Electrode assembly and secondary battery including the same

Abstract

According to one embodiment of the present invention, an electrode assembly includes an electrode assembly in which electrodes and separators are alternately stacked, the electrode assembly including a first adhesive portion formed between the electrode and the separator in a direction in which the electrodes and the separator are stacked, and a second adhesive portion formed between adjacent separators among a plurality of separators included in the electrode assembly in a direction in which the electrodes and the separator are stacked, the second adhesive portion being located outside the first adhesive portion in a direction perpendicular to the direction in which the electrodes and the separator are stacked.

Description

Technical Field

[0001] [Cross - reference to Related Applications] This application claims the benefit of priority based on Korean Patent Application No. 10 - 2022 - 0005740, filed on January 14, 2022, and all the contents disclosed in the literature of the Korean patent application are incorporated herein by reference.

[0002] The present invention relates to an electrode assembly and a secondary battery including the same, and more particularly, to an electrode assembly and a secondary battery including the same that prevent process defect rates and battery performance degradation.

Background Art

[0003] Generally, types of secondary batteries include nickel - cadmium batteries, nickel - metal hydride batteries, lithium - ion batteries, and lithium - ion polymer batteries. Such secondary batteries are used not only in small products such as digital cameras, P - DVDs, MP3Ps, mobile phones, PDAs (registered trademark), Portable Game Devices, Power Tools, and E - bikes, but also in large products that require high power such as electric vehicles and hybrid vehicles, as well as in power storage devices for storing surplus generated power and new renewable energy and backup power storage devices.

[0004] To manufacture such 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 and a negative electrode, and these are laminated on both sides of a separator to form an electrode assembly of a predetermined shape. Then, the electrode assembly is housed in a battery case and sealed after injecting an electrolyte.

[0005] Electrode assemblies are classified into various types. For example, a simple stack type that simply continues to stack the positive electrode, separator membrane, and negative electrode in an intersecting manner without manufacturing unit cells; a lamination and stack type (L&S) that first manufactures unit cells using the positive electrode, separator membrane, and negative electrode and then stacks such unit cells; a stack and folding type (S&F) in which a plurality of electrodes or unit cells are attached to one side of a separator membrane sheet that is long on one side at intervals and the separator membrane sheet is repeatedly folded in the same direction from one end; a Z-folding type in which a plurality of electrodes or unit cells are alternately attached to one side and the other side of a separator membrane sheet that is long on one side, the separator membrane sheet is folded in a specific direction from one end, and then the folding in the opposite direction is alternately repeated.

[0006] Among these, in order to manufacture a lamination and stack type, stack and folding type, or Z-folding type electrode assembly, unit cells can be manufactured first. Generally, in order to manufacture unit cells, separator membranes can be laminated on the upper and lower surfaces of a central electrode, and then an upper electrode can be further laminated on the uppermost end. And a lamination process of applying heat and pressure to the laminate in which the electrodes and separator membranes are laminated can be performed. By performing such a lamination process, the electrodes and the separator membranes can be adhered to each other and unit cells can be firmly formed.

[0007] However, conventionally, before performing the lamination process on the laminate in which the electrode and the separation membrane are laminated, the electrode and the separation membrane were not adhered to each other but merely in contact. Therefore, there was a problem that the electrode detached from the correct position during the process of transferring the laminate in order to perform the lamination process. In addition, since the lamination process involves applying high heat and pressure to the laminate, there could also be a problem of electrode damage. Furthermore, in recent years, a separation membrane that can adhere to the electrode even with low heat and pressure has been developed, but such a separation membrane has an excessive manufacturing cost and consumes a large amount, is not economical, and also has a problem of reducing the process efficiency.

[0008] On the other hand, as a method for solving such problems, a method of manufacturing a unit cell using an adhesive can be considered. However, in this case, since the adhesive exists on the electrode surface and the electrode cannot exert its own function at that part, there is a problem of reduced battery performance.

Summary of the Invention

Problems to be Solved by the Invention

[0009] The problem to be solved by the present invention is to provide an electrode assembly that prevents the electrode or the separation membrane from detaching from the correct position when manufacturing a unit cell by laminating the electrode and the separation membrane, and a secondary battery including the same.

[0010] In addition, compared with the conventional method of manufacturing a basic unit cell by lamination, it is possible to reduce the production cost, prevent the deterioration of battery performance while reducing the process defect rate caused by high heat and pressure, and provide an electrode assembly and a secondary battery including the same.

[0011] However, the problems to be solved by the embodiments of the present invention are not limited to the above-mentioned problems, and can be variously extended within the scope of the technical idea included in the present invention.

Means for Solving the Problems

[0012] According to an embodiment of the present invention, an electrode assembly in which electrodes and a separation membrane are alternately laminated includes a first adhesive portion formed between the electrode and the separation membrane, and a second adhesive portion formed between adjacent separation membranes among a plurality of separation membranes included in the electrode assembly. The second adhesive portion is located outside the first adhesive portion.

[0013] The first adhesive for forming the first adhesive portion and the second adhesive for forming the second adhesive portion may be of different types from each other.

[0014] The first adhesive can have a property of being dissolved in an electrolytic solution.

[0015] The second adhesive can have a property of not being dissolved in an electrolytic solution.

[0016] The first adhesive portion can include an adhesive pattern arranged at the same position for each between the electrode and the separation membrane.

[0017] The first adhesive portion can include an adhesive pattern arranged in a form intersecting with each other for each between the electrode and the separation membrane.

[0018] The separation membrane can have no binder coated on its surface or a binder content coated on the surface of 3 wt% or less.

[0019] The electrode assembly further includes an electrode tab protruding from one end of the electrode, and the outside of the first adhesive portion can be located in a direction intersecting with the direction in which the electrode tab protrudes.

[0020] The second adhesive portion can be located between the electrode tab and the separation membrane.

[0021] At least one of the first adhesive portion and the second adhesive portion can be formed by applying an adhesive in a dot shape.

[0022] The first bonding portion can be formed by applying an adhesive in a dot shape.

[0023] The second bonding portion can be formed of an adhesive layer having a plurality of openings.

[0024] The adhesive layer forming the second bonding portion can be formed by partially applying an adhesive along the entire length direction of the electrode assembly.

[0025] The electrode assembly further includes an electrode tab protruding from one end of the electrode, and the entire length direction can be the same as the direction in which the electrode tab protrudes.

[0026] The second bonding portion can connect the extension portions of the separation film extending from the periphery corresponding to the long side of the electrode to each other.

[0027] The second bonding portion can connect the extension portions of the separation film extending from the periphery corresponding to the long side of the electrode to each other.

[0028] The separation film can have a zigzag shape formed by folding a rectangular separation film sheet.

[0029] A finished separation film can be located outside the second bonding portion.

[0030] The separation film has opposite long sides and opposite short sides, and the adhesive layer forming the second bonding portion can be formed along the long side of the separation film.

[0031] The electrode includes a positive electrode and a negative electrode, and the end portion of the positive electrode may not be able to contact the adhesive layer forming the second bonding portion.

[0032] The adhesive layer forming the second bonding portion can have a pattern shape in which at least two lines intersect.

[0033] A secondary battery according to another embodiment of the present invention includes an electrode assembly in which electrodes and a separator are alternately stacked; and a pouch case that houses both the electrode assembly and an electrolytic solution. At least one adhesive coating mark remains on a surface of the separator that contacts the electrode, and an adhesive portion is formed between adjacent separators among a plurality of separators included in the electrode assembly.

[0034] The adhesive coating mark may be a trace of a first adhesive layer formed between the electrode and the separator being dissolved in the electrolytic solution.

[0035] The adhesive layer is formed by applying an adhesive in a plurality of dot shapes, and the adhesive coating mark can be formed in a dot shape at a position where the adhesive layer is formed.

[0036] The adhesive is an acrylate-based adhesive, and the electrolytic solution can be an organic solvent.

[0037] The electrode includes a first electrode and a second electrode, the separator includes an upper separator and a lower separator, and the electrode assembly can have a structure in which the lower separator, the first electrode, the upper separator, and the second electrode are alternately stacked.

[0038] The electrode includes a first electrode and a second electrode. In the electrode assembly, the first electrode is placed on the separator, one side of the separator is folded to cover the first electrode, the second electrode is placed on the separator, and the other side of the separator is folded to cover the second electrode.

[0039] An electrode tab is formed at one end of the electrode, and a second adhesive layer is formed between the electrode tab and the separator. The second adhesive layer can include an adhesive component that does not dissolve in the electrolytic solution.

[0040] The adhesive layer can be formed by applying an adhesive in a plurality of dot shapes.

[0041] The electrolytic solution can be a Gelyte electrolytic solution.

[0042] The electrolytic solution can contain a fluorine-based, poly-carbonate-based, or silicon-based oligomer.

Advantages of the Invention

[0043] According to this embodiment, when manufacturing an electrode assembly by alternately laminating electrodes and separation membranes, it is possible to prevent the electrodes or separation membranes from detaching from their correct positions by means of an adhesive.

[0044] Also, at least a part of the adhesive dissolves in the electrolytic solution, and an adhesive coating mark is formed on the separation membrane. Since the adhesive coating mark does not contain the components of the adhesive, it is possible to prevent a decrease in the performance of the battery due to the adhesive.

[0045] Also, compared with the conventional method for manufacturing a basic unit cell by lamination, production costs can be reduced, and the defect rate in the process caused by high heat and pressure can be lowered.

Brief Description of the Drawings

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Best Mode for Carrying Out the Invention

[0047] Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement it. However, the present invention can be realized in various different forms and is not limited or restricted by the following embodiments.

[0048] To clearly explain the present invention, detailed descriptions of parts that are unnecessary for explanation or related known technologies that unnecessarily clarify the gist of the present invention are omitted. When adding reference numerals to the components of each drawing in this specification, the same or similar components throughout the specification shall be given the same or similar reference numerals.

[0049] In addition, the sizes and thicknesses of the respective configurations shown in the drawings are arbitrarily shown for the convenience of explanation, and thus the present invention is not necessarily limited to what is shown. The thickness is enlarged to clearly represent a plurality of layers and regions from the drawings. And in the drawings, for the convenience of explanation, the thicknesses of some layers and regions are exaggeratedly shown.

[0050] Also, the terms and words used in this specification and the claims should not be construed as being limited to their ordinary or dictionary meanings. Based on the principle that the inventor can appropriately define the concept of the terms in order to explain his own invention in the best way, they must be construed in meanings and concepts that conform to the technical idea of the present invention.

[0051] Also, throughout the specification, when a certain part "includes" a certain component, this means that, unless otherwise stated to the contrary, it does not exclude other components, but can further include other components.

[0052] FIG. 1 is a flowchart showing a method for manufacturing a secondary battery according to an embodiment of the present invention.

[0053] Referring to FIGS. 1 to 3, a method for manufacturing a secondary battery according to an embodiment of the present invention can include a basic unit manufacturing stage, an electrode assembly manufacturing stage, an initial cell manufacturing stage, and a final cell manufacturing stage.

[0054] Hereinafter, in a method for manufacturing a secondary battery according to an embodiment of the present invention, the basic unit manufacturing stage and the electrode assembly manufacturing stage will be mainly described.

[0055] FIG. 2 is a perspective view showing the manufacturing stage of a basic unit of a secondary battery manufacturing method according to an embodiment of the present invention. FIG. 3 is a front view showing the manufacturing stage of a basic unit of a secondary battery manufacturing method according to an embodiment of the present invention.

[0056] First, in this embodiment, the basic unit 10 can be a laminated unit of an electrode and a separator 13. That is, the electrode and the separator 13 are laminated in order to form one basic unit 10, and when a plurality of the basic units 10 are laminated, it can become the electrode laminate 20 of FIG. 4.

[0057] In the secondary battery manufacturing method according to this embodiment, the basic unit manufacturing stage can be a stage of manufacturing the basic unit 10 in which the adhesive 14 is applied to at least one surface of the electrode and the separator 13 and the electrode and the separator 13 are adhered to each other.

[0058] Referring to FIGS. 2 and 3, the basic unit manufacturing stage can include a stage in which the lower separator sheet 111 is unwound from the lower separator reel 110. And it can include a stage in which the first nozzle 211 applies the adhesive 14 to at least a part of one surface facing upward from the unwound lower separator sheet 111. The first nozzle 211 can apply the adhesive 14 in a plurality of dot shapes. After that, a stage in which the first electrode 11 is placed on one surface of the lower separator sheet 111 to which the adhesive 14 has been applied by the first nozzle 211 can follow. The first electrode 11 can be obtained by cutting the first electrode 11 sheet unwound from the first electrode reel 11-1 by the first cutter 221 to a predetermined size and placing it on one surface of the lower separator sheet 111. The first electrode 11 and the lower separator can be adhered by the adhesive 14 applied by the first nozzle 211.

[0059] And the method for manufacturing a secondary battery according to this embodiment may include a step of unwinding the upper separator sheet 121 from the upper separator reel 120. When the upper separator sheet 121 is unwound, a step of applying the adhesive 14 can be performed on at least a part of one surface of the unwound upper separator sheet 121 that contacts the first electrode 11 by the second nozzle 212. The second nozzle 212 can apply the adhesive 14 in a plurality of dot shapes.

[0060] Referring to FIG. 2, after the second nozzle 212 applies the adhesive 14 to one surface of the upper separator sheet 121, the upper separator sheet 121 can have one surface and the other surface inverted with respect to each other. This is because the adhesive 14 is applied in a form that drops from the upper side to the lower side, but the surface of the upper separator sheet 121 that contacts the first electrode 11 faces downward in order to contact the first electrode 11. Therefore, the state when applying the adhesive 14 and the state when adhering to the first electrode 11 may be in a form where they are inverted vertically.

[0061] When the upper separator sheet 121 is inverted vertically and adhered to the first electrode 11, then, a step of applying the adhesive 14 can be performed on at least a part of the other surface of the upper separator sheet 121 that faces upward. That is, the third nozzle 213 can apply the adhesive 14 to the upper part of the laminate in which the lower separator sheet 111, the first electrode 11, and the upper separator sheet 121 are laminated in order from the lower side to the upper side. In this case, the third nozzle 213 can apply the adhesive 14 in a plurality of dot shapes.

[0062] Then, after the third nozzle 213 applies the adhesive 14 in this way, in the method for manufacturing a secondary battery according to an embodiment of the present invention, the basic unit manufacturing stage may include a stage of placing the second electrode 12 on the other surface of the upper separation film sheet 121 coated with the adhesive 14. The second electrode 12 can be formed by cutting the second electrode 12 sheet unwound from the second electrode reel 12-1 using the second cutter 222. Thereby, a four-layer structure can be formed. That is, after the stage of placing the second electrode 12, a four-layer structure laminate 130 formed by laminating the lower separation film sheet 111, the first electrode 11, the upper separation film sheet 121, and the second electrode 12 in order can be formed.

[0063] As shown in FIG. 3, the method may further include a stage in which pressure nip rolls 230 are respectively disposed on the upper and lower surfaces of the four-layer structure laminate 130 and rotated to apply pressure to the four-layer structure laminate 130. Through the pressure application stage by the pressure nip rolls 230, it is possible to prevent portions from floating up within the four-layer structure laminate 130. Based on this, the electrodes and the separator 13 can be closely adhered.

[0064] As shown in FIGS. 2 and 3, after the stage of applying pressure to the four-layer structure laminate 130, the method may further include a stage of cutting the four-layer structure laminate 130 at regular intervals with a cutter to form the basic unit 10. This can manufacture the basic unit 10 by cutting the upper separation film sheet 121 portion and the lower separation film sheet 111 portion located at the interval portion between the electrodes with the third cutter 223.

[0065] In the method for manufacturing a secondary battery according to this embodiment, according to the basic unit manufacturing stage, when laminating the electrodes and the separator to manufacture a unit cell (i.e., the basic unit), each time the electrodes are placed on the separator sheets (the lower separation film sheet 111, the upper separation film sheet 121), by previously applying the adhesive 14, there is an effect that it is possible to prevent the electrodes from being displaced without using an expensive separator.

[0066] In addition, there is no need to perform a lamination process, and the process defect rate caused by high heat and pressure can be reduced. And since the laminator can be removed, the volume of the unit cell manufacturing apparatus can be decreased, and the manufacturing process can be simplified.

[0067] The separator according to the embodiment described in this specification can be a CCS (Ceramic Coated Separator). Generally, the separator has a reactant film and a coating layer formed on at least one surface of the reactant film. The coating layer can include alumina powder and a binder that aggregates these together. In SRS (Safety Reinforced Separator), a large amount of binder is coated on the surface of the coating layer, while in CCS, the binder may not be coated on the surface of the coating layer, or the binder content distributed on the SRS-contrasted surface may be very low. For example, in the case of the CCS separator according to this embodiment, the binder content coated on the surface of the coating layer of the separator can be approximately 3 wt% or less.

[0068] When the separator is CCS, since the internal electrodes included in the electrode assembly are transferred in an unfixed state, the alignment may be disrupted during transfer. Of course, when the separator is CCS, it can also be fixed with heat and pressure, but the alignment of the internal electrodes may be disrupted even during the process of transferring the laminate of the electrode and the separator to the heat and pressure fixing device. In addition, in order to adhere the electrode and the separator with heat and pressure, there is also the disadvantage that an expensive separator with a high binder content must be used. In contrast, according to this embodiment, it is possible to prevent the alignment of the internal electrodes from being disrupted during transfer and to increase the fixing force.

[0069] When the separator is CCS, the electrolyte according to this embodiment can use a Gelyte electrolyte. The Gelyte electrolyte can include a gel-type electrolyte. As an example, the Gelyte electrolyte can physically bond a liquid solvent inside an oligomer to have characteristics of suppressing volatilization and having almost no fluidity, thereby preventing liquid leakage. The oligomer included in the Gelyte electrolyte according to this embodiment can include a fluorine-based, poly-carbonate-based, or silicon-based one. When using a fluorine-based oligomer, it can enhance flame retardancy, play a role in scavenging oxygen generated during the decomposition of the positive electrode material due to heat generation, and have an effect of suppressing further heat generation. When using a poly-carbonate-based oligomer, it has positive electrode affinity and has a structure similar to that of an organic electrolyte, and the ionic conductivity becomes excellent. Also, when using a silicon-based oligomer, it is advantageous for gas reduction, especially plays a role as an HF scavenger, and can improve the high-temperature storage environment.

[0070] Conventionally, if the electrode and the separator are not adhered by heat and pressure, the adhesive force is weak, the cell rigidity is reduced, and there is a high possibility of safety problems. However, when using a Gelyte electrolyte as in this embodiment, compared with the case of using a liquid electrolyte, the adhesive force can be improved by at least 50% or more. As a result, the cell rigidity becomes approximately 40% or more higher than that in the case of using a liquid electrolyte. Even when laminating the electrode and the separator in the lamination process while using SRS as the separator and comparing with the case of using a liquid electrolyte, the cell rigidity can be improved by approximately 19% or more.

[0071] FIG. 4 is a cross-sectional view showing an electrode assembly 1 formed by laminating basic units 10 manufactured in the basic unit manufacturing stage of a secondary battery manufacturing method according to an embodiment of the present invention. FIG. 5 is a cross-sectional view showing an electrode assembly formed by laminating basic units manufactured in the basic unit manufacturing stage of a secondary battery manufacturing method according to another embodiment of the present invention.

[0072] Referring to FIG. 4, in the method for manufacturing a secondary battery according to this embodiment, the electrode assembly manufacturing stage can be a stage of manufacturing the electrode assembly 1 by attaching the fixing tape 50 to the periphery of the electrode laminate 20 formed by laminating a plurality of basic units 10. Here, the electrode assembly manufacturing stage can be performed separately from the above-described basic unit manufacturing stage, or the above-described basic unit manufacturing stage can be included in the electrode assembly manufacturing stage.

[0073] Within the basic unit 10, the electrodes (the first electrode 11 and the second electrode 12) and the separator 13 are in a state of being adhered to each other by the adhesive 14. Based on this, the electrodes (the first electrode 11 and the second electrode 12) and the separator 13 can maintain the alignment degree by the adhesive force of the adhesive 14. And the stacked basic units 10 and the basic units 10 can have their relative positions fixed by the fixing tape 50 attached to the outside. That is, the stacked alignment state of the basic units 10 can be maintained by the fixing force of the fixing tape 50. For reference, the laminate state before attaching the fixing tape 50 can be named the electrode laminate 20, and the laminate state after attaching the fixing tape 50 can be named the electrode assembly 1.

[0074] Also, in the electrode assembly 1 manufactured in this embodiment, the adhesive 14 may be arranged at the same position between each of the electrodes (the first electrode 11 and the second electrode 12) and the separator 13. As an example, as shown in FIG. 4, in the electrode assembly 1 of this embodiment, the adhesive 14 located between the lower part of the first electrode 11 and the separator 13 and the adhesive 14 located between the upper part of the first electrode 11 and the separator 13 can be arranged on the same vertical line with respect to the bottom surface, and the intervals at which the adhesive 14 is arranged may be the same as each other. This can be similarly explained for the case of the adhesive 14 located between the second electrode 12 and the separator 13.

[0075] Thereby, in the electrode assembly 1 manufactured in this embodiment, the adhesive 14 is arranged at the same position between each of the electrodes (the first electrode 11 and the second electrode 12) and the separator 13, which has the advantage of increasing the process time and efficiency.

[0076] In addition, in the electrode assembly 2 manufactured by the secondary battery manufacturing method according to another embodiment of the present invention, the adhesive 14 is disposed between each of the electrodes (the first electrode 11 and the second electrode 12) and the separator 13, and the adhesives 14 disposed in adjacent layers may be disposed in an intersecting form. As an example, as shown in FIG. 5, in the electrode assembly 2 of the present embodiment, the first adhesive 14-1 located between the lower part of the first electrode 11 and the separator 13 and the second adhesive 14-2 between the upper part of the first electrode 11 and the separator 13 can be disposed so as to intersect each other. At this time, the first adhesive 14-1 and the second adhesive 14-2 can have the same applied interval even though their positions intersect each other. This can be similarly explained for the adhesive 14 located between the second electrode 12 and the separator 13.

[0077] As an example, in the above-described basic unit manufacturing stage, by adjusting at least one of the positions of the first nozzle 211, the second nozzle 212, and the third nozzle 213 shown in FIGS. 2 and 3, the first adhesive 14-1 and the second adhesive 14-2 are disposed so as to intersect each other.

[0078] As another example, in the above-described basic unit manufacturing stage, in addition to the first nozzle 211, the second nozzle 212, and the third nozzle 213, another nozzle is further disposed, and the first adhesive 14-1 and the second adhesive 14-2 can be disposed so as to intersect each other. More specifically, the other nozzle is disposed at a position different from the first nozzle 211, the second nozzle 212, and the third nozzle 213. One of the first adhesive 14-1 and the second adhesive 14-2 is applied from the first nozzle 211, the second nozzle 212, and the third nozzle 213, and the other of the first adhesive 14-1 and the second adhesive 14-2 is applied from the other nozzle, and the first adhesive 14-1 and the second adhesive 14-2 can be disposed so as to intersect each other.

[0079] However, without being limited thereto, the structure in which the first adhesive 14-1 and the second adhesive 14-2 are arranged to cross each other can be manufactured by being applied in various ways.

[0080] Accordingly, in the electrode assembly 2 manufactured in this embodiment, the adhesive 14 is disposed between each of the electrodes (the first electrode 11 and the second electrode 12) and the separator 13, and the adhesives 14 disposed in adjacent layers are arranged in a crossed form, and an increase in the thickness of the electrode assembly 2 due to the adhesive 14 can be minimized. Further, since the adhesives 14 disposed in adjacent layers cross each other, the adhesive 14 can be more easily dissolved in the electrolytic solution included in the initial cell 0 of FIG. 29 described later.

[0081] Hereinafter, in the secondary battery manufacturing method according to another embodiment of the present invention, the basic unit manufacturing step and the electrode assembly manufacturing step will be mainly described.

[0082] FIGS. 6 to 9 are schematic views showing the basic unit manufacturing step of the secondary battery manufacturing method according to another embodiment of the present invention.

[0083] First, in this embodiment, the basic unit 30 of FIG. 9 can be a unit in which the separator 322 is folded to cover the electrode 31, and the electrode 31 and the separator 322 are laminated. That is, in the basic unit 30, one side and the other side of the separator 322 are sequentially folded to cover the electrode 31, and the electrode 31 and the separator 322 can be sequentially laminated. An electrode laminate 40 of FIG. 10 in which such basic units 30 are repeatedly formed a plurality of times can be manufactured.

[0084] Referring to FIGS. 6 to 9, the method for manufacturing a secondary battery according to this embodiment includes a step in which electrode sheets 3111 and 3121 are unwound from electrode reels 311 and 312, and a plurality of electrodes 31 are formed from the electrode sheets 3111 and 3121; a step in which a separator 322 forming a laminate with the electrodes 31 is unwound from a separator reel 321; a step in which the separator 322 is placed on the upper surface of a table 36; and a step in which a nozzle 37 applies an adhesive to at least a part of the separator 322 and the electrodes 31 placed on the table 36. The electrode 31 includes a first electrode 3112 and a second electrode 3122. In this embodiment, what is unwound from the separator reel 321 is referred to as the separator 322. However, as will be described later, it can be regarded that the separator sheet is folded to form a separator in each layer. Therefore, it can also be regarded that the separator sheet is unwound from the separator reel 321.

[0085] More specifically, referring to FIG. 6, in the method for manufacturing a secondary battery according to this embodiment, when the first electrode sheet 3111 is unwound from the first electrode reel 311, a first cutter 331 can cut the first electrode sheet 3111 to form a plurality of first electrodes 3112. Thereafter, when a first transfer device 341 transfers the first electrode 3112, a first header 351 adsorbs the first electrode 3112.

[0086] On the other hand, referring to FIG. 6, when the separator 322 is unwound from the separator reel 321, a first region 3221 of the separator 322 is placed on the upper surface of the table 36. Thereafter, as shown in FIG. 6, the first nozzle 371 can apply an adhesive to at least a part of the first region 3221 of the separator 322. Here, the first nozzle 371 can apply the adhesive in a plurality of dot shapes.

[0087] Thereafter, the table 36 can move toward the first transfer device 341, and the first header 351 that has adsorbed the first electrode 3112 can also move toward the table 36. However, it is not limited thereto, and the table 36 may be fixed. When the first header 351 is positioned above the table 36, as shown in FIG. 6, the first header 351 can place the first electrode 3112 on the first region 3221 of the separator 322 coated with the adhesive.

[0088] However, it is not limited thereto. Different from FIG. 6, the adhesive may not be applied to the first region 3221 of the separator 322, and the adhesive may be pre-applied to the lower part of the first electrode 3112. That is, with the adhesive pre-applied to the lower part of the first electrode 3112, the first electrode 3112 can be placed on the first region 3221 of the separator 322 by the first header 351.

[0089] In addition, the method for manufacturing a secondary battery according to this embodiment further includes a folding step after the adhesive application step. In the folding step, when the first electrode 3112 is placed on the separator 322, one side of the separator 322 is folded to cover the first electrode 3112, and when the second electrode 3122 is placed on the separator 322, the other side of the separator 322 can be folded to cover the second electrode 3122.

[0090] More specifically, referring to FIG. 7, after the first electrode 3112 is placed on the first region 3221, the table 36 moves toward the second transfer device 342 that transfers the second electrode 3122. Then, one side of the separator 322 is folded, and the second region 3222 of the separator 322 can cover the first electrode 3112. Here, before the first electrode 3112 is covered by the second region 3222 of the separator 322, the adhesive may be pre-applied to the upper part of the first electrode 3112 or the second region 3222 of the separator 322 by the first nozzle 371.

[0091] On the one hand, when the second electrode sheet 3121 is unwound from the second electrode reel 312, the second cutter 332 cuts the second electrode sheet 3121, and a plurality of second electrodes 3122 can be formed. Then, when the second transfer device 342 transfers the second electrode 3122, the second header 352 adsorbs the second electrode 3122.

[0092] Also, as shown in FIGS. 7 and 8, when the second region 3222 of the separation membrane 322 covers the first electrode 3112, the second nozzle 372 located above the second region 3222 applies an adhesive to at least a part of the second region 3222 of the separation membrane 322. Here, the second nozzle 372 can apply the adhesive in a plurality of dot shapes.

[0093] Then, referring to FIG. 8, the table 36 can move toward the second transfer device 342, and the second header 352 that has adsorbed the second electrode 3122 can also move toward the table 36. However, it is not limited to this, and the table 36 may be fixed. When the second header 352 is located above the table 36, as shown in FIG. 8, the second header 352 can place the second electrode 3122 on the second region 3222 of the separation membrane 322 to which the adhesive has been applied.

[0094] However, it is not limited to this. Different from FIG. 8, no adhesive is applied to the second region 3222 of the separation membrane 322, and an adhesive can be pre-applied to the lower part of the second electrode 3122. That is, with the adhesive pre-applied to the lower part of the second electrode 3122, the second electrode 3122 can be placed on the second region 3222 of the separation membrane 322 by the second header 352.

[0095] Thereafter, referring to FIG. 9, after the second electrode 3122 is placed on the second region 3222, the table 36 moves toward the first transfer device 341 that transfers the first electrode 3112. However, the present invention is not limited thereto, and the table 36 may be fixed. Hereinafter, the other side of the separation membrane 322 is folded so that the first region 3221 of the separation membrane 322 can cover the second electrode 3122. Here, before the second electrode 3122 is covered by the first region 3221 of the separation membrane 322, an adhesive may be previously applied to the upper part of the second electrode 3122 or the first region 3221 of the separation membrane 322 by the second nozzle 372.

[0096] Then, as shown in FIG. 9, when the first region 3221 covers the second electrode 3122, the first nozzle 371 located above the first region 3221 applies an adhesive to at least a part of the first region 3221 of the separation membrane 322. Here, the first nozzle 371 can apply the adhesive in a plurality of dot shapes.

[0097] That is, by repeating the above process, in the method for manufacturing a secondary battery according to the present embodiment, a basic unit can be manufactured.

[0098] FIG. 10 is a cross-sectional view showing an electrode assembly manufactured by repeatedly forming basic units manufactured in the basic unit manufacturing stage of a method for manufacturing a secondary battery according to another embodiment of the present invention. FIG. 11 is a cross-sectional view showing an electrode assembly manufactured by repeatedly forming basic units manufactured in the basic unit manufacturing stage of a method for manufacturing a secondary battery according to another embodiment of the present invention.

[0099] Referring to FIG. 10, in the method for manufacturing a secondary battery according to this embodiment, in the electrode assembly manufacturing stage, the fixing tape 50 can be attached to the periphery of the electrode laminate 40 formed by repeatedly forming the basic unit body 30 a plurality of times, like the electrode laminate 20 in FIG. 4, to manufacture the electrode assembly 3. Further, unlike the electrode assembly 1 in FIG. 4, the fixing tape 50 may be omitted from the electrode assembly 3 as shown in FIG. 10. Also, instead of the fixing tape 50 in FIG. 4, one end of the separator 322 of the electrode assembly 3 can wrap a part of the outer surface of the electrode laminate 40. Here, the electrode assembly manufacturing stage can be performed separately from the above-described basic unit body manufacturing stage, or the above-described basic unit body manufacturing stage can be included in the electrode assembly manufacturing stage.

[0100] The basic unit body 30 of this embodiment can be in a state where the electrodes (the first electrode 3112 and the second electrode 3122) and the separator 322 are adhered to each other by the adhesive 34, like the basic unit body 10 in FIG. 4. Thereby, the electrodes (the first electrode 3112 and the second electrode 3122) and the separator 322 can maintain the alignment degree by the adhesive force of the adhesive 34.

[0101] In the electrode laminate 40 of this embodiment, the separator 322 covers the upper and lower portions and one side surface of the electrodes (the first electrode 3112 and the second electrode 3122), and the laminated alignment state between the basic unit bodies 30 can be maintained without another fixing tape 50 as shown in FIG. 4. Also, when the fixing tape 50 in FIG. 4 is attached to the outside of the electrode laminate 40 of this embodiment, or when one end of the separator 322 wraps it, the laminated alignment state between the basic unit bodies 30 can be maintained more stably.

[0102] Further, in the electrode assembly 3 manufactured in this embodiment, the adhesive 34 can be disposed at the same position between the electrodes (the first electrode 3112 and the second electrode 3122) and the separator 322. As an example, as shown in FIG. 10, in the electrode assembly 3 of this embodiment, the adhesive 34 located between the lower part of the first electrode 3112 and the separator 322 and the adhesive 34 between the upper part of the first electrode 3112 and the separator 322 can be disposed on the same vertical line with reference to the bottom surface of the first electrode 3112 or the separator 322, and the intervals at which the adhesive 34 is disposed may be the same as each other. This can be similarly explained for the case of the adhesive 34 located between the second electrode 3122 and the separator 322.

[0103] Accordingly, in the electrode assembly 3 manufactured in this embodiment, since the adhesive 34 is disposed at the same position between the electrodes (the first electrode 3112 and the second electrode 3122) and the separator 322, there is an advantage that the process time and efficiency can be increased.

[0104] Further, in the electrode assembly 4 manufactured by the secondary battery manufacturing method according to another embodiment of the present invention, the adhesive 34 is disposed between the electrodes (the first electrode 3112 and the second electrode 3122) and the separator 322, and the adhesives 34 disposed in adjacent layers can be disposed in an intersecting form. As an example, as shown in FIG. 11, in the electrode assembly 4 of this embodiment, the first adhesive 34-1 located between the lower part of the first electrode 3112 and the separator 322 and the second adhesive 34-2 between the upper part of the first electrode 3112 and the separator 322 can be disposed to intersect each other. At this time, the first adhesive 34-1 and the second adhesive 34-2 are only intersecting with each other in position, and the intervals at which they are applied can be the same as each other. This can be similarly explained for the case of the adhesive 34 located between the second electrode 3122 and the separator 322.

[0105] As an example, in the above-described basic unit manufacturing stage, by adjusting the position of at least one of the first nozzle 371 and the second nozzle 372, the first adhesive 34-1 and the second adhesive 34-2 are disposed to intersect each other.

[0106] As another example, in the above-described basic unit manufacturing stage, in addition to the first nozzle 371 and the second nozzle 372, another nozzle can be further arranged, and the first adhesive 34-1 and the second adhesive 34-2 can be arranged to cross each other. More specifically, the other nozzle is arranged at a position different from the first nozzle 371 and the second nozzle 372, one of the first adhesive 34-1 and the second adhesive 34-2 is applied from the first nozzle 371 and the second nozzle 372, and the other one of the first adhesive 34-1 and the second adhesive 34-2 is applied from the other nozzle, and the first adhesive 34-1 and the second adhesive 34-2 can be arranged to cross each other.

[0107] However, not limited thereto, the structure in which the first adhesive 34-1 and the second adhesive 34-2 are arranged to cross each other can be manufactured by being applied in various ways.

[0108] Thereby, in the electrode assembly 4 manufactured in this embodiment, the adhesive 34 is arranged between each of the electrodes (the first electrode 3112, the second electrode 3122) and the separator 322, and the adhesives 34 arranged in adjacent layers are arranged in a crossed form, and an increase in the thickness of the electrode assembly 4 due to the adhesive 34 can be minimized. Further, the adhesives 34 arranged in adjacent layers cross each other, and the adhesive 34 can be more easily dissolved in the electrolytic solution contained in the initial cell 0 of FIG. 29 described later.

[0109] Hereinafter, the above-described basic units 10 and 30 will be mainly described.

[0110] FIGS. 12 and 13 are exploded perspective views of a basic unit manufactured in the basic unit manufacturing stage of a secondary battery manufacturing method according to another embodiment of the present invention.

[0111] Referring to FIG. 12, the basic unit 10 can have a structure in which the separation membrane 13, the first electrode 11, the separation membrane 13, and the second electrode 12 are alternately laminated as described in FIGS. 2 to 5. Here, the separation membrane 13 located below the first electrode 11 is named the lower separation membrane, and the separation membrane 13 located below the second electrode 12 is named the upper separation membrane.

[0112] Also, in the case of the basic unit 30, as described in FIGS. 6 to 11, the separation membrane 322 can have a zigzag shape in which the separation membrane 322 is folded to cover the electrodes (the first electrode 3112 and the second electrode 3122), and the first electrode 3112, the separation membrane 322, and the second electrode 3122 are alternately laminated. However, in FIG. 12, for convenience of explanation, the surface on which the separation membrane 322 is folded is shown omitted.

[0113] In the basic units 10 and 30, first electrode tabs 11t and 3112t can be formed at one end of the first electrodes 11 and 3112, and second electrode tabs 12t and 3122t can be formed at one end of the second electrodes 12 and 3122.

[0114] Here, the first electrodes 11 and 3112 and the second electrodes 12 and 3122 can be arranged such that the first electrode tabs 11t and 3112t and the second electrode tabs 12t and 3122t face in different directions from each other.

[0115] Here, adhesive layers (adhesives 14 and 34) can be formed between the first electrodes 11 and 3112 and the separation membranes 13 and 322 and between the second electrodes 12 and 3122 and the separation membranes 13 and 322. As an example, the adhesive layers (adhesives 14 and 34) can be formed by applying the adhesive in a plurality of dot shapes as shown in FIG. 12. Also, the plurality of dots can be arranged at regular intervals. Further, the adhesive layers (adhesives 14 and 34) can contain an adhesive component that dissolves in the electrolytic solution contained in the initial cell 0 of FIG. 29 described later.

[0116] As a result, in the basic units 10 and 30 of this embodiment, the adhesive layers (adhesives 14 and 34) are arranged in a plurality of dot shapes and can be easily dissolved by the electrolytic solution. Further, the adhesive layers (adhesives 14 and 34) contain an adhesive component that dissolves in the electrolytic solution, and in the final battery cell, the adhesive layers (adhesives 14 and 34) do not remain on the surfaces of the first electrodes 11, 3112 and the second electrodes 12, 3122, and it is possible to prevent a decrease in cell performance due to the adhesive layers (adhesives 14 and 34).

[0117] Referring to FIG. 13, the basic units 10' and 30' can be described almost identically to the basic units 10 and 30 of FIG. 12, and hereinafter, the description will be centered on the adhesive layers (adhesives 14 and 34).

[0118] In the basic units 10' and 30' according to this embodiment, the adhesive layers (adhesives 14 and 34) can include a first adhesive layer 1410, 3410 and a second adhesive layer 1420, 3420. Here, the first adhesive layer 1410, 3410 can be located between the central portions of the first electrodes 11, 3112 and the separator 13, 322, and between the central portions of the second electrodes 12, 3122 and the separator 13, 322.

[0119] As an example, as shown in FIG. 13, the second adhesive layer 1420, 3420 can be located at both ends of the separator 13, 322 adjacent to the first electrode tab 11t, 3112t or the second electrode tab 12t, 3122t. More specifically, the second adhesive layer 1420, 3420 can be located between the first electrode tab 11t, 3112t and the separator 13, 322, and between the second electrode tab 12t, 3122t and the separator 13, 322.

[0120] As another example, different from FIG. 13, the second adhesive layer 1420, 3420 may be formed only at the portion where the first electrode tab 11t, 3112t and the separator 13, 322 face each other between the first electrode tab 11t, 3112t and the separator 13, 322, and may be formed only at the portion where the second electrode tab 12t, 3122t and the separator 13, 322 face each other between the second electrode tab 12t, 3122t and the separator 13, 322.

[0121] At this time, the first adhesive layers 1410 and 3410 and the second adhesive layers 1420 and 3420 can be formed by applying an adhesive in a plurality of dot shapes respectively. The first adhesive layers 1410 and 3410 can be formed of a first adhesive, and the second adhesive layers 1420 and 3420 can be formed of a second adhesive.

[0122] Here, the first adhesive for forming the first adhesive layers 1410 and 3410 can contain an adhesive component that dissolves in the electrolytic solution contained in the initial cell 0 of FIG. 29, which will be described later, like the adhesive layers (adhesives 14 and 34) in FIG. 12. In contrast, the second adhesive for forming the second adhesive layers 1420 and 3420 can contain an adhesive component that does not dissolve in the electrolytic solution.

[0123] As an example, in the above-described basic unit manufacturing stage, by changing the type of adhesive applied from at least one of the nozzles 210 in FIGS. 2 and 3 or at least one of the nozzles 37 in FIGS. 6 to 9 in the manufacturing process, the first adhesive layers 1410 and 3410 and the second adhesive layers 1420 and 3420 can be formed respectively. Specifically, the adhesives for forming the first adhesive layers 1410 and 3410 and the second adhesive layers 1420 and 3420 can be applied through one nozzle or through different nozzles.

[0124] As another example, in the above-described basic unit manufacturing stage, in addition to the nozzles 210 in FIGS. 2 and 3 or the nozzles 37 in FIGS. 6 to 9, another nozzle is further arranged, and the first adhesive layers 1410 and 3410 and the second adhesive layers 1420 and 3420 can be formed respectively. More specifically, the another nozzle is arranged adjacent to both ends of the separation membranes 13 and 322, the first adhesive layers 1410 and 3410 are formed from the nozzles 210 in FIGS. 2 and 3 or the nozzles 37 in FIGS. 6 to 9, and the second adhesive layers 1420 and 3420 can be formed from the another nozzle.

[0125] However, without being limited thereto, the first adhesive layers 1410 and 3410 and the second adhesive layers 1420 and 3420 can be formed by applying different adhesives to each other in various ways.

[0126] Accordingly, in the basic units 10' and 30' of the present embodiment, the first adhesive layers 1410 and 3410 are located between the central portions of the first electrodes 11 and 3112 and the separation membranes 13 and 322, and between the central portions of the second electrodes 12 and 3122 and the separation membranes 13 and 322. Since the first adhesive layers 1410 and 3410 do not remain on the surfaces of the first electrodes 11 and 3112 and the second electrodes 12 and 3122 in the final battery cell, it is possible to prevent a decrease in cell performance due to the first adhesive layers 1410 and 3410.

[0127] Furthermore, in the basic units 10' and 30' of the present embodiment, the second adhesive layers 1420 and 3420 are located between the first electrode tabs 11t and 3112t and the separation membranes 13 and 322, and between the second electrode tabs 12t and 3122t. Since the second adhesive layers 1420 and 3420 are not dissolved in the electrolyte in the final battery cell, it is possible to prevent the separation membranes 13 and 322 facing the first electrode tabs 11t and 3112t and the second electrode tabs 12t and 3122t from being folded. Also, the second adhesive layers 1420 and 3420 can prevent the first electrodes 11 and 3112 and the second electrodes 12 and 3122 from detaching from the separation membranes 13 and 322 in the final battery cell.

[0128] Also, the second adhesive layers 1420 and 3420 can be formed in a portion excluding the portions where the separation membranes 13 and 322 are in contact with the first electrodes 11 and 3112 and / or the second electrodes 12 and 3122, and are located between a pair of separation membranes 13 and 322 facing each other. That is, the second adhesive layers 1420 and 3420 can be located between a pair of separation membranes 13 and 322 facing each other and not in contact with the first electrodes 11 and 3112 and the second electrodes 12 and 3122.

[0129] As a result, in the basic units 10' and 30' of the present embodiment, the second adhesive layers 1420 and 3420 are formed at positions that avoid the portions where the first electrodes 11 and 3112 and / or the second electrodes 12 and 3122 are in contact with the separator membranes 13 and 322, and the second adhesive layers 1420 and 3420 can prevent the first electrodes 11 and 3112 and / or the second electrodes 12 and 3122 from hindering the lithium ion movement between the separator membranes 13 and 322. That is, the second adhesive layers 1420 and 3420 do not reduce the cell performance, can prevent the above-described separator membranes 13 and 322 from being folded, and can prevent the first electrodes 11 and 3112 and the second electrodes 12 and 3122 from detaching from the separator membranes 13 and 322.

[0130] FIG. 14 is an exploded perspective view of a basic unit according to still another embodiment of the present invention. FIG. 15 is a perspective view showing an electrode assembly in which the components of FIG. 14 are combined. FIG. 16 is a cross-sectional view taken along the A-A axis of FIG. 15.

[0131] Referring to FIGS. 14 and 15, the electrode assembly according to the present embodiment includes a plurality of basic units. The basic unit 109 according to the present embodiment includes a first bonding portion (P1) formed between the electrodes (the first electrode 119 and the second electrode 159) and the separator membranes 219 and 259 along the direction in which the electrodes (the first electrode 119 and the second electrode 159) and the separator membranes 219 and 259 are laminated, and a second bonding portion (P2) formed between the separator membranes 219 and 259 adjacent to each other along the direction in which the electrodes (the first electrode 119 and the second electrode 159) and the separator membranes 219 and 259 are laminated among the plurality of separator membranes 219 and 259. The second bonding portion (P2) is located outside the first bonding portion (P1) along the direction in which the electrodes (the first electrode 119 and the second electrode 159) and the separator membranes 219 and 259 are laminated.

[0132] More specifically, the separator membranes 219 and 259 include a lower separator membrane 219 and an upper separator membrane 259, the electrodes 119 and 159 include a first electrode 119 and a second electrode 159, and the lower separator membrane 219, the first electrode 119, the upper separator membrane 259, and the second electrode 159 can be laminated in this order.

[0133] Here, the first electrode 119 can include a first electrode tab 116 protruding from one direction, and the second electrode 159 can include a second electrode tab 155 protruding from one direction. As an example, as shown in FIGS. 14 and 15, it can be laminated so that the upper separation film 259 is positioned between the first electrode 119 and the second electrode 159, and the first electrode tab 116 of the first electrode 119 and the second electrode tab 155 of the second electrode 159 can be laminated so as to be positioned in opposite directions to each other. However, it is not limited thereto, and a structure laminated so that the first electrode tab 116 and the second electrode tab 155 are positioned in the same direction can also be included in this embodiment. The outside of the aforementioned first adhesive portion (P1) can be positioned in a direction intersecting the direction in which the electrode tabs (the first electrode tab 116 and the second electrode tab 155) protrude.

[0134] Here, the first electrode 119 and the second electrode 159 can each include a current collector electrode and an active material layer positioned on the current collector electrode. Here, the active material layer can be composed of an electrode composition containing an electrode active material. More specifically, the first electrode 119 and the second electrode 159 may be a positive electrode or a negative electrode. Here, the positive electrode can include a positive electrode current collector and an active material layer containing a positive electrode active material, and the negative electrode can include a negative electrode current collector and an active material layer containing a negative electrode active material. As an example, the first electrode 119 can be a negative electrode, and the second electrode 159 can be a positive electrode. However, it is not limited thereto, and the opposite case can also be similarly included in this embodiment.

[0135] The separation films 219 and 259 can separate the first electrode 119 and the second electrode 159 and provide a movement path for lithium ions. Further, the separation films 219 and 259 include a lower separation film 219 and an upper separation film 259, and different or the same material separation films can be applied to the lower separation film 219 and the upper separation film 259.

[0136] As an example, the separation membranes 219 and 259 can be used without special restrictions as long as they are those commonly used as separators in lithium secondary batteries. However, as described above, they can be CCS (Ceramic Coated Separator) as the separation membranes.

[0137] Referring to FIGS. 14 and 16, the first adhesive portion (P1) can be located at least at one of between the first electrode 119 and the lower separation membrane 219, between the first electrode 119 and the upper separation membrane 259, and between the second electrode 159 and the upper separation membrane 259.

[0138] Thereby, the first adhesive portion (P1) can fix the first electrode 119 and the second electrode 159 to the lower separation membrane 219 and / or the upper separation membrane 259, respectively. That is, the first adhesive portion (P1) can prevent the movement between the electrodes (the first electrode 119, the second electrode 159) and the separation membranes 219, 259, and can prevent the deformation and breakage of the electrodes (the first electrode 119, the second electrode 159) and the separation membranes 219, 259.

[0139] Also, the second adhesive portion (P2) can be located between the upper separation membrane 259 and the lower separation membrane 219. More specifically, the second adhesive portion (P2) can be located between the end of the lower separation membrane 219 and the end of the first electrode 119. Also, the second adhesive portion (P2) can be located between the end of the upper separation membrane 259 and the end of the first electrode 119. That is, the second adhesive portion (P2) is located on the surface where the first electrode 119 does not contact with the separation membranes 219, 259, and the second adhesive portion (P2) can be located along the periphery of the first electrode 119. Here, the second adhesive portion (P2) can also be selectively located with respect to the portion where the electrode tabs (the first electrode tab 116, the second electrode tab 155) protruding from the electrodes (the first electrode 119, the second electrode 159) are located.

[0140] As a result, the first electrode 119 is positioned between the upper separation membrane 259 and the lower separation membrane 219, and the upper separation membrane 259 and the lower separation membrane 219 can be fixed to each other by the second adhesive portion (P2), and the movement of the first electrode 119 between the upper separation membrane 259 and the lower separation membrane 219 can be prevented. That is, the second adhesive portion (P2) can fix the upper separation membrane 259 and the lower separation membrane 219 to each other along the peripheral edge of the first electrode 119, and can limit the space in which the first electrode 119 can move, thereby preventing deformation and breakage of the first electrode 119.

[0141] According to this embodiment, the first adhesive 319 that forms the first adhesive portion (P1) and the second adhesive 359 that forms the second adhesive portion (P2) may be of different types from each other. Specifically, the first adhesive may have a property of being dissolved in the electrolytic solution, and the second adhesive may have a property of not being dissolved in the electrolytic solution.

[0142] The content related to the adhesives 14 and 34 described with reference to FIGS. 4, 5, 10, 11, 12, and 13 can all be applied to the first adhesive that forms the first adhesive portion (P1) according to this embodiment. Also, the description regarding the separation membrane described above can also be applied to this embodiment.

[0143] Also, the first adhesive portion (P1) and the second adhesive portion (P2) can be formed in a pattern including a plurality of dots as shown in FIGS. 14 and 16. More specifically, the plurality of dots can be spaced apart from each other. Here, the intervals between the plurality of dots can be adjusted to be the same or different as needed.

[0144] The second adhesive portion can be formed by partially applying an adhesive along the entire length direction of the electrode assembly. The entire length direction may be the same as the direction in which the electrode tabs (the first electrode tab 116 and the second electrode tab 155) protrude.

[0145] Accordingly, the first adhesive part (P1) and the second adhesive part (P2) can be formed in the above-described pattern. After placing an electrode assembly including the basic unit 109 in a case to form a battery cell (secondary battery), when an electrolytic solution is injected into the case, the electrode assembly may be rapidly impregnated.

[0146] More specifically, there is an advantage that a plurality of dots are separated from each other at the first adhesive part (P1) and the second adhesive part (P2), and the electrolytic solution can flow between the plurality of dots. That is, according to the present embodiment, the manufacturing time of the battery cell can be relatively shortened and the yield can also be improved. However, the adhesive pattern formed on the second adhesive part (P2) is not limited to the dot pattern, and as shown in FIG. 21, it can also be formed in a spiral pattern. In addition, the content regarding the adhesive layers 145 and 145' described with reference to FIGS. 17 and 18 to be described later can all be applied to the second adhesive for forming the second adhesive part (P2) according to the present embodiment.

[0147] Hereinafter, an electrode assembly according to another embodiment of the present invention will be described.

[0148] FIGS. 17 and 18 are drawings showing an electrode assembly according to another embodiment of the present invention.

[0149] Referring to FIGS. 17 and 18, the electrode assembly 105 of the present embodiment can include electrodes 115, 125 and a separator 135 as power generation elements capable of charge and discharge. The electrodes 115, 125 included in the electrode assembly 105 can include a positive electrode 115 and a negative electrode 125. By interposing the separator 135 between each electrode (positive electrode 115, negative electrode 125), the electrode assembly 105 can have a structure in which the positive electrode 115 / separator 135 / negative electrode 125 are alternately laminated. Here, the positions of the positive electrode 115 and the negative electrode 125 shown in FIGS. 4 and 5 are shown for convenience, and their positions can be mutually changed.

[0150] In addition, the electrode assembly 105 of this embodiment may include adhesive layers 145 and 145' formed on the side surfaces. The electrode assembly 105 may include adhesive layers 145 and 145' formed on the side surfaces of a cell laminate in which electrodes 115, 125 and the separator 135 are alternately laminated. Here, the cell laminate means the laminate of the electrodes 115, 125 and the separator 135 in the electrode assembly 105 of this embodiment, and may not include the adhesive layers 145 and 145'. Also, here, the side surface of the cell laminate may refer to the surface where the ends of a number of the electrodes 115, 125 and / or the separator 135 are exposed in the cell laminate in which the electrodes 115, 125 and the separator 135 are alternately laminated. The size of the separator 135 during the manufacture of the electrode assembly 105 can be provided larger than the sizes of the electrodes 115, 125, and the ends of the separator 135 can protrude beyond the ends of the electrodes 115, 125. Also, as will be described later, when the electrode assembly 105 is formed through zigzag lamination, the bent portion of the separator 135 can protrude beyond the ends of the electrodes 115, 125. Here, the protruding end of the separator 135 or the bent portion of the separator 135 can be referred to as an "extension portion 138".

[0151] The adhesive layers 145 and 145' can be formed by applying an adhesive. The adhesive can include components that are not easily dissolved in the electrolytic solution. Examples of the adhesive used for the adhesive layers 145 and 145' can include PO, PUR, EVA, and rubber-based adhesives. Also, as other examples, curable adhesives capable of natural curing, moisture curing, UV curing, etc. can be mentioned.

[0152] The adhesive layers 145 and 145' may fix the form of the separator 135 by contacting the extension portion 138 of the separator 135 that does not contact the electrodes 115, 125. The separator 135 and other separators 135 adjacent thereto can be fixed to each other by the adhesive layers 145 and 145'.

[0153] The adhesive layers 145, 145' can be in contact with the separation membrane 135. At this time, the adhesive layer 145 can be formed between the separation membranes 135 as shown in FIG. 17 so that its position corresponds to the extension 138 of the separation membrane 135, and the adhesive layer 145' can also be formed to cover up to the outside of the extension 138 of the separation membrane 135 as shown in FIG. 18.

[0154] In some cases, it is preferable that the adhesive layers 145, 145' do not contact the positive electrode 115. This may be because the adhesive layers 145, 145' may prevent the flow of ions moving from the positive electrode 115 to the negative electrode 125. Also, although it is preferable that the adhesive layers 145, 145' do not contact the negative electrode 125, since the negative electrode 125 is not a direct charging region, the influence may be less than when the positive electrode 115 contacts the adhesive layers 145, 145'.

[0155] The adhesive layers 145, 145' can be formed on all sides of the electrode assembly 105, but in some cases, it may be preferable to form them only on some sides. This is because when the adhesive layers 145, 145' are formed on all sides of the electrode assembly 105, gas release from the electrode assembly 105 may be blocked by the adhesive layer 145 during the electrolyte impregnation or activation process of the electrodes 115, 125.

[0156] The adhesive layers 145, 145' may be formed to entirely cover one side of the electrode assembly 105, or may be formed to cover 70 - 80% of the side. Here, the side of the electrode assembly 105 can have a "height" formed through lamination and a "width" corresponding to the length of the long side or short side in the electrode assembly 105. At this time, the adhesive layers 145, 145' can be formed to cover 70 - 80% of the width of the side of the electrode assembly 105. By not entirely covering the sides of the electrode assembly 105 with the adhesive layers 145, 145', it is possible to prevent the gas release from the electrode assembly 105 from being blocked by the adhesive layers 145, 145' during the electrolyte impregnation or activation process of the electrodes 115, 125.

[0157] The adhesive layers 145 and 145' can be formed on the side surface of the electrode assembly 105 where the long side of the separation membrane 135 is located. The adhesive layers 145 and 145' can be formed on the long side of the separation membrane 135. This is because folding phenomena and the like occur more frequently on the long side, which is relatively longer than the short side of the separation membrane 135. However, such an explanation does not completely exclude the possibility that the adhesive layers 145 and 145' may be formed on the short side of the separation membrane 135.

[0158] FIG. 19 is a photograph of the side surface of the electrode assembly. FIG. 20 is a drawing illustrating a test regarding the rigidity of the electrode assembly.

[0159] Referring to FIGS. 19 and 20, the phenomenon of the ends of the separation membrane 135 being folded can be prevented by the adhesive layers 145 and 145', and the rigidity of the electrode assembly 105 can be complemented.

[0160] Specifically, it was confirmed that by forming the adhesive layers 145 and 145' on the side surface of the electrode assembly 105, the folding phenomenon that appeared in the A region of FIG. 2 described above was improved. Also, in the same test as that performed in FIG. 3, in FIG. 20, since the phenomenon of a part of the electrode assembly 105 sagging did not occur, it was confirmed that the minimum rigidity required for the electrode assembly 105 was ensured by the adhesive layers 145 and 145'. By thus complementing the rigidity of the electrode assembly 105, excessive deformation of the electrode assembly 105 when an external force is applied can be prevented.

[0161] FIG. 21 is a drawing showing an example of an apparatus for applying an adhesive to the electrode assembly and the applied adhesive. FIG. 22 is a drawing showing another example of an apparatus for applying an adhesive to the electrode assembly and the applied adhesive.

[0162] Referring to FIG. 21, the adhesive layers 145, 145' of this embodiment can be formed in a pattern manner. Here, the pattern manner can mean that the adhesive 15 applied to the target position is applied so as to have a predetermined pattern.

[0163] The pattern-type adhesive applicator 205 can include a housing 215 and a nozzle 225. The adhesive 15 can be supplied from the outside of the adhesive applicator 205 and accommodated in the housing 215, and the adhesive 15 that has passed through the nozzle 225 can be ejected in the shape of a line. Specifically, the adhesive coming out of the nozzle 225 can be connected by thin lines and applied in a wobble pattern. The applied adhesive 15 can have a specific pattern by the movement of the nozzle 225. As an example, it is shown that below FIG. 21, the adhesive 15 is applied in a spiral shape and has a pattern shape in which a number of circles overlap. Such a pattern shape can also be referred to as a pig tail shape or a swirl pattern.

[0164] Referring to FIG. 22, the adhesive layers 145, 145' of this embodiment can be formed in a surface coating manner. Here, the surface coating manner can mean that the adhesive 15' is densely applied so that the adhesive 15' is applied to the target position without gaps.

[0165] The surface coating-type adhesive applicator 305 can apply the adhesive 15' so as to cover the entire target portion, as shown in the photograph below FIG. 22. The surface coating-type adhesive applicator 305 can apply the adhesive through spraying, slotting or other methods. As an example, the surface coating-type adhesive applicator 305 can include an air pipe 345 that injects compressed air when the adhesive 15' is ejected through a housing 315, a nozzle 325, a pipe 335 through which the adhesive 15' is supplied inside the housing 315, and the nozzle 325 connected to the pipe 335.

[0166] On the one hand, since the adhesive coating device 305 of the surface coating method in FIG. 22 uses compressed air or the like, there is a risk of a scattering phenomenon in which the adhesive 15' scatters when the adhesive 15' is ejected. Further, when attempting to increase the thickness of the adhesive layers 145, 145', there is a drawback in that the uniformity of the adhesive layers 145, 145' deteriorates.

[0167] On the other hand, since the adhesive coating device 205 in FIG. 21 discharges the adhesive 15 in a linear shape, the phenomenon of adhesive scattering due to air or the like can be minimized, and contamination of the device can be suppressed to a minimum. Further, the adhesive coating device 205 in FIG. 21 can relatively freely adjust the density and thickness of the adhesive layers 145, 145' by adjusting the interval between the lines. The adhesive coating device 205 in FIG. 21 can apply the adhesive 15 more uniformly than the adhesive coating device 305 in FIG. 22 even when attempting to increase the thickness of the adhesive layers 145, 145' by applying the adhesive 15 in a certain pattern.

[0168] The adhesive coating device 205 in FIG. 21 can minimize the thickness of the adhesive layers 145, 145' compared to the adhesive coating device 305 in FIG. 22. Specifically, the thickness of the adhesive layers 145, 145' formed through the adhesive coating device 205 in FIG. 21 is about 100 μm or more, but the thickness of the adhesive layers 145, 145' formed through the adhesive coating device 305 in FIG. 22 can be about 200 μm or more. This may be because, as described above, the adhesive coating device 205 in FIG. 21 applies the adhesive 15 in a linear shape.

[0169] The thicknesses of the adhesive layers 145 and 145' formed on the electrode assembly 105 can be set variously according to the design. For example, the thicknesses of the adhesive layers 145 and 145' can be designed to be equal to or less than the size of the separation space between the electrode assembly 105 inside the battery cell and the battery case. As a specific example, when the electrode assembly 105 is built into the battery case without the adhesive layers 145 and 145' being formed, the separation distance between the electrode assembly 105 and the battery case can be around 600 μm. In such a case, the thicknesses of the adhesive layers 145 and 145' formed on the electrode assembly 105 can be 600 μm or less, 500 μm or less, 400 μm or less, 300 μm or less, 200 μm or less. Also, the thicknesses of the adhesive layers 145 and 145' formed on the electrode assembly 105 can be 100 - 600 μm, 100 - 500 μm, 100 - 400 μm, 100 - 300 μm, or 100 - 200 μm. At this time, the adhesive layers 145 and 145' can be formed by repeatedly laminating lines by the adhesive application device 205 of FIG. 21.

[0170] The adhesives (15, 15') provided through the adhesive application device can have a predetermined temperature. This may be because the adhesive application device adjusts the temperature of the adhesives (15, 15') so that the adhesives (15, 15') can be easily applied. The operating temperature of the adhesive application device 205 of FIG. 21 is 110°C, and the temperature of the adhesive 15 discharged from the adhesive application device 205 can be at the 40°C - 50°C level. The operating temperature of the adhesive application device 305 of FIG. 22 is 160°C, and the temperature of the adhesive 15 discharged from the adhesive application device 205 can be at the 60°C - 70°C level. When the temperature of the adhesive 15 is high, the separation film 135 is likely to shrink. Therefore, in some cases, it may be preferable to use the adhesive application device 205 of FIG. 21 rather than the adhesive application device 305 of FIG. 22 for forming the adhesive layers 145 and 145' of this embodiment.

[0171] FIG. 23 is a photograph comparing the adhesives applied using the devices of FIGS. 21 and 22. FIG. 24 is a magnified photograph of region B in FIG. 23.

[0172] Referring to FIGS. 23 and 24, the coating shape of the adhesive by the devices of FIGS. 21 and 22 can be compared. The shape can be the shape of the adhesive layers 145, 145' applied to the side surfaces of the electrode assembly 105.

[0173] FIG. 23(a) is by a pattern method and may be formed by the adhesive coating device 205 of FIG. 21. In FIG. 23(a), the adhesive 15 discharged in a linear shape forms a pattern by being repeated in a spiral or circular shape. The adhesive layers 145, 145' formed by the pattern method can have a pattern in which at least two lines intersect. The adhesive layers 145, 145' formed by the pattern method can include a number of openings 88. The line width of the adhesive 15 by the pattern method can be 20 to 100 μm, and the interval between the lines can be 100 to 800 μm.

[0174] Referring to FIG. 24, it can be more clearly confirmed that the adhesive layers 145, 145' have a pig's tail pattern. It was confirmed that the first line width (d1) measured from the photograph is 50 μm and the first line interval (w1) is 600 μm.

[0175] On the other hand, FIG. 23(b) is by a surface coating method and may be formed by the adhesive coating device 305 of FIG. 22. FIG. 23(b) has no interval between the adhesives 15' and is applied so as to form a single surface. Different from FIG. 23(a), in FIG. 23(b), a pattern formed by the intersection of at least two lines cannot be seen, and it was confirmed that no openings are formed in the adhesive layers 145, 145'.

[0176] On the other hand, since the adhesive layers 145, 145' of the present embodiment are formed on the side surfaces of the electrode assembly 105, it is possible to prevent the electrolyte absorbed through the side surfaces of the electrode assembly 105 from contacting the electrodes 115, 125. Therefore, the adhesive layers 145, 145' must be formed in a manner that minimizes the reduction in the absorption of the electrolyte.

[0177] Figure 25 is a photograph taken of a test regarding the wettability of an electrode assembly to which the processes of FIGS. 21 and 22 are applied. Specifically, FIG. 25 shows an electrode assembly 105 having adhesive layers 145, 145' formed through the processes of FIGS. 21 and 22 after being impregnated with an electrolytic solution and then disassembled. Through the photograph, portions where the electrolytic solution was not absorbed by electrodes 115, 125 can be confirmed as non-wetting regions 25, and based on this, it can be confirmed whether the wettability of electrodes 115, 125 with respect to the electrolytic solution is reduced by adhesive layers 145, 145'. Here, the smaller the non-wetting region 25, the more sufficient the contact between electrodes 115, 125 and the electrolytic solution is meant to be.

[0178] Referring to FIG. 25, it can be confirmed that the electrode in FIG. 25(a) to which the pattern method of FIG. 21 is applied has a smaller non-wetting region 25 formed than the electrode in FIG. 25(b) to which the surface coating method of FIG. 22 is applied. That is, the adhesive layers 145, 145' formed by FIG. 21 can prevent the absorption of the electrolytic solution less than the adhesive layers 145, 145' formed by FIG. 22.

[0179] Since the pattern coating method of FIG. 21 has a pattern in which a large number of lines intersect, it can be formed to include a large number of openings in adhesive layers 145, 145' of FIGS. 17 and 18. When electrode assembly 105 is impregnated with the electrolytic solution, the electrolytic solution may be absorbed into electrode assembly 105 through the openings. Therefore, the adhesive layers 145, 145' by the pattern coating method can minimize the reduction in the penetration of the electrolytic solution compared to the adhesive layers 145, 145' by the surface coating method.

[0180] If the electrolyte is not properly absorbed by the electrodes 115 and 125, the output characteristics of the electrode assembly 105 may deteriorate. Therefore, even when the adhesive layers 145 and 145' are formed by the surface coating method of FIG. 22, the absorption rate of the electrolyte can also be increased by partially forming the adhesive layers 145 and 145' on the side surfaces of the electrode assembly 105. However, when the adhesive layers 145 and 145' are partially formed in this way, as shown in FIG. 3, the rigidity of the electrode assembly 105 may decrease, so the coating positions and coating levels of the adhesive layers 145 and 145' must be designed more strictly.

[0181] Hereinafter, an electrode assembly according to another embodiment of the present invention will be described. Prior to the description, it is clarified that the electrode assembly of this embodiment is the same as the content of the above-described electrode assembly except that the shape of the cell laminate is different. Therefore, even without separate mention, the electrode assembly according to this embodiment can be described as including all the contents related to the electrode assemblies of FIGS. 17 to 25 described above.

[0182] FIGS. 26 and 27 are drawings showing an electrode assembly according to another embodiment of the present invention.

[0183] Referring to FIGS. 26 and 27, the electrode assembly 105 of this embodiment can include a cell laminate in which the positive electrode 115 / separator 135 / negative electrode 125 are alternately laminated and finishing separators 132 and 134 that wrap the side surfaces of the cell laminate. Here, the separator 135 has a zigzag shape formed by bending a rectangular separator sheet, and the separator 135 bent in a zigzag can be interposed between the positive electrode 115 and the negative electrode 125. After the zigzag lamination is completed, the separator 135 can wrap the side surface of the cell laminate at least once through the finishing separators 132 and 134, thereby finishing the side surface of the cell laminate. At this time, the positions of the positive electrode 115 and the negative electrode 125 shown in FIGS. 26 and 27 are shown for convenience, and their positions can be mutually changed.

[0184] An adhesive layer 145, 145' can be formed on the side surface of the cell laminate. The adhesive layers 145, 145' are in contact with the extension 138 of the separator 135 and can fix the form of the separator 135 by connecting the extension 138. The adhesive layers 145, 145' can fix the overall form of the separator 135 by connecting the bent portions of the separator 135, that is, the bent parts of the separator 135. By the adhesive layers 145, 145', the overall shape of the cell laminate including the separator 135 is fixed, and a minimum rigidity can be ensured.

[0185] As described above, the adhesive layers 145, 145' are formed on all side surfaces of the cell laminate, but can be formed on both side surfaces where the bent separator 135 is located as shown in FIGS. 26 and 27. Also, different from FIGS. 26 and 27, it is also possible to be formed on other side surfaces of the cell laminate. However, in the electrolyte impregnation or activation process of the electrodes 115, 125, since the gas release of the electrode assembly 105 may be hindered by the adhesive layers 145, 145', the positions of the adhesive layers 145, 145' need to be appropriately designed, and it may not be preferable to be formed so as to cover all side surfaces of the cell laminate. Also, the adhesive layers 145, 145' can be formed so as to cover the entire one side surface of the electrode assembly 105, or may be formed so as to cover 70 to 80% of the side surface.

[0186] After the adhesive layers 145, 145' are formed on the cell laminate, finishing separators 132, 134 can be formed outside the adhesive layers 145, 145'. The finishing separators 132, 134 can wrap the side surface of the cell laminate on which the adhesive layers 145, 145' are formed. At this time, the finishing separator 132 can finish after wrapping the side surface of the cell laminate once by wrapping the entire periphery of the cell laminate once as shown in FIG. 26. Also, the finishing separators 132, 134 can also perform a finishing process after wrapping the side surface of the cell laminate two or more times by wrapping the periphery of the cell laminate two or more times as shown in FIG. 27.

[0187] On the other hand, without forming the finishing separation membranes 132 and 134 in the electrode assembly 105, the side surface of the cell laminate can be finished by attaching an adhesive means such as heat fusion or an adhesive tape. In addition to the embodiments as described above, the finishing method can be variously modified and implemented as much as possible.

[0188] Hereinafter, a method for manufacturing an electrode assembly according to an embodiment of the present invention will be described.

[0189] The method (S1000) for manufacturing the electrode assembly of this embodiment can include a step (S1100) of forming a cell laminate in which electrodes 115, 125 and a separation membrane 135 are alternately laminated, a step (S1200) of applying an adhesive 15 to the side surface of the cell laminate, and a step (S1300) of forming adhesive layers 145 and 145' for fixing the separation membrane 135.

[0190] Here, for the step (S1100) of forming the cell laminate, any known method may be used as long as the electrodes and the separation membrane are laminated in the order of the positive electrode 115, the separation membrane 135, the negative electrode 125, the separation membrane 135, or the order of the negative electrode 125, the separation membrane 135, the positive electrode 115, the separation membrane 135. For example, the cell laminate can also be manufactured in a stack type as shown in FIGS. 17 and 18, and can also be manufactured in a zigzag shape as shown in FIGS. 26 and 27.

[0191] Here, for the step (S1200) of applying an adhesive to the side surface of the cell laminate, the adhesive application device 205 in FIG. 21 can also be used, and the adhesive application device 305 in FIG. 22 can be used. When using the adhesive application device 205 in FIG. 21, the step (S1200) can include a step of determining the application pattern of the adhesive 15, and / or a step of pattern-applying the adhesive by moving the nozzle 225 according to the determined pattern. Here, the step of determining the application pattern of the adhesive 15 can also be performed before the step (S1100) of forming the cell laminate.

[0192] Since the adhesive 15 is applied in a viscous state, it may be preferable to fix the form of the adhesive 15 by removing the solvent or moisture in the adhesive. In such a case, the step (S1300) of forming the adhesive layers 145, 145' may include the step of drying the adhesive 15. Also, due to the properties inherent in the adhesive 15, the adhesive 15 may solidify by heat curing or UV curing. In such a case, the step (S1300) of forming the adhesive layers 145, 145' may include the step of curing the adhesive 15.

[0193] On the other hand, in the case of the manufacturing method of the zigzag type electrode assembly 105 shown in FIGS. 26 and 27 of the present embodiment, the above-described manufacturing method may further include a step (S1400) of finishing the side surface of the cell laminate. Through this step, finishing separator films 132, 134 can be formed on the side surface of the cell laminate. The finishing separator films 132, 134 can be subjected to a finishing process after wrapping the side surface of the cell laminate at least once or more. The finishing separator films 132, 134 can wrap the side surface of the cell laminate once as shown in FIG. 26, or can wrap the side surface of the cell laminate two or more times as shown in FIG. 27.

[0194] On the other hand, the electrode assembly 105 of the present embodiment described above can be housed in a cell case together with an electrolytic solution and provided as a secondary battery, that is, a battery cell.

[0195] A battery cell according to an embodiment of the present invention may include an electrode assembly 105 in which a plurality of electrodes and a plurality of separator films are alternately laminated, an electrode lead connected to an electrode tab extending from the plurality of electrodes, and a cell case that seals the electrode assembly with one end of the electrode lead protruding.

[0196] On the other hand, the above-described battery cells can be stacked in one direction to form a battery cell stack, and can be modularized into a battery module to form a battery pack together with a battery management system (BMS) for managing the temperature, voltage, etc. of the battery, and / or a cooling device, etc. The battery pack can be applied to various devices. For example, the devices to which the battery pack is applied can be means of transportation such as electric bicycles, electric vehicles, and hybrid vehicles. However, the above-described devices are not limited to this, and in addition to the above examples, the battery pack according to this embodiment can be used for various devices, which also belongs to the scope of the present invention.

[0197] FIG. 28 is a perspective view showing an initial cell manufacturing stage of a secondary battery manufacturing method according to another embodiment of the present invention. FIG. 29 is a front view showing a formation process of a secondary battery manufacturing method according to another embodiment of the present invention.

[0198] Referring to FIG. 28, the secondary battery manufacturing method according to this embodiment can include an initial cell manufacturing stage after the electrode assembly manufacturing stage.

[0199] The initial cell manufacturing stage can be a stage of manufacturing the initial cell 0 in FIG. 29 by accommodating the above-described electrode assemblies 1, 2, 3, 4 in the pouch case 70, injecting an electrolytic solution into the pouch case 70, and then sealing the edge 71 of the pouch case. The pouch case 70 can include a gas pocket portion 75 extending to one side of a cup portion 74 in which the electrode assemblies 1, 2, 3, 4 are accommodated. After accommodating the electrode assemblies 1, 2, 3, 4 and the electrolytic solution in the cup portion, the edge 71 of the pouch case can be sealed.

[0200] In this case, the sealing can be performed at the edge of the cup portion 74 and the outer corner edge of the gas pocket portion 75. That is, the edge of the region combining the cup portion 74 and the gas pocket portion 75 can be sealed in a way that draws a closed curve, so that the region combining the cup portion 74 and the gas pocket portion 75 can be sealed from the outside. That is, it is isolated from the outside, and after sealing, the cup portion 74 and the gas pocket portion 75 can communicate with each other.

[0201] When the initial cell 0 in FIG. 29 is manufactured in a form sealed from the outside, the stage of post-processing the initial cell 0 to manufacture the final cell can be performed. In the final cell manufacturing stage, the adhesive applied to at least one of the surfaces of the electrode and the separation membranes 13 and 322 in the previous basic unit manufacturing stage can be dissolved. The electrolytic solution contained in the initial cell 0 may be an organic solvent, and the fact that the adhesives 14 and 34 dissolve may mean that the adhesives 14 and 34 dissolve into the electrolytic solution which is an organic solvent.

[0202] This can mean that the adhesives 14 and 34 applied and existing on the surface of the electrode or the separation membranes 13 and 322 have a reduced coating area, or that all of the applied adhesives 14 and 34 disappear.

[0203] Here, in the case of the electrodes 11, 12, and 31, it can be meant that no adhesives 14 and 34 remain on the electrode surface.

[0204] Also, in the case of the separation membranes 13 and 322, since the separation membranes 13 and 322 are generally porous sheets, part of the adhesives 14 and 34 may penetrate into the separation membranes 13 and 322. At this time, in the above-mentioned final cell manufacturing stage, the adhesives 14 and 34 that have penetrated into the separation membranes 13 and 322 may dissolve in the electrolytic solution, and in this process, coating marks of the adhesives 14 and 34 may remain on the separation membranes 13 and 322.

[0205] Here, the coating marks of the adhesives 14 and 34 can mean that although the components of the adhesives 14 and 34 do not remain, a part of the outer surfaces of the separator films 13 and 322 is deformed by the adhesives 14 and 34. However, it is not limited to this. The coating marks of the adhesives 14 and 34 can mean traces that can confirm the presence or absence of the application of the adhesives 14 and 34 in various ways, like traces that can confirm the presence or absence of the application of the adhesives 14 and 34 with the naked eye.

[0206] Thereby, the coating marks of the adhesives 14 and 34 formed on the separator films 13 and 322 can be formed at the same positions as the positions where the adhesives 14 and 34 are applied.

[0207] In particular, the adhesives 14 and 34 for electrode-separator adhesion used in the secondary battery manufacturing method according to this embodiment can be acrylate-based adhesives. By using the acrylate-based adhesives 14 and 34, the adhesives 14 and 34 can dissolve and enter the electrolytic solution.

[0208] In the secondary battery manufacturing method according to this embodiment, the final cell manufacturing stage can include a formation process of activating the initial cell 0 while charging at a high temperature higher than room temperature. The formation process (activation process) is a process of forming an SEI layer (SEI Layer) on the surface of the electrode plate of the electrode assembly through the charging process and making it charged, whereby the secondary battery can be formed so as to be able to supply power.

[0209] In the final cell manufacturing stage, the formation process can be carried out at a temperature of 45 degrees Celsius or higher. And at least a part of the adhesives 14 and 34 can be dissolved in the formation process. And more preferably, in the final cell manufacturing stage, the formation process can be carried out at a temperature between 50 degrees Celsius and 70 degrees Celsius. At 50 degrees Celsius or higher, where the temperature is higher than 45 degrees Celsius, the dissolution of the adhesive 14 can occur better. And at a temperature of 70 degrees Celsius or higher, there may be a performance degradation of the cell product, so it may not be preferable.

[0210] Also, referring to FIG. 29, in the final cell manufacturing stage of the secondary battery manufacturing method according to this embodiment, the formation process can include a jig pressing process of pressing both side surfaces of the initial cell 0 using the jig 500. It can be a method of pressing the left side of the initial cell 0 with the left jig 510 and pressing the right side jig 520 of the initial cell 0 with the right jig 520. When pressing the initial cell 0 with the jig 500, the gas generated inside the electrode assemblies 1, 2, 3, 4 can smoothly move to the gas pocket portion 75 in FIG. 29. The gas that has moved to the gas pocket portion 75 can be smoothly discharged to the outside of the cell in a later degassing process. By performing the jig pressing process in the formation process, the process of dissolving the adhesives 14, 34 in the electrolytic solution can be made easier.

[0211] Here, the jig pressing process can include a process of applying and then releasing the pressure of the jig 500 that presses both side surfaces of the initial cell 0. That is, at least two cycles of the process of applying and then releasing the pressure of the jig 500 on the initial cell 0 can be repeated.

[0212] The process of one cycle of applying and then releasing the pressure of the jig 500 can be a process of directly exerting physical force in a manner of alternately applying positive pressure and negative pressure to the adhesives 14, 34 during dissolution. Therefore, the effect of making the dissolution of the adhesives 14, 34 be carried out even more remarkably can be obtained.

[0213] In this case, for more systematic operation, a control device can be connected to the jig device. Based on this, the positive pressure time and the negative pressure time can be adjusted, and the magnitude of the positive pressure and the magnitude of the negative pressure can also be controlled. Thereby, a more effective adhesive dissolution system can be realized.

[0214] In particular, in the final cell manufacturing stage of the secondary battery manufacturing method according to an embodiment of the present invention, the formation process is performed at a temperature between 55 and 65 degrees Celsius, and at the same time, it can include a jig pressing process of pressing both side surfaces of the initial cell 0 using the jig 500. In this case, all of the adhesives 14 and 34 may be dissolved in the formation process, and there may be no adhesives 14 and 34 remaining on the electrode surface. Also, as described above, there may be traces of the adhesives 14 and 34 remaining on the separator films 13 and 322.

[0215] When the adhesives 14 and 34 remain on the electrode surface, the area where the adhesives 14 and 34 remain becomes an unreacted area where no electrode reaction occurs, and there is a possibility of a decrease in battery performance. However, as in the present invention, when all of the adhesives 14 and 34 are dissolved and disappear from the surfaces of the electrode and / or the separator films 13 and 322, the unreacted area due to the adhesives 14 and 34 disappears, performance degradation is prevented, and excellent battery performance can be achieved.

[0216] On the other hand, the final cell manufacturing stage of the secondary battery manufacturing method according to this embodiment can further include a pre-aging process of storing the initial cell 0 at room temperature before the formation process. The pre-aging process at room temperature can be performed for about 1.5 days. The pre-aging process may be a process that gives time so that the electrolytic solution can be sufficiently impregnated between the electrode and the separator films 13 and 322. Of course, at least a part of the adhesives 14 and 34 can be dissolved even in the pre-aging process.

[0217] When the electrolytic solution according to this embodiment is a gel-type electrolytic solution, the secondary battery manufacturing method according to this embodiment can further include a stage called pre-charging (see FIG. 31) before and after the electrolytic solution impregnation process. As an example, it can be charged up to 1.7V with a current of 0.05C.

[0218] In addition, the final cell manufacturing stage of the secondary battery manufacturing method according to this embodiment may further include a normal temperature aging process of storing the initial cell 0 at normal temperature after the formation process. The normal temperature aging process can be carried out for about one day. Also, the final cell manufacturing stage may further include a high temperature aging process of storing the initial cell 0 at a temperature of 60 to 65 degrees Celsius after the normal temperature aging process and before the degassing process. Here, the order of the normal temperature aging process and the high temperature aging process can also be interchanged.

[0219] In addition, the final cell manufacturing stage of the secondary battery manufacturing method according to this embodiment may include a degassing process after the high temperature aging process. The degassing process may be a process of discharging the internal gas of the initial cell 0 to the outside. The gas discharged in the degassing process may mainly be the internal gas generated in the formation process and stored in the gas pocket portion 75. The degassing process can form a through hole in the gas pocket portion 75 so that the gas is discharged to the outside.

[0220] The final cell manufacturing stage may include a resealing process of resealing the initial cell 0 again so as to be sealed from the outside after the degassing process. Thereby, the final cell manufacturing stage can manufacture the final cell. On the surface of the internal electrode of the final cell manufactured in this way, or the separator 13, 322, the adhesives 14, 34 may be dissolved and may not remain any more. In particular, on the separators 13, 322, as described above, there may be traces of the application of the adhesives 14, 34 remaining.

[0221] On the other hand, the secondary battery manufacturing method according to this embodiment may further include a finishing charge and discharge stage of charging and discharging the final cell after the final cell manufacturing stage. The finishing charge and discharge stage may include a process of measuring the battery capacity of the final cell, and may include a process of finally charging the battery to a set voltage for shipment of the final product.

[0222] When the electrolyte according to this embodiment is a gelrite electrolyte, the method for manufacturing a secondary battery according to this embodiment can further include a step of curing (see Fig. 31) at approximately 60 to 65 degrees Celsius for about 5 hours before the formation step. Through the curing step, the liquid electrolyte can be cured into a gel state. Further, it is preferable to perform jig curing in order to cure the electrolyte uniformly within the electrode. In the jig curing step, the electrolyte can be cured uniformly within the electrode by curing while applying uniform pressure to both sides of the battery cell. This is because when the jig curing step is performed, the electrolyte can be uniformly dispersed within the electrode.

[0223] Hereinafter, the content of the present invention will be described through more specific experimental examples. However, the following experimental examples are for explaining the present invention by way of example, and the scope of the present invention is not limited thereto.

[0224] <Experimental Example - Confirmation of Adhesive Coating Marks> A battery cell was manufactured that houses both an electrode assembly in which a positive electrode, a negative electrode, and a separator are alternately laminated and an electrolyte. Here, an adhesive is applied in a plurality of dot shapes between the positive electrode and the separator and between the negative electrode and the separator. Here, the separator is a CCS (Ceramic Coated Separator), the adhesive contains an acrylate-based adhesive substance, and the electrolyte can be a standard electrolyte in which EC (ethylene carbonate) and EMC (ethyl methyl carbonate) are mixed at a ratio of 3:7.

[0225] Thereafter, the manufactured battery cell was charged, the separator was separated from the charged battery cell, the separated separator was washed and dried with acetone, the electrolyte absorbed by the separated separator was removed, and then the surface of the separator was observed. The results are shown in Fig. 30. Fig. 30(a) is an image confirmed with the naked eye, and Fig. 30(b) is an image taken by magnifying with a microscope.

[0226] <Analysis of Experimental Results - Confirmation of Adhesive Coating Marks> Referring to FIGS. 30(a) and (b), it can be confirmed that in the separator separated from the charged battery cell, the adhesive leaves a trace on the separator. In particular, when magnified and photographed with a microscope as shown in FIG. 30(b), it can be confirmed that the adhesive coating marks left on the separator are more easily observable.

[0227] That is, it can be confirmed that in the battery cell according to this embodiment, in the electrode assembly unit, the adhesive was applied between the positive electrode and the separator and between the negative electrode and the separator through the adhesive coating marks left on the outer surface of the separator.

[0228] As described above, the present invention has been described with reference to limited embodiments and drawings, but the present invention is not limited thereto, and various modifications can be made by those having ordinary knowledge in the technical field to which the present invention pertains within the equivalent scope of the technical idea of the present invention and the claims described below.

Explanation of Reference Numerals

[0229] 0 Initial cell 1, 2, 3, 4 Electrode assembly 70 Pouch case 71 Edge of the pouch case 75 Gas pocket part 10, 30 Basic unit 11, 119, 3112 First electrode 11-1, 311 First electrode reel 12, 3122 Second electrode 12-1, 312 Second electrode reel 13, 322 Separator 14, 15, 34 Adhesive 20, 40 Electrode laminate 50 Fixed tape 60 Electrode lead 110 Lower separator reel 111 Lower separator sheet 120 Upper separator reel 121 Upper separator sheet 130 Four-layer structure laminate 138 extension part 205, 305 adhesive application devices 210, 371 nozzles 211, 371 first nozzles 212, 372 second nozzles 213 third nozzle 221, 331 first cutters 222, 332 second cutters 223 third cutter 230 pressure nip roll 341, 342 first and second transfer devices 500 jig 510 left jig 520 right jig P1, P2 first and second bonding parts

Claims

1. In an electrode assembly in which electrodes and separation membranes are alternately laminated, a first adhesive portion formed between the electrode and the separation membrane, and including a second adhesive portion formed between adjacent separation membranes among the plurality of separation membranes included in the electrode assembly, the second adhesive portion is located outside the first adhesive portion, the first adhesive for forming the first adhesive portion and the second adhesive for forming the second adhesive portion are of different types from each other, the first adhesive has a property of dissolving in an electrolytic solution, an electrode assembly.

2. The electrode assembly according to claim 1, wherein the second adhesive has a property of not dissolving in an electrolytic solution.

3. The electrode assembly according to claim 1, wherein the first adhesive portion includes an adhesive pattern disposed at the same position for each between the electrode and the separation membrane.

4. The electrode assembly according to claim 1, wherein the first adhesive portion includes an adhesive pattern disposed in a form intersecting with each other for each between the electrode and the separation membrane.

5. The electrode assembly according to claim 1, wherein the separation membrane is not coated with a binder on its surface or the content of the binder coated on the surface is 3 wt% or less.

6. Further including an electrode tab protruding from one end of the electrode, The electrode assembly according to claim 1, wherein the outside of the first adhesive portion is located in a direction intersecting with the direction in which the electrode tab protrudes.

7. The electrode assembly according to claim 6, wherein the second adhesive portion is located between the electrode tab and the separation membrane.

8. The electrode assembly according to claim 1, wherein at least one of the first adhesive portion and the second adhesive portion is formed by applying an adhesive in a dot shape.

9. The first bonding portion is formed by applying the adhesive in a dot shape, and the electrode assembly according to claim 8.

10. The second bonding portion is formed of an adhesive layer having a plurality of openings, and the electrode assembly according to claim 8.

11. The adhesive layer forming the second bonding portion is formed by partially applying the adhesive along the entire length direction of the electrode assembly, and the electrode assembly according to claim 10.

12. Further including an electrode tab protruding from one end of the electrode, The entire length direction is the same as the direction in which the electrode tab protrudes, and the electrode assembly according to claim 11.

13. The second bonding portion connects the extension portions of the separation film extending from the periphery corresponding to the long side of the electrode to each other, and the electrode assembly according to claim 1.

14. The separation film has a zigzag shape formed by folding a rectangular separation film sheet, and the electrode assembly according to claim 1.

15. A finishing separation film is located outside the second bonding portion, and the electrode assembly according to claim 14.

16. The separation film has long sides facing each other and short sides facing each other, The adhesive layer forming the second bonding portion is formed along the long side of the separation film, and the electrode assembly according to claim 13.

17. The electrode includes a positive electrode and a negative electrode, The end portion of the positive electrode does not contact the adhesive layer forming the second bonding portion, and the electrode assembly according to claim 16.

18. The electrode assembly according to claim 16, wherein the adhesive layer forming the second adhesive portion has a pattern shape in which at least two lines intersect.

19. An electrode assembly in which electrodes and separator membranes are alternately laminated; and A pouch case containing the electrode assembly and an electrolytic solution, wherein at least one adhesive coating mark remains on the surface of the separator membrane in contact with the electrode, A secondary battery in which an adhesive portion is formed between adjacent separator membranes among a plurality of separator membranes included in the electrode assembly.

20. The secondary battery according to claim 19, wherein the adhesive coating mark is a trace of the adhesive layer formed between the electrode and the separator membrane being dissolved in the electrolytic solution.

21. The adhesive layer is formed by applying an adhesive in a plurality of dot shapes, The secondary battery according to claim 20, wherein the adhesive coating mark is formed in a dot shape at the position where the adhesive layer is formed.

22. The adhesive is an acrylate-based adhesive, The secondary battery according to claim 21, wherein the electrolytic solution is an organic solvent.

23. The electrode includes a first electrode and a second electrode, The separator membrane includes an upper separator membrane and a lower separator membrane, The secondary battery according to claim 19, wherein the electrode assembly has a structure in which the lower separator membrane, the first electrode, the upper separator membrane, and the second electrode are alternately laminated.

24. The electrode includes a first electrode and a second electrode, The electrode assembly is wherein the first electrode is placed on the separator membrane, and one side of the separator membrane is folded to cover the first electrode, The secondary battery according to claim 19, wherein the second electrode is placed on the separation membrane, and the other side of the separation membrane is folded to cover the second electrode.

25. An electrode tab is formed at one end of the electrode, An adhesive layer is formed between the electrode tab and the separation membrane, The secondary battery according to claim 23 or 24, wherein the adhesive layer contains an adhesive component that does not dissolve in the electrolyte.

26. The secondary battery according to claim 25, wherein the adhesive layer is formed by applying the adhesive in a plurality of dot shapes.

27. The secondary battery according to claim 19, wherein the electrolyte is a Gelyte electrolyte.

28. The secondary battery according to claim 27, wherein the electrolyte contains a fluorine-based, poly-carbonate-based, or silicon-based oligomer.

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