Electrode assembly and method for manufacturing the electrode assembly

Abstract

The present invention provides an electrode assembly including a laminate 100 in which a plurality of electrodes 110 and a separation membrane 120 are alternately laminated in a first direction and are aligned and laminated, and a wrapping film 200 that surrounds the laminate 100, is fused to the laminate 100, and fixes the plurality of electrodes 110 and the separation membrane 120. The electrode tabs 112 of the plurality of electrodes 110 are disposed on one side or the other side in a second direction intersecting the first direction of the laminate 100. The wrapping film 200 surrounds one side and the other side of the laminate 100 in the first direction and one side and the other side in a third direction intersecting the first direction and the second direction of the laminate 100, and is fused to at least one side or the other side of the laminate 100 in the first direction. Therefore, deformation and breakage of the separation membrane 120, disturbance of the alignment state of the laminate 100, and short circuit caused thereby can be prevented.

Description

Technical Field

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

[0002] The present invention relates to an electrode assembly and a method for manufacturing the electrode assembly, and more particularly, to an electrode assembly and a method for manufacturing the electrode assembly in which deformation and breakage of a separator, disturbance of the alignment state of a laminate, and short circuit caused thereby are prevented.

Background Art

[0003] A secondary battery means a battery that can be charged and discharged, unlike a primary battery that cannot be charged. Secondary batteries are used not only as power sources for small and advanced electronic devices such as mobile phones, PDAs, and notebook computers, but also as energy storage systems (ESS), electric vehicles (EV), or hybrid electric vehicles (HEV).

[0004] To manufacture these secondary batteries, first, an electrode active material slurry is applied to a positive electrode current collector and a negative electrode current collector to manufacture a positive electrode (Cathode) and a negative electrode (Anode), and these are laminated on both sides of a separator (Separator) to form an electrode assembly having a predetermined shape. Then, the electrode assembly is housed in a battery case, and after injecting an electrolyte, it is sealed.

[0005] There are various types of electrode assemblies used in pouch-type secondary batteries. Among them, a lamination & stack type (L&S) electrode assembly is an electrode assembly manufactured by first manufacturing unit cells using a positive electrode, a separator, and a negative electrode, and then laminating these unit cells.

[0006] Conventionally, even when these unit cells were stacked, they did not adhere to each other or had very weak adhesion, and the unit cells often detached from their fixed positions, resulting in a decrease in alignment. To prevent this, a method of attaching a tape to the outer surface of the stacked unit cells has been proposed.

[0007] However, when attaching the tape, there were problems such that the separation membrane was partially bent by the tape, causing damage to the separation membrane or the electrode or a short circuit. Also, in the electrolyte injection process or the gas venting process, the tape (T) was likely to fall off the stacked unit cells, and the separation membrane 120 was deformed, resulting in a short circuit.

[0008] To solve such problems, Korean Patent Publication No. 10-2021-0127532 provides an electrode assembly in which a plurality of unit cells are stacked while adhering to each other via an adhesive.

[0009] However, in the above prior art, since the adhesive must be applied to the unit cells and then the unit cells must be aligned and stacked, the manufacturing cost and manufacturing time increase.

Prior Art Documents

Patent Documents

[0010] (Patent Document 0001) Korean Patent Publication No. 10-2021-0127532

Summary of the Invention

Problems to be Solved by the Invention

[0011] The present invention was devised to solve the above-described problems, and an object thereof is to provide an electrode assembly in which deformation and damage of the separation membrane, disturbance of the alignment state of the stacked body, and a short circuit caused thereby are prevented.

[0012] Another object of the present invention is to provide an electrode assembly that firmly and correctly fixes the electrode and the separation membrane in an aligned state.

[0013] An object of the present invention is to provide an electrode assembly in which a wrapping film is strongly bonded to a laminate.

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

[0015] Another object of the present invention is to provide an electrode assembly in which the performance of the secondary battery does not deteriorate and the life is not shortened even when the laminate is surrounded by a wrapping film.

[0016] Another object of the present invention is to provide an electrode assembly in which the energy density of the secondary battery increases.

[0017] The technical problems of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention not mentioned can be understood from the following description and can be more clearly understood from the embodiments of the present invention. Also, it is easy to understand that the objects and advantages of the present invention can be realized by the means and combinations thereof shown in the claims.

Means for Solving the Problems

[0018] In order to solve the above-mentioned problems, the present invention provides an electrode assembly including a laminate 100 and a wrapping film 200.

[0019] The laminate 100 may be formed by alternately laminating a plurality of electrodes 110 and a separator 120 in a first direction.

[0020] The laminate 100 may be formed by alternately aligning and laminating the plurality of electrodes 110 and the separator 120 in a first direction.

[0021] The wrapping film 200 surrounds the laminate 100 and is fused to the laminate 100 to fix the plurality of electrodes 110 and the separator 120.

[0022] The electrode tabs 112 of the plurality of electrodes 110 may be arranged on one side or the other side in a second direction intersecting the first direction of the laminate 100.

[0023] The wrapping film 200 surrounds one side and the other side of the laminate 100 in the first direction, and one side and the other side in a third direction intersecting the first direction and the second direction of the laminate 100, and may be fused to at least one side or the other side of the laminate 100 in the first direction.

[0024] In one embodiment, the wrapping film 200 may be fused to one side or the other side of the laminate 100 in the first direction, and one side or the other side of the laminate 100 in the third direction.

[0025] In one embodiment, the wrapping film 200 may include a first wrapping film 210 and a second wrapping film 220.

[0026] The first wrapping film 210 may be folded to surround at least a part of one side in the first direction, at least a part of one side in the third direction, and at least a part of the other side in the third direction of the laminate 100.

[0027] The first wrapping film 210 may be fused to at least one side of the laminate 100 in the first direction.

[0028] The second wrapping film 220 may be folded to surround at least a part of the other side in the first direction, at least a part of one side in the third direction, and at least a part of the other side in the third direction of the laminate 100.

[0029] Both ends of the second wrapping film 220 may overlap both ends of the first wrapping film 210 in the first direction on one side and the other side of the laminate 100 in the third direction.

[0030] The second wrapping film 220 may be fused to at least the other side of the laminate 100 in the first direction and both ends of the overlapping first wrapping film 210.

[0031] In one embodiment, the first wrapping film 210 may be fused to at least a part of one side in the first direction, at least a part of one side in the third direction, and at least a part of the other side in the third direction of the laminate 100.

[0032] In one embodiment, each of the separation membranes 120 may further extend in one and the other directions in the third direction than the electrode 110 adjacent to each separation membrane 120.

[0033] When the wrapping film 200 is fused to the laminate 100, one side end and the other side end of at least a part of the separation membrane 120 in the third direction may be bent and may be close to or in contact with one side end and the other side end of the adjacent separation membrane 120 in the third direction.

[0034] In one embodiment, each of the separation membranes 120 may further extend in one and the other directions in the third direction than the electrode 110 adjacent to each separation membrane 120.

[0035] When the wrapping film 200 is fused to the laminate 100, one side end or the other side end of the plurality of separation membranes 120 continuously laminated in the first direction via the electrode 110 may all be bent in one direction in the first direction or bent in the other direction in the first direction.

[0036] In one embodiment, the wrapping film 200 may extend in the second direction and surround a portion corresponding to a predetermined section (S) in the second direction of the plurality of separation membranes 120.

[0037] The predetermined section (S) may be a section in the second direction extending from the center of the plurality of separation membranes 120 to one side end and the other side end in the second direction.

[0038] In one embodiment, the wrapping film 200 may be fused to one end or the other end of at least some of the plurality of separation membranes 120 in the third direction.

[0039] The wrapping film 200 may be fused longitudinally in the second direction to a portion corresponding to the predetermined section (S) among one end or the other end of the at least some of the separation membranes 120 in the third direction.

[0040] In one embodiment, when the wrapping film 200 is fused to the laminate 100, at least a first portion (P1) belonging to at least the predetermined section (S) among one ends of at least some of the separation membranes 120 in the third direction may be bent to be close to or in contact with an adjacent separation membrane 120.

[0041] Also, at least a second portion (P2) belonging to at least the predetermined section (S) among the other ends of at least some of the separation membranes 120 in the third direction may be bent to be close to or in contact with an adjacent separation membrane 120.

[0042] In one embodiment, the electrode 110 may be located at one end or the other end of the laminate 100 in the first direction.

[0043] The wrapping film 200 may be fused to one side or the other side of the electrode 110 located at one end or the other end of the laminate 100 in the first direction.

[0044] In one embodiment, the laminate 100 may be composed of a plurality of unit cells (C) stacked in alignment in the first direction.

[0045] Each of the unit cells (C) may be composed of some of the plurality of electrodes 110 and separation membranes 120 that are alternately stacked.

[0046] The electrodes 110 and separation membranes 120 forming each of the unit cells (C) may be joined to each other.

[0047] The wrapping film 200 can surround the laminate 100 and be fused to the laminate 100 to fix the plurality of unit cells (C).

[0048] In one embodiment, the fusing can be performed by a hot pressing method.

[0049] In one embodiment, the wrapping film 200 can be made of a material containing polyethylene terephthalate (PET) and ethylene vinyl acetate (EVA).

[0050] In one embodiment, the wrapping film 200 may have a bending resistance rigidity greater than that of the separation film 120.

[0051] Further, in order to solve the above-described problems, the present invention provides a method (S500) for manufacturing an electrode assembly including a lamination step (S510) and a wrapping step (S520).

[0052] In the lamination step (S510), the laminate 100 can be formed.

[0053] In the wrapping step (S520), the wrapping film 200 may surround one side and the other side of the laminate 100 in the first direction, and one side and the other side of the laminate 100 in the third direction. Also, the wrapping film 200 can be fused to at least one side or the other side of the laminate 100 in the first direction.

[0054] In one embodiment, the wrapping film 200 may include a first wrapping film 210 and a second wrapping film 220.

[0055] The wrapping step (S520) may include a first wrapping step (S522) and a second wrapping step (S524).

[0056] In the first wrapping step (S522), the first wrapping film 210 can be fused to at least a part of one side in the first direction, at least a part of one side in the third direction, and at least a part of the other side in the third direction of the laminate 100.

[0057] In the second wrapping step (S524), after turning over the laminate 100 so that one side and the other side change with each other in the first direction, the second wrapping film 220 is fused to one side in the first direction of the laminate 100, and on one side and the other side in the third direction of the laminate 100, the second wrapping film 220 can be fused to at least both ends of the first wrapping film 210.

[0058] In one embodiment, in the wrapping step (S520), the wrapping film 200 is placed on one side in the first direction of the laminate 100, and after a predetermined portion of the wrapping film 200 placed on one side in the first direction of the laminate 100 is fixed by pressing with a fixing member (Z), on one side in the first direction of the laminate 100, while moving the roller (R) in the third direction, the wrapping film 200 is pressed to thermally fuse the wrapping film 200 to one side in the first direction of the laminate 100, and on one side and the other side in the third direction of the laminate 100, while moving the roller (R) in the first direction, the wrapping film 200 is pressed to thermally fuse the wrapping film 200 to at least a part of one side in the third direction and at least a part of the other side in the third direction of the laminate 100.

[0059] In one embodiment, in the wrapping step (S520), the wrapping film 200 is placed on one side in the first direction of the laminate 100, and after a predetermined portion of the wrapping film 200 placed on one side in the first direction of the laminate 100 is fixed by pressing with a fixing member (Z), on one side and the other side in the third direction of the laminate 100, while moving the roller (R) in the first direction, the wrapping film 200 is pressed to thermally fuse the wrapping film 200 to the wrapping film 200 that has already been fused to one side and the other side in the third direction of the laminate 100.

[0060] In one embodiment, in the wrapping step (S520), the wrapping film 200 may be fused to the laminate 100 while being heated to a first temperature.

[0061] The first temperature may be higher than a second temperature at which the separation membrane 120 is heated so that the separation membrane 120 is joined to the electrode 110.

[0062] In one embodiment, the first temperature may be greater than or equal to 110 degrees Celsius and less than 160 degrees Celsius.

[0063] The second temperature may be greater than or equal to 80 degrees Celsius and less than 110 degrees Celsius.

Advantages of the Invention

[0064] According to an embodiment of the present invention, the electrode assembly 10 may include a laminate 100 formed by alternately laminating a plurality of electrodes 110 and separation membranes 120 in a first direction, and a wrapping film 200 that surrounds the laminate 100 and is fused to the laminate 100 to fix the plurality of electrodes 110 and the separation membranes 120.

[0065] Thereby, since the wrapping film 200 surrounds the laminate 100 and is fused to the laminate 100, the electrodes 110 and the separation membranes 120 can be firmly fixed in an aligned state, and the electrodes 110 and the separation membranes 120 can be protected. For this reason, deformation and breakage of the separation membrane 120, disturbance of the alignment state of the laminate 100, and short circuit due to this can be prevented. In particular, even when a swelling phenomenon occurs in which the electrodes 110 and the like swell after impregnation (wetting) with the electrolytic solution, the wrapping film 200 can fix and protect the laminate 100 without falling off from the laminate 100, so that the separation membrane 120 is not deformed or damaged, the alignment state of the laminate 100 is not disturbed, and a short circuit does not occur.

[0066] In addition, since the electrode 110 and the separation membrane 120 can be firmly fixed in an aligned state by the wrapping film 200, when transporting the electrode assembly 10, it is possible to prevent the laminate 100 from bending. Therefore, it is possible to prevent deformation and breakage of the separation membrane 120 and disturbance of the alignment state of the laminate 100.

[0067] According to an embodiment of the present invention, the electrode tabs 112 of the plurality of electrodes 110 may be arranged on one side or the other side in a second direction intersecting the first direction of the laminate 100. The wrapping film 200 surrounds one side and the other side in the first direction of the laminate 100, and one side and the other side in a third direction intersecting the first direction and the second direction of the laminate 100, and may be fused to at least one side or the other side in the first direction of the laminate 100.

[0068] Thereby, avoiding the electrode tabs 112 of the electrodes 110, the laminate 100 can be easily surrounded by the wrapping film 200, and the wrapping film 200 can be easily fused to the laminate 100. Therefore, the electrode assembly 10 can be easily manufactured, and the manufacturing cost of the electrode assembly 10 can be reduced.

[0069] According to an embodiment of the present invention, the wrapping film 200 may be fused to one side or the other side in the first direction of the laminate 100 and one side or the other side in the third direction of the laminate 100.

[0070] Thereby, the area where the wrapping film 200 is fused to the laminate 100 increases, or the number of separation membranes 120 to which the wrapping film 200 is fused increases, so that the electrode 110 and the separation membrane 120 can be more firmly fixed in an aligned state. Therefore, it is possible to prevent deformation and breakage of the separation membrane 120, disturbance of the alignment state of the laminate 100, and short circuit caused thereby.

[0071] 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 at least a part of one side in the first direction, at least a part of one side in the third direction, and at least a part of the other side in the third direction of the laminate 100, and may be fused to at least one side in the first direction of the laminate 100. The second wrapping film 220 may be bent to surround at least a part of the other side in the first direction, at least a part of one side in the third direction, and at least a part of the other side in the third direction of the laminate 100. Both ends thereof overlap both ends of the first wrapping film 210 in the first direction on one side and the other side in the third direction of the laminate 100, and may be fused to at least the other side in the first direction of the laminate 100 and both ends of the overlapping first wrapping film 210.

[0072] Thus, since the laminate 100 is surrounded by the two wrapping films 210 and 220 and the two wrapping films 200 are fused to the laminate 100, the electrode assembly 10 can be easily manufactured with a simple configuration and at a low cost.

[0073] According to an embodiment of the present invention, the first wrapping film 210 may be fused to at least a part of one side in the first direction, at least a part of one side in the third direction, and at least a part of the other side in the third direction of the laminate 100.

[0074] As a result, the area where the first wrapping film 210 is fused to the laminate 100 increases, or the number of separator films 120 to which the first wrapping film 210 is fused increases, so that the electrode 110 and the separator film 120 can be more firmly fixed in an aligned state. Therefore, deformation and breakage of the separator film 120, disturbance of the alignment state of the laminate 100, and short circuit caused thereby can be prevented.

[0075] According to an embodiment of the present invention, each separation membrane 120 may further extend in one and the other directions of the third direction than the electrode 110 adjacent to each separation membrane 120. When the wrapping film 200 is fused to the laminate 100, one end and the other end of at least a part of the separation membrane 120 in the third direction may be bent and may be close to or in contact with one end and the other end of the adjacent separation membrane 120 in the third direction.

[0076] Thereby, since the wrapping film 200 surrounds the laminate 100 while pressing the separation membrane 120, the electrode 110 and the separation membrane 120 can be more firmly fixed in an aligned state. Further, since one end and the other end of the separation membrane 120 in the third direction are fixed in a bent state, the pressure applied to one side and the other side of the laminate 100 in the third direction can be easily absorbed, and one end and the other end of the separation membrane 120 in the third direction are arranged close to one end and the other end of the adjacent separation membrane 120 in the third direction, so the strength of one side and the other side of the laminate 100 in the third direction can be increased. Therefore, the laminate 100 and the separation membrane 120 can be protected. For this reason, deformation and breakage of the separation membrane 120, disturbance of the alignment state of the laminate 100, and short circuit due to this can be prevented. In particular, even when a swelling phenomenon occurs in which the electrode 110 and the like swell after impregnation (wetting) of the electrolytic solution, the separation membrane 120 is not deformed or broken, the alignment state of the laminate 100 is not disturbed, and no short circuit occurs. Further, when transporting the electrode assembly 10, bending of the laminate 100 can be prevented. For this reason, deformation and breakage of the separation membrane 120 and disturbance of the alignment state of the laminate 100 can be prevented.

[0077] Further, even if the alignment state of the laminate 100 is disturbed, the electrodes 110 (for example, a pair of electrodes arranged on one side and the other side in the first direction of the separation membrane) are separated from the bent one end or the other end of the separation membrane 120 in the third direction, and the possibility of being directly electrically connected to the battery case can be greatly reduced. For this reason, a short circuit can be prevented.

[0078] According to an embodiment of the present invention, each separation membrane 120 may further extend in one and the other directions of the third direction than the electrode 110 adjacent to each separation membrane 120. When the wrapping film 200 is fused to the laminate 100, one end or the other end of the third direction of a plurality of separation membranes 10 continuously laminated in the first direction via the electrode 110 may all bend to one side of the first direction or bend to the other side of the first direction.

[0079] Thereby, while pressing a plurality of separation membranes 120 to which the wrapping film 200 is continuously laminated in a similar direction to surround the laminate 100, the electrode 110 and the separation membrane 120 can be fixed more firmly in an aligned state. In addition, one end or the other end of the third direction of a plurality of separation membranes 120 continuously laminated can be densely arranged in the third direction, so that the strength of one side and the other side of the laminate 100 in the third direction can be increased. Therefore, the laminate 100 and the separation membrane 120 can be protected. For this reason, deformation and breakage of the separation membrane 120, disturbance of the alignment state of the laminate 100, and short circuit caused thereby can be prevented.

[0080] According to an embodiment of the present invention, the wrapping film 200 may extend in the second direction and surround a portion corresponding to a predetermined section (S) in the second direction of a plurality of separation membranes 120. The predetermined section (S) may be a section in the second direction extending from the center to one end and the other end of a plurality of separation membranes 120 in the second direction.

[0081] Thereby, the wrapping film 200 surrounds the central portion, one end portion, and the other end portion in the second direction of a plurality of separation membranes 120 at once, but may surround them long in the second direction. For this reason, since the wrapping film 200 can stably surround the laminate 100, the electrode 110 and the separation membrane 120 can be fixed more firmly in an aligned state. For this reason, deformation and breakage of the separation membrane 120, disturbance of the alignment state of the laminate 100, and short circuit caused thereby can be prevented.

[0082] According to an embodiment of the present invention, the wrapping film 200 is fused to one side end or the other side end in the third direction of at least some of the plurality of separation membranes 120, but may be fused long in the second direction to a portion corresponding to a predetermined section (S) of one side end or the other side end in the third direction.

[0083] As a result, the area where the wrapping film 200 is fused to the laminate 100 increases, or the number of separation membranes 120 to which the wrapping film 200 is fused increases, so that the electrode 110 and the separation membrane 120 can be fixed more firmly in an aligned state. Further, since the wrapping film 200 is fused long in the second direction to the central portion, one side end portion, and the other side end portion in the second direction of the separation membrane 120 surrounded by the wrapping film 200 at once, the electrode 110 and the separation membrane 120 can be fixed more firmly in an aligned state. Therefore, it is possible to prevent deformation and breakage of the separation membrane 120, disturbance of the alignment state of the laminate 100, and short circuit caused thereby.

[0084] According to an embodiment of the present invention, when the wrapping film 200 is fused to the laminate 100, at least a first portion (P1) belonging to at least a predetermined section (S) of one side end in the third direction of at least some of the separation membranes 120 may bend and come close to or contact an adjacent separation membrane 120, and at least a second portion (P2) belonging to at least a predetermined section (S) of the other side end in the third direction of at least some of the separation membranes 120 may bend and come close to or contact an adjacent separation membrane 120.

[0085] As a result, while the wrapping film 200 surrounds the laminate 100 while pressing the separation membrane 120, since the central portion, one side end portion, and the other side end portion of the separation membrane 120 in the second direction are surrounded long in the second direction at once, the electrode 110 and the separation membrane 120 can be fixed more firmly in an aligned state. Further, although one side end portion and the other side end portion of the separation membrane 120 in the third direction are fixed in a bent state, since the central portion, one side end portion, and the other side end portion of one side end portion and the other side end portion of the separation membrane 120 in the third direction are bent and fixed long in the second direction at once, the pressure applied to one side and the other side in the third direction of the laminate 100 can be easily absorbed. Further, although one side end portion and the other side end portion of the separation membrane 120 in the third direction are arranged close to one side end portion and the other side end portion of the adjacent separation membrane 120 in the third direction, since the central portion, one side end portion, and the other side end portion of one side end portion and the other side end portion of the separation membrane 120 in the third direction are arranged long and close in the second direction at once, the strength of one side and the other side in the third direction can be increased. Thus, the separation membrane 120 can be protected. For this reason, deformation and breakage of the separation membrane 120, disturbance of the alignment state of the laminate 100, and short circuit due to this can be prevented.

[0086] Further, even if the alignment state of the laminate 100 is disturbed, the electrodes 110 (for example, a pair of electrodes arranged on one side and the other side in the first direction of the separation membrane) are separated by the bent one side end portion or the other side end portion of the separation membrane 120 in the third direction, but since they are separated long in the second direction by the central portion, one side end portion, and the other side end portion of the bent one side end portion or the other side end portion of the separation membrane 120 in the third direction, the possibility that the electrodes 110 are directly electrically connected to the battery case can be greatly reduced. For this reason, a short circuit can be prevented.

[0087] According to an embodiment of the present invention, the electrode 110 may be located at one end or the other end of the laminate 100 in the first direction. The wrapping film 200 may be fused to one side surface or the other side surface in the first direction of the electrode 110 located at one end or the other end of the laminate 100 in the first direction.

[0088] Thus, in order to insulate the electrode 110 located at the outermost contour of the laminate 100 in the first direction from a battery case (not shown), the separator 120 located at one end or the other end of the laminate 100 in the first direction can be replaced with the wrapping film 200. For this reason, since the thickness of the electrode assembly 10 can be reduced, the energy density of the secondary battery including the electrode assembly 10 can be increased.

[0089] According to an embodiment of the present invention, the laminate 100 may be composed of a plurality of unit cells (C) that are aligned and laminated in the first direction. Each unit cell (C) may be composed of some of the plurality of electrodes 110 and separators 120 that are alternately laminated. The electrodes 110 and separators 120 forming each unit cell (C) may be joined to each other. The wrapping film 200 can surround the laminate 100 and be fused to the laminate 100 to fix the plurality of unit cells (C).

[0090] Thus, since the electrodes 110 and separators 120 of each of the plurality of unit cells (C) constituting the laminate 100 surrounded and fused by the wrapping film 200 are joined to each other in advance, the electrodes 110 and separators 120 can be more firmly fixed in an aligned state, and the electrodes 110 and separators 120 can be safely protected. For this reason, deformation and breakage of the separator 120, disturbance of the alignment state of the laminate 100, and short circuit due to this can be prevented.

[0091] According to an embodiment of the present invention, the fusion bonding can be performed by a thermocompression bonding method.

[0092] Thus, the wrapping film 200 may be easily fused to the laminate 100 with a simple configuration and at a low cost.

[0093] According to an embodiment of the present invention, the wrapping film 200 can be composed of a material including polyethylene terephthalate (PET) and ethylene vinyl acetate (EVA).

[0094] As a result, not only the fixing force and bonding strength of the wrapping film 200 are excellent, but also the heat exchange performance of the wrapping film 200 is excellent. Therefore, the electrode 110 and the separator 120 are firmly fixed in an aligned state and can be safely protected. Even when surrounded by the wrapping film 200, the laminate 100 does not overheat, the performance of the secondary battery does not deteriorate, and the lifespan is not shortened. In addition, the wrapping film 200 has excellent insulation performance, and since the outermost separator 120 of the laminate 100 can be omitted, the thickness of the electrode assembly 10 can be reduced. Also, since a commercially available film can be used as the wrapping film 200, the electrode assembly 10 can be easily manufactured, and the manufacturing cost of the electrode assembly 10 can be reduced.

[0095] According to an embodiment of the present invention, the wrapping film 200 may have a bending resistance rigidity greater than that of the separator 120.

[0096] As a result, the wrapping film 200 can firmly and correctly fix the electrode 110 and the separator 120 in an aligned state.

[0097] According to an embodiment of the present invention, the method (S500) for manufacturing an electrode assembly may include a laminating step (S510) of forming the laminate 100, and a wrapping step (S520) of surrounding one side and the other side of the laminate 100 in a first direction and one side and the other side of the laminate 100 in a third direction with the wrapping film 200, and fusing the wrapping film 200 to at least one side or the other side of the laminate 100 in the first direction.

[0098] As a result, the electrode 110 and the separator 120 can be firmly fixed in an aligned state, and an electrode assembly 10 that can protect the electrode 110 and the separator 120 can be manufactured. Therefore, deformation and breakage of the separator 120, disturbance of the alignment state of the laminate 100, and short circuits caused thereby can be prevented.

[0099] 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 fusing the first wrapping film 210 to at least a part of one side in the first direction, at least a part of one side in the third direction, and at least a part of the other side in the third direction of the laminate 100, and after turning over the laminate 100 so that one side and the other side change with each other in the first direction, fusing the second wrapping film 220 to one side in the first direction of the laminate 100, and fusing the second wrapping film 220 to at least both ends of the first wrapping film 210 on one side and the other side in the third direction of the laminate 100. A second wrapping step (S524) may be included.

[0100] As a result, the laminate 100 can be surrounded and fused to the laminate 100 using two wrapping films 210 and 220. At this time, the first wrapping step (S522, a to e in FIG. 9) of fusing the first wrapping film 210 and the second wrapping step (S524, f to k in FIG. 9) of fusing the second wrapping film 220 can correspond to each other sequentially except for the step (f) of turning over the laminate 100. Therefore, since the manufacturing process of the electrode assembly 10 becomes simple, the manufacturing equipment of the electrode assembly 10 becomes simple, and the manufacturing cost of the electrode assembly 10 can be reduced.

[0101] According to an embodiment of the present invention, in the wrapping step (S520), a wrapping film 200 is placed on one side of the laminate 100 in the first direction. After a predetermined portion of the wrapping film 200 placed on one side of the laminate 100 in the first direction is pressed and fixed by a fixing member (Z), while moving the roller (R) in the third direction on one side of the laminate 100 in the first direction, the wrapping film 200 is pressed to heat-seal the wrapping film 200 to one side of the laminate 100 in the first direction by a thermocompression bonding method. On one side and the other side of the laminate 100 in the third direction, while moving the roller (R) in the first direction, the wrapping film 200 is pressed to heat-seal the wrapping film 200 to at least a part of one side and at least a part of the other side of the laminate 100 in the third direction.

[0102] Thereby, when the wrapping film 200 is fixed to one side of the laminate 100 in the first direction by the fixing member (Z), the wrapping film 200 can be heat-sealed to one side of the laminate 100 in the first direction, one side in the third direction, and the other side in the third direction by a thermocompression bonding method. Therefore, when the wrapping film 200 is fused to the laminate 100, the alignment state of the laminate 100 laminated in the first direction can be easily maintained, and the wrapping film 200 can be fused to one side of the laminate 100 in the first direction, one side in the third direction, and the other side in the third direction with a minimum fixing operation. Thus, since the manufacturing process of the electrode assembly 10 is simplified, the manufacturing equipment of the electrode assembly 10 becomes simple, the manufacturing cost of the electrode assembly 10 can be reduced, and the manufacturing time can be shortened.

[0103] In addition, in order to press the wrapping film 200 while moving the roller (R) in the first direction to fuse the wrapping film 200 to one side and the other side of the laminate 100 in the third direction, while the wrapping film 200 is being fused, the one-side end and the other-side end of the separation film 120 in the third direction may be bent naturally and come close to or contact the one-side end and the other-side end of the adjacent separation film 120 in the third direction. Therefore, it is possible to prevent deformation and breakage of the separation film 120, disturbance of the alignment state of the laminate 100, and short circuit caused thereby.

[0104] According to an embodiment of the present invention, in the wrapping step (S520), a wrapping film 200 is placed on one side of the laminate 100 in the first direction, and a predetermined portion of the wrapping film 200 placed on one side of the laminate 100 in the first direction is pressed and fixed with a fixing member (Z). Then, on one side and the other side of the laminate 100 in the third direction, while moving the roller (R) in the first direction, the wrapping film 200 is pressed, and the wrapping film 200 can be heat-sealed to the wrapping film 200 already fused to one side and the other side of the laminate 100 in the third direction by a heat-sealing method.

[0105] Thereby, the laminate 100 can be firmly and easily surrounded by the wrapping film 200.

[0106] According to an embodiment of the present invention, in the wrapping step (S520), the wrapping film 200 may be fused to the laminate 100 while being heated to a first temperature. The first temperature may be higher than a second temperature at which the separation film 120 is heated for the separation film 120 to be joined to the electrode 110.

[0107] Thereby, when the wrapping film 200 is fused to the separation film 120 of the laminate 100, the separation film 120 can also be fused to the wrapping film 200 and / or the electrode 110. Therefore, the wrapping film 200 can be strongly bonded to the laminate 100. For this reason, the wrapping film 200 can fix and protect the laminate 100 without falling off from the laminate 100, so that the separation film 120 is not deformed or damaged, the alignment state of the laminate 100 is not disturbed, and no short circuit occurs.

[0108] According to an embodiment of the present invention, the first temperature may be greater than or the same as 110 degrees Celsius and less than 160 degrees Celsius. The second temperature may be greater than or the same as 80 degrees Celsius and less than 110 degrees Celsius.

[0109] As a result, the wrapping film 200 can fix and protect the laminate 100 without falling off from the laminate 100, so that the separation membrane 120 is not deformed or damaged, the alignment state of the laminate 100 is not disturbed, and no short circuit occurs.

[0110] The above-described effects and the specific effects of the present invention will be described and described while explaining the embodiments for carrying out the following invention.

Brief Description of the Drawings

[0111]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0112] The above-described objects, features, and advantages will be described in detail below with reference to the accompanying drawings, so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement the technical idea of the present invention. In the description of the present invention, when a specific description of a known technique related to the present invention is determined to obscure the gist 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. The same reference numerals in the drawings are used to indicate the same or similar components.

[0113] For example, although first, second, etc. are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are merely used to distinguish one component from another, and of course, the first component may be the second component unless otherwise stated.

[0114] Unless otherwise stated throughout the specification, each component may be singular or plural.

[0115] Hereinafter, the statement that an arbitrary configuration is arranged "above (or below)" a component or "on (or under)" a component means that the arbitrary configuration is not only arranged in contact with the upper surface (or lower surface) of the above component, but also other configurations may be interposed between the above component and an arbitrary configuration arranged "above (or below)" the above component.

[0116] Also, when a certain component is described as being "connected", "coupled", or "connected" to another component, it should be understood that the above components may be directly connected or connected to each other, but other components may "intervene" between the components, or each component may be "connected", "coupled", or "connected" through another component.

[0117] As used herein, singular expressions include plural expressions unless the context clearly indicates otherwise. Terms such as "composed of" or "including" in this application should not necessarily be construed as including all of the plurality of components or steps described in the specification. Some of the components or steps may not be included, or may be construed as including additional components or steps.

[0118] Figures 1 and 2 are a perspective view and a front view showing a laminate of an electrode and a separator according to an embodiment of the present invention. Figure 3 is a perspective view showing a conventional electrode assembly with a tape attached to the laminate of Figures 1 and 2. Figures 4 and 5 are 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 fused to the laminate of Figures 1 and 2. Figure 6 is a perspective view showing either separator of the electrode assemblies of Figures 4 and 5. Figure 7 is a front view showing an electrode assembly according to another embodiment of the present invention. Figure 8 is a flowchart of a method for manufacturing an electrode assembly according to an embodiment of the present invention. Figure 9 is a drawing sequentially showing the method for manufacturing the electrode assemblies of Figures 4 and 5.

[0119] [Conventional Electrode Assembly] Referring to Figures 1 to 3, the conventional electrode assembly may include a laminate 100 and a tape (T, Figure 3). When the electrode assembly is housed in a battery case (not shown) and the battery case is sealed after an electrolyte is injected into the interior of the battery case, a secondary battery (not shown) can be formed. Hereinafter, the laminate 100 and the tape (T) will be examined.

[0120] The laminate 100 can be composed of a plurality of electrodes 110 and a separator 120.

[0121] The laminate 100 may be formed by alternately laminating a plurality of electrodes 110 and the separator 120 in the first direction. That is, the plurality of electrodes 110 and the separator 120 constituting the laminate 100 may be alternately laminated in the first direction (for example, the vertical direction). Further, the laminate 100 may be formed by alternately aligning and laminating a plurality of electrodes 110 and the separator 120 in the first direction. That is, the plurality of electrodes 110 and the separator 120 constituting the laminate 100 may be aligned and laminated.

[0122] On the other hand, the laminate 100 may be composed of a plurality of unit cells (C). The plurality of unit cells (C) constituting the laminate 100 may be aligned and laminated in the first direction. The unit cell (C) may have, for example, two types, a monocell (C1) and a half cell (C2) (FIG. 2).

[0123] Each unit cell (C) may be composed of some of the plurality of alternately laminated electrodes 110 and the separator 120 (FIG. 2). For example, the monocell (C1) may be a unit cell (C) in which the separator 120, the electrode 110 (for example, the negative electrode), the separator 120, and the electrode 110 (for example, the positive electrode) are sequentially laminated, and the half cell (C2) may be a unit cell (C) in which the separator 120, the electrode 110 (for example, the negative electrode), and the separator 120 are sequentially laminated.

[0124] The electrode 110 and the separator 120 forming each unit cell (C) may be joined to each other.

[0125] An example of a method for manufacturing a conventional monocell (C1) is as follows.

[0126] While the lower electrode 110 is being moved to one side by a conveyor belt or the like, an upper separation film 120 and a lower separation film 120 are respectively laminated on the upper and lower surfaces (one side surface and the other side surface in the first direction) of the lower electrode 110, and then an upper electrode 110 is further laminated on the uppermost end. Then, a lamination process of applying heat and pressure to the laminated electrodes 110 and separation films 120 is performed. By performing such a lamination process, the electrodes 110 and the separation films 120 are joined to each other, and a monocell (C1) can be firmly formed.

[0127] The method for manufacturing the monocell (C1) can be analogously applied to the method for manufacturing the half cell (C2).

[0128] For example, the half cell (C2) may be laminated on one side in the first direction of the monocell (C1) such that the electrode 110 at one end (for example, the upper end) in the first direction of the monocell (C1) does not directly contact the battery case (not shown). Since the separation film 120 is laminated on both one end and the other end in the first direction, the half cell (C2) may be insulated from the battery case.

[0129] The tape (T) may be attached to the laminate 100. At this time, the tape (T) may be attached while surrounding the laminate 100. The tape (T) can fix the laminate 100 in an aligned state.

[0130] However, when the tape (T) is attached, there is a problem that the separation film 120 is partially bent by the tape (T), and the separation film 120 or the electrode 110 is damaged or a short circuit occurs. Also, in the electrolyte injection process or the gas venting process, the tape (T) may easily fall off the laminate 100, the separation film 120 may be deformed, and a short circuit may occur.

[0131] Therefore, another method for fixing the laminate 100 in an aligned state is required.

[0132] [Electrode Assembly According to an Embodiment of the Present Invention] Referring to FIGS. 4 and 5, the electrode assembly 10 according to an embodiment of the present invention may include a laminate 100 and a wrapping film 200. As described above, when the electrode assembly 10 is housed in a battery case (not shown) and an electrolytic solution is injected into the battery case and then the battery case is sealed, a secondary battery (not shown) can be formed. Hereinafter, the laminate 100 and the wrapping film 200 will be examined.

[0133] The laminate 100 is as described above (FIGS. 1 and 2).

[0134] The wrapping film 200 may surround the laminate 100. The wrapping film 200 can be fused to the laminate 100 to fix the plurality of electrodes 110 and the separator 120 that constitute the laminate 100. Specifically, the wrapping film 200 can fix the plurality of electrodes 110 and the separator 120 in a state where the plurality of electrodes 110 and the separator 120 are aligned.

[0135] Here, "fusing" means melting the base material (wrapping film) itself and joining it to the object (laminate or separator).

[0136] Thereby, since the wrapping film 200 surrounds the laminate 100 and is fused to the laminate 100, the electrodes 110 and the separator 120 can be firmly fixed in an aligned state, and the electrodes 110 and the separator 120 can be protected. For this reason, deformation and breakage of the separator 120, disturbance of the alignment state of the laminate 100, and short circuit due to this can be prevented. In particular, even when a swelling phenomenon occurs in which the electrodes 110 and the like swell after impregnation (wetting) of the electrolytic solution, the wrapping film 200 can fix and protect the laminate 100 without falling off from the laminate 100, so that the separator 120 is not deformed or damaged, the alignment state of the laminate 100 is not disturbed, and no short circuit occurs.

[0137] In addition, since the electrode 110 and the separation membrane 120 can be firmly fixed in an aligned state by the wrapping film 200, it is possible to prevent the laminate 100 from bending when transporting the electrode assembly 10. Therefore, it is possible to prevent deformation and breakage of the separation membrane 120 and disturbance of the alignment state of the laminate 100.

[0138] Fusion bonding can be performed by a thermal compression bonding method, an ultrasonic method, or the like. Among these methods, the wrapping film 200 may be fusion-bonded to the laminate 100 by a thermal compression bonding method.

[0139] Thereby, the wrapping film 200 may be easily fusion-bonded to the laminate 100 with a simple configuration and a low cost.

[0140] The wrapping film 200 can be made of a material including polyethylene terephthalate (PET) and ethylene vinyl acetate (EVA). For example, the wrapping film 200 may be a double film in which an ethylene vinyl acetate (EVA) layer is laminated on a polyethylene terephthalate (PET) layer. These double films may be formed by thermally compressing ethylene vinyl acetate (EVA) onto a polyethylene terephthalate (PET) film or by melt coating an ethylene vinyl acetate (EVA) resin. These double films are widely used for coating films, printing materials, labels, and the like.

[0141] As a result, not only the fixing force and bonding force of the wrapping film 200 are excellent, but also the heat exchange performance of the wrapping film 200 is excellent. For this reason, the electrode 110 and the separation membrane 120 are firmly fixed in an aligned state and can be safely protected. Even when surrounded by the wrapping film 200, the laminate 100 does not overheat, the performance of the secondary battery does not deteriorate, and the lifespan is not shortened. Also, although the wrapping film 200 has excellent insulation performance, since the outermost separation membrane 120 of the laminate 100 can be omitted, the thickness of the electrode assembly 10 can be reduced. In addition, since a commercially available low-cost film can be used as the wrapping film 200, the electrode assembly 10 can be easily manufactured, and the manufacturing cost of the electrode assembly 10 can be reduced.

[0142] The wrapping film 200 may have a bending resistance rigidity greater than that of the separation membrane 120. For example, the wrapping film 200 made of a material containing polyethylene terephthalate (PET) and ethylene vinyl acetate (EVA) may have a greater bending resistance rigidity at the same thickness than the separation membrane 120 made of polyethylene (PE) material.

[0143] As a result, the wrapping film 200 can firmly and correctly fix the electrode 110 and the separation membrane 120 in an aligned state.

[0144] On the other hand, the wrapping film 200 made of a material containing polyethylene terephthalate (PET) and ethylene vinyl acetate (EVA) may be less expensive than the separation membrane 120 made of polyethylene (PE) material. Different from the wrapping film 200, the separation membrane 120 cannot be made of a material containing polyethylene terephthalate (PET) and ethylene vinyl acetate (EVA).

[0145] The electrode tabs 112 of the plurality of electrodes 110 may be arranged on one side (e.g., the front side) or the other side (e.g., the rear side) in a second direction (e.g., the front-rear direction) intersecting the first direction (e.g., the vertical direction) of the laminate 100. At this time, the wrapping film 200 may surround one side (e.g., the upper side) and the other side (e.g., the lower side) in the first direction of the laminate 100, and one side (e.g., the left side) and the other side (e.g., the right side) in a third direction (e.g., the left-right direction) intersecting the first and second directions of the laminate 100. Further, the wrapping film 200 may be fused to at least one side and / or the other side in the first direction of the laminate 100.

[0146] Thereby, avoiding the electrode tabs 112 of the electrodes 110, the wrapping film 200 can easily surround the laminate 100, and the wrapping film 200 can be easily fused to the laminate 100. Therefore, the electrode assembly 10 can be easily manufactured, and the manufacturing cost of the electrode assembly 10 can be reduced.

[0147] The wrapping film 200 may be fused to one side and / or the other side in the first direction of the laminate 100 and one side and / or the other side in the third direction of the laminate 100. For example, the wrapping film 200 may be fused to the upper surface and the lower surface of the separator 120 disposed on the upper side (the upper end) and the lower side (the lower end) in the vertical direction (the first direction) of the laminate 100. Further, the wrapping film 200 may be fused to the left side (the left end portion) and the right side (the right end portion) in the left-right direction (the third direction) of the separator 120 of the laminate 100.

[0148] Thereby, the area where the wrapping film 200 is fused to the laminate 100 increases, or the number of separators 120 to which the wrapping film 200 is fused increases, so that the electrodes 110 and the separators 120 can be more firmly fixed in an aligned state. Therefore, deformation and breakage of the separator 120, disturbance of the alignment state of the laminate 100, and short circuit caused thereby can be prevented.

[0149] On one hand, as shown in the drawing, when one side (left side) end and the other side (right side) end of the separation membrane 120 disposed at one end (upper end) of the first direction (vertical direction) of the laminate 100 are bent downward in the first direction, the central portion of the separation membrane 120 in the third direction (left - right direction) at one end (upper end) of the laminate 100 in the first direction (vertical direction) can constitute one side (upper side) of the laminate 100, and one side end and the other side end of the separation membrane 120 in the third direction can constitute one side (left side) and the other side (right side) of the laminate 100 in the third direction.

[0150] Referring further to FIG. 6, the wrapping film 200 may extend in the second direction and surround a portion corresponding to a predetermined section (S, FIG. 6) in the second direction of a plurality of separation membranes 120. Here, the predetermined section (S) may be a section in the second direction extending from the center of the plurality of separation membranes 120 to one side end and the other side end of the separation membrane 120 in the second direction.

[0151] For example, as shown in the drawing, the predetermined section (S) may be a section in the second direction extending from the center of the separation membrane 120 to one end and the other end of the separation membrane 120 in the second direction and including all of the separation membranes 120. However, it is not limited to such a configuration. That is, as another example, the predetermined section (S) may extend from the center of the separation membrane 120 to one side end and the other side end of the separation membrane 120 in a second direction different from the drawing, but extend from one end and the other end of the separation membrane 120 to a point separated inward of the separation membrane 120 by a predetermined distance and include a portion of the separation membrane 120 in the second direction.

[0152] Thereby, the wrapping film 200 can surround the central portion, one side end, and the other side end of a plurality of separation membranes 120 in the second direction at once, but may surround them in a long way in the second direction. For this reason, since the wrapping film 200 can stably surround the laminate 100, the electrodes 110 and the separation membranes 120 can be fixed more firmly in an aligned state. Therefore, deformation and breakage of the separation membrane 120, disturbance of the alignment state of the laminate 100, and short - circuit caused thereby can be prevented.

[0153] The wrapping film 200 fuses to one side end or the other side end in the third direction of at least some of the plurality of separation membranes 120, and may fuse longitudinally in the second direction to a portion (P1 or P2, Fig. 6) corresponding to a predetermined section (S) among one side end or the other side end in the third direction.

[0154] As a result, the area where the wrapping film 200 fuses to the laminate 100 increases, or the number of separation membranes 120 to which the wrapping film 200 fuses increases, so that the electrodes 110 and the separation membranes 120 can be fixed more firmly in an aligned state. Also, since the wrapping film 200 fuses longitudinally in the second direction to the central portion, one side end, and the other side end in the second direction of the separation membranes 120 surrounded by the wrapping film 200 at once, the electrodes 110 and the separation membranes 120 can be fixed more firmly in an aligned state. Therefore, deformation and breakage of the separation membranes 120, disturbance of the alignment state of the laminate 100, and short circuits caused thereby can be prevented.

[0155] The wrapping film 200 may include a first wrapping film 210 and a second wrapping film 220 (Figs. 4 and 5).

[0156] The first wrapping film 210 may be bent to surround at least a part of one side in the first direction, at least a part of one side in the third direction, and at least a part of the other side in the third direction of the laminate 100. The first wrapping film 210 may fuse to at least one side in the first direction of the laminate 100.

[0157] The second wrapping film 220 may be bent to surround at least a part of the other side in the first direction, one side in the third direction, and at least a part of the other side in the third direction of the laminate 100. Both ends of the second wrapping film 220 may overlap with both ends of the first wrapping film 210 in the first direction on one side and the other side in the third direction of the laminate 100. The second wrapping film 220 may be fused to at least the other side in the first direction of the laminate 100 and both ends of the overlapping first wrapping film 210.

[0158] Thus, the laminate 100 is surrounded by the two wrapping films 210 and 220, and the two wrapping films 200 are fused to the laminate 100, so that the electrode assembly 10 can be easily manufactured with a simple structure and at a low cost.

[0159] The first wrapping film 210 may be fused to at least a part of one side in the first direction, one side in the third direction, and at least a part of the other side in the third direction of the laminate 100.

[0160] For example, the first wrapping film 210 may be bent and fused to the separation film 120 disposed at one end (upper end) in the first direction (vertical direction) that constitutes at least a part of one side in the first direction, one side in the third direction, and at least a part of the other side in the third direction of the laminate 100, so that the first wrapping film 210 may be fused to at least a part of one side in the first direction, one side in the third direction, and at least a part of the other side in the third direction of the laminate 100 (FIGS. 4 and 5). Further, the first wrapping film 210 may be fused to one side end (for example, one end) and the other side end (for example, the other end) in the third direction of the laminated separation film 120, so that the first wrapping film 210 may be fused to at least a part of one side (left side) and the other side (right side) in the third direction of the laminate 100 (FIGS. 4 and 5).

[0161] As a result, the area where the first wrapping film 210 fuses to the laminate 100 increases, or the number of separation membranes 120 to which the first wrapping film 210 fuses increases, so that the electrodes 110 and the separation membranes 120 can be fixed more firmly in an aligned state. Therefore, deformation and breakage of the separation membrane 120, disturbance of the alignment state of the laminate 100, and short circuits caused thereby can be prevented.

[0162] Each separation membrane 120 may further extend in one and the other of the third direction beyond the electrodes 110 adjacent to each separation membrane 120 (FIGS. 1 and 2).

[0163] When the wrapping film 200 fuses to the laminate 100, one side end and the other side end of at least a part of the separation membranes 120 in the third direction may bend and become close to or contact the one side end and the other side end of the adjacent separation membranes 120 in the third direction (FIGS. 4 and 5).

[0164] As a result, since the wrapping film 200 surrounds the laminate 100 while pressing the separation membranes 120, the electrodes 110 and the separation membranes 120 can be fixed more firmly in an aligned state. Further, since one side end and the other side end of the separation membrane 120 in the third direction are fixed in a bent state, the pressure applied to one side and the other side of the laminate 100 in the third direction can be easily absorbed, and one side end and the other side end of the separation membrane 120 in the third direction are arranged close to one side end and the other side end of the adjacent separation membranes 120 in the third direction, so that the strength of one side and the other side of the laminate 100 in the third direction can be increased. Thus, the laminate 100 and the separation membranes 120 can be protected. Therefore, deformation and breakage of the separation membrane 120, disturbance of the alignment state of the laminate 100, and short circuits caused thereby can be prevented. In particular, even when a swelling phenomenon occurs in which the electrodes 110 and the like swell after impregnation (wetting) of the electrolytic solution, the separation membrane 120 does not deform or break, the alignment state of the laminate 100 is not disturbed, and no short circuit occurs. Further, it is possible to prevent the laminate 100 from bending when the electrode assembly 10 is transferred. Therefore, deformation and breakage of the separation membrane 120 and disturbance of the alignment state of the laminate 100 can be prevented.

[0165] Also, even if the alignment state of the laminate 100 is disrupted, the electrodes 110 (for example, a pair of electrodes disposed on one side and the other side in the first direction of the separation membrane) are separated from one end portion or the other end portion on the bent third direction side of the separation membrane 120, and the possibility of being directly electrically connected to the battery case can be greatly reduced. Therefore, short circuit can be prevented.

[0166] As described above, the wrapping film 200 may extend in the second direction and surround a portion corresponding to a predetermined section (S) of the plurality of separation membranes 120. Here, the predetermined section (S) may be a section in the second direction that extends from the center to one end portion and the other end portion of the plurality of separation membranes 120 in the second direction, as described above.

[0167] In such a case, when the wrapping film 200 is fused to the laminate 100, at least a first portion (P1) belonging to at least the predetermined section (S) among one end portions on the third direction side of at least some of the separation membranes 120 may be bent and come close to or contact the adjacent separation membranes 120, and at least a second portion (P2) belonging to at least the predetermined section (S) among the other end portions on the third direction side of at least some of the separation membranes 120 may be bent and come close to or contact the adjacent separation membranes 120 (FIGS. 4, 5, 6).

[0168] As a result, while the wrapping film 200 surrounds the laminate 100 while pressing the separation membrane 120, since the central portion, one side end portion, and the other side end portion of the separation membrane 120 in the second direction are surrounded long in the second direction at once, the electrode 110 and the separation membrane 120 can be fixed more firmly in an aligned state. Also, although one side end portion and the other side end portion of the separation membrane 120 in the third direction are fixed in a bent state, since the central portion, one side end portion, and the other side end portion of one side end portion and the other side end portion of the separation membrane 120 in the third direction are bent long in the second direction at once, the pressure applied to one side and the other side in the third direction of the laminate 100 can be easily absorbed. Further, although one side end portion and the other side end portion of the separation membrane 120 in the third direction are arranged close to one side end portion and the other side end portion of the adjacent separation membrane 120 in the third direction, since the central portion, one side end portion, and the other side end portion of one side end portion and the other side end portion of the separation membrane 120 in the third direction are arranged close long in the second direction at once, the strength on one side and the other side in the third direction can be increased. Thus, the separation membrane 120 can be protected. For this reason, deformation and breakage of the separation membrane 120, disturbance of the alignment state of the laminate 100, and short circuit due to this can be prevented.

[0169] Also, even if the alignment state of the laminate 100 is disturbed, the electrodes 110 (for example, a pair of electrodes arranged on one side and the other side in the first direction of the separation membrane) are separated by the bent one side end portion or the other side end portion of the separation membrane 120 in the third direction, but since they are separated long in the second direction by the central portion, one side end portion, and the other side end portion of the bent one side end portion or the other side end portion of the separation membrane 120 in the third direction, the possibility of being directly electrically connected to the battery case can be greatly reduced. For this reason, a short circuit can be prevented.

[0170] When the wrapping film 200 is fused to the laminate 100, one side end portion or the other side end portion of the plurality of separation membranes 120 continuously laminated in the first direction via the electrode 110 may all be bent either in one direction in the first direction or in the other direction in the first direction.

[0171] For example, as shown in FIG. 5, one end and the other end of the upper seven separation membranes 120 continuously laminated in the first direction via the electrode 110 may both be bent in the other direction (downward) of the first direction.

[0172] Thereby, the wrapping film 200 surrounds the laminate 100 while pressing the plurality of separation membranes 120 continuously laminated in a similar direction, so that the electrode 110 and the separation membrane 120 can be more firmly fixed in an aligned state. In addition, one end or the other end of the plurality of separation membranes 120 continuously laminated in the third direction can be densified in the third direction, so that the strength of one side and the other side of the laminate 100 in the third direction can be increased. Therefore, the laminate 100 and the separation membrane 120 can be protected. For this reason, deformation and breakage of the separation membrane 120, disturbance of the alignment state of the laminate 100, and short circuit caused thereby can be prevented.

[0173] On the other hand, the laminate 100 may be composed of a plurality of unit cells (C) laminated in the first direction in an aligned manner (FIGS. 2, 5, 7). Each unit cell (C) may be composed of some of the electrodes 110 and the separation membranes 120 that are alternately laminated to form the laminate 100. The electrodes 110 and the separation membranes 120 forming each unit cell (C) may be joined to each other. Specific matters regarding the unit cell (C) are as described above.

[0174] The wrapping film 200 can surround the laminate 100, fuse to the laminate 100, and fix the plurality of unit cells (C).

[0175] Thereby, since the electrodes 110 and the separation membranes 120 of each of the plurality of unit cells (C) constituting the laminate 100 surrounded and fused by the wrapping film 200 are joined to each other in advance, the electrodes 110 and the separation membranes 120 can be more firmly fixed in an aligned state, and the electrodes 110 and the separation membranes 120 can be safely protected. For this reason, deformation and breakage of the separation membrane 120, disturbance of the alignment state of the laminate 100, and short circuit caused thereby can be prevented.

[0176] [Electrode Assembly According to Another Embodiment of the Present Invention] Referring to FIG. 7, an electrode 110 may be located at one end or the other end of the laminate 100 of the electrode assembly 10 in the first direction according to another embodiment of the present invention.

[0177] For example, unlike FIG. 5, a separation membrane 120 may not be located at one end of the laminate 100 in the first direction in FIG. 7, and an electrode 110 may be located. Considering based on the unit cell (C), unlike FIG. 5, a half cell (C2) may not be located at one end of the laminate 100 in the first direction in FIG. 7, and a modified cell (C3) in which a separation membrane 120 and an electrode 110 (for example, a negative electrode) are sequentially laminated may be located. That is, the separation membrane 120 at one end or the other end of the laminate 100 in the first direction can be omitted.

[0178] The wrapping film 200 may be fused to one side or the other side in the first direction of the electrode 110 located at one end or the other end of the laminate 100 in the first direction.

[0179] Thereby, in order to insulate the electrode 110 located on the outermost contour of the laminate 100 in the first direction from a battery case (not shown), the separation membrane 120 located at one end or the other end of the laminate 100 in the first direction can be replaced with the wrapping film 200. For this reason, since the thickness of the electrode assembly 10 can be reduced, the energy density of the secondary battery including the electrode assembly 10 can be increased.

[0180] [Method for Manufacturing Electrode Assembly] Referring to FIG. 9, a method (S500) for manufacturing an electrode assembly according to an embodiment may include a lamination step (S510) and a wrapping step (S520).

[0181] In the lamination step (S510), the laminate 100 can be formed. For example, a plurality of electrodes 110 and separation membranes 120 can be alternately laminated in the first direction. At this time, a plurality of electrodes 110 and separation membranes 120 can be laminated while being aligned.

[0182] Specifically, for example, a plurality of unit cells (C) in which the electrode 110 and the separation membrane 120 are alternately laminated in the first direction can be laminated while being aligned. At this time, as described above, the electrode 110 and the separation membrane 120 forming each unit cell (C) may be joined to each other in advance. Referring to FIG. 8, in the wrapping step (S520, a to k in FIG. 9), the laminate 100 can be surrounded by the wrapping film 200 and the wrapping film 200 can be fused to the laminate 100. Specifically, the wrapping film 200 can surround one side and the other side of the laminate 100 in the first direction and one side and the other side of the laminate 100 in the third direction, and the wrapping film 200 can be fused to at least one side or the other side of the laminate 100 in the first direction.

[0183] Thereby, the electrode 110 and the separation membrane 120 can be firmly fixed in an aligned state, and the electrode assembly 10 that can protect the electrode 110 and the separation membrane 120 can be manufactured. For this reason, deformation and breakage of the separation membrane 120, disturbance of the alignment state of the laminate 100, and short circuit due to this can be prevented.

[0184] As described above, the wrapping film 200 may include a first wrapping film 210 and a second wrapping film 220.

[0185] The wrapping step (S520) may include a first wrapping step (S522, a to e in FIG. 9) and a second wrapping step (S524, f to k in FIG. 9).

[0186] In the first wrapping step (S522, a to e in FIG. 9), the first wrapping film 210 can be fused to at least a part of one side in the first direction, at least a part of one side in the third direction, and at least a part of the other side in the third direction of the laminate 100.

[0187] Specifically, for example, as shown in FIGS. 9(a), 9(b), and 9(d), the first wrapping film 210 can be disposed on one side of the laminate 100 in the first direction, and the first wrapping film 210 can be fused to one side of the laminate 100 in the first direction. Also, as shown in FIG. 9(c), the first wrapping film 210 can be disposed on one side of the laminate 100 in the third direction, and the first wrapping film 210 can be fused to one side of the laminate 100 in the third direction. Further, as shown in FIG. 9(e), the first wrapping film 210 can be disposed on the other side of the laminate 100 in the third direction, and the first wrapping film 210 can be fused to the other side of the laminate 100 in the third direction.

[0188] In the second wrapping step (S524, FIGS. 9(f) to 9(k)), as shown in FIG. 9(f), after turning over the laminate 100 such that one side and the other side change with each other in the first direction, the second wrapping film 220 is fused to one side of the laminate 100 in the first direction, and on one side and the other side of the laminate 100 in the third direction, the second wrapping film 220 can be fused to at least both ends of the first wrapping film 210.

[0189] Specifically, for example, as shown in FIGS. 9(g), 9(h), and 9(j), the second wrapping film 220 is disposed on one side of the laminate 100 in the first direction (the other side of the laminate in the first direction before turning the laminate over), and the second wrapping film 220 can be fused to one side of the laminate 100 in the first direction. Also, as shown in FIG. 9(i), although the second wrapping film 220 is disposed on one side of the laminate 100 in the third direction, it is superimposed on the end portion of the first wrapping film 210 in the first direction, and the second wrapping film 220 can be fused to at least the first wrapping film 210. At this time, the second wrapping film 220 can also be fused to a portion of one side of the laminate 100 in the third direction where the first wrapping film 210 is not fused. Further, as shown in FIG. 9(k), although the second wrapping film 220 is disposed on the other side of the laminate 100 in the third direction, it is superimposed on the end portion of the first wrapping film 210 in the first direction, and the second wrapping film 220 can be fused to at least the first wrapping film 210. At this time, the second wrapping film 220 can also be fused to a portion of the other side of the laminate 100 in the third direction where the first wrapping film 210 is not fused.

[0190] Thus, the laminate 100 can be surrounded and fused to the laminate 100 using both wrapping films 210 and 220. At this time, the first wrapping step (S522, FIGS. 9(a) to 9(e)) of fusing the first wrapping film 210 and the second wrapping step (S524, FIGS. 9(f) to 9(k)) of fusing the second wrapping film 220 can correspond to each other sequentially except for the step (f) of turning the laminate 100 over. Therefore, since the manufacturing process of the electrode assembly 10 is simplified, the manufacturing equipment for the electrode assembly 10 is simplified, and the manufacturing cost of the electrode assembly 10 can be reduced.

[0191] In the wrapping step (S520), a wrapping film 200 is placed on one side of the laminate 100 in the first direction (a, g). After a predetermined portion of the wrapping film 200 placed on one side of the laminate 100 in the first direction is pressed and fixed with a fixing member (Z) (b, d, h, j), while moving the roller (R) in the third direction on one side of the laminate 100 in the first direction, the wrapping film 200 is pressed to thermally bond the wrapping film 200 to one side of the laminate 100 in the first direction by a thermal compression bonding method (b, d, h, j). On one side and the other side of the laminate 100 in the third direction, while moving the roller (R) in the first direction, the wrapping film 200 is pressed to thermally bond the wrapping film 200 to at least a part of one side and at least a part of the other side of the laminate 100 in the third direction (c, e).

[0192] Accordingly, when the wrapping film 200 is fixed to one side of the laminate 100 in the first direction with the fixing member (Z), the wrapping film 200 can be thermally bonded to one side of the laminate 100 in the first direction, one side in the third direction, and the other side in the third direction by a thermal compression bonding method. Therefore, when the wrapping film 200 is bonded to the laminate 100, the alignment state of the laminate 100 laminated in the first direction can be easily maintained, and the wrapping film 200 can be bonded to one side of the laminate 100 in the first direction, one side in the third direction, and the other side in the third direction with a minimum fixing operation. Thus, since the manufacturing process of the electrode assembly 10 is simplified, the manufacturing equipment of the electrode assembly 10 is simplified, the manufacturing cost of the electrode assembly 10 can be reduced, and the manufacturing time can be shortened.

[0193] Further, in order to press the wrapping film 200 while moving the roller (R) in the first direction to bond the wrapping film 200 to one side and the other side of the laminate 100 in the third direction, while the wrapping film 200 is being bonded, the one-side end and the other-side end of the separator 120 may naturally bend and come close to or contact the one-side end and the other-side end of the adjacent separator 120 in the third direction. Therefore, as described above, deformation and breakage of the separator 120, disturbance of the alignment state of the laminate 100, and short circuit caused thereby can be prevented.

[0194] On the other hand, in the wrapping step (S520), after a predetermined portion of the wrapping film 200 placed on one side in the first direction of the laminate 100 is pressed and fixed by the fixing member (Z) (h, j), on one side and the other side in the third direction of the laminate 100, while moving the roller (R) in the first direction, the wrapping film 200 is pressed so that the wrapping film 200 can be heat-sealed to the wrapping film 200 already fused to one side and the other side in the third direction of the laminate 100 by a heat-pressing method (i, k). For example, as described above, the second wrapping film 220 can be fused to the first wrapping film 210.

[0195] As a result, the laminate 100 can be firmly and easily surrounded by the wrapping film 200.

[0196] In the wrapping step (S520), the process of heating the wrapping film 200 may be involved. For example, after the roller (R) is heated, the heated roller (R) can heat and press the wrapping film 200. For this reason, the wrapping film 200 can be heat-pressed (heat-fused) to the laminate 100.

[0197] In the wrapping step (S520), the wrapping film 200 may be fused to the laminate 100 while being heated to the first temperature. The first temperature may be higher than the second temperature at which the separation film 120 is heated so that the separation film 120 is joined (for example, laminated) to the electrode 110.

[0198] Thus, when the wrapping film 200 fuses to the separation film 120 of the laminate 100, the separation film 120 can also fuse to the wrapping film 200 and / or the electrode 110. Therefore, even if the wrapping film 200 is strongly bonded to the laminate 100, the wrapping film 200 can fix and protect the laminate 100 without falling off the laminate 100. For this reason, the separation film 120 is not deformed or damaged, the alignment state of the laminate 100 is not disturbed, and no short circuit occurs. Here, the first temperature may be greater than or the same as 110 degrees Celsius and may be less than 160 degrees Celsius, and the second temperature may be greater than or the same as 80 degrees Celsius and may be less than 110 degrees Celsius. For example, the first temperature may be approximately 120 degrees Celsius or more and 140 degrees Celsius or less, and the second temperature may be approximately 100 degrees Celsius.

[0199] Thus, the wrapping film 200 can fix and protect the laminate 100 without falling off the laminate 100. For this reason, the separation film 120 is not deformed or damaged, the alignment state of the laminate 100 is not disturbed, and no short circuit occurs.

[0200] It should be understood that the foregoing embodiments are illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims set forth below rather than the foregoing detailed description. And, of course, all changes and modifications that can be conceived from the equivalent concepts of the meaning and scope of the claims set forth below are construed as being included within the scope of the present invention.

[0201] As described above, the present invention has been described with reference to the exemplary drawings. However, the present invention is not limited by the embodiments and drawings disclosed herein, and it is obvious that various modifications can be made by those of ordinary skill in the art within the scope of the technical idea of the present invention. Further, even if the effects of the configuration of the present invention are not explicitly described while describing the embodiments of the present invention, it is natural that the effects predictable by the configuration should also be recognized.

Explanation of Reference Numerals

[0202] 10 Electrode assembly 100 Laminate 110 Electrode 112 Electrode tab 120 Separation membrane 200 Wrapping film 210 First wrapping film 220 Second wrapping film C Unit cell

Claims

1. A laminate formed by alternately laminating a plurality of electrodes and separation membranes in a first direction, and a wrapping film that surrounds the laminate, fuses to the laminate, and fixes the plurality of electrodes and separation membranes, and electrode tabs of the plurality of electrodes are disposed on one side or the other side in a second direction intersecting the first direction of the laminate, and the wrapping film surrounds one side and the other side in the first direction of the laminate and one side and the other side in a third direction intersecting the first and second directions of the laminate, and fuses to at least one side or the other side in the first direction of the laminate, an electrode assembly.

2. The wrapping film fuses to one side or the other side in the first direction of the laminate and one side or the other side in the third direction of the laminate, The electrode assembly according to claim 1.

3. The wrapping film includes a first wrapping film and a second wrapping film, and the first wrapping film is bent to surround at least a part of one side in the first direction, at least a part of one side in the third direction, and at least a part of the other side in the third direction of the laminate, and fuses to at least one side in the first direction of the laminate, and the second wrapping film is bent to surround at least a part of the other side in the first direction, at least a part of one side in the third direction, and at least a part of the other side in the third direction of the laminate, both ends of which are on one side and the other side in the third direction of the laminate, overlap both ends of the first wrapping film in the first direction, and fuse to at least the other side in the first direction of the laminate and both ends of the overlapping first wrapping film, The electrode assembly according to claim 1.

4. The first wrapping film fuses to at least a part of one side in the first direction, at least a part of one side in the third direction, and at least a part of the other side in the third direction of the laminate, The electrode assembly according to claim 3.

5. Each of the separation membranes extends further in one and the other directions in the third direction than the electrode adjacent to each of the separation membranes, and when the wrapping film fuses to the laminate, one side end and the other side end in the third direction of at least a part of the separation membranes are bent to be close to or in contact with one side end and the other side end in the third direction of the adjacent separation membranes, The electrode assembly according to claim 1.

6. Each of the separation membranes extends further in one and the other directions in the third direction than the electrode adjacent to each of the separation membranes, When the wrapping film is fused to the laminate, one end or the other end in the third direction of the plurality of separation membranes continuously laminated in the first direction via the electrode is bent either in one direction of the first direction or in the other direction of the first direction. The electrode assembly according to claim 1.

7. The wrapping film extends in the second direction and surrounds a portion corresponding to a predetermined section (S) in the second direction of the plurality of separation membranes. The predetermined section (S) is a section in the second direction that extends from the center of the plurality of separation membranes to one end and the other end in the second direction. The electrode assembly according to claim 1.

8. The wrapping film is fused to one end or the other end in the third direction of at least some of the plurality of separation membranes, but is fused long in the second direction to a portion corresponding to the predetermined section (S) among one end or the other end in the third direction. The electrode assembly according to claim 7.

9. When the wrapping film is fused to the laminate, at least a first part belonging to at least the predetermined section among one ends in the third direction of at least some of the separation membranes is bent to get close to or contact the adjacent separation membranes, and at least a second part belonging to at least the predetermined section among the other ends in the third direction of at least some of the separation membranes is bent to get close to or contact the adjacent separation membranes. The electrode assembly according to claim 7.

10. The electrode is located at one end or the other end of the laminate in the first direction. The wrapping film is fused to one side or the other side in the first direction of the electrode located at one end or the other end of the laminate in the first direction. The electrode assembly according to claim 1.

11. The laminate is composed of a plurality of unit cells laminated in the first direction in alignment. Each of the unit cells is composed of some of the plurality of electrodes and separation membranes laminated alternately. The electrode and the separation membrane forming each of the unit cells are joined to each other. The wrapping film surrounds the laminate, is fused to the laminate, and fixes the plurality of unit cells. The electrode assembly according to claim 1.

12. The fusion is performed by a thermocompression bonding method. The electrode assembly according to claim 1.

13. The wrapping film is made of a material containing polyethylene terephthalate (PET) and ethylene vinyl acetate (EVA). The electrode assembly according to claim 1.

14. The wrapping film has a greater bending resistance rigidity than the separation membrane. The electrode assembly according to claim 1.

15. In the method for manufacturing an electrode assembly according to any one of claims 1 to 14, a lamination step of forming the laminate, a wrapping step of surrounding one side and the other side of the laminate in the first direction and one side and the other side of the laminate in the third direction with the wrapping film, and fusing the wrapping film to at least one side or the other side of the laminate in the first direction, A method for manufacturing an electrode assembly.

16. The wrapping film includes a first wrapping film and a second wrapping film, The wrapping step includes a first wrapping step of fusing the first wrapping film to at least a part of one side in the first direction, at least a part of one side in the third direction, and at least a part of the other side in the third direction of the laminate, a second wrapping step of turning over the laminate so that one side and the other side change with each other in the first direction, then fusing the second wrapping film to one side of the laminate in the first direction, and fusing the second wrapping film to at least both ends of the first wrapping film on one side and the other side of the laminate in the third direction, The method for manufacturing an electrode assembly according to claim 15.

17. In the wrapping step, the wrapping film is placed on one side of the laminate in the first direction, a predetermined portion of the wrapping film placed on one side of the laminate in the first direction is pressed and fixed with a fixing member, and then, on one side of the laminate in the first direction, the wrapping film is pressed while moving a roller in the third direction to fuse the wrapping film to one side of the laminate in the first direction by a thermocompression bonding method, and on one side and the other side of the laminate in the third direction, the wrapping film is pressed while moving the roller in the first direction to fuse the wrapping film to at least a part of one side of the laminate in the third direction and at least a part of the other side of the laminate in the third direction by a thermocompression bonding method. The method for manufacturing an electrode assembly according to claim 15.

18. In the wrapping step, the wrapping film is placed on one side of the laminate in the first direction, and after a predetermined portion of the wrapping film placed on one side of the laminate in the first direction is pressed and fixed with a fixing member, the wrapping film is pressed while moving a roller in the first direction on one side and the other side of the laminate in the third direction, and the wrapping film is heat-sealed to the wrapping film already fused to one side and the other side of the laminate in the third direction by a heat-sealing method. The method for manufacturing an electrode assembly according to claim 15.

19. In the wrapping step, the wrapping film is fused to the laminate while being heated to a first temperature. The first temperature is higher than a second temperature at which the separation membrane is heated so that the separation membrane is joined to the electrode. The method for manufacturing an electrode assembly according to claim 15.

20. The first temperature is greater than or equal to 110 degrees Celsius and less than 160 degrees Celsius. The second temperature is greater than or equal to 80 degrees Celsius and less than 110 degrees Celsius. The method for manufacturing an electrode assembly according to claim 19.

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