Battery cell and bonding device for manufacturing same

Abstract

A battery cell according to an embodiment of the present disclosure includes: an electrode assembly including a plurality of stacked electrodes, a separator interposed between the plurality of electrodes; and a battery case housing the electrode assembly, in which the electrode assembly includes a plurality of electrode tabs each extending from the plurality of electrodes and including an electrode tab bundle portion bonded between the electrodes having the same polarity, and including a pattern portion on at least one surface of the electrode tab bundle portion. The electrode tab bundle portion includes a pattern portion including a plurality of sub-patterns arranged in a row along a horizontal direction and a vertical direction of the electrode tab, respectively, the sub-patterns having a concave shape in a height direction of the electrode tab bundle portion, and corners of the pattern portion include chamfered portions, respectively.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Korean Patent Application No. 10-2022-0121832 filed on September 26, 2022, and Korean Patent Application No. 10-2023-0126956 filed on September 22, 2023, in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference in their entirety.

[0003] The present disclosure relates to an electrode assembly including an electrode tab that minimizes the occurrence of electrode tab disconnection and a joining device for manufacturing the battery cell, and more particularly, to a battery cell having a pattern of a welding portion that minimizes the occurrence of electrode tab disconnection and an electrode tab joining device for manufacturing the battery cell. Background Art

[0004] As a power source for electronic devices such as mobile phones, laptops, wearable devices or electric vehicles, the demand for secondary batteries is increasing. Secondary batteries are classified into nickel-cadmium secondary batteries, nickel-hydrogen secondary batteries and lithium secondary batteries according to the type of electrode, and research and development of lithium secondary batteries with high operating voltage and high energy density per unit weight are being actively carried out.

[0005] According to the shape of a battery case, lithium secondary batteries are classified into square secondary batteries and cylindrical secondary batteries in which an electrode assembly is built in a metal can and pouch-type secondary batteries in which an electrode assembly is built in a pouch case made of an aluminum laminate sheet.

[0006] The electrode assembly may have a stacked type electrode assembly shape in which plate-shaped electrodes having electrode tabs protruding at one or both sides are stacked, and the stacked electrode tabs form an electrode tab bundle and are combined with electrode leads to form electrode terminals.

[0007] To this end, first, the multilayer electrode tabs are connected, and then the joined electrode tabs are joined with the electrode lead. Typically, ultrasonic welding or laser welding is applied as a joining method. In the joining method, when ultrasonic welding is used, a joining area between the electrode tabs and / or between the electrode tabs and the electrode lead is formed according to a protruding pattern shape of a welding head and an anvil.

[0008] On the other hand, due to the process of connecting the electrode tabs to the electrode leads, the connection and fixation of the electrode leads to the external frame, and periodic charging and discharging, vibration, impact, etc., tensile forces are applied to the electrode leads and the electrode tabs, so that the electrode tabs with relatively weak strength are physically disconnected. When disconnection occurs, safety problems such as reduced battery cell capacity and heat generation are likely to occur.

[0009] In order to prevent such a problem, a technology that can improve a joint between electrode tabs or a joint between an electrode tab and an electrode lead to minimize the risk of disconnection is highly desired. Summary of the invention

[0010] Technical issues

[0011] The present disclosure is designed to solve the problems as described above, and an object of the present disclosure is to provide a battery cell that can prevent disconnection of an electrode tab at a welding portion of the electrode tab and a battery cell joining device for manufacturing the battery cell.

[0012] Technical Solution

[0013] According to one embodiment of the present disclosure, a battery cell is provided, comprising: an electrode assembly, the electrode assembly comprising a plurality of stacked electrodes, a separator interposed between the plurality of electrodes; and a battery case, the battery case accommodating the electrode assembly, wherein the electrode assembly comprises a plurality of electrode tabs each formed to extend from the plurality of electrodes, the plurality of electrode tabs comprising an electrode tab bundle portion coupled between electrodes having the same polarity, and wherein at least one surface of the electrode tab bundle portion comprises a pattern portion, the pattern portion comprising a plurality of sub-patterns arranged in a row along the horizontal direction and the vertical direction of the electrode tabs, respectively, the sub-patterns having a concave shape in the height direction of the electrode tab bundle portion, and a corner of the pattern portion comprises a chamfered portion.

[0014] At least the sub-pattern located at the farthest end in the horizontal direction and the vertical direction among the plurality of sub-patterns may be a right triangle or include a chamfered portion.

[0015] A value of a vertical length (H) / horizontal length (W) of the right triangle or chamfered portion of the sub-pattern located at the farthest end may be 0.4 to 0.82.

[0016] A value of a vertical length (H) / horizontal length (W) of the right triangle or chamfered portion of the sub-pattern located at the farthest end may be 0.7.

[0017] The remaining sub-patterns of the plurality of sub-patterns may each be rectangular or square, and sides of the rectangular or square sub-patterns may be arranged parallel to edges of the electrode tab.

[0018] The pattern part may be arranged to be spaced apart from an edge of the electrode tab, and may be arranged to be spaced apart between the sub-patterns.

[0019] The pattern part may be formed at a joining portion between the electrode tab bundle part and the electrode lead.

[0020] The pattern portion has a rectangular shape as a whole, and four corners of the pattern portion may each include a chamfered portion.

[0021] The pattern portion has a rectangular shape as a whole, and among four corners of the pattern portion, two corners facing the electrode lead side may each include a chamfered portion.

[0022] The sub-pattern at the farthest end is a right triangle, the sub-pattern adjacent to the sub-pattern at the farthest end includes a chamfered portion, and the hypotenuse of the right triangle of the sub-pattern at the farthest end and the hypotenuse of the chamfered portion of the adjacent sub-pattern may be located on the same extended line.

[0023] One vertex of a sub-pattern adjacent to the sub-pattern located at the farthest end may be located on an extension line of the hypotenuse of the right triangle of the sub-pattern at the farthest end.

[0024] According to another embodiment of the present disclosure, a battery cell joining device is provided, including a welding head and an anvil for manufacturing a battery cell, the battery cell including: an electrode assembly, the electrode assembly including a plurality of stacked electrodes, a diaphragm inserted between the plurality of electrodes; and a battery shell, the battery shell accommodating the electrode assembly, wherein the welding head includes a welding portion, the welding portion includes a plurality of welding head protrusions, and wherein the welding portion includes a plurality of welding head protrusions arranged in a row along the horizontal direction and the vertical direction of the welding head, respectively, and the corner of the welding portion includes a chamfered portion.

[0025] The uppermost surface of at least the welding head protrusion located at the farthest end in the horizontal direction and the vertical direction respectively among the plurality of welding head protrusions may be a right triangle or include a chamfered portion.

[0026] A value of vertical length (H) / horizontal length (W) of the right triangle or chamfered portion of the uppermost surface of the horn protrusion at the farthest end may be 0.42 to 0.8.

[0027] A value of vertical length (H) / horizontal length (W) of the right triangle or chamfered portion of the uppermost surface of the welding head protrusion located at the farthest end may be 0.7.

[0028] The uppermost surfaces of the remaining welding head protrusions among the plurality of welding head protrusions are each rectangular or square, and respective sides of the rectangle or square of the welding head protrusions may be arranged parallel to the edge of the electrode tab.

[0029] The electrode assembly includes a plurality of electrode tabs each formed to extend from a plurality of electrodes, the plurality of electrode tabs include an electrode tab bundle portion coupled between electrodes having the same polarity, and the battery cell joining device may join the plurality of electrode tabs to form the electrode tab bundle portion.

[0030] The electrode assembly includes a plurality of electrode tabs each formed to extend from a plurality of electrodes, the plurality of electrode tabs include an electrode tab bundle portion coupled between electrodes having the same polarity, and the battery cell engaging device may engage the electrode tab bundle portion with the electrode leads.

[0031] When viewed from above, the weld portion has a rectangular shape as a whole, and four corners of the weld portion may each include a chamfered portion.

[0032] The welded portion may be rectangular as a whole when viewed from above, and two of four corners of the welded portion may each include a chamfered portion.

[0033] The uppermost surface of the welding head protrusion located at the farthest end is a right triangle, the welding head protrusion adjacent to the welding head protrusion located at the farthest end includes a chamfered portion, and the hypotenuse of the right triangle of the welding head protrusion located at the farthest end and the hypotenuse of the chamfered portion of the adjacent welding head protrusion can be located on the same extension line.

[0034] One vertex of a weld head protrusion adjacent to the weld head protrusion located at the most distal end may be located on an extension line of the hypotenuse of the right triangle of the weld head protrusion at the most distal end.

[0035] The battery cell bonding device may be an ultrasonic welding device or a laser welding device.

[0036] Beneficial Effects

[0037] As described above, the present disclosure has the effect of eliminating disconnection that may occur during welding of electrode tabs, thereby reducing the welding defect rate when manufacturing battery cells and reducing the manufacturing cost of battery cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a perspective view of an electrode assembly according to an embodiment of the present disclosure.

[0039] Figure 2 is a side view showing a state in which an electrode tab is located between a welding head and an anvil of a bonding device according to an embodiment of the present disclosure.

[0040] Figure 3 Show Figure 2 A plan view of the welding head, and Figure 4 Shows when the welding head is partially modified Figure 3 Plan view of the welding head.

[0041] Figure 5 and Figure 6 yes Figure 3 A partial enlarged view of the welding head of the bonding device, showing a perspective view and a plan view respectively.

[0042] Figure 7 As another embodiment of the present disclosure, Figure 5 and Figure 6 modification.

[0043] Figure 8 Yet another embodiment of the present disclosure is shown.

[0044] Fig. 9 and Fig.10 Shown when passing Figure 3 The welding pattern portion formed on the electrode terminal piece when the welding head welds the electrode terminal piece, and Fig.11 Shown when passing Figure 4 A welding pattern portion is formed on the electrode terminal piece when the welding head welds the electrode terminal piece.

[0045] Fig.12 It is shown that according to Figure 5 A graph of the tensile strength of the electrode tab bonded to the welding head and the ratio between the vertical length (H) and the horizontal length (W) of the welding head protrusion at the farthest end of the welding head.

[0046] Fig.13 Shown according to the Figure 5 A stress distribution diagram of the electrode terminal tab engaged with the welding head, showing the ratio between the vertical length (H) and the horizontal length (W) of the welding head protrusion at the farthest end of the welding head.

[0047] Fig.14 Comparison of tensile strength and stress distribution graphs between the comparative example and the example (Example 1) of the present disclosure is shown.

[0048] Fig.15 Schematically shown Figure 3 A partial enlarged view of the welding pattern portion of the electrode terminal piece, and

[0049] Figures 16 to 18 is a perspective view of an anvil according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0050] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present disclosure. However, when describing in detail the working principle of the preferred embodiments of the present disclosure, if it is considered that the detailed description of the related known functions or configurations may unnecessarily obscure the subject matter of the present disclosure, the detailed description will be omitted.

[0051] In addition, throughout the drawings, the same or similar constituent elements will be denoted by the same reference numerals. Throughout the specification, when it is described that an element is "coupled" to another element, the element may be "directly coupled" to the other element, or "indirectly coupled" to the other element through a third element. In addition, unless explicitly described to the contrary, the word "include" and variations such as "comprise" or "comprising" will be understood to imply the inclusion of the elements, but not the exclusion of any other elements.

[0052] The electrode assembly according to the present disclosure has such a shape: plate-like electrode plates 104 with electrode tabs protruding on one or both sides are stacked, and a separator is inserted between the plate-like electrode plates 104. Therefore, it can be a stacked electrode assembly in which multiple cathode plates and multiple anode plates are stacked, and the separator is inserted between the cathode plates and the anode plates, a stacked / folded electrode assembly in which stacked unit battery cells of two or three electrodes are wound on the separator at a specific interval, or a laminated / laminated electrode assembly in which multiple unit battery cells are stacked and joined in the vertical direction.

[0053] Electrode tabs protruding from the electrode assembly are welded and joined to form a cathode tab bundle or an anode tab bundle, and are combined with a cathode lead and an anode lead, respectively, to serve as electrode terminals.

[0054] in this regard, Figure 1 A perspective view of an electrode assembly according to the present disclosure is shown.

[0055] Reference Figure 1 For example, the electrode assembly 10 is a stacked type electrode assembly having a structure of stacking plate-shaped electrode plates 104, and the electrode tabs 100 include an electrode tab bundle 100a formed by combining a plurality of electrode tabs 100 in a state of protruding on one side. The electrode tab bundle 100a is combined with an electrode lead 102 and extends to the outside of the battery case to form an electrode terminal. Figure 1 The case where the cathode tab 100 and the anode tab 100 protrude on one side is shown, but the present disclosure is not limited to those shown cases, and various modifications and changes may be made, for example, including the case where the cathode tab 100 and the anode tab 100 each protrude from both sides of the electrode assembly 10. On the other hand, the electrode tab bundle 100a is combined with the electrode lead 102 on the outer surface of the uppermost electrode tab or the outer surface of the lowermost electrode tab.

[0056] Figures 2 to 6 A joining device including a welding head according to an embodiment of the present disclosure is shown. The joining device 200 according to an embodiment of the present disclosure may be an ultrasonic welding device, a laser welding device, or a welding device that performs both ultrasonic welding and laser welding.

[0057] Figure 21 is a side view showing a state in which an electrode terminal piece is located between a welding head and an anvil of a bonding device according to an embodiment of the present disclosure. Figure 2 The bonding device 200 includes a welding head 210 and an anvil 220. The stacked electrode tabs 100 are positioned between the welding head 210 and the anvil 220, and then the electrode tabs 100 are bonded by applying ultrasonic waves or irradiating lasers to form an electrode tab bundle 100a.

[0058] Alternatively, the electrode tab bundle 100a of the electrode tab 100 and the electrode lead 102 partially overlap or superimpose each other, are placed between the welding head 210 and the anvil 220, and then the electrode tab bundle 100a of the electrode tab 100 and the electrode lead 102 are combined by applying ultrasonic waves or irradiating lasers.

[0059] When the joining device 200 is an ultrasonic welding device, it includes an ultrasonic oscillator, an ultrasonic vibrator, an amplifier, a welding head and an anvil. The ultrasonic oscillator converts an alternating current of 60Hz into a high-frequency current of more than 20kHz and supplies it to the ultrasonic vibrator. The ultrasonic vibrator plays a role in converting electrical energy into mechanical energy and is also called a piezoelectric ultrasonic device. That is, the high-frequency current generated by the ultrasonic oscillator is converted into ultrasonic waves by the ultrasonic vibrator, and the ultrasonic waves converted in this way are transmitted to the amplifier. The amplifier amplifies the received ultrasonic waves and transmits them to the welding head. The welding head pressurizes the surface of the electrode terminal piece placed on the anvil to a specific load, and at the same time applies the amplified ultrasonic waves received from the amplifier to the electrode terminal piece, thereby welding a plurality of cathode terminal pieces and a plurality of anode terminal pieces respectively.

[0060] When the joining device 200 is a laser welding device or includes a laser welding device, it includes a laser oscillator, a head unit including an optical system, a welding mask fixture, etc. The laser beam amplified by the oscillator is irradiated to a plurality of cathode tabs or anode tabs or electrode leads fixed to the mask fixture through the head unit, thereby melting and joining them. At this time, the mask fixture may have a convex or concave portion that partially penetrates the protrusion of the welding head and the anvil, so that the laser beam can reach the electrode tab bundle or the shape of the joint between the electrode tab and the electrode lead.

[0061] According to an embodiment of the present disclosure, Figure 2The horn 210 is formed with a plurality of horn protrusions 211 having a trapezoidal or rectangular shape in a vertical cross section, and the anvil 220 may also be formed with a plurality of anvil protrusions 221 having a trapezoidal or rectangular shape in a vertical cross section. In some cases, the horn protrusions 211 and the anvil protrusions 221 may be completely or partially engaged with each other. That is, each convex protrusion of the plurality of horn protrusions 211 may correspond only to the convex portion between the plurality of anvil protrusions 221. In addition, each convex protrusion of the plurality of horn protrusions 211 may correspond to the concave portion between the plurality of anvil protrusions 221, and the concave portion between the plurality of horn protrusions 211 may correspond to each convex protrusion of the plurality of anvil protrusions 221. At this time, for example, the size of the welding surface 221a of the anvil protrusion 221 formed on the anvil 220 may be formed to be smaller than or equal to the size of the welding surface 211a of the horn protrusion 211 formed on the horn 210. If all the centers of the horn protrusions 211 and the anvil protrusions 221 coincide with each other, the spacing between the anvil protrusions 221 is greater than or equal to the spacing between the horn protrusions 211. If the centers of the horn protrusions 211 and the anvil protrusions 221 only partially coincide with each other, or do not completely coincide with each other, the spacing between the anvil protrusions 221 is less than or equal to the spacing between the horn protrusions 211. For reference, Figures 16 to 18 An embodiment of the anvil 220 is shown, but the present disclosure is not limited thereto, and various modifications and changes may be made.

[0062] Figure 3 A plan view of a welding head 210 of a bonding apparatus according to an embodiment of the present disclosure is shown. Figure 4 Show Figure 3 modification. Figure 5 and Figure 6 yes Figure 3 A partial enlarged view of the welding head 210 is shown in perspective view and plan view respectively. Figure 7 Show Figure 5 and Figure 6 Another modification of . Figure 8 Show Figure 5 and Figure 6 Another modification of .

[0063] Fig. 9 and Fig.10 Shown when passing Figure 3 When the welding head 210 welds the electrode terminal tab 100, the welding pattern portion 110 is formed on at least one surface (for example, the upper surface) of the electrode terminal tab 100, and Fig.11 Shown when passing Figure 4 When the welding head 210 ′ welds the electrode terminal tab 100 , a welding pattern portion is formed on the electrode terminal tab 100 .

[0064] Reference Figure 3 The welding head 210 of the bonding device according to the embodiment of the present disclosure includes a welding portion 210a that contacts and presses the portion to be welded (for example, the electrode terminal bundle or the bonding portion between the electrode terminal bundle and the electrode lead). The welding portion 210a of the welding head 210 is composed of a plurality of welding head protrusions 211. More specifically, the welding portion 210a of the welding head 210 has a grid structure in which a plurality of welding head protrusions 211 are arranged in a row in the horizontal direction and the vertical direction, respectively. Figure 3 In the embodiment of the present invention, the welding head protrusion 211 can be modified and changed in various ways, for example, a square on the uppermost surface and a trapezoid in a vertical cross section. In the specification of the present disclosure, the case where the uppermost surface of the welding head protrusion 211 is a square has been described as an example, but the present disclosure is not limited to those illustrated cases, and the welding head protrusion 211 can be modified and changed in various ways, for example, a rectangular on the uppermost surface and a rectangular in a vertical cross section.

[0065] Reference Figure 3 , Fig. 9 and Fig.10 , when welding the electrode terminal tab 100, the edge of the welding portion 210a of the welding head 210 of the bonding device is spaced apart from the edge of the electrode terminal tab 100 by a prescribed distance and is arranged parallel to the edge of the electrode terminal tab 100. In addition, each side of the square of the welding head protrusion 211 is also arranged parallel to the edge of the electrode terminal tab 100. Thus, the edge of the welding pattern portion 110 formed on the electrode terminal tab 100 is arranged parallel to the edge of the electrode terminal tab 100. Each side of the square sub-pattern 111 formed on the electrode terminal tab 100 is also arranged parallel to the edge of the electrode terminal tab 100. That is, the welding pattern portion 110 has a grid structure in which a plurality of square sub-patterns 111 are arranged in a row along the horizontal direction and the vertical direction of the electrode terminal tab 100. At the same time, when the uppermost surface of the welding head protrusion 211 is a rectangle as described above, the sub-pattern 111 of the welding pattern portion 110 formed on the electrode terminal tab 100 is also a rectangle.

[0066] In addition, the sub-pattern 111 formed on the upper surface of the electrode tab 100 is formed by the welding head protrusion 211 of the welding head 210 of the bonding apparatus and thus has a concave shape corresponding to the protruding shape of the welding head protrusion 211 .

[0067] For reference, in the comparative example described later (see Fig.14 ), the welding pattern formed on the electrode terminal tab has a shape in which a plurality of rhombuses are arranged in a row along the horizontal direction and the vertical direction of the electrode terminal tab.

[0068] According to one embodiment of the present disclosure, the welding pattern part 110 is formed on the electrode tab 100. More specifically, it may be formed in the electrode tab bundle 100a to join a plurality of electrode tabs 100. Alternatively, it may be formed to pass through the electrode tab 100 and the electrode lead 102 to join the electrode tab 100 and the electrode lead 102.

[0069] According to an embodiment of the present disclosure, when viewed from above, the welding portion 210a of the welding head 210 is rectangular as a whole, and specifically, the corners of the welding portion 210a of the welding head 210 include chamfered portions. Figure 3 , all four corners of the welding portion 210a of the welding head 210 may include chamfered portions. Figure 3 Modified Figure 4 Among the four corners of the welding portion 210a of the welding head 210, only the two corners facing the main body side of the battery cell (ie, the opposite side facing the electrode lead 102) may include chamfered portions. Figure 4 In the case of Figure 3 The description of the welding head 210 is repeated in part, so refer to Figure 3 Description and detailed description Figure 3 of Figures 5 to 10 .

[0070] According to an embodiment of the present disclosure, at least the uppermost surface of the welding head protrusion 211-1 located at the farthest end may include a right triangle or a chamfered portion. Figure 5 and Figure 6 , showing the case where the uppermost surface of the welding head protrusion 211-1 is a right triangle. Figure 5 and Figure 6In the embodiment, the uppermost surface of the welding head protrusion 211-1 located at the corner of the welding portion 210a of the welding head 210 (i.e., the uppermost surface of the welding head protrusion 211-1 located at the farthest end in the horizontal direction and the vertical direction of the welding head 210, respectively) is a right triangle. At this time, the ratio between the vertical length (H) and the horizontal length (W) of the uppermost surface of the right triangle of the welding head protrusion 211-1 located at the farthest end, i.e., the vertical length (H) / horizontal length (W) value is 0.42 to 0.8, preferably 0.5 to 0.75, more preferably 0.59 to 0.73, and even more preferably 0.7. When the uppermost surface of the welding head protrusion 211-1 includes a chamfered portion, the vertical length (H) / horizontal length (W) value of the chamfered portion can be 0.42 to 0.8, preferably 0.5 to 0.75, more preferably 0.59 to 0.73, and even more preferably 0.7. Similarly, the farthest sub-pattern 111 - 1 of the welding pattern portion 110 formed on the electrode tab 100 is also in a shape corresponding to the uppermost surface of the welding head protrusion 211 - 1 , and is a right triangle or includes a chamfered portion.

[0071] Similarly, the ratio between the vertical length (H) and the horizontal length (W) of the farthest sub-pattern 111-1, that is, the vertical length (H) / horizontal length (W) value is 0.4 to 0.82, preferably 0.48 to 0.78, more preferably 0.57 to 0.75, and even more preferably 0.7. The range of the sub-pattern 111-1 can be slightly wider than the range of the welding head protrusion 211-1. This is because during the ultrasonic welding of the sub-pattern 111-1, due to the ultrasonic vibration, the trace after welding may also remain longer than the welding head. In addition, the length of the spacing I in the horizontal direction between the edge of the electrode terminal 100 and the edge of the welding pattern portion 110 is 0.011 times to 0.1 times the horizontal length of the electrode terminal 100.

[0072] In this regard, refer to Fig.10 , the horizontal length of the electrode terminal piece 100 (W T ) can be 20 mm to 100 mm. At this time, the horizontal length (W P ) is 19.75 to 99.75, and the length in the vertical direction (H P ) may be 1 mm to 10 mm. The length of the sub-pattern 111 in the horizontal direction may be 0.3 mm to 1.8 mm, and the length in the vertical direction may be 0.3 mm to 1.8 mm, and the length in the horizontal direction and the length in the vertical direction of the sub-pattern 111 may be the same.

[0073] On the other hand, after welding, the side surface portion of the welding head protrusion 211 - 1 located at the farthest end may also have an inclined angle so that the welding head 210 may be more easily separated from the electrode tab 100 without being attached to the electrode tab 100 . Figure 5 The case with an inclination angle of 45 degrees is exemplarily shown. However, the present disclosure is not limited to those shown cases, and Figure 7 As shown, the inclination angle of the side surface of the welding head protrusion 211-1 located at the farthest end may also be 90 degrees.

[0074] Reference Figure 8 As another embodiment, the uppermost surface of the welding head protrusion 211-1 located at the farthest end of the welding head 210 is a right triangle, and the uppermost surface of the welding head protrusion 211-2 adjacent thereto includes a chamfered portion. The hypotenuse of the uppermost surface of the right triangle of the welding head protrusion 211-1 located at the farthest end and the hypotenuse of the chamfered portion of the uppermost surface of the welding head protrusion 211-2 adjacent thereto are located on the same extended line. In short, even if Figure 8 In this case, the corner of the welding portion 210a of the welding head 210 has a chamfered shape as described above.

[0075] Thus, the sub-pattern 111-1 located at the farthest end of the welding pattern portion 110 of the electrode terminal tab 100 is a right triangle, and the sub-pattern 111-2 adjacent thereto includes a chamfered portion. The hypotenuse of the right triangle of the sub-pattern 111-1 located at the farthest end and the hypotenuse of the chamfered portion of the adjacent sub-pattern 111-2 are located on the same extension line. The corners of the welding pattern portion 110 of the electrode terminal tab 100 have a chamfered shape.

[0076] Fig.12 It is shown that according to Figure 5 A graph of the tensile strength of the electrode tab 100 showing the ratio between the vertical length (H) and the horizontal length (W) of the welding head protrusion 211-1 at the farthest end of the welding head 210 (i.e., the ratio between the vertical length (H) and the horizontal length (W) of the sub-pattern 111-1 located at the farthest end of the welding pattern part 110). For example, the tensile strength of the electrode tab 100 may be expressed as a force (hereinafter, referred to as "tensile force") applied to the electrode tab before cracks occur while the electrode tab is fixed on one side and the other side is elongated in the length direction. Fig.12 The graph in is a graph obtained using a UTM (LLOYD LS5 model) apparatus when the sample size is 45 mm x 50 mm (width x height), the size of the welding pattern portion is 43.5 mm x 7.5 mm, and the spacing between the fixing fixtures is 15 mm.

[0077] In other words, Fig.12The x-axis of the curve graph in represents the ratio between the vertical length (H) and the horizontal length (W) of the welding head protrusion 211-1 located at the farthest end of the welding head 210 (i.e., the ratio between the vertical length (H) and the horizontal length (W) of the sub-pattern 111-1 located at the farthest end of the welding pattern portion 110), and the y-axis represents the tensile force applied before cracks appear in the electrode terminal 100.

[0078] Specifically, the tensile strength of the electrode tab varies according to the ratio between the vertical length (H) and the horizontal length (W) of the sub-pattern 111-1 located at the farthest end of the welding pattern part 110. Fig.10 , as the ratio between the vertical length (H) and the horizontal length (W) (i.e., the vertical length (H) / horizontal length (W) value increases from 0 to 0.7), the tensile strength gradually increases, and then the tensile strength of the electrode terminal piece is the highest when the vertical length (H) / horizontal length (W) = 0.7. In addition, it can be confirmed that as the vertical length (H) / horizontal length (W) value increases from 0.7 to 1, the tensile strength of the electrode terminal piece decreases.

[0079] Fig.13 Shown according to the Figure 5 The stress distribution diagram of the electrode terminal 100 is a ratio between the vertical length (H) and the horizontal length (W) of the welding head protrusion 211-1 at the farthest end of the welding head 210 (that is, the ratio between the vertical length (H) and the horizontal length (W) of the sub-pattern 111-1 located at the farthest end of the welding pattern part 110). Fig.12 similar, Fig.13 The stress distribution diagram measured immediately before the occurrence of cracks is shown. First, the portion where the stress concentration is relatively higher than the peripheral portion (hereinafter, referred to as the "stress concentration portion") is indicated by an arrow for reference. Fig.11 As shown, this is mainly formed at the corner of the sub-pattern 111-1 located at the farthest end of the welding pattern portion 110' of the electrode tab 100, and in some cases, it may also be formed at the corner of the sub-pattern 111-2 adjacent to the farthest sub-pattern 111-1.

[0080] In the stress distribution diagram image when the vertical length (H) / horizontal length (W) is 0.2 and 0.4, the stress concentration portion indicated by the arrow is shown at two locations, and in the stress distribution diagram image when the vertical length (H) / horizontal length (W) is 1.0, the stress concentration portion indicated by the arrow is shown at one location.

[0081] On the other hand, in the stress distribution diagram image when the vertical length (H) / horizontal length (W) is 0.7, the stress concentration parts indicated by arrows are shown at four locations, and it can be seen that the stress concentrated parts are more evenly distributed than in the aforementioned cases (i.e., the vertical length (H) / width length (W) is 0.2, 0.4, or 1.0). That is, it can be seen that the stress dispersion level is higher than in the aforementioned cases. From this, it can be seen that the parts with high stress concentration levels are relatively evenly distributed on the electrode terminal 100, thereby reducing the possibility of cracks or fractures due to impact or force applied to the electrode terminal 100. That is, by referring to Fig.11 It can be seen from the stress distribution diagram image in that when the vertical length (H) / horizontal length (W) is 0.7, the tensile strength of the electrode terminal tab 100 is the most excellent.

[0082] In the stress distribution graph, when the vertical length (H) / horizontal length (W) is 0.8, stress concentration parts indicated by arrows are shown at three locations, and it can be seen that the stress dispersion level is higher than when the vertical length (H) / horizontal length (W) is 0.2, 0.4, 0.9 or 1.0, and the tensile strength of the electrode terminal 100 is excellent. In the stress distribution graph image when the vertical length (H) / horizontal length (W) is 0.9, stress concentration parts indicated by arrows are shown at two locations, but it can be seen that the stress at the corner of the sub-pattern 111-2 adjacent to the farthest sub-pattern 111-1 is also slightly higher than the stress at the peripheral portion.

[0083] Reference Fig.14 , in the case where the vertical length (H) / horizontal length (W) = 0.7 as in Example 1, the tensile force immediately before the cracks appear in the electrode terminal tab 100 is 44.4 N. This is greater than the tensile force value of 36.8 N immediately before the cracks appear measured as the comparative example, so it can be confirmed that in the case of the present disclosure, the tensile strength of the electrode terminal tab 100 is superior to that in the comparative example.

[0084] Fig.15 Schematically shown Figure 3 A partial enlarged view of the welding pattern portion 110 of the electrode terminal tab 100. For example, Fig.15 The welding pattern portion 110 may be Figure 5 2 corresponds to the partial enlarged view of the welding head 210 in FIG. As an embodiment of the present disclosure, the vertex C of the sub-pattern 111-2 may be located on the two vertices A and B of the sub-pattern 111-1 at the farthest end, that is, on the extension line of the hypotenuse of the right triangle. Even in this case, the stress distribution level may increase.

[0085] Figures 16 to 18 is a perspective view of an anvil according to an embodiment of the present disclosure.

[0086] like Figures 16 to 18 As shown, the size of the welding surface 221a of the anvil protrusion 221 formed on the anvil 220 is smaller than that of the welding surface 221a formed on the welding head 210 (see Figure 2 ) or the size of a welding surface 211a of a welding head protrusion 211 on the anvil protrusion 221 can be the same as the size of a welding surface 211a of a welding head protrusion 211.

[0087] According to the present disclosure, although not shown here, the corner of the welding portion of the anvil 220 corresponding to the welding portion 210a of the welding head 210 may also have a chamfered shape. Figure 3 As shown in FIG. 1 , when all four corners of the welding portion 210a of the welding head 210 are chamfered, all four corners of the welding portion of the anvil 220 may be chamfered. Figure 3 Modified Figure 4 As shown, among the four corners of the welding portion 210a of the welding head 210, only the two corners facing the main body of the battery cell (i.e., facing the opposite side of the electrode lead 102) are chamfered, and the anvil 220 can also have a shape in which only the two corresponding corners of the welding portion are chamfered.

[0088] Figures 16 to 18 The shape of the anvil protrusion 221 is exemplarily shown, but the combination of the anvil and the horn is not limited to those shown.

[0089] On the other hand, the present disclosure provides a battery module including two or more of the above-mentioned battery cells electrically connected (in series or in parallel). It goes without saying that the number of lithium secondary batteries included in the battery module can be adjusted in various ways in consideration of the use and capacity of the battery module. In addition, the present disclosure provides a battery pack electrically connected to the above-mentioned battery modules according to conventional techniques in the art.

[0090] Such battery modules and battery packs may be used as a power source for any one or more medium or large devices in power tools; electric vehicles including electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs); electric trucks; electric commercial vehicles; or energy storage systems, but are not necessarily limited thereto.

[0091] The above embodiments are merely illustrative of the present disclosure, and it is obvious to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the present disclosure, and these changes and modifications naturally fall within the scope of the appended claims.

[0092] [Explanation of Reference Numerals]

[0093] 10: Electrode assembly

[0094] 100: Electrode terminal block

[0095] 100a: Electrode lug bundle

[0096] 102: Electrode lead

[0097] 104: Electrode plate

[0098] 110, 110': Welding pattern

[0099] 111: Sub-pattern

[0100] 111-1: Sub-pattern located at the farthest end

[0101] 200: Jointing device

[0102] 210: welding head

[0103] 210a: Welding section

[0104] 211: Welding head protrusion

[0105] 211-1: The welding head protrusion at the farthest end

[0106] 220: Anvil

[0107] 221: Anvil protrusion

Claims

1. A battery cell, comprising: An electrode assembly, the electrode assembly comprising a plurality of stacked electrodes, with a separator interposed between the plurality of electrodes; as well as a battery case, the battery case housing the electrode assembly, wherein the electrode assembly includes a plurality of electrode tabs each formed to extend from the plurality of electrodes, the plurality of electrode tabs including an electrode tab bundle portion coupled between electrodes having the same polarity, and Wherein, at least one surface of the electrode terminal sheet bundle portion includes a pattern portion, the pattern portion includes a plurality of sub-patterns arranged in a row along the horizontal direction and the vertical direction of the electrode terminal sheet, the sub-patterns have a concave shape in the height direction of the electrode terminal sheet bundle portion, and the corners of the pattern portion include chamfered portions.

2. The battery cell according to claim 1, wherein: At least the sub-pattern located at the farthest end in the horizontal direction and the vertical direction among the plurality of sub-patterns is a right triangle or includes a chamfered portion.

3. The battery cell according to claim 2, wherein: A value of a vertical length (H) / a horizontal length (W) of the right triangle or the chamfered portion of the sub-pattern located at the farthest end is 0.4 to 0.

82.

4. The battery cell according to claim 3, wherein: The value of the vertical length (H) / the horizontal length (W) of the right triangle or the chamfered portion of the sub-pattern located at the farthest end is 0.

7.

5. The battery cell according to claim 2, wherein: The remaining sub-patterns of the plurality of sub-patterns are each rectangular or square, and Each side of the rectangular or square sub-pattern is arranged parallel to an edge of the electrode tab.

6. The battery cell according to claim 5, wherein: The pattern part is arranged to be spaced apart from an edge of the electrode tab, and is arranged to be spaced apart between the sub-patterns.

7. The battery cell according to claim 1, wherein: The pattern part is formed at a joining portion between the electrode tab bundle part and an electrode lead.

8. The battery cell according to claim 1, wherein: The pattern portion has a rectangular shape as a whole, and four corners of the pattern portion each include a chamfered portion.

9. The battery cell according to claim 1, wherein: The pattern portion has a rectangular shape as a whole, and among the four corners of the pattern portion, two corners facing the electrode lead side each include a chamfered portion.

10. The battery cell according to claim 2, wherein: The sub-pattern at the farthest end is a right triangle, the sub-pattern adjacent to the sub-pattern at the farthest end includes a chamfered portion, and the hypotenuse of the right triangle of the sub-pattern at the farthest end and the hypotenuse of the chamfered portion of the adjacent sub-pattern are located on the same extended line.

11. The battery cell according to claim 2, wherein: One vertex of a sub-pattern adjacent to the sub-pattern located at the farthest end is located on an extension line of the hypotenuse of the right triangle of the sub-pattern located at the farthest end.

12. A battery cell joining device, the battery cell joining device comprising a welding head and an anvil for manufacturing a battery cell, the battery cell comprising: An electrode assembly, the electrode assembly comprising a plurality of stacked electrodes, with a separator interposed between the plurality of electrodes; and a battery case accommodating the electrode assembly, Wherein, the welding head comprises a welding portion, the welding portion comprises a plurality of welding head protrusions, and The welding portion includes a plurality of welding head protrusions arranged in a row along the horizontal direction and the vertical direction of the welding head, respectively, and the corner of the welding portion includes a chamfered portion.

13. The battery cell joining device according to claim 12, wherein: The uppermost surface of at least the welding head protrusion located at the farthest end in the horizontal direction and the vertical direction among the plurality of welding head protrusions is a right triangle or includes a chamfered portion.

14. The battery cell joining device according to claim 13, wherein: The value of the vertical length (H) / horizontal length (W) of the right triangle or the chamfered portion of the uppermost surface of the welding head protrusion located at the farthest end is 0.42 to 0.

8.

15. The battery cell joining device according to claim 14, wherein: The value of the vertical length (H) / the horizontal length (W) of the right triangle or the chamfered portion of the uppermost surface of the welding head protrusion located at the farthest end is 0.

7.

16. The battery cell joining device according to claim 13, wherein: The uppermost surfaces of the remaining welding head protrusions of the plurality of welding head protrusions are each rectangular or square, and Each side of the rectangular or square shape of the welding head protrusion is arranged in parallel with an edge of the electrode tab.

17. The battery cell joining device according to claim 12, wherein: The electrode assembly includes a plurality of electrode tabs each formed to extend from the plurality of electrodes, the plurality of electrode tabs including an electrode tab bundle portion coupled between electrodes having the same polarity, and The battery cell joining device joins the plurality of electrode tabs to form the electrode tab bundle portion.

18. The battery cell joining device according to claim 12, wherein: The electrode assembly includes a plurality of electrode tabs each formed to extend from the plurality of electrodes, the plurality of electrode tabs including an electrode tab bundle portion coupled between electrodes having the same polarity, and The battery cell joining device joins the electrode tab bundle and the electrode lead.

19. The battery cell joining device according to claim 12, wherein: The weld portion has a rectangular shape as a whole when viewed from above, and four corners of the weld portion each include a chamfered portion.

20. The battery cell joining device according to claim 12, wherein: The weld portion has a rectangular shape as a whole when viewed from above, and two of four corners of the weld portion each include a chamfered portion.

21. The battery cell joining device according to claim 13, wherein: The uppermost surface of the welding head protrusion located at the farthest end is a right triangle, the welding head protrusion adjacent to the welding head protrusion located at the farthest end includes a chamfered portion, and the hypotenuse of the right triangle of the welding head protrusion located at the farthest end and the hypotenuse of the chamfered portion of the adjacent welding head protrusion are located on the same extension line.

22. The battery cell joining device according to claim 13, wherein: One vertex of a welding head protrusion adjacent to the welding head protrusion located at the most distal end is located on an extension line of the hypotenuse of the right-angled triangle of the welding head protrusion located at the most distal end.

23. The battery cell joining device according to claim 12, wherein: The battery cell joining device is an ultrasonic welding device or a laser welding device.

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