Battery cell and battery pack and vehicle including same

Abstract

A battery cell, according to one embodiment of the present invention, may comprise: an electrode assembly which includes a first electrode, a second electrode, and a separator interposed therebetween; a battery housing which accommodates the electrode assembly via an open portion formed on one side thereof; a top cap assembly which covers the open portion, is electrically connected to the first electrode, and is electrically insulated from the battery housing; a sealing gasket which is interposed between the battery housing and the top cap assembly, and is configured to provide electrical insulation between the battery housing and the top cap assembly; and an expandable structure which is provided on at least a partial region of the sealing gasket, includes an expansion-scheduled state and an expanded state, and is configured to fill a gap between the sealing gasket and the top cap assembly in the expanded state.

Description

Battery cells and battery packs and vehicles containing the same

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

[0002] This application claims priority to Korean Patent Application No. 10-2023-0173552, filed on December 4, 2023, and all contents disclosed in the specification and drawings of the said application are incorporated by reference into this application.

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

[0004] Currently, widely used types of secondary batteries include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. The operating voltage of these unit secondary battery cells, i.e., unit battery cells, is approximately 2.5 V to 4.5 V. Therefore, when a higher output voltage is required, multiple battery cells are connected in series to form a battery pack. Furthermore, depending on the charge / discharge capacity required for the battery pack, a number of battery cells are connected in parallel to form a battery pack. Therefore, the number of battery cells included in the battery pack can be set in various ways depending on the required output voltage and / or charge / discharge capacity.

[0005] Meanwhile, the sealing gasket in contact with the crimping portion serves as a sealing and insulating layer between the top cap assembly and the battery housing. Conventional sealing gaskets enhance sealing power by applying asphalt pitch to the surface after injection molding. However, sealing gaskets with uneven asphalt pitch distribution on the surface have the problem of reducing sealing power. Furthermore, after the crimping process, a void is created due to the shape difference between the sealing gasket and the top cap assembly. This void creates a leakage path for electrolyte and / or gas when the internal pressure of the battery housing increases, increasing the risk of electrolyte leakage.

[0006] In one aspect, the present invention aims to eliminate the void between the top cap assembly and the sealing gasket after the crimping process.

[0007] In another aspect, the present invention has another object to reduce asphalt pitch residue applied to a sealing gasket.

[0008] However, the technical problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0009] According to one embodiment of the present invention for solving the above-described problem, a battery cell includes: an electrode assembly including a first electrode, a second electrode, and a separator interposed therebetween; a battery housing accommodating the electrode assembly through an opening formed at one side thereof; a top cap assembly covering the opening, electrically connected to the first electrode, and electrically insulated from the battery housing; a sealing gasket interposed between the battery housing and the top cap assembly and configured to electrically insulate between the battery housing and the top cap assembly; and an expandable structure provided in at least a portion of the sealing gasket, including a state scheduled for expansion and an expanded state, and configured to fill a gap between the sealing gasket and the top cap assembly when in the expanded state.

[0010] The above sealing gasket may include a material having insulating and elastic properties.

[0011] The above sealing gasket may include polybutylene terephthalate (PBT).

[0012] The sealing gasket may include a first part having a ring shape extending in a direction parallel to the axial direction of the battery cell and configured to be bent toward the inside of the battery cell; a second part extending horizontally from a lower end of the first part toward a central axis of the battery cell; and a third part extending downward from an inner end of the second part and having a radius smaller than a radius of the first part.

[0013] The above battery housing may have a beaded portion having an indented shape along its outer circumference.

[0014] The above sealing gasket can be seated on the beading portion.

[0015] The first part and the second part can be mounted on the beading portion.

[0016] The above expandable structure comprises a foaming agent, and the foaming agent may comprise at least one of ADCA, OBSH, DPT, or an inorganic material.

[0017] The above expandable structure comprises a foaming agent, and the foaming agent is capable of foaming at a temperature between 181 and 198 degrees Celsius.

[0018] The above expandable structure includes a foaming agent, and the foaming agent can be disposed on the inner surface of the sealing gasket.

[0019] The inflatable structure comprises a foaming agent, and the foaming agent can be disposed on the first part.

[0020] A battery cell characterized in that the expandable structure comprises a foaming agent, and the foaming agent is disposed in a central region of the first part.

[0021] The above expandable structure includes a foaming agent, and the foaming agent can be disposed in the bending region of the first part.

[0022] Meanwhile, the present invention provides a battery pack comprising at least one battery cell according to the above-described embodiment.

[0023] In addition, the present invention provides a vehicle including at least one battery pack according to the above-described embodiment.

[0024] According to the present invention, the empty space between the top cap assembly and the sealing gasket after the crimping process can be effectively eliminated.

[0025] In another aspect, according to the present invention, the asphalt pitch residue applied to the sealing gasket can be reduced.

[0026] However, the effects that can be obtained through the present invention are not limited to the effects described above, and other technical effects that are not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0027] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0028] FIG. 1 is a perspective view of a battery cell according to one embodiment of the present invention.

[0029] Figure 2 is a cross-sectional perspective view of Figure 1.

[0030] Figure 3 is a longitudinal cross-sectional view of Figure 1.

[0031] FIG. 4a is a perspective view of a sealing gasket included in the battery cell of FIG. 1.

[0032] FIG. 4b is a part of a longitudinal cross-sectional view of a sealing gasket included in the battery cell of FIG. 1.

[0033] FIG. 5 is a drawing for explaining a sealing gasket according to one embodiment of the present invention.

[0034] FIG. 6 is a drawing for explaining a sealing gasket according to another embodiment of the present invention.

[0035] FIG. 7 is a drawing for explaining a sealing gasket according to another embodiment of the present invention.

[0036] FIG. 8 is a drawing for explaining a sealing gasket according to another embodiment of the present invention.

[0037] FIG. 9 is a drawing for explaining the appearance of a battery cell before foaming according to one embodiment of the present invention.

[0038] FIG. 10 is a drawing for explaining the appearance of a battery cell after foaming according to one embodiment of the present invention.

[0039] FIG. 11 is a drawing for explaining a battery pack including the battery module of FIG. 1.

[0040] FIG. 12 is a drawing for explaining a vehicle including the battery pack of FIG. 11.

[0041] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, it should be noted that the terms and words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the concepts of terms to best explain his or her invention, they should be interpreted in a way that conforms to the technical spirit of the present invention.

[0042] Therefore, it should be understood that the embodiments described in this specification and the configurations illustrated in the drawings are only some of the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention, and that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0043] Additionally, to aid understanding of the invention, the attached drawings are not drawn to scale and the dimensions of some components may be exaggerated.

[0044]

[0045] Fig. 1 is a perspective view of a battery cell (1) according to one embodiment of the present invention, and Fig. 2 is a longitudinal cross-sectional perspective view of Fig. 1. Fig. 3 is a longitudinal cross-sectional view of Fig. 1.

[0046] Referring to FIGS. 1 and 2, a cylindrical battery cell (1) according to one embodiment of the present invention includes an electrode assembly (10), a battery housing (20), a top cap assembly (30), and a sealing gasket (40). The battery cell (1) may further include a current collector and / or a safety element (60).

[0047]

[0048] The electrode assembly (10) includes a first electrode having a first polarity, a second electrode having a second polarity, and a separator interposed between the first electrode and the second electrode. The first electrode is an anode or a cathode, and the second electrode corresponds to an electrode having a polarity opposite to that of the first electrode.

[0049] The electrode assembly (10) may have, for example, a jelly-roll structure. That is, the electrode assembly (10) may be manufactured by stacking a first electrode current collector and a second electrode current collector in a sheet shape at least once with a separator interposed therebetween, and winding the stack in one direction with the winding center (C) as the standard. In this case, an additional separator may be provided on the outer peripheral surface of the electrode assembly (10) for insulation from the battery housing (20). Any jelly-roll structure known in the art may be applied to the present invention without limitation.

[0050] The first electrode includes a first electrode current collector and a first electrode active material applied on one or both surfaces of the first electrode current collector. At one end of the first electrode current collector in the width direction (in the direction parallel to the Z-axis), there is a first uncoated portion (11) on which the first electrode active material is not applied. The first uncoated portion (11) functioning as a first electrode tab is hereinafter referred to as a first uncoated portion (11). The first uncoated portion (11) is provided at an upper portion in the height direction (in the direction parallel to the Z-axis) of the electrode assembly (10) accommodated in the battery housing (20). That is, the first electrode current collector includes a first uncoated portion (11) on which an active material layer is not coated at a long end and which is exposed to the outside of the separator, and a part of the first uncoated portion (11) is used as an electrode tab in and of itself. The first uncoated portion (11) may be, for example, a positive electrode tab.

[0051] Meanwhile, at least a portion of the first non-conductive portion (11) may include a plurality of segments divided along the winding direction of the electrode assembly (10). In this case, the plurality of segments may be bent along the radial direction of the electrode assembly (10). The plurality of bent segments may be overlapped in multiple layers.

[0052] The second electrode includes a second electrode current collector and a second electrode active material applied on one or both surfaces of the second electrode current collector. At the other end of the second electrode current collector in the width direction (parallel to the Z-axis), there is a first uncoated portion (11) on which the second electrode active material is not applied. The first uncoated portion (11) functioning as a second electrode tab is hereinafter referred to as a second uncoated portion (12). The second uncoated portion (11) is provided at the lower portion in the height direction (parallel to the Z-axis) of the electrode assembly (10) accommodated in the battery housing (20). That is, the second electrode current collector includes a second uncoated portion (12) on which an active material layer is not coated on a long end and which is exposed to the outside of the separator, and at least a portion of the second uncoated portion (12) is used as an electrode tab in its own right. The second uncoated portion (12) may be, for example, a positive electrode tab. Meanwhile, at least a portion of the second non-conductive portion (12) may include a plurality of segments divided along the winding direction of the electrode assembly (10). In this case, the plurality of segments may be bent along the radial direction of the electrode assembly (10). The plurality of bent segments may be overlapped in multiple layers.

[0053] The first non-conductive portion (11) and the second non-conductive portion (11) extend in opposite directions along the height direction (parallel to the Z-axis) of the cylindrical battery cell (1). The first non-conductive portion (11) extends toward the closed portion of the battery housing (20), and the second non-conductive portion (11) extends toward the open portion of the battery housing (20).

[0054] In the present invention, the positive electrode active material coated on the positive electrode plate and the negative electrode active material coated on the negative electrode plate can be used without limitation as long as they are active materials known in the art.

[0055]

[0056] The above battery housing (20) may be configured to include an opening on one side and accommodate the electrode assembly (10) through the opening.

[0057] Specifically, the battery housing (20) is a roughly cylindrical container with an opening formed at the bottom, and is made of a conductive material such as metal, for example. The material of the battery housing (20) may be, for example, steel, stainless steel, or nickel-plated iron. The upper surface located opposite the open portion will be referred to as a closed portion. The side wall portion and the closed portion of the battery housing (20) may be formed integrally. Alternatively, the side wall portion and the closed portion of the battery housing (20) may be provided separately and joined to each other by welding, etc. The upper surface of the battery housing (20) (the surface parallel to the XY plane), i.e., the outer surface of the closed portion, may have a roughly flat shape. The battery housing (20) accommodates the electrode assembly (10) through the opening formed at the bottom, and also accommodates an electrolyte.

[0058] The battery housing (20) is electrically connected to the electrode assembly (10). The battery housing (20) is electrically connected, for example, to the second non-conductive portion (12) of the electrode assembly (10). In this case, the battery housing (20) has the same polarity as the second non-conductive portion (12).

[0059]

[0060] The battery housing (20) may have a beading portion (21) and / or a crimping portion (22) formed at the upper end thereof. The beading portion (21) is formed adjacent to the upper opening of the battery housing (20). The beading portion (21) has a shape that is recessed inward along the outer circumference of the battery housing (20). That is, the beading portion (21) has a shape that is recessed to a predetermined depth in the radial direction from the outer circumference of the battery housing (20) and extends along the circumferential direction of the battery housing (20). The beading portion (21) prevents the electrode assembly (10) having a size corresponding to the width of the battery housing (20) from coming out through the upper opening of the battery housing (20), and may function as a support portion on which the top cap assembly (30) is seated.

[0061] The crimping portion (22) may be formed on the upper end of the battery housing (20). The crimping portion (22) may have a shape that extends inward along the radial direction of the cylindrical battery cell (1) from the upper periphery of the battery housing (20). The crimping portion (22) is provided in an area corresponding to the periphery of the upper surface of the top cap assembly (30) to fix the top cap assembly (30), thereby preventing the top cap assembly (30) from being separated upward. When the battery housing (20) is provided with a beading portion (21), the crimping portion (22) is formed on the upper end of the beading portion (21). The crimping portion (22) extends from the beading portion (21) and has a shape that extends and bends to surround the outer circumference of the top cap assembly (30) positioned on the beading portion (21) and a part of the upper surface of the top cap assembly (30). The upper end of the crimping portion (22) may have a shape that extends inwardly a predetermined distance along the radial direction of the cylindrical battery cell (1) and wraps around a portion of the upper surface of the top cap assembly (30). As a result, the crimping portion (22) fixes the edge perimeter of the upper surface of the top cap assembly (30). That is, the edge perimeter area of ​​the top cap assembly (30) is fixed to the battery housing (20) by being interposed between the upper end of the crimping portion (22) and the beading portion (21), and covers the opening of the battery housing (20).

[0062]

[0063] Referring to FIGS. 1 to 3, the top cap assembly (30) is a component made of a conductive metal material and covers the upper opening of the battery housing (20). The top cap assembly (30) is electrically connected to the first electrode of the electrode assembly (10) and is electrically insulated from the battery housing (20). Therefore, the top cap assembly (30) has the same first polarity as the first electrode of the electrode assembly (10) and can function as a first electrode terminal of the cylindrical battery cell (1) of the present invention. The electrical connection between the first electrode and the top cap assembly (30) can be made, for example, by a current collector (50) and / or a lead (51).

[0064] The top cap assembly (30) may be mounted on the beading portion (21) formed on the battery housing (20). The top cap assembly (30) is fixed by the crimping portion (22). That is, the edge of the lower surface of the top cap assembly (30) may be supported by the upper surface of the beading portion (21), and the edge of the upper surface may be fixed by bending the upper portion of the crimping portion (22). Meanwhile, a sealing gasket (40) may be interposed between the top cap assembly (30) and the crimping portion (22) of the battery housing (20) to seal the upper opening of the battery housing (20) and electrically insulate between the battery housing (20) and the top cap assembly (30). The sealing gasket (40) may include a material having insulating properties and elasticity. The sealing gasket (40) may include, for example, a polymer resin.

[0065] The above sealing gasket (40) can be bent along the bent shape of the crimping portion (22) of the battery housing (20). When the battery housing (20) has a beading portion (21), the sealing gasket (40) can be interposed between the upper surface of the beading portion (21) and the upper end of the crimping portion (22).

[0066]

[0067] In another aspect of the present invention, the top cap assembly (30) may include a top cap (31) and a venting member (32).

[0068] The top cap assembly (30) may be provided with a top cap (31) that protrudes upward from approximately the center thereof. More specifically, the top cap (31) may be positioned approximately at the center of the top cap assembly (30) and configured to protrude upward. The top cap (31) may be provided at a position corresponding to a hole formed approximately at the center of the battery cell (1). The top cap (31) may protrude upward higher than the upper surface of the battery housing so as to facilitate contact with electrical connection components such as a bus bar.

[0069] The venting member (32) may be a roughly plate-shaped structure that surrounds the outer periphery of the top cap (31). The venting member (32) may be configured to support the top cap (31) from below and to wrap upward around the edge of the top cap (31). Accordingly, the end of the venting member (32) is positioned on the upper surface of the top cap (31). Meanwhile, the pressure inside the battery housing (20) may increase as the battery is charged and discharged, and at this time, if the venting member (32) cannot withstand the pressure, it may flip upward and the notch portion may be broken. At this time, the venting gas may be discharged to the outside of the venting member (32) through the broken portion. Meanwhile, although not specifically illustrated in the drawing, the top cap (31) may be provided with an exhaust port that can discharge such venting gas to the outside. Therefore, the venting gas discharged to the outside of the venting member (32) can be finally discharged to the outside of the battery cell (1) through the exhaust port provided in the top cap (31).

[0070] Meanwhile, the first electrode of the electrode assembly (10) can be coupled to the lower surface of the venting member (32) via the lead (51) and / or the safety element (60). Therefore, the venting member (32) has the same electrode as the first electrode. Meanwhile, since the venting member (32) surrounds the edge of the top cap (31), the top cap (31) also has the same electrode as the first electrode.

[0071]

[0072] FIG. 4a is a perspective view of a sealing gasket (40) included in a battery cell (1) of FIG. 1, and FIG. 4b is a part of a longitudinal cross-sectional view of a sealing gasket (40) included in a battery cell (1) of FIG. 1.

[0073] In one aspect of the present invention, the venting member (32) may include a bumpy region (32P) configured to have a bumpy surface. The bumpy region (32P) may be provided on at least a portion of the venting member (32). For example, as represented in FIG. 4B, the bumpy region (32P) may be provided on at least a portion of the lower surface of the venting member (32). For example, the bumpy region (32P) may be provided on a surface of the venting member (32) that comes into contact with the sealing gasket (40).

[0074] According to this structure, the contact area between the sealing gasket (40) and the top cap assembly (30) increases and friction increases, so that the sealing force between the sealing gasket (40) and the top cap assembly (30) can be improved.

[0075]

[0076] Referring to FIGS. 1 to 4B, the sealing gasket (40) may be interposed between the battery housing (20) and the top cap assembly (30). For example, the sealing gasket (40) may be interposed between the crimping portion (22) of the battery housing (20) and the top cap assembly (30). More specifically, the sealing gasket (40) may be interposed between the upper surface of the beading portion (21) and the upper end of the crimping portion (22). The sealing gasket (40) may seal the upper opening of the battery housing (20). The sealing gasket (40) may be configured to electrically insulate between the battery housing (20) and the top cap assembly (30).

[0077]

[0078] In one aspect of the present invention, the sealing gasket (40) may include an expandable structure (B) including a state that is expected to be expanded and an expanded state in at least a portion thereof. The expandable structure (B) may be configured to fill a gap between the sealing gasket (40) and the top cap assembly (30) when in the expanded state. The expandable structure (B) may include a foaming agent. At least a portion of the sealing gasket (40) may be coated with the foaming agent. For example, the foaming agent may include at least one of ADCA, OBSH, DPT, or an inorganic material.

[0079] The blowing agent may be configured to foam within a specific temperature and / or pressure range. For example, when the blowing agent comprises ADCA (azodicarbonamide), the blowing agent may foam at a temperature of approximately 181 to 198 degrees Celsius.

[0080] According to the features of the present invention, the empty space (G) generated between the top cap assembly (30) and the sealing gasket (40) in the beading and crimping process can be easily filled. Here, the crimping process refers to a process of sealing the battery cell (1). Specifically, the crimping process is a process of sealing the inside of the battery cell (1) from the outside by pressing the sealing gasket (40) mounted on the upper portion of the battery cell (1) and the upper portion of the battery housing together toward the inside of the battery cell (1). Meanwhile, during the crimping process, the sealing gasket (40) may be bent in a direction toward the inside of the battery cell (1). Specifically, the sealing gasket (40) may be bent together along the bent shape of the crimping portion (22) of the battery housing (20). At this time, since the shape of the inner surface of the bent sealing gasket (40) does not perfectly match the shape of the outer surface of the top cap assembly (30) that comes into contact with the inner surface of the sealing gasket (40), a predetermined empty space (G) is often formed between the top cap assembly (30) and the sealing gasket (40). In such a case, since the empty space (G) forms a leakage path for electrolyte and / or gas when the pressure inside the battery increases, there is a high possibility that the risk of leakage will increase.

[0081] On the other hand, according to the present invention, even if a void (G) is created between the top cap assembly (30) and the sealing gasket (40) as described above, the void (G) can be completely filled by foaming the foaming agent coated on the sealing gasket (40) under certain conditions. Accordingly, according to the present invention, the risk of electrolyte and / or gas leakage inside the battery can be effectively reduced.

[0082]

[0083] In another aspect of the present invention, the sealing gasket (40) may include a material having insulating and elastic properties. The sealing gasket (40) may include a polymer resin. For example, the sealing gasket (40) may include polybutylene terephthalate (PBT). However, it should be understood that the material of the sealing gasket (40) of the present invention is not limited thereto.

[0084] According to these features of the present invention, the sealing gasket (40) can be easily bent during the crimping process. Furthermore, coating the surface of the sealing gasket (40) with a foaming agent can be facilitated. Furthermore, because the sealing gasket (40) is elastic, its shape can be deformed to adhere closely to surrounding components. Consequently, the sealing force can be further enhanced.

[0085]

[0086] Referring to FIGS. 4a and 4b, the sealing gasket (40) may include a first part (41); a second part (42); and a third part (43). The sealing gasket (40) may further include a fourth part (44).

[0087] More specifically, the first part (41) may be configured to have a ring shape extending in a direction parallel to the axial direction of the battery cell (1). The first part (41) may have a cylindrical shape having a predetermined radius. That is, as can be seen in FIGS. 4A and 4B, the first part (41) may be configured to have an approximately pipe shape having a predetermined height.

[0088] The first part (41) may be bent in a direction toward the inside of the battery cell (1). Specifically, the first part (41) may be bent together along the bent shape of the crimping portion (22) of the battery housing (20). At this time, the bent portion may be configured to be perpendicular to the axial direction of the battery cell (1). Consequently, the shape of the first part (41) after being bent may have an approximately “ㄱ” shape bent toward the inside of the battery cell (1).

[0089] The above first part (41) can be mounted on the beading portion (21). That is, the lower end of the first part (41) can be configured to be in contact with the beading portion (21).

[0090] The second part (42) may be configured to extend horizontally from the lower end of the first part (41) toward the central axis of the battery cell (1). That is, the second part (42) may be configured to be perpendicular to the axial direction of the battery cell (1). For example, the second part (42) may have a token shape with a predetermined width.

[0091] In another aspect of the present invention, the second part (42) may include a bumpy area (42P) configured to have a bumpy surface. The bumpy area (42P) may be provided on at least a portion of the second part (42). For example, as represented in FIG. 4B, the bumpy area (42P) may be provided on at least a portion of the upper surface of the second part (42). For example, the bumpy area (42P) may be provided on a surface of the second part (42) that comes into contact with the top cap assembly (30).

[0092] According to this structure, the contact area between the sealing gasket (40) and the top cap assembly (30) increases and friction increases, so that the sealing force between the sealing gasket (40) and the top cap assembly (30) can be improved. If, as in Fig. 4b, a bumpy area (32P) is also included on the top cap assembly (30), the sealing force can be further improved.

[0093] Preferably, the bump area (42P) provided in the sealing gasket (40) and the bump area (32P) provided in the top cap assembly (30) may be configured to have complementary shapes. For example, the bump area (42P) provided in the sealing gasket (40) and the bump area (32P) provided in the top cap assembly (30) may be configured to have a sawtooth shape that interlocks with each other.

[0094] According to this structure, the contact area between the sealing gasket (40) and the top cap assembly (30) is increased and friction is further increased, so the sealing force between the sealing gasket (40) and the top cap assembly (30) is further improved.

[0095] In another aspect of the present invention, the second part (42) can be mounted on the beading portion (21). That is, a horizontally extending portion of the second part (42) can be mounted on the beading portion (21). Accordingly, the second part (42) can support the top cap assembly (30).

[0096] The third part (43) may extend downward from the inner end of the second part (42). The third part (43) may be configured to have a radius smaller than the radius of the first part (41). The third part (43) may be configured to have a ring shape extending in a direction parallel to the axial direction of the battery cell (1). The third part (43) may have a cylindrical shape having a predetermined radius. That is, as can be seen in FIGS. 4A and 4B, the third part (43) may be configured to have an approximately pipe shape having a predetermined height.

[0097] The sealing gasket (40) may further include a fourth part (44). The fourth part (44) may be configured to extend horizontally from the third part (43) toward the central axis of the battery cell (1). For example, the fourth part (44) may be configured to extend horizontally from the center point of the third part (43) toward the central axis of the battery cell (1). The second part (42) may be configured to be perpendicular to the axial direction of the battery cell (1). For example, the second part (42) may have a token shape with a predetermined width. The fourth part (44) may be configured to support the safety element (60). For example, the fourth part (44) may support the safety element (60) upward.

[0098]

[0099] FIG. 5 is a drawing for explaining a sealing gasket (40) according to one embodiment of the present invention.

[0100] In one aspect of the present invention, the sealing gasket (40) may have a foaming agent applied to at least a portion of the sealing gasket (40). For example, as in the embodiment of FIG. 5, the foaming agent may be coated over the entire area of ​​the sealing gasket (40).

[0101] With this structure, the coating process of the sealing gasket (40) can be facilitated. This simplifies the manufacturing process and ensures economic efficiency. Furthermore, with this feature of the present invention, the empty space (G) created between the top cap assembly (30) and the sealing gasket (40) during the beading and crimping process can be completely filled. Accordingly, the present invention can effectively reduce the risk of electrolyte and / or gas leakage within the battery.

[0102]

[0103] FIG. 6 is a drawing for explaining a sealing gasket (40) according to another embodiment of the present invention.

[0104] In another aspect of the present invention, the sealing gasket (40) may have a foaming agent applied to at least a portion thereof. More specifically, the foaming agent may be coated on the inner surface of the sealing gasket (40). Here, the inner surface refers to a surface of the sealing gasket (40) facing the central axis of the battery cell (1), based on the sealing gasket (40). Conversely, the outer surface refers to a surface facing the outside of the battery cell (1), based on the sealing gasket (40). Meanwhile, since the leakage path of the electrolyte and / or gas is in contact with the inner side of the sealing gasket (40), not the outer side, coating the foaming agent on the inner surface of the sealing gasket (40) allows the empty space (G) generated between the top cap assembly (30) and the sealing gasket (40) during the beading and crimping process to be filled without a gap.

[0105] Accordingly, the present invention effectively reduces the risk of electrolyte and / or gas leakage within the battery. Furthermore, the above embodiment eliminates the need to coat the outer surface of the sealing gasket (40) with a foaming agent, thereby reducing costs. Furthermore, the present invention is not affected by microscopic errors that may arise from foaming agent coating.

[0106]

[0107] FIG. 7 is a drawing for explaining a sealing gasket (40) according to another embodiment of the present invention.

[0108] In another aspect of the present invention, the foaming agent may be coated on the first part (41). For example, referring to FIG. 7, it can be confirmed that the foaming agent is coated on at least a portion of the first part (41). The empty space (G) generated between the top cap assembly (30) and the sealing gasket (40) during the crimping process mainly occurs at a portion where the venting member (32) is bent while wrapping the top cap (31). Therefore, even if the foaming agent is coated only on the area where the venting member (32) of the top cap assembly (30) and the sealing gasket (40) come into contact, the effects of the present invention can be obtained. At this time, the area where the venting member (32) of the top cap assembly (30) and the sealing gasket (40) come into contact mainly corresponds to the first part (41) and the second part (42) of the sealing gasket (40). Here, the area where the venting member (32) is bent can particularly come into contact with the first part (41) of the sealing gasket (40).

[0109] Therefore, according to the present embodiment of coating the first part (41) of the sealing gasket (40) with a foaming agent, as in the present invention, the risk of electrolyte and / or gas leakage inside the battery can be effectively reduced. In addition, according to the above embodiment, since there is no need to coat the second part (42), third part (43), etc. of the sealing gasket (40) with a foaming agent, costs can be saved. In addition, it is not affected by minute errors that may occur due to the foaming agent coating.

[0110]

[0111] FIG. 8 is a drawing for explaining a sealing gasket (40) according to another embodiment of the present invention.

[0112] In another aspect of the present invention, the foaming agent may be coated on a central region of the first part (41). Preferably, the foaming agent may be coated on a folded region of the first part (41). For example, referring to FIG. 8, the foaming agent may be coated on a central region of the first part (41) among the first parts (41). In one embodiment of the present invention, the axial height of the top cap assembly (30) seated on the sealing gasket (40) may be lower than about 1 / 2 of the axial height of the first part (41). With this structure, the sealing gasket (40) can sufficiently cover the top cap assembly (30). If the axial height of the top cap assembly (30) seated on the sealing gasket (40) is greater than about 1 / 2 of the axial height of the first part (41), the area between the sealing gaskets (40) covering the upper surface of the venting member (32) becomes narrow, and the sealing force may be weakened.

[0113] Therefore, considering this structure, it is preferable that the foaming agent be coated on the central region of the first part (41). More preferably, the foaming agent may be coated on the folded region of the first part (41). Referring to Fig. 8, the venting member (32) may be folded while wrapping around the top cap (31). At this time, the foaming agent may be coated intensively around the folded point of the venting member (32).

[0114] Accordingly, the present invention effectively reduces the risk of electrolyte and / or gas leakage within the battery. Furthermore, the above embodiment eliminates the need to coat the outer surface of the sealing gasket (40) with a foaming agent, thereby reducing costs. Furthermore, the present invention is not affected by microscopic errors that may arise from foaming agent coating.

[0115]

[0116] FIG. 9 is a drawing for explaining the appearance of a battery cell (1) according to one embodiment of the present invention before foaming, and FIG. 10 is a drawing for explaining the appearance of a battery cell (1) according to one embodiment of the present invention after foaming.

[0117] Fig. 9 shows a sealed battery cell (1) after the crimping process. That is, by pressing the sealing gasket (40) mounted on the upper portion of the battery cell (1) and the upper portion of the battery housing together toward the inside of the battery cell (1), the inside of the battery cell (1) is sealed from the outside. In this crimping process, the sealing gasket (40) may be bent in a direction toward the inside of the battery cell (1). Specifically, the sealing gasket (40) may be bent together along the bent shape of the crimping portion (22) of the battery housing (20). At this time, since the shape of the inner surface of the bent sealing gasket (40) does not perfectly match the shape of the outer surface of the top cap assembly (30) that comes into contact with the inner surface of the sealing gasket (40), a predetermined empty space (G) is often formed between the top cap assembly (30) and the sealing gasket (40). Meanwhile, during the crimping process, since the battery housing (20) receives a force in a direction perpendicular to the surface of the crimping portion (22), the top cap assembly (30) may be pushed further inward of the battery cell (1). Accordingly, a predetermined empty space (G) between the top cap assembly (30) and the sealing gasket (40) may become larger. In this case, since the empty space (G) forms a leakage path for electrolyte and / or gas when the pressure inside the battery increases, there is a high possibility that the risk of leakage may increase. However, according to one embodiment of the present invention, as shown in FIG. 9, a foaming agent is coated around the empty space (G). More specifically, the foaming agent may be coated on the surface of the sealing gasket (40) facing the empty space (G). The foaming agent may be foamed under predetermined temperature and pressure conditions. For example, when the foaming agent includes ADCA (azodicarbonamide), the foaming agent can foam at a temperature between 181 and 198 degrees Celsius.

[0118] Figure 10 illustrates a state in which the foaming agent is foamed at a predetermined temperature and pressure. The foaming agent can foam and completely fill the empty space (G). Accordingly, no empty space (G) is created between the sealing gasket (40) and the top cap assembly (30). Furthermore, since the volume of the foaming agent increases as it foams, the sealing force can be further improved. Accordingly, the possibility of the electrolyte and / or gas contained within the battery housing (20) leaking outside the battery housing (20) can be significantly reduced.

[0119] In this way, according to the present invention, even if a void (G) is created between the top cap assembly (30) and the sealing gasket (40) as described above, the void (G) can be completely filled by foaming the foaming agent coated on the sealing gasket (40) under certain conditions. Accordingly, according to the present invention, the risk of electrolyte and / or gas leakage inside the battery can be effectively reduced.

[0120] Meanwhile, the expandable structure (B) of the present invention can be accommodated within a receiving space provided in the sealing gasket (40). In this case, the sealable structure (B) can be stably positioned between the sealing gasket (40) and the top cap assembly (30) even when not inflated. For example, the expandable structure (B) can be at least partially inserted into a groove provided in a portion of the sealing gasket (40).

[0121]

[0122] Meanwhile, the current collector (50) is coupled to the upper portion of the electrode assembly (10). The current collector (50) may be positioned between the electrode assembly (10) and the beading portion (21). The current collector (50) is made of a conductive metal material and is coupled to the first non-conductive portion (11). The current collector (50) is electrically connected to the top cap assembly (30). A lead (51) may be connected to the current collector (50), and the lead (51) may extend upward and be directly coupled to the top cap assembly (30) or may be coupled to a safety element (60) coupled to the lower surface of the top cap assembly (30). Accordingly, the top cap assembly (30) may have the same first polarity as the first non-conductive portion (11) and may function as a first electrode terminal.

[0123]

[0124] FIG. 11 is a drawing for explaining a battery pack including the battery module of FIG. 1.

[0125] Referring to Fig. 11, a battery pack (3) according to the present invention may include at least one battery cell (1) according to the present invention described above. In addition, the battery pack (3) according to the present invention may include a pack case (2) capable of accommodating the at least one battery cell (1). In addition, in addition to the battery cell (1), the battery pack (3) may further include various other components, such as components of the battery pack (3) known at the time of filing of the present invention, such as a BMS, a pack case, a relay, a current sensor, etc.

[0126]

[0127] FIG. 12 is a drawing for explaining a vehicle including the battery pack of FIG. 11.

[0128] Referring to FIG. 12, a vehicle (5) according to the present invention may include at least one battery pack (3) according to the present invention.

[0129] The battery module according to the present invention can be applied to automobiles such as electric vehicles or hybrid vehicles. That is, an automobile according to the present invention may include a battery module according to the present invention or a battery pack according to the present invention. Furthermore, an automobile according to the present invention may further include various other components included in the automobile in addition to the battery module or battery pack. For example, an automobile according to the present invention may further include a body, a motor, a control device such as an electronic control unit (ECU), and the like, in addition to the battery module according to the present invention.

[0130]

[0131] Meanwhile, although terms indicating directions such as up and down are used in this specification, it is obvious to those skilled in the art that these terms are only for convenience of explanation and may vary depending on the location of the target object or the location of the observer.

[0132] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0133] [Drawing reference symbol]

[0134] 5 cars

[0135] 3 battery packs

[0136] 2 pack case

[0137] 1 battery cell

[0138] 10 electrode assembly

[0139] 11th 1st Military Department

[0140] 12. Second Military Department

[0141] 20 battery housing

[0142] 21 Bidding Department

[0143] 22 Crimping section

[0144] 30 Top Cap Assembly

[0145] 31 Top Cap

[0146] 32 Absence of venting

[0147] 40 sealing gasket

[0148] 41 Part 1

[0149] 42 Part 2

[0150] 43 Part 3

[0151] 44 Part 4

[0152] B foaming agent

[0153] 50 whole house

[0154] 51 leads

[0155] 60 safety elements

Claims

1. An electrode assembly including a first electrode, a second electrode, and a separator interposed therebetween; A battery housing accommodating the electrode assembly through an opening formed on one side; A top cap assembly covering the opening, electrically connected to the first electrode, and electrically insulated from the battery housing; A sealing gasket interposed between the battery housing and the top cap assembly and configured to electrically insulate between the battery housing and the top cap assembly; and A battery cell comprising an expandable structure provided on at least a portion of the sealing gasket, the expandable structure including a state scheduled for expansion and an expanded state, and configured to fill a gap between the sealing gasket and the top cap assembly when in the expanded state.

2. In paragraph 1, A battery cell, wherein the sealing gasket comprises a material having insulating and elastic properties.

3. In paragraph 1, A battery cell, characterized in that the sealing gasket comprises polybutylene terephthalate (PBT).

4. In paragraph 1, The above sealing gasket, A first part having a ring shape extending in a direction parallel to the axial direction of the battery cell and configured to be bent toward the inside of the battery cell; A second part extending horizontally from the lower end of the first part toward the central axis of the battery cell; and A third part extending downward from the inner end of the second part and having a radius smaller than that of the first part A battery cell characterized by including a .

5. In paragraph 4, A battery cell characterized in that the battery housing has a beading portion having an indented shape along the outer circumference thereof.

6. In paragraph 5, A battery cell characterized in that the sealing gasket is seated on the beading portion.

7. In paragraph 5, A battery cell, characterized in that the first part and the second part are mounted on the beading portion.

8. In paragraph 1, The above expandable structure comprises a foaming agent, A battery cell characterized in that the foaming agent comprises at least one of ADCA, OBSH, DPT, or an inorganic material.

9. In paragraph 1, The above expandable structure comprises a foaming agent, A battery cell characterized in that the foaming agent foams at a temperature between 181 and 198 degrees Celsius.

10. In paragraph 1, The above expandable structure comprises a foaming agent, A battery cell, characterized in that the foaming agent is disposed on the inner surface of the sealing gasket.

11. In paragraph 4, The above expandable structure comprises a foaming agent, A battery cell, characterized in that the foaming agent is disposed on the first part.

12. In paragraph 4, The above expandable structure comprises a foaming agent, A battery cell, characterized in that the foaming agent is disposed in the central region of the first part.

13. In paragraph 4, The above expandable structure comprises a foaming agent, A battery cell, characterized in that the foaming agent is placed in the bending area of ​​the first part.

14. A battery pack comprising at least one battery cell according to any one of claims 1 to 13.

15. A vehicle comprising at least one battery pack according to paragraph 14.

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