Method for manufacturing electrode assembly

Abstract

The present invention relates to a method for manufacturing an electrode assembly and, more specifically, to a method for manufacturing an electrode assembly, which can secure a degree of freedom in cell design (such as degree of freedom in tab position design) by improving the limitation of conventional stacking technology, solve a separator folding problem, and at the same time, prevent problems such as separator non-cutting due to process tolerances.

Description

Electrode assembly manufacturing method

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0101553, filed August 3, 2023, and Korean Patent Application No. 10-2024-0098745, filed July 25, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a method for manufacturing an electrode assembly, and more particularly, to a method for manufacturing an electrode assembly that can secure freedom in cell design (freedom in tab position design, etc.) by improving the limitations of conventional lamination technology, and can prevent problems such as non-cutting of the separator due to process tolerance while solving the problem of folding of the separator.

[0005] In recent years, rising energy prices due to the depletion of fossil fuels and growing concerns about environmental pollution have made the demand for eco-friendly alternative energy sources essential for future living. Research is continuing into various power generation technologies, such as solar, wind, and tidal power. Furthermore, significant interest is being focused on power storage devices, such as batteries, to more efficiently utilize the generated electricity.

[0006] Moreover, with the technological development and increasing demand for battery-powered electronic mobile devices and electric vehicles, the demand for batteries as an energy source is rapidly increasing, and accordingly, much research is being conducted on batteries that can meet various needs.

[0007] Secondary batteries are attracting significant attention as an energy source for a variety of products, including mobile devices and electric vehicles. These batteries are an excellent energy source that can replace the use of existing fossil fuel-powered products. Furthermore, they are gaining recognition as an eco-friendly energy source because they produce no byproducts from energy use.

[0008] Secondary batteries include an electrode assembly formed by alternately stacking electrodes and separators, and a battery case that accommodates the electrode assembly. Various methods for manufacturing electrode assemblies have existed in the past. For example, stacking, folding, stack-and-folding, jelly-roll, and lamination-and-stack methods are widely known in the industry. Among these, the Z-folding method (or zigzag folding method), which alternately and sequentially arranges at least one negative electrode and at least one positive electrode on one or both sides of a rectangular separator and folds them in a zigzag direction, may be a representative manufacturing method that increases the efficiency of electrode assembly production.

[0009] Figure 1 is a conceptual perspective view illustrating a conventional Z-folding method for manufacturing an electrode assembly.

[0010] Referring to FIG. 1, the Z-folding method manufactures an electrode assembly (90) by folding a long rectangular separator (30) in a zigzag pattern while placing a positive electrode (12) and a negative electrode (11) therebetween. Specifically, the separator (30) is folded once, the positive electrode (12) is placed on the folded separator (30), the separator (30) is folded again on the placed positive electrode (12), and the negative electrode (11) is placed on the folded separator (30). By continuously repeating this, the electrode assembly (90) can be manufactured. The positive electrode (12) and the negative electrode (11) are each attached with a positive electrode tab (12-1) and a negative electrode tab (11-1) in a protruding state so that even when folding is performed with a separator (30), the positive electrode tab (12-1) and the negative electrode tab (11-1) are not completely covered by the separator (30) and are laminated so that at least a portion thereof protrudes outside the separator (30). When the zigzag folding is completed in this way, a completed electrode assembly (90) can be produced. The completed electrode assembly (90) is illustrated at the bottom of Fig. 1. Looking at this electrode assembly (90), the positive electrode tab (12-1) and the negative electrode (11-1) tab have a form in which they are not completely covered by the separator (30) and at least a portion thereof protrudes outside the separator laminate. Accordingly, they have a form in which they can be connected to an external terminal or electrode lead.

[0011] However, the conventional Z-folding method may be problematic when the electrode (11, 12) does not have a simple rectangular shape. For example, when the electrode includes a recessed portion, and when an electrode tab is positioned in the recessed portion, there was a problem if the conventional Z-folding method was applied as is. The reason is that when the separator (30) covers the electrode during the zigzag folding process, the recessed portion of the electrode and the electrode tab positioned there are both covered by the separator (30), so there is a problem that the electrode tab cannot be utilized later. In addition, if an attempt is made to simply cut the separator (30) at the recessed portion to solve this problem, the electrode tab may be cut off or damaged during the cutting process of the separator (30), so the problem has not been solved yet.

[0012] The present invention has been devised to solve the above problems, and the task of the present invention is to provide a method for manufacturing an electrode assembly that can secure freedom in cell design (freedom in tab position design, etc.) by improving the limitations of conventional electrode separator lamination technology.

[0013] In addition, the present invention provides a method for manufacturing an electrode assembly that can solve the problem of folding the separator while manufacturing an electrode assembly by laminating electrode separators and prevent problems such as non-cutting of the separator due to process tolerance.

[0014] The method for manufacturing an electrode assembly according to the present invention comprises a pre-cutting portion forming process of preparing a separator, forming a pre-cutting portion in which a portion of the separator is pre-cut for each unit length of the separator, folding the separator that has undergone the pre-cutting portion forming process, and forming an electrode laminate by interposing an electrode having an electrode tab connection portion in which an electrode tab is connected between the folded separators, a main cutting process of cutting the separator by forming a cutting line connected to the pre-cutting portion so that the separator at a position corresponding to the electrode tab connection portion in the electrode laminate is cut out, and a separator scrap removing process of removing separator scrap cut by the main cutting process.

[0015] The electrode tab connection portion of the electrode has a recessed shape and includes a base side from which the electrode tab protrudes and a side extending from the base side, and the pre-cutting portion forming process may be a process of pre-cutting the separator so that the pre-cutting portion becomes a line shape spaced apart from the base side by a predetermined distance in the state of the electrode laminate.

[0016] The specified distance may be less than the protrusion length by which the electrode tab protrudes from the base edge.

[0017] In the electrode laminate formation process, the process of folding the separator is a process of zigzag folding the separator, and the process of zigzag folding the separator may be a process of zigzag folding the separator so that the separator is folded at each unit length.

[0018] The main cutting process may include a first cutting step of cutting the separator so that a cutting line is formed parallel to the side edge and spaced apart from the side edge by a predetermined distance.

[0019] The main cutting process may include a second cutting step of cutting the separator so that a cutting line is formed that connects the cutting line formed by the first cutting step and the cutting line formed by the pre-cutting portion forming process.

[0020] The second cutting step may be to cut the separator so that the cutting line formed by the second cutting step has a curved shape.

[0021] The second cutting step may be to cut the separator so that the cutting line formed by the second cutting step has a shape that is more recessed in the direction toward the base edge than the cutting line formed by the pre-cutting portion.

[0022] The first cutting step and the second cutting step may be performed sequentially.

[0023] The first cutting step and the second cutting step may be performed simultaneously.

[0024] The main cutting process may be to cut the separator laminate, which is laminated in multiple layers in an electrode laminate state, at once.

[0025] The pre-cutting section forming process may be performed by a laser cutting method or a mold cutting method.

[0026] The main cutting process may be performed by a laser cutting method or a mold cutting method.

[0027] After the main cutting process, a membrane scrap removal process may be further included to remove membrane scrap cut by the main cutting process.

[0028] The electrode assembly manufacturing method according to the present invention can improve the limitations of conventional electrode separator lamination technology and secure freedom in cell design (freedom in tab position design, etc.).

[0029] In addition, the method for manufacturing an electrode assembly according to the present invention can solve the problem of folding of the separator during the process of manufacturing an electrode assembly by laminating an electrode separator, and at the same time prevent problems such as non-cutting of the separator due to process tolerance.

[0030] Figure 1 is a conceptual perspective view illustrating a conventional Z-folding method for manufacturing an electrode assembly.

[0031] Figure 2 is a flowchart schematically showing a method for manufacturing an electrode assembly according to one embodiment of the present invention.

[0032] Figure 3 is a perspective view illustrating a pre-cutting portion forming process in a method for manufacturing an electrode assembly according to one embodiment of the present invention.

[0033] FIG. 4 is a plan view illustrating an electrode inserted into a separator in a method for manufacturing an electrode assembly according to one embodiment of the present invention.

[0034] FIG. 5 is a perspective view illustrating an electrode laminate formation process in a method for manufacturing an electrode assembly according to one embodiment of the present invention.

[0035] FIG. 6 is a perspective view illustrating a main cutting process in a method for manufacturing an electrode assembly according to one embodiment of the present invention.

[0036] Figure 7 is a plan view showing an enlarged portion of the membrane cutting line shown in Figure 6.

[0037] Figure 8 is a perspective view illustrating a separator scrap removal process in a method for manufacturing an electrode assembly according to one embodiment of the present invention.

[0038] FIG. 9 is a plan view illustrating an electrode assembly manufactured according to a method for manufacturing an electrode assembly according to one embodiment of the present invention.

[0039] Figure 10 is an enlarged view showing the dotted box E portion of Figure 9.

[0040] Fig. 11 is a cross-sectional view taken along line A-A' of Fig. 10.

[0041] Fig. 12 is a cross-sectional view taken along line B-B' of Fig. 10.

[0042] Hereinafter, with reference to the attached drawings, preferred embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be implemented in various different forms and is not limited or restricted by the following examples.

[0043] In order to clearly explain the present invention, a detailed description of a part that is irrelevant to the description or a related known technology that may unnecessarily obscure the gist of the present invention has been omitted, and when adding reference signs to components of each drawing in this specification, the same or similar reference signs are attached to the same or similar components throughout the specification.

[0044] In addition, terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0045]

[0046] Electrode assembly manufacturing method

[0047] FIG. 1 is a conceptual perspective view illustrating a conventional Z-folding method for manufacturing an electrode assembly. FIG. 2 is a flowchart schematically illustrating a method for manufacturing an electrode assembly according to an embodiment of the present invention. FIG. 3 is a perspective view illustrating a pre-cutting portion forming process in a method for manufacturing an electrode assembly according to an embodiment of the present invention. FIG. 4 is a plan view illustrating an electrode inserted into a separator in a method for manufacturing an electrode assembly according to an embodiment of the present invention. FIG. 5 is a perspective view illustrating an electrode laminate forming process in a method for manufacturing an electrode assembly according to an embodiment of the present invention. FIG. 6 is a perspective view illustrating a main cutting process in a method for manufacturing an electrode assembly according to an embodiment of the present invention. FIG. 7 is a plan view illustrating an enlarged portion of a separator cutting line illustrated in FIG. 6. FIG. 8 is a perspective view illustrating a separator scrap removing process in a method for manufacturing an electrode assembly according to an embodiment of the present invention.

[0048] Referring to FIG. 2, a method for manufacturing an electrode assembly (100) according to an embodiment of the present invention may be a method for manufacturing an electrode assembly (100) formed by laminating an electrode (110) including an electrode tab connection portion (113) and a separator (130). Here, the electrode tab connection portion (113) may have an inwardly recessed shape. To this end, a method for manufacturing an electrode assembly (100) according to an embodiment of the present invention includes a pre-cutting portion forming process (P1), an electrode laminate forming process (P2), a main cutting process (P3), and a separator scrap removing process (P4).

[0049] Referring to FIG. 3, the pre-cutting portion forming process (P1) may be a process of preparing a separator (130) and forming a pre-cutting portion (131) in which a portion of the separator (130) is pre-cut for each unit length of the separator (130). As illustrated in FIG. 3, this process may be a process of preparing a rectangular separator (130) and forming a pre-cutting portion (131) in which a portion of the separator (130) is pre-cut. This pre-cutting portion forming process (P1) may be performed in a manner of forming pre-cutting portions (131) at regular intervals while the long separator (130) is spread out flat, and may also be performed while bending or folding the separator (130) into a required shape. In addition, it may be performed while unwinding the separator (130) using a roll, and various methods may be possible.

[0050] This pre-cutting section forming process (P1) can be performed using a laser cutting method or a mold cutting method. In addition, the pre-cutting section (131) can be formed for each unit length of the separator, and this unit length can be the same interval as the folding interval when the separator (130) is folded later for manufacturing the electrode laminate (99).

[0051] Referring to FIGS. 4 and 5, the electrode laminate forming process (P2) may be a process of forming an electrode laminate (99) by zigzag-folding a separator (130) that has undergone the pre-cutting part forming process (P1), and interposing an electrode (110) having an electrode tab connecting portion (113) in which electrode tabs are connected between the separators (130) that are folded in a zigzag pattern.

[0052] Fig. 4 illustrates an electrode (110) interposed between separators (130). The electrode (110) may include an anode (110-2) and a cathode (110-1). The electrode (110) may have an inwardly recessed shape and may be provided with an electrode tab connection portion (113) to which an electrode tab is connected. In particular, the electrode tab connection portion (113) may be provided with a rectangular recessed shape. The electrode tab connection portion (113) may include a base side (114) and a side side (115).

[0053] The electrode (110) may have an electrode (110) tab positioned at the electrode tab connection portion (113). In the electrode tab connection portion (113), the base side (114) may be a side from which the electrode tab (111) protrudes. And the side side (115) may be a side extending from the base side (114). The side side (115) and the base side (114) may meet at a predetermined angle. In the present embodiment, the base side (114) and the side side (115) may meet vertically. The positive electrode (110-2) may have a positive electrode tab (111-2), and the negative electrode (110-1) may have a negative electrode tab (111-1).

[0054] Referring to FIG. 5, the electrode laminate forming process (P2) may be a process of manufacturing an electrode laminate (99) by zigzag-folding a rectangular long separator (130) on which a pre-cut portion (131) has already been formed, while interposing the positive electrode (110-2) and the negative electrode (110-1) illustrated in FIG. 4 therebetween. Here, the process of zigzag-folding the separator (130) may be a process of zigzag-folding the separator (130) so that the separator (130) is folded at each unit length as described above. This may be to ensure that each pre-cut portion (131) is matched with each electrode (110).

[0055] Specifically, the separator (130) may be folded once, the positive electrode (110-2) may be placed on the folded separator (130), the separator (130) may be folded again on the placed positive electrode (110-2), and the negative electrode (110-1) may be placed on the folded separator (130). By continuously repeating this, an electrode laminate (99) may be manufactured. A positive electrode tab (111-2) and a negative electrode tab (111-1) are attached to the positive electrode (110-2) and the negative electrode (110-1), respectively, and when folding is performed with the separator (130), the positive electrode tab (111-2) and the negative electrode tab (111-1) are first covered by the separator (130) and then laminated. When the zigzag folding is completed in this way, a completed electrode laminate (99) such as that illustrated at the bottom of FIG. 5 may be manufactured.

[0056] In the electrode laminate (99) thus formed, the pre-cut portion (131) may be in the form of a line spaced apart from the base edge (114) by a predetermined distance (D) (see FIG. 7). Here, the predetermined distance (D) may be smaller than the protrusion length (L) of the electrode tab (111) protruding from the base edge (114). To this end, the pre-cut portion forming process (P1) previously performed may be to pre-cut the separator (130) so that the pre-cut portion (131) becomes a line spaced apart from the base edge (114) by a predetermined distance (D) in the electrode laminate (99) state.

[0057] More specifically, for example, the cathode (110-1) may be larger than the anode (110-2), and the pre-cut portion (131) may be in the form of a line spaced apart by a predetermined distance (D) from the base side (114) of the electrode tab connection portion (113) formed on the cathode (110-1).

[0058] Referring to FIG. 6, the main cutting process (P3) may be a process of cutting the separator (130) with a cutting line (CL) connected to the pre-cutting part (131) so that the separator (130) at a position corresponding to the electrode tab connection part (113) in the electrode laminate (99) is cut off.

[0059] And referring to FIG. 8, the separator scrap removal process (P4) may be a process for removing the separator scrap (150) (Scrap) cut by the main cutting process (P3) after the main cutting process (P3). After completing the separator scrap removal process (P4), the electrode assembly (100) may be manufactured.

[0060] When manufacturing an electrode assembly (100) using the method for manufacturing an electrode assembly (100) according to one embodiment of the present invention as described above, the limitations of conventional lamination technology can be improved, thereby securing the degree of freedom in cell design (degree of freedom in tab position design, etc.).

[0061] Specifically, the conventional cell design did not have a problem when the electrode tab (111) was located outside the separator (130). However, since the electrode tab (111) is provided, for example, in an electrode tab connection portion (113) having a shape recessed into the inside of the electrode (110), it was difficult to cut the separator (130) so that the electrode tab (111) was exposed when the electrode tab (111) was covered with the separator (130) in the electrode laminate (99) state. The electrode tab could be damaged during the cutting process, or a very complex and difficult task could be required to cut it without damaging the electrode tab. This became a limitation on the position design of the electrode tab (111).

[0062] That is, in the conventional technology, if an attempt is made to cut the separator (130) corresponding to the electrode tab connection portion (113) of the electrode (110) while leaving the electrode tab (111) as is, there is a high risk that the cutting line and the electrode tab may overlap, and thus the electrode tab (111) may be damaged or cut, and therefore it is difficult to cut the separator (130) as is.

[0063] Alternatively, to solve this problem, one could consider a case where the separator (130) portion corresponding to the shape of the electrode tab connection portion (113) is completely cut in advance and then folded. However, in the completely cut portion, the tension of the separator (130) disappears, so that a folding defect occurs due to surrounding air current or static electricity during lamination. In particular, a folding defect may easily occur in the portion of the separator (130) corresponding to the corner (K) of the electrode (110) where the electrode tab connection portion (113) begins (see FIG. 8). This is problematic because it can become a factor that hinders mass production and product safety. Therefore, the method for manufacturing an electrode assembly (100) according to an embodiment of the present invention can be considered to solve the folding problem of the separator (130).

[0064] Meanwhile, referring to FIG. 7, in a method for manufacturing an electrode assembly (100) according to one embodiment of the present invention, the main cutting process (P3) may include a first cutting step and a second cutting step.

[0065] The first cutting step may be a step of cutting the separator (130) so that a cutting line is formed parallel to the side edge (115) while being spaced apart from the side edge (115) by a predetermined distance (G). For convenience, the cutting line may be named as follows: a pre-cutting portion (131) formed by the pre-cutting portion forming process may be referred to as a first cutting line (131). When the pre-cutting portion (131) is regarded as a first cutting line (131), the cutting line formed in the first cutting step may be referred to as a second cutting line (132) illustrated in FIG. 7.

[0066] The second cutting step may be a step of cutting the separator (130) so that a cutting line is formed that connects the cutting line (132) formed by the first cutting step and the cutting line (131) formed by the pre-cutting portion forming process (P1). That is, based on FIG. 7, the second cutting step may be a step of cutting the separator (130) so that a third cutting line (133) is formed that connects the first cutting line (131), which is the pre-cutting portion (131), and the second cutting line (132). The first cutting step and the second cutting step may be performed sequentially, or the first cutting step and the second cutting step may be performed simultaneously. Through the first cutting step and the second cutting step, the separator (130) may be cut so that the separator scrap (150) can be completely separated from the electrode laminate (99).

[0067] In the pre-cutting section forming process (P1), if the separator (130) cutting was done by cutting each sheet, the cutting in the main cutting process (P3) (i.e., the first cutting step and the second cutting step) may be done by holding and cutting the separator (130) laminated in multiple layers in the electrode laminate (99) state at once. That is, the separator laminated in which multiple separators (130) are laminated in the lamination direction may be held and cut at once. The specific method of cutting at once in this way may be a laser cutting method or a mold cutting method.

[0068] Referring to FIG. 7, in the main cutting process (P3) according to one embodiment of the present invention, the separation membrane (130) can be cut so that the cutting line formed by the second cutting step, i.e., the third cutting line (133), has a shape that is more indented in the direction toward the base edge (114) than the cutting line by the pre-cutting part (i.e., the first cutting line (131)).

[0069] Based on Fig. 7, the second cutting step for forming the third cutting line (133) may be a method of cutting the separator so that the second cutting line (132) descends further toward the base side (114) than the pre-cutting portion (131) and then rises again to meet the pre-cutting portions (131). If the third cutting line (133) is cut in this way so that it has a shape that is more recessed than the pre-cutting portion (131) in the direction toward the base side (114), the pre-cutting portion (131) and the third cutting line (133) may have a stepped shape.

[0070] As illustrated in FIG. 7, the alignment of the pre-cut portions (131) may not be completely aligned due to the presence of a tolerance during the process of forming the pre-cut portions (131). That is, the plurality of pre-cut portions (131) formed at each location of the separator (130) may not be aligned as a single line after folding due to the presence of a tolerance. As illustrated in FIG. 7, they may appear to be aligned as a plurality of slightly misaligned lines. In this case, in order for the third cutting line (133) to meet all the pre-cut portion (131) lines, it may be necessary to cut so as to pass through all the pre-cut portion (131) lines while going upward from the bottom. In this case, the third cutting line (133) has a shape that is recessed toward the base edge (114).

[0071] If not in that way, and the third cutting line (133) is made to meet the pre-cutting section (131) in a horizontal direction (i.e., in the direction in which the pre-cutting section (131) line extends), there may be a layer of the separator (130) in which the third cutting line (133) does not meet the pre-cutting section (131). Therefore, performing cutting such that the third cutting line (133) goes down in a shape that is more recessed than the pre-cutting section (131) in the direction toward the base edge (114) and then goes up to meet the pre-cutting section (131) may be a method necessary for manufacturing an electrode assembly (100) of superior quality more effectively without cutting defects. Through this, problems such as non-cutting of the separator (130) due to tolerances in the process can be prevented.

[0072] Of course, when forming the second cutting line (132) in the first cutting step, there may be a method in which the second cutting line (132) is cut so that it passes through all the pre-cutting portions (131) at once and a separate second cutting step is not performed. However, in this case, the cutting must be performed so that the second cutting line (132) is relatively farther away from the side (115). In this case, the second cutting line (132) is formed further away from the side. In other words, the length of the separator (130) protruding from the side (115) becomes longer. In this case, unnecessary waste of space may occur in the final product electrode assembly (100).

[0073] Therefore, in the present invention, in the first cutting step, cutting is performed by dropping the second cutting line (132) to an optimal distance (or minimum distance) from the side (115), and in the second cutting step, the third cutting line (133) is lowered and then raised again to form a shape that is more indented than the pre-cutting portion (131) in the direction toward the base side (114), thereby preventing the aforementioned waste of space and achieving optimal space efficiency.

[0074] Meanwhile, in order to perform smooth and fast work, in the second cutting step, the separator (130) can be cut so that the cutting line (133) formed by the second cutting step has a curved shape.

[0075] Meanwhile, although the present embodiment has described a case where the electrode tab connection portion (113) has an inwardly recessed shape, this does not mean that the shape of the electrode tab connection portion (113) is limited thereto, and other shapes may also be included in the scope of the present invention. That is, if the degree of freedom in cell design (degree of freedom in tab position design, etc.) can be secured and production efficiency can be achieved by performing the pre-cutting portion forming process (P1), the present invention can be applied even when the shape of the electrode tab connection portion (113) is not an inwardly recessed shape.

[0076]

[0077] electrode assembly

[0078] Fig. 9 is a plan view illustrating an electrode assembly manufactured according to a method for manufacturing an electrode assembly according to one embodiment of the present invention. Fig. 10 is an enlarged view illustrating a portion E indicated by a dotted box in Fig. 9. Fig. 11 is a cross-sectional view taken along line A-A' of Fig. 10. Fig. 12 is a cross-sectional view taken along line B-B' of Fig. 10.

[0079] Another embodiment of the present invention, an electrode assembly, is different from the previous embodiment in that it relates to an electrode assembly manufactured by the electrode assembly manufacturing method described in the previous embodiment.

[0080] Commonalities with those described in the preceding electrode assembly manufacturing method will be omitted as much as possible, and differences will be described below. In other words, it is self-evident that any details not described in the present electrode assembly embodiment can be supplemented by the contents of the preceding electrode assembly manufacturing method embodiment if necessary.

[0081] Referring to FIGS. 9 and 10, an electrode assembly (100) according to another embodiment of the present invention may include a separator (130) and an electrode (110), and may be in the form of a laminate in which the electrode (110) and the separator (130) are laminated. Here, the separator (130) may have a laminated form in which it is folded in a zigzag pattern, and the electrode (110) may be configured to be interposed between the separators (130). In addition, the electrode (110) may have an electrode tab connecting portion (113) to which the electrode tab is connected. And the electrode (110) may be a positive electrode (110-2) or a negative electrode (110-1). The electrode (110) may have an electrode tab (111). Here, the electrode tab (111) includes a positive electrode tab (111-2) and a negative electrode tab (111-1). The positive electrode (110-2) may have a positive electrode tab (111-2). The negative electrode (110-1) may have a negative electrode tab (111-1). In addition, the electrode tab (111) may be provided at the electrode tab connection portion (113). That is, the electrode (110) may have an electrode tab (111) positioned at the electrode tab connection portion (113). In addition, the separator (130) may be cut in a shape corresponding to the electrode tab connection portion (113) at a position corresponding to the electrode tab connection portion (113). The electrode assembly (100) according to an embodiment of the present invention has such a configuration, thereby improving the limitations of conventional lamination technology and securing the degree of freedom in cell design (such as the degree of freedom in tab position design).

[0082] In the electrode assembly (100) according to an embodiment of the present invention, the electrode (110) may have an electrode tab connection portion (113). Here, the electrode (110) may be, for example, a cathode (110-1).

[0083] And the electrode tab connection portion (113) may have a recessed shape. This electrode tab connection portion (113) may specifically include a base side (114) from which the electrode tab (111) protrudes and a side side (115) extending from the base side (114). And, the protrusion length (L) of the electrode tab (111) protruding from the base side (114) may be smaller than the recessed depth (H) of the electrode tab connection portion (113) measured based on the base side (114) (see FIG. 10).

[0084] And, similarly, referring to FIGS. 9 and 10, the separator (130) having a zigzag-stacked shape may include a first cutting line (131), a second cutting line (132), and a third cutting line (133).

[0085] The first cutting line (131) may have a line shape spaced apart from the base side (114) by a predetermined distance (D). In the method for manufacturing an electrode assembly (100) according to one embodiment of the present invention, a pre-cutting part (131) may be formed on the separator (130) through a pre-cutting part forming process (P1), and the first cutting line (131) may be a cutting line formed by this pre-cutting part forming process (P1).

[0086] Referring to Fig. 10, a predetermined distance (D) that is a distance that the first cutting line (131) is spaced apart from the base side (114) may be smaller than a protrusion length (L) that the electrode tab (111) protrudes from the base side (114). This may be a result of manufacturing the electrode assembly (100) in such a way that, in the pre-cutting part forming process (P1), the pre-cutting part (131) is formed in a line shape that is spaced apart from the base side (114) by a predetermined distance (D), but the predetermined distance is smaller than the protrusion length that the electrode tab (111) protrudes from the base side (114).

[0087] The second cutting line (132) may be a cutting line in the form of a line parallel to the direction in which the side edge (115) extends, spaced apart from the side edge (115) by a predetermined distance (G). The second cutting line (132) may be a cutting line formed by the main cutting process (P3) performed in the method for manufacturing the electrode assembly (100) according to the embodiment of the present invention described above. More specifically, the second cutting line (132) may be a cutting line formed by the first cutting step of the main cutting process (P3).

[0088] The third cutting line (133) may be a cutting line connecting the second cutting line (132) and the first cutting line (131). The third cutting line (133) may be formed to have a shape that is more recessed than the first cutting line (131) in the direction toward the base side (114). Due to this shape, the first cutting line (131) and the third cutting line (133) may have a stepped shape. As described above, the electrode assembly (100) having this shape can prevent problems such as non-cutting of the separator (130) due to process tolerance, and also, since the second cutting line (132) can be formed at an optimal distance (or a minimum distance) from the side side (115), there is no waste of space, and optimal space efficiency can be achieved.

[0089] In order to perform smooth and fast work, in the second cutting step of the main cutting process (P3), the separator (130) can be cut so that the cutting line formed by the second cutting step has a curved shape, and as a result, the third cutting line (133) can be formed to have a curved shape or a shape of a portion of a circle.

[0090] Referring to FIG. 11, in the electrode assembly (100) according to an embodiment of the present invention, based on a longitudinal cross-sectional view of a separator (130) laminate cut along the stacking direction, at a first cutting line (131) position, the separators (130) may have a relatively more uniform electrode (110)-separator (130) overhang value (X1) along the stacking direction. And referring to FIG. 12, at a second cutting line (132) position, the separators (130) may have a relatively more uneven electrode (110)-separator (130) overhang value (X2) along the stacking direction. Here, the electrode (110)-separator (130) overhang value (X) means a distance value from the end of the electrode (110) to the end of the separator (130).

[0091] Specifically, Fig. 11 is a cross-sectional view taken along line A-A' of Fig. 10, showing a cross-section of the separators (130) in the stacking direction at the first cutting line (131). Fig. 12 is a cross-sectional view taken along line B-B' of Fig. 10, showing a cross-section of the separators (130) in the stacking direction at the second cutting line (132).

[0092] Looking at the change in length of the separators (130) in Fig. 11, it can be seen that they have relatively uniform lengths. That is, referring to Fig. 11, it can be seen that the electrode (110)-separator (130) overhang value (X1) at the first cutting line (131) position does not have a large change in the plurality of separators (130) placed in the stacking direction and is relatively uniform. Here, the electrode (110)-separator (130) overhang value may specifically be the cathode-separator overhang value. That is, it may mean the distance value between the end of the cathode (110-1) and the end of the separator (130).

[0093] When considering the electrode (110)-separator (130) overhang value at the first cutting line (131) position, the end of the separator (130) is formed by the first cutting line (131), which is formed in the pre-cutting portion forming process (P1). In the pre-cutting portion forming process (P1), the separator (130) is cut one by one at a set position, so the end position of the separator (130) can be determined consistently. Therefore, except for a fine tolerance, the end of the separator (130) can be formed at a substantially uniform position. Accordingly, the first cutting line (131) position can have a uniform electrode (110)-separator (130) overhang value (X1).

[0094] In contrast, referring to FIG. 12, it can be seen that the electrode (110)-separator (130) overhang value (X2) at the second cutting line (132) position varies and is relatively more uneven among the plurality of separators (130) placed in the stacking direction. Here, the electrode (110)-separator (130) overhang value may specifically be the cathode-separator overhang value. That is, it may mean the distance value between the end of the cathode (110-1) and the end of the separator (130).

[0095] When the electrode (110)-separator (130) overhang value is considered at the second cutting line (132) position, the end of the separator (130) is formed by the second cutting line (132), which is formed in the main cutting process (P3). The main cutting process (P3) may be a method of holding and cutting the separator (130) laminated in multiple layers in the electrode laminate (99) state at once. When the separator (130) laminate is held and cut at once in this manner, the cutting length may vary between the separators (130) laminated in the thickness direction due to the frictional force between the cutting tool and the separator (130), the difference in the contact area between the separators, and the slip phenomenon between the separators (130). Therefore, the end of the separator (130) may be formed at a substantially non-uniform position. Accordingly, the second cutting line (132) position may have a relatively more uneven electrode (110)-separator (130) overhang value (X1).

[0096] Specifically, referring to FIG. 12, based on a cross-sectional view of the membrane laminate along the stacking direction, at the second cutting line (132) position, the membranes (130) may have an electrode (110)-separator (130) overhang value that gradually decreases and then increases along the stacking direction. This may be a shape formed by cutting the membrane (130) laminate, which is laminated in multiple layers in the electrode laminate (99) state, by holding it at once and cutting it from the top and bottom. In addition, when cutting from the top and bottom by a vertically symmetrical cutting mechanism, at the second cutting line (132) position, the laminated membranes (130) may have an electrode (110)-separator (130) overhang value that is vertically symmetrical based on the membrane (135) laminated at the middle height.

[0097] As described above, the electrode assembly (100) implemented by the embodiment of the present invention can secure freedom in cell design (freedom in tab position design, etc.) by improving the limitations of conventional lamination technology, and can prevent problems such as membrane non-cutting due to process tolerance while solving the problem of membrane folding.

[0098]

[0099] secondary batteries

[0100] Meanwhile, a secondary battery may be provided as another embodiment of the present invention. A secondary battery according to an embodiment of the present invention may include the electrode assembly (100) described above and a battery case (not shown) capable of accommodating the electrode assembly (100).

[0101] These secondary batteries can improve the limitations of conventional stacking technology, secure freedom in cell design (freedom in tab position design, etc.), and simultaneously solve the problem of separator folding and prevent problems such as separator miscutting due to process tolerance.

[0102]

[0103] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various embodiments are possible within the scope equivalent to the technical idea of ​​the present invention and the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0104] [Explanation of symbols]

[0105] 99: Electrode laminate

[0106] 90, 100: Electrode assembly

[0107] 110: Electrode

[0108] 11, 110-1: Cathode

[0109] 12, 110-2: Bipolar

[0110] 111: Electrode tab

[0111] 111-1: Negative tab

[0112] 111-2: Positive tab

[0113] 113: Electrode tab connection

[0114] 114: Base change

[0115] 115: Side

[0116] 30, 130: Membrane

[0117] 131: Pre-cutting section, first cutting line

[0118] 132: Second cutting line

[0119] 133: Third cutting line

[0120] 135: Separator laminated at mid-height

[0121] 150: Membrane scrap

[0122] P1: Pre-cutting section formation process

[0123] P2: Electrode laminate formation process

[0124] P3: Main cutting process

[0125] P4: Membrane scrap removal process

Claims

1. A pre-cutting section forming process of preparing a separation membrane and forming a pre-cutting section in which a portion of the separation membrane is pre-cut for each unit length of the separation membrane; An electrode laminate forming process in which the separator that has undergone the above pre-cutting part forming process is folded and an electrode having an electrode tab connecting portion in which an electrode tab is connected is interposed between the folded separators to form an electrode laminate; A main cutting process for cutting the separator by forming a cutting line connected to the pre-cutting section so that the separator at a position corresponding to the electrode tab connection section in the electrode laminate is cut off; and A method for manufacturing an electrode assembly, comprising a separator scrap removal process for removing separator scrap cut by a main cutting process.

2. In claim 1, The electrode tab connection portion of the above electrode has a recessed shape and includes a base side from which the electrode tab protrudes and a side extending from the base side, The above pre-cutting part forming process is, A method for manufacturing an electrode assembly, characterized in that, in the above electrode laminate state, the separator is pre-cut so that the pre-cutting part becomes a line shape spaced apart from the base side by a predetermined distance.

3. In claim 2, A method for manufacturing an electrode assembly, characterized in that the above-described distance is smaller than the protrusion length of the electrode tab protruding from the base side.

4. In claim 1, In the above electrode laminate formation process, The process of folding the above separator is a process of folding the above separator in a zigzag pattern. A method for manufacturing an electrode assembly, characterized in that the process of zigzag folding the separator is performed by zigzag folding the separator so that it is folded at each unit length.

5. In claim 2, The above main cutting process is, A method for manufacturing an electrode assembly, characterized in that it includes a first cutting step of cutting the separator so that a cutting line parallel to the side edge is formed while being spaced apart from the side edge by a predetermined distance.

6. In claim 5, The above main cutting process is, A method for manufacturing an electrode assembly, characterized in that it includes a second cutting step of cutting the separator so that a cutting line is formed that connects the cutting line formed by the first cutting step and the cutting line formed by the pre-cutting part forming process.

7. In claim 6, The second cutting step is: A method for manufacturing an electrode assembly, characterized in that the separator is cut so that the cutting line formed by the second cutting step has a curved shape.

8. In claim 6, The second cutting step is: A method for manufacturing an electrode assembly, characterized in that the separator is cut so that the cutting line formed by the second cutting step has a shape that is more recessed in the direction toward the base edge than the cutting line formed by the pre-cutting part.

9. In claim 6, A method for manufacturing an electrode assembly, characterized in that the first cutting step and the second cutting step are performed sequentially.

10. In claim 6, A method for manufacturing an electrode assembly, characterized in that the first cutting step and the second cutting step are performed simultaneously.

11. In claim 1, The above main cutting process is, A method for manufacturing an electrode assembly, characterized in that a separator laminate laminated in multiple layers is cut at once in the above electrode laminate state.

12. In claim 1, The above pre-cutting part forming process is, A method for manufacturing an electrode assembly, characterized in that it is performed by a laser cutting method or a mold cutting method.

13. In claim 1, The above main cutting process is, A method for manufacturing an electrode assembly, characterized in that it is performed by a laser cutting method or a mold cutting method.

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