Rechargeable battery

Abstract

This rechargeable battery comprises an electrode assembly, a case, and a current collecting plate. The case accommodates the electrode assembly and includes a bottom part and a side part connected to the bottom part and provided with a beading portion and a crimping portion. The current collecting plate is provided with: a main body fixed to one side of the electrode assembly; and a connector that extends from the main body toward the beading portion and comes into contact with the beading portion. The beading portion includes: a support section that intersects with the side part and faces the crimping portion; and a beading curved section located between the side part and the support section. The connector includes: a first connecting section in contact with the support section; and a second connecting section in contact with the beading curved section.

Description

secondary battery

[0001] The present disclosure relates to a secondary battery, and more particularly, to a secondary battery having a current collector plate.

[0002] Secondary batteries are used in a variety of applications, including powering small electronic devices such as mobile phones and laptop computers, and powering motors in vehicles such as electric and hybrid vehicles. Secondary batteries can be categorized by their external shape into cylindrical, prismatic, and pouch-shaped types. Cylindrical secondary batteries may include a rolled electrode assembly and a pair of current collectors secured to the electrode assembly.

[0003] A pair of current collector plates may include a positive current collector plate and a negative current collector plate. One of the pair of current collector plates may have a connector that contacts a bead portion of the case. The connector may be secured to the bead portion by welding or other methods. An insulating gasket may be positioned surrounding the edge of the cap plate at the portion where the bead portion and the connector are secured.

[0004] The present disclosure aims to provide a secondary battery capable of suppressing damage caused by welding by improving the joint structure of a beading portion and a connector, and improving the sealing performance of an insulating gasket.

[0005] According to one embodiment, a secondary battery includes an electrode assembly, a case, and a current collector. The electrode assembly includes a first electrode, a separator, and a second electrode. The case includes a bottom portion, a side portion connected to the bottom portion and having a beading portion and a crimping portion, and accommodates the electrode assembly. The current collector has a body fixed to one side of the electrode assembly, and a connector extending from the body toward the beading portion and contacting the beading portion. The beading portion includes a support portion intersecting the side portion and facing the crimping portion, and a beading curved portion positioned between the side portion and the support portion. The connector includes a first connection portion contacting the support portion, and a second connection portion contacting the beading curved portion.

[0006] The first connecting portion may have the same angle as the support portion with respect to the side and may be placed in close contact with the support portion. The second connecting portion may have a curvature corresponding to the beading curved portion and may be placed in close contact with the beading curved portion. The connector may further include a third connecting portion positioned between the main body and the first connecting portion. The third connecting portion may include at least one bent portion and at least two straight portions.

[0007] On the other hand, the connector may include a first connector and a second connector connecting the body and the first connector. The first connector may include a first connector, a second connector, and an extension extending from the first connector toward the interior of the case. The extension may be parallel to the first connector, and a length of the extension may be greater than a length of the first connector. One end of the second connector may be fixed to a surface of the first connector facing the body, and the other end of the second connector may be fixed to the body. The second connector may include at least one bent portion and at least two straight portions.

[0008] The secondary battery may further include a weld portion positioned between the beading curved portion and the second connecting portion. Alternatively, the secondary battery may further include a first weld portion positioned between the beading curved portion and the second connecting portion, and a second weld portion positioned between the support portion and the first connecting portion.

[0009] The secondary battery may further include a cap plate secured between the beading portion and the crimping portion via an insulating gasket to seal the case. The insulating gasket may be maintained in a non-contact state with the beading portion by the connector. The portion of the insulating gasket located between the cap plate and the connector may have a constant thickness.

[0010] According to another embodiment, a secondary battery includes an electrode assembly, a case, a cap plate, and a current collector. The case includes a bottom portion, a side portion connected to the bottom portion and having a beading portion and a crimping portion, and accommodates the electrode assembly. The cap plate is secured between the beading portion and the crimping portion via an insulating gasket to seal the case. The current collector has a body secured to one side of the electrode assembly, and a connector extending from the body toward the beading portion and contacting the beading portion. The beading portion includes a support portion intersecting the side portion and facing the crimping portion, and a beading curved portion positioned between the side portion and the support portion. The connector includes a first connection portion contacting the support portion and a second connection portion contacting the beading curved portion. The beading portion and the connector are secured by a weld portion positioned between the beading curved portion and the second connection portion.

[0011] The insulating gasket can be maintained in a non-contact state with the beading portion by the connector. The portion of the insulating gasket located between the cap plate and the connector can have a certain thickness.

[0012] The connector may further include a third connector positioned between the body and the first connector. The third connector may include at least one bent portion and at least two straight portions.

[0013] On the other hand, the connector may include a first connector and a second connector connecting the body and the first connector. The first connector may include a first connector, a second connector, and an extension extending from the first connector toward the interior of the case. The extension may be parallel to the first connector, and a length of the extension may be greater than a length of the first connector. One end of the second connector may be fixed to a surface of the first connector facing the body, and the other end of the second connector may be fixed to the body. The second connector may include at least one bent portion and at least two straight portions.

[0014] According to embodiments, the lower portion of the insulating gasket can have a constant thickness without any step. Furthermore, the insulating gasket can maintain a constant pressure distribution and prevent stress from being concentrated in a specific area. As a result, the insulating gasket can stably exhibit sealing performance for a long period of time, thereby improving the durability of the secondary battery.

[0015] Figure 1 is a perspective view of a secondary battery according to the first embodiment.

[0016] Figure 2 is a cross-sectional view of the secondary battery illustrated in Figure 1.

[0017] Figure 3 is an exploded perspective view showing the unfolded state of the electrode assembly of the secondary battery illustrated in Figure 2.

[0018] Fig. 4 is a partially enlarged cross-sectional view of an electrode assembly of the secondary battery illustrated in Fig. 2.

[0019] Figure 5 is a partially enlarged view of the secondary battery illustrated in Figure 2.

[0020] Figure 6 is a partially enlarged view of Figure 5.

[0021] Figure 7 is a partially enlarged cross-sectional view of a secondary battery according to a comparative example.

[0022] Figure 8 is a partially enlarged cross-sectional view of a secondary battery according to the second embodiment.

[0023] Fig. 9 is a partially enlarged cross-sectional view of a secondary battery according to the third embodiment.

[0024] Hereinafter, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0025] Fig. 1 is a perspective view of a secondary battery according to the first embodiment. Fig. 2 is a cross-sectional view of the secondary battery illustrated in Fig. 1.

[0026] Referring to FIGS. 1 and 2, the secondary battery (100) of the present embodiment may be a cylindrical secondary battery. The secondary battery (100) may include a cylindrical case (120), an electrode assembly (130) accommodated inside the case (120), a terminal portion (140) provided on one side (e.g., the lower side) of the case (120), and a cap plate (150) provided on the other side (e.g., the upper side) of the case (120). A first collector plate (160) and a second collector plate (170) may be fixed to both sides (upper and lower sides) of the electrode assembly (130).

[0027] The case (120) may include a disc-shaped bottom portion (121) and a cylindrical side portion (122) extending upward from the edge of the bottom portion (121). The case (120) may be made of, for example, steel, aluminum, an aluminum alloy, etc. When the top and bottom of the secondary battery (100) are reversed, the bottom portion (121) may be referred to as the upper surface or top portion.

[0028] Fig. 3 is an exploded perspective view showing the unfolded state of the electrode assembly of the secondary battery illustrated in Fig. 2. Fig. 4 is a partially enlarged cross-sectional view of the electrode assembly of the secondary battery illustrated in Fig. 2.

[0029] Referring to FIGS. 3 and 4, the electrode assembly (130) may be configured such that a laminate including a first electrode (10), a separator (30), and a second electrode (20) is wound multiple times around a center pin (not shown). Each of the first electrode (10), the separator (30), and the second electrode (20) may be in the shape of a long strip, and the laminate may be wound in the shape of a jelly roll.

[0030] The laminate may be configured in the order of a first electrode (10), a separator (30), a second electrode (20), and a separator (30). At this time, the positions of the first electrode (10) and the second electrode (20) may be exchanged. The center pin may be removed after the laminate is wound, in which case an empty space may be located at the center of the electrode assembly (130). The first electrode (10) may be referred to as a cathode, and the second electrode (20) may be referred to as an anode.

[0031] The first electrode (10) may include a first substrate (11) and a first active material layer (12) positioned on at least one surface of the first substrate (11). The first substrate (11) may be referred to as a negative electrode current collector, and the first active material layer (12) may be referred to as a negative electrode active material layer. The first substrate (11) may be made of copper, nickel, a copper alloy, a nickel alloy, or the like, and may be in the form of a thin plate or foam. The first active material layer (12) includes a negative electrode active material, and may optionally further include a binder and / or a conductive material.

[0032] In the first active material layer (12), the negative electrode active material may include at least one of a carbon-based active material, an alloy of lithium metal, and a silicon-carbon composite active material. The carbon-based negative electrode active material may include at least one of natural graphite and artificial graphite. The lithium metal alloy may be an alloy of lithium and a metal selected from Na, K, Pb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Ba, Ra, Ge, Al, and Sn.

[0033] The silicon-carbon composite active material may include at least one of a first negative electrode active material, a second negative electrode active material, and a third negative electrode active material. The first negative electrode active material may include a plurality of silicon nanoparticles and an amorphous carbon coating layer positioned on the surfaces of the silicon nanoparticles. The second negative electrode active material may include a core comprising a silicon-carbon composite and a polymer coating layer positioned on the core. The third negative electrode active material may include a core comprising a silicon-based material and a carbon-based coating layer positioned on the core.

[0034] The second electrode (20) may include a second substrate (21) and a second active material layer (22) positioned on at least one surface of the second substrate (21). The second substrate (21) may be referred to as a positive electrode current collector, and the second active material layer (22) may be referred to as a positive electrode active material layer. The second substrate (21) may be made of aluminum or the like, and may be in the form of a thin plate or foam. The second active material layer (22) includes a positive electrode active material, and may optionally further include a binder and / or a conductive material.

[0035] In the second active material layer (22), the positive electrode active material may include a lithium transition metal composite oxide. The lithium transition metal composite oxide may include, for example, at least one of a lithium-nickel-based oxide, a lithium-cobalt-based oxide, a lithium-manganese-based oxide, a lithium-iron phosphate-based oxide, and a cobalt-free nickel-manganese-based oxide.

[0036] In each of the first active material layer (12) and the second active material layer (22), the binder may include at least one of an aqueous binder, a non-aqueous binder, and a dry binder. In each of the first active material layer (12) and the second active material layer (22), the conductive material may include at least one of a carbon-based material such as natural graphite, artificial graphite, carbon black, carbon fiber, carbon nanofiber, or carbon nanotube; a metal material in the form of metal powder or metal fiber including copper, nickel, aluminum, or silver; and a conductive polymer such as a polyphenylene derivative.

[0037] The separator (30) may be composed of a porous substrate or a porous substrate having a coating layer positioned on at least one surface. The porous substrate may include one or more of polyethylene, polypropylene, polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyester, polycarbonate, and polyimide. The coating layer may include a binder, and the binder may include a polyvinylidene fluoride-based compound. The separator (30) insulates the first electrode (10) and the second electrode (20) while allowing the movement of lithium ions.

[0038] In the first electrode (10), the first active material layer (12) may be positioned on the remaining portion except for one side (upper side) edge of the first substrate (11). The portion of the first substrate (11) that is not covered by the first active material layer (12) and has an exposed surface is referred to as a first non-coated portion (13). The first non-coated portion (13) may be referred to as a first substrate tab or a first electrode tab.

[0039] In the second electrode (20), the second active material layer (22) may be positioned on the remaining portion except for the other (lower) edge of the second substrate (21). The portion of the second substrate (21) that is not covered by the second active material layer (22) and has an exposed surface is referred to as a second non-coated portion (23). The second non-coated portion (23) may be referred to as a second substrate tab or a second electrode tab.

[0040] The first plain region (13) may include a pair of edge plain regions (131) and a central plain region (132) positioned between the pair of edge plain regions (131). The second plain region (23) may include a pair of edge plain regions (231) and a central plain region (232) positioned between the pair of edge plain regions (231). The heights of the edge plain regions (131, 231) measured along the width direction (W direction) of the first electrode (10) and the second electrode (20) may be smaller than the heights of the central plain regions (132, 232). Both sides of the central plain region (132, 232) may be diagonal, but are not limited to this example.

[0041] The central uncoated portion (132, 232) may be bent inward toward the winding center of the electrode assembly (130). A plurality of cutting lines may be positioned in the central uncoated portion (131, 232) to facilitate bending of the central uncoated portion (131, 232). The plurality of cutting lines may be formed in a diagonal direction, but are not limited to this example.

[0042] Referring to FIGS. 2 to 4, the first collector plate (160) may face one side (upper side) of the electrode assembly (130) and may be fixed to the central uncoated portion (132) of the first electrode (10) by a method such as welding. The central uncoated portion (132) may transmit the current of the first electrode (10) to the first collector plate (160). The second collector plate (170) may face the other side (lower side) of the electrode assembly (130) and may be fixed to the central uncoated portion (232) of the second electrode (20) by a method such as welding. The central uncoated portion (232) may transmit the current of the second electrode (20) to the second collector plate (170).

[0043] The central non-conductive portions (131, 132) that are folded inward and overlap each other can increase the current collection efficiency of the first electrode (10) and the second electrode (20). The electrode assembly (130) and the first current collecting plate (160) and the second current collecting plate (170) can be stored inside the case (120) together with the electrolyte.

[0044] A terminal hole may be located in the center of the bottom portion (121) of the case (120), and a terminal portion (140) may be installed in the terminal hole. The terminal portion (140) may include a first terminal (141) having a circular shape and a second terminal (142) having a roughly cylindrical shape. The first terminal (141) may be referred to as a terminal plate, and the second terminal (142) may be referred to as a rivet terminal. The first terminal (141) may be located on the outside of the bottom portion (121), and the second terminal (142) may be fitted into the terminal hole. The second terminal (142) may be connected to the first terminal (141) and the bottom portion (121) by riveting.

[0045] The second terminal (142) can be coupled to the second collector plate (170), and the terminal portion (140) can be charged with the same polarity as the second electrode (20) to function as a terminal (positive terminal) of the second electrode (20). The first insulator (181) can be positioned between the bottom portion (121) and the first terminal (141). The second insulator (182) can include a portion positioned between the second terminal (142) and the bottom portion (121), and a portion positioned between the bottom portion (121) and the second collector plate (170). A third insulator (183) can be additionally positioned between the second collector plate (170) and the second insulator (182). The first to third insulators (181, 182, 183) can insulate the case (120) and the terminal portion (140).

[0046] A beading portion (123) and a crimping portion (124) may be positioned on the side portion (122) of the case (120). The beading portion (123) may be a portion that is concavely deformed toward the inside of the case (120), and the crimping portion (124) may be a portion in which the upper end of the side portion (122) is bent toward the inside of the case (120). The electrode assembly (130) may be accommodated in the space between the bottom portion (121) and the beading portion (123), and shaking may be suppressed by the beading portion (123) inside the case (120).

[0047] The first collector plate (160) may include a disc-shaped body (161) and a plurality of connectors (162) extending upward from an edge of the body (161). The plurality of connectors (162) may be arranged at equal intervals along the circumference of the body (161). Each of the plurality of connectors (162) may be in contact with the beading portion (123) and may be fixed to the beading portion (123) by a method such as welding. The case (120) may be charged with the same polarity as the first electrode (10) by the first collector plate (160) and may function as a terminal (negative terminal) of the first electrode (10).

[0048] As another example, although the city is omitted, a first collector plate connected to a first electrode may be joined to a terminal portion, and a second collector plate connected to a second electrode may be secured to a bead portion with the aforementioned connector. In this case, the case may function as a positive terminal, and the terminal portion may function as a negative terminal.

[0049] The cap plate (150) may be positioned on the outer side (upper side) of the first collector plate (160), and the edge of the cap plate (150) may be fixed between the beading portion (123) and the crimping portion (124) via an insulating gasket (190). The cap plate (150) and the insulating gasket (190) may seal the case (120), and the cap plate (150) may be electrically non-polar by being insulated from the first electrode (10), the second electrode (20), and the case (120). The bonding structure of the side portion (122) and the insulating gasket (190) may have a major influence on the sealing performance of the case (120).

[0050] A notch groove (151) may be positioned on at least one surface of the cap plate (150). The notch groove (151) may have a V-shaped cross-section, and may be arc-shaped on the bottom surface (when the target object is viewed from below). The internal temperature of the secondary battery (100) may rise due to various reasons such as rapid charging and discharging, external impact, exposure to a high-temperature environment, etc., and the internal pressure may rise due to evaporation of the electrolyte, etc. When the internal pressure of the secondary battery (100) rises, the cap plate (150) may break from the notch groove (151), thereby releasing internal gas.

[0051] Fig. 5 is a partially enlarged view of the secondary battery illustrated in Fig. 2. Fig. 6 is a partially enlarged view of Fig. 5.

[0052] Referring to FIGS. 2, 5, and 6, the beading portion (123) may be generally composed of two straight portions and three curved portions in cross-section. For example, the two straight portions may include an upper portion (41) close to the crimping portion (124) and a lower portion (42) positioned toward the bottom portion (121). The three curved portions may include an upper curved portion (43) connecting the side portion (121) and the upper portion (41), an intermediate curved portion (44) connecting the upper portion (41) and the lower portion (42), and a lower curved portion (44) connecting the side portion (121) and the lower portion (42). The beading portion (123) may be manufactured by conventional press processing.

[0053] The upper portion (41) and the lower portion (42) may intersect the side portion (121). For example, the upper portion (41) may be perpendicular to the side portion (121) or may intersect the side portion (121) at an angle close to 90°. The lower portion (42) may be perpendicular to the side portion (121) or may intersect the side portion (121) at an angle close to 90°, or may be positioned at an angle inclined toward the bottom portion (121). In FIGS. 5 and 6, an example is shown where the upper portion (41) intersects the side portion (121) at an angle close to 90°, and the lower portion (42) is slightly inclined toward the bottom portion (121).

[0054] The upper portion (41) of the beading portion (123) may be a portion that supports the connector (162) of the first collector plate (160) and, together with the crimping portion (124), supports the insulating gasket (190). The upper portion (41) may be referred to as a support portion. For convenience, the upper portion (41) will be referred to as a 'support portion' hereinafter. In addition, the upper curved portion (43) of the beading portion (123) will be referred to as a 'beading curved portion' hereinafter for convenience.

[0055] The connector (162) may include a first connecting portion (51) that contacts the support portion (41), a second connecting portion (52) that contacts the beading curved portion (43), and a third connecting portion (53) that is positioned between the main body (161) and the first connecting portion (51). The first to third connecting portions (51, 52, 53) may be integrally formed and may be positioned in a row in the order of the third connecting portion (53), the first connecting portion (51), and the second connecting portion (52) from the main body (161).

[0056] The first connecting portion (51) may have the same angle as the support portion (41) with respect to the side portion (121) and may be in contact with the entire support portion (41). The second connecting portion (52) may have a curvature corresponding to the curvature of the beading curved portion (43) and may be in contact with at least a portion of the beading curved portion (43). For example, the second connecting portion (52) may be in contact with the entire beading curved portion (43). The first connecting portion (51) and the second connecting portion (52) may be in close contact with the support portion (41) and the beading curved portion (43) without lifting.

[0057] The third connecting portion (53) can be bent downward from the first connecting portion (51) toward the main body (161). The third connecting portion (53) can be composed of at least one bent portion (54) and two or more straight portions. For example, the third connecting portion (53) can include three bent portions (54) and four straight portions, but is not limited to this example. The third connecting portion (53) can absorb the external force when an external force is applied, causing deformation such that the angle of the bent portion (54) changes. In other words, the third connecting portion (53) can function as a type of plate spring.

[0058] The insulating gasket (190) can be divided into an upper portion (191) positioned between the crimping portion (124) and the cap plate (150), a middle portion (192) surrounded by the side portions (122), and a lower portion (193) positioned between the first and second connecting portions (51, 53) and the cap plate (150). The lower portion (193) of the insulating gasket (190) does not contact the support portion (41) and can be positioned on the support portion (41) with the first and second connecting portions (51, 52) interposed therebetween. That is, the first and second connecting portions (51, 52) of the connector (162) can be positioned between the support portion (41) and the lower portion (193) of the insulating gasket (190).

[0059] Fig. 7 is a partially enlarged cross-sectional view of a secondary battery according to a comparative example. Referring to Fig. 7, in the secondary battery of the comparative example, the edge of the connector (162a) may be positioned on the support (41). That is, the connector (162a) may contact a part of the support (41) rather than the entire support (41), and may be fixed to the support (41) at or near the edge of the connector (162a).

[0060] In the secondary battery of the comparative example, a part of the lower part (193a) of the insulating gasket (190a) may be in contact with the support (41), and the remaining part may be in contact with the connector (162a). At this time, a step is generated at the lower part of the insulating gasket (190a) due to the height difference between the support (41) and the connector (162a). That is, the lower part (193a) of the insulating gasket (190a) is divided into a lower part that is in contact with the support (41) and a higher part that is in contact with the connector (162a), and a height difference (step) is generated between them. Area B in Fig. 7 represents an area where a step occurs.

[0061] In the secondary battery of the comparative example, the insulating gasket (190a) is subjected to uneven pressure due to the step, and stress is concentrated at the step portion, which may cause cracks, etc., to occur in the insulating gasket (190a) when used for a long time. The uneven pressure distribution and stress concentration of the insulating gasket (190a) may lead to a deterioration in the sealing performance of the insulating gasket (190a).

[0062] Referring again to FIGS. 5 and 6, in the secondary battery (100) of the present embodiment, the connector (162) may include a first connecting portion (51) and a second connecting portion (52) that are in close contact with the support portion (41) and the beading curved portion (43). Accordingly, the lower portion (193) of the insulating gasket (190) may have a constant thickness without a step. As a result, the insulating gasket (190) may maintain a constant pressure distribution and prevent stress from being concentrated in a specific portion.

[0063] Specifically, the lower portion (193) of the insulating gasket (190) has a constant thickness, so that the same compression ratio is applied to the entire lower portion (193), and thus the force can be evenly distributed during compression. Accordingly, the insulating gasket (190) can stably exhibit sealing performance for a long period of time, thereby improving the durability of the secondary battery (100).

[0064] The connector (162) can be fixed to the beading portion (123) by a welding method such as laser welding. The welding method leaves a weld portion (60) called a weld bead. The weld portion (60) of the beading portion (123) and the connector (162) can be located between the second connecting portion (52) and the beading curved portion (43). In the secondary battery of the comparative example (see FIG. 7), the weld portion of the beading portion (123) and the connector (162a) is located between the support portion (41) and the edge of the connector (162a), whereas in the secondary battery (100) of the present embodiment, the weld portion (60) of the beading portion (123) and the connector (162) can be located between the second connecting portion (52) and the beading curved portion (43).

[0065] Typically, a clamping stress is applied to the weld of a bead portion and a connector, and the clamping stress may cause damage to the weld portion or deformation of surrounding components. In the secondary battery of the comparative example (see Fig. 7), the weld portion is located close to the step area (B) of the insulating gasket (190a). In the structure of the comparative example in which the weld portion vulnerable to damage and the step area (B) are located close to each other, at least one of the bead portion (123), the connector (162a), and the insulating gasket (190a) may be easily damaged or deformed.

[0066] In the secondary battery (100) of the present embodiment, the connector (162) is in close contact with the entire support portion (41) and the beading curved portion (43) to secure the maximum overlapping area with the beading portion (123), and the lower portion (193) of the insulating gasket (190) can maintain a constant thickness without a step. In addition, the welded portion (60) of the beading portion (123) and the connector (162) is located at the second connecting portion (52) closest to the side portion (122), and since this portion where the welded portion (60) is located is a portion that receives less compressive force than the portion where the welded portion is located in the secondary battery of the comparative example, damage to the welded portion (60) or deformation of surrounding components can be minimized compared to the comparative example.

[0067] Fig. 8 is a partially enlarged cross-sectional view of a secondary battery according to a second embodiment. The secondary battery of the second embodiment has a configuration identical or similar to that of the first embodiment described above, except for the configuration described below.

[0068] Referring to Fig. 8, in the secondary battery of the present embodiment, the welded portion of the beading portion (123) and the connector (162) may include a first welded portion (61) positioned between the second connecting portion (52) and the beading curved portion (43), and a second welded portion (62) positioned between the first connecting portion (51) and the support portion (41). The first welded portion (61) and the second welded portion (62) may be positioned at a distance from each other.

[0069] The second welded portion (62) can be manufactured by forging welding so as not to protrude above the support portion (41), and thus the lower portion (not shown) of the insulating gasket can maintain a constant thickness without a step. The connector (162) can secure a maximum overlapping area with the beaded portion (123) and be stably fixed to the beaded portion (123) by a plurality of welded portions (61, 62).

[0070] Fig. 9 is a partially enlarged cross-sectional view of a secondary battery according to a third embodiment. The secondary battery of the third embodiment has a configuration identical or similar to either the first or second embodiments described above, except for the configuration described below.

[0071] Referring to Fig. 9, in the secondary battery of the present embodiment, the connector (162) may include a first connector (70) coupled to the beading portion (123), and a second connector (80) connecting the main body (161) and the first connector (70). The first connector (70) and the second connector (80) may be manufactured separately and may be joined to each other by a method such as welding.

[0072] The first connector (70) may include a first connecting portion (51) that contacts the support portion (41), a second connecting portion (52) that contacts the beading curved portion (43), and an extension portion (55) that extends from the first connecting portion (51) toward the interior of the case (120). The extension portion (55) may be positioned in a floating state without overlapping the beading portion (123), and may be parallel to the first connecting portion (51).

[0073] The length of the extension portion (55) may be greater than the length of the first connecting portion (51), but is not limited to this example. In the present embodiment, the length refers to the length measured in the horizontal direction based on FIG. 9. The weld portion of the beading portion (123) and the connector (162) may be located between the second connecting portion (52) and the beading curved portion (43), and may additionally be located between the first connecting portion (51) and the support portion (41).

[0074] One end of the second connector (80) may be fixed to one side (bottom side) of the first connector (70) facing the main body (161), and the other end of the second connector (80) may be fixed to the main body (161). The second connector (80) may have at least one bending portion (54) and may have the same configuration as the third connecting portion (53) of the above-described embodiments. One end of the second connector (80) may be fixed between the first connecting portion (51) and the extension portion (55), or may be fixed to the extension portion (55).

[0075] Since the first connector (70) has the extension portion (55), the lower portion (193) of the insulating gasket (190) may have a longer length than in the embodiments described above. For example, the length of the lower portion (193) of the insulating gasket (190) may be longer than the length of the upper portion (191), and may be approximately twice the length of the upper portion (191). In addition, the length of the lower portion (193) of the insulating gasket (190) may be longer than the length of the first connector (70). For example, the edge of the lower portion (193) of the insulating gasket (190) may be positioned to protrude toward the inside (right side) of the extension portion (55).

[0076] The gasket (190) of the aforementioned configuration can improve the sealing function by its extended length and can more stably support the edge of the cap plate (150). In addition, even if deformation of the parts occurs due to external impact, the cap plate (150) and the connector (162) can be prevented from coming into contact with each other.

[0077] Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the patent claims, the detailed description of the invention, and the attached drawings, and it is obvious that this also falls within the scope of the present invention.

Claims

1. An electrode assembly including a first electrode, a separator, and a second electrode; A case including a bottom portion and a side portion connected to the bottom portion and having a beading portion and a crimping portion, and accommodating the electrode assembly; and A current collector plate having a main body fixed to one side of the electrode assembly and a connector extending from the main body toward the beading portion and contacting the beading portion, The above beading portion includes a support portion intersecting the side portion and facing the crimping portion, and a beading curved portion located between the side portion and the support portion, A secondary battery, wherein the connector comprises a first connecting portion that contacts the support portion and a second connecting portion that contacts the beading curved portion.

2. In paragraph 1, The first connecting portion has the same angle as the support portion with respect to the side portion and is placed in close contact with the support portion, A secondary battery in which the second connecting portion has a curvature corresponding to the beading curved portion and is placed in close contact with the beading curved portion.

3. In paragraph 1, The connector further includes a third connector positioned between the main body and the first connector, A secondary battery wherein the third connecting portion includes at least one bent portion and at least two straight portions.

4. In paragraph 1, The above connector, A first connector including the first connecting portion, the second connecting portion, and an extension portion extending from the first connecting portion toward the interior of the case; and A secondary battery including a second connector connecting the main body and the first connector.

5. In paragraph 4, The above extension portion is parallel to the first connecting portion, A secondary battery wherein the length of the above extension portion is greater than the length of the above first connecting portion.

6. In paragraph 4, One end of the second connector is fixed to one side of the first connector facing the main body, and the other end of the second connector is fixed to the main body. A secondary battery wherein the second connector includes at least one bent portion and at least two straight portions.

7. In paragraph 1, A secondary battery further comprising a weld portion positioned between the beading curved portion and the second connecting portion.

8. In paragraph 1, A first welding portion located between the beading curved portion and the second connecting portion; and A secondary battery further comprising a second welding portion positioned between the support portion and the first connecting portion.

9. In any one of paragraphs 1 to 8, It further includes a cap plate that is fixed between the beading portion and the crimping portion via an insulating gasket to seal the case, A secondary battery in which the above insulating gasket is maintained in a non-contact state with the beading portion by the above connector.

10. In paragraph 9, A secondary battery in which the portion of the insulating gasket located between the cap plate and the connector has a constant thickness.

11. Electrode assembly; A case comprising a bottom portion and a side portion connected to the bottom portion and having a beading portion and a crimping portion, and accommodating the electrode assembly; A cap plate that seals the case by being fixed between the beading portion and the crimping portion via an insulating gasket; and A current collector plate having a main body fixed to one side of the electrode assembly and a connector extending from the main body toward the beading portion and contacting the beading portion, The above beading portion includes a support portion intersecting the side portion and facing the crimping portion, and a beading curved portion located between the side portion and the support portion, The connector includes a first connecting portion that contacts the support portion and a second connecting portion that contacts the beading curved portion, A secondary battery in which the beading portion and the connector are fixed by a welding portion located between the beading curved portion and the second connecting portion.

12. In paragraph 11, A secondary battery in which the above insulating gasket is maintained in a non-contact state with the beading portion by the above connector.

13. In paragraph 12, A secondary battery in which the portion of the insulating gasket located between the cap plate and the connector has a constant thickness.

14. In paragraph 11, The connector further includes a third connector positioned between the main body and the first connector, A secondary battery wherein the third connecting portion includes at least one bent portion and at least two straight portions.

15. In paragraph 11, The above connector, A first connector including the first connecting portion, the second connecting portion, and an extension portion extending from the first connecting portion toward the interior of the case; and A secondary battery including a second connector connecting the main body and the first connector.

16. In paragraph 15, The above extension portion is parallel to the first connecting portion, A secondary battery wherein the length of the above extension portion is greater than the length of the above first connecting portion.

17. In paragraph 15, One end of the second connector is fixed to one side of the first connector facing the main body, and the other end of the second connector is fixed to the main body. A secondary battery wherein the second connector includes at least one bent portion and at least two straight portions.

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