Molding apparatus and molding method, and soft-pack battery casing manufactured thereby

Abstract

The molding apparatus according to embodiments of the present disclosure can mold a cup portion onto a flexible film. The molding apparatus may include: a mold having a molding space; a peeler for securing the flexible film from above the mold; a first punch selectively disposed in the molding space; and a pressing unit for applying pneumatic or hydraulic pressure to the flexible film, causing a portion of the flexible film to be stretched into the molding space. The first punch may include: a support surface defining an upper surface of the first punch; and a recess recessed downward from the support surface.

Description

Technical Field

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2023-0138682, filed in Korea on October 17, 2023, and Korean Patent Application No. 10-2024-0139708, filed in Korea on October 14, 2024, the disclosures of which are incorporated herein by reference.

[0003] field of technology

[0004] This disclosure relates to a molding apparatus and molding method for forming a pouch cell battery casing, and the pouch cell battery casing thus manufactured. Background Technology

[0005] Typically, rechargeable batteries include nickel-cadmium (NiCd), nickel-metal hydride (NiMH), lithium-ion (Li-ion), and lithium-ion polymer (Li-Ion) batteries. Rechargeable batteries are used not only in small products such as digital cameras, P-DVD players, MP3 players, mobile phones, PDAs, portable gaming devices, power tools, and electric bicycles, but also in large products requiring high output, such as electric vehicles or hybrid electric vehicles, and in energy storage systems that store surplus electricity or new renewable energy sources, as well as backup energy storage systems.

[0006] To manufacture a secondary battery, firstly, an electrode active material slurry is coated onto a positive electrode current collector and a negative electrode current collector to form a positive electrode and a negative electrode, respectively. The positive and negative electrodes are then stacked on both sides of a separator to form an electrode assembly of a predetermined shape. Next, the electrode assembly is housed in a battery casing, followed by electrolyte injection and sealing.

[0007] Secondary batteries are classified into pouch cells and can cells based on the material of the housing that contains the electrode components. Pouch cells house the electrode components in a pouch made of a flexible polymer material. Can cells, on the other hand, house the electrode components in a housing made of metal or plastic.

[0008] Pouch cell battery casings are typically manufactured by pressing a flexible pouch film to form a cup. Additionally, during cup formation, electrode assemblies are housed within the cup, and side sealing is performed to manufacture the secondary battery.

[0009] In press molding, stretching is performed by inserting the flexible film into a forming device such as a press machine and applying pressure to the film with a punch to stretch it. This will be described in more detail below.

[0010] Figure 1 This is a schematic diagram of a conventional molding device.

[0011] The conventional forming apparatus includes: a die 2 on which a soft film F is mounted and has a forming space 2a; a stripper 3 for securing the soft film F from above the die 2 and having an opening 3a; and a punch 4 for stretching the soft film F through the opening 3a. Furthermore, when the die 2 and the stripper 3 move upward relative to the punch 4, or when the punch 4 moves downward relative to the die 2 and the stripper 3, the punch 4 can apply pressure to the soft film F, thus stretching a portion of the soft film F into the forming space 2a to form a cup portion 110 on the soft film F.

[0012] However, conventional forming apparatuses require a predetermined gap (g) between the outer periphery of the punch 4 and the inner periphery of the forming space 2a of the mold 2 to prevent wrinkling or tearing in the soft film F due to friction during the relative movement of the punch 4 and the mold 2. Therefore, the outer peripheral surface 112 of the cup portion 110 formed on the soft film F is slightly inclined relative to the bottom surface 111 of the cup portion 110. Consequently, empty spaces not occupied by electrode components (not shown) are created in the cup portion 110, resulting in a decrease in the energy density of the secondary battery.

[0013] In addition, in conventional forming devices, stress is concentrated at the corners of the punch 4 when the punch 4 presses the soft film F. Therefore, when the cup portion 110 is deep-formed on the soft film F, the corners of the cup portion 110 are overstretched, resulting in a reduction in the remaining thickness, and cracks or pinholes occur at the corners of the cup portion 110.

[0014] [Prior Art Document] KR 10-2023-0029457 A (Published on March 3, 2023) Summary of the Invention

[0015] Technical issues

[0016] This disclosure relates to a forming apparatus and forming method that maintains a large remaining thickness at the corner while sharply forming the corner of a cup.

[0017] This disclosure also relates to providing a pouch-type battery casing manufactured by a molding apparatus or molding method.

[0018] Technical solution

[0019] The forming apparatus according to embodiments of the present disclosure can form a cup portion on a flexible film. The forming apparatus may include: a mold having a forming space; a peeler configured to hold the flexible film from above the mold; a first punch selectively positioned within the forming space; and a pressing unit configured to apply pneumatic or hydraulic pressure to the flexible film to stretch a portion of the flexible film into the forming space. The first punch may include: a support surface defining an upper surface of the first punch; and a recess recessed downward from the support surface.

[0020] The support surface can extend along the outer periphery of the first punch.

[0021] The support surface can be parallel to the upper surface of the mold.

[0022] The connecting edge between the supporting surface and the inner periphery of the recess can be formed into an arc shape.

[0023] When the first punch is placed in the forming space, the support surface can be located at the same height as the upper surface of the mold.

[0024] The forming apparatus may further include a second punch having a flat upper surface and being placed in the forming space after the first punch has disengaged from the forming space.

[0025] When the second punch is placed in the forming space, the upper surface of the second punch can be located at a lower height than the upper surface of the mold.

[0026] The peeler may have a pressing space at a location corresponding to the forming space. The pressing unit may be configured to apply air or hydraulic pressure to the flexible film through the pressing space.

[0027] The molding method according to embodiments of the present disclosure can mold a cup portion in a flexible film. The molding method may include the steps of: fixing the flexible film between a mold and a peeler; and applying pressure to the flexible film using pneumatic or hydraulic pressure to stretch a portion of the flexible film into the molding space of the mold. The step of applying pressure to the flexible film may include the steps of: placing a first punch in the molding space, the first punch including a support surface defining its upper surface and a recess recessed downward from the support surface; and applying pneumatic or hydraulic pressure to the flexible film while the first punch is placed in the molding space.

[0028] When the first punch is placed in the forming space, the support surface can be located at the same height as the upper surface of the mold.

[0029] The step of applying pressure to the flexible film may further include the following steps: disengaging the first punch from the forming space and placing the second punch, which has a flat upper surface, into the forming space; and applying air or hydraulic pressure to the flexible film while the second punch is placed in the forming space.

[0030] When the second punch is placed in the forming space, the upper surface of the second punch can be located at a lower height than the upper surface of the mold.

[0031] A pouch-type battery casing according to embodiments of the present disclosure may include a cup portion having a recessed shape; and a terrace portion located on at least a portion of the outer periphery of the cup portion. The cup portion may include: a bottom surface; a plurality of outer peripheral surfaces connecting the bottom surface and the terrace portion; and a thickness edge connecting adjacent outer peripheral surfaces among the plurality of outer peripheral surfaces. In a cross-sectional view perpendicular to the bottom surface, the radius of curvature of the bottom surface side of the thickness edge may be less than 1.4 times the radius of curvature of the thickness edge.

[0032] The radius of curvature of the bottom surface side of the thickness edge can be less than 10 mm.

[0033] The radius of curvature of the bottom surface of the thickness edge can be greater than the radius of curvature of the platform portion of the thickness edge.

[0034] Beneficial effects

[0035] According to exemplary embodiments of this disclosure, since the cup portion is formed by stretching a soft film under air or hydraulic pressure, stress concentration at the corners of the cup portion can be minimized. Therefore, in the deep forming of the cup portion, a large remaining thickness at the corners can be maintained, and cracks or pinholes at the corners can be prevented.

[0036] Furthermore, the radius of curvature of the cup's edges and corners can be minimized, and the periphery of the cup can be formed almost vertically. Therefore, the secondary battery can have a sharp appearance and its energy density can be increased.

[0037] Furthermore, the effects of this disclosure may include those that can be readily predicted by those skilled in the art based on exemplary embodiments of this disclosure. Attached Figure Description

[0038] The accompanying drawings illustrate exemplary embodiments of the present disclosure and, together with the following detailed description, are intended to provide a better understanding of the technical aspects of the present disclosure; therefore, the present disclosure should not be construed as limited to the drawings.

[0039] Figure 1 This is a schematic diagram of a conventional molding device.

[0040] Figure 2This is a schematic diagram of a molding apparatus according to an embodiment of the present disclosure.

[0041] Figure 3 yes Figure 2 The diagram shows a plan view of the mold.

[0042] Figure 4 yes Figure 2 A perspective view of the first punch shown in the image.

[0043] Figure 5 This is a flowchart of a molding method performed by a molding apparatus according to an embodiment of the present disclosure.

[0044] Figure 6a and Figure 6b This is a diagram illustrating the operation of a molding apparatus according to an embodiment of the present disclosure.

[0045] Figure 7 This is a schematic diagram of a molding apparatus according to another embodiment of the present disclosure.

[0046] Figure 8 This is a schematic diagram of a soft-pack battery casing according to an embodiment of the present disclosure.

[0047] Figure 9 When observed from the outside Figure 8 The image shows an enlarged view of the thickness edge and its surroundings.

[0048] Figure 10 It is intercepted along line A-A' Figure 9 A sectional view.

[0049] Figure 11 This is a perspective view of the first punch based on the comparative example. Detailed Implementation

[0050] In the following description, exemplary embodiments of the present disclosure will be described in full detail with reference to the accompanying drawings to enable those skilled in the art to readily implement the present disclosure. However, the present disclosure may be implemented in many different forms and is not limited to or construed as described below.

[0051] In order to clearly describe this disclosure, irrelevant or detailed descriptions of related known techniques that may unnecessarily obscure the subject of this disclosure have been omitted, and throughout the specification, the same or similar reference numerals are attached to the same or similar elements when reference numerals are attached to the elements in the various figures.

[0052] Furthermore, the terms or words used in the specification and appended claims should not be construed as limited to their general or dictionary meanings, but should be interpreted based on their meanings and concepts corresponding to the technical aspects of this disclosure, on the basis of allowing the inventors to appropriately define the terms for best description.

[0053] The accompanying drawings schematically illustrate various components of a secondary battery according to an embodiment of the present disclosure, and for ease of understanding, the dimensions of the components or the width of the lines may be enlarged.

[0054] Figure 2 This is a schematic diagram of a molding apparatus according to an embodiment of the present disclosure. Figure 3 yes Figure 2 The plan view of the mold shown in the figure, and Figure 4 yes Figure 2 A perspective view of the first punch shown in the image.

[0055] The molding apparatus according to embodiments of the present disclosure may include: a mold 10 having a molding space S1; a peeler 20 for fixing a soft film F above the mold 10; a pressing unit 30 for applying air or hydraulic pressure to the soft film F; and a first punch 40 optionally disposed in the molding space S1. The molding apparatus may further include a second punch 50 disposed in the molding space S1 after the first punch 40 disengages from the molding space S1.

[0056] The flexible film F may have a predetermined thickness (t). The flexible film F may be a laminate comprising a pair of resin layers located on the two outermost sides and a metal layer located between the pair of resin layers.

[0057] The soft film F can be installed on the upper surface of the mold 10. The mold 10 can have a forming space S1 recessed downward from the upper surface. The forming space S1 can have an open top and an open bottom. When the soft film F is installed on the upper surface of the mold 10, the soft film F can cover the forming space S1 from above. In addition, the first punch 40 and the second punch 50, as described below, can be inserted into the forming space S1 from the bottom of the mold 10.

[0058] The cross-section of the molding space S1 of the mold 10 can be generally rectangular. More specifically, the molding space S1 can have a first width W1 in a first direction and a second width W2 in a second direction perpendicular to the first direction. That is, the first direction can be parallel to the horizontal direction of the molding space S1, and the second direction can be parallel to the vertical direction of the molding space S1. In addition, the first width W1 can be the horizontal width of the molding space S1, and the second width W2 can be the vertical width of the molding space S1.

[0059] The peeler 20 can face the mold 10, and the soft film F is inserted between the peeler 20 and the mold 10. The peeler 20 can be configured to move up and down relative to the mold 10. When the peeler 20 moves upward, the soft film F can be inserted between the mold 10 and the peeler 20, and subsequently, when the peeler 20 moves downward, the soft film F can be held between the mold 10 and the peeler 20.

[0060] The peeler 20 may have a pressing space S2. The pressing space S2 may be formed at a position corresponding to the forming space S1 of the mold 10.

[0061] In this embodiment, the pressing space S2 may have a closed top and an open bottom. More specifically, the peeler 20 may include a cover 21 to cover the pressing space S2 from above. The cover 21, which is separate from and distinct from the peeler 20, may be fastened to the peeler 20, or the cover 21 may be integrally formed with the peeler 20.

[0062] As described below, the cover 21 may have a channel 21a communicating with the pressing space S2 and the pressing unit 30. However, this disclosure is not limited thereto, and the channel 21a may be formed in the peeler 20.

[0063] When the peeler 20 fixes the soft film F, the soft film F can cover the pressing space S2 from below. That is, while the soft film F is held between the mold 10 and the peeler 20, a portion of the soft film F can be located between the forming space S1 and the pressing space S2. In the following text, the portion of the soft film F located between the forming space S1 and the pressing space S2 is referred to as the target area.

[0064] The pressing unit 30 can apply air or hydraulic pressure to the soft film F through the pressing space S2. Therefore, the target area of ​​the soft film F can be stretched into the forming space S1, and the target area can be formed into a cup shape. Thus, the target area 110 is formed by... Figure 1 The cup portion is indicated by the same reference numeral "110".

[0065] Since the target area 110 of the soft film F is stretched into the molding space S1 and formed into a cup portion 110, the horizontal length of the cup portion 110 can be the same as or similar to the first width W1 of the molding space S1, and the vertical length of the cup portion 110 can be the same as or similar to the second width W2 of the molding space S1.

[0066] The pressing unit 30 is not limited to a specific structure. In this embodiment, the pressing unit 30 can apply hydraulic pressure to the target area 110. For example, the pressing unit 30 may include a hydraulic pump.

[0067] More specifically, the pressing unit 30 can control the internal pressure of the pressing space S2 by allowing gas to enter or leave the pressing space S2 through the channel 21a. Therefore, when the internal pressure of the pressing space S2 is higher than the internal pressure of the forming space S1 (e.g., atmospheric pressure), the target area 110 can be stretched into the forming space S1 by the pressure difference between the forming space S1 and the pressing space S2.

[0068] In other words, since isostatic pressure is applied to the target region 110, the thickness (t) of the target region 110 can be reduced uniformly throughout the entire region during the stretching process of the target region 110. Therefore, local stress concentrations in the target region 110 can be minimized.

[0069] On the other hand, the first punch 40 and the second punch 50 can be inserted into the forming space S1 from the bottom of the mold 10. More specifically, the first punch 40 and the second punch 50 can be selectively inserted into the forming space S1.

[0070] For example, the first punch 40 and the second punch 50 can move horizontally relative to the mold 10, and the mold 10 can move vertically relative to the first punch 40 and the second punch 50. In this case, with the first punch 40 aligned at the lower part of the forming space S1, the first punch 40 can be inserted into the forming space S1 when the mold 10 moves downward. Similarly, with the second punch 50 aligned at the lower part of the forming space S1, the second punch 50 can be inserted into the forming space S1 when the mold 10 moves downward.

[0071] However, this disclosure is not limited thereto, and the mold 10 may move horizontally relative to the first punch 40 and the second punch 50, or the first punch 40 and the second punch 50 may move vertically relative to the mold 10.

[0072] The outer periphery of each punch 40, 50 may contact or be adjacent to the inner periphery of the forming space S1 of the mold 10. This is because the soft film F does not enter between the outer periphery of the punch 40, 50 and the inner periphery of the forming space S1.

[0073] For example, such as Figure 4As shown, the first punch 40 may have a first width W1 in a first direction and a second width W2 in a second direction perpendicular to the first direction, to conform to the shape of the forming space S1 of the mold 10. The first direction may be parallel to the horizontal direction of the first punch 40, and the second direction may be parallel to the vertical direction of the first punch 40. Furthermore, the first width W1 may be the horizontal width of the first punch 40, and the second width W2 may be the vertical width of the first punch 40. However, in order to smoothly insert the first punch 40 into the forming space S1, the first width W1 of the first punch 40 may be slightly smaller than the first width W1 of the forming space S1, and the second width W2 of the first punch 40 may be slightly smaller than the second width W2 of the forming space S1. This description can also be applied to the second punch 50.

[0074] The first punch 40 may include a support surface 41 defining an upper surface of the first punch 40 and a recess 42 recessed downward from the support surface 41. The support surface 41 may be parallel to the upper surface of the mold 10. The support surface 41 may be flat.

[0075] The support surface 41 may extend along the outer periphery of the first punch 40. The support surface 41 may be disposed around the outer side of the recess 42. More specifically, the recess 42 may be formed in the central portion of the first punch 40, and the support surface 41 may be formed on the upper surface of the edge portion of the first punch 40.

[0076] When the first punch 40 is placed in the forming space S1, the support surface 41 can be located at the same height as the upper surface of the mold 10. Therefore, with the first punch 40 placed in the forming space S1, the edge of the target area 110 can contact the support surface 41, and the central part of the target area 110 can be stretched into the recess 42 (see...). Figure 6a ).

[0077] The connecting edge 43 connecting the support surface 41 and the inner periphery of the recess 42 can be formed in an arc shape. More specifically, the connecting edge 43 can have a predetermined radius of curvature. Therefore, it is possible to prevent cracks from forming in the target region 110 when the central portion of the target region 110 is stretched into the recess 42.

[0078] After the first punch 40 is disengaged from the forming space S1, the second punch 50 can be inserted into the forming space S1.

[0079] The upper surface 51 of the second punch 50 can be flat. When the second punch 50 is placed in the forming space S1, the upper surface 51 of the second punch 50 can be located at a height lower than the upper surface of the mold 10. That is, a predetermined height difference (h) can be formed between the upper surface 51 of the second punch 50 and the upper surface of the mold 10 (see...). Figure 6b ).

[0080] With the second punch 50 inserted into the forming space S1 of the mold 10, the target area 110 can be subjected to pressure generated by the pressing unit 30, and a portion of the target area 110 can contact the upper surface 51 of the second punch 50.

[0081] Figure 5 This is a flowchart of a molding method performed by a molding apparatus according to an embodiment of the present disclosure. Figure 6a and Figure 6b This is a diagram illustrating the operation of a molding apparatus according to an embodiment of the present disclosure.

[0082] The molding method according to this embodiment may include: step S10 of fixing the soft film F between the mold 10 and the peeler 20; and step S20 of applying pressure to the soft film F using air pressure or hydraulic pressure.

[0083] In step S10, when a predetermined gap is formed between the mold 10 and the peeler 20, the soft film F can be inserted between the mold 10 and the peeler 20. Subsequently, the gap can be reduced, and the soft film F can be fixed between the mold 10 and the peeler 20. In this case, the target area 110 of the soft film F can be located between the forming space S1 of the mold 10 and the pressing space S2 of the peeler 20.

[0084] In step S20, when pressure is applied to the soft film F, the pressing unit 30 can apply air pressure or hydraulic pressure to the soft film F through the pressing space S2 of the peeler 30.

[0085] In this embodiment, the pressing unit 30 can apply air pressure to the target area 110. The pressing unit 30 can apply isostatic pressure to the soft film F (more specifically, the target area 110) by increasing the internal pressure of the second space S2 via the channel 21a. Therefore, the target area 110 can be stretched into the forming space S1 and formed into a cup portion 110.

[0086] More specifically, step S20 of applying pressure to the soft film F may include step S21 of placing the first punch 40 in the forming space S1 of the mold 10; and step S22 of applying air pressure or hydraulic pressure to the soft film F while the first punch 40 is placed in the forming space S1.

[0087] Reference Figure 6a The first punch 40 can be inserted into the forming space S1 of the mold 10. The first punch 40 can be configured such that the support surface 41 is located at the same height as the upper surface of the mold 10.

[0088] The pressing unit 30 can apply air or hydraulic pressure to the soft film F through the pressing space S2 of the peeler 30. The pressure applied to the target area 110 by the pressing unit 30 can be appropriately adjusted to prevent the remaining thickness of the target area 110 from becoming excessively thin.

[0089] Through the first punch 40, a portion of the central side of the target region 110 (hereinafter referred to as the "first region") can be stretched into the recess 42, and a portion of the edge side of the target region 110 (hereinafter referred to as the "second region") can contact the support surface 41 to keep it flat. Subsequently, the first region can be formed into the bottom surface 111 of the cup portion 110 (see...). Figure 6b A portion of the second region may be formed as the outer peripheral surface 112 of the cup portion 110 (see...). Figure 6b Another part of the second region can be formed as an edge (stamping edge) connecting the outer peripheral surface 112 and the bottom surface 111. Yet another part of the second region can be formed as a corner where an adjacent pair of outer peripheral surfaces 112 and bottom surfaces 111 meet.

[0090] For convenience, the first region is indicated by “111”, which is the same reference numeral as the bottom surface of the cup portion 110, and the second region is indicated by “112”, which is the same reference numeral as the outer peripheral surface of the cup portion 110.

[0091] As described above, due to the isostatic pressure applied to the target region 110, the first region 111 can be uniformly stretched into the recess 42 to form a predetermined curved surface. The curved surface of the first region 111 can be lowest at the center and becomes higher towards the support surface 41.

[0092] Step S20, which applies pressure to the soft film F, may further include: step S23, which disengages the first punch 40 from the forming space S1 and places the second punch 50 in the forming space S1; and step S24, which applies air or hydraulic pressure to the soft film F while the second punch 50 is placed in the forming space S20.

[0093] In other words, the pressing unit 30 can apply a single press to the soft film F when the first punch 40 is placed in the forming space S1, and apply a second press to the soft film F when the second punch 50 is placed in the forming space S1.

[0094] Reference Figure 6bAfter the first punch 40 is disengaged from the forming space S1, the second punch 50 can be inserted into the forming space S1. The second punch 50 can be configured such that its flat upper surface 51 is located at a height lower than the upper surface of the mold 10. That is, a predetermined height difference (h) can be formed between the upper surface 51 of the second punch 50 and the upper surface of the mold 10. The second punch 50 can be located at a height lower than the height at which the first punch 40 is located. More specifically, the upper surface 51 of the second punch 50 can be located at a height lower than the lowest position of the first stretched region 111.

[0095] Furthermore, the pressure applied to the soft film F when the second punch 50 is placed in the forming space S1 can be higher than the pressure applied to the soft film F when the first punch 40 is placed in the forming space S1. In other words, the pressing unit 30 can apply a higher pressure when the second punch 50 is inserted into the forming space S1 than when the first punch 40 is inserted into the forming space S1.

[0096] Therefore, most of the first region 111 of the soft film F can contact the upper surface 51 of the second punch 50 to form the bottom surface of the cup portion 110, and most of the second region 112 can contact the inner periphery of the forming space S1 to form the outer peripheral surface of the cup portion 110.

[0097] The cup portion 110 is typically formed such that the remaining thickness of the bottom surface 111 is relatively large, while the remaining thickness of the edge (stamping edge) connecting the bottom surface 111 and the outer peripheral surface 112, as well as the corners where adjacent outer peripheral surfaces 112 meet the bottom surface 111, is relatively small. In other words, during the forming process of the cup portion 110, strong tension may occur at the edges and corners, leading to cracking. Therefore, there are limitations to forming the edges and corners with sharp edges and corners.

[0098] However, the cup portion 110 formed by the molding apparatus or molding method according to this disclosure may have a large residual thickness at the edges and corners, as well as sharp edges and corners.

[0099] More specifically, when the first punch 40 is placed in the forming space S1 and a pressure is applied to the soft film F (S22), a stretch can be concentrated on the first region 111, which will become the bottom surface of the cup portion 110, and the second region 112, which will become the edge and outer peripheral surface of the cup portion 110, can be completely retained by the support surface 41 of the first punch 40.

[0100] Subsequently, when a second press is applied to the soft film F while the second punch 50 is placed in the forming space S1 (S24), the unstretched second region 112 can be sufficiently stretched. Therefore, the soft film F (more specifically, the target region 110) can be stretched uniformly over the entire region, the remaining thickness of the edges and corners of the cup portion 110 can be large, and the edges and corners can be formed sharply.

[0101] Figure 6 is a schematic diagram of a molding apparatus according to another embodiment of the present disclosure.

[0102] In the following description, the same description as that of the molding apparatus described above according to the embodiments will be used, and the differences will be described.

[0103] The forming apparatus according to this embodiment may also include a flexible bag 23.

[0104] The flexible bag 23 can be positioned in the pressing space S2 of the peeler 20 (see...). Figure 2 The flexible bag 23 can contact the soft film F (more specifically, the target area 110). The flexible bag 23 can apply pressure to the target area 110 when it expands by the pressing unit 30, and the target area 110 can be stretched into the forming space S1.

[0105] The forming apparatus may include a bag body 24 connected to the flexible bag 23.

[0106] The bag body 24 can cover the internal space of the flexible bag 23. That is, the internal space of the flexible bag 23 can be defined by the flexible bag 23 and the bag body 24.

[0107] The bag body 24 can cover the pressing space S2 of the peeler 20. More specifically, the pressing space S2 of the peeler 20 according to this embodiment can have an open top. Furthermore, with the flexible bag 23 inserted into the pressing space S2, the bag body 24 can cover the pressing space S2 from above. That is, the bag body 24 can function as the cover 21 described in the foregoing embodiment (see...). Figure 2 The function of the cover 21 is not limited thereto, and the cover 21 and the bag body 24 can be provided separately.

[0108] The bag body 24 may have a channel 24a that connects the pressing unit 30 with the internal space of the flexible bag 23.

[0109] The pressing unit 30 controls the internal pressure of the flexible bag 23 by allowing fluid to enter and exit through the channel 24a. Fluid is a term that includes both liquids and gases. That is, the pressing unit 30 can apply pneumatic or hydraulic pressure to the target area 110. For example, the pressing unit 30 may include an air pump or a hydraulic pump.

[0110] Therefore, when the internal pressure of the flexible bag 23 is higher than the internal pressure of the forming space S1 (e.g., atmospheric pressure), the target area 110 can be stretched into the forming space S1 by the pressure difference between the forming space S1 and the internal space of the flexible bag 23.

[0111] In other words, when isostatic pressure is applied to the target region 110, the thickness (t) of the target region 110 can be reduced uniformly over the entire region during the stretching of the target region 110. Therefore, local stress concentrations on the target region 110 can be minimized.

[0112] Specifically, when the pressing unit 30 applies hydraulic pressure to the flexible film F using liquid, the liquid does not come into contact with the peeler 20 and the flexible film F through the flexible bag 23. Therefore, the risk of the forming device malfunctioning or misoperating due to liquid can be prevented.

[0113] Those skilled in the art will readily understand that the molding method described above according to the embodiments can be performed by a molding apparatus according to another embodiment of the present disclosure, and can form the cup portion 110 of a pouch battery casing.

[0114] Figure 8 This is a schematic diagram of a soft-pack battery casing according to an embodiment of the present disclosure.

[0115] The pouch-type battery casing 100 (hereinafter referred to as "battery casing") according to an embodiment of the present disclosure can be formed using the molding apparatus and molding method described above. The battery casing 100 may include a cup portion 110 having a recessed shape and a platform portion 120 located on at least a portion of the outer periphery of the cup portion 110. The platform portion 120 may be an unformed portion of the pouch film F where the cup portion 110 is not formed. The platform portion 120 may be connected to the top of the outer peripheral surface 112 of the cup portion 110. The cup portion 110 may be recessed from the platform portion 120 to a predetermined depth to form a space therein for accommodating an electrode assembly (not shown).

[0116] More specifically, the battery housing 100 can be formed by sealing a pair of housings 101, 102 connected to the fold 130. However, this disclosure is not limited to this, and the pair of housings 101, 102 in a separated state can be sealed together to form the battery housing 200.

[0117] Additionally, at least one of the pair of housings 101 and 102 may include a cup portion 110. For example, the first housing 101 may include a cup portion 110, while the second housing 102 may not include a cup portion 110. In this case, the first housing 101 may include a cup portion 110 and a platform portion 120, and the second housing 102 may be a flat plate. With the electrode assembly housed in the cup portion 110, the folding portion 130 can be folded so that the second housing 102 can cover the cup portion 110. Furthermore, the platform portion 120 of the first housing 101 and the edge portions of the second housing 102 may be joined together to form a sealed portion.

[0118] On the other hand, the cup portion 110 may include a bottom surface 111 and a plurality of outer peripheral surfaces 112. Each outer peripheral surface 112 may connect the bottom surface 111 to the platform portion 120. For example, the outer peripheral surface 112 may include four outer peripheral surfaces.

[0119] The bottom surface 111 may cover one surface of the electrode assembly, and the outer peripheral surface 112 may surround the outer periphery of the electrode assembly.

[0120] The cup portion 110 may include a thickness edge 113 connecting adjacent outer peripheral surfaces 112 of a plurality of outer peripheral surfaces 112. The thickness edge 113 may be formed in an arc shape. Since the outer peripheral surfaces 112 of the cup portion 110 include four outer peripheral surfaces, the thickness edge 113 may also include four thickness edges.

[0121] Figure 9 When observed from the outside Figure 8 The enlarged view of the thickness edge and its surroundings shown in the image, and Figure 10 It is intercepted along line A-A' Figure 9 A sectional view.

[0122] The thickness edge 113 may have a radius of curvature that varies depending on its position. More specifically, the thickness edge 113 may have a radius of curvature R1 on the bottom surface 111 side (hereinafter referred to as the first radius of curvature) and a radius of curvature R2 on the platform portion 120 side (hereinafter referred to as the second radius of curvature). Here, the radius of curvature of the thickness edge 113 may be defined based on a view viewed parallel to the bottom surface 111. That is, the first radius of curvature R1 and the second radius of curvature R2 may be defined based on a view viewed parallel to the bottom surface 111.

[0123] The first radius of curvature R1 can be defined at a position corresponding to the corner of the cup portion 110. The corner can be the part where a pair of adjacent outer peripheral surfaces 112 and bottom surfaces 111 meet.

[0124] The first radius of curvature R1 can be greater than the second radius of curvature R2. More specifically, the radius of curvature of the thickness edge 113 can decrease from the bottom surface 111 of the cup portion 110 to the platform portion 120.

[0125] In addition, such as Figure 10 As shown, the thickness edge 113 may have a radius of curvature R3 (hereinafter referred to as the third radius of curvature) defined based on a cross-sectional view taken perpendicular to the bottom surface 111.

[0126] The second radius of curvature R2 can be formed according to the shape of the mold 10. More specifically, the second radius of curvature R2 can be formed according to the shape of the edge connecting the upper surface of the mold 10 and the inner periphery of the molding space S1.

[0127] Conversely, the first radius of curvature R1 and the third radius of curvature R3 can be formed by air or hydraulic pressure applied by the pressing unit 30 during the molding process of the pouch film F. Therefore, the first radius of curvature R1 and the third radius of curvature R3 of the battery housing 100 according to this embodiment can be formed differently from the corresponding portions of a pouch battery housing manufactured by conventional methods.

[0128] More specifically, the first radius of curvature R1 can be less than 1.4 times the third radius of curvature R3. Alternatively, the first radius of curvature R1 can be greater than the third radius of curvature R3. That is, the first radius of curvature R1 can be between 1 and 1.4 times the third radius of curvature R3.

[0129] In addition, the first radius of curvature R1 can be less than 10 mm.

[0130] Figure 11 This is a perspective view of the first punch based on the comparative example.

[0131] With the aforementioned first punch 40 including a flat support surface 41 and a recess 42 therein (see above) Figure 4 Conversely, according to the comparative example, the first punch 40' may have a curved upper surface 41'. More specifically, the upper surface 41' of the first punch 40' may have a curved shape with a height increasing toward the center.

[0132] In the following, experimental examples will be described using each of the first punch 40' according to the comparative example and the first punch 40 according to the embodiments of this disclosure.

[0133] In this experimental example, as described above, with each of the first punches 40 and 40' placed in the forming space S1 of the mold 10, the pressing unit 30 applies a single press to the soft film F. Subsequently, the second punch 50 is placed in the forming space S1 of the mold 10, and the pressing unit 30 applies a second press to the soft film F. In this case, all factors are the same except for the first punches 40 and 40', and the final depth of the cup portion 110 is set to 3 mm.

[0134] Therefore, when using the first punch 40' according to the comparative example, the first radius of curvature R1 of the cup portion 110 is 13.122 mm, the second radius of curvature R2 is 3.524 mm, and the third radius of curvature R3 is 8.165 mm. Conversely, when using the first punch 40 according to the embodiment of this disclosure, the first radius of curvature R1 of the cup portion 110 is 9.424 mm, the second radius of curvature R2 is 3.095 mm, and the third radius of curvature R3 is 7.196 mm.

[0135] As described above, the first radius of curvature R1 of the cup portion 110 of the battery casing 100 according to the embodiments of this disclosure can be less than 1.4 times the third radius of curvature R3. That is, the condition R1 / R3>1.4 can be satisfied. In addition, the first radius of curvature R1 can be less than 10 mm.

[0136] Relatedly, when using the first punch 40' according to the comparative example, the first radius of curvature R1 is 13.122 mm, which is greater than 10 mm. In addition, R1 / R3 = (13.122 / 8.165) = 1.607, which is greater than 1.4.

[0137] Conversely, when the first punch 40 according to an embodiment of the present disclosure is used, the first radius of curvature R1 is 9.424 mm, which is less than 10 mm. In addition, R1 / R3 = (9.424 / 7.196) = 1.310, which is less than 1.4, and it can be seen that the condition is satisfied.

[0138] Therefore, it can be seen that the battery casing 100 according to the embodiments of the present disclosure is manufactured by the molding apparatus or molding method according to the embodiments of the present disclosure. Furthermore, it can be seen that the corners of the cup portion 110 are formed sharply.

[0139] The foregoing description has been provided to illustrate the technical aspects of this disclosure by way of example, and those skilled in the art to which this disclosure pertains will be able to make various modifications and changes without departing from the essential characteristics of this disclosure.

[0140] Therefore, the disclosed embodiments are provided to describe the technical aspects of this disclosure and are not intended to be limiting, and the technical scope of this disclosure is not limited to these embodiments.

[0141] The scope of protection of this disclosure should be interpreted by the appended claims, and should be interpreted as including all technical spirit within the equivalent scope within the scope of protection of this disclosure.

[0142] [Explanation of reference numerals in the attached figures]

[0143] 10: Mold; 20: Peeler

[0144] 21: Cap 23: Flexible bag

[0145] 24: Bag body; 30: Pressing unit

[0146] 40: First punch 41: Support surface

[0147] 42: Recess 43: Connecting edge

[0148] 50: Second punch 51: (The upper surface of the second punch)

[0149] 110: (Target area of ​​the soft-pack film), (Cup portion of the soft-pack battery casing)

[0150] 111: (of the soft-pack film) first region, (of the bottom surface of the soft-pack battery casing)

[0151] 112: (of the pouch film) second region, (of the outer peripheral surface of the pouch battery casing)

[0152] 113: Thickness edge

Claims

1. A forming apparatus for forming a cup portion on a flexible film, the forming apparatus comprising: A mold having a forming space; A peeler configured to secure the flexible film from above the mold; A first punch, which is selectively placed in the forming space; as well as A pressing unit, configured to apply pneumatic or hydraulic pressure to the flexible film to stretch a portion of the flexible film into the forming space. The first punch includes: A supporting surface, the supporting surface defining the upper surface of the first punch; and A recess that is recessed downward from the support surface.

2. The molding apparatus according to claim 1, wherein, The support surface extends along the outer periphery of the first punch.

3. The molding apparatus according to claim 1, wherein, The supporting surface is parallel to the upper surface of the mold.

4. The molding apparatus according to claim 1, wherein, The connecting edge between the supporting surface and the inner periphery of the recess is formed in an arc shape.

5. The molding apparatus according to claim 1, wherein, When the first punch is placed in the forming space, the supporting surface is located at the same height as the upper surface of the mold.

6. The forming apparatus according to claim 1, further comprising a second punch having a flat upper surface and being placed in the forming space after the first punch has disengaged from the forming space.

7. The molding apparatus according to claim 6, wherein, When the second punch is placed in the forming space, the upper surface of the second punch is located at a lower height than the upper surface of the mold.

8. The molding apparatus according to claim 1, in, The peeler has a pressing space at a position corresponding to the forming space, and The pressing unit is configured to apply air or hydraulic pressure to the soft film through the pressing space.

9. A molding method for molding a cup portion on a flexible film, the molding method comprising the following steps: The soft film is fixed between the mold and the peeler; as well as Pressure is applied to the flexible film using air or hydraulic pressure to stretch a portion of the flexible film into the forming space of the mold. The step of applying pressure to the soft membrane includes the following steps: A first punch is placed in the forming space, the first punch including a support surface defining its upper surface and a recess recessed downward from the support surface; and With the first punch placed in the forming space, air pressure or hydraulic pressure is applied to the soft film.

10. The molding method according to claim 9, wherein, When the first punch is placed in the forming space, the supporting surface is located at the same height as the upper surface of the mold.

11. The molding method according to claim 9, in, The step of applying pressure to the soft membrane further includes the following steps: The first punch is disengaged from the forming space, and a second punch with a flat upper surface is placed in the forming space; and With the second punch positioned in the forming space, air or hydraulic pressure is applied to the soft film.

12. The molding method according to claim 11, wherein, When the second punch is placed in the forming space, the upper surface of the second punch is located at a lower height than the upper surface of the mold.

13. A soft-pack battery casing, comprising: The cup portion has a concave shape; as well as A platform portion, said platform portion being located on at least a portion of the outer periphery of the cup portion. The cup portion includes: Bottom surface; Multiple outer peripheral surfaces, the multiple outer peripheral surfaces connecting the bottom surface and the platform portion; and Thick edges, the thick edges connecting adjacent peripheral surfaces of the plurality of peripheral surfaces, and In a cross-sectional view perpendicular to the bottom surface, the radius of curvature of the bottom surface side of the thickness edge is less than 1.4 times the radius of curvature of the thickness edge.

14. The soft-pack battery casing according to claim 13, wherein, The radius of curvature of the bottom surface side of the thickness edge is less than 10 mm.

15. The soft-pack battery casing according to claim 13, wherein, The radius of curvature of the bottom surface side of the thickness edge is greater than the radius of curvature of the platform side of the thickness edge.

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