Pouch-type battery case, method for manufacturing same, and method for manufacturing secondary

Abstract

A pouch-type battery case according to an embodiment of the present invention may comprise: a cup portion having a recessed shape; and an airbag portion provided on one side of the cup portion and having a recessed shape. A wrinkle portion may be formed on a peripheral portion of the airbag portion, the wrinkle portion being folded or unfolded according to an internal pressure of the airbag portion such that a depth of the airbag portion varies. The wrinkle portion may include: a protruding portion protruding toward an outer side of the airbag portion; and concave portions provided alternately with the convex portions in the depth direction of the airbag portion. A remaining thickness of the convex portion may be less than a remaining thickness of the concave portion.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2022-0108708, filed on August 29, 2022, which is hereby incorporated by reference in its entirety.

[0004] The present invention relates to a pouch-type battery case, a method of manufacturing the pouch-type battery case, and a method of manufacturing a secondary battery including the pouch-type battery case. Background Art

[0005] Generally, unlike non-rechargeable primary batteries, secondary batteries are chargeable and dischargeable, and are widely used in electronic devices such as mobile phones, notebook computers, camcorders, etc., electric vehicles, etc. In particular, since lithium secondary batteries have a larger capacity than nickel-cadmium batteries or nickel-metal hydride batteries and have a higher energy density per unit weight, their application range is rapidly increasing.

[0006] Secondary batteries may be classified according to the type of battery case, and representative examples of the secondary batteries may include a can-type secondary battery having a cylindrical or prismatic battery case, and a pouch-type secondary battery having a pouch-type battery case.

[0007] This pouch-type battery case may be provided with a cup portion for accommodating the electrode assembly and an air pocket portion for collecting gas. Like the cup portion for accommodating the electrode assembly, the air pocket portion may be deep drawn using a forming device.

[0008] In more detail, the method of manufacturing a pouch-type secondary battery may include: a process of sealing a portion of a pouch-type battery case in a state where the electrode assembly is accommodated in the cup portion; a process of injecting electrolyte through an unsealed opening of the pouch-type battery case; and a process of activating the electrode assembly by charging and discharging. In addition, gas generated in the activation process may be collected in the gas pocket portion.

[0009] In order to prevent unnecessary gas or air from remaining in the pouch type battery case, a process of sealing the opening may generally be performed in a negative pressure chamber (eg, a vacuum chamber).

[0010] However, unlike the cup portion that accommodates the electrode assembly, the air pocket portion may not maintain its shape due to negative pressure and may wrinkle or deform. When the air pocket portion is twisted or deformed, the volume of the air pocket portion is reduced, so there is a problem that the gas cannot be fully collected, and thus improvement is needed. Summary of the invention

[0011] Technical issues

[0012] An object of the present invention to solve the above problems is to provide a pouch type battery case capable of preventing an air pocket portion from wrinkling by providing a wrinkle portion on the air pocket portion and capable of sufficiently collecting a large amount of gas, and a method of manufacturing the same.

[0013] Another object to be achieved by the present invention is to provide a method of manufacturing a secondary battery including the pouch-type battery case.

[0014] Technical Solution

[0015] A pouch-type battery case according to an embodiment of the present invention may include: a cup portion having a concave shape; and an air pocket portion provided at one side of the cup portion and having a concave shape. A wrinkle portion may be formed on a peripheral portion of the air pocket portion, and the wrinkle portion is folded or unfolded according to the internal pressure of the air pocket portion so that the depth of the air pocket portion varies. The wrinkle portion may include: a convex portion protruding toward the outside of the air pocket portion; and a concave portion alternately provided with the convex portion in the depth direction of the air pocket portion. The remaining thickness of the convex portion may be smaller than the remaining thickness of the concave portion.

[0016] The depth of the air pocket portion may vary between a contracted depth and an expanded depth greater than the contracted depth, and wherein the expanded depth may be 0.7 to 1.3 times the depth of the cup portion.

[0017] The depth of the air pocket portion may vary between a contracted depth and an expanded depth greater than the contracted depth, and wherein the expanded depth may be more than 12 times the contracted depth.

[0018] The method for manufacturing a pouch-type battery case according to an embodiment of the present invention may include: a process of forming a cup portion and an air pocket portion in a pouch sheet; and a process of forming a wrinkle portion on a peripheral portion of the air pocket portion, the wrinkle portion folding or unfolding according to the internal pressure of the air pocket portion so that the depth of the air pocket portion changes. The wrinkle portion may include: a convex portion protruding toward the outside of the air pocket portion; and a concave portion alternately arranged with the convex portion in the depth direction of the air pocket portion. The remaining thickness of the convex portion may be less than the remaining thickness of the concave portion.

[0019] The air pocket portion on which the wrinkle portion is formed may have an initial depth, and the depth of the air pocket portion may be varied between a contraction depth smaller than the initial depth and an expansion depth larger than the initial depth.

[0020] The contraction depth may be less than or equal to 0.1 times the initial depth.

[0021] The expansion depth may be 1.2 to 1.3 times the initial depth.

[0022] The device for forming the wrinkle portion may include: a plurality of support portions contacting the periphery of the air pocket portion and arranged at predetermined intervals in a depth direction of the air pocket portion; and a negative pressure portion configured to apply negative pressure to the periphery of the air pocket portion through gaps between the plurality of support portions.

[0023] The method for manufacturing a secondary battery according to an embodiment of the present invention may include: a process of preparing a pouch-type battery case; a process of accommodating an electrode assembly and an electrolyte in a cup portion of the pouch-type battery case; a process of sealing the pouch-type battery case in a negative pressure chamber; and a process of collecting gas generated by charging and discharging the electrode assembly into an air pocket portion of the pouch-type battery case. The process of preparing the pouch-type battery case may include: a process of forming the cup portion and the air pocket portion in a bag sheet; and a process of forming a wrinkle portion on a peripheral portion of the air pocket portion, the wrinkle portion folding or unfolding according to the internal pressure of the air pocket portion so that the depth of the air pocket portion changes. The wrinkle portion may include: a convex portion protruding toward the outside of the air pocket portion; and a concave portion alternately arranged with the convex portion in the depth direction of the air pocket portion. The remaining thickness of the convex portion may be smaller than the remaining thickness of the concave portion.

[0024] In the process of preparing the pouch type battery case, the air pocket portion may be formed to an initial depth, and in the process of sealing the pouch type battery case, the depth of the air pocket portion may be changed to a contraction depth smaller than the initial depth.

[0025] In the step of collecting the gas in the air pocket portion, the depth of the air pocket portion may be changed to an expanded depth greater than the initial depth.

[0026] Beneficial Effects

[0027] According to the preferred embodiment of the present invention, even if negative pressure is applied to the air pocket when the pouch type battery case is sealed, the wrinkled portion is contracted and the depth of the air pocket can be reduced. Therefore, the air pocket can be prevented from wrinkling.

[0028] In addition, when the gas is collected in the air pocket portion, the internal pressure of the air pocket portion can be increased, so the wrinkle portion can be expanded and the depth of the air pocket portion can be increased. As a result, the air pocket portion can stably collect a sufficiently large amount of gas.

[0029] Furthermore, effects that are obvious to those skilled in the art can be expected from the configuration according to the embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The following drawings attached to the present application illustrate preferred embodiments of the present invention and may be used to further understand the technical spirit of the present invention together with the detailed description of the present invention, and thus the present invention should not be construed as being limited to the drawings.

[0031] Figure 1 is an assembly view illustrating a pouch-type battery case and an electrode assembly accommodated therein according to an embodiment of the present invention.

[0032] Figure 2 is a perspective view illustrating a state when a pouch type battery case according to an embodiment of the present invention is viewed in another direction.

[0033] Figure 3 FIG. 1 is a side view of a pouch-type battery case according to an embodiment of the present invention.

[0034] Figure 4 It is a graphic Figure 3 Schematic diagram of a state where the air bag portion is contracted.

[0035] Figure 5 It is a graphic Figure 3 Schematic diagram of the state in which the air bag portion is expanded.

[0036] Figure 6 is a schematic diagram illustrating an apparatus for forming wrinkle portions according to an embodiment of the present invention.

[0037] Figure 7 is a flowchart illustrating a method of manufacturing a secondary battery according to another embodiment of the present invention.

[0038] Figures 8a to 8d are schematic diagrams sequentially illustrating a method of manufacturing a secondary battery according to another embodiment of the present invention. DETAILED DESCRIPTION

[0039] Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. However, the present invention can be implemented in many different forms and should not be limited or interpreted as being limited to the following examples.

[0040] In order to explain the present invention clearly, the detailed description of the parts irrelevant to the description or the related known technologies that may unnecessarily obscure the subject matter of the present invention is omitted, and in this specification, reference marks are added to the components in each accompanying drawing. In this case, the same or similar reference marks refer to the same or similar elements throughout the specification.

[0041] Furthermore, the terms or words used in the specification and claims should not be restrictively interpreted as ordinary meanings or dictionary-based meanings, but should be interpreted as meanings and concepts consistent with the scope of the present invention based on the principle that the inventor can appropriately define the concepts of the terms to best describe his or her invention.

[0042] Figure 1is an assembly view illustrating a pouch-type battery case and an electrode assembly accommodated therein according to an embodiment of the present invention.

[0043] The pouch-type battery case 100 (hereinafter referred to as "battery case") according to an embodiment of the present invention may be manufactured by shaping the pouch sheet 137. The pouch sheet 137 may be a sheet-type member laminated with a plurality of layers. For example, the pouch sheet 137 may include a first resin layer (e.g., a polypropylene material) defining one surface thereof, a second resin layer (e.g., a polyethylene terephthalate material) defining the other surface thereof, and a metal layer (e.g., made of aluminum) disposed between the first resin layer and the second resin layer. The pouch sheet 137 may have flexibility and formability.

[0044] The battery case 100 may include a cup portion 110 having a concave shape and an air pocket portion 120 disposed at one side of the cup portion 110 and having a concave shape. The battery case 100 may further include a platform portion 130 disposed around the cup portion 110 and the air pocket portion 120.

[0045] In more detail, the battery housing 100 may include a first housing 101 and a second housing 102. Figure 1 As shown in , a case where the first shell 101 and the second shell 102 are integrally connected to each other will be described as an example. The first shell 101 and the second shell 102 may be divided by the folding portion 140. When the folding portion 140 is folded, the first shell 101 and the second shell 102 may face each other. However, not limited to this, the first shell 101 and the second shell 102 may also be manufactured separately so that the first shell 101 and the second shell 102 are separated from each other.

[0046] At least one of the first shell 101 and the second shell 102 may include a cup portion 110. In addition, at least one of the first shell 101 and the second shell 102 may include an air bag portion 120. Figure 1 As shown in the figure, the case where the first shell 101 includes the cup portion 110 and the air bag portion 120, and the second shell 102 does not include the cup portion 110 and the air bag portion 120 will be described as an example. Those skilled in the art will be able to easily understand the implementation in which each of the first shell 101 and the second shell 102 includes the cup portion 110 and the air bag portion 120.

[0047] The cup portion 110 may be recessed from the platform portion 130 by a predetermined depth to define a space for accommodating the electrode assembly 200. After the electrode assembly 200 is accommodated in the cup portion 110, the folding portion 140 may be folded. As a result, the second case 102 may cover the electrode assembly 200 accommodated in the cup portion 110. Thus, the electrode assembly 200 may be accommodated in the cup portion 110.

[0048] The air pocket portion 120 may be recessed in the same direction as the cup portion 110. The air pocket portion 120 may define a space in which gas is collected.

[0049] The air pocket portion 120 may be disposed at one side of the cup portion 110. In more detail, the air pocket portion 120 may be disposed at an opposite side of the folding portion 140 with respect to the cup portion.

[0050] The airbag portion 120 may be provided with a corrugated portion 121 formed on the peripheral portion thereof, and the corrugated portion 121 may be folded or unfolded according to the internal pressure of the airbag portion 120 so that the depth of the airbag portion 120 may be varied. The corrugated portion 121 may have a bellows shape. In more detail, the convex portion 122 may be repeatedly formed in the depth direction of the airbag portion 120 (see FIG. Figure 3 ) and recesses 123 to provide the wrinkled portion 121.

[0051] The electrode assembly 200 may be provided with a separator interposed between a plurality of electrodes. For example, the electrode assembly 200 may be a simple stack type in which a plurality of electrodes and separators are alternately stacked or a lamination & stack type in which unit cells laminated with electrodes and separators are stacked, and the electrode assembly 200 may have a jelly roll type in which an electrode sheet and a separator sheet are wound together, a stack & folding type in which a separator sheet stacked with unit cells is folded, or a z-folding type in which a separator sheet stacked with a plurality of electrodes is folded in a zigzag shape.

[0052] The electrode assembly 200 may be provided with an electrode tab 210. The electrode tab 210 may protrude outward from the electrode of the electrode assembly 200. In more detail, a plurality of positive electrode tabs 211 connected to a plurality of positive electrodes and a plurality of negative electrode tabs 212 connected to a plurality of negative electrodes may protrude in different directions (e.g., opposite directions) relative to the electrode assembly 200. However, not limited thereto, the positive electrode tab 211 and the negative electrode tab 212 may protrude in directions parallel to each other.

[0053] The electrode lead 220 may be connected to the plurality of electrode tabs 210 . In more detail, the positive electrode lead 221 may be connected to the plurality of positive electrode tabs 211 , and the negative electrode lead 222 may be connected to the plurality of negative electrode tabs 212 .

[0054] One end of the electrode lead 220 may be connected to the plurality of electrode tabs 210 and the other end may protrude to the outside of the battery case 100 .

[0055] A portion of the electrode lead 220 may be surrounded by the insulating portion 230. For example, the insulating portion 230 may include an insulating tape. When the electrode assembly 200 is accommodated in the cup portion 110, the insulating portion 230 may be provided to correspond to the platform portion 130 of the battery case 100. When the battery case 100 is sealed, the insulating portion 230 may be thermally fused to the platform portion 130. Thus, the insulating portion 230 may insulate the electrode lead 220 from the battery case 100 to maintain the sealing of the battery case 100.

[0056] Figure 2 is a perspective view illustrating a state when a pouch-type battery case according to an embodiment of the present invention is viewed in another direction, Figure 3 is a side view of a pouch-type battery case according to an embodiment of the present invention, Figure 4 It is a graphic Figure 3 A diagram showing a state in which the air bag portion is contracted. Figure 5 It is a graphic Figure 3 Schematic diagram of the state in which the air bag portion is expanded.

[0057] For ease of explanation, Figures 2 to 5 It is shown in Figure 1 The first housing 101 is shown in FIG.

[0058] The depth of the air pocket portion 120 may be varied by the wrinkled portion 121 provided on the air pocket portion 120 .

[0059] As described above, the corrugated portion 121 may have a bellows shape. In more detail, the corrugated portion 121 may include convex portions 122 protruding toward the outside of the air pocket portion 120 and concave portions 123 alternately disposed with the convex portions 122 in the depth direction of the air pocket portion 120 .

[0060] The convex portion 122 may be formed to be convex toward the outside of the airbag portion 120 , and the concave portion 123 may be provided to be concave toward the inside of the airbag portion 120 .

[0061] The remaining thickness t1 of the convex portion 122 may be smaller than the remaining thickness t2 of the concave portion 123. In more detail, the remaining thickness t1 of the outermost portion of the convex portion 122 may be smaller than the remaining thickness t2 of the innermost portion of the concave portion 123. This may be a feature that occurs when negative pressure is applied to the outer side of the peripheral portion of the airbag portion 120 to form the wrinkle portion 121. Figure 6 Describe in detail.

[0062] The air pocket portion 120 may be formed with an initial depth d1. The initial depth d1 may be less than the depth d of the cup portion 110. The initial depth d1 may refer to a depth after the wrinkle portion 121 is formed in the air pocket portion 120.

[0063] The depth of the air pocket portion 120 may be changed by the wrinkled portion 121. In more detail, when the wrinkled portion 121 contracts, the depth of the air pocket portion 120 may decrease. The wrinkled portion 121 contraction may refer to a decrease in the pitch p between the plurality of convex portions 122. On the other hand, when the wrinkled portion 121 expands, the depth of the air pocket portion 120 may increase. The wrinkled portion 121 expansion may refer to an increase in the pitch p between the plurality of convex portions 122.

[0064] The depth of the air pocket portion 120 may vary between a contraction depth d2 and an expansion depth d3. The depth of the air pocket portion 120 may vary within a range in which the wrinkle portion 121 is not excessively deformed and the function of the wrinkle portion 121 is maintained.

[0065] like Figure 4 As shown in , when the wrinkled portion 121 is maximally contracted, the air pocket portion 120 may have a contracted depth d2. For example, when the battery case 100 is sealed in a negative pressure chamber, the wrinkled portion 121 may contract so that the air pocket portion 120 has a contracted depth d2.

[0066] The contraction depth d2 may be less than the initial depth d1. In more detail, the contraction depth d2 may be less than 0.1 times the initial depth d1. If the contraction depth d2 is greater than 0.1 times the initial depth d1, the wrinkle portion 121 may not be sufficiently deformed when the battery case 100 is sealed in the negative pressure chamber, and the air pocket portion 120 may wrinkle.

[0067] like Figure 5 As shown in , when the wrinkle portion 121 is maximally expanded, the air pocket portion 120 may have an expanded depth d3. For example, during an activation process in which the electrode assembly 200 is charged and discharged in a state in which the battery case 100 is sealed, the wrinkle portion 121 may expand due to the internal pressure of the gas generated by the activation process, so that the air pocket portion 120 has an expanded depth d3.

[0068] The expansion depth d3 may be greater than the contraction depth d1. The expansion depth d3 may be greater than the initial depth d1. In more detail, the expansion depth d3 may be 1.2 to 1.3 times the initial depth d1. That is, the expansion depth d3 may be more than 12 times the contraction depth d2. If the expansion depth d3 is less than 1.2 times the initial depth d1, there is a risk that the wrinkle portion 121 may not be sufficiently deformed and the gas may not be sufficiently collected in the air pocket portion 120. On the other hand, if the expansion depth d3 is greater than 1.3 times the initial depth d1, cracks may occur due to excessive stretching of the peripheral portion of the air pocket portion 120 when the wrinkle portion 121 is formed, or the air pocket portion 120 may rupture due to the internal pressure of the collected gas.

[0069] In addition, the expansion depth d3 of the air pocket portion 120 may be 0.7 to 1.3 times the depth d of the cup portion 110. If the expansion depth d3 is less than 0.7 times the depth d of the cup portion 110, there is a risk that the gas may not be sufficiently collected in the air pocket portion 120. On the contrary, if the expansion depth d3 is greater than 1.3 times the depth d of the cup portion 110, the volume of the air pocket portion 120 may become unnecessarily large, and when the air pocket portion 120 is formed, the bag sheet 137 may be overstretched to generate cracks.

[0070] Thus, the wrinkled portion 121 may prevent the air pocket portion 120 from wrinkling due to negative pressure, and may increase the amount of gas collected by the air pocket portion 120, thereby improving stability in the activation process.

[0071] Figure 6 is a schematic diagram illustrating an apparatus for forming wrinkle portions according to an embodiment of the present invention.

[0072] Figure 6 The diagram shows the formation of the wrinkle portion 121 (see Figure 3 ) before the air bag portion 120. The device 10 for forming the wrinkle portion 121 on the peripheral portion of the air bag portion 120 (hereinafter referred to as the wrinkle forming device) can apply negative pressure to the outer side of the peripheral portion of the air bag portion 120 to form the wrinkle portion 121.

[0073] In more detail, the wrinkle forming device 10 may include: a plurality of support portions 11 that are in contact with the periphery of the air bag portion 120 and are arranged at predetermined intervals in the depth direction of the air bag portion 120, and a negative pressure portion 12 that applies negative pressure to the periphery of the air bag portion 120 through the gaps g between the plurality of support portions 11.

[0074] Each of the plurality of support portions 11 may surround the outer circumference of the airbag portion 120. The plurality of support portions 11 may contact the outer circumference of the airbag portion 120 at predetermined intervals in the depth direction of the airbag portion 120. When the negative pressure portion 12 applies negative pressure to the outer circumference of the airbag portion 120, each of the plurality of support portions 11 may support the outer circumference of the airbag portion 120.

[0075] In order to prevent cracks from being generated in the airbag portion 120 , the inner end of the support portion 122 may be rounded.

[0076] The negative pressure portion 12 can apply negative pressure to the outer periphery of the air bag portion 120 through the gaps g between the plurality of support portions 11. Figure 6 As shown in , the plurality of gaps g may be in communication with the negative pressure chamber, and the negative pressure portion 12 may apply negative pressure to the negative pressure chamber. For example, the negative pressure portion 12 may include a negative pressure pump.

[0077] Thus, the portion of the peripheral portion of the air bag portion 120 facing the gap g can be stretched outward by negative pressure. The portion of the peripheral portion of the air bag portion 120 facing the gap g can be stretched to form the convex portion 122 (see FIG. Figure 3 ), and the portion in contact with the support portion 11 may form a recess 123.

[0078] As described above, since a portion of the peripheral portion of the air bag portion 120 is stretched outward to form the convex portion 122, Figure 3 As shown in , the remaining thickness t1 of the convex portion 122 may be smaller than the remaining thickness t2 of the concave portion 123 .

[0079] The wrinkle portion 121 can be easily and quickly formed by the wrinkle forming device 10.

[0080] Figure 7 is a flowchart illustrating a method of manufacturing a secondary battery according to another embodiment of the present invention, Figures 8a to 8d are schematic diagrams sequentially illustrating a method of manufacturing a secondary battery according to another embodiment of the present invention.

[0081] A method of manufacturing a secondary battery according to another embodiment of the present invention may be a method of manufacturing a secondary battery including the battery case 100 described above.

[0082] The method for manufacturing a secondary battery may include: a process of preparing a battery case 100 (S10) (hereinafter referred to as a "case preparation process"), a process of accommodating an electrode assembly 200 and an electrolyte in a cup portion 110 (S20) (hereinafter referred to as a "accommodation process"), a process of sealing the battery case 100 in a negative pressure chamber (S30) (hereinafter referred to as a "sealing process"), and a process of collecting gas generated by charging and discharging the electrode assembly 200 into an air bag portion 120 (S40) (hereinafter referred to as a "gas collection process").

[0083] The case preparation process ( S10 ) may be named “a method of manufacturing a pouch-type battery case” and itself may constitute another embodiment of the present invention.

[0084] In more detail, the shell preparation process (S10) may include: a process (S11) of forming the cup portion 110 and the air bag portion 120 in the bag sheet 137 (hereinafter referred to as the "first forming process"), and a process (S12) of forming the wrinkled portion 121 on the peripheral portion of the air bag portion 120 (hereinafter referred to as the "second forming process"), wherein the wrinkled portion 121 is folded or unfolded according to the internal pressure of the air bag portion 120 so that the depth of the air bag portion 120 can be changed.

[0085] In the first forming process (S11), each of the cup portion 110 and the air pocket portion 120 may be formed to have a concave shape in the bag sheet 137. For example, the cup portion 110 and the air pocket portion 120 may be formed by deep drawing. The air pocket portion 120 and the cup portion 110 may be formed simultaneously or may be formed sequentially according to a preset order.

[0086] In the second forming step (S12), the wrinkle forming device 10 (see Figure 6 ) can apply negative pressure to the periphery of the air bag portion 120 to form the wrinkled portion 121. Since it has been explained above, the detailed content will be omitted.

[0087] The air pocket portion 120 formed with the wrinkle portion 121 may have an initial depth d1. That is, in the case preparation process (S10), the air pocket portion 120 may be formed to have an initial depth d1.

[0088] In the housing process ( S20 ), the folding portion 140 may be folded in a state where the electrode assembly 200 is housed in the cup portion 110 so that the first case 101 and the second case 102 face each other.

[0089] Afterwards, if Figure 8a As shown in , some portions of the platform portion 130 of the first shell 101 and the second shell 102 that contact each other may be thermally fused to form a first sealing portion 161. In a state where the folded portion 140 faces downward, the first sealing portion 161 may be formed along both edges of the battery shell 100. In addition, the edge of each of the first shell 101 and the second shell 102 opposite to the folded portion 140 may not be sealed to form the opening 150.

[0090] Thereafter, electrolyte may be injected through the opening 150. The electrolyte may enter the cup portion 110, thereby impregnating the electrode assembly 200.

[0091] In the sealing step (S30), if Figure 8b As shown in , the opening 150 may be sealed to form a second sealing portion 162 connected to the previously formed first sealing portion 161. As a result, the battery case 100 may be completely sealed.

[0092] The sealing process (S30) may be performed in a state where the battery case 100 is disposed in a negative pressure chamber (not shown) (eg, a vacuum chamber). As a result, the battery case 100 may be sealed in a state where any gas or air remaining in the battery case 100 is removed.

[0093] In the sealing step (S30), the depth of the air pocket portion 120 may be reduced to a contraction depth d2 (see FIG. Figure 4That is, as negative pressure is applied in the air pocket portion 120 through the negative pressure chamber, the wrinkled portion 121 may shrink, and thus the depth of the air pocket portion 120 gradually decreases. As a result, the air pocket portion 120 may be prevented from wrinkling.

[0094] As described above, the contraction depth d2 may be 0.1 times or less of the initial depth d1.

[0095] After the battery case 100 is sealed, the electrode assembly 200 may be activated by charging and discharging the electrode assembly 200 through the electrode lead 210 protruding to the outside of the battery case 100 .

[0096] In the gas collection step (S40), if Figure 8b As shown in , gas generated by activation of the electrode assembly 200 may be collected in the air pocket portion 120 .

[0097] In the gas collecting process (S40), the depth of the air pocket 120 may become an expanded depth d3 greater than the initial depth d1. That is, as the internal pressure of the air pocket 120 increases due to the collected gas, the wrinkle portion 121 may expand and the depth of the air pocket 120 may increase. As a result, the air pocket 120 may stably collect a sufficiently large amount of gas.

[0098] As described above, the expansion depth d3 may be 1.2 to 1.3 times the initial depth d1.

[0099] The method of manufacturing a secondary battery may further include a process of exhausting gas from the air pocket portion 120 ( S50 ) (hereinafter referred to as a “degassing process”), and a process of further sealing the battery case 100 and cutting the air pocket portion 120 (hereinafter referred to as a “cutting process”).

[0100] In the degassing step (S50), Figure 8c As shown in FIG. 1 , at least one hole H may be formed by perforating the air pocket portion 120 or a portion covering the air pocket portion 120 , and gas in the battery case 100 may be discharged through the hole H.

[0101] The degassing process ( S50 ) may be performed while the battery case 100 is disposed in a negative pressure chamber (not shown) (eg, a vacuum chamber).

[0102] In the cutting process (S60), Figure 8d As shown in FIG. 1 , a portion between the cup portion 110 and the airbag portion 120 may be sealed to form a third sealing portion 163. Both ends of the third sealing portion 163 may be connected to the first sealing portion 161.

[0103] Thereafter, the battery case 100 may be cut along a virtual cutting line CL disposed on the third sealing portion 163 or disposed outside the third sealing portion 163. As a result, a portion of the battery case 100 including the air pocket portion 120 may be removed.

[0104] The above-disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments, which fall within the true spirit and scope of the present invention.

[0105] Therefore, the embodiments of the present invention should be considered as illustrative rather than restrictive, and the technical spirit of the present invention is not limited to the aforementioned embodiments.

[0106] Therefore, the scope of the disclosure is defined not by the detailed description of the invention but by the appended claims, and all differences within the scope will be construed as being included in the disclosure.

[0107] [Description of Reference Signs]

[0108] 10: Wrinkle forming device 11: Support part

[0109] 12: Negative pressure unit 100: Pouch type battery case

[0110] 101: first housing 102: second housing

[0111] 110: cup part 120: air bag part

[0112] 121: wrinkled part 122: convex part

[0113] 123: concave portion 130: platform portion

[0114] 140: Folding portion 200: Electrode assembly.

Claims

1. A pouch-type battery housing, comprising: a cup portion having a concave shape; and an air pocket portion provided at one side of the cup portion and having a concave shape, A wrinkle portion is formed on the peripheral portion of the air bag portion, and the wrinkle portion is folded or unfolded according to the internal pressure of the air bag portion so that the depth of the air bag portion changes. The wrinkle portion comprises: a convex portion protruding toward the outer side of the air bag portion; and In the depth direction of the air bag portion, there are recessed portions alternately arranged with the convex portions. The remaining thickness of the convex portion is smaller than the remaining thickness of the concave portion.

2. The pouch-type battery case according to claim 1, wherein the depth of the air pocket portion varies between a contraction depth and an expansion depth greater than the contraction depth, and The expansion depth is 0.7 to 1.3 times the depth of the cup portion.

3. The pouch-type battery case according to claim 1, wherein the depth of the air pocket portion varies between a contraction depth and an expansion depth greater than the contraction depth, and The expansion depth is more than 12 times the contraction depth.

4. A method for manufacturing a pouch-type battery case, the method comprising: The process of forming a cup portion and an air pocket portion in the bag sheet; as well as a step of forming a wrinkled portion on the peripheral portion of the air bag portion, wherein the wrinkled portion is folded or unfolded according to the internal pressure of the air bag portion so that the depth of the air bag portion changes, The wrinkle portion comprises: a convex portion protruding toward the outer side of the air bag portion; and In the depth direction of the air bag portion, there are recessed portions alternately arranged with the convex portions. The remaining thickness of the convex portion is smaller than the remaining thickness of the concave portion.

5. The method according to claim 4, wherein: The air pocket portion on which the wrinkled portion is formed has an initial depth, and The depth of the air pocket portion varies between a contraction depth that is less than the initial depth and an expansion depth that is greater than the initial depth. The method according to claim 5 , wherein the contraction depth is less than 0.1 times the initial depth. The method of claim 5 , wherein the expansion depth is 1.2 to 1.3 times the initial depth.

8. The method of claim 4, wherein the means for shaping the wrinkled portion comprises: a plurality of support portions contacting the outer periphery of the air pocket portion and arranged at predetermined intervals in a depth direction of the air pocket portion; as well as A negative pressure portion is configured to apply negative pressure to the outer periphery of the air bag portion through gaps between the plurality of support portions.

9. A method for manufacturing a secondary battery, the method comprising: A process for preparing a pouch-type battery casing; The process of accommodating an electrode assembly and an electrolyte in a cup portion of the pouch-type battery case; The step of sealing the pouch-type battery housing in a negative pressure chamber; as well as a step of collecting gas generated by charging and discharging the electrode assembly into an air pocket portion of the pouch-type battery case, The process of preparing the pouch-type battery housing includes: forming the cup portion and the air bag portion in the bag sheet; and a step of forming a wrinkled portion on the peripheral portion of the air bag portion, wherein the wrinkled portion is folded or unfolded according to the internal pressure of the air bag portion so that the depth of the air bag portion changes, The wrinkle portion comprises: a convex portion protruding toward the outside of the air bag portion; and In the depth direction of the air bag portion, there are recessed portions alternately arranged with the convex portions. The remaining thickness of the convex portion is smaller than the remaining thickness of the concave portion.

10. The method according to claim 9, wherein: In the process of preparing the pouch-type battery case, the air pocket portion is formed to an initial depth, and In the step of sealing the pouch-type battery case, the depth of the air pocket portion becomes a contraction depth smaller than the initial depth.

11. The method according to claim 10, wherein: In the step of collecting the gas in the air pocket portion, the depth of the air pocket portion becomes an expanded depth greater than the initial depth.

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