Pouch-type rechargeable battery and method for manufacturing the same

Abstract

According to one embodiment of the present invention, a method for manufacturing a pouch-type secondary battery and a pouch-type secondary battery manufactured thereby can be provided, comprising: a forming step of forming a housing portion in which an electrode assembly is mounted by indenting a part of the area of ​​the pouch; a loading step of mounting the electrode assembly into the housing portion; and a sealing step of forming a sealing portion between the stacked upper pouch and lower pouch by pressurizing a sealing area outside the housing portion and at a predetermined distance from the edge of the housing portion, wherein at least a portion of the sealing step is performed while an upper and lower gap is maintained between the stacked pouches in an adhesion area located between the edge of the housing portion and the sealing area.

Description

Technical Field

[0001] The present invention relates to a pouch-type secondary battery and a method for manufacturing the same, and more specifically, to a pouch-type secondary battery capable of effectively eliminating the formation of an adhesion part in an adhesion area and a method for manufacturing the same.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0087118 filed on July 5, 2023, and all the contents described in the corresponding Korean patent application are incorporated herein by reference.

Background Art

[0003] A secondary battery is a battery that can be repeatedly used through a discharging process of converting chemical energy into electrical energy and a charging process of converting electrical energy into chemical energy.

[0004] Secondary batteries can include nickel-cadmium (Ni-Cd) batteries, nickel-metal hydride (Ni-MH) batteries, lithium-metal batteries, lithium-ion (Li-Ion) batteries, and lithium-ion polymer batteries (hereinafter referred to as "LIPBs"), etc.

[0005] Lithium secondary batteries have a cycle life of about 500 or more cycles and a short charging time of about 1 to 2 hours, and can be made lighter because they are about 30% to 40% lighter than nickel-metal hydride batteries. Among existing secondary batteries, they have the highest voltage per unit cell (30 to 37V) and excellent energy density, so they can have characteristics optimized for mobile devices.

[0006] Lithium secondary batteries can be manufactured into pouch-type secondary batteries in which a battery cell or an electrode assembly is sealed with a pouch made of an aluminum sealing material.

[0007] A pouch-type secondary battery may include an electrode assembly housed in a pouch, which is a sealing material; leads from which electrode tabs of electrodes on the electrode assembly are electrically connected and led out of the pouch; and an insulating film that electrically insulates the leads. In particular, the pouch can perform the function of sealing the electrode assembly housed inside by heat-sealing the inner surface of the pouch together with the insulating film provided on the leads of the electrode assembly, or by directly heat-sealing the inner surfaces of the pouch to each other to form a sealing portion. The insulating film is generally made of polypropylene (PP) film.

[0008] Of course, the pouch has an insulating film coated on the top and bottom surfaces of a metal sheet, especially an aluminum sheet, and during heat sealing, the opposing insulating films are heat-sealed together to form a sealing area. The insulating film of the pouch, especially the inner insulating film, is generally made of polypropylene film.

[0009] Pouch sealing performs the function of sealing a specific space within the pouch that contains the electrolyte. When the electrode assembly is repeatedly charged and discharged, gas is generated and the pressure inside the pouch increases, so for this reason, high strength is required for pouch sealing.

[0010] On the other hand, during heat sealing of the pouch, the polypropylene (PP) film is melted and diffused to adhere to it. The polypropylene film not only adheres to the pouch, but also prevents corrosion of the metal layer of the pouch, such as aluminum, by separating it from the electrolyte, and prevents current from flowing through the pouch and increasing its resistance.

[0011] Figures 1 and 2 illustrate a typical sealing method for pouch-type secondary batteries and the formation of an adhesion area in the adhesion region.

[0012] Pouch 1 comprises an inner insulating coating layer 1a and a core layer 1b. The core layer 1b includes a core layer made of a metal material, which can generally be made of aluminum. The core layer may further include an outer insulating coating layer.

[0013] The pouches are sealed by applying heat and pressure to them through a sealing tool 2, sealing the space between the pouches. Specifically, the stacked upper and lower pouches 1A, 1B, or pouch case are heat-fused together vertically through the upper sealing tool 2A and the lower sealing tool 2B, and the area corresponding to the sealing tools can be called the sealing area 3. In other words, the insulating coating layer 1a melts due to the heat and pressure in the sealing area, forming the sealing portion 6. To put it another way, the opposing insulating coating layers 1a melt and then solidify to form the sealing portion 6. This sealing is performed with the electrode assembly 8 installed inside, and a housing portion 1C is formed in the pouch to accommodate the electrode assembly 8.

[0014] A predetermined adhesion region 4 is provided between the cell region 5, where the electrode assembly 8 is located, and the sealing region 3. Specifically, a predetermined adhesion region 4 is provided between the edge 1D of the housing portion and the sealing region 3, but an unintended sealing portion, i.e., an adhesion portion 7, may be formed in the adhesion region. That is, the insulating material melted in the sealing region 3 may move to the adhesion region 4 and bond with each other to form an adhesion portion 7.

[0015] Unlike the sealing portion 6 formed by pressurization in the sealing region, the bonding thickness of the insulating material at the bonding portion 7 in the bonding region 4 is relatively large, resulting in weak high-temperature durability. Furthermore, the internal pressure of the pouch may increase due to subsequent activation processes, and if the bonding at the bonding portion breaks at this time, the metal pouch core 1b may be exposed to the electrolyte filling the inside of the pouch, potentially causing insulation failure.

[0016] As shown in Figure 2, leads 8a may be provided at both or one end of the electrode assembly 8 in the longitudinal direction. The leads 8a are made of a conductive material and are provided so as to penetrate the pouch 1 and be exposed to the outside. An insulating film 9 is interposed above and below the leads 8a, and a sealing region 3 and a sealing portion 6 are formed across the insulating film 9. Here, the sealing over the portion through which the leads 8a penetrate can be called top sealing. And the sealing that is aligned with the longitudinal direction of the electrode assembly 8 in correspondence with the top sealing can be called side sealing.

[0017] Problems caused by the formation of adhesion points 7 can occur in side sealing as well, but they can be even more noticeable in top sealing. This is because in side sealing, one sealing point is formed by heat fusion between the pouches, while in top sealing, two sealing points are formed: one between the pouches and one above and below due to heat fusion between the pouch and the insulating film. In the case of top sealing, the thickness of the sealing point where insulating film 9 is interposed differs from the sealing point where insulating film 9 is not interposed, depending on the thickness of the lead and the upper and lower insulating films. For this reason, top sealing is more difficult than side sealing. Furthermore, it can be said that the possibility of adhesion points forming is even higher in top sealing.

[0018] Therefore, there is a need to provide a method for manufacturing a secondary battery, a manufacturing apparatus, and a secondary battery manufactured using the same, which can effectively prevent problems caused by adhesions 7 in the adhesion region 4 that may be generated during pouch sealing, particularly the top sealing process. [Overview of the Initiative] [Problems that the invention aims to solve]

[0019] The present invention aims to solve the problems of conventional pouch-type rechargeable batteries.

[0020] Through one embodiment of the present invention, it is possible to provide a method for manufacturing a secondary battery, a manufacturing apparatus, and a secondary battery manufactured using the same, which can easily and simply effectively eliminate the formation of adhesive portions in the adhesion area.

[0021] Through one embodiment of the present invention, it is possible to provide a method for manufacturing a secondary battery, a manufacturing apparatus, and a secondary battery manufactured using the same, which can be applied within the conventional secondary battery manufacturing process without adding any additional steps.

[0022] Through one embodiment of the present invention, it is possible to provide a method for manufacturing a secondary battery, a manufacturing apparatus, and a secondary battery manufactured using the same, which can effectively prevent the formation of adhesion in the lead region through which the leads of the electrode assembly penetrate, particularly in the adhesion regions located on both sides of the lead region. [Means for solving the problem]

[0023] To achieve the aforementioned objectives, according to one embodiment of the present invention, a method for manufacturing a pouch-type secondary battery is provided, comprising: a forming step of forming a housing portion in which an electrode assembly is mounted by indenting a portion of the pouch; a loading step of mounting the electrode assembly into the housing portion; and a sealing step of forming a sealing portion between the stacked upper pouch and lower pouch by pressurizing a sealing region located outside the housing portion at a predetermined distance from the edge of the housing portion, wherein at least a portion of the sealing step is performed while an upper and lower gap is maintained between the stacked pouches in an adhesion region located between the edge of the housing portion and the sealing region.

[0024] The sealing step may include top sealing, which seals the surface on which the leads of the electrode assembly penetrate the pouch, and side sealing, which seals the surface on which the leads of the electrode assembly do not penetrate the pouch.

[0025] In side sealing, a sealing portion by direct heat fusion can be formed between the upper pouch and the lower pouch. In top sealing, since a lead is interposed between the upper pouch and the lower pouch, a sealing portion can be directly formed between the upper pouch and the lower pouch only in some regions.

[0026] To form and maintain the vertical gap, an inhalation step of inhaling the upper pouch upward and the lower pouch downward in the adhesion region through an inhalation nozzle can be included. That is, the sealing step can include the inhalation step.

[0027] The inhalation step is preferably performed after the pressurization starts through the sealing block in the sealing step.

[0028] The inhalation step can be performed until the pressurization ends or can be performed for a predetermined time after the pressurization ends.

[0029] It is preferable to exclude the inhalation step through the inhalation nozzle in the lead region of the pouch where the lead of the electrode assembly is mounted. In particular, it is preferable to exclude the inhalation step in the adhesion region within the lead region. This is because an insulating film or a protective tape is interposed between the lead and the pouch, and such inhalation may damage the adhesion of the protective tape.

[0030] The inhalation step is preferably performed in the adhesion regions located on both sides of the lead region. In particular, it is preferable to perform inhalation at positions deviated from both sides of the protective tape. This is because during top sealing, direct heat fusion between the upper pouch and the lower pouch is performed in such regions.

[0031] The vertical gap can be formed by a stepped portion having a lower depression depth than the accommodating portion in the adhesion region and having a step with the accommodating portion.

[0032] The stepped portion can be formed together with the accommodating portion in the forming step.

[0033] The housing portion and the stepped portion may be formed simultaneously or sequentially during the forming stage.

[0034] It is preferable that the stepped portion is formed in the lead region of the pouch where the leads of the electrode assembly are attached.

[0035] It is preferable that the stepped portion is formed in the attachment regions located on both sides of the lead region.

[0036] To achieve the aforementioned objectives, according to one embodiment of the present invention, a pouch-type secondary battery can be provided which includes a pouch case having a metal layer and insulating coating layers formed on its lower and upper surfaces, and a housing portion in which a portion is recessed; and an electrode assembly having leads that are attached to the housing portion and exposed to the outside of the pouch case when the sealing portions of the upper and lower stacked pouch cases are pressurized and a sealing portion is formed by heat fusion, wherein when the sealing portion is formed, the formation of an adhesion portion is limited in the adhesion region located between the edge of the housing portion and the sealing region by an upper and lower gap formed between the upper and lower stacked pouch cases. That is, due to the upper and lower gap, the adhesion region of the upper pouch is located above the sealing portion, and the adhesion region of the lower pouch is located below the sealing portion. Due to this positional difference, the formation of an adhesion portion connecting the upper and lower pouches in the adhesion region can be significantly reduced.

[0037] The upper and lower gap can be formed by drawing the upper pouch case upward and the lower pouch case downward through the suction nozzle in the adhesion area.

[0038] Inhalation through the suction nozzle can be prevented in the lead area of ​​the pouch case to which the lead is attached.

[0039] It is preferable that suction is performed through the suction nozzle in the attachment areas located on both sides of the lead area.

[0040] Preferably, the upper and lower gap is formed by a stepped portion that has a lower recess depth than the housing portion in the adhesion region and has a step difference with respect to the housing portion.

[0041] The stepped portion is formed during the pouch forming stage, and is formed by deforming the shape of the pouch, similar to the housing portion. Therefore, in the final pouch-type secondary battery, the stepped portion and the housing portion can be distinguished from other parts in terms of shape.

[0042] It is preferable that the stepped portion is provided in the lead area of ​​the pouch case where the leads of the electrode assembly are attached.

[0043] The width of the stepped portion in the lead region is preferably greater than the width of one side of the lead portion of the electrode assembly. The stepped portion may be formed to be adjacent to the sealing region in the lead region.

[0044] It is preferable that the stepped portion is formed in the attachment regions located on both sides of the lead region of the pouch case to which the leads of the electrode assembly are attached.

[0045] The formation of the stepped portion can be eliminated in the lead region of the pouch case where the leads of the electrode assembly are attached. [Effects of the Invention]

[0046] Through one embodiment of the present invention, it is possible to provide a method for manufacturing a secondary battery, a manufacturing apparatus, and a secondary battery manufactured using the same, which can easily and simply effectively eliminate the formation of adhesive portions in the adhesion area.

[0047] Through one embodiment of the present invention, it is possible to provide a method for manufacturing a secondary battery, a manufacturing apparatus, and a secondary battery manufactured using the same, which can be applied within a conventional secondary battery manufacturing process without adding any additional steps.

[0048] Through one embodiment of the present invention, it is possible to provide a method for manufacturing a secondary battery, a manufacturing apparatus, and a secondary battery manufactured using the same, which can effectively prevent the formation of adhesion in the lead region through which the leads of the electrode assembly penetrate, particularly in the adhesion regions located on both sides of the lead region. [Brief explanation of the drawing]

[0049] [Figure 1] This diagram illustrates how the sealing and adhesion parts are formed during the conventional pouch sealing process. [Figure 2] This diagram illustrates how the adhesive portion is formed using a conventional pouch. [Figure 3] This diagram illustrates a flow chart of a method for manufacturing a pouch-type secondary battery according to one embodiment of the present invention. [Figure 4] This figure illustrates a pouch sealing according to one embodiment of the present invention. [Figure 5] This diagram illustrates how a stepped section is formed during the pouch forming process. [Figure 6] The diagram illustrates how a stepped section is formed in the lead region by the top sealing. [Figure 7] This diagram illustrates how a stepped section is formed through the suction nozzle during the sealing process. [Figure 8] The diagram illustrates how a stepped section is formed in the lead region by the top sealing. [Modes for carrying out the invention]

[0050] The following will describe in more detail an embodiment of the present invention, specifically a sealing device and a sealing method, with reference to the attached drawings.

[0051] First, we will explain in more detail the manufacturing method of pouch-type rechargeable batteries with reference to Figure 3.

[0052] The packaging process for pouch-type rechargeable batteries generally includes manufacturing the electrode assemblies, forming the pouches in which the electrode assemblies will be housed, placing the electrode assemblies into the pouches, and sealing the pouches.

[0053] The forming step (S10) may be a process in which a portion of the pouch is indented to form a housing into which the electrode assembly is mounted.

[0054] The loading stage (S20) may be the process of loading a pre-fabricated electrode assembly into the storage compartment of the pouch and attaching it.

[0055] After the loading stage (S20) is completed, a sealing stage (S30) may be performed to seal the pouch. The sealing stage may include a top sealing process in which the surface through which the leads penetrate the pouch and a side sealing process in which the surface through which the leads do not penetrate the pouch is sealed.

[0056] In the case of a rectangular secondary battery, one of the two sides on which the leads do not penetrate the pouch can be formed by the folding of a continuous pouch. Therefore, a side sealing process is unnecessary in this area. The side sealing process on the other side can be performed under vacuum after the subsequent electrolyte injection and degassing processes.

[0057] In the sealing stage (S30), the sealing area of ​​the pouch is pressurized through a sealing tool to form a sealing section between the laminated or overlapping upper and lower pouches.

[0058] It is preferable that at least a portion of the sealing step (S30) is performed while maintaining an upper and lower gap between the stacked pouches.

[0059] The upper and lower gap may be intentionally formed and maintained during the sealing stage (S30). Alternatively, the upper and lower gap may be formed during the forming stage (S10) and then maintained during the sealing stage (S30). In other words, in either case, it is preferable that at least a portion of the sealing stage (S30) is performed while the upper and lower gap is maintained.

[0060] Figure 4 illustrates a conceptual pouch sealing structure and method according to one embodiment of the present invention.

[0061] As illustrated, the pouch sealing structure and method for this embodiment can be said to be similar to the conventional pouch sealing structure and method illustrated in Figure 1.

[0062] With the upper pouch 11 and the lower pouch 12 overlapping, the sealing tool 20, i.e., the upper sealing block 21 and the lower sealing block 22, forms a sealing portion 60 in the sealing area 30. At this time, the electrode assembly 80 is located in the housing portion 10C between the upper pouch 11 and the lower pouch 12.

[0063] The aforementioned housing portion 10C is formed by forming a flat sheet-shaped pouch. More specifically, a portion of the pouches 11 and 12 is recessed to form the housing portion 10C into which the electrode assembly 80 is inserted and mounted.

[0064] The storage portion 10C may be formed in only one of the upper pouch 11 and the lower pouch 12, or in both. Accordingly, the recess depth of the storage portion 10C may vary. The upper pouch 11 and the lower pouch 12 may be separate sheet shapes, or they may be a single sheet folded and stacked on top of each other. In the latter case, side sealing of the folded portion is unnecessary.

[0065] Since the storage portion 10C is formed by a depression in a flat surface, a boundary between the flat surface and the depression, i.e., the storage portion edge 10D, can be formed. The storage portion edge 10D can be formed in a form where the pouch is gently folded.

[0066] An adhesion region 40 is provided between the sealing region 30 and the cell region 50. The adhesion region 40 can be described as a safety distance that protects the electrode assembly 80 by preventing the shock, heat, and pressure during sealing in the sealing region 30 from being transmitted to the cell region 50.

[0067] The pouches 11 and 12 may include an inner insulating coating layer 11a and a core layer 11b. When forming a sealing portion 60 in the sealing region 30 through the sealing tool 20, it is common for a portion of the insulating material molten in the insulating coating layer 11a to move to the adhesion region 40 and form an adhesion portion. This is because, as shown in Figure 1, according to conventional sealing methods and sealing structures, the upper pouch 11 and the lower pouch 12 are stacked vertically not only in the sealing region 3 but also in the adhesion region 4, and the molten insulating material can easily move over the weight of the upper pouch 11 and move to the adhesion region 4. In other words, the molten insulating material can pry open the space between the stacked upper pouch 11 and lower pouch 12 in the adhesion region 4 and move, thereby forming an adhesion portion.

[0068] In this embodiment, a vertical gap 13 is intentionally formed between the upper pouch 11 and the lower pouch 12 in the adhesion region 40. The height of the vertical gap 13 can be made noticeably larger than the thickness of the upper pouch 11 and the lower pouch 12. Of course, it is preferable that the height of the vertical gap 13 be made smaller than the vertical height of the containment section.

[0069] Specifically, the height of the upper and lower gap is formed to be greater than the sum of the thicknesses of the upper and lower pouches, and preferably the height of the upper and lower gap is at least twice the sum of the thicknesses of the upper and lower pouches.

[0070] The upper and lower gap 13 can be formed through a stepped portion 14 formed between the sealing region 30 and the cell region 50. The stepped portion 14 can be formed in the attachment region 40. That is, the sealing region 30 is not connected to the cell region 50 through a single inclined surface, but rather the sealing region 30 is connected to the cell region 50 through two inclined surfaces by the stepped portion 14. It can be said that a stepped portion 14 having a horizontal surface is interposed between the two inclined surfaces.

[0071] When an upper and lower gap 13 is intentionally formed in the adhesion region 40, the molten insulating material does not need to move in the adhesion region 40 while overcoming the weight of the upper pouch 11. In particular, most of the molten insulating material that moves into the upper and lower gap 13 flows into the lower pouch 12 due to its own weight. This is because the molten insulating material moves almost entirely along the inner surface of the lower pouch 12 and solidifies, and the solidified insulating material is separated from the inner surface of the upper pouch 12 by the upper and lower gap 13. In other words, generally, solidified insulating material solidifies while connecting the inner surfaces of the lower pouch and the upper pouch to form an adhesion portion, but according to this embodiment, the formation of such an adhesion portion can be eliminated by the upper and lower gap 13.

[0072] The upper and lower gaps 13 can be formed or maintained in various forms. In other words, the stepped portion 14 can be formed or maintained in various forms. In any case, it is preferable to ensure an extra length between the sealing region 30 and the cell region 50 for the stepped portion 14 to be formed.

[0073] Figure 5 illustrates one embodiment for forming and maintaining the upper and lower gap 13.

[0074] As illustrated, the upper and lower gaps can be formed through the forming of pouch 10. That is, the upper and lower gaps can be pre-formed during the forming stage (S10). The pre-formed upper and lower gaps can be maintained during the sealing stage (S30).

[0075] As mentioned above, the storage portion 10C of the pouch 10 can be formed by indenting a portion of the flat pouch through forming. Similarly, the upper and lower gaps can be formed by indenting a portion of the flat pouch in the adhesive region adjacent to the storage portion 10C. In this case, it is preferable that the indentation depth for the upper and lower gaps is smaller than the indentation depth of the storage portion. That is, a stepped portion 14 can be formed in the adhesive region 40 through forming.

[0076] Figure 5 illustrates an example in which a housing section 10C and a stepped section 14 for forming the upper and lower gap 13 are simultaneously formed by a single forming process.

[0077] The flat, sheet-like pouch 10 is mounted on dies 23 and 24 on both sides and secured by strippers 25 and 26 on both sides. The punch 27 pressurizes the pouch 10 to form a recess corresponding to the shape of the punch 27. That is, the recess formed at this time can be called the containment section 10C.

[0078] The punch 27, which consists of a central pressurizing portion 27a corresponding to the housing portion 10C and an edge pressurizing portion 27b corresponding to the stepped portion 14, can simultaneously form the housing portion and the stepped portion.

[0079] Of course, the storage section and the stepped section can be formed sequentially through multiple forming processes. For example, the storage section 10C can be formed first by forming, and then the stepped section 14 can be formed at the edge of the storage section 10C by forming. Alternatively, for example, forming for indentation can be performed on the entire surface with an indentation depth corresponding to the indentation depth of the upper and lower gap, and then forming can be performed only on the central part with an indentation depth corresponding to the depth of the storage section. In other words, a stepped section can be formed by shallowly indenting a wide area, and then the storage section can be formed by deeply indenting a narrow area in the central part of the wide area.

[0080] In any case, according to this embodiment, the stepped portion 14 in the adhesion region can be pre-formed through the forming process of the pouch during the pouch molding process. That is, the upper and lower gap 13 can be formed inside the pouch through the stepped portion 14 formed in the pouch.

[0081] The stepped portion 14 may be formed on both the upper pouch 11 and the lower pouch 12, or it may be formed on only one of them. When the stepped portion 14 is formed on both the upper pouch 11 and the lower pouch 12, a sufficient vertical separation can be formed even if the recess depth is small.

[0082] On the other hand, since the electrode assembly 80 is generally rectangular in shape, the housing section 10C is also generally formed in a rectangular shape to correspond to this. The electrode assembly 80 is provided with two leads that are exposed to the outside of the pouches 11 and 12, and the two leads may protrude in one direction or in opposite directions. The sealing of the parts of the electrode assembly 80 without leads is called side sealing, and the sealing of the parts with leads can be called top sealing.

[0083] When the upper and lower pouches are sealed separately, there are two side sealing points, and when single pouches overlap and are sealed, there may be one side sealing point. However, in either case, there may be two top sealing points. Of course, if two leads protrude in the same direction, there may be only one top sealing point.

[0084] The upper and lower gaps 13 formed by the forming process may be formed on all surfaces where side sealing and top sealing are performed, and may be formed only on the surfaces where top sealing is performed.

[0085] Figure 6 illustrates an example in which an upper and lower gap 13 is formed for top sealing.

[0086] For the sake of explanation, Figure 6 shows the state after top sealing, with the upper pouch removed and the electrode assembly 80 housed in the lower pouch 12.

[0087] In side sealing, the upper and lower pouches are sealed directly by heat fusion, while in top sealing, leads 80a and 80b and an insulating film 90 are interposed between the upper and lower pouches. The insulating film is very firmly bonded to the leads, and a sealing region 30 can be formed across the insulating film.

[0088] In top sealing, similar to side sealing, a sealing region 30 is formed in the pouch, and it is preferable that an adhesion region 40 is provided between the edge of the housing section, i.e., the cell region 50, and the sealing region 30. In this case, the leads 80a and 80b can protrude from the housing section 10C through the adhesion region 40 and the sealing region 30 to the outside of the pouch 12. Therefore, in top sealing, the region of the pouch through which the leads pass, including the adhesion region 40 and the sealing region 30, can be called the lead region 55.

[0089] In the sealing area 30 of the top sealing, a sealing portion is formed between the lower pouch 12, the insulating film 90, the leads 80a and 80b, the insulating film 90, and the upper pouch 11. Then, in the adhesion area 40, an adhesion portion may be formed between the lower pouch 12 and the insulating film 90, between the lower insulating film 90 and the leads 80a and 80b, between the upper insulating film 90 and the leads 80a and 80b, and between the leads 80a and 80b and the upper pouch 11.

[0090] Therefore, it can be said that the number of sealing portions formed in the sealing region 30 and the number of attachment portions that can be formed in the attachment region are greater in top sealing than in side sealing. For this reason, it is preferable to form a stepped portion 14 in the attachment region 40 in the lead region 55 to form an upper and lower gap.

[0091] The width of the stepped portion 14 is preferably greater than the width of the lead 80a. Furthermore, the width of the stepped portion 14 is preferably greater than the width of one side of the electrode assembly on which the lead 80a is provided. In particular, the width of the stepped portion 14 is preferably greater than the width of the insulating film 90, as shown in Figure 6.

[0092] Here, the stepped portion 14 may be further extended on both sides of the insulating film 90. For example, the stepped portion 14 may be formed to have the same width as the sealing area 30 in which the top sealing is performed.

[0093] The stepped sections 14 formed on both sides of the width of the housing section 10C are not connected to the housing section 10C. The stepped sections 14 that are included within the width range of the housing section 10C are formed in a two-step staircase manner between the sealing area 30 and the housing section 10C. On the other hand, the stepped sections 14 formed on both sides of the width of the housing section 10C may be formed in a single-step staircase manner.

[0094] On the other hand, the insulating film 90 provided in the lead region 55 may be provided penetrating the sealing region 30 in the front-to-back and left-to-right directions. That is, a part of the insulating film 90 is provided on the outside of the sealing region 30, and a part is provided on the inside of the sealing region 30. Therefore, it is preferable that a part of the insulating film 90 is located on the stepped portion 14 formed in the lead region 55. Also, it is preferable that the height of the upper and lower gap formed by the stepped portion 14 is greater than the height of the leads 80a and 80b. Therefore, the leads 80a and 80b are directly thermally fused with the pouches 11 and 12 in the lead region 55 through the stepped portion 14 or the upper and lower gap, and no sealing portion is formed. This means that no adhesion portion is formed between the leads 80a and 80b and the pouches 11 and 12 in the lead region 55.

[0095] As shown in Figure 6, it is preferable that the width of the insulating film 90 is greater than the width of the lead 80a so as to cover the entire lead 80a. However, it is preferable that the width of the insulating film 90 is smaller than the width of one side of the electrode assembly 80 on which the leads 80a and 80b are provided. Therefore, even with top sealing, a sealing portion may be formed by direct heat fusion between the pouches in the areas away from both ends of the insulating film 90. For this reason, adhesion may also occur. Therefore, it is preferable that an upper and lower gap is formed by the stepped portion 14 in the adhesion regions 40 on both sides of the lead region 55 to prevent the formation of adhesion.

[0096] In particular, it is preferable that the width of the stepped portion 14 in the lead region 55 is even greater than the width of one side of the electrode assembly 80. That is, it is preferable that the stepped portion 14 in the lead region 55 extends further to both sides at both ends of the electrode assembly 80 and is also formed in the attachment region 40.

[0097] On the other hand, in the adhesion area within the lead region 55, particularly in the area covered by the insulating film 90, the presence of the insulating film 90 may prevent the formation of an upper and lower gap due to the stepped portion 14. This is because the insulating film 90 can sufficiently prevent the formation of an adhesion area between the pouch and the lead.

[0098] However, in order to facilitate the formation of the stepped portion 14, it is preferable to form a continuous stepped portion 14 not only in the lead region 55 but also in the attachment regions 40 on both sides.

[0099] The upper and lower gap 13 between the upper pouch 11 and the lower pouch 12 can be formed through a stepped portion 14 formed by forming, as described above, or through the suction nozzles 101 and 102.

[0100] As shown in Figure 7, when forming the sealing portion 60 through the sealing tool 20, a portion of the upper pouch 11 can be drawn upwards through the suction nozzles 101 and 102, and a portion of the lower pouch 12 can be drawn downwards.

[0101] In particular, in the adhesion region 40 located between the sealing region 30 and the cell region 50, the upper pouch can be pulled upward through the upper suction nozzle 101, and the lower pouch can be pulled downward through the lower suction nozzle 102.

[0102] When the upper pouch 11 and lower pouch 12 are moved vertically through the suction nozzles 101 and 102, the upper pouch 11 and lower pouch 12 in the sealing area 30 may also be moved vertically. Therefore, the timing of the pouch adsorption through the suction nozzles may be important.

[0103] In this embodiment, it is preferable that suction or adsorption through the suction nozzle and vertical movement of the pouch are performed after pressurization has begun through the sealing blocks 21 and 22. That is, when the upper pouch 11 and the lower pouch 12 are pressurized and tightly adhere to each other in the sealing region 30, the sealing portion 60 can be smoothly formed even if suction is performed in the adhesion region 40.

[0104] Furthermore, once suction is complete, the upper pouch 11 and lower pouch 12 tend to return to their original positions, that is, to a shape where they overlap. Therefore, it is preferable that suction is maintained for a predetermined time after the pressurization of the sealing blocks 21 and 22 is completed. In other words, it is preferable that the upper and lower gap 13 is maintained until a predetermined time has elapsed after the pressurization is completed. This can be said to provide a sufficient time margin for the insulating material, which has been melted after thermal pressurization, to flow into the adhesion region 40 and then harden sufficiently without forming an adhesion portion.

[0105] Figure 8 illustrates the region where an upper and lower gap is formed through the suction nozzles 101 and 102.

[0106] As illustrated, the formation of an upper and lower gap through the suction nozzles 101 and 102 can be applied to top sealing. In particular, the upper and lower gap can be formed in the adhesion region 40 near the sealing region 30.

[0107] The upper and lower gaps 13 do not necessarily have to be formed in the aforementioned lead region 55. That is, the upper and lower gaps 13 can only be formed in the region where the upper pouch 11 and the lower pouch 12 are directly fused together.

[0108] The upper and lower gap 13 can be formed by the suction nozzles 101 and 102 adsorbing onto the surfaces of the upper pouch 11 and the lower pouch 12 and moving the surfaces vertically. For this purpose, the suction nozzles 101 and 102 must move vertically to approach the upper pouch 11 and the lower pouch 12, and preferably move vertically in the opposite direction after adsorption.

[0109] For top sealing, the sealing blocks 21 and 22 can move vertically. The sealing is performed by the sealing blocks 21 and 22 making close contact with the surfaces of the upper pouch 11 and the lower pouch 12. Therefore, the level of the sealing blocks 21 and 22 during top sealing may be the same as the level of the suction nozzles 101 and 102. In other words, the level of the sealing blocks 21 and 22 in the sealing area 30 during top sealing may be the same as the level of the suction nozzles 101 and 102 in the adhesion area 40. For this reason, the vertical movement of the sealing blocks 21 and 22 and the vertical movement of the suction nozzles 101 and 102 during top sealing can be coordinated with each other.

[0110] When heat fusion begins through the sealing blocks 21 and 22, the sealing blocks 21 and 22 move a predetermined distance further, pressurizing the pouches 11 and 12. At this time, the suction nozzles 101 and 102 can move a predetermined distance in the direction opposite to that of the sealing blocks 21 and 22, in order to adsorb the pouches 11 and 12 and form the upper and lower gap 13. In other words, it is preferable that as heat fusion progresses, the suction nozzles 101 and 102 move in the direction to adsorb the pouches 11 and 12 and form the upper and lower gap 13.

[0111] After thermal fusion begins, a predetermined amount of time may be required for the insulating material to melt and move to the adhesion region 40. Therefore, the upper and lower gaps 13 will be formed through the suction nozzles 101 and 102 before the predetermined time. After the upper and lower gaps 13 are formed, if the molten insulating material flows into the adhesion region 40, the molten insulating material may be separated into upper and lower parts by gravity and surface tension. In other words, the formation of an adhesion portion in the adhesion region 40 may be prevented.

[0112] In this embodiment, the upper and lower gap 13 may be formed on the left and right sides of the lead region 55 rather than in the lead region 55 itself. That is, it is preferable that the upper and lower gap 13 be formed only in the region where the upper pouch 11 and the lower pouch 12 are directly heat-fused together by the top sealing.

[0113] A protective tape or insulating film 90 is interposed in the lead region 55. That is, the insulating film 90 is attached to the upper and lower surfaces of the leads 80a and 80b to protect them and provide insulation. If adsorption is performed through the suction nozzles 101 and 102 in the lead region 55, the adhesion between the leads and the insulating film may be damaged, reducing the insulation performance. Therefore, it is preferable that the upper and lower gap 13 caused by adsorption is eliminated in the lead region 55.

[0114] Through the embodiments described above, the formation of adhesion in the top seal can be eliminated through the vertical gap in the adhesion region. Of course, the formation of adhesion can also be eliminated through the vertical gap in the side seal. [Industrial applicability]

[0115] This is described in the detailed description of the invention.

Claims

1. A forming step in which a portion of the pouch is indented to create a housing where the electrode assembly will be installed; Insertion step of installing the electrode assembly into the housing; and The sealing step includes applying pressure to a sealing area located outside the storage area and at a predetermined distance from the edge of the storage area to form a sealing portion between the stacked upper pouch and lower pouch, A method for manufacturing a pouch-type secondary battery, wherein at least a portion of the sealing step is performed while an upper and lower gap is maintained between the stacked pouches in an adhesion region located between the edge of the housing and the sealing region.

2. A method for manufacturing a pouch-type secondary battery according to claim 1, comprising a suction step of drawing the upper pouch upward and the lower pouch downward through a suction nozzle in the adhesion area in order to form and maintain the upper and lower gap.

3. The method for manufacturing a pouch-type secondary battery according to claim 2, wherein the suction step is performed after pressurization has begun through the sealing block in the sealing step.

4. The method for manufacturing a pouch-type secondary battery according to claim 3, wherein the suction step is performed until the pressurization is completed.

5. The method for manufacturing a pouch-type secondary battery according to claim 3, wherein the suction step is performed for a predetermined time after the pressurization is completed.

6. The method for manufacturing a pouch-type secondary battery according to claim 2, wherein the suction step through the suction nozzle is eliminated in the lead region of the pouch to which the leads of the electrode assembly are attached.

7. The method for manufacturing a pouch-type secondary battery according to claim 6, wherein the suction step is performed in the adhesion regions located on both sides of the lead region.

8. The method for manufacturing a pouch-type secondary battery according to claim 1, wherein the upper and lower gap is formed by a stepped portion that is formed in the adhesion region with a recess depth lower than that of the housing portion and has a step difference with respect to the housing portion.

9. A method for manufacturing a pouch-type secondary battery according to claim 8, wherein the stepped portion is formed together with the housing portion during the forming stage.

10. A method for manufacturing a pouch-type secondary battery according to claim 9, wherein the housing portion and the stepped portion are formed simultaneously in the forming stage.

11. The method for manufacturing a pouch-type secondary battery according to claim 8, wherein the stepped portion is formed in the lead region of the pouch to which the leads of the electrode assembly are attached.

12. The method for manufacturing a pouch-type secondary battery according to claim 8, wherein the stepped portion is formed in the attachment regions located on both sides of the lead region of the pouch to which the leads of the electrode assembly are attached.

13. A pouch case having a metal layer, with insulating coating layers formed on the bottom and top surfaces, and a housing area in which a portion is recessed; and The electrode assembly includes a lead that is exposed to the outside of the pouch case when the sealing area of ​​the stacked pouch cases is pressed and heat-sealed, and the sealing area is formed by heat fusion. A pouch-type secondary battery, wherein, when the sealing portion is formed, the formation of the sealing portion is limited in the adhesion region located between the edge of the housing portion and the sealing region by the upper and lower gap formed between the stacked pouch cases.

14. The pouch-type secondary battery according to claim 13, wherein the upper and lower gaps are formed by sucking the upper pouch case upward and the lower pouch case downward through the suction nozzle in the adhesion area.

15. The pouch-type secondary battery according to claim 14, wherein suction through the suction nozzle is prevented in the lead region of the pouch case to which the lead is attached.

16. The pouch-type secondary battery according to claim 15, wherein suction is performed through the suction nozzle in the attachment regions located on both sides of the lead region.

17. The pouch-type secondary battery according to claim 13, wherein the upper and lower gaps are formed by a stepped portion that is formed in the adhesion region with a recess depth lower than that of the housing portion and has a step difference with respect to the housing portion.

18. The pouch-type secondary battery according to claim 17, wherein the stepped portion is provided in the lead region of the pouch case to which the leads of the electrode assembly are attached.

19. The pouch-type secondary battery according to claim 17, wherein the stepped portion is formed in the attachment regions located on both sides of the lead region of the pouch case to which the leads of the electrode assembly are attached.

20. The pouch-type secondary battery according to claim 17, wherein the formation of the stepped portion is eliminated in the lead region of the pouch case to which the leads of the electrode assembly are attached.

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