SEALING GASKET, BATTERY CELL, BATTERY PACK, AND VEHICLE INCLUDING THEM

Abstract

A sealing gasket capable of improving the sealing force and electrolyte leakage prevention performance of a battery cell and effectively preventing electrolyte leakage caused by deformation due to the folding process, and a battery cell incorporating such gasket is proposed. The battery cell according to one design of the invention comprises: a battery housing constructed to contain the secondary battery electrode assembly and having an opening on one side; a battery cover fitted to the battery housing to cover the opening of the battery housing; and a sealing gasket surrounding the battery cover to seal the space between the battery cover and the battery housing. The sealing gasket and the upper end of the battery housing are constructed to be bent by a folding process to wrap around the rim of the battery cover. The sealing gasket has a groove in the part corresponding to the angle of the upper surface of the battery cover rim.

Description

Sealing gasket, battery cell, battery pack, and automobile including the same

[0001] The present invention relates to a sealing gasket, a battery cell, a battery pack, and an automobile including the same.

[0002] Secondary batteries are attracting attention as an energy source for improving eco-friendliness and energy efficiency because they have high energy density and the advantage of being able to drastically reduce the use of fossil fuels, as well as the advantage of not generating by-products from energy use. Due to these advantages, secondary batteries are widely applied not only to portable devices but also to electric vehicles (EVs) or hybrid electric vehicles (HEVs) driven by electric power sources.

[0003] When a high output voltage is required, the output voltage can be supplied by a battery pack formed by connecting multiple unit secondary battery cells, i.e., battery cells, in series. Additionally, a battery pack can be configured by connecting multiple battery cells in parallel according to the required charge / discharge capacity of the battery pack. The number of battery cells included in the battery pack can be varied depending on the required output voltage and / or charge / discharge capacity.

[0004] A battery cell comprises an electrode assembly including a positive electrode, a negative electrode, and a separator, and a battery housing that accommodates the electrode assembly. An electrolyte is filled into the battery housing to facilitate chemical reactions at the electrodes through the movement of ions. To prevent leakage of the electrolyte injected into the battery housing, a sealing gasket is provided in the battery housing of the battery cell for sealing.

[0005] The sealing gasket is bent together with the top of the battery housing through a crimping process to seal the gap between the rim of the battery cell's cap and the battery housing. As these crimping and sizing processes are performed, deformation occurs in the sealing gasket; if this deformation creates a minute gap between the battery cap and the sealing gasket, there is a risk of electrolyte leakage from the battery housing.

[0006] Accordingly, a technology is required to enhance the sealing force of the sealing gasket regardless of the crimping or sizing process, so as to more reliably prevent leakage of the electrolyte filled within the battery housing. The background technology described above is intended to explain the background in which the present invention was derived and does not imply that it is technology known prior to the filing of the present invention.

[0007] One objective of the present invention is to provide a sealing gasket capable of enhancing the sealing force and electrolyte leakage prevention performance of a battery cell and effectively preventing electrolyte leakage caused by deformation due to a crimping process, and a battery cell including the same.

[0008] In addition, the present invention is intended to enhance the sealing performance of a battery cell by maintaining alignment between the battery cap and the sealing gasket during the crimping process, ensuring that the crimping process proceeds in the correct position, and preventing lifting of the sealing gasket and abnormal sealing.

[0009] The technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems will be clearly understood by a person skilled in the art from the description of the invention below.

[0010] A battery cell according to one embodiment of the present invention comprises: a battery housing configured to accommodate an electrode assembly of a secondary battery and having an opening on one side; a battery cap coupled to the battery housing to cover the opening of the battery housing; and a sealing gasket that surrounds the battery cap to seal the space between the battery cap and the battery housing.

[0011] The sealing gasket and the upper portion of the battery housing are bent by a crimping process to wrap around the edge of the battery cap.

[0012] The sealing gasket has a groove portion corresponding to the upper edge corner of the battery cap.

[0013] The above groove may be formed to be inclined upward in a direction away from the edge of the battery cap.

[0014] One end of the groove located on the inner surface of the sealing gasket may be configured to contact the upper edge corner of the rim of the battery cap.

[0015] The above groove may be formed at an angle of 30° to 60° relative to a horizontal plane parallel to the upper surface of the battery cap.

[0016] The above groove may be formed such that the depth from one end to the other end is 30% to 70% of the thickness of the sealing gasket defined based on the direction of the groove.

[0017] The sealing gasket may have a plurality of grooves in a portion corresponding to the upper edge corner of the rim of the battery cap. The plurality of grooves may include a first groove and a second groove formed on the upper portion of the first groove.

[0018] Based on the state prior to the crimping process, the first groove may be formed at a first angle with respect to the horizontal direction, and the second groove may be formed at a second angle with respect to the horizontal direction that is greater than the first angle.

[0019] The width of the groove may vary along the depth direction of the groove based on the state before the crimping process. The width of the groove may decrease linearly or non-linearly as the depth increases from the inner surface of the sealing gasket.

[0020] The sealing gasket may be provided with a sealing reinforcing projection formed to protrude along the inner circumference of the sealing gasket at the lower part of the groove.

[0021] The above sealing reinforcement protrusion may be formed at a position in contact with a side perpendicular to the upper and lower edges of the battery cap.

[0022] The battery cap may be provided with a sealing reinforcement groove formed as an indentation on the side of the battery cap to be shaped-fitted to the sealing reinforcement projection.

[0023] The vertical size of the sealing reinforcement protrusion can be formed to be 10% to 30% of the thickness of the edge portion of the battery cap.

[0024] The sealing gasket may be provided with a plurality of sealing reinforcing protrusions along the inner circumference of the sealing gasket. The plurality of sealing reinforcing protrusions may include a first sealing reinforcing protrusion and a second sealing reinforcing protrusion formed on the upper portion of the first sealing reinforcing protrusion.

[0025] The battery cap may have a plurality of sealing reinforcement grooves on the side of the battery cap. The plurality of sealing reinforcement grooves may include a first sealing reinforcement groove formed in a concave shape at a position corresponding to the first sealing reinforcement protrusion; and a second sealing reinforcement groove formed in a concave shape at a position corresponding to the second sealing reinforcement protrusion.

[0026] In another embodiment of the present invention, the battery cap may have a sealing reinforcement projection formed protruding along the outer circumference of the side of the battery cap. In this case, the sealing gasket may have a sealing reinforcement groove formed by indentation along the inner circumference to be shape-matched to the sealing reinforcement projection.

[0027] According to one embodiment of the present invention, a battery pack comprising at least one battery cell is provided.

[0028] In addition, according to one embodiment of the present invention, a vehicle comprising at least one battery pack is provided.

[0029] A sealing gasket according to one embodiment of the present invention is a sealing gasket applied to a battery cell having a battery housing that accommodates an electrode assembly and a battery cap that covers an opening of the battery housing, and comprises: a lower gasket formed in a circular ring shape to support the lower edge portion of the battery cap; an intermediate gasket extending upward from the outer diameter portion of the lower gasket to contact the side of the battery cap and formed perpendicularly to the upper surface of the lower gasket; an upper gasket provided to extend above the intermediate gasket and having a thickness that changes in the vertical direction; and a groove portion provided in the connection portion between the intermediate gasket and the upper gasket to seal the space between the battery cap and the battery housing.

[0030] The upper gasket can be arranged to be bent to wrap around the edge of the battery cap by a crimping process.

[0031] The above groove may be formed in a portion corresponding to the upper edge corner of the battery cap, extending from the inner surface of the sealing gasket toward the interior of the sealing gasket.

[0032] The above groove may be formed to be inclined upward from the inner surface of the sealing gasket toward the interior of the sealing gasket.

[0033] The above intermediate gasket may be provided with a sealing reinforcing projection formed to protrude along the inner circumference of the intermediate gasket at the lower part of the groove.

[0034] According to an embodiment of the present invention, the sealing power and electrolyte leakage prevention performance of the battery cell can be improved, and electrolyte leakage caused by deformation of the sealing gasket due to the crimping process can be effectively prevented.

[0035] In addition, according to an embodiment of the present invention, alignment between the battery cap and the sealing gasket is maintained during the crimping process, and the crimping process can be performed in the correct position, thereby preventing lifting of the sealing gasket and abnormal sealing, and thus enhancing the sealing performance of the battery cell.

[0036] The effects obtainable through the present invention are not limited to those described above, and other unmentioned technical effects will be clearly understood by a person skilled in the art from the description of the invention below.

[0037] FIG. 1 is a perspective view showing a battery cell according to one embodiment of the present invention.

[0038] FIG. 2 is a cross-sectional perspective view of a battery cell according to an embodiment of FIG. 1.

[0039] FIG. 3 is a cross-sectional view of a battery cell according to an embodiment of FIG. 1.

[0040] Figure 4 is a cross-sectional view showing an enlarged view of section 'A' of Figure 3.

[0041] FIG. 5 is a cross-sectional view showing a sealing gasket and a battery cap constituting a battery cell according to an embodiment of the present invention.

[0042] FIG. 6 is a cross-sectional view showing the shape of a sealing gasket before the crimping process according to an embodiment of the present invention.

[0043] FIG. 7 is a cross-sectional view showing a part of a battery cap constituting a battery cell according to an embodiment of the present invention.

[0044] FIGS. 8 to 10 are drawings showing that the shape of a sealing gasket is deformed as the crimping process proceeds according to an embodiment of the present invention.

[0045] FIG. 11 is a diagram showing the sizing process being carried out according to an embodiment of the present invention.

[0046] FIG. 12 is a drawing for explaining the shape of the groove portion and the sealing reinforcing projection of the sealing gasket constituting the battery cell according to an embodiment of the present invention.

[0047] FIG. 13 is a drawing showing the appearance of a sealing gasket constituting a battery cell according to an embodiment of the present invention being deformed by a crimping process.

[0048] FIG. 14 is an enlarged view showing the groove portion of the sealing gasket and the sealing reinforcing projection and the sealing reinforcing groove of the battery cap according to an embodiment of the present invention.

[0049] FIG. 15 is a drawing showing a groove portion of a sealing gasket according to another embodiment of the present invention.

[0050] FIGS. 16 and 17 are drawings showing the groove portion of a sealing gasket according to another various embodiment of the present invention.

[0051] FIG. 18 is a drawing for explaining a sealing reinforcing projection of a sealing gasket according to another embodiment of the present invention.

[0052] FIG. 19 is a drawing illustrating a sealing reinforcing projection of a sealing gasket and a sealing reinforcing groove of a battery cap according to another embodiment of the present invention.

[0053] FIG. 20 is a cutaway perspective view showing a battery cell according to another embodiment of the present invention.

[0054] FIG. 21 is a cross-sectional view of a battery cell according to an embodiment of FIG. 20.

[0055] FIG. 22 is a drawing for explaining a battery pack including a battery cell according to an embodiment of the present invention.

[0056] FIG. 23 is a drawing for explaining a vehicle including a battery pack according to an embodiment of the present invention.

[0057] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Accordingly, in some embodiments, well-known process steps, well-known device structures, and well-known techniques are not specifically described to avoid the present invention being interpreted ambiguously. Throughout the specification, like reference numerals refer to like components.

[0058] In drawings, thicknesses may be enlarged to clearly represent multiple layers and regions. Throughout the specification, the same reference numerals are used for similar parts. When a part such as a layer, film, region, or plate is described as being "above" another part, this includes not only cases where it is "immediately above" another part, but also cases where there is another part in between. Conversely, when a part is described as being "immediately above" another part, it means that there is no other part in between. Furthermore, when a part such as a layer, film, region, or plate is described as being "below" another part, this includes not only cases where it is "immediately below" another part, but also cases where there is another part in between. Conversely, when a part is described as being "immediately below" another part, it means that there is no other part in between.

[0059] A battery cell according to an embodiment of the present invention is configured to seal the space between a battery cap and a battery housing, and a groove is provided on the inner surface of a sealing gasket that contacts the edge portion of the battery cap, taking into account deformation during the crimping process. The groove is formed on the inner surface of the sealing gasket corresponding to the upper edge corner of the battery cap. In order to effectively prevent leakage of the electrolyte due to deformation of the sealing gasket caused by the crimping process, the groove is formed to be inclined upward in a direction away from the edge of the battery cap (radial direction).

[0060] In addition, in the battery cell according to an embodiment of the present invention, a sealing reinforcement projection is formed on the lower side of the groove portion on the inner surface of the sealing gasket that contacts the side of the rim portion of the battery cap. A sealing reinforcement groove is formed on the side of the rim portion of the battery cap to be shape-matched and coupled with the sealing reinforcement projection of the sealing gasket. The sealing reinforcement projection of the sealing gasket and the sealing reinforcement groove of the battery cap ensure that alignment between the battery cap and the sealing gasket is maintained during the crimping process, thereby allowing the crimping process to proceed at an accurate position, and contribute to strengthening the sealing performance of the battery cell by preventing lifting of the sealing gasket and abnormal sealing.

[0061] For convenience of explanation, in this specification, the direction following the longitudinal direction of the winding axis of an electrode assembly wound in a jelly roll shape is referred to as the "axial direction," "vertical direction," or "height direction." The direction surrounding the winding axis is referred to as the "circumferential direction" or "peripheral direction." Furthermore, the direction approaching or moving away from the winding axis is referred to as the "radial direction." Among the radial directions, the direction approaching the winding axis may be referred to as the "centripetal direction," and the direction moving away from the winding axis may be referred to as the "centrifugal direction."

[0062] FIG. 1 is a perspective view showing a battery cell according to an embodiment of the present invention. FIG. 2 is a cross-sectional perspective view of a battery cell according to the embodiment of FIG. 1. FIG. 3 is a cross-sectional view of a battery cell according to the embodiment of FIG. 1. Referring to FIG. 1 to 3, a battery cell (1) according to an embodiment of the present invention includes an electrode assembly (10), a battery housing (20), a current collector (30), a battery cap (40), and a sealing gasket (50). The battery cell of the present invention is not limited to the shape of the battery cell shown in FIG. 1 to 3 and can be applied to batteries of other shapes. To avoid obscuring the essence of the present invention, components such as a busbar for electrical connection, a cooling unit, and a power terminal are omitted from the illustration.

[0063] A battery cell (1) according to one embodiment of the present invention may be a cylindrical secondary battery (cylindrical battery cell). An electrode assembly (10) may be provided in a cylindrical shape having a core and an outer surface, wherein a first electrode (e.g., a negative electrode), a second electrode (e.g., a positive electrode), and a separator interposed between these electrodes are wound around a winding axis. The electrode assembly (10) may be a jelly-roll type electrode assembly. An additional separator may be provided on the outer surface of the electrode assembly (10) for insulation from the battery housing (20). The electrode assembly (10) may be provided to have a winding structure well known in the art of the present invention without limitation.

[0064] The first electrode comprises a first electrode current collector and a first electrode active material applied on one or both sides of the first electrode current collector. At one end (upper end) in the width direction of the first electrode (a direction parallel to the height direction of the battery cell shown in FIG. 1), there is a non-coated portion where the first electrode active material is not applied. That is, the first electrode includes a non-coated portion exposed to the outside of the separator, where the active material is not coated at one long end along the winding direction. The non-coated portion functioning as the first electrode tab is referred to as the first non-coated portion (11). The first non-coated portion (11) is provided at the upper end with respect to the height direction of the electrode assembly (10) housed within the battery housing (20). At least a portion of the first non-coated portion (11) is used as an electrode tab itself. The first non-coated portion (11) may be, for example, a negative electrode tab.

[0065] The second electrode comprises a second electrode current collector and a second electrode active material applied on one or both sides of the second electrode current collector. Based on the width direction (height direction) of the second electrode, there is a non-exposed portion at the other end where the second electrode active material is not applied. That is, the second electrode includes a non-exposed portion along the winding direction where the active material is not coated at the other long end and is exposed to the outside of the separator. The non-exposed portion functioning as a second electrode tab is referred to as the second non-exposed portion (12). The second non-exposed portion (12) is provided at the bottom based on the height direction of the electrode assembly (10) housed within the battery housing (20). At least a portion of the second non-exposed portion (12) is used as an electrode tab itself. The second non-exposed portion (12) may be, for example, a positive electrode tab.

[0066] The battery housing (20) is a roughly cylindrical receptacle with an opening formed on one side, and may be provided, for example, with a conductive metal material. The battery housing (20) is configured to accommodate the electrode assembly (10) of the secondary battery. The side of the battery housing (20) and the lower surface located opposite the opening (20a) may be formed integrally. The battery housing (20) may be provided with the upper end open and the lower end closed in the height direction. The lower surface of the battery housing (20) may have a roughly flat shape. The battery housing (20) is configured to accommodate the electrode assembly (10) and the electrolyte through the opening (20a) formed on its upper end.

[0067] The battery housing (20) may have a beading portion (21) formed in an end region adjacent to an opening (20a) provided at the top thereof, and a crimping portion (22) formed on the beading portion (21). The beading portion (21) has a shape in which the outer circumference of the battery housing (20) is pressed in to a predetermined depth. The beading portion (21) may have a shape in which it is pressed inward in the region between the opening (20a) of the battery housing (20) and the internal receiving space that accommodates the electrode assembly (10).

[0068] The beading portion (21) provides a support surface on which a sealing gasket (50) and a battery cap (40) can be seated. Additionally, the beading portion (21) can provide a support surface on which at least a portion of the edge perimeter of a current collector (30) can be seated and joined. At least a portion of the edge perimeter of the current collector (30), at least a portion of the edge perimeter of the sealing gasket (50), and at least a portion of the edge perimeter of the battery cap (40) can be seated on the upper surface of the beading portion (21). The beading portion (21) can be formed by pressing the outer circumference of the battery housing (20) inward in an area adjacent to the opening (20a) of the battery housing (20) while the electrode assembly (10) is received within the battery housing (20) through the opening (20a).

[0069] In order to stably support the current collector (30), the battery cap (40), and the sealing gasket (50), the upper surface of the beading portion (21) may have a shape that extends along a direction approximately parallel to the lower surface of the battery housing (20), that is, a shape that extends in a direction approximately perpendicular to the side wall of the battery housing (20). The beading portion (21) can function as a support portion on which the battery cap (40), etc., is seated, while preventing the electrode assembly (10), which has a size corresponding to the inner diameter of the internal receiving space of the battery housing (20), from coming out through the opening (20a) formed at the top of the battery housing (20).

[0070] The crimping portion (22) extends upward from the beading portion (21) and is formed on the upper part of the beading portion (21). The crimping portion (22) has a bent shape that extends to wrap around the edge perimeter and part of the upper surface of the battery cap (40) placed on the upper part of the beading portion (21). The battery cap (40) is fixed on the beading portion (21) by the crimping portion (22). The crimping portion (22) may have a shape that extends inwardly from the upper perimeter of the battery housing (20) in the radial direction (centripetal direction) of the battery cell (1). The crimping portion (22) is provided in an area corresponding to the edge perimeter of the upper surface of the battery cap (40) to fix the battery cap (40) and prevent the battery cap (40) from moving upward.

[0071] The upper portion of the crimping portion (22) is formed by bending so that it extends inward by a predetermined distance along the radial direction of the battery cell (1) to wrap around a part of the upper surface of the battery cap (40), thereby securing the perimeter of the upper surface of the battery cap (40). The perimeter area of ​​the battery cap (40) is interposed between the upper portion of the crimping portion (22) and the beading portion (21) and is secured to the battery housing (20), covering the opening (20a) of the battery housing (20).

[0072] The current collector (30) is housed inside the battery housing (20). The current collector (30) is made of a conductive metal material and can be electrically connected to the electrode assembly (10). The current collector (30) can be electrically connected to the battery housing (20). That is, the current collector (30) can electrically connect the first electrode of the electrode assembly (10) and the battery housing (20). The current collector (30) may have a support portion (31), a tab coupling portion (32), and a housing coupling portion (33).

[0073] The support portion (31) and the tab connecting portion (32) of the current collector (30) are positioned on the upper part of the electrode assembly (10). The support portion (31) is positioned on one side of the electrode assembly (10). The tab connecting portion (32) extends from the support portion (31) and is connected to the first non-reinforcing portion (11) of the electrode assembly (10). The tab connecting portion (32) can be connected to the electrode assembly (10), for example, by welding a certain area while seated on the first non-reinforcing portion (11) of the electrode assembly (10). The tab connecting portion (32) of the current collector (30) may be located below the lower surface of the beading portion (21).

[0074] A through hole (not shown) may be formed in the current collector (30) to allow flames generated inside the battery cell (1) to escape smoothly. Accordingly, even if a thermal runaway phenomenon occurs on the side of the electrode assembly (10), the flames and venting gas generated from the electrode assembly (10) can be smoothly discharged through the through hole without being blocked by the current collector (30) located on the upper side of the electrode assembly (10). Therefore, it is possible to prevent the flames from moving toward the beading part (21) located in the vicinity of the electrode assembly (10) and the current collector (30) and causing pinholes in the beading part (21), and to prevent the fire from spreading to other battery cells (1) located around the battery cell (1) where the fire occurred.

[0075] The support member (31) may have a current collector hole (H2) formed at a position corresponding to a winding hole (H1) formed approximately in the center of the electrode assembly (10). The winding hole (H1) and the current collector hole (H2), which are in communication with each other, may function as a passage for inserting a welding rod for welding between the electrode terminal of the electrode assembly (10) and the current collector (30), or welding between the electrode terminal and a lead tab (not shown), or for irradiating a laser beam.

[0076] 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 obscured, which may reduce liquid injection performance, and it may also be difficult to secure sufficient space for inserting a welding device or laser irradiation. Therefore, so that the current collector hole (H2) does not obscure the winding hole (H1) formed in the core of the electrode assembly (10), the winding hole (H1) of the electrode assembly (10) may have a diameter substantially equal to or larger than that of the current collector hole (H2).

[0077] The housing coupling portion (33) extends from the support portion (31) to a periphery area and is coupled to the inner surface of the battery housing (20). The housing coupling portion (33) may extend from the support portion (31) and be electrically coupled to the inner surface of the battery housing (20). For example, the housing coupling portion (33) may be coupled to the upper surface of the beading portion (21) on the inner surface of the battery housing (20).

[0078] The inner diameter of the battery housing (20) in the area where the beading portion (21) is formed is formed to be smaller than the diameter of the electrode assembly (10). For stable contact and connection, the beading portion (21) may have a shape that extends along a direction approximately parallel to the lower surface of the battery housing (20), that is, a direction approximately perpendicular to the side wall of the battery housing (20). The housing connection portion (33) may be welded to the upper surface of the beading portion (21). For welding the connection between the battery housing (20) and the current collector (30), for example, laser welding, ultrasonic welding, or spot welding may be applied.

[0079] A battery cap (40) is provided to cover an opening (20a) of a battery housing (20). The battery cap (40) may be coupled to the battery housing (20) to seal the opening (20a) of the battery housing (20) through a crimping process via a sealing gasket (50). The battery cap (40) may be provided with a venting portion (41) formed to prevent an increase in internal pressure caused by gas generated inside the battery housing (20).

[0080] The venting portion (41) may be configured to break when the internal pressure of the battery housing (20) increases above a certain level. The venting portion (41) is formed in a part of the battery cap (40) and may be a structurally weaker area than the surrounding area so that it can easily break when pressure is applied to the inside due to thermal runaway, etc. For example, the venting portion (41) may be an area having a thinner thickness compared to the surrounding area. The venting portion (41) may be formed as a roughly circular closed loop.

[0081] The battery cap (40) covers an opening (20a) formed on one side of the battery housing (20). The battery cap (40) can be secured by a crimping portion (22) formed on the top of the battery housing (20). To improve the fixing force and the sealing of the battery housing (20), a sealing gasket (50) is interposed between the battery housing (20) and the battery cap (40), and between the current collector (30) and the battery cap (40). Accordingly, the current collector (30) can be interposed between the beading portion (21) of the battery housing (20) and the sealing gasket (50). The current collector (30) interposed between the beading portion (21) and the sealing gasket (50) can be secured by bending the crimping portion (22) which extends upward from the beading portion (21).

[0082] A sealing gasket (50) is provided to surround the battery cap (40) and seal the space between the battery cap (40) and the battery housing (20). The sealing gasket (50) serves to maintain airtightness between the battery housing (20) and the battery cap (40). If the sealing performance of the sealing gasket (50) is not good, moisture may penetrate into the battery housing (20) or the electrolyte or gas inside the battery housing (20) may leak out through a small gap between the battery housing (20) and the battery cap (40). Since the sealing gasket (50) undergoes deformation due to the crimping process, a structure that strengthens the sealing force is required to account for the shape deformation of the sealing gasket (50) caused by the crimping process.

[0083] FIG. 4 is an enlarged cross-sectional view of section 'A' of FIG. 3. FIG. 5 is a cross-sectional view showing a sealing gasket and a battery cap constituting a battery cell according to an embodiment of the present invention. FIG. 6 is a cross-sectional view showing the shape of the sealing gasket before the crimping process according to an embodiment of the present invention. FIG. 7 is a cross-sectional view showing a part of the battery cap constituting a battery cell according to an embodiment of the present invention.

[0084] Referring to FIGS. 4 to 7, the sealing gasket (50) has a groove (54) in the corner portion between the upper edge of the battery cap (40) and the side formed along the circumferential direction of the battery cap (40). The groove (54) is formed in the folded portion of the inner surface of the sealing gasket (50) where deformation occurs most significantly during the crimping process. In order to improve the sealing force while mitigating the force applied to the folded portion of the sealing gasket (50) during the crimping process, the groove (54) is formed to be inclined upward in a direction away from the edge of the battery cap (40).

[0085] FIGS. 8 to 10 are drawings showing the deformation of the shape of a sealing gasket as the crimping process proceeds according to an embodiment of the present invention. FIG. 11 is a drawing showing the sizing process proceeding according to an embodiment of the present invention. FIG. 12 is a drawing for explaining the shape of the groove portion and the sealing reinforcement protrusion of the sealing gasket constituting a battery cell according to an embodiment of the present invention. FIG. 13 is a drawing showing the deformation of the sealing gasket constituting a battery cell by the crimping process according to an embodiment of the present invention. FIG. 14 is an enlarged drawing showing the groove portion and the sealing reinforcement protrusion of the sealing gasket and the sealing reinforcement groove of the battery cap according to an embodiment of the present invention.

[0086] Referring to FIGS. 4 to 14, the upper portions of the sealing gasket (50) and the battery housing (20) are bent by a crimping process to wrap around the edge of the battery cap (40) (see FIGS. 8 to 10). That is, a crimping process is performed to form the end of the battery housing (20) that extends upward from the beading portion (21) so that the battery housing (20) and the sealing gasket (50) together wrap around the edge of the battery cap (40).

[0087] FIG. 8 illustrates the first crimping process, FIG. 9 illustrates the second crimping process, and FIG. 10 illustrates the third crimping process. As the first crimping process, the second crimping process, and the third crimping process are performed sequentially, the height (L0, L1, L2) of the crimping section (22) from the beading section (21) to the top of the battery housing (20) is gradually reduced, and the space between the battery cap (40) and the battery housing (20) is sealed by the crimping section (22) through the sealing gasket (50).

[0088] The crimping portion (22) is formed by bending the open end of the battery housing (20) and the upper end of the sealing gasket (50). By the crimping process, the open portion (20a) of the battery housing (20) is sealed by the bent upper portion of the battery housing (20), the sealing gasket (50), and the battery cap (40). The outer diameter (L3) of the crimping portion (22) can be provided to be approximately the same as the outer diameter of the lower region of the battery housing (20) in which the electrode assembly (10) is received.

[0089] To ensure sealing performance, the sealing gasket (50) may include a lower gasket (51), an intermediate gasket (52), an upper gasket (53), a groove (54), and a sealing reinforcing projection (55), as shown in FIG. 5. The lower gasket (51), the intermediate gasket (52), the upper gasket (53), and the sealing reinforcing projection (55) are terms used to designate distinct areas of the sealing gasket (50), and can all be made of the same material to form a single sealing gasket (50) that is integrally molded.

[0090] The lower gasket (51) may be formed in a circular ring shape to support the lower edge portion of the battery cap (40). The lower edge portion of the battery cap (40) contacts the upper surface of the lower gasket (51). To this end, the inner diameter of the lower gasket (51) may be provided with a diameter smaller than the outer diameter of the battery cap (40). A housing coupling portion (33) of the current collector (30) is interposed between the lower surface of the lower gasket (51) and the upper surface of the beading portion (21). The lower gasket (51) is positioned on the lower region side of the crimping portion (22).

[0091] The intermediate gasket (52) extends upward from the outer diameter portion of the lower gasket (51) so as to be in contact with the side of the battery cap (40). The intermediate gasket (52) may be formed perpendicular to the upper surface of the lower gasket (51). The inner diameter portion of the intermediate gasket (52) contacts the outer diameter portion of the battery cap (40). That is, the inner diameter of the intermediate gasket (52) may be provided with the same diameter as the outer diameter of the battery cap (40). The outer diameter portion of the intermediate gasket (52) contacts the inner diameter portion of the intermediate area of ​​the crimping portion (22) of the battery housing (20).

[0092] The upper gasket (53) is provided to extend over the upper portion of the intermediate gasket (52). To improve sealing power by taking into account shape deformation during the crimping process, the thickness of the upper gasket (53) may vary along its length. In one embodiment, the upper gasket (53) may be designed to have a shape in which the thickness gradually increases from the top of the intermediate gasket (52) toward the top, and then decreases again.

[0093] The upper gasket (53) is a part that is folded inward and bent to wrap around the edge of the battery cap (40) during the crimping process. The connection between the middle gasket (52) and the upper gasket (53) corresponds to the part that is folded by the crimping process. The connection between the middle gasket (52) and the upper gasket (53) may be located at a position corresponding to the upper edge corner of the battery cap (40).

[0094] The groove (54) may be provided in the connection between the intermediate gasket (52) and the upper gasket (53) so as to seal the space between the battery cap (40) and the battery housing (20) without being affected by deformation during the crimping process. The groove (54) is formed to be inclined upward from the connection between the intermediate gasket (52) and the upper gasket (53) toward the edge of the battery cap (40). The groove (54) may be formed in an overall ring shape that is wider at the top and narrower at the bottom by extending along the circumference of the sealing gasket (50).

[0095] As described above, in the battery cell (1) according to the embodiment of the present invention, a groove (54) is formed on the inner surface of the sealing gasket (50) where the sealing gasket (50) and the battery cap (40) come into contact during the crimping process, so as to be inclined upward in the centripetal direction. According to the embodiment of the present invention, the force (reference numeral F1 of FIG. 13) applied to the folding part during the crimping process is mitigated by the groove (54), and the force of interlocking with the battery cap (40) is improved, thereby preventing deterioration of sealing performance due to shape deformation of the folding part during the crimping process. Accordingly, the sealing performance of the sealing gasket (50) can be further strengthened.

[0096] In order to enhance the above-described effect, one end of the groove (54) located on the inner surface of the sealing gasket (50) is provided to be in contact with the upper edge corner of the rim of the battery cap (40). Considering the shape deformation caused by compression of the sealing gasket (50) during the crimping process, the groove (54) may be formed at an angle (θ1) of 30° to 60° relative to a horizontal plane parallel to the upper surface of the battery cap (40). More preferably, the groove (54) may be formed at an angle of 40° to 50° relative to the horizontal plane. This is because, since the upper gasket (53) is bent approximately 90°, forming the groove (54) at an angle of approximately 45° suppresses deformation of the sealing gasket (50) during the crimping process, thereby effectively preventing weakening of the sealing performance caused by deformation of the sealing gasket (50).

[0097] Based on the crimping process before and / or after the crimping process, the groove (54) may be formed such that the depth from one end to the other (reference numeral D1 in FIG. 12) is 30% to 70% of the thickness (reference numeral T1 in FIG. 12) of the sealing gasket (50) defined based on the direction of the groove (54). It is preferable to set the groove depth (D1) of the groove (54) of the sealing gasket (50) to a depth of 50% or less of the total thickness (T1) of the sealing gasket (50). This is to design the groove depth (D1) of the groove (54) to an appropriate length so that it acts as a sufficient buffer in the area of ​​deformation of the sealing gasket (50) during the crimping process, thereby preventing deterioration of sealing performance due to deformation of the sealing gasket (50), while at the same time limiting the depth of the groove (54) to maintain sealing performance through the thickness of the sealing gasket (50).

[0098] In the embodiment of FIG. 14, the width (W1) of the groove (54) is formed uniformly along the length direction of the groove (54), but the width (W1) of the groove (54) may be formed to vary along the length direction of the groove (54). The groove (54) may be formed by a mold during the molding of the sealing gasket (50), or it may be formed through a cutting process using a cutting tool or a cutting process using a laser, etc., after the molding of the sealing gasket (50).

[0099] The middle gasket (52) of the sealing gasket (50) may be provided with a sealing reinforcing projection (55) at the lower part of the groove (54). The sealing reinforcing projection (55) may be formed protruding along the inner circumference of the middle gasket (52). The sealing reinforcing projection (55) may be formed at a position that contacts the side perpendicular to the upper and lower edges of the battery cap (40). In one embodiment, the sealing reinforcing projection (55) may be provided as a projection protruding in a triangular shape from the inner surface of the middle gasket (52).

[0100] The battery cap (40) may be provided with a sealing reinforcement groove (42) formed by an indentation on the side of the battery cap (40) to be shaped and coupled to a sealing reinforcement projection (55). The sealing reinforcement groove (42) may be provided as a groove of the same size and shape as the sealing reinforcement projection (55). Thus, if the sealing reinforcement projection (55) is provided as a triangular-shaped projection, the sealing reinforcement groove (42) may be provided as a triangular-shaped groove. The sealing reinforcement projection (55) and the sealing reinforcement groove (42) may be located at the center of the thickness direction of the battery cap (40).

[0101] The sealing reinforcement protrusion (55) performs the function of aligning the battery cap (40) and the sealing gasket (50) during the crimping process and ensuring that the crimping process proceeds at an accurate position. Accordingly, the sealing reinforcement protrusion (55) and the sealing reinforcement groove (42) prevent lifting of the sealing gasket (50) and abnormal sealing, thereby enhancing the sealing performance. The vertical size of the sealing reinforcement protrusion (55) may be 10% to 30% of the thickness of the edge portion of the battery cap (40) (reference numeral T2 in FIG. 12). It is preferable to set the size of the sealing reinforcement protrusion (55) to 20% or less of the thickness (T2) of the battery cap (40).

[0102] The sealing reinforcement projection (55) may have a lower projection surface (55a) that protrudes obliquely with respect to the side of the intermediate gasket (52) and an upper projection surface (55b) that protrudes obliquely with respect to the side of the intermediate gasket (52). The lower projection surface (55a) may contact the lower surface of the sealing reinforcement groove (42) of the battery cap (40), and the upper projection surface (55b) may contact the upper surface of the sealing reinforcement groove (42) of the battery cap (40). In order to stably maintain the relative position of the sealing gasket (50) and the battery cap (40), the lower projection surface (55a) and the upper projection surface (55b) may each be formed to protrude obliquely at an angle of about 30° to 60° with respect to the side of the intermediate gasket (52).

[0103] The lower protrusion surface (55a) and the upper protrusion surface (55b) may be formed to be inclined at the same angle with respect to the side of the intermediate gasket (52), or may be formed to protrude at different angles. For example, the lower protrusion surface (55a) may be formed at a gentler angle with respect to the side of the intermediate gasket (52) than the upper protrusion surface (55b). In this case, the sealing reinforcing protrusion (55) of the sealing gasket (50) can be inserted more smoothly around the battery cap (40). Additionally, the upper protrusion surface (55b) may be formed at a larger angle of inclination with respect to the side of the intermediate gasket (52) than the lower protrusion surface (55a), so that the upper protrusion surface (55b) of the sealing reinforcing protrusion (55) of the sealing gasket (50) can be maintained in a state of being caught on the upper surface of the sealing reinforcing groove (42), thereby more reliably preventing the sealing gasket (50) from lifting during the crimping process.

[0104] The sealing reinforcement groove (42) can be formed to be recessed at the same angle as the lower surface (55a) and the upper surface (55b) of the sealing reinforcement projection (55). The sealing reinforcement projection (55) can be formed integrally during the molding of the sealing gasket (50). The sealing reinforcement groove (42) can be molded during the manufacture of the battery cap (40), or it can be formed by cutting the side portion of the battery cap (40) after the battery cap (40) has been manufactured.

[0105] FIG. 15 is a drawing showing a groove portion of a sealing gasket according to another embodiment of the present invention. Referring to FIG. 15, the sealing gasket (50) may have two or more groove portions (54a, 54b). The plurality of groove portions (54a, 54b) may include a first groove portion (54a) and a second groove portion (54b). Based on the prior crimping process, the first groove portion (54a) may be formed at a first angle (θ2) with respect to the horizontal direction, and the second groove portion (54b) may be formed at a second angle (θ3) greater than the first angle (θ2) with respect to the horizontal direction.

[0106] The first angle (θ2) of the first groove (54a) may be 15° to 45°, and the second angle (θ3) of the second groove (54b) may be 45° to 75°. The angle between the plurality of grooves (54a, 54b) may be 20° to 40°. According to the embodiment of FIG. 15, the deterioration of sealing performance due to deformation during the crimping process of the sealing gasket (50) can be prevented more effectively by means of the plurality of grooves (54a, 54b). In the illustrated example, two grooves (54a, 54b) are formed in the sealing gasket (50), but three or more grooves may be formed in the sealing gasket (50) at different angles.

[0107] FIGS. 16 and 17 are drawings showing a groove of a sealing gasket according to another various embodiment of the present invention. The groove (54) of the sealing gasket (50) shown in FIGS. 16 and 17 differs from the previously described embodiments in that the width changes along the depth direction of the groove (54) based on the prior crimping process. The width of the groove (54) may decrease linearly as shown in FIG. 16 or non-linearly as shown in FIG. 17 as the depth of the groove (54) increases.

[0108] During the crimping process, the inner side of the sealing gasket (50) is folded, and a strong compressive force is applied to the inner side of the sealing gasket (50). In this way, considering that the compressive force acts differently along the thickness direction of the sealing gasket (50) during the crimping process, the deformation of the sealing gasket (50) can be effectively absorbed by changing the width of the groove (54) along the depth direction. Accordingly, according to the embodiments of FIGS. 16 and 17, the width of the groove (54) is designed differently depending on the depth of the groove (54), so that the deterioration of sealing performance can be effectively prevented in response to the deformation that occurs differently depending on the depth of the groove (54) during the crimping process.

[0109] FIG. 18 is a drawing for illustrating a sealing reinforcing projection of a sealing gasket according to another embodiment of the present invention. Referring to FIG. 18, the sealing gasket (50) may have a plurality of sealing reinforcing projections (55c, 55d). A first sealing reinforcing projection (55c) may be formed protrudingly in the lower side area of ​​the intermediate gasket (52), and a second sealing reinforcing projection (55d) may be formed protrudingly in the upper side area of ​​the intermediate gasket (52) so as to be located above the first sealing reinforcing projection (55c).

[0110] Additionally, the sealing reinforcement grooves (42) of the battery cap may be formed in multiple numbers to correspond to the sealing reinforcement protrusions (55) of the sealing gasket (50). The first sealing reinforcement groove (42a) may be formed in a concave shape corresponding to the first sealing reinforcement protrusion (55c), and the second sealing reinforcement groove (42b) may be formed in a concave shape corresponding to the second sealing reinforcement protrusion (55d). According to the embodiment of FIG. 18, the position of the sealing gasket (50) can be maintained more reliably during the crimping process by means of the multiple sealing reinforcement protrusions (55c, 55d) and the multiple sealing reinforcement grooves (42a, 42b), so that the crimping process can be performed with the sealing gasket (50) in a fixed position.

[0111] FIG. 19 is a drawing illustrating a sealing reinforcing projection of a sealing gasket and a sealing reinforcing groove of a battery cap according to another embodiment of the present invention. Referring to FIG. 19, the sealing reinforcing projection (55) of the sealing gasket (50) and the sealing reinforcing groove (42) of the battery cap (40) may be designed to have shapes such as a semicircular cross-section or an elliptical cross-section in addition to forming a triangular projection. Furthermore, the sealing reinforcing projection (55) and the sealing reinforcing groove (42) may be formed in an asymmetrical structure in addition to a structure symmetrical in the vertical direction.

[0112] During the crimping process, the upper gasket (53) of the sealing gasket (50) is pressed inward and bent. During the crimping process, the sealing reinforcing protrusion (55) of the sealing gasket (50) is inserted into the sealing reinforcing groove (42) and maintains a state of close contact. In order to maintain a state of close contact between the sealing gasket (50) and the battery cap (40) more reliably, it is preferable that the sealing reinforcing protrusion (55) be formed on the sealing gasket (50) and the sealing reinforcing groove (42) be formed on the battery cap (40), but it is also possible to form the sealing reinforcing groove on the sealing gasket (50) and the sealing reinforcing protrusion on the battery cap (40).

[0113] In another embodiment of the present invention, a first sealing reinforcement projection and a first sealing reinforcement groove are each formed on the inner circumference of the sealing gasket (50), and a second sealing reinforcement groove coupled to the first sealing reinforcement projection of the sealing gasket (50) and a second sealing reinforcement projection coupled to the first sealing reinforcement groove of the sealing gasket (50) may each be formed on the outer circumference of the battery cap (40).

[0114] FIG. 20 is a cutaway perspective view showing a battery cell according to another embodiment of the present invention. FIG. 21 is a cross-sectional view of a battery cell according to the embodiment of FIG. 20. Since the groove portion of the sealing gasket, the sealing reinforcing projection, and the sealing reinforcing groove of the battery cap constituting the battery cell according to FIG. 20 and FIG. 21 are similar to the previously described embodiment, redundant descriptions of configurations that are substantially identical or similar to the previous embodiment will be omitted, and the explanation will focus on the differences from the previous embodiment.

[0115] In the battery cell (1) of FIGS. 20 and 21, the current collector (30) is electrically connected to the battery cap (40). A lead (34) may be connected to the current collector (30), and the lead (34) may be connected to the battery cap (40) by extending upward and directly to the battery cap (40) or to a connecting plate (70) connected to the lower surface of the battery cap (40). Thus, the battery cap (40) may have the same first polarity as the first non-removable portion (11) and may function as a first electrode terminal. A separator (13) for insulation from the battery housing (20) may be interposed on the outer surface of the electrode assembly (10).

[0116] An insulating plate (60) is positioned between the top of the electrode assembly (10) and the beading portion (21), or between the current collector (30) coupled to the top of the electrode assembly (10) and the beading portion (21), thereby preventing contact between the first non-contacting portion (11) and the battery housing (20), or between the current collector (30) and the battery housing (20). The insulating plate (60) has a lead hole through which a lead (34) extending upward from the current collector (30) or from the first electrode tab can be drawn out. The lead (34) can be drawn out upward through the lead hole and coupled to the lower surface of the connecting plate (70) or the lower surface of the battery cap (40).

[0117] The battery cap (40) may be made of a conductive metal material. The battery cap (40) may be configured to cover the upper opening of the battery housing (20). The battery cap (40) may be electrically connected to the first electrode of the electrode assembly (10). Additionally, the battery cap (40) may be electrically insulated from the battery housing (20). Thus, the battery cap (40) has the same first polarity as the first electrode of the electrode assembly (10) and may function as the first electrode terminal of the cylindrical battery cell (1). The electrical connection between the first electrode and the battery cap (40) may be made, for example, by a current collector (30) and / or a lead (34).

[0118] The battery cap (40) may be formed to protrude upward from approximately its center. More specifically, the approximately central portion of the battery cap (40) may be configured to protrude upward. The battery cap (40) may be provided at a position corresponding to the winding center hole formed at approximately the center of the battery cell (1). The battery cap (40) may protrude upward higher than the upper surface of the battery housing (20) to facilitate contact with electrical connection components such as a bus bar.

[0119] A sealing gasket (50) is interposed between the battery cap (40) and the crimping portion (22) of the battery housing (20) to seal the upper opening of the battery housing (20) and electrically insulate the battery housing (20) from the battery cap (40). The sealing gasket (50) may include a material having insulating and elastic properties. The sealing gasket (50) may include, for example, a polymer resin.

[0120] FIG. 22 is a drawing for explaining a battery pack including battery cells according to an embodiment of the present invention. Referring to FIG. 22, 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 an embodiment of the present invention as described above are electrically connected, and a pack housing (2) that accommodates the same. FIG. 23 is a drawing for explaining a vehicle including the battery pack of FIG. 22.

[0121] Referring to FIG. 23, the 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) may include 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.

[0122] Although the present invention has been described above by limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs.

Claims

1. A battery housing configured to accommodate an electrode assembly of a secondary battery and having an opening on one side; A battery cap coupled to the battery housing to cover the opening of the battery housing; and It includes a sealing gasket that wraps around the battery cap to seal the space between the battery cap and the battery housing, and The sealing gasket and the upper part of the battery housing are configured to be bent by a crimping process to wrap around the edge of the battery cap, and The above sealing gasket has a groove portion in a part corresponding to the upper surface corner of the rim of the battery cap, a battery cell.

2. In Paragraph 1, A battery cell, wherein the above-mentioned groove is formed to be inclined upward in a direction away from the edge of the battery cap.

3. In Paragraph 1, A battery cell, wherein one end of the groove portion located on the inner surface of the sealing gasket contacts the upper edge of the rim of the battery cap.

4. In Paragraph 3, A battery cell, wherein the above-mentioned groove is formed at an angle of 30° to 60° with respect to a horizontal plane parallel to the upper surface of the battery cap.

5. In Paragraph 4, A battery cell in which the depth from the one end to the other end is formed to be 30% to 70% of the thickness of the sealing gasket defined based on the direction of the groove.

6. In Paragraph 1, The sealing gasket has a plurality of grooves in a portion corresponding to the upper edge of the rim of the battery cap, and A plurality of the above-mentioned grooves include a first groove and a second groove formed on the upper part of the first groove, and Based on the state before the crimping process, the first groove is formed at a first angle with respect to the horizontal direction, and A battery cell, wherein, based on the prior crimping process, the second groove is formed at a second angle greater than the first angle with respect to the horizontal direction.

7. In Paragraph 1, A battery cell in which the width of the groove changes along the depth direction of the groove based on the prior crimping process.

8. In Paragraph 7, A battery cell in which the width of the above-mentioned groove decreases linearly as the depth increases from the inner surface of the sealing gasket.

9. In Paragraph 7, A battery cell in which the width of the above-mentioned groove decreases non-linearly as the depth increases from the inner surface of the sealing gasket.

10. In Paragraph 1, A battery cell having a sealing gasket having a sealing reinforcing projection formed to protrude along the inner circumference of the sealing gasket at the lower part of the groove.

11. In Paragraph 10, A battery cell, wherein the above-mentioned sealing reinforcement protrusion is formed at a position in contact with a side perpendicular to the upper and lower edges of the battery cap.

12. In Paragraph 11, A battery cell in which the vertical size of the sealing reinforcement protrusion is 10% to 30% of the thickness of the edge portion of the battery cap.

13. In Paragraph 11, A battery cell having a battery cap having a sealing reinforcement groove formed by recessing in the side of the battery cap to be shape-matched to the sealing reinforcement projection.

14. In Paragraph 13, The sealing gasket is provided with a plurality of sealing reinforcing protrusions along the inner circumference of the sealing gasket, and A battery cell comprising a plurality of sealing reinforcement protrusions, the plurality of sealing reinforcement protrusions including a first sealing reinforcement protrusion and a second sealing reinforcement protrusion formed on the upper portion of the first sealing reinforcement protrusion.

15. In Paragraph 14, The above battery cap is provided with a plurality of sealing reinforcement grooves on the side of the above battery cap, and The plurality of the above-mentioned sealing reinforcement grooves A first sealing reinforcement groove formed in a concave shape at a position corresponding to the first sealing reinforcement projection; and A battery cell comprising a second sealing reinforcement groove formed in a concave shape at a position corresponding to the second sealing reinforcement projection.

16. In Paragraph 1, The above battery cap is provided with a sealing reinforcing projection formed to protrude along the outer circumference of the side of the battery cap, and A battery cell having a sealing reinforcing groove formed by recessing along the inner circumference of the sealing gasket to be shape-matched to the sealing reinforcing projection.

17. A battery pack comprising at least one battery cell as described in paragraph 1.

18. A sealing gasket applied to a battery cell comprising a battery housing that accommodates an electrode assembly and a battery cap that covers an opening of the battery housing, wherein A lower gasket formed in a circular ring shape to support the lower portion of the rim of the battery cap; An intermediate gasket extending upward from the outer diameter portion of the lower gasket to contact the side of the battery cap and formed perpendicularly to the upper surface of the lower gasket; An upper gasket provided to extend above the intermediate gasket and having a thickness that changes in the vertical direction; and A groove provided in the connection portion between the intermediate gasket and the upper gasket to seal the space between the battery cap and the battery housing; The upper gasket is arranged to be bent to wrap around the edge of the battery cap by a crimping process, and The above-mentioned groove is a sealing gasket formed from the inner surface of the sealing gasket toward the interior of the sealing gasket at a portion corresponding to the upper edge of the rim of the battery cap.

19. In Paragraph 18, The above-mentioned groove is formed to be inclined upward from the inner surface of the sealing gasket toward the interior of the sealing gasket, a sealing gasket.

20. In Paragraph 18, The above intermediate gasket is a sealing gasket having a sealing reinforcing projection formed to protrude along the inner circumference of the intermediate gasket at the lower part of the groove.

Images