O-ring member for electrolyte injection, and electrolyte injection apparatus including same
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- LG ENERGY SOLUTION LTD
- Filing Date
- 2025-12-12
- Publication Date
- 2026-07-30
Smart Images
Figure KR2025021514_30072026_PF_FP_ABST
Abstract
Description
O-ring member for electrolyte injection, and electrolyte injection device including the same
[0001] The present invention relates to an O-ring member for injecting an electrolyte, and more specifically, to an O-ring member for injecting an electrolyte capable of improving the sealing performance of a folded area provided on the upper surface of a beading portion of a battery housing, and an electrolyte injection device 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] Lithium secondary batteries are classified according to the shape of the battery case into prismatic and cylindrical secondary batteries, in which the electrode assembly is housed in a metal battery can (battery housing), and pouch-type secondary batteries, in which the electrode assembly is housed in a pouch case made of an aluminum laminate sheet. A cylindrical battery cell comprises an electrode assembly with a jelly roll structure containing a positive electrode, a negative electrode, and a separator, and a battery housing that accommodates the electrode assembly. An electrolyte is filled inside the battery housing to facilitate chemical reactions at the electrodes of the electrode assembly through the movement of ions.
[0004] An electrolyte injection device is used to fill the battery housing with electrolyte. The electrolyte injection device may include an injection hopper for injecting the electrolyte. The injection speed of the electrolyte is a factor that affects the process efficiency and manufacturing costs of the battery cell. The faster the electrolyte is injected into the battery housing, the higher the manufacturing process efficiency of the battery cell and the lower the manufacturing costs can be.
[0005] There is a risk of electrolyte leakage during the high-speed injection process through the injection hopper, and such leakage can cause various problems. For instance, leaked electrolyte may contaminate or damage the working environment, injection equipment, or electronic components, leading to increased maintenance costs. Furthermore, exposure to the volatile and chemically reactive electrolyte poses safety risks to workers and increases the risk of fire. In addition, failure to inject the correct amount of electrolyte into the battery housing can hinder proper internal chemical reactions within the electrode assembly, potentially resulting in a degradation of battery performance and quality.
[0006] To prevent leakage of the electrolyte during the electrolyte injection process, an O-ring may be provided at the bottom of the injection hopper. The O-ring seals the space between the injection hopper and the inner surface of the battery housing to maintain airtightness, thereby preventing the electrolyte from leaking through the gap between the injection hopper and the inner surface of the battery housing. Additionally, the O-ring can also maintain a constant pressure during the electrolyte injection process, thereby ensuring that the electrolyte is injected in an accurate amount.
[0007] Meanwhile, the battery housing may be provided with a beading portion that provides a support surface for a battery cap to be seated thereon, which seals an opening provided at the top of the battery housing after the electrolyte is injected. The beading portion may be formed by pressing the outer circumference of the top of the battery housing inward so as to protrude inward. A portion of the negative electrode current collector (periphery) may be seated and / or coupled to the beading portion.
[0008] Accordingly, a step difference may occur between the upper surface of the beading portion and the upper surface of the negative electrode current collector, and due to this step difference, a fine gap may form between the O-ring and the upper surface of the beading portion, which may lead to a problem where the performance of preventing electrolyte leakage is degraded. In addition, when injecting the electrolyte using a hole injection method, it may be difficult to effectively seal the step difference according to the thickness of the negative electrode current collector plate by sealing the opening of the battery housing with an O-ring alone. 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.
[0009] The present invention is to provide an O-ring member for injecting an electrolyte that can improve the sealing performance of a folded area provided on the upper surface of a beading portion of a battery housing, and an electrolyte injection device including the same.
[0010] In addition, the present invention aims to provide an O-ring member for injecting an electrolyte that can improve airtightness by effectively sealing the step portion between a current collector placed on a beading portion of a battery housing and the beading portion, and an electrolyte injection device including the same.
[0011] In addition, the present invention aims to provide an O-ring member for electrolyte injection capable of suppressing and mitigating electrolyte leakage and reducing the amount of electrolyte remaining in the beading portion by designing the radius of curvature of the sealing portion of the O-ring member to an appropriate range, and an electrolyte injection device including the same.
[0012] 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.
[0013] An O-ring member for injecting an electrolyte according to an embodiment of the present invention is an O-ring member for injecting an electrolyte into a cylindrical battery housing constituting a battery cell, for sealing the area around a beading portion into which the battery housing is drawn inward during the process of injecting an electrolyte into the battery cell, and comprises: a cylindrical O-ring body having a groove portion at the top into which an injection hopper for injecting the electrolyte can be fitted, and an electrolyte injection passage formed vertically through the center through which the electrolyte can flow; and a sealing portion formed integrally with the O-ring body and having a circular ring-shaped protrusion that protrudes in a curved shape having a circular cross-section in an inclined direction toward the downward and outward along the lower circumference of the O-ring body.
[0014] The above O-ring body may be configured to transmit downward pressure applied through the injection hopper to the sealing part while the sealing part is seated on the beading part, thereby pressing the protrusion downward.
[0015] The above protrusion may be configured to pressure seal a bent area provided along the upper perimeter of the beading portion by expanding outward in the radial direction due to the reaction force of the pressure applied to the upper surface of the beading portion.
[0016] The above-mentioned bending region is a curved region where the side wall of the battery housing and the upper surface of the beading portion intersect, and the sealing portion can be in close contact with the upper surface of the beading portion and the inner surface of the side wall of the battery housing within the bending region.
[0017] According to one embodiment, the protrusion may have a radius of curvature of 0.6 mm or more and less than 2 mm.
[0018] According to one embodiment, the bending area of the beading portion may have a radius of curvature within the range of 0.3 mm to 0.5 mm, and the protrusion may have a radius of curvature within the range of 1.5 mm to 1.9 mm.
[0019] The outer surface of the O-ring body and the sealing part may be formed as an inclined surface in which the outer diameter expands downward while forming a constant angle of inclination from the area below the groove part.
[0020] The O-ring body and the sealing part may have an entire area extending from the outer surface of the O-ring body and the sealing part to the lower surface of the sealing part and the bottom surface of the O-ring body connected only by flat and curved surfaces without corners.
[0021] The above protrusion may be configured to seal the step difference between a part of the negative current collector disposed on the upper surface of the beading portion and the beading portion.
[0022] According to another embodiment of the present invention, an electrolyte injection device is provided comprising: an O-ring member for electrolyte injection; and an electrolyte injection hopper disposed on the O-ring member for electrolyte injection.
[0023] According to an embodiment of the present invention, an O-ring member for injecting an electrolyte that can improve the sealing performance of a folded area provided on the upper surface of a beading portion of a battery housing, and an electrolyte injection device including the same are provided.
[0024] In addition, according to an embodiment of the present invention, an O-ring member for injecting an electrolyte and an electrolyte injection device including the same are provided, which can effectively seal the step difference between a current collector placed on a beading portion of a battery housing and the beading portion to improve airtightness performance.
[0025] In addition, according to an embodiment of the present invention, by designing the radius of curvature of the sealing portion of the O-ring member to an appropriate range, leakage of the electrolyte can be suppressed and mitigated, and at the same time, the amount of electrolyte remaining in the beading portion can be reduced.
[0026] 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.
[0027] FIG. 1 is a cross-sectional view showing an electrolyte injection device according to an embodiment of the present invention.
[0028] FIG. 2 is a perspective view showing a battery cell that is the target of electrolyte injection of an electrolyte injection device according to an embodiment of the present invention.
[0029] Figure 3 is a cross-sectional perspective view of the battery cell shown in Figure 2.
[0030] Figure 4 is a cross-sectional view of the battery cell shown in Figure 2.
[0031] FIG. 5 is a perspective view showing an O-ring member for injecting an electrolyte according to an embodiment of the present invention.
[0032] FIG. 6 is a cross-sectional view showing an O-ring member for electrolyte injection according to an embodiment of the present invention.
[0033] FIG. 7 is a drawing for explaining the function of an O-ring member for electrolyte injection according to an embodiment of the present invention.
[0034] Figure 8 is an enlarged view of section 'A' of Figure 7.
[0035] FIGS. 9a, FIGS. 9b, and FIGS. 10 are drawings showing experimental results illustrating the performance of an O-ring member for electrolyte injection according to an embodiment of the present invention.
[0036] FIG. 9a is a cross-sectional view showing an O-ring member according to a comparative example that is compared with the performance of an O-ring member for electrolyte injection according to an embodiment of the present invention.
[0037] Figure 9b is a simulation result showing the contact distribution between the O-ring member and the beading portion of the battery housing according to the comparative example shown in Figure 9a.
[0038] Figure 10 is a simulation result showing the contact distribution between the O-ring member for electrolyte injection and the beading portion of the battery housing according to an embodiment of the present invention.
[0039] 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.
[0040] 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.
[0041] An electrolyte injection device according to an embodiment of the present invention includes an O-ring member for electrolyte injection. The O-ring member for electrolyte injection according to an embodiment of the present invention may include a cylindrical O-ring body having an electrolyte injection passage, and a sealing part having a circular ring-shaped protrusion formed integrally with the O-ring body and protruding in a curved shape having a circular cross-section (more specifically, an arc-shaped cross-section forming part of a circle) in an inclined direction toward the downward and outward along the lower circumference of the O-ring body.
[0042] To improve the sealing performance of the step portion between the upper surface of the beading portion and the current collector placed on the upper surface of the beading portion, the protrusion of the sealing portion may have a radius of curvature of 0.1 mm or more and less than 2 mm, and more preferably may have a radius of curvature of 1.5 mm to 1.9 mm. To improve sealing performance, the outer surface of the O-ring body and the sealing portion is formed as an inclined surface with an outer diameter that expands downward while forming a constant angle of inclination, and the entire area from the outer surface of the O-ring body and the sealing portion to the lower surface of the sealing portion and the bottom surface of the O-ring body may be connected only by flat and curved surfaces without corners.
[0043] According to the O-ring member according to an embodiment of the present invention, the sealing performance of the bent area provided on the upper surface of the beading portion of the battery housing can be improved, and the airtightness performance can be improved by effectively sealing the step difference between the current collector placed on the beading portion of the battery housing and the beading portion. In addition, by designing the radius of curvature of the sealing portion of the O-ring member to be within an appropriate range, leakage of the electrolyte can be suppressed and mitigated, and at the same time, the amount of electrolyte remaining in the beading portion can be reduced.
[0044] FIG. 1 is a cross-sectional view showing an electrolyte injection device according to an embodiment of the present invention. Referring to FIG. 1, the electrolyte injection device according to an embodiment of the present invention is a device for supplying and injecting an electrolyte into a battery housing (20), and may be configured to inject the electrolyte through an opening formed at the upper end of the battery housing (20) constituting a battery cell (1). The battery cell (1) to which the electrolyte is to be injected may be a cylindrical battery cell.
[0045] In one embodiment, the electrolyte injection device may include an O-ring member for electrolyte injection (hereinafter abbreviated as 'O-ring member') (100), an injection hopper (200), and a sealing member (300). The injection hopper (200) may have a hollow structure to allow the electrolyte supplied by the electrolyte supply device to pass through. The injection hopper (200) may function as a connector connecting the electrolyte supply device and the battery housing (20) constituting the battery cell (1) during electrolyte injection. The injection hopper (200) may include a metal material to ensure rigidity. However, the material of the injection hopper (200) is not limited thereto, and various materials having appropriate rigidity and chemical resistance to the electrolyte passing through the interior may be applied.
[0046] The O-ring member (100) may be configured to be coupled to the lower portion of the liquid injection hopper (200) to seal the beading portion (21) of the battery housing (20). The O-ring member (100) may include a flexible material to prevent electrolyte leakage between the coupling portion of the liquid injection hopper (200) and the O-ring member (100) and between the O-ring member (100) and the beading portion (21) of the battery housing (20). The O-ring member (100) may include, for example, a rubber material or a polymer resin. The O-ring member (100) may have a hollow structure so that its internal space communicates with the internal space of the liquid injection hopper (200). The O-ring member (100) may be provided as a roughly cylindrical member with a hollow center.
[0047] The sealing member (300) may be coupled to the upper part of the liquid injection hopper (200) and configured to connect the liquid injection hopper (200) and the electrolyte supply device. The sealing member (300) can prevent the electrolyte from leaking at the connection point between the electrolyte supply device and the liquid injection hopper (200). The sealing member (300) may include a flexible material (e.g., rubber material, polymer resin, etc.) to prevent the electrolyte from leaking at the connection point between the liquid injection hopper (200) and the sealing member (300) and at the contact point between the sealing member (300) and the electrolyte supply device.
[0048] Hereinafter, a battery cell is described first, and an O-ring member for injecting electrolyte for sealing the beading portion of the battery housing constituting the battery cell is described later. FIG. 2 is a perspective view showing a battery cell that is the target for electrolyte injection of an electrolyte injection device according to an embodiment of the present invention. FIG. 3 is a cross-sectional perspective view of the battery cell shown in FIG. 2. FIG. 4 is a cross-sectional view of the battery cell shown in FIG. 2. FIG. 4 shows a battery cell in a state where the upper opening of the battery cell (1) is sealed with a battery cap (40) after the electrolyte has been injected into the battery cell (1).
[0049] Referring to FIGS. 2 to 4, the battery cell (1) may include an electrode assembly (10), a battery housing (20), a first current collector (30), a battery cap (40), a sealing gasket (50), a second current collector (60), a rivet (70), and an insulating part (80). The battery cell (1) is not necessarily limited to the shape of the battery cell shown in FIGS. 2 to 4, and the electrolyte injection device according to an embodiment of the present invention may be applied to inject electrolyte into a battery cell having a shape different from the shown shape. Components such as a busbar for electrical connection, a cooling unit, and a power terminal are omitted from the illustration in FIGS. 2 to 4.
[0050] The 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 without limitation to have a winding structure well known in the art of the present invention.
[0051] The first electrode may include a first electrode current collector and a first electrode active material applied on one or both sides of the first electrode current collector. A non-coated portion in which the first electrode active material is not applied may be provided 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). That is, the first electrode may include a first non-coated portion (11) that is not coated with active material at one long end along the winding direction and is exposed to the outside of the separator. The first non-coated portion (11) may function as a first electrode tab. The first non-coated portion (11) may be provided at the upper end with respect to the height direction of the electrode assembly (10) housed within the battery housing (20). The first non-coated portion (11) may be, for example, a negative electrode tab.
[0052] The second electrode may include 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-coated portion at the other end where the second electrode active material is not applied. That is, the second electrode may include a second non-coated portion (12) that is not coated with active material at the other long end along the winding direction and is exposed to the outside of the separator. The second non-coated portion (12) may function as a second electrode tab. The second non-coated portion (12) may be provided at the bottom based on the height direction of the electrode assembly (10) housed within the battery housing (20). The second non-coated portion (12) may be, for example, a positive electrode tab.
[0053] The battery housing (20) may be a roughly cylindrical receptacle with an opening (20a) formed on one side. The battery housing (20) may be provided with a conductive metal material. The battery housing (20) may be configured to accommodate an electrode assembly (10) of a 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 configured to accommodate an electrode assembly (10) and an electrolyte through an opening (20a) formed on its upper side.
[0054] 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) may have 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).
[0055] The beading portion (21) may provide a support surface on which a sealing gasket (50) and a battery cap (40) can be seated. Additionally, the beading portion (21) may provide a support surface on which at least a portion of the edge circumference of a first current collector (e.g., a negative current collector) (30) can be seated and joined. At least a portion of the edge circumference of the current collector (30), at least a portion of the edge circumference of the sealing gasket (50), and at least a portion of the edge circumference of the battery cap (40) can be seated on the upper surface of the beading portion (21). The beading portion (21) may 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).
[0056] In order to stably support the first 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).
[0057] 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) can be fixed on the beading portion (21) by the crimping portion (22). The crimping portion (22) may have a shape that extends inward in the radial direction (centripetal direction) of the battery cell (1) from the upper perimeter of the battery housing (20). 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.
[0058] 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), and can cover the opening (20a) of the battery housing (20).
[0059] The first current collector (30) can be accommodated inside the battery housing (20). The first current collector (30) can be made of a conductive metal material and can be electrically connected to the electrode assembly (10). The first 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 first current collector (30) may have a support portion (31), a tab coupling portion (32), and a housing coupling portion (33).
[0060] The support portion (31) and the tab connecting portion (32) of the first 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 first current collector (30) may be located below the lower surface of the beading portion (21).
[0061] A through hole (not shown) may be formed in the first 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 first 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 first 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.
[0062] 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). According to an embodiment of the present invention, the winding hole (H1) and the current collector hole (H2) communicating with each other do not need to function as a passage for a welding rod or laser beam for welding between the electrode terminal of the electrode assembly (10) and the current collector, or between the electrode terminal and a lead tab (not shown). Therefore, the energy density of the electrode assembly (10) can be increased by reducing the size of the winding hole (H1) and the current collector hole (H2).
[0063] 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, thereby reducing liquid injection performance. 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).
[0064] The housing coupling portion (33) may be connected to the inner surface of the battery housing (20) by extending from the support portion (31) to a periphery area. The housing coupling portion (33) may be electrically connected to the inner surface of the battery housing (20) by extending from the support portion (31). For example, the housing coupling portion (33) may be connected to the upper surface of the beading portion (21) on the inner surface of the battery housing (20).
[0065] The inner diameter of the battery housing (20) in the area where the beading portion (21) is formed may 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 first current collector (30), for example, laser welding, ultrasonic welding, or spot welding may be applied.
[0066] 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).
[0067] 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.
[0068] 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 securing force and the sealing performance of the battery housing (20), a sealing gasket (50) may be interposed between the battery housing (20) and the battery cap (40), and between the current collector (30) and the battery cap (40). The sealing gasket (50) can seal the top opening of the battery housing (20) between the battery cap (40) and the crimping portion (22) 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.
[0069] A current collector (30) may 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) may be secured by the bending of a crimping portion (22) extending upward from the beading portion (21). The sealing gasket (50) is provided to surround the battery cap (40) to seal the space between the battery cap (40) and the battery housing (20). The sealing gasket (50) may serve to maintain airtightness between the battery housing (20) and the battery cap (40).
[0070] Hereinafter, an O-ring member for injecting electrolyte is described, which can prevent leakage of electrolyte during the process of injecting electrolyte into the battery cell (1) described above and reduce the amount of electrolyte remaining on the beading portion (21) of the battery housing (20). FIG. 5 is a perspective view showing an O-ring member for injecting electrolyte according to an embodiment of the present invention. FIG. 6 is a cross-sectional view showing an O-ring member for injecting electrolyte according to an embodiment of the present invention. FIG. 7 is a drawing for explaining the function of an O-ring member for injecting electrolyte according to an embodiment of the present invention. FIG. 8 is an enlarged view of portion 'A' of FIG. 7.
[0071] Referring to FIGS. 1 to 8, the O-ring member (100) may include a cylindrical O-ring body (110) and a sealing portion (120) provided at the bottom of the O-ring body (110). The O-ring body (110) and the sealing portion (120) may be a single O-ring formed integrally, but to aid in understanding the invention, the upper and lower regions of the O-ring member (100) will be described by dividing them into the O-ring body (110) and the sealing portion (120) according to their location, function, and shape.
[0072] The O-ring body (110) provided in the upper region of the O-ring member (100) forms a roughly cylindrical shape and can serve to support the sealing portion (120) at the bottom. The sealing portion (120) provided in the lower region of the O-ring member (100) can be provided in a structure that can effectively seal the bent area on the outer edge of the upper surface of the beading portion (21) in the stepped portion between the beading portion (21) of the battery housing (20) and the current collector (30). The bent area of the beading portion (21) may be a curved area where the crimping portion (22) and the upper surface of the beading portion (21) meet.
[0073] First, regarding the O-ring body (110), the O-ring body (110) may be provided with a groove portion (113, 114, 115, 116) on the upper side into which an injection hopper (200) for injecting electrolyte may be fitted. The groove portion (113, 114, 115, 116) may be provided with a groove portion (insertion groove) into which a coupling projection provided at the lower end of the injection hopper (200) is inserted, and a locking projection portion (locking projection portion) that supports the injection hopper (200) to maintain the state in which the coupling projection is inserted therein.
[0074] To describe the groove portions (113, 114, 115, 116) in more detail, the groove portions (113, 114, 115, 116) may include a locking projection portion (113) and an insertion groove (115). The locking projection portion (113) may be formed to protrude inward along the circumference of the upper opening of the O-ring body (110). The locking projection portion (113) may have an inclined inner surface (114) in which the inner diameter is reduced downward to induce insertion of a coupling projection provided at the lower end of the injection hopper (200).
[0075] The insertion groove (115) may be provided at the lower part of the locking projection (113) with the same shape as the coupling projection of the injection hopper (200). The insertion groove (115) may be formed as an inclined surface (116) in which the inner diameter of the lower side thereof is reduced downward. Accordingly, it can induce the insertion of the wedge-shaped coupling projection provided at the lower part of the injection hopper (200) and support the coupling projection so that it remains in a stably coupled state without detaching.
[0076] The O-ring body (110) may have an electrolyte injection passage (117) formed through it in the upper and lower directions through which the electrolyte can flow in the center. At least a portion of the outer surface (112) of the O-ring body (110) may be formed as an inclined surface inclined in the upper and lower directions. This is to ensure that the sealing portion (120), which will be described later, is pressed downward through the O-ring body (110) and is pressed in close contact toward a folded area provided along the circumferential direction on the upper surface of the beading portion (21) of the battery housing (20).
[0077] The outer surface portion (112) forming the outer surface of the lower and middle regions of the O-ring body (110) can be formed as an inclined surface so as to protrude by a set protrusion distance (D1) from the upper outer surface portion (111) forming the outer surface of the upper part of the O-ring body (110) where the groove portion is provided.
[0078] The outer surface portions (112, 122) of the O-ring body (110) and the sealing portion (120) can be formed as inclined surfaces with an outer diameter that expands downward while forming a constant angle of inclination (θ1) from the area below the groove portions (113, 114, 115, 116). That is, the outer surface portions (112, 122) of the O-ring body (110) and the sealing portion (120) can be formed as inclined surfaces that are narrow at the top and wide at the bottom.
[0079] Accordingly, when the O-ring member (100) is inserted through the opening of the battery housing (20), the lower region of the O-ring member (100), which forms a circular ring shape, mainly comes into contact with the inner surface of the battery housing (20), and accordingly, the O-ring member (100) can be smoothly inserted by the sealing portion (120) provided in the lower region of the O-ring member (100).
[0080] When the O-ring member (100) is pressed downward on the beading portion (21) of the battery housing (20), the sealing portion (120) can be elastically deformed by an appropriate pressure. At this time, in order for the sealing portion (120) to effectively seal the bent area of the beading portion (21), it may be preferable that the inclination angle (θ1) of the outer surface portion (112) of the O-ring body (110) be designed to be within the range of 5° to 30° with respect to the vertical direction, and the horizontal protrusion distance (D1) from the upper outer surface of the O-ring body (110) be designed to be within the range of 1 mm to 5 mm.
[0081] This is because by securing the angle of inclination (θ1) of the outer surface portion (112) of the O-ring body (110) at an angle of about 5° or more with respect to the vertical direction, the O-ring member (100) can be smoothly inserted into the battery housing (20), and also sufficiently transmit the force to expand the seal portion (120) radially outward when the O-ring member (100) is pressed.
[0082] Additionally, if the angle of inclination (θ1) of the outer surface (112) of the O-ring body (110) exceeds 30° in the vertical direction, the area of the upper part of the O-ring body (110) is reduced, which can excessively restrict the flow path area through which the electrolyte can be supplied, and consequently, the injection speed of the electrolyte is significantly slowed down, which can increase the process efficiency and process cost of the electrolyte injection process.
[0083] Similarly, if the horizontal protrusion distance (D1) from the upper outer surface of the O-ring body (110) is less than 1 mm, it becomes difficult to sufficiently transmit the force that expands the sealing portion (120) radially outward when the O-ring member (100) is pressed, and if the O-ring member (100) is inserted at a slight angle, it may get caught in the inner diameter of the battery housing (20) and may not be easily inserted.
[0084] Conversely, when the horizontal protrusion distance (D1) from the outer surface of the upper part of the O-ring body (110) exceeds 5 mm, the area of the upper part of the O-ring body (110) is reduced, and the flow path area through which the electrolyte can be supplied may be limited, and accordingly, the injection speed of the electrolyte may be slowed down, thereby increasing the process efficiency and process cost of the electrolyte injection process.
[0085] The sealing portion (120) may be provided with a circular ring-shaped protrusion (120a) provided on the lower surface of the O-ring body (110). The protrusion (120a) may be formed integrally with the O-ring body (110). The protrusion (120a) may be formed to protrude in a curved shape with a circular cross section in an inclined direction toward the lower and outer sides along the perimeter of the lower surface of the O-ring body (110). That is, the protrusion (120a) may be provided in the form of a ring with a circular cross section that protrudes in an inclined diagonal direction with respect to both the horizontal and vertical directions.
[0086] The sealing portion (120) may extend outwardly from the bottom surface (118) of the O-ring body (110) and protrude downward, and simultaneously extend outwardly from the outer surface portion (112) of the O-ring body (110) and protrude downward. The lower surface (123) of the sealing portion (120) and the bottom surface (118) of the O-ring body (110) may be connected by a curved inner surface (121) provided in the sealing portion (120).
[0087] To induce elastic deformation of the O-ring member (100), the O-ring body (110) and the sealing part (120) can be connected in a continuous planar and curved shape without angled corners, with the entire area from the respective outer surface portions (112, 122) to the lower surface (123) of the sealing part (120) and the bottom surface (118) of the O-ring body (110).
[0088] The bottom surface of the O-ring body (110) and the top surface of the sealing part (120) can be connected as a smooth, continuous flat or curved surface without gaps or protrusions on both the inner and outer surfaces. In this way, the O-ring member (100) according to the embodiment of the present invention is connected as a smooth curved surface from the top surface of the O-ring body (110) to the bottom surface of the sealing part (120) and to the bottom surface (118) of the O-ring body (110), thereby suppressing or mitigating the retention of electrolyte on the surface of the O-ring member (100), and even if some electrolyte remains on the surface of the O-ring member (100), it can be easily removed.
[0089] In addition, since there is no gap on the outer surface of the O-ring member (100), even if the O-ring member (100) is used repeatedly, cracks or damage are prevented in the gap formed on the outer surface of the O-ring member (100) due to repeated deformation, thereby extending the lifespan and usage cycle of the O-ring member (100). Accordingly, manufacturing costs associated with the electrolyte injection process can be reduced, and costs and time for maintenance of the parts can be saved.
[0090] The lower end of the protrusion (120a) constituting the sealing portion (120) may protrude downward by a lower protrusion distance (D2) from the bottom surface (118) of the O-ring body (110). The lower protrusion distance (D2) may be set, for example, to a distance within the range of 2 mm to 10 mm from the bottom surface (118) of the O-ring body (110).
[0091] If the lower protrusion distance (D2) of the protrusion (120a) protruding from the bottom surface (118) of the O-ring body (110) becomes smaller than 2 mm, it may be difficult for the protrusion (120a) to expand sufficiently outward in the radial direction, making it difficult to effectively seal the stepped area of the beading part (21) by the protrusion (120a).
[0092] Conversely, when the lower protrusion distance (D2) of the protrusion (120a) protruding from the bottom surface (118) of the O-ring body (110) exceeds 10 mm, it may be difficult to convert the pressure applied vertically to the protrusion (120a) toward the radially outward direction, and accordingly, it may be difficult to effectively seal the step area of the beading part (21) by the protrusion (120a).
[0093] The width (L1) of the protrusion (120a) in the horizontal direction can be designed to correspond to the inner diameter size of the battery housing (20). The width (L1) of the protrusion (120a) can be formed to be equal to the inner diameter of the battery housing (20) or slightly smaller within a set range. The difference between the inner diameter of the battery housing (20) and the width (L1) of the protrusion (120a) can be designed to be 1 mm or within a set range smaller than this.
[0094] The O-ring body (110) can press the protrusion (120a) downward by transmitting the downward pressure applied through the injection hopper (200) to the sealing part (120) while the sealing part (120) is seated on the beading part (21) of the battery housing (20). As the protrusion (120a) expands and deforms outward in the radial direction due to the reaction force of the pressure applied to the upper surface of the beading part (21), it can pressurize and seal the bent area provided along the upper circumference of the beading part (21).
[0095] The folded area of the beading portion (21) may be a curved area where the side wall of the battery housing (20) and the upper surface of the beading portion (21) intersect. The sealing portion (120) may be in close contact with the upper surface of the beading portion (21) and the inner surface of the side wall of the battery housing (20) within the folded area of the beading portion (21). For example, the protrusion (120a) may be in contact at the upper surface point (P1) of the beading portion (21) and the inner surface point (P2) of the side wall of the battery housing (20) to seal the folded area of the beading portion (21).
[0096] The pressure applied to the sealing part (120) acts as a force pushing the protrusion (120a) downward and a force pushing it outward in the horizontal direction in the radial direction, and accordingly, the protrusion (120a) is deformed into a shape that spreads outward in the radial direction and can also be pressed downward.
[0097] Accordingly, double sealing is performed at the upper surface point (P1) of the current collector (30) and the inner side wall point (P2) of the battery housing (20), so that the electrolyte can be effectively prevented from leaking to the outside. In addition, since sealing is secured at the upper surface point (P1) of the current collector (30), even if the thickness of the current collector (30) increases, the electrolyte does not leak into the folded area of the beading portion (21) of the current collector (30) and the battery housing (20), thereby preventing the electrolyte from remaining on the beading portion (21).
[0098] In order to effectively seal the step difference between the current collector (30) and the beading part (21) formed on the upper surface of the beading part (21) around the bending area of the beading part (21), the protrusion (120a) may be formed as a curved surface having a radius of curvature of 0.6 mm or more and less than 2 mm. More preferably, when the bending area of the beading part (21) has a radius of curvature within the range of 0.3 mm to 0.5 mm, the protrusion (120a) may be designed to have a radius of curvature (PI / 2) of 1.5 mm to 1.9 mm.
[0099] If the radius of curvature of the sealing portion (120) exceeds 1.9 mm, the step portion according to the thickness of the beading portion (21) and the current collector (30) is not perfectly sealed, and leakage of the electrolyte may occur. Conversely, if the radius of curvature of the sealing portion (120) is reduced to less than 0.6 mm, the amount of electrolyte remaining on the upper surface of the beading portion (21) may increase.
[0100] By means of the protrusion (120a) having the structure described above, the step portion between the beading portion (21) and a part of the current collector (30) (e.g., negative current collector) disposed on the upper surface of the beading portion (21) can be effectively sealed. Accordingly, the sealing / sealing performance in the folded area of the beading portion (21) can be improved. The O-ring member (100) for electrolyte injection according to an embodiment of the present invention is particularly advantageous for improving sealing performance during the process of injecting electrolyte using a hole injection method.
[0101] In addition, according to an embodiment of the present invention, the sealing performance of the step portion according to the thickness of the current collector (30) (negative current collector plate) is improved, thereby reducing the residual electrolyte in the beading portion (21). That is, the step portion of the current collector (30) is effectively sealed on the upper surface of the beading portion (21) to prevent leakage of the electrolyte and reduce the electrolyte remaining in the beading portion (21).
[0102] FIGS. 9a, 9b, and 10 are drawings showing experimental results illustrating the performance of an O-ring member for electrolyte injection according to an embodiment of the present invention. FIG. 9a is a cross-sectional view showing an O-ring member according to a comparative example that is compared with the performance of the O-ring member for electrolyte injection according to an embodiment of the present invention. FIG. 9b is a simulation result showing the contact distribution between the O-ring member according to the comparative example shown in FIG. 9a and the beading portion of the battery housing. FIG. 10 is a simulation result showing the contact distribution between the O-ring member for electrolyte injection according to an embodiment of the present invention and the beading portion of the battery housing.
[0103] In the simulation results shown in FIGS. 9b and FIGS. 10, the areas where the sealing between the O-ring member and the beading portion is poor and the areas where the sealing between the O-ring member and the beading portion is good are indicated by different shading. In the O-ring member according to the comparative example shown in FIG. 9a, an O-ring non-contact area (parts 'B' and 'C' in FIG. 9b) occurred due to the step difference caused by the welded cathode collector plate; however, in the case of the O-ring member for electrolyte injection according to the embodiment of the present invention, as shown in FIG. 10, it can be seen that no O-ring non-contact area occurs, and it is confirmed that the step difference caused by the cathode collector plate is effectively sealed.
[0104] Sealing Curvature Diameter (mm) Electrolyte Leakage Failure Amount of Residual Electrolyte in Beading Area Overall Result Not Applicable - Fig. 9a O-ring Defects High Poor 1.2 Good Low Excellent 1.8 Good Low Excellent 2.2 Good Low Excellent 3.5 Good Very Low Very Excellent 4.0 Poor Very Low Poor
[0105] Next, an experiment was conducted to measure whether there was a defect in electrolyte leakage and the amount of electrolyte remaining in the beading portion while varying the curvature diameter (twice the radius of curvature) of the sealing portion (120) of the O-ring member (100). The curvature diameter of the protrusion (120a) of the sealing portion (120) was varied to 1.2 mm, 1.8 mm, 2.2 mm, 3.5 mm, and 4.0 mm while measuring whether there was a defect in electrolyte leakage and the amount of electrolyte remaining in the beading portion. As a result of the experiment, in the case of the O-ring member according to the comparative example shown in FIG. 9a, not only was there leakage of electrolyte, but electrolyte also remained in the beading portion (21), so the sealing performance was evaluated as insufficient. When the curvature diameter of the sealing portion (120) was set to 4.0 mm, the step portion according to the thickness of the beading portion (21) and the current collector (30) was not completely sealed, and electrolyte leakage occurred.
[0106] When the curvature diameter of the sealing part (120) was set to 1.2 mm, 1.8 mm, 2.2 mm, or 3.5 mm, not only was the electrolyte not leaked, but the amount of electrolyte remaining in the beading part (21) was also small. In particular, when the curvature diameter of the sealing part (120) was set to 3.5 mm, it was confirmed that not only was the electrolyte leakage not occurring, but the amount of electrolyte remaining in the beading part (21) was also very small.
[0107] As described above, according to the O-ring member for injecting an electrolyte and the electrolyte injection device including the same according to an embodiment of the present invention, the sealing performance of the bent area provided on the upper surface of the beading portion of the battery housing can be improved, and in particular, the radius of curvature of the sealing portion (120) is formed in the range of 0.6 mm to 1.9 mm (the diameter of curvature is in the range of 1.2 mm to 3.8 mm) so that the step portion between the current collector placed on the beading portion of the battery housing and the beading portion can be effectively sealed to improve airtightness performance.
[0108] According to the O-ring member for electrolyte injection and the electrolyte injection device according to the embodiment of the present invention as described above, leakage of the electrolyte is prevented, thereby preventing the electrolyte from contaminating or damaging the working environment, injection equipment, or electronic components, and accordingly, maintenance costs and time can be reduced.
[0109] Furthermore, it can prevent safety risks that may arise from workers being exposed to volatile and chemically reactive electrolytes, and can also reduce the risk of fire. In addition, since the electrolyte can be injected into the battery housing in a precise amount, internal chemical reactions in the electrode assembly can be performed normally, thereby preventing degradation of the battery's performance and quality.
[0110] 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. An O-ring member for injecting electrolyte to seal the area around a beading portion into which the battery housing is drawn inward during the process of injecting electrolyte into a cylindrical battery housing constituting a battery cell, said battery housing, A cylindrical O-ring body having a groove portion at the top into which an injection hopper for injecting the electrolyte can be fitted, and an electrolyte injection passage formed vertically through the center through which the electrolyte can flow; and A sealing part comprising: a circular ring-shaped protrusion formed integrally with the above-mentioned O-ring body and protruding in a circular curved shape in an inclined direction toward the downward and outward directions along the lower circumference of the above-mentioned O-ring body; O-ring component for electrolyte injection.
2. In Claim 1, The above O-ring body is, With the sealing portion seated on the beading portion, the pressure applied downward through the injection hopper is transmitted to the sealing portion to press the protrusion downward. O-ring component for electrolyte injection.
3. In Claim 2, The above protrusion is, A bending area provided along the upper perimeter of the beading portion is configured to be pressure-sealed by expanding outward in the radial direction due to the reaction force of the pressure applied to the upper surface of the beading portion. O-ring component for electrolyte injection.
4. In Claim 3, The above-mentioned bending region is a curved region where the side wall of the battery housing and the upper surface of the beading portion intersect, and The sealing portion is in close contact with the upper surface of the beading portion and the inner surface of the side wall of the battery housing within the bending area. O-ring component for electrolyte injection.
5. In Claim 2, The above-mentioned protrusion has a radius of curvature of 0.6 mm or more and less than 2 mm, O-ring component for electrolyte injection.
6. In Claim 2, The bending area of the above beading portion has a radius of curvature within the range of 0.3 mm to 0.5 mm, The above protrusion has a radius of curvature within the range of 1.5 mm to 1.9 mm, O-ring component for electrolyte injection.
7. In Claim 1, The outer surface of the O-ring body and the sealing portion is formed as an inclined surface in which the outer diameter expands downward while forming a constant angle of inclination from the area below the groove portion. O-ring component for electrolyte injection.
8. In Claim 1, The above O-ring body and the above sealing part are, An entire area extending from the outer surface of the O-ring body and the sealing part to the lower surface of the sealing part and the bottom surface of the O-ring body is connected only by flat and curved surfaces without corners. O-ring component for electrolyte injection.
9. In Claim 1, The above protrusion is, A portion of the negative current collector disposed on the upper surface of the beading portion and configured to seal the step difference between the beading portion and the portion thereof. O-ring component for electrolyte injection.
10. O-ring member for electrolyte injection of Claim 1; and An electrolyte injection hopper disposed on the above-mentioned O-ring member for electrolyte injection; Electrolyte injection device including