Method and apparatus for manufacturing pouch-type secondary battery

Abstract

A method of manufacturing a pouch-type secondary battery according to an embodiment of the present application can include a first sealing operation of fusing a lead film of an electrode lead attached to an electrode assembly to a sealing portion of a pouch in which the electrode assembly is accommodated, and a second sealing operation of sealing the sealing portion of the pouch, wherein the first sealing operation includes a heating process of irradiating a region present in the sealing portion of the pouch and corresponding to the lead film with a laser beam, thereby heating the lead film and fusing a resin layer of the region, and a bonding process of compressing the region, thereby bonding the lead film and the fused resin layer.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2020-0156017, filed on November 19, 2020, which is incorporated herein by reference in its entirety. Technical Field

[0003] This invention relates to a method and apparatus for manufacturing secondary batteries, and more specifically, to a method and apparatus for manufacturing pouch-type secondary batteries. Background Technology

[0004] Recently, due to the depletion of fossil fuels and the continuous rise in energy prices, concerns about environmental pollution have been increasing, and the demand for eco-friendly alternative energy sources has become an indispensable factor in future life. Therefore, research into technologies for generating various types of electricity, such as solar, wind, and tidal power, is ongoing, and energy storage devices such as batteries for more efficient use of the generated electricity are also receiving considerable attention.

[0005] Furthermore, with technological advancements and the increasing demand for battery-powered electronic mobile devices and electric vehicles, the demand for batteries as an energy source is also rapidly increasing. Therefore, extensive research is underway on batteries capable of meeting these diverse needs.

[0006] In particular, there is a high demand for lithium secondary batteries, such as lithium-ion batteries and lithium-ion polymer batteries, which have advantages such as high energy density, high discharge voltage and output stability.

[0007] Based on the shape of the battery casing, secondary batteries can be divided into cylindrical or prismatic batteries with electrode components built into cylindrical or prismatic metal cans, and pouch batteries with electrode components built into pouches made of aluminum laminates.

[0008] Figure 1 This is a perspective view illustrating an example of a pouch-type secondary battery.

[0009] Reference Figure 1 The pouch-type secondary battery 10 may include an electrode assembly 30 in which multiple electrodes and separators are alternately stacked, and a pouch 20 for housing the electrode assembly 30. The electrode assembly 30 may be provided with multiple tabs 31 extending from the multiple electrodes and fused to each other, and electrode leads 32 coupled to the fused tabs 31. The electrode leads 32 may protrude outward from the pouch 20 and can be easily electrically connected to a power supply target (e.g., a motor, etc.).

[0010] The bag 20 may include: a bag body 21 having a receiving portion 23 with a recessed shape to which the electrode assembly 30 is mounted; and a bag cap 22, which is attached to the bag body 21 to seal the receiving portion 23. The bag body 21 and the bag cap 22 may be integrally connected or detachable from each other before receiving the electrode assembly 30. Furthermore, a secondary receiving portion (not shown) with a recessed shape corresponding to the receiving portion 23 may be formed in the bag cap 22.

[0011] Furthermore, the bag body 21 may include a facing surface 24 located outside the receiving portion 23 and facing the bag cap 22, and at least a portion of the facing surface 24 may be thermally bonded to the bag cap 22. That is, when at least a portion of the facing surface 24 is bonded to the bag cap 22, the sealing portion of the bag 20 can be sealed.

[0012] The lead film 40 can be attached to each of the two surfaces of the electrode lead 32, thereby preventing short circuits in the electrode lead 32 while sealing the sealing portion of the bag 20, and ensuring a seal between the electrode lead 32 and the bag 20. Therefore, compared to other areas, the area present in the sealing portion of the bag 20 and adjacent to the lead film 40 can have a complex shape and different thicknesses. Consequently, in the manufacturing method according to related art, in which the sealing portion of the bag 20 is compressed and sealed by a heating strip, it is difficult to ensure uniform sealing quality, and the sealing time is prolonged.

[0013] Furthermore, the manufacturing method according to related technologies includes heating the electrode leads 32 before sealing the sealing portion of the bag 20. This is to prevent the heat from the heating strip sealing the sealing portion of the bag 20 from being conducted to the cold electrode leads 32. However, for the reasons mentioned above, a separate lead heater is required, thus increasing the cost of the manufacturing equipment and complicating temperature control.

[0014] Patent document KR 10-2012-0056316A (published on June 4, 2012) can be cited as prior art document. Summary of the Invention

[0015] Technical issues

[0016] To address the aforementioned problems, the present invention aims to provide a method and apparatus for manufacturing pouch-type secondary batteries that can reduce sealing time and improve sealing quality.

[0017] Technical solution

[0018] The method for manufacturing a pouch-type secondary battery according to the present invention includes: a first sealing operation, wherein a lead film attached to an electrode lead of an electrode assembly is fused to a sealing portion of a pouch containing the electrode assembly; and a second sealing operation, wherein the sealing portion of the pouch is sealed.

[0019] More specifically, a method for manufacturing a pouch-type secondary battery according to an embodiment of the present invention may include: a first sealing operation, wherein a lead film attached to an electrode assembly is fused to a sealing portion of a pouch containing the electrode assembly; and a second sealing operation, wherein the sealing portion of the pouch is sealed. The first sealing operation may include: a heating step, wherein a region present in the sealing portion of the pouch and corresponding to the lead film is irradiated with a laser beam, thereby heating the lead film and melting a resin layer in the region; and a bonding step, wherein the region is compressed, thereby bonding the lead film and the molten resin layer together.

[0020] The first sealing operation and the second sealing operation can be performed sequentially.

[0021] The area sealed in the first sealing operation may be included in the sealing portion sealed in the second sealing operation.

[0022] The length of the region relative to the width of the lead film may be greater than or equal to the width of the lead film.

[0023] The heating process and the bonding process can be performed simultaneously.

[0024] The laser beam can be an infrared laser beam with a wavelength of 808nm to 980nm.

[0025] The laser unit performing the first sealing operation may include: a light source configured to emit a laser beam; and a compression section that compresses the area present in the sealing section of the bag and corresponding to the lead film, the compression section having a transparent or translucent material that transmits the laser beam.

[0026] The light source can emit a laser beam while the region is compressed by the compression section.

[0027] The sealing tool may include a heating strip that compresses the sealing portion. The temperature of the compression portion when compressing the area may be lower than the temperature of the heating strip when compressing the sealing portion.

[0028] The area sealed in the first sealing operation can be excluded from the sealing portion sealed in the second sealing operation.

[0029] An apparatus for manufacturing a pouch-type secondary battery according to an embodiment of the present invention may include: a laser unit configured to fuse a lead film of an electrode lead attached to an electrode assembly to a sealing portion of a pouch containing the electrode assembly; and a sealing tool configured to seal the sealing portion of the pouch after the lead film has been fused to the sealing portion, wherein the laser unit includes: a light source configured to emit a laser beam; and a compression portion configured to compress a region present in the sealing portion of the pouch and corresponding to the lead film, the compression portion having a transparent or translucent material that transmits the laser beam.

[0030] The device may further include an optical section configured to guide a laser beam emitted from the light source to the compression section.

[0031] The compression section may be made of quartz material.

[0032] The compression section can refract or reflect the laser beam emitted from the light source.

[0033] Beneficial effects

[0034] According to a preferred embodiment of the invention, a first sealing operation can be provided, wherein a laser beam is used to irradiate and compress the area present in the sealing portion of the bag and corresponding to the lead film. Therefore, compared to sealing methods according to related art, the sealing quality in the area near the lead film, which has a complex shape, can be improved, and the sealing time can be reduced.

[0035] Furthermore, only the aforementioned area is illuminated by the laser beam. Therefore, the laser unit has a compact size and reduces equipment costs.

[0036] Furthermore, the irradiation time and intensity of the laser beam can be adjusted. Therefore, a separate lead heater for preheating the electrode leads is not required.

[0037] Furthermore, when the second sealing operation seals the area including the aforementioned region, the seal in that region is further strengthened.

[0038] Furthermore, when the second sealing operation seals areas other than the aforementioned area, the sealing quality of those areas is maintained at a high level.

[0039] Furthermore, the length of this region relative to the width of the lead film can be greater than or equal to the width of the lead film. Therefore, the lead film can be reliably thermally fused to the sealing portion.

[0040] Furthermore, the heating and bonding processes of the first sealing operation can be performed simultaneously. Therefore, the molten resin in the heating process can be reliably thermally fused to the lead film.

[0041] Furthermore, the compression section of the laser unit can compress this region and also allow the laser beam to be transmitted through it. Additionally, the compression section itself can function as an optical component. Therefore, the structure of the laser unit becomes simple and compact.

[0042] Furthermore, the compression section may include a quartz material. Therefore, the compression section can sufficiently and firmly compress the region while allowing the laser beam to pass through it. Attached Figure Description

[0043] Figure 1 This is a perspective view illustrating an example of a pouch-type secondary battery.

[0044] Figure 2 This is a plan view of a pouch-type secondary battery formed by the method of manufacturing a pouch-type secondary battery according to the present invention.

[0045] Figure 3 This is a flowchart illustrating a method for manufacturing a pouch-type secondary battery according to an embodiment of the present invention.

[0046] Figure 4 This is a schematic diagram illustrating an example of a laser unit used to perform the first sealing operation.

[0047] Figure 5 This is a schematic diagram illustrating another example of a laser unit used to perform the first sealing operation.

[0048] Figure 6 This is a schematic diagram illustrating a sealing tool used to perform the second sealing operation.

[0049] Figure 7 This is a flowchart illustrating a method for manufacturing a pouch-type secondary battery according to another embodiment of the present invention. Detailed Implementation

[0050] Preferred embodiments of the invention will be described in detail below with reference to the accompanying drawings to facilitate implementation by those skilled in the art. However, the invention can be implemented in various different forms and is not limited to or restricted by the following embodiments.

[0051] To clearly describe the invention, irrelevant parts have been omitted, and descriptions related to well-known functions or configurations have been excluded to avoid unnecessarily obscuring the subject matter of the invention. In this application, when component reference numerals are given in each figure, identical or similar components will be indicated by the same or similar reference numerals throughout the application.

[0052] Furthermore, the terms or words used in this specification and claims should not be construed as having a general meaning or a dictionary-based meaning, but rather should be interpreted as having a meaning and concept consistent with the technical concept of the invention, based on the principle that the inventor is able to properly define the concept of the terms to best describe his or her invention.

[0053] Figure 2 This is a plan view of a pouch-type secondary battery formed by the method of manufacturing a pouch-type secondary battery according to the present invention.

[0054] Reference Figure 1 and Figure 2 The bag 20 may include a sealing portion 25. The sealing portion 25 may form a closed loop extending along the outer periphery of the bag 20.

[0055] When the bag 20 is sealed, the sealing part 25 may refer to the portion of the bag 20 that is sealed. Alternatively, before the bag 20 is sealed, the sealing part 25 may refer to the portion of each of the bag body 21 and the bag cap 22 that is to be sealed.

[0056] More specifically, the sealing portion 25 may include a first region 25a corresponding to the lead film 40 and a second region 25b other than the first region 25a. The first region 25a and the second region 25b may be sealed by different methods, which will be described in detail later.

[0057] The second region 25b can be sealed by heat-fusion of the facing surface 24 of the bag body 21 and the bag cap 22.

[0058] The first region 25a can be sealed by thermal fusion with the lead film 40. More specifically, the lead film 40 attached to one surface of the electrode lead 32 can be thermally fused to the bag cap 22, and the lead film 40 attached to the other surface of the electrode lead 32 can be thermally fused to the facing surface 24 of the bag body 21.

[0059] The length L of the first region 25a relative to the width direction of the lead film 40 may be greater than or equal to the width W of the lead film 40. That is, the first region 25a may include not only the region directly facing the lead film 40, but also the region adjacent to it.

[0060] More specifically, when the length L of the first region 25a is equal to the width W of the lead film 40, the entire first region 25a can be thermally fused to the lead film 40 and sealed. On the other hand, when the length L of the first region 25a is greater than the width W of the lead film 40, the end of the first region 25a outside the lead film 40 can be sealed as the facing surface 24 of the bag body 21 that is thermally fused with the bag cap 22.

[0061] Figure 3 This is a flowchart illustrating a method for manufacturing a pouch-type secondary battery according to an embodiment of the present invention.

[0062] Reference Figure 3A method for manufacturing a pouch-type secondary battery according to one embodiment may include: a first sealing operation (S10) in which lead film 40 is fused to sealing portion 25 of pouch 20 by a laser beam; and a second sealing operation (S20) in which sealing portion 25 of pouch 20 is sealed.

[0063] The first sealing operation (S10) can be a pre-sealing operation, and the second sealing operation (S20) can be a main-sealing operation. That is to say, the first sealing operation (S10) and the second sealing operation (S20) can be performed sequentially.

[0064] The first sealing operation (S10) and the second sealing operation 20 can be performed at different stages, and the operation of injecting electrolyte into the receiving portion 23 of the bag 20 can be performed between the first sealing operation (S10) and the second sealing operation (S20).

[0065] More specifically, the first sealing operation (S10) thermally fuses the first region 25a and the lead film 40. The first sealing operation (S10) can be performed by the laser unit 60, which will be described later (see [link to laser unit 60]). Figure 5 )implement.

[0066] More specifically, the first sealing operation (S10) may include: a heating step, irradiating a first region 25a present in the sealing portion 25 of the bag 20 and corresponding to the lead film 40 with a laser beam, thereby heating the molten resin layers 21c and 22c of the lead film 40 and the first region 25a (see Figure 4 The bonding process involves compressing the first region 25a to bond the lead film 40 to the molten resin layers 21c and 22c. This will be described in detail later.

[0067] The second sealing operation (S20) can seal the entire sealing portion 25, that is, both the first region 25a and the second region 25b. The second sealing operation (S20) can be performed in a different manner than the first sealing operation (S10). The second sealing operation (S20) can be performed using the sealing tool 50, which will be described later (see [link to sealing tool]). Figure 4 ) to execute.

[0068] Figure 4 This is a schematic diagram illustrating an example of a laser unit used to perform the first sealing operation.

[0069] An apparatus for manufacturing a pouch-type secondary battery (hereinafter referred to as "manufacturing apparatus") according to an embodiment of the present invention may include a laser unit 60 for performing a first sealing operation (S10). The laser unit 60 may fuse the lead film 40 to the sealing portion 25 of the pouch 20, more specifically, to the first region 25a.

[0070] The bag body 21 and bag cap 22 constituting bag 20 may be made of laminates including inner resin layers 21c and 22c, respectively. More specifically, the bag body 21 and bag cap 22 may each include: outer resin layers 21a and 22a constituting a portion of the exterior of bag 20; inner resin layers 21c and 22c for sealing; and metal layers 21b and 22b located between the outer resin layers 21a and 22a and the inner resin layers 21c and 22c. For example, the outer resin layers 21a and 22a may include polyethylene terephthalate (PET) material, the metal layers 21b and 22b may include aluminum (AL) material, and the inner resin layers 21c and 22c may include polypropylene (PP) material.

[0071] The laser unit 60 can irradiate the first region 25a of the sealing portion 25 of the bag 20 with a laser beam and can compress the first region 25b. Therefore, the inner resin layers 21c and 22c of the first region 25a of the bag 20 can be melted and thermally fused to the lead film 40. Furthermore, the lead film 40 also has a resin material (e.g., polypropylene), so a portion of the lead film 40 can be melted by the laser beam emitted from the laser unit 60. Therefore, the thermal fusion between the lead film 40 and the inner resin layers 21c and 22c can be performed more reliably.

[0072] More specifically, the laser unit 60 may include a light source 61, a compression unit 62, and an optical unit 63.

[0073] Light source 61 can emit laser light with a beam shape. For example, light source 61 can be a laser diode. The laser beam emitted from light source 61 can be an infrared laser beam, and more specifically, an infrared laser beam with a wavelength of 808 nm to 980 nm.

[0074] Multiple light sources 61 can be provided. Some of the multiple light sources 61 can be located above the bag 20 and are referred to as upper light sources, while other light sources 61 can be located below the sealing part 25 and are referred to as lower light sources.

[0075] A laser beam emitted from the upper light source 61 can heat the lead film 40 attached to the upper side of the electrode lead 32 and the first region 25a of the bag cover 22. A laser beam emitted from the lower light source 61 can heat the lead film 40 attached to the lower side of the electrode lead 32 and the first region 25a of the bag body 21.

[0076] The compression section 62 can compress the first region 25a. The compression section 62 may be made of a transparent or translucent material that transmits the laser beam emitted from the light source 61. For example, the compression section 62 may include a quartz material with high strength. Therefore, the compression section 62 can sufficiently and firmly compress the first region 25a while allowing the laser beam to be transmitted through it.

[0077] The temperature of the compression section 62 of the laser unit 60 when compressing the first region 25a can be lower than the temperature of the heating strip 50 that compresses the sealing section 25 during the second sealing operation. This is because the laser beam emitted from the light source 61 is transmitted through the compression section 62, rather than heating the compression section. Therefore, energy loss can be reduced.

[0078] A pair of compression sections 62 may be provided. The pair of compression sections 62, which sandwich the first region 25a and face each other, can move in a direction that brings them closer together and compress the first region 25a. Obviously, the manufacturing equipment includes a lifting / lowering mechanism for raising and lowering the compression sections 62.

[0079] Figure 4 The illustration shows the light source 61 and the optical unit 63 moving together with the compression unit 62, but it is not limited to this. The compression unit 62 can move independently.

[0080] More specifically, the compression section 62 located above the bag 20 can compress downwards the first region 25a of the bag cover 22 and can be referred to as the upper compression section. The compression section 62 located below the bag 20 can compress upwards the first region 25a of the bag body 21 and can be referred to as the lower compression section.

[0081] A laser beam emitted from the upper light source 61 can pass through the upper compression section 62, and then thermally fuse the lead film 40 attached to the upper side of the electrode lead 32 and the inner resin layer 22c of the bag cover 22. A laser beam emitted from the lower light source can pass through the upper compression section, and then thermally fuse the lead film 40 attached to the lower side of the electrode lead 32 and the inner resin layer 21c of the bag body 21.

[0082] An optical section 63 may be positioned between the light source 61 and the compression section 62 along the path of the laser beam. The optical section 63 may refract and / or reflect the laser beam emitted from the light source 61 and guide it to the compression section 62. For example, the optical section 63 may include at least one of a lens and a reflector. The optical section 63 may be integrally formed with the compression section 62 or may be a separate component. Similar to the compression section 62, at least one pair of optical sections 63 may be provided.

[0083] The laser beam emitted from the light source 61 can be superimposed on each other after passing through the optical section 63 and the compression section 62, and can be simultaneously emitted onto the entire area existing in the bag body 21 and compressed by the compression section 62. In addition, this area can be heated from 200 degrees Celsius to 250 degrees Celsius by the beam.

[0084] The operation of the laser unit 60 during the first sealing operation (S10) will be described in detail below.

[0085] The first sealing operation (S10) can be started with the bag 20 aligned such that the first region 25a of the sealing portion 25 is located between at least one pair of compression portions 62.

[0086] The first sealing operation (S10) may include: a heating step, in which a laser beam is used to irradiate the first region 25a of the sealing portion 25 to heat the lead film 40, thereby melting the inner resin layers 21c and 22c of the first region 25a; and a bonding step, in which the first region 25a is compressed to bond the lead film 40 to the molten resin layers 21c and 22c.

[0087] The heating process can be performed when the laser beam emitted from the light source 61 is guided by the optical unit 63 to the compression unit 62, transmitted through the compression unit 62, and then emitted to the first region 25a. The internal resin layers 21c and 22c of the first region 25a can be melted by the laser beam emitted to the first region 25a.

[0088] Furthermore, since the irradiation time or intensity of the laser beam can be adjusted, the internal resin layers 21c and 22c of the first region 25a can be reliably melted even when the electrode lead 32 is cold. Therefore, since preheating of the electrode lead 32 is not required, a separate lead heater (not shown) is not needed.

[0089] The bonding process can be performed when the compression section 62 compresses the first region 25a. More specifically, a pair of compression sections 62 facing each other can move in a direction closer to each other and compress the first region 25a. Therefore, the internal resin layers 21c and 22c of the first region 25a, which are melted by the heating process, can be bonded to the lead film 40.

[0090] Since the first region 25a is irradiated with a laser beam while under compression, the heating process and the bonding process can be performed simultaneously. That is, the light source 61 can emit a laser beam while the first region 25a is compressed by the compression section 62.

[0091] Figure 5 This is a schematic diagram illustrating another example of a laser unit used to perform the first sealing operation.

[0092] According to one embodiment, the laser unit 60' does not include a separate optical section, and the compression section 62' can be used as the optical section. For example, the compression section 62' itself can act as a reflector or lens. Therefore, the light source 61 can emit a laser beam directly toward the compression section 62', and the laser beam can be refracted or reflected within the compression section 62' before being emitted into the first region 25a. Thus, the laser unit 60' has a compact size, and its structure is simplified.

[0093] Figure 6 This is a schematic diagram illustrating a sealing tool used to perform the second sealing operation.

[0094] An apparatus for manufacturing a pouch-type secondary battery according to an embodiment of the present invention (hereinafter referred to as "manufacturing apparatus") may include a sealing tool 50 for performing a second sealing operation (S20). The sealing tool 50 seals the sealing portion 25 by thermally fusing the pouch body 21 and the pouch cap 22.

[0095] The sealing tool 50 may include at least one pair of heating strips 50 positioned facing each other while clamping the bag 20. For convenience, the sealing tool and the heating strips are referred to by the same reference numeral "50". Clearly, the sealing tool 50 includes a heater for heating the heating strips 50 and a lifting / lowering mechanism for raising and lowering the heating strips 50.

[0096] At least one pair of heating bars 50 in a heated state can move in a direction that brings them closer together and compress the sealing portion 25 of the bag 20. Therefore, the inner resin layer 21c of the sealing portion 25 of the bag body 21 and the inner resin layer 22c of the sealing portion 25 of the bag cap 22 can melt and thermally fuse together.

[0097] The heating strip 50 can compress the first region 25a and the second region 25b together.

[0098] Figure 7 This is a flowchart illustrating a method for manufacturing a pouch-type secondary battery according to another embodiment of the present invention.

[0099] In this embodiment, the first sealing operation (S10) is the same as the first sealing operation (S10) in the above embodiment, and therefore its description can be applied here.

[0100] Reference Figure 7 According to this embodiment, the second sealing operation (S20') can seal only the second region 25b of the sealing portion 25 of the bag 20, excluding the first region 25a. That is, the heating strip 50 can compress only the second region 25b, excluding the first region 25a.

[0101] Therefore, the internal resin layers 21c and 22c of the first region 25a, which have been sealed by the laser unit 60, can be prevented from melting or deforming again, thus maintaining a high sealing quality of the first region 25a.

[0102] also, Figure 7 The illustration shows the first sealing operation (S10) and the second sealing operation (S20) being performed in this order, but the implementation is not limited to this. The first sealing operation (S10) may be performed after the second sealing operation (S20').

[0103] The technical concept of the invention has been described for illustrative purposes only, and those skilled in the art will understand that various changes and modifications can be made without departing from the essential features of the invention.

[0104] Therefore, the embodiments of the present invention are to be considered illustrative rather than restrictive, and the technical spirit of the present invention is not limited to the foregoing embodiments.

[0105] The scope of protection of this invention is defined by the appended claims, and all technical concepts within their equivalents should be understood to be included within the scope of this invention.

[0106] [Label Explanation]

[0107] 10: Bag-type secondary batteries; 20: Bag-type secondary batteries

[0108] 21: Bag body 22: Bag flap

[0109] 23: Receiving section 24: Facing surface

[0110] 25: Sealing part 25a: First area

[0111] 25b: Second Region 30: Electrode Assembly

[0112] 31: Connector; 32: Electrode lead

[0113] 40: Lead wire film; 50: Sealing tool

[0114] 60: Laser unit; 61: Light source

[0115] 62: Compression section; 63: Optical section.

Claims

1. A method for manufacturing a pouch-type secondary battery, the method comprising: The first sealing operation involves fusing the lead film of the electrode lead attached to the electrode assembly to the sealing portion of the bag containing the electrode assembly. as well as The second sealing operation involves sealing the bag's sealing section. The first sealing operation includes: In the heating process, a laser beam is used to irradiate the area present in the sealing portion of the bag and corresponding to the lead film, thereby heating the lead film and melting the resin layer in the area; and In the bonding process, the region is compressed, thereby bonding the lead film and the molten resin layer together, and In the second sealing operation, the sealing portion is compressed by a heating strip, so that the second sealing operation is performed in a different manner than the first sealing operation.

2. The method according to claim 1, wherein the first sealing operation and the second sealing operation are performed sequentially.

3. The method of claim 2, wherein the area sealed in the first sealing operation is included in the sealing portion sealed in the second sealing operation.

4. The method of claim 1, wherein the length of the region relative to the width direction of the lead film is greater than or equal to the width of the lead film.

5. The method according to claim 1, wherein the heating step and the bonding step are performed simultaneously.

6. The method according to claim 1, wherein the laser beam is an infrared laser beam having a wavelength of 808 nm to 980 nm.

7. The method of claim 1, wherein the laser unit performing the first sealing operation comprises: A light source configured to emit a laser beam; and A compression section that compresses the area present in the sealing section of the bag and corresponding to the lead film, the compression section having a transparent or translucent material that transmits laser beams.

8. The method according to claim 7, wherein the light source emits a laser beam while the region is compressed by the compression section.

9. The method of claim 7, wherein the temperature of the compression section when compressing the region is lower than the temperature of the heating strip when compressing the sealing section.

10. The method of claim 1, wherein the region sealed in the first sealing operation is excluded from the sealing portion sealed in the second sealing operation.

11. An apparatus for manufacturing pouch-type secondary batteries, the apparatus comprising: A laser unit configured to fuse a lead film of an electrode lead attached to an electrode assembly to a sealing portion of a bag containing the electrode assembly. as well as A sealing tool configured to seal the sealing portion of the bag after the lead film has been fused to the sealing portion. The laser unit includes: A light source configured to emit a laser beam; and A compression section, configured to compress a region present in the sealing portion of the bag and corresponding to the lead film, the compression section having a transparent or translucent material that transmits laser beams, and The sealing tool includes a heating strip that compresses the sealing portion.

12. The device of claim 11, further comprising an optical unit configured to guide a laser beam emitted from the light source to the compression unit.

13. The device according to claim 11, wherein the compression section is made of quartz material.

14. The device of claim 11, wherein the compression section refracts or reflects the laser beam emitted from the light source.

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