Pouch cell and method of molding a seal member for a pouch cell

Abstract

Disclosed is a pouch-type battery cell in which, even without using a tape, by using infrared heating molding to completely fix a sealing member of the pouch-type battery cell, the full width of the pouch-type battery cell can be uniformly maintained from the upper end to the lower end, and a method for molding a sealing member of a pouch-type battery cell. The pouch-type battery cell includes: an electrode assembly housing member; and sealing members respectively located at both side ends of the electrode assembly housing member and protruding in an outward direction, wherein the sealing members include a portion that is overlapped by folding a tip end, and the overlapped portion of the sealing members forms a constant angle in the range of 80 to 90 degrees with a non-overlapped portion of the sealing members other than the overlapped portion, without the aid of an external force.

Description

Technical Field

[0001] This application claims priority based on Korean Patent Application No. 10-2021-0115787, filed on August 31, 2021, and Korean Patent Application No. 10-2022-0093598, filed on July 28, 2022, the entire contents of which are incorporated herein by reference.

[0002] This invention relates to a pouch battery cell and a method for molding a sealing member for a pouch battery cell. More specifically, it relates to a pouch battery cell in which the full width of the pouch battery cell can be uniformly maintained from top to bottom even without the use of tape by using a sealing member that is molded and completely fixed by infrared heating. It also relates to a method for molding a sealing member for a pouch battery cell. Background Technology

[0003] With the technological advancements and explosive growth in demand for mobile devices and automobiles, there has been increased research into secondary batteries with high energy density, high discharge voltage, and excellent output stability. Examples of such secondary batteries include lithium-sulfur batteries, lithium-ion batteries, and lithium-ion polymer batteries. Furthermore, these secondary batteries can be categorized by shape, such as cylindrical, rectangular, and pouch-type, with a growing interest in and demand for pouch-type battery cells. Pouch-type battery cells can be stacked in a highly integrated manner, offering high energy density per unit weight, are inexpensive, and easily deformable. Therefore, pouch-type battery cells can be manufactured in shapes and sizes suitable for various mobile devices and automobiles.

[0004] A typical pouch cell has a sealed structure, comprising an electrode assembly of anode, cathode, and separator stacked and housed within a flexible battery casing (i.e., a stacked electrode assembly or a stacked / folded electrode assembly housed within the battery casing), and the ends of the battery casing are sealed by heat sealing or similar methods. The flexible encapsulation material sheet constituting the battery casing is composed of one or more layers of resin and metal, and a sealing member is formed at the end of the flexible encapsulation material sheet to prevent the electrode assembly from falling to the outside and to protect it from external impacts. The sealing member of the battery casing is shaped to protrude to the side surface of the battery cell.

[0005] Figure 1 This is an exploded perspective view of a typical pouch cell. (Refer to...) Figure 1A typical pouch cell 10 includes an electrode assembly 30, electrode tabs 40 and 50 extending from the electrode assembly 30, electrode leads 60 and 70 soldered to the electrode tabs 40 and 50, and a battery housing 20 housing the electrode assembly 30. The electrode assembly 30 has a stacked or stacked / folded structure, with the anode and cathode sequentially stacked with a separator placed between them. Electrode tabs 40 and 50 extend from each plate of the electrode assembly 30, and electrode leads 60 and 70 are each electrically connected to a plurality of electrode tabs 40 and 50 extending from each plate. A portion of the electrode tabs 40 and 50 is exposed to the outside of the battery housing 20. Furthermore, an insulating film 80 may be attached to a portion of the upper and lower surfaces of the electrode leads 60 and 70 to increase the seal with the battery housing 20 while ensuring electrical insulation. The battery housing 20 is typically made of a laminate comprising resin, metal, or a mixture thereof, providing space to accommodate the electrode assembly 30, and is generally pouch-shaped. Figure 1 In the case of the stacked electrode assembly 30 shown, the upper part of the interior of the battery housing 20 can be spaced apart from the electrode assembly 30, so that multiple anode contacts 40 and multiple cathode contacts 50 can be coupled together to the electrode leads 60 and 70.

[0006] This type of pouch cell involves a process of housing the electrode assembly within the battery casing, injecting electrolyte, and then sealing it by heat sealing, and finally undergoing a process of vertically bending the outer peripheral surface of the battery cell or the heat-sealing component (sealing component). Figure 2 This is a schematic diagram of the sealing components for vertically bending and securing a standard pouch cell. Traditionally, this is performed as follows: Figure 2 The process shown involves vertically bending and securing the sealing components of the pouch cell.

[0007] Specifically, the sealing components of the battery cell are typically brought as close as possible to the electrode assembly housing components via the following steps: 1) The sealing components are hot-compressed using a hot press (if necessary, the sealing components are cut to an appropriate length before hot compression); 2) The tip of the hot-compressed sealing component is bent 90 degrees using a separate lifting block and support; 3) The tip of the 90-degree bent sealing component is bent again 90 degrees in the direction of the electrode assembly housing components using a separate block to fold the sealing component (a total of 180 degrees of bending, including the previous 90-degree bend); 4) The sealing components are then hot-compressed... 5) The machine heat-compresses the folded sealing component, and 6) the support is vertically positioned at each of the upper and lower ends between the folded sealing component and the electrode assembly housing component. Then, based on the electrode assembly housing component, the individual block is positioned facing the outer surface of the lower support and raised towards the upper support to bend the tip of the folded sealing component by 90 degrees (a total bend of 270 degrees, including the previous 180-degree bend). 7) The tip of the folded sealing component bent by 90 degrees is pressed laterally by the individual block. Finally, 7) the tip of the folded sealing component bent by 90 degrees is secured with tape.

[0008] Figure 3 This is a schematic diagram of the sealing components used to secure a standard pouch cell with tape. However, when... Figure 3 When the sealing component is fixed with tape as shown, the portion of the tape adhering ( Figure 3 1, 3 and 5) and non-tape adhesive parts ( Figure 3 A difference in full width is inevitable between 2 and 4).

[0009] Table 1

[0010] Unit 1 location 0.5mm Unit 2 location 1.5mm Unit 3 location 0.6mm Unit 4 location 1.9mm Unit 5 location 1.0mm

[0011] When full-width discrepancies occur (in the case described above, a difference of up to 1.4 mm in the full width of the cell) and full-width process control is not implemented, large errors in the full width result in cells not fitting into the module during assembly. Furthermore, because some cells ultimately require manual processing, process losses are unavoidable. Therefore, a technology is needed to fundamentally solve this problem (i.e., process losses caused by full-width discrepancies in the pouch cell) when bending the sealing components in the pouch cell. Summary of the Invention

[0012] [Technical Issues]

[0013] Therefore, the object of the present invention is to provide a pouch battery cell and a method for molding a sealing member for a pouch battery cell, wherein even without the use of tape, the full width of the pouch battery cell can be uniformly maintained from top to bottom by using an infrared-heated molding sealing member to completely fix the pouch battery cell.

[0014] [Technical Solution]

[0015] To achieve the above objectives, the present invention provides a pouch-type battery cell, the pouch-type battery cell comprising: an electrode assembly housing component; and a sealing component located at both ends of the electrode assembly housing component and protruding in an outward direction, wherein the sealing component includes portions overlapping by folding tips, the overlapping portions of the sealing component forming a constant angle within the range of 80 to 90 degrees with the non-overlapping portions of the sealing component other than the overlapping portions, without the aid of external force.

[0016] On one hand, the longitudinal width of the electrode assembly housing component and the sealing component disposed on both sides of the electrode assembly housing component can be uniform from one end to the other.

[0017] On the other hand, without the aid of external force, the overlapping portion of the sealing member and the non-overlapping portion of the sealing member, excluding the overlapping portion, can form a constant angle in the range of 85 to 90 degrees.

[0018] On another note, the overlapping portion of the sealing component can have a bending force of 200 to 250 g / cm at room temperature.

[0019] On the other hand, the electrode assembly housing and the sealing component can be made of a flexible sheet comprising a resin layer and a metal layer.

[0020] In another aspect, the resin layer may comprise polypropylene, and the metal layer may comprise aluminum.

[0021] Furthermore, the present invention includes a method for molding a sealing member for a pouch cell, the method comprising: step (a) folding and overlapping the tip of the sealing member toward an electrode assembly housing member, the tip of the sealing member being located on each of the two side ends of the electrode assembly housing member and projecting outward; step (b) hot-pressing the overlapping sealing member; step (c) positioning an upper support and a lower support member facing each other between the overlapping sealing member and the electrode assembly housing member in a direction perpendicular to the upper and lower end faces of the sealing member; and step (d) positioning a block based on the electrode assembly housing member facing the outer surface of the lower support member, and raising the block toward the upper support member to bend the tip of the overlapping sealing member toward the electrode assembly housing member, wherein the overlapping or bent portion of the sealing member is heated with infrared radiation during or after performing any one or more of steps (a), (b), and (d).

[0022] In one aspect, the infrared heating can be selected from near-infrared (N-IR) heating, mid-infrared (M-IR) heating, and far-infrared (F-IR) heating.

[0023] On the other hand, the infrared heating can be mid-infrared heating.

[0024] On the other hand, the infrared heating during step (d) can be performed before the block is raised toward the upper support.

[0025] In another aspect, the infrared heating can be performed for 1 to 2 seconds.

[0026] In another aspect, after the tip of the overlapping sealing member in step (d) is bent toward the electrode assembly housing member, the overlapping portion of the sealing member and the non-overlapping portion of the remaining sealing members can form a constant angle in the range of 80 to 90 degrees without the aid of external force.

[0027] On the other hand, after step (d), the method may further include applying a cooling block to the outer surface of the curved portion based on the electrode assembly housing component to compress and cool the outer surface.

[0028] On the other hand, the cooling block can press the outer surface of the curved portion for 1 to 10 seconds at a temperature below 10°C and a pressure of 0.2 to 0.7 MPa.

[0029] [Beneficial Effects]

[0030] In the method for forming a pouch cell and a sealing component according to the present invention, by using infrared heating to mold the sealing component that completely fixes the pouch cell, the full width of the pouch cell can be uniformly maintained from top to bottom even without the use of tape, and can be easily managed within a specific dimensional range. As a result, unlike conventional processes that use tape to partially fix the sealing component, manual production losses during module assembly can be reduced. Furthermore, since tape is not used as in conventional methods, it also offers the advantages of reduced manufacturing costs and excellent full-width handling capability (i.e., dispersion). Attached Figure Description

[0031] Figure 1 This is an exploded perspective view of a typical pouch cell.

[0032] Figure 2 This is a schematic diagram of the sealing components of a normal pouch cell being bent and vertically fixed.

[0033] Figure 3 This is a schematic diagram of how a sealing component is fixed with tape in a normal pouch cell.

[0034] Figure 4 This is a perspective view of a pouch-type battery cell according to the present invention.

[0035] Figure 5 This is a side sectional view of a pouch-type battery cell according to the present invention.

[0036] Figure 6 This is a process flow diagram showing sequentially aspects of molding the sealing components of a pouch cell according to an embodiment of the present invention.

[0037] Figure 7 This is a process flow diagram showing sequentially aspects of molding the sealing components of a pouch cell according to another embodiment of the present invention. Detailed Implementation

[0038] The present invention will now be described in detail with reference to the accompanying drawings.

[0039] Figure 4 This is a perspective view of a pouch-type battery cell according to the present invention. Figure 5 This is a side sectional view of a pouch-type battery cell according to the present invention. Figure 4 and 5 As shown, the pouch cell 100 according to the present invention includes an electrode assembly housing component 120 and a sealing component 140. The sealing components 140 are located at both ends of the electrode assembly housing component 120 and protrude outward. The sealing component 140 includes a portion 144 that overlaps by a folded tip 142. Without the aid of external force, the overlapping portion 144 of the sealing component 140 forms a constant angle with the non-overlapping portion 146 of the sealing component other than the overlapping portion 144 at a range of 80 to 90 degrees.

[0040] To install the pouch cell in a standardized module, the sealing components (or wings, the pouch areas sealing the sides of the cell) of the pouch cell need to be folded vertically and secured to position them as close as possible to the electrode assembly housing. This is because the full width of the pouch cell needs to be maintained evenly from top to bottom, allowing the pouch cell to be installed in the module without additional manual work.

[0041] In this regard, traditionally, sealing components for vertical bending and securing pouch cell units have been used, such as... Figure 2 and 3The method shown is to secure a curved sealing component of a pouch cell with tape. However, when tape is used in this way, a full-width difference occurs between the tape-attached and non-tape-attached portions. If this full-width difference occurs and the full-width process is not controlled, significant errors in the full width will result in cell failures during module assembly, and inevitably, process losses will occur since some cells are ultimately assembled manually. To address this problem, while attaching the tape to the entire sealing component could be considered, this increases both the material cost of the tape and processing time compared to sparse tape attachment, inevitably leading to a reduction in daily battery production.

[0042] Therefore, the applicant of this application has invented a technique for uniformly holding and fixing the full width of a pouch cell from top to bottom. The technique reduces and fixes the full width by performing a second fold in the DSF (double-sided folding) process, that is, a process of folding the sealing component twice as a cell manufacturing finishing process, through a "thermoforming method using infrared heating".

[0043] In other words, the present invention relates to a pouch battery cell in which the sealing components of the pouch battery cell are completely fixed by using an infrared heating thermoforming method, and the full width of the pouch battery cell remains uniform from top to bottom, and has the advantage of being able to be immediately set in a module without separate subsequent manual work.

[0044] The electrode assembly housing component 120 has a sealing structure at its end, which includes a sealing member 140 that is sealed by heat sealing or the like. The flexible encapsulation material sheet forming the electrode assembly housing component 120 includes a resin layer and a metal layer, and the sealing member 140 formed at the end of the electrode assembly housing component 120 serves not only to prevent the electrode assembly from detaching from the outside but also to protect the electrode assembly from external impacts. Therefore, the sealing member 140 is formed in a protruding shape on the side surface of the battery cell (or pouch cell 100) and is made of the same material as the electrode assembly housing component 120. The resin layer (or adhesive layer) forming the electrode assembly housing component 120 and the sealing member 140 may include, but is not limited to, polypropylene (PP) and aluminum.

[0045] The electrode assembly housing 120 is a place to house the electrode assembly, which includes at least one battery cell comprising an anode, a cathode, and a separator sandwiched between the anode and cathode. The construction of the electrode assembly is not particularly limited; for example, half-cells can be arranged on the top and bottom of the electrode assembly, and a general electrode assembly structure can be followed. Furthermore, the electrode assembly can be stacked or stacked / folded. Also, as... Figure 4As shown, the anode and cathode contacts can be positioned in opposite directions. However, as Figure 1 As shown, the anode and cathode contacts can be positioned together on only one side, and their positions can be set in various ways depending on the type and purpose of the battery.

[0046] The sealing member 140 includes a portion 144 where the tip 142 is folded inward and overlaps. This form is obtained through the first fold in the DSF (double-sided folding) process and is a structural feature designed to maximize the retaining force. Furthermore, through the second fold in the DSF process, the overlapping portion 144 of the sealing member 140 and the non-overlapping portion 146 of the remaining sealing member 140 form an angle without the aid of external force.

[0047] In this respect, the present invention has a particularly important feature. The overlapping portion 144 of the sealing member 140 and the non-overlapping portion 146 of the remaining sealing member 140 (i.e., the portion of the sealing member other than the overlapping portion) form a constant angle without the aid of external forces such as tape fixing, and the entire sealing member 140 extending from the upper end to the lower end of the two side surface portions of the pouch cell has this form. That is to say, the longitudinal full width of the electrode assembly housing member 120 and the sealing member 140 located at both ends of the electrode assembly housing member 120 is uniform from the upper end (or one end) to the lower end (or the other end). At this time, in the full width including the electrode assembly housing member 120 and the sealing member 140, the ratio of the shortest width to the longest width can be 95:100, preferably 97:100, more preferably 99:100.

[0048] Furthermore, the included angle (interior angle) between the overlapping portion 144 of the sealing member 140 and the non-overlapping portion 146 of the remaining sealing members 140 is in the range of 80 to 90 degrees. However, when precisely bent to 90 degrees during manufacturing, the included angle can be in the range of 85 to 90 degrees, more preferably in the range of 87 to 90 degrees.

[0049] The overlapping portion 144 of the sealing member 140 has a bending force of 200 to 250 g / cm at room temperature. This represents an approximately 2 to 2.5 times increase in bending force compared to bending the overlapping portion 144 of the sealing member 140 using a conventional heat source (approximately 80 to 100 g / cm) other than infrared heating. This is related to the material (PP, PET) of the resin layer forming the electrode assembly housing member 120 and the sealing member 140. This is attributed to the increased degree of hardening of the resin layer in the infrared heating method compared to conventional heating methods.

[0050] On the other hand, there is no particular limitation on the length of the overlapping portion 144 of the sealing member 140 and the length of the non-overlapping portion 146 of the remaining sealing member 140, and it can be seen that the length can vary depending on the size and shape of the module in which the pouch battery cell is located.

[0051] Next, a method for molding a sealing component for a pouch cell according to the present invention will be described. Figure 6 This is a process flow diagram showing sequentially aspects of molding the sealing components of a pouch cell according to an embodiment of the present invention. (Refer to...) Figure 6 A method for molding a sealing member for a pouch cell is described. The method for molding a sealing member for a pouch cell according to the invention comprises: (a) folding and overlapping the tip 142 of a sealing member 140 toward an electrode assembly housing member 120, the sealing member 140 being located on each of the two side ends of the electrode assembly housing member 120 and projecting outwards; (b) hot-pressing the overlapped sealing member 140; (c) positioning an upper support 160 and a lower support 170 facing each other in a direction perpendicular to the upper and lower end surfaces of the sealing member between the overlapped sealing member 140 and the electrode assembly housing member 120; and (d) positioning a block 180 facing the outer surface of the lower support 170 based on the electrode assembly housing member 120, and raising the block 180 toward the upper support 160 to bend the tip 142 of the overlapped sealing member 140 toward the electrode assembly housing member 120, and during or after performing any one or more of steps (a), (b), and (d), heating the overlapped or bent portion with infrared radiation.

[0052] First, step (a) is the step of folding and overlapping the tip 142 of the sealing member 140 toward the electrode assembly housing member 120 (i.e., the first fold), the sealing member 140 being located on each of the two side ends of the electrode assembly housing member 120 and protruding in an outward direction. This is a pre-process of the second fold (or second bend) in step (d). However, considering the second fold, it may be desirable to overlap the tip 142 of the sealing member 140 so that it is located at approximately halfway down the remaining unfolded sealing member 140.

[0053] On the other hand, before performing step (a) above, if necessary, such as Figure 1 and Figure 2As shown, any one or more of the following steps may be performed additionally: hot-pressing the unbent sealing member using a hot press, and bending the tip of the hot-pressed sealing member by approximately 90 degrees using a lifting block and a support. In particular, if the step of bending the tip of the unfolded sealing member by approximately 90 degrees is performed before performing step (a), in step (a), the sealing member 140 can overlap by folding it only about 90 degrees toward the electrode assembly housing member 120.

[0054] Next, step (b) involves the overlapping sealing components 140 ( Figure 6 In the hot-pressing process (not shown), considering the second fold, it is preferable to hot-press the entire sealing member 140. At this time, there are no restrictions on the apparatus for hot-pressing the overlapping sealing members 140, and a heat source can be built into each of the upper and lower portions of the overlapping sealing members 140, or a self-heating heating block can be provided to simultaneously hot-press the upper and lower portions of the overlapping sealing members 140. However, it may be desirable to use a heating block with a built-in heat source to increase heat transfer efficiency.

[0055] On the other hand, the temperature applied to the overlapping sealing components 140 by hot pressing in step (b) can be 160 to 220°C, preferably 180 to 200°C. If the temperature applied to the overlapping sealing components 140 by hot pressing is below 160°C, the subsequent folding may not be smooth. If the temperature exceeds 220°C, there is a risk that the outermost PET or nylon layer of the sealing component may peel off and the insulation resistance characteristics may deteriorate due to the hardening of the sealing layer. Furthermore, the hot pressing time can be 0.1 to 2 seconds, preferably 0.5 to 1.5 seconds, more preferably about 0.6 seconds. This is advantageous in terms of viscosity balance and can prevent peeling and hardening due to overheating, which is a side effect of IR heating.

[0056] Next, step (c) involves positioning the upper support 160 at the upper end and the lower support 170 at the lower end between the overlapping sealing member 140 and the electrode assembly housing member 120 in a direction perpendicular to the upper and lower end surfaces of the sealing member. This is to allow the block 180 to rise and fall stably in step (d) described later, and particularly to curl the tip 142 of the overlapping sealing member 140 with maximum force when the block 180 rises.

[0057] In addition, such as Figure 6As shown, the upper support 160 can have a straight shape similar to the lower support 170. However, the tip 142 of the overlapping sealing member 140 can have a constant angle (i.e., the upper support 160 can have an inclined portion that slopes upwards from the lower end toward the electrode assembly housing member 120) to allow it to bend as much as possible toward the electrode assembly housing member 120 (given the rebound phenomenon of the tip). In this case, the inner angle of the upper support 160 (i.e., based on the outward direction of the electrode assembly housing member 120) can be between 90 and 150 degrees.

[0058] Meanwhile, the upper support 160 and the lower support 170 are preferably made of materials with excellent heat resistance and strength. This is because, in step (d), the block 180 not only contacts the upper support 160 and the lower support 170, but also presses laterally toward the electrode assembly housing component 120 or the upper support 160 and the lower support 170 as the block 180 rises. Therefore, the upper support 160 and the lower support 170 can be made of stainless steel, heat-resistant ceramics, or heat-resistant polymers with excellent heat resistance and strength.

[0059] Step (d) involves positioning block 180 with its outer surface facing downward support 170 based on electrode assembly housing 120, and raising block 180 toward upper support 160 to bend the tip 142 of overlapping sealing member 140 toward electrode assembly housing member 120. Block 180 may include an internal heat source, be heated by an external heat source, or not be heated.

[0060] The pressure applied to the overlapping sealing member 140 by the block 180 can be 0.2 to 0.7 MPa, preferably 0.2 to 0.5 MPa. If the pressure applied to the overlapping sealing member 140 is less than 0.2 MPa, the sealing member may elastically recover and the tip of the sealing member may unfold due to the small force applied to the tip of the sealing member (i.e., excessive rebound). Furthermore, if the pressure applied to the sealing member 140 exceeds 0.7 MPa, cracks may occur in the sealing layer of the sealing member, which may lead to problems with insulation resistance and insulation voltage.

[0061] Furthermore, the pressing time using block 180 can be from 1 to 10 seconds, preferably from 1 to 8 seconds. If the pressing time using block 180 is less than 1 second, it is difficult to maintain the desired shape because it is difficult to ensure the minimum processing time for fixing the sealing component. If the hot pressing time using block 180 exceeds 10 seconds, it may be difficult to ensure the processing adhesion, and due to the excessive hot pressing time, it is difficult to ensure the insulation resistance and thickness.

[0062] On the other hand, as described above, a process of heating the overlapping or bent portions with infrared light is performed simultaneously with or after any of steps (a), (b), and (d). This is a process used to increase the flexibility of the sealing member 140, particularly when the sealing member molding (i.e., the second fold) is performed in step (d) to improve the fixing force. In the case of general sealing member insertion methods, since the heat is concentrated only on the PET / nylon layer and adhesive layer that serve as the surface of the bag or sealing member, the uniform heating and sealing of the PP layer is incomplete. However, according to the infrared heating of the present invention, the PP layer can be heated and then compressed in a short time.

[0063] Infrared heating can be near-infrared (N-IR), mid-infrared (M-IR), or far-infrared (F-IR) heating, and among these, mid-infrared heating may be preferred because the PP layer of the bag is heated in a short time and can be heated evenly to the interior of the bag surface.

[0064] For example, heating the sealing component using infrared light can be performed differently during or after step (a), during or after the hot pressing of the overlapping sealing component 140 (i.e., between steps (b) and (c)), at the point in time when the sealing component rises toward the upper support 160 from the positioning block 180, and at the point in time when the tip 142 of the overlapping sealing component 140 bends toward the electrode assembly housing component 120. However, as Figure 6 As shown, infrared heating 200 can preferably be performed before the tip 142 of the overlapping sealing member 140 is bent toward the electrode assembly housing member 120. In other words, it may be desirable to perform infrared heating 200 before raising the block 180 toward the upper support 160.

[0065] Even with infrared heating 200 for a very short time, the holding force of the bent sealing component can be improved. That is, the infrared heating time 200 can be 1 to 2 seconds, and more preferably as close to 1 second as possible. If the infrared heating time is less than 1 second, the flexibility of the sealing component due to infrared heating may be insufficient, resulting in incomplete bending in step (d). Furthermore, if the infrared heating time exceeds 2 seconds, excessive heat source may cause peeling on the surface of the sealing component.

[0066] The temperature for infrared heating 200°C can be set to 140 to 170°C, preferably 150 to 160°C, for the PP layer of the sealing component. (At this temperature, the surface temperature of the sealing component can be 160 to 220°C). When the temperature of the PP layer of the sealing component is below 140°C, the desired folding may not be achieved even with infrared heating. Furthermore, when the temperature of the PP layer of the sealing component exceeds 170°C, even with infrared heating, fluidity increases, and it may be difficult to ensure uniform seal thickness and insulation performance.

[0067] Figure 7 This is a process flow diagram sequentially illustrating aspects of molding the sealing components of a pouch cell according to another embodiment of the present invention. (See diagram for example.) Figure 7 As shown, in the method for molding a sealing component for a pouch cell according to the present invention, after step (d) of raising the block 180 toward the upper support 160 to bend the tip 142 of the overlapping sealing component 140 toward the electrode assembly housing component 120, if necessary, a step of applying a cooling block 220 to the outer surface of the bent portion based on the electrode assembly housing component to press and cool the outer surface may also be included.

[0068] Cooling block 220 is a device that can further enhance the retaining force of the sealing component bent by infrared heating, and may include an internal cooling source or be cooled by an external cooling source. The temperature of cooling block 220 can be 10°C or lower. If the temperature of cooling block 220 exceeds 10°C, there may be no advantage in using cooling block 220 because the cooling performance is difficult to predict.

[0069] Furthermore, the pressure applied to the overlapping sealing components by the cooling block 220 can be 0.2 to 0.7 MPa, preferably 0.2 to 0.5 MPa. Additionally, the pressing time using the cooling block 220 can be 1 to 10 seconds, preferably 1 to 8 seconds. If the pressing time using the cooling block 220 is less than 1 second, there may be no advantage in using the cooling block 220, and if it exceeds 10 seconds, the insulation resistance characteristics may deteriorate.

[0070] On the other hand, although the sealing component (i.e., the main sealing component) located on one side of the pouch cell has only been described above with reference to the accompanying drawings, the sealing component located on the other side can also be molded into the same shape using the same process. Although the pouch cell according to the invention and the method for molding the sealing component have been described above with reference to specific examples, the invention is not limited thereto, and it is obvious that various modifications can be made within the scope of the technical concept of the invention. Furthermore, for the sake of clear understanding of the invention, the above examples are compared with comparative examples that deviate from the scope of the invention.

[0071] [Example 1] Manufacturing of pouch cell with uniform full width

[0072] First, after fabricating a pouch cell including an electrode assembly (where multiple unit cells include stacked anodes, cathodes, and separators), sealing members located at both ends of the pouch cell are cut to appropriate lengths. The remaining sealing members are then hot-pressed using a hot press, and the tips of the hot-pressed sealing members are bent 90 degrees using separate risers and supports. Subsequently, after bending the tips of the 90-degree bent sealing members toward the electrode assembly housing and overlapping the sealing members, the overlapping sealing members are hot-pressed. Then, upper and lower supports are positioned at each of the upper and lower ends between the overlapping sealing members and the electrode assembly holding members. Subsequently, after positioning the risers facing the outer surface of the lower support based on the electrode assembly housing, the sealing members are irradiated with mid-infrared radiation (M-IR, Philips) at 180°C for 1 second and heated. Finally, the risers are raised toward the upper support, the tips of the overlapping sealing members are bent toward the electrode assembly housing, and the overlapping sealing members bent toward the electrode assembly housing are vertically fixed based on the side cross-section of the cell.

[0073] [Example 2] Manufacturing of a pouch cell with uniform full width

[0074] The sealing component of the pouch cell is molded in the same manner as in Example 1 above, except that after the cooling block, which is cooled to 7°C, faces the electrode assembly housing component outward based on the vertically bent sealing component and the cell side cross-section, the sealing component is pressed against the electrode assembly housing component for 3 seconds.

[0075] [Comparative Example 1] Manufacturing of Pocket Battery Cells

[0076] The sealing component of the pouch cell is molded in the same manner as in Example 1, except that the sealing component does not use mid-infrared radiation.

[0077] [Comparative Example 2] Manufacturing of Pocket Battery Cells

[0078] The sealing component of the pouch cell is molded in the same manner as in Example 1, except that heat is supplied to the sealing component for 1.5 seconds by a heating element having a common heat source at a temperature of 180°C, instead of radiating the sealing component with mid-infrared radiation.

[0079] [Test Example 1] Full-width processing capability (dispersion) evaluation

[0080] For each pouch cell in Examples 1 and 2 and Comparative Example 1 where the sealing component is molded, a total of 7 locations (based on a normal pouch cell where the sealing component is adhered with tape, including the tape portion, the non-tape portion, and 7 locations at both ends of the cell where the full width varies greatly) were measured to evaluate the full width handling capability (i.e., dispersion) (a total of 5 cell measurements).

[0081] As an evaluation result, the pouch cell of Example 1, in which the sealing component is vertically bent by infrared radiation, has a full-width standard deviation of approximately 0.40 mm, while the pouch cell of Example 2, which is pressed by a cooling block, has a full-width standard deviation of only approximately 0.38 mm. On the other hand, the pouch cell of Comparative Example 1, which does not use either infrared radiation or a cooling block, has a full-width standard deviation of approximately 0.83 mm, which is more than twice the standard deviation of Examples 1 and 2. Therefore, since the pouch cells of Examples 1 and 2 have a dispersion closer to the average value than the pouch cell of Comparative Example 1, it can be understood that the former have excellent full-width quality, a lower defect rate, and simpler management, and are therefore superior in terms of processing capability.

[0082] [Test Example 2] Evaluation of the bending force of the sealing component

[0083] For each pouch cell manufactured in Example 1 and Comparative Example 2, the bending force of the overlapping portion of the sealing component was measured. Measurements were performed using a UTM (model name: HD-B609B-S), and the degree of bending was observed by applying the same external force to the overlapping portion of the sealing component at room temperature.

[0084] As a result of measuring the bending force of the overlapping portion of the sealing member in each pouch cell as described above, it was found that in the pouch cell of Example 1, where the sealing member was bent by radiating infrared light, the overlapping portion of the sealing member exhibited a bending force of approximately 232 g / cm. On the other hand, in the pouch cell of Comparative Example 2, where the sealing member was bent by a heating element equipped with a general heat source, the overlapping portion of the sealing member exhibited a bending force of approximately 93 g / cm, and it was easy to bend even with a weaker force and difficult to maintain verticality.

[0085] [Symbol Explanation]

[0086] 100: Pocket battery unit

[0087] 120: Electrode assembly housing component

[0088] 140: Sealing component

[0089] 160: Upper support component

[0090] 170: Lower support component

[0091] 180: blocks

[0092] 200: Infrared heating

[0093] 220: Cooling block

Claims

1. A method for molding a sealing component for a pouch cell, the method comprising: Step (a) involves folding and overlapping the tip of the sealing member toward the electrode assembly housing member, the tip of the sealing member being positioned on each of the two ends of the electrode assembly housing member and protruding in an outward direction; Step (b): Hot-press the overlapping sealing components; Step (c) Position the upper support and the lower support so that they face each other in a direction perpendicular to the upper and lower end faces of the sealing member between the overlapping sealing member and the electrode assembly housing member. as well as Step (d) involves positioning the block facing the outer surface of the lower support based on the electrode assembly housing component, and raising the block toward the upper support component so that the tip of the overlapping sealing component bends toward the electrode assembly housing component. During or after performing any one or more of steps (a), (b), and (d), the overlapping or curved portions of the sealing component are heated with infrared radiation.

2. The method for molding a sealing component for a pouch cell according to claim 1, The infrared heating is selected from near-infrared (N-IR) heating, mid-infrared (M-IR) heating, and far-infrared (F-IR) heating.

3. The method for molding a sealing component for a pouch cell according to claim 1, The infrared heating mentioned above is mid-infrared heating.

4. The method for molding a sealing component for a pouch cell according to claim 1, The infrared heating is performed during step (d) before the block is raised toward the upper support.

5. The method for molding a sealing component for a pouch cell according to claim 1, The infrared heating process lasts for 1 to 2 seconds.

6. The method for molding a sealing component for a pouch cell according to claim 1, in, After the tip of the overlapping sealing member in step (d) is bent toward the electrode assembly housing member, the overlapping portion of the sealing member forms a constant angle with the non-overlapping portion of the remaining sealing members in the range of 80 to 90 degrees without the aid of external force.

7. The method for molding a sealing component for a pouch cell according to claim 1, further comprising: Following step (d), a cooling block is applied to the outer surface of the curved portion based on the electrode assembly housing component to compress and cool the outer surface.

8. The method for molding a sealing component for a pouch cell according to claim 7, in, The cooling block is pressed against the outer surface of the curved portion for 1 to 10 seconds at a temperature below 10°C and a pressure of 0.2 to 0.7 MPa.

9. A pouch cell manufactured by the method for molding a sealing component of a pouch cell according to claim 1, comprising: Electrode assembly housing components; as well as Sealing components are located at both ends of the electrode assembly housing component and protrude outwards. The sealing component includes portions that overlap via folded tips, and without the aid of external force, the overlapping portions of the sealing component form a constant angle within the range of 80 to 90 degrees with the non-overlapping portions of the sealing component, excluding the overlapping portions. The overlapping portion of the sealing component has a bending force of 200 to 250 g / cm at room temperature.

10. The pouch-type battery cell according to claim 9, in, The longitudinal width of the electrode assembly housing component and the sealing component disposed on both ends of the electrode assembly housing component is uniform from one end to the other.

11. The pouch-type battery cell according to claim 9, in, Without the aid of external force, the overlapping portion of the sealing component and the non-overlapping portion of the sealing component, excluding the overlapping portion, form a constant angle within the range of 85 to 90 degrees.

12. The pouch-type battery unit according to claim 9, in, The electrode assembly housing and the sealing component are made of a flexible sheet comprising a resin layer and a metal layer.

13. The pouch-type battery cell according to claim 12, The resin layer comprises polypropylene, and the metal layer comprises aluminum.

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