of the first uncoated portion used as an electrode ear, the battery case is configured to receive the electrode assembly through an opening formed on one side, the case cover is configured to cover the opening and has a central through-hole, and a recessed ball is configured to be inserted into that through-hole.

Description

Battery cells and battery packs and vehicles containing the same

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

[0002] This application claims priority to Korean Patent Application No. 10-2024-0040379, filed on March 25, 2024, and Korean Patent Application No. 10-2025-0015117, filed on February 6, 2025, the entire contents of which are disclosed in the specification and drawings of the aforementioned applications are incorporated herein by reference.

[0003] Secondary batteries, which boast high electrical properties such as high energy density and high applicability across a wide range of product categories, are widely used not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs) powered by electrical power sources. These batteries are attracting attention as a new energy source for environmental friendliness and energy efficiency, not only because they can dramatically reduce fossil fuel use, but also because they produce no byproducts from energy use.

[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 these unit secondary battery cells, i.e., unit battery cells, is approximately 2.5 V to 4.5 V. Therefore, when a higher output voltage is required, multiple battery cells are connected in series to form a battery pack. Furthermore, depending on the charge / discharge capacity required for the battery pack, a number of battery cells are connected in parallel to form a battery pack. Therefore, the number of battery cells included in the battery pack can be set in various ways depending on the required output voltage and / or charge / discharge capacity.

[0005] Meanwhile, battery cells having a beading-clamping structure have existed in the past, and to implement such a structure, processes such as beading, crimping, and sizing were performed. Meanwhile, battery cells including such a beading-clamping structure had the problem of an increase in dead space within the battery in the winding axis direction, resulting in a decrease in energy density.

[0006] Accordingly, the present invention aims to increase energy density by excluding the beading crimping structure in a battery cell.

[0007] In addition, another object of the present invention is to prevent the occurrence of pores when welding a housing cover and a negative ball.

[0008] Furthermore, another object of the present invention is to prevent cracks from forming in the welding area of ​​the housing cover and the negative ball.

[0009] In addition, another object of the present invention is to improve the sealing properties of the contact area between the housing cover and the engraved ball.

[0010] However, the technical problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0011] According to one embodiment of the present invention for solving the above-described problem, a battery cell comprises an electrode assembly in which a core and an outer circumferential surface are defined by winding a first electrode, a second electrode, and a separator interposed therebetween around a winding axis, wherein the first electrode includes an active material portion coated with an active material layer along a winding direction, and a first uncoated portion not coated with an active material layer, wherein at least a portion of the first uncoated portion is used as an electrode tab in itself; a battery housing that accommodates the electrode assembly through an opening formed on one side; a housing cover that covers the opening and has a through hole in the center; and an engraved ball configured to be inserted into the through hole.

[0012] In one aspect of the present invention, the side of the battery housing may have a cylindrical shape with a constant radius.

[0013] In another aspect of the present invention, the housing cover may have a plate shape and be configured to be coupled to an opening of the battery housing.

[0014] In another aspect of the present invention, a battery cell characterized in that the diameter of the through hole is smaller than the diameter of the winding center hole of the electrode assembly.

[0015] In another aspect of the present invention, a battery cell characterized in that the diameter of the engraved ball is smaller than the diameter of the winding center hole of the electrode assembly.

[0016] In one aspect of the present invention, the engraved ball may have a groove on its periphery.

[0017] Preferably, the edge area of ​​the through hole of the housing cover can be fitted into the groove.

[0018] In another aspect of the present invention, the groove may be provided in an area facing outward in the axial direction of the battery cell based on the center of the negative ball.

[0019] In another aspect of the present invention, the volume of the negative ball located on the outside of the battery cell based on the groove may be configured to be smaller than the volume of the negative ball located on the inside of the battery cell.

[0020] In one aspect of the present invention, the angle of engagement between the housing cover and the engraved ball may be configured to exceed 90 degrees.

[0021] In another aspect of the present invention, a welding bead may be formed by welding at the contact point between the housing cover and the engraved ball.

[0022] In another aspect of the present invention, the welding bead can be formed to the inner surface of the housing cover.

[0023] Meanwhile, the present invention may include a method for manufacturing a battery cell, comprising: inserting an electrode assembly through an opening of a battery housing; covering the opening of the battery housing with a housing cover; and inserting an engraved ball having a groove around its periphery into a through hole provided in the housing cover.

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

[0025] In addition, the present invention provides a vehicle including at least one battery pack according to the above-described embodiment.

[0026] According to the present invention, energy density can be increased by excluding the beading crimping structure from the battery cell.

[0027] In addition, according to the present invention, it is possible to prevent the occurrence of pores when welding the housing cover and the negative ball.

[0028] Furthermore, according to the present invention, cracks can be prevented from forming in the welding area of ​​the housing cover and the negative ball.

[0029] In addition, the present invention can improve the sealing properties of the contact area between the housing cover and the negative ball.

[0030] However, the effects that can be obtained through the present invention are not limited to the effects described above, and other technical effects that are not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

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

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

[0033] Figure 2 is an exploded perspective view of Figure 1.

[0034] Figure 3 is a cross-sectional view of the battery cell of Figure 1.

[0035] Fig. 4 is a drawing for explaining the process of combining a negative ball and a housing cover according to a comparative example of the present invention.

[0036] FIG. 5 is a drawing for explaining the shape of an engraved ball according to one embodiment of the present invention.

[0037] FIG. 6 is a drawing for explaining a state before an engraved ball according to one embodiment of the present invention is coupled to a housing cover.

[0038] FIG. 7 is a drawing for explaining a process in which an engraved ball according to one embodiment of the present invention is inserted into a housing cover.

[0039] FIG. 8 is a drawing for explaining the joining angle between the engraved ball and the housing cover according to one embodiment of the present invention.

[0040] FIG. 9 is a drawing for explaining a process of laser welding in which a negative ball and a housing cover are combined according to one embodiment of the present invention.

[0041] FIG. 10 is a drawing for detailing the contact area between the engraved ball and the housing cover according to one embodiment of the present invention.

[0042] FIG. 11 is a drawing for explaining a battery pack including the battery module of FIG. 1.

[0043] FIG. 12 is a drawing for explaining a vehicle including the battery pack of FIG. 11.

[0044] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, it should be noted that the terms and words used in this specification and claims should not be interpreted as limited to their typical or dictionary meanings, and should be interpreted with meanings and concepts that conform to the technical spirit of the present invention based on the principle that the inventor can appropriately define the concept of the term to best explain his or her own invention. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are only some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention. Therefore, it should be understood that various equivalents and modified examples may exist as of the time of this application.

[0045] Additionally, to facilitate understanding of the invention, the attached drawings are not drawn to scale and some components may have exaggerated dimensions. Furthermore, identical components may be assigned the same reference numbers in different embodiments.

[0046] The statement that two compared objects are identical means "substantially identical." Therefore, "substantially identical" may include deviations considered low in the art, such as deviations of less than 5%. Furthermore, uniformity of a parameter over a given region may also mean uniformity on average.

[0047] Although terms like "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless otherwise specified, a "first" component may also be a "second" component.

[0048] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0049] Any configuration being placed "on (or below)" a component or "on (or below)" a component may mean not only that any configuration is placed in contact with the upper surface (or lower surface) of said component, but also that other configurations may intervene between said component and any configuration placed on (or below) said component.

[0050] Additionally, when it is described that a component is "connected," "coupled," or "connected" to another component, it should be understood that the components may be directly connected or connected to one another, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "connected" through another component.

[0051] Throughout the specification, when we refer to "A and / or B", this means A, B, or A and B, unless otherwise stated, and when we refer to "C to D", this means C or more and D or less, unless otherwise stated.

[0052] For convenience of explanation, in this specification, the direction along the longitudinal direction of the winding axis of the electrode assembly (10) wound in the form of a jelly roll is referred to as the axial direction. In addition, the direction surrounding the winding axis is referred to as the circumferential direction or the peripheral direction. In addition, the direction approaching or away from the winding axis is referred to as the radial direction. Among these, the direction approaching the winding axis is particularly referred to as the centripetal direction, and the direction away from the winding axis is referred to as the centrifugal direction.

[0053]

[0054] Fig. 1 is a drawing for explaining a battery cell (1) according to one embodiment of the present invention, and Fig. 2 is an exploded perspective view of Fig. 1. Fig. 3 is a cross-sectional view of the battery cell (1) of Fig. 1.

[0055] Referring to FIGS. 1 to 3, a battery cell (1) according to one embodiment of the present invention includes an electrode assembly (10), a battery housing (20), a housing cover (30), and an engraved ball (40). The battery cell (1) may further include a current collector (50). The present invention is not limited by the shape of the battery and can be applied to batteries of other shapes.

[0056] Referring to FIG. 3, the electrode assembly (10) includes a first non-coated portion (11) and a second non-coated portion (12). More specifically, the electrode assembly (10) has a structure in which the first electrode and the second electrode and the separator interposed therebetween are wound around a winding axis with a separator interposed therebetween, thereby defining a core and an outer circumferential surface. 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 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, without limitation, a winding structure well known in the art.

[0057] Referring to FIG. 3, the first electrode includes a first electrode current collector and a first electrode active material applied on one or both surfaces of the first electrode current collector. At one end of the first electrode in the width direction (parallel to the height direction of the battery cell (1) illustrated in FIG. 1), there is a non-coated portion on which the first electrode active material is not applied. That is, the first electrode includes a non-coated portion that is not coated with an active material at a long end along the winding direction and is exposed to the outside of the separator. The non-coated portion that functions as a first electrode tab is hereinafter referred to as a first non-coated portion (11). The first non-coated portion (11) is provided above the height direction (parallel to the height direction of the battery cell (1) illustrated in FIG. 1) of the electrode assembly (10) accommodated in the battery housing (20). That is, the first electrode includes a first non-conductive portion (11) that is not coated with an active material layer on a long end and is exposed to the outside of the separator, and at least a portion of the first non-conductive portion (11) is used as an electrode tab in itself. The first non-conductive portion (11) may be, for example, a negative electrode tab.

[0058] Referring to FIG. 3, the second electrode includes a second electrode current collector and a second electrode active material applied on one or both surfaces 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) illustrated in FIG. 1), there is a non-coated portion on which the second electrode active material is not applied. That is, the second electrode includes a non-coated portion on a long side along the winding direction that is not coated with an active material and is exposed to the outside of the separator. The non-coated portion that functions as a second electrode tab is hereinafter referred to as a second non-coated portion (12). The second non-coated portion (12) is provided at a lower portion in the height direction of the electrode assembly (10) accommodated in the battery housing (20). That is, the second electrode includes a second non-coated portion (12) on a 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 non-coated portion (12) is used as an electrode tab in and of itself. The above second non-conductive part (12) may be, for example, a positive electrode tab.

[0059] Meanwhile, 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 known in the art.

[0060]

[0061] Referring to FIGS. 1 to 3, the battery housing (20) may be configured as a roughly cylindrical receiver having an opening formed on one side. The battery housing (20) may include a conductive metal material. The side surface of the battery housing (20) and the lower surface located opposite the opening may be formed integrally. That is, the battery housing (20) may have an open upper portion in the height direction and a closed lower portion. The lower surface of the battery housing (20) may have a roughly flat shape. The battery housing (20) may accommodate an electrode assembly (10) through the opening formed on one side in the height direction. The battery housing (20) may also accommodate an electrolyte through the opening.

[0062] The side surface of the battery housing (20) may be configured to have a cylindrical shape with a constant radius. Preferably, the entire area of ​​the side surface of the battery housing (20) may be configured to have a cylindrical shape with a constant radius. For example, in some cases, a conventional battery housing (20) further includes a beading portion formed at an end adjacent to an opening portion and a crimping portion formed on the beading portion. However, the battery housing (20) of the present invention does not have a beading crimping structure formed on the side surface. That is, the side surface of the battery housing (20) of the present invention is not recessed inward. That is, the battery housing (20) of the present invention is configured to have a constant radius in the entire area of ​​the side surface.

[0063] According to this structure, by excluding the beading crimping structure from the cylindrical battery cell (1), the occurrence of various process errors that may occur due to the beading crimping structure can be prevented. In addition, process simplification can be achieved by omitting the beading, crimping, and sizing processes. Furthermore, in the case of having the beading crimping structure, the phenomenon of dead space within the battery increasing in the winding axis direction of the electrode assembly (10) and thus lowering the energy density can be prevented. That is, according to the above structure of the present invention, the energy density of the battery cell (1) can be improved.

[0064] In another aspect of the present invention, the battery housing (20) can be electrically connected to the first non-conductive portion (11). Accordingly, the battery housing (20) can assume the first polarity.

[0065]

[0066] Referring back to FIGS. 1 to 3, the housing cover (30) may be configured to cover the opening formed on one side of the battery housing (20). The housing cover (30) may be configured to have, for example, an approximately plate shape. The housing cover (30) may be coupled to the opening of the battery housing (20). More specifically, the housing cover (30) may be coupled to the battery housing (20) at the upper end of the battery housing (20). Preferably, the housing cover (30) may be fixed by coupling to the battery housing (20) at the upper end of the battery housing (20). For example, referring to FIGS. 1 and 3, the housing cover (30) may be seated on the upper edge of the opening of the battery housing (20). At this time, the contact point of the upper edge of the battery housing (20) and the housing cover (30) may be coupled. For example, the joining point between the upper edge of the battery housing (20) and the housing cover (30) may be joined by welding. It goes without saying that the battery housing (20) and the housing cover (30) may be joined by a joining form other than welding, and the joining form is not limited thereto. By joining the battery housing (20) and the housing cover (30), the sealing of the battery cell (1) can be ensured.

[0067] Meanwhile, the housing cover (30) may be made of a metal material. Accordingly, the housing cover (30) may have conductivity. For example, the housing cover (30) may include an aluminum material. Meanwhile, since the battery housing (20) is also made of a metal having conductivity, the housing cover (30) coupled with the battery housing (20) may also be configured to have the same polarity as the battery housing (20). For example, the housing cover (30) may be configured to have the first polarity.

[0068]

[0069] In another aspect of the present invention, the housing cover (30) may have a through hole (H) in at least a portion of the area. At this time, the through hole (H) may be blocked by a negative ball (40) to be described later. For example, the negative ball (40) may be pressed into the through hole (H). Consequently, by blocking the through hole (H) by the negative ball (40), the sealing property of the battery cell (1) may be ensured.

[0070] Meanwhile, the through hole (H) may be configured to discharge gases generated during the precharge process. That is, after a degas process in which all gases generated during the precharge process are discharged through the through hole (H), the negative ball (40) may be configured to be coupled onto the through hole (H). Accordingly, swelling of the battery cell (1) can be prevented.

[0071]

[0072] In another aspect of the present invention, the housing cover (30) may have a through hole (H) in the center. The through hole (H) may, for example, serve as an electrolyte injection hole. The center of the through hole (H) may coincide with the center of the winding center hole (H1) of the electrode assembly (10). That is, the through hole (H) of the housing cover (30) may be positioned above the winding center hole (H1) of the electrode assembly (10) in the winding axis direction. Preferably, the diameter of the through hole (H) may be configured to be smaller than the diameter of the winding center hole (H1) of the electrode assembly (10).

[0073] According to this structure, when the negative ball (40) is pressed into the through hole (H), the negative ball (40) moves downward. At this time, the negative ball (40) moved downward can be prevented from causing damage to the electrode assembly (10) or the current collector (50) coupled to the electrode assembly (10). That is, even if the negative ball (40) is pressed downward, the negative ball (40) does not affect the folded surface or electrode tab of the electrode assembly (10) because it enters the winding center hole (H1) of the electrode assembly (10).

[0074]

[0075] In the same spirit, the diameter of the engraved ball (40) may be configured to be smaller than the diameter of the winding center hole (H1) of the electrode assembly (10). It is preferable that the diameter of the engraved ball (40) is about 70% or less of the diameter of the winding center hole (H1) of the electrode assembly (10). It is preferable that the diameter of the engraved ball (40) is about 66% or less of the diameter of the winding center hole (H1) of the electrode assembly (10). For example, when the diameter of the winding center hole (H1) is about 6 mm, the diameter of the engraved ball (40) may be configured to be about 4 mm.

[0076] According to this structure, since the diameter of the negative ball (40) is smaller than the winding center hole (H1) of the electrode assembly (10), even if the negative ball (40) is pressed downward, the negative ball (40) is formed to enter the winding center hole (H1) of the electrode assembly (10), so it does not affect the folded surface or electrode tab of the electrode assembly (10).

[0077]

[0078] In another aspect of the present invention, referring to FIGS. 1 to 3, the engraved ball (40) may be configured to be inserted into the through hole (H).

[0079] For example, the engraved ball (40) may be configured to have a roughly spherical shape. Alternatively, as implemented in one embodiment of the present invention, it may be configured in a slightly flattened ball shape that is compressed upward and downward. By inserting the engraved ball (40) into the through hole (H) of the housing cover (30), the sealing of the battery cell (1) can be secured.

[0080] With this structure, the beading, crimping, and sizing processes can be omitted, thereby achieving process simplification. Furthermore, the beading and crimping structure can prevent the phenomenon of dead space within the battery increasing in the winding axis direction of the electrode assembly (10), thereby lowering the energy density. In other words, with the above-described structure of the present invention, the energy density of the battery cell (1) can be improved.

[0081]

[0082] Fig. 4 is a drawing for explaining the process of combining an engraved ball (40) and a housing cover (30) according to a comparative example of the present invention.

[0083] For example, the engraved ball (40) according to the comparative example of the present invention may be configured as a roughly spherical structure with a convex outer surface. When the engraved ball (40) having a roughly spherical shape is pressed into the through hole (H) of the housing cover (30) in this way, as shown in FIG. 4, the joining angle between the engraved ball (40) and the housing cover (30) becomes small due to excessive pressing. For example, when the engraved ball (40) according to the comparative example of the present invention is pressed into the housing cover (30), the joining angle may be configured as a roughly acute angle. When the joining angle between the engraved ball (40) and the housing cover (30) becomes acute in this way, when the laser beam (L) is irradiated to the joining point of the housing cover (30) and the engraved ball (40), welding energy cannot be sufficiently transmitted to the exact point where the engraved ball (40) and the housing cover (30) meet. For example, referring to FIG. 4, when the point where the edge of the laser beam (L) and the engraved ball (40) meet is P1, the point where the edge of the laser beam (L) and the housing cover (30) meet is P2, and the intersection point where the engraved ball (40) and the housing cover (30) meet is P3, the laser beam (L) is irradiated to all areas encompassing P1, P2, and P3, but as the coupling angle becomes narrower, the most energy is transferred to points P1 and P2, which are the areas where the laser beam (L) first hits, and relatively less energy may be transferred to P3. Accordingly, the possibility of pores forming in the area where the engraved ball (40) and the housing cover (30) meet increases. More specifically, when the laser is concentratedly irradiated to points P1 and P2, the area near point P1 of the engraved ball (40) and the area near point P2 of the housing cover (30) melt and flow down to point P3. At this time, an air gap is formed at point P3, and the air located in the air gap meets the molten base material in the area near point P1 of the negative ball (40) and the molten base material in the area near point P2 of the housing cover (30).As a result, the resin hardens into a porous structure. Ultimately, cracks develop due to the pores in this porous structure, reducing sealing performance.

[0084]

[0085] On the other hand, the above problem can be solved by using an engraved ball (40) according to one embodiment of the present invention. Fig. 5 is a drawing for explaining the shape of an engraved ball (40) according to one embodiment of the present invention.

[0086] Referring to Fig. 5, the engraved ball (40) may have a groove (G) on its periphery. The groove (G) may be a groove recessed toward the inside of the engraved ball (40). That is, the engraved ball (40) may be configured to have a shape in which at least a portion of the periphery is recessed inward. The shape of the groove (G) recessed inward is not particularly limited. For example, as shown in Fig. 5, the groove (G) may be configured to have a right-angled cross-section.

[0087] In one aspect of the present invention, the edge area of ​​the through hole (H) of the housing cover (30) may be configured to fit into the groove (G). Preferably, the edge area of ​​the through hole (H) of the housing cover (30) may be configured to be forcibly fitted into the groove (G).

[0088] That is, the groove (G) can be fitted into the through hole (H) of the housing cover (30). For example, both the engraved ball (40) and the housing cover (30) can be made of a metal having hardness, but due to the elasticity of the housing cover (30) having a relatively thin thickness, when the engraved ball (40) is pressed into the housing cover (30), the edge area of ​​the through hole (H) of the housing cover (30) can be fitted into the groove (G) provided in the engraved ball (40).

[0089] Preferably, the cross-sectional shape of the groove (G) may be configured to match the cross-sectional shape of the through hole (H) of the housing cover (30). For example, referring to FIG. 3, the cross-section of the group of engraved balls (40) may be configured to have a right-angled shape. At this time, the cross-section of the through hole (H) may also be configured to have a right-angled shape matching therewith. In this case, the sealing between the housing cover (30) and the engraved balls (40) may be further improved.

[0090] According to the above structure, since the edge area of ​​the through hole (H) of the housing cover (30) is structured to fit into the groove (G), there is no play between the housing cover (30) and the negative ball (40). That is, the risk of an air gap occurring between the housing cover (30) and the negative ball (40) is reduced. Accordingly, the phenomenon of the molten base material during welding meeting the air gap and solidifying into a porous structure can be prevented. Ultimately, according to the configuration of the present invention, the occurrence of cracks due to pores at the welding location can be prevented. Accordingly, the sealing performance of the battery cell (1) can be improved.

[0091] In addition, according to the above configuration, the joining angle between the housing cover (30) and the negative ball (40) can be secured at a predetermined angle or higher. Accordingly, the ease of welding can be improved. More specifically, due to the wide joining angle between the housing cover (30) and the negative ball (40), the formation of pores in the welding area is minimized, thereby preventing the formation of cracks in the welding area during laser welding. Accordingly, the sealing between the housing cover (30) and the negative ball (40) can be secured. In addition, the joining strength between the housing cover (30) and the negative ball (40) can be secured at a predetermined level or higher.

[0092]

[0093] Referring again to FIG. 5, the groove (G) may be provided in an area facing outward in the axial direction of the battery cell (1) based on the center of the negative ball (40). For example, the dotted line illustrated in FIG. 5 means an imaginary line penetrating the center of the negative ball (40). That is, the dotted line may be viewed as the center line of the negative ball (40).

[0094] Based on the center line, the engraved ball (40) may include a first region (41) located in an area facing outward in the axial direction of the battery cell (1); and a second region (42) located in an area facing inward in the axial direction of the battery cell (1). In this case, the groove (G) may be provided on the first region (41).

[0095] Preferably, that is, based on the groove (G), the volume of the negative ball (40) located on the outside of the battery cell (1) can be configured to be smaller than the volume of the negative ball (40) located on the inside of the battery cell (1). That is, the volume of the first region (41) of the negative ball (40) can be configured to be smaller than the volume of the second region (42) of the negative ball (40).

[0096] According to this structure, when welding is performed between the engraved ball (40) and the housing cover (30), the laser beam (L) can more easily reach the contact area of ​​the groove (G) and the through hole (H). In other words, the laser beam (L) is irradiated in a form that directly touches the first region (41) of the engraved ball (40), and at this time, since the thickness of the first region (41) of the engraved ball (40) is smaller than the thickness of the second region (42), the irradiation distance from the first region (41) of the engraved ball (40) where the laser beam (L) is directly irradiated to the contact point of the groove (G) and the through hole (H) can be reduced. Accordingly, the welding performance at the contact point of the groove (G) and the through hole (H) can be improved.

[0097]

[0098] In another aspect of the present invention, the negative ball (40) may be configured to be conductive. That is, the negative ball (40) may include a metal. For example, the negative ball (40) may include an aluminum material. Accordingly, the negative ball (40) may have the same polarity as the housing cover (30) with which it is in direct contact. For example, the negative ball (40) may have a first polarity.

[0099]

[0100] In one aspect of the present invention, the housing cover (30) may have a plate shape in which a central region is recessed inward. For example, the central region including the through hole (H) of the housing cover (30) may be recessed to a predetermined depth toward the inside of the battery cell (1). For example, an area having a predetermined radius based on the center of the housing cover (30) may be recessed to a predetermined depth toward the inside of the battery cell (1).

[0101] According to the structure as described above, when the negative ball (40) is inserted into the housing cover (30), the negative ball (40) protrudes upward from the housing cover (30) by the height of the first region (41). At this time, if the central region of the housing cover (30) is recessed toward the inside of the battery cell (1) by the height of the first region (41), even if the negative ball (40) protrudes upward from the housing cover (30) by the height of the first region (41), the negative ball (40) does not protrude outward from the upper surface of the battery cell (1). Accordingly, when the upper surface of the battery cell (1) is placed on the floor, it can be maintained horizontally.

[0102]

[0103] In another aspect of the present invention, the engraved ball (40) may be provided with a substantially flat surface (F) in an area facing the outside of the battery cell (1).

[0104] For example, referring to Fig. 5, the upper portion of the first region (41) of the engraved ball (40) may be provided with a flat portion (F) in which a certain region is configured to be flat. That is, the first region (41) may be configured to have a substantially flat shape.

[0105] According to this configuration, the force applied when the negative ball (40) is pressed in can be applied uniformly to the negative ball (40). In addition, according to the above structure, since the thickness of the first region (41) of the negative ball (40) becomes smaller, the irradiation distance from the first region (41) of the negative ball (40) where the laser beam (L) is directly irradiated to the contact point between the groove (G) and the through hole (H) can be reduced. Accordingly, the welding performance at the contact point between the groove (G) and the through hole (H) can be improved.

[0106]

[0107] FIG. 6 is a drawing for explaining a state before an engraved ball (40) according to one embodiment of the present invention is coupled to a housing cover (30), and FIG. 7 is a drawing for explaining a process in which an engraved ball (40) according to one embodiment of the present invention is inserted into a housing cover (30).

[0108] Referring to FIGS. 6 and 7, the diameter of the engraved ball (40) may be configured to be larger than the diameter of the through hole (H). That is, since the diameter of the through hole (H) of the housing cover (30) is smaller than the diameter of the engraved ball (40), as shown in FIG. 6, before the engraved ball (40) is pressed in, the engraved ball (40) is placed on the through hole of the housing cover (30).

[0109] According to the above configuration, since the diameter of the negative ball (40) is larger than the diameter of the through hole (H), once the negative ball (40) is pressed into the through hole (H) and is in a combined state, the probability of the negative ball (40) being detached from the through hole (H) becomes very low.

[0110]

[0111] Meanwhile, on the other hand, the diameter of the through hole (H) may be larger than or equal to the diameter of the groove (G). Therefore, when the engraved ball (40) is pressed in a direction toward the housing cover (30), the housing cover (30) in the area around the through hole (H) is slightly bent downward due to the elasticity of the housing cover (30), and then returns to its original flat state due to the elasticity of the housing cover (30), so that the groove (G) can be fitted into the through hole (H). That is, the edge area of ​​the through hole (H) of the housing cover (30) can be fitted into the groove (G). At this time, it is more preferable that the diameter of the groove (G) is configured to be the same as the diameter of the through hole (H).

[0112] According to the above configuration, since the diameter of the groove (G) and the diameter of the through hole (H) are configured to be the same, the existence of a minute gap between the groove (G) and the through hole (H) can be prevented. Accordingly, when the laser beam (L) is irradiated to the contact point between the groove (G) and the through hole (H), welding can be performed smoothly. In other words, welding performance can be improved.

[0113]

[0114] FIG. 8 is a drawing for explaining a joining angle between a negative ball (40) and a housing cover (30) according to one embodiment of the present invention, and FIG. 9 is a drawing for explaining a process in which laser welding is performed while the negative ball (40) and the housing cover (30) according to one embodiment of the present invention are joined.

[0115] Referring to FIGS. 8 and 9, the joining angle between the housing cover (30) and the engraved ball (40) may be configured to be greater than or equal to about 90 degrees. Conversely, referring to FIG. 4, the joining angle between the housing cover (30) and the engraved ball (40) according to the comparative example of the present invention is configured to be less than about 90 degrees. As described above, when the joining angle between the housing cover (30) and the engraved ball (40) is narrowed, the most energy may be transferred to points P1 and P2, which are areas where the laser beam (L) first hits, and relatively less energy may be transferred to P3. Accordingly, the possibility of pores forming in the area where the engraved ball (40) and the housing cover (30) meet increases. Ultimately, cracks may be generated due to these pores, and the sealing performance may deteriorate.

[0116] Conversely, according to the shape of the negative ball (40) according to one embodiment of the present invention, the joining angle formed by the housing cover (30) and the negative ball (40) may be greater than or equal to about 90 degrees. Preferably, according to the shape of the negative ball (40) according to one embodiment of the present invention, the joining angle formed by the housing cover (30) and the negative ball (40) may be greater than or equal to about 90 degrees, i.e., an obtuse angle.

[0117] More specifically, the above-mentioned joining angle refers to the angle between the tangent of the negative ball (40) at the intersection where the negative ball (40) and the housing cover (30) meet and the housing cover (30). That is, the above-mentioned joining angle refers to the angle between the tangent of the negative ball (40) at the point where the first region (41) starts based on the groove (G) and the housing cover (30). In other words, according to the negative ball (40) structure of the present invention, the slope formed by the tangent of the negative ball (40) at the point where the first region (41) starts based on the groove (G) is configured to be gentle. That is, the tangent of the negative ball (40) at the point where the first region (41) starts based on the groove (G) can be tilted toward the winding center of the electrode assembly (10). Preferably, the angle of engagement between the housing cover (30) and the engraved ball (40) can be configured to be an obtuse angle.

[0118] According to this structure, it is possible to prevent energy from being concentrated and transmitted to points P1 and P2, which are the areas where the laser beam (L) first hits. That is, since the angle formed by the housing cover (30) and the negative ball (40) is approximately 90 degrees or more, a sufficient amount of energy can also be transmitted to point P3, which is the intersection point where the negative ball (40) and the housing cover (30) meet. Accordingly, the possibility of pores forming in the area where the negative ball (40) and the housing cover (30) meet is reduced.

[0119] More specifically, according to the shape of the engraved ball (40) according to one embodiment of the present invention, since the joining angle between the housing cover (30) and the engraved ball (40) exceeds about 90 degrees, an air gap is not formed near the point P3. That is, according to the structure of the present invention, since the joining angle between the housing cover (30) and the engraved ball (40) becomes an obtuse angle, the phenomenon of the laser being concentratedly irradiated to the points P1 and P2 can be prevented. Accordingly, the phenomenon of the area near the point P1 of the engraved ball (40) and the area near the point P2 of the housing cover (30) melting and flowing down to the point P3 is prevented. Therefore, the phenomenon of the base material melted by welding solidifying into a porous structure can be effectively prevented. Ultimately, according to the present invention, the occurrence of cracks due to such pores can be prevented. Accordingly, the sealing performance of the battery cell (1) can be improved.

[0120]

[0121] In one aspect of the present invention, a welding bead may be formed by welding at the contact point between the housing cover (30) and the engraved ball (40).

[0122] For example, referring to FIG. 9, a laser beam (L) can be irradiated centered on P3, which is the intersection point where the negative ball (40) and the housing cover (30) meet. At this time, since the laser beam (L) is configured to have a cross-section with a predetermined area, the laser beam (L) can be irradiated not only to P3 but also to the surrounding area of ​​P3. That is, the laser beam (L) can be irradiated from the point (P1) where the edge point of the laser beam (L) and the negative ball (40) meet to the point (P2) where the edge point of the laser beam (L) and the housing cover (30) meet. At this time, since the joining angle formed by the housing cover (30) and the negative ball (40) as described above is approximately 90 degrees or more, a sufficient amount of energy can be transmitted to P3, which is the intersection point where the negative ball (40) and the housing cover (30) meet. Accordingly, a welding bead can be formed in the area including P1, P2, and P3.

[0123] If the negative ball (40) is pressed into the through hole (H) of the housing cover (30) and welding is not performed, the sealing strength at the contact point between the negative ball (40) and the housing cover (30) may be relatively low. However, with the configuration as described above, the bonding strength at the joining point between the negative ball (40) and the housing cover (30) may be improved. In addition, the sealing performance at the joining point between the negative ball (40) and the housing cover (30) may be improved.

[0124]

[0125] FIG. 10 is a drawing for explaining in detail the contact area between the engraved ball (40) and the housing cover (30) according to one embodiment of the present invention.

[0126] In one aspect of the present invention, the area where the housing cover (30) is coupled to the negative ball (40) can be defined in detail. For example, referring to FIG. 10, on the outer surface of the housing cover (30), the area where the housing cover (30) begins to contact the negative ball (40) can be defined as area A. Meanwhile, on the outer surface of the housing cover (30), the area where the housing cover (30) is inserted into the groove (G) of the negative ball (40) can be defined as area B. Next, the area where the inner surface of the through hole (H) of the housing cover (30) and the innermost point of the groove (G) of the negative ball (40) meet can be defined as area C. On the inner surface of the housing cover (30), the area where the housing cover (30) is inserted into the groove (G) of the negative ball (40) can be defined as area D. Finally, on the inner surface of the housing cover (30), the area where the housing cover (30) begins to contact the engraved ball (40) can be defined as area E.

[0127] Here, the laser beam (L) can be directly irradiated to area A. At this time, if the size of the cross-section of the laser beam (L) is adjusted, the influence of the laser beam (L) can also reach area B. In some cases, if the power and irradiation depth of the laser beam (L) are adjusted, the influence of the laser beam (L) can also reach areas C, D, and E. Preferably, by adjusting the power and irradiation depth of the laser beam (L), the laser beam (L) can be configured to be irradiated to all areas A to E. That is, according to the above configuration, 1st to 5th welding can be performed for each of areas A to E.

[0128] With this configuration, the welding bead can be formed up to the inner surface of the housing cover (30). That is, even if the laser beam (L) is irradiated from the outside of the battery cell (1), the laser beam (L) can affect all areas of A to E, so that welding joint with the engraved ball (40) is possible even on the inner surface of the housing cover (30). That is, depending on the welding depth and angle, 1 to 5 sealings are possible in all areas of A to E. Therefore, with the above configuration, the bonding strength at the joining point of the engraved ball (40) and the housing cover (30) can be improved. In addition, the sealing performance at the joining point of the engraved ball (40) and the housing cover (30) can be improved. Meanwhile, for the convenience of explanation, the area where the housing cover (30) is joined to the engraved ball (40) is subdivided into 5 sections of A to E, but it is not limited thereto and can be subdivided into more sections.

[0129]

[0130] Referring again to FIGS. 2 and 3, the battery cell (1) may further include a current collector (50) coupled to the first non-conductive portion (11) and electrically coupled to the inner surface of the housing cover (30).

[0131] According to one embodiment of the present invention, a current collector (50) is accommodated inside a battery housing (20), is electrically connected to an electrode assembly (10), and is also electrically connected to the battery housing (20). That is, the current collector (50) electrically connects the electrode assembly (10) and the battery housing (20). That is, the current collector (50) may include a metal having conductivity.

[0132] The current collector (50) may be configured in a roughly plate shape. At this time, the lower surface of the plate may be electrically coupled to the first non-conductive portion (11). Meanwhile, the upper surface of the plate may be electrically coupled to the housing cover (30). Alternatively, the upper surface of the plate may not be in direct contact with the housing cover (30), but may be electrically connected in an indirect manner through a structure such as a lead tab. That is, the current collector (50) may be configured to electrically connect the housing cover (30) and the first non-conductive portion (11). The connection between the current collector (50) and the first non-conductive portion (11) and / or the housing cover (30) may be, for example, a welding connection.

[0133] The above current collector (50) may be provided with a current collector hole formed at a position corresponding to a winding center hole (H1) formed at approximately the center of the electrode assembly (10). The winding center hole (H1) and the current collector hole, which are connected to each other, may function as a passage for insertion of a welding rod for welding between a terminal and a second current collector or welding between a terminal and a lead tab (not shown) or for irradiation of a laser beam.

[0134] Meanwhile, the current collector (50) may be provided with at least one injection hole. The injection holes may be provided radially, for example, based on the hole of the current collector (50). For example, the injection holes may be provided in multiple numbers. In this case, the injection property may be improved due to the injection holes.

[0135]

[0136] A battery cell (1) having a configuration as described above can be manufactured by the steps of: inserting an electrode assembly (10) through an opening of a battery housing (20); covering the opening of the battery housing (20) with a housing cover (30); and inserting an engraved ball (40) having a groove (G) on its periphery into a through hole (H) provided in the housing cover (30).

[0137] According to this manufacturing method, the gas generated during the pre-charge process can be smoothly discharged. That is, after the degas process in which all gases generated during the pre-charge process are discharged through the through-hole (H), the engraved ball (40) can be bonded onto the through-hole (H). Accordingly, the swelling phenomenon of the battery cell (1) can be prevented. In addition, according to the above manufacturing method, the electrolyte can be smoothly injected through the through-hole (H) provided in the housing cover (30). Furthermore, according to the above configuration, the sealing between the housing cover (30) and the engraved ball (40) can be secured. In addition, the bonding strength between the housing cover (30) and the engraved ball (40) can be secured to a predetermined level or higher.

[0138]

[0139] FIG. 11 is a drawing for explaining a battery pack including a battery cell (1) according to one embodiment of the present invention.

[0140] Referring to FIG. 11, a battery pack (3) according to an embodiment of the present invention includes a battery assembly in which a plurality of battery cells (1) according to an embodiment of the present invention are electrically connected, and a pack housing (2) accommodating the battery cells. In the drawing of the present invention, components such as a bus bar, a cooling unit, and a power terminal for electrical connection are omitted for convenience of illustration. In addition, the battery pack (3) may further include various components, such as components of a battery pack (3) known at the time of filing of the present invention, such as a BMS, a pack case, a relay, and a current sensor.

[0141]

[0142] Fig. 12 is a drawing for explaining a vehicle including the battery pack (3) of Fig. 11.

[0143] Referring to FIG. 12, a vehicle (5) according to an embodiment of the present invention may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle, and includes a battery pack (3) according to an embodiment of the present invention. The vehicle (5) includes a four-wheeled vehicle and a two-wheeled vehicle. The vehicle (5) operates by receiving power from the battery pack (3) according to an embodiment of the present invention. In addition, the vehicle (5) according to the present invention may further include various other components included in the vehicle in addition to the battery cell (1) or the battery pack (3). For example, the vehicle (5) according to the present invention may further include a body, a motor, a control device such as an ECU (electronic control unit), etc. in addition to the battery cell (1) according to the present invention.

[0144]

[0145] Meanwhile, although terms indicating directions such as up and down are used in this specification, it is obvious to those skilled in the art that these terms are only for convenience of explanation and may vary depending on the location of the target object or the location of the observer.

[0146] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0147]

[0148] [Explanation of symbols]

[0149] 5 cars

[0150] 3 battery packs

[0151] 2-pack housing

[0152] 1 battery cell

[0153] 10 electrode assembly

[0154] 11th 1st Military Department

[0155] 12. Second Military Department

[0156] H1 winding center hole

[0157] 20 Battery Housing

[0158] 30 Housing Cover

[0159] H penetration

[0160] 40 engraved balls

[0161] G groove

[0162] 41 Area 1

[0163] 42 Area 2

[0164] F flat area

[0165] D penetration depth

[0166] 50 whole house

[0167] L laser beam

Claims

1. An electrode assembly in which a core and an outer surface are defined by winding a first electrode, a second electrode, and a separator interposed therebetween around a winding axis, wherein the first electrode includes an active material portion coated with an active material layer along a winding direction, and a first uncoated portion not coated with an active material layer, and at least a portion of the first uncoated portion is used as an electrode tab in itself; A battery housing that accommodates the electrode assembly through an opening formed on one side; A housing cover covering the above opening and having a through hole in the center; and A concave ball configured to be inserted into the above-mentioned through hole Battery cells containing .

2. In paragraph 1, A battery cell characterized in that the side surface of the battery housing has a cylindrical shape with a constant radius.

3. In paragraph 1, A battery cell characterized in that the housing cover has a plate shape and is configured to be coupled to an opening of the battery housing.

4. In paragraph 1, A battery cell characterized in that the diameter of the above through hole is smaller than the diameter of the winding center hole of the above electrode assembly.

5. In paragraph 1, A battery cell characterized in that the diameter of the engraved ball is smaller than the diameter of the winding center hole of the electrode assembly.

6. In paragraph 1, A battery cell characterized in that the above-mentioned negative ball has a groove on its periphery.

7. In paragraph 6, A battery cell characterized in that the edge area of ​​the through hole of the housing cover is fitted into the groove.

8. In paragraph 6, A battery cell characterized in that the groove is provided in an area facing outward in the axial direction of the battery cell based on the center of the engraved ball.

9. In paragraph 6, A battery cell characterized in that, based on the groove, the volume of the negative ball located on the outside of the battery cell is smaller than the volume of the negative ball located on the inside of the battery cell.

10. In paragraph 1, A battery cell characterized in that the joining angle formed by the housing cover and the engraved ball exceeds 90 degrees.

11. In paragraph 1, A battery cell characterized in that a welding bead is formed by welding at the contact point between the housing cover and the engraved ball.

12. In paragraph 11, A battery cell characterized in that the welding bead is formed to the inner surface of the housing cover.

13. A method for manufacturing a battery cell, A step of inserting an electrode assembly through an opening in a battery housing; A step of covering the opening of the battery housing with a housing cover; and A method for manufacturing a battery cell, comprising the step of inserting an engraved ball having a groove on its periphery into a through hole provided in the housing cover.

14. A battery pack comprising at least one battery cell as described in any one of claims 1 to 12.

15. A vehicle characterized by including at least one battery pack as described in paragraph 14.

Images