Prismatic secondary battery including stacked cells

Abstract

The battery includes an electrode assembly. The electrode assembly includes a first electrode including a first portion and a first tab extending from the first portion, a separator laminated on the first electrode, and a second electrode including a second portion and a second tab extending from the second portion and laminated on the separator. The battery further includes a current collector assembly including a plate, a first current collector coupled to a proximal end of the plate and including a first part and a second part facing the first part, and a second current collector coupled to a distal end of the plate and including a third part and a fourth part facing the third part. The battery may further include a housing coupled to the plate. The first and second parts of the first current collector may be configured to move in opposite directions to each other.

Description

[Technical Field]

[0001] The present invention relates to a prismatic secondary battery, and more particularly to a prismatic secondary battery including stacked cells and movable current collectors for slidably securing electrodes of the stacked cells.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0018631, filed on February 14, 2022, and all contents disclosed in the documents of said Korean patent application are incorporated herein by reference. [Background technology]

[0003] Unlike primary batteries, secondary batteries are rechargeable and can be miniaturized while still offering high capacity, which is why much research has been conducted on secondary batteries in recent years. The demand for secondary batteries as a power source is increasing due to the development of battery technology, the demand for mobile devices, and the emergence of electric vehicles and energy storage systems (ESS) as a result of growing awareness of the need for environmental protection.

[0004] Secondary batteries can be classified into coin-type batteries, cylindrical batteries, prismatic batteries, and pouch-type batteries depending on the shape of the battery case. The electrode assembly installed inside the battery case of a secondary battery is a rechargeable power generating element having a laminated structure of electrodes and a separator.

[0005] Electrode assemblies can be broadly classified into a jellyroll type in which a sheet-like positive electrode and negative electrode coated with an active material are wound up with a separator interposed between them; a stack type in which multiple positive electrodes and negative electrodes are stacked in sequence with a separator interposed between them; and a stack and folding type in which stack type unit cells are wound up with a long separator film.

[0006] Secondary batteries meet various market needs by combining the shape of the battery case and the shape of the electrode assembly. In particular, in recent years, new market sectors have emerged that use a large number of secondary batteries, such as electric vehicles. As a result, improving productivity by improving yield and reducing costs has become a very important challenge for the mass production of secondary batteries. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Korean Patent Publication No. 10-2019-0102816 (Published September 4, 2019) Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention provides a secondary battery, particularly a prismatic secondary battery, which can improve yield and reduce production costs and has improved safety against swelling that occurs during use. [Means for solving the problem]

[0009] In one exemplary embodiment, the secondary battery according to the present invention includes an electrode assembly including: a first electrode including a first portion and a first tab extending from the first portion; a separator laminated on the first electrode; and a second electrode including a second portion and a second tab extending from the second portion, laminated on the separator; a current collector assembly including: a plate; a first current collector coupled to a proximal end of the plate and including a first part and a second part facing the first part; and a second current collector coupled to a distal end of the plate and including a third part and a fourth part facing the third part; and a housing coupled to the plate, wherein the first tab is located in a first storage space between the first and second parts of the first current collector and the second tab is located in a second storage space between the third and fourth parts of the second current collector, and the first and second parts of the first current collector may be configured to move in opposite directions to each other.

[0010] The first portion of the first electrode may include an active material.

[0011] The first receiving space may be an opening between a proximal end of the first part and a distal end of the second part.

[0012] The second receiving space may be an opening between the proximal end of the third part and the distal end of the fourth part.

[0013] A portion of the first tab can bend toward the first part or the second part.

[0014] A portion of the first tab may be attached to a surface of the first current collector.

[0015] The device may further include a friction reducing element between the first tab and the first part or between the first tab and the second part.

[0016] The first part and the second part may exert pressure against the first tab.

[0017] The plate may include a vent.

[0018] The plate may include the first tab or a terminal electrically coupled to the first tab.

[0019] A side surface of the electrode assembly may be spaced apart from the first current collector or the second current collector.

[0020] An end of the first tab may be coupled to a coupling portion on a surface of the first part or the second part of the first current collector, and an arc may be formed between the coupling portion and the first accommodating space.

[0021] The first tab may be configured to slide between the first receiving spaces.

[0022] The housing may include a terminal electrically coupled to the first tab or the second tab.

[0023] The housing may include a vent.

[0024] Meanwhile, in one exemplary embodiment, a current collector assembly for a secondary battery according to the present invention includes a plate, a first current collector attached to a proximal end of the plate and including a first part and a second part facing the first part, a second current collector attached to a distal end of the plate and including a third part and a fourth part facing the third part, a first accommodating space between the first part and the second part of the first current collector, and a second accommodating space between the third part and the fourth part of the second current collector, and the first part and the second part of the first current collector may be configured to move in opposite directions to each other.

[0025] The plate may include a vent.

[0026] In one exemplary embodiment, a method for manufacturing a secondary battery according to the present invention may include the steps of: providing a stacked electrode assembly, the stacked electrode assembly including: providing a first electrode including a first portion and a first tab extending from the first portion; laminating a separator on the first electrode; and laminating a second electrode including a second portion and a second tab extending from the second portion on the separator; forming a current collector assembly, the stacked electrode assembly including: providing a plate; attaching a second current collector to a proximal end of the plate; and attaching a second current collector to a distal end of the plate, the second current collector including a third portion and a fourth part opposite the third part; separating the first and second parts of the first current collector in opposite directions; inserting the first tab into a first accommodating space between the first and second parts of the first current collector; and inserting the first tab into a second accommodating space between the third and fourth parts of the second current collector.

[0027] The method may further include bending the first tab in a first direction toward the first part or the second part.

[0028] The method may further include attaching one end of the first tab to a surface of the first part or the second part. [Effects of the Invention]

[0029] One example of the present invention can be provided as a stacked battery. In one embodiment, in the manufacture of a stacked electrode assembly, the notching (punching) process for the uncoated portion can be omitted, thereby reducing the yield reduction and process control difficulties caused by the notching process.

[0030] Furthermore, in the stacked battery of the present invention, the uncoated portions of the positive and negative electrodes that function as electrode tabs have excess lengths. This prevents excessive stress from acting on the welded portions even if swelling occurs in the stacked electrode assembly due to battery degradation caused by repeated charging and discharging or impact, thereby preventing breakage of the electrode tabs during use of the secondary battery and improving safety.

[0031] In addition, the present invention uses a clip structure to fix a portion of the electrode tab and slidably guide the movement of the electrode tab due to swelling, so that the electrode tab moves in proportion to the amount of swelling of the stacked electrode assembly. As a result, the excess portion of the electrode tab can effectively respond to the swelling phenomenon of the stacked electrode assembly, and the position and movement of the excess portion can be accurately controlled, thereby eliminating the risk of internal short circuits.

[0032] The technical effects that can be obtained by the present invention are not limited to the effects described above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.

[0033] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical concept of the present invention, and therefore the present invention should not be interpreted as being limited solely to the matters depicted in such drawings. [Brief explanation of the drawings]

[0034] [Figure 1] 1 is an exploded perspective view of a stacked battery according to an exemplary embodiment of the present invention; [Figure 2] Figure 2(a) is a cross-sectional view of a stacked electrode assembly according to an exemplary embodiment of the present invention, and Figure 2(b) is a top-down view of an exemplary anode and cathode according to an embodiment of the present invention. [Figure 3] FIG. 1 is an exploded perspective view of an exemplary battery cell according to an embodiment of the present invention. [Figure 4] 4(a) is a perspective view of an exemplary current collector assembly according to one embodiment of the present invention, and FIG. 4(b) is a perspective view of another exemplary current collector assembly according to one embodiment of the present invention. [Figure 5] FIG. 1 is a perspective view of an exemplary assembled battery cell according to one embodiment of the present invention. [Figure 6] 6A and 6B are partial perspective views of an exemplary battery cell and another exemplary battery cell including a weld, respectively, according to an embodiment of the present invention. [Figure 7] 7A is a partial perspective view of an exemplary battery cell with folded electrode tabs according to one embodiment of the present invention, and FIG. 7B is a partial perspective view of another exemplary battery cell with folded electrode tabs and including welds according to one embodiment of the present invention. [Figure 8] FIG. 1 is a partial perspective view of an exemplary battery cell including multiple stacked electrode assemblies in accordance with an embodiment of the present invention. [Figure 9] FIG. 2 is a cross-sectional view of an exemplary battery cell with an excess length in accordance with one embodiment of the present invention. [Figure 10] FIG. 10 is a cross-sectional view of the example battery cell of FIG. 9 after swelling has occurred, in accordance with one embodiment of the present invention. [Figure 11] FIG. 2 is a cross-sectional view of an exemplary battery cell including multiple stacked electrode assemblies with excess length in accordance with an embodiment of the present invention. [Figure 12] FIG. 2 is a cross-sectional view of an exemplary battery cell including multiple stacked electrode assemblies with excess length and a single weld in accordance with an embodiment of the present invention. [Figure 13] FIG. 2 is a cross-sectional view of an exemplary battery cell including a friction-reducing structure in accordance with an embodiment of the present invention. [Figure 14] FIG. 2 is a cross-sectional view of an exemplary battery cell including another friction-reducing structure in accordance with an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0035] Because the present invention is susceptible to various modifications and can have various embodiments, specific embodiments will be described in detail below.

[0036] However, this is not intended to limit the invention to any particular embodiment, but should be understood to include all modifications, equivalents, or alternatives falling within the spirit and scope of the invention.

[0037] In the present invention, the terms "comprise" and "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the presence or possibility of addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0038] Furthermore, in the present invention, when a layer, film, region, plate, or other portion is described as being "on" another portion, this includes not only the case where it is "directly on" the other portion, but also the case where there is another portion therebetween. Conversely, when a layer, film, region, plate, or other portion is described as being "under" the other portion, this includes not only the case where it is "directly under" the other portion, but also the case where there is another portion therebetween. Furthermore, in this application, being "located on" can include not only the case where it is located at the top, but also the case where it is located at the bottom.

[0039] The present invention relates to a stacked battery, and in one example, unit cells each having a separator interposed between a positive electrode and a negative electrode are stacked one on top of the other, and the positive electrode uncoated portion and the negative electrode uncoated portion of each unit cell include stacked electrode assemblies arranged on opposite sides of each other and current collector plates equipped with positive and negative electrode terminals.

[0040] Here, the current collector plate includes a positive electrode current collector and a negative electrode current collector made of a conductive material, which are electrically connected to the positive electrode terminal and the negative electrode terminal, respectively, at both ends thereof and extend vertically, and the positive electrode current collector and the negative electrode current collector are respectively bonded to the positive electrode uncoated region and the negative electrode uncoated region.

[0041] In particular, according to the present invention, the positive electrode uncoated portion and the negative electrode uncoated portion function as a positive electrode tab and a negative electrode tab, respectively, and the widths of the positive electrode uncoated portion and the negative electrode uncoated portion correspond to the widths of the positive electrode grounded portion and the negative electrode grounded portion, respectively.

[0042] As such, in the stacked electrode assembly according to the present invention, the positive electrode uncoated portion and the negative electrode uncoated portion, which function as the positive electrode tab and the negative electrode tab, do not require a separate notching process. That is, the widths of the positive electrode uncoated portion and the negative electrode uncoated portion correspond to the widths of the positive electrode landed portion and the negative electrode landed portion, respectively. By eliminating the need for a separate notching process to form the electrode tabs, it is possible to eliminate yield reductions and process management difficulties that result from the notching process and improve productivity.

[0043] The present invention, as described above, will now be described in detail by way of example and by way of illustration in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts.

[0044] FIG. 1 is an exploded perspective view of a stacked battery 100 according to one embodiment of the present invention. The stacked battery 100 may include a battery cell 101 and a housing (case) 103. In one embodiment, the battery cell 101 may include a stacked electrode assembly 110 and a current collector assembly 200 coupled to the stacked electrode assembly 110. In one embodiment, the battery cell 101 may be inserted through an opening in the housing 103 and disposed within the housing 103 to form the stacked battery 100. For example, the housing 103 may be a hexahedral battery case with an opening and a space formed to accommodate the battery cell 101, but the shape and size of the housing 103 are not limited thereto.

[0045] In one embodiment, the battery cell 101 may include a venting portion 120. The venting portion 120 is configured to release excess gas generated inside the stacked battery 100 before, during, and / or after operation of the stacked battery 100. The venting portion 120 may be configured to change shape when the internal pressure of the stacked battery 100 exceeds a preset pressure. For example, the venting portion 120 may be made of a material that changes shape or bursts based on the preset internal pressure of the stacked battery 100. This allows excess gas generated inside the stacked battery 100 to be released, thereby reducing the internal pressure of the stacked battery 100. The preset pressure value may be set based on the material of the housing 103 and / or the internal pressure of the battery cell 101.

[0046] 2(a) is a cross-sectional view of a stacked electrode assembly 110 according to one embodiment of the present invention. In one embodiment, as shown in FIG. 2(a), the stacked electrode assembly 110 may include one or more anodes 106, one or more cathodes 108, and one or more separators 107 disposed between the one or more anodes 106 and the one or more cathodes 108. In one embodiment, the one or more anodes 106 may include, for example, a first anode layer 106a, a current collector 106b on the first anode layer 106a, and a second anode layer 106c on the current collector 106b, as shown in FIG. 2(a). In one embodiment, the first anode layer 106a and the second anode layer 106c may include an active material applied to one or more surfaces of the first anode layer 106a and the second anode layer 106c and / or the current collector 106b of the anode 106. Furthermore, the anode 106 may include an uncoated portion 106d. For example, the uncoated portion 106d may include at least a portion of the current collector 106b to which no active material is applied, as shown in FIG. 2(a). In this specification, the uncoated portion may define a portion or all of the uncoated portion to which no active material is applied.

[0047] In one embodiment, one or more cathodes 108 may include, for example, a first cathode layer 108a, a current collector 108b on the first cathode layer 108a, and a second cathode layer 108c on the current collector 108b, as illustrated in FIG. 2A. In one embodiment, the first cathode layer 108a and the second cathode layer 108c may include an active material applied to one or more surfaces of the first cathode layer 108a and the second cathode layer 108c and / or the current collector 108b of the cathode 108. Additionally, the cathode 108 may include an uncoated portion 108d. For example, the uncoated portion 108d may include at least a portion of the current collector 108b to which no active material is applied, as illustrated in FIG. 2A. In this embodiment, the uncoated portion may refer to a part or the entire uncoated portion of the current collector 108b of the cathode 108 to which no active material is applied.

[0048] In one embodiment, the stacked electrode assembly 110 may be a bidirectional electrode assembly in which each anode uncoated portion 106d (e.g., positive electrode uncoated portion) and each cathode uncoated portion 108d (e.g., negative electrode uncoated portion) are on opposite sides of the stacked battery 100.

[0049] FIG. 2B illustrates an exemplary anode 106 and cathode 108 viewed from above and below, in accordance with one embodiment of the present invention. FIG. 2B shows the anode 106 including an anode uncoated portion 106d and an anode landed portion 106e. Additionally, FIG. 2B shows the cathode 108 including a cathode uncoated portion 108d and a cathode landed portion 108e. In one embodiment, as shown in FIG. 2B, the anode uncoated portion 106d and the cathode uncoated portion 108d may be disposed along one side of the anode 106 and the cathode 108, respectively. Unlike the anodes and cathodes of conventional electrode assemblies, the anode 106 and the cathode 108 do not include notches along the sides where the uncoated portions 106d and 108d are provided. This means that in this embodiment, the anode 106 may include an anode uncoated portion 106d over its entire length, as shown in Fig. 2(b). The cathode 108 may also include a cathode uncoated portion 108d over its entire length, as shown in Fig. 2(b). This improves productivity in manufacturing a stacked battery 100 including an anode 106 and a cathode 108 having uncoated portions without any notching.

[0050] 3 is an exploded perspective view of a battery cell 101 according to one embodiment of the present invention. In one embodiment, the battery cell 101 may include a stacked electrode assembly 110 and a current collector assembly 200. The battery cell 101 may have a structure formed by combining the stacked electrode assembly 110 and the current collector assembly 200, as shown in FIG. 1, for example.

[0051] In one embodiment, the current collector assembly 200 may include a plate 201, a positive terminal 210, and a negative terminal 220. The positive terminal 210 and the negative terminal 220 may be disposed on the plate 201 and may have a square shape, but are not limited to this. The current collector assembly 200 may also include a positive current collector 230 and a negative current collector 240, each made of a conductive material. The positive current collector 230 and the negative current collector 240 may collectively be referred to as a clip structure 250. As shown in FIG. 3 , the proximal end of the positive current collector 230 may be connected to one end of the plate 201, and the proximal end of the negative current collector 240 may be connected to the other end of the plate 201. The positive current collector 230 and the negative current collector 240 may be electrically connected to the positive terminal 210 and the negative terminal 220, respectively. As shown in FIG. 3 , the positive electrode current collector 230 and the negative electrode current collector 240 may extend vertically toward the opposite side of the plate 201. As such, the current collector assembly 200 is a flat member including current collectors, which may be inserted into any opening of the housing (or battery case, omitted from FIG. 3 for clarity) 103 and coupled to form a hermetic seal. For example, the current collector assembly 200 may be coupled to an opening formed in the top surface of the battery case (e.g., a hexahedral battery case or housing) 103 to accommodate the battery cell 101. The current collector assembly 200 may be referred to as a cap plate because the plate 201 of the current collector assembly 200 may be located on the top surface of the stacked battery 100 to function as a cap for closing the opening of the housing 103.

[0052] Continuing to refer to FIG. 3 , the stacked electrode assembly 110 may include a positive electrode uncoated portion tab 112 and a negative electrode uncoated portion tab 114. The positive electrode uncoated portion tab 112 may include a plurality of anode uncoated portions (e.g., 106d) of an anode current collector (e.g., 106b). The shapes and sizes of the positive electrode uncoated portion tab 112 and the negative electrode uncoated portion tab 114 may correspond to the shapes of the anode uncoated portion 106d and the cathode uncoated portion 108d, respectively, but are not limited thereto. Furthermore, the negative electrode uncoated portion tab 114 may include a plurality of cathode uncoated portions (e.g., 108d) of a cathode current collector (e.g., 108b). In one embodiment, the positive electrode current collector 230 and the negative electrode current collector 240 can be coupled to the positive electrode uncoated tab 112 and the negative electrode uncoated tab 114 of the stacked electrode assembly 110 to form a battery cell 101 according to one embodiment of the present invention.

[0053] 3 , the positive electrode current collector 230 and the negative electrode current collector 240 may be made of a conductive material. However, it should be noted that the fact that the positive electrode current collector 230 and the negative electrode current collector 240 may each be made of a conductive material does not necessarily mean that the entire positive electrode current collector 230 and the entire negative electrode current collector 240 are made of a conductive material. For example, in some embodiments, only the portions of the positive electrode current collector 230 and the negative electrode current collector 240 that are coupled to or in contact with the positive electrode uncoated portion tab 112 and the negative electrode uncoated portion tab 114 may be made of a conductive material.

[0054] In an embodiment of the present invention, the positive electrode uncoated portion tab 112 and the negative electrode uncoated portion tab 114 may be a positive electrode tab and a negative electrode tab, respectively. Furthermore, the width of the positive electrode uncoated portion tab 112 and the width of the negative electrode uncoated portion tab 114 may correspond to the width of the landed portion of the anode 106 and the width of the landed portion of the cathode 108, for example, as shown in FIG. 2 . By having the widths of the positive electrode uncoated portion tab 112 and the negative electrode uncoated portion tab 114 correspond to the widths of the landed portion of the anode 106 and the landed portion of the cathode 108, a separate notching process for forming the electrode tabs can be omitted. As a result, the present invention essentially eliminates the reduced yield and difficult process control associated with the conventional notching process, thereby improving the productivity of secondary batteries.

[0055] 3 , the positive electrode current collector 230 and the negative electrode current collector 240, hereinafter referred to as clip structure 250, can resiliently or movably secure the positive electrode uncoated portion tab 112 and the negative electrode uncoated portion tab 114, respectively. In the present invention, the clip structure 250 can be defined as any structure resembling a type of tongs or other mechanism that can apply sufficient pressure to join or secure the positive electrode uncoated portion tab 112 and the negative electrode uncoated portion tab 114 to the positive electrode current collector 230 and the negative electrode current collector 240.

[0056] Due to the characteristics of the clip structure 250, the positive electrode uncoated portion tab 112 and the negative electrode uncoated portion tab 114 can be firmly and easily bonded or secured to the positive electrode current collector 230 and the negative electrode current collector 240. In one embodiment, the clip structure 250 is illustrated as having a slit (or opening) 252 or a through-groove formed along the vertical direction of the positive electrode current collector 230 and / or the negative electrode current collector 240. The size and shape of the slit (or opening) 252 are not limited thereto. The positive electrode uncoated portion tab 112 and the negative electrode uncoated portion tab 114 can be inserted or slid into the slit (or opening) 252 of the positive electrode current collector 230 and the negative electrode current collector 240 to be firmly bonded thereto.

[0057] 4(a) and 4(b) are perspective views of a current collector assembly 200 according to another embodiment of the present invention. FIG. 4(a) shows the current collector assembly 200 including a positive current collector 430 and a negative current collector 440, each made of a conductive material. The positive current collector 430 and the negative current collector 440 may be commonly referred to as a clip structure 450. The positive current collector 430 and the negative current collector 440 may be electrically connected to the positive terminal 210 and the negative terminal 220, respectively. In this embodiment, the positive current collector 430 may include a notch 454 at its distal end. Similarly, the negative current collector 440 may include a notch 454 at its distal end. The notch 454 allows the positive electrode uncoated portion tab 112 and / or the negative electrode uncoated portion tab 114 to be easily inserted or slid into the slit (or opening) 452 in the positive electrode current collector 430 and / or the negative electrode current collector 440. Due to the shape and size of the notch 454, the positive electrode uncoated portion tab 112 can be easily inserted into the slit (or opening) 452. This allows the notch 454 to tolerate greater manufacturing tolerances, improving production yield and efficiency.

[0058] FIG. 4B illustrates another embodiment of the current collector assembly 200. In this embodiment, the positive current collector 430 may include a semicircular cutout 456 at its distal end. Similarly, the negative current collector 440 may include a semicircular cutout 456 at its distal end. The semicircular cutout 456 is configured to allow the positive electrode plain portion tab 112 and / or the negative electrode plain portion tab 114 to be inserted or slid into the semicircular cutout 456 of the positive current collector 430 and / or the negative current collector 440. The shape and size of the semicircular cutout 456 allow the positive electrode plain portion tab 112 to be easily inserted or slid into the semicircular cutout 456. The semicircular cutout 456 can thereby tolerate greater manufacturing tolerances, improving production yields and efficiency.

[0059] Figure 5 is a perspective view of a battery cell 101 assembled according to one embodiment of the present invention. As shown in Figure 5, the assembled battery cell 101 may include a stacked electrode assembly 110 that is coupled to a current collector assembly 200 by sliding or inserting a positive electrode uncoated portion tab 112 and a negative electrode uncoated portion tab 114 (omitted from the drawing for clarity) into slits (or openings) 252 in a positive electrode current collector 230 and a negative electrode current collector 240.

[0060] In this embodiment, the positive electrode non-coating tab 112 may be folded toward one side of the positive electrode current collector 230, as shown in FIG. 5 , so that at least a portion of the surface of the positive electrode non-coating tab 112 is bonded to at least a portion of the surface of the positive electrode current collector 230. Although not shown in FIG. 5 for clarity, the negative electrode non-coating tab 114 may be folded toward one side of the negative electrode current collector 240 in a similar manner. By bonding the surfaces of the positive electrode non-coating tab 112 or the negative electrode non-coating tab 114, not only is the bonding strength between the non-coating tabs 112, 114 and the current collectors 230, 240 increased, but greater electrical contact may also be achieved between the non-coating tabs 112, 114 and the current collectors 230, 240.

[0061] 6(a) to 7(b) are views showing various bonding arrangements between the uncoated tabs 112, 114 and the current collectors 230, 240 according to the present invention. For example, FIGS. 6(a) to 7(b) illustrate bonding arrangements or configurations between the positive uncoated tab 112 and the positive current collector 230. Such bonding arrangements or configurations may be equally applied to the negative uncoated tab 114 and the negative current collector 240 on the opposite side. Only one side of the assembled battery cell 101 is shown for clarity of illustration and explanation of such embodiments.

[0062] 6(a) shows an embodiment in which the positive electrode uncoated portion tab 112 can be bonded or fixed to the positive electrode current collector 230 by being inserted or slid into a slit (or opening) 252 in the positive electrode current collector 230. In such an embodiment, no additional steps may be required. This allows this embodiment to provide a relatively simple bonding structure.

[0063] Alternatively, FIG. 6(b) shows an alternative embodiment in which the positive electrode non-coating portion tab 112 can be joined or secured to the positive electrode current collector 230 by being inserted or slid into a slit (or opening) 252 in the positive electrode current collector 230 and welded to or around the welding area W shown in FIG. 6(b). Welding increases the bond strength and improves bond reliability between the positive electrode non-coating portion tab 112 and the positive electrode current collector 230. In such an embodiment, the positive electrode non-coating portion tab 112 can be formed by welding multiple anode non-coating portions (e.g., 106d) together. Additionally, stacked anode non-coating portions 106d of the positive electrode non-coating portion tab 112 can be welded together to the positive electrode current collector 230 at or around the welding area W. In FIG. 6(b), the welding area W is shown as being formed over the entire positive electrode uncoated portion tab 112, but this is merely an example, and it goes without saying that the welding area W may be formed over only a portion thereof.

[0064] 7(a) illustrates that, according to one embodiment of the present invention, the protruding end or corner of the positive electrode uncoated portion tab 112 or the negative electrode uncoated portion tab 114 can be bent toward one side of the clip structure 250 or the current collectors 230, 240. By bending the protruding end of the uncoated portion tabs 112, 114 toward the clip structure 250 or the current collectors 230, 240, the bonding strength between the uncoated portion tabs 112, 114 and the current collectors 230, 240 is further increased, and unnecessary volume or space in the stacked battery 100 is reduced. This increases the capacity of the stacked battery 100 compared to other prismatic secondary batteries of the same or similar size.

[0065] 7(b) illustrates that, similar to the embodiment of FIG. 7(a) described above, the protruding end or corner of the positive electrode non-coating portion tab 112 or the negative electrode non-coating portion tab 114 can be bent toward one side of the clip structure 250. Additionally, the positive electrode non-coating portion tab 112 or the negative electrode non-coating portion tab 114 can be welded to the current collectors 230, 240 or around the periphery of the welding area W, thereby further increasing the bond strength between the non-coating portion tabs 112, 114 and the current collectors 230, 240 and reducing unnecessary volume or space in the stacked battery 100. This increases the capacity of the stacked battery 100 compared to other prismatic secondary batteries of the same or similar size.

[0066] FIG. 8 is a perspective view of a battery cell 101 according to one embodiment of the present invention. In this embodiment, as illustrated in FIG. 8, the battery cell 101 may include a plurality of positive electrode uncoated portion tabs 112, 112′ arranged parallel to one another. In this embodiment, the positive electrode current collector 230 or the negative electrode current collector 240 may include a plurality of portions arranged parallel to one another and perpendicular to the current collector assembly 200 to form a plurality of slits (or openings) 252 (not shown for clarity). As a result, the positive electrode uncoated portion tab 112 or the negative electrode uncoated portion tab 114 may be divided into a plurality of uncoated portion tabs 112, 112′, 114, 114′ corresponding to the number of portions of the positive electrode current collector 230 or the negative electrode current collector 240. The plurality of uncoated portion tabs 112, 112', 114, 114' may be individually coupled or secured via slits (or openings) 252 in the positive electrode current collector 230 or the negative electrode current collector, in accordance with the above-described embodiments of the present invention. While two positive electrode uncoated portion tabs 112, 112' are illustrated in FIG. 8 , the same arrangement or structure may also be applied to the negative electrode uncoated portion tabs 114, 114', in accordance with the above-described embodiments of the present invention. By providing the plurality of slits (or openings) 252 and the plurality of portions of the current collectors 230, 240, stable bonding strength may be maintained between the uncoated portion tabs 112, 114 and the current collectors 230, 240, even if the thickness of the stacked electrode assembly 110 increases. This allows the secondary battery of the present invention to provide flexibility in production and accommodate increased sizes of secondary batteries. In this embodiment, the multiple portions of the current collectors 230, 240 do not necessarily have to comprise multiple structurally independent current collectors 230, 240. For example, as shown in Fig. 8, multiple clip structures 250 or current collectors 230, 240 may be structurally configured by forming multiple slits (or openings) 252 (not shown for clarity of illustration and explanation) in one current collector 230 or 240, as described above.

[0067] Additionally or alternatively, although not shown, the bent structures (or configurations) and welded regions W described in the previous embodiments may be applied to each of the plain portion tabs 112, 114 described in various embodiments of the present invention.

[0068] 9 is a cross-sectional view illustrating the arrangement or configuration of the positive and / or negative electrode uncoated portion tabs 112, 114, relating to the electrode tabs and clip structure 250 or current collectors 230, 240 of the stacked electrode assembly 110. As shown in FIG. 9, the positive electrode uncoated portion tab 112 or the negative electrode uncoated portion tab 114 extends long from the stacked electrode assembly 110 and passes through a slit (or opening) 252. The positive electrode uncoated portion tab 112 or the negative electrode uncoated portion tab 114 may include an excess portion 300, which may have an arc or curved shape, for example, to allow for a change in length based on the amount of swelling caused by the stacked electrode assembly 110.

[0069] Swelling is a phenomenon that can occur in the stacked electrode assembly 110. For example, the stacked electrode assembly 110 may gradually swell over time due to repeated charging and discharging. Swelling can also occur when the lithium ion electrolyte in a conventional battery evaporates during operation. The evaporation of the electrolyte causes internal pressure in the battery, causing the battery to swell or its surface to deform, for example, convexly. Additionally, swelling can cause deformation of the battery case or housing, and in severe cases, can lead to electrolyte leakage from conventional batteries or fire or explosion.

[0070] Swelling can also affect the internal structure of a secondary battery. For example, swelling inside a battery can exert physical stress on the electrode tabs. In a conventional stacked electrode assembly, the electrode tabs (positive and negative electrode tabs) of each of multiple unit cells are connected to electrode terminals (positive and negative terminals) by welding. Therefore, the distance from each unit cell to the electrode terminals can vary depending on the thickness of the stacked electrode assembly. When swelling occurs in a stacked electrode assembly, the relative position of a unit cell from the electrode terminal depends on the distance between the battery cell and the electrode terminal. Therefore, when swelling occurs in a battery cell, a strong tensile force acts on the electrode tabs of battery cells far from the electrode terminals. However, when the electrode tabs and electrode terminals are designed as welds, only minimal space is provided, taking into account manufacturing variations. Therefore, when swelling occurs due to battery deterioration, the electrode tabs subjected to a strong tensile force can easily short-circuit from the attached electrode terminals, and the resulting electrode tab disconnection can adversely affect the safety of the battery.

[0071] 9 , a disconnection or short circuit at the weld 330 between the positive electrode uncoated portion tab 112 and the negative electrode uncoated portion tab 114 due to swelling is prevented by providing an excess portion 300 on the positive electrode uncoated portion tab 112 and the negative electrode uncoated portion tab 114 of the battery cell 101. The length of the excess portion 300 is determined based on the amount of swelling that may occur in the battery cell 101. When the relative positions of the positive electrode uncoated portion tab 112 and the negative electrode uncoated portion tab 114 of the stacked electrode assembly 110, which are electrically connected to the electrode terminals 210 and 220, change due to swelling, the length of the excess portion 300 may change in response to such a change in relative position. As a result, stress applied to the positive electrode uncoated portion tab 112 and the negative electrode uncoated portion tab 114 due to swelling can be significantly reduced or eliminated, even if the relative position of the stacked electrode assembly 110 changes significantly.

[0072] 10 illustrates that the electrode tab 112 or 114 of the battery cell 101 extends from the stacked electrode assembly 110 supported in the slit (or opening) 252 of the clip structure 250. The electrode tabs 112, 114 may be electrically coupled to the electrode terminals 210, 220, and the excess length 300 may have, for example, an arc or curved shape after passing through the slit (or opening) 252 of the clip structure 250. The end of the excess length 300 forms a weld 330 joined to the clip structure 250, and the electrode tab 112 or 114 is electrically coupled to the electrode terminal 210 or 220 via the clip structure 250 through the weld.

[0073] In one embodiment, the clip structure 250 of the present invention may be a component that physically maintains or supports the electrode tabs 112, 114, which may include a bundle or a plurality of anode uncoated portions 106d and cathode uncoated portions 108d, via slits (or openings) 252 regardless of their shapes. For example, as shown in FIG. 10 , the positive electrode uncoated portion tab 112 or the negative electrode uncoated portion tab 114 may be inserted into a slit (or opening) 252 formed in the clip structure 250 so as to be temporarily fixed. In this case, temporary fixation refers to a fixed state in which the positive electrode uncoated portion tab 112 or the negative electrode uncoated portion tab 114 is inserted into the clip structure 250 and is generally fixed in position, but relative movement occurs when a certain level of tensile force is applied.

[0074] The slit (or opening) 252 of the clip structure 250 is a portion that applies pressure to the electrode tab 112 or 114 to temporarily fix it, and the extension portion 300 is formed continuously with the slit (or opening) 252 of the clip structure 250 and is configured to accommodate swelling of the stacked electrode assembly 110. As a result, when the stacked electrode assembly 110 swells and a tensile force is applied to the electrode tab 112 or 114, the excess portion 300 in the slit (or opening) 252 moves toward the stacked electrode assembly 110, thereby significantly reducing the stress applied to the electrode tab 112 or 114. In this embodiment, the lack of a clear distinction between the polarities of the electrode tab 112 or 114, the positive terminal 210, and the negative terminal 220 can be shown to be interchangeable, because the structures of the electrode tab 112 or 114 and the excess portion 300 of the clip structure 250 can be applied without distinguishing between positive and negative electrodes.

[0075] In one embodiment, the excess length portion 300 may form a U-turn (or bent portion) 310 between the slit (or opening) 252 and the weld 330. The U-turn portion 310 may have a gentle curve toward the slit (or opening) 252 of the clip structure 250, thereby reducing resistance that impedes movement of the excess length portion 300. In one embodiment, the relative position of the apex of the U-turn portion 310 may change depending on the amount of movement of the excess length portion 300. FIG. 10 exemplarily illustrates the change in the relative position of the electrode tab 112 or 114 supported by the clip structure 250 when swelling occurs in the stacked electrode assembly 110. Compared to FIG. 9 , the thickness of the stacked electrode assembly 110 increases (the thickness increases from d to d′) and the relative movement at the slit (or opening) 252 increases as the stacked electrode assembly 110 moves away from the slit (or opening) 252 of the clip structure 250. For example, if the distance D1 is approximately 0.1 to 50 mm, preferably approximately 1 to 10 mm, when the relative position of the stacked electrode assembly 110 changes due to swelling, the apex position of the U-turn portion 310 can change so that the distance D2 is approximately 0.1 to 20 mm, preferably approximately 0.5 to 5 mm. Therefore, the excess length portion 300 can move to accommodate the movement of the electrode tab 112 or 114, thereby preventing the electrode tab 112 or 114 from being disconnected. In this embodiment, the middle portion of the electrode tab 112 or 114 is supported by the clip structure 250, and the movement of the electrode tab 112 or 114 due to swelling is guided to a sliding motion, so that the electrode tab 112 or 114 can be precisely designed to move only by the swelling level. This allows the excess length 300 of the electrode tab 112 or 114 to effectively accommodate the swelling phenomenon of the stacked electrode assembly 110, and the position and movement of the excess length 300 can be precisely controlled to significantly reduce or eliminate the risk of internal short circuits and the like.

[0076] 11, a plurality of stacked electrode assemblies 110 may be provided in one battery cell 101. In such a case, the positive electrode uncoated portion tabs 112 and the negative electrode uncoated portion tabs 114 extending from the plurality of stacked electrode assemblies 110 may be inserted through slits (or openings) 252 of the clip structure 250 that are independent of each other.

[0077] FIG. 11 illustrates that multiple stacked electrode assemblies 110 can be supported by multiple clip structures 250. This means that multiple clip structures 250 can be provided based on the number of stacked electrode assemblies 110, and each stacked electrode assembly 110 can be supported by a slit (or opening) 250 in the corresponding clip structure 250. One end of an excess portion 300 provided on the electrode tab 112 or 114 extending from each stacked electrode assembly 110 can form a weld 330 with the clip structure 250 supporting the electrode tab 112 or 114. This means that the embodiment shown in FIG. 11 can correspond to an embodiment in which multiple stacked electrode assemblies 110 are arranged in parallel. Alternatively, an embodiment in which multiple stacked electrode assemblies 110 are supported by a single clip structure 250 is also possible.

[0078] 12 , one clip structure 250 may have a plurality of slits (or openings) 252 corresponding to the number of stacked electrode assemblies 110, and each stacked electrode assembly 110 may be supported by a corresponding slit (or opening) 252. One end of any extension 300 provided on the electrode tab 112 or 114 extending from the stacked electrode assembly 110 may form one weld 330. This means that multiple extensions 300 may be welded together to form a single weld 330. Reducing the number of welds 300 may result in improved production efficiency.

[0079] In one embodiment, the excess length portion 300 may include a U-turn portion 310 between the slit (or opening) 252 and the weld portion 330, as described above, for each electrode tab 112, 114 extended from the multiple stacked electrode assemblies 110.

[0080] In one embodiment, the clip structure 250 may further include a structure that reduces friction that occurs when the excess length portion 300 temporarily fixed in the slit (or opening) 252 slides. This is to prevent damage to the electrode tab 112 or 114 due to unintentional strong resistance when the excess length portion 300 slides. Therefore, the clip structure 250 may include a friction-reducing structure 340 on the contact surface of the slit (or opening) 252. By providing the friction-reducing structure 340 on the contact surface of the slit (or opening) 252 that presses against the electrode tab 112 or 114, the excess length portion 300 can slide smoothly.

[0081] The friction-reducing structures 340 provided in the slits (or openings) 252 may be embodied in various shapes or forms. For example, as shown in FIG. 13 , embossing structures 342 provided in the slits (or openings) 252 of the clip structure 250 may function as the friction-reducing structures 340. The embossing structures 342 having a hemispherical shape reduce the contact area between the electrode tabs 112 or 114, thereby reducing the sliding resistance. However, the embossing structures 342 are not limited to a hemispherical shape, and various other types of protruding structures may also be applied and function as the friction-reducing structures 340.

[0082] 11, a low-friction coating layer 344 is applied as the friction-reducing structure 340. Here, the term "low-friction coating layer 344" is defined as any coating layer that reduces the coefficient of friction of a surface. For example, a chemically stable Teflon coating layer or a mechanically excellent DLC (Diamond-Like Carbon) coating layer may be applied.

[0083] The present invention has been described in more detail above with reference to the drawings and embodiments, etc. However, the configurations described in the drawings or embodiments in this specification are merely one embodiment of the present invention and do not represent all of the technical ideas of the present invention, so it should be understood that there may be various equivalents and modifications that can replace them at the time of filing this application. [Industrial Applicability]

[0084] The present invention is suitable for application to secondary batteries with increased capacity. [Explanation of symbols]

[0085] 100: Stacked battery 110: Stacked electrode assembly 112: Positive electrode uncoated tab 114: Negative electrode uncoated tab 200: Current collector assembly 210: Positive terminal 220: Negative electrode terminal 230: Positive electrode current collector 240: Negative electrode current collector 250: Clip structure 252: Slit (opening) 300: Extra length 310: U-turn section (bend section) 330: Welded section 340: Friction reduction structure 342: Embossing structure 344: Low friction coating layer W: Welding area

Claims

1. a first electrode including a first landed portion and a first uncoated tab extending from the first landed portion, the first uncoated tab having an excess portion; a separator laminated on the first electrode; and a second electrode including a second landed portion and a second uncoated tab extending from the second landed portion, the second uncoated tab having an excess portion, laminated on the separator; a current collector assembly including a plate, a first current collector coupled to one end of the plate, the first current collector comprising a pair of plate-like members, and a second current collector coupled to the other end of the plate, the second current collector comprising a pair of plate-like members; and a housing coupled to the plate; Including, the first non-coating portion tab is located in a first accommodating space provided between the pair of plate-shaped members of the first current collector, the second non-coating portion tab is located in a second accommodating space provided between the pair of plate-shaped members of the second current collector, a first end of the first plain portion tab fixed to the first current collector, the excess portion of the first plain portion tab being slidable through the first accommodating space; and a second end of the second plain portion tab fixed to the second current collector, the excess portion of the second plain portion tab being slidable through the second accommodating space.

2. The secondary battery of claim 1 , wherein the first landed portion of the first electrode includes an active material.

3. The secondary battery according to claim 1 , wherein the first accommodating space is an opening between the pair of plate-shaped members of the first current collector.

4. The secondary battery according to claim 1 , wherein the second accommodating space is an opening between the pair of plate-like members of the second current collector.

5. The secondary battery according to claim 1 , wherein a portion of the first uncoated portion tab is bent toward one of the pair of plate-shaped members of the first current collector.

6. 2. The secondary battery according to claim 1, further comprising a friction-reducing element between the first non-coating portion tab and one of the pair of plate-shaped members of the first current collector, or between the first non-coating portion tab and the other of the pair of plate-shaped members of the first current collector.

7. A secondary battery as described in claim 1, wherein the pair of plate-like members of the first collector apply pressure to the first plain portion tab.

8. 10. The secondary battery of claim 1, wherein the plate includes a vent configured to exhaust excess gas generated inside the secondary battery before, during, and / or after operation of the secondary battery.

9. The secondary battery of claim 1 , wherein the plate includes the first uncoated tab or a terminal electrically coupled to the first uncoated tab.

10. The secondary battery of claim 1 , wherein a side surface of the electrode assembly is spaced apart from the first current collector or the second current collector.

11. an end of the first non-coating portion tab is coupled to a coupling portion on a surface of one of the pair of plate-shaped members of the first current collector; The secondary battery according to claim 1 , wherein an arc is formed between the coupling portion and the first accommodating space.

12. The secondary battery according to claim 11 , wherein the first plain portion tab is configured to slide between the first receiving spaces.

13. The secondary battery of claim 1 , wherein the housing includes a terminal electrically coupled to the first uncoated tab or the second uncoated tab.

14. 10. The secondary battery of claim 1, wherein the housing includes a vent configured to exhaust excess gas generated inside the secondary battery before, during, and / or after operation of the secondary battery.

15. providing a stacked electrode assembly, providing a first electrode including a first land portion and a first plain tab extending from the first land portion, the first plain tab having an excess length; depositing a separator on the first electrode; stacking a second electrode on the separator, the second electrode including a second land portion and a second un-coated tab extending from the second land portion, the second un-coated tab having an excess portion; providing a stacked electrode assembly comprising: forming a current collector assembly, providing a plate; connecting a first current collector, which is a pair of plate-like members, to one end of the plate; connecting a second current collector, which is a pair of plate-shaped members, to the other end of the plate; forming a current collector assembly comprising: Separating the pair of plate-shaped members of the first current collector in opposite directions; inserting the first non-coating portion tab into a first receiving space defined between the pair of plate-shaped members of the first current collector; and inserting the second non-coating portion tab into a second receiving space defined between the pair of plate-shaped members of the second current collector; Including, one end of the first non-coating portion tab is fixed to the first current collector, and the excess portion of the first non-coating portion tab is slidable through the first receiving space; one end of the second non-coating portion tab is fixed to the second current collector, and the excess portion of the second non-coating portion tab is slidable through the second accommodating space.

16. The method of claim 15, further comprising bending the first uncoated portion tab in a first direction toward one of the pair of plate-shaped members of the first current collector.

17. The method of claim 15 , further comprising attaching one end of the first non-coating portion tab to a surface of one of the pair of plate-shaped members of the first current collector.

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