Battery cell

Abstract

Provided is a battery cell in which an end portion of a current collector of each electrode of an electrode assembly is welded to a component functioning as a current collector plate. The battery cell comprises: a jelly-roll-type electrode assembly in which a first electrode and a second electrode are wound around an axis with a separator interposed therebetween; an electrode terminal which has welded thereto an axial end portion of a first current collector of the first electrode protruding to an axial first end portion of the electrode assembly and extending axially outward; and a lid which has welded thereto an axial end portion of a second current collector of the second electrode protruding to an axial second end portion of the electrode assembly and extending axially outward.

Description

battery cell

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0192954 filed on December 20, 2024, and all contents disclosed in the document of said Korean patent application are incorporated herein as part of this specification.

[0002] The present invention relates to a battery cell, and more specifically, to a battery cell in which the end of a current collector of each electrode of an electrode assembly is welded to a component that functions as a current collector plate.

[0003] With the proliferation of electric vehicles, the capacity of cylindrical battery cells manufactured using cylindrical battery cans as housings is increasing. Conventional cylindrical battery cells required a separate tab member to connect the electrodes of the electrode assembly to the electrode terminals of the housing.

[0004] As battery cell capacity increased, conventional cylindrical battery cell structures utilizing separate tabs inevitably suffered from high internal resistance. Consequently, battery cells are being developed that reduce internal resistance by expanding the current path through a tabless structure, which directly utilizes the current collector of the electrode assembly as a tab. However, even this tabless structure involves bonding a metal foil-type current collector to a separate collector plate, which is then bonded to an electrode terminal or can; thus, the collector plate merely serves as a substitute for the tab's function and does not represent a form where the tab is completely eliminated.

[0005] If a part functioning as a tap exists in this way, the current must ultimately pass through it, so the disadvantage of the current path becoming detoured or lengthened still persists. Furthermore, the occurrence of defects increases, such as localized overheating or breakage in the part functioning as the tap. Moreover, when such defects occur, it causes a problem of increased internal resistance.

[0006] The present invention was devised to solve the aforementioned problems and aims to provide a battery cell that shortens the current path and lowers internal resistance by directly connecting the electrodes and terminals of the battery cell without a tap structure.

[0007] The present invention aims to provide a battery cell that eliminates defects or current path bypassing problems that may occur due to the presence of a tab by removing the tab function portion connecting the electrode and terminal of the battery cell.

[0008] The present invention aims to provide a battery cell capable of increasing energy density by omitting a tab structure.

[0009] The present invention aims to provide a battery cell equipped with a vent function and a CID (current interrupt device) function while omitting a tap structure.

[0010] The present invention aims to provide a battery cell in which both a first electrode terminal and a second electrode terminal are disposed on the upper side and can be vented upward.

[0011] The present invention aims to provide a battery cell capable of bottom cooling.

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

[0013] The present invention can be applied to a battery cell comprising an electrode assembly and a housing that accommodates the electrode assembly.

[0014] The above electrode assembly may be in the form of a jelly-roll in which a first electrode and a second electrode are wound around a core axis with a separator interposed therebetween.

[0015] To solve the above-mentioned problem, the present invention welds an electrode terminal to the axial end of a first current collector of a first electrode that protrudes from the axial first end of the electrode assembly and extends axially outward, and welds a lid to the axial end of a second current collector of a second electrode that protrudes from the axial second end of the electrode assembly and extends axially outward.

[0016] Accordingly, the electrode terminal functions as a first current collector plate, and the lead can function as a second current collector plate.

[0017] The above housing may comprise a side wall extending axially and surrounding the perimeter of the electrode assembly, a first end wall connected to a first axial end of the side wall and extending radially, having a terminal hole through which the electrode terminal passes, and a second end wall connected to a second axial end of the side wall and extending radially.

[0018] Preferably, the lead can form the second end wall.

[0019] In contrast, the lead and the second end wall may be composed of separate parts.

[0020] The above electrode assembly may be cylindrical.

[0021] The above housing may include a metal can.

[0022] The above housing may be cylindrical.

[0023] The above electrode terminal may have a current collecting plate portion that extends in a radial direction and is welded to the first current collector.

[0024] The above current collector plate may be in the form of a plate. Preferably, the above current collector plate may be in the form of a disc.

[0025] An insulator may be interposed between the electrode terminal and the first end wall in the axial direction. Specifically, the insulator may be interposed between the current collector plate and the first end wall.

[0026] The above electrode terminal may further comprise a neck portion extending axially outward from the above current collection plate portion.

[0027] The above neck portion can penetrate the terminal hole of the first end wall.

[0028] The above neck portion can be connected to the central portion of the above current collection plate portion.

[0029] The above neck portion can be integral with the above current collection plate portion.

[0030] The above neck portion can be connected to the above current collection plate portion in a monolithic form.

[0031] The above neck portion may be in the shape of a cylinder.

[0032] The neck portion can be substantially concentrically aligned with the core hollow portion of the electrode assembly in the axial direction.

[0033] The electrode terminal may further comprise a head portion that is connected to the neck portion and extends further outward in a radial direction than the neck portion.

[0034] The above head portion may be positioned on the outer side of the first end wall.

[0035] The head portion can be manufactured as a separate part from the neck portion and then combined with the neck portion.

[0036] In contrast, the head portion is connected to the neck portion in a monolithic form, and the neck portion may be plastically processed radially outward after penetrating the terminal hole and extend radially outward.

[0037] The battery cell may further include an injection port for injecting electrolyte into the housing.

[0038] Preferably, the injection port may be provided at the electrode terminal.

[0039] The above-mentioned injection port may be provided in the neck portion. Specifically, the injection port may be provided in a form that penetrates the neck portion in the axial direction. Preferably, the injection port may be provided in the central portion of the neck portion.

[0040] The above electrode terminal may further be provided with a stopper portion that blocks the injection port.

[0041] The above plug portion may be provided in the above head portion, which is manufactured as a separate part from the above neck portion.

[0042] In contrast, the above plug portion may be manufactured as a separate part from the above head portion.

[0043] The above head portion can provide a terminal surface to which a bus bar is joined.

[0044] Additionally or optionally, the terminal surface may be provided on the surface of the neck portion.

[0045] Additionally or optionally, the terminal surface may be provided in the plug portion.

[0046] The above electrode terminal is electrically insulated from the first end wall and can be sealed and installed in the terminal hole.

[0047] A gasket may be compressed and interposed between the electrode terminal and the first end wall.

[0048] The side wall and the first end wall of the above housing can be connected in a monolithic form.

[0049] The edge of the second end wall and the axial second end of the side wall can be seam welded.

[0050] The present invention further provides a method for manufacturing the battery cell described above.

[0051] The above manufacturing method may include the step of aligning the first axial end of the first current collector so that it extends further axially outward than the separator and the second axial end of the second current collector so that it extends further axially outward than the separator, and winding the first electrode, the second electrode, and the separator to produce an electrode assembly.

[0052] The above manufacturing method may further include the step of welding the axial end of the first current collector to the electrode terminal by applying axial pressure with the electrode terminal held in a heating jig press while the electrode terminal is heated to a temperature above the melting point of the first current collector.

[0053] Additionally, while welding the axial end of the first current collector to the electrode terminal, the electrode assembly can be cooled by gripping the circumferential surface of the electrode assembly near the axial end with a cooling jig holder.

[0054] The above manufacturing method may further include the step of welding the axial end of the second current collector to the lead by pressing the lead, which is held in a heating jig press, in the axial direction while the lead is heated to a temperature above the melting point of the second current collector.

[0055] Additionally, while welding the axial end of the second current collector to the lead, the electrode assembly can be cooled by gripping the circumferential surface of the electrode assembly near the axial end with a cooling jig holder.

[0056] The above manufacturing method may further include the step of axially inserting an electrode assembly, in which the electrode terminal and the lead are welded, into the housing in the axial direction so that the electrode terminal faces the terminal hole.

[0057] The electrode terminal may protrude further axially outward than the first end wall by penetrating the terminal hole of the first end wall when the process of inserting the electrode assembly into the housing is completed.

[0058] The above manufacturing method may further include the step of seam welding the edge of the second end wall and the axial second end of the side wall while the electrode assembly is inserted into the housing.

[0059] In one example, the second end wall may be formed by the lead. Accordingly, the second end wall may be formed by welding the lead to the side wall.

[0060] In another example, the second end wall may be composed of a separate component from the lead. Accordingly, the second end wall can be welded in close contact with the side wall while the lead is embedded.

[0061] Preferably, such welding can be performed by scanning with a laser.

[0062] Additionally, while welding the second end wall to the side wall, the periphery of the axial second end of the side wall can be gripped with a cooling jig holder to cool the housing and the electrode assembly.

[0063] The above manufacturing method may further include the step of injecting an electrolyte into the housing after seam welding the second end wall and the side wall.

[0064] The above electrolyte can be introduced into the hollow core of the electrode assembly through the above injection port.

[0065] The above manufacturing method may further include the step of injecting an electrolyte into the housing and then sealing the injection port of the electrolyte.

[0066] Preferably, the plug portion may be provided in the head portion, which is manufactured as a separate part from the neck portion. Accordingly, when sealing the injection port, the electrode terminal can be sealed and fixed to the first end wall by compressing the gasket interposed between the electrode terminal and the first end wall. Specifically, the plug portion is forcibly pressed into and fixed to the injection port, and in this process, the head portion can compress the gasket onto the outer surface of the first end wall.

[0067] A vent notch may be provided in the first end wall. The vent notch may extend perimeterly to surround the terminal hole from the radial outer side of the terminal hole.

[0068] The battery cell of the present invention can directly connect the electrodes and terminals of the battery cell without a tap structure by directly welding the end of the current collector to an electrode terminal or a component of a can. Accordingly, the current path can be shortened and internal resistance can be lowered.

[0069] The present invention allows the tap function portion to be completely eliminated from the battery cell by directly welding the end of the current collector to the electrode terminal or the component of the can. Therefore, there are absolutely no defect problems or current path bypass problems that may occur due to the presence of the tap function portion.

[0070] The present invention reduces waste of internal housing space caused by the tab structure by directly welding the end of the current collector to an electrode terminal or a component of a can. Accordingly, the volume of the electrode assembly can be further secured, thereby increasing the energy density of the battery cell.

[0071] The battery cell of the present invention can have a vent function and a CID (current interrupt device) function while increasing energy density.

[0072] The battery cell of the present invention allows for venting upward while arranging both the first electrode terminal and the second electrode terminal on the upper part of the housing, thereby facilitating cooling of the lower part.

[0073] In addition to the effects described above, the specific effects of the present invention are described together with the specific details for implementing the invention below.

[0074] Figure 1 is a perspective view of the stacked state of the electrode and the separator before winding the electrode assembly.

[0075] Figure 2 is a side view of the stacked structure of Figure 1 viewed in the longitudinal direction.

[0076] Figure 3 is a schematic diagram of the process of winding the electrode and the separator around the core.

[0077] Figure 4 is a perspective view of an electrode assembly in the form of a cylindrical jelly-roll assembled by winding it as in Figure 3 in the stacked form of Figure 2.

[0078] FIG. 5 is a perspective view showing the state in which an electrode terminal is joined to a first current collector exposed at the axial first end of an electrode assembly facing the first end wall of a can.

[0079] FIG. 6 is a perspective view showing a state in which a lid is bonded to a second current collector exposed at the axial second end of an electrode assembly facing the second end wall of a can.

[0080] FIG. 7 is a side cross-sectional view showing the process of welding the ends of the first current collector and the second current collector of the electrode assembly to the electrode terminals and leads of FIG. 5 and 6.

[0081] Figure 8 is a side cross-sectional view showing the completed state of the welding process illustrated in Figure 7.

[0082] FIG. 9 is a side cross-sectional perspective view of a cylindrical housing of a battery cell according to the present invention.

[0083] FIG. 10 is a side cross-sectional view showing the process of inserting an electrode assembly into a can such that the electrode terminal faces the first end wall and the lead becomes the second end wall.

[0084] FIG. 11 is a side cross-sectional view showing the process of forming a second end wall by welding a lead to the side wall of the can after completing the insertion process of FIG. 10, and injecting an electrolyte through the injection port of the electrode terminal penetrating the first end wall.

[0085] FIG. 12 is a side cross-sectional view showing the state in which the injection port is sealed and the electrode terminal is sealed and fixed to the first end wall after welding and injection of FIG. 11.

[0086] [Explanation of the symbol]

[0087] 10: Can (Housing) 11: Side wall 12: First end wall 13: Terminal hole 14: Vent notch 16: Second end wall (Lid) 19: Insulator 20: Electrode assembly 21: First electrode 22: Second electrode 23: Current collector 23-1: First current collector 23-2: Second current collector 24: Active material 25: Retaining part 26: Non-retaining part 27: Electrode tab 27-1: First electrode tab 27-2: Second electrode tab 28: Separator 29: Winding core hollow part 290: Winding core shaft 30: Electrode terminal 31: Current collector plate part 32: Neck part 33: Liquid injection port 34: Stopper part 35: Head part 36: Terminal surface 40: Gasket 70: Cooling jig holder 80: Heating jig press

[0088] The aforementioned objectives, features, and advantages are described in detail below with reference to the attached drawings, thereby enabling those skilled in the art to easily implement the technical concept of the present invention. In describing the present invention, detailed descriptions of known technologies related to the present invention are omitted if it is determined that such descriptions would unnecessarily obscure the essence of the invention. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the attached drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

[0089] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless specifically stated otherwise, the first component may also be the second component.

[0090] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0091] In the following, the statement that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0092] In addition, where it is stated that one component is "connected," "combined," or "contacted" with another component, it should be understood that while the components may be directly connected or contacted with each other, another component may be "interposed" between each component, or each component may be "connected," "combined," or "contacted" through another component.

[0093] Singular expressions used in this specification include plural expressions unless the context clearly indicates otherwise. In this application, terms such as "composed of" or "comprising" should not be interpreted as necessarily including all of the various components or steps described in the specification, and should be interpreted as meaning that some of the components or steps may be omitted or additional components or steps may be included.

[0094] Throughout the specification, "A and / or B" means A, B, or A and B unless specifically stated otherwise, and "C to D" means C or more and D or less unless specifically stated otherwise.

[0095] In describing the embodiments, the term "axial direction" refers to the direction in which the axis forming the winding center of the jelly-roll type electrode assembly extends, the term "radial direction" refers to the direction approaching or moving away from the said axis, and the term "circumferential direction" refers to the direction surrounding the said axis. The width and length directions of the electrode and separator before winding correspond to the axial and circumferential directions of the jelly-roll after winding. The upper and lower surfaces of the electrode and separator before winding correspond to the radial inner and outer surfaces of the electrode and separator of the jelly-roll after winding.

[0096] In describing the embodiments below, repetitive descriptions common to different embodiments may be omitted. That is, it is obvious that an example of one embodiment and an example of another embodiment can be combined, substituted, or omitted to implement another embodiment.

[0097] [Battery Cell]

[0098] The battery cell of the embodiment may have a structure in which an electrode assembly (20) is embedded in a housing (10).

[0099] The above battery cell may be cylindrical.

[0100] The above housing (10) may be a hollow metal can (10).

[0101] The electrode assembly (20) can be manufactured into a cylindrical jelly-roll shape as shown in FIG. 4 by preparing a first electrode (21), a second electrode (22), and a separator (28) that are extended in the longitudinal direction with a predetermined width, as shown in FIG. 1 and FIG. 2, and stacking them in the order of the first electrode (21), the separator (28), the second electrode (22), and the separator (28), and winding them around a core shaft (290) as shown in FIG. 3.

[0102] One of the first electrode (21) and the second electrode (22) may be an anode and the other may be a cathode. An embodiment implements the first electrode (21) as an anode and the second electrode (22) as a cathode.

[0103] The first electrode (21) and the second electrode (22) are manufactured in the form of a sheet extending in the longitudinal direction with a predetermined width. The electrodes are manufactured in the form in which an active material (24) is coated on a current collector (23).

[0104] The above current collector (23) may be made of metal foil. Either one of the first current collector (23-1) of the first electrode (21) and the second current collector (23-2) of the second electrode (22) may be made of aluminum and the other may be made of copper. An embodiment implements the first current collector (23-1) as aluminum foil and the second current collector (23-2) as copper foil.

[0105] The above electrode may include not only an area where the active material (24) is coated on the current collector (23), but also an area where the active material (24) is not coated on the current collector (23). For convenience of explanation, in a two-dimensional area defined by the sheet-shaped current collector (23), the area where the active material (24) is applied and capable of causing a battery reaction is referred to as the electrode retaining portion (25), and the area where the active material (24) is not applied and thus does not cause a battery reaction is referred to as the electrode uncoated portion (26). According to this explanation, the area where the active material (24) is not applied on both sides of the sheet-shaped current collector (23) may be the electrode uncoated portion (26) since it is an area where a battery reaction does not occur. On the other hand, even if the active material is coated on only one side of the current collector (23) in the electrode, if at least a portion of the said coated area is in contact with another electrode and a separator (28) in between, since this is an area where a battery reaction can occur in a two-dimensional area defined by the sheet-shaped electrode, the area where the active material (24) is coated on at least one side of the current collector (23) may be the electrode holding portion (25).

[0106] The non-electric portion (26) of the above electrode may be provided for a function or operation other than a battery reaction. For example, the non-electric portion (26) may provide an electrode tab (27) that electrically connects the electrode to an electrode terminal. Specifically, the current collector (23) of the non-electric portion (26) itself may be utilized as the electrode tab (27).

[0107] According to the embodiment, the first electrode (21) is provided with a non-removable portion (26) at the first end in the width direction, and the second electrode (22) is provided with a non-removable portion (26) at the second end in the width direction.

[0108] Referring to FIGS. 1, 2 and 4, the unoccupied portion (26) region protrudes outward in the widthwise or axial direction from the electrode laminate or jelly-roll. The unoccupied portion (26) itself functions as an electrode tab (27). In the widthwise or axial direction, the inner end of the unoccupied portion (26) is positioned further inward than the outer end of the separator (28), and the outer end of the unoccupied portion (26) is positioned further outward than the outer end of the separator (28).

[0109] The embodiment is implemented in a structure in which the above-mentioned non-removable portion (26) is extended and arranged along the entire longitudinal direction of the electrodes (21, 22). In addition, the axial protrusion distance of the above-mentioned non-removable portion (26) is implemented in a constant shape along the longitudinal direction of the electrodes (21, 22).

[0110] However, alternatively, the unwound portion (26) may be provided only in a portion of the lengthwise direction of the electrodes (21, 22). For instance, the unwound portion (26) may be omitted in a portion of the lengthwise core-side end and may be omitted in a portion of the lengthwise outer-side end.

[0111] Additionally, the above-mentioned non-removable portion (26) may be implemented in a form that is continuously extended along the longitudinal direction of the electrode, or may be implemented in a form that is discretely arranged and extended along the longitudinal direction of the electrode. However, extending it in a form that is as continuous as possible may be advantageous for increasing the buckling resistance of the above-mentioned non-removable portion (26) against axial pressure.

[0112] Additionally, the above-mentioned unwound portion (26) may be extended with a changing axial height along the longitudinal direction of the electrode. For example, the axial height of the above-mentioned unwound portion (26) may increase or decrease continuously or stepwise as it moves from the core side to the outer periphery side. Considering that buckling resistance increases as the winding radius of the unwound portion decreases, it may be preferable for the above-mentioned unwound portion to decrease as it moves from the core side to the outer periphery side.

[0113] The axial ends of the electrode tabs (27) exposed at each axial end of the electrode assembly (20) can be welded to the electrode terminal (30) and the lid (16), respectively, as shown in FIGS. 5 to 8.

[0114] The unoccupied portion (26), defined by the area where the first current collector (23-1) is exposed to the first axial end of the electrode assembly (20), can function as the first electrode tab (27-1). Likewise, the unoccupied portion (26), defined by the area where the second current collector (23-2) is exposed to the second axial end of the electrode assembly (20), can function as the second electrode tab (27-2).

[0115] The electrode terminal (30) may be made of a metal material having a higher melting point than the first current collector (23-1). And the lead (16) may be made of a metal material having a higher melting point than the second current collector (23-2).

[0116] The electrode terminal (30) has a current collecting plate portion (31) that extends radially to be welded to the first current collector (23-1). The current collecting plate portion (31) may be in the shape of a disc.

[0117] The electrode terminal (30) further comprises a neck portion (32) extending axially outward from the current collector plate portion (31). The neck portion (32) may be in the shape of a cylinder that is positioned in the center of the current collector plate portion (31) and is integrally connected with the current collector plate portion (31).

[0118] Referring to FIG. 7, the electrode terminal (30) can be held in a heating jig press (80). In one example, the electrode terminal (30) is held in the heating jig press (80) while heated and can be further heated by the heating jig press (80). In another example, the electrode terminal (30) can be heated while held in the heating jig press (80). In yet another example, the electrode terminal (30) can be held in the heating jig press (80) after being heated.

[0119] Various heating methods can be applied to the above electrode terminal (30), such as heater heating and induction heating.

[0120] The electrode terminal (30) may be heated to a temperature higher than the melting point of the first current collector (23-1) but lower than the melting point of the electrode terminal (30). The heating temperature of the electrode terminal (30) may be slightly higher than the melting point of the first current collector (23-1). The heating temperature may be determined within a range where the thin tip of the first current collector (23-1) can be melted instantaneously and immediately welded to the electrode terminal (30).

[0121] The heating jig press (80), while holding the heated electrode terminal (30), presses the first current collector (23-1) axially inward so that the bottom surface of the current collector plate portion (31) of the electrode terminal (30) faces the first current collector (23-1). Accordingly, as shown in FIGS. 5 and FIGS. 8, the tip of the first current collector (23-1) can be welded to the electrode terminal (30).

[0122] The first collector (23-1) may be partially folded and flattened by the pressure of the heating jig press (80).

[0123] Referring to FIG. 7, the lead (16) can be held in a heating jig press (80). In one example, the lead (16) is held in the heating jig press (80) while heated and can be further heated by the heating jig press (80). In another example, the lead (16) can be heated while held in the heating jig press (80). In yet another example, the lead (16) can be held in the heating jig press (80) after being heated.

[0124] Various heating methods can be applied to the above lead (16), such as heater heating and induction heating.

[0125] The lead (16) may be heated to a temperature higher than the melting point of the second current collector (23-2) but lower than the melting point of the lead (16). The heating temperature of the lead (16) may be slightly higher than the melting point of the second current collector (23-2). The heating temperature may be determined within a range where the thin tip of the second current collector (23-2) can be melted instantaneously and immediately welded to the lead (16).

[0126] The heating jig press (80), while holding the heated lead (16), presses the second collector (23-2) axially inward so that the bottom surface of the collector plate portion (31) of the lead (16) faces the second collector (23-2). Accordingly, as shown in FIGS. 6 and FIGS. 8, the tip of the second collector (23-2) can be welded to the lead (16).

[0127] The above second collector (23-2) may be partially folded and flattened by the pressure of the heating jig press (80).

[0128] In order to minimize the effect of heat from the electrode terminal (30) and / or the lead (16) being transferred to the electrode assembly (20) and affecting the electrode assembly (20) during the process of welding the electrode terminal (30) and / or the electrode assembly (20) and / or welding the lead (16) and the electrode assembly (20), the outer circumference of the electrode assembly (20) can be held with a cooling jig holder (70).

[0129] In order to support the electrode assembly (20) during the welding process of the electrode terminal (30) and the electrode assembly (20), a jig holder that fixes and supports the electrode assembly (20) may be used. According to an embodiment, the electrode assembly (20) may be held by a cooling jig holder (70) that has a cooling function added to the jig holder. Although not illustrated, for example, the cooling jig holder (70) may be provided with a passage through which a cooling fluid or refrigerant flows inside. In addition to this, various known cooling methods for cooling the jig holder may be applied.

[0130] In an embodiment, the diameter of the electrode terminal (30) may be smaller than the diameter of the electrode assembly (20).

[0131] In an embodiment, the diameter of the lead (16) may be larger than the diameter of the electrode assembly (20).

[0132] The housing (10) may include a metal can. Referring to FIG. 9, 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 be in the shape of a flat disc intersecting the axial direction, and the side wall (11) may be in the shape of a circular tube extending along the axial direction.

[0133] Preferably, the side wall (11) and the first end wall (12) of the can (10) can be connected in a monolithic form.

[0134] The first end wall (12) and the 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 then 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. For example, the side wall (11) and the first end wall (12) may be manufactured as separate parts and then connected to form an integrated unit by means such as welding.

[0135] A terminal hole (13) is provided in the first end wall (12). The terminal hole (13) is provided at the center of the first end wall (12).

[0136] The diameter of the electrode assembly (20) may be smaller than the inner diameter of the side wall (11).

[0137] The diameter of the electrode terminal (30) may be smaller than the inner diameter of the side wall (11).

[0138] The diameter of the lead (16) may be slightly larger than the inner diameter of the side wall (11) and equal to or slightly smaller than the outer diameter of the side wall (11). The lead (16) may be connected to the axial second end of the side wall (11) and function as a second end wall (16) that blocks the opening of the side wall (11).

[0139] Referring to FIGS. 5, 8, 10, and 11, the electrode terminal (30) is provided with a current collecting plate portion (31) that extends in a radial direction and is welded to the first current collector (23-1). In an embodiment, the current collecting plate portion (31) is implemented in the shape of a flat disc. However, as previously explained, the height of the non-removable portion (26) that functions as the first electrode tab (27-1) in the first current collector (23-1) may change as it moves from the core side to the outer periphery side, and the shape of the current collecting plate portion (31) may be determined in a corresponding shape.

[0140] The electrode terminal (30) further comprises a neck portion (32) extending axially outward from the center of the current collector plate portion (31).

[0141] The neck portion (32) may be manufactured integrally with the current collection plate portion (31) in a monolithic form, or manufactured as a separate part and then combined with the current collection plate portion (31).

[0142] The neck portion (32) may be joined to the current collector portion (31) after the current collector portion (31) is welded to the non-contact portion (26) of the first current collector (23-1). Alternatively, the neck portion (32) may first be integrated with the current collector portion (31), and then the current collector portion (31) may be welded to the non-contact portion (26).

[0143] This can be determined by considering the thickness and rigidity of the current collector plate (31), the connection structure between the current collector plate (31) and the neck portion (32), etc.

[0144] Preferably, the neck portion (32) may be in the shape of a cylinder. The shape of the neck portion (32) may correspond to the shape of the terminal hole (13) of the first end wall (12) and may have a cross-section slightly smaller than that of the terminal hole (13).

[0145] The neck portion (32) can be substantially concentrically aligned with the core hollow portion (29) of the electrode assembly (20) in the axial direction.

[0146] The electrode assembly (20) is inserted into the can (10) while welded to the electrode terminal (30) and lead (16).

[0147] According to an embodiment, the electrode assembly (20) can be inserted axially into the can (10) through an opening provided at the axial second end of the can (10) such that the electrode terminal (30) faces the inner surface of the first end wall (12). Accordingly, the neck portion (32) can be inserted through the terminal hole (13) of the first end wall (12).

[0148] An insulator (19) that electrically insulates the electrode terminal (30) and the first end wall (12) may be interposed between the electrode terminal (30) and the first end wall (12) in the axial direction. Specifically, a flat, donut-shaped insulator (19) may be interposed between the current collector plate (31) and the first end wall (12).

[0149] Additionally, when inserting the neck portion (32) into the terminal hole (13), a gasket (40) may be interposed between the first end wall (12) and the electrode terminal (30). The gasket (40) electrically insulates the electrode terminal (30) and the first end wall (12) and can seal the terminal hole (13) of the first end wall (12).

[0150] The above gasket (40) may have an "L" shaped cross-section in the circumferential direction as shown in FIG. 10 and FIG. 11. The axial extension of the above gasket (40) is interposed radially between the neck portion (32) and the inner surface of the terminal hole (13), and the radial extension of the above gasket (40) is interposed axially between the current collector plate portion (31) and the first end wall (12).

[0151] Referring to FIG. 11, the edge of the lead (16) and the axial second end of the side wall (11) can be welded along the circumferential direction while being radially aligned and axially in close contact. The welding can be performed by scanning a laser (L) along the seam of the lead (16) and the side wall (11).

[0152] If necessary, in order to minimize the effect of the heat generated in the welding process on the electrode assembly (20) on the electrode terminal (30) and the lead (16), the outer circumference of the axial second end of the side wall (11) can be held with the cooling jig holder (70), just as the electrode assembly (20) was held with the cooling jig holder (70) during the process of welding the electrode assembly (20) to the electrode terminal (30) and the lead (16).

[0153] The method of sealing the lead (16) to the side wall (11) is not limited to the laser welding method described above. For instance, the present invention does not exclude the application of other welding methods or the application of a method of fixing the lead (16) by forming a beading portion and a crimping portion on the side wall.

[0154] The lead (16) is sealed and bonded to the side wall (11) to form a second end wall (16) of the can (10) with the lead (16), and then an electrolyte can be injected into the can (10). For example, the electrolyte can be injected through an injection port provided in the can (10), the electrode terminal (30), and the lead (16).

[0155] According to an embodiment, the injection port (33) is provided in a form that penetrates the neck portion (32) in the axial direction. Preferably, the injection port (33) is provided in the central portion of the neck portion (32).

[0156] As the neck portion (32) is axially aligned with the core hollow portion (29) of the electrode assembly (20), the injection port (33) can also be aligned with the core hollow portion (29) of the electrode assembly (20). Accordingly, the electrolyte injected through the injection port (33) can rapidly spread into the internal space of the can (10) through the core hollow portion (29) of the electrode assembly (20).

[0157] After injecting the electrolyte through the injection port (33), the injection port (33) can be sealed. For example, the injection port (33) can be sealed by a stopper (34) that is forcibly pressed into the injection port (33).

[0158] Meanwhile, the electrode terminal (30) may further be provided with a head portion (35) that is connected to the neck portion (32) and extends further outward in a radial direction than the neck portion (32). According to an embodiment, the head portion (35) is manufactured as a separate part from the neck portion (32) and then coupled to the neck portion (32).

[0159] The head portion (35) may be positioned on the outside of the first end wall (12). According to an embodiment, the head portion (35) is coupled with the neck portion (32) while the neck portion (32) penetrates the terminal hole (13) and is positioned on the outside of the first end wall (12). At this time, the axial outer end of the gasket (40) is bent outward in a radial direction by the head portion (35) and is compressed axially between the head portion (35) and the first end wall (12).

[0160] According to an embodiment, the plug portion (34) is provided in the head portion (35). Referring to FIG. 12, the process of connecting the head portion (35) to the neck portion (32) to integrate it, the process of compressing the gasket (40), and the process of sealing the injection port (33) can be carried out simultaneously in the process of forcibly pressing the plug portion (34) of the head portion (35) into the injection port (33). That is, according to an embodiment, the assembly work of the battery cell can be reduced.

[0161] The electrode terminal (30) is electrically connected to the first electrode (21) of the electrode assembly (20), and the first end wall (12), side wall (11) and lead (16) of the can (10) are electrically connected to the second electrode (22) of the electrode assembly (20).

[0162] Referring to FIG. 12, it is shown that the diameter of the head portion (35) of the electrode terminal (30) is approximately 1 / 3 of the diameter of the first end wall (12). According to this structure, the surface of the first end wall (12) can have a sufficient area for a bus bar to be joined. Accordingly, the electrode terminal (30) can form a first electrode terminal, and the first end wall (12) can form a second electrode terminal. That is, according to the embodiment, both the first electrode terminal (30) and the second electrode terminal (12) can be disposed at the axial first end of the battery cell.

[0163] However, it is evident that the present invention is not limited to such terminal arrangement. For instance, it is also possible to set the diameters of the terminal hole (13) and the neck portion (32) larger than those shown in FIG. 12, so that a first electrode terminal (30) is provided on the upper part of the battery cell and a second electrode terminal (16) is provided on the lower part of the battery cell.

[0164] Meanwhile, the vent path of the battery cell is provided at the top of the battery cell.

[0165] The vent of the battery cell can be made through the first end wall (12). To this end, the first end wall (12) may be provided with a vent notch (14) extended in the shape of an "O" or "C", as shown in FIGS. 9 to 12. Accordingly, when the pressure inside the battery cell exceeds a predetermined critical pressure level, the vent notch (14) is damaged, and a venting opening can be formed upward from the battery cell.

[0166] To facilitate the welding of the first current collector (23-1), the current collector plate (31) of the electrode terminal (30) may be provided with a thickness that has a certain degree of rigidity. Accordingly, the current collector plate (31) reinforces the rigidity of the first axial end of the battery cell, thereby allowing the thickness of the first end wall (12) to be thinner than the thickness of the lead (16).

[0167] Therefore, when the internal pressure of the battery cell increases, the bulging phenomenon between the current collector plate (31) and the first end wall (12) can be promoted, and accordingly, the welded portion between the current collector plate (31) and the first current collector (23-1) can easily separate. In other words, a CID (current interrupt device) is implemented due to the increase in internal pressure.

[0168] Additionally, as described above, if the diameter of the current collector plate (31) is set to be slightly smaller than the diameter of the vent notch (14), the force acting on the can when the internal pressure of the battery cell rises can be concentrated on the vent notch (14). Therefore, when venting is required, the vent notch (14) can be smoothly broken. Furthermore, when the vent notch (14) is broken and the first end wall (12) is separated, the electrode terminal (30) is fixed to the first end wall (12) and moves together with it, so the electrode terminal (30) can be separated from the electrode assembly (20). That is, a current interrupt device (CID) is implemented according to the vent operation.

[0169] The embodiments described above should be understood as exemplary in all respects and not limiting, and the scope of the invention will be defined by the claims set forth below rather than by the detailed description above. Furthermore, the meaning and scope of the claims set forth below, as well as all modifications and variations derived from equivalents thereof, should be interpreted as being included within the scope of the invention.

[0170] Although the present invention has been described above with reference to the illustrated drawings, the present invention is not limited by the embodiments and drawings disclosed in this specification, and it is obvious that various modifications can be made by a person skilled in the art within the scope of the technical concept of the present invention. Furthermore, even if the effects of the configuration according to the present invention were not explicitly described while describing the embodiments of the present invention above, it is natural to acknowledge that the effects predictable by said configuration should also be recognized.

Claims

1. A jelly-roll type electrode assembly in which a first electrode and a second electrode are wound around an axis with a separator interposed therebetween; An electrode terminal to which the axial end of the first current collector of the first electrode, which protrudes from the axial first end of the electrode assembly and extends axially outward, is welded; A lid to which the axial end of the second current collector of the second electrode, which protrudes from the axial second end of the electrode assembly and extends axially outward, is welded; and A battery cell comprising: a housing having a side wall extending axially and surrounding the perimeter of the electrode assembly; a first end wall connected to a first axial end of the side wall and extending radially, having a terminal hole through which the electrode terminal passes; and a second end wall connected to a second axial end of the side wall and extending radially.

2. A battery cell according to claim 1, wherein the electrode assembly and the housing are cylindrical.

3. A battery cell according to claim 1, further comprising an insulator interposed axially between the electrode terminal and the first end wall.

4. In claim 1, the electrode terminal is: A current collector plate portion that extends in a radial direction and is welded to the first current collector; A neck portion extending axially outward from the current collector plate portion passing through the terminal hole; and A battery cell having a head portion disposed on the outer side of the first end wall, connected to the neck portion, and extended further outwardly in a radial direction than the neck portion.

5. A battery cell according to claim 1, further comprising an injection port for injecting an electrolyte into the housing.

6. In claim 5, the injection port is a battery cell provided at the electrode terminal.

7. A battery cell according to claim 6, wherein the electrode terminal comprises a plug portion that blocks the liquid injection port.

8. The battery cell according to claim 7, wherein the plug portion is disposed on the outer side of the first end wall and provided in a head portion extending radially.

9. A battery cell according to claim 1, wherein the electrode terminal is electrically insulated from the first end wall and is sealedly installed in the terminal hole.

10. A battery cell according to claim 1, wherein the side wall and the first end wall are connected in a monolithic form.

11. A battery cell according to claim 1, wherein the edge of the second end wall and the axial second end of the side wall are seam welded.

12. A method for manufacturing a battery cell according to any one of claims 1 to 11, A method for manufacturing a battery cell comprising the step of aligning the first electrode and the second electrode and the separator such that the first axial end of the first current collector extends further axially outward than the separator and the second axial end of the second current collector extends further axially outward than the separator, and winding the first electrode, the second electrode, and the separator to produce an electrode assembly.

13. A method for manufacturing a battery cell according to claim 12, further comprising the step of, while the electrode terminal is heated to a temperature greater than or equal to the melting point of the first current collector, applying axial pressure to the axial end of the first current collector with the electrode terminal held in a heating jig press to weld the axial end of the first current collector to the electrode terminal.

14. A method for manufacturing a battery cell according to claim 12, further comprising the step of, while the lead is heated to a temperature above the melting point of the second current collector, applying axial pressure to the axial end of the second current collector with the lead held in a heating jig press to weld the axial end of the second current collector to the lead.

15. A method for manufacturing a battery cell according to claim 12, further comprising the step of inserting an electrode assembly, in which the electrode terminal and the lead are welded, into the housing in the axial direction such that the electrode terminal faces the terminal hole in the axial direction.

16. A method for manufacturing a battery cell according to claim 15, further comprising the step of seam welding the edge of the second end wall and the axial second end of the side wall while the electrode assembly is inserted into the housing.

17. A method for manufacturing a battery cell according to claim 16, wherein the welding is performed by scanning and irradiating with a laser.

18. A method for manufacturing a battery cell according to claim 16, further comprising the step of injecting an electrolyte into the housing after seam welding the second end wall and the side wall.

19. A method for manufacturing a battery cell according to claim 18, further comprising the step of injecting an electrolyte into the housing and then sealing the injection port of the electrolyte.

20. A method for manufacturing a battery cell according to claim 19, wherein, when sealing the injection port, a gasket interposed between the electrode terminal and the first end wall is compressed to seal and fix the electrode terminal to the first end wall.

21. A method for manufacturing a battery cell according to claim 13 or 14, wherein, while welding the axial end of the current collector, the periphery of the electrode assembly is gripped with a cooling jig holder near the axial end to cool the electrode assembly.

22. A method for manufacturing a battery cell according to claim 16, wherein, while welding the second end wall to the side wall, the periphery of the axial second end of the side wall is gripped with a cooling jig holder to cool the housing and the electrode assembly.

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