Secondary battery manufacturing apparatus and secondary battery manufacturing method

Abstract

A method for manufacturing a secondary battery according to an embodiment of the present invention includes: an electrode assembly manufacturing step of manufacturing an electrode assembly in which electrodes and separators are fixed by an adhesive so that the electrodes and separators are alternately stacked; and a battery cell manufacturing step of manufacturing a battery cell by housing the electrode assembly together with an electrolyte in a pouch case and sealing the pouch case, wherein the electrode assembly manufacturing step includes a step of forming a first adhesive portion between the electrodes and the separator and a second adhesive portion between adjacent separators among a plurality of separators included in the electrode assembly, and the second adhesive portion is formed to be disposed outside the first adhesive portion in a direction perpendicular to a direction in which the electrodes and the separators are stacked.

Description

[Technical Field]

[0001] Cross-citation with related applications (etc.) This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0005741, filed on January 14, 2022, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a secondary battery manufacturing apparatus and a secondary battery manufacturing method, and more particularly to a secondary battery manufacturing apparatus and a secondary battery manufacturing method that prevent a defect rate in the process and a decrease in battery performance. [Background technology]

[0003] Generally, types of secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, lithium-ion polymer batteries, etc. These secondary batteries are used not only in small products such as digital cameras, P-DVDs, MP3 players, mobile phones, PDAs (registered trademark), portable game devices, power tools, and e-bikes, but also in large products that require high output, such as electric vehicles and hybrid vehicles, as well as in power storage devices and backup power storage devices that store surplus generated power and renewable energy.

[0004] To manufacture such a secondary battery, first, an electrode active material slurry is applied to a positive electrode current collector and a negative electrode current collector to form a positive electrode and a negative electrode, which are then stacked on both sides of a separator to form an electrode assembly of a predetermined shape, and then the electrode assembly is placed in a battery case, an electrolyte is injected, and the battery case is sealed.

[0005] Electrode assemblies are classified into various types, such as the simple stack type, in which positive electrodes, separators, and negative electrodes are simply stacked in a cross pattern without fabricating unit cells; the lamination and stack (L&S) type, in which unit cells are first fabricated using positive electrodes, separators, and negative electrodes and then stacked; the stack and folding (S&F) type, in which multiple electrodes or unit cells are attached at a distance to one side of a long separator sheet and the separator sheet is repeatedly folded from one end in the same direction; and the Z-folding type, in which multiple electrodes or unit cells are alternately attached to one side and the other side of a long separator sheet and the separator sheet is repeatedly folded from one end in a specific direction and then in the opposite direction.

[0006] Among these, to manufacture a lamination-and-stack type, stack-and-fold type, or Z-fold type electrode assembly, a unit cell may be first manufactured. Generally, to manufacture a unit cell, a separator may be laminated on each of the top and bottom surfaces of a central electrode, and then a top electrode may be laminated on top of the central electrode. A lamination process may then be performed in which heat and pressure are applied to the laminated structure of the electrodes and separator. By performing this lamination process, the electrodes and separator are bonded to each other, thereby forming a solid unit cell.

[0007] However, in the past, before a lamination process was performed on a laminate in which electrodes and separators were stacked, the electrodes and separators were simply in contact with each other without being bonded to each other. Therefore, there was a problem that the electrodes would come off the correct position during the process of transporting the laminate to perform the lamination process. Furthermore, the lamination process required the application of high heat and pressure to the laminate, which could result in damage to the electrodes. Furthermore, while separators that can be bonded to electrodes with low heat and pressure have recently been developed, they have had problems such as excessively high manufacturing costs, making them uneconomical, and reducing process efficiency.

[0008] On the other hand, one possible solution to this problem is to fabricate unit cells using adhesives. However, in this case, the adhesive is present on the surface of the electrodes, preventing the electrodes from performing their intended functions in those areas, resulting in a decrease in battery performance. Summary of the Invention [Problem to be solved by the invention]

[0009] An object of the present invention is to provide an apparatus and method for manufacturing a secondary battery that prevents an electrode or a separator from being separated from a proper position when a unit cell is manufactured by stacking electrodes and a separator.

[0010] In addition, the present invention provides a secondary battery manufacturing apparatus and method that can reduce production costs compared to conventional methods for manufacturing basic unit cells using lamination, reduce the rate of defects in the process caused by high heat and pressure, and prevent deterioration of battery performance.

[0011] However, the problems to be solved by the embodiments of the present invention are not limited to the above problems, and can be variously expanded within the scope of the technical ideas included in the present invention. [Means for solving the problem]

[0012] A method for manufacturing a secondary battery according to one embodiment of the present invention includes: an electrode assembly manufacturing step of manufacturing an electrode assembly in which electrodes and separators are fixed with an adhesive so that the electrodes and separators are alternately stacked; and a battery cell manufacturing step of manufacturing a battery cell by placing the electrode assembly together with an electrolyte in a pouch case and sealing the pouch case. The electrode assembly manufacturing step includes a step of forming a first adhesive portion between the electrodes and the separator and a second adhesive portion between adjacent separators among a plurality of separators included in the electrode assembly, and the second adhesive portion is formed to be disposed outside the first adhesive portion in a direction perpendicular to a direction in which the electrodes and the separators are stacked.

[0013] The first adhesive forming the first adhesive portion and the second adhesive forming the second adhesive portion may be different in type from each other.

[0014] At least a portion of the first adhesive may dissolve in the electrolyte solution, leaving a trace of the adhesive on the separator.

[0015] The second adhesive may be insoluble in the electrolyte solution.

[0016] The first adhesive portion may be formed to include adhesive patterns disposed at the same positions between the electrodes and the separators.

[0017] The first adhesive portion may be formed to include adhesive patterns disposed in a crossing shape between the electrode and the separator.

[0018] At least one of the first adhesive portion and the second adhesive portion may be formed by applying adhesive in a dot pattern.

[0019] The first adhesive portion may be formed by applying adhesive in a dot pattern.

[0020] The second adhesive portion may be formed of an adhesive layer having a plurality of openings.

[0021] The separator may be formed in a zigzag shape by folding a rectangular separator sheet.

[0022] The separation membrane may have opposing long sides and opposing short sides, and the adhesive layer forming the second adhesive portion may be formed along the long sides of the separation membrane.

[0023] The adhesive layer forming the second adhesive portion may be formed by applying an adhesive in a wobble pattern, and the wobble pattern may have a pattern shape in which two lines intersect.

[0024] In the secondary battery manufacturing method, the battery cell manufacturing step may further include a formation process of activating the battery cell by charging it at a temperature higher than room temperature, and at least a portion of the adhesive may be dissolved in the electrolyte solution in the formation process.

[0025] The formation step may be carried out at a temperature of 50 degrees Celsius or more and 70 degrees Celsius or less.

[0026] The formation step may include a jig pressing step of pressing both side surfaces of the initial cell using a jig.

[0027] The formation process may be performed at a temperature of 55°C to 65°C, and the adhesive may be completely dissolved in the electrolyte during the formation process, thereby removing the adhesive located on the surface of the electrode.

[0028] The manufacturing step of the battery cell may further include a pre-charging step.

[0029] The battery cell manufacturing step may further include a curing step before the formation step.

[0030] The adhesive may be an acrylate adhesive, and the electrolyte may be an organic solvent.

[0031] The method for manufacturing a secondary battery may further include manufacturing a radical unit, which is a laminated unit of the electrode and the separator, and the electrode assembly may be manufactured by attaching a fixing tape around an electrode laminate formed by stacking a plurality of the radical units.

[0032] The step of manufacturing the basic unit may include the steps of unwinding a lower separation membrane from a lower separation membrane reel, applying adhesive to at least a portion of an upward surface of the unwound lower separation membrane using a first nozzle, and placing a first electrode on the adhesive-coated surface of the lower separation membrane, unwinding an upper separation membrane from an upper separation membrane reel, applying adhesive to at least a portion of an upward surface of the unwound upper separation membrane using a second nozzle, and applying adhesive to at least a portion of an upward surface of the upper separation membrane using a third nozzle, and placing a second electrode on the adhesive-coated surface of the upper separation membrane after the third nozzle has applied the adhesive.

[0033] The first nozzle, the second nozzle, and the third nozzle may apply the adhesive in the form of a plurality of dots.

[0034] The method for manufacturing a secondary battery may further include a step of manufacturing a radical unit in which the separator is folded to cover the electrode and the electrode and the separator are stacked, and the electrode assembly may be manufactured by repeatedly forming the radical unit.

[0035] The basic unit manufacturing step includes a step of unwinding an electrode sheet from an electrode reel and forming a plurality of electrodes from the electrode sheet, a step of unwinding a separation membrane to be laminated with the electrodes from a separation membrane reel, a step of placing the separation membrane on an upper surface of a table, and a step of applying adhesive to at least a portion of the separation membrane and the electrodes placed on the table using a nozzle, and the electrodes may include a first electrode and a second electrode.

[0036] The method for manufacturing a secondary battery may further include a folding step after the adhesive applying step, wherein in the folding step, when the first electrode is placed on the separator, one side of the separator may be folded to cover the first electrode, and when the second electrode is placed on the separator, the other side of the separator may be folded to cover the second electrode.

[0037] The nozzle may apply the adhesive in the form of a plurality of dots.

[0038] The electrolyte may be a Gelyte electrolyte.

[0039] The electrolyte may include a fluorine-based, polycarbonate-based, or silicon-based oligomer.

[0040] According to another embodiment of the present invention, a secondary battery manufacturing apparatus is an apparatus for manufacturing a secondary battery including an electrode assembly formed by alternately stacking electrodes and separators, and includes an electrode reel from which an electrode sheet on which a plurality of electrodes are formed is unwound, a separator reel from which a separator sheet to be stacked together with the electrodes is unwound, and a nozzle for applying adhesive to at least one of the electrode sheet, the electrode, the separator sheet, and the separator, and by changing the type of adhesive injected through the nozzle, a first adhesive portion may be formed between the electrode and the separator, and a second adhesive portion may be formed between adjacent separators among the plurality of separators included in the electrode assembly.

[0041] The nozzle may include a plurality of nozzles, and adhesives for forming the first adhesive portion and the second adhesive portion may be applied through different nozzles.

[0042] The separation membrane reel may include a lower separation membrane reel that unwinds a lower separation membrane sheet and an upper separation membrane reel that unwinds an upper separation membrane sheet.

[0043] The apparatus may include a first nozzle that applies adhesive to at least a portion of one upward-facing surface of the lower separation membrane sheet unwound from the lower separation membrane reel, a second nozzle that applies adhesive to at least a portion of the upper separation membrane sheet that abuts against an electrode fixed to the one surface of the lower separation membrane sheet to which the adhesive has been applied, and a third nozzle that applies adhesive to at least a portion of the other upward-facing surface of the upper separation membrane sheet.

[0044] The first nozzle, the second nozzle, and the third nozzle may apply the adhesive in the form of a plurality of dots.

[0045] The secondary battery manufacturing apparatus may further include pressure nip rolls disposed on both upper and lower surfaces of a stack including the lower separator sheet, an electrode fixed to one surface of the lower separator sheet, the upper separator sheet, and an electrode fixed to the other surface of the upper separator sheet, and configured to apply pressure to the stack.

[0046] The secondary battery manufacturing apparatus may further include a cutter that cuts the stack at predetermined intervals.

[0047] The secondary battery manufacturing apparatus may further include a cutter for cutting the electrode sheet into a predetermined size and placing the cut sheet on one side of the lower separator sheet.

[0048] The secondary battery manufacturing apparatus may further include a table on which the separator is fixed, and the adhesive may be applied to the separator in a state where the separator is fixed on the table.

[0049] The secondary battery manufacturing apparatus may further include a header that adsorbs the electrode, and a transfer device that transfers the electrode so that the header adsorbs the electrode.

[0050] The nozzle for forming the second adhesive portion may apply adhesive in a wobble pattern. [Effects of the Invention]

[0051] According to the embodiment, when electrodes and separators are alternately stacked to manufacture an electrode assembly, the adhesive can prevent the electrodes or separators from being separated from their proper positions.

[0052] Furthermore, at least a portion of the adhesive dissolves in the electrolyte solution, forming adhesive traces on the separator, and the adhesive traces do not contain any adhesive components, thereby preventing the adhesive from degrading the battery's performance.

[0053] In addition, compared to the conventional method of manufacturing basic unit cells by lamination, the production cost can be reduced and the defect rate during the process caused by high heat and pressure can be reduced. [Brief explanation of the drawings]

[0054] [Figure 1] FIG. 1 is a flowchart showing a method for manufacturing a secondary battery according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view illustrating a step of manufacturing a basic unit in a method of manufacturing a secondary battery according to an embodiment of the present invention. [Figure 3] FIG. 3 is a front view illustrating a step of manufacturing a basic unit in a method of manufacturing a secondary battery in accordance with an embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional view showing an electrode assembly formed by stacking radical units manufactured in the radical unit manufacturing step of a secondary battery manufacturing method in accordance with an embodiment of the present invention. [Figure 5]FIG. 5 is a cross-sectional view showing an electrode assembly formed by stacking radical units manufactured in a radical unit manufacturing step of a secondary battery manufacturing method in accordance with another embodiment of the present invention. [Figure 6] FIG. 6 is a schematic view showing a step of manufacturing a basic unit in a method of manufacturing a secondary battery according to another embodiment of the present invention. [Figure 7] FIG. 7 is a schematic view showing a step of manufacturing a basic unit in a method of manufacturing a secondary battery according to another embodiment of the present invention. [Figure 8] FIG. 8 is a schematic view showing a step of manufacturing a basic unit in a method of manufacturing a secondary battery according to another embodiment of the present invention. [Figure 9] FIG. 9 is a schematic view showing a step of manufacturing a basic unit in a method of manufacturing a secondary battery according to another embodiment of the present invention. [Figure 10] FIG. 10 is a cross-sectional view illustrating an electrode assembly manufactured by repeatedly forming the radical units manufactured by the radical unit manufacturing step of the method for manufacturing a secondary battery in accordance with another embodiment of the present invention. [Figure 11] FIG. 11 is a cross-sectional view illustrating an electrode assembly manufactured by repeatedly forming radical units manufactured by the radical unit manufacturing step of a method for manufacturing a secondary battery in accordance with another embodiment of the present invention. [Figure 12] FIG. 12 is an exploded perspective view of a radical unit manufactured in a radical unit manufacturing step of a method for manufacturing a secondary battery in accordance with another embodiment of the present invention. [Figure 13] FIG. 13 is an exploded perspective view of a radical unit manufactured in a radical unit manufacturing step of a method for manufacturing a secondary battery in accordance with another embodiment of the present invention. [Figure 14] FIG. 14 is an exploded perspective view of a radical unit according to still another embodiment of the present invention. [Figure 15] FIG. 15 is a perspective view showing an electrode assembly in which the components of FIG. 14 are combined. [Figure 16] FIG. 16 is a cross-sectional view taken along the AA axis in FIG. [Figure 17] FIG. 17 is a view showing an electrode assembly according to another embodiment of the present invention. [Figure 18] FIG. 18 is a view showing an electrode assembly according to another embodiment of the present invention. [Figure 19] FIG. 19 is a photograph of the side of the electrode assembly. [Figure 20] FIG. 20 shows a test on the stiffness of the electrode assembly. [Figure 21] FIG. 21 is a diagram showing an example of an apparatus for applying adhesive to an electrode assembly and the applied adhesive. [Figure 22] FIG. 22 is a diagram showing another example of an apparatus for applying adhesive to an electrode assembly and the applied adhesive. [Figure 23] FIG. 23 is a photograph comparing adhesives applied using the apparatus of FIGS. 21 and 22. [Figure 24] FIG. 24 is an enlarged photograph of region B in FIG. [Figure 25] FIG. 25 is a photograph showing a wettability test of an electrode assembly to which the steps of FIGS. 21 and 22 are applied. [Figure 26] FIG. 26 is a view showing an electrode assembly according to another embodiment of the present invention. [Figure 27] FIG. 27 is a view showing an electrode assembly according to another embodiment of the present invention. [Figure 28] FIG. 28 is a perspective view showing an initial cell manufacturing step of a method for manufacturing a secondary battery in accordance with another embodiment of the present invention. [Figure 29] FIG. 29 is a front view showing a formation step of a method for manufacturing a secondary battery according to another embodiment of the present invention. [Figure 30] FIG. 30 shows traces of adhesive remaining on the surface of the separation membrane. [Figure 31] FIG. 31 is a flowchart showing a method for manufacturing a secondary battery according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0055] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily understand the preferred embodiments of the present invention. However, the present invention may be embodied in various different forms and should not be construed as being limited to or by the following examples.

[0056] In order to clearly explain the present invention, detailed descriptions of parts that are not relevant to the explanation or related known technologies that unnecessarily obscure the gist of the present invention are omitted, and when adding reference symbols to components in each drawing in this specification, the same or similar reference symbols will be used for the same or similar components throughout the specification.

[0057] Furthermore, the size and thickness of each component shown in the drawings are arbitrarily shown for the convenience of explanation, and the present invention is not necessarily limited to those shown in the drawings. Thicknesses are exaggerated in the drawings to clearly show various layers and regions. In the drawings, the thicknesses of some layers and regions are exaggerated for the convenience of explanation.

[0058] Furthermore, the terms and words used in this specification and claims should not be interpreted in a limited way to their ordinary or dictionary meanings, but should be interpreted in a way that is consistent with the technical concept of the present invention, based on the principle that the inventor can appropriately define the concept of the term in order to best explain his or her invention.

[0059] Furthermore, throughout the specification, when a part "comprises" a certain element, this does not mean that other elements are excluded, and that other elements may also be included, unless otherwise specified to the contrary.

[0060] FIG. 1 is a flowchart showing a method for manufacturing a secondary battery according to an embodiment of the present invention.

[0061] 1 to 3, a method for manufacturing a secondary battery according to an embodiment of the present invention may include a basic unit manufacturing step, an electrode assembly manufacturing step, an initial cell manufacturing step, and a final cell manufacturing step.

[0062] Hereinafter, a method for manufacturing a secondary battery according to an embodiment of the present invention will be described, focusing on a step of manufacturing a basic unit and a step of manufacturing an electrode assembly.

[0063] 2 is a perspective view illustrating a step of manufacturing a radical unit in a method for manufacturing a secondary battery according to an embodiment of the present invention, and FIG. 3 is a front view illustrating a step of manufacturing a radical unit in a method for manufacturing a secondary battery according to an embodiment of the present invention.

[0064] First, in this embodiment, the radical unit 10 may be a laminated unit of an electrode and a separator 13. That is, an electrode and a separator 13 are sequentially laminated to form one radical unit 10, and stacking a plurality of such radical units 10 may form the electrode laminate 20 shown in FIG.

[0065] In the secondary battery manufacturing method according to this embodiment, the step of manufacturing a radical unit may be a step of manufacturing a radical unit 10 in which an adhesive 14 is applied to the surface of at least one of an electrode and a separator 13, and the electrode and the separator 13 are bonded to each other.

[0066] 2 and 3, the step of manufacturing the basic unit may include a step of unwinding a lower separator sheet 111 from a lower separator reel 110. Then, a step of applying adhesive 14 by a first nozzle 211 to at least a portion of one upward surface of the unwound lower separator sheet 111 may be included. The first nozzle 211 may apply the adhesive 14 in the form of a plurality of dots. A step of placing a first electrode 11 on the surface of the lower separator sheet 111 to which the adhesive 14 has been applied by the first nozzle 211 may then be performed. The first electrode 11 may be placed on one surface of the lower separator sheet 111 by cutting the first electrode 11 sheet unwound from a first electrode reel 11-1 to a predetermined size by a first cutter 221. The first electrode 11 and the lower separator may be bonded to each other by the adhesive 14 applied by the first nozzle 211.

[0067] 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 adhesive 14 by a second nozzle 212 to at least a portion of one surface of the unwound upper separator sheet 121 that contacts the first electrode 11 may be performed. The second nozzle 212 may apply the adhesive 14 in the form of a plurality of dots.

[0068] 2, after the second nozzle 212 applies the adhesive 14 to one side of the upper separation membrane sheet 121, one side and the other side of the upper separation membrane sheet 121 may be inverted. This is because the adhesive 14 is applied in a downward-dropping manner, but the side of the upper separation membrane sheet 121 that contacts the first electrode 11 faces downward to contact the first electrode 11, so the state when the adhesive 14 is applied and the state when it is bonded to the first electrode 11 may be inverted upside down.

[0069] After the upper separation membrane sheet 121 is turned upside down and bonded to the first electrode 11, a step of applying adhesive 14 by the third nozzle 213 to at least a portion of the other upward surface of the upper separation membrane sheet 121 may be performed. That is, the third nozzle 213 may apply adhesive 14 to the top of a stack in which the lower separation membrane sheet 111, the first electrode 11, and the upper separation membrane sheet 121 are stacked in this order from bottom to top. In this case, the third nozzle 213 may apply adhesive 14 in the form of a plurality of dots.

[0070] After the third nozzle 213 applies the adhesive 14, the step of manufacturing a basic unit in the method of manufacturing a secondary battery according to an embodiment of the present invention may include a step of placing a second electrode 12 on the other side of the upper separator sheet 121 on which the adhesive 14 is applied. The second electrode 12 may be formed by cutting the second electrode 12 sheet unwound from the second electrode reel 12-1 using the second cutter 222. This allows for a four-layer structure to be formed. That is, after the step of placing the second electrode 12, a four-layer laminate 130 can be formed by sequentially stacking the lower separator sheet 111, the first electrode 11, the upper separator sheet 121, and the second electrode 12.

[0071] 3, a step of applying pressure to the four-layer laminate 130 by rotating pressure nip rolls 230 disposed on the top and bottom surfaces of the four-layer laminate 130 may be further included. The pressure application step by the pressure nip rolls 230 can prevent any raised portions from forming in the four-layer laminate 130. This allows the electrodes and the separator 13 to be tightly bonded together.

[0072] 2 and 3, after the step of applying pressure to the four-layer laminate 130, a step of cutting the four-layer laminate 130 at regular intervals with a cutter to form the radical units 10 may be further included. This may involve cutting the upper separator sheet 121 and the lower separator sheet 111 located in the gaps between the electrodes with a third cutter 223 to manufacture the radical units 10.

[0073] In the method for manufacturing a secondary battery according to this embodiment, in the step of manufacturing a basic unit, when electrodes and separators are stacked to manufacture a unit cell (i.e., a basic unit), adhesive 14 is applied in advance each time the electrodes are placed on the separator sheets (lower separator sheet 111, upper separator sheet 121), thereby preventing the electrodes from being displaced without using an expensive separator.

[0074] In addition, since there is no need for a lamination process, the defect rate in the process caused by high heat and pressure can be reduced.Furthermore, since the laminator can be eliminated, the volume of the unit cell manufacturing equipment can be reduced and the manufacturing process can be simplified.

[0075] The separator according to the embodiments described herein may be a CCS (ceramic coated separator). Generally, a separator comprises a raw film and a coating layer formed on at least one surface of the raw film. The coating layer may contain alumina powder and a binder that binds them together. A safety reinforced separator (SRS) has a large amount of binder coated on the surface of the coating layer, but a CCS may not have a binder coated on the surface of the coating layer or may have a much lower binder content than an SRS. For example, in the case of a CCS separator according to the present embodiment, the binder content coated on the surface of the coating layer of the separator may be approximately 3 wt% or less.

[0076] When the separator is CCS, the internal electrodes included in the electrode assembly are transported in an unfixed state, which can lead to misalignment during transport. While the separator can be fixed using heat and pressure when the electrode and separator stack is formed, the internal electrodes may become misaligned during transport to a heat and pressure fixing device. Another drawback is that attaching the electrodes and separator using heat and pressure requires the use of expensive separators with high binder content. In contrast, this embodiment can prevent misalignment of the internal electrodes during transport and increase the fixing strength.

[0077] When the separator is a CCS, the electrolyte according to this embodiment may be a Gelyte electrolyte. The Gelyte electrolyte may include a gel-type electrolyte. In one embodiment, the Gelyte electrolyte physically binds a liquid solvent within the oligomer, suppressing volatilization and preventing flow, thereby preventing leakage. The oligomer included in the Gelyte electrolyte according to this embodiment may be fluorine-based, polycarbonate-based, or silicone-based. The use of fluorine-based oligomers enhances flame retardancy and acts as a scavenger for oxygen generated during decomposition of the cathode material due to heat generation, thereby suppressing additional heat generation. The use of polycarbonate-based oligomers has positive electrode affinity and a structure similar to that of organic electrolytes, resulting in excellent ionic conductivity. Furthermore, the use of silicone-based oligomers is advantageous for reducing gas emissions, and in particular, they act as a hydrofluoric acid scavenger (HF scavenger), improving the high-temperature storage environment.

[0078] If the electrodes and separator are not bonded using heat and pressure as in the past, the adhesive strength is weak, reducing cell rigidity and increasing the possibility of safety issues, but using a Gelrite electrolyte as in this example improves adhesive strength by at least 50% compared to when a liquid electrolyte is used, resulting in an increase in cell rigidity of approximately 40% or more compared to when a liquid electrolyte is used.Using SRS as the separator, the electrodes and separator are bonded during the lamination process, improving cell rigidity by approximately 19% or more compared to when a liquid electrolyte is used.

[0079] 4 is a cross-sectional view showing an electrode assembly 1 formed by stacking radical units 10 manufactured by the radical unit manufacturing step of a method for manufacturing a secondary battery according to an embodiment of the present invention. FIG. 5 is a cross-sectional view showing an electrode assembly formed by stacking radical units manufactured by the radical unit manufacturing step of a method for manufacturing a secondary battery according to another embodiment of the present invention.

[0080] 4, in the method for manufacturing a secondary battery according to this embodiment, the electrode assembly manufacturing step may be a step of manufacturing an electrode assembly 1 by attaching a fixing tape 50 around an electrode stack 20 formed by stacking a plurality of radical units 10. Here, the electrode assembly manufacturing step may be performed separately from the radical unit manufacturing step described above, or the electrode assembly manufacturing step may include the radical unit manufacturing step described above.

[0081] Within the basic unit 10, the electrodes (first electrode 11, second electrode 12) and the separator 13 are adhered to each other by an adhesive 14, and thus the alignment of the electrodes (first electrode 11, second electrode 12) and the separator 13 can be maintained by the adhesive force of the adhesive 14. The relative positions of the stacked basic units 10 can be fixed by the fixing tape 50 attached to the outside. In other words, the stacked alignment of the basic units 10 can be maintained by the fixing force of the fixing tape 50. For reference, the stack state before the fixing tape 50 is attached may be called an electrode stack 20, and the stack state after the fixing tape 50 is attached may be called an electrode assembly 1.

[0082] Furthermore, in the electrode assembly 1 manufactured in this embodiment, the adhesive 14 may be disposed at the same position between each electrode (first electrode 11, second electrode 12) and the separator 13. For example, as shown in FIG. 4, in the electrode assembly 1 of this embodiment, the adhesive 14 disposed between the lower part of the first electrode 11 and the separator 13 and the adhesive 14 disposed between the upper part of the first electrode 11 and the separator 13 may be disposed on the same vertical line based on the bottom surface, and the intervals between the adhesives 14 may be the same. This can be similarly explained for the adhesive 14 disposed between the second electrode 12 and the separator 13.

[0083] As a result, in the electrode assembly 1 manufactured in this embodiment, the adhesive 14 is disposed at the same position between each electrode (first electrode 11, second electrode 12) and the separator 13, which has the advantage of increasing process time and efficiency.

[0084] In addition, in an electrode assembly 2 manufactured using a method for manufacturing a secondary battery according to another embodiment of the present invention, adhesives 14 are disposed between each electrode (first electrode 11, second electrode 12) and separator 13, and adhesives 14 disposed in adjacent layers may be disposed in a crossed configuration. For example, as shown in FIG. 5, in the electrode assembly 2 of this embodiment, a first adhesive 14-1 disposed between the lower part of the first electrode 11 and separator 13 and a second adhesive 14-2 disposed between the upper part of the first electrode 11 and separator 13 may be disposed in a crossed configuration. In this case, the first adhesive 14-1 and the second adhesive 14-2 may be disposed at the same intervals, but may only be disposed in a crossed configuration. This can be similarly explained for the adhesive 14 disposed between the second electrode 12 and separator 13.

[0085] As an example, in the aforementioned basic unit manufacturing step, the first adhesive 14-1 and the second adhesive 14-2 may be arranged to intersect with each other by adjusting the position of at least one of the first nozzle 211, the second nozzle 212, and the third nozzle 213 shown in Figures 2 and 3.

[0086] As another example, in the above-described step of manufacturing the basic unit, a separate nozzle may be further disposed in addition to the first nozzle 211, the second nozzle 212, and the third nozzle 213, and the first adhesive 14-1 and the second adhesive 14-2 may be disposed so as to cross each other. More specifically, the separate nozzle may be disposed at a position different from the first nozzle 211, the second nozzle 212, and the third nozzle 213, and one of the first adhesive 14-1 and the second adhesive 14-2 may be dispensed 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 may be dispensed from the separate nozzle, and the first adhesive 14-1 and the second adhesive 14-2 may be disposed so as to cross each other.

[0087] However, the present invention is not limited to this, and the structure in which the first adhesive 14-1 and the second adhesive 14-2 are arranged to cross each other may be applied and manufactured in various ways.

[0088] As a result, in the electrode assembly 2 manufactured in this embodiment, adhesives 14 are disposed between each electrode (first electrode 11, second electrode 12) and separator 13, and the adhesives 14 disposed in adjacent layers are disposed in a crossed shape, thereby minimizing an increase in thickness of the electrode assembly 2 due to the adhesives 14. In addition, because the adhesives 14 disposed in adjacent layers are disposed in a crossed shape, the adhesives 14 can be more easily dissolved in the electrolyte contained in the initial cell 0 in FIG. 29, which will be described later.

[0089] Hereinafter, a method for manufacturing a secondary battery according to another embodiment of the present invention will be described, focusing on a step of manufacturing a basic unit and a step of manufacturing an electrode assembly.

[0090] 6 to 9 are schematic views showing steps of manufacturing a basic unit in a method of manufacturing a secondary battery according to another embodiment of the present invention.

[0091] First, in this embodiment, the radical unit 30 of Fig. 9 may be a unit in which the separator 322 is folded to cover the electrode 31, and the electrode 31 and the separator 322 are stacked together. That is, the radical unit 30 may be formed such that one side and the other side of the separator 322 are folded sequentially to cover the electrode 31, and the electrode 31 and the separator 322 are stacked sequentially. The electrode stack 40 of Fig. 10 can be manufactured by repeatedly forming such radical units 30 a plurality of times.

[0092] 6 to 9 , the method for manufacturing a secondary battery according to this embodiment includes the steps of unwinding electrode sheets 3111 and 3121 from electrode reels 311 and 312, forming a plurality of electrodes 31 from the electrode sheets 3111 and 3121, unwinding a separator 322 from the separator reel 321, forming a laminate with the electrode 31, placing the separator 322 on the upper surface of a table 36, and applying adhesive to at least a portion of the separator 322 and the electrode 31 placed on the table 36 using a nozzle 37. The electrode 31 includes a first electrode 3112 and a second electrode 3122. In this embodiment, the material unwound from the separator reel 321 is referred to as the separator 322, but as will be described later, it can also be seen as the separator sheet being folded to form each layer. Therefore, it can also be seen as the separator sheet being unwound from the separator reel 321.

[0093] 6, in the method of manufacturing a secondary battery according to this embodiment, when a first electrode sheet 3111 is unwound from a first electrode reel 311, a first cutter 331 may cut the first electrode sheet 3111 to form a plurality of first electrodes 3112. Next, when a first transfer device 341 transfers the first electrode 3112, a first header 351 adsorbs the first electrode 3112.

[0094] 6, when the separation membrane 322 is unwound from the separation membrane reel 321, the first region 3221 of the separation membrane 322 is placed on the upper surface of the table 36. Next, as shown in FIG. 6, the first nozzle 371 may apply adhesive to at least a portion of the first region 3221 of the separation membrane 322. Here, the first nozzle 371 may apply the adhesive in the form of a plurality of dots.

[0095] Next, the table 36 may move toward the first transfer device 341, and the first header 351 adsorbing the first electrode 3112 may move toward the table 36. However, this is not limited to this, 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 separation membrane 322 to which the adhesive is applied.

[0096] 6, adhesive may not be applied to the first region 3221 of the separation membrane 322, and adhesive may be applied in advance to the lower portion of the first electrode 3112. In other words, the first electrode 3112 may be placed on the first region 3221 of the separation membrane 322 by the first header 351 with adhesive applied in advance to the lower portion of the first electrode 3112.

[0097] In addition, the method for manufacturing a secondary battery according to this embodiment may further include a folding step after the adhesive application step, in which, when the first electrode 3112 is placed on the separator 322, one side of the separator 322 may be 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 may be folded to cover the second electrode 3122.

[0098] 7, after the first electrode 3112 is placed in 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 separation membrane 322 is folded, and the second region 3222 of the separation membrane 322 can cover the first electrode 3112. Here, before the first electrode 3112 is covered with the second region 3222 of the separation membrane 322, an adhesive may be applied in advance to the top of the first electrode 3112 or the second region 3222 of the separation membrane 322 by the first nozzle 371.

[0099] Meanwhile, when the second electrode sheet 3121 is unwound from the second electrode reel 312, the second cutter 332 may cut the second electrode sheet 3121 to form a plurality of second electrodes 3122. Next, when the second transport device 342 transports the second electrode 3122, the second header 352 adsorbs the second electrode 3122.

[0100] 7 and 8, when the second region 3222 of the separation membrane 322 covers the first electrode 3112, the second nozzle 372 positioned above the second region 3222 applies the adhesive to at least a portion of the second region 3222 of the separation membrane 322. Here, the second nozzle 372 may apply the adhesive in the form of a plurality of dots.

[0101] 8, the table 36 may move toward the second transfer device 342, and the second header 352 adsorbing the second electrode 3122 may move toward the table 36. However, this is not limited to this, and the table 36 may be fixed. When the second header 352 is positioned 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 separator 322 coated with adhesive.

[0102] 8, adhesive may not be applied to the second region 3222 of the separation membrane 322, and adhesive may be applied in advance to the lower portion of the second electrode 3122. In other words, with adhesive applied in advance to the lower portion 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.

[0103] 9, after the second electrode 3122 is placed in the second region 3222, the table 36 moves toward the first transfer device 341 that transfers the first electrode 3112. However, this is not limited to this, and the table 36 may be fixed. Then, the other side of the separation membrane 322 may be folded, and the first region 3221 of the separation membrane 322 may cover the second electrode 3122. Here, before the second electrode 3122 is covered with the first region 3221 of the separation membrane 322, an adhesive may be applied in advance to the top of the second electrode 3122 or the first region 3221 of the separation membrane 322 by the second nozzle 372.

[0104] 9, when the first region 3221 covers the second electrode 3122, the first nozzle 371 positioned above the first region 3221 applies adhesive to at least a portion of the first region 3221 of the separation membrane 322. Here, the first nozzle 371 may apply the adhesive in the form of a plurality of dots.

[0105] That is, by repeating the above process, a basic unit can be manufactured by the method for manufacturing a secondary battery according to this embodiment.

[0106] 10 is a cross-sectional view showing an electrode assembly manufactured by repeatedly forming radical units manufactured by the radical unit manufacturing step of a method for manufacturing a secondary battery in accordance with another embodiment of the present invention, and FIG. 11 is a cross-sectional view showing an electrode assembly manufactured by repeatedly forming radical units manufactured by the radical unit manufacturing step of a method for manufacturing a secondary battery in accordance with another embodiment of the present invention.

[0107] 10 , in the method for manufacturing a secondary battery according to this embodiment, the electrode assembly manufacturing step may be a step of manufacturing an electrode assembly 3 by attaching a fixing tape 50 around an electrode stack 40 formed with a plurality of repeated radical units 30, as in the electrode stack 20 of FIG. 4. Also, unlike the electrode assembly 1 of FIG. 4, the electrode assembly 3 may omit the fixing tape 50 as in FIG. 10. Also, instead of the fixing tape 50 of FIG. 4, the electrode assembly 3 may have one end of a separator 322 surrounding a portion of the outer surface of the electrode stack 40. Here, the electrode assembly manufacturing step may be performed separately from the radical unit manufacturing step described above, or the radical unit manufacturing step may be included in the electrode assembly manufacturing step.

[0108] 4, the radical unit 30 of this embodiment may have the electrodes (first electrode 3112, second electrode 3122) and the separation membrane 322 adhered to each other with the adhesive 34. As a result, the electrodes (first electrode 3112, second electrode 3122) and the separation membrane 322 can maintain their alignment due to the adhesive force of the adhesive 34.

[0109] In the electrode stack 40 of this embodiment, the separator 322 covers the top, bottom, and one side of the electrodes (first electrode 3112, second electrode 3122), and the stacked alignment of the radical units 30 can be maintained without a separate fixing tape 50 as shown in Fig. 4. Furthermore, when the fixing tape 50 of Fig. 4 is attached to the outside of the electrode stack 40 of this embodiment or when one end of the separator 322 is enclosed, the stacked alignment of the radical units 30 can be maintained more stably.

[0110] In addition, in the electrode assembly 3 manufactured in this embodiment, the adhesive 34 may be disposed at the same position between each electrode (first electrode 3112, second electrode 3122) and the separator 322. For example, as shown in Fig. 10, in the electrode assembly 3 of this embodiment, the adhesive 34 disposed between the lower part of the first electrode 3112 and the separator 322 and the adhesive 34 disposed between the upper part of the first electrode 3112 and the separator 322 may be disposed on the same vertical line based on the bottom surface of the first electrode 3112 or the separator 322, respectively, and the intervals at which the adhesives 34 are disposed may be the same. This can be similarly explained in the case of the adhesive 34 disposed between the second electrode 3122 and the separator 322.

[0111] As a result, in the electrode assembly 3 manufactured in this embodiment, the adhesive 34 is disposed at the same position between each electrode (first electrode 3112, second electrode 3122) and the separator 322, which has the advantage of increasing process time and efficiency.

[0112] In addition, in an electrode assembly 4 manufactured by a method for manufacturing a secondary battery according to another embodiment of the present invention, adhesives 34 are disposed between each electrode (first electrode 3112, second electrode 3122) and separator 322, and adhesives 34 disposed in adjacent layers may be disposed in a crossed configuration. For example, as shown in FIG. 11 , in the electrode assembly 4 of this embodiment, a first adhesive 34-1 disposed between the lower part of the first electrode 3112 and separator 322 and a second adhesive 34-2 disposed between the upper part of the first electrode 3112 and separator 322 may be disposed in a crossed configuration. In this case, the first adhesive 34-1 and the second adhesive 34-2 may be disposed at the same intervals, but may only be disposed in a crossed configuration. This can be similarly explained for the adhesive 14 disposed between the second electrode 3122 and separator 322.

[0113] For example, in the above-mentioned basic unit manufacturing step, the first adhesive 34-1 and the second adhesive 34-2 may be arranged to cross each other by adjusting the position of at least one of the first nozzle 371 and the second nozzle 372.

[0114] As another example, in the above-described step of manufacturing the basic unit, a separate nozzle may be further disposed in addition to the first nozzle 371 and the second nozzle 372, and the first adhesive 34-1 and the second adhesive 34-2 may be disposed so as to cross each other. More specifically, the separate nozzle may be disposed at a position different from the first nozzle 371 and the second nozzle 372, and one of the first adhesive 34-1 and the second adhesive 34-2 may be dispensed from the first nozzle 371 and the second nozzle 372, and the other of the first adhesive 34-1 and the second adhesive 34-2 may be dispensed from the separate nozzle, and the first adhesive 34-1 and the second adhesive 34-2 may be disposed so as to cross each other.

[0115] However, the present invention is not limited to this, and the structure in which the first adhesive 34-1 and the second adhesive 34-2 are arranged to cross each other may be applied and manufactured in various ways.

[0116] As a result, in the electrode assembly 4 manufactured in this embodiment, the adhesive 34 is disposed between each electrode (first electrode 3112, second electrode 3122) and the separator 322, and the adhesives 34 disposed in adjacent layers are disposed in a crossed shape, thereby minimizing an increase in the thickness of the electrode assembly 4 due to the adhesive 34. In addition, because the adhesives 34 disposed in adjacent layers are disposed in a crossed shape, the adhesives 34 can be more easily dissolved in the electrolyte contained in the initial cell 0 of FIG. 29, which will be described later.

[0117] The following description will focus on the basic units 10 and 30 described above.

[0118] 12 and 13 are exploded perspective views of a radical unit manufactured in a radical unit manufacturing step of a secondary battery manufacturing method in accordance with another embodiment of the present invention.

[0119] 12, the radical unit 10 may have a structure in which a separator 13, a first electrode 11, a separator 13, and a second electrode 12 are alternately stacked, as described with reference to FIGS. 2 to 5. Here, the separator 13 located below the first electrode 11 is called a lower separator, and the separator 13 located below the second electrode 12 is called an upper separator.

[0120] 6 to 11, the basic unit 30 may also have a structure in which the separation membrane 322 is folded to have a zigzag shape to cover the electrodes (first electrode 3112, second electrode 3122), and the first electrode 3112, the separation membrane 322, and the second electrode 3122 are alternately stacked. However, for the sake of convenience, the folded surface of the separation membrane 322 is not shown in FIG. 12.

[0121] In the basic unit 10, 30, a first electrode tap 11t, 3112t may be formed at one end of the first electrode 11, 3112, and a second electrode tap 12t, 3122t may be formed at one end of the second electrode 12, 3122. Here, the first electrode 11, 3112 and the second electrode 12, 3122 may be arranged such that the first electrode tap 11t, 3112t and the second electrode tap 12t, 3122t face in different directions.

[0122] Here, an adhesive layer (adhesive 14, 34) may be formed between the first electrode 11, 3112 and the separator 13, 322, and between the second electrode 12, 3122 and the separator 13, 322. As an example, the adhesive layer (adhesive 14, 34) may be formed by applying an adhesive in the form of multiple dots, as shown in FIG. 12. The multiple dots may be arranged at regular intervals. The adhesive layer (adhesive 14, 34) may also contain an adhesive component that dissolves in the electrolyte contained in the initial cell 0 of FIG. 29, which will be described later.

[0123] As a result, the adhesive layer (adhesive 14, 34) of the basic unit 10, 30 of this embodiment is arranged in a plurality of dots, and can be easily dissolved by the electrolyte. In addition, the adhesive layer (adhesive 14, 34) contains an adhesive component that dissolves in the electrolyte, and the adhesive layer (adhesive 14, 34) does not remain on the surfaces of the first electrode 11, 3112 and the second electrode 12, 3122 in the final battery cell, preventing a decrease in cell performance due to the adhesive layer (adhesive 14, 34).

[0124] Referring to FIG. 13, the basic units 10' and 30' can be described in much the same way as the basic units 10 and 30 of FIG. 12, and the following description will focus on the adhesive layers (adhesives 14 and 34).

[0125] In the basic unit 10', 30' according to this embodiment, the adhesive layer (adhesive 14, 34) may include a first adhesive layer 1410, 3410 and a second adhesive layer 1420, 3420. Here, the first adhesive layer 1410, 3410 may be located between the center of the first electrode 11, 3112 and the separator 13, 322, and between the center of the second electrode 12, 3122 and the separator 13, 322.

[0126] 13, the second adhesive layers 1420, 3420 may 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 layers 1420, 3420 may 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.

[0127] As another example, unlike FIG. 13, the second adhesive layers 1420, 3420 may be formed only in the portions where the first electrode taps 11t, 3112t and the separation membranes 13, 322 face each other between the first electrode taps 11t, 3112t and the separation membranes 13, 322, or may be formed only in the portions where the second electrode taps 12t, 3122t and the separation membranes 13, 322 face each other between the second electrode taps 12t, 3122t and the separation membranes 13, 322.

[0128] In this case, the first adhesive layers 1410, 3410 and the second adhesive layers 1420, 3420 may each be formed by applying adhesive in the form of multiple dots. The first adhesive layers 1410, 3410 may be formed of a first adhesive body, and the second adhesive layers 1420, 3420 may be formed of a second adhesive.

[0129] Here, the first adhesive forming the first adhesive layers 1410, 3410 may contain an adhesive component that dissolves in the electrolyte solution contained in the initial cell 0 of Fig. 29, as in the adhesive layers (adhesives 14, 34) of Fig. 12. In contrast, the second adhesive forming the second adhesive layers 1420, 3420 may contain an adhesive component that does not dissolve in the electrolyte solution.

[0130] For example, in the above-described step of manufacturing the basic unit, the first adhesive layers 1410, 3410 and the second adhesive layers 1420, 3420 may be formed by changing the type of adhesive applied from at least one of the nozzles 210 in Figures 2 and 3 or at least one of the nozzles 37 in Figures 6 to 9 during the manufacturing process. Specifically, the adhesives forming the first adhesive layers 1410, 3410 and the second adhesive layers 1420, 3420 may be applied through a single nozzle or through different nozzles.

[0131] As another example, in the step of manufacturing the basic unit, a separate nozzle may be further disposed in addition to the nozzle 210 of Figures 2 and 3 or the nozzle 37 of Figures 6 to 9, thereby forming the first adhesive layers 1410, 3410 and the second adhesive layers 1420, 3420, respectively. More specifically, the separate nozzle may be disposed adjacent to both ends of the separator 13, 322, and the first adhesive layers 1410, 3410 may be formed from the nozzle 210 of Figures 2 and 3 or the nozzle 37 of Figures 6 to 9, and the second adhesive layers 1420, 3420 may be formed from the separate nozzle.

[0132] However, the present invention is not limited thereto, and the first adhesive layers 1410 and 3410 and the second adhesive layers 1420 and 3420 may be formed by applying different adhesives in various ways.

[0133] As a result, in the basic unit bodies 10', 30' of this embodiment, the first adhesive layers 1410, 3410 are located between the center of the first electrode 11, 3112 and the separator 13, 322, and between the center of the second electrode 12, 3122 and the separator 13, 322, and the first adhesive layers 15, 35 do not remain on the surfaces of the first electrode 11, 3112 and the second electrode 12, 3122 in the final battery cell, thereby preventing a decrease in cell performance due to the first adhesive layers 1410, 3410.

[0134] In addition, in the radical units 10′ and 30′ of this embodiment, the second adhesive layers 1420 and 3420 are located between the first electrode tabs 11t and 3112t and the separators 13 and 322, and between the second electrode tabs 12t and 3122t, and the second adhesive layers 1420 and 3420 do not dissolve in the electrolyte in the final battery cell, thereby preventing the separators 13 and 322 facing the first electrode tabs 11t and 3112t and the second electrode tabs 12t and 3122t from folding. In addition, the second adhesive layers 1420 and 3420 can prevent the first electrodes 11 and 3112 and the second electrodes 12 and 3122 from separating from the separators 13 and 322 in the final battery cell.

[0135] Furthermore, the second adhesive layers 1420, 3420 may be located between a pair of facing separation membranes 13, 322, but may be formed in a portion excluding the portion where the separation membrane 13, 322 contacts the first electrode 11, 3112 and / or the second electrode 12, 3122. In other words, the second adhesive layers 1420, 3420 may be located between a pair of facing separation membranes 13, 322, but may not contact the first electrode 11, 3112 and the second electrode 12, 3122.

[0136] As a result, in the radical units 10′, 30′ of this embodiment, the second adhesive layers 1420, 3420 are formed at positions that avoid the contact between the first electrodes 11, 3112 and / or the second electrodes 12, 3122 and the separators 13, 322, and the second adhesive layers 1420, 3420 may not hinder the movement of lithium ions between the first electrodes 11, 3112 and / or the second electrodes 12, 3122 and the separators 13, 322. In other words, the second adhesive layers 1420, 3420 may prevent the separators 13, 322 from folding and the first electrodes 11, 3112 and the second electrodes 12, 3122 from separating from the separators 13, 322 without degrading cell performance.

[0137] Fig. 14 is an exploded perspective view of a radical unit according to another embodiment of the present invention, Fig. 15 is a perspective view showing an electrode assembly to which the components of Fig. 14 are combined, and Fig. 16 is a cross-sectional view taken along the AA axis of Fig. 15.

[0138] 14 and 15, the electrode assembly according to this embodiment includes a plurality of radical units, and each radical unit 109 according to this embodiment includes a first adhesive portion P1 formed between the electrodes (first electrode 119, second electrode 159) and the separators 219, 259 in the stacking direction of the electrodes (first electrode 119, second electrode 159) and the separators 219, 259, and a second adhesive portion P2 formed between adjacent separators 219, 259 in the stacking direction of the electrodes (first electrode 119, second electrode 159) and the separators 219, 259 among the plurality of separators 219, 259. The second adhesive portion P2 is located outside the first adhesive portion P1 in the stacking direction of the electrodes (first electrode 119, second electrode 159) and the separators 219, 259.

[0139] More specifically, the separation membranes 219, 259 include a lower separation membrane 219 and an upper separation membrane 259, and the electrodes 119, 159 include a first electrode 119 and a second electrode 159, and may be stacked in the order of the lower separation membrane 219, the first electrode 119, the upper separation membrane 259, and the second electrode 159.

[0140] Here, the first electrode 119 may include a first electrode tab 116 protruding in one direction, and the second electrode 159 may include a second electrode tab 155 protruding in one direction. For example, as shown in FIGS. 14 and 15 , the first electrode 119 and the second electrode 159 may be stacked such that an upper separation film 259 is positioned between them, and the first electrode tab 116 of the first electrode 119 and the second electrode tab 155 of the second electrode 159 are stacked in opposite directions. However, this is not limited thereto, and a structure in which the first electrode tab 116 and the second electrode tap 155 are stacked in the same direction may also be included in this embodiment. The outer side of the first adhesive portion P1 described above may be positioned in a direction intersecting the protruding direction of the electrode tabs (first electrode tab 116, second electrode tap 155).

[0141] Here, the first electrode 119 and the second electrode 159 may each include an electrode current collector and an active material layer disposed on the electrode current collector. Here, the active material layer may be made of an electrode composition including 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 may include a positive electrode current collector and an active material layer including a positive electrode active material, and the negative electrode may include a negative electrode current collector and an active material layer including a negative electrode active material. For example, the first electrode 119 may be a negative electrode, and the second electrode 159 may be a positive electrode. However, this is not limited thereto, and the opposite case may also be included in this embodiment.

[0142] The separators 219 and 259 may separate the first electrode 119 and the second electrode 159 and provide a path for lithium ions to move. The separators 219 and 259 may include a lower separator 219 and an upper separator 259, and the lower separator 219 and the upper separator 259 may be made of different or the same material.

[0143] For example, the separators 219 and 259 may be any separators that are normally used in lithium secondary batteries without any particular limitations, but as explained above, they may be CCS (Ceramic Coated Separators).

[0144] 14 and 16, the first adhesive portion P1 may be located at least one of between the first electrode 119 and the lower separation film 219, between the first electrode 119 and the upper separation film 259, and between the second electrode 159 and the upper separation film 259.

[0145] As a result, the first adhesive part P1 may fix the first electrode 119 and the second electrode 159 to the lower separation membrane 219 and / or the upper separation membrane 259, respectively. In other words, the first adhesive part P1 can prevent movement between the electrodes (first electrode 119, second electrode 159) and the separation membranes 219, 259, and can prevent deformation and damage of the electrodes (first electrode 119, second electrode 159) and the separation membranes 219, 259.

[0146] The second adhesive portion P2 may be located between the upper separation membrane 259 and the lower separation membrane 219. More specifically, the second adhesive portion P2 may be located between an end of the lower separation membrane 219 and an end of the first electrode 119. The second adhesive portion P2 may be located between an end of the upper separation membrane 259 and an end of the first electrode 119. In other words, the second adhesive portion P2 may be located on a surface of the separation membranes 219, 259 that does not contact the first electrode 119, and the second adhesive portion P2 may be located along the periphery of the first electrode 119. Here, the second adhesive portion P2 may also be selectively located in a portion where the electrode tabs (first electrode tab 116, second electrode tap 155) protruding from the electrodes (first electrode 119, second electrode 159) are located.

[0147] 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 part P2, preventing the first electrode 119 from moving between the upper separation membrane 259 and the lower separation membrane 219. In other words, the second adhesive part P2 fixes the upper separation membrane 259 and the lower separation membrane 219 to each other along the periphery of the first electrode 119, limiting the space in which the first electrode 119 can move, thereby preventing deformation and damage of the first electrode 119.

[0148] According to this embodiment, the first adhesive forming the first adhesive portion P1 and the second adhesive forming the second adhesive portion P2 may be different types from each other. Specifically, the first adhesive may be soluble in an electrolyte solution, and the second adhesive may be insoluble in an electrolyte solution.

[0149] 4, 5, 10, 11, 12, and 13 can be applied to the first adhesive forming the first adhesive portion P1 according to this embodiment. In addition, the above description of the separation membrane can also be applied to this embodiment.

[0150] 14 and 16, the first adhesive portion P1 and the second adhesive portion P2 may each be formed in a pattern including a plurality of dots. More specifically, the plurality of dots may be spaced apart from one another. Here, the intervals between the plurality of dots may be adjusted to be the same or different as necessary.

[0151] The second adhesive portion may be formed by applying adhesive partially along the longitudinal direction of the electrode assembly, which may be the same as the direction in which the electrode tabs (first electrode tab 116, second electrode tab 155) protrude.

[0152] As a result, the first adhesive portion P1 and the second adhesive portion P2 can be formed in the above-mentioned pattern, and after the electrode assembly including the basic unit body 109 is attached to a case to form a battery cell (secondary battery), when an electrolyte solution is injected into the case, the electrode assembly can be rapidly impregnated.

[0153] More specifically, the dots in the first adhesive portion P1 and the second adhesive portion P2 are spaced apart from one another, which has the advantage of allowing the electrolyte to flow between the dots. In other words, this embodiment can relatively shorten the manufacturing time of the battery cell and improve the yield. However, the adhesive pattern formed in the second adhesive portion P2 is not limited to a dot pattern, and may be formed in a spiral pattern as shown in FIG. 21. Furthermore, all of the details regarding the adhesive layers 145 and 145′ described below with reference to FIGS. 17 and 18 are applicable to the second adhesive forming the second adhesive portion P2 in this embodiment.

[0154] An electrode assembly according to another embodiment of the present invention will now be described.

[0155] 17 and 18 are views showing an electrode assembly according to another embodiment of the present invention.

[0156] 17 and 18, the electrode assembly 105 of this embodiment is a chargeable and dischargeable power generating element and may include electrodes (anode 115, cathode 125) and a separator 135. The electrodes 115, 125 included in the electrode assembly 105 may include a cathode 115 and an anode 125, and a separator 135 may be interposed between the electrodes 115, 125, so that the electrode assembly 105 may have a structure in which the cathode 115, the separator 135, and the anode 125 are alternately stacked. Here, the positions of the cathode 115 and the anode 125 shown in FIGS. 4 and 5 are shown for convenience, and their positions may be interchanged.

[0157] In addition, the electrode assembly 105 of this embodiment may include adhesive layers 145, 145' formed on its side surfaces. The electrode assembly 105 may include adhesive layers 145, 145' formed on the side surfaces of a cell stack in which the electrodes 115, 125 and the separators 135 are alternately stacked. Here, the term "cell stack" refers to the stack of the electrodes 115, 125 and the separators 135 in the electrode assembly 105 of this embodiment, and may not include the adhesive layers 145, 145'. In addition, the term "side surface of the cell stack" may refer to the exposed surface of the ends of the multiple electrodes (positive electrode 115, negative electrode 125) and / or separators 135 in the cell stack in which the electrodes (positive electrode 115, negative electrode 125) and the separators 135 are alternately stacked. When the electrode assembly 105 is manufactured, the size of the separator 135 may be larger than the size of the electrodes (positive electrode 115, negative electrode 125), and the ends of the separator 135 may protrude beyond the ends of the electrodes (positive electrode 115, negative electrode 125). In addition, as will be described later, when the electrode assembly 105 is stacked in a zigzag pattern, the folded portion of the separator 135 may protrude beyond the ends of the electrodes (positive electrode 115, negative electrode 125). Here, the protruding end of the separator 135 or the folded portion of the separator 135 may be referred to as an "extension 138."

[0158] The adhesive layers 145, 145' may be formed by applying an adhesive. The adhesive may contain a component that is not easily dissolved in the electrolyte. Examples of adhesives that can be used for the adhesive layers 145, 145' include PO, PUR, EVA, and rubber-based adhesives. Other examples include curable adhesives that can be cured by air curing, moisture curing, UV curing, etc.

[0159] The adhesive layers 145, 145′ may contact the extension 138 of the separator 135 that is not in contact with the electrodes (positive electrode 115, negative electrode 125), thereby fixing the shape of the separator 135. The separator 135 and another adjacent separator 135 may be fixed to each other by the adhesive layers 145, 145′.

[0160] The adhesive layers 145, 145' may be in contact with the separation membrane 135. In this case, the adhesive layer 145 may be formed between the separation membranes 135 so as to correspond to the position of the extension 138 of the separation membrane 135 as shown in Fig. 17, and the adhesive layer 145' may be formed to cover the outside of the extension 138 of the separation membrane 135 as shown in Fig. 18.

[0161] It is preferable that the adhesive layers 145, 145' do not contact the positive electrode 115. This is because the adhesive layers 145, 145' hinder the flow of ions moving from the positive electrode 115 to the negative electrode 125. In addition, it is preferable that the adhesive layers 145, 145' do not contact the negative electrode 125, but because the negative electrode 125 is not a direct charging area, this has less of an impact than contact between the positive electrode 115 and the adhesive layers 145, 145'.

[0162] The adhesive layers 145, 145' may be formed on all sides of the electrode assembly 105, but are preferably formed on only some sides. This is because if the adhesive layers 145, 145' are formed on all sides of the electrode assembly 105, the adhesive layers 145 would prevent gas from being released from the electrode assembly 105 during the electrolyte impregnation or activation process of the electrodes (positive electrode 115, negative electrode 125).

[0163] The adhesive layers 145, 145' may be formed to cover the entire side of the electrode assembly 105, or to cover 70 to 80% of the side. Here, the side of the electrode assembly 105 may have a "height" formed through lamination and a "width" corresponding to the length of the long or short side of the electrode assembly 105, and in this case, the adhesive layers 145, 145' may be formed to cover 70 to 80% of the width of the side of the electrode assembly 105. By not having the adhesive layers 145, 145' cover the entire side of the electrode assembly 105, it is possible to prevent the adhesive layers 145, 145' from interfering with gas release from the electrode assembly 105 during the electrolyte impregnation or activation process of the electrodes 115, 125.

[0164] The adhesive layers 145, 145' may be formed on the side of the electrode assembly 105 where the long side of the separator 135 is located. The adhesive layers 145, 145' may be formed on the long side of the separator 135. This is because folding tends to occur more frequently on the long side, which is longer than the short side of the separator 135. However, this does not completely exclude the possibility of forming the adhesive layers 145, 145' on the short side of the separator 135.

[0165] Figure 19 is a photograph of the side of the electrode assembly, and Figure 20 shows a test on the rigidity of the electrode assembly.

[0166] 19 and 20, the adhesive layers 145 and 145' can prevent the end of the separator 135 from folding over, and can enhance the rigidity of the electrode assembly 105.

[0167] Specifically, it was confirmed that the formation of adhesive layers 145, 145' on the sides of electrode assembly 105 improved the folding phenomenon that occurred in region A in Figure 2. Furthermore, in the same test as that shown in Figure 3, no sagging of a portion of electrode assembly 105 occurred in Figure 20, confirming that adhesive layers 145, 145' ensure the minimum rigidity required for electrode assembly 105. By supplementing the rigidity of electrode assembly 105 in this way, excessive deformation of electrode assembly 105 when an external force is applied can be prevented.

[0168] Fig. 21 is a diagram showing an example of an apparatus for applying adhesive to an electrode assembly and the adhesive applied, and Fig. 22 is a diagram showing another example of an apparatus for applying adhesive to an electrode assembly and the adhesive applied.

[0169] 21, the adhesive layers 145, 145′ of this embodiment may be formed in a patterned manner, where the adhesive 15 applied to the target position has a predetermined pattern.

[0170] The pattern-type adhesive applicator 205 may include a housing 215 and a nozzle 225. The adhesive 15 may be supplied from outside the adhesive applicator 205 and received in the housing 215, and the adhesive 15 may be dispensed linearly after passing through the nozzle 225. Specifically, the adhesive 15 discharged from the nozzle 225 may be connected like thin threads and applied in a wobble pattern. The applied adhesive 15 may have a specific pattern depending on the movement of the nozzle 225. As an example, the bottom of FIG. 21 shows a pattern shape in which multiple circles are overlapped by applying the adhesive 15 in a spiral shape. This pattern shape may be called a pigtail shape or a swirl pattern.

[0171] 22, the adhesive layers 145, 145′ of this embodiment may be formed by a surface application method, where the surface application method means that the adhesive is applied at a high density so that the adhesive 145′ is evenly distributed at the target position.

[0172] The surface-applying adhesive applicator 305 may apply adhesive 15' so that the adhesive 15' completely covers the target portion, as shown in the lower image of FIG. 22. The surface-applying adhesive applicator 305 may apply adhesive by spraying, slotting, or other methods. For example, the surface-applying adhesive applicator 305 may include a housing 315, a nozzle 325, a pipe 335 through which the adhesive 15 is supplied to the inside of the housing 315, and an air pipe 345 through which compressed air is injected when the adhesive 15 is sprayed through the nozzle 325 connected to the pipe 335.

[0173] On the other hand, the surface application type adhesive applicator 305 of Fig. 22 uses compressed air or the like, which may cause the adhesive 15' to splash when sprayed. Also, when attempting to form thick adhesive layers 145, 145', there is a disadvantage in that the uniformity of the adhesive layers 145, 145' is poor.

[0174] In contrast, the adhesive applicator 205 of Figure 21 dispenses adhesive 15 in a linear fashion, minimizing adhesive splashing caused by air and other factors, and thus minimizing contamination of the apparatus. Furthermore, the adhesive applicator 205 of Figure 21 allows for relatively flexible control of the density and thickness of adhesive layers 145, 145' by adjusting the spacing between the lines. By dispensing adhesive 15 in a consistent pattern, the adhesive applicator 205 of Figure 21 can dispense adhesive 15 more uniformly than the adhesive applicator 305 of Figure 22, even when thicker adhesive layers 145, 145' are to be formed.

[0175] The adhesive applicator 205 of Figure 21 can minimize the thickness of the adhesive layers 145, 145' compared to the adhesive applicator 305 of Figure 22. Specifically, the thickness of the adhesive layers 145, 145' formed by the adhesive applicator 205 of Figure 21 is approximately 100 μm or more, whereas the thickness of the adhesive layers 145, 145' formed by the adhesive applicator 305 of Figure 22 may be approximately 200 μm or more. This is because the adhesive applicator 205 of Figure 21 applies the adhesive 15 in a linear pattern, as described above.

[0176] The thickness of the adhesive layers 145, 145' formed on the electrode assembly 105 may be varied depending on the design. For example, the thickness of the adhesive layers 145, 145' may be designed to be less than the size of the gap between the electrode assembly 105 and the battery case inside the battery cell, taking into consideration the size of the gap. For example, when the electrode assembly 105 is installed in the battery case without the adhesive layers 145, 145' formed, the gap between the electrode assembly 105 and the battery case may be approximately 600 μm. In this case, the thickness of the adhesive layers 145, 145' formed on the electrode assembly 105 may be 600 μm or less, 500 μm or less, 400 μm or less, 300 μm or less, or 200 μm or less. The thickness of the adhesive layers 145, 145' formed on the electrode assembly 105 may be 100 to 600 μm, 100 to 500 μm, 100 to 400 μm, 100 to 300 μm, or 100 to 200 μm. In this case, the adhesive layers 145, 145' may be formed by repeatedly laminating lines using an adhesive applicator 205 shown in FIG.

[0177] The adhesive 15, 15' provided by the adhesive applicator may have a predetermined temperature. This is because the adhesive applicator controls the temperature of the adhesive 15, 15' so that the adhesive 15, 15' can be easily applied. The operating temperature of the adhesive applicator 205 of FIG. 21 is 110°C, and the temperature of the adhesive 15 dispensed from the adhesive applicator 205 may be between 40°C and 50°C. The operating temperature of the adhesive applicator 305 of FIG. 22 is 160°C, and the temperature of the adhesive 15' dispensed from the adhesive applicator 305 may be between 60°C and 70°C. Because a high temperature of the adhesive 15' is likely to cause shrinkage of the separator 135, it is preferable to use the adhesive applicator 205 of FIG. 21 rather than the adhesive applicator 305 of FIG. 22 to form the adhesive layers 145, 145' in this embodiment.

[0178] Figure 23 is a photograph comparing adhesives applied using the devices of Figures 21 and 22. Figure 24 is a magnified photograph of area B of Figure 23.

[0179] 23 and 24, the adhesive application shapes of the devices of Figures 21 and 22 can be compared. The shapes may be those of adhesive layers 145, 145' applied to the side surfaces of the electrode assembly 105.

[0180] 23(a) shows a patterned adhesive layer, which may be formed by the adhesive applicator 205 of FIG. 21. In FIG. 23(a), the adhesive 15 dispensed in a line shape is repeated in a spiral or circular shape to form a pattern. The adhesive layer 145, 145' formed by the patterned adhesive layer may have a pattern in which at least two lines intersect. The adhesive layer 145, 145' formed by the patterned adhesive layer may include a number of openings 88. The line width of the adhesive 15 formed by the patterned adhesive layer may be 20 to 100 μm, and the spacing between the lines may be 100 to 800 μm.

[0181] 24, it can be seen more clearly that the adhesive layers 145, 145' have a pigtail pattern. The first line width D1 measured from the photograph was found to be 50 μm, and the first line spacing W1 was found to be 600 μm.

[0182] In contrast, Figure 23(b) shows a surface application method, which may be formed by the adhesive application device 305 of Figure 22. In Figure 23(b), there are no gaps between the adhesive 15', and it is applied to form a single surface. In Figure 23(b), unlike Figure 23(a), no pattern formed by the intersection of at least two lines is observed, and it was confirmed that no openings are formed in the adhesive layers 145, 145'.

[0183] Meanwhile, since the adhesive layers 145, 145' in this embodiment are formed on the sides of the electrode assembly 105, the adhesive layers 145, 145' may prevent the electrodes (cathode 115, anode 125) from contacting the electrolyte solution absorbed through the sides of the electrode assembly 105. Therefore, the adhesive layers 145, 145' should be formed in a manner that minimizes the decrease in electrolyte absorption.

[0184] FIG. 25 is a photograph of a wettability test of an electrode assembly using the processes of FIGS. 21 and 22. Specifically, FIG. 25 shows an electrode assembly 105 having adhesive layers 145 and 145′ formed through the processes of FIGS. 21 and 22, which was immersed in an electrolyte solution and then disassembled. The photograph shows non-wetting regions 25, which represent areas of the electrodes (positive electrode 115 and negative electrode 125) that have not absorbed the electrolyte solution. Based on this, it can be determined whether the adhesive layers 145 and 145′ reduce the wettability of the electrodes (positive electrode 115 and negative electrode 125) to the electrolyte solution. Here, a smaller non-wetting region 25 indicates more sufficient contact between the electrodes (positive electrode 115 and negative electrode 125) and the electrolyte solution.

[0185] 25, it can be seen that the electrode of Fig. 25(a), which was formed using the patterning method of Fig. 21, has a smaller non-wetting area 25 than the electrode of Fig. 25(b), which was formed using the surface coating method of Fig. 22. In other words, the adhesive layers 145, 145' formed according to Fig. 21 may not hinder the absorption of electrolyte as much as the adhesive layers 145, 145' formed according to Fig. 22.

[0186] The pattern coating method of Figure 21 has a pattern in which many lines intersect, and therefore many openings may be formed in the adhesive layers 145, 145' of Figures 17 and 18. When the electrode assembly 105 is immersed in an electrolyte, the electrolyte may be absorbed into the electrode assembly 105 through the openings. Therefore, adhesive layers 145, 145' formed by the pattern coating method can minimize the decrease in electrolyte penetration compared to adhesive layers 145, 145' formed by the surface coating method.

[0187] If the electrolyte is not properly absorbed by the electrodes (positive electrode 115, negative electrode 125), the output characteristics of the electrode assembly 105 may be reduced. Therefore, even when forming the adhesive layers 145, 145' using the surface coating method of Fig. 22, the absorption rate of the electrolyte can be increased by partially forming the adhesive layers 145, 145' on the sides of the electrode assembly 105. However, when the adhesive layers 145, 145' are partially formed in this manner, the rigidity of the electrode assembly 105 may be reduced, as shown in Fig. 3, so the application position and application level of the adhesive layers 145, 145' must be more strictly designed.

[0188] An electrode assembly according to another embodiment of the present invention will now be described.

[0189] Prior to the description, it should be made clear that the electrode assembly of this embodiment is identical to the above-described electrode assemblies except for the shape of the cell stack. Therefore, unless otherwise specified, the electrode assembly of this embodiment can be considered to include all of the details related to the electrode assemblies of Figures 17 to 25.

[0190] 26 and 27 are views showing an electrode assembly according to another embodiment of the present invention.

[0191] 26 and 27, the electrode assembly 105 of this embodiment may include a cell stack in which positive electrodes 115, separators 135, and negative electrodes 125 are alternately stacked, and finishing separators 132 and 134 surrounding the sides of the cell stack. Here, the separator 135 has a zigzag shape formed by folding a rectangular separator sheet, and the zigzag-folded separator 135 may be interposed between the positive electrodes 115 and the negative electrodes 125. After the zigzag stacking is completed, the separator 135 may surround the sides of the cell stack at least once via the finishing separators 132 and 134, thereby finishing the sides of the cell stack.

[0192] 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 the positions may be interchanged.

[0193] Adhesive layers 145, 145' may be formed on the side surfaces of the cell stack. The adhesive layers 145, 145' may contact the extensions 138 of the separation membrane 135 and connect the extensions 138 to fix the shape of the separation membrane 135. The adhesive layers 145, 145' may connect the folded portions of the separation membrane 135, i.e., the folded portions of the separation membrane 135, to fix the overall shape of the separation membrane 135. The adhesive layers 145, 145' may fix the overall shape of the cell stack including the separation membrane 135 and ensure minimum rigidity.

[0194] The adhesive layers 145, 145' may be formed on all sides of the cell stack as described above, or on both sides where the folded separator 135 is located, as shown in FIGS. 26 and 27. Also, unlike FIGS. 26 and 27, they may be formed on the other side of the cell stack. However, because the adhesive layers 145, 145' may prevent gas release from the electrode assembly 105 during the electrolyte impregnation or activation process of the electrodes (cathode 115, anode 125), the positions of the adhesive layers 145, 145' must be appropriately designed, and it is not preferable for them to be formed to cover all sides of the cell stack. The adhesive layers 145, 145' may be formed to cover the entire side of the electrode assembly 105, or to cover 70 to 80% of the side.

[0195] After adhesive layers 145, 145' are formed on the cell stack, finishing separation membranes 132, 134 may be formed on the outer surfaces of the adhesive layers 145, 145'. The finishing separation membranes 132, 134 may surround the side surfaces of the cell stack on which the adhesive layers 145, 145' are formed. In this case, the finishing separation membrane 132 may be wrapped once around the entire cell stack, as shown in FIG. 26, to finish the side surfaces of the cell stack. Alternatively, the finishing separation membranes 132, 134 may be wrapped twice or more around the cell stack, as shown in FIG. 27, to finish the side surfaces of the cell stack.

[0196] Meanwhile, even if the finishing separators 132 and 134 are not formed in the electrode assembly 105, the sides of the cell stack can be finished by attaching an adhesive means such as heat sealing or adhesive tape, and the finishing method can be varied in many ways in addition to the above-mentioned embodiments.

[0197] A method for manufacturing an electrode assembly according to an embodiment of the present invention will now be described.

[0198] The manufacturing method S1000 of the electrode assembly of this embodiment may include step S1100 of forming a cell stack in which electrodes (positive electrode 115, negative electrode 125) and separators 135 are alternately stacked, step S1200 of applying adhesive 15 to the side of the cell stack, and step S1300 of forming adhesive layers 145, 145' that fix the separator 135.

[0199] Here, step S1100 of forming the cell stack may be performed using any known method as long as it stacks the electrodes and the separation membranes in the order of positive electrode 115, separation membrane 135, negative electrode 125, and separation membrane 135, or in the order of negative electrode 125, separation membrane 135, positive electrode 115, and separation membrane 135. For example, the cell stack may be manufactured in a stacked form as shown in Figures 17 and 18, or in a zigzag form as shown in Figures 26 and 27.

[0200] Here, step S1200 of applying adhesive to the side surfaces of the cell stack may use adhesive applicator 205 of Fig. 21 or adhesive applicator 305 of Fig. 22. When adhesive applicator 205 of Fig. 21 is used, step S1200 may include a step of determining an application pattern for adhesive 15 and / or a step of applying the adhesive in a pattern by moving nozzle 225 in the determined pattern. Here, the step of determining the application pattern for adhesive 15 may be performed before step S1100 of forming the cell stack.

[0201] Since the adhesive 15 is applied in a viscous state, it is preferable to fix the shape of the adhesive 15 by removing the solvent or moisture in the adhesive. In such a case, step S1300 of forming the adhesive layers 145, 145' may include a step of drying the adhesive 15. Furthermore, depending on the inherent properties of the adhesive 15, the adhesive 15 may be hardened by thermal curing or UV curing. In such a case, step S1300 of forming the adhesive layers 145, 145' may include a step of hardening the adhesive 15.

[0202] Meanwhile, when this embodiment is a method for manufacturing the zigzag-type electrode assembly 105 shown in FIGS. 26 and 27, the manufacturing method may further include step S1400 of finishing the side surfaces of the cell stack. Through this step, finishing separation membranes 132, 134 may be formed on the side surfaces of the cell stack. The finishing separation membranes 132, 134 may be finished after wrapping the side surfaces of the cell stack at least once. The finishing separation membranes 132, 134 may be wrapped around the side surfaces of the cell stack once, as shown in FIG. 26, or may be wrapped around the side surfaces of the cell stack two or more times, as shown in FIG. 27.

[0203] Meanwhile, the electrode assembly 105 of this embodiment described above may be housed in a cell case together with an electrolyte and provided in a secondary battery, that is, a battery cell.

[0204] 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 separators are alternately stacked, electrode leads connected to electrode taps extending from the plurality of electrodes, and a cell case that seals the electrode assembly with one end of the electrode lead protruding.

[0205] The battery cells may be stacked in one direction to form a battery cell stack, or may be modularized into battery modules to form a battery pack together with a Battery Management System (BMS) that manages the temperature and voltage of the battery and / or a cooling device. The battery pack may be applied to a variety of devices. For example, the device to which the battery pack is applied may be a means of transportation such as an electric bicycle, an electric vehicle, or a hybrid vehicle. However, the device is not limited thereto, and the battery pack according to this embodiment may be used in various devices other than the above examples, and this also falls within the scope of the present invention.

[0206] Fig. 28 is a perspective view showing an initial cell manufacturing step in a method for manufacturing a secondary battery according to another embodiment of the present invention, and Fig. 29 is a front view showing a formation step in a method for manufacturing a secondary battery according to another embodiment of the present invention.

[0207] Referring to FIG. 28, the method for manufacturing a secondary battery according to this embodiment may include a step of manufacturing an initial cell after the step of manufacturing an electrode assembly.

[0208] The initial cell manufacturing step may be a step of housing the electrode assemblies 1, 2, 3, and 4 in a pouch case 70, injecting an electrolyte into the pouch case 70, and then sealing an edge 71 of the pouch case to manufacture the initial cell 0 shown in FIG. 29. The pouch case 70 may include a gas pocket portion 75 extending to one side of a cup portion 74 in which the electrode assemblies 1, 2, 3, and 4 are housed. After the electrode assemblies 1, 2, 3, and 4 and the electrolyte are housed in the cup portion, the edge 71 of the pouch case may be sealed.

[0209] In this case, sealing is performed at the edge of the cup portion 74 and the outer edge of the gas pocket portion 75. That is, the edge of the area where the cup portion 74 and the gas pocket portion 75 are combined can be sealed so that it forms a closed curve, and the area where the cup portion 74 and the gas pocket portion 75 are combined can be sealed so that it is hermetically sealed from the outside. That is, the cup portion 74 and the gas pocket portion 75 have a structure that is isolated from the outside, but can communicate with each other after sealing.

[0210] 29 is manufactured in a sealed state, a step of manufacturing a final cell by post-processing the initial cell 0 may be performed. In the final cell manufacturing step, the adhesive applied to the surface of at least one of the electrodes and the separator 13, 322 in the previous step of manufacturing the basic unit may be dissolved. The electrolyte contained in the initial cell 0 may be an organic solvent, and the dissolution of the adhesives 14, 34 means that the adhesives 14, 34 dissolve in the electrolyte, which is an organic solvent.

[0211] This means that the area of ​​the adhesive 14, 34 that was applied to the surface of the electrode or separator 13, 322 is reduced, or the applied adhesive 14, 34 is completely removed.

[0212] In the case of the electrodes 11, 12, and 31, this means that the adhesives 14 and 34 do not remain on the surfaces of the electrodes.

[0213] Furthermore, in the case of the separator 13, 322, because the separator 13, 322 is generally a porous sheet, a portion of the adhesive 14, 34 may permeate the separator 13, 322. In this case, in the final cell manufacturing step described above, the adhesive 14, 34 that has permeated the separator 13, 322 may dissolve in the electrolyte, and during this process, traces of the adhesive 14, 34 may remain on the separator 13, 322.

[0214] Here, the application trace of the adhesive 14, 34 means that the components of the adhesive 14, 34 do not remain, but a part of the outer surface of the separation membrane 13, 322 is deformed by the adhesive 14, 34. However, it is not limited thereto, and the application trace of the adhesive 14, 34 means a trace that can be visually confirmed as to whether the adhesive 14, 34 has been applied, or a trace that can be confirmed in various ways as to whether the adhesive 14, 34 has been applied.

[0215] As a result, traces of the adhesive 14, 34 formed on the separation membrane 13, 322 may be formed at the same positions as the positions where the adhesive 14, 34 was applied.

[0216] In particular, the adhesives 14 and 34 for bonding the electrodes and the separator used in the method for manufacturing a secondary battery according to this embodiment may be acrylate adhesives, which allow the adhesives 14 and 34 to dissolve in the electrolyte.

[0217] In the method for manufacturing a secondary battery according to this embodiment, the final cell manufacturing step may include a formation process in which the initial cell 0 is activated by charging it at a temperature higher than room temperature. The formation process (activation process) is a process in which an SEI layer is formed on the surface of the electrode plate of the electrode assembly through a charging process, thereby allowing the secondary battery to be formed to supply power.

[0218] In the final cell manufacturing step, the formation process may be performed at a temperature of 45 degrees Celsius or higher. The adhesives 14, 34 may be at least partially melted during the formation process. More preferably, in the final cell manufacturing step, the formation process may be performed at a temperature between 50 and 70 degrees Celsius. At temperatures higher than 45 degrees, i.e., 50 degrees or higher, the adhesive 14 is more likely to melt. At temperatures higher than 70 degrees Celsius, the performance of the cell product may be reduced, which is undesirable.

[0219] 29, in the final cell manufacturing step of the secondary battery manufacturing method according to this embodiment, the formation process may include a jig pressurizing process in which both sides of the initial cell 0 are pressed using a jig 500. The left side of the initial cell 0 may be pressed using a left jig 510, and the right side of the initial cell 0 may be pressed using a right jig 520. When the initial cell 0 is pressed using the jig 500, gas generated inside the electrode assemblies 1, 2, 3, and 4 can be smoothly transferred to the gas pocket 75 shown in FIG. 29. The gas transferred to the gas pocket 75 can be smoothly discharged to the outside of the cell in a subsequent degassing process. Performing the jig pressurizing process during the formation process facilitates the dissolution of the adhesives 14 and 34 into the electrolyte.

[0220] Here, the jig pressurizing process may include a process of applying or releasing pressure from the jig 500 that presses both sides of the initial cell 0. That is, one cycle of applying or releasing pressure from the jig 500 to press the initial cell 0 may be repeated at least twice.

[0221] The one cycle of applying and releasing pressure by the jig 500 may be a process of directly applying physical force by alternately applying positive and negative pressure to the adhesive 14, 34 while it is being dissolved, thereby significantly increasing the likelihood of the adhesive 14, 34 dissolving.

[0222] In this case, a control device may be connected to the jig device for more systematic operation, thereby adjusting the time for applying positive pressure and the time for applying negative pressure, and also controlling the magnitude of the positive pressure and the negative pressure, thereby realizing a more effective adhesive dissolving system.

[0223] In particular, in the final cell manufacturing step of the secondary battery manufacturing method according to the embodiment of the present invention, the formation process is performed at a temperature between 55°C and 65°C, and may include a jig pressing process of pressing both sides of the initial cell 0 using a jig 500. In this case, the adhesives 14, 34 may be completely dissolved in the formation process, and no adhesives 14, 34 may remain on the surfaces of the electrodes. Also, as described above, traces of the adhesives 14, 34 may remain on the separators 13, 322.

[0224] If the adhesives 14, 34 remain on the surface of the electrode, the area where the adhesives 14, 34 remain may become an unreacted area where an electrode reaction does not occur, which may result in a decrease in battery performance. However, if the adhesives 14, 34 are completely dissolved and removed from the surface of the electrode and / or separator 13, 322 as in the present invention, the unreacted area due to the adhesives 14, 34 disappears, preventing a decrease in performance and achieving excellent battery performance.

[0225] Meanwhile, the final cell manufacturing step of the secondary battery manufacturing method according to this embodiment may 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 may be performed for about 1.5 days. The pre-aging process may be a process that provides time for the electrolyte to sufficiently penetrate between the electrodes and the separators 13, 322. Of course, the adhesives 14, 34 may also be at least partially dissolved during the pre-aging process.

[0226] When the electrolyte according to this embodiment is a gellite electrolyte, the method for manufacturing a secondary battery according to this embodiment may further include a pre-charging step (see FIG. 31) before the pre-aging step, as shown in FIG. 31. For example, charging may be performed up to 1.7 V at a current of 0.05 C. The pre-charging step may also be performed after the pre-aging step.

[0227] In addition, the final cell manufacturing step of the secondary battery manufacturing method according to this embodiment may further include a room temperature aging step of storing the initial cell O at room temperature after the formation step. The room temperature aging step may be performed for about one day. In addition, the final cell manufacturing step may further include a high temperature aging step of storing the initial cell O at a temperature of 60 to 65 degrees Celsius after the room temperature aging step and before the degassing step. Here, the order of the room temperature aging step and the high temperature aging step may be reversed.

[0228] Furthermore, the final cell manufacturing step 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 internal gas of the initial cell 0 to the outside. The gas discharged in the degassing process is mainly internal gas generated in the formation process and stored in the gas pocket portion 75. In the degassing process, through-holes may be formed in the gas pocket portion 75 so that the gas can be discharged to the outside.

[0229] The final cell manufacturing step may include a resealing process in which the initial cell 0 is resealed after the degassing process so that it is again sealed from the outside. This allows the final cell to be manufactured. The adhesives 14 and 34 may be dissolved and no longer remain on the surfaces of the internal electrodes or separators 13 and 322 of the final cell manufactured in this manner. In particular, as described above, no traces of the adhesives 14 and 34 may remain on the separators 13 and 322.

[0230] Meanwhile, the method for manufacturing a secondary battery according to this embodiment may further include a final charge-discharge step of charging and discharging the final cell after the final cell manufacturing step. The final charge-discharge step may include a step of measuring the battery capacity of the final cell and a step of final charging the battery to a set voltage for shipping the final product.

[0231] When the electrolyte solution according to this embodiment is a gellite electrolyte solution, the method for manufacturing a secondary battery according to this embodiment may further include a step of curing at 60 to 65 degrees Celsius for approximately 5 hours (see FIG. 31) before the formation process. The liquid electrolyte solution can be hardened into a gel through the curing process. Furthermore, jig curing is preferably performed to harden the electrolyte solution uniformly within the electrode. The jig curing process hardens the electrolyte solution uniformly within the electrode by hardening the electrolyte solution while applying uniform pressure to both sides of the battery cell. This is because the jig curing process allows the electrolyte solution to be uniformly distributed within the electrode.

[0232] The present invention will be described below through more specific experimental examples. However, the following experimental examples are provided to exemplify the present invention and are not intended to limit the scope of the present invention.

[0233] <Experimental example - Checking adhesive marks> A battery cell was fabricated containing an electrode assembly in which positive electrodes, negative electrodes, and separators were alternately stacked, and an electrolyte. Adhesive dots were applied between the positive electrode and the separator and between the negative electrode and the separator. The separator was a ceramic coated separator (CCS), the adhesive included an acrylate adhesive, and the electrolyte was a standard electrolyte solution in which EC (ethylene carbonate) and EMC (ethyl methyl carbonate) were mixed in a ratio of 3:7.

[0234] Next, the fabricated battery cell was charged, and the separator was separated from the charged battery cell. The separated separator was washed with acetone and dried to remove the electrolyte absorbed in the separated separator, and the surface of the separator was then observed. The results are shown in Figure 30. Figure 30(a) is an image observed visually, and Figure 30(b) is an image photographed under a microscope.

[0235] <Analysis of Experimental Results - Confirmation of Adhesive Application Marks> 30(a) and (b), it can be seen that the adhesive leaves marks on the separator when the separator is separated from a charged battery cell. In particular, when the separator is magnified with a microscope as in FIG. 30(b), it can be seen that the adhesive marks left on the separator are more easily observed.

[0236] In other words, in the battery cell according to this embodiment, the adhesive application marks left on the outer surface of the separator confirm that adhesive was applied between the positive electrode and the separator and between the negative electrode and the separator in the electrode assembly unit.

[0237] Although the present invention has been described above using limited examples and drawings, the present invention is not limited thereto, and various implementations are possible within the technical spirit of the present invention and the scope of the claims set forth below by a person having ordinary skill in the art to which the present invention pertains. [Explanation of symbols]

[0238] 0: Initial cell 1, 2, 3, 4: Electrode assembly 70: Pouch case 71: Pouch case edge 75: Gas pocket 10, 30: Basic unit 11, 119, 3112: 1st electrode 11-1, 311: First electrode reel 12, 159, 3122: 2nd electrode 12-1, 312: Second electrode reel 13, 322: Separation membrane 14, 15, 15', 34: Adhesive 20, 40: Electrode laminate 50: Fixing tape 60: Electrode lead 110: Lower separation membrane reel 111: Lower separation membrane sheet 120: Upper separation membrane reel 121: Upper separation membrane sheet 130: 4-layer laminate 138: Extension part 205, 305: adhesive application device 210, 371: Nozzle 211, 371: No. 1 nozzle 212, 372: Second nozzle 213: 3rd nozzle 221, 331: First cutter 222, 332: Second cutter 223: Third Cutter 230: Pressure nip roll 341, 342: 1st and 2nd transfer device 500: Jig 510: Left side jig 520: Right side jig P1, P2: 1st and 2 adhesive parts

Claims

1. an electrode assembly manufacturing step of manufacturing an electrode assembly in which the electrodes and the separators are fixed to each other by an adhesive so that the electrodes and the separators are alternately stacked; a battery cell manufacturing step of housing the electrode assembly together with an electrolyte in a pouch case and sealing the pouch case to manufacture a battery cell; the step of manufacturing the electrode assembly includes forming a first adhesive portion between the electrode and the separator, and a second adhesive portion between adjacent separators among a plurality of separators included in the electrode assembly; the second adhesive portion is formed to be disposed outside the first adhesive portion in a direction perpendicular to a direction in which the electrode and the separator are stacked, At least a part of a first adhesive forming the first adhesive portion is soluble in the electrolyte solution, and a second adhesive forming the second adhesive portion is insoluble in the electrolyte solution. Secondary battery manufacturing method.

2. The method of manufacturing a secondary battery according to claim 1 , wherein a first adhesive forming the first adhesive portion and a second adhesive forming the second adhesive portion are different in type from each other.

3. The method of manufacturing a secondary battery according to claim 2 , wherein at least a portion of the first adhesive forms an adhesive mark on the separator.

4. The method of claim 1 , wherein the first adhesive portion is formed to include adhesive patterns disposed at the same positions between the electrodes and the separators.

5. The method of claim 1 , wherein the first adhesive portion is formed to include adhesive patterns that are alternately arranged between the electrodes and the separators.

6. The method of manufacturing a secondary battery 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 pattern.

7. The method of manufacturing a secondary battery according to claim 6 , wherein the first adhesive portion is formed by applying the adhesive in a dot pattern.

8. The method of manufacturing a secondary battery according to claim 6 , wherein the second adhesive portion is formed of an adhesive layer having a plurality of openings.

9. 10. The method of claim 1, wherein the separator is formed in a zigzag shape by folding a rectangular separator sheet.

10. the separation membrane has opposing long sides and opposing short sides; The method of manufacturing a secondary battery according to claim 9 , wherein the adhesive layer forming the second adhesive portion is formed along the long side of the separator.

11. the adhesive layer forming the second adhesive portion is formed by applying the second adhesive in a wobble pattern; The method of manufacturing a secondary battery according to claim 10 , wherein the wobble pattern has a pattern shape in which two lines intersect.

12. The manufacturing step of the battery cell further includes a formation process of activating the battery cell by charging it at a temperature higher than room temperature, The method for manufacturing a secondary battery according to claim 1 , wherein at least a portion of the first adhesive dissolves in the electrolyte solution in the formation process.

13. The method of manufacturing a secondary battery according to claim 12, wherein the formation process is performed at a temperature of 50°C to 70°C.

14. The method of manufacturing a secondary battery according to claim 13 , wherein the formation step includes a jig pressing step of pressing both side surfaces of the initial cell using a jig.

15. The formation step is carried out at a temperature of 55°C or more and 65°C or less, The method of manufacturing a secondary battery according to claim 14 , wherein the first adhesive is completely dissolved in the electrolyte solution during the formation process, and the adhesive located on the surface of the electrode is removed.

16. The method of manufacturing a secondary battery according to claim 12, wherein the manufacturing step of the battery cell further comprises a pre-charging step.

17. The method of manufacturing a secondary battery according to claim 12 , wherein the step of manufacturing the battery cell further comprises a step of curing before the formation process.

18. the first adhesive and the second adhesive are acrylate adhesives, The method for manufacturing a secondary battery according to claim 1 , wherein the electrolytic solution is an organic solvent.

19. The method further includes a step of manufacturing a radical unit, which is a laminated unit of the electrode and the separator, 2. The method of claim 1, wherein the electrode assembly is manufactured by attaching a fixing tape around an electrode stack formed by stacking a plurality of the radical units.

20. The step of manufacturing the basic unit body includes: a step of unwinding the lower separation membrane from the lower separation membrane reel; applying one of the first adhesive and the second adhesive to at least a portion of an upwardly facing surface of the unwound lower separation film using a first nozzle; placing a first electrode on one surface of the lower separation membrane on which one of the first adhesive and the second adhesive is applied; unwinding the upper separation membrane from the upper separation membrane reel; a second nozzle applying one of the first adhesive and the second adhesive to at least a portion of a surface of the unwound upper separation film that contacts the first electrode; a third nozzle applying one of the first adhesive and the second adhesive to at least a portion of the other upwardly facing surface of the upper separation film; 20. The method of claim 19, further comprising: after a third nozzle applies one of the first adhesive and the second adhesive, placing a second electrode on the other surface of the upper separator on which the adhesive is applied.

21. 21. The method of claim 20, wherein the first nozzle, the second nozzle, and the third nozzle apply one of the first adhesive and the second adhesive in a plurality of dots.

22. The separator is folded to cover the electrode, and the method further includes manufacturing a radical unit in which the electrode and the separator are stacked, The method of manufacturing a secondary battery according to claim 1 , wherein the electrode assembly is manufactured by repeatedly forming the basic unit bodies.

23. The step of manufacturing the basic unit body includes: unwinding an electrode sheet from an electrode reel and forming a plurality of electrodes from the electrode sheet; unwinding the separation membrane laminated with the electrode from a separation membrane reel; placing the separation membrane on an upper surface of a table; a step of applying the first adhesive and the second adhesive to at least a portion of the separation membrane and the electrode placed on the table using a nozzle; The method of manufacturing a secondary battery according to claim 22 , wherein the electrodes include a first electrode and a second electrode.

24. The method further includes a folding step after the step of applying the first adhesive and the second adhesive, The folding step comprises: When the first electrode is placed on the separator, one side of the separator is folded to cover the first electrode; The method of claim 23, wherein when the second electrode is placed on the separator, the other side of the separator is folded to cover the second electrode.

25. The method of claim 23 , wherein the nozzle applies the first adhesive and the second adhesive in a plurality of dots.

26. The method for manufacturing a secondary battery according to claim 1 , wherein the electrolytic solution is a gel-type electrolytic solution.

27. The method of manufacturing a secondary battery according to claim 26, wherein the electrolyte solution contains a fluorine-based, polycarbonate-based, or silicon-based oligomer.

28. An apparatus for manufacturing a secondary battery including an electrode assembly formed by alternately stacking electrodes and separators, an electrode reel from which an electrode sheet on which a plurality of electrodes are formed is unwound; a separation membrane reel from which a separation membrane sheet to be laminated together with the electrodes is unwound; a nozzle that applies an adhesive to at least one of the electrode sheet, the electrode, the separation membrane sheet, and the separation membrane, By changing the type of adhesive injected through the nozzle, a first adhesive portion is formed between the electrode and the separator, and a second adhesive portion is formed between adjacent separators among a plurality of separators included in the electrode assembly; At least a part of a first adhesive forming the first adhesive portion is soluble in an electrolytic solution, and a second adhesive forming the second adhesive portion is insoluble in the electrolytic solution. Secondary battery manufacturing equipment.

29. 29 . The secondary battery manufacturing apparatus of claim 28 , wherein the nozzle has a plurality of nozzles, and the first adhesive and the second adhesive that form the first adhesive portion and the second adhesive portion are applied through different nozzles, respectively.

30. The apparatus for manufacturing a secondary battery according to claim 28 , wherein the separator reel includes a lower separator reel that unwinds a lower separator sheet and an upper separator reel that unwinds an upper separator sheet.

31. a first nozzle that applies one of the first adhesive and the second adhesive to at least a portion of one upward surface of the lower separation membrane sheet unwound from the lower separation membrane reel; a second nozzle that applies one of the first adhesive and the second adhesive to at least a portion of the upper separation membrane sheet that contacts an electrode fixed to one surface of the lower separation membrane sheet to which the adhesive is applied; and a third nozzle configured to apply one of the first adhesive and the second adhesive to at least a portion of the other upward surface of the upper separator sheet.

32. The apparatus of claim 31 , wherein the first nozzle, the second nozzle, and the third nozzle apply the first adhesive or the second adhesive in a plurality of dots.

33. 32. The apparatus for manufacturing a secondary battery of claim 31, further comprising pressure nip rolls disposed on upper and lower surfaces of a stack including the lower separator sheet, the electrode fixed to one surface of the lower separator sheet, the upper separator sheet, and the electrode fixed to the other surface of the upper separator sheet, and configured to apply pressure to the stack.

34. The secondary battery manufacturing apparatus according to claim 33, further comprising a cutter that cuts the laminate at predetermined intervals.

35. The apparatus for manufacturing a secondary battery according to claim 30, further comprising a cutter for cutting the electrode sheet to a predetermined size so that the electrode sheet is placed on one side of the lower separator sheet.

36. 30. The apparatus of claim 28, further comprising a table on which the separator is fixed, wherein the first adhesive or the second adhesive is applied to the separator in a state where the separator is fixed on the table.

37. a header for adsorbing the electrode; The apparatus of claim 36, further comprising: a transfer device that transfers the electrodes so that the header adsorbs the electrodes.

38. The secondary battery manufacturing apparatus according to claim 28 , wherein the nozzle for forming the second adhesive applies the second adhesive in a wobble pattern.

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