Battery cell manufacturing method

Abstract

A battery cell manufacturing method according to one embodiment of the present invention includes: a battery cell assembling step of mounting, in a receiving part of a battery case, an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode; a needle part insertion step of inserting a needle part into the electrode assembly; and an electrolyte injection and sealing step of injecting an electrolyte into the battery case in a state in which the needle part is inserted into the electrode assembly, and then sealing the battery case.

Description

Battery cell manufacturing method

[0001] Cross-citation with related application(s)

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0146682, filed October 30, 2023, the entire contents of which are incorporated herein by reference.

[0003] The present invention relates to a method for manufacturing a battery cell, and more specifically, to a method for manufacturing a battery cell that facilitates the discharge of air and / or gas generated within a battery cell during the process while improving the wettability of an electrolyte solution to an electrode.

[0004] As technological developments and demand for mobile devices increase, the demand for secondary batteries as an energy source is rapidly increasing. In particular, secondary batteries are attracting significant attention as an energy source not only for mobile devices such as cell phones, digital cameras, laptops, and wearable devices, but also for powertrains such as electric bicycles, electric cars, and hybrid electric vehicles.

[0005] These secondary batteries are classified into cylindrical and prismatic batteries, in which the electrode assembly is housed in a cylindrical or prismatic metal can, and pouch-type batteries, in which the electrode assembly is housed in a pouch-type case made of aluminum laminate sheet, depending on the shape of the battery case. Here, the electrode assembly housed in the battery case is a power plant capable of charging and discharging, consisting of a positive electrode, a negative electrode, and a separator structure interposed between the positive electrode and the negative electrode, and is classified into a jelly-roll type in which a separator is interposed between long sheet-shaped positive and negative electrodes coated with an active material and wound, and a stack type in which a plurality of positive electrodes and negative electrodes are sequentially stacked while interposing the separator between them.

[0006] Among these, pouch-type batteries, which have a structure in which a stack-type or stack / folding-type electrode assembly is built into a pouch-type battery case made of aluminum laminate sheet, are gradually increasing in usage due to reasons such as low manufacturing cost, small weight, and easy deformation.

[0007] However, in manufacturing pouch-type batteries, the electrolyte may be injected into the pouch-type battery case while the electrode assembly is built in. In particular, during the manufacturing process of the pouch-type battery, air, gas, etc. trapped between the electrodes and separators of the electrode assembly or between electrodes may not be discharged. Such air, gas, etc. may interfere with the charging and discharging of the battery, leading to problems such as lithium plating or a decrease in battery capacity.

[0008] Accordingly, there is a need to develop a battery cell manufacturing method that improves the wettability of the electrolyte to the electrode while facilitating the discharge of air and / or gas generated within the battery cell during the manufacturing process.

[0009] The problem to be solved by the present invention is to provide a method for manufacturing a battery cell that improves the wettability of an electrolyte while facilitating the discharge of air and / or gas generated inside the battery cell during the process.

[0010] The problems to be solved by the present invention are not limited to the problems described above, and problems not mentioned can be clearly understood by a person having ordinary skill in the art to which the present invention pertains from this specification and the attached drawings.

[0011] A battery cell manufacturing method according to one embodiment of the present invention includes a battery cell assembly step of mounting an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode into a receiving portion of a battery case; a needle insertion step of inserting a needle into the inside of the electrode assembly; and an electrolyte injection and sealing step of injecting an electrolyte into the inside of the battery case while the needle is inserted into the inside of the electrode assembly and then sealing the battery case.

[0012] In the above needle portion insertion step, the needle portion may be inserted between the separator and the anode, which are positioned adjacent to each other, or between the separator and the cathode, which are positioned adjacent to each other.

[0013] In the above needle portion insertion step, the needle portion can be inserted between the separator and the anode, which are positioned adjacent to each other, and can be inserted between the separator and the cathode, which are positioned adjacent to each other.

[0014] The above needle portion may be inserted into the center of the electrode assembly.

[0015] The above needle portion may include at least one needle extending along the width direction of the electrode assembly.

[0016] The thickness of the above needle may be 0.2 mm or more and 1 mm or less.

[0017] The at least one needle may be arranged in a diagonal direction with respect to the thickness direction of the electrode assembly.

[0018] The above needle portion further includes a connecting portion extending along the thickness direction of the electrode assembly, and one end of the at least one needle may be fixed to the connecting portion.

[0019] The above connecting portion may be located between the electrode assembly and the sealing portion.

[0020] After the electrolyte injection and sealing steps, the method may further include an activation step for activating the battery cell, and a degassing and needle removal step for removing gas generated inside the battery cell and removing the needle part.

[0021] In the above degassing and needle removal step, a space between the sealing portion of the battery case and the electrode assembly may be cut to form an opening on one side of the battery case.

[0022] In the above degassing and needle removal step, a needle removal part can be inserted into the opening to remove the needle part from the electrode assembly.

[0023] After the degassing and needle removal steps, the method may further include a pressure rolling step of pressing and rolling the outer surface of the battery cell, and a re-sealing step of re-sealing the cut portion between the sealing portion of the battery case and the electrode assembly.

[0024] The above activation step may include a pre-aging step of storing the battery cell at room temperature, a formation step of charging and discharging the battery cell at least once, and an aging step of storing the battery cell at high temperature.

[0025] According to embodiments, the battery cell manufacturing method of the present invention can improve the wettability of the electrolyte to the electrode while facilitating the discharge of air and / or gas generated inside the battery cell during the process.

[0026] The effects of the present invention are not limited to the effects described above, and effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present invention pertains from this specification and the attached drawings.

[0027] Figure 1 is a flowchart showing a battery cell manufacturing method according to one embodiment of the present invention.

[0028] Figure 2 is a perspective view showing a battery cell after the electrolyte injection and sealing steps of Figure 1.

[0029] Figure 3 is a drawing showing an enlarged portion of a cross-section cut along the a-a' axis of Figure 2.

[0030] Figure 4 is a drawing showing a cross-section taken along the b-b' axis of Figure 2.

[0031] Figure 5 is a perspective view showing a battery cell in the degassing and needle removal step of Figure 1.

[0032] Fig. 6 is a perspective view showing a needle removal part and a needle part inserted into an opening of a battery cell of Fig. 5.

[0033] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0034] In order to clearly explain the present invention, parts that are not related to the description are omitted, and the same reference numerals are used for identical or similar components throughout the specification.

[0035] Furthermore, the sizes and thicknesses of each component shown in the drawings are arbitrarily indicated for convenience of explanation, and thus the present invention is not necessarily limited to the illustrated components. In the drawings, the thicknesses are enlarged to clearly represent various layers and regions. Furthermore, in the drawings, the thicknesses of some layers and regions are exaggerated for convenience of explanation.

[0036] Additionally, throughout the specification, whenever a part is said to “include” a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0037] Additionally, throughout the specification, when we say "in plan", we mean when the target portion is viewed from above, and when we say "in cross section", we mean when the target portion is viewed from the side in a cross-section cut vertically.

[0038] Hereinafter, a method for manufacturing a battery cell according to an embodiment of the present invention will be described.

[0039] Fig. 1 is a flowchart illustrating a method for manufacturing a battery cell according to one embodiment of the present invention. Fig. 2 is a perspective view illustrating a battery cell after the electrolyte injection and sealing steps of Fig. 1. Fig. 3 is an enlarged view illustrating a portion of a cross-section taken along the a-a' axis of Fig. 2. Fig. 4 is a view illustrating a cross-section taken along the b-b' axis of Fig. 2.

[0040] Referring to FIGS. 1 to 3, a battery cell manufacturing method according to an embodiment of the present invention includes a battery cell assembling step (S100) of mounting an electrode assembly (110) including a positive electrode (111), a negative electrode (113), and a separator (115) interposed between the positive electrode (111) and the negative electrode (113) into a receiving portion (123) of a battery case (120); a needle part inserting step (S200) of inserting a needle part (200) into the electrode assembly (100); and an electrolyte injection and sealing step (S300) of forming a sealing portion (120s) in the battery case (120) after injecting an electrolyte into the battery case (120) while the needle part (200) is inserted into the electrode assembly (110).

[0041] Referring to FIG. 2, the battery cell (100) assembled in the battery cell assembly step (S100) is a pouch battery cell and includes an electrode assembly (110) inside a battery case (120). In addition, the battery cell (100) has a structure in which electrode leads (150) connected to electrode tabs (not shown) of the electrode assembly (110) are exposed to the outside, and lead films (not shown) are attached to the upper and lower portions of the electrode leads (150).

[0042] The electrode assembly (110) includes a positive electrode (111), a negative electrode (113), and a separator (115). More specifically, the electrode assembly (110) may be configured such that the positive electrode (111) and the negative electrode (113) are sequentially stacked with the separator (115) interposed therebetween and are insulated from each other. Here, the electrode assembly (110) may be a stack-type electrode assembly or a stack / folding-type electrode assembly. However, the shape of the electrode assembly (110) is not limited thereto, and any assembly shape including the positive electrode (111), the negative electrode (113), and the separator (115) may be included in the present embodiment. In addition, the positive electrode (111), the negative electrode (113), and the separator (115) may be formed of a material generally included in a battery cell.

[0043] The electrode lead (150) may include a positive lead (151) connected to the positive tabs (not shown) of the electrode assembly (110) and a negative lead (155) connected to the negative tabs (not shown) of the electrode assembly (110). In addition, a first lead film (161) may be attached to the upper and lower portions of the positive lead (151), and a second lead film (165) may be attached to the upper and lower portions of the negative lead (155). However, as illustrated in FIG. 2, the position of the electrode lead (150) is not limited to being located at both ends of the electrode assembly (110), and the positive lead (151) and the negative lead (155) may be located together at one end of the electrode assembly (110).

[0044] In the battery cell assembly step (S100), the assembled battery cell (100) may have an outer peripheral portion (125) formed by heat-sealing the outer peripheral portions of the battery case (120) to each other while the electrode assembly (110) is mounted in a concave-shaped receiving portion (123) formed in the battery case (120).

[0045] As shown in FIG. 2, one side of the battery case (120) may have a structure that extends outward from the receiving portion (123), and one side of the battery case (120) may extend with a relatively wider width than the other side of the battery case (120). In addition, in the battery cell assembly step (S100), the battery cell (100) assembled may have the electrode assembly (110) built into the receiving portion (123) in a state where at least one side of the battery case (120) is unsealed. Here, at least one side of the battery case (120) may be a side of the electrode assembly (110) where the electrode lead (150) is not positioned.

[0046] Referring to FIGS. 1 and 3, in the needle insertion step (S200), the needle (200) can be inserted between adjacent components among the positive electrode (111), the negative electrode (113), and the separator (115) included in the electrode assembly (100). More specifically, the needle (200) can be inserted between the separator (115) and the positive electrode (111) which are adjacent to each other, or between the separator (115) and the negative electrode (113) which are adjacent to each other. In addition, the needle (200) can be inserted between the separator (115) and the positive electrode (111) which are adjacent to each other, and between the separator (115) and the negative electrode (113) which are adjacent to each other.

[0047] For example, as shown in FIG. 3, the needle portion (200) may be positioned between the anode (111) and / or cathode (113) and the separator (115), which are positioned adjacent to different separators (115). As another example, although not shown in the drawing, the needle portion (200) may be positioned between the anode (111) and cathode (113) and the separator (115), which are positioned adjacent to the same separator (115).

[0048] Accordingly, in the battery cell manufacturing method according to the present embodiment, the needle part insertion step (S200) inserts the needle part (200) into the electrode assembly (100), so that air or gas trapped between the positive electrode (111) and / or negative electrode (113) and the separator (115) can be discharged to the outside of the electrode assembly (100), and lithium plating and capacity reduction that may be caused by such air or gas can be prevented.

[0049] In addition, the needle portion (200) can form a fine step between the positive electrode (111) and / or negative electrode (113) and the separator (115), and capillary force can be generated due to this step. That is, when the electrolyte is injected while the needle portion (200) is inserted into the electrode assembly (100), the wettability of the electrolyte to the positive electrode (111) and / or negative electrode (113) can be further improved.

[0050] The needle portion (200) may be inserted into the center of the electrode assembly (110). In other words, the needle portion (200) may be positioned between the separator (115) positioned at the center of the electrode assembly (110) and the positive electrode (111) and / or negative electrode positioned adjacent to the separator (115). Here, the center of the electrode assembly (110) may mean the center portion based on the thickness direction of the electrode assembly (110).

[0051] Accordingly, in the battery cell manufacturing method according to the present embodiment, the needle portion insertion step (S200) inserts the needle portion (200) into the center of the electrode assembly (100), thereby further improving the wettability of the positive electrode (111) and / or negative electrode (113) located at the center of the electrode assembly (110), so that the wettability of the electrolyte can be relatively uniform depending on the position of the electrode assembly (110).

[0052] More specifically, as shown in FIG. 3, the needle portion (200) may include at least one needle (210) extending along the width direction of the electrode assembly (110).

[0053] As shown in FIG. 3, the needle (210) may extend along the width direction of the electrode assembly (110) to a portion passing through the center of the electrode assembly (110). As another example, unlike FIG. 3, the needle (210) may extend along the width direction of the electrode assembly (110) to the center of the electrode assembly (110) or to an end of the electrode assembly (110). Here, the length of the needle (210) may be adjusted so as not to interfere with the wetting of the electrolyte on the positive electrode (111) and / or negative electrode (113) of the electrode assembly (110).

[0054] Accordingly, in the battery cell manufacturing method according to the present embodiment, the needle insertion step (S200) can further improve the wettability of the electrolyte to the positive electrode (111) and / or negative electrode (113) without interfering with the wetting of the electrolyte to the positive electrode (111) and / or negative electrode (113) of the electrode assembly (110) by adjusting the length of at least one needle (210).

[0055] For example, the thickness of the needle (210) may be 0.2 mm or more and 1 mm or less. However, the thickness of the needle (210) is not limited thereto, and the thickness of the needle (210) may be adjusted to a degree that does not interfere with the wetting of the electrolyte on the positive electrode (111) and / or negative electrode (113) of the electrode assembly (110).

[0056] Accordingly, in the battery cell manufacturing method according to the present embodiment, the needle insertion step (S200) can further improve the wettability of the electrolyte to the positive electrode (111) and / or negative electrode (113) without interfering with the wetting of the electrolyte to the positive electrode (111) and / or negative electrode (113) of the electrode assembly (110) by adjusting the thickness of at least one needle (210).

[0057] Additionally, as shown in FIG. 3, at least one needle (210) may be arranged in a diagonal direction based on the thickness direction of the electrode assembly (110). However, the arrangement direction of the needle (210) is not limited thereto, and may be arranged in the same direction as the thickness direction of the electrode assembly (110).

[0058] Accordingly, in the battery cell manufacturing method according to the present embodiment, the needle insertion step (S200) can further improve the wettability of the electrode assembly (110) to the positive electrode (111) and / or negative electrode (113) by inserting at least one needle (210) into multiple locations inside the electrode assembly (100), so that the wettability of the electrolyte can be more uniform depending on the location of the electrode assembly (110).

[0059] In particular, as shown in FIG. 3, when at least one needle (210) is arranged diagonally with respect to the thickness direction of the electrode assembly (110), the needles (210) are arranged at different positions with respect to the thickness direction of the electrode assembly (110), so that the wettability of the electrolyte can be made more uniform depending on the position of the electrode assembly (110).

[0060] For example, at least one needle (210) may have a bar or stick structure with a circular or square cross-section, or may have a porous structure. However, the shape of the needle (210) is not limited thereto, and the shape of the needle (210) may be a shape that does not hinder the wetting of the electrolyte on the positive electrode (111) and / or negative electrode (113) of the electrode assembly (110).

[0061] For example, at least one needle (210) may be made of a non-metallic material. As another example, at least one needle (210) may be made of a chemically resistant, acid-resistant, and alkali-resistant material. However, the material of the needle (210) is not limited thereto, and the material of the needle (210) may be a material that does not react with the electrolyte and does not interfere with the wetting of the electrolyte on the positive electrode (111) and / or negative electrode (113) of the electrode assembly (110).

[0062] In addition, as shown in FIGS. 3 and 4, the needle portion (200) may further include a connecting portion (250) extending along the thickness direction of the electrode assembly (110). In the needle portion (200), one end of at least one needle (210) may be fixed to the connecting portion (250). For example, one end of at least one needle (210) and the connecting portion (250) may be fixed to each other by a joining method such as welding, adhesion, or the like. As another example, one end of at least one needle (210) and the connecting portion (250) may be an integrated structure in a fixed state.

[0063] Accordingly, in the battery cell manufacturing method according to the present embodiment, in the needle portion insertion step (S200), the needle portion (200) inserted into the electrode assembly (110) has a structure in which one end of at least one needle (210) is fixed to the connecting portion (250), thereby assisting in fixing at least one needle (210) to a predetermined position. In addition, there is an advantage in that at least one needle (210) included in the needle portion (200) can be removed all at once in the subsequent needle portion removal step (S700).

[0064] Additionally, the connecting portion (250) may be positioned between the electrode assembly (110) and the sealing portion (120s). For example, if there is sufficient space inside the receiving portion (123), the connecting portion (250) may be positioned inside the receiving portion (123) together with the electrode assembly (110). Alternatively, if there is not sufficient space inside the receiving portion (123), the connecting portion (250) may be positioned outside the receiving portion (123).

[0065] Accordingly, in the battery cell manufacturing method according to the present embodiment, in the needle portion insertion step (S200), the connecting portion (250) included in the needle portion (200) is positioned between the electrode assembly (110) and the sealing portion (120s), so that the needle portion (200) can be easily inserted into the battery cell (100), and the needle portion (200) can be easily removed from the battery cell (100).

[0066] However, the structure of the needle portion (200) is not limited thereto, and unlike FIG. 3, a structure in which the connecting portion (250) is omitted from the needle portion (200) may also be included in the present embodiment. In addition, in the case of a structure in which the connecting portion (250) is omitted from the needle portion (200), at least one needle (210) may be removed in the needle portion removal step (S700) described below.

[0067] Referring to FIG. 1, in the electrolyte injection and sealing step (S300), the electrolyte injected into the battery cell (100) refers to a liquid electrolyte, through which ions can move between the positive and negative electrodes, and through this ion exchange between the positive and negative electrodes, the battery cell (100) can be charged and discharged. As an example, the electrolyte may include, but is not limited to, an organic liquid electrolyte, an inorganic liquid electrolyte, a solid polymer electrolyte, a gel-type polymer electrolyte, a solid inorganic electrolyte, a molten inorganic electrolyte, and the like.

[0068] Referring to FIGS. 1 and 2, in the electrolyte injection and sealing step (S300), the battery cell (100) can be sufficiently injected with electrolyte into the battery case (120) while the needle portion (200) is inserted into the electrode assembly (110), and then one unsealed side of the battery case (120) can be heat-sealed to form a sealing portion (120s).

[0069] Accordingly, in the battery cell manufacturing method according to the present embodiment, the electrolyte injection and sealing step (S300) sufficiently injects the electrolyte into the battery cell (100) through one unsealed side of the battery cell (100), and then forms a sealing portion (120s) on the one unsealed side of the battery cell (100), thereby sealing the internal space of the battery cell (100).

[0070] Fig. 5 is a perspective view showing a battery cell in the degassing and needle removal steps of Fig. 1. Fig. 6 is a perspective view showing a needle removal part and a needle part inserted into an opening of the battery cell of Fig. 5.

[0071] After the electrolyte injection and sealing step (S300), an activation step for activating the battery cell (100) may be further included; a degasing and needle removal step (S700) for removing gas generated inside the battery cell (100) and removing the needle part (200).

[0072] Referring to FIG. 1, the activation step may include a pre-aging step (S400) of storing the battery cell (100) at room temperature, a formation step (S500) of charging and discharging the battery cell (100) at least once, and an aging step (S600) of storing the battery cell (100) at high temperature.

[0073] Here, in the battery cell manufacturing method according to the present embodiment, since the activation step is performed while the needle portion (200) is inserted into the electrode assembly (110), the gas generated inside the battery cell (100) during the activation step can be more effectively discharged to the outside of the electrode assembly (110), and lithium plating and capacity reduction that may be generated by such air or gas can be more effectively prevented.

[0074] Referring to FIGS. 1, 2, and 5, in the degassing and needle removal step (S700), a cutting process may be performed between the sealing portion (120s) of the battery case (120) and the electrode assembly (110), so that an opening (127) may be formed on one side of the battery case (120). More specifically, the battery cell (100) may be cut along a first line (L1) located between the sealing portion (120s) of the battery case (120) and the electrode assembly (110), as shown in FIG. 2, so that an opening (127) may be formed on one side of the battery cell (100), as shown in FIG. 5.

[0075] Accordingly, in the battery cell manufacturing method according to the present embodiment, the degassing and the needle part step (S700) can discharge air or gas generated inside the battery cell (100) to the outside through the opening (127) formed on one side of the battery cell (100).

[0076] Referring to FIGS. 5 and 6, in the degassing and needle removal step (S700), a needle removal part (300) is inserted into the opening (127) to remove the needle part (200) from the electrode assembly (110). For example, as shown in FIG. 6, the needle removal part (300) is in contact with the needle part (200), and as the needle removal part (300) moves in the direction toward the opening (127), the needle part (200) also moves together, so that the needle part (200) can be removed from the electrode assembly (110).

[0077] Accordingly, in the battery cell manufacturing method according to the present embodiment, the degassing and needle part step (S70) can relatively easily remove the needle part (200) from the electrode assembly (110) through the needle removal part (300).

[0078] Referring to FIGS. 1 and 2, the battery cell manufacturing method according to the present embodiment may further include a pressure rolling step (S800) of pressing and rolling the outer surface of the battery cell (100) after the degassing and needle removal step (S700).

[0079] Accordingly, in the battery cell manufacturing method according to the present embodiment, the pressurized rolling step (S800) can discharge air or gas trapped inside the electrode assembly (100) that was not removed in the degassing and needle part removal step (S700) to the outside through the opening (127).

[0080] Referring to FIGS. 1 and 2, the battery cell manufacturing method according to the present embodiment may include a re-sealing step (S900) of re-sealing the cut portion between the sealing portion (120s) of the battery case (120) and the electrode assembly (110). More specifically, the battery cell (100) may be heat-sealed along a second line (L2) positioned adjacent to the receiving portion (123) of the battery case (120) to seal one side of the battery case (120), as shown in FIG. 2.

[0081] Accordingly, in the battery cell manufacturing method according to the present embodiment, the resealing step (S900) can seal the internal space of the battery cell (100) by resealing one side of the battery cell (100) in a state where air or gas inside the battery cell (100) has been sufficiently removed.

[0082] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

[0083] [Explanation of symbols]

[0084] 100: Battery cell

[0085] 110: Electrode assembly

[0086] 111: Bipolar

[0087] 113: Cathode

[0088] 115: Membrane

[0089] 120: Battery case

[0090] 120s: Sealing part

[0091] 123: Storage compartment

[0092] 125: Outsourcing

[0093] 127: Aperture

[0094] 150: Electrode lead

[0095] 200: Needle

[0096] 210: Needle

[0097] 250: Connection

[0098] 300: Needle removal unit

Claims

1. A battery cell assembly step of mounting an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode into a storage portion of a battery case; A needle insertion step for inserting a needle into the electrode assembly; and A battery cell manufacturing method including an electrolyte injection and sealing step in which an electrolyte is injected into the battery case while the needle portion is inserted into the electrode assembly and the battery case is then sealed.

2. In paragraph 1, In the above needle insertion step, A battery cell manufacturing method in which the needle portion is inserted between the separator and the positive electrode, which are positioned adjacent to each other, or between the separator and the negative electrode, which are positioned adjacent to each other.

3. In paragraph 1, In the above needle insertion step, A battery cell manufacturing method in which the needle portion is inserted between the separator and the positive electrode, which are positioned adjacent to each other, and between the separator and the negative electrode, which are positioned adjacent to each other.

4. In paragraph 1, A method for manufacturing a battery cell, wherein the needle portion is inserted into the center of the electrode assembly.

5. In paragraph 1, A method for manufacturing a battery cell, wherein the needle portion includes at least one needle extending along the width direction of the electrode assembly.

6. In paragraph 5, A method for manufacturing a battery cell, wherein the thickness of the needle is 0.2 mm or more and 1 mm or less.

7. In paragraph 5, A method for manufacturing a battery cell, wherein at least one needle is arranged in a diagonal direction with respect to the thickness direction of the electrode assembly.

8. In paragraph 5, The above needle portion further includes a connecting portion extending along the thickness direction of the electrode assembly, A method for manufacturing a battery cell, wherein one end of at least one needle is fixed to the connecting portion.

9. In paragraph 8, A battery manufacturing method wherein the connecting portion is located between the electrode assembly and the sealing portion.

10. In paragraph 1, After the above electrolyte injection and sealing steps, An activation step for activating the above battery cell, and A battery cell manufacturing method further comprising a degassing and needle removal step for removing gas generated inside the battery cell and removing the needle part.

11. In paragraph 10, A battery cell manufacturing method in which, in the degassing and needle removal step, a space between the sealing portion of the battery case and the electrode assembly is cut to form an opening on one side of the battery case.

12. In paragraph 11, A battery cell manufacturing method in which, in the above degassing and needle part removal step, a needle removal part is inserted into the opening to remove the needle part from the electrode assembly.

13. In paragraph 10, After the above degassing and needle removal steps, A pressure rolling step of pressing and rolling the outer surface of the above battery cell, and A battery cell manufacturing method further comprising a re-sealing step of re-sealing the cut portion between the sealing portion of the battery case and the electrode assembly.

14. In paragraph 10, The above activation step is, Pre-aging step of storing the above battery cells at room temperature, A formation step of charging and discharging the above battery cell at least once, and A method for manufacturing a battery cell, comprising an aging step of storing the battery cell at a high temperature.

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