Method for manufacturing secondary battery

Abstract

The present invention relates to an apparatus and a method for manufacturing a secondary battery and, more specifically, to a method and an apparatus for manufacturing a secondary battery by easily checking the degree of impregnation by an electrolyte. To this end, according to one embodiment of the present invention, a method for manufacturing a pouch-type secondary battery may be provided, the method comprising: a pre-aging step for inserting an electrode assembly into a pouch case and assembling same, and injecting an electrolyte into the pouch case and sealing the pouch case; and an impregnation checking step for, after the pre-aging step, pressing the outer surface of the pouch case through a pad sensor having a plurality of nodes, and checking the degree of impregnation of the electrode assembly by the electrolyte on the basis of the deviation of pressures sensed through the plurality of nodes.

Description

Secondary battery manufacturing method

[0001] The present invention relates to a secondary battery manufacturing device and method, and more specifically, to a manufacturing method and device for manufacturing a secondary battery in which the degree of impregnation with an electrolyte can be easily confirmed during the secondary battery manufacturing process.

[0002] This application claims the benefit of priority to Republic of Korea Patent Application No. 10-2024-0120195, filed September 4, 2024, the entire contents of which are incorporated herein by reference.

[0003] With the proliferation of portable, small-sized electronic devices, the development of new types of secondary batteries, such as nickel-metal hydride batteries and lithium secondary batteries, is rapidly progressing. Recently, lithium secondary batteries are being widely used not only in power tools but also in automobiles.

[0004] A lithium secondary battery is a battery that uses carbon such as graphite as an anode active material, an oxide containing lithium as an anode material, and a non-aqueous solvent as an electrolyte.

[0005] These secondary batteries are manufactured in the form of a battery assembly, where the electrode assembly, in which the positive electrode, separator, and negative electrode are sequentially measured, is housed in an outer packaging material, such as a pouch or cylindrical can, i.e., a battery case. Next, an electrolyte injection device is used to inject the electrolyte into the battery assembly. This process is generally referred to as the packaging process. During the packaging process, the separator must be sufficiently impregnated after the electrolyte is injected to ensure sufficient electrolyte filling between the electrodes.

[0006] Figure 1 illustrates an example of a pouch-type secondary battery.

[0007] A pouch-type secondary battery (10) is formed by sealing an electrode assembly (20) together with an electrolyte inside a pouch case (30). The leads (21, 22) of the electrode assembly (20) penetrate the pouch case (30) and are exposed to the outside. This process can be referred to as a pre-aging process.

[0008] A pouch-type secondary battery (10) is generally formed into a rectangular shape having long sides and short sides, and a lead (21, 22) is provided on the short side. In this case, the sealing on the short side is called a top sealing (31), and the sealing on the long side is called a side sealing (32). One of the two long side seals is formed by folding the pouch sheet.

[0009] Specifically, the pre-aging process forms a gas pocket inside the pouch case by performing primary side sealing, and the pre-aging process (S10) can be completed through primary side sealing.

[0010] Thereafter, a pre-formation process for initially activating the pouch-type secondary battery (10) through initial charging and discharging may be performed, and a degassing process (S20) for discharging gas generated inside the pouch case (30) may be performed. After completion of the degassing process (S20), a secondary side sealing process may be performed, and the primary side sealing that formed the gas pocket may be removed.

[0011] After the degassing process, a formation process, an aging process, an OCV process, and a sorting process can be performed.

[0012] The formation process can be defined as a process that imparts electrical energy characteristics to the battery by repeatedly charging and discharging it. The aging process ensures that the electrolyte is sufficiently dispersed across the positive and negative electrode materials, and the OCV process is a process that tests the battery's performance and quality.

[0013] Unlike square or cylindrical cases, pouch cases (30) may be susceptible to swelling. Therefore, degassing is very important for pouch-type secondary batteries, unlike other secondary batteries.

[0014] Meanwhile, pouch-type secondary batteries that are not fully impregnated may generate gas during use, potentially increasing the risk of swelling. Therefore, confirming and improving impregnation performance in pouch-type secondary batteries is crucial.

[0015] Furthermore, incomplete electrolyte impregnation can lead to reduced capacity in secondary batteries. This incomplete electrolyte impregnation exacerbates electrode inhomogeneity, leading to localized electrode reactions and potentially localized lithium precipitation. This lithium precipitation not only degrades secondary battery performance but can also damage the separator.

[0016] With the recent trend toward higher capacity in secondary batteries, the unit size of electrode assemblies is increasing, making electrolyte impregnation increasingly important. This is because the area where impregnation imbalances can occur in medium- to large-sized secondary batteries increases, further increasing the potential for performance variations among secondary batteries due to impregnation imbalances. Therefore, easily assessing the degree of impregnation, i.e., whether impregnation is complete, is crucial.

[0017] However, confirming the complete impregnation of the electrolyte is not easy. While the degree of impregnation can be determined by disassembling battery samples during the manufacturing process, this is time-consuming and expensive, and its effectiveness and accuracy are difficult to guarantee.

[0018] Therefore, an impregnation verification process that guarantees effectiveness and accuracy is required, and a method must be developed to organically integrate this impregnation verification process into the entire manufacturing process.

[0019] The purpose of the present invention is to solve the problems of the conventional pouch-type secondary battery manufacturing method.

[0020] Through one embodiment of the present invention, it is intended to provide a method for manufacturing a pouch-type secondary battery that can easily determine the degree of impregnation of an electrolyte and determine the completion of impregnation.

[0021] Through one embodiment of the present invention, it is intended to provide a method for manufacturing a pouch-type secondary battery that can be easily applied to existing manufacturing devices and manufacturing processes to perform impregnation completion determination.

[0022] Through one embodiment of the present invention, a method for manufacturing a pouch-type secondary battery is provided, which can easily determine whether optimal electrolyte impregnation has been performed in a given process by pressurizing the outer surface of the pouch-type secondary battery and sensing the rebound pressure at each location.

[0023] Through one embodiment of the present invention, it is intended to provide a pouch-type secondary battery manufacturing device capable of easily determining whether impregnation is complete using the pouch-type secondary battery manufacturing device, and a manufacturing method using the same.

[0024] In order to achieve the above-described purpose, according to one embodiment of the present invention, a method for manufacturing a pouch-type secondary battery may be provided, including a pre-aging step of assembling an electrode assembly by inserting it into a pouch case, injecting an electrolyte into the pouch case, and sealing it; and an impregnation confirmation step of pressurizing an outer surface of the pouch case through a pad sensor having a plurality of nodes after the pre-aging step, and confirming the degree of impregnation of the electrolyte into the electrode assembly based on a deviation in pressures sensed through the plurality of nodes.

[0025] After the pre-aging step, a pre-formation step may be performed to improve the impregnation properties of the pouch-type secondary battery by pressurizing it. Generally, pre-formation is a process for qualitatively improving the impregnation properties of a secondary battery by pressurizing it. In the present embodiment, the pre-formation process can be simultaneously performed to not only improve the impregnation properties but also to confirm the degree or completeness of the impregnation properties. Accordingly, a pad sensor may be mounted on the pre-formation jig where the pre-formation process is performed.

[0026] The pad sensor may be interposed between the pouch case and the pressure plate so that the pad sensor presses the outer surface of the pouch case by the pressure plate. Here, the pressure plate may be a part of a pre-formation jig.

[0027] The pressure plate can pressurize the outer surface of the pouch case through the pad sensor with uniform pressure. The entire pad sensor can pressurize the outer surface of the pouch case by the pressure plate.

[0028] The above-described plurality of nodes may be provided in a grid shape on the pad sensor so as to independently sense pressure. Accordingly, each node can sense the pressure on the outer surface of the pouch case at a different location.

[0029] Therefore, when a uniform pressure is applied, multiple nodes can independently sense the pressure on the outer surface of the pouch case. If the pressure sensed at each location is uniform, impregnation can be determined to be complete. If the pressure sensed at each location is uneven, impregnation can be determined to be incomplete, i.e., insufficient.

[0030] The pressure sensed by each of the plurality of nodes may be displayed numerically on the image of the pad sensor. For example, an image of the pad sensor corresponding to the outer surface of the pouch case may be displayed, and a plurality of grid patterns may be displayed on the pad sensor. Each grid may correspond to a respective node.

[0031] The sensed pressure can be displayed within the above grid. The pressure can be expressed numerically. Here, the pressure can refer to displacement due to pressurization. That is, when the node of the pad sensor presses the outer surface of the pouch case, the sensed pressure can be converted to decrease as the thickness change of the pouch case increases.

[0032] Therefore, the numerical value displayed within the above grid may be a sensing pressure or a sensing displacement, or may be a calculated displacement.

[0033] Depending on the size of the above figure, the color may be displayed in different colors. Therefore, if the color is uniform throughout, impregnation can be intuitively determined to be complete. Of course, if the color is uneven throughout, impregnation can be intuitively determined to be incomplete. Higher sensing pressures may be displayed in a dark red, while lower sensing pressures may be displayed in a dark blue.

[0034] The above multiple nodes are divided into multiple analysis areas and non-analyzed areas, and the degree of impregnation can be measured based on the pressure difference between the analysis areas.

[0035] The pouch case is formed in a rectangular shape with a plane having long and short sides, and its thickness is relatively much smaller than the lengths of the long and short sides. Therefore, one of the upper and lower surfaces can be supported, and the other surface can be pressurized through a pad sensor.

[0036] The pad sensor may be provided on a gripper that presses the upper and lower surfaces of the pouch case to secure the pouch case. The gripper may be a device that transports the pouch case between processes.

[0037] The gripper includes an upper gripper that presses the upper surface of the pouch case and a lower gripper that presses the lower surface of the pouch case, and the pad sensor may be provided on either the upper gripper or the lower gripper.

[0038] The gripper may be provided in multiple numbers to form multiple analysis areas by varying the pressing positions on the outer surface of the pouch case.

[0039] The above gripper may be provided in multiple numbers corresponding to the multiple analysis areas.

[0040] The plurality of grippers may be arranged to be parallel to each other and may be arranged to grasp the pouch-shaped secondary battery while crossing it. That is, the plurality of grippers may be arranged to grasp the pouch-shaped secondary battery in parallel with the short side of the pouch case.

[0041] After the above pre-aging step, a degassing step is included for initially charging and discharging gas inside the pouch case to the outside, and the impregnation confirmation step can be performed after the degassing step.

[0042] After the above degassing step, an OCV step is included to perform quality inspection through open circuit voltage (OCV) measurement, and it is preferable that the impregnation confirmation step is performed before the OCV step.

[0043] In order to achieve the above-described purpose, according to one embodiment of the present invention, a method for manufacturing a pouch-type secondary battery may be provided, including a pre-aging step of assembling an electrode assembly by inserting it into a pouch case, injecting an electrolyte into the pouch case and sealing it; and, after the pre-aging step, a step of confirming an impregnation of the electrode assembly by dividing an outer surface of the pouch case into a plurality of analysis regions, pressurizing the plurality of analysis regions through a pad sensor having a plurality of nodes, and measuring a degree of impregnation of the electrolyte into the electrode assembly based on a deviation in pressures sensed through the plurality of nodes in the analysis regions.

[0044] After the above pre-aging step, a degassing step may be performed to initially charge and discharge the gas inside the pouch case to the outside; and after the degassing step, an OCV step may be performed to perform a quality inspection through open circuit voltage (OCV) measurement.

[0045] The above impregnation verification step can be performed after the degassing step.

[0046] The above impregnation verification step may be performed before the OCV step.

[0047] The above impregnation confirmation step can be performed while the pouch-type secondary battery is being transported to perform the degassing step or OCV step after the pre-aging step.

[0048] The above impregnation confirmation step can be performed while the pouch-type secondary battery is placed horizontally on a transfer table, or while a transfer gripper that vertically transfers the pouch-type secondary battery holds the pouch-type secondary battery.

[0049] Through one embodiment of the present invention, a method for manufacturing a pouch-type secondary battery can be provided, which can easily determine the degree of impregnation of an electrolyte and determine the completion of impregnation.

[0050] Through one embodiment of the present invention, a method for manufacturing a pouch-type secondary battery can be provided that can be easily applied to existing manufacturing devices and manufacturing processes to perform impregnation completion determination.

[0051] Through one embodiment of the present invention, a method for manufacturing a pouch-type secondary battery can be provided, which can easily determine whether optimal electrolyte impregnation has been performed in a given process by pressurizing the outer surface of the pouch-type secondary battery and sensing the rebound pressure at each location.

[0052] Through one embodiment of the present invention, a pouch-type secondary battery manufacturing device capable of easily determining whether impregnation is complete using the pouch-type secondary battery manufacturing device and a manufacturing method using the same can be provided.

[0053] Figure 1 illustrates a plan view of a pouch-type secondary battery.

[0054] Figure 2 illustrates a manufacturing process of a pouch-type secondary battery according to one embodiment of the present invention.

[0055] Figure 3 illustrates a front view of a pressurizing device according to one embodiment of the present invention.

[0056] Figure 4 illustrates a plane of a pad sensor that can be applied to one embodiment of the present invention.

[0057] Figure 5 illustrates an example in which the sensing value numerical value sensed at each node through the pad sensor is displayed.

[0058] Figure 6 shows an example in which the sensing value numerical value sensed at each node through the pad sensor is displayed through color change, and in particular, shows an example in an incomplete impregnation state.

[0059] Figure 7 shows an example in which the sensing value numerical value sensed at each node through the pad sensor is displayed through color change, and in particular, shows an example of an impregnation completion state.

[0060] FIG. 8 illustrates a front view of a pressurizing device applicable to one embodiment of the present invention, and particularly illustrates an example in which the pressurizing device is applied to a gripper.

[0061] Figure 9 illustrates an example in which the sensing value values ​​sensed by the pad sensor are displayed as being divided into an analysis area and an unanalyzed area, and in particular, illustrates an example in which impregnation is not completed.

[0062] Figure 10 illustrates an example in which the sensing value values ​​sensed by the pad sensor are displayed as being divided into an analysis area and an unanalyzed area, and in particular, an example of an incomplete impregnation state is illustrated.

[0063] Hereinafter, a method for manufacturing a secondary battery according to an embodiment of the present invention will be described in detail with reference to the attached drawings.

[0064] A pouch-type secondary battery can be manufactured by including a pre-aging process (S10) of assembling a pouch sheet, an electrode assembly, and an electrolyte into one secondary battery.

[0065] First, the electrode assembly is inserted into the pouch sheet, and the pouch sheet is sealed except for the inlet through which the electrolyte is injected. Then, the electrolyte is injected through the inlet, and the inlet is sealed. Therefore, the process from inserting the electrode assembly and electrolyte into the pouch case to the initial sealing of the pouch case can be referred to as the pre-aging process.

[0066] After the pre-aging process (S10) is completed, an activation process (S100) may be performed. This process activates the secondary battery by imparting electrical energy characteristics to it. It may also include subsequent processes such as stabilizing the secondary battery, inspecting for defects, and assigning grades. Only after the activation process (S100) is completed can the secondary battery be granted the performance of a rechargeable battery.

[0067] The activation process may include, in detail, an initial charge / discharge process, a degassing process, an aging process, an OCV process, and a sorting process.

[0068] Immediately after the pre-aging process is complete, pouch-type secondary batteries are in an inactive, discharged state and thus no longer function as batteries. The charge-discharge process is the process of charging and discharging a discharged secondary battery to give it the functionality of a battery.

[0069] Since the initial charge / discharge process is driven by chemical reactions, gas is generated as a side effect during the charge / discharge process. This gas can cause increased cell resistance, reduced capacity and lifespan, and poor appearance. Therefore, a degassing process (S40) is performed after the charge / discharge process to remove the gas.

[0070] According to the present embodiment, it is preferable to perform a pre-formation process (S20) for pressurizing the pouch-type secondary battery during or after the initial charge / discharge process. Through this, the gas inside the pouch can be easily captured in one location, i.e., an air pocket. In addition, the pre-formation process (S20) can ensure that the electrolyte filled inside the pouch is evenly distributed. Through this pre-formation process, the time required for the subsequent degassing process (S40) or aging process (S60) can be shortened.

[0071] According to the present embodiment, an impregnation verification process (S30) may be performed after the pre-aging process (S10) is completed. The impregnation verification process (S30) may be a process for confirming whether the electrolyte has been sufficiently impregnated throughout the positive and negative electrodes within the pouch. In addition, the impregnation verification process (S30) may be a process for confirming whether impregnation has been sufficiently performed at each location within the pouch.

[0072] As described below, the impregnation confirmation process (S30) can be performed by pressurizing the flat surface, i.e., the upper surface and the lower surface, of the pouch-type secondary battery (10). Therefore, the impregnation confirmation process can be referred to as a pressure sensing process. For example, it can be performed by supporting the lower surface as a whole and pressurizing the upper surface as a whole. Such a pressurizing method or device can be performed through a pre-formation jig that performs the pre-formation process. This is because the pre-formation jig is also performed by pressurizing the upper surface and the lower surface of the secondary battery.

[0073] Therefore, the impregnation verification process (S30) may be performed simultaneously with the pre-formation process (20) or as part of the pre-formation process (S20). For example, impregnation verification may be performed through the pressure distribution measured upon completion of the pre-formation process (S20).

[0074] While the conventional pre-formation process (S30) itself can be expected to have a qualitative impregnation enhancement effect, the impregnation degree can be quantitatively and non-destructively confirmed through the impregnation confirmation process (S30) according to one embodiment of the present invention. Furthermore, the impregnation confirmation process (S30) may not require a separate process time or independent device.

[0075] In addition, through the impregnation confirmation process (S30) according to one embodiment of the present invention, it is possible to confirm that sufficient impregnation has been performed before proceeding with the subsequent process, and to quickly detect defective products.

[0076] Meanwhile, the degassing process (S40) may be performed within a vacuum chamber to efficiently discharge the activated gas. In the degassing process (S40), a degas hole is formed in the pouch case, and the activated gas is discharged through the degas hole. Thereafter, the gas pocket in the pouch case is removed and secondary sealing is performed, thereby completing the degassing process (S3).

[0077] After the degassing process (S40) is completed, the formation process (S50), which is a process of activating the secondary battery and imparting electrical energy characteristics, can be performed.

[0078] The formation process (S50) optimizes the performance, stability, and lifespan of secondary batteries. It can be performed under extremely precise control of temperature, voltage, and current. Through the formation process (S50), secondary batteries can be given the functionality they need.

[0079] The aging process (S60) ensures that electrolyte evenly permeates the anode and cathode. It stabilizes the solid electrolyte interface (SEI) layer while storing under specific temperature, pressure, and humidity conditions, and measures the spontaneous discharge characteristics. This process allows for the identification of defective products.

[0080] The formation process (S50) may be performed while the aging process (S60) is in progress, and the aging process (S60) and the formation process (S50) may be performed sequentially and repeatedly.

[0081] The OCV process (S80) assesses battery quality by measuring open circuit voltage (OCV). OCV detects micro-shorts between the positive and negative electrodes during discharge of a secondary battery. If a micro-short occurs, the battery's open circuit voltage will change slightly, and by detecting this, the battery can be defective.

[0082] The OCV process (S80) may include an IR process that analyzes the internal resistance (IR) of a secondary battery based on frequency and current. Internal resistance is a factor that increases or decreases voltage when an externally applied current is applied. Therefore, since internal resistance affects charge / discharge efficiency, detection of high internal resistance may indicate a defect.

[0083] The OCV process and IR process can be referred to as the IR / OCV process or the OCV process.

[0084] The OCV process (S70) may not be a process performed separately from the formation process (S50) or the aging process (S60). That is, the OCV process may be performed repeatedly during the formation process and the aging process.

[0085] Meanwhile, the degassing process (S40) may be performed multiple times, and may also be performed after the aging process (S60) is completed. After the aging process is completed, the gas pocket may be removed from the pouch case to perform final sealing.

[0086] In the secondary battery manufacturing method according to the present embodiment, a pressure sensing process for confirming the degree of electrolyte impregnation or completion of impregnation may be performed after the aging process (S60). Specifically, the impregnation confirmation process (S70) may be performed after the degassing process (S40) is completed.

[0087] As described above, the impregnation verification process (S30) may be performed between the pre-aging process (S30) and the degassing process (S40), and may be referred to as the first impregnation verification process. Furthermore, the impregnation verification process (S70) may be performed after the degassing process (S40). This may be referred to as the second impregnation verification. Either the first or second impregnation verification may be performed, or both the first and second impregnation verifications may be performed.

[0088] It is preferable that the impregnation verification process (S70) be performed before the OCV process (S80). The OCV process (S80) may be performed multiple times, but it is preferable that the impregnation verification process (S30) be performed before the first OCV process. This is because the OCV process (S80) is a process for checking for micro-short circuits, and if a micro-short circuit has occurred, the impregnation verification may be unnecessary. In other words, a secondary battery in which impregnation is not completed before the OCV process (S80) is performed may be judged as defective, and thus the subsequent OCV process (S80) does not need to be performed.

[0089] The activation process (S100) may include a sorting process (S90). This sorting process (S90) may include a selection and grading process. It can be defined as a process that automatically grades secondary batteries based on quality and determines defects based on data from previous processes. Subsequently, secondary battery manufacturing can be completed through visual inspection, discharge, and packaging.

[0090] The inventors of the present invention have discovered that the degree of impregnation or the completion of impregnation can be confirmed by examining the difference in pressure or force applied to each location of the pouch case during the activation process (S100) performed after the pre-aging process (S10). Specifically, it was found that when impregnation reached a desirable level, the pressure variation across each location of the pouch case decreased. Therefore, it was found that impregnation could be easily and non-destructively confirmed.

[0091] The impregnation verification process (S30, S70) should be performed organically and continuously with other processes to increase the productivity of secondary battery manufacturing. In other words, it is crucial that the impregnation verification process not be separated from the continuous secondary battery manufacturing process or take a significant amount of time. To this end, the impregnation verification process (S30, S70) is preferably performed during the secondary battery transfer process between manufacturing processes or using a transfer device.

[0092] Hereinafter, with reference to FIGS. 3 and 4, a device for performing an impregnation verification process will be described in detail.

[0093] Figure 3 schematically illustrates an impregnation verification device according to one embodiment of the present invention. First, a cell (10) is placed on a plate (60). Of course, the plate (60) on which the cell (10) is placed may be moved and positioned on the impregnation verification device.

[0094] The cell (10) can be formed so that its horizontal and vertical lengths are relatively larger than its height. Accordingly, either the top or bottom surface of the cell (10) can be mounted on the plate (60). With the cell (10) mounted on the plate (60), the electrode leads (21, 22) can be positioned parallel to the plate (60).

[0095] Here, the plate (60) may be any one of a plate of a table on which the cell (10) is placed, a pallet on which the cell is placed and transported, or a formation jig.

[0096] A pressure plate (50) is provided at a position facing the above plate (60), and a pad sensor (40) may be provided on the lower surface of the pressure plate (50). The pressure plate (50) may pressurize a cell (10) placed on the plate (60) through the pad sensor (40). For example, the pressure plate (50) may pressurize the entire cell (10) as it descends. That is, the pad sensor (40) may be interposed between the cell (40) and the pressure plate (50).

[0097] At this time, it is preferable that the pressure plate (50) and pad sensor (40) be formed wider than the plane of the cell (10) so as to pressurize the entire outer surface of the cell.

[0098] The impregnation confirmation device (100) including the above-mentioned pressure plate (50) and pad sensor (40) can be positioned on a transport path for performing detailed processes of the activation process after the pre-aging process.

[0099] Fig. 4 illustrates an example of a pad sensor (40).

[0100] The pad sensor (40) may be formed to correspond to the outer shape of the cell (10), i.e., the plane of the pouch case. If the plane of the cell (10) is rectangular, the pad sensor (40) may be formed in a larger rectangular shape so as to cover the entire cell (10). Therefore, the size of the pad sensor (40) may vary depending on the size of the cell (10) for which impregnation confirmation is desired. In addition, the size of a single pad sensor (40) may be increased to perform impregnation confirmation of cells (10) of various sizes. This is because, when the size of the cell (10) is reduced, the cell (10) may be pressed only through a portion of the pad sensor (40) rather than the entire area. In other words, the area for measuring pressure in the pad sensor (10) may vary depending on the cell (10) model.

[0101] The above pad sensor (40) may be equipped with a plurality of nodes (41). The plurality of nodes (41) are equipped in a matrix form, and FIG. 4 illustrates a pad sensor (40) equipped with a 6X24 matrix, i.e., 144 nodes. Each node can form one channel and independently sense pressure. In other words, each node is one sensor, and these sensors form one pad to form a sensor module, which can be referred to as a pad sensor (40).

[0102] Each node can be fabricated as a pressure sensor, using a piezoelectric material that generates an electrical signal depending on the pressure. The piezoelectric material can be a piezoelectric polymer or piezoelectric ceramic.

[0103] A bezel (43) can be formed on at least three sides of the above plurality of nodes (41), and a connector (42) can be drawn out through one side. The sensing values ​​of each node can be transmitted to the control unit through the connector (42) to check the degree of impregnation or whether impregnation is complete.

[0104] Figure 5 shows the overall pressure values ​​sensed at each node.

[0105] When a cell (10) is pressurized through a pressure plate, the repulsive force of the cell (10) may vary depending on the location. That is, the force or pressure applied by each node to the cell (10) may vary. Such a sensing value or a converted numerical value of the sensing value may be displayed as shown in FIG. 5, for example.

[0106] The inventors discovered that by observing the difference in force or pressure applied at each location, it was possible to determine whether electrolyte impregnation was performed perfectly. In other words, it was confirmed that the lower the pressure difference, the more appropriate impregnation was performed.

[0107] Figures 6 and 7 illustrate examples of displaying pressure values ​​sensed through each node using numerical values ​​and color variations. For example, larger values ​​can be displayed in red, while smaller values ​​can be displayed in blue. Smaller values ​​can be displayed in a darker blue, while larger values ​​can be displayed in a darker red. Furthermore, by displaying gradual color variations between blue and red, the difference in pressure values ​​can be easily and intuitively identified.

[0108] These pressure value indications can be displayed to correspond to the shape of the pad sensor and the shape of the cell (10). The operator can intuitively determine whether impregnation is complete through the displayed pressure value sensing result (80). Of course, whether impregnation is complete can be automatically confirmed and determined through the controller.

[0109] As shown in Figure 6, when the degree of impregnation is low, the pressure value deviation increases. That is, the color difference is clearly evident by location. Conversely, as shown in Figure 7, when impregnation is complete, the pressure value deviation decreases. That is, the color difference by location is not significant.

[0110] Meanwhile, as shown in FIGS. 9 and 10, it is also possible to determine the completion of impregnation using some pressure values ​​rather than the pressure values ​​sensed from all nodes of the pad sensor (40).

[0111] In the partial pressure value sensing result (90), some areas can be designated as analysis areas (91) and the remaining areas can be designated as non-analyzed areas. For example, the central portion and both end portions of the cell (10) can be designated as non-analyzed areas, and some areas on both sides of the central portion of the cell (10) can be designated as analysis areas (91). The analysis area (91) can also be visually distinguished from other areas by a separate border.

[0112] As illustrated in Figure 9, the sensing values ​​within the two analysis areas (91) exhibit a significant deviation. The significant difference in color intuitively indicates a significant numerical deviation. Therefore, regardless of the pressure value in the unanalyzed area between the two analysis areas (91), it can be seen that impregnation is incomplete.

[0113] As illustrated in Figure 10, the sensing values ​​within the two analysis areas (91) exhibit a small deviation. The minimal difference in color intuitively indicates that the numerical deviation is small. Therefore, it can be seen that impregnation is complete, regardless of the pressure value in the unanalyzed area between the two analysis areas (91).

[0114] Here, the analysis and non-analyzed areas can be set differently for each cell model. In other words, the area where optimal impregnation completion can be determined can be set as the analysis area. Furthermore, setting the analysis area facilitates the logic for determining impregnation completion.

[0115] Meanwhile, the impregnation confirmation process according to one embodiment of the present invention may be performed immediately after the degassing process is completed or before the final side sealing process.

[0116] As illustrated in Fig. 8, the degassing process can be performed without removing the air pocket (33), and for this purpose, the pouch-shaped cell (10) can be supported by a gripper (70) in a horizontally erected state. A plurality of grippers (70) can be provided, and as illustrated, the cell (10) can be fixed by holding a plurality of points along the length of the cell (10).

[0117] The gripper (70) may include an upper gripper (71) and a lower gripper (72), which may face each other and press and fix the cell (10). At this time, a pad sensor may be provided on either the upper gripper (71) or the lower gripper (72).

[0118] Accordingly, multiple grippers can sense pressure while applying pressure to multiple areas for a single cell (10). For example, one gripper can correspond to one analysis area. That is, the location of the analysis area can vary depending on the position at which the gripper holds the cell (10).

[0119] Meanwhile, a barcode or QR code is displayed on the surface of each cell (10), so that information on the corresponding cell (10) can be easily identified. That is, information on the cell where the current impregnation confirmation process is being performed can be identified, and the judgment result, such as impregnation completion or non-compliance, of the corresponding cell can be stored.

[0120] As described above, pad sensors for impregnation verification can be installed on devices such as preformation jigs or cell grippers. That is, preformation jigs and cell grippers may be essential devices used in the manufacturing process of pouch-type secondary batteries. Therefore, by installing pad sensors on these devices, an additional impregnation verification process can be performed.

[0121] As described in the detailed description of the invention.

Claims

1. A pre-aging step of assembling the electrode assembly by inserting it into a pouch case and injecting the electrolyte into the pouch case and sealing it; and A method for manufacturing a pouch-type secondary battery, comprising: after the pre-aging step, pressurizing the outer surface of the pouch case through a pad sensor having a plurality of nodes, and checking the degree of impregnation of the electrolyte into the electrode assembly based on the deviation of the pressures sensed through the plurality of nodes.

2. In paragraph 1, A method for manufacturing a pouch-type secondary battery, characterized in that the pad sensor is interposed between the pouch case and the pressure plate so that the pad sensor presses the outer surface of the pouch case by the pressure plate.

3. In paragraph 2, A method for manufacturing a pouch-type secondary battery, characterized in that the entire pad sensor presses the outer surface of the pouch case by the pressurizing plate.

4. In paragraph 3, A method for manufacturing a pouch-type secondary battery, characterized in that the plurality of nodes are provided in a grid shape on the pad sensor so as to sense pressure independently of each other.

5. In paragraph 4, A method for manufacturing a pouch-type secondary battery, characterized in that the pressure sensed at each of the plurality of nodes is displayed numerically on the image of the pad sensor.

6. In paragraph 5, A method for manufacturing a pouch-type secondary battery characterized in that different colors are displayed depending on the size of the above numerical value.

7. In paragraph 5, A method for manufacturing a pouch-type secondary battery, wherein the above plurality of nodes are divided into a plurality of analysis areas and non-analyzed areas, and the degree of impregnation is measured based on the pressure difference between the analysis areas.

8. In paragraph 1, A method for manufacturing a pouch-type secondary battery, characterized in that the pad sensor is provided on a gripper that presses the upper and lower surfaces of the pouch case to fix the pouch case.

9. In paragraph 8, A method for manufacturing a pouch-type secondary battery, wherein the gripper includes an upper gripper that presses the upper surface of the pouch case and a lower gripper that presses the lower surface of the pouch case, and wherein the pad sensor is provided on either the upper gripper or the lower gripper.

10. In paragraph 9, A method for manufacturing a pouch-type secondary battery, characterized in that the gripper is provided in multiple numbers to form multiple analysis areas by varying the pressing positions on the outer surface of the pouch case.

11. In paragraph 10, A method for manufacturing a pouch-type secondary battery, characterized in that the gripper is provided in plurality corresponding to the plurality of analysis areas.

12. In paragraph 11, A method for manufacturing a pouch-type secondary battery, characterized in that the plurality of grippers are arranged to be parallel to each other and are arranged to grip the pouch-type secondary battery while crossing it.

13. In paragraph 1, After the above pre-aging step, a degassing step is included to initially charge and discharge the gas inside the pouch case to the outside. A method for manufacturing a pouch-type secondary battery, characterized in that the above impregnation confirmation step is performed after the degassing step.

14. In paragraph 13, After the above degassing step, an OCV step is included to perform quality inspection through open circuit voltage (OCV) measurement, A method for manufacturing a pouch-type secondary battery, characterized in that the above impregnation confirmation step is performed before the above OCV step.

15. A pre-aging step of assembling the electrode assembly by inserting it into a pouch case and injecting an electrolyte into the pouch case and sealing it; A method for manufacturing a pouch-type secondary battery, comprising: after the pre-aging step, dividing the outer surface of the pouch case into a plurality of analysis areas, pressurizing the plurality of analysis areas through a pad sensor having a plurality of nodes, and measuring the degree of impregnation of the electrolyte into the electrode assembly based on the deviation of the pressures sensed through the plurality of nodes in the analysis areas.

16. In paragraph 15, After the above pre-aging step, a degassing step for initially charging and discharging the gas inside the pouch case to the outside; and A pouch-type secondary battery manufacturing method characterized in that, after the above degassing step, it includes an open circuit voltage (OCV) step for performing quality inspection through OCV measurement.

17. In paragraph 16, A method for manufacturing a pouch-type secondary battery, characterized in that the above impregnation confirmation step is performed after the degassing step.

18. In paragraph 16, A method for manufacturing a pouch-type secondary battery, characterized in that the above impregnation confirmation step is performed before the above OCV step.

19. In paragraph 16, A method for manufacturing a pouch-type secondary battery, characterized in that the impregnation confirmation step is performed while the pouch-type secondary battery is being transported to perform the degassing step or the OCV step after the pre-aging step.

20. In paragraph 17, A method for manufacturing a pouch-type secondary battery, characterized in that the above impregnation confirmation step is performed while the pouch-type secondary battery is placed horizontally on a transfer table or while a transfer gripper that vertically transfers the pouch-type secondary battery holds the pouch-type secondary battery.

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