A method for manufacturing an electrode assembly, a battery cell manufactured using the same, and a manufacturing system for electrode assemblies.

Abstract

The present invention provides a method for manufacturing an electrode assembly and a manufacturing system for an electrode assembly that can achieve excellent bonding quality and ease of bonding between electrode tabs and lead tabs, prevent lithium burning during the bonding process between electrode tabs and lead tabs, and allow the manufacturing process to be carried out with the electrode tabs cooled and hardened to increase their mechanical rigidity. A method for manufacturing an electrode assembly is provided, comprising a preparation step of aligning the electrode tabs of one or more first electrode plates; a cooling step of cooling the electrode tabs; and a connection step of combining the cooled electrode tabs and lead tabs with each other.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an electrode assembly, a battery cell manufactured using the same, and a manufacturing system for an electrode assembly.

Background Art

[0002] Unlike primary batteries, secondary batteries can be charged and discharged, and thus can be applied to various fields such as digital cameras, mobile phones, notebook computers, hybrid vehicles, and electric vehicles. Examples of secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-hydrogen batteries, and recently, lithium-ion batteries have been widely used.

[0003] In the case of conventional lithium-ion batteries, copper, aluminum foil, etc. are used as metal current collectors on the negative electrode or the positive electrode, and a negative electrode or a positive electrode is produced by laminating a negative electrode active material or a positive electrode active material on both sides thereof.

[0004] In contrast, in the case of next-generation batteries such as lithium-sulfur batteries (Li-S batteries) and lithium-metal batteries (Li-Metal batteries), the negative electrode can be composed of lithium metal itself. In this case, since the lithium metal constituting the negative electrode plate has lower mechanical strength than the metal current collector of the conventional negative electrode, there is a risk of being easily deformed or welded during the process of manufacturing the negative electrode. In particular, the electrode tab of the negative electrode made of lithium metal is pushed out by pressure during the welding process with the lead tab, so there are problems that it does not have sufficient bonding strength or interference may occur with other components of the battery cell, and it is easily welded to the welding machine.

[0005] Therefore, there is a need for a manufacturing method that can increase the ease of bonding and the bonding strength between the electrode tab of the negative electrode made of lithium metal and the lead tab.

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention was devised to solve at least some of the problems of the prior art described above, and provides a method for manufacturing an electrode assembly and a manufacturing system for an electrode assembly that can realize excellent bonding quality and ease of bonding between electrode tabs and lead tabs.

[0007] Furthermore, an object of the present invention is to provide a method for manufacturing an electrode assembly and a manufacturing system for an electrode assembly that can prevent lithium burning during the bonding process between the electrode tab and the lead tab.

[0008] Furthermore, an object of the present invention is to provide a method for manufacturing an electrode assembly and a manufacturing system for an electrode assembly, in which the manufacturing process can be carried out while the electrode tabs are cooled and hardened, thereby increasing their mechanical rigidity. [Means for solving the problem]

[0009] To achieve the above-mentioned objectives, an embodiment provides a method for manufacturing an electrode assembly, which includes a preparation step of aligning the electrode tabs of one or more first electrode plates; a cooling step of cooling the electrode tabs; and a connection step of combining the cooled electrode tabs and lead tabs with each other.

[0010] In the method for manufacturing an electrode assembly according to the embodiment, the electrode tabs of one or more first electrode plates may be made of lithium or a lithium-containing alloy.

[0011] In one embodiment, the electrode tab can be cooled under pressure by a cooling device during the cooling stage.

[0012] In the method for manufacturing an electrode assembly according to the embodiment, the cooling device includes a first pressing section and a second pressing section that move relative to each other in a direction toward each other to pressurize the electrode tab, and at least one of the first pressing section and the second pressing section may include a cooling channel through which a refrigerant flows.

[0013] In the method for manufacturing an electrode assembly according to this embodiment, the refrigerant flowing through the cooling channel may be liquid nitrogen.

[0014] In the embodiment, during the preparation stage, one or more first electrode plates are alternately stacked with one or more second electrode plates separated by a separation film, and one or more second electrode plates may have polarity opposite to that of one or more first electrode plates.

[0015] In this embodiment, an electrode tab bundle is formed in which one or more electrode tabs of a first electrode plate are stacked during the preparation stage, and the electrode tab bundle can be cooled during the cooling stage.

[0016] In the method for manufacturing an electrode assembly according to the embodiment, one or more first electrode plates may be composed of lithium or a lithium-containing alloy.

[0017] In the embodiment, the connection steps may include a first connection step of aligning the cooled electrode tab and lead tab on a connecting device; and a second connection step in which the electrode tab and lead tab are combined by the connecting device.

[0018] In this embodiment, the temperature of the electrode tab may be 0°C or lower during the first connection stage.

[0019] In the embodiment, the electrode tab and lead tab may be joined together by ultrasonic welding in the second connection stage.

[0020] A battery cell is provided which includes an electrode assembly manufactured by a method for manufacturing an electrode assembly according to an embodiment, and a case covering the electrode assembly.

[0021] In one embodiment, a manufacturing system for an electrode assembly is provided, which includes a lamination apparatus for aligning one or more first electrode plates and one or more second electrode plates having opposite polarities; a cooling apparatus for cooling the electrode tabs of one or more first electrode plates; and a connecting apparatus for connecting the cooled electrode tabs and lead tabs.

[0022] In an embodiment, the cooling device includes a first pressing part and a second pressing part that relatively move in a direction approaching each other to press an electrode tab, and at least one of the first pressing part and the second pressing part can include a cooling flow path through which a refrigerant flows.

[0023] In an embodiment, the connecting device can be configured to ultrasonically weld a cooled electrode tab and a lead tab.

Advantages of the Invention

[0024] According to an embodiment, it is possible to implement a method for manufacturing an electrode assembly and a manufacturing system for an electrode assembly that can achieve excellent bonding quality and ease of bonding between an electrode tab and a lead tab.

[0025] Also, according to an embodiment, it is possible to provide a method for manufacturing an electrode assembly and a manufacturing system for an electrode assembly that can prevent the phenomenon of lithium sintering during the bonding process between an electrode tab and a lead tab.

[0026] Also, through a cooling process, it is possible to provide a method for manufacturing an electrode assembly and a manufacturing system for an electrode assembly in which the manufacturing process can be performed in a state where the electrode tab is cooled and hardened and its mechanical rigidity is increased.

Brief Description of the Drawings

[0027] [Figure 1] It is an exploded perspective view of a battery cell. [Figure 2] Exemplarily shows the configuration of an electrode assembly. [Figure 3] It is a flowchart showing a method for manufacturing an electrode assembly according to an embodiment. [Figure 4] Exemplarily shows an exemplary configuration of a manufacturing system for an electrode assembly according to an embodiment. [Figure 5] Exemplarily shows an exemplary configuration of a cooling device. [Figure 6] It is a reference diagram exemplarily showing a state where at least a part of an electrode tab is cooled by a cooling device. [Figure 7] Exemplarily shows an exemplary configuration of a connecting device. [Modes for carrying out the invention]

[0028] Prior to the detailed description of this application, terms and words used herein and in the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather in a manner consistent with the technical idea of ​​the invention, based on the principle that terms can be appropriately defined as concepts in order to best describe the invention. Accordingly, the embodiments described herein and the configurations illustrated in the drawings are merely the most preferred embodiments of the invention and do not represent the entire technical idea of ​​the invention, and it should be understood that, at the time of filing, there may be a variety of equivalents and variations that can be substituted therefor.

[0029] The same reference numerals or symbols in the drawings attached to this specification indicate parts or components that perform substantially the same function. For the sake of explanation and understanding, different embodiments may also be described using the same reference numerals or symbols. That is, even if multiple drawings illustrate components with the same reference numerals, not all of the drawings necessarily represent a single embodiment.

[0030] In the following descriptions, singular expressions include plural expressions unless the context clearly indicates otherwise. Terms such as “contains” or “constitutes” are intended to specify the existence of features, figures, stages, operations, components, parts, or combinations thereof described in the specification, and should be understood not to preemptively exclude the existence or possibility of adding one or more different features, figures, stages, operations, components, parts, or combinations thereof.

[0031] Furthermore, in the following explanation, terms such as upper, top, lower, bottom, side, front, and rear are used based on the direction shown in the drawing, and it should be made clear beforehand that they may be used differently if the direction of the object in question is changed.

[0032] Furthermore, in this specification and claims, terms including ordinal numbers, such as "first," "second," etc., may be used to distinguish between components. Such ordinal numbers are used to distinguish identical or similar components from one another, and the use of such ordinal numbers should not restrict the meaning of the terms. For example, components combined with such ordinal numbers should not be restricted in terms of their order of use or arrangement by the numbers. Where necessary, the ordinal numbers may be used alternately with each other.

[0033] Embodiments of the present invention will be described in detail below with reference to the attached drawings. However, the spirit of the present invention is not limited to the embodiments presented. For example, a person skilled in the art who understands the spirit of the present invention may propose other embodiments that fall within the scope of the spirit of the present invention through additions, modifications, or deletions of components, and these too would fall within the scope of the spirit of the present invention. In the drawings, the shape and size of elements, etc., may be exaggerated for clearer explanation.

[0034] First, the configuration of the battery cell 1 according to the embodiment will be described with reference to Figures 1 and 2.

[0035] Figure 1 is an exploded perspective view of battery cell 1.

[0036] Figure 2 illustrates the configuration of the electrode assembly 10.

[0037] Referring to Figure 1, the battery cell 1 according to this embodiment may include an electrode assembly 10 in which a plurality of electrode plates are stacked, a case 500 in which the electrode assembly 10 is housed, and lead tabs 400 that are electrically connected to the electrode assembly 10 and a portion of which is exposed to the outside of the case 500.

[0038] The case 500 may include an electrode housing section 501 in which the electrode assembly 10 is housed and a sealing section 502 positioned along the edge of the electrode housing section 501. The electrode housing section 501 may be formed by joining an upper case 520 and a lower case 510 vertically and have an internal space in which the electrode assembly 10 is housed. The sealing section 502 is formed by crimping or heat-sealing the edges of the upper case 520 and the lower case 510 along the edge of the electrode housing section 501, thereby preventing foreign matter and moisture from outside the case 500 from flowing into the electrode assembly 10 housed inside the electrode housing section 501.

[0039] The case 500 may be a pouch-type case made of a flexible material. For example, the case 500 may be made of an aluminum laminate sheet. However, the case 500 of the battery cell 1 according to this embodiment may also be made of a can-type (or rectangular) case or a cylindrical case made of a metal material such as aluminum, in addition to the pouch-type case described above.

[0040] Referring to Figure 2, the electrode assembly 10 may have a structure in which a large number of first electrode plates 100 and a large number of second electrode plates 200 having opposite polarities are stacked with a separation membrane 300 in between. However, what is shown in Figure 2 is only a part of the first electrode plates 100, second electrode plates 200, and separation membrane 300 included in the electrode assembly 10, and the actual electrode assembly 10 may have a much larger number of first electrode plates 100, second electrode plates 200, and separation membrane 300 than what is shown in Figure 2.

[0041] The separation membrane 300 may be configured to prevent electrical short circuits between the first electrode plate 100 and the second electrode plate 200 by interposing them, and to be impregnated with an electrolyte so that ions can pass through. The separation membrane 300 may be made of a porous polymer film or a porous nonwoven fabric, etc. However, the material of the separation membrane 300 can be any material commonly used in lithium secondary batteries, in addition to the materials mentioned above, without any particular limitations.

[0042] The first electrode plate 100 and the second electrode plate 200 may be provided with electrode tabs 120 and 220, respectively. In the following description, the electrode tab of the first electrode plate 100 is defined as the first electrode tab 120, and the electrode tab of the second electrode plate 200 is defined as the second electrode tab 220.

[0043] In the electrode assembly 10, multiple first electrode tabs 120 and second electrode tabs 220 may be provided. Multiple electrode tabs 120 and 220 can be grouped together to form an electrode tab bundle if they have the same polarity. Lead tabs 400, which act as terminals in the battery cell 1, may be combined with the electrode tab bundle, thereby electrically connecting the electrode assembly 10 and the lead tabs 400. Various welding methods, including ultrasonic welding, or physical fastening methods such as rivets may be applied to combine the electrode tab bundle and the lead tabs 400.

[0044] The lead tab 400 may be made of a conductive metallic material. For example, the lead tab 400 may be made of nickel (Ni), copper (Cu), nickel-plated copper, aluminum (Al), etc. An insulating member 410 may be placed between the lead tab 400 and the case 500. For example, the insulating member 410 may be made of a material that has both insulating and adhesive properties, and is joined to the sealing portion 502 of the case 500 while covering a portion of the lead tab 400, thereby ensuring electrical insulation between the lead tab 400 and the case 500 and preventing the sealing performance between the lead tab 400 and the sealing portion 502 from being impaired.

[0045] On the other hand, the specific structure of the electrode assembly 10 and lead tab 400 according to the embodiment is not limited to what is shown in Figures 1 and 2.

[0046] For example, unlike in Figure 2, the electrode assembly 10 may be configured such that a first electrode plate 100 is placed on one side of a single separation membrane 300 that is bent in a zigzag shape, and a second electrode plate 200 is placed on the other side.

[0047] Alternatively, unlike in Figure 2, the electrode assembly 10 may have a roll-type structure in which a first electrode plate 100 and a second electrode plate, each provided as a single sheet, are wound together with a separation membrane 300 sandwiched between them.

[0048] In this embodiment, the first electrode plate 100 and the second electrode plate 200 of the electrode assembly 10 may be electrode plates having opposite polarities. For example, if the first electrode plate 100 is a negative electrode plate, the second electrode plate 200 may be a positive electrode plate.

[0049] The positive electrode plate 200 may have a structure in which a positive electrode active material layer 230 is formed on a current collector 210. For example, the active material layer 230 on the positive electrode plate 200 may be formed by coating a mixture of positive electrode active material, conductive material, and binder onto a current collector 210 made of an aluminum alloy material. In this case, the materials for the positive electrode active material, binder, conductive material, and current collector can be any known materials used in the positive electrode plate 200 of a lithium secondary battery.

[0050] Unlike conventional negative electrode plates, the negative electrode plate 100 of the battery cell 1 according to this embodiment may be made of a lithium metal sheet.

[0051] Conventionally, a negative electrode plate may have a structure in which a negative electrode active material layer is formed on a current collector. For example, a negative electrode plate may be formed by coating a mixture of negative electrode active material, conductive material, and binder onto a current collector made of a copper alloy material.

[0052] In contrast, the negative electrode plate 100 of the battery cell 1 according to this embodiment may have an integrated structure consisting of a negative electrode body portion 110 made of a lithium metal sheet and a negative electrode tab 120 disposed on one side of the negative electrode body portion 110. The lithium metal sheet is a flat sheet member made of lithium or a lithium alloy material, and the negative electrode body portion 110 and the negative electrode tab 120 according to this embodiment can be realized by appropriately processing the shape of the lithium metal sheet.

[0053] A battery cell 1 to which a negative electrode plate 100 made of a lithium metal sheet is applied can omit conventional negative electrode current collectors made of nickel (Ni), aluminum (Al), copper (Cu), etc., which is advantageous not only for reducing the weight of the battery cell 1 but also for having a very high energy density.

[0054] However, if the negative electrode plate 100 and the negative electrode tab 120 located on one side of the negative electrode plate 100 consist only of lithium metal without a metal current collector, the low mechanical strength of lithium may cause them to easily wrinkle or break during the manufacturing process of the electrode assembly 10, potentially leading to frequent problems of lithium seizure between the manufacturing equipment and the assembly, resulting in inefficiencies in the manufacturing process.

[0055] In particular, if the electrode tab 120 of the negative electrode plate 100 is made of lithium metal, during the ultrasonic welding process that combines the electrode tab 120 and the lead tab 400, there is a risk that the electrode tab 120 may be spread apart, causing a short circuit with other components of the battery cell 1 (for example, the electrode tab 220 of the positive electrode plate 200 or the case 500), or that the lithium metal of the electrode tab 120 may stick to the welding equipment.

[0056] To solve these problems, the negative electrode plate 100 according to the embodiment can be introduced into the connection process with the lead tab 400 in a cooled and hardened state through the electrode assembly manufacturing system 600 or electrode assembly manufacturing method S300 described through Figures 3 to 7. By cooling and hardening the electrode tab 120 of the negative electrode plate 100, the mechanical strength of the electrode tab 120 is greatly increased, preventing lithium seizure problems and improving welding quality.

[0057] The manufacturing method S300 for the electrode assembly will be explained below with reference to Figure 3.

[0058] Figure 3 is a flowchart showing the method for manufacturing the electrode assembly according to the embodiment.

[0059] The electrode assembly and battery cell described in Figure 3 include all the features of the electrode assembly 10 and battery cell 1 described in Figures 1 and 2, and explanations that overlap with those in Figures 1 and 2 can be omitted.

[0060] The manufacturing method for electrode assemblies 10 in Figures 1 and 2 may include a preparation step S310 in which electrode tabs 120 and 220 in Figures 1 and 2 are aligned with electrode plates 100 and 200 in Figure 2, a cooling step S320 in which at least a portion of the aligned electrode tabs 120 and 220 are cooled, and a connection step S330 in which the cooled electrode tabs and lead tabs 400 in Figure 1 are combined with each other.

[0061] In preparation step S310, one or more first electrode plates 100 in Figure 2 and one or more second electrode plates 200 in Figure 2 can be alternately stacked with the separation membrane 300 in Figure 2 in between. For example, in preparation step S310, as shown in Figure 2 above, multiple first electrode plates 100 and second electrode plates 200 can be alternately stacked in one direction with the separation membrane 300 in between. In this case, the first electrode tabs 120 of the first electrode plate 100 can be aligned to a previously set position to form a first electrode tab bundle, and the second electrode tabs 220 of the second electrode plate 200 can be aligned to a position separated from the first electrode tab bundle to form a second electrode tab bundle.

[0062] In the cooling step S320, at least one of the first electrode tab bundle or the aligned second electrode tab bundle can be cooled using a cooling device.

[0063] The cooling device in which the cooling step S320 is performed may be configured to locally cool only the electrode tab bundle in the electrode assembly 10. For example, the cooling device may be a contact cooling type cooling device 620 as described in Figures 5 and 6 (for a detailed explanation therein, please refer to the explanation of Figures 5 and 6). Alternatively, the cooling device may have the structure of a container that contains a refrigerant in a liquid or gaseous state and is open on one side, in which case the electrode tab bundle of the electrode assembly 10 may be immersed in the refrigerant contained in the container for a predetermined time to perform the cooling action. However, the specific configuration of the cooling device is not limited to those described above, and any configuration that can locally cool the electrode tab bundle of the electrode assembly 10 may be applied without limitation.

[0064] In the cooling step S320, the target cooling temperature of the electrode tab bundle may be lower than room temperature (approximately 25°C). For example, the target cooling temperature of the electrode tab bundle may be 0°C or lower, preferably around -10°C. However, the target cooling temperature of the electrode tab bundle is not limited to the above and can be appropriately increased or decreased depending on various variables such as the size of the electrode tabs, the thickness of the electrode tab bundle, and the configuration of the connecting device that combines the lead tabs 400 and the electrode tabs.

[0065] In the cooling step S320, the electrode tab bundle is cooled, causing the electrode tabs (e.g., 120) to harden and increase in mechanical strength. In particular, if the electrode tab 120 is made of lithium or a lithium-containing alloy (hereinafter, such electrode tabs will also be referred to as "lithium electrode tabs"), the strength and hardness of the lithium electrode tab 120 can be greatly increased through the cooling step S320. This prevents the lithium electrode tab 120 from easily wrinkling or bending during the manufacturing process of the electrode assembly 10. Furthermore, in the connection step S330, described later, during the process of interconnecting the electrode tabs 120, 220 and the lead tab 400, the phenomenon of the electrode tabs 120, 220 sticking to the connection device is prevented, while allowing the lead tab 400 and the electrode tabs 120, 220 to be strongly connected.

[0066] In the connection stage S330, the electrode tabs and lead tabs 400, which were cooled in the cooling stage S320, can be combined and electrically connected to each other.

[0067] In connection step S330, various welding methods, including ultrasonic welding, or physical fastening methods such as rivets can be applied to the combination of the electrode tab bundle and the lead tab 400. For example, if the electrode tab 120 is made of lithium or a lithium-containing alloy, ultrasonic welding can be applied to the combination of the electrode tab 120 and the lead tab 400.

[0068] Ultrasonic welding refers to a welding method that welds base materials together by applying localized ultrasonic vibrations. During the ultrasonic welding process, a certain level of pressure is applied to the workpiece, i.e., the electrode tabs 120, 220, and lead tab 400. However, when the electrode tab 120 is made of lithium or a lithium-containing alloy, the soft properties of lithium make it difficult to apply ultrasonic vibrations with sufficient pressure, and the problem of lithium adhering to the welding equipment during vibration has frequently occurred.

[0069] However, the lithium electrode tab 120, after being cooled through the cooling step S320 according to the embodiment, undergoes cooling and hardening, increasing its mechanical strength, which allows for smooth ultrasonic welding. In particular, the cooling and hardening of the lithium electrode tab 120 prevents lithium seizure problems and allows for a further increase in ultrasonic output, thereby significantly increasing the bonding strength between the electrode tab and the lead tab 400.

[0070] As shown in Figure 3, the preparation stage S310, the cooling stage S320, and the connection stage S330 may be performed sequentially. In this case, the time interval between the transition of the electrode assembly 10 from the cooling stage S320 to the connection stage S330 can be short enough to maintain the cooling state of the electrode tabs. That is, in the cooling stage S320, the electrode tabs cooled to the target cooling temperature can be introduced into the connection stage S330 while maintaining their cooling state.

[0071] After the lead tabs 400 and the electrode assembly 10 are interconnected through connection step S330, the electrode assembly 10 is housed in the case 500 through a casing step (not shown). In the casing step (not shown), an additional step may be performed to seal the end of the case 500 in which the electrode assembly 10 is housed.

[0072] In the following, with reference to Figures 4 to 7, a manufacturing system 600 for an electrode assembly that can perform the manufacturing method of the electrode assembly 10 described above will be explained.

[0073] Figure 4 shows an exemplary configuration of the electrode assembly manufacturing system 600 according to the embodiment.

[0074] Figure 5 shows an exemplary configuration of the cooling device 620.

[0075] Figure 6 is a reference diagram illustrating how at least a portion of the electrode tab 120 is cooled by the cooling device 620.

[0076] Figure 7 shows an exemplary configuration of the connection device 630.

[0077] The electrode assembly manufacturing system 600 described in Figures 4 to 7 is a system for manufacturing the electrode assembly 10 described in Figures 1 and 2, and can perform the electrode assembly manufacturing method S300 described in Figure 3. Therefore, explanations that overlap with Figures 1 to 3 can be omitted.

[0078] The electrode assembly manufacturing system 600 may include a laminating device 610 for stacking and aligning a plurality of electrode plates 100, 200, a cooling device 620 for cooling at least one of the electrode tabs 120, 220 of the electrode plates 100, 200, and a connecting device 630 for connecting lead tabs 400 to the cooled electrode tabs.

[0079] The lamination apparatus 610 can alternately stack one or more first electrode plates 100 and one or more second electrode plates 200 with a separation membrane 300 in between.

[0080] In the lamination apparatus 610, when the electrode plates 100 and 200 are stacked and aligned, the first electrode tab 120 of the first electrode plate 100 can be aligned to a previously set position to form a first electrode tab bundle, and the second electrode tab 220 of the second electrode plate 200 can be aligned to a position spaced apart from the first electrode tab 120 to form a second electrode tab bundle. That is, the lamination apparatus 610 can perform the preparation step S310 described above through Figure 3.

[0081] The lamination apparatus 610 according to this embodiment can be applied to a variety of types of devices depending on the structure of the electrode assembly 10, and can be applied without limitation as long as it is an apparatus in which a first electrode plate 100 and a second electrode plate 200 having opposite polarities are alternately arranged with a separation membrane 300 in between.

[0082] The cooling device 620 can perform the cooling step S320 described above through Figure 3.

[0083] The cooling device 620 may be configured to locally cool the electrode tabs (e.g., 120) of the electrode assembly 10. Various cooling methods can be applied to the cooling device 620, such as a cooling method by contact between a cooling member and the electrode tab 120, or a method by immersing the electrode tab 120 in a coolant.

[0084] Figures 5 and 6 show one embodiment of the cooling device 620, which consists of a plurality of press sections 621 and 622 capable of pressurizing and cooling the electrode tab 120.

[0085] Referring to Figures 5 and 6, the cooling device 620 may include a first pressing section 621 and a second pressing section 622 that move relative to each other in a direction toward each other to pressurize the electrode tabs.

[0086] In the cooling stage S320, the first pressing section 621 and the second pressing section 622 may be configured to pressurize the electrode tabs. For example, when the electrode tab 120 or the electrode tab bundle TB is located on the upper surface of the first pressing section 621, the second pressing section 622 can descend to pressurize the electrode tab 120 or the electrode tab bundle TB.

[0087] Cooling channels 621a and 622a can be formed inside the first pressing section 621 and the second pressing section 622, respectively, configured to allow the refrigerant to flow. As the refrigerant circulates through the cooling channels 621a and 622a, the first pressing section 621 or the second pressing section 622 is cooled, and the electrode tab is cooled when the cooled first pressing section 621 or the second pressing section 622 comes into contact with the electrode tab 120.

[0088] The refrigerant applied to the cooling device 620 may be, for example, liquid nitrogen. However, the type of refrigerant is not limited to this; any refrigerant that can cool the electrode tab 120 to the target cooling temperature is applicable.

[0089] To increase the contact time or contact area between the first press section 621 and the second press section 622 and the refrigerant, the cooling passages 621a and 622a may be provided in a shape that is bent multiple times. However, the specific structure of the cooling passages 621a and 622a is not limited to that shown in the drawings. Furthermore, the cooling passages 621a and 622a may be placed in only one of the first press section 621 and the second press section 622.

[0090] If necessary, either the first pressing section 621 or the second pressing section 622 may be omitted. For example, with the electrode tab 120 or electrode tab bundle TB placed on a separate workbench, one pressing section can be lowered to pressurize and cool the electrode tab 120 or electrode tab bundle TB.

[0091] At least one of the first pressing section 621 and the second pressing section 622 may be provided in a size that is sufficient to locally pressurize and cool only one of the pair of electrode tab bundles provided on the electrode assembly 10.

[0092] In preparation stage S310, the electrode tab bundle TB, which is stacked and aligned in one direction, is pressurized and cooled by the cooling device 620 to maintain a densely packed state. That is, in preparation stage S310, the electrode tabs 120, which have slight gaps between them and are aligned in one direction, are pressurized and cooled by the cooling device 620, thereby forming an electrode tab bundle TB in which the electrode tabs are densely packed and cooled and hardened. This makes it easy to align the lead tab 400 and the electrode tab bundle TB in connection stage S330 after the cooling stage S320. Therefore, the cooling device 620 can also function as a kind of pre-welding device for easy welding of the lead tab 400 and the electrode tabs 120 and 220.

[0093] On the other hand, the cooling device 620 may further include a temperature sensor (not shown) capable of measuring the temperature of the electrode tab bundle TB. The temperature sensor (not shown) may be configured to sense the temperature of the electrode tab bundle TB in real time. The cooling device 620 can cool the electrode tab bundle TB through feedback control using the temperature value sensed by the temperature sensor (not shown). For example, the first pressing section 621 and the second pressing section 622 of the cooling device 620 may be configured to pressurize the electrode tab bundle TB until its temperature reaches a predetermined target cooling temperature, and then release the pressurization once the target cooling temperature is reached.

[0094] The electrode tabs 120 or electrode tab bundles TB, cooled in the cooling device 620, can then be fed into the connecting device 630 and electrically connected to the lead tabs 400.

[0095] Figure 7 shows one embodiment of the connecting device 630, which can ultrasonically weld an electrode tab bundle and a lead tab 400.

[0096] Referring to Figure 7, the connecting device 630 may include a first welding member 631 to which the lead tab 400 and the cooled electrode tab are attached, and a second welding member 632 positioned on the first welding member 631 for ultrasonic welding the lead tab 400 and the electrode tab. For example, the first welding member 631 may be an anvil, and the second welding member 632 may be a horn.

[0097] The connection device 630 can perform the connection step S330 in Figure 3 described above. The connection step S330 by the connection device 630 can be broadly composed of the following two stages.

[0098] First, a first connection step is performed in which the cooled electrode tab bundle and lead tab 400 are aligned on the connecting member. In the first connection step, the electrode tab 120 or electrode tab bundle TB and lead tab 400, cooled by the cooling device 620, can be aligned on the first welding member 631 in an overlapping state. At this time, the temperature of the electrode tab 120 aligned on the first welding member 631 may be the temperature cooled by the cooling device 620, for example, 0°C or lower.

[0099] Subsequently, in the second connection stage, ultrasonic welding is performed on the first welding member 631 and the second welding member 632 with the electrode tab 120 and lead tab 400 pressed together. For example, in the second connection stage, the second welding member 632 descends, applying pressure to the electrode tab 120 and lead tab 400 by ultrasonic vibration, thereby joining the electrode tab 120 and lead tab 400 together and electrically connecting them.

[0100] As mentioned above, the lithium electrode tab 120, after being cooled through the cooling step S320, undergoes cooling and hardening, increasing its mechanical strength, which allows ultrasonic welding to be performed smoothly by the connecting device 630. In particular, the cooling and hardening of the lithium electrode tab 120 prevents lithium seizure problems and allows for a further increase in ultrasonic output, thereby significantly increasing the bonding strength between the electrode tab and the lead tab 400.

[0101] In addition to the above description, the specific configuration of the connecting device 630, including the first welded member 631 and the second welded member 632, can be modified without limitation by applying the technical concepts related to ultrasonic welding equipment used in the manufacture of lithium-ion battery cells 1.

[0102] On the other hand, although not shown in the drawings, the electrode assembly fabrication system 600 may further include at least one of a first transfer device (not shown) for transferring the electrode assembly 10 assembled in the lamination device 610 to the cooling device 620, and a second transfer device (not shown) for transferring the electrode assembly 10 cooled in the cooling device 620 to the connecting device 630.

[0103] However, in the embodiment, at least two of the stacking device 610, cooling device 620, and connecting device 630 may be integrated, in which case the cooling device 620 and connecting device 630 may approach the electrode assembly 10 placed on the workbench without a separate transfer device to perform the cooling stage S320 and the connecting stage S330.

[0104] According to the embodiment, the electrode tab 120, which is made of lithium or a lithium-containing alloy, can be cooled and hardened to increase the mechanical rigidity of the electrode tab 120, and the connection process with the lead tab 400 can be performed.

[0105] Since the electrode tab 120 is more rigid when cooled than when uncooled, the output of the connecting device, such as an ultrasonic welding device, can be increased, thereby increasing the bonding strength between the electrode tab 120 and the lead tab 400.

[0106] Furthermore, since the cooled electrode tab 120 has superior rigidity compared to the uncooled electrode tab 120, the ease of handling and stability during the manufacturing process of the electrode assembly 10 can be increased. In particular, since the diffusion phenomenon of lithium metal can be suppressed during the bonding process between the electrode tab 120 and the lead tab 400, it is possible to prevent the lithium electrode tab from diffusing during the ultrasonic welding process and causing interference with other parts, thereby hindering the sealing performance of the case 500.

[0107] Furthermore, since the electrode tab 120, which has been cooled and hardened through the cooling process, does not easily stick to the manufacturing equipment, such as the connecting device 630, the inefficiency of the process caused by the sticking phenomenon of lithium metal can be eliminated.

[0108] Although various embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and it will be obvious to anyone with average knowledge of the art that various modifications and variations are possible as long as they do not deviate from the technical idea of ​​the present invention as described in the claims. Furthermore, some components of the above-described embodiments may be omitted, and each embodiment may be combined with others.

[0109] [Explanation of symbols] 1: Battery cell 10: Electrode assembly 100: 1st electrode plate 120: First electrode tab 200:Second electrode plate 220: Second electrode tab 300: Separation membrane 400: Lead Tab 500: Case 600: Electrode Assembly System 610: Lamination equipment 620: Cooling device 621: First Press Department 622: Second Press Department 621a, 622a: Cooling channel 630: Connection device 631: First welded member 632: Second welding member

Claims

1. A preparatory step of aligning the electrode tabs of one or more first electrode plates, A cooling step for cooling the electrode tab, A method for manufacturing an electrode assembly, comprising a connection step in which the cooled electrode tab and lead tab are combined with each other.

2. The method for manufacturing an electrode assembly according to claim 1, wherein the electrode tabs of one or more first electrode plates are made of lithium or a lithium-containing alloy.

3. The method for manufacturing an electrode assembly according to claim 1, wherein the electrode tab is cooled under pressure by a cooling device during the cooling stage.

4. The cooling device includes a first pressing section and a second pressing section that move relative to each other in a direction toward each other to pressurize the electrode tab, The method for manufacturing an electrode assembly according to claim 3, wherein at least one of the first pressing portion and the second pressing portion includes a cooling channel through which a refrigerant flows.

5. The method for manufacturing an electrode assembly according to claim 4, wherein the refrigerant flowing through the cooling channel is liquid nitrogen.

6. The method for manufacturing an electrode assembly according to claim 1, wherein in the preparation stage, one or more first electrode plates are alternately stacked with one or more second electrode plates separated by a separation membrane, and the one or more second electrode plates have polarity opposite to that of the one or more first electrode plates.

7. In the preparation stage, an electrode tab bundle is formed in which the electrode tabs of one or more first electrode plates are stacked. The method for manufacturing an electrode assembly according to claim 6, wherein the electrode tab bundle is cooled in the cooling stage.

8. The method for manufacturing an electrode assembly according to claim 6, wherein one or more first electrode plates are negative electrode plates made of lithium or a lithium-containing alloy.

9. The aforementioned connection step is A first connection step involves aligning the cooled electrode tab and the lead tab on a connecting device, A method for manufacturing an electrode assembly according to any one of claims 1 to 8, comprising a second connection step in which the electrode tab and the lead tab are combined by the connection device.

10. The method for manufacturing an electrode assembly according to claim 9, wherein the temperature of the electrode tab is 0°C or lower in the first connection stage.

11. The method for manufacturing an electrode assembly according to claim 9, wherein in the second connection stage, the electrode tab and the lead tab are joined together by ultrasonic welding.

12. An electrode assembly manufactured by the method for manufacturing an electrode assembly according to claim 1, A battery cell, including a case that covers the electrode assembly.

13. A lamination apparatus for aligning one or more first electrode plates and one or more second electrode plates having opposite polarities, A cooling device for cooling the electrode tabs of one or more first electrode plates, A manufacturing system for an electrode assembly, comprising a connecting device for connecting the cooled electrode tab and the lead tab.

14. The cooling device includes a first pressing section and a second pressing section that move relative to each other in a direction toward each other to pressurize the electrode tab, The electrode assembly manufacturing system according to claim 13, wherein at least one of the first pressing section and the second pressing section includes a cooling channel through which a refrigerant flows.

15. The electrode assembly manufacturing system according to claim 13, wherein the connecting device is configured to ultrasonically weld the cooled electrode tab and the lead tab.

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