This plate collects the electrode current of the secondary battery and the cylindrical secondary battery uses this plate.

Abstract

The invention relates to a construction of an electrode current collector that does not affect the electrode assembly, even when deformed by folding; and a secondary battery using such construction. The current collector comprises: a main body; a can connector positioned further outward in the axial and radial directions than the main body; and a bridge extending radially and connecting the main body and the can connector. The bridge comprises an inner bend, an inner bridge, a bridge bend, an outer bridge, and an outer bend.

Description

Electrode collector plate of a secondary battery and a cylindrical secondary battery using the same

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0152816, dated November 7, 2023, and Korean Patent Application No. 10-2024-0139347, dated October 14, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to an electrode collector plate of a secondary battery and a cylindrical secondary battery using the same, and relates to an electrode collector plate structure that does not affect an electrode assembly even when deformed by crimping processing, and a secondary battery using the same.

[0003] The process of manufacturing a battery cell using a cylindrical can includes the steps of deep drawing a metal sheet to form a circular bottom portion and a circular tubular side wall connected thereto, accommodating an electrode assembly therein, and then closing the open end of the side wall with a cap.

[0004] A typical method for finishing the open end of the above side wall by covering it with a cap is to form a beaded portion on the side wall, interpose a cap gasket on the axial outer surface of the beaded portion, and form a crimping portion that compresses the edge of the cap.

[0005] Meanwhile, in order to increase the energy density of the can and expand the current path, a structure is being applied in which a portion of the electrode foil is exposed axially at the axial end of the electrode assembly, then bent radially to form an electrode tab, and a current collector plate is employed to electrically connect the electrode tab and the can.

[0006] The current collector plate, which is made of a metal plate in the shape of a plate, has its main body laminated and bonded on the electrode tab of the electrode assembly in the axial direction so as to be electrically connected to the electrode tab, and its radially outer edge is in contact with the can or cap so as to be electrically connected to the can or cap.

[0007] At this time, in the structure of processing the beading portion and the crimping portion and closing the open end of the can with a cap, a structure may be applied in which the edge of the current collector plate is interposed between the axial outer surface of the beading portion and the inwardly bent portion of the crimping portion and pressed so as to make contact with the can or the cap.

[0008] Since the processing of the above crimping section is a process of forming the side wall of the can to press the edge of the cap while interposing the cap gasket, the cap and cap gasket are pressed with a considerably strong external force.

[0009] However, if the external force applied during the crimping process is transmitted to the collector plate, which has relatively weaker rigidity than the side wall, the collector plate may be deformed in an unintended direction, damaging the electrode assembly, or the external force applied during the crimping process may be transmitted directly to the electrode assembly, damaging the electrode assembly.

[0010] The present invention has been devised to solve the above-described problem, and provides a current collector structure having a structure that can induce deformation in a direction that does not cause damage to an electrode assembly even when an external force is applied during a crimping process, and a secondary battery structure using the same.

[0011] In addition, the present invention aims to provide a current collector structure having a structure capable of minimizing the influence of a force applied to process a side wall on an electrode assembly even if deformation of the current collector occurs in an unintended direction, and a secondary battery structure using the same.

[0012] The technical objectives of the present invention are not limited to the purposes mentioned above. Other objectives and advantages of the present invention not mentioned above can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, it will be readily apparent that the objectives and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0013] The present invention, which aims to solve the above-described problem, can be applied to a battery cell including an electrode assembly, a current collector electrically connected to the electrode assembly, and a can that accommodates the electrode assembly and the current collector.

[0014] The can may include a side wall extending axially and an open end provided at one axial end of the side wall.

[0015] The above battery cell may include a cap covering the open end.

[0016] A first end wall is connected to the axial other end of the side wall, and thus the axial other end of the side wall can form a closed end.

[0017] The above electrode assembly may be in the form of a jelly-roll wound around a predetermined axis.

[0018] An electrode tab is provided at one of the axial ends of the electrode assembly corresponding to the open end, and the current collector plate can be electrically connected to the electrode tab.

[0019] The above-mentioned current collector plate can be electrically connected to the can or cap.

[0020] The cap can be fixed to the side wall of the can by being pressed by a beading portion and a crimping portion formed at the open end of the can at the edge thereof.

[0021] A cap gasket may be interposed between the edge of the cap and the side wall.

[0022] The edge of the cap is pressed by the beading portion and the crimping portion while the cap gasket is interposed, thereby sealing the connection portion between the cap and the can.

[0023] The above-mentioned current collector plate includes a main body that is electrically connected to the electrode tab.

[0024] The above main body portion may include an extension portion that is connected to the electrode tab.

[0025] The above main body portion may further include an inner portion connected to the expansion portion on the radially inner side of the expansion portion. The inner portion may also be joined to the electrode tab.

[0026] The connection between the main body and the electrode tab can be achieved by welding, brazing, or soldering. Preferably, the connection can be achieved by laser welding, which irradiates a laser onto the surface of the extension.

[0027] The above-described collector plate includes a can connection portion that is electrically connected to at least one of the side wall and the cap.

[0028] The above can connection portion and the above main body portion can be electrically connected.

[0029] The above can connection part may be positioned radially outside the above main body part.

[0030] The above can connection part may be positioned axially outside the above main body part.

[0031] The above-mentioned collector plate includes a bridge extending radially, the radially inner side of which is connected to the main body portion, the radially outer side of which is connected to the can connection portion.

[0032] The above bridge includes, in order from the radially inner side to the outer side, an inner bend portion, an inner bridge portion, a bridge bend portion, an outer bridge portion, and an outer bend portion.

[0033] The present invention provides a current collector that can be used in the cylindrical secondary battery described above.

[0034] The diameter of the above collector plate may be 35 mm or more and 46 mm or less.

[0035] The above current collector plate includes a main body portion provided to be in contact with and electrically connected to the electrode tab of the electrode assembly.

[0036] The above current collector plate includes a can connection portion that is provided to be electrically connected to at least one of a can that accommodates the electrode assembly and a cap that covers an open end of the can, and is positioned axially and radially outside the main body.

[0037] The above-mentioned collector plate includes a bridge extending radially, the radially inner end of which is connected to the main body portion and the radially outer end of which is connected to the can connection portion.

[0038] The above bridge is connected to the main body through an inner bend portion that is bent axially outward by a first angle from a radially outer end of the main body portion, and includes an inner bridge portion that extends radially outward from the inner bend portion and also extends axially outward.

[0039] The above bridge is connected to the inner bridge portion through a bridge bend portion that is bent radially outward by a second angle from the radially outer end of the inner bridge portion, and includes an outer bridge portion that extends radially outward from the bridge bend portion.

[0040] The above can connection part is connected to the outer bridge part through an outer bend part provided at the radially outer end of the outer bridge part.

[0041] The above can connecting portion may have a shape whose width is wider than the width of the outer bending portion.

[0042] In one example, the first angle of the current collector plate provided before assembling the cylindrical secondary battery may be 60 degrees or more and 75 degrees or less.

[0043] Preferably, the third inclination of the can connection portion of the current collector plate provided before assembling the cylindrical secondary battery toward the axial outer side with respect to the radial outer side may be 20 degrees or more and 30 degrees or less.

[0044] Preferably, by means of the outer bending portion of the current collector plate provided before assembling the cylindrical secondary battery, the can connection portion can be bent radially outward by a third angle from the radially outer end of the outer bridge portion (335).

[0045] Preferably, the third angle may be greater than or equal to 5 degrees and less than or equal to 20 degrees.

[0046] Preferably, the second angle of the current collector plate provided before assembling the cylindrical secondary battery may be 25 degrees or more and 40 degrees or less.

[0047] Preferably, the first extension length of the inner bridge portion may be 0.5 to 2 times the second extension length of the outer bridge portion.

[0048] In another example, the second moment of inertia of the cross-section of the outer bridge portion as viewed in the extension direction of the outer bridge portion may be greater than the second moment of inertia of the cross-section of the inner bridge portion as viewed in the extension direction of the inner bridge portion.

[0049] Preferably, a reinforcing member may be provided on the widthwise edge of the outer bridge portion by bending the widthwise end of the outer bridge portion axially inward.

[0050] Preferably, the main body portion may include an extension portion extending radially outward from a radially outer end of the main body portion.

[0051] The above bridge can be arranged between the extensions in the circumferential direction.

[0052] The above extensions and bridges can each be provided in numbers of four.

[0053] The first width of the connection portion between the above-mentioned extension portion and the above-mentioned main body portion may be 1.5 times or more and 2.5 times or less than the second width of the connection portion between the above-mentioned bridge and the main body portion.

[0054] The present invention provides a cylindrical secondary battery to which the above-described current collector plate is applied.

[0055] The above cylindrical secondary battery includes an electrode assembly having electrode tabs at an axial end, a can accommodating the electrode assembly, a cap covering an open end of the can, and a current collector.

[0056] The can has a beaded portion in which the side wall of the can is radially recessed inward between the electrode assembly and the cap in the axial direction.

[0057] The can connection portion of the above current collector plate is in contact with the axial outer surface of the above beading portion.

[0058] The edge of the cap is pressed by the beading portion and the crimping portion of the side wall while the cap gasket is interposed.

[0059] The above can connection portion is interposed between the cap gasket and the beading portion.

[0060] In a state where the above-mentioned current collector plate is assembled to the above-mentioned cylindrical secondary battery, the can connection portion can be bent axially outward from the radially outer end of the outer bridge portion by the outer bending portion.

[0061] In a state where the above-mentioned collector plate is assembled to the above-mentioned cylindrical secondary battery, the outer bridge portion may have a second slope extending axially inward as it goes radially outward from the bridge bend portion.

[0062] The third angle of the current collector plate provided before assembling the cylindrical secondary battery may be reversed when the current collector plate is assembled to the cylindrical secondary battery.

[0063] The second angle of the current collector plate when assembled to the cylindrical secondary battery may be greater than the second angle of the current collector plate provided before assembling the cylindrical secondary battery.

[0064] The first angle of the current collector plate when assembled to the cylindrical secondary battery may be greater than the first angle of the current collector plate provided before assembling the cylindrical secondary battery.

[0065] According to the present invention, even if an external force is transmitted in the extension direction of the bridge during the crimping and / or sizing process of the can, the first angle and / or the second angle are set so that the bending of the inner bend portion and / or the bridge bend portion can be induced by the external force. Accordingly, the external force applied to the current collector plate by the crimping process certainly acts in a direction that increases the bending angles of the inner bend portion and the bridge bend portion, so that even if deformation of the current collector plate occurs, the electrode assembly is not damaged.

[0066] According to the present invention, even if an external force is transmitted in the extension direction of the bridge during the crimping and / or sizing process of the can, the bending rigidity of the outer bridge portion is secured to be greater than that of other portions, so that bending of the inner bend portion and / or the bridge bend portion can be induced by the external force. Accordingly, the external force applied to the current collector plate by the crimping process certainly acts in the direction of increasing the bending angle of the inner bend portion and the bridge bend portion, so that even if deformation of the current collector plate occurs, the electrode assembly is not damaged.

[0067] According to the present invention, even if an external force is transmitted in the extension direction of the bridge during the crimping and / or sizing process of the can, the bending rigidity of the outer bridge portion is secured to be greater than that of other portions, thereby inducing a reversal of the outer bend portion by the external force. Accordingly, the external force applied to the current collector plate by the crimping process certainly acts in the direction of increasing the bending angles of the inner bend portion and the bridge bend portion, so that even if deformation of the current collector plate occurs, the electrode assembly is not damaged.

[0068] According to the present invention, by reducing the width of the bridge to a level where the internal resistance hardly increases, the buckling resistance of the bridge is lowered to the extent that an external force acting in the extension direction of the bridge cannot transmit the external force to the main body. Accordingly, even if deformation of the bridge and / or can connection occurs during the handling of the current collector plate prior to assembly, and thus deformation of the current collector plate in an unintended direction occurs during the crimping and / or sizing process of the can, the phenomenon of damage to the electrode assembly can be minimized.

[0069] In addition to the effects described above, specific effects of the present invention are described below while explaining specific details for carrying out the invention.

[0070] Figure 1 is an exploded perspective view of the electrode and separator before winding of the electrode assembly accommodated inside the can.

[0071] Fig. 2 is a perspective view of the stacked state of the electrode and separator before winding of the electrode assembly of Fig. 1.

[0072] Figure 3 is a schematic diagram of the process of winding the electrode and separator around the core.

[0073] Fig. 4 is a perspective view of an electrode assembly in the form of a cylindrical jelly-roll assembled by winding it in the laminated form of Fig. 2 as in Fig. 3.

[0074] Fig. 5 is a perspective view showing the electrode tab of the electrode assembly of Fig. 4 folded radially inward.

[0075] Figure 6 is a perspective view showing a state in which a first collector plate is joined to a first electrode tab provided at an axial first end of an electrode assembly facing the first end wall of a can.

[0076] Figure 7 is a perspective view showing a state in which a second collector plate is joined to a second electrode tab provided on an axial second end of an electrode assembly facing the second end wall of the can.

[0077] Figure 8 is a perspective view of a cylindrical battery cell.

[0078] Figure 9 is a front cross-sectional view of the cylindrical battery cell of Figure 15.

[0079] Figure 10 is a plan view and a side view of a comparative example current collector plate applied to a cylindrical battery cell.

[0080] Fig. 11 shows a part of a plan view of the collector plate of Fig. 10.

[0081] Fig. 12 schematically illustrates a portion of the side view of the collector plate of Fig. 10 in an enlarged form.

[0082] Figures 13 to 17 schematically illustrate the process of assembling the collector plate of Figure 12 into a can.

[0083] Figure 18 is a cross-sectional photograph showing damage to the electrode assembly due to abnormal deformation of the collector plate of the comparative example.

[0084] Fig. 19 is a plan view and a side view of a current collector plate of the first embodiment applied to a cylindrical battery cell.

[0085] Figure 20 is a plan view and a side view of a current collector plate of a second embodiment applied to a cylindrical battery cell.

[0086] Figure 21 is an enlarged perspective view of the bridge and can connection of the collector plate of Figure 20.

[0087] Fig. 22 shows a part of a plan view of a current collector plate of the embodiment.

[0088] Figures 23 to 27 schematically illustrate the process of assembling the collector plate of the embodiment into a can.

[0089] [Explanation of symbols]

[0090] 10: Can (housing) 11: Side wall 116: Beading portion 1161: Axial outer surface 117: Crimping portion 1171: Inward bend portion 12: First end wall (second electrode terminal) 14: First electrode terminal 15: Terminal gasket 16: Second end wall 161: Constriction ring portion 162: Cap body 163: Soft portion 17: Lead gasket 19: Insulator 20: Electrode assembly 21: First electrode 22: Second electrode 23: Current collector 24: Active material 25: Support portion 26: Non-conductive portion 27: Electrode tab (notched tab) 28: Separator 29: Core hollow portion 290: Core shaft 31: First current collector plate (positive current collector plate) 311: Terminal connection area 312: Electrode connection area 313: Interconnection area 32: Second collector plate (negative collector plate) 320: Body 321: Inner ring 322: Hole 323: Expansion W1: First width 324: Can connection b3: Third slope 33: Bridge W2: Second width 331: Inner bend a1: First angle 332: Outer bend a3: Third angle 333: Inner bridge b1: First slope L1: First extension length 334: Bridge bend a2: Second angle 335: Outer bridge b2: Second slope L2: Second extension length 336: Reinforcement 39: Welding 70: Battery cell

[0091] The above-described objects, features, and advantages will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily practice the technical idea of ​​the present invention. In describing the present invention, if it is determined that a detailed description of known technologies related to the present invention may unnecessarily obscure the gist of the present invention, a detailed description thereof will be omitted. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

[0092] Although terms like "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless otherwise specified, a "first" component may also be a "second" component.

[0093] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0094] Hereinafter, the phrase "any configuration is placed on (or below)" a component or "on (or below)" a component may mean that any configuration is placed in contact with the upper surface (or lower surface) of said component, and that other configurations may be interposed between said component and any configuration placed on (or below) said component.

[0095] Additionally, when it is described that a component is "connected," "coupled," or "in contact with" another component, it should be understood that the components may be directly connected or in contact with each other, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "in contact with" another component.

[0096] As used herein, singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as "consisting of" or "comprising" should not necessarily be construed to include all of the components or steps described in the specification, and should be construed to mean that some of the components or steps may not be included, or that additional components or steps may be included.

[0097] Throughout the specification, when we refer to "A and / or B", this means A, B, or A and B, unless otherwise stated, and when we refer to "C through D", this means C or more and D or less, unless otherwise stated.

[0098] In describing the embodiment, the axial direction refers to the direction in which the axis forming the winding center of the jelly-roll type electrode assembly extends, the radial direction refers to the direction approaching or moving away from the axis, and the circumferential direction refers to the direction surrounding the axis.

[0099] The battery cell to which the collector plate of the embodiment is applied may be, for example, a cylindrical battery cell having a form factor ratio greater than approximately 0.4. Here, the form factor refers to a value indicating the diameter and height of the cylindrical battery cell. Here, the form factor ratio may be defined as a value obtained by dividing the diameter of the cylindrical battery cell by its height, i.e., the ratio of the diameter (Φ) to the height (H).

[0100] The cylindrical battery cell may be, for example, a 46110 cell, a 48750 cell, a 48110 cell, a 48800 cell, or a 46800 cell. In the numerical value indicating the form factor, the first two numbers indicate the diameter of the cell, the next two numbers indicate the height of the cell, and the last number 0 indicates that the cross-section of the cell is circular.

[0101] The above battery cell may be a cylindrical battery cell having a roughly cylindrical shape, a diameter of approximately 46 mm, a height of approximately 110 mm, and a form factor ratio of 0.418.

[0102] According to another embodiment, a battery cell may be a cylindrical battery cell having a generally cylindrical shape, a diameter of approximately 48 mm, a height of approximately 75 mm, and a form factor ratio of 0.640.

[0103] According to another embodiment, a battery cell may be a cylindrical battery cell having a generally cylindrical shape, a diameter of approximately 48 mm, a height of approximately 110 mm, and a form factor ratio of 0.436.

[0104] According to another embodiment, a battery cell may be a cylindrical battery cell having a generally cylindrical shape, a diameter of approximately 48 mm, a height of approximately 80 mm, and a form factor ratio of 0.600.

[0105] According to another embodiment, a battery cell may be a cylindrical battery cell having a generally cylindrical shape, a diameter of approximately 46 mm, a height of approximately 80 mm, and a form factor ratio of 0.575.

[0106] The present invention can of course also be applied to battery cells having a form factor ratio of approximately 0.4 or less, such as 18650 cells, 21700 cells, etc. For 18650 cells, the diameter is approximately 18 mm, the height is approximately 65 mm, and the form factor ratio is 0.277. For 21700 cells, the diameter is approximately 21 mm, the height is approximately 70 mm, and the form factor ratio is 0.300.

[0107] [Cylindrical battery cell]

[0108] Referring to FIGS. 1 to 9, a cylindrical battery cell (70) includes an electrode assembly (20), a current collector (31, 32) electrically connected to the electrode assembly (20), and a housing (10) that accommodates the electrode assembly (20) and the current collector (31, 32).

[0109] Electrode assembly

[0110] The electrode assembly (20) is prepared by preparing a first electrode (21), a second electrode (22), and a separator (28) extending in the longitudinal direction with a predetermined width as shown in FIG. 1, and stacking the first electrode (21), the separator (28), the second electrode (22), and the separator (28) in that order as shown in FIG. 2, and winding them around a core shaft (290) as shown in FIG. 3, so that it can be manufactured in a cylindrical jelly-roll shape as shown in FIG. 4.

[0111] One of the first electrode (21) and the second electrode (22) may be an anode, and the other may be a cathode. In the embodiment, the first electrode (21) is implemented as an anode, and the second electrode (22) is implemented as a cathode.

[0112] The above first electrode (21) and second electrode (22) are manufactured in the form of sheets extending in the longitudinal direction with a predetermined width. The above electrodes are manufactured in the form of an active material (24) coated on a current collector (23).

[0113] The current collector (23) above may be made of a metal foil. Either the current collector (23) of the first electrode (21) or the current collector (23) of the second electrode (22) may include an aluminum material, and the other may include a copper material. In the embodiment, the current collector (23) of the first electrode (21) is made of an aluminum foil, and the current collector (23) of the second electrode (22) is made of a copper foil.

[0114] The above electrode may include not only a region where the current collector (23) is coated with an active material (24), but also a region where the current collector (23) is not coated with an active material (24). For convenience of explanation, in a two-dimensional region defined by the sheet-shaped current collector (23), a region where the active material (24) is applied and a battery reaction can occur is referred to as a holding region (25) of the electrode, and a region where the active material (24) is not applied and a battery reaction does not occur is referred to as a non-conductive region (26) of the electrode.

[0115] The non-conductive portion (26) of the above electrode may be provided for a function or action other than a battery reaction. For example, the non-conductive portion (26) may provide an electrode tab (27) that electrically connects the electrode to the electrode terminal. Specifically, the current collector (23) of the non-conductive portion (26) itself may be utilized as the electrode tab (27), or a separate tab member may be bonded to the current collector (23) of the non-conductive portion (26) to provide an electrode tab.

[0116] According to the embodiment, the first electrode (21) has a non-woven portion (26) provided at the first end in the width direction, and the second electrode (22) has a non-woven portion (26) provided at the second end in the width direction.

[0117] Referring to FIGS. 2 and 4, the non-conductive portion (26) region protrudes outward in the widthwise or axial direction from the electrode laminate or jelly-roll. The non-conductive portion (26) itself functions as an electrode tab (27). In the widthwise or axial direction, the inner end of the non-conductive portion (26) is positioned further inward than the outer end of the separator (28), and the outer end of the non-conductive portion (26) is positioned further outward than the outer end of the separator (28).

[0118] Referring to FIGS. 1 and 2, a cut line is formed at a predetermined interval in the non-conductive portion (26), thereby providing a plurality of electrode tabs (27) in the shape of flags arranged along the longitudinal direction.

[0119] The embodiment implements the electrode tabs (27) in an equilateral trapezoidal shape. In addition to this, the shape of the electrode tabs (27) may be various shapes such as a semicircle, a semi-ellipse, a triangle, a rectangle, a parallelogram, etc.

[0120] The embodiment is exemplified by a form in which the electrode tabs (27) arranged along the longitudinal direction have the same width (longitudinal dimension). However, the width of the electrode tabs may be gradually or stepwise widened from the core side to the outer circumference side.

[0121] In addition, in the embodiment, a form in which the height (axial dimension) of the electrode tabs (27) gradually increases from the core side to the outer circumference side is exemplified. However, the height of these electrode tabs may be implemented in a form in which they are constant or gradually decrease.

[0122] In addition, in the embodiment, a structure is exemplified in which the electrode tab (27) is deleted in a predetermined section of the centripetal end of the non-conductive portion (26) and a predetermined section of the centrifugal end. However, it is of course possible that the electrode tab may not be deleted in the centripetal end of the non-conductive portion, or that the electrode tab may not be deleted in the centrifugal end of the non-conductive portion, or that neither may be deleted.

[0123] In the jelly roll-shaped electrode assembly (20), the electrode tab (27) can be bent radially and flattened as illustrated in FIG. 5. The electrode tab (27) can be bent radially inward or outward. In the embodiment, a structure in which the electrode tab (27) is bent radially inward is exemplified.

[0124] The electrode tabs (27) above can be bent one by one during the process of forming a jelly roll-shaped electrode assembly (20) by winding the laminate as shown in Fig. 3. Alternatively, the electrode tabs (27) can be bent all at once after the laminate is wound to form a jelly roll-shaped electrode assembly as shown in Fig. 4.

[0125] The electrode tabs (27) of the first electrode (21) and the electrode tabs (27) of the second electrode (22), which are bent and overlapped in the radial direction in this way, can provide a first plane and a second plane that are substantially perpendicular to the axial direction at the axial ends of the electrode assembly (20), respectively.

[0126] <Collective board>

[0127] The electrode tabs (27) exposed at each of the axial ends of the electrode assembly (20) are bent and provided on the substantially flat first and second surfaces, and a first collector plate (31) and a second collector plate (32) can be joined to each other as shown in FIGS. 6 and 7.

[0128] One of the first collector plate (31) and the second collector plate (32) may be a positive collector plate, and the other may be a negative collector plate. In an embodiment, the first collector plate (31) is implemented as a positive collector plate, and the second collector plate (32) is implemented as a negative collector plate.

[0129] The first collector plate (31) and the second collector plate (32) may include copper or aluminum. In an embodiment, the first collector plate (31) includes aluminum and the second collector plate (32) includes copper.

[0130] The above-mentioned collector plate (31, 32) can be manufactured by punching, trimming, piercing, or bending a metal sheet or metal plate.

[0131] Referring to FIG. 6, the first collector plate (31) includes a terminal connection area (311) provided at a portion corresponding to the core hollow portion (29) of the electrode assembly (20), and an electrode connection area (312) provided around the terminal connection area (311). The terminal connection area (311) is arranged at the center of the first collector plate (31) and is provided in a form that covers at least a portion of the core hollow portion (29) of the electrode assembly (20) in the axial direction. The electrode connection area (312) is provided in a form that surrounds the terminal connection area (311) while being spaced apart from the terminal connection area (311) in the radial direction.

[0132] The terminal connection area (311) and the electrode connection area (312) are physically and electrically connected to each other through an interconnection area (313). The interconnection area (313) extends in a radial direction, is connected to the terminal connection area (311) on the radially inner side, and is connected to the electrode connection area (312) on the radially outer side.

[0133] In the embodiment, the interconnection region (313) may extend radially with respect to the terminal connection region (311) and may be arranged in multiple numbers in the circumferential direction. The interconnection region (313) may have a radial extension length longer than the circumferential width.

[0134] The above electrode connection area (312) can be electrically connected by being joined to the first electrode tab (27-1) provided on the first electrode (21) of the electrode assembly (20). The above terminal connection area (311) can be electrically connected by being joined to the first electrode terminal (14) described later.

[0135] Referring to Fig. 7, the second collector plate (32) has a main body (320) including an inner portion (321) having a hole (322) formed in the center. The main body (320) may further include an extension portion (323) extending radially outward from the inner portion (321). A plurality of the extension portions may be spaced apart from each other in the circumferential direction.

[0136] The second collector plate (32) has a can connection part (324) that surrounds the main body part (320) on the radially outer side of the main body part (320). The main body part (320) and the can connection part (324) may be spaced apart from each other in the radial direction.

[0137] The second collector plate (32) above has a bridge (33) connecting the main body (320) and the can connection portion (324). The bridge (33) extends radially and may be spaced apart from each other in a plurality of places along the circumferential direction. The bridge (33) may be arranged between the extension portions (323) in the circumferential direction.

[0138] The above main body (320) can be electrically connected by being joined to the second electrode tab (27-2) provided on the second electrode (22) of the electrode assembly (20). The can connection portion (324) can be electrically connected by being joined to the side wall (11) of the can (10) described later.

[0139] Battery Housing

[0140] The above electrode assembly (20) can be inserted into the housing (10) in a state where the first collector plate (31) and the second collector plate (32) are joined as shown in FIGS. 8 and 9.

[0141] Referring to FIGS. 8 and 9, the housing (10) may include a metal can. The can (10) includes a side wall (11) extending axially between a first end and a second end, and a first end wall (12) connected to the first end of the side wall (11) and extending radially. The first end wall (12) may have a flat disc shape intersecting the axial direction, and the side wall (11) may have a circular tube shape extending along the axial direction.

[0142] The above first end wall (12) and side wall (11) can be manufactured by forming a metal sheet with nickel plated on the surface of steel using a deep drawing process, and trimming the second end of the side wall (11) with a punch while holding it with a blank holder. Of course, the material and manufacturing method of the can (10) are not limited to this.

[0143] In the embodiment, the first end wall (12) and the side wall (11) are connected in a monolithic form. However, the first end wall (12) and the side wall (11) may be manufactured as individual parts and then connected by welding or other methods.

[0144] The first end wall (12) and the side wall (11) of the can (10) partition the internal space of the can from the external space. A terminal hole into which a first electrode terminal (14) can be fitted is provided at the center of the first end wall (12), and the first electrode terminal (14) is installed in a form that penetrates the first end wall (12) through the terminal hole. The first electrode terminal (14) is processed to be plastically deformed with a terminal gasket (15) interposed therebetween and is fixed to the first end wall (12). The terminal gasket (15) is interposed between the first electrode terminal (14) and the first end wall (12), sealing the inside and the outside of the first end wall (12) with the first end wall (12) as the boundary, thereby preventing leakage of the electrolyte and electrically insulating the first electrode terminal (14) and the first end wall (12) from each other.

[0145] However, the method of connecting the first electrode terminal (14) and the can (10) is not limited to this. For example, if the structure can seal between the first electrode terminal (14) and the can (10) and electrically insulate the first electrode terminal (14) and the can (10), various fixing methods other than this plastic processing, such as a bolt-nut joint method or a glass seal method, can also be applied.

[0146] The side wall (11) surrounds the inner space of the can (10) and extends along the axial direction. Accordingly, the inner surface of the side wall (11) radially faces the outer periphery of the electrode assembly (20). The second end of the side wall (11) is open to define the opening of the can (10).

[0147] <Battery cell assembly>

[0148] Referring to Fig. 11, the electrode assembly (20) is accommodated in the can (10) in a state where the first collector plate (31) is aligned toward the first end wall (12) of the can (10). In addition, an insulator (19) is interposed between the first collector plate (31) and the first end wall (12) to electrically insulate the first collector plate (31) and the first end wall (12) from each other.

[0149] The terminal connection area (311) of the first collector plate (31) is electrically connected to and fixed to the first electrode terminal (14). In an embodiment, the first electrode terminal (14) fixed to the can (10) is fixed and electrically connected by being joined to the surface of the terminal connection area (311) of the first collector plate (31) by a heat-fusion method such as welding. The first electrode terminal (14) of the can (10) and the terminal connection area (311) of the first collector plate (31) can be connected after the electrode assembly (20) is placed in the can (10).

[0150] Accordingly, the first electrode terminal (14) can have a first polarity corresponding to the first electrode (21).

[0151] With the electrode assembly (20) accommodated in the can (10), the second collector plate (32) is placed on the opening side. After the electrode assembly (20) is accommodated in the can (10), the area around the second end of the side wall (11) is pressed inward in the radial direction and plastically processed to be concave, thereby forming a beading portion (116). This beading process can be performed so that the beading portion (116) is placed axially between the can connection portion (324) of the second collector plate (32) and the electrode assembly (20).

[0152] The can connection portion (324) of the second collector plate (32) faces and contacts the axial outer surface of the beading portion (116). In order to stably electrically connect the second collector plate (32) and the side wall (11), the can connection portion (324) and the beading portion (116) can be welded.

[0153] Next, an electrolyte is injected into the can (10).

[0154] After the electrolyte is injected, the edge of the second end wall (16) in the form of a lid or cap is placed on the beading portion (116) on which the can connection portion (324) of the second collector plate is placed, thereby covering the opening of the can (10). Specifically, a lead gasket (17) is interposed between the edge of the second end wall (16) and the side wall (11), and the second end of the side wall (11) is caulked radially inward to form a crimping portion (117). The lead gasket (17) is compressed by the beading portion (116) and the crimping portion (117), and accordingly, the radially outer peripheral portion of the second end wall (16) is sealedly fixed to the axial second end portion of the side wall (11).

[0155] The can connection portion (324) of the second collector plate (32) is electrically connected to the can (10) by being joined near the axial second end of the side wall (11). Accordingly, the side wall (11) can have a second polarity corresponding to the second electrode (22).

[0156] The first end wall (12) is electrically connected to the side wall (11). Therefore, the first end wall (12) may also have a second polarity. The diameter of the head of the first electrode terminal (14) arranged on the outside of the first end wall (12) may be approximately 1 / 3 of the diameter of the first end wall (12). In other words, the outer surface of the first end wall (12) may have an area sufficient for the bus bar to be joined.

[0157] According to an embodiment, both a first electrode terminal (14) and a second electrode terminal (12) can be arranged at the axial first end of the battery cell. Accordingly, both a bus bar connected to the first electrode terminal (14) of the battery cell and a bus bar connected to the second electrode terminal (12) can be positioned at the upper portion of the battery cell. In an embodiment, the first electrode terminal (14) is implemented as a positive terminal, and the second electrode terminal (12) is implemented as a negative terminal.

[0158] In addition, the insulator (19) described above electrically insulates the second electrode terminal (12) from the first collector plate (31) so that they do not cause a short circuit.

[0159] [Collective board]

[0160] Referring to FIGS. 10 to 12, the current collector (32) includes a main body (320) that is electrically connected to the electrode tab (27), a can connection part (324) that is electrically connected to the can (10) by being in contact with the radially outer side of the main body (320), and a bridge (33) that connects the can connection part (324) and the main body (320) in the radial direction.

[0161] The above main body (320) includes an extension (323) that is joined to the electrode tab (27), and an inner ring (321) that is connected to the extension (323) on the radially inner side of the extension (323) and has a hole (322) provided in the center.

[0162] The above can connection part (324) is positioned radially and axially outside the main body part (320) through the bridge (33).

[0163] The above bridge (33) includes, in order from the radially inner side to the outer side, an inner bend portion (331), an inner bridge portion (333), a bridge bend portion (334), an outer bridge portion (335), and an outer bend portion (332).

[0164] The inner bridge portion (333) is connected to the main body portion (320) through an inner bend portion (331) that is bent axially outward from the radially outer end of the main body portion (320) by a first angle (a1), and extends radially outward and axially outward from the inner bend portion (331) by a first extension length (L1).

[0165] Accordingly, the inner bridge portion (333) extends in a form inclined axially outward by a first inclination (b1) with respect to the radial outward direction.

[0166] The above outer bridge portion (335) is connected to the inner bridge portion (333) through a bridge bend portion (334) that is bent radially outwardly by a second angle (a2) from the radially outer end of the inner bridge portion (333), and extends radially outward and axially outwardly from the bridge bend portion (334) by a second extension length (L2).

[0167] Accordingly, the outer bridge portion (335) extends in a form inclined axially outward by a second inclination (b2) with respect to the radial outward direction.

[0168] The can connection part (324) is connected to the outer bridge part (335) through an outer bend part (332) provided at a radially outer end of the outer bridge part (335). By the outer bend part (332), the can connection part (324) is bent radially outward from the radially outer end of the outer bridge part (335) by a third angle (a3).

[0169] Accordingly, the can connection portion (324) extends in a form inclined axially outward by a third inclination (b3) with respect to the radial outward direction.

[0170] Referring to Fig. 13, when the main body (320) of the current collector (32) is joined to the electrode tab (27) of the electrode assembly (20), the electrode assembly (20) and the current collector (32) are accommodated in a can (10), and then the side wall (11) is pressed radially inward from the axial outer side of the side wall (11) to form a beading portion (116), an axial outer surface (1161) is formed on the beading portion (116).

[0171] In this state, when the can connection part (324) is pressed in the axial direction to contact the axial outer surface (1161), the inner bending part (331) of the cantilever-shaped bridge (33) is mainly deformed as shown in Fig. 14, and the can connection part (324) comes into contact with the axial outer surface (1161).

[0172] And, as shown in Fig. 15, a welding portion (39) is formed to temporarily secure the can connection portion (324) to the beading portion (116). The welding portion (39) can be simply formed by tab welding.

[0173] And as shown in Fig. 9, when the edge of the can (10) is pressed with the crimping portion (117) while interposing the cap gasket (17), as shown in Fig. 16, the force of the cap (16) and the cap gasket (17) pressed axially inward by the crimping portion (117) acts as a distributed load (f) on the boundary between the bridge (33) and the can connection portion (324) that is spaced apart from the beading portion (116).

[0174] However, as shown in FIGS. 10 and 11, since the circumferential width of the can connection portion (324) is larger than the circumferential width of the outer bridge portion (335), the distributed load (f) intensively deforms the outer bend portion (332) and the outer bridge portion (335) adjacent thereto.

[0175] Then, as shown in Fig. 17, when the outer bridge portion (335) is bent inward in the axial direction, the force (F) is transmitted to the inner bend portion (331) along the extension direction of the bridge (33), thereby pressing the inner bend portion (331) inward in the axial direction.

[0176] Due to the deformation behavior of the current collector (32), as shown in Fig. 18, a deformation occurs in which the radially outer end of the main body (320) digs into the electrode assembly (20) in the axial direction.

[0177] Upon examination, it can be confirmed that this deformation is caused by the distributed load (f) intensively deforming the outer bending portion (332) and the adjacent outer bridge portion (335). In addition, it can be confirmed that this deformation is caused by the fact that the bending angle of the bridge bending portion (334) is not expanded when the external force (F) acts in the extension direction of the bridge (33). In addition, it can be confirmed that this deformation is caused by the fact that the bending angle of the inner bending portion (331) is not expanded when the external force (F) acts in the extension direction of the bridge (33). In addition, it can be confirmed that this abnormal deformation is caused by the fact that the bridge (33) is not sufficiently buckled due to the high rigidity of the bridge (33) when the external force (F) acts in the extension direction of the bridge (33).

[0178] As in the first embodiment illustrated in FIGS. 19 and 22 and the second embodiment illustrated in FIGS. 20 to 22, the embodiments of the present invention have a structure for resolving the cause of the above-described abnormal deformation.

[0179] Referring to FIGS. 19 and 23, the collector plate (32) of the first embodiment is set so that the first angle (a1) of the inner bending portion (331) is 60 degrees or more and 75 degrees or less. Then, even if the bridge (33) is deformed to bring the can connection portion (324) into contact with the beading portion (116), the first inclination (b1) of the inner bending portion (331) can be sufficiently secured as shown in FIG. 24, compared to the comparative example described above.

[0180] Then, even if the external force (F) acts in the extension direction of the bridge (33), the moment arm of the external force (F) transmitted to the inner bending portion (331) through the outer bridge portion (335) is long, so that the external force can be induced to act in a direction that expands the bending angle (a1) of the inner bending portion (331), and at the same time, can be induced to act in a direction that expands the bending angle (a2) of the bridge bending portion (334).

[0181] Meanwhile, if the first angle (a1) is less than 60 degrees, there is a concern that the first slope (b1) may not be sufficiently secured after the bridge (33) is deformed as shown in Fig. 23 to bring the can connection portion (324) into contact with the beading portion (116).

[0182] In addition, if the first angle (a1) is 75 degrees or more, the first extension length (L1) of the inner bridge portion (333) may not be sufficiently secured due to axial space constraints, and thus there is a concern that the moment arm may not be lengthened.

[0183] Referring to FIGS. 19 and 23, the third inclination (b3) of the can connection portion (324) is set to be 20 degrees or more and 35 degrees or less. Then, even if the bridge (33) is deformed to bring the can connection portion (324) into contact with the beading portion (116), the amount of deformation of the bridge (33) can be limited as shown in FIG. 24, thereby sufficiently securing the first inclination (b1) of the inner bend portion (331).

[0184] If the third inclination (b3) is 35 degrees or more, when the bridge (33) is deformed to bring the can connection part (324) into contact with the beading part (116), the amount of deformation of the bridge (33) is excessive, and there is a concern that the first inclination (b1) may not be sufficiently secured after the bridge (33) is deformed.

[0185] Meanwhile, if the third slope (b3) is less than 20 degrees, as shown in FIG. 23, sufficient space cannot be secured in the axial direction between the can connection part (324) and the electrode assembly (20), so there is a risk that the can connection part (324) may interfere with the beading part (116) when machining the beading part (116).

[0186] Referring to FIG. 19 and FIG. 23, the third angle (a3) ​​of the outer bending portion (332) is set to be 5 degrees or more and 20 degrees or less.

[0187] If the third angle (a3) ​​is less than 5 degrees, the bending angle is almost non-existent, so that when the above-mentioned distributed load (f) is applied, the effect of concentrating the bending deformation on the outer bending portion (332) is not exerted, and thus the possibility of the outer bridge portion (335) being bent cannot be ruled out.

[0188] Meanwhile, if the third angle (a3) ​​is 20 degrees or more, as shown in FIG. 23, sufficient space cannot be secured in the axial direction between the can connection part (324) and the electrode assembly (20), and thus, there is a risk that the can connection part (324) may interfere with the beading part (116) when machining the beading part (116).

[0189] Referring to FIGS. 19 and 23, the collector plate (32) of the first embodiment is set so that the second angle (a2) of the bridge bending portion (334) is 25 degrees or more and 40 degrees or less. When the second angle (a2) is 25 degrees or more, even if the external force (F) acts in the extension direction of the bridge (33), the moment arm of the external force (F) transmitted through the outer bridge portion (335) to the inner bending portion (331) is long, so that the external force can be induced to act in a direction that enlarges the bending angle (a1) of the inner bending portion (331), and at the same time, can be induced to act in a direction that enlarges the bending angle (a2) of the bridge bending portion (334).

[0190] Meanwhile, if the second angle (a2) exceeds 40 degrees, sufficient space cannot be secured in the axial direction between the can connection part (324) and the electrode assembly (20), and thus, there is a risk that the can connection part (324) may interfere with the beading part (116) when machining the beading part (116).

[0191] Next, referring to FIGS. 20 and 21, the collector plate (32) of the second embodiment is provided with a reinforcing portion (336) that is bent axially inwardly so that the widthwise end of the outer bridge portion (335) faces the electrode assembly (20) at the widthwise edge of the outer bridge portion (335). That is, the outer bridge portion (335) further includes the reinforcing portion (336) compared to the inner bridge portion (333).

[0192] Accordingly, the second moment of inertia of the cross-section of the outer bridge portion (335) as viewed in the extension direction of the outer bridge portion (335) becomes greater than the second moment of inertia of the cross-section of the inner bridge portion (333) as viewed in the extension direction of the inner bridge portion (333).

[0193] Then, as shown in Fig. 26, the distributed load (f) applied when processing the crimping portion (117) causes deformation concentrated in the outer bending portion (332) and the adjacent can connection portion (324) having relatively low bending rigidity, so that, as shown in Fig. 27, the outer bending portion (332) is lowered further inward in the axial direction, and reverse bending of the outer bending portion (332) is induced.

[0194] Preferably, the can connecting portion (324) has a shape in which its width gradually increases as it extends from the outer bending portion (332), thereby further inducing the above-described deformation.

[0195] Accordingly, since the moment arm of the external force (F) transmitted to the inner bending portion (331) through the outer bridge portion (335) is long, the external force can be induced to act in a direction that expands the bending angle (a1) of the inner bending portion (331), and at the same time, can be induced to act in a direction that expands the bending angle (a2) of the bridge bending portion (334). In particular, since the outer bridge portion (335) has high bending rigidity in the entire extension direction, the load is more concentrated on the bridge bending portion (334), so that more certain bending expansion can be induced.

[0196] In order to secure a moment arm and induce the bending section to bend easily, the first extension length (L1) of the inner bridge section (333) may be set to be 0.5 to 2 times the second extension length (L2) of the outer bridge section (335). In other words, the extension length of the inner bridge section (333) and the extension length of the outer bridge section (335) may be set so that the difference is not more than 2 times.

[0197] Meanwhile, the main body (320) of the above-described collector plate (32) further includes an extension (323) that is arranged between the bridges (33) in the circumferential direction and extends radially outward from the radially outer end of the main body (320).

[0198] According to an embodiment, the first width (W1) of the connection portion between the expansion portion (323) and the main body (320), measured in the circumferential direction, is set to be 1.5 to 2.5 times greater than the second width (W2) of the connection portion between the bridge (33) and the main body (320). In this way, by limiting the width of the connection portion between the bridge (33) and the main body (320) from increasing within the limited circumferential dimension of the current collector (32), the deformation compliance of the inner bending portion (331) can be increased.

[0199] Specifically, the diameter of the collector plate (32) is 35 mm or more and 46 mm or less, and the expansion portion (323) and the bridge (33) can be provided in numbers of four each.

[0200] In the embodiment, the first width (W1) is exemplified as being about 8 mm to 9 mm, and the second width (W2) is exemplified as being about 3.5 mm to 4.5 mm.

[0201] Then, the buckling resistance of the bridge (33) can be lowered, so that even if the collector plate (32) is not deformed in the designed direction due to an unexpected deformation of the collector plate (32) before assembly, the deformation due to the external force can be concentrated on the bending or buckling deformation of the bridge (33), so that the external force is not transmitted to the main body (320).

[0202] Referring to FIGS. 23 to 27, the assembly process of a cylindrical secondary battery using the current collector (32) of the embodiment will be described. As shown in FIG. 23, even if the bridge (33) is deformed to bring the can connection portion (324) into contact with the bead portion (116), the first inclination (b1) can be sufficiently secured as shown in FIG. 24, so that the moment arm of the outer bridge portion (335) with respect to the inner bend portion (331) can be sufficiently secured.

[0203] And as illustrated in Fig. 26, even if a distributed load (f) is applied near the outer bending portion (332) during the crimping portion (117) processing process, the outer bending portion (332) is sufficiently lowered and reversely bent, and bending is induced so that the first angle (a1) and the second angle (a2) become larger. In addition, as illustrated in Fig. 27, the outer bridge portion (335) has a second slope (b2) that extends axially inward as it goes radially outward from the bridge bending portion (334).

[0204] Accordingly, the distributed load (f) does not press the inner bending portion (331) axially inward, and accordingly, deformation of the current collector plate (32) that may occur during the crimping process does not have any effect on the electrode assembly (20).

[0205] It should be understood that the above-described embodiments are illustrative in all respects and not restrictive, and the scope of the present invention will be determined by the claims that follow, rather than by the detailed description set forth above. Furthermore, the meaning and scope of the claims that follow, as well as all possible modifications and variations derived from their equivalent concepts, should be construed as encompassing the scope of the present invention.

[0206] Although the present invention has been described with reference to the drawings exemplified above, it is to be understood that the present invention is not limited to the embodiments and drawings disclosed herein, and that various modifications may be made by those skilled in the art within the scope of the technical idea of ​​the present invention. Furthermore, even if the operational effects according to the configuration of the present invention have not been explicitly described while describing the embodiments of the present invention, it is natural that the effects predictable by the corresponding configuration should also be acknowledged.

Claims

1. A main body (320) provided to be in contact with and electrically connected to the electrode tab (27) of the electrode assembly (20); A can connection portion (324) provided to be electrically connected to at least one of a can (10) that accommodates the electrode assembly (20) and a cap (16) that covers the open end of the can, and is positioned axially and radially outside the main body (320); and A cylindrical secondary battery current collector plate (32) including a bridge (33) extending radially, the radially inner end being connected to the main body (320) and the radially outer end being connected to the can connection part (324); The above bridge (33): An inner bridge portion (333) connected to the main body portion (320) through an inner bend portion (331) bent axially outwardly by a first angle (a1) from the radially outer end of the main body portion (320), and extending radially outwardly from the inner bend portion (331) and also extending axially outwardly; and It includes an outer bridge portion (335) that is connected to the inner bridge portion (333) through a bridge bend portion (334) that is bent radially outwardly by a second angle (a2) from the radially outer end of the inner bridge portion (333), and extends radially outwardly from the bridge bend portion (334); The above can connection part (324) is connected to the outer bridge part (335) through the outer bend part (332) provided at the radially outer end of the outer bridge part (335), The above first angle (a1) is 60 degrees or more and 75 degrees or less, and the current collector plate.

2. In claim 1, the third inclination (b3) of the can connection portion (324) toward the axial outer side with respect to the radial outer side is 20 degrees or more and 35 degrees or less, the current collector plate.

3. In claim 2, by the outer bending portion (332), the can connection portion (324) is bent radially outward at a third angle (a3) ​​at the radially outer end of the outer bridge portion (335), The third angle (a3) ​​above is 5 degrees or more and 20 degrees or less, the current collector plate.

4. A collector plate according to claim 1, wherein the second angle (a2) is 25 degrees or more and 40 degrees or less.

5. In claim 1, the first extension length (L1) of the inner bridge portion (333) is 0.5 to 2 times the second extension length (L2) of the outer bridge portion (335), and the current collector plate.

6. In claim 1, the main body (320) It is arranged between the bridges (33) in the circumferential direction and includes an extension (323) extending radially outward from the radially outer end of the main body (320), A current collector plate in which the first width (W1) of the connection portion between the above-mentioned extension (323) and the above-mentioned main body (320) is 1.5 times or more and 2.5 times or less than the second width (W2) of the connection portion between the above-mentioned bridge (33) and the above-mentioned main body (320).

7. In claim 6, the collector plate is provided with four expansion parts (323) and four bridges (33).

8. In claim 7, the current collector plate (32) has a diameter of 35 mm or more and 46 mm or less.

9. In claim 1, the can connecting portion (324) has a shape in which the width thereof gradually increases as it extends from the outer bend portion (332).

10. A main body (320) provided to be in contact with and electrically connected to the electrode tab (27) of the electrode assembly (20); A can connection portion (324) provided to be electrically connected to at least one of a can (10) that accommodates the electrode assembly (20) and a cap (16) that covers the open end of the can, and is positioned axially and radially outside the main body (320); and A cylindrical secondary battery current collector plate (32) including a bridge (33) extending radially, the radially inner end being connected to the main body (320) and the radially outer end being connected to the can connection part (324); The above bridge (33): An inner bridge portion (333) connected to the main body portion (320) through an inner bend portion (331) bent axially outwardly by a first angle (a1) from the radially outer end of the main body portion (320), and extending radially outwardly from the inner bend portion (331) and also extending axially outwardly; and It includes an outer bridge portion (335) that is connected to the inner bridge portion (333) through a bridge bend portion (334) that is bent radially outwardly by a second angle (a2) from the radially outer end of the inner bridge portion (333), and extends radially outwardly from the bridge bend portion (334); The above can connection part (324) is connected to the outer bridge part (335) through the outer bend part (332) provided at the radially outer end of the outer bridge part (335), A collector plate in which the second moment of cross-section of the outer bridge portion (335) as viewed in the extension direction of the outer bridge portion (335) is greater than the second moment of cross-section of the inner bridge portion (333) as viewed in the extension direction of the inner bridge portion (333).

11. In claim 10, a current collector plate having a reinforcing portion (336) formed by bending the widthwise end of the outer bridge portion (335) axially inwardly on the widthwise edge of the outer bridge portion (335).

12. In claim 1, the main body (320) It is arranged between the bridges (33) in the circumferential direction and includes an extension (323) extending radially outward from the radially outer end of the main body (320), A current collector plate in which the first width (W1) of the connection portion between the above-mentioned extension (323) and the above-mentioned main body (320) is 1.5 times or more and 2.5 times or less than the second width (W2) of the connection portion between the above-mentioned bridge (33) and the above-mentioned main body (320).

13. Electrode assembly (20) having an electrode tab (27) at the axial end; A can (10) that accommodates the above electrode assembly (20); A cap (16) covering the open end of the above can (10); and A cylindrical secondary battery comprising a current collector (32) of any one of claims 1 to 12 electrically connected to the electrode tab (27); The can (10) has a beading portion (116) in which the side wall (11) of the can (10) is radially recessed inward between the electrode assembly (20) and the cap (16) in the axial direction. The can connection part (324) of the above current collector (32) is in contact with the axial outer surface (1161) of the above beading part (116), The edge of the cap (16) is pressed by the beading portion (116) and the crimping portion (117) of the side wall (11) while the cap gasket (17) is interposed therebetween. The above can connecting portion (324) is a cylindrical secondary battery interposed between the cap gasket (17) and the beading portion (116).

14. In claim 13, a cylindrical secondary battery, wherein the can connection portion (324) is bent axially outward from the radially outer end of the outer bridge portion (335) by the outer bend portion (332).

15. In claim 13, the outer bridge portion (335) has a second slope (b2) that extends axially inwardly from the bridge bend portion (334) in the radial direction.

Images