Electrolyte leakage prevention O-ring

Abstract

An O-ring according to one embodiment of the present invention includes a first part that is placed on the inwardly recessed beading portion of the battery housing, and a second part that is located above the first part and is configured to cover the upper end surface of the battery housing.

Description

[Technical Field]

[0001] The present invention relates to an O-ring for preventing leakage of an electrolyte.

[0002] This application claims priority based on Korean Patent Application No. 10-2023-0096275, filed on July 24, 2023, the entire contents of which are incorporated herein by reference in their entirety in the specification and drawings thereof.

[0003] This application claims priority based on Korean Patent Application No. 10-2024-0092210, filed on July 12, 2024, the entire contents of which are incorporated herein by reference in their entirety in the specification and drawings thereof. [Background technology]

[0004] Secondary batteries, which are easily applicable to various products and have electrical properties such as high energy density, are commonly used not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs), which are powered by electrical sources. These secondary batteries are attracting attention as a new energy source that is environmentally friendly and improves energy efficiency because they not only have the main advantage of dramatically reducing the use of fossil fuels but also have the advantage of not producing any by-products from energy use.

[0005] Currently, widely used types of secondary batteries include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. The operating voltage of such unit secondary battery cells, i.e., unit battery cells, is approximately 2.5V to 4.5V. Therefore, if a higher output voltage is required, a battery pack may be configured by connecting multiple battery cells in series. Alternatively, a battery pack may be configured by connecting multiple battery cells in parallel depending on the required charge / discharge capacity of the battery pack. Therefore, the number of battery cells included in the battery pack may be variously set depending on the required output voltage and / or charge / discharge capacity.

[0006] Meanwhile, during the manufacture of cylindrical secondary batteries, an electrode assembly is inserted into a battery housing and then an electrolyte injection process is performed for activation. During this process, an O-ring is installed to prevent the electrolyte from leaking out of the battery housing. However, with conventional O-rings, there is a problem of electrolyte leakage due to a decrease in sealing performance caused by contact with the battery housing. Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, in order to solve the above problem, an object of the present invention is to provide an O-ring that can prevent electrolyte from leaking outside the battery housing when electrolyte is poured into a cylindrical battery cell.

[0008] More specifically, the present invention aims to increase the contact area between the battery housing and the O-ring, thereby improving sealing characteristics.

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

[0010] An O-ring according to one embodiment of the present invention for solving the above problem includes a first part that is placed on an inwardly recessed beading portion of a battery housing, and a second part that is positioned above the first part and is configured to cover the upper end surface of the battery housing.

[0011] In one embodiment of the present invention, the first part may be configured in a cylindrical shape.

[0012] In another aspect of the present invention, the O-ring may be elastic.

[0013] Desirably, the O-ring may include at least one of NBR (nitrile butadiene rubber), VMQ (vinyl methyl silicone rubber), FKM (fluoroelastomer), and FPM (fluororubber).

[0014] In still another aspect of the present invention, the O-ring may include a liquid injection hole that penetrates vertically in the center.

[0015] In one embodiment of the present invention, the O-ring may have a groove into which a hopper capable of applying pressure to the O-ring is inserted.

[0016] In another aspect of the present invention, the outer surface of the first part may be configured to be spaced apart from the inner surface of the battery housing by a predetermined distance.

[0017] Preferably, the outer surface of the first part is configured to be spaced apart from the inner surface of the battery housing by 0.2 mm to 0.8 mm.

[0018] In still another aspect of the present invention, the lower surface of the second part may be configured to be spaced a predetermined distance from the upper end surface of the battery housing.

[0019] In one aspect of the present invention, the O-ring may include a pressure surface provided inside or outside the O-ring and configured to be pressed downward by the hopper.

[0020] Preferably, the first part may be configured so that when the pressure surface is pressed downward, the first part is compressed in the vertical direction and increases in width in the radial direction.

[0021] In another aspect of the present invention, the second part may be configured to move downward and contact an upper end surface of the battery housing when the pressure surface is pressed downward.

[0022] In yet another aspect of the present invention, the O-ring may be configured to isolate the outside and inside of the battery housing when pressure is applied from the outside of the battery housing toward the beading portion of the battery housing.

[0023] In still another embodiment of the present invention, the thickness of the first part may alternately increase and decrease along the circumferential direction. [Effects of the Invention]

[0024] According to the present invention, when an electrolyte is poured into a cylindrical battery cell, leakage of the electrolyte to the outside of the battery housing can be prevented.

[0025] Furthermore, according to the present invention, the contact area between the battery housing and the O-ring can be increased.

[0026] As a result, according to the present invention, the sealing performance of the battery cell can be improved when the electrolyte is injected.

[0027] However, the effects obtained by the present invention are not limited to the above-mentioned effects, and other technical effects not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.

[0028] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention, serve to further understand the technical concepts of the present invention. Therefore, the present invention should not be interpreted as being limited to only the matters described in the drawings. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a diagram illustrating a battery cell according to an embodiment of the present invention; [Figure 2] FIG. 2 is a vertical cross-sectional perspective view of FIG. [Figure 3] FIG. 2 is a longitudinal cross-sectional view of the battery cell of FIG. 1. [Figure 4] FIG. 10 is a diagram illustrating a conventional O-ring. [Figure 5] FIG. 10 is a diagram illustrating a state before a conventional O-ring is compressed. [Figure 6] FIG. 10 is a diagram illustrating a state after a conventional O-ring has been compressed. [Figure 7] 1A and 1B are diagrams illustrating an O-ring according to an embodiment of the present invention. [Figure 8] FIG. 8 is a diagram for explaining the state before the O-ring in FIG. 7 is compressed. [Figure 9] FIG. 9 is an enlarged view of a part of FIG. 8. [Figure 10] FIG. 8 is a diagram for explaining a state after the O-ring in FIG. 7 has been compressed. [Figure 11] 10A and 10B are diagrams illustrating an O-ring according to another embodiment of the present invention. [Figure 12] 10A and 10B are diagrams illustrating an O-ring according to still another embodiment of the present invention. [Figure 13] 10A and 10B are diagrams illustrating an O-ring according to still another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms and words used in this specification and claims should not be construed as being limited to their ordinary and dictionary meanings, but should be construed as meanings and concepts corresponding to the technical ideas of the present invention, based on the principle that the inventors themselves can appropriately define the concepts of terms in order to best describe the invention. Therefore, it should be understood that the configurations shown in the embodiments described in this specification are merely the most preferred embodiment of the present invention and do not represent the entire technical ideas of the present invention, and therefore various equivalents and modifications that can be substituted therefor may exist at the time of filing this application.

[0031] In order to facilitate understanding of the invention, the accompanying drawings may not be drawn to scale, and the dimensions of some components may be exaggerated. In addition, the same reference numerals may be used to refer to the same components in different embodiments.

[0032] When two comparison objects are identical, it means that they are "substantially identical." Therefore, "substantially identical" can include cases where there is a deviation that is considered to be a low level in the art, for example, a deviation within 5%. Furthermore, when a parameter in a given region is uniform, it can mean that the parameter is uniform on average.

[0033] Although terms such as "first" and "second" are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and it goes without saying that a first component is also a second component unless otherwise specified.

[0034] Throughout the specification, unless specifically stated to the contrary, each element may be singular or plural.

[0035] When any structure is disposed "on (or under)" a component or "above (or below)" a component, it can mean not only that the structure is disposed in contact with the upper surface (or lower surface) of the component, but also that other structures can be interposed between the component and any structure disposed on (or below) the component.

[0036] Furthermore, when a component is described as being "coupled," "coupled," or "connected" to another component, it should be understood that the components can be directly coupled or connected to each other, but that other components may be "intervening" between the components, or that each component may be "coupled," "coupled," or "connected" via other components.

[0037] Throughout the specification, "A and / or B" means A, B, or A and B, unless otherwise specified, and "C through D" means at least C and at most D, unless otherwise specified.

[0038] Fig. 1 is a diagram for explaining a battery cell 1 according to one embodiment of the present invention, and Fig. 2 is a vertical cross-sectional perspective view of Fig. 1. Fig. 3 is a vertical cross-sectional view of the battery cell 1 of Fig. 1.

[0039] A battery cell 1 according to one embodiment of the present invention includes an electrode assembly 10, a battery housing 20, and a current collector 30. The battery cell 1 may further include a terminal 50 and / or a second current collector 60. The present invention is not limited by the shape of the battery, and may also be applied to batteries of other shapes, such as prismatic batteries.

[0040] The electrode assembly 10 includes a first uncoated region 11 and a second uncoated region 12. More specifically, the electrode assembly 10 has a structure in which a first electrode, a second electrode, and a separator interposed therebetween are wound around a winding axis, thereby defining a core and an outer periphery. That is, the electrode assembly 10 applicable to the present invention may be a jelly roll-type electrode assembly 10. The electrode assembly 10 may be wound around a winding center hole H1. In this case, an additional separator may be provided on the outer periphery of the electrode assembly 10 for insulation from the battery housing 20. The electrode assembly 10 may have any winding structure known in the art. 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 may be any active material known in the art.

[0041] Referring to FIG. 1, the battery housing 20 is a generally cylindrical container having an opening on one side and is made of a conductive metal material. The side surface of the battery housing 20 and the bottom surface opposite the opening are generally integrally formed. That is, the battery housing 20 generally has an open upper end in its height direction and a closed lower end. The bottom surface of the battery housing 20 may have a generally flat shape. The bottom surface of the battery housing 20 may form an outer surface 20a of a closed portion. In this case, the outer surface 20a of the closed portion may function as a second electrode terminal.

[0042] The battery housing 20 accommodates the electrode assembly 10 through an opening formed on one side in the height direction thereof. The battery housing 20 can also accommodate an electrolyte through the opening. The upper end surface 25 of the battery housing 20, which forms the opening, can be folded horizontally by a crimping process after the electrolyte is injected.

[0043] The battery housing 20 may have a beading portion 21 formed at an end adjacent to an opening provided at the upper end of the battery housing 20. The battery housing 20 may further have a crimping portion formed on the beading portion 21. The beading portion 21 has a shape recessed to a predetermined depth around the outer periphery of the battery housing 20. More specifically, the beading portion 21 may have a shape recessed inward in a region between an opening formed on one side of the battery housing 20 and a receiving portion that receives the electrode assembly 10.

[0044] The beading portion 21 may provide a support surface on which at least a portion of the periphery of the current collector 30 (described later) may be placed and coupled. That is, at least a portion of the periphery of the current collector 30 of the present invention and / or the periphery of a housing cover may be placed on the upper surface of the beading portion 21. In order to stably support at least a portion of the periphery of the current collector 30, the upper surface of the beading portion 21 may have a shape that extends along a direction substantially parallel to the lower surface of the battery housing 20, i.e., along a direction substantially perpendicular to the sidewall of the battery housing 20.

[0045] 1 to 3, a current collector 30 according to an embodiment of the present invention is accommodated inside a battery housing 20 and is electrically connected to the electrode assembly 10 and the battery housing 20. That is, the current collector 30 electrically connects the electrode assembly 10 and the battery housing 20. The current collector 30 includes a support portion 31 located on one side of the electrode assembly 10, a first tab coupling portion 32 extending from the support portion 31 and coupled to the first uncoated portion 11, and a housing coupling portion 33 extending from the support portion 31 and coupled to the inner surface of the battery housing 20. The current collector 30 may include a current collector hole H2 in the center for injection of an electrolyte.

[0046] The housing coupling portion 33 may include a contact portion 33a coupled to the inner surface of the battery housing 20 and a connection portion 33b connecting the support portion 31 and the contact portion 33a. In one embodiment of the present invention, the first tab coupling portion 32 may have a width greater than that of the connection portion 33b. In another embodiment of the present invention, the contact portion 33a may have a width greater than that of the connection portion 33b.

[0047] The contact portion 33a is coupled to the inner surface of the battery housing 20. Preferably, the contact portion 33a may be coupled to the beading portion 21 of the battery housing 20. In this case, for stable contact and coupling, the beading portion 21 and the contact portion 33a may both have a shape that extends in a direction substantially parallel to the bottom surface of the battery housing 20, i.e., in a direction substantially perpendicular to the side wall of the battery housing 20.

[0048] Fig. 4 is a diagram illustrating a conventional O-ring 100. Fig. 5 is a diagram illustrating the state of the conventional O-ring 100 before it is compressed, and Fig. 6 is a diagram illustrating the state of the conventional O-ring 100 after it has been compressed.

[0049] Generally, a cylindrical battery cell undergoes an electrolyte injection process for activation after the electrode assembly 10 is inserted into the battery housing 20. During this process, an O-ring 100 is provided to prevent the electrolyte from leaking out of the battery housing 20. However, with the conventional O-ring 100, leakage of the electrolyte due to contact with the battery housing 20 and other problems resulting from a decrease in sealing performance have occurred.

[0050] For example, a conventional O-ring 100 is disposed on the contact portion 33a of the housing coupling portion 33, which is mounted on the beading portion 21. When the O-ring 100 is compressed in the height direction of the battery cell, i.e., in the winding axis direction of the electrode assembly 10, the O-ring 100 changes shape due to its elasticity. For example, as shown in FIG. 5, when the O-ring 100 is placed on the beading portion 21 and pressure is applied downward, the O-ring 100 is compressed in the vertical direction and changes shape, as shown in FIG. 6. As a result, as shown in FIG. 6, the contact area of ​​the O-ring 100 with the current collector 30 and / or the battery housing 20 is reduced. That is, after compression, the O-ring 100 is in line contact with the current collector 30 and / or the battery housing 20, preventing the battery housing 20 from being completely sealed. This significantly increases the possibility of electrolyte leakage during electrolyte injection.

[0051] More specifically, referring to FIGS. 4 to 6 , in a conventional O-ring 100, the first part 110 is not cylindrical but has a shape with extending legs. When the O-ring 100 is pressed vertically, the legs of the first part 110 are lifted upward, resulting in line contact between the current collector 30 and / or the battery housing 20 and the first part 110. This significantly increases the likelihood of the battery housing 20 being imperfectly sealed, resulting in electrolyte leakage during electrolyte injection. Specifically, when a downward force is applied by the hopper H, the bottom surface of the conventional O-ring 100 contacts the top surface of the beading portion 21 of the battery housing 20, and then the sides of the O-ring 100 are lifted to seal the sides of the battery housing 20. With this structure, the seal between the O-ring 100 and the battery housing 20 is maintained through line contact, resulting in insufficient sealing.

[0052] Therefore, the present inventors have devised an O-ring 100 structure for improving sealing performance by increasing the contact area between the battery housing 20 and the O-ring 100 compared to conventional O-rings 100. That is, the present invention relates to an O-ring 100 structure that can prevent electrolyte leakage when electrolyte is injected into a cylindrical battery cell, which will be described in detail below with reference to Figures 7 to 10.

[0053] Fig. 7 is a diagram illustrating an O-ring 100 according to one embodiment of the present invention. Fig. 8 is a diagram illustrating the state of the O-ring 100 in Fig. 7 before it is compressed, and Fig. 9 is an enlarged view of a portion of Fig. 8. Fig. 10 is a diagram illustrating the state of the O-ring 100 in Fig. 7 after it has been compressed.

[0054] Referring to FIG. 7 , the O-ring 100 includes a first part 110 and a second part 120. The O-ring 100 may further include a pressure surface 130. More specifically, the O-ring 100 may include a first part 110 that is placed on an inwardly recessed beading portion 21 of a battery housing 20, and a second part 120 that is disposed above the first part 110 and configured to cover an upper end surface 25 of the battery housing 20. The first part 110 and the second part 120 may be integrally formed. The O-ring 100 may be applied after the beading portion 21 is formed on a battery cell but before a crimping process is performed. That is, the O-ring 100 may be used after the beading portion 21 is formed on a battery cell, without the top being closed by a housing cover. That is, the O-ring 100 may be applied when the top of the battery cell is open.

[0055] The first part 110 may be configured, for example, in a substantially cylindrical shape. That is, since the first part 110 is placed on the beading portion 21 of a cylindrical battery cell, it is desirable that the first part 110 has a shape substantially similar to that of the battery housing 20. Therefore, it is desirable that the first part 110 has a substantially cylindrical shape.

[0056] This structure allows for surface contact between the O-ring 100 and the battery housing 20, thereby increasing the contact area. That is, with the above-described structure of the present invention, when the O-ring 100 is compressed in the full height direction, most of the area where the battery housing 20 and the O-ring 100 contact each other is in surface contact, which effectively prevents electrolyte from leaking outside the battery housing 20 when the electrolyte is injected.

[0057] Meanwhile, the second part 120 is provided above the first part 110 and needs to be able to cover the upper end surface 25 of the battery housing 20, so it may also be configured in a substantially cylindrical shape. More specifically, the second part 120 may have a shape that extends further horizontally from the first part 110. Therefore, the second part 120 may be configured in a cylindrical shape with a larger radius than the first part 110. However, the shape of the second part 120 is not limited to a cylindrical shape, and any shape that protrudes further radially outward than the first part 110 and can cover the upper end surface 25 of the battery housing 20 can be said to be within the scope of the present invention.

[0058] Preferably, the outer surface of the first part 110 may be configured in a cylindrical shape having a substantially constant radius. In this case, it is preferable that the distance from the center of the first part 110 to the outer surface of the first part 110 is smaller than or equal to the inner diameter of the battery housing 20. If the distance from the center of the first part 110 to the outer surface of the first part 110 is larger than the inner diameter of the battery housing 20, the first part 110 cannot be smoothly inserted into the battery housing 20.

[0059] In one embodiment of the present invention, the O-ring 100 may be configured to have elasticity. That is, the O-ring 100 may be configured to change shape under external pressure. For example, the O-ring 100 may include at least one of NBR, VMQ, FKM, and FPM.

[0060] With this configuration, when the O-ring 100 is inserted into the battery housing 20 and compressed in one direction, the shape of the O-ring 100 deforms, thereby sealing the battery housing 20. For example, when the O-ring 100 is compressed in the vertical direction, the horizontal thickness of the O-ring 100 may increase. As a result, the horizontal gap between the O-ring 100 and the battery housing 20 is filled by the deformation of the O-ring 100. As such, the elasticity of the O-ring 100 can improve sealing performance and effectively prevent electrolyte leakage. In addition, the internal pressure of the battery housing 20 can be maintained or smoothly controlled.

[0061] In another embodiment of the present invention, the O-ring 100 may include a liquid injection hole H3 that penetrates vertically through the center thereof. An electrolyte can be injected into the battery housing 20 through the liquid injection hole H3.

[0062] With the above-described structure, when the O-ring 100 is inserted into the battery housing 20 and compressed vertically, the O-ring 100 and the inner surface of the battery housing 20 come into surface contact, improving sealing performance. This prevents leakage of electrolyte when the electrolyte is injected. Furthermore, because sealing performance between the O-ring 100 and the battery housing 20 is ensured, the internal pressure of the battery housing 20 can be stably controlled.

[0063] In one aspect of the present invention, the O-ring 100 may have a groove G into which a hopper H capable of pressurizing the O-ring 100 is inserted. That is, the O-ring 100 and the hopper H may be configured to be detachable.

[0064] Referring again to FIG. 7, a hopper H capable of applying pressure to the O-ring 100 may be inserted inside the O-ring 100. The hopper H may be configured to apply pressure to at least a portion of the O-ring 100. For example, referring to FIG. 7, the hopper H may be inserted into a groove G formed inside the O-ring 100, and the hopper H may be configured to apply pressure to the pressure surface 130 of the O-ring 100. This allows the O-ring 100 to be compressed in the winding axis direction of the electrode assembly 10. More specifically, the O-ring 100 may be compressed downward.

[0065] The above-described structure facilitates replacement of the O-ring 100. Specifically, repeated compression can frequently damage the surface of the O-ring 100 that contacts the battery housing 20. In this case, the structure of the present invention as described above allows for easy replacement of the O-ring 100 alone by providing a groove G in at least a partial area of ​​the O-ring 100 to make the hopper H detachable. Furthermore, when the groove G is provided inside the O-ring 100 and the hopper H is attached inside the O-ring 100, the hopper H occupies most of the interior space of the O-ring 100, thereby reducing the cost of materials required for manufacturing the O-ring 100.

[0066] In another embodiment of the present invention, the outer surface of the first part 110 may be configured to be spaced apart from the inner surface of the battery housing 20 by a predetermined distance.

[0067] For example, referring to FIG. 8 , the outer surface of the first part 110 may be spaced apart from the inner surface of the battery housing 20 by a predetermined distance. More specifically, the outer surface of the first part 110 and the inner surface of the battery housing 20 may be spaced apart from each other by a predetermined distance in the radial direction. For example, when the outer diameter of the battery housing 20 is approximately 46 mm and the inner diameter is approximately 45 mm, the outer surface of the first part 110 may be spaced apart from the inner surface of the battery housing 20 by approximately 0.2 mm to 0.8 mm. If the distance D1 between the outer surface of the first part 110 and the inner surface of the battery housing 20 is less than approximately 0.2 mm, the process of inserting the O-ring 100 into the battery housing 20 may not be performed smoothly. In another aspect, if the distance D1 between the outer surface of the first part 110 and the inner surface of the battery housing 20 is greater than approximately 0.8 mm, surface contact for sealing may not be achieved when the O-ring 100 is compressed. Therefore, it is preferable that the outer surface of the first part 110 is spaced apart from the inner surface of the battery housing 20 by about 0.2 mm to 0.8 mm, and more preferably by about 0.5 mm to 0.7 mm. For example, the outer surface of the first part 110 may be spaced apart from the inner surface of the battery housing 20 by about 0.6 mm. Meanwhile, the present invention is not limited to the above absolute values, and relative values ​​converted in relation to the size of the battery housing 20 are also included within the scope of the present invention.

[0068] With the above-described structure, the O-ring 100 can be smoothly inserted into the battery housing 20. Furthermore, when the O-ring 100 is compressed in one direction after being inserted, the shape of the O-ring 100 is deformed and it comes into contact with the inner surface of the battery housing 20, thereby effectively sealing the battery housing 20.

[0069] In yet another embodiment of the present invention, the lower surface of the second part 120 may be configured to be spaced apart from the upper end surface 25 of the battery housing 20 by a predetermined distance.

[0070] 8, the lower surface of the second part 120 may be spaced a predetermined distance from the upper end surface 25 of the battery housing 20. More specifically, the lower surface of the second part 120 and the upper end surface 25 of the battery housing 20 may be spaced a predetermined distance in the radial direction. For example, when the outer diameter of the battery housing 20 is approximately 46 mm and the inner diameter is approximately 45 mm, the lower surface of the second part 120 may be spaced a predetermined distance from the upper end surface 25 of the battery housing 20 by approximately 0.2 mm to 0.8 mm. If the distance D2 between the lower surface of the second part 120 and the upper end surface 25 of the battery housing 20 is less than approximately 0.2 mm, repeated compression of the O-ring 100 may repeatedly cause contact between the upper end surface 25 of the battery housing 20 and the lower surface of the second part 120, increasing the likelihood of damage to the lower surface of the second part 120. In another aspect, if the distance D2 between the lower surface of the second part 120 and the upper surface 25 of the battery housing 20 is greater than about 0.8 mm, surface contact for sealing may not be achieved when the O-ring 100 is compressed. Therefore, the lower surface of the second part 120 is preferably spaced apart from the upper surface 25 of the battery housing 20 by about 0.2 mm to 0.8 mm, and more preferably by about 0.5 mm to 0.7 mm. For example, the lower surface of the second part 120 may be spaced apart from the upper surface 25 of the battery housing 20 by about 0.6 mm. However, the present invention is not limited to the above absolute values, and relative values ​​converted in relation to the size of the battery housing 20 are also within the scope of the present invention.

[0071] According to the above-described structure, when the O-ring 100 is compressed, the shape of the O-ring 100 is deformed, causing the second part 120 to abut against the upper end surface 25 of the battery housing 20, thereby further sealing the battery housing 20.

[0072] In yet another embodiment of the present invention, the outer diameter of the second part 120 can match the outer diameter of the battery housing 20 .

[0073] 9, the outer surface of the battery housing 20 and the outer surface of the second part 120 may be configured to have approximately the same diameter. With this configuration, even if the outer diameters of the battery housing 20 and the O-ring 100 are similar and the upper end surface 25 of the battery housing 20 and the lower surface of the second part 120 repeatedly come into contact with each other, the end of the O-ring 100 may deform, reducing the possibility of damage to the lower surface of the second part 120.

[0074] For example, in a conventional O-ring 100, the outer diameter of the second part 120 is larger than the outer diameter of the battery housing 20, and therefore repeated contact between the upper end surface 25 of the battery housing 20 and the lower surface of the second part 120 is likely to cause the point of the second part 120 that abuts against the upper end surface 25 of the battery housing 20 to be indented inward and damaged. However, according to the above-described structure of the present invention, the outer diameters of the battery housing 20 and the O-ring 100 are similar, so even if the point of the second part 120 that abuts against the upper end surface 25 of the battery housing 20 is deformed upward, the phenomenon of indenting inward can be prevented.

[0075] In one embodiment of the present invention, the O-ring 100 may include a pressure surface 130 provided in at least a partial region of the O-ring 100 and configured to be pressed downward by the hopper H. For example, the O-ring 100 may include a pressure surface 130 provided inside or outside the O-ring 100 and configured to be pressed downward by the hopper H.

[0076] For example, referring to FIG. 7 , the pressure surface 130 may be configured to pressurize the O-ring 100 downward. For example, the upward surface of the groove G formed inside the O-ring 100 may correspond to the pressure surface 130. That is, the upward surface of the groove G formed inside the O-ring 100 abuts against the lower surface of a hopper H, and the surface pressed by the lower surface of the hopper H may correspond to the pressure surface 130 of the O-ring 100. Alternatively, the upper surface of the O-ring 100 shown in FIG. 7 may also correspond to the pressure surface 130. For example, the hopper H may be insertable into the groove G formed inside the O-ring 100, but may also be shaped to pressurize the upper surface of the O-ring 100. In the O-ring 100 shown in the embodiment of FIG. 7 , the upward surface of the groove G formed inside the O-ring 100 and the upper surface of the O-ring 100 may correspond to the pressure surface 130.

[0077] In another aspect of the present invention, when the pressure surface 130 is pressed downward, the first part 110 may be configured to be compressed in the vertical direction and increase in width in the radial direction. That is, when pressure acts from the outside of the battery housing 20 toward the beading portion 21 of the battery housing 20, the first part 110 may be configured to come into contact with the inner surface of the battery housing 20.

[0078] To reliably prevent leakage, it is desirable that the contact pressure between the outer surface of the first part 110 and the inner surface of the battery housing 20 be greater than the electrolyte injection pressure. For example, if the electrolyte injection pressure is approximately 8 bar, the seal can be maintained only if the contact pressure between the outer surface of the first part 110 and the inner surface of the battery housing 20 is greater than approximately 8 bar.

[0079] In still another aspect of the present invention, when the pressure surface 130 is pressed downward, the second part 120 may be configured to move downward and contact the upper end surface 25 of the battery housing 20. That is, when pressure acts from the outside of the battery housing 20 toward the beading portion 21 of the battery housing 20, the second part 120 may be configured to contact the upper end surface 25 of the battery housing 20.

[0080] With the above configuration, a primary seal is achieved by sealing between the outer surface of the first part 110 and the inner surface of the battery housing 20, and a secondary seal is achieved between the lower surface of the second part 120 and the upper end surface 25 of the battery housing 20.

[0081] To reliably prevent leakage, it is desirable that the contact pressure between the lower surface of the second part 120 and the upper surface 25 of the battery housing 20 be greater than the electrolyte injection pressure. For example, if the electrolyte injection pressure is approximately 8 bar, a secondary sealing effect can be achieved if the contact pressure between the lower surface of the second part 120 and the upper surface 25 of the battery housing 20 is greater than approximately 8 bar.

[0082] That is, with the above-described configuration, when pressure acts from the outside of the battery housing 20 toward the beading portion 21 of the battery housing 20, the O-ring 100 can be configured to isolate the outside from the inside of the battery housing 20. This can improve the sealing performance of the battery housing 20 and effectively prevent leakage of electrolyte. In addition, the internal pressure of the battery housing 20 can be maintained or smoothly controlled.

[0083] FIG. 11 is a diagram illustrating an O-ring 100 according to another embodiment of the present invention.

[0084] The O-ring 100 of this embodiment is similar to the O-ring 100 of the previously described embodiment, and therefore, redundant explanations of configurations that are substantially identical or similar to those of the previously described embodiment will be omitted, and the following description will focus on the differences from the previously described embodiment.

[0085] 11 , the second part 120 of the O-ring 100 may further include an extended cover portion 121. The extended cover portion 121 may extend downward from the second part 120 and may be configured to cover the outer surface of the top end surface 25 of the battery housing 20. The extended cover portion 121 may be configured to contact the outer surface of the battery housing 20. An end surface of the extended cover portion 121 may be configured parallel to the horizontal direction.

[0086] With the above-described configuration, in addition to a primary seal between the outer surface of the first part 110 and the inner surface of the battery housing 20 and a secondary seal between the bottom surface of the second part 120 and the top surface 25 of the battery housing 20, a tertiary seal can be achieved between the inner surface of the extended cover portion 121 and the outer surface of the battery housing 20. In other words, the sealing force can be further ensured. In this case, it is desirable that the contact pressure between the inner surface of the extended cover portion 121 and the outer surface of the battery housing 20 be greater than the injection pressure of the electrolyte.

[0087] FIG. 12 is a diagram illustrating an O-ring 100 according to still another embodiment of the present invention.

[0088] The O-ring 100 of this embodiment is similar to the O-ring 100 of the previously described embodiment, and therefore, redundant explanations of configurations that are substantially identical or similar to those of the previously described embodiment will be omitted, and the following description will focus on the differences from the previously described embodiment.

[0089] 12, the O-ring 100 may include a lower surface 111. In this case, the lower surface 111 may be the lower surface 111 of the first part 110. That is, the lower surface of the first part 110 may correspond to the lower surface 111 of the O-ring 100. Referring again to FIG. 7, the lower surface 111 of the O-ring 100 is configured to contact the beading portion 21 and / or the current collector 30. More specifically, the lower surface 111 of the O-ring 100 may be configured to contact the upper surface of the beading portion 21 and / or the contact portion 33a of the housing coupling portion 33 of the current collector 30. That is, the contact portion 33a of the current collector 30 is placed on the upper surface of the beading portion 21. Since the current collector 30 has a predetermined thickness, when the O-ring 100 is placed on the beading portion 21 and / or the current collector 30, a small gap may exist between the O-ring 100 and the upper surface of the beading portion 21. The size of the small gap may be the same as the thickness of the current collector 30. That is, a small gap may exist between the O-ring 100 and the beading portion 21, which may cause electrolyte leakage through the gap. Meanwhile, since the O-ring 100 has elasticity, the size of the gap may decrease when the O-ring 100 is pressed in the vertical direction. However, since the gap may not completely disappear, it is preferable that the lower surface of the O-ring 100 be provided with at least one lower groove 113 to match the shape of the contact portion 33a of the current collector 30.

[0090] More specifically, referring to FIG. 12 , the thickness of the first part 110 may alternately increase and decrease in the circumferential direction. For example, grooves G may be formed at predetermined intervals in the circumferential direction on the lower surface of the first part 110. Preferably, the grooves G may be configured to match the shape of the current collector 30. That is, the lower surface of the first part 110 may be formed with at least one lower groove 113 recessed upward. For example, in one embodiment, if the current collector 30 has four contact portions 33a, the lower surface of the O-ring 100 may also have four lower grooves 113. In this case, the shapes of the contact portions 33a and the lower grooves 113 of the O-ring 100 may preferably match each other. For example, the contact portions 33a of the current collector 30 may have an arc shape that at least a portion thereof extends in the circumferential direction along the beading portion 21 of the battery housing 20. As a result, the circumferential extension length of the contact portion 33a may be longer than the width of the connecting portion 33b. In another embodiment, the contact portion 33a may have an arc shape extending in opposite directions along the circumferential direction on the beading portion 21 from the intersection of the connecting portion 33b and the contact portion 33a. However, the number or shape of the contact portions 33a of the current collector 30 and the number or shape of the lower grooves 113 of the O-ring 100 are not limited to this embodiment. In other words, any shape that matches the shape of the contact portion 33a and the shape of the lower groove 113 of the O-ring 100 is within the scope of the present invention.

[0091] The above-described configuration can prevent a gap from forming between the O-ring 100 and the beading portion 21. That is, the O-ring 100 can more effectively seal the battery housing 20. This further reduces the possibility of electrolyte leakage. In addition, an environment can be created in which the internal pressure of the battery housing 20 can be maintained constant.

[0092] FIG. 13 is a diagram illustrating an O-ring 100 according to still another embodiment of the present invention.

[0093] The O-ring 100 of this embodiment is similar to the O-ring 100 of the previously described embodiment, and therefore, redundant explanations of configurations that are substantially identical or similar to those of the previously described embodiment will be omitted, and the following description will focus on the differences from the previously described embodiment.

[0094] Referring to FIG. 13 , the O-ring 100 does not include a groove G inside. The O-ring 100 may include a groove G outside. For example, the O-ring 100 shown in FIG. 13 has only a liquid injection hole H3 for liquid injection in the center, and does not have a groove G for inserting a hopper H. Instead, a groove G into which a hopper H can be inserted may be formed on the outer surface of the O-ring 100. In this manner, the groove G may be formed on the outside or inside of the O-ring 100, and depending on the shape of the groove G, the hopper H may also be coupled to the outside or inside of the O-ring 100. In other words, the location where the groove G is formed is not limited, and any configuration in which a hopper H is attached to the groove G and the hopper H can compress the O-ring 100 is within the scope of the present invention.

[0095] Although the present invention has been described above using limited embodiments and drawings, it goes without saying that the present invention is not limited thereto, and that various modifications and variations can be made by a person having ordinary knowledge in the technical field to which the present invention pertains within the technical spirit of the present invention and the equivalent scope of the claims set forth below. [Explanation of symbols]

[0096] 1 battery cell 7 See below 10 Electrode assembly 11 First plain section 12 Second plain section 20 Battery housing 20a outer surface 21 Beading section 25 Top surface 30 Current collector 31 Support part 32 First tab joint 33 Housing joint 33a Contact part 33b Connection 50 terminals 60 Second current collector 100 O-rings 110 Part 1 111 Lower surface 113 Lower Groove 120 Part 2 121 Extended cover part 130 Pressure Surface D1 Distance D2 distance G groove H Hopper H1 Winding center hole H2 collector hole H3 liquid injection hole O prevention

Claims

1. a first part of the battery housing that rests on the inwardly recessed beading; a second part provided above the first part and configured to cover an upper end surface of the battery housing.

2. The O-ring of claim 1 , wherein the first part is cylindrically configured.

3. The O-ring of claim 1 , wherein the O-ring is resilient.

4. The O-ring is The O-ring of claim 1 , comprising at least one of NBR, VMQ, FKM, and FPM.

5. The O-ring according to claim 1 , wherein the O-ring includes a liquid injection hole that penetrates the center of the O-ring in the vertical direction.

6. The O-ring is The O-ring according to any one of claims 1 to 5, having a groove into which a hopper capable of pressurizing the O-ring is inserted.

7. The O-ring of claim 1 , wherein the outer surface of the first part is configured to be spaced a predetermined distance from the inner surface of the battery housing.

8. 2. The O-ring of claim 1, wherein the outer surface of the first part is configured to be spaced from the inner surface of the battery housing by 0.2 mm to 0.8 mm.

9. The O-ring according to claim 1 , wherein the lower surface of the second part is configured to be spaced apart from the upper end surface of the battery housing by a predetermined distance.

10. The O-ring is The O-ring of claim 6 , further comprising a pressure surface provided on the interior or exterior of the O-ring and configured to be pressed downward by the hopper.

11. The O-ring according to claim 10 , wherein the first part is configured to be compressed in the vertical direction and increase in width in the radial direction when the pressure surface is pressed downward.

12. The O-ring according to claim 10 , wherein the second part is configured to move downward and contact an upper end surface of the battery housing when the pressure surface is pressed downward.

13. 2. The O-ring according to claim 1, wherein the O-ring is configured to isolate the outside and the inside of the battery housing when pressure acts from the outside of the battery housing toward the beading portion of the battery housing.

14. The O-ring of claim 1 , wherein the thickness of the first part alternately increases and decreases along the circumferential direction.

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