Method for manufacturing secondary battery and pre-degassing device for manufacturing secondary battery

Abstract

The present invention relates to a method for manufacturing a secondary battery and a pre-degassing device for manufacturing a secondary battery. The method for manufacturing a secondary battery includes: a housing process, wherein an electrode assembly is housed in a housing formed inside a battery housing to form a battery cell; an electrolyte injection process, wherein an electrolyte is injected into the housing of the battery housing; an initial aging process, wherein a predetermined time passes so that the electrode assembly is impregnated with the electrolyte; an initial charging and discharging process, wherein the battery cell is initially charged and discharged; a pre-degassing process, wherein the battery housing is pressed to discharge the gas inside the electrode assembly to the outside of the electrode assembly; and a secondary aging process, wherein a predetermined time passes so that the electrode assembly is impregnated with the electrolyte, wherein in the pre-degassing process, the battery housing is pressed while applying heat to the battery housing.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2019-0166056, filed on Dec. 12, 2019, which is hereby incorporated by reference in its entirety. Technical Field

[0003] The invention relates to a method for manufacturing a secondary battery and a pre-degassing device for manufacturing a secondary battery. Background Art

[0004] Unlike primary batteries, secondary batteries are rechargeable and have a higher possibility of compact size and high capacity. Therefore, many studies are being conducted on secondary batteries recently. With the development of technology and the increase in demand for mobile devices, the demand for secondary batteries as energy sources is rapidly increasing.

[0005] According to the shape of the battery case, rechargeable batteries are divided into coin-type batteries, cylindrical batteries, prismatic batteries and pouch-type batteries. The secondary battery contains an electrode assembly and an electrolyte. In such a secondary battery, the electrode assembly installed in the battery case is a chargeable and dischargeable power generating device having a structure in which electrodes and separators are stacked.

[0006] Electrode assemblies can be roughly divided into jelly-roll type electrode assemblies, stacked type electrode assemblies, and stacked / folded type electrode assemblies. In the jelly-roll type electrode assembly, a separator is interposed between the positive electrode and the negative electrode, each of the positive electrode and the negative electrode is provided in the form of a sheet coated with an active material, and then the positive electrode, the separator and the negative electrode are wound. In the stacked type electrode assembly, a plurality of positive electrodes and negative electrodes are sequentially stacked with a separator between them, and in the stacked / folded type electrode assembly, stacked unit cells are wound together with an isolation film having a longer length.

[0007] In order to increase battery capacity and improve cycle, secondary batteries are being designed in the direction of increasing the loading amount and the amount of electrolyte additives.

[0008] Increasing the loading amount and the amount of additives in order to improve cycle characteristics results in an increase in the amount of gas (Gas) generated during initial charge.

[0009] Due to the increase in the amount of gas, the gas cannot be effectively removed in the subsequent degassing process. In addition, when increasing the vacuum degree, time, pusher pressure, etc. to remove the gas, there is a problem that the amount of electrolyte discharged from the battery cell increases, which is likely to cause cycle degradation.

[0010] [Prior art document] (Patent document) Korean Patent Publication No. 10-2014-0015647 Summary of the invention

[0011] Technical issues

[0012] An aspect of the present invention is to provide a method of manufacturing a secondary battery capable of removing internal gas of an electrode assembly by additionally performing a pre-degassing process when manufacturing the secondary battery and a pre-degassing apparatus for manufacturing the secondary battery.

[0013] Technical Solution

[0014] According to an embodiment of the present invention, a method for manufacturing a secondary battery includes: a housing process, in which an electrode assembly is housed in a housing portion formed inside a battery case to form a battery cell; an electrolyte injection process, in which an electrolyte is injected into the housing portion of the battery case; an initial aging process, in which a predetermined time passes so that the electrode assembly is impregnated with the electrolyte; an initial charging and discharging process, in which the battery cell is initially charged and discharged; a pre-degassing process, in which the battery case is pressed to discharge gas inside the electrode assembly to the outside of the electrode assembly; and a secondary aging process, in which a predetermined time passes so that the electrode assembly is impregnated with the electrolyte, wherein, in the pre-degassing process, the battery case is pressed while heat is applied to the battery case.

[0015] A pre-degassing device for manufacturing a secondary battery according to an embodiment of the present invention includes: a pressing roller configured to press a battery cell in which an electrode assembly and an electrolyte are accommodated in a battery case while applying heat to the battery cell when manufacturing the secondary battery, after a primary aging process and a primary charging and discharging process and before a secondary aging process; and a supporting body configured to support the pressing roller, wherein the battery case of the battery cell is pressed by the pressing roller to discharge gas inside the electrode assembly to the outside of the electrode assembly.

[0016] Beneficial Effects

[0017] According to the present invention, when manufacturing a secondary battery, a pre-degas process may be additionally performed after initial charging to remove internal gas of the electrode assembly. Therefore, the amount of electrolyte discharged from the inside of the electrode assembly does not increase, thereby preventing cycle degradation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a flowchart illustrating a method of manufacturing a secondary battery according to an embodiment of the present invention.

[0019] Figure 2is a plan view illustrating a housing process in a method of manufacturing a secondary battery according to an embodiment of the present invention.

[0020] Figure 3 is a front view illustrating an electrolyte injection process in a method of manufacturing a secondary battery according to an embodiment of the present invention.

[0021] Figure 4 is a plan view illustrating a primary sealing process in a method of manufacturing a secondary battery according to an embodiment of the present invention.

[0022] Figure 5 is a front view illustrating a preliminary degassing process in a method of manufacturing a secondary battery according to an embodiment of the present invention.

[0023] Figure 6 is a front perspective view illustrating a portion of a pre-degassing device that performs a pre-degassing process in a method of manufacturing a secondary battery according to an embodiment of the present invention.

[0024] Figure 7 is a side view illustrating a pre-degassing device performing a pre-degassing process in a method of manufacturing a secondary battery according to an embodiment of the present invention.

[0025] Figure 8 are front cross-sectional views and side cross-sectional views of a press roller illustrating a pre-degassing process applied in a method of manufacturing a secondary battery according to an embodiment of the present invention.

[0026] Fig. 9 is a front view illustrating a degassing process in a method of manufacturing a secondary battery according to an embodiment of the present invention.

[0027] Fig.10 is a front view illustrating a secondary sealing process in a method of manufacturing a secondary battery according to an embodiment of the present invention.

[0028] Fig.11 is a graph illustrating the amount of electrolyte discharged during a degassing process in a method of manufacturing a secondary battery according to the related art and an embodiment of the present invention.

[0029] Fig.12 is a graph illustrating secondary formation capacity when a secondary battery is manufactured according to the related art and according to an embodiment of the present invention.

[0030] Fig.13 is a photograph illustrating an unreacted area on the surface of a negative electrode due to a reaction gas when fully deintercalated after primary charge in a method of manufacturing a secondary battery according to the related art and an embodiment of the present invention.

[0031] Fig.14is a photograph illustrating Li-plating on the surface of a negative electrode due to a reaction gas when fully deintercalated after primary charge in a method of manufacturing a secondary battery according to the related art and an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The purpose, specific advantages and novel features of the present invention will become more apparent through the following detailed description in conjunction with the accompanying drawings. It should be noted that reference numerals are added to the components in the drawings of the present application with the same reference numerals as much as possible, even if these components are shown in other drawings. In addition, the present invention can be implemented in different forms and should not be construed as being limited to the embodiments set forth herein. In the following description of the present invention, detailed descriptions of related technologies that may unnecessarily obscure the subject matter of the present invention will be omitted.

[0033] Method for manufacturing secondary battery

[0034] Figure 1 is a flowchart illustrating a method of manufacturing a secondary battery according to an embodiment of the present invention, Figure 2 is a plan view illustrating a housing process in a method of manufacturing a secondary battery according to an embodiment of the present invention, Figure 3 is a front view illustrating an electrolyte injection process in a method of manufacturing a secondary battery according to an embodiment of the present invention.

[0035] Figure 4 is a plan view illustrating a primary sealing process in a method for manufacturing a secondary battery according to an embodiment of the present invention, Figure 5 is a front view illustrating a preliminary degassing process in a method of manufacturing a secondary battery according to an embodiment of the present invention.

[0036] Reference Figures 1 to 5 According to an embodiment of the present invention, the method for manufacturing a secondary battery includes: an accommodating process (S10) of accommodating an electrode assembly 110 in a battery case 120; an electrolyte injection process (S20) of injecting an electrolyte; a primary aging process for a predetermined time; a primary charging and discharging process (S50) of performing initial charging and discharging; a pre-degassing process (S60) of pressing the battery case 120; and a secondary aging process (S70) for a predetermined time, thereby manufacturing a secondary battery.

[0037] In addition, the method of manufacturing a secondary battery according to an embodiment of the present invention further includes a primary sealing process ( S30 ) of sealing the battery case 120 after the electrolyte injection process ( S20 ).

[0038] Reference Figure 2, the battery cell 100 includes a battery case 120 and an electrode assembly 110 accommodated in a receiving portion 121 of the battery case 120. Here, the electrode assembly 110 may include electrode leads 111 and 112 electrically connected to electrodes.

[0039] The electrode assembly 110 may be a chargeable and dischargeable power generating element, and may be formed by alternately stacking electrodes and separators.

[0040] The electrode may be composed of a positive electrode and a negative electrode. At this time, the electrode assembly 110 may have a structure in which positive electrode / separator / negative electrode are alternately stacked. In addition, the electrode leads 111 and 112 may include a positive electrode lead 111 connected to the positive electrode and a negative electrode lead 112 connected to the negative electrode.

[0041] The positive electrode may include a positive electrode collector and a positive electrode active material stacked on the positive electrode collector.

[0042] The positive electrode current collector may be made of aluminum foil.

[0043] The positive electrode active material may include lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron phosphate, or a compound or mixture including at least one of the foregoing materials.

[0044] The negative electrode may include a negative electrode collector and a negative electrode active material stacked on the negative electrode collector.

[0045] The negative electrode current collector may be made of, for example, a foil made of a copper (Cu) material.

[0046] The negative electrode active material may be a compound or a mixture including a graphite-based material.

[0047] The separator is made of an insulating material to electrically insulate the positive electrode and the negative electrode from each other. Here, the separator may be made of a polyolefin resin film such as polyethylene or polypropylene having microporosity.

[0048] Reference Figure 1 and Figure 2 In the housing process ( S10 ), the electrode assembly 110 may be housed in a housing portion 121 formed inside a battery case 120 to form a battery cell 100 .

[0049] Here, refer to Figure 2 and Figure 3 The battery case 120 may include: a receiving portion 121 receiving the electrode assembly 110 ; and a gas pocket portion 122 connected to the receiving portion 121 to collect gas generated in the receiving portion 121 .

[0050] Reference Figure 1 and Figure 3In the electrolyte injection process ( S20 ), the electrolyte may be injected into the accommodation portion 121 of the battery case 120 .

[0051] At this time, in the electrolyte injection process ( S20 ), the electrolyte may be injected into the battery case 120 through the electrolyte supply pipe P.

[0052] Here, the electrolyte may include salt, a solvent, and an additive.

[0053] Reference Figure 1 and Figure 4 In the primary sealing process ( S30 ), the battery case 120 may be sealed after the electrolyte injection process ( S20 ).

[0054] Here, in the primary sealing process ( S30 ), after the electrolyte injection process ( S20 ) and before the primary aging process ( S40 ), the open portion of the battery case 120 may be sealed to form a sealing portion S1 .

[0055] At this time, the open portion may be sealed by heat-sealing the end of the air pocket portion 122 in the battery case 120 .

[0056] In the primary aging process ( S40 ), a predetermined time may elapse so that the electrode assembly is impregnated with the electrolyte.

[0057] Thus, the electrode assembly may be impregnated with the electrolyte, allowing lithium ions to move smoothly.

[0058] In the initial charging and discharging process ( S50 ), the battery cell 100 may be initially charged and discharged.

[0059] In the primary charging and discharging process ( S50 ), the battery cell 100 may be charged by connecting power to the electrode leads 111 and 112 of the battery cell 100 .

[0060] Figure 6 is a front perspective view illustrating a portion of a pre-degassing device for performing a pre-degassing process in a method for manufacturing a secondary battery according to an embodiment of the present invention, Figure 7 is a side view illustrating a pre-degassing device for performing a pre-degassing process in a method for manufacturing a secondary battery according to an embodiment of the present invention, Figure 8 are front cross-sectional views and side cross-sectional views of a press roller illustrating a pre-degassing process applied in a method of manufacturing a secondary battery according to an embodiment of the present invention.

[0061] Reference Figure 1 and Figures 6 to 8, in the pre-degassing process (S60), the battery case 120 of the battery cell 100 may be pressed to discharge the gas (Gas) inside the electrode assembly 110 to the outside of the electrode assembly 110. Here, in the pre-degassing process (S60), the gas inside the electrode assembly 110 in the battery case 120 may be discharged to the outside of the electrode assembly 110 without forming a hole in the battery case 120. Then, the gas discharged to the outside of the electrode assembly 110 may be discharged to the outside of the battery case 120. Thus, the internal gas of the electrode assembly 110 may be removed by pre-degassing, thereby reducing the unreacted area on the negative electrode because the amount of the electrolyte discharged from the inside of the electrode assembly 110 is not increased, and also preventing cycle degradation.

[0062] In addition, a pre-degassing process ( S60 ) may be sequentially performed on the battery cells 100 conveyed by the conveyor belt C as a conveying member through the pre-degassing device 200 .

[0063] In addition, in the pre-degassing process (S60), the battery case 120 of the battery cell 100 may be pressed while applying heat to the battery case 120 of the battery cell 100. Thus, due to the increase in the temperature of the battery cell 100, the removal ability of the internal gas of the electrode assembly 110 contained in the battery cell 100 can be improved, and because heat and pressure are applied at the same time, the appearance of the battery cell 100 can be prevented from wrinkling, thereby improving the stiffness. Here, in the pre-degassing process (S60), the battery case 120 of the battery cell 100 may be pressed while applying heat having a temperature of 20°C to 100°C. Here, in the pre-degassing process (S60), heat may be applied to the battery case 120 by the pressing roller 230 set as an induction heating roller.

[0064] In addition, the pressing roller 230 may include an upper roller 210 and a lower roller 220 to press the upper and lower portions of the battery cell 100. Here, the upper roller 210 or each of the upper roller 210 and the lower roller 220 may be provided as an induction heating roller.

[0065] At this time, refer to Figure 8 The upper roller 210 may include a shaft 212 disposed at the center, an induction coil 213 wound on the outer circumferential surface of the shaft 212, and an outer cylinder 211 disposed on the outer circumferential surface. When the induction coil 213 is powered, a magnetic flux 214 passing through the outer cylinder 211 of the upper roller 210 is generated. As a result, the magnetic flux 214 may generate an eddy current in the outer cylinder 211, such as Figure 8As shown in (a) of FIG. 1 , a current flow like an equivalent circuit may be generated, thereby heating the outer cylinder 211. At this time, the heat generated by the initial heat generating portion 215 of the outer cylinder 211 may start to heat the entire outer cylinder 211.

[0066] In addition, refer to Figure 1 and Figures 5 to 7 In the pre-degassing process (S60), the outer surface of the battery case 120 may be pressed by the pressing roller 230 in a rolling (RollPress) manner. Here, in the pre-degassing process (S60), the outer surface of the battery case 120 may be rolled (Rolling) by the pressing roller to press the battery cell 100.

[0067] In addition, in the pre-degassing process (S60), the pressing force applied to the battery case 120 may be adjusted according to the structure and thickness of the battery cell 100. Here, the pressing force may be adjusted within a pressure range of 100 kgf to 400 kgf. At this time, in the pre-degassing process (S60), the actuator 270 may be connected to the support body 240 supporting the pressing roller 230 to adjust the pressing force applied to the battery case 120 of the battery cell 100 by the actuator 270. Here, the support body 240 rotatably supports the upper roller 210, and the pressing force applied to the battery cell 100 may be adjusted by adjusting the pressing force applied to the upper roller 210 by the actuator 270.

[0068] In addition, in the pre-degassing process (S60), the distance between the upper roller 210 and the lower roller 220 may be adjusted according to the thickness of the battery cell 100. Here, in the pre-degassing process (S60), the distance between the upper roller 210 and the lower roller 220 may be adjusted by the distance adjusting member 280.

[0069] The distance adjusting member 280 may include a motor 281 and a screw 282 rotated by the motor 281 .

[0070] When the screw 282 is rotated by the motor 281, the moving frame 260 coupled to the screw moves up and down. At this time, the support body 240 supporting the upper roller 210 disposed below the moving frame 260 can move up and down to adjust the distance between the upper roller 210 and the lower roller 220.

[0071] The motor 281 may be configured as a servo motor.

[0072] The lower roller 220 may be rotatably supported by the support portion 250 .

[0073] In the secondary aging process ( S70 ), a predetermined time may elapse so that the electrode assembly 110 is impregnated with the electrolyte.

[0074] In the secondary aging process ( S70 ), the battery cell 100 may be subjected to a predetermined time at room temperature and a high temperature.

[0075] Fig. 9 is a front view illustrating a degassing process in a method of manufacturing a secondary battery according to an embodiment of the present invention, Fig.10 is a front view illustrating a secondary sealing process in a method of manufacturing a secondary battery according to an embodiment of the present invention.

[0076] Reference Figure 1 , Fig. 9 and Fig.10 , the method of manufacturing a secondary battery according to an embodiment of the present invention further includes a degassing process ( S80 ), a secondary sealing process ( S90 ), and a secondary charging and discharging process ( S100 ) after the secondary aging process ( S70 ).

[0077] Reference Figure 1 and Fig. 9 After performing the secondary aging process ( S70 ), in a degassing process, internal gas of the battery case 120 may be discharged to the outside of the battery case 120 before the secondary charging and discharging process ( S100 ).

[0078] At this time, the sealing portion S1 formed at the end of the air pocket portion 122 in the battery case 120 may be removed by cutting using a cutter to discharge internal gas of the battery case 120 through the cut portion of the air pocket portion 122 .

[0079] Reference Figure 1 and Fig.10 In the secondary sealing process ( S90 ), the battery case 120 may be sealed after performing the degassing process ( S80 ).

[0080] In addition, in the secondary sealing process ( S90 ), the air pocket portion may be cut and removed, and then the removed portion may be formed into a sealed portion S2 by heat fusion to seal the battery case 120 .

[0081] In the secondary charging and discharging process (S100), after the secondary aging process (S70) is performed, the battery cell 100 may be charged and discharged to manufacture a secondary battery. Here, in the secondary charging and discharging process (S100), after the secondary aging process (S70) and the secondary sealing process (S90) are performed, the battery cell 100 may be charged and discharged to manufacture a secondary battery. Figure 1 ).

[0082] In addition, in a secondary charging and discharging process, the battery cell 100 may be charged by connecting power to the electrode leads 111 and 112 of the battery cell 100 .

[0083] Fig.11 is a graph illustrating the amount of electrolyte discharged during a degassing process in a method of manufacturing a secondary battery according to the related art and an embodiment of the present invention.

[0084] like Fig.11 As shown in the graph of , when the battery cell A manufactured in the process of manufacturing a secondary battery according to the related art was degassed, the amount of electrolyte discharged from the inside of the electrode assembly was 0.416 g. On the other hand, when the battery cell B manufactured in the process of manufacturing a secondary battery according to an embodiment of the present invention was degassed, the amount of electrolyte discharged from the inside of the electrode assembly was 0.05 g.

[0085] In more detail, in the battery cell A manufactured in the process of manufacturing a secondary battery according to the related art, when a degassing process is performed in which a hole is formed in the battery case to discharge the gas inside the battery case to the outside, the gas inside the battery case is discharged together with the electrolyte during the discharge of the gas to the outside of the battery case through the outside of the electrode assembly. At this time, the gas inside the electrode assembly pushes the electrolyte, thereby increasing the amount of the discharged electrolyte.

[0086] However, when the battery cell B manufactured in the process of manufacturing a secondary battery according to an embodiment of the present invention is degassed, the gas inside the electrode assembly is discharged to the outside of the electrode assembly through a pre-degassing process. Then, the discharged gas is disposed above the electrolyte, so that only the gas disposed above the electrolyte is discharged, and a hole is formed in the battery case to discharge only the gas disposed above the electrolyte. Thus, the amount of discharged electrolyte is significantly reduced.

[0087] As a result, in the battery cell B manufactured in the process of manufacturing a secondary battery according to an embodiment of the present invention in which a pre-degassing process is performed, the amount of electrolyte discharged from the inside of the electrode assembly is quite low, and thus cycle degradation can be expected not to occur.

[0088] Fig.12 is a graph illustrating secondary formation capacity when a secondary battery is manufactured according to the related art and according to an embodiment of the present invention.

[0089] like Fig.12 As shown in the graph, the average capacity of the secondary formation (Formation) of the battery cell A manufactured in the process of manufacturing a secondary battery according to the related art is 62.1199 (Ah). On the other hand, it can be seen that the average capacity of the secondary formation (Formation) of the battery cell B manufactured in the process of manufacturing a secondary battery according to an embodiment of the present invention is 62.6369 (Ah).

[0090] Therefore, compared with battery cell A manufactured in the process of manufacturing a secondary battery according to the related art, in battery cell B manufactured in the process of manufacturing a secondary battery according to an embodiment of the present invention in which a pre-degassing process is performed, it can be seen that the secondary formation capacity is improved due to the reduction of the unreacted area on the negative electrode.

[0091] Fig.13 is a photograph illustrating an unreacted area on the surface of a negative electrode due to a reaction gas when fully deintercalated after primary charge in a method of manufacturing a secondary battery according to the related art and an embodiment of the present invention.

[0092] like Fig.13 As shown in (a), when a battery cell is completely released after initial charge in a process of manufacturing a secondary battery according to the related art, it can be seen that an unreacted area on the surface of the negative electrode due to the reaction gas occupies a wide area.

[0093] However, if Fig.13 As shown in (b), when the battery cell is completely deintercalated after the initial charge in the process of manufacturing the secondary battery according to the embodiment of the present invention, it can be seen that the unreacted area on the surface of the negative electrode due to the reaction gas is significantly reduced.

[0094] Therefore, it can be seen that, compared with the battery cell manufactured in the method for manufacturing a secondary battery according to the related art, in the battery cell manufactured in the method for manufacturing a secondary battery according to an embodiment of the present invention in which a pre-degassing process is performed, the battery capacity is significantly improved due to the reduction of the unreacted area on the negative electrode.

[0095] Fig.14 is a photograph illustrating Li-plating on the surface of a negative electrode due to a reaction gas when fully deintercalated after primary charge in a method of manufacturing a secondary battery according to the related art and an embodiment of the present invention.

[0096] like Fig.14 As shown in (a), when a battery cell is completely deintercalated after primary charge in a process of manufacturing a secondary battery according to the related art, it can be seen that Li-plating due to reaction gas occupies a wider area.

[0097] However, if Fig.14 As shown in (b), when the battery cell is completely deintercalated after the initial charge of the battery cell in the process of manufacturing a secondary battery according to an embodiment of the present invention, it can be seen that the Li-plating portion caused by the reaction gas on the negative electrode of the electrode assembly is significantly reduced.

[0098] Therefore, it can be seen that, compared with the battery cell manufactured in the method for manufacturing a secondary battery according to the related art, in the battery cell manufactured in the method for manufacturing a secondary battery according to an embodiment of the present invention in which a pre-degassing process is performed, the battery capacity is improved due to a significant reduction in the Li-plating portion in which lithium ions are solidified.

[0099] Pre-degassing device for manufacturing secondary batteries

[0100] Hereinafter, an apparatus for manufacturing a secondary battery according to an embodiment of the present invention will be described.

[0101] Reference Figure 2 , Figures 5 to 8 , the apparatus for manufacturing a secondary battery according to an embodiment of the present invention includes: a press roller 230 that presses the battery cell 100 while applying heat to the battery cell 100 in which the electrode assembly 110 and the electrolyte are accommodated in the battery case 120; and a support body 240 that supports the press roller 230. In addition, the apparatus for manufacturing a secondary battery according to an embodiment of the present invention may further include a distance adjustment member 280 and an actuator 270.

[0102] The pre-degassing device 200 for manufacturing a secondary battery according to an embodiment of the present invention is a pre-degassing device 200 for manufacturing a secondary battery applied to the method for manufacturing a secondary battery according to an embodiment of the present invention. Therefore, in the description of the pre-degassing device 200 for manufacturing a secondary battery according to this embodiment of the present invention, the contents repeated with the method for manufacturing a secondary battery according to the foregoing embodiment of the present invention will be omitted or briefly described, and the differences therebetween will be mainly described.

[0103] In more detail, in the pre-degassing device 200 for manufacturing a secondary battery according to an embodiment of the present invention, when manufacturing a secondary battery, after the primary aging process (S40) and the primary charging and discharging process (S50) and before the secondary aging process (S70), the battery case 120 of the battery cell 100 is pressed by the pressing roller 230 to discharge the gas inside the electrode assembly 110 to the outside of the electrode assembly 110 (see FIG. 2 ). Figure 1 ).

[0104] The pressing roller 230 may press the battery cell 100 while applying heat to the battery cell 100 in which the electrode assembly 110 and the electrolyte are accommodated in the battery case 120. Here, the pressing roller 230 may press the outer surface of the battery case 120 in a rolling (Roll Press) manner. That is, the outer surface of the battery case 120 may be rolled (Rolling) by the pressing roller 230 to press the battery cell 100.

[0105] In addition, the pressing roller 230 may include an upper roller 210 and a lower roller 220 to press the upper and lower portions of the battery cell 100 .

[0106] In addition, the battery case 120 of the battery cell 100 may be pressed while heat having a temperature of 20° C. to 100° C. is applied.

[0107] In addition, the press roller 230 may be provided as an induction heating roller to apply heat to the battery case 120. The upper roller 210 or each of the upper roller 210 and the lower roller 220 may be provided as an induction heating roller.

[0108] At this time, refer to Figure 8 The upper roller 210 may include a shaft 212 disposed at the center, an induction coil 213 wound on the outer circumferential surface of the shaft 212, and an outer cylinder 211 disposed on the outer circumferential surface. When power is supplied to the induction coil 213, a magnetic flux is generated that passes through the outer cylinder 211 of the upper roller 210. As a result, the magnetic flux may generate an eddy current in the outer cylinder 211, such as Figure 8 As shown in (a) of FIG. 1 , a current flow like an equivalent circuit may be generated, thereby heating the outer cylinder 211. At this time, the heat generated by the initial heat generating portion 215 of the outer cylinder 211 may start to heat the entire outer cylinder 211.

[0109] Reference Figures 5 to 7 , the support body 240 may support the pressing roller 230. At this time, the support body 240 may support the upper roller 210. Here, the upper roller 210 may be rotatably installed on the support body 240.

[0110] The distance adjusting member 280 may adjust the distance between the upper roller 210 and the lower roller 220 by moving the support body 240. At this time, the distance adjusting member 280 may move the support body 240 up and down by moving the frame 260 to move the upper roller 210 in the up and down directions.

[0111] The distance adjusting member 280 may include a motor 281 and a screw 282 rotated by the motor 281 .

[0112] When the screw 282 is rotated by the motor 281, the moving frame 260 coupled to the screw moves up and down. At this time, the support body 240 supporting the upper roller 210 disposed below the moving frame 260 may move up and down to adjust the distance between the upper roller 210 and the lower roller 220. Here, a threaded portion may be formed on the outer circumferential surface of the screw 282, and a spiral groove corresponding to the threaded portion of the screw 282 may be formed in the moving frame 260.

[0113] The motor 281 may be configured as a servo motor.

[0114] The lower roller 220 may be rotatably supported by the support portion 250 .

[0115] The actuator 270 (actuator) may be connected to the support body 240 on which the upper roller 210 is mounted. Here, the actuator may adjust the pressing force applied to the battery case 120. At this time, the actuator 270 may adjust the pressing force applied to the battery cell 100 by adjusting the pressing force applied to the upper roller 210 via the support body 240.

[0116] In addition, the actuator 270 adjusts the pressing force applied to the battery case 120 according to the structure and thickness of the battery cell 100. Here, the pressing force may be adjusted within a pressure range of 100 kgf to 400 kgf.

[0117] Furthermore, the actuator 270 may be configured as a pneumatic actuator or a hydraulic actuator.

[0118] Reference Figure 1 , Figure 2 and Figure 5 As described above, in the pre-degassing device 200 for manufacturing a secondary battery according to an embodiment of the present invention, when manufacturing a secondary battery, after the primary aging process (S40) and the primary charging and discharging process (S50) and before the secondary aging process (S70), the battery cell 100 in which the electrode assembly 110 and the electrolyte are accommodated in the battery case 120 may be pressed while applying heat, thereby discharging gas inside the electrode assembly 110 to the outside of the electrode assembly 110.

[0119] Therefore, the unreacted area on the surface of the negative electrode can be significantly reduced without increasing the amount of electrolyte discharged from the inside of the electrode assembly 110, and Li-plating on the surface of the negative electrode can be significantly reduced.

[0120] As a result, the battery capacity can be increased, and cycle degradation can be prevented.

[0121] Although the present invention has been specifically shown and described with reference to specific embodiments of the present invention, the method for manufacturing a secondary battery and the pre-degassing device for manufacturing a secondary battery according to the present invention are not limited thereto. It will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention.

[0122] Furthermore, the protective scope of the present invention will be set forth by the accompanying claims.

[0123] [Description of symbols]

[0124] 100: Battery Cell

[0125] 110: Electrode assembly

[0126] 111: Positive lead

[0127] 112: Negative lead

[0128] 120: Battery housing

[0129] 121: Accommodation

[0130] 122: Airbag Department

[0131] 200: Pre-degassing device

[0132] 210: Upper roller

[0133] 220: Lower roller

[0134] 230: Pressure roller

[0135] 240: Support body

[0136] 250: Support

[0137] 260: Mobile Frame

[0138] 270: Actuator

[0139] 280: Distance adjustment component

[0140] 281: Motor

[0141] 282: Screw

[0142] P: Electrolyte supply pipe

[0143] S1: Sealing part

[0144] S2: Sealed part.

Claims

1. A method for manufacturing a secondary battery, the method comprising: an accommodation step of accommodating the electrode assembly in an accommodation portion formed inside the battery case to form a battery cell; an electrolyte injection step of injecting an electrolyte into the receiving portion of the battery case; A primary aging process, after a predetermined time, so that the electrode assembly is impregnated with the electrolyte; An initial charging and discharging process, charging and discharging the battery cell for the initial time; a pre-degassing process of pressing the battery case to discharge gas inside the electrode assembly to the outside of the electrode assembly so that the discharged gas is disposed above the electrolyte; and A secondary aging process, after a predetermined time, so that the electrode assembly is impregnated with the electrolyte, wherein, in the pre-degassing step, the battery housing is pressed while applying heat to the battery housing; In the pre-degassing process, the outer surface of the battery housing is pressed by a roller in a rolling manner. wherein, in the pre-degassing process, the pressing force applied to the battery housing is adjusted according to the structure and thickness of the battery cell, and Wherein, in the pre-degassing process, an actuator provided in the moving frame is connected to a supporting body provided below the moving frame and supporting the pressing roller, so that the pressing force applied to the battery housing is adjusted by the actuator, wherein the pressing roller comprises an upper roller and a lower roller for pressing the upper and lower parts of the battery cell respectively, and In the pre-degassing process, the distance between the upper roller and the lower roller is adjusted by a distance adjusting component according to the thickness of the battery cell. wherein the support body supports the upper roller, The distance adjusting component is configured to move the moving frame up and down to move the supporting body up and down, thereby adjusting the distance between the upper roller and the lower roller, and The distance adjustment component includes a motor and a screw rotated by the motor, and the actuator is configured as a pneumatic actuator or a hydraulic actuator. 2 . The method according to claim 1 , further comprising a secondary charging and discharging process of secondarily charging and discharging the battery cell after the secondary aging process. 3 . The method according to claim 2 , further comprising a degassing process of discharging internal gas of the battery case to the outside of the battery case after the secondary aging process and before the secondary charging and discharging process.

4. The method according to claim 3, wherein: In the secondary aging process, the battery cell is subjected to the predetermined time at room temperature and high temperature.

5. The method according to claim 1, wherein: In the preliminary degassing process, the battery case is pressed while applying heat having a temperature of 20° C. to 100° C. The method according to claim 1 , wherein the pressing force is adjusted within a pressure range of 100 kgf to 400 kgf.

7. The method according to claim 1, wherein: In the pre-degassing process, heat is applied to the battery case by a pressure roller configured as an induction heating roller.

8. A pre-degassing device for manufacturing a secondary battery, the pre-degassing device comprising: a pressing roller configured to press a battery cell in which an electrode assembly and an electrolyte are accommodated in a battery case while applying heat to the battery cell after a primary aging process and a primary charging and discharging process and before a secondary aging process when manufacturing a secondary battery; Mobile framework; a support body disposed below the moving frame and configured to support the pressing roller; an actuator disposed in the mobile frame and connected to the support body; and Distance adjustment components, wherein the battery case of the battery cell is pressed by the pressing roller to discharge the gas inside the electrode assembly to the outside of the electrode assembly so that the discharged gas is disposed above the electrolyte, and wherein the actuator adjusts the pressing force applied to the battery housing according to the structure and thickness of the battery cell, The pressing roller comprises an upper roller and a lower roller for pressing the upper and lower parts of the battery cell respectively. wherein the support body supports the upper roller, The distance adjusting component is configured to move the moving frame up and down to move the supporting body up and down, thereby adjusting the distance between the upper roller and the lower roller, and The distance adjustment component includes a motor and a screw rotated by the motor, and the actuator is configured as a pneumatic actuator or a hydraulic actuator. 9 . The pre-degassing device according to claim 8 , wherein the pressing roller is configured as an induction heating roller to apply heat to the battery casing.

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