Cylindrical secondary battery

Abstract

The present invention relates to a cylindrical secondary battery including: an electrode assembly provided with an electrode tab; a battery can accommodating the electrode assembly through an opening formed at one side; a cover plate covering the opening; a current collecting plate disposed between the electrode assembly and the cover plate and electrically connecting the electrode tab and the battery can; and a separator including a main body portion between the current collecting plate and the cover plate, a closing portion closing between the battery can and the cover plate, and a connecting portion connecting the main body portion and the closing portion. The current collecting plate can include: a center portion; a tab coupling portion expanding from the center portion toward an outer side and coupled with the electrode tab; a can coupling portion coupled with the battery can and having a height difference with the tab coupling portion; and a bridge portion connecting the center portion and the can coupling portion and extending obliquely toward a direction away from the electrode assembly as it is away from the center portion. The bridge portion of the current collecting plate and the connecting portion of the separator are disposed staggered so as not to overlap each other in a height direction of the battery can.

Description

Technical Field

[0001] This invention relates to cylindrical secondary batteries. Background Technology

[0002] Previous cylindrical secondary batteries typically had a structure in which tabs connecting the gel roll and external terminals were soldered to the foil of the gel roll to achieve the connection. This structure of cylindrical secondary batteries limited the current path, and the gel roll itself had very high resistance.

[0003] Therefore, an attempt was made to reduce the resistance by increasing the number of tabs connecting the gel roll and the external terminals. However, simply increasing the number of tabs has limitations in reducing the resistance to the desired level and ensuring a sufficient current path.

[0004] Therefore, in order to reduce the resistance of the gel roll itself, it is necessary to develop new gel roll structures and current collector structures suitable for such gel roll structures. In particular, the application of such new gel roll and current collector structures is even more necessary in devices such as electric vehicles that require battery packs with high output / high capacity.

[0005] Furthermore, considering the operating environment, battery packs used in electric vehicles and similar applications are inevitably exposed to vibration and shock frequently. Therefore, there is a need to develop cylindrical secondary batteries with a structure that minimizes the risk of damage to welded parts even when subjected to vibration and external impact, as well as current collector structures for such cylindrical secondary batteries. Summary of the Invention

[0006] Technical problems to be solved

[0007] One technical problem to be solved by the present invention is to provide a cylindrical secondary battery including a current collector plate with a structure suitable for electrode assemblies having a low resistance structure.

[0008] Another technical problem to be solved by the present invention is to provide a cylindrical secondary battery with a current collector plate having a structure that can significantly reduce the possibility of damage to the welded parts with the electrode assembly and / or the welded parts with the battery can even when subjected to vibration and impact.

[0009] means of solving technical problems

[0010] A cylindrical secondary battery according to an embodiment of the present invention may include: an electrode assembly having electrode tabs; a battery can housing the electrode assembly through an opening formed on one side; a cover plate covering the opening; a current collector plate disposed between the electrode assembly and the cover plate, and electrically connecting the electrode tabs and the battery can; and a separator including a main body portion located between the current collector plate and the cover plate, a closing portion for closing the space between the battery can and the cover plate, and a connecting portion connecting the main body portion and the closing portion. The current collector plate may include: a central portion; a tab connection portion extending outward from the central portion and engaging with the electrode tabs; a can connection portion engaging with the battery can and having a height difference with the tab connection portion; and a bridging portion connecting the central portion and the can connection portion, and extending obliquely away from the central portion in a direction away from the electrode assembly. The bridging portion of the current collector plate and the connecting portion of the separator are staggered so that they do not overlap each other in the height direction of the battery can.

[0011] In the circumferential direction of the aforementioned central part, the bridging portion and the tab joint portion can be alternately configured.

[0012] In the height direction of the battery can, the tab joint and the can joint may not overlap.

[0013] The aforementioned bridging portion can have a gentle inclination as it moves away from the aforementioned central portion.

[0014] The aforementioned can joint can extend along the inner circumference of the aforementioned battery can.

[0015] The width of the aforementioned tab joint can increase as it moves away from the aforementioned center portion.

[0016] The aforementioned tab joint may have at least one injection hole.

[0017] The aforementioned injection hole can be configured such that its width increases as it moves away from the aforementioned center.

[0018] In the radial direction of the aforementioned battery can, the distance from the central axis of the battery can to the outer edge of the can joint can be greater than the distance from the central axis of the battery can to the outer edge of the tab joint.

[0019] The outer edge of the aforementioned tab joint can be an arc shape with a first radius of curvature, and the outer edge of the aforementioned can joint can be an arc shape with a second radius of curvature larger than the first radius of curvature.

[0020] A rolled edge is formed from the periphery of the battery can toward the cover plate and the electrode assembly, and the can joint can be joined to the rolled edge.

[0021] The aforementioned cylindrical secondary battery may further include a closure portion that surrounds the periphery of the aforementioned cover plate. The aforementioned can joint portion can be secured by being sandwiched between the aforementioned closure portion and the aforementioned rolled edge portion.

[0022] The aforementioned can joint may include: an outer region that overlaps with the rolled edge in the height direction of the battery can; and an inner region located inside the outer region and connected to the bridging portion.

[0023] The aforementioned tab joint portion may not overlap with the aforementioned rolled edge portion in the height direction of the aforementioned battery can.

[0024] The distance from the central axis of the battery can to the outer edge of the tab joint can be more than 2 / 3 of the radius of the electrode assembly.

[0025] The height difference between the aforementioned tab joint and the aforementioned can joint can correspond to the height of the aforementioned rolled edge.

[0026] The bonding strength between the battery can and the can joint can be greater than the bonding strength between the electrode tab and the electrode tab joint.

[0027] A rolled edge is formed from the periphery of the battery can into the space between the cover plate and the electrode assembly, and the can joint can be welded to the flat area of ​​the rolled edge.

[0028] The weld beads formed at the joint of the aforementioned tank can be located on the inner side with an interval of more than 0.1 mm from the boundary of the aforementioned flat area.

[0029] The cover plate described above can be formed with a vent section having a thickness of less than 1 / 10 of the thickness of the cover plate described above.

[0030] The height of the main body can correspond to the distance between the current collector and the cover plate.

[0031] The main body can be without pressurizing the current collector.

[0032] The aforementioned closure covers the edge of the aforementioned cover plate and can insulate the aforementioned battery can from the aforementioned cover plate.

[0033] The distance between the connecting part and the cover plate can increase as it moves away from the main body.

[0034] Invention Effects

[0035] According to a preferred embodiment of the present invention, resistance can be significantly reduced when realizing the electrical connection between the electrode assembly and the battery canister.

[0036] Furthermore, even when vibration and impact are applied during the use of secondary batteries, the possibility of damage to the welded joints between the current collector and the electrode assembly, and / or the welded joints between the current collector and the battery canister, can be significantly reduced.

[0037] In addition, it may include effects that can be easily predicted by those skilled in the art from the configuration of the preferred embodiments of the present invention. Attached Figure Description

[0038] The following accompanying drawings, which schematically illustrate preferred embodiments of the invention, serve to further explain the technical concept of the invention together with the detailed description of the invention that follows, and should not be construed as limiting the invention to the matters shown in these drawings.

[0039] Figure 1 This is a perspective view of a cylindrical secondary battery according to an embodiment of the present invention.

[0040] Figure 2 This is a cross-sectional view of a cylindrical secondary battery according to an embodiment of the present invention.

[0041] Figure 3 It is shown in magnification Figure 2 The diagram shows a cross-sectional view of the first collector board and its surrounding area.

[0042] Figure 4 This is a perspective view of a first current collector according to an embodiment of the present invention.

[0043] Figure 5 This is a plan view of the first current collector according to an embodiment of the present invention.

[0044] Figure 6 It is aimed at Figure 5 A cross-sectional view of A-A'.

[0045] Figure 7 This is an enlarged cross-sectional view showing the state in which the first current collector is attached to the rolled edge portion according to an embodiment of the present invention.

[0046] Figure 8 This is a plan view showing the state in which the first current collector is attached to the rolled edge portion according to an embodiment of the present invention.

[0047] Figure 9 This is a perspective view of a cover plate and a spacer according to another embodiment of the present invention.

[0048] Explanation of reference numerals in the attached figures

[0049] 1: Cylindrical secondary battery; 10: Electrode assembly

[0050] 11: First electrode tab; 12: Second electrode tab

[0051] 20: Battery can 21: Curled edge

[0052] 21a: Flattened area; 22: Pressing part

[0053] 30: Cover plate 31: Plate section

[0054] 32: Inclined portion 33: Edge portion

[0055] 34: Ventilation section 40: Terminal

[0056] 50: First collector board; 51: Central section

[0057] 51a: Central hole; 52: Electrode junction

[0058] 52a: (outer edge of the tab junction)

[0059] 52b: (The two sides of the junction of the tabs)

[0060] 52c: Combination region 52d; Injection hole

[0061] 53: Tank joint 531: External area

[0062] 532: Internal region; 53a: Outer edge (of the tank joint)

[0063] 53b: (Inner edge of the can joint)

[0064] 53c: (Both sides of the can joint)

[0065] 53d: Solder ball; 54: Bridging section

[0066] 54a: First inclined section; 54b: Second inclined section

[0067] 60: Second collector plate; 70: Spacing plate

[0068] 71: Main body 72: Enclosed section

[0069] 73: Connecting part; 80: Insulator Detailed Implementation

[0070] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can readily implement the technical concept of the present invention. However, the present invention can be implemented in many different ways and is not limited to the embodiments described below.

[0071] To clearly illustrate the present invention, details of relevant prior art that are not related to the description or may obscure the spirit of the present invention have been omitted. When labeling each constituent element in the specification, the same or similar constituent elements are labeled with the same or similar reference numerals throughout the specification.

[0072] Furthermore, the terms and words used in this specification and claims should not be limited to their ordinary or dictionary meanings. Given the principle that inventors may appropriately define terms and concepts in order to best describe their invention, they should be interpreted as meanings and concepts consistent with the technical ideas of this invention.

[0073] Figure 1 This is a perspective view of a cylindrical secondary battery according to an embodiment of the present invention. Figure 2 This is a cross-sectional view of a cylindrical secondary battery according to an embodiment of the present invention.

[0074] A cylindrical secondary battery 1 (hereinafter referred to as "secondary battery") according to an embodiment of the present invention may include an electrode assembly 10 and a battery canister 20 for housing the electrode assembly 10.

[0075] The electrode assembly 10 may include a positive electrode, a negative electrode, and a separation membrane sandwiched between the positive and negative electrodes. Furthermore, the electrode assembly 10 may be provided with a first electrode tab 11 connected to either the positive or negative electrode, and a second electrode tab 12 connected to the other of the positive and negative electrodes.

[0076] More specifically, the electrode assembly 10 can be a jelly-roll type. The electrode assembly 10 can be manufactured by rolling up a laminate of a positive electrode, a separator membrane, a negative electrode, and another separator membrane sequentially. Preferably, the height-to-diameter ratio of the electrode assembly 10 is 1 or more, but it is not limited to this. The central portion of the electrode assembly 10 may have a hollow C-shaped portion that is elongated in the height direction. To insulate the electrode assembly 10 from the inner periphery of the battery canister 20, the separator membrane may be located at the outermost periphery of the electrode assembly 10.

[0077] The first electrode tab 11 and the second electrode tab 12 can be disposed at both ends of the electrode assembly 10 in the height direction. More specifically, the uncoated portion of either the positive or negative electrode can be located at one end of the electrode assembly 10, and can function as the first electrode tab 11. The uncoated portion of the other positive or negative electrode can be located at the other end of the electrode assembly 10, and can function as the second electrode tab 12.

[0078] Each electrode tab 11, 12 can extend along the winding direction of the electrode assembly 10.

[0079] Alternatively, each electrode tab 11, 12 may include multiple foil flags arranged along the winding direction of the electrode assembly 10.

[0080] The first electrode tab 11 can be coupled to the first current collector 50, which will be described later, and the second electrode tab 12 can be coupled to the second current collector 60, which will be described later. The electrode assembly 10 can be housed in the battery canister 20 with each electrode tab 11, 12 coupled to each current collector 50, 60.

[0081] For example, the first electrode tab 11 can be the uncoated portion of the negative electrode, and the second electrode tab 12 can be the uncoated portion of the positive electrode. In this case, the first current collector 50 can be named the negative current collector, and the second current collector 60 can be named the positive current collector.

[0082] The battery canister 20 can be generally cylindrical. One side of the battery canister 20 in the height direction can be provided with a surface 20a, and the other side can be formed with an open portion.

[0083] The electrode assembly 10 can be housed together with the electrolyte in the battery canister 20 through the aforementioned opening.

[0084] The battery canister 20 can be made of a conductive material such as metal. The battery canister 20 can be electrically connected to the first electrode tab 11 via the first current collector 50, which will be described later. The battery canister 20 can have the same polarity as the first electrode tab 11.

[0085] The battery canister 20 may have a beading portion 21 and a crimping portion 22. The beading portion 21 and the crimping portion 22 may be formed adjacent to the open portion of the battery canister 20.

[0086] The rolled edge 21 can be formed by pressing the periphery of the battery can 20 inwards towards the radius. The inner diameter of the rolled edge 21 can be smaller than the inner diameter of the battery can 20.

[0087] The rolled edge 21 can be formed while the electrode assembly 10 is housed within the battery can 20. The electrode assembly 10 can be confined between one side 20a of the battery can 20 and the rolled edge 21 in the height direction of the battery can 20. The rolled edge 21 prevents the electrode assembly 10 from detaching from the opening of the battery can 20. Furthermore, the rolled edge 21 can be coupled to the first current collector 50. For example, the first current collector 50 can be soldered to the rolled edge 21. Thus, the first current collector 50 can achieve an electrical connection between the first electrode tab 11 and the battery can 20.

[0088] The clamping portion 22 may be formed adjacent to the rolled edge portion 21. The clamping portion 22 may be formed by bending the end of the peripheral surface of the battery can 20 toward the radially inward side. The clamping portion 22 may be formed after the first current collector 50 is attached to the rolled edge portion 21. The clamping portion 22 and the rolled edge portion 21 may together restrict the cover plate 30, which will be described later.

[0089] The secondary battery 1 may include a cover 30 that covers the open portion of the battery canister 20.

[0090] The cover plate 30 can be in a generally circular shape. The cover plate 30, together with the battery canister 20, forms the appearance of the secondary battery 1. The edge of the cover plate 30 can be confined between the rolled edge 21 and the clamping part 22 of the battery canister 20.

[0091] The cover plate 30 can be made of a highly rigid material such as metal. The cover plate 30 can be insulated from the battery canister 20 and can be non-polarized. More specifically, the sealing portion 72 of the spacer 70, described later, can be sandwiched between the cover plate 30 and the battery canister 20. This will be described in detail later.

[0092] The secondary battery 1 may include a fixed terminal 40 that penetrates one side 20a of the battery canister 20.

[0093] Terminal 40 may penetrate one side 20a of battery can 20, and more specifically, may penetrate the central portion of the aforementioned side 20a. A portion of terminal 40 may protrude from the outside of battery can 20, while another portion may be located inside battery can 20. For example, terminal 40 may be riveted to one side 20a of battery can 20.

[0094] Terminal 40 can be made of a conductive material such as metal.

[0095] Terminal 40 can be combined with the second current collector 60, which will be described later. For example, the second current collector 60 can be soldered to terminal 40. Thus, the second current collector 60 realizes the electrical connection between the second electrode tab 12 and terminal 40.

[0096] Terminal 40 may be insulated from battery canister 20. More specifically, an insulating gasket G may be sandwiched between terminal 40 and battery canister 20. It should be noted that this is not a limitation; alternatively, an insulating coating may be formed on a portion of terminal 40, or terminal 40 and battery canister 20 may be separated from each other and terminal 40 may be structurally fixed.

[0097] The insulating gasket G deforms when the terminal 40 is riveted, allowing it to bend toward the inner surface of one side 20a of the battery can 20. The insulating gasket G can seal the gap between the terminal 40 and the battery can 20.

[0098] Through the insulating pad G, the battery canister 20 and the terminal 40 can have opposite polarities. More specifically, the battery canister 20 can have the same polarity as the first electrode tab 11, and the terminal 40 can have the same polarity as the second electrode tab 12. Therefore, one side 2a of the battery canister 20 can function as a first terminal with the first polarity, and the terminal 40 can function as a second terminal with the second polarity. Since one side 2a of the battery canister 20 and the terminal 40 are arranged adjacent to each other, the internal space required for the busbar can be reduced within the battery module including multiple secondary batteries 1, and the energy density of the battery module can be increased.

[0099] The secondary battery 1 may include a first current collector 50 that enables the electrical connection between the first electrode tab 11 and the battery canister 20. For example, the first electrode tab 11 may be connected to the negative electrode of the electrode assembly 10, and the first current collector 50 may be named the negative electrode current collector.

[0100] The secondary battery 1 may include a second current collector 60 that enables the electrical connection between the second electrode tab 11 and the terminal 40. For example, the second electrode tab 12 may be connected to the positive terminal of the electrode assembly 10, and the second current collector 60 may be named the positive current collector.

[0101] The first collector board 50 and the second collector board 60 can be located inside the battery canister 20.

[0102] The first current collector 50 can be located between the electrode assembly 10 and the cover plate 30 in the height direction of the battery can 20. The first current collector 50 can be combined with the first electrode tab 11. More specifically, the first current collector 50 can be welded to the first electrode tab 11. Furthermore, the first current collector 50 can be welded to the battery can 20, and more specifically, to the rolled edge portion 21.

[0103] The second current collector 60 can be located between the electrode assembly 10 and one side 20a of the battery can 20 in the height direction of the battery can 20. The second current collector 60 can be coupled to the second electrode tab 12. More specifically, the second current collector 60 can be soldered to the second electrode tab 12. Furthermore, the second current collector 60 can be soldered to the terminal 40.

[0104] The secondary battery 1 may include a separator 70 located between the cover plate 30 and the electrode assembly 10. More specifically, the separator 70 may be located between the cover plate 30 and the first current collector 50.

[0105] The height of the spacer 70 can correspond to the distance between the cover plate 30 and the electrode assembly 10. The spacer 70 can prevent the electrode assembly 10 from moving or shaking within the battery canister 20.

[0106] The secondary battery 1 may include an insulator 80 located between the electrode assembly 10 and the battery canister 20. More specifically, the insulator 80 may be located between the second current collector 60 and the battery canister 20.

[0107] The insulator 80 can insulate the second current collector 60 and the electrode assembly 10 from the battery canister 20. The insulator 80 can be made of an insulating resin material.

[0108] A hole may be formed in the central portion of the insulator 80 for the terminal 40 to pass through. Through the hole, the terminal 40 can be connected to the second current collector 60.

[0109] The insulator 80 may have a generally cap-shaped design. In this case, a portion of the insulator 80 may be located between one side 20a of the battery can 20 and the second current collector 60, and another portion may be located between the outer periphery of the second current collector 60 and the inner periphery of the battery can 20.

[0110] It should be noted that this is not a limitation; the insulator 80 may also have a plate shape located between one side 20a of the battery can 20 and the second current collector 60. In this case, an insulating tape separate from the insulator 80 may be sandwiched between the outer periphery of the second current collector 60 and the inner periphery of the battery can 20.

[0111] The height of the insulator 80 can correspond to the vertical distance between one side 20a of the battery can 20 and the electrode assembly 10. The insulator 80, together with the spacer 70, can prevent the electrode assembly 10 from moving or shaking within the battery can 20.

[0112] Figure 3 It is shown in magnification Figure 2 The diagram shows a cross-sectional view of the first current collector and its surrounding area. Figure 4 This is a perspective view of a first current collector according to an embodiment of the present invention. Figure 5 This is a plan view of the first current collector according to an embodiment of the present invention. Figure 6 It is aimed at Figure 5 A cross-sectional view of A-A'.

[0113] Below, refer to Figures 3 to 6 The first collector board 50 will be described.

[0114] As described above, the first current collector 50 can be coupled to the first electrode tab 11. More specifically, at least a portion of the first electrode tab 11 can be bent toward the hollow C of the electrode assembly 10, and the first current collector 50 can be coupled to the bent portion of the first electrode tab 11.

[0115] Therefore, reducing the height of the first electrode tab 11 can increase the energy density of the secondary battery 1. Furthermore, the increased bonding area between the first electrode tab 11 and the first current collector 50 improves the bonding force between them and reduces resistance.

[0116] More specifically, the first current collector 50 may include a central portion 51, a tab connection portion 52 extending outward from the central portion 51 and engaging with the first electrode tab 11, a can connection portion 53 engaging with the battery can 20 and separate from the tab connection portion 52, and a bridging portion 54 connecting the can connection portion 53 and the central portion 51.

[0117] The central portion 51 may be located at the center of one side (e.g., the lower side) of the electrode assembly 10. The central portion 51 may have a central hole 51a. The central hole 51a may face the hollow portion C of the electrode assembly 10. The central hole 51a, together with the hollow portion C, can function as a channel for inserting a welding rod for bonding the terminal 40 to the second current collector 60 or for irradiating a laser. Furthermore, the central hole 51a can also function as a channel for allowing the electrolyte to smoothly impregnate the interior of the electrode assembly 10 during electrolyte injection.

[0118] The tab connection portion 52 can extend outward from the center portion 51. The tab connection portion 52 can be connected to the first electrode tab 11. Multiple tab connections 52 can be provided, and multiple tab connections 52 can extend radially from the center portion 51.

[0119] The width of the tab joint 52 can increase as it moves away from the center 51. As a result, the tab joint 52 can cover a large area of ​​the bent portion of the first electrode tab 11, preventing the bent portion of the first electrode tab 11 from warping.

[0120] The central axes of the electrode assembly 10, the battery canister 20, and the first current collector 50 can be approximately aligned. In the radial direction of the battery canister 20, the distance R1 from the central axis of the battery canister 20 to the outer edge 52a of the tab joint 52 can be less than the radius Ra of the electrode assembly 10, and can be less than the inner radius Rb of the rolled edge 21.

[0121] More specifically, the outer edge 52a of the tab connection 52 can be an arc shape with a first radius of curvature R1. The center of curvature of the outer edge 52a can coincide with the center of the first collector plate 50.

[0122] The aforementioned first radius of curvature R1 can be smaller than the radius Ra of the electrode assembly 10. Furthermore, the aforementioned first radius of curvature R1 can be less than the inner radius Rb of the rolled edge portion 21 formed in the battery can 20.

[0123] The tab connection portion 52 may not overlap with the rolled edge portion 21 in the height direction of the battery can 20. That is, the tab connection portion 52 may not be located between the electrode assembly 10 and the rolled edge portion 21. This prevents the tab connection portion 52 from being damaged due to being sandwiched between the electrode assembly 10 and the rolled edge portion 21 during the sizing process. Sizing can refer to a compression process that reduces the height of the rolled edge portion 21 in order to reduce the height of the secondary battery 1 after the rolled edge portion 21 and the clamping portion 22 are formed in the battery can 20 containing the electrode assembly 10.

[0124] The distance R1 from the central axis of the battery canister 20 to the outer edge 52a of the tab joint 52 can be more than 2 / 3 of the radius Ra of the electrode assembly 10. More specifically, the first radius of curvature R1 can be more than 2 / 3 of the radius Ra of the electrode assembly 10. This ensures a sufficiently wide contact area between the electrode tab 11 of the electrode assembly 10 and the tab joint 52.

[0125] The two side edges 52b of the tab junction 52 can be formed along the radial direction of the first collector plate 50. An imaginary line extending along the two side edges 52b can pass through the center of the first collector plate 50.

[0126] The tab junction 52 may have an injection hole 52d. The injection hole 52d can improve the impregnation of the electrolyte for the electrode assembly 10.

[0127] The aforementioned injection hole 52d can be located outside the bonding region 52c in the tab bonding portion 52 that bonds with the first electrode tab 11. For example, the tab bonding portion 52 can have a pair of injection holes 52d, which can be formed across the bonding region 52c. In this case, the width W of the bonding region 52c can be constant. The pair of injection holes 52d can have a shape that is symmetrical to each other with respect to the bonding region 52c.

[0128] The width of the injection hole 52d can increase as it moves away from the center 51. As a result, the electrolyte can be more uniformly impregnated for the electrode assembly 10, which has a longer winding length per unit angle as it moves outward toward the radius.

[0129] The can joint 53 can be joined to the battery can 20, and more specifically, it can be joined to the rolled edge 21. The can joint 53 can be joined to the side of the rolled edge 21 that is relatively far from the electrode assembly 10.

[0130] The can joint 53 may have a predetermined height difference H relative to the center portion 51 and the tab joint portion 52. This height difference H may represent the distance between the tab joint portion 52 and the can joint portion 53 in the height direction of the battery can 20. This height difference H may correspond to the height of the rolled edge portion 21. That is, in the height direction of the battery can 20, the distance between the tab joint portion 52 and the can joint 53 may be the same as or similar to the height of the rolled edge portion 21.

[0131] The can joint 53 can be pressed by the closing part 72, which will be described later. More specifically, the can joint 53 can be fixed by being clamped between the closing part 72 and the rolled edge part 21.

[0132] The can joint 53 can be separated from the tab joint 52. More specifically, the can joint 53 and the tab joint 52 are only connected to the central portion 51, and the can joint 53 and the tab joint 52 are not directly connected to each other. As a result, when the secondary battery 1 is subjected to impact or vibration, the stress acting on the joint area between the tab joint 52 and the first electrode tab 11 and the joint area between the can joint 53 and the battery can 20 is dispersed, so the possibility of damage to the first current collector 50 can be minimized.

[0133] Multiple can joints 53 may be provided. In the circumferential direction of the first current collector 50, can joints 53 and tab joints 52 may be alternately arranged.

[0134] The can joint portion 53 can extend along the inner circumference of the battery can 20. That is, the can joint portion 53 can extend in the circumferential direction of the rolled edge portion 21. This increases the contact area between the can joint portion 53 and the rolled edge portion 21, so that the joint between the can joint portion 53 and the rolled edge portion 21 can be stably achieved, and the resistance between the can joint portion 53 and the rolled edge portion 21 can be reduced.

[0135] In the radial direction of the battery can 20, the distance R2 from the central axis of the battery can 20 to the outer edge 53a of the can joint 53 can be greater than the distance R1 from the central axis of the battery can 20 to the outer edge 52a of the tab joint 52. Furthermore, in the radial direction of the battery can 20, the distance R3 from the central axis of the battery can 20 to the inner edge 53b of the can joint 53 can be smaller than the distance R2 from the central axis of the battery can 20 to the outer edge 53a of the can joint 53.

[0136] More specifically, the outer edge 53a of the can joint 53 may be an arc shape with a second radius of curvature R2 that is larger than the first radius of curvature R1 described above. Furthermore, the inner edge 53a of the can joint 53 may be an arc shape with a third radius of curvature R3 that is smaller than the second radius of curvature R2. The centers of curvature of the outer edge 53a and the inner edge 53b of the can joint 53 may be approximately aligned with the central axis of the battery can 20.

[0137] The second radius of curvature R2 can be larger than the inner radius Rb of the rolled edge portion 21 formed in the battery can 20, and the third radius of curvature R3 can be smaller than the inner radius Rb of the rolled edge portion 21. That is, in the radial direction of the battery can 20, the distance R2 from the central axis of the battery can 20 to the outer edge 53a of the can joint portion 53 can be larger than the inner radius Rb of the rolled edge portion 21, and the distance R3 from the central axis of the battery can 20 to the inner edge 53b of the can joint portion 53 can be smaller than the inner radius Rb of the rolled edge portion 21.

[0138] If the second radius of curvature R2 is less than the inner radius Rb of the rolled edge portion 21, the can joint portion 53 may be difficult to join to the rolled edge portion 21. If the third radius of curvature R3 is greater than the inner radius Rb of the rolled edge portion 21, interference may occur between the bridging portion 54 (described later) and the rolled edge portion 21.

[0139] The two side edges 53c of the can joint 53 can be formed along the radial direction of the first current collector 50. An imaginary line extending along the two side edges 53c can pass through the center of the first current collector 50.

[0140] The can joint 53 and the tab joint 52 can be non-overlapping in the height direction of the battery can 20. Therefore, when multiple first current collectors 50 are loaded in the state before being coupled to the electrode assembly 10, it is possible to prevent interference between the can joint 53 of any one first current collector 50 and the tab joint 52 of another first current collector 50.

[0141] The bonding strength between the can joint 53 and the battery can 20, and more specifically, the bonding strength between the can joint 53 and the rolled edge portion 21, can be greater than the bonding strength between the electrode tab joint 52 and the first electrode tab 11. Therefore, the can joint 53 can be stably bonded to the battery can 20, which is a rigid body.

[0142] The bridging portion 54 can connect the can joint portion 53 and the center portion 51. The bridging portion 54 can extend outward from the center portion 51 in the radial direction and can be separated from the tab joint portion 52 in the circumferential direction of the first current collector 50.

[0143] Similar to the can joint 53, multiple bridging portions 54 may be provided, and the multiple bridging portions 54 may extend radially from the center portion 51. In the circumferential direction of the first current collector 50, the bridging portions 54 and the tab joints 52 may be arranged alternately.

[0144] There is a height difference H between the central portion 51 and the can joint portion 53, so the bridging portion 54 can be formed at an angle. The bridging portion 54 can be formed to extend at an angle away from the central portion 51 and away from the electrode assembly 10.

[0145] The inclination of the bridging portion 54 can become gentler as it moves away from the center portion 51. More specifically, the bridging portion 54 may include a first inclined portion 54a extending from the center portion 51 and a second inclined portion 54b extending from the first inclined portion 54a and having an inclination gentler than that of the first inclined portion 54a.

[0146] Relative to a horizontal plane orthogonal to the height direction of the battery can 20, the first inclined portion 54a can form a first angle a1, and the second inclined portion 54b can form a second angle a2 that is smaller than the first angle a1.

[0147] It should be noted that this is not the only limitation; the bridging portion 54 can also form a rounded corner as it moves away from the center portion 51 in a gentler direction.

[0148] Therefore, it is possible to prevent the bridging portion 54 from being excessively deformed during the sizing process, and to prevent the center portion 51 and the first electrode tab 11 attached to the center portion 51 from warping. During the sizing process, the rolled edge portion 21 is compressed towards the electrode assembly 10, resulting in a decrease in height. Therefore, the tab attachment portion 53 attached to the rolled edge portion 21 may also move towards the electrode assembly 10. As a result, the center portion 51, which is connected to the tab attachment portion 53 via the bridging portion 54, will be subjected to a rebound force in a direction away from the electrode assembly 10. If the inclination of the bridging portion 54 is constant or is formed to become steeper away from the center portion 51, the aforementioned rebound force will be greater on the center portion 51, and the center portion 51 and the first electrode tab 11 attached to it may warp. Conversely, the bridging portion 54 according to this embodiment can minimize the warping of the center portion 51 and the first electrode tab 11 caused by the sizing process.

[0149] Furthermore, the process of pressing the rolled edge 21 into the outer periphery of the battery can 20 in order to form the rolled edge 21 can be performed while the electrode assembly 10, which is attached to the first current collector 50, is housed inside the battery can 20. In this process, the bridging portion 54 has a gentle inclination as it moves away from the center portion 51, so it is easy to form the rolled edge 21 without interfering with the bridging portion 54.

[0150] Figure 7This is an enlarged cross-sectional view showing the state in which the first current collector is attached to the rolled edge portion according to an embodiment of the present invention. Figure 8 This is a plan view showing the state in which the first current collector is attached to the rolled edge portion according to an embodiment of the present invention.

[0151] The connection between the can joint 53 of the first collector plate 50 and the rolled edge 20 can form a clamping part 22 in the battery can 20 (see reference). Figure 3 (This should be done before)

[0152] The can joint 53 may include an outer region 531 that overlaps with the rolled edge 21 in the height direction of the battery can 20, and an inner region 532 located inside the outer region 531. That is, a portion of the inner side of the can joint 53 may not overlap with the rolled edge 21 in the height direction of the battery can 20. The inner region 532 is connected to the bridging portion 54 described above, so the possibility of interference between the rolled edge 21 and the bridging portion 54 can be minimized.

[0153] On the other hand, the can joint 53 can be welded to the flat area 21a on the rolled edge 21. That is, the welding bead 53d formed on the can joint 53 can be located on the flat area 21a.

[0154] The weld bead 53d can be formed to be relatively long along the circumferential direction of the rolled edge portion 21. Each can joint portion 53 can have at least one weld bead 53d formed thereon.

[0155] When forming the rolled edge 21, the portion connecting the periphery of the battery can 20 and the rolled edge 21 can be rounded. Therefore, the flat area 21a can be separated from the inner periphery of the battery can 20 in the direction of its radius.

[0156] The welding position of the can joint 53 relative to the flat area 21a can be separated from the boundary of the flat area 21a. That is, the weld beads 53d formed in the can joint 53 can be formed on the inner side at a predetermined interval from the boundary of the flat area 21a. Preferably, the weld beads 53d can be formed on the inner side at an interval of 0.1 mm or more from the boundary of the flat area 21a. For example, with the outer periphery of the battery can 20 as a reference, the distance d1 to the outer boundary of the flat area 21a can be 1.95 mm, and the distance d2 to the inner boundary of the flat area 21a can be 3.15 mm. In this case, with the outer periphery of the battery can 20 as a reference, the position of the weld beads 53d can be located in the region of 2.05 mm to 3.05 mm.

[0157] This eliminates concerns that the weld beads 53d of the can joint 53 may cross the boundary of the flat area 21a, and the can joint 53 can be stably welded to the flat area 21a.

[0158] Figure 9 This is a perspective view of the cover plate and the partition plate according to another embodiment of the present invention.

[0159] Below, refer to Figure 3 as well as Figure 9 The cover plate 30 and the partition plate 70 are described below.

[0160] The cover plate 30 may include a plate portion 31, an inclined portion 32 that expands and slopes outward from the periphery of the plate portion 31, and an edge portion 33 that expands outward from the inclined portion 32. The plate portion 31, the inclined portion 32, and the edge portion 33 may be integrally formed.

[0161] The plate portion 31 may have a generally flat circular plate shape. The inclined portion 32 may be formed to tilt in the direction of approaching the electrode assembly 10 as it moves away from the plate portion 31.

[0162] The edge portion 33 may be substantially parallel to the plate portion 31 and may have a predetermined height difference with the plate portion 31. More specifically, in the height direction of the battery can 20, the distance from the electrode assembly 10 to the plate portion 31 may be greater than the distance from the electrode assembly 10 to the edge portion 31.

[0163] The edge portion 33 can be located between the rolled edge portion 21 and the clamping portion 22 of the battery can 20. The edge portion 33 can be fixed by the closing portion 72 described later.

[0164] Therefore, compared to the case where the entire cover plate 30 is formed as a flat surface, the rigidity of the cover plate 30 can be improved.

[0165] The cover plate 30 may have a vent 34. More specifically, a vent 31 may be formed in the plate portion 31 of the cover plate 30.

[0166] The vent 34 can be formed to have a thinner thickness than the plate 31. As a result, the vent 34 can be structurally more fragile than the surrounding area, and the vent 34 can break first when the internal pressure of the battery tank 20 increases to a predetermined value.

[0167] The vent 34 can be formed along the circumference of the cover plate 30. For example, the vent 34 can be formed into a closed-loop shape such as a ring. Therefore, when the vent 34 breaks, the area inside the vent 34 in the cover plate 30 can easily separate to form an opening, allowing gas in the battery canister 20 to be quickly discharged.

[0168] If the internal pressure of the battery canister 20 is the same, the wider the area inside the vent 34 in the cover plate 30, the greater the force applied to the vent 34 can be. Therefore, in order to make the vent 34 break quickly, the vent 34 can be formed closer to the inclined portion 32 than the center of the plate portion 31. Preferably, the vent 31 can be formed adjacent to the inclined portion 32.

[0169] The thickness t2 of the vent 34 can be less than 1 / 10 of the thickness t1 of the cover plate 30 or, more specifically, the floor plate 31. If the thickness t2 of the vent 34 is greater than 1 / 10 of the thickness t1 of the plate plate 31, it may not be easy to break the vent 34.

[0170] The vent 34 can be formed by reducing the local thickness of the cover plate 30 by notching both sides of the cover plate 30 to a predetermined depth. When notching is performed only on one side of the cover plate 30, the shape of the cover plate 30 may be deformed.

[0171] The center of the cover plate 30 can be aligned with the central axis of the battery canister 20. When the vent 31 is formed along the circumference of the cover plate 30, the distance from the center of the cover plate 30 to the vent 31 can be the radius of curvature Rc of the closed curve formed by the vent 31.

[0172] A portion of the vent 34 may overlap with the tab engagement portion 52 of the first current collector plate 50 in the height direction of the battery can 20. More specifically, with reference to the central axis of the battery can 20, the distance R1 to the outer edge 52a of the tab engagement portion 52 of the first current collector plate 50 may be greater than the distance Rc to the vent 34 of the cover plate 30. That is, the first radius of curvature R1 may be greater than the radius of curvature Rc of the vent 31. This is to ensure that the tab engagement portion 52 has a sufficiently large contact area with the first electrode tab 11.

[0173] The cover plate 30 may not protrude from the battery canister 20. For example, when the cover plate 30 is located at the lower end of the battery canister 20, the bottom surface of the plate portion 31 of the cover plate 30 may be on the same surface as or above the bottom surface of the battery canister 20. Therefore, the cover plate 30 will not be pressed upwards by the bottom surface supporting the battery canister 20, preventing the pressure required for the vent 34 to break from deviating from the design value due to the weight of the secondary battery 1.

[0174] On the other hand, the separator 70 prevents the electrode assembly 10 from shaking or moving, thereby enhancing the sealing of the battery canister 20. In order to effectively absorb the impact or shaking applied to the secondary battery 1, the separator 70 may be made of an elastic material.

[0175] More specifically, the separator 70 may include a main body 71 located between the first current collector 50 and the cover plate 30, a sealing part 72 that seals the space between the battery canister 20 and the cover plate 30, and a connecting part 73 that connects the main body 71 and the sealing part 72. The main body 71, the sealing part 72, and the connecting part 73 may be integrally formed.

[0176] The main body 71 can be located at the center of the generally electrode assembly 10, separated by the first current collector 50. The main body 71 can face the first current collector 50, and more specifically, it can face the center portion 51.

[0177] The main body 71 may have a spacer hole 71a that faces the hollow C of the electrode assembly 10 through the central hole 51a of the first current collector 50. The spacer hole 71a, together with the central hole 51a and the hollow C, can function as a channel for inserting a welding rod or for irradiating a laser. Furthermore, the spacer hole 71a can function as a channel for allowing electrolyte to smoothly impregnate the interior of the electrode assembly 10.

[0178] The height of the main body 71 can correspond to the distance between the first current collector 50 and the cover plate 30. In this case, the main body 71 can effectively prevent the electrode assembly 10 from moving within the battery canister 20 due to the gap formed between the first current collector 50 and the cover plate 30. Therefore, the main body 71 can prevent damage to the joint between the electrode assembly 10 and the first current collector 50 and / or the joint between the first current collector 50 and the battery canister 20.

[0179] Before the sizing process, the distance between the first current collector 50 and the cover plate 30 can be greater than the height of the main body 71. Through the sizing process, the height of the rolled edge 21 is reduced, so the distance between the first current collector 50 and the cover plate 30 can be the same as or similar to the height of the main body 71. Therefore, the main body 71 does not elastically deform between the cover plate 30 and the first current collector 50, and the main body 71 does not need to apply pressure to the first current collector 50. This prevents damage to the first current collector 50 caused by the spacer 70.

[0180] The sealing portion 72 can be a circular ring extending along the inner circumference of the battery can 20. The sealing portion 72 can be fixed between the rolled edge portion 21 and the clamping portion 22 of the battery can 20. A portion of the sealing portion 72 can be bent together with the clamping portion 22 to fix the cover plate 30, further fixing the edge portion 33. Thus, the sealing portion 72 can securely seal the cover plate 30 and the battery can 20. In this way, the sealing portion 72 can function as a gasket to increase the fixing force of the cover plate 30 and improve the sealing performance of the battery can 20.

[0181] The sealing portion 72 presses against the can joint portion 53 of the first current collector 50 toward the rolled edge portion 21, thereby further strengthening the connection between the can joint portion 53 and the rolled edge portion 21. Furthermore, the sealing portion 72 can achieve insulation between the can joint portion 53 and the cover plate 30.

[0182] The connecting portion 73 can connect the main body 71 and the sealing portion 72. Multiple connecting portions 73 can be provided, extending radially from the main body 71 to the sealing portion 72. Electrolyte injection can be smoothly achieved through the space between the multiple connecting portions 73. Furthermore, when the vent 34 breaks due to the increase in internal pressure of the battery tank 20, the gas inside the battery tank 20 can be smoothly discharged through the space between the multiple connecting portions 73.

[0183] The distance between the connecting portion 73 and the cover plate 30 can increase as it moves away from the main body portion 71. More specifically, in the height direction of the battery can 20, the distance between the connecting portion 73 and the plate portion 31 of the cover plate 30 can increase as it moves outward in a radial direction toward the battery can 20.

[0184] Therefore, the deformation of the connecting portion 73 of the separator 70 caused by applying a compressive force in the height direction to the battery can 20 during the sizing process can be minimized, and even if deformation occurs, the interference with the cover plate 30 can be minimized.

[0185] The connecting portion 73 may not overlap with the bridging portion 54 of the first current collector 50 in the height direction of the battery can 20. The connecting portion 73 may overlap with the tab connection portion 52 of the first current collector 50 in the height direction of the battery can 20.

[0186] More specifically, the plurality of bridging portions 54 of the first current collector 50 and the plurality of connecting portions 73 of the spacer 70 can be staggered so that they do not overlap each other in the height direction of the battery canister 20. That is, the plurality of bridging portions 54 and the plurality of connecting portions 73 can be arranged alternately in the circumferential direction.

[0187] Therefore, when a compressive force in the height direction is applied to the battery canister 20 during the sizing process, causing deformation of the connecting portion 73 of the separator 70 and the bridging portion 54 of the first current collector 50, interference between the connecting portion 73 and the bridging portion 54 can be prevented.

[0188] The above description is merely an illustrative illustration of the technical concept of the present invention. Those skilled in the art to which this invention pertains can make various modifications and variations without departing from the essential characteristics of the present invention.

[0189] Therefore, the various embodiments disclosed in this invention are used to illustrate the technical concept of the invention and are not intended to limit the technical concept of the invention. The scope of the technical concept of the invention is not limited to these embodiments.

[0190] The scope of protection of this invention should be interpreted based on the claims, which can be interpreted as including all technical ideas within the same scope as those claims.

Claims

1. A cylindrical secondary battery, characterized in that, It includes: Electrode assembly, which is provided with electrode tabs; A battery can housing the aforementioned electrode assembly through an opening formed on one side; A cover plate that covers the aforementioned open portion; A current collector, disposed between the electrode assembly and the cover plate, electrically connects the electrode tabs and the battery canister; and The separator includes a main body located between the current collector and the cover plate, a sealing part that seals the space between the battery can and the cover plate, and a connecting part that connects the main body and the sealing part. The aforementioned current collector includes: Central part; The electrode tab connection portion expands outward from the aforementioned central portion and connects with the aforementioned electrode tab; The can joint portion, which is joined to the aforementioned battery can, and has a height difference with the aforementioned electrode tab joint portion; and The bridging portion connects the central portion and the can joint portion, and extends at an angle away from the central portion and away from the electrode assembly. The bridging portion of the current collector and the connecting portion of the spacer are staggered so that they do not overlap each other in the height direction of the battery can.

2. The cylindrical secondary battery according to claim 1, characterized in that, Along the circumference of the aforementioned central portion, the bridging portion and the tab joint portion are alternately arranged.

3. The cylindrical secondary battery according to claim 1, characterized in that, In the height direction of the battery can, the tab joint and the can joint do not overlap.

4. The cylindrical secondary battery according to claim 1, characterized in that, The aforementioned bridging portion has a gentle inclination as it moves away from the aforementioned central portion.

5. The cylindrical secondary battery according to claim 1, characterized in that, The aforementioned can joint extends along the inner circumference of the aforementioned battery can.

6. The cylindrical secondary battery according to claim 1, characterized in that, The width of the aforementioned tab joint increases as it moves away from the aforementioned center portion.

7. The cylindrical secondary battery according to claim 1, characterized in that, The aforementioned tab joint has at least one injection hole.

8. The cylindrical secondary battery according to claim 7, characterized in that, The aforementioned injection hole is formed such that its width increases as it moves away from the aforementioned center portion.

9. The cylindrical secondary battery according to claim 1, characterized in that, In the radial direction of the aforementioned battery can, the distance from the central axis of the aforementioned battery can to the outer edge of the aforementioned can joint is greater than the distance from the central axis of the aforementioned battery can to the outer edge of the aforementioned tab joint.

10. The cylindrical secondary battery according to claim 1, characterized in that, The outer edge of the aforementioned tab joint is an arc shape with a first radius of curvature. The outer edge of the aforementioned can joint is an arc shape with a second radius of curvature that is larger than the first radius of curvature.

11. The cylindrical secondary battery according to claim 1, characterized in that, A rolled edge is formed, pressing inward from the periphery of the battery can towards the space between the cover plate and the electrode assembly. The aforementioned can joint is joined to the aforementioned rolled edge.

12. The cylindrical secondary battery according to claim 11, characterized in that, Also includes: The closure section surrounds the aforementioned cover plate. The aforementioned can joint is fixed between the aforementioned closed portion and the aforementioned rolled edge portion.

13. The cylindrical secondary battery according to claim 11, characterized in that, The aforementioned tank joint includes: The outer region overlaps with the rolled edge portion in the height direction of the aforementioned battery can; and The inner region is located inside the aforementioned outer region and is connected to the aforementioned bridging portion.

14. The cylindrical secondary battery according to claim 11, characterized in that, The aforementioned tab joint does not overlap with the aforementioned rolled edge portion in the height direction of the aforementioned battery can.

15. The cylindrical secondary battery according to claim 11, characterized in that, The distance from the central axis of the battery can to the outer edge of the tab joint is more than 2 / 3 of the radius of the electrode assembly.

16. The cylindrical secondary battery according to claim 11, characterized in that, The height difference between the aforementioned tab joint and the aforementioned can joint corresponds to the height of the aforementioned rolled edge.

17. The cylindrical secondary battery according to claim 1, characterized in that, The bonding strength between the battery can and the can joint is greater than the bonding strength between the electrode tab and the tab joint.

18. The cylindrical secondary battery according to claim 1, characterized in that, A rolled edge is formed, pressing inward from the periphery of the battery can towards the space between the cover plate and the electrode assembly. The aforementioned tank joint is welded to the flat area of ​​the aforementioned rolled edge.

19. The cylindrical secondary battery according to claim 18, characterized in that, The weld beads formed at the joint of the aforementioned tank are located on the inner side, separated from the boundary of the aforementioned flat area by an interval of more than 0.1 mm.

20. The cylindrical secondary battery according to claim 1, characterized in that, The cover plate is formed with a vent section having a thickness of less than 1 / 10 of the thickness of the cover plate.

21. The cylindrical secondary battery according to claim 1, characterized in that, The height of the main body corresponds to the distance between the current collector plate and the cover plate.

22. The cylindrical secondary battery according to claim 1, characterized in that, The main body does not apply pressure to the aforementioned collector plate.

23. The cylindrical secondary battery according to claim 1, characterized in that, The aforementioned closure covers the edge of the aforementioned cover plate and insulates the aforementioned battery can from the aforementioned cover plate.

24. The cylindrical secondary battery according to claim 1, characterized in that, The distance between the connecting part and the cover plate increases as it moves further away from the main body.

Images