Electrode assembly and method of manufacturing electrode assembly

Abstract

The present invention provides an electrode assembly comprising: a stack (100) in which a plurality of electrodes (110) and a plurality of separators (120) are alternately stacked in a first direction so as to be aligned; and a wrapping film (200) surrounding the stack (100) and welded to the stack (100) to secure the plurality of electrodes (110) and the plurality of diaphragms (120). The electrode tabs (112) of the plurality of electrodes (110) are provided on one side or the other side of the stack (110) in a second direction intersecting the first direction. The wrapping film (200) surrounds one side and the other side of the stack (100) in the first direction and one side and the other side of the stack (100) in a third direction intersecting the first direction and the second direction, and is welded to at least one side or the other side of the stack (100) in the first direction. Accordingly, deformation and damage of the diaphragm (120), damage of alignment of the stack (100), and a short circuit resulting therefrom can be prevented.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0072076, dated June 14, 2022, and Korean Patent Application No. 10-2023-0074431, dated June 9, 2023, and all contents disclosed in the documents of these patent applications are incorporated as part of this specification.

[0002] The present invention relates to an electrode assembly and a method of manufacturing the electrode assembly, and more particularly, to an electrode assembly and a method of manufacturing the electrode assembly that prevent deformation and damage of a separator, disruption of alignment of stacked pieces, and short circuits caused thereby. Background Art

[0003] Unlike primary batteries, which cannot be recharged, secondary batteries refer to batteries that can be charged and discharged. These secondary batteries are used as power sources in small high-tech electronic devices such as mobile phones, PDAs, and laptop computers, as well as in energy storage systems (ESS), electric vehicles (EV), or hybrid electric vehicles (HEV).

[0004] In order to manufacture these secondary batteries, the negative electrode and the positive electrode are first manufactured by applying the electrode active material slurry to the negative electrode collector and the positive electrode collector, and the negative electrode and the positive electrode are stacked on both sides of the separator to form an electrode assembly of a predetermined shape. Thereafter, the electrode assembly is housed in a battery case, an electrolyte is injected, and the battery case is sealed.

[0005] Various types of electrode assemblies are used in pouch-type secondary batteries. Among these electrode assemblies, a laminated and stacked (L&S) electrode assembly is manufactured by first manufacturing a unit cell using a negative electrode, a separator, and a positive electrode, and then stacking the unit cells.

[0006] Conventionally, since there is no or very weak adhesion between the stacked unit cells, the unit cells often deviate from their original positions, resulting in alignment degradation.

[0007] However, when the tape is attached, the separator is partially bent by the tape, causing damage to the separator or electrode or short circuit. In addition, there is a problem that the tape T is easily separated from the stack of unit cells during the injection process or degassing process of the electrolyte, thereby deforming the separator 120 and causing a short circuit.

[0008] Korean Patent Application Publication No. 10-2021-0127532 discloses an electrode assembly in which a plurality of unit cells are stacked by bonding each other with an adhesive to solve the above-mentioned problems.

[0009] However, in the related art, after applying the adhesive to the unit cells, the unit cells must be aligned and stacked, which increases manufacturing costs and manufacturing time. Summary of the invention

[0010] Technical issues

[0011] In order to solve the above problems, an object of the present invention is to provide an electrode assembly which prevents deformation and damage of a separator, disruption of alignment of a stack, and short circuit caused thereby.

[0012] An object of the present invention is to provide an electrode assembly which securely and directly aligns and fixes electrodes and separators.

[0013] An object of the present invention is to provide an electrode assembly in which a wrapping film is securely coupled to a stack.

[0014] An object of the present invention is to provide an electrode assembly having a simple structure, which can be easily manufactured at low cost, simplifies manufacturing equipment, reduces manufacturing costs, and shortens manufacturing time.

[0015] An object of the present invention is to provide an electrode assembly in which the performance of a secondary battery is not degraded and the life span is not shortened even when a stack is surrounded by a wrap film.

[0016] An object of the present invention is to provide an electrode assembly that increases the energy density of a secondary battery.

[0017] The purpose of the present invention is not limited to the above purpose, and other purposes and advantages of the present invention will be understood through the following description, and will be more clearly understood through the embodiments of the present invention. It should also be easily understood that the purposes and advantages of the present invention can be realized and obtained by the devices described in the attached claims and their combinations.

[0018] Technical Solution

[0019] In order to solve the above problems, the present invention provides an electrode assembly including a stack 100 and a wrapping film 200 .

[0020] The stack 100 may be formed by alternately stacking a plurality of electrodes 110 and a plurality of separators 120 in a first direction.

[0021] The stack 100 may be formed by aligning a plurality of electrodes 110 and a plurality of separators 120 in a first direction and alternately stacking them.

[0022] The wrapping film 200 surrounds the stack 100 and is welded to the stack 100 to fix the plurality of electrodes 110 and the plurality of separators 120 .

[0023] The electrode tab 112 of each of the plurality of electrodes 110 may be disposed on one side or the other side of the stack 100 in a second direction intersecting the first direction.

[0024] The wrapping film 200 surrounds one side and the other side of the stack 100 in the first direction and one side and the other side of the stack 100 in a third direction intersecting the first and second directions, and may be welded to at least one side or the other side of the stack 100 in the first direction.

[0025] In one embodiment, the wrapping film 200 may be welded to one or the other side of the stack 100 in the first direction and one or the other side of the stack 100 in the third direction.

[0026] In one embodiment, the wrapping film 200 may include a first wrapping film 210 and a second wrapping film 220 .

[0027] The first wrapping film 210 may be bent to surround one side of the stack 100 in the first direction, at least a portion of one side of the stack 100 in the third direction, and at least a portion of the other side of the stack 100 in the third direction.

[0028] The first wrapping film 210 may be welded to at least one side of the stack 100 in the first direction.

[0029] The second wrapping film 220 may be bent to surround the other side of the stack 100 in the first direction, at least a portion of one side of the stack 100 in the third direction, and at least a portion of the other side of the stack 100 in the third direction.

[0030] The second wrapping film 220 may have both end portions overlapping both end portions of the first wrapping film 210 in the first direction on one side and the other side of the stack 100 in the third direction.

[0031] The second wrapping film 220 may be welded to at least the other side of the stack 100 in the first direction and both overlapping end portions of the first wrapping film 210 .

[0032] In one embodiment, the first wrapping film 210 may be welded to one side of the stack 100 in the first direction, at least a portion of one side of the stack 100 in the third direction, and at least a portion of the other side of the stack 100 in the third direction.

[0033] In one embodiment, each of the plurality of diaphragms 120 may extend further than the plurality of electrodes 110 adjacent to each of the plurality of diaphragms 120 in one direction and another direction of the third direction.

[0034] When the wrap film 200 is welded to the stack 100 , one end and the other end of at least a portion of the plurality of diaphragms 120 in the third direction may be bent to be close to or contact one end and the other end of the plurality of adjacent diaphragms 120 in the third direction.

[0035] Each of the plurality of diaphragms 120 may extend further than the plurality of electrodes 110 adjacent to each of the plurality of diaphragms 120 in one direction and another direction of the third direction, and

[0036] When the wrapping film 200 is welded to the stack 100, one end or the other end of each of two or more of the plurality of diaphragms 120 stacked continuously in the first direction is bent together in one direction or the other direction of the first direction, wherein one or more of the plurality of electrodes 110 are located between the plurality of diaphragms.

[0037] In one embodiment, the wrapping film 200 may extend in the second direction to surround a region corresponding to a predetermined section S of each of the plurality of diaphragms 120 in the second direction.

[0038] The predetermined section S may be a section extending from the center of each of the plurality of diaphragms 120 in the second direction to one end and the other end of each of the plurality of diaphragms 120 in the second direction.

[0039] In one embodiment, the wrapping film 200 may be welded to at least a portion of one end portion or the other end portion of the plurality of separators 120 in the third direction.

[0040] The wrapping film 200 may be welded to one end or the other end of at least a portion of the plurality of diaphragms 120 in the third direction by a length corresponding to the predetermined section S in the second direction.

[0041] In one embodiment, when the wrapping film 200 is welded to the stack 100 , the first portion P1 of the predetermined section S of one end in the third direction of at least a portion of the plurality of diaphragms 120 may be bent to be close to or contact an adjacent diaphragm 120 .

[0042] Furthermore, at least a second portion P2 of the predetermined section S of the other end in the third direction of each of at least a portion of the plurality of diaphragms 120 may be bent to approach or contact each of the plurality of adjacent diaphragms 120 .

[0043] In one embodiment, the plurality of electrodes 110 may be located at one end or the other end of the stack 100 in the first direction.

[0044] The wrapping film 200 may be welded to one side surface or the other side surface in the first direction of each of the plurality of electrodes 110 located at one end or the other end of the stack 100 in the first direction.

[0045] In one embodiment, the stack 100 may include a plurality of unit cells C aligned and stacked in a first direction.

[0046] Each of the plurality of unit cells C may include a portion of the plurality of electrodes 110 and a portion of the plurality of separators 120 that are alternately stacked.

[0047] A portion of the plurality of electrodes 110 constituting each of the plurality of unit cells C and a portion of the plurality of separators 120 may be coupled to each other.

[0048] The wrapping film 200 may surround the stack 100 and be welded to the stack 100 to fix the plurality of unit cells C.

[0049] In one embodiment, welding may be performed by heat pressing.

[0050] In one embodiment, the wrapping film 200 may be made of a material including polyethylene terephthalate (PET) and ethylene vinyl acetate (EVA).

[0051] In one embodiment, the flexural rigidity of the wrapping film 200 may be greater than the flexural rigidity of the plurality of diaphragms 120 .

[0052] In addition, in order to solve the above problems, the present invention provides a method S500 for manufacturing an electrode assembly, which includes a stacking step S510 and a wrapping step S520.

[0053] In the stacking step S510 , a stack 100 may be formed.

[0054] In the wrapping step S520, the wrapping film 200 may surround one side and the other side of the stack 100 in the first direction and one side and the other side of the stack 100 in the third direction. In addition, the wrapping film 200 may be welded to at least one side or the other side of the stack 100 in the first direction.

[0055] In one embodiment, the wrapping film 200 may include a first wrapping film 210 and a second wrapping film 220 .

[0056] The wrapping step S520 may include a first wrapping step S522 and a second wrapping step S524.

[0057] In the first wrapping step S522 , the first wrapping film 210 may be welded to one side of the stack 100 in the first direction, at least a portion of one side of the stack 100 in the third direction, and at least a portion of the other side of the stack 100 in the third direction.

[0058] In the second wrapping step S524, after flipping the stack 100 to exchange one side and the other side of the stack 110 in the first direction, the second wrapping film 220 can be welded to one side of the stack 100 in the first direction and at least two ends of the first wrapping film 210 located on one side and the other side of the stack 100 in the third direction.

[0059] In one embodiment, the wrapping step S520 includes: after placing the wrapping film 200 on one side of the stack 100 in the first direction and pressing and fixing a predetermined area of ​​the wrapping film 200 placed on one side of the stack 100 in the first direction using a fixing member Z, moving the roller R in the third direction on one side of the stack 100 in the first direction to press and fuse the wrapping film 200 to the one side of the stack 100 in the first direction by hot pressing, and moving the roller R in the first direction on one side and the other side of the stack 100 in the third direction to press and fuse the wrapping film 200 to at least a portion of the one side of the stack 100 in the third direction and at least a portion of the other side of the stack 100 in the third direction by hot pressing.

[0060] In one embodiment, the wrapping step S520 includes: after placing the wrapping film 200 on one side of the stack 100 in the first direction and pressing and fixing a predetermined area of ​​the wrapping film 200 placed on one side of the stack 100 in the first direction using a fixing member Z, moving the roller R in the first direction on one side and the other side of the stack 100 in the third direction to press and weld the wrapping film 200 to the wrapping film 200 that has been welded to one side and the other side of the stack 100 in the third direction by hot pressing.

[0061] In one embodiment, in the wrapping step S520 , the wrapping film 200 may be heated to a first temperature and welded to the stack 100 .

[0062] The first temperature may be higher than a second temperature to which one or more of the plurality of membranes 120 may be heated to be bonded to one or more of the plurality of electrodes 110 .

[0063] In one embodiment, the first temperature may be equal to or higher than 110 degrees Celsius and lower than 160 degrees Celsius.

[0064] The second temperature may be equal to or higher than 80 degrees Celsius and lower than 110 degrees Celsius.

[0065] Beneficial effects

[0066] According to an embodiment of the present invention, the electrode assembly 10 may include: a stack 100, which is formed by aligning a plurality of electrodes 110 and a plurality of separators 120 in a first direction and stacking them alternately; and a wrapping film 200, which surrounds the stack 100 and can be welded to the stack 100 to fix the plurality of electrodes 110 and the plurality of separators 120.

[0067] Therefore, since the wrap film 200 surrounds and is welded to the stack 100, the aligned electrodes 110 and the separator 120 can be firmly fixed and protected. Therefore, deformation and damage of the separator 120, destruction of the alignment of the stack 100, and short circuit caused thereby can be prevented. In particular, even when an expansion phenomenon occurs in which the electrode 110 expands after being wetted by the electrolyte, the wrap film 200 can fix and protect the stack 100 without falling off from the stack 100, thereby preventing deformation and damage of the separator 120, and preventing destruction of the alignment of the stack 100 and short circuit caused thereby.

[0068] Furthermore, since the aligned electrodes 110 and separators 120 can be firmly fixed by the wrapping film 200, the stack 100 can be prevented from bending when transporting the electrode assembly 10. Therefore, deformation and damage of the separator 120 and disruption of alignment of the stack 100 can be prevented.

[0069] According to an embodiment of the present invention, the electrode tabs 112 of the plurality of electrodes 110 may be disposed on one side or the other side of the stack 100 in the second direction intersecting the first direction. The wrapping film 200 may surround one side and the other side of the stack 100 in the first direction and one side and the other side of the stack 100 in a third direction intersecting the first direction and the second direction, and may be fused to at least one side or the other side of the stack 100 in the first direction.

[0070] Therefore, the wrapping film 200 can conveniently surround the stack 100 while avoiding the electrode tab 112 of the electrode 110, and the wrapping film 200 can conveniently be welded to the stack 100. Therefore, the manufacture of the electrode assembly 10 can be facilitated, and the manufacturing cost of the electrode assembly 10 can be reduced.

[0071] According to an embodiment of the present invention, the wrapping film 200 may be welded to one or the other side of the stack 100 in the first direction and one or the other side of the stack 100 in the third direction.

[0072] Therefore, since the area of ​​the wrap film 200 welded to the stack 100 or the number of separators 120 to which the wrap film 200 is welded increases, the aligned electrodes 110 and separators 120 can be more firmly fixed. Therefore, deformation and damage of the separator 120, destruction of the alignment of the stack 100, and short circuits caused thereby can be prevented.

[0073] According to an embodiment of the present invention, the wrapping film 200 may include a first wrapping film 210 and a second wrapping film 220. The first wrapping film 210 may be bent to surround one side of the stack 100 in the first direction, at least a portion of one side of the stack 100 in the third direction, and at least a portion of the other side of the stack 100 in the third direction, and may be fused to at least one side of the stack 100 in the first direction. The second wrapping film 220 may be bent to surround the other side of the stack 100 in the first direction, at least a portion of one side of the stack 100 in the third direction, and at least a portion of the other side of the stack 100 in the third direction, and have two ends overlapping with two ends of the first wrapping film 210 on one side and the other side of the stack 100 in the third direction in the first direction, and may be fused to the other side of the stack 100 in the first direction and at least two overlapping ends of the first wrapping film 210.

[0074] Therefore, by surrounding the stack 100 with the two wrapping films 210 and 220 and welding the two wrapping films 200 to the stack 100 , it is possible to facilitate manufacturing the electrode assembly 10 having a simple configuration at low cost.

[0075] According to an embodiment of the present invention, the first wrapping film 210 may be welded to one side of the stack 100 in the first direction, at least a portion of one side of the stack 100 in the third direction, and at least a portion of the other side of the stack 100 in the third direction.

[0076] Therefore, since the area of ​​the wrap film 200 welded to the stack 100 or the number of separators 120 to which the wrap film 200 is welded increases, the aligned electrodes 110 and separators 120 can be more firmly fixed. Therefore, deformation and damage of the separator 120, destruction of the alignment of the stack 100, and short circuits caused thereby can be prevented.

[0077] According to an embodiment of the present invention, each of the plurality of separators 120 may extend in one direction and the other direction of the third direction further than the plurality of electrodes 110 adjacent to each of the plurality of separators 120. When the wrap film 200 is welded to the stack 100, one end and the other end of at least a portion of the plurality of separators 120 in the third direction may be bent to be close to or in contact with one end and the other end of the plurality of adjacent separators 120 in the third direction.

[0078] Therefore, since the wrap film 200 surrounds the stack 100 while pressing the diaphragm 120, the aligned electrodes 110 and the diaphragm 120 can be fixed more firmly. In addition, since the one end and the other end of the diaphragm 120 in the third direction can be fixed in a bent state by fixing the central part, one end and the other end of the diaphragm 120 in the second direction, the pressure applied to the one side and the other side of the stack 100 in the third direction can be easily absorbed. Since the one end and the other end of the diaphragm 120 are placed close to the one end and the other end of the adjacent diaphragm 120 in the third direction, the strength of the one side and the other side of the stack 100 in the third direction can be increased. Therefore, the stack 100 and the diaphragm 120 can be protected. Therefore, the deformation and damage of the diaphragm 120, the destruction of the alignment of the stack 100, and the short circuit caused thereby can be prevented. In particular, even when an expansion phenomenon occurs in which the electrode 110 expands after being wetted by the electrolyte, the wrapping film 200 can fix and protect the stack 100 without falling off the stack 100, thereby preventing the separator 120 from being deformed and damaged, and preventing the alignment of the stack 100 from being destroyed and the resulting short circuit. In addition, when the electrode assembly 10 is transported, the stack 100 can be prevented from being bent. Therefore, the deformation and damage of the separator 120 and the destruction of the alignment of the stack 100 can be prevented.

[0079] In addition, even when the alignment of the stack 100 is broken, the electrode 110 (e.g., a pair of electrodes disposed on one side and the other side of the separator in the first direction) is blocked by one or the other bent end of the separator 120 in the third direction, thereby greatly reducing the possibility of direct electrical connection between the electrode 110 and the battery case. Therefore, a short circuit can be prevented.

[0080] According to an embodiment of the present invention, each of the plurality of separators 120 may extend in one direction and the other direction of the third direction further than the plurality of electrodes 110 adjacent to each of the plurality of separators 120. When the wrapping film 200 is welded to the stack 100, one end or the other end in the third direction of each of two or more of the plurality of separators 120 stacked continuously in the first direction may be bent together in one direction or the other direction of the first direction, wherein one or more of the plurality of electrodes 110 are located between the plurality of separators.

[0081] Therefore, since the wrap film 200 surrounds the stack 100 while pressing the continuously stacked separators 120 in a similar direction, the aligned electrodes 110 and separators 120 are more firmly fixed. In addition, since one end or the other end of the continuously stacked separators 120 in the third direction can be concentrated in the third direction, the strength of one side and the other side of the stack 100 in the third direction is increased. Therefore, the stack 100 and the separator 120 can be protected. Therefore, deformation and damage of the separator 120, destruction of the alignment of the stack 100, and short circuits caused thereby can be prevented.

[0082] According to an embodiment of the present invention, the wrapping film 200 may extend in the second direction to surround an area corresponding to a predetermined section S in the second direction of each of the plurality of diaphragms 120. The predetermined section S may be a section extending from the center of each of the plurality of diaphragms 120 in the second direction to one end and the other end of each of the plurality of diaphragms 120 in the second direction.

[0083] Therefore, the wrap film 200 can surround the entirety of the central portion, one end, and the other end in the second direction of each of the plurality of separators 120. Therefore, since the wrap film 200 can stably surround the stack 100, the aligned electrodes 110 and separators 120 can be more firmly fixed. Therefore, deformation and damage of the separator 120, destruction of the alignment of the stack 100, and short circuits caused thereby can be prevented.

[0084] According to an embodiment of the present invention, the wrapping film 200 may be welded to one end or the other end of at least a portion of the plurality of diaphragms 120 in the third direction by a length corresponding to the predetermined section S in the second direction.

[0085] Therefore, since the area of ​​the wrap film 200 welded to the stack 100 or the number of the separators 120 to which the wrap film 200 is welded increases, the aligned electrodes 110 and the separators 120 can be fixed more firmly. In addition, since the center portion, one end portion, and the entirety of the other end portion of the separator 120 in the second direction surrounded by the wrap film 200 are welded to the wrap film 200 in the second direction, the aligned electrodes 110 and the separators can be fixed more firmly. Therefore, deformation and damage of the separator 120, destruction of the alignment of the stack 100, and short circuits caused thereby can be prevented.

[0086] According to an embodiment of the present invention, when the wrapping film 200 is welded to the stack 100, at least a first portion P1 of a predetermined section S at one end in the third direction of each diaphragm of at least a portion of the multiple diaphragms 120 can be bent to be close to or contact each diaphragm of a plurality of adjacent diaphragms 120, and at least a second portion P2 of a predetermined section S at another end in the third direction of each diaphragm of at least a portion of the multiple diaphragms 120 can be bent to be close to or contact each diaphragm of a plurality of adjacent diaphragms 120.

[0087] Therefore, since the wrapping film 200 can surround the entirety of the central portion, one end, and the other end of each of the plurality of diaphragms 120 in the second direction by pressing and surrounding the plurality of diaphragms 120 with the wrapping film 200, the aligned electrodes 110 and diaphragms 120 can be more firmly fixed.

[0088] In addition, since one end and the other end of the diaphragm 120 in the third direction, more specifically, the central part, one end and the entirety of the other end of the diaphragm 120 in the third direction in the second direction are fixed while being bent along the second direction, the pressure applied to one side and the other side of the stack 100 in the third direction can be easily absorbed.

[0089] In addition, since one end and the other end of the diaphragm 120 in the third direction, more specifically, the central portion of one end or the other end of the diaphragm 120 in the second direction, one end and the other end are all placed close to one end and the other end of the adjacent diaphragm 120, the strength of one side and the other end of the diaphragm 120 in the third direction can be increased. Therefore, the diaphragm 120 can be protected, and deformation and damage of the diaphragm 120, damage to the alignment of the stack 100, and short circuit caused thereby can be prevented.

[0090] In addition, even when the alignment of the stack 100 is broken, the electrode 110 (e.g., a pair of electrodes disposed on one side and the other side of the separator in the first direction) is blocked by one or the other curved end of the separator 120 in the third direction, more specifically, by the central portion, one end, and the other end of one or the other curved end of the separator 120 in the third direction in the second direction, thereby greatly reducing the possibility of direct electrical connection between the electrode 110 and the battery case. Therefore, short circuits can be prevented.

[0091] Therefore, in order to insulate the outermost electrode 110 of the stack 100 in the first direction from the battery case (not shown), the separator 120 disposed at one end or the other end of the stack 100 in the first direction may be replaced with the wrapping film 200. Therefore, the thickness of the electrode assembly 10 may be reduced, thereby increasing the energy density of the secondary battery including the electrode assembly 10.

[0092] According to an embodiment of the present invention, the stack 100 includes a plurality of unit cells C aligned and stacked in a first direction. Each of the plurality of unit cells C may include a portion of the plurality of electrodes 110 and a portion of the plurality of separators 120 alternately stacked. A portion of the plurality of electrodes 110 and a portion of the plurality of separators 120 constituting each of the plurality of unit cells C may be bonded to each other. The wrapping film 200 surrounds the stack 100 and may be welded to the stack 100 to fix the plurality of unit cells C.

[0093] Therefore, since the electrode 110 and the separator 120 of each of the plurality of unit cells C constituting the stack 100 surrounded by the wrap film 200 and welded to the wrap film 200 are previously bonded to each other, the aligned electrode 110 and the separator 120 can be more firmly fixed and safely protected. Therefore, deformation and damage of the separator 120, destruction of the alignment of the stack 100, and short circuit caused thereby can be prevented.

[0094] According to an embodiment of the present invention, welding may be performed by heat pressing.

[0095] Therefore, the wrapping film 200 can be conveniently welded to the stack 100 with a simple configuration and at low cost.

[0096] According to an embodiment of the present invention, the wrapping film 200 may be made of a material including polyethylene terephthalate (PET) and ethylene vinyl acetate (EVA).

[0097] Therefore, not only the fixing strength and bonding strength of the wrapping film 200 will be excellent, but also the heat exchange performance of the wrapping film 200 will be excellent. Therefore, the aligned electrodes 110 and the separator 120 can be firmly fixed and safely protected, and although the stack 100 is surrounded by the wrapping film 200, the stack 100 will not be overheated, so that the performance of the secondary battery will not deteriorate and its life will not be shortened. In addition, since the wrapping film 200 has excellent insulation properties, the outermost separator 120 of the stack 100 can be omitted, thereby reducing the thickness of the electrode assembly 10. In addition, since a commercially available inexpensive film can be used as the wrapping film 200, the electrode assembly 10 can be conveniently manufactured and the manufacturing cost of the electrode assembly 10 can be reduced.

[0098] According to an embodiment of the present invention, the bending rigidity of the wrapping film 200 may be greater than the bending rigidity of the plurality of diaphragms 120 .

[0099] Therefore, the wrapping film 200 may firmly and directly fix the aligned electrodes 110 and the separator 120 .

[0100] According to an embodiment of the present invention, a manufacturing method S500 of an electrode assembly includes: a stacking step S510, the stacking step forms a stack 100; and a wrapping step S520, the wrapping step surrounds one side and the other side of the stack 100 in a first direction and one side and the other side of the stack 100 in a third direction with a wrapping film 200, and welds the wrapping film 200 to at least one side or the other side of the stack 100 in the first direction.

[0101] Therefore, the electrode assembly 10 can be manufactured in which the aligned electrodes 110 and the separator 120 can be firmly fixed and protected. Therefore, deformation and damage of the separator 120, destruction of the alignment of the stack 100, and short circuit caused thereby can be prevented.

[0102] According to an embodiment of the present invention, the wrapping film 200 may include a first wrapping film 210 and a second wrapping film 220. The wrapping step S520 may include: a first wrapping step S522 of welding the first wrapping film 210 to one side of the stack 100 in the first direction, at least a portion of one side of the stack 100 in the third direction, and at least a portion of the other side of the stack 100 in the third direction; and a second wrapping step S524 of welding the second wrapping film 220 to one side of the stack 100 in the first direction and at least two ends of the first wrapping film 210 located on one side and the other side of the stack 100 in the third direction after flipping the stack 100 to interchange the one side and the other side of the stack in the first direction.

[0103] Therefore, the stack 100 may be surrounded by two wrapping films 210 and 220 and welded to the stack 100. Here, in addition to the step (f) of turning over the stack 100, the first wrapping step S522 ( Fig. 9 (a) to (e)) and the second wrapping step S524 ( Fig. 9 (f) to (k)) in the figure may correspond to each other. Therefore, since the manufacturing process of the electrode assembly 10 is simplified, the manufacturing equipment for the electrode assembly 10 may be simplified and the manufacturing cost of the electrode assembly 10 may be reduced.

[0104] According to an embodiment of the present invention, in the wrapping step S520, after the wrapping film 200 is placed on one side of the stack 100 in the first direction and a predetermined area of ​​the wrapping film 200 placed on one side of the stack 100 in the first direction is pressed and fixed by the fixing member Z, the roller R can be moved in the third direction on one side of the stack 100 in the first direction to press and fuse the wrapping film 200 to the one side of the stack 100 in the first direction by hot pressing, and the roller R can be moved in the first direction on one side and the other side of the stack 100 in the third direction to press and fuse the wrapping film 200 to at least a portion of one side of the stack 100 in the third direction and at least a portion of the other side of the stack 100 in the third direction by hot pressing.

[0105] Therefore, the wrapping film 200 can be welded to the one side of the stack 100 in the first direction and the one side and the other side of the stack 100 in the third direction simply by fixing the wrapping film 200 on the one side of the stack 100 in the first direction with the fixing member Z. Therefore, when the wrapping film 200 is welded to the stack 100, the alignment of the stack 100 in the first direction can be easily maintained, and the wrapping film 200 can be welded to each of the one side of the stack 100 in the first direction and the one side and the other side of the stack 100 in the third direction with minimal fixing. Therefore, since the manufacturing process of the electrode assembly 10 is simplified, the manufacturing equipment for the electrode assembly 10 can be simplified and the manufacturing cost of the electrode assembly 10 can be reduced.

[0106] In addition, since the wrap film 200 is welded to one side and the other side of the stack 100 in the third direction by pressing the wrap film 200 while moving the roller R in the first direction, when the wrap film 200 is welded, one end and the other end of the separator 120 in the third direction are naturally bent to be close to or contact one end and the other end in the third direction of the adjacent separator 120. Therefore, deformation and damage of the separator 120, destruction of alignment of the stack 100, and short circuit caused thereby can be prevented.

[0107] According to an embodiment of the present invention, in the wrapping step S520, after the wrapping film 200 is placed on one side of the stack 100 in the first direction and a predetermined area of ​​the wrapping film 200 placed on one side of the stack 100 in the first direction is pressed and fixed by a fixing member Z, the roller R can be moved in the first direction on one side and the other side of the stack 100 in the third direction to press and fuse the wrapping film 200 to the wrapping film 200 that has been fused to the one side and the other side of the stack 100 in the third direction by hot pressing.

[0108] Therefore, the stack 100 may be securely and conveniently surrounded by the wrapping film 200 .

[0109] According to an embodiment of the present invention, in the wrapping step S520, the wrapping film 200 may be heated to a first temperature and welded to the stack 100. The first temperature may be higher than a second temperature, and one or more of the plurality of separators 120 are heated to the second temperature to be bonded to one or more of the plurality of electrodes 110.

[0110] Therefore, when the wrap film 200 is welded to the separator 120 of the stack 100, the separator 120 may also be welded to the wrap film 200 and / or the electrode 110, resulting in a strong bond between the wrap film 200 and the stack 100. Therefore, the wrap film 200 can fix and protect the stack 100 from falling off the stack 100, thereby preventing the separator 120 from being deformed and damaged, and preventing the alignment of the stack 100 from being disrupted and the resulting short circuit.

[0111] According to an embodiment of the present invention, the first temperature may be equal to or higher than 110 degrees Celsius and lower than 160 degrees Celsius. The second temperature may be equal to or higher than 80 degrees Celsius and lower than 110 degrees Celsius.

[0112] Therefore, the wrapping film 200 can fix and protect the stack 100 from falling off the stack 100, thereby preventing the separator 120 from being deformed and damaged, and preventing the destruction of the alignment of the stack 100 and the resulting short circuit.

[0113] In addition to the above-described effects, specific effects of the present invention will be described together with the following detailed description of implementing the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0114] Figure 1 and Figure 2 1 and 2 are a perspective view and a front view, respectively, showing a stack of electrodes and a separator according to an embodiment of the present invention.

[0115] Figure 3 is a perspective view showing a conventional electrode assembly, wherein a tape is attached to Figure 1 and Figure 2 of stacked pieces.

[0116] Figure 4 and Figure 5 1 and 2 are respectively a perspective view and a front view showing an electrode assembly according to an embodiment of the present invention, in which a wrapping film is welded to Figure 1 and Figure 2 of stacked pieces.

[0117] Figure 6 It is shown Figure 4 and Figure 5 A three-dimensional view of a diaphragm of an electrode assembly.

[0118] Figure 7 is a front view showing an electrode assembly according to another embodiment of the present invention.

[0119] Figure 8 is a flowchart illustrating a method of manufacturing an electrode assembly according to an embodiment of the present invention.

[0120] Fig. 9 The order is shown Figure 4 and Figure 5 FIG. 1 is a diagram of a method for manufacturing an electrode assembly.

[0121] [Explanation of Reference Numerals]

[0122] 10: Electrode assembly

[0123] 100: stacked part 110: electrode

[0124] 112: Electrode connector 120: Diaphragm

[0125] 200: Wrapping film

[0126] 210: first wrapping film 220: second wrapping film

[0127] C: Cell DETAILED DESCRIPTION

[0128] The above-mentioned objects, features and advantages will be described in detail below with reference to the accompanying drawings, so that those skilled in the art to which the present invention belongs will be able to easily implement the technical concept of the present invention. When describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals are used to indicate the same or similar parts.

[0129] Although "first", "second", etc. can be used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from another component, and of course, unless otherwise specified, the first component may be the second component.

[0130] Throughout the specification, unless otherwise specified, each component may be singular or plural.

[0131] Hereinafter, an arbitrary component is arranged on the "upper portion (or lower portion)" or "upper portion (or lower portion)" of a component means that the arbitrary component is placed in contact with the upper (or lower) surface of the component. In addition, this may mean that other components may be inserted between the component and the arbitrary component arranged on (or below) the component.

[0132] In addition, when one component is described as being “linked,” “coupled” or “connected” to another component, the components may be directly connected or connected to each other, but other components may be “interposed” between the components, or each component may be “linked,” “coupled” or “connected” through other components.

[0133] Unless the context clearly dictates otherwise, singular expressions used herein include plural expressions. In the present application, terms such as "consisting of" or "comprising" should not be interpreted as necessarily including all the various components or steps described in the specification. This should be interpreted as it may not include a part of the components or a part of the steps. Or it may also include additional components or steps.

[0134] Figure 1 and Figure 2 1 and 2 are a perspective view and a front view, respectively, showing a stack of electrodes and a separator according to an embodiment of the present invention. Figure 3 is a perspective view showing a conventional electrode assembly in which a tape is attached to Figure 1 and Figure 2 of stacked pieces. Figure 4 and Figure 5 1 and 2 are respectively a perspective view and a front view showing an electrode assembly according to an embodiment of the present invention, in which a wrapping film is welded to Figure 1 and Figure 2 of stacked pieces. Figure 6 It is shown Figure 4 and Figure 5 A three-dimensional view of a diaphragm of an electrode assembly. Figure 7 is a front view showing an electrode assembly according to another embodiment of the present invention. Figure 8 is a flowchart illustrating a method of manufacturing an electrode assembly according to an embodiment of the present invention. Fig. 9 The order is shown Figure 4 and Figure 5 FIG. 1 is a diagram of a method for manufacturing an electrode assembly.

[0135] [Conventional electrode assembly]

[0136] refer to Figures 1 to 3 , a conventional electrode assembly may include a stack 100 and a tape T ( Figure 3 ). A secondary battery (not shown) may be formed by housing the electrode assembly in a battery case, injecting an electrolyte into the battery case, and sealing the battery case. Hereinafter, the stack 100 and the tape T will be described.

[0137] The stack 100 may include a plurality of electrodes 110 and a plurality of separators 120 .

[0138] The stack 100 may be formed by alternately stacking a plurality of electrodes 110 and a plurality of separators 120 in a first direction. That is, the plurality of electrodes 110 and the plurality of separators 120 constituting the stack 100 may be alternately stacked in a first direction (e.g., an upward direction and a downward direction). In addition, the stack 100 may be formed by aligning and alternately stacking a plurality of electrodes 110 and a plurality of separators 120 in a first direction. That is, the plurality of electrodes 110 and the plurality of separators 120 constituting the stack 100 may be aligned and stacked.

[0139] In addition, the stack 100 may include a plurality of unit cells C. The plurality of unit cells C constituting the stack 100 may be aligned and stacked in the first direction. The plurality of unit cells C may be of two types (eg, a single cell C1 and a half cell C2). Figure 2 )).

[0140] Each of the plurality of unit cells C may include a portion of the plurality of electrodes 110 and a portion of the plurality of separators 120 that are alternately stacked ( Figure 2 ). For example, the single cell C1 may be a unit cell C in which the separator 120, the electrode 110 (e.g., the positive electrode), the separator 120 and the electrode 110 (e.g., the negative electrode) are stacked in sequence, and the half cell C2 may be a unit cell C in which the separator 120, the electrode 110 (e.g., the positive electrode) and the separator 120 are stacked in sequence.

[0141] The electrode 110 and the separator 120 constituting each unit cell C may be combined with each other.

[0142] An example of a method for manufacturing the single cell C1 according to the prior art is as follows.

[0143] While the lower electrode 110 is moved by a conveyor belt or the like, the upper separator 120 and the lower separator 120 are stacked on the upper surface and the lower surface (one side surface and the other side surface in the first direction) of the lower electrode 110, respectively, after which the upper electrode 110 is further stacked on top. A lamination process is then performed in which heat and pressure are applied to the plurality of stacked electrodes 110 and the plurality of stacked separators 120. By performing the lamination process, the electrode 110 and the separator 120 may be bonded to each other to form a solid single cell C1.

[0144] The manufacturing method of the single cell C1 can be similarly applied to the manufacturing method of the half cell C2.

[0145] For example, the half cell C2 may be stacked on one side of the single cell C1 in the first direction in such a manner that the electrode 110 at one end (e.g., the upper end) of the single cell C1 in the first direction is not in direct contact with the battery case (not shown). Since a plurality of separators 120 are stacked on both one end and the other end of the half cell C2 in the first direction, the half cell C2 may be insulated from the battery case.

[0146] The tape T may be attached to the stack 100. Here, the tape T may be attached while surrounding the stack 100. The tape T may fix the stack 100 in alignment.

[0147] However, when the tape T is attached, the separator 120 is partially bent by the tape T, causing the separator 120 or the electrode 110 to be damaged or short-circuited. In addition, during the electrolyte injection process or the degassing process, the tape T may be easily separated from the stack 100, causing the separator 120 to be deformed and short-circuited.

[0148] Therefore, novel methods are needed to secure the aligned stack 100 .

[0149] [Electrode assembly according to an embodiment of the present invention]

[0150] refer to Figure 4 and Figure 5 , the electrode assembly 10 according to an embodiment of the present invention may include a stack 100 and a wrap film 200. As described above, when the electrode assembly 10 is accommodated in a battery case (not shown) and the battery case is sealed after the electrolyte is injected into the battery case, a secondary battery (not shown) may be formed. Hereinafter, the stack 100 and the wrap film 200 will be described.

[0151] The stack 100 is as described above ( Figure 1 and Figure 2 ).

[0152] The wrap film 200 may surround the stack 100. The wrap film 200 may be welded to the stack 100 to fix the plurality of electrodes 110 and the plurality of separators 120 constituting the stack 100. Specifically, the wrap film 200 may fix the plurality of electrodes 110 and the plurality of separators 120 aligned.

[0153] Here, welding may refer to melting a substrate (wrapping film) and bonding it to an object (stack or membrane).

[0154] Therefore, when the wrap film 200 surrounds and is welded to the stack 100, the aligned electrodes 110 and the separator 120 can be firmly fixed and protected. Therefore, deformation and damage of the separator 120, destruction of the alignment of the stack 100, and short circuit caused thereby can be prevented. In particular, even when an expansion phenomenon occurs in which the electrode 110 expands after the electrolyte is wetted, the wrap film 200 can fix and protect the stack 100 without falling off from the stack 100, thereby preventing deformation and damage of the separator 120, and preventing destruction of the alignment of the stack 100 and short circuit caused thereby.

[0155] Furthermore, since the aligned electrodes 110 and separators 120 can be firmly fixed by the wrapping film 200, the stack 100 can be prevented from bending when transporting the electrode assembly 10. Therefore, deformation and damage of the separator 120 and disruption of alignment of the stack 100 can be prevented.

[0156] The welding may be performed by a heat press method, an ultrasonic method, etc. Among these methods, the wrapping film 200 may be welded to the stack 100 by the heat press method.

[0157] Therefore, the wrapping film 200 can be conveniently welded to the stack 100 with a simple configuration and at low cost.

[0158] The wrap film 200 can be made of a material comprising polyethylene terephthalate (PET) and ethylene vinyl acetate (EVA). For example, the wrap film 200 can be a double-layer film in which an ethylene vinyl acetate (EVA) layer is laminated on a polyethylene terephthalate (PET) layer. Such a double-layer film can be formed by hot pressing ethylene vinyl acetate (EVA) or melt coating ethylene vinyl acetate (EVA) resin on a polyethylene terephthalate (PET) film. Such a double-layer film is widely used in coatings, printed materials or labels.

[0159] Therefore, not only the fixing strength and bonding strength of the wrapping film 200 can be excellent, but also the heat exchange performance of the wrapping film 200 can be excellent. Therefore, the aligned electrodes 110 and the separator 120 can be firmly fixed and safely protected, and although the stack 100 is surrounded by the wrapping film 200, the stack 100 will not overheat, so that the performance of the secondary battery will not deteriorate and its life will not be shortened. In addition, since the wrapping film 200 has excellent insulation properties, the outermost separator 120 of the stack 100 can be omitted, thereby reducing the thickness of the electrode assembly 10. In addition, since a commercially available inexpensive film can be used as the wrapping film 200, the electrode assembly 10 can be conveniently manufactured and the manufacturing cost of the electrode assembly 10 can be reduced.

[0160] The wrapping film 200 may have greater bending rigidity than the separator 120. For example, the wrapping film 200 made of a material including polyethylene terephthalate (PET) and ethylene vinyl acetate (EVA) has greater bending rigidity than the separator 120 made of polyethylene (PE) at the same thickness.

[0161] Therefore, the wrapping film 200 may firmly and directly fix the aligned electrodes 110 and the separator 120 .

[0162] In addition, the wrapping film 200 made of a material including polyethylene terephthalate (PET) and ethylene vinyl acetate (EVA) may be less expensive than the separator 120 made of a polyethylene (PE) material. Unlike the wrapping film 200, the separator 120 may not be made of a material including polyethylene terephthalate (PET) and ethylene vinyl acetate (EVA).

[0163] The electrode contact 112 of each electrode in the plurality of electrodes 110 is on one side (e.g., the front side) or the other side (e.g., the rear side) of the stack 100 in a second direction (e.g., the front direction and the rear direction) intersecting with the first direction (e.g., the upward direction and the downward direction). Here, the wrapping film 200 may surround: one side (e.g., the upper side) and the other side (e.g., the lower side) of the stack 100 in the first direction; and one side (e.g., the left side) and the other side (e.g., the right side) of the stack 100 in a third direction (e.g., the left direction and the right direction) intersecting with the first direction and the second direction. In addition, the wrapping film 200 may be fused to at least one side and / or the other side of the stack 100 in the first direction.

[0164] Therefore, the stack 100 can be easily surrounded by the wrapping film 200 to avoid the electrode tab 112 of the electrode 110, and can be conveniently welded to the stack 100. Therefore, the electrode assembly 10 can be conveniently manufactured, and the manufacturing cost of the electrode assembly 10 can be reduced.

[0165] The wrapping film 200 may be welded to: one side and / or the other side of the stack 100 in the first direction; and one side and / or the other side of the stack 100 in the third direction. For example, the wrapping film 200 may be welded to: the upper surface of the diaphragm 120 disposed on the top side (upper end) of the stack 100 in the first direction (upward direction and downward direction); and the lower surface of the diaphragm 120 disposed on the bottom side (lower end) of the stack 100 in the first direction.

[0166] Therefore, since the area of ​​the wrap film 200 welded to the stack 100 or the number of separators 120 to which the wrap film 200 is welded increases, the aligned electrodes 110 and separators 120 can be more firmly fixed. Therefore, deformation and damage of the separator 120, destruction of the alignment of the stack 100, and short circuits caused thereby can be prevented.

[0167] In addition, as shown in the figure, when one end (left part) and the other end (right part) of the diaphragm 120 arranged at one end (upper end) of the stack 100 in the first direction are bent toward the other end (downward) in the first direction, the central part of the diaphragm 120 arranged at one end (upper end) of the stack 100 can constitute one side (upper side) of the stack 100 in the first direction, and one end (left part) and the other end (right part) of the diaphragm 120 arranged at one end (upper end) of the stack 100 can constitute one side (left side) and the other side (right side) of the stack 100 in the third direction.

[0168] Further references Figure 6 The wrapping film 200 may extend in the second direction to surround a predetermined section S ( Figure 6 The predetermined section S may be a section extending from the center of each of the plurality of diaphragms in the second direction to one end and the other end of each of the plurality of diaphragms 120 in the second direction.

[0169] For example, as shown in the figure, the predetermined section S extends from the center of the diaphragm 120 in the second direction to one end and the other end of the diaphragm 120 in the second direction to include the entire area of ​​the diaphragm 120 in the second direction. However, the present invention is not limited to this configuration. That is, as another example, unlike the drawings, the predetermined section S may extend from the center of the diaphragm 120 toward one end and the other end of the diaphragm 120 in the second direction to a point within the diaphragm 120 that is spaced a predetermined distance from one end and the other end of the diaphragm 120.

[0170] Therefore, the wrap film 200 can surround the entirety of the central portion, one end, and the other end in the second direction of each of the plurality of separators 120. Therefore, since the wrap film 200 can stably surround the stack 100, the aligned electrodes 110 and separators 120 can be more firmly fixed. Therefore, deformation and damage of the separator 120, destruction of the alignment of the stack 100, and short circuits caused thereby can be prevented.

[0171] The wrapping film 200 is welded to a portion P1 or P2 ( Figure 6) is welded to one end or the other end of at least a portion of the plurality of diaphragms 120 in the third direction.

[0172] Therefore, since the area to which the wrap film 200 is welded to the stack 100 or the number of separators 120 to which the wrap film 200 is welded increases, the aligned electrodes 110 and separators 120 can be fixed more firmly. In addition, since the entirety of the central portion, one end, and the other end of each of the plurality of separators 120 in the second direction is surrounded by the wrap film 200, the aligned electrodes 110 and separators 120 can be fixed more firmly. Therefore, deformation and damage of the separator 120, destruction of the alignment of the stack 100, and short circuits caused thereby can be prevented.

[0173] The wrapping film 200 may include a first wrapping film 210 and a second wrapping film 220 ( Figure 4 and Figure 5 ).

[0174] The first wrapping film 210 may be bent to surround: one side of the stack 100 in the first direction; at least a portion of one side of the stack 100 in the third direction; and at least a portion of the other side of the stack 100 in the third direction. The first wrapping film 210 may be welded to at least one side of the stack 100 in the first direction.

[0175] The second wrapping film 220 may be bent to surround: the other side of the stack 100 in the first direction; at least a portion of one side of the stack 100 in the third direction; and at least a portion of the other side of the stack 100 in the third direction. The second wrapping film 220 may have two ends that overlap with both ends of the first wrapping film 210 in the first direction on one side and the other side of the stack 100 in the third direction. The second wrapping film 220 may be welded to: the other side of the stack 100 in the first direction; and at least two overlapping ends of the first wrapping film 210.

[0176] Therefore, by surrounding the stack 100 with the two wrapping films 210 and 220 and welding the two wrapping films 210 , 220 to the stack 100 , the electrode assembly 10 having a simple configuration may be conveniently manufactured at low cost.

[0177] The first wrapping film 210 may be welded to one side of the stack 100 in the first direction, at least a portion of one side of the stack 100 in the third direction, and at least a portion of the other side of the stack 100 in the third direction.

[0178] For example, the first wrapping film 210 is bent to be welded to the diaphragm 120 provided at one end (top) of the stack 100 in the first direction (upward and downward directions), and in particular, to one side of the stack 100 in the first direction, at least a portion of one side of the stack 100 in the third direction, and at least a portion of the other side of the stack 100 in the third direction ( Figure 4 and Figure 5 ). In addition, the first wrapping film 210 may be welded to one end and the other end of the plurality of stacked separators 120 in the third direction, and in particular, to at least a portion of one side (left side) and at least a portion of the other side (right side) of the stack 100 in the third direction.

[0179] Therefore, since the area of ​​the wrap film 200 welded to the stack 100 or the number of separators 120 to which the wrap film 200 is welded increases, the aligned electrodes 110 and separators 120 can be more firmly fixed. Therefore, deformation and damage of the separator 120, destruction of the alignment of the stack 100, and short circuits caused thereby can be prevented.

[0180] Each of the plurality of diaphragms 120 may be shaped in the third direction ( Figure 1 and Figure 2 ) and extend further in one direction and another direction than the plurality of electrodes 110 adjacent to each of the plurality of diaphragms 120.

[0181] When the wrapping film 200 is welded to the stack 100 ( Figure 4 and Figure 5 ), one end and the other end of at least a portion of the plurality of diaphragms 120 in the third direction may be bent to be close to or in contact with one end and the other end of a plurality of adjacent diaphragms 120 in the third direction.

[0182] Therefore, since the wrap film 200 surrounds the stack 100 while pressing the diaphragm 120, the aligned electrodes 110 and the diaphragm 120 can be fixed more firmly. In addition, since one end and the other end of the diaphragm 120 in the third direction are fixed in a bent state, it is easy to absorb the pressure applied to one side and the other side of the stack 100 in the third direction. Since one end and the other end of the diaphragm 120 are placed close to one end and the other end of the adjacent diaphragm 120 in the third direction, the strength of one side and the other side of the stack 100 in the third direction can be increased. Therefore, the stack 100 and the diaphragm 120 can be protected. Therefore, deformation and damage of the diaphragm 120, destruction of the alignment of the stack 100, and short circuits caused thereby can be prevented. In particular, even when an expansion phenomenon occurs in which the electrode 110 expands after the electrolyte is wetted, the wrapping film 200 can fix and protect the stack 100 without falling off the stack 100, thereby preventing deformation and damage of the separator 120, and preventing the destruction of the alignment of the stack 100 and the resulting short circuit. In addition, when the electrode assembly 10 is transported, the stack 100 can be prevented from bending. Therefore, the deformation and damage of the separator 120 and the destruction of the alignment of the stack 100 can be prevented.

[0183] In addition, even when the alignment of the stack 100 is broken, the electrode 110 (e.g., a pair of electrodes disposed on one side and the other side of the separator in the first direction) is blocked by one or the other bent end of the separator 120 in the third direction, thereby greatly reducing the possibility of direct electrical connection between the electrode 110 and the battery case. Therefore, a short circuit can be prevented.

[0184] As described above, the wrapping film 200 may extend in the second direction to surround an area corresponding to the predetermined section S of each of the plurality of diaphragms 120. Here, as described above, the predetermined section S may be a section extending from the center of each of the plurality of diaphragms 120 in the second direction to one end and the other end of each diaphragm in the second direction.

[0185] In this case, when the wrapping film 200 is welded to the stack 100, a first portion P1 of the predetermined section S of one end of the diaphragm 120 in the third direction among the plurality of diaphragms 120 may be bent to be close to or in contact with an adjacent diaphragm 120, and a second portion P2 of the predetermined section S of the other end of the diaphragm 120 in the third direction among the plurality of diaphragms 120 may be bent to be close to or in contact with an adjacent diaphragm 120 ( Figure 4 , Figure 5 and Figure 6 ).

[0186] Therefore, since the wrap film 200 surrounds the stack 100 while pressing the diaphragm 120 by surrounding the center portion, one end, and the entirety of the other end of the diaphragm 120 in the second direction, the aligned electrode 110 and the diaphragm 120 can be fixed more firmly. In addition, since the one end and the other end of the diaphragm 120 in the third direction are fixed in a bent state by fixing the one end and the other end of the diaphragm 120 in the third direction in the center portion, one end, and the entirety of the other end, it is possible to conveniently absorb the pressure applied to the one side and the other side of the stack 100 in the third direction. In addition, since the one end and the other end of the diaphragm 120 in the third direction are placed close to the one end and the other end of the adjacent diaphragm 120 in the third direction by placing the one end and the other end of the diaphragm 120 in the third direction in the center portion, one end, and the entirety of the other end close to the one end and the other end of the adjacent diaphragm 120 in the third direction, the strength of the one side and the other side in the third direction can be increased. Therefore, the diaphragm 120 can be protected. Therefore, deformation and damage of the diaphragm 120 , disruption of alignment of the stack 100 , and short circuit caused thereby can be prevented.

[0187] Furthermore, even when the alignment of the stack 100 is disrupted, the electrode 110 (e.g., a pair of electrodes disposed on one side and the other side of the separator in the first direction) is blocked by one or the other curved end of the separator 120 in the third direction, more specifically, by the central portion, one end, and the other end of one or the other curved end of the separator 120 in the third direction, thereby greatly reducing the possibility of direct electrical connection between the electrode 110 and the battery case. Therefore, a short circuit can be prevented.

[0188] When the wrap film 200 is welded to the stack 100 , all of one end or all of the other end of each of the plurality of separators 120 stacked continuously in the first direction with the electrodes 110 therebetween are bent in one direction or the other direction of the first direction.

[0189] For example, Figure 5 As shown, all of one end and the other end of each of the seven separators 120 (with the electrodes 110 located therebetween) stacked continuously in the first direction are bent in the other direction (downward) of the first direction.

[0190] Therefore, since the wrap film 200 surrounds the stack 100 while pressing the continuously stacked separators 120 in a similar direction, the aligned electrodes 110 and separators 120 are more firmly fixed. In addition, since one end or the other end of the continuously stacked separators 120 in the third direction can be concentrated in the third direction, the strength of one side and the other side of the stack 100 in the third direction is increased. Therefore, the stack 100 and the separator 120 can be protected. Therefore, deformation and damage of the separator 120, destruction of the alignment of the stack 100, and short circuits caused thereby can be prevented.

[0191] In addition, the stack 100 may include a plurality of unit cells C ( Figure 2 , Figure 5 and Figure 7 ). Each of the plurality of unit cells C may include a portion of the plurality of electrodes 110 and a portion of the plurality of separators 120 that are alternately stacked constituting the stack 100. A portion of the plurality of electrodes 110 and a portion of the plurality of separators 120 constituting each of the plurality of unit cells C may be combined with each other. Specific details about the plurality of unit cells C are as described above.

[0192] The wrapping film 200 may surround and be fused to the stack 100 to fix the plurality of unit cells C.

[0193] Therefore, since the electrode 110 and the separator 120 of each of the plurality of unit cells C constituting the stack 100 surrounded by the wrap film 200 and welded to the wrap film 200 are previously bonded to each other, the aligned electrode 110 and the separator 120 can be more firmly fixed and safely protected. Therefore, deformation and damage of the separator 120, destruction of the alignment of the stack 100, and short circuit caused thereby can be prevented.

[0194] [Electrode assembly according to another embodiment of the present invention]

[0195] Reference Figure 7 According to another embodiment of the present invention, the electrode 110 may be located at one end or the other end of the stack 100 in the first direction of the electrode assembly.

[0196] For example, with Figure 5 Differently, the electrode 110 (rather than the separator 120) may be disposed at the top of the stack 100. Figure 7 Taking the unit cell C as a reference, Figure 5Differently, a modified cell C3 in which a separator 120 and an electrode 110 (eg, a positive electrode) are sequentially stacked may be provided instead of the half cell C2. That is, the separator 120 located at one end or the other end of the stack 100 in the first direction may be omitted.

[0197] The wrapping film 200 may be welded to one side surface or the other side surface in the first direction of each of the plurality of electrodes 110 located at one end or the other end of the stack 100 in the first direction.

[0198] Therefore, in order to insulate the outermost electrode 110 of the stack 100 in the first direction from the battery case (not shown), the separator 120 disposed at one end or the other end of the stack 100 in the first direction may be replaced with the wrapping film 200. Therefore, the thickness of the electrode assembly 10 may be reduced, thereby increasing the energy density of the secondary battery including the electrode assembly 10.

[0199] [Method for manufacturing electrode assembly]

[0200] refer to Fig. 9 , the manufacturing method S500 of the electrode assembly according to the embodiment may include a stacking step S510 and a wrapping step S520.

[0201] In the stacking step S510, the stack 100 may be formed. For example, the plurality of electrodes 110 and the plurality of separators 120 may be alternately stacked in the first direction. Here, the plurality of electrodes 110 and the plurality of separators 120 may be stacked in an aligned manner.

[0202] Specifically, for example, a plurality of unit cells C in which electrodes 110 and separators 120 are alternately stacked in a first direction may be aligned and stacked. Here, as described above, the electrodes 110 and separators 120 constituting each of the plurality of unit cells C may be previously bonded to each other. Figure 8 , in the wrapping step S520( Fig. 9 In (a) to (k)), the wrapping film 200 may surround and be fused to the stack 100. Specifically, the wrapping film 200 may surround one side and the other side of the stack 100 in the first direction and one side and the other side of the stack 100 in the third direction, and the wrapping film 200 is at least fused to one side and the other side of the stack 100 in the first direction.

[0203] Therefore, the electrode assembly 10 can be manufactured in which the aligned electrodes 110 and the separator 120 can be firmly fixed and protected. Therefore, deformation and damage of the separator 120, destruction of the alignment of the stack 100, and short circuit caused thereby can be prevented.

[0204] As described above, the wrapping film 200 may include a first wrapping film 210 and a second wrapping film 220 .

[0205] The wrapping step S520 may include a first wrapping step S522 ( Fig. 9 (a) to (e)) and the second wrapping step S524 ( Fig. 9 (f) to (k) in the figure.

[0206] In the first wrapping step S522 ( Fig. 9 In (a) to (e)), the first wrapping film 210 can be welded to one side of the stack 100 in the first direction, at least a portion of one side of the stack 100 in the third direction, and at least a portion of the other side of the stack 100 in the third direction.

[0207] Specifically, for example, Fig. 9 As shown in (a), (b) and (d) of FIG. 1 , the first wrapping film 210 may be placed on one side of the stack 100 in the first direction and then welded to the one side of the stack 100 in the first direction. Fig. 9 As shown in (c), the first wrapping film 210 may be placed on one side of the stack 100 in the third direction and then welded to the one side of the stack 100 in the third direction. Fig. 9 As shown in (e), the first wrapping film 210 may be placed on the other side of the stack 100 in the third direction and then welded to the other side of the stack 100 in the third direction.

[0208] In the second wrapping step S524 ( Fig. 9 In (f) to (k)), if Fig. 9 As shown in (f), after flipping the stack 100 to interchange one side and the other side of the stack in the first direction, the second wrapping film 220 can be welded to one side of the stack 100 in the first direction and at least two ends of the first wrapping film 210 located on one side and the other side of the stack 100 in the third direction.

[0209] Specifically, for example, Fig. 9 As shown in (g), (h) and (j) of FIG. 1 , the second wrapping film 220 may be placed on one side of the stack 100 in the first direction (the other side of the stack 100 in the first direction before the stack 100 is turned over) and welded to the one side of the stack 100 in the first direction. Fig. 9As shown in (i), the second wrapping film 220 may be placed on one side of the stack 100 in the third direction in such a manner that the end of the first wrapping film 210 overlaps the second wrapping film 220 in the first direction, and then may be welded to the first wrapping film 210. Here, the second wrapping film 220 may be welded to a portion of the one side of the stack 100 in the third direction to which the first wrapping film 210 is not welded. In addition, as Fig. 9 As shown in (k), the second wrapping film 220 may be placed on the other side of the stack 100 in the third direction in such a manner that the end of the first wrapping film 210 overlaps the second wrapping film 220 in the first direction, and then may be welded to the first wrapping film 210. Here, the second wrapping film 220 may be welded to the portion of the other side of the stack 100 in the third direction to which the second wrapping film 220 is not welded.

[0210] Therefore, the two wrapping films 210 and 220 can be used to surround the stack 100 and be welded to the stack 100. In addition to the step (f) of turning over the stack 100, the first wrapping step S522 for welding the first wrapping film 210 Fig. 9 (a) to (e) correspond to the second wrapping step S524 for welding the second wrapping film 220. Fig. 9 (f) to (k) in FIG. 1 . Therefore, since the manufacturing process of the electrode assembly 10 is simplified, the manufacturing equipment for the electrode assembly 10 can be simplified and the manufacturing cost of the electrode assembly 10 can be reduced.

[0211] In the wrapping step S520, after placing the wrapping film 200 on one side of the stack 100 in the first direction ((a) and (g)) and pressing and fixing a predetermined portion of the wrapping film 200 placed on one side of the stack 100 in the first direction using a fixing member Z ((b), (d), (h) and (j)), the roller R can move on one side of the stack 100 in the first direction and press the wrapping film 200 by hot pressing to be melted to one side of the stack 100 in the first direction ((b), (d), (h) and (j)), and the roller R can move on one side and the other side of the stack 100 in the third direction and press the wrapping film 200 by hot pressing to melt the wrapping film 200 to at least a portion of one side of the stack 100 in the third direction and a portion of the other side of the stack 100 in the third direction ((c) and (e)).

[0212] Therefore, simply by fixing the wrapping film 200 on one side of the stack 100 in the first direction with the fixing member Z, the wrapping film 200 can be fused to one side of the stack 100 in the first direction and one side and the other side of the stack 100 in the third direction. Therefore, when the wrapping film 200 is fused to the stack 100, the alignment of the stack 100 in the first direction can be easily maintained, and the wrapping film 200 can be fused to each of the one side of the stack 100 in the first direction and one side and the other side of the stack 100 in the third direction with minimal fixing. Therefore, since the manufacturing process of the electrode assembly 10 is simplified, the manufacturing equipment for the electrode assembly 10 can be simplified and the manufacturing cost of the electrode assembly 10 can be reduced.

[0213] In addition, since the wrap film 200 is welded to one side and the other side of the stack 100 in the third direction by pressing the wrap film 200 while moving the roller R in the first direction, when the wrap film 200 is welded, one end and the other end of the separator 120 in the third direction are naturally bent to be close to or in contact with one end and the other end in the third direction of the adjacent separator 120. Therefore, deformation and damage of the separator 120, destruction of alignment of the stack 100, and short circuit caused thereby can be prevented.

[0214] Furthermore, in the wrapping step S520, after a predetermined portion of the wrapping film 200 placed on one side of the stack 100 in the first direction is fixed by pressing with the fixing member Z ((h) and (j)), the roller R may be moved on one side and the other side of the stack 100 in the third direction, and the wrapping film 200 may be pressed by heat pressing to weld the wrapping film 200 to the wrapping films 200 already welded to one side and the other side of the stack 100 in the third direction ((i) and (k)). For example, as described above, the second wrapping film 220 may be welded to the first wrapping film 210.

[0215] Therefore, the stack 100 may be securely and conveniently surrounded by the wrapping film 200 .

[0216] In the wrapping step S520 , a process of heating the wrapping film 200 may be performed. For example, after heating the roller R, the wrapping film 200 may be heated and pressed with the heated roller R. Thus, the wrapping film 200 may be subjected to heat pressing (thermal fusion) to be fused to the stack 100 .

[0217] In the wrapping step S520, the wrapping film 200 may be fusion-bonded to the stack 100 while being heated to a first temperature. The first temperature may be higher than a second temperature to which the separator 120 is heated to be bonded to the electrode 110 (eg, lamination bonding).

[0218] Therefore, when the wrap film 200 is welded to the separator 120 of the stack 100, the separator 120 may also be welded to the wrap film 200 and / or the electrode 110, resulting in a strong bond between the wrap film 200 and the stack 100. Therefore, the wrap film 200 can fix and protect the stack 100 without falling off from the stack 100, thereby preventing the separator 120 from being deformed and damaged, and preventing the alignment of the stack 100 from being destroyed and the resulting short circuit. Here, the first temperature may be equal to or higher than 110 degrees Celsius and equal to or lower than 160 degrees Celsius, and the second temperature may be equal to or higher than 80 degrees Celsius and equal to or lower than 110 degrees Celsius. For example, the first temperature may be approximately equal to or higher than 120 degrees Celsius and equal to or lower than 140 degrees Celsius, and the second temperature may be approximately 100 degrees Celsius.

[0219] Therefore, the wrap film 200 can fix and protect the stack 100 without falling off the stack 100, thereby preventing the separator 120 from being deformed and damaged, and preventing alignment destruction of the stack 100 and the resulting short circuit.

[0220] It should be understood that the described embodiments are illustrative and not restrictive in all aspects, and the scope of the present invention will be indicated by the appended claims rather than the detailed description described. And the meaning and scope of the claims described later and all changes and modifications derived from equivalent concepts should be interpreted as being included in the scope of the present invention.

[0221] Although the present invention has been described with reference to the exemplary drawings, it should be understood that the present invention is not limited to the embodiments and drawings disclosed in this specification, and those skilled in the art will understand that various modifications can be made without departing from the scope and concept of the present invention. In addition, although the operational effects of the configuration according to the present invention are not explicitly described when describing the embodiments of the present invention, it should be understood that predictable effects will be recognized by the configuration.

Claims

1. An electrode assembly, comprising: A stack (100) formed by aligning a plurality of electrodes (110) and a plurality of separators (120) in a first direction and stacking them alternately; a wrapping film (200) surrounding and fused to the stack (100) to fix the plurality of electrodes (110) and the plurality of separators (120), wherein the electrode contacts (112) of the plurality of electrodes (110) are arranged on one side or the other side of the stack (100) in a second direction intersecting the first direction, and The wrapping film (200) surrounds one side and the other side of the stack (100) in the first direction and one side and the other side of the stack (100) in a third direction intersecting the first direction and the second direction, and the wrapping film (200) is at least welded to one side or the other side of the stack (100) in the first direction.

2. The electrode assembly according to claim 1, wherein: The wrapping film (200) is welded to one side or the other side of the stack (100) in the first direction and one side or the other side of the stack (100) in the third direction.

3. The electrode assembly according to claim 1 or 2, wherein: The wrapping film (200) comprises a first wrapping film (210) and a second wrapping film (220), wherein the first wrapping film (210) is bent to surround one side of the stack (100) in the first direction, at least a portion of one side of the stack (100) in the third direction, and at least a portion of another side of the stack (100) in the third direction, and the first wrapping film (210) is at least welded to one side of the stack (100) in the first direction, and The second wrapping film (220) is bent to surround the other side of the stack (100) in the first direction, at least a portion of one side of the stack (100) in the third direction, and at least a portion of the other side of the stack (100) in the third direction, and the second wrapping film (220) has two ends overlapping with the two ends of the first wrapping film (210) in the first direction on one side and the other side of the stack (100) in the third direction, and the second wrapping film (220) is at least welded to the other side of the stack (100) in the first direction and the two overlapping ends of the first wrapping film (210).

4. The electrode assembly according to claim 3, wherein: The first wrapping film (210) is welded to one side of the stack (100) in the first direction, at least a portion of one side of the stack (100) in the third direction, and at least a portion of the other side of the stack (100) in the third direction.

5. The electrode assembly according to any one of claims 1 to 4, wherein: Each of the plurality of diaphragms (120) extends further in one direction and another direction of the third direction than the plurality of electrodes (110) adjacent to each of the plurality of diaphragms (120), and When the wrapping film (200) is welded to the stack (100), one end and the other end of at least a portion of the plurality of diaphragms (120) in the third direction are bent to be close to or in contact with one end and the other end of a plurality of adjacent diaphragms (120) in the third direction.

6. The electrode assembly according to any one of claims 1 to 5, wherein: Each of the plurality of diaphragms (120) extends further in one direction and another direction of the third direction than the plurality of electrodes (110) adjacent to each of the plurality of diaphragms (120), and When the wrapping film (200) is welded to the stack (100), one end or the other end of each of two or more of the plurality of diaphragms (120) stacked continuously in the first direction in the third direction is bent together in one direction or the other direction of the first direction, wherein one or more of the plurality of electrodes (110) are located between the plurality of diaphragms (120).

7. The electrode assembly according to any one of claims 1 to 6, wherein: The wrapping film (200) extends in the second direction to surround a region corresponding to a predetermined section (S) of each of the plurality of diaphragms (120) in the second direction, and The predetermined section (S) is a section extending from the center of each of the plurality of diaphragms (120) in the second direction to one end and the other end of each of the plurality of diaphragms (120) in the second direction.

8. The electrode assembly according to claim 7, wherein: The wrapping film (200) is welded to one end or the other end of at least a portion of the plurality of diaphragms (120) in the third direction in a lengthwise manner corresponding to the predetermined section (S) in the second direction.

9. The electrode assembly according to claim 7 or 8, wherein: When the wrapping film (200) is welded to the stack (100), at least a first portion (P1) of the predetermined section (S) at one end in the third direction of each diaphragm of at least a portion of the plurality of diaphragms (120) is bent to be close to or in contact with each diaphragm of a plurality of adjacent diaphragms (120), and at least a second portion (P2) of the predetermined section (S) at the other end in the third direction of each diaphragm of at least a portion of the plurality of diaphragms (120) is bent to be close to or in contact with each diaphragm of a plurality of adjacent diaphragms (120).

10. The electrode assembly according to any one of claims 1 to 9, wherein: The plurality of electrodes (110) are located at one end or the other end of the stack (100) in the first direction, and The wrapping film (200) is welded to one side surface or the other side surface in the first direction of each electrode (110) located at the one end or the other end of the stack (100) in the first direction.

11. The electrode assembly according to any one of claims 1 to 10, wherein: The stack (100) includes a plurality of unit cells (C) aligned and stacked in the first direction, Each of the plurality of unit cells (C) is composed of a portion of the plurality of electrodes (110) and a portion of the plurality of separators (120) stacked alternately, The part of the electrodes (110) and the part of the separators (120) constituting each unit cell of the plurality of unit cells (C) are bonded to each other, and The wrapping film (200) surrounds the stack (100) and is welded to the stack (100) to fix the plurality of unit cells (C).

12. The electrode assembly according to any one of claims 1 to 11, wherein: The welding is performed by heat pressing.

13. The electrode assembly according to any one of claims 1 to 12, wherein: The wrapping film (200) is made of a material including polyethylene terephthalate (PET) and ethylene vinyl acetate (EVA).

14. The electrode assembly according to any one of claims 1 to 13, wherein: The flexural rigidity of the wrapping film (200) is greater than the flexural rigidity of the plurality of diaphragms (120).

15. A method for manufacturing an electrode assembly according to any one of claims 1 to 14, the method comprising: a stacking step (S510), wherein the stacking step forms a stack (100); as well as A wrapping step (S520), wherein the wrapping step uses a wrapping film (200) to surround one side and the other side of the stack (100) in a first direction and one side and the other side of the stack (100) in a third direction, and the wrapping film (200) is at least welded to one side or the other side of the stack (100) in the first direction.

16. The method according to claim 15, wherein: The wrapping film (200) comprises a first wrapping film (210) and a second wrapping film (220), Wherein, the wrapping step (S520) includes: a first wrapping step (S522), wherein the first wrapping step welds the first wrapping film (210) to one side of the stack (100) in the first direction, to at least a portion of one side of the stack (100) in the third direction, and to at least a portion of the other side of the stack (100) in the third direction; and A second wrapping step (S524), in which the second wrapping step, after flipping the stack (100) to interchange one side and the other side of the stack (100) in the first direction, welds the second wrapping film (220) to one side of the stack (100) in the first direction and to at least two ends of the first wrapping film (210) located on one side and the other side of the stack (100) in the third direction.

17. The method according to claim 15 or 16, wherein: The wrapping step (S520) includes: after placing the wrapping film (200) on one side of the stack (100) in the first direction and pressing and fixing a predetermined area of ​​the wrapping film (200) placed on one side of the stack (100) in the first direction by using a fixing member (Z), moving a roller (R) in the third direction on one side of the stack (100) in the first direction to press and fuse the wrapping film (200) to one side of the stack (100) in the first direction by heat pressing, and moving the roller (R) in the first direction on one side and the other side of the stack (100) in the third direction to press and fuse the wrapping film (200) to at least a portion of one side of the stack (100) in the third direction and at least a portion of the other side of the stack (100) in the third direction by heat pressing.

18. The method according to any one of claims 15 to 17, wherein: The wrapping step (S520) includes: after placing the wrapping film (200) on one side of the stack (100) in the first direction and pressing and fixing a predetermined area of ​​the wrapping film (200) placed on one side of the stack (100) in the first direction using a fixing member (Z), moving a roller (R) in the first direction on one side and the other side of the stack (100) in the third direction to press and weld the wrapping film (200) to the wrapping film (200) that has been welded to one side and the other side of the stack (100) in the third direction by heat pressing.

19. The method according to any one of claims 15 to 18, wherein: In the wrapping step (S520), the wrapping film (200) is heated to a first temperature and welded to the stack (100), The first temperature is higher than a second temperature to which one or more of the plurality of membranes (120) are heated to bond to one or more of the plurality of electrodes (110).

20. The method according to claim 19, wherein: The first temperature is equal to or higher than 110 degrees Celsius and lower than 160 degrees Celsius, and the second temperature is equal to or higher than 80 degrees Celsius and lower than 110 degrees Celsius.

Images