Bag folding method and device

Abstract

A bag folding method and apparatus are disclosed. In some embodiments, a pouch folding method includes: applying heat to a wing of a battery pouch to obtain a heated wing; and folding the heating wing portion of the battery bag.

Description

[0001] Priority claims and cross-references to related applications

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2023-0102010, filed on Aug. 4, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The disclosed technology relates to a method for folding a pouch of a secondary battery. Background Art

[0004] Rechargeable secondary batteries have been widely used as power sources for wireless mobile electronic devices. In addition, secondary batteries are widely used in electric vehicles (EV) and hybrid electric vehicles (HEV) as a solution to the air pollution problem associated with conventional gasoline and diesel vehicles using fossil fuels. Summary of the invention

[0005] In some embodiments, the present technology can be implemented to provide a pouch folding method and apparatus for minimizing damage to the pouch that occurs when folding the pouch by heating and softening the wings of the battery prior to folding the wings.

[0006] In one general aspect, a pouch folding method for folding wings of a battery pouch may include an operation of heating the wings prior to the operation of folding the wings.

[0007] In the operation of heating the wing, the wing may be heated using a heater, and the heater may be installed away from the wing and heat the wing in a non-contact manner.

[0008] The heater may be an induction heater and heats the wing inductively.

[0009] In the operation of heating the wing, the heater may heat the wing while the battery is conveyed along the conveyor line.

[0010] In the operation of heating the wing, the heater may heat the wing so that the surface temperature of the wing is 220° C. or less at maximum.

[0011] The operation of folding the wing may include: a first folding operation of folding the wing 180 degrees along a first folding line; and a second folding operation of folding the 180-degree folded wing an additional 90 degrees along a second folding line. And the operation of heating the wing may include: a first heating operation of heating the wing before the first folding operation; and a second heating operation of heating the 180-degree folded wing before the second folding operation.

[0012] In the first heating operation, the wing may be heated in a non-contact manner by using the first heater, and the first heater may locally heat a sealed portion of the wing on the first folding line and a periphery thereof.

[0013] In the second heating operation, the wing portion may be heated in a non-contact manner by using a second heater, and the second heater may locally heat a sealed portion of the wing portion on the second folding line and a periphery thereof.

[0014] In another general aspect, a bag folding device for folding the wings of a battery bag may include: a conveyor line for conveying batteries; a folding unit that is installed on the conveyor line and folds the wings; and a heater that is installed on the conveyor line and heats the wings, wherein the heater is installed in front of the folding unit and heats the wings before the folding unit folds the wings.

[0015] The heater may be mounted remotely from the wing and heat the wing in a non-contact manner.

[0016] The heater may be an induction heater which induction heats the wing.

[0017] The heater may heat the wing while the battery is conveyed along the conveyor line.

[0018] The folding unit may include: a first folding unit that folds the wing 180 degrees along a first folding line; and a second folding unit that folds the wing folded 180 degrees an additional 90 degrees along a second folding line, and the heater may include: a first heater that is installed in front of the first folding unit and heats the wing; and a second heater that is installed in front of the second folding unit and heats the wing folded 180 degrees.

[0019] The first heater may heat the wing in a non-contact manner and locally heat a sealed portion of the wing on the first folding line and a periphery thereof.

[0020] The second heater may heat the wing in a non-contact manner and locally heat the sealed portion of the wing on the second folding line and the periphery thereof.

[0021] The heater may heat one end and the other end of the folding line on the wing portion, and heat the one end and the other end simultaneously.

[0022] Other features and aspects will be apparent from the following detailed description, the accompanying drawings, and the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a diagram illustrating a folded portion of a pouch type secondary battery.

[0024] Figure 2 is a diagram showing an example of a pouch type battery.

[0025] Figure 3 is a flow chart of an exemplary bag folding process.

[0026] Figure 4 (A) to Figure 4 (C) is through Figure 3 A cross-sectional view of a folded portion of a bag folded by an exemplary bag folding process is shown.

[0027] Figure 5 It is a flow chart of a bag folding method according to an embodiment of the present invention.

[0028] Figure 6 is a cross-sectional view of a folded portion of a bag folded by a folding method according to some embodiments of the present technology.

[0029] Figure 7 2 is a diagram for explaining a first folding line.

[0030] Figure 8 2 is a diagram for explaining the second folding line.

[0031] Fig. 9 is a schematic diagram of a bag folding apparatus according to some embodiments of the present technology.

[0032] Fig. 10A and Fig. 10B 2 are diagrams schematically showing heating processes performed by the heaters.

[0033] Fig. 10A is a front view of a battery according to some embodiments.

[0034] Fig. 10B is a side view of a battery according to some embodiments. DETAILED DESCRIPTION

[0035] Hereinafter, the present technology will be described with reference to the accompanying drawings.

[0036] The manufacturing process may include folding a joint portion (or sealing portion) of the outer material of the battery, for example, folding the sealing portion of the outer material toward the body of the battery. Since the area of ​​the sealing portion of the battery can be very small compared to the overall size of the battery, it may be difficult to fold the sealing portion to a desired position, and the battery may be damaged during the folding process, resulting in battery defects.

[0037] Figure 1is a diagram showing a folded portion of a pouch-type secondary battery. In this article, the pouch may be a multilayer film made of polyethylene terephthalate (PET) / nylon / aluminum (Al) / polypropylene (PP). When an external force (e.g., tension or compression) is applied to the pouch, for example, during the pouch folding process, due to the difference in stretching rates between the layers included in the pouch, delamination or interface holes may occur in the pouch, which may become a factor that reduces its quality.

[0038] In some embodiments, the disclosed technology can be implemented to provide pouch folding methods and apparatus for folding pouches that can minimize damage during the folding process by heating and softening the wings of a battery pouch prior to folding the wings.

[0039] Figure 2 2 is a diagram illustrating an example of a pouch-type battery. In some implementations, the pouch-type battery 200 may have an electrode assembly disposed in a pouch (which is an exterior material), and edges of three or four sides of the pouch are sealed.

[0040] In some implementations, the pouch battery 200 may have electrode sheets 202 arranged at one end and the other end in the longitudinal direction, respectively. In some implementations, the wing 210 is arranged at one end on the short axis where the electrode sheet 202 is not formed (the side of the pouch battery 200 on the long axis of the pouch battery 200). In one example, the wing 210 extends from the main chamber 201 where the electrode assembly is arranged and protrudes outward by a predetermined size, and the sealing portion 200S is formed by sealing the outside of the pouch.

[0041] In some implementations, in this exemplary battery structure, the wing 210 can be folded to improve the robustness of the battery and the energy density of the battery module. In some implementations, the above process can be referred to as a folding process of the battery or pouch.

[0042] Figure 3 is a flow chart of an exemplary bag folding process. The process may include folding the wings of the bag 180 degrees, pressing the wings to fix the shape of the 180-degree folded wings, further making an additional 90-degree fold (also referred to as a 270-degree fold), pressing the wings to fix the shape of the additional 90-degree folded wings, and then adhering the folded wings to the main chamber of the battery using a sizing roller.

[0043] However, as mentioned above, the bag may be a multi-layer film and thus may be directly or indirectly damaged when physically folded by external forces. Figure 2When folding along the folding line L shown, the sealed portion 200S and the unsealed portion of the bag can be folded at the same time due to the battery structure. However, due to the thickness difference between different regions and the physical properties of the polypropylene (PP) layer, the boundary between the sealed portion 200S and the unsealed portion of the bag may be most easily damaged and may become the starting point for the battery to begin to have quality abnormalities.

[0044] Figure 4 (A) to Figure 4 (C) is through Figure 3 A cross-sectional view of a folded portion of a bag folded by an exemplary bag folding process is shown. Figure 4 (A) is a cross-sectional scanning electron microscope (SEM) image of the folded portion of the bag. Figure 4 (B) is an enlarged view of the aluminum (Al) / polypropylene (PP) interface, and Figure 4 (C) is an enlarged view of the PP / Al interface. As shown in the figure, it can be seen that holes are generated at the Al / PP interface and delamination occurs at the PP / Al interface.

[0045] To address these issues, in some embodiments of the present technology, heat may be applied to the wings prior to folding them. In some embodiments, the bag folding method may include various operations described below.

[0046] Figure 5 is a flow chart of a bag folding method based on an embodiment of the present technology. In some implementations, the method may include applying heat to the wings of the bag before folding the wings.

[0047] In some embodiments, the method may include: a first heating operation (S10) to heat the wing before folding the wing 180 degrees; a 180-degree folding operation (S20) to fold the heated wing 180 degrees; a first pressing operation (S30) to press the 180-degree folded wing; a second heating operation (S40) to heat the wing before folding the 180-degree folded wing an additional 90 degrees after performing the first pressing (S30); a 90-degree folding operation (S50) to fold the heated wing an additional 90 degrees; a second pressing operation (S60) to press the folded wing through an additional 90 degrees; and a sizing operation (S70) to adhere the folded wing to the main chamber of the battery using a sizing roller.

[0048] In some embodiments of the method of the present invention, a heater may be used to heat the wing in the first heating operation (S10) or the second heating operation (S40), that is, an operation of heating the wing is performed before folding the wing. Here, the heater may be spaced apart from the wing and heat the wing in a non-contact manner.

[0049] The heater may be an induction heater, and may inductively heat the wing. Induction heating may be a method of performing electrical heating, and may be a heating method using the following principle: when current is supplied to an induction heating coil, eddy current is generated in the metal to be heated, and the temperature of the metal increases due to Joule heat generated by the resistance of the metal. The induction heater may include an electromagnet and an induction heating coil, and may be operated by a high-frequency alternating current applied to the coil.

[0050] In this way, compared with the conventional method of forming a folding line on the wing using a press, the wing can be heated in a non-contact manner using an induction heater or other types of heaters to reduce or minimize damage to the bag. In addition, the bag can be stretched by heating before folding the wing, so the above-mentioned defects of the bag can be reduced when folding the wing.

[0051] Figure 6 is a cross-sectional view of a folded portion of a bag folded by a folding method implemented according to some embodiments of the present technology. Figure 6 ,and Figure 4 Compared with the process of annealing, the holes or delamination occurring at the Al / PP interface are reduced.

[0052] Further, in some embodiments of the present technology, the method of heating the bag can be performed in a non-contact manner, so that the heating and conveying of the battery can be performed simultaneously without stopping the battery conveying. That is, in some instances, it may be necessary to stop the battery conveying in order to press the wing. On the other hand, in some embodiments of the present technology, the bag can be heated in a non-contact manner without stopping the battery conveying. Therefore, the battery manufacturing time can be reduced and the overall folding process can be improved. Moreover, the method based on some embodiments of the present technology can be easily applied to conventional bag folding equipment that has already been installed.

[0053] In the operation of heating the wing portion, that is, in each of the first heating operation (S10) and the second heating operation (S40), the wing portion may be heated so that the surface temperature of the wing portion reaches a maximum of 220° C. When the surface temperature of the bag is above 220° C., the polyethylene terephthalate (PET) layer as the outer layer of the bag may be thermally deformed. In some implementations, these problems may be solved, for example, by appropriately adjusting the output or heating time of the heater, the spacing distance between the heater and the bag, and the like.

[0054] In some implementations, in the bag, the sealed portion may have a higher rigidity than the unsealed portion. Therefore, the sealed portion can be stretched to fold smoothly. On the other hand, the unsealed portion may have a relatively low rigidity, so there is no need to stretch the unsealed portion separately. That is, in some implementations, the sealed portion of the bag is heated centrally. In some implementations of the present technology, the sealed portion and its periphery can be locally heated. The periphery can refer to a predetermined area adjacent to the sealed portion, and locally heating the sealed portion and its periphery can refer to a heating area on the heated wing having a width and length that is wider and longer than the sealed portion. In one example, the fold line on the sealed portion can be included in the heating area.

[0055] Figure 7 is a diagram for explaining the first folding line. Figure 7 , when the line where the wing is folded 180 degrees is called the first fold line L1, the first fold line can be formed (①) along the sealed portion of the wing or (②) along the unsealed portion of the wing. In this article, when the first fold line (①) is formed along the sealed portion of the wing, heating can be achieved along the entire first fold line L1. On the other hand, when the first fold line (②) is formed along the unsealed portion of the wing, the sealed portion and its periphery at the side of the short axis can be locally heated without heating the unsealed portion of the wing.

[0056] Figure 8 2 is a diagram for explaining the second folding line. Figure 8 When the line where the wing is folded an additional 90 degrees is called the second fold line L2, the second fold line L2 may be generally formed along the unsealed portion of the wing. Therefore, the sealed portion at the side of the short shaft and its periphery may be locally heated without heating the unsealed portion of the wing.

[0057] Limiting the heating area in this manner can minimize unnecessary damage, and more specifically, unnecessary damage to unsealed portions, unnecessary heating of the bag due to heating, while reducing wasted output of the heater by optimizing the heating area.

[0058] In some embodiments of the present technology, the bag folding device can be implemented as follows.

[0059] Fig. 9 Schematic diagram of a bag folding device based on some embodiments of the present technology. In some embodiments, the device may include: a conveyor line 110 for conveying batteries; a folding unit 120 installed on the conveyor line and folding the wing 210 of the bag in the battery 200; and a heater 130 installed on the conveyor line and heating the wing 210 of the bag in the battery 200.

[0060] The heater 130 may be installed in front of the folding unit 120 and heat the wing 210 before the wing 210 is folded by the folding unit 120 .

[0061] Here, the heater 130 may be installed away from the wing 210 and heat the wing 210 in a non-contact manner. As a specific embodiment, the heater 130 may be an induction heater that induction heats the wing 210.

[0062] Furthermore, the heater 130 may heat the wing portion 210 while the battery 200 is transferred along the transfer line 11 .

[0063] Reference again Fig. 9 The folding unit 120 may include a first folding unit 121 and a second folding unit 122, the first folding unit 121 folds the wing 210 180 degrees along the first folding line L1, and the second folding unit 122 folds the 180-degree folded wing 210 by an additional 90 degrees along the second folding line L2. The heater 130 may include a first heater 131 and a second heater 132, the first heater 131 is installed in front of the first folding unit 121 and heats the wing 210, and the second heater 132 is installed in front of the second folding unit 122 and heats the 180-degree folded wing 210.

[0064] The first heater 131 may heat the wing portion 210 in a non-contact manner and locally heat a sealed portion on the first folding line L1 of the wing portion 210 and the periphery thereof.

[0065] The second heater 132 may heat the wing portion 210 in a non-contact manner and locally heat a sealed portion on the second folding line L2 of the wing portion 210 and a periphery thereof.

[0066] Fig. 10A and Fig. 10B Each of them is a diagram schematically showing a heating process performed by a heater. Fig. 10A This is the front view of the battery. Fig. 10B is a side view of the battery.

[0067] As shown in the figure, the heater 130 may be installed away from the wing 210 of the battery 200 , heat the wing 210 in a non-contact manner, and locally heat the sealing portion and the periphery A thereof on the wing 210 .

[0068] Here, two or more heaters 130 may be installed, and one area A-1 and another area A-2 of the wing 210 may be heated at the same time, that is, the sealing portion located at one end of the wing 210 and its surrounding area A-1 and the sealing portion located at the other end of the wing 210 and its surrounding area A-2. Here, installing two or more heaters may mean that the heating portion of the heater is divided into two parts rather than two physically independent devices. That is, installing two or more heaters may include the case where a single heater device including two or more heating portions is installed.

[0069] Alternatively, although not shown separately in the figure, a heater 130 may be provided which heats an area of ​​the wing, i.e., a sealing portion and a surrounding area A-1 at one end of the wing 210 which the heater first encounters in the conveying direction of the battery 200, and then heats a sealing portion and a surrounding area A-2 at the other end of the wing 210 which the heater encounters next according to the conveying of the battery 200.

[0070] 10 shows the structure of the second heater 132, and the first heater 131 may also include the same structure. In addition, although not shown in the figure, the first folding line L1 may be formed along the sealing portion of the wing 210 as above. In this case, the first heater 131 may also have a long strip shape corresponding thereto and be installed parallel to the wing 210, thereby heating the entire sealing portion of the wing 210 at the same time.

[0071] As described above, in some embodiments of the present technology, before folding the wing of the battery bag, the wing can be heated to be soft, thereby reducing the bag damage caused by folding. At the same time, the wing can be heated in a non-contact manner by using an induction heater or the like, so there is no need to stop the battery transfer. Therefore, the working time and the entire process can be improved, and some embodiments of the present technology can thus be easily applied to conventional bag folding equipment.

[0072] As described above, in some embodiments of the present technology, by heating and softening the wings of a battery pouch before folding the pouch, pouch damage that occurs when the pouch is folded can be minimized.

[0073] Furthermore, in some embodiments of the present technology, the method of heating the bag is performed in a non-contact manner. Therefore, the heating can be performed while the battery is being conveyed without stopping the battery conveyance. Therefore, the battery manufacturing time can be reduced and the entire folding process can be improved, thereby allowing some embodiments of the present technology to be easily applied to conventional bag folding equipment.

[0074] The above only describes specific implementation examples of some embodiments. The disclosed embodiments and other embodiments may be changed, improved and enhanced based on the disclosure of this patent document.

Claims

1. A bag folding method, comprising: applying heat to the wings of the battery pouch to obtain heated wings; as well as The heating wings of the battery pouch are folded.

2. The method according to claim 1, wherein: Applying heat to the wing of the battery pouch includes applying heat to the wing of the battery pouch by using a heater, The heater is spaced apart from the wing and applies heat to the wing in a non-contact manner.

3. The method according to claim 2, wherein: The heater is an induction heater configured to heat the wing using induction.

4. The method according to claim 2, wherein: Applying heat to the wings of the battery pouches includes applying heat to the wings using the heater while the batteries are conveyed along a conveyor line.

5. The method according to claim 2, wherein: Applying heat to the wing of the battery pouch includes applying heat to the wing to increase a surface temperature of the wing to a maximum of 220°C.

6. The method according to claim 2, wherein: Folding the heating wing of the battery pouch comprises: A first folding operation, folding the wing portion 180 degrees along a first folding line; and A second folding operation is performed to fold the 180 degree folded wing an additional 90 degrees along a second folding line, and Wherein, applying heat to the wing portion of the battery bag comprises: a first heating operation to heat the wing portion prior to the first folding operation; and A second heating operation is performed to heat the wing portion folded 180 degrees before the second folding operation.

7. The method according to claim 6, wherein: The first heating operation comprises: applying heat to the wing portion in a non-contact manner using a first heater, The first heater locally heats the sealing portion of the wing on the first folding line and a peripheral area of ​​the sealing portion.

8. The method according to claim 6, wherein: The second heating operation comprises: by applying heat to the wing in a non-contact manner using a second heater, The second heater locally heats the sealed portion of the wing on the second folding line and a peripheral area of ​​the sealed portion.

9. A bag folding device for folding a wing of a battery bag, the device comprising: a conveyor line configured to convey the battery; a folding unit arranged on the conveying line and configured to fold the wing portion; as well as a heater disposed on the conveyor line and configured to apply heat to the wing, The heater is arranged in front of the folding unit and is configured to apply heat to the wing before the folding unit folds the wing.

10. The device according to claim 9, wherein: The heater is spaced apart from the wing and heats the wing in a non-contact manner.

11. The device according to claim 10, wherein: The heater is an induction heater that heats the wing using induction.

12. The device according to claim 10, wherein: The heater heats the wing while the battery is conveyed along the conveying line.

13. The apparatus according to claim 10, wherein: The folding unit comprises: a first folding unit configured to fold the wing portion 180 degrees along a first folding line; and a second folding unit configured to fold the 180-degree folded wing portion an additional 90 degrees along a second folding line, and The heater comprises: a first heater disposed in front of the first folding unit and configured to heat the wing portion, and A second heater is disposed in front of the second folding unit and is configured to heat the wing portion folded at 180 degrees.

14. The device according to claim 13, wherein: The first heater is configured as: applying heat to the wing in a non-contact manner; and Heat is locally applied to the sealed portion of the wing portion on the first fold line and its periphery.

15. The apparatus according to claim 13, wherein: The second heater is configured as: applying heat to the wing in a non-contact manner; and Heat is locally applied to the sealed portion of the wing portion on the second fold line and its periphery.

16. The apparatus according to claim 10, wherein: The heater heats one end and the other end of the fold line on the wing, and The one end and the other end are heated simultaneously.

Images