Method for manufacturing secondary batteries and pouch cells

Abstract

The present invention relates to a method for manufacturing a secondary battery and a pouch cell used therein, which can improve process efficiency by reducing the number of cases removed in the manufacturing process and reducing the space required in the manufacturing process. The pouch cell according to the present invention includes an electrode assembly, a gas removal member for removing gas generated in the electrode assembly, and a pair of cases that house the electrode assembly and the gas removal member inside, wherein at least one of the pair of cases includes a cup portion molded to accommodate the electrode assembly and a terrace portion forming the periphery of the cup portion, and the gas removal member can be placed on the terrace portion.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0056513 filed on April 28, 2023, and all the contents disclosed in the literature of the Korean patent application are incorporated herein by reference in their entirety.

[0002] The present invention relates to a method for manufacturing a secondary battery and a pouch cell, and more particularly, to a method for manufacturing a secondary battery capable of charging and discharging and a pouch cell used therefor.

Background Art

[0003] In recent years, due to the depletion of fossil fuels, the price of energy sources has increased, and the concern about environmental pollution has amplified. The need for environmentally friendly alternative energy sources has become an essential and indispensable factor for future life. Therefore, research on various power generation technologies such as solar power, wind power, and tidal power has continued, and there has also been a great deal of interest in power storage devices such as batteries for more efficiently using the electrical energy produced in this way.

[0004] Furthermore, as the technology development and demand for electronic mobile devices and electric vehicles using batteries increase, the demand for batteries as an energy source has increased rapidly. Along with this, many studies have been conducted on batteries that can meet various needs.

[0005] Batteries for storing electrical energy can generally be divided into primary batteries and secondary batteries. Primary batteries are disposable consumable batteries, while secondary batteries are rechargeable batteries manufactured using materials in which the oxidation and reduction processes between current and substances can be repeated. That is, when a reduction reaction is performed on the material by current, the power source is charged, and when an oxidation reaction is performed on the material, the power source discharges, and electricity is generated while such charging and discharging are repeated.

[0006] Rechargeable batteries can be classified into cylindrical cells, pouch cells, prismatic cells, etc., depending on their form. Among these, pouch cells can include electrode assemblies in which positive electrodes, negative electrodes, separators, etc., are stacked inside the pouch.

[0007] On the other hand, the manufacturing process of pouch-type cells may include a step to remove gases that accumulate inside the case. In this regard, pouch-type cells can undergo an activation step during the manufacturing process. Here, as the electrode assembly is repeatedly charged and discharged, gases may be generated inside the case, and the gas removal step can remove the gases inside the case. If gases inside the pouch are not removed during the manufacturing process of pouch-type cells, problems such as a decrease in the performance of the finished pouch-type cells may occur.

[0008] Conventional methods for manufacturing pouch-type rechargeable batteries involve collecting gas in a gas pocket formed around the cup portion where the electrode assembly is located in the case, and physically expelling the collected gas to the outside of the case through holes or the like, thereby removing gas from inside the case.

[0009] In this type of secondary battery manufacturing method, the size of the gas pocket gradually increases as a large amount of gas is generated. Therefore, a larger manufacturing space is required in proportion to the increased size of the gas pocket. Furthermore, since the process includes removing a portion of the gas pocket after the gas has been removed, the amount of material removed increases in proportion to the increased size of the gas pocket. In other words, both the cost and time used in the manufacturing process increase. Thus, conventional secondary battery manufacturing methods have problems with reduced process efficiency due to decreased economic efficiency and space utilization.

[0010] Therefore, when a large amount of gas is generated during the manufacturing process, there is a need for a secondary battery manufacturing method and a pouch cell used therein that can improve the efficiency of the process. [Overview of the Initiative] [Problems that the invention aims to solve]

[0011] The object of the present invention is to provide a method for manufacturing a secondary battery and a pouch cell used therein that can improve process efficiency by reducing the number of cases removed during the manufacturing process and reducing the space required for the manufacturing process. [Means for solving the problem]

[0012] The pouch cell according to the present invention includes an electrode assembly, a gas removal member for removing gas generated in the electrode assembly, and a pair of cases for housing the electrode assembly and the gas removal member, wherein at least one of the pair of cases includes a cup portion molded to accommodate the electrode assembly and a terrace portion forming the periphery of the cup portion, and the gas removal member can be disposed on the terrace portion.

[0013] The gas removal member may be equipped with a gas absorbent that can absorb gas through a chemical reaction.

[0014] The gas removal member further comprises an outer casing containing a porous material, and the gas absorbent can be housed inside the outer casing.

[0015] The gas absorbent may contain NaOH or Ca(OH)2 to remove CO2 generated in the electrode assembly.

[0016] The gas absorbent may include a substance that removes at least one of O2, C2H4, C2H6, and CO generated in the electrode assembly.

[0017] The terrace portion may include an electrolyte injection portion, which is positioned at one end so as to be spaced apart from the gas removal member.

[0018] The pair of cases are arranged facing each other, and a gas pocket is formed between the opposing terrace portions, where gas generated by the electrode assembly is collected. The gas removal member can be placed in the gas pocket.

[0019] The gas removal member can be disposed eccentrically in the gas pocket portion.

[0020] The method for manufacturing a secondary battery according to the present invention includes: (a) a step of accommodating an electrode assembly in a cup portion formed in a case; (b) a step of disposing a gas removal member inside the case; (c) a step of charging and discharging the electrode assembly to activate it; and (d) a step of cutting along a cut portion of the case so that a part of the case including the gas removal member is removed.

[0021] The method for manufacturing a secondary battery can further include a step of sealing the cut portion of the case before the step (d).

[0022] In the step (b), the gas removal member can be disposed so as to have a gap from the cup portion.

[0023] In the step (b), the gas removal member can be disposed so as to adhere to the inside of the case. [Advantages of the Invention]

[0024] According to a preferred embodiment of the present invention, the space required for the manufacturing process of the secondary battery can be reduced, and the space utilization can be improved.

[0025] Also, the volume of the case required in the manufacturing process of the secondary battery can be reduced, and the amount of the case to be removed can be decreased.

[0026] In addition, the gas inside the case can be removed more efficiently in the manufacturing process of the secondary battery.

[0027] Thereby, the time and cost used in the manufacturing process of the secondary battery can be reduced, and the efficiency of the process can be improved.

[0028] In addition, it can include effects that can be easily predicted by those skilled in the art from the configuration according to the preferred embodiment of the present invention.

[0029] The following drawings attached to this specification illustrate the preferred embodiments of the present invention and serve to further understand the technical idea of the present invention together with the detailed description of the invention to be described later. The present invention should not be construed as being limited only to the matters described in such drawings.

Brief Description of the Drawings

[0030] [Figure 1] It is a perspective view schematically showing a pouch cell according to an embodiment of the present invention. [Figure 2] It is a plan view schematically showing a pouch cell according to an embodiment of the present invention. [Figure 3] It is an exploded perspective view schematically showing a pouch cell according to an embodiment of the present invention. [Figure 4] It is a flowchart schematically showing a method for manufacturing a secondary battery according to another embodiment of the present invention.

Modes for Carrying Out the Invention

[0031] Hereinafter, referring to the attached drawings, the preferred embodiments of the present invention will be described in detail so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement it. However, the present invention can be realized in various different forms and is not limited or restricted by the following embodiments.

[0032] To clearly explain the present invention, a detailed description of parts not related to the explanation or related known technologies that may obscure the gist of the present invention is omitted. In this specification, when assigning reference numerals to the components of each drawing, the same or similar reference numerals are assigned to the same or similar components throughout the specification.

[0033] Furthermore, the terms and words used in this specification and in the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather should be interpreted in a manner consistent with the technical idea of ​​the present invention, in accordance with the principle that inventors may define the concepts of terms as appropriate to best describe their invention.

[0034] Pouch Cell Figure 1 is a schematic perspective view illustrating a pouch cell 10 according to one embodiment of the present invention, and Figure 2 is a schematic plan view illustrating a pouch cell 10 according to one embodiment of the present invention.

[0035] A pouch cell 10 according to one embodiment of the present invention may include a case 100, where the case 100 may consist of a pair. Specifically, the case 100 may include a first case 101 and a second case 102 that are joined together facing each other.

[0036] For example, case 100 has a form in which a pair is connected to each other, and can be folded based on the connected part. Here, the first case 101 and the second case 102 have a form in which they are connected to each other, and can be joined to each other while being folded.

[0037] As another example, the pair of cases 100 can be joined together so that they face each other while remaining separate. Here, the first case 101 and the second case 102 can each be configured independently.

[0038] Case 100 of the pouch cell 10 according to one embodiment of the present invention is a state in which the first case 101 and the second case 102 are joined together, and any of the configurations described above as examples are possible.

[0039] The pouch cell 10 may further include an electrode assembly 300 housed inside the case 100. Here, the electrode assembly 300 may include a positive electrode, a negative electrode, and a separator. Specifically, the electrode assembly 300 may have a jelly roll form in which the positive electrode, negative electrode, and separator are wound, or a form in which the positive electrode, negative electrode, and separator are stacked. The positive electrode may have a positive electrode current collector containing aluminum coated with a positive electrode active material, and the negative electrode may have a negative electrode current collector containing copper coated with a negative electrode active material.

[0040] The pouch cell 10 according to the present invention is used in the manufacturing process of a rechargeable secondary battery and may have a form in which a portion of the case 100 is not removed compared to the finished product. Hereinafter, in order to distinguish it from the pouch cell 10, the secondary battery that is a finished product manufactured by the secondary battery manufacturing method will be referred to as the final pouch-type cell.

[0041] The pouch cell 10 used in the manufacturing method of a secondary battery for producing the final pouch-type cell may further include a gas removal member 200 as an example of a configuration for removing gas generated during the manufacturing process.

[0042] In this regard, the case 100 of the pouch cell 10 may contain an electrolyte. In the method for manufacturing a secondary battery, once the electrode assembly 300 and the electrolyte are housed inside the case 100, an activation process can be performed. During the activation process, gases such as carbon dioxide may be generated inside the case 100. The generated gases are collected inside the case 100 and then discharged to the outside through holes or the like. Here, the gas removal member 200 of the pouch cell 10 can remove the gas generated inside the case 100. Details regarding the gas removal member 200 will be described later.

[0043] As described above, the case 100 of the pouch cell 10 can be configured in pairs. Here, the pair of cases 100 can house the electrode assembly 300 and the gas removal member 200 inside.

[0044] At least one of the pair of cases 100 may include a cup portion 110 molded to accommodate the electrode assembly 300 and a terrace portion 120 forming the periphery of the cup portion 110. That is, the cup portion 110 may be molded only in the first case 101, or it may be molded in both the first case 101 and the second case 102. The gas generated in the activation process described above can be collected in the terrace portion 120 of the case 100.

[0045] On the other hand, the gas removal member 200 of the pouch cell 10 according to one embodiment of the present invention can be placed on the terrace portion 120 of the case 100. Referring to Figures 1 and 2, the gas removal member 200 can be placed with a gap between it and the cup portion 110 of the case 100. After the activation process, the case 100 can be cut and partially removed based on the cut portion 140 formed between the cup portion 110 and the terrace portion 120. Therefore, the gas removal member 200 that has removed the gas from inside the case 100 in the activation process is removed along with a portion of the case 100, and the final pouch cell does not include the gas removal member 200. Since the gas removal member 200 is placed with a gap between it and the cup portion 110, the process of removing a portion of the case 100 can be carried out more efficiently.

[0046] The pouch cell 10 according to one embodiment of the present invention includes a gas removal member 200, allowing the case 100 to have a relatively small volume of gas collection space. That is, the amount of gas collection space to be removed can be reduced, thereby lowering the production cost of the final pouch-type cell. Furthermore, conventionally, as the amount of gas generated in the process increased, it was necessary to increase the gas collection space. However, the pouch cell 10 according to one embodiment of the present invention, with the gas removal member 200, can reduce the need to increase the gas collection space. Therefore, the process efficiency of the secondary battery manufacturing method can be improved.

[0047] As an example of a configuration for efficiently removing gas, the gas removal member 200 according to one embodiment of the present invention may include a gas absorbent (not shown). The gas absorbent of the gas removal member 200 can absorb gas through a chemical reaction.

[0048] In relation to the chemical reaction of the gas absorbent, the gas absorbent may contain sodium hydroxide (NaOH) or calcium hydroxide (Ca(OH)2). During the activation process, a large amount of carbon dioxide (CO2) may be generated inside the case 100 of the pouch cell 10. The carbon dioxide generated during the activation process can be removed by reacting with sodium hydroxide or calcium hydroxide. Here, carbon dioxide can chemically react with sodium hydroxide or calcium hydroxide to generate water and heat. Experiments have shown that the amount of water and heat generated by the chemical reaction of carbon dioxide is very small and can not affect the process.

[0049] The gas absorbent of the gas removal member 200 according to one embodiment of the present invention can remove carbon dioxide more efficiently by containing sodium hydroxide or calcium hydroxide.

[0050] For more efficient carbon dioxide removal, the gas absorbent may also contain soda lime. Here, soda lime can refer to a granular substance that has the property of absorbing carbon dioxide and water. Soda lime may also contain sodium hydroxide, calcium hydroxide, and anhydrous silicic acid (silica).

[0051] On the other hand, the gas absorbent of the gas removal member 200 may further contain substances that remove other gases in addition to carbon dioxide. Specifically, the gas absorbent may further contain a substance that removes at least one of O2, C2H4, C2H6, and CO. Therefore, the gas absorbent of the gas removal member 200 can remove other gases in addition to carbon dioxide from the gases generated in the activation process. Here, the substances that remove O2, C2H4, C2H6, and CO can vary.

[0052] As an example of a configuration for housing a gas absorbent, the gas removal member 200 according to one embodiment of the present invention may further include an outer casing (not shown). That is, the gas absorbent can be arranged while housed in the outer casing.

[0053] The outer casing of the gas removal member 200 can be in the form of a pocket with a substantially rectangular cross-section. Here, a gas absorbent can be housed inside the pocket-shaped outer casing.

[0054] On the other hand, the outer casing of the gas removal member 200 may include a porous material. Specifically, the outer casing of the gas removal member 200 can be made of a porous material. Here, a porous material may mean a material that allows gases to pass through but does not allow solids to pass through.

[0055] Since the outer casing of the gas removal member 200 contains a porous material, it prevents the gas absorbent from leaking out of the casing, and allows the gas to be removed to move smoothly to the gas absorbent.

[0056] Figure 3 is an exploded perspective view schematically illustrating a pouch cell 10 according to one embodiment of the present invention.

[0057] In one embodiment of the present invention, the cases 100 of the pouch cell 10 can be arranged in pairs facing each other. Each pair of opposing cases 100 may include a terrace portion 120, and a gas pocket portion can be formed between the opposing terrace portions 120. As described above, gas generated in the activation process can be collected in the gas pocket portion.

[0058] Referring to Figure 3, the gas removal member 200 of the pouch cell 10 can be placed in the gas pocket. That is, the gas removal member 200 can be placed in the space where the gas generated in the activation process is collected.

[0059] Since the gas removal member 200 is positioned in the gas pocket, it can be located in the same space as the gas generated in the activation process. Therefore, the gas removal member 200 can efficiently come into contact with the gas and efficiently remove it.

[0060] On the other hand, the gas removal member 200 of the pouch cell 10 according to one embodiment of the present invention can be eccentrically positioned in the gas pocket portion. Specifically, the gas removal member 200 can be positioned in a manner that is biased to one side with respect to the longitudinal direction of the gas pocket portion.

[0061] In this regard, the terrace portion 120 of case 100 may include an electrolyte injection portion 130. The electrolyte injection portion 130 can be an inlet for injecting electrolyte into the case 100 housing the electrode assembly 300. Specifically, the electrolyte injection portion 130 can be formed by a first case 101 and a second case 102 that are coupled to each other. More specifically, the electrolyte injection portion 130 can be formed at a position corresponding to one end of the terrace portion 120.

[0062] The electrolyte injection section 130 can be spaced apart from the gas removal member 200, which is eccentrically positioned in the gas pocket section. Therefore, interference by the gas removal member 200 can be minimized when the electrolyte is injected into the case 100. In addition, the gas removal member 200 is not affected by the injected electrolyte, reducing the risk of performance degradation.

[0063] On the other hand, the gas removal member 200 can be positioned so as to be spaced apart from one end of the terrace portion 120 in which the electrolyte injection portion 130 is formed. Therefore, when one end of the terrace portion 120 is sealed after the electrolyte has been injected through the electrolyte injection portion 130, the gas removal member 200 can be prevented from interfering with the sealing. This allows the sealing to be performed efficiently. Here, sealing can mean the process of sealing the opposing first case 101 and second case 102 together using heat and pressure, etc.

[0064] A pouch cell 10 according to one embodiment of the present invention can be an intermediate product for manufacturing a final pouch-type cell, which is a finished product. Since the pouch cell 10 includes a gas removal member 200, gas can be efficiently removed during the manufacturing process. Furthermore, since the gas removal member 200 is removed during the manufacturing process, it does not affect the shape of the final pouch-type cell.

[0065] Manufacturing method of secondary batteries In the following, a detailed explanation of the configuration of the pouch cell 10 according to one embodiment of the present invention will be omitted.

[0066] Figure 4 is a flowchart illustrating a schematic method for manufacturing a secondary battery according to another embodiment of the present invention.

[0067] Referring to Figure 4, a method for manufacturing a secondary battery according to another embodiment of the present invention may include the step (S1) of housing an electrode assembly 300 in a cup portion 110 formed in a case 100. Hereinafter, this step will be referred to as step (a). The case 100 may include a cup portion 110 for housing the electrode assembly 300. The cup portion 110 can be formed by molding a thin, plate-shaped pouch film. For example, the cup portion 110 can be formed by a molding apparatus or the like pressing a pouch film to form a concave space.

[0068] In another embodiment of the present invention, a method for manufacturing a secondary battery may be performed in which, after the electrode assembly 300 is housed in the cup portion 110 of the case 100 in step (a), a gas removal member 200 is placed inside the case 100 (S2). Hereinafter, this step will be referred to as step (b). Specifically, step (b) may include placing the gas removal member 200 between a pair of cases 100 and joining the pair of cases 100 so that they face each other.

[0069] On the other hand, in step (b), the gas removal member 200 can be placed on the terrace portion 120. Here, the terrace portion 120 may mean the portion of the case 100 that forms the periphery of the cup portion 110. The terrace portion 120 can be an unformed portion of the case 100. That is, in step (b), no further process is required to form the case 100 for the placement of the gas removal member 200. Therefore, the efficiency and economy of the process can be improved.

[0070] On the other hand, the gas removal member 200 can be attached to the inside of the terrace portion 120. Therefore, the gas removal member 200 can remain fixed and not move during the process of manufacturing the secondary battery. Here, there can be various methods for attaching the gas removal member 200 to the inside of the terrace portion 120.

[0071] In a method for manufacturing a secondary battery according to another embodiment of the present invention, after step (b) has been completed, an electrolyte can be injected into the case 100 which houses the electrode assembly 300 and the gas removal member 200. Here, the step of joining parts of a pair of cases 100 together to form an electrolyte injection section 130 may be performed first. That is, the remaining parts of the case 100 other than the electrolyte injection section 130 for injecting the electrolyte can be sealed. Here, sealing may mean the process of sealing opposing cases 100 together using heat and pressure, etc. After the sealing of the parts other than the electrolyte injection section 130 is completed, the electrolyte can be injected into the case 100.

[0072] On the other hand, as described in one embodiment of the present invention, the case 100 has a configuration in which the first case 101 and the second case 102 are connected to each other and can be folded relative to the connected portion. Alternatively, the first case 101 and the second case 102 can be joined so that they face each other while separated. In this case, the separated pair of cases 100 may have a wider portion that is sealed for joining than in the connected configuration.

[0073] In a method for manufacturing a secondary battery according to another embodiment of the present invention, the case 100, in which the electrolyte has been injected, can be sealed up to the electrolyte injection section 130, and an activation step (S3) can be performed in which the case is stored for a predetermined time while repeatedly charging and discharging the electrode assembly 300. Hereinafter, this step will be referred to as step (c).

[0074] In step (c), the pouch cell 10 is activated and gas can be generated inside the case 100. To remove the gas generated at this time, a method for manufacturing a secondary battery according to another embodiment of the present invention may include a step of removing the gas generated inside the case 100. That is, the gas generated by activation in step (c) can be removed by the gas removal member 200 housed in the case 100 in step (b). On the other hand, any gas not removed by the gas removal member 200 can be collected in the terrace portion 120 of the case 100.

[0075] The gas collected in the terrace portion 120 may affect the performance of the completed final pouch-type cell. Therefore, the method for manufacturing the secondary battery may include a step to remove the collected gas. In this regard, the method for manufacturing the secondary battery may include a step (S5, (d) step) of cutting along a cut portion 140 of the case 100 so that a portion of the case 100 containing the gas removal member 200 is removed. Here, the cut portion 140 of the case 100 may be formed in the terrace portion 120 and may be formed adjacent to the cup portion 110 in a form that extends along the longitudinal direction of the cup portion 110 (see Figure 2).

[0076] Since a portion of the terrace section 120 where the gas is collected and the gas removal member 200 are removed, most of the gas and gas removal member 200 generated during the process can be left in the completed final pouch-type cell.

[0077] On the other hand, in step (b), the gas removal member 200 can be positioned at a distance from the cup portion 110 in which the electrode assembly 300 is housed. Specifically, the gas removal member 200 can be positioned at a distance from the cutting portion 140. Therefore, when the cutting portion 140 is cut, it is not interfered with by the gas removal member 200, and a portion of the case 100 can be efficiently removed.

[0078] A method for manufacturing a secondary battery according to another embodiment of the present invention may further include a step (S4) of sealing the cut portion 140 of the case 100 before step (d).

[0079] If the cut portion 140 is not sealed and the cut portion 140 is cut, electrolyte and other substances inside the case 100 may leak out. Therefore, sealing the cut portion 140 before step (d) is performed can prevent the electrolyte and other substances from leaking out.

[0080] As described above, in step (b), the gas removal member 200 can be positioned so as to be spaced apart from the cup portion 110 in which the electrode assembly 300 is housed. Specifically, the gas removal member 200 can be positioned so as to be spaced apart from the cut portion 140. Therefore, when the cut portion 140 is sealed, it is not interfered with by the gas removal member 200, and sealing can be performed efficiently.

[0081] Another embodiment of the present invention provides a method for manufacturing a secondary battery that includes the step of placing a gas removal member 200 on the terrace portion 120 of the case 100. This allows for more efficient removal of gas from inside the case 100 during the gas removal process. Furthermore, the secondary battery manufacturing method requires relatively less space for gas collection, reducing the amount of case 100 removed and improving the efficiency and cost-effectiveness of the process.

[0082] The above description is merely illustrative of the technical concept of the present invention, and any person with ordinary skill in the art to which the present invention belongs can make various modifications and alterations without departing from the essential characteristics of the present invention.

[0083] Therefore, the embodiments disclosed in this invention are for illustrative purposes only, and not to limit the technical concept of the invention, and the scope of the technical concept of the invention is not limited by such embodiments.

[0084] The scope of protection of this invention shall be interpreted in accordance with the following claims, and all technical ideas within an equivalent scope shall be interpreted as being included within the scope of the rights of this invention. [Explanation of symbols]

[0085] 10 pouch cells 100 cases 101 Case 1 102 Case 2 110 cup section 120 Terrace section 130 Electrolyte injection part 140 Cutting section 200 Gas removal component 300 electrode assembly

Claims

1. Electrode assembly and A gas removal member for removing gas generated in the electrode assembly, The electrode assembly and a pair of cases that house the gas removal member inside are included. At least one of the pair of cases includes a cup portion molded to accommodate the electrode assembly and a terrace portion forming the periphery of the cup portion, The aforementioned gas removal member is A pouch cell is placed in the aforementioned terrace section.

2. The aforementioned gas removal member is The pouch cell according to claim 1, comprising a gas absorbent capable of absorbing the gas by a chemical reaction.

3. The aforementioned gas removal member is It further comprises an exterior part containing a porous material, The pouch cell according to claim 2, wherein the gas absorbent is housed inside the outer casing.

4. The aforementioned gas absorbent is CO generated in the electrode assembly ２ Remove NaOH or Ca(OH) ２ The pouch cell according to claim 2, comprising:

5. The aforementioned gas absorbent is O generated in the electrode assembly ２ , C ２ H ４ , C ２ H ６ The pouch cell according to claim 2, comprising a substance that removes at least one of CO.

6. The aforementioned terrace section is The pouch cell according to claim 1 or 2, comprising an electrolyte injection section disposed at one end so as to be spaced apart from the gas removal member.

7. The pair of cases are arranged so as to face each other. A gas pocket is formed between the opposing terrace portions, where gas generated in the electrode assembly is collected. The aforementioned gas removal member is The pouch cell according to claim 1 or 2, which is disposed in the gas pocket portion.

8. The aforementioned gas removal member is The pouch cell according to claim 7, which is eccentrically arranged in the gas pocket portion.

9. (a) A step of housing the electrode assembly in a cup portion formed in the case, (b) The step of placing a gas removal member inside the case, (c) The step of charging and discharging the electrode assembly to activate it, (d) A method for manufacturing a secondary battery, comprising the step of cutting along a cut portion of the case so that a portion of the case including the gas removal member is removed.

10. The method for manufacturing a secondary battery according to claim 9, further comprising the step of sealing the cut portion of the case before step (d).

11. In step (b) above, The method for manufacturing a secondary battery according to claim 9, wherein the gas removal member is arranged to have a gap between it and the cup portion.

12. In step (b) above, The method for manufacturing a secondary battery according to claim 9 or 10, wherein the gas removal member is arranged to adhere to the inside of the case.

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