Battery cell, method of manufacturing battery cell, battery pack, and vehicle

Abstract

A battery cell, a method of manufacturing a battery cell, a battery pack, and a vehicle. A cylindrical battery cell includes a battery can in which a roll core type electrode assembly is accommodated, and a cap covering and closing an open end of the battery can. The cap is joined to a tab of an electrode of the electrode assembly. The cap includes two or more electrode connection portions each protruding into an interior of the battery can in an axial direction. The electrode connection portions are spaced apart from each other in a circumferential direction around a center of the cap, and at least two of the electrode connection portions are positioned on opposite sides of the center of the cap. The cap functions as both a current collector plate and a cap, thereby increasing energy density. A manufacturing method, a battery pack including the battery cell, and a vehicle equipped with the battery pack are also disclosed.

Description

[0001] This application is a divisional application of the application with the application number 202310658354.4 (application date: June 5, 2023, and the invention name "Battery cell, method of manufacturing battery cell, battery pack, and vehicle"). TECHNICAL FIELD

[0002] The present invention relates to a cylindrical battery cell and a method of manufacturing the same, a battery pack including the same, and a vehicle including the same. BACKGROUND

[0003] The cylindrical battery cell has a structure in which a jelly-roll type electrode assembly is accommodated inside a cylindrical metal can, which is more robust against impact or high temperature than a pouch-type battery. Accordingly, there is an increasing demand for using can-type cells as battery cells used in a battery pack of a vehicle.

[0004] However, since the can is made of metal, the can-type cell can be heavier than the pouch-type battery. Accordingly, research related to increasing the capacity by increasing the internal volume of each battery can is actively being conducted.

[0005] A process of manufacturing a battery cell using a cylindrical can can include a can preparation operation of deep drawing a metal sheet to form a circular bottom and a circular tubular side wall connected to the circular bottom, and positioning, insulating, and sealing a first electrode terminal in the center of the circular bottom of the can. The process further includes an operation of preparing a jelly-roll type electrode assembly having opposite end portions in an axial direction at which a first current collector plate and a second current collector plate are respectively provided. The process further includes an assembly operation of accommodating the electrode assembly in the can, connecting the first current collector plate to the first electrode terminal, connecting the second current collector plate to the can or a cap, filling the inside of the can with an electrolyte, and closing the open end of the side wall with the cap to complete the manufacturing of the battery cell.

[0006] In the cylindrical battery cell manufactured as described above, since a space for accommodating the second current collector plate should be provided inside the can, the volume of the electrode assembly is inevitably reduced as much as the space, which results in a reduction in energy density. In addition, the conventional process of manufacturing the cylindrical battery cell includes an additional process of manufacturing the second current collector plate and connecting the second current collector plate to the second electrode of the electrode assembly, which increases the manufacturing cost of the battery cell. SUMMARY

[0007] The present invention can advantageously provide a battery cell in which the reliability of electrical connection between the electrodes of the electrode assembly and the electrode terminals of the battery can is still provided despite the omission of the current collector plate for connecting the electrode assembly to the electrode terminals of the battery can.

[0008] The present application can also advantageously provide a battery cell that can reduce manufacturing costs by reducing the number of components and manufacturing man-hours and is simple.

[0009] The present application can also advantageously provide a battery cell having a high energy density and advantageously installed in a vehicle, and a battery pack and a vehicle including the same.

[0010] One aspect of the present application provides a battery cell. Such a battery cell advantageously includes a battery can, an electrode assembly, and a cap. The battery can preferably includes a sidewall extending between a closed end and an opposite open end along an axial direction, wherein the open end defines an opening into an interior of the battery can. The electrode assembly preferably includes two electrodes received within the interior of the battery can such that at least one tab extending from a second electrode of the electrodes is positioned proximate the open end of the battery can. The cap is preferably positioned to close the open end of the battery by covering the opening. The cap preferably includes a plurality of electrode connection portions that project into the interior of the battery can along the axial direction so as to be in direct electrical contact with the at least one tab of the second electrode. Such electrode connection portions are preferably spaced apart from one another in a circumferential direction about a center of the cap, and at least two of the electrode connection portions are preferably positioned on opposite sides of the center of the cap from one another.

[0011] According to at least some aspects of the present application, the electrode connection portions and the tab(s) of the second electrode can be connected by a weld portion.

[0012] According to at least some aspects of the present application, the at least one tab can include a plurality of tabs extending along a radial direction orthogonal to the axial direction such that the tabs at least partially overlap one another along the axial direction.

[0013] According to at least some aspects of the present application, each of the electrode connection portions can be elongated along a radial direction of the cap.

[0014] According to at least some aspects of the present application, there can be four electrode connection portions equally spaced apart in the circumferential direction. According to some such aspects, each of the electrode connection portions can be linearly elongated along a respective radial direction.

[0015] According to at least some aspects of the present application, the electrode connection portions can join one another in a radially central region of the cap by a projection portion of the cap that projects into the interior of the battery can along the axial direction.

[0016] According to at least some aspects of the present application, the electrode connection portions can join one another by a projection portion of the cap that extends circumferentially about a radially outer region of the cap, the projection portion projecting into the interior of the battery can along the axial direction.

[0017] According to at least some aspects of the application, the cap can include electrically conductive material that is in electrical contact with the sidewall of the battery can at the second end of the opening along a radially outer edge of the cap. The electrode connection portions can be integrally formed with the electrically conductive material of the cap. In some examples, each of the electrode connection portions can correspond to a respective recess formed in an outer surface of the cap that faces away from the interior of the battery can along the axial direction.

[0018] According to at least some aspects of the application, the cap can include a liquid inlet in a central portion of the cap. Such a liquid inlet can be positioned on a central protruding region of the cap that can be disposed further away from the interior of the battery can along the axial direction than a respective contact surface of each of the electrode connection portions. Such a contact surface can be a contact surface that is in direct electrical contact with the tab(s) of the second electrode.

[0019] According to some of the above aspects of the application, an intermediate region of the cap can be defined between the circumferentially spaced apart electrode connection portions. Such an intermediate region can be disposed further away from the interior of the battery can along the axial direction than the contact surfaces of the electrode connection portions. In some such aspects of the application, a central protruding region of the cap can be radially spaced apart from the intermediate region by a portion of the outer surface of the cap that is disposed closer to the interior of the battery can along the axial direction than both the central protruding region and the intermediate region. In other such aspects of the application, the central protruding region of the cap can be directly contiguous with the intermediate region in the radial direction.

[0020] According to at least some aspects of the application, the cap can include a vent. Such a vent can be positioned radially outward from the electrode connection portions.

[0021] According to at least some aspects of the application, the first electrode terminal is positioned along the closed end of the battery can. Such an electrode terminal can be electrically insulated from the closed end of the battery can. Additionally, the first electrode of the electrode assembly can be electrically connected with the first electrode terminal via a first current collector plate that is positioned between the electrode assembly and the closed end of the battery can along the axial direction.

[0022] According to at least some aspects of the application, the cap can be constructed and arranged such that an outermost end of the cap that faces away from the interior of the battery can along the axial direction can be spaced further from the interior of the battery can along the axial direction than the open end of the battery can.

[0023] According to at least some aspects of the application, at least two of the electrode connection portions can be positioned on opposite sides of a center of the cap such that a straight line connecting the at least two of the electrode connection portions would extend through the center of the cap.

[0024] According to at least some aspects of the invention, the electrode connection portion can extend radially. Additionally, in some such aspects, the electrode connection portion can extend linearly along a straight line extending through the center of the cap.

[0025] Another aspect of the present invention provides a method for manufacturing the battery cell as described above. This method ideally includes assembling the battery cell, then, after assembling the battery cell, engaging an electrode connection portion to at least one connector of a second electrode, engaging a cap to a battery can, and injecting electrolyte into the battery can. The assembly of the battery cell preferably includes positioning the electrode assembly inside the battery can and positioning the cap to cover an opening at the open end of the battery can, thereby closing the open end of the battery can.

[0026] According to at least some aspects of the invention described above, the electrolyte can be injected into the battery canister via a liquid inlet in the central portion of the cap. Some of these aspects may also include covering the liquid inlet with a stopper.

[0027] According to at least some aspects of the invention described above, at least one connector for joining multiple electrode connection portions to a second electrode can be performed by laser irradiating the outer surface of the cap that is axially away from the interior of the battery can.

[0028] Other aspects of the invention provide a battery pack comprising the battery cells described above, and a vehicle comprising such a battery pack.

[0029] According to some embodiments of the present invention, since the cap is directly electrically connected and fixed to the connector of the second electrode, and the cap is electrically connected and fixed to the side wall of the can, the current collector plate can be omitted. Therefore, the energy density of the battery cell can be increased, the number of components in the battery cell can be reduced, and the manufacturing process can be simplified. Thus, the manufacturing cost of the battery cell can be reduced.

[0030] According to some embodiments of the present invention, since the electrode connection portion of the cap connected to one or more connectors of the second electrode extends in the radial direction, the cap is directly electrically connected from the winding center of the second electrode to its outer periphery, thereby significantly reducing the internal resistance.

[0031] According to some embodiments of the invention, since the cap is provided with a plurality of electrode connection portions extending in the radial direction, and each of the electrode connection portions is recessed downward such that the (one or more) connectors in the axial direction and toward the second electrode protrude into the interior of the battery can, the adhesion between each electrode connection portion and the (one or more) connectors of the second electrode can be ensured by a good quality engagement between them.

[0032] The aforementioned shape is believed to significantly improve the cap's resistance to deformation. Furthermore, it is thought to increase the connection strength between the cap's periphery and the battery can's opening. Therefore, the bonding quality between the battery can and the cap can be significantly improved.

[0033] According to some embodiments of the present invention, since the electrode connection portions of the cap are arranged radially at equal intervals in the circumferential direction, the resistance to deformation can be uniformly ensured in the circumferential direction, and the current path can be uniformly distributed.

[0034] According to some embodiments of the invention, since a pair of electrode connection portions facing each other across the center of the cap are aligned on a line, the shape of the clamp for press-fitting the cap into the battery can or abutting the cap against the electrode assembly can be easily realized, and the trajectory of the welding line can be simplified.

[0035] According to some embodiments of the invention, since the four electrode connectors are arranged at 90-degree intervals, the cap's resistance to deformation can be enhanced, the welding process can be simplified, and the bonding strength between the multiple electrode connection portions and the joints of the second electrode (one or more) can be increased. Furthermore, the location of plastic deformation of the cap is advantageously minimized, thereby reducing any degradation of the cap's rigidity.

[0036] According to some embodiments of the invention, the radially outer sides of the plurality of electrode connection portions may contact the inner circumferential surface of the battery can for press-fit connection, with their guide caps aligned relative to the center of the battery can. Therefore, during the press-fitting of the caps into the battery can, the center of the caps can be naturally aligned with the battery can.

[0037] According to some embodiments of the invention, since the press fit depth of the cap is limited by the electrode connection portion, the electrode connection portion and the (one or more) connectors of the second electrode can be joined in a state that sufficiently ensures adhesion between them.

[0038] According to some embodiments of the invention, the outermost surface of the cap, which is axially positioned above the joint portion that joins the cap and the battery canister, can thus protect such a joint portion.

[0039] Then, when the battery can is correctly placed, i.e., when the outermost surface is placed on the floor, the outermost surface supports the load of the battery cell. In this case, the outermost surface, positioned on both sides of each electrode connection portion in the circumferential direction, has the effect of pressing the electrode connector toward the joint of the second electrode. Therefore, potential damage to the joint between the cap and the (one or more) joints of the second electrode due to vibration or impact can be minimized.

[0040] The liquid inlet can be located in the center of the cap, which can diversify the process of manufacturing the battery cell. In addition, by making the liquid inlet protrude from the electrode connection portion, the transfer of any welding or bonding heat to the electrode assembly can be minimized when the liquid inlet is sealed with a plug.

[0041] When the vent in the cap is located radially outside the electrode connection or welding portion, the area within the cap where the battery's internal pressure acts can be widely secured. Therefore, venting can occur more easily, and when the venting area is disrupted by venting, the electrical connection between the second electrode and the battery can be prevented. Attached Figure Description

[0042] The above and other objects, features, and advantages of the present invention will become more apparent to those skilled in the art from the following detailed description of exemplary embodiments with reference to the accompanying drawings, wherein:

[0043] Figure 1 This is a perspective view showing a cylindrical battery cell according to an embodiment;

[0044] Figure 2 and Figure 3 These are perspective views showing the state before and after the stacking of the first electrode, the second electrode, and the separator for manufacturing the electrode assembly to be housed in the battery can;

[0045] Figure 4 It is shown Figure 3 A planar diagram showing the stacked state;

[0046] Figure 5 and Figure 6 These are respectively showing how to... Figure 3 and Figure 4 A perspective view and a side view of an electrode assembly manufactured by winding a laminate into a core shape;

[0047] Figure 7 and Figure 8 It is a perspective view showing a state in which the current collector plate is engaged to the upper part of the electrode assembly and the current collector plate is not engaged to the lower part of the electrode assembly.

[0048] Figure 9 It shows that Figure 7 and Figure 8 The diagram shows a cross-sectional view of the electrode assembly being housed in the battery can.

[0049] Figure 10 This is a cross-sectional view showing the process of welding the first electrode terminal to the current collector plate;

[0050] Figure 11 This is a cross-sectional view showing the process of placing the cap on the battery can;

[0051] Figure 12 It is a cross-sectional view showing the cap being engaged with the connector of the second electrode of the electrode assembly and the cap being engaged with the edge of the battery can.

[0052] Figures 13 to 15 These are respectively a top perspective view, a bottom perspective view, and a plan view of the cap according to the first embodiment;

[0053] Figure 16 It is along Figure 15 A cross-sectional view taken from line XVI-XVI;

[0054] Figure 17 It is along Figure 15 A cross-sectional view taken from line XVII-XVII;

[0055] Figure 18 This is a cross-sectional view showing the process of assembling a battery can using the cap according to the first embodiment;

[0056] Figures 19 to 21 These are respectively a top perspective view, a bottom perspective view, and a plan view of the cap according to the second embodiment;

[0057] Figure 22 It is along Figure 21 A cross-sectional view taken from line XXII-XXII;

[0058] Figure 23 It is along Figure 21 A cross-sectional view taken from line XXIII-XXIII;

[0059] Figure 24 This is a cross-sectional view showing the process of assembling a battery can using the cap according to the second embodiment;

[0060] Figure 25 and Figure 26 These are a top perspective view and a plan view of the cap according to the third embodiment, respectively;

[0061] Figure 27 It is along Figure 26 A cross-sectional view taken from line XXVII-XXVII;

[0062] Figure 28 and Figure 29 This is a cross-sectional view showing the process of assembling a battery can using the cap according to the third embodiment;

[0063] Figure 30 It is a perspective view showing the state of the connector and cap of the second electrode of the electrode assembly being first engaged before the electrode assembly is housed in the battery can.

[0064] Figure 31 and Figure 32 These are a top perspective view and a plan view of the cap according to the fourth embodiment, respectively;

[0065] Figure 33 It is along Figure 32 A cross-sectional view taken from line XXXIII-XXXIII;

[0066] Figure 34 and Figure 35 This is a cross-sectional view showing the process of assembling a battery can using the cap according to the fourth embodiment;

[0067] Figure 36 This is a top perspective view showing the cap according to the fifth embodiment;

[0068] Figure 37 It is along Figure 36 A cross-sectional view taken from line XXXVII-XXXVII;

[0069] Figure 38 It is along Figure 36 A cross-sectional view taken from line XXXVIII-XXXVIII;

[0070] Figures 39 to 41 This is a flowchart illustrating an embodiment of a method for assembling a battery cell using a cap according to an embodiment of the present invention;

[0071] Figure 42 This is a perspective view showing a battery pack utilizing battery cells according to an embodiment of the present invention; and

[0072] Figure 43 It shows that it is equipped with Figure 42 A picture of a vehicle with a battery pack. Detailed Implementation

[0073] The above-described objects, features, and advantages will now be described in detail with reference to the accompanying drawings. In describing the invention, descriptions of known technologies related to the invention have been omitted where such descriptions might unnecessarily obscure the subject matter. In the drawings, the same reference numerals are used to denote the same or similar parts.

[0074] Although terms such as "first" and "second" can be used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from another, and unless otherwise stated, the first component can be the second component, and vice versa.

[0075] Throughout this specification, unless otherwise stated, each part may be singular or plural. Furthermore, unless the context clearly indicates otherwise, singular expressions used herein include plural expressions.

[0076] In the following text, the arrangement of any component on the “upper part (or lower part)” or “upper (or lower)” of a component means that any component is positioned to contact the upper (or lower) surface of the component. Additionally, this may mean that other components can be inserted between the component and any components positioned on (or below) the component.

[0077] Additionally, when a component is described as “linked,” “connected,” or “attached” to another component, the component can be directly connected or connected to each other, but other components can be “inserted” between the components, or the components can be “linked,” “connected,” or “attached” through other components.

[0078] Throughout the specification, when “A and / or B” is stated, it means A, B or A and B unless otherwise stated; and when the range “C to D” is stated, it means above C and below D unless otherwise stated.

[0079] In the described embodiments, the axial direction refers to the direction in which the axis forming the winding center of the wound electrode assembly extends, the radial direction refers to the direction toward or away from the axis, and the circumferential direction refers to the direction along the periphery of a circle centered on and around the axis.

[0080] The width direction of the electrode assembly before it is wound into a core corresponds to the axial direction of the core. The length direction of the electrode assembly before it is wound into a core corresponds to the circumferential direction of the core.

[0081] In the following text, reference will be made to Figures 1 to 8 The structure of a cylindrical battery cell according to an embodiment of the present invention is described.

[0082] The shape factor of a battery cell refers to the values ​​representing the diameter and height of a cylindrical battery cell. The cylindrical battery cell according to embodiments of the present invention can be, for example, a 46110 cell, a 48750 cell, a 48110 cell, a 48800 cell, or a 46800 cell. In the numerical value representing the shape factor, the first two digits represent the diameter of the cell in mm, the next two digits represent the height of the cell in mm, and the last digit ('0') indicates that the cross-section of the cell is circular.

[0083] According to one embodiment of the present invention, the battery cell may be a cylindrical battery cell having a generally cylindrical shape, a diameter of about 46 mm, a height of about 110 mm, and a form factor ratio of 0.418.

[0084] According to another embodiment, the battery cell can be a cylindrical battery cell having a diameter of about 48 mm, a height of about 75 mm, and a form factor ratio of 0.640.

[0085] According to another embodiment, the battery cell can be a generally cylindrical battery cell having a diameter of about 48 mm, a height of about 110 mm, and a form factor ratio of 0.418.

[0086] According to another embodiment, the battery cell can be a generally cylindrical battery cell having a diameter of about 48 mm, a height of about 80 mm, and a form factor ratio of 0.600.

[0087] According to another embodiment, the battery cell can be a cylindrical battery cell having a generally cylindrical shape, a diameter of about 46 mm, a height of about 80 mm, and a form factor ratio of 0.575.

[0088] Conventionally, battery cells with a shape factor ratio of approximately 0.4 or smaller are already in use. That is, conventionally, cells such as 18650 and 21700 are used. For the 18650 cell, its diameter is approximately 18 mm, its height is approximately 65 mm, and its shape factor ratio is 0.277. For the 21700 cell, its diameter is approximately 21 mm, its height is approximately 70 mm, and its shape factor ratio is 0.300.

[0089] The battery can 10 includes a cylindrical sidewall 11 extending along an axial direction between a closed first end and an open second end, wherein the closed first end is defined by a bottom 12 which is connected along an axial direction to an end of one side of the sidewall 11.

[0090] A hole can be formed in the center of the bottom 12, and the first electrode terminal 13 can be fitted into and connected to the hole. With the terminal washer 14 inserted between the first electrode terminal 13 and the bottom 12, the first electrode terminal 13 can be riveted and fixed to the bottom 12. The terminal washer 14 can be inserted between the first electrode terminal 13 and the bottom 12, and can seal the inside and outside of the battery canister 10 to prevent electrolyte leakage and to electrically insulate the first electrode terminal 13 from the bottom 12.

[0091] However, the connection method between the first electrode terminal 13 and the bottom 12 is not limited to this. For example, various other fixing methods in which the structure forms a seal between the first electrode terminal 13 and the bottom 12 and also electrically insulates the first electrode terminal 13 from the bottom 12 can be used, such as bolt-nut connection method, glass sealing method and maleic anhydride grafted polypropylene (PP-MAH) thermal bonding method.

[0092] The first electrode terminal 13 may have a first polarity, and the battery canister 10 may have a second polarity. Therefore, both the bottom 12 of the battery canister 10 and the sidewall 11 connected to the bottom 12 may have a second polarity. Thus, the bottom 12 surrounding the periphery of the first electrode terminal 13 may constitute a second electrode terminal 15, and the sidewall 11 connected to the bottom 12 may also constitute a second electrode terminal.

[0093] Then, both the first electrode terminal 13 and the second electrode terminal 15 can be disposed at one end of the battery can 10 along the axial direction. Then, in the battery can 10, both the busbar connected to the first electrode terminal 13 and the busbar connected to the second electrode terminal 15 can be positioned along the axial direction at one end of the battery can 10, for example at the top of the battery can 10.

[0094] In one example, the first electrode terminal 13 can be the positive terminal, and the second electrode terminal 15 can be the negative terminal. Of course, the reverse is also possible.

[0095] The electrode assembly 20 is housed inside the battery canister 10. The electrode assembly 20 is manufactured by fabricating a first electrode 21, a second electrode 22, and a separator 28, which extend a predetermined width along the longitudinal direction (e.g., ...). Figure 2 As shown), a laminate is formed by stacking components in the following order: first electrode 21, diaphragm 28, second electrode 22, and diaphragm 28, as shown. Figure 3 and Figure 4 As shown. Then, the laminate is wound around the central axis to form a core configuration.

[0096] The first electrode 21 can be the positive electrode, and the second electrode 22 can be the negative electrode. Of course, the reverse is also possible.

[0097] The first electrode 21 and the second electrode 22 are each manufactured in the form of an electrode sheet. The electrode sheet is manufactured by applying an active material layer 24 to the surface of a metal foil 23. The electrode sheet includes a coated portion 25 coated with the active material layer 24 and an uncoated portion 26 uncoated with the active material layer 24. The positive electrode sheet has an uncoated portion 26 on one side along the width direction, and the negative electrode sheet has an uncoated portion 26 on the opposite side along the width direction.

[0098] In the laminate, the uncoated portion 26 is exposed or protrudes in the width direction. The uncoated portion 26 itself serves as an electrode connector. Although the electrode “connector” used herein may be an integral part of the metal foil 23 protruding outward from the electrode assembly 20, such a “connector” may also be a separately formed conductive component that is firmly and electrically connected to the current collector metal foil 23 of the electrode.

[0099] A flag-shaped notch joint 27 can be formed by forming notches at predetermined intervals in the uncoated portion 26.

[0100] In some embodiments, the notched tabs 27 may each have an isosceles trapezoidal shape. However, the notched tabs 27 may have various shapes such as semicircles, semi-ovals, triangles, rectangles, and parallelograms.

[0101] Additionally, in some embodiments, the notched joints 27 may be arranged along the length direction and have the same width as each other. However, the width of the notched joints 27 may gradually or progressively widen from the winding center to the outer periphery.

[0102] Additionally, in some embodiments, the notch connector 27 may have a height that gradually increases from the winding center to the outer periphery. However, the height of the notch connector 27 may alternatively be constant or gradually decreasing.

[0103] In the electrode assembly 20 in the form of a wound core, the notched connector 27 can be bent radially inward or outward in the radial direction. The structure of the notched connector 27 bent radially inward is as follows: Figure 5 and Figure 6 As shown.

[0104] During the winding of the laminate to form the electrode assembly 20 with a core configuration, the notch joint 27 can be bent individually. Alternatively, after the electrode assembly is wound into a core configuration, the notch joint 27 can be bent all at once.

[0105] In this way, such as Figure 6 As shown, the notch joint 27 of the first electrode 21 and the notch joint 27 of the second electrode 22, which are bent and overlapped in the radial direction, can define a plane that is substantially perpendicular to the axial direction at both ends of the electrode assembly 20 along the axial direction.

[0106] like Figure 7 As shown, the current collector plate 31 can be engaged with a substantially flat surface defined by radially bent notched connectors 27 exposed at both ends of the electrode assembly 20.

[0107] The collector plate 31 can be manufactured by stamping, trimming, piercing and / or bending a sheet of metal.

[0108] Reference Figure 7The current collector plate 31 includes one or more terminal connector portions 32 extending radially from a central portion of the current collector plate 31, an annular portion 33 interconnecting the radially outer ends of the terminal connector portions 32 circumferentially, and one or more electrode connector portions 34 extending radially inward from the annular portion 33 but not connected to the terminal connector portions 32. The central portion of the terminal connector portion 32 covers at least a portion of the hollow portion of the wound center of the electrode assembly 20.

[0109] Before inserting the electrode assembly 20 into the battery canister 10, the electrode connector portion 34 is joined to the notch connector 27 of the first electrode 21 of the electrode assembly 20 by means of laser welding or the like.

[0110] Reference Figure 8 The collector plate may not be connected to the notch connector 27 of the second electrode 22 of the electrode assembly 20.

[0111] like Figure 9 and Figure 10 As shown, with the current collector plate 31 aligned to face the bottom 12 of the battery can 10, the electrode assembly 20 is housed within the battery can 10. In this configuration, an insulator 19 is inserted between the current collector plate 31 (the first current collector plate) and the bottom 12 of the battery can 10 to electrically insulate the current collector plate 31 from the bottom 12.

[0112] Alternatively, the terminal connector portion 32 of the current collector plate 31 is joined to the first electrode terminal 13 by resistance welding, ultrasonic welding, or laser welding. The welding apparatus 100 for welding the current collector plate 31 to the first electrode terminal 13 performs the welding by axially approaching the inner surface of the center of the terminal connector portion 32 of the current collector plate 31 through the hollow portion of the winding center of the electrode assembly 20. Alternatively, the current collector plate 31 and the first electrode terminal 13 can be joined by copper soldering or tin soldering.

[0113] Reference Figure 11 and Figure 12 The notch connector 27 of the second electrode 22 can be directly connected to the cap 40 covering the opening defined by the open end of the battery can 10. The second electrode 22 is electrically connected to the cap 40 via a welded portion W between the cap 40 and the notch connector 27. Alternatively, the notch connector 27 and the cap 40 can be joined by brazing or soldering.

[0114] The cap 40 is formed of a conductive material. Alternatively, the cap 40 can be integrally formed of this material. The edge of the cap 40 is joined and electrically connected to the sidewall 11 of the battery can 10 and is fixedly sealed. Therefore, the second electrode 22 can be electrically connected to the cap 40 and the battery can 10. Various methods capable of achieving electrical connection and sealing, such as welding, brazing, and soldering, can be applied to the joining of the cap 40 and the battery can 10.

[0115] Figure 11 and Figure 12 The example of the cap 40 and its assembly process shown is exemplary. Various embodiments of the structure and assembly method of the cap 40 will be described below. Although the joining parts described below are joined by welding, the invention is not limited thereto.

[0116] [First Implementation Method]

[0117] In the following text, refer to Figures 13 to 18 The first embodiment of the cap and the structure of the battery cell in which the cap is used will be described.

[0118] The cap 40 may be made of a circular metal sheet. The cap 40 includes one or more electrode connection portions 41 recessed in a direction corresponding to the axial direction of the battery cell 72. The electrode connection portions 41 may be formed by stamping, i.e., by pressing the metal sheet using a press and one or more forming dies. Therefore, due to this stamping, each protrusion defined by the electrode connection portions 41 on the lower side of the cap 40 corresponds to a corresponding recess in the upper side of the cap.

[0119] The bottom of the electrode connection portion 41 is in close contact with and engaged with the corresponding contact surface of the notch connector 27 of the second electrode 22 of the electrode assembly 20. The thickness of the electrode connection portion 41, manufactured by pressing a metal sheet, is slightly less than the thickness of the metal sheet. Therefore, when the surface of the electrode connection portion 41 is irradiated by the laser L, the localized heat generated by the laser can melt and bond the surfaces of the electrode connection portion 41 and the notch connector 27 that are in contact with the bottom contact surface of the electrode connection portion 41.

[0120] The electrode connection portion 41 is configured with multiple protrusions that project downwards along the axial direction into the interior of the battery can 10. Figures 13 to 18 In the illustrated embodiment, four electrode connection portions 41 are formed radially by linearly elongating along their respective radial directions. These electrode connection portions 41 are preferably equidistantly spaced in the circumferential direction around the center 46 of the cap 40. In the case of four such electrode connection portions 41, the spacing can be 90 degrees. Furthermore, the electrode connection portions 41 can join together in the radially central region of the cap 40, such that the central region of the cap 40 also defines a protrusion projecting downwards into the interior of the battery can 10 in the axial direction. Such a central protrusion can be formed at the same depth as the electrode connection portions 41 and continuous with each of them. Therefore, in the case of four equidistantly spaced electrode connection portions 41, such electrode connection portions and the central protrusion joining them together define a cross-shaped shape, such as... Figures 13 to 15 As shown.

[0121] The weld portion W of the notch joint 27 for joining one or more of the electrode connection portions 41 to the second electrode 22 of the electrode assembly 20 can have a linear shape formed along the radial direction corresponding to the extension direction of the corresponding electrode connection portion 41. According to this embodiment, a weld portion W with a linear, radially oriented extension shape can be formed for each of the plurality of electrode connection portions 41.

[0122] The cap 40 provides an outermost surface 44, which is the surface of the battery can 10 that will contact the floor when the battery can 10 is placed upright, such that the cap 40 of the battery can 10 faces the floor. Each outermost surface 44 is located at a position higher than the electrode connection portion 41 (i.e., away from the interior of the battery can 10 in the axial direction) and is located between two adjacent electrode connection portions 41 in the circumferential direction.

[0123] Therefore, with the outermost surface 44 pressed axially by a clamp to ensure tight contact between the electrode connection portion 41 and the notch connector 27, the electrode connection portion 41 and the notch connector 27 can be welded together by irradiating the surface of the electrode connection portion 41 with a laser. Then, due to the pressure of the clamp, the electrode connection portion 41 is pressed against the notch connector 27 on the opposite side of the weld line, thus welding can be reliably performed.

[0124] A pair of electrode connection portions 41 on the opposite side of the center 46 of the cap 40 have a shape in which the pair of electrode connection portions 41 are arranged along a straight line passing through the center 46 of the cap 40. Therefore, when forming a weld line, the weld line for the two electrode connection portions 41 aligned along the line can be formed by a single movement of the laser welding machine. When the first electrode connection portion, the second electrode connection portion, the third electrode connection portion, and the fourth electrode connection portion are arranged sequentially along the circumferential direction of the cap 40 of the first embodiment, the first electrode connection portion and the third electrode connection portion can be welded at once, and the second electrode connection portion and the fourth electrode connection portion can be welded at once.

[0125] Furthermore, according to this embodiment, when the outermost surface 44 between the first and third electrode connection portions is pressed using a clamp, the cap 40 can still behave as a rigid body without twisting or bending due to the large second moment of inertia formed by the concave shapes of the second and fourth electrode connection portions, despite the pressure of the clamp. In fact, it is believed that by positioning at least two electrode connection portions 41 on opposite sides of the center 46 of the cap 40, the strength and stiffness of the cap 40 can be increased particularly effectively without increasing material and weight. In this regard, without being limited to a specific operational theory, it is considered that arranging such electrode connection portions 41 along a straight line extending through the center 46 of the cap, especially when such electrode connection portions extend along this line (and even extend from the central region to the opposite side of the cap 40), will define a portion of the cap structure similar to a reinforcing beam extending across the cap. Additionally, the cap is further reinforced by four electrode connection portions 41 equidistant from the center 46, extending along two straight lines orthogonal to each other, similar to a vertical beam with a torque-resistant connection between them.

[0126] As described above, in this embodiment, four electrode connection portions 41 are formed, such that all four electrode connection portions 41 can be welded via two laser scanning paths.

[0127] When the number of electrode connection portions 41 is excessive, the strength of the cap 40 may be weakened. Furthermore, when only two or three electrode connection portions 41 are formed, it is difficult to generate a cross-section that provides sufficient second-order rotational inertia in the circumferential direction.

[0128] In this embodiment, when the four electrode connection portions 41 are formed in a cross or "+" shape within the cap 40, the welding process can be performed accurately and conveniently. This provides the cap 40 with increased resistance to torsion and bending, and also reduces or prevents weakening of the cap 40's strength due to the pressing process. Furthermore, the cap 40 can not only function as a current collector plate, but also maintain the strength to retain its original function of sealing the opening of the battery canister 10.

[0129] The outer radial periphery of the cap 40 has a shape configured to engage with the axial end of the sidewall 11 at the open end of the battery can 10. For this purpose, the electrode connection portion 41 can be formed to be radially spaced inward from the outer periphery of the cap, such that the lower surface of the cap 40 defines a base surface 47 along the outer radial periphery having a circular profile extending around the center 46 of the cap 40. Figure 18As shown, the abutment surface 47 of the cap 40 can contact the axial end surface along the edge of the sidewall 11 at the open end of the battery can 10, and these contact surfaces can be welded together by a laser guided radially inward along the outer periphery of the battery can 10 to form a joint portion M.

[0130] The radially outer side of the electrode connection portion 41 may define a press-fitting outer wall 45 having an outer diameter corresponding to the inner diameter of the battery can 10. Therefore, when the cap 40 is assembled to the battery can 10, the press-fitting outer walls 45 of the plurality of electrode connection portions 41 each contact the inner peripheral surface of the battery can 10 and are press-fitted while sliding against the inner peripheral surface of the battery can 10, so as to guide the alignment of the cap 40 relative to the battery can 10.

[0131] According to the first embodiment, four press-fit outer walls 45 are evenly distributed in the circumferential direction and contact the battery can 10 over the entire periphery of the inner circumferential surface. Therefore, the cap 40 can be press-fitted into the battery can 10 relatively easily.

[0132] As described above, the cap 40 of this embodiment has the advantage of easy assembly because when the electrode connection portion 41 is pressed, the press-fit outer wall 45 is pressed together.

[0133] Furthermore, according to the structure of the cap 40 in this embodiment, since the laser used to weld the cap 40 to the battery can 10 is directed in the radial direction, if it is found that the base surface 47 of the cap 40 is not in close contact with the axial end surface of the sidewall 11 in one or more areas, the laser will not be directed to damage the electrode assembly 20 located inside the battery can 10.

[0134] According to the first embodiment, since even when Figure 18 When the battery canister 10 is inverted and upright, the outermost surface 44 of the cap 40 is positioned further outward along the axial direction than the joint portion M. Therefore, the joint portion M does not directly contact the floor, making the joint portion M more easily protected.

[0135] When the cap 40 described above is used, it is not necessary to use a current collector plate to electrically connect the connector of the second electrode 22 to the battery canister 10. Therefore, the number of components and assembly time can be reduced, and a larger internal volume can be generated, thereby increasing the energy density. Since the cap 40, which is electrically connected to the battery canister 10, is directly connected to the metal foil 23 of the second electrode of the electrode assembly 20 via a welded portion W extending in the radial direction, the current path is preferably uniformly distributed, so that the internal resistance can also be significantly reduced.

[0136] [Second Implementation]

[0137] In the following text, refer to Figures 19 to 24 This section will describe a second embodiment of the cap and the structure of a battery cell using the cap. In describing the second embodiment, content repeated with the first embodiment described above will be omitted. Therefore, content not described in one embodiment will be understood from other embodiments. Furthermore, it will be readily understood that components of one embodiment may replace or be added to components of other embodiments, or may be omitted.

[0138] The cap of the second embodiment differs from that of the cap of the first embodiment in that the protruding portion in the form of an annular protrusion 48 extends along the radially outer peripheral region of the cap 40, and the annular protrusion 48 protrudes downward in the axial direction into the interior of the battery can 10. The annular protrusion 48 connects to each electrode connection portion 41. The radially outer periphery of the cap 40 is defined by the radially outer periphery of the annular protrusion 48, and the outer periphery of the annular protrusion 48 is configured to be positioned within the inner diameter of the side wall 11 of the battery can 10. Therefore, the radially outer periphery constitutes a press-fit outer wall 45.

[0139] The annular protrusion 48 can be formed simultaneously with the formation of one or more electrode connection portions 41. The outermost surface 44 of the cap 40 may be located on the intermediate region 49 of the cap 40 defined between the circumferentially spaced electrode connection portions 41, radially inside the annular protrusion 48, and the cap 40 may have a shape in which the bottom of the annular protrusion 48 is connected to the bottom of the electrode connection portion 41. That is, the outermost surface 44 is located on the intermediate region 49 of the cap 40, which is circumferentially positioned between the electrode connection portions 41 and radially positioned inside the annular protrusion 48.

[0140] Unlike the first embodiment, such as Figure 24 As shown, in the cap 40 of the second embodiment, the outer periphery of the press-fit outer wall 45 can contact the inner peripheral surface of the battery can 10 and can be press-fitted into the battery can 10. The press-fit outer wall 45 does not limit the press-fit depth of the cap 40 in the axial direction. In the second embodiment, the press-fit depth of the cap 40 can be limited by the electrode connection portion 41. That is, the cap 40 can be press-fitted to a position where the bottom of the electrode connection portion 41 is in close contact with the notch connector 27 of the electrode assembly 20.

[0141] In the above state, the electrode connection portion 41 and the notch connector 27 are welded along the length direction of the electrode connection portion, that is, welded in the radial direction to form a welded portion W, and the upper end of the outer peripheral surface of the press-fit outer wall 45 and the upper end of the side wall 11 of the battery can 10 are welded to form a joint portion M.

[0142] The outermost surface 44 is axially located above the axial end 39 of the press-fit outer wall 45. That is, the height of the outermost surface 44 is higher than the height of the press-fit outer wall 45. Therefore, with the joint portion M formed on the press-fit outer wall 45 and the side wall 11, even when the battery can 10 is erected to allow the cap 40 to contact the floor, the joint portion M will not directly receive the load from the floor, thus protecting the joint portion M.

[0143] In addition, since the outermost surface 44 contacts the floor to receive the load, and the load is applied in the axial direction along which the electrode connection portion 41 and the joint of the second electrode 22 are pressed together, the weld portion W between the cap 40 and the notch joint 27 is also protected.

[0144] Because the cross-section of the cap 40 in the second embodiment has a high second-order moment of inertia in the circumferential direction of the edge, it has strong resistance to deformation and bending.

[0145] [Third Implementation Method]

[0146] In the following text, refer to Figures 25 to 30 The third embodiment of the cap and the structure of the battery cell in which the cap is used will be described.

[0147] Compared to the first embodiment, the cap 40 of the third embodiment further includes a liquid inlet 42 disposed at the center portion of the cap 40. The liquid inlet 42 can be aligned with the hollow portion of the winding center of the electrode assembly 20.

[0148] The liquid inlet 42 may be located on the central protruding area of ​​the cap 40 (such as a circular protrusion 43 that protrudes slightly upward from the electrode connection portion 41 of the cap 40). The height of the protrusion 43 is set to be lower than the height of the outermost surface 44. When the liquid inlet 42 is covered and closed by the stopper 50 (which will be described below), the height of the stopper 50 may also be lower than the height of the outermost surface 44.

[0149] Because the protrusion 43 protrudes upwards above the bottom of the cap 40, the heat used for joining is preferably not transferred to the electrode assembly 20 when the electrolyte is injected through the liquid inlet 42 and then the liquid inlet 42 is covered by the plug 50 and joined by welding, thereby reducing the risk of damaging the diaphragm.

[0150] The cap 40 of the first and second embodiments described above is not provided with a separate liquid inlet. Therefore, when the cap 40 is positioned on the battery can 10 during the manufacturing of those earlier embodiments, the electrolyte injection process can be performed first before covering the battery can 10 with the cap 40, since there is no separate liquid inlet in the battery can 10.

[0151] However, when the liquid inlet 42 is provided in the cap 40, as in the third embodiment, electrolyte can be injected through the liquid inlet 42 even after the cap 40 is assembled onto the battery can 10 and the welded portion W and the joint portion M are formed. Then, compared to joining the cap 40 to the battery can 10 with electrolyte already injected, the third embodiment with the liquid inlet 42 may advantageously result in a reduction of any thermal effects on the electrolyte caused by the joining. Furthermore, even when the stopper 50 is joined to the periphery of the liquid inlet 42, the likelihood of the joining heat applied to the stopper 50 affecting the electrolyte should be reduced because the protrusion 43 protrudes upwards away from the interior of the battery can.

[0152] Since the plug 50 is also positioned below the outermost surface 44, the plug 50 does not directly receive the load even when the battery cell is upright with the cap 40 in contact with the floor.

[0153] On the other hand, the liquid inlet 42 formed in the central portion of the cap 40 can be a channel through which a device for welding the first electrode terminal 13 to the first electrode 21 can enter and exit. Therefore, as... Figure 30 As shown, the cap 40 can be attached to the battery can 10 with the connector already connected to the second electrode 22 of the electrode assembly 20. That is, as... Figure 30 As shown, the electrode assembly 20 can be housed in the battery canister 10 with the current collector plate 31 engaged with the connector of the first electrode 21 of the electrode assembly 20 and the cap 40 engaged with the connector of the second electrode 22. Furthermore, the process of welding the current collector plate 31 to the first electrode terminal 13 can be performed through the liquid inlet 42 of the cap 40 and the hollow portion of the winding center of the electrode assembly 20.

[0154] [Fourth Implementation Method]

[0155] In the following text, refer to Figures 31 to 35 The fourth embodiment of the cap and the structure of the battery cell in which the cap is used will be described.

[0156] Similar to the relationship between the third and first embodiments, compared to the second embodiment, the fourth embodiment also includes a liquid inlet 42 in the central portion of the cap 40. Furthermore, compared to the second embodiment, the cap of the fourth embodiment has a shape in which the radially inner side of the central region 49 of the cap 40 is radially spaced outward from the protrusion 43 by the annular portion 55 of the cap 40. Therefore, both the radially inner and outer sides of the central region 49 can have an arcuate shape.

[0157] A vent 60, in the form of a weak or thin portion, is positioned along the bottom of the annular protrusion 48 of the cap 40. The vent 60 can be formed by forming a notch in either or both of the upper and lower surfaces of the annular protrusion 48. The vent 60 is positioned radially outward of each of the electrode connection portions 41, where the vent 60 can extend circumferentially around the electrode connection portion 41.

[0158] The vent 60 preferably has sufficient strength to prevent deformation under any applied force when the cap 40 is press-fitted into the battery can 10. On the other hand, when the internal pressure increases rapidly due to a short circuit in the battery can 10, the vent 60 becomes disconnected to separate the electrode connection portion 41 of the cap 40 from its press-fit outer wall 45. Therefore, the electrical connection between the battery can 10 and the electrode connection portion 41 of the connector to the second electrode 22 is broken, and the internal space of the battery can 10 is opened outward to expel the gas causing the internal pressure.

[0159] Furthermore, the vent 60 is located radially outside the central region 49 of the cap 40, and the outermost surface 44 is positioned on this central region 49. Additionally, as described above, the outermost surface 44 is located on the central region 49 of the cap 40, situated circumferentially between the electrode connection portions 41.

[0160] Therefore, when the internal pressure of the battery can 10 increases, the internal pressure is applied to the underside of the cap 40, forcibly moving the portion of the cap 40 located radially inward of the vent 60 upward. This force acts strongly in four locations in the circumferential direction (i.e., on the underside of the intermediate region 49 between the electrode connection portions 41 circumferentially on the cap 40). Thus, the internal pressure of the battery can 10 can be smoothly transmitted to the vent 60 to cause a smooth rupture of the vent 60.

[0161] In the fourth embodiment, the vent 60 is provided radially inside the press-fit outer wall 45 of the cap 40 and radially outside the electrode connection portion 41 and the intermediate region 49 located between the electrode connection portion 41. However, the vent 60 formed in the cap 40 is not limited to this. For example, the vent can be provided in the plug 50 covering the liquid inlet 42, can be formed in the joint between the liquid inlet 42 and the plug 50, or can be formed by the joint M between the cap 40 and the battery canister 10. That is, according to this embodiment, by implementing the vent structure in the cap 40 or in the joint between the cap 40 and other components, it is possible to avoid providing a separate volume for the vent structure. Therefore, the energy density of the battery cell can be further improved.

[0162] [Fifth Implementation]

[0163] In the following text, refer toFigures 36 to 38 The fifth embodiment of the cap will be described.

[0164] The fifth embodiment of the cap differs from the fourth embodiment in that the protrusion 43 providing the liquid inlet 42 is directly adjacent to or directly connected to the radially inner side of the intermediate region 49 circumferentially positioned between the electrode connection portions 41.

[0165] Reference Figure 32 In the fourth embodiment of the cap, the protrusion 43 is surrounded by an annular portion 55 of the cap 40, which radially separates the protrusion 43 from the central region 49. On the other hand, as... Figure 37 As shown, in the cap 40 of the fifth embodiment, the protrusion 43 is directly connected to the central region 49 of the cap 40. Due to the above structure, when heat is generated during the welding of the stopper 50 to seal the liquid inlet 42, the heat conduction path is limited to directly transferring heat to the central region 49, and substantially not to the electrode assembly 20. Therefore, any negative impact of the bonding heat on the electrode assembly 20 can be advantageously reduced.

[0166] Additionally, it should be noted that in all the above embodiments, such as Figure 38 As shown, since both sides of each electrode connection portion 41 are adjacent to the intermediate region 49 in the circumferential direction, the heat generated when the electrode connection portion 41 is welded to the notch joint 27 of the second electrode 22 is dissipated through the outermost surface 44 of the intermediate region 49. Therefore, any negative impact of bonding heat on the electrode assembly 20 can be advantageously reduced.

[0167] [Methods for manufacturing battery cells]

[0168] Since each of the caps 40 in the above embodiments has the natural function of a cap and also serves as a current collector plate for the second electrode, the method of manufacturing the battery cell is different from the conventional method of manufacturing a battery cell, which involves a conventional current collector plate for the second electrode.

[0169] In addition, in embodiments of the invention where the cap 40 includes a liquid inlet 42, the liquid inlet 42 can be used as a channel for the process of connecting the current collector plate 31 to the first electrode terminal 13, which can provide greater flexibility in the method of manufacturing the battery cell.

[0170] First, combine Figure 39 The flowchart describes the manufacturing method. This manufacturing method can be used when the cap 40 does not include the liquid inlet 42.

[0171] The manufacturing method includes preparing a battery canister 10 to which a first electrode terminal 13 is fixed, and preparing an electrode assembly having a first electrode and a second electrode. The first electrode and a current collector can be connected and engaged to one end of the electrode assembly in the axial direction.

[0172] Next, when the current collector faces the bottom 12 of the battery can 10, the electrode assembly 20 is inserted into the battery can 10, and the current collector plate 31 of the electrode assembly 20 is joined to the first electrode terminal 13 (by welding or the like) which is fixed to the bottom 12 of the battery can 10.

[0173] Then, the electrolyte is injected into the battery can 10 through the open end of the battery can 10.

[0174] Subsequently, the opening end of the battery can 10 is sealed by covering it with a cap 40. In this case, engagement is performed while the electrode connection portion 41 of the cap 40 is in close contact with one or more connectors of the second electrode 22 of the electrode assembly 20. Then, the periphery of the opening end of the battery can 10 is engaged to the periphery of the cap 40.

[0175] According to the manufacturing method described above, there is no need for a separate current collector plate bonding process for the second electrode 22.

[0176] Next, we will combine Figure 40 The flowchart describes another manufacturing method. This manufacturing method can be used when the cap 40 includes a liquid inlet 42.

[0177] The manufacturing method includes preparing a battery canister 10 to which a first electrode terminal 13 is fixed, and preparing an electrode assembly having a first electrode and a second electrode. The first electrode and a current collector can be connected and engaged to one end of the electrode assembly in the axial direction.

[0178] Next, with the current collector facing the bottom 12 of the battery can 10, the electrode assembly 20 is inserted into the battery can 10, and the current collector plate 31 of the electrode assembly 20 is joined to the first electrode terminal 13 (by welding or similar means), which is fixed to the bottom 12 of the battery can 10.

[0179] Subsequently, the opening end of the battery can 10 is sealed by covering it with a cap 40. In this case, engagement is performed while the electrode connection portion 41 of the cap 40 is in close contact with one or more connectors of the second electrode 22 of the electrode assembly 20. Then, the periphery of the opening end of the battery can 10 is engaged to the periphery of the cap 40.

[0180] Then, the electrolyte is injected into the battery tank 10 through the liquid inlet, after which the liquid inlet is closed and sealed with a plug 50.

[0181] According to the manufacturing method described above, a separate bonding process for the current collector plate used for the second electrode 22 is not required. Furthermore, the bonding between the cap 40 and the second electrode 22, as well as the bonding between the cap 40 and the battery canister 10, can be performed before the interior of the battery canister 10 is filled with electrolyte. Therefore, the heat generated during bonding can be prevented from affecting the electrolyte.

[0182] Next, we will combine Figure 41 The flowchart describes another manufacturing method. This manufacturing method can be applied to situations where the cap 40 is provided with a liquid inlet 42.

[0183] The manufacturing method includes preparing a battery can 10 to which a first electrode terminal 13 is fixed, and preparing an electrode assembly having a first electrode and a second electrode. The first electrode and a current collector can be connected and engaged to one end of the electrode assembly in the axial direction. Additionally, the electrode connection portion 41 of the cap 40 and one or more connectors of the second electrode can be connected and engaged to the other axial end of the electrode assembly. That is, the cap can be first engaged to the second electrode of the electrode assembly before the electrode assembly is housed in the battery can.

[0184] Next, with the current collector facing the bottom 12 of the battery can 10, the electrode assembly 20 is inserted into the battery can 10. During this process, the cap 40 moves to a position covering the open end of the battery can 10.

[0185] Next, the current collector plate 31 of the electrode assembly 20 is joined (by welding or the like) to the first electrode terminal 13, which is fixed to the bottom 12 of the battery can 10. Then, the periphery of the open end of the battery can 10 is joined to the periphery of the cap 40.

[0186] Then, the electrolyte is injected into the battery tank 10 through the liquid inlet 42, and then the liquid inlet is closed and sealed with the stopper 50.

[0187] According to the manufacturing method described above, a separate bonding process for the current collector plate used for the second electrode 22 is not required. Furthermore, the bonding between the cap 40 and the second electrode 22, as well as the bonding between the cap 40 and the battery canister 10, can be performed before the interior of the battery canister 10 is filled with electrolyte. Therefore, bonding heat can be prevented from affecting the electrolyte. Additionally, the cap 40 is first integrated into the electrode assembly 20, eliminating the need for separate management of the cap 40, thereby further simplifying the assembly process.

[0188] [Battery packs and vehicles]

[0189] Reference Figure 42The battery cell 72 with the aforementioned cap and / or the battery cell 72 manufactured using the aforementioned method can be housed in the casing 71 of the battery pack 70. The battery pack 70 can be formed using battery modules, each battery module being an intermediate form of the assembly, or, as shown in the accompanying drawings, the battery pack 70 can be formed directly without battery modules.

[0190] Because the battery cell 72 itself has a relatively large volume, manufacturing the battery pack 70 without using intermediate structures such as battery modules is not particularly difficult. Furthermore, since the second electrode of the battery cell 72 is connected via a cap, the internal resistance is low and the energy density is high. Therefore, the resulting battery pack 70 is expected to have an even higher energy density.

[0191] A battery pack 70 with increased energy density can store the same amount of energy while having a reduced size and weight. Therefore, as... Figure 43 As shown, when the battery pack 70 using battery unit 72 is installed in a vehicle such as a vehicle 80 that uses electricity as an energy source, the energy of the vehicle can be further increased, thereby increasing the vehicle's range.

[0192] It should be understood that the described embodiments are illustrative in all respects and not restrictive, and the scope of the invention will be indicated by the appended claims rather than the detailed description described. Furthermore, the meaning and scope of the appended claims, as well as all variations and modifications derived from equivalent concepts, should be interpreted as being included within the scope of the invention.

[0193] Although the invention has been described with reference to exemplary accompanying drawings, it should be understood that the invention is not limited to the embodiments and drawings disclosed in this specification, and those skilled in the art will understand that various modifications are possible without departing from the scope and concept of the invention. Furthermore, although not all operational effects of the configuration according to the invention are explicitly described in the description of embodiments of the invention, it should be understood that predictable effects from this configuration are also acceptable.

Claims

1. A battery cell, the battery cell comprising: A battery canister including a sidewall extending in an axial direction between a first end and a second end, the second end defining an opening into the interior of the battery canister; An electrode assembly including a first electrode and a second electrode, the electrode assembly being housed inside the battery can such that at least one connector extending from the second electrode is positioned close to the second end of the battery can. as well as A cap, positioned to close the second end of the battery can by covering an opening at the second end. The cap includes a plurality of electrode connection portions that protrude into the interior of the battery can along the axial direction and are spaced apart from each other so as to make direct electrical contact with at least one connector of the second electrode.

2. The battery cell according to claim 1, wherein, The plurality of electrode connection portions and the at least one connector of the second electrode are connected by a welding portion.

3. The battery cell according to claim 1, wherein, The at least one connector includes a plurality of connectors extending along a radial direction orthogonal to the axial direction, such that the plurality of connectors at least partially overlap each other along the axial direction.

4. The battery cell according to claim 1, wherein, Each of the plurality of electrode connection portions extends radially along the cap.

5. The battery cell according to claim 1, wherein, The plurality of electrode connection portions include four electrode connection portions that are equidistantly spaced in the circumferential direction.

6. The battery cell according to claim 5, wherein, Each of the plurality of electrode connection portions extends linearly along its respective radial direction.

7. The battery cell according to claim 1, wherein, The plurality of electrode connection portions are joined together in the radial central region of the cap by a protruding portion of the cap, the protruding portion of the cap protruding into the interior of the battery can along the axial direction.

8. The battery cell according to claim 1, wherein, The plurality of electrode connection portions are joined together by protruding portions of the cap, the protruding portions of the cap extending circumferentially around the radially outer region of the cap, and the protruding portions of the cap protruding into the interior of the battery can along the axial direction.

9. The battery cell according to claim 1, wherein, The cap includes a conductive material, and wherein the conductive material is in electrical contact with the sidewall of the battery can at the second end along the radial outer edge of the cap.

10. The battery cell according to claim 9, wherein, The plurality of electrode connection portions are integrally formed using the conductive material of the cap.

11. The battery cell according to claim 10, wherein, Each of the plurality of electrode connection portions corresponds to a corresponding recess formed in the outer surface of the cap, which is opposite to the interior of the battery can along the axial direction.

12. The battery cell according to claim 1, wherein, The cap includes a liquid inlet in the central portion of the cap.

13. The battery cell according to claim 12, wherein, The liquid inlet is located on the central protruding area of ​​the cap, which is configured to be further away from the interior of the battery can along the axial direction than the corresponding contact surface of each of the plurality of electrode connection portions, the contact surface being in direct electrical contact with the at least one connector of the second electrode.

14. The battery cell according to claim 13, wherein, The middle region of the cap is defined between circumferentially spaced electrode connection portions, the middle region of the cap is configured to be further away from the interior of the battery can than the contact surface of the electrode connection portions along the axial direction, and wherein the central protruding region of the cap is radially spaced from the middle region to a portion of the outer surface of the cap that is configured to be closer to the interior of the battery can than the central protruding region and the middle region along the axial direction.

15. The battery cell according to claim 13, wherein, The central region of the cap is defined between circumferentially spaced electrode connection portions, the central region of the cap is configured to be further away from the interior of the battery can than the contact surface of the electrode connection portions along the axial direction, and wherein a central protruding region of the cap is directly adjacent to the central region in the radial direction.

16. The battery cell according to claim 1, wherein: The cap includes an exhaust port, and The exhaust port is positioned radially outward from the plurality of electrode connection portions.

17. The battery cell according to claim 1, wherein: The first electrode terminal is positioned along the first end of the battery can, and the first electrode terminal is electrically insulated from the first end of the battery can. The first electrode of the electrode assembly is electrically connected to the first electrode terminal via a first current collector plate, which is positioned in the axial direction between the electrode assembly and the first end of the battery can.

18. The battery cell according to claim 1, wherein, The cap is constructed and arranged such that the outermost end of the cap, which is further away from the interior of the battery can along the axial direction, is spaced further away from the interior of the battery can than the second end of the battery can.

19. The battery cell according to claim 1, wherein, At least two of the plurality of electrode connection portions are positioned on opposite sides of the center of the cap, such that a straight line connecting the at least two of the plurality of electrode connection portions extends through the center of the cap.

20. The battery cell according to claim 1, wherein, At least two of the plurality of electrode connection portions extend in the radial direction.

21. The battery cell according to claim 20, wherein, At least two of the plurality of electrode connection portions extend linearly along a straight line extending through the center of the cap.

22. A method for manufacturing a battery cell, the method comprising the following steps: The battery cell according to claim 1 is assembled by positioning the electrode assembly inside the battery can and positioning the cap to cover the opening at the second end of the battery can, thereby closing the second end of the battery can; after assembling the battery cell, the plurality of electrode connection portions are joined to the at least one connector of the second electrode; The cap is attached to the battery canister; as well as Electrolyte is injected into the battery canister.

23. The method according to claim 22, wherein, The electrolyte is injected into the battery canister via a liquid inlet in the central portion of the cap.

24. The method according to claim 23, further comprising the following step: Cover the liquid inlet with a stopper.

25. The method according to claim 22, wherein, The step of joining the plurality of electrode connection portions to the at least one connector of the second electrode is performed by laser irradiating the outer surface of the cap that is away from the interior of the battery can along the axial direction.

26. A battery pack comprising the battery cell according to claim 1.

27. A vehicle comprising the battery pack according to claim 26.

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