Method and apparatus for activating battery cell

Abstract

Disclosed are a method and apparatus for activating a battery cell, capable of preventing problems in which, during an activation process, at least a portion of a separator is detached, resulting in a folding phenomenon, as pre-aging proceeds after injection of an electrolyte, and after a degassing process, separator folding manifests as surface wrinkles on a cell. The method for activating a battery cell is a process performed after a pre-aging process has been performed and before a degassing process is performed, during a process of activating a battery cell, and comprises the steps of: (a) fixing a pre-aged battery cell; and (b) pressing the fixed battery cell while moving a pressing plate in the overall width direction of the fixed battery cell.

Description

Method and device for activating a battery cell

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2025-0003095 dated January 8, 2025, and all contents disclosed in the document of said Korean patent application are incorporated herein as part of this specification.

[0002] The present invention relates to a method and apparatus for activating a battery cell, and more specifically, to a method and apparatus for activating a battery cell that can prevent a problem in which at least a portion of the separator detaches and a folding phenomenon occurs as pre-aging proceeds after the injection of an electrolyte during the activation process, and the separator folding manifests as surface wrinkles of the cell after the degassing process.

[0003] With the explosive growth in technological development and demand for mobile devices and automobiles, more research is being conducted on rechargeable batteries that possess high energy density, discharge voltage, and excellent output stability. Examples of such rechargeable batteries include lithium-sulfur batteries, lithium-ion batteries, sodium-ion batteries, and lithium-ion polymer batteries. Furthermore, these batteries can be classified into cylindrical, prismatic, and pouch types based on their shape; among these, interest and demand for pouch-type battery cells are gradually increasing. Pouch-type battery cells can be stacked with high integration density, offer high energy density per unit weight, are inexpensive, and are easy to deform. Consequently, pouch-type battery cells can be manufactured in shapes and sizes applicable to various fields, such as mobile devices and automobiles.

[0004] Conventional pouch-type secondary batteries are manufactured by stacking electrode assemblies, which generally include a positive electrode, a negative electrode, and a separator interposed between them, and then housing them in a battery case. In this way, the electrode assemblies housed in the battery case can be specifically classified into a jelly-roll type, which is wound with a separator interposed between a sheet-type positive electrode and a negative electrode coated with an active material; a stack type, which is sequentially stacked with a plurality of positive and negative electrodes interposed with a separator; and a stack / folding type, which is wound with a long separator (or a positive electrode is wound with a monocell in which a unit negative electrode is interposed between two sheet-type separators).

[0005] As such, a conventional pouch-type secondary battery is basically manufactured by performing a process of stacking multiple electrodes, and generally, it is manufactured through a process such as using a mechanism to stack multiple electrodes to produce an electrode assembly and then accommodating it in a pouch.

[0006] Once the assembly process of battery cells for manufacturing such pouch-type secondary batteries, that is, the process of manufacturing the electrode assembly of the battery cells, is completed, the process enters the activation process (or formation process) in which the battery is activated with electrical energy and its safety is verified. In this activation stage, all processes are carried out with large-scale automation, and in particular, the process proceeds by repeating aging and charging / discharging.

[0007] More specifically, the battery cell assembly process includes a process for assembling electrodes and separators, etc., and a subsequent packaging process. At this time, the battery cell may be, for example, a Z-Stacking type cell or a Lamination & Stacking type cell.

[0008] And, the above activation process can be completed, for example, by injecting an electrolyte into the cell, followed by a pre-aging process, a high pressure current detector (HPCD) process, a pressurized preheating (PP) process, a jig formation process, a high temperature aging process, a room temperature aging process, a degassing process, a secondary jig formation process, a shipment aging process, a double side folding (DSF) process, and an end of line (EOL) process.

[0009] However, when a battery cell into which the electrolyte has been injected undergoes a pre-aging process that allows the electrolyte to permeate into the interior of the cell (i.e., to cause wetting), at least a portion of the separator may detach (or unravel) and fold, which causes a problem where the separator folding manifests as wrinkles on the outer surface of the cell after the degassing process.

[0010] Although the industry is aware of this problem, the current situation is that we are unable to come up with fundamental solutions, as we can only determine whether to discard cells based on external inspections.

[0011] Therefore, a method is required to improve the folding phenomenon of the separator membrane before it manifests as wrinkles on the outer surface of the cell, thereby enhancing process efficiency while reducing costs.

[0012] Accordingly, the objective of the present invention is to provide a method and apparatus for activating a battery cell that can prevent the problem in which at least a portion of the separator detaches and folds as pre-aging proceeds after the electrolyte injection during the activation process, and the separator folding manifests as wrinkles on the surface of the cell after the degassing process.

[0013] To achieve the above objective, the present invention provides a method for activating a battery cell, comprising a process performed after a pre-aging process and before a degassing process during a process for activating a battery cell, the method comprising: (a) a step of fixing a pre-aged battery cell; and (b) a step of moving a pressure plate in the full width direction of the fixed battery cell and applying pressure.

[0014] In addition, the present invention provides an activation device for a battery cell comprising: a cell fixing unit for fixing a battery cell; and a pressure plate that moves in the full width direction of the battery cell fixed through the cell fixing unit and applies pressure.

[0015] The method and apparatus for activating a battery cell according to the present invention have the advantage of preventing the problem in which at least a portion of the separator detaches and causes a folding phenomenon as pre-aging proceeds after the injection of the electrolyte during the activation process, and the separator folding manifests as surface wrinkles of the cell after the degassing process.

[0016] The following drawings attached to this specification illustrate embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0017] FIG. 1 is a front view showing the direction in which the surface of a battery cell is pressed using an activation device according to one embodiment of the present invention.

[0018] FIG. 2 is a front view showing the surface of a battery cell being pressed using an activation device according to one embodiment of the present invention.

[0019] Figure 3 is an image showing that there is a difference in wetting speed depending on the location within the battery cell.

[0020] FIG. 4a is a schematic diagram of a pressure plate with air holes formed according to one embodiment of the present invention, and FIG. 4b is a schematic diagram of a pressure plate with a heat source attached to one side according to one embodiment of the present invention.

[0021] Figure 5 shows the exterior (a) and interior (b) of a pouch-type battery cell activated according to a conventional method.

[0022] Figure 6 is an external image of a pouch-type battery cell activated according to a conventional method.

[0023] Terms and words used in this specification and claims shall not be interpreted as being limited to their ordinary or dictionary meanings, but shall be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0024] Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely one embodiment of the present invention and do not represent all of the technical ideas of the present invention; thus, it should be understood that there are various equivalents and modifications that can replace them at the time of filing this application.

[0025] In addition, in describing the present invention, if it is determined that a description of related known components or functions may obscure the essence of the invention, such detailed description is omitted.

[0026] The present invention will be described in detail below with reference to the attached drawings.

[0027] FIG. 1 is a front view showing the direction in which the surface of a battery cell is pressed using an activation device according to one embodiment of the present invention, and FIG. 2 is a front view showing the appearance of pressing the surface of a battery cell using an activation device according to one embodiment of the present invention.

[0028] Referring to FIGS. 1 and 2, the method for activating a battery cell according to the present invention is a process performed after a pre-aging process is performed and before a degassing process is performed during the process of activating a battery cell (100), and includes (a) a step of fixing the pre-aged battery cell (100), and (b) a step of moving a pressure plate (200) in the full width direction of the fixed battery cell (100) and applying pressure.

[0029] A conventional pouch-type secondary battery, as generally known, is finalized through a battery cell assembly process that includes a process of manufacturing an electrode assembly using electrodes and separators, a subsequent packaging process, and an activation process (or formation process) that involves repeating aging and charging / discharging to activate the battery with electrical energy and verify safety.

[0030] At this time, the battery cell may be a type of battery cell applicable to a conventional pouch-type secondary battery, such as a Z-Stacking type cell or a Lamination & Stacking type cell.

[0031] In addition, the above activation process is performed with the electrolyte injected into the battery cell. Although there is no specific restriction on the timing of the electrolyte injection, it is preferable to inject it during the assembly process or before the activation process, and it may be more preferable to inject it during the assembly process. For example, the prepared electrode assembly may be placed inside a battery case, the electrolyte may be injected, and then the battery case may be sealed to enter the activation process.

[0032] The activation process performed on the battery cells that have undergone the assembly process described above can generally be completed through a pre-aging process, a high pressure current detector (HPCD) process, a pressurized preheating (PP) process, a jig formation process, a high temperature aging process, a room temperature aging process, a degassing process, a secondary jig formation process, a shipment aging process, a double side folding (DSF) process, and an end of line (EOL) process.

[0033] The above pre-aging process is a process of storing the battery in an environment with a certain temperature and humidity before the activation process so that the electrolyte injected into the battery cell can permeate (or sufficiently impregnate) the positive and negative electrodes of the battery, respectively; specifically, it is a process to facilitate the movement of ions between the positive and negative electrodes of the battery by evenly dispersing the electrolyte inside the battery.

[0034] Furthermore, the aforementioned degassing process is designed to remove gases that are inevitably generated inside the battery due to repeated aging and charging. In particular, for pouch-type batteries, the degassing process must be included because gases are generated from side reactions of the electrolyte starting from the initial charging process.

[0035] However, when a battery cell injected with electrolyte undergoes a pre-aging process that allows the electrolyte to permeate into the interior of the cell (i.e., to achieve wetting), at least a portion of the separator may detach (or unravel), causing a folding phenomenon. In this case, a problem arises where the separator folding manifests as wrinkles on the outer surface of the cell after the degassing process.

[0036] Accordingly, the applicant has invented a technology that improves the folding phenomenon of the separator membrane before it manifests as wrinkles on the outer surface of the cell, thereby improving process efficiency while reducing costs. Below, the means of solution will be explained in detail.

[0037] The method for activating a battery cell according to the present invention must be performed after a pre-aging process is performed and before a degassing process is performed during the process of activating the battery cell (100).

[0038] In addition, the activation method of the battery cell is preferably performed after the High Pressure Current Detector (HPCD) process is performed and before the Pressurized Preheating (PP) process is performed, among the periods after the pre-aging process is performed and before the degassing process is performed.

[0039] The above high voltage current measurement (HPCD) process and the above pressurization / preheating (PP) process are both performed between the above pre-aging process and the above primary charge / discharge (Jig Formation) process or degassing process.

[0040] To briefly explain these processes, the high voltage current measurement (HPCD) process is a process that applies a certain voltage to the battery cell to measure the leakage current of the cell, and can determine whether defects such as tearing or folding have occurred in the separator.

[0041] In addition, the above pressurization / preheating (PP) process is a process that applies heat and pressure to the battery cell, and by providing cell adhesion in a wet environment, it can prevent bending of the cell.

[0042] As explained above, the method for activating a battery cell according to the present invention is preferably performed 'after the pre-aging process is performed and before the degassing process is performed,' specifically 'after the high-voltage current measurement (HPCD) process is performed and before the pressurization / preheating (PP) process is performed.' This is because it must be established beforehand that there are no defects in the separator through the high-voltage current measurement (HPCD) process, and the means for solving the problem of the present invention must operate before the imparting of adhesion by the pressurization / preheating (PP) process.

[0043] According to the above, in order to improve the folding phenomenon of the separator before it manifests as wrinkles on the outer surface of the battery cell (100), the pre-aged battery cell must first be fixed (step a).

[0044] Specifically, the battery cell (100) can be fixed by the cell fixing unit (not shown) by unloading the pre-aged battery cell from a tray (not shown) and placing it into the cell fixing unit.

[0045] At this time, it is preferable to fix the pre-aged battery cell (100) in a vertically positioned state, as shown in FIG. 1.

[0046] Furthermore, it is more preferable that the pre-aged battery cell (100) be fixed in a vertically positioned state such that the degassing portion (104) is located above the electrode assembly housing portion (102) with respect to the vertical direction.

[0047] However, the fixing of the battery cell (100) using the above-mentioned cell fixing unit is merely an example, and there are no special limitations on the means for fixing the battery cell as long as the battery cell does not detach while standing upright in a vertical direction such that the degassing part (104) is positioned above the electrode assembly housing part (102) with respect to the vertical direction.

[0048] If the above-mentioned pre-aged battery cell (100) is fixed so as not to move, the pressure plate (200) must be moved in the full width direction of the fixed battery cell (100), that is, in other words, the pressure plate (200) must be moved and pressure applied from one end surface (d1) of the fixed battery cell (100) to the other end surface (d2) in the direction where the degassing part (104) is located (step b).

[0049] In this way, by moving the pressure plate (200) from one end surface (d1) of the battery cell (100) to the other end surface (d2) in the direction where the degassing part (104) is located and applying pressure, the electrolyte contained in the cell can be flowed in a certain direction, so it is possible to alleviate the folding phenomenon of the separator and also improve the wetting property between the electrode and the electrolyte.

[0050] That is, Figure 3 is an image showing that there is a difference in wetting speed depending on the location within the battery cell. As shown in Figure 3, a difference in wetting speed occurs depending on the location even within a single battery cell. The present invention can increase the impregnation effect even to the 'center of the cell,' where the wetting speed is slowest, by inducing the flow of the electrolyte through pressurization even after the pre-aging process.

[0051] In addition, since the folding phenomenon of the separator is mitigated before the pressurization / preheating (PP) process is performed, it is possible to prevent or minimize the problem of the separator folding manifesting as surface wrinkles of the cell even after the degassing process.

[0052] Meanwhile, the direction in which the above-mentioned pressure plate (200) is moved must be a direction that intersects with the direction in which the electrode tabs (110a, 110b) of the battery cell (100) are drawn out, as shown in FIG. 1, or the full width direction of the battery cell (wherein the full length direction means the direction in which the two electrode tabs face each other).

[0053] In addition, as described above, the pre-aged battery cell (100) must be positioned vertically such that the degassing portion (meaning 'a portion located at one end of the electrode assembly housing and protruding or extending outwardly,' 104) is located above the electrode assembly housing (102) based on the vertical direction.

[0054] And in this state, as shown in FIG. 2, the electrode assembly housing (102) must be raised by applying pressure with a pressure plate (200) from the bottom (d1) of the electrode assembly housing (102) in the vertical direction to the top (d2) of the electrode assembly housing in the direction where the degassing part (104) is located.

[0055] In other words, the pressure plate (200) rises parallel to the front or rear of the battery cell (100) while in contact with the front or rear of the battery cell (100).

[0056] In this way, the reason for pressing the pressure plate (200) from the bottom (d1) of the electrode assembly housing (102) while the battery cell (100) is positioned so that the degassing section (104) is positioned above the electrode assembly housing (102) is to facilitate productivity in terms of inputting vertically into the subsequent process (i.e., simplifying equipment operation).

[0057] Therefore, if the degassing section (104) is located below the electrode assembly housing section (102), or if the pressure plate (200) is lowered by applying pressure from the top (d2) of the electrode assembly housing section (102), the advantage may be relatively small.

[0058] In addition, the above-mentioned pressure may be performed by two pressure plates. That is, as shown in FIGS. 1 and 2, in addition to positioning one pressure plate (200) on the front of the electrode assembly housing (102), another pressure plate (not shown) may also be positioned on the rear of the electrode assembly housing (102) to apply pressure simultaneously on both sides of the electrode assembly housing (102).

[0059] That is, the pressure plate (200) is provided on each side of the electrode assembly housing (102) to apply pressure to the electrode assembly housing (102).

[0060] In addition, the above step (b) may be repeated two or more times.

[0061] For example, when the first pressurization is completed by raising the pressure plate (200), the raised pressure plate (200) is separated from and lowered from the surface (d2) of the electrode assembly housing (102), and then brought into contact with the lower surface (d1) of the vertical reference electrode assembly housing (102) again to re-pressurize the electrode assembly housing (102) of the battery cell (100).

[0062] In this way, if the pressure according to step (b) above is repeated two or more times, there is an advantage in that the impregnation effect of the cell can be maximized.

[0063] Additionally, the pressure applied to the electrode assembly housing (102) through the pressure plate (200) may be 0.2 to 0.5 MPa, preferably 0.2 to 0.4 MPa. If the pressure applied to the electrode assembly housing (102) is less than 0.2 MPa, the degree of relief of separator folding and the degree of electrolyte flow may be negligible. Furthermore, if the pressure applied to the electrode assembly housing (102) exceeds 0.5 MPa, there is a risk of defects occurring, such as damage to the cell due to excessive pressure.

[0064] The pressure plate (200) is preferably an insulator, and for example, the pressure plate (200) may be made of a resin-based compound. The resin-based compound may be one or more selected from the group consisting of all resin compounds that do not conduct electricity or heat, such as natural resins and synthetic resins. If the pressure plate (200) is not an insulator, it may cause scratches on the internal structure and external surface of the cell.

[0065] In addition, it is preferable that the pressure plate (200) be ultra-thin. Also, the thickness of the pressure plate (200) may be 0.05 to 2 mm, preferably 0.05 to 1 mm, more preferably 0.07 to 0.5 mm, and most preferably 0.09 to 0.3 mm. However, this is based on a pouch cell having a general width and thickness, and if a pouch cell of a size not commonly used is used, the thickness of the pressure plate may be varied to fit the pouch cell.

[0066] Also, although the above-mentioned pressure plate (200) is depicted in a square shape in the drawing, this is merely an arbitrary shape shown to aid understanding, and there are no special restrictions on the shape as long as the same pressure effect can be produced.

[0067] Meanwhile, the pressure plate (200) may be formed with one or more air holes (210) perforated to minimize friction with the surface of the electrode assembly housing (102) (or, the pressure plate (200) may include one or more air holes (210).

[0068] FIG. 4a is a schematic diagram of a pressure plate having air holes formed according to one embodiment of the present invention. As shown in FIG. 4a, a plurality of air holes (210) may be formed in the pressure plate (200) at regular intervals, forming columns and rows.

[0069] There is no particular limit to the number of air holes (210) and it can be varied depending on the area or environment of the pressure plate (200).

[0070] In addition, when multiple air holes (210) are formed in the pressure plate (200) as shown in FIG. 4a, the size of each of the air holes (210) may be the same or different, but in order to ensure balanced and stable rise of the pressure plate (200) when pressurized, it is preferable that the sizes of the multiple air holes (210) be similar or the same without significant difference from each other.

[0071] As a result of conducting various experiments over a long period of time by the applicant, it was confirmed that the diameter of each of the air holes (210) is suitable to be 0.2 to 1.0 mm, and preferably 0.3 to 0.5 mm.

[0072] If the diameter of each of the air holes (210) is less than 0.2 mm, the effect of reducing friction with the surface of the electrode assembly housing may be negligible. Additionally, if the diameter of each of the air holes (210) exceeds 1.0 mm, the space in the pressure plate becomes excessively wide, and the pressure effect may be reduced.

[0073] Meanwhile, the above-mentioned pressure plate (200) may further include a heat source capable of flowing the electrolyte more smoothly, and may also be equipped with an operating part capable of controlling the heat source and a sensor required for checking the temperature.

[0074] FIG. 4b is a schematic diagram of a pressure plate with a heat source attached to one side according to an embodiment of the present invention. For example, the heat source may be located in the form of a heating pad (220) attached to one side of the pressure plate as shown in FIG. 4b, or it may be located inside the pressure plate (200). There are no special restrictions on the form in which the heat source is included as long as the heat source can be delivered to the electrode assembly housing. In addition, the pressure plate (200) may be used in a state heated by an external heat source, and the heating pad (220) may perform this role.

[0075] To provide further explanation regarding the heating pad (220), the heating pad (220) may be attached to one side of the pressure plate (200) as shown in FIG. 4b, or may be attached to two or more sides of the pressure plate (200), and there are no special restrictions on the number or attachment location.

[0076] Additionally, the heating pad (220) may come into contact with the surface of the electrode assembly housing (102) together with the pressure plate (200), may come into contact with the surface of the electrode assembly housing (102) alone, and may also serve only to heat the pressure plate (200) without coming into contact with the surface of the electrode assembly housing (102).

[0077] The form of the heat source included inside the above-mentioned pressure plate (200) can be very diverse. For example, a self-heating heater rod (Cartridge Heater Pipe, not shown) can be provided inside the above-mentioned pressure plate (200).

[0078] Here, regarding the configuration and heating principle of the heater rod, the interior of the heater rod may be equipped with a ceramic core that forms the shape of a heater rod and acts as a support rod, a heating coil (material: nichrome, etc.) that surrounds the ceramic core, and a wire that supplies electricity to the heating coil. By supplying electricity to the heating coil through the wire, heat is generated in the ceramic core. Additionally, one or more heater rods may be included inside the pressure plate (200), and the number may vary depending on the size of the pressure plate (200).

[0079] The temperature applied to the electrode assembly housing (102) through the above heat source may be 70 to 100°C, preferably 70 to 80°C. If the temperature applied to the electrode assembly housing (102) is less than 70°C, the purpose of making the electrolyte flow more smoothly may be diminished. In addition, if the temperature applied to the electrode assembly housing (102) exceeds 100°C, there is a risk of damage, such as the pouch and cell melting due to excessive heat.

[0080] Meanwhile, while step (b) is being performed, air may be injected for the purpose of minimizing friction between the pressure plate (200) and the surface of the electrode assembly housing (102).

[0081] Accordingly, in this case, an air layer is formed between the pressure plate (200) and the surface of the electrode assembly housing (102), and the air layer acts as an air lubricant to relieve friction that occurs during pressure application.

[0082] In addition, if air is injected while using the previously described 'pressure plate with air holes,' an enhanced friction reduction effect can be achieved due to the synergistic effect.

[0083] According to the above, when the pressurization according to step (b) is completed, the fixed battery cell can be separated from the cell fixing unit, etc., and then loaded back into the tray and introduced into the remaining activation process.

[0084] Next, an activation device for a battery cell according to the present invention will be described.

[0085] The activation device of the battery cell comprises a cell fixing unit (not shown) for fixing a pre-aged battery cell (100), and a pressure plate (200) that moves in the full width direction of the battery cell (100) fixed through the cell fixing unit (or moves from one end surface (d1) to the other end surface (d2) in the direction where the degassing part (104) is located) and applies pressure.

[0086] The cell fixing unit is a member for fixing a pre-aged battery cell (100), and there are no special restrictions on its shape or the mechanism for fixing the battery cell; however, it must include a means to fix the pre-aged battery cell (100) in a vertically positioned state such that the degassing part (104) is located above the electrode assembly housing part (102) with respect to the vertical direction.

[0087] Furthermore, the timing at which the activation device of the battery cell (100) is substantially used, the configuration of the pressure plate (200), and the method of applying pressure using the pressure plate (200) are replaced by the above-mentioned methods.

[0088] Meanwhile, if the above-mentioned pressure plate (200) further includes a heat source, an operating part capable of controlling the heat source and a sensor required for temperature checking may be provided at an appropriate location, and in particular, the temperature check sensor must be located adjacent to the surface of the electrode assembly housing (102) so that immediate signal transmission is possible.

[0089] In addition, as described above, during pressurization using the pressure plate (200), air may be injected for the purpose of minimizing friction between the pressure plate (200) and the surface of the electrode assembly housing (102), and the air may be supplied using a separate supply line and nozzle, but is not limited thereto.

[0090] The secondary battery activated through the above method and apparatus for activating battery cells can be used not only as a battery cell used as a power source for small devices, but also as a unit cell in a medium-to-large battery module containing multiple battery cells. The present invention also provides a battery module containing two or more secondary batteries electrically connected (in series or in parallel). Of course, the number of secondary batteries included in the battery module can be adjusted in various ways considering the application and capacity of the battery module.

[0091] Furthermore, the present invention provides a battery pack in which the battery module is electrically connected according to the art of the art. The battery module and battery pack may be used as a power source for one or more medium-to-large devices, including a power tool; an electric vehicle (EV), a hybrid electric vehicle (HEV), and a plug-in hybrid electric vehicle (PHEV); an electric truck; an electric commercial vehicle; or a power storage system, but are not limited thereto.

[0092] Preferred embodiments are presented below to aid in understanding the present invention; however, the following embodiments are merely illustrative of the invention, and it is obvious to those skilled in the art that various changes and modifications are possible within the scope and spirit of the invention, and that such changes and modifications fall within the scope of the appended claims.

[0093] [Example 1] Activation of a battery cell

[0094] First, Z-stacking type battery cells that had undergone the pre-aging process and the High Pressure Current Diagnosis (HPCD) process were unloaded from the tray and secured with a cell fixing unit; however, they were fixed in a vertically upright position such that the degassing portion was positioned above the electrode assembly housing portion relative to the vertical direction.

[0095] Next, a plate was brought into contact with the surface of the fixed battery cell and pressed, and at this time, the electrode assembly housing was pressed while raising the plate in the full width direction of the battery cell.

[0096] Finally, after pressurization is completed, the battery cell is separated from the cell fixing unit and loaded back into the tray, and then the product is manufactured by sequentially undergoing remaining activation processes such as pressurization / preheating (PP) process, primary charge / discharge process, high-temperature aging process, room-temperature aging process, degassing process, secondary charge / discharge process, shipping aging process, sealing part folding (DSF) process, and end-of-life (EOL) process.

[0097] [Example 2] Activation of battery cell

[0098] The procedure was performed in the same manner as Example 1 above, except that after the first pressurization was completed, the raised plate was separated from and lowered from the surface of the electrode assembly housing, and then brought into contact with the lower surface of the vertical reference electrode assembly housing to re-pressurize the electrode assembly housing of the battery cell.

[0099] [Example 3] Activation of battery cell

[0100] The procedure was performed in the same manner as Example 1, except that one plate was placed on each side of the electrode assembly housing and the electrode assembly housing was pressed from each side.

[0101] [Example 4] Activation of battery cell

[0102] The procedure was performed in the same manner as Example 1 above, except that a plate was used in which multiple air holes were formed at regular intervals in rows and columns.

[0103] [Example 5] Activation of battery cell

[0104] The procedure was performed in the same manner as Example 1 above, except that a plate with a heating pad attached to one side was used.

[0105] [Example 6] Activation of battery cell

[0106] The procedure was performed in the same manner as Example 1 above, except that air was injected to minimize friction while raising the plate and pressurizing the electrode assembly housing.

[0107] [Comparative Example 1] Activation of a battery cell

[0108] The assembled Z-stacking type battery cell was sequentially fed into a conventional activation method, namely a pre-aging process, a high-voltage current measurement (HPCD) process, a pressurization / preheating (PP) process, a primary charge / discharge process, a high-temperature aging process, a room-temperature aging process, a degassing process, a secondary charge / discharge process, a shipping aging process, a sealing part folding (DSF) process, and an end-of-life (EOL) process to be commercialized.

[0109] [Test Example 1] Evaluation of Battery Cell Appearance

[0110] Visual appearance evaluation was performed on each battery cell activated in Examples 1 to 6 and Comparative Example 1.

[0111] FIG. 5 shows the exterior (a) and interior (b) of a pouch-type battery cell activated according to a conventional method, and FIG. 6 shows the exterior (a to d) images of a pouch-type battery cell activated according to a conventional method.

[0112] First, the battery cell of Comparative Example 1, activated according to a conventional method, showed a wrinkled appearance on its surface as shown in FIG. 5a. Upon inspecting the inside of the cell, it was confirmed that the separator was partially detached and folded in several places as shown in FIG. 5b. Furthermore, even when repeated experiments were conducted under the same environment or with lamination / stacking type cells, a wrinkled appearance on the surface was observed as shown in FIG. 6a to 6d.

[0113] On the other hand, the battery cell of Example 1, in which the electrode assembly housing of the battery cell was pressed at a specific activation time according to the present invention, had a smooth shape with no wrinkles observed on the surface.

[0114] Therefore, it was confirmed that when a specific method of pressurization is applied at the activation time specified in the present invention, the electrolyte inside the cell flows, thereby alleviating the folding phenomenon of the separator, and that no wrinkles appear on the surface of the cell even after the degassing process is performed.

[0115] [Explanation of the symbol]

[0116] 100: Battery cell

[0117] 102: Electrode assembly housing

[0118] 104: Degassing Department

[0119] 110a, 110b: Electrode tabs

[0120] 200: Pressure plate

[0121] 210: Air hole

[0122] 220: Heating pad

Claims

1. A process performed after the pre-aging process and before the degassing process during the process of activating the battery cell, (a) a step of securing pre-aged battery cells; and (b) A method for activating a battery cell comprising the step of moving a pressure plate in the full width direction of the fixed battery cell and applying pressure.

2. A method for activating a battery cell according to claim 1, wherein the pre-aged battery cell is fixed in a vertically upright position such that the degassing portion is located above the electrode assembly housing portion with respect to the vertical direction.

3. A method for activating a battery cell according to claim 2, characterized by raising the pressure plate in the full width direction of the battery cell and pressing the electrode assembly housing.

4. A method for activating a battery cell according to claim 3, wherein the pressure plate rises parallel to the front or rear surface of the battery cell while in contact with the front or rear surface of the battery cell.

5. A method for activating a battery cell according to claim 4, wherein the pressure plate is provided on each of the two sides of the electrode assembly housing and pressurizes the electrode assembly housing.

6. A method for activating a battery cell according to claim 4, wherein step (b) is repeated two or more times, and when the first pressurization is completed by raising the pressurizing plate, the raised pressurizing plate is separated from and lowered from the surface of the electrode assembly housing, and then the electrode assembly housing is re-pressurized by bringing it into contact with the lower surface of the vertical reference electrode assembly housing again.

7. A method for activating a battery cell according to claim 4, characterized in that the pressure applied to the electrode assembly housing through the pressure plate is 0.2 to 0.5 MPa.

8. A method for activating a battery cell according to claim 4, wherein the pressure plate comprises one or more air holes to minimize friction with the surface of the electrode assembly housing.

9. A method for activating a battery cell according to claim 8, characterized in that the pressure plate has a plurality of air holes formed at regular intervals in rows and columns.

10. A method for activating a battery cell according to claim 9, characterized in that the diameter of each air hole is 0.2 to 1.0 mm.

11. A method for activating a battery cell according to claim 1, wherein the pressure plate further comprises a heat source.

12. A method for activating a battery cell according to claim 11, wherein the heat source is positioned by being attached to the pressure plate in the form of a heating pad or is positioned inside the pressure plate.

13. A method for activating a battery cell according to claim 12, wherein the heating pad contacts the surface of the electrode assembly housing together with the pressure plate, contacts the surface of the electrode assembly housing alone, or heats the pressure plate without contacting the surface of the electrode assembly housing.

14. A method for activating a battery cell according to claim 11, characterized in that the temperature applied to the electrode assembly housing through the heat source is 70 to 100 ℃.

15. A method for activating a battery cell according to claim 4, characterized in that air is injected while step (b) is being performed to form an air layer between the pressure plate and the surface of the electrode assembly housing.

16. A method for activating a battery cell according to claim 1, wherein the method is performed after a High Pressure Current Detector (HPCD) process performed between the pre-aging process and the degassing process, and before a Pressurized preheating (PP) process is performed.

17. A cell fixing unit for fixing a battery cell; and An activation device for a battery cell comprising a pressure plate that moves and applies pressure in the full width direction of a battery cell fixed through the cell fixing unit.

18. An activation device for a battery cell according to claim 17, characterized in that the pressure plate has a plurality of air holes formed at regular intervals in rows and columns.

19. An activation device for a battery cell according to claim 18, characterized in that the diameter of each air hole is 0.2 to 1.0 mm.

20. An activation device for a battery cell according to claim 17, wherein the pressure plate further comprises a heat source, and the heat source is positioned attached to the pressure plate in the form of a heating pad or is positioned inside the pressure plate.

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