Battery cell manufacturing method

Abstract

A method for manufacturing a battery cell according to one embodiment of the present invention includes a battery cell assembling 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 in a housing of a battery case; a needle part inserting 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 with the needle part inserted into the electrode assembly, and then sealing the battery case.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0146682 filed on October 30, 2023, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] 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 inside the battery cell during the manufacturing process and improves the wettability of the electrolyte to the electrodes. [Background technology]

[0003] With technological development and increasing demand for mobile devices, the demand for secondary batteries as an energy source is rapidly increasing. In particular, secondary batteries are attracting attention as an energy source not only for mobile devices such as mobile phones, digital cameras, laptops, and wearable devices, but also for power devices such as electric bicycles, electric vehicles, and hybrid electric vehicles.

[0004] These secondary batteries are classified into cylindrical and prismatic batteries, in which an electrode assembly is housed in a cylindrical or prismatic metal can, and pouch-type batteries, in which an electrode assembly is housed in a pouch-type case made of an aluminum laminate sheet, depending on the shape of the battery case. The electrode assembly housed in the battery case is a power-generating element that can be charged and discharged and includes a positive electrode, a negative electrode, and a separator membrane interposed between the positive and negative electrodes. The battery is classified into a jelly-roll type, in which a long sheet-like positive electrode and negative electrode coated with an active material are wound up with a separator membrane interposed between them, and a stack type, in which multiple positive electrodes and negative electrodes are stacked in sequence with a separator membrane interposed between them.

[0005] Among these, pouch-type batteries, which have a structure in which a stack-type or stack / fold-type electrode assembly is housed in a pouch-type battery case made of an aluminum laminate sheet, are gradually increasing in use due to their low manufacturing cost, small weight, and easy shape modification.

[0006] However, when manufacturing a pouch-type battery, the electrolyte is injected into the pouch-type battery case while the electrode assembly is still inside. In particular, during the manufacturing process of the pouch-type battery, air or gas trapped between the electrodes and the separator or between the electrodes of the electrode assembly may not be expelled. This air or gas may interfere with the charge and discharge of the battery, causing problems such as lithium plating or a decrease in battery capacity.

[0007] Therefore, it is necessary to develop a method for manufacturing a battery cell that improves the wettability of the electrolyte to the electrodes while facilitating the discharge of air and / or gas generated inside the battery cell during the manufacturing process. Summary of the Invention [Problem to be solved by the invention]

[0008] The problem to be solved by the present invention is to provide a method for manufacturing a battery cell that facilitates the discharge of air and / or gas generated inside the battery cell during the manufacturing process and improves the wettability of the electrolyte.

[0009] The problems to be solved by the present invention are not limited to those described above, and problems not mentioned will be clearly understood by a person having ordinary skill in the art to which the present invention pertains from this specification and the accompanying drawings. [Means for solving the problem]

[0010] A method for manufacturing a battery cell according to one embodiment of the present invention includes a battery cell assembling 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 in a housing of a battery case; a needle part inserting 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 with the needle part inserted into the electrode assembly, and then forming a sealing part in the battery case.

[0011] In the needle portion inserting step, the needle portion may be inserted between the separator and the positive electrode positioned adjacent to each other, or between the separator and the negative electrode positioned adjacent to each other.

[0012] In the needle portion inserting step, the needle portion may be inserted between the separator and the positive electrode positioned adjacent to each other, and between the separator and the negative electrode positioned adjacent to each other.

[0013] The needle portion can be inserted into the center of the electrode assembly.

[0014] The needle portion may include at least one needle extending along the width direction of the electrode assembly.

[0015] The thickness of the needle may be 0.2 mm or more and 1 mm or less.

[0016] The at least one needle may be disposed in a diagonal direction with respect to a thickness direction of the electrode assembly. The needle portion may further include a connecting portion extending along a thickness direction of the electrode assembly, and one end of the at least one needle may be fixed to the connecting portion.

[0017] The connecting portion may be located between the electrode assembly and the sealing portion.

[0018] After the electrolyte injection and sealing steps, the method may further include an activation step of activating the battery cell, and a degassing and needle part removal step of removing gas generated inside the battery cell and removing the needle part.

[0019] In the degassing and needle portion removing step, a portion between the sealing portion of the battery case and the electrode assembly may be cut to form an opening in one side of the battery case.

[0020] In the degassing and needle portion removal step, a needle removal portion can be inserted into the opening to remove the needle portion from the electrode assembly.

[0021] After the degassing and needle portion removing steps, the method may further include a pressure rolling step of pressing and rolling the outer surface of the battery cell, and a resealing step of resealing a portion cut between the sealing portion of the battery case and the electrode assembly.

[0022] The 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. [Effects of the Invention]

[0023] According to the embodiments, the method for manufacturing a battery cell of the present invention can easily discharge air and / or gas generated in the process from inside the battery cell, and can improve the wettability of the electrolyte to the electrodes.

[0024] The effects of the present invention are not limited to those described above, and unmentioned effects will be clearly understood by those skilled in the art to which the present invention pertains from this specification and the accompanying drawings. [Brief explanation of the drawings]

[0025] [Figure 1] 3 is a flowchart illustrating a method for manufacturing a battery cell according to an embodiment of the present invention. [Figure 2] 2 is a perspective view showing the battery cell of FIG. 1 after the electrolyte injection and sealing steps. FIG. [Figure 3] 3 is a diagram showing an enlarged view of a part of a cross section cut along the a-a' axis in FIG. 2. [Figure 4] 3 is a cross-sectional view taken along the bb' axis of FIG. 2. [Figure 5] FIG. 2 is a perspective view showing the battery cell in the degassing and needle part removal step of FIG. 1. [Figure 6] 6 is a perspective view showing a needle removal part and a needle part that are inserted into the opening of the battery cell in FIG. 5. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily implement various embodiments of the present invention. The present invention can be embodied in several different forms and is not limited to the examples described herein.

[0027] In order to clearly describe the present invention, parts that are not relevant to the description will be omitted and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0028] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for the convenience of explanation, and the present invention is not necessarily limited to those shown in the drawings. In the drawings, thicknesses are exaggerated to clearly show multiple layers and regions. In the drawings, thicknesses of some layers and regions are exaggerated for the convenience of explanation.

[0029] Also, throughout the specification, when a part is said to "comprise" a certain element, this means that it can further include other elements, rather than excluding other elements, unless otherwise specified.

[0030] Furthermore, throughout the specification, "on a plane" means a view of the target part from above, and "on a cross section" means a view of the target part cut vertically from the side.

[0031] Hereinafter, a method for manufacturing a battery cell according to an embodiment of the present invention will be described.

[0032] Fig. 1 is a flowchart showing a method for manufacturing a battery cell according to an embodiment of the present invention. Fig. 2 is a perspective view showing the battery cell after the electrolyte injection and sealing steps of Fig. 1. Fig. 3 is a partially enlarged cross-sectional view taken along the a-a' axis of Fig. 2. Fig. 4 is a cross-sectional view taken along the bb' axis of Fig. 2.

[0033] 1 to 3, a method for manufacturing a battery cell 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 injecting and sealing step (S300) of injecting an electrolyte into the battery case 120 with the needle part 200 inserted into the electrode assembly 110, and then forming a sealing portion 120s in the battery case 120.

[0034] 2, the battery cell 100 assembled in the battery cell assembling step (S100) is a pouch battery cell, and includes an electrode assembly 110 inside a battery case 120. The battery cell 100 has an electrode lead 150 connected to an electrode tab (not shown) of the electrode assembly 110 exposed to the outside, and lead films (not shown) attached to the top and bottom of the electrode lead 150.

[0035] 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 insulated from each other. Here, the electrode assembly 110 may be a stacked electrode assembly or a stacked / folded electrode assembly. However, the form of the electrode assembly 110 is not limited thereto, and any assembly form including the positive electrode 111, the negative electrode 113, and the separator 115 may be included in this embodiment. In addition, the positive electrode 111, the negative electrode 113, and the separator 115 may be made of materials commonly used in battery cells.

[0036] The electrode lead 150 may include a positive electrode lead 151 connected to a positive electrode tab (not shown) of the electrode assembly 110 and a negative electrode lead 155 connected to a negative electrode tab (not shown) of the electrode assembly 110. In addition, a first lead film 161 may be attached to the upper and lower parts of the positive electrode lead 151, and a second lead film 165 may be attached to the upper and lower parts of the negative electrode lead 155. However, the positions of the electrode leads 150 are not limited to being located at both ends of the electrode assembly 110 as shown in FIG. 2, and the positive electrode lead 151 and the negative electrode lead 155 may both be located at one end of the electrode assembly 110.

[0037] The battery cell 100 assembled in the battery cell assembling step (S100) may have the electrode assembly 110 mounted in a recessed receiving portion 123 formed in the battery case 120, with the outer surfaces of the battery case 120 heat-sealed to each other to form a sealed outer periphery 125.

[0038] 2, one side of the battery case 120 may have a structure that extends outward from the receiving portion 123, and the one side of the battery case 120 may extend with a width that is relatively wider than the other side of the battery case 120. In addition, the battery cell 100 assembled in the battery cell assembling step (S100) may have the electrode assembly 110 installed in the receiving portion 123 with at least one side of the battery case 120 remaining unsealed. Here, the at least one side of the battery case 120 may be a side of the electrode assembly 110 on which the electrode lead 150 is not positioned.

[0039] 1 and 3, in the needle part insertion step (S200), the needle part 200 may be inserted between adjacent components among the positive electrode 111, the negative electrode 113, and the separator 115 included in the electrode assembly 110. More specifically, the needle part 200 may 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 part 200 may 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.

[0040] 3, the needle portion 200 may be located between the separator 115 and the positive electrode 111 and / or the negative electrode 113, which are adjacent to different separators 115. As another example, although not shown in the drawing, the needle portion 200 may be located between the separator 115 and the positive electrode 111 and the negative electrode 113, which are adjacent to the same separator 115.

[0041] Therefore, in the method for manufacturing a battery cell according to this embodiment, the needle part insertion step (S200) inserts the needle part 200 into the electrode assembly 110, and air or gas trapped between the positive electrode 111 and / or negative electrode 113 and the separator 115 is discharged to the outside of the electrode assembly 110, thereby preventing lithium plating and capacity reduction that may occur due to such air or gas.

[0042] In addition, the needle part 200 may form a minute step between the positive electrode 111 and / or the negative electrode 113 and the separator 115, and such step may generate a capillary force. In other words, when an electrolyte solution is injected with the needle part 200 inserted into the electrode assembly 110, the wettability of the electrolyte solution to the positive electrode 111 and / or the negative electrode 113 may be further improved.

[0043] The needle portion 200 may be inserted into the center of the electrode assembly 110. That is, the needle portion 200 may be located between the separator 115 located in the center of the electrode assembly 110 and the positive electrode 111 and / or negative electrode located adjacent to the separator 115. Here, the center of the electrode assembly 110 may refer to the middle portion of the electrode assembly 110 in the thickness direction.

[0044] Therefore, in the battery cell manufacturing method according to this embodiment, the needle part insertion step (S200) inserts the needle part 200 into the center of the electrode assembly 110, which can further improve the wettability of the positive electrode 111 and / or negative electrode 113 located in the center of the electrode assembly 110, and the wettability of the electrolyte depending on the position of the electrode assembly 110 can become relatively uniform.

[0045] 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.

[0046] 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 wetting of the electrolyte to the positive electrode 111 and / or negative electrode 113 of the electrode assembly 110.

[0047] Therefore, in the battery cell manufacturing method according to this embodiment, the needle portion insertion step (S200) adjusts the length of at least one needle 210, thereby further improving the wettability of the electrolyte to the positive electrode 111 and / or negative electrode 113 without hindering the wetting of the electrolyte to the positive electrode 111 and / or negative electrode 113 of the electrode assembly 110.

[0048] For example, the thickness of the needle 210 may be 0.2 mm or more and 1 mm or less, but the thickness of the needle 210 is not limited thereto and may be adjusted so as not to hinder wetting of the electrolyte to the positive electrode 111 and / or the negative electrode 113 of the electrode assembly 110.

[0049] Therefore, in the battery cell manufacturing method according to this embodiment, the needle part insertion step (S200) adjusts the thickness of at least one needle 210, thereby further improving the wettability of the electrolyte to the positive electrode 111 and / or negative electrode 113 without hindering the wetting of the electrolyte to the positive electrode 111 and / or negative electrode 113 of the electrode assembly 110.

[0050] 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 needles 210 is not limited thereto, and the needles 210 may be arranged in the same direction as the thickness direction of the electrode assembly 110.

[0051] Therefore, in the battery cell manufacturing method according to this embodiment, the needle part insertion step (S200) inserts at least one needle 210 into various positions inside the electrode assembly 110, which can further improve the wettability of the electrode assembly 110 to the positive electrode 111 and / or negative electrode 113, and can make the wettability of the electrolyte depending on the position on the electrode assembly 110 more uniform.

[0052] In particular, when at least one needle 210 is arranged in a diagonal direction based on the thickness direction of the electrode assembly 110 as shown in FIG. 3, the needles 210 are arranged at different positions based on the thickness direction of the electrode assembly 110, and the wettability of the electrolyte depending on the position on the electrode assembly 110 can be more uniform.

[0053] For example, the at least one needle 210 may have a bar or stick structure having 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 any shape that does not prevent the electrolyte from wetting the positive electrode 111 and / or the negative electrode 113 of the electrode assembly 110.

[0054] As one example, the at least one needle 210 may be made of a non-metallic material. As another example, the at least one needle 210 may be made of a chemically, acid-, 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 prevent the electrolyte from wetting the positive electrode 111 and / or the negative electrode 113 of the electrode assembly 110.

[0055] 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. As an example, the one end of the at least one needle 210 and the connecting portion 250 may be fixed to each other by a joining method such as welding or adhesive. As another example, the one end of the at least one needle 210 and the connecting portion 250 may have an integrated structure in which they are fixed to each other.

[0056] As a result, in the battery cell manufacturing method according to this embodiment, the needle portion 200 inserted into the electrode assembly 110 in the needle portion inserting step (S200) has a structure in which one end of at least one needle 210 is fixed to the connecting portion 250, which can help fix at least one needle 210 in a predetermined position. Additionally, there is an advantage that at least one needle 210 included in the needle portion 200 can be removed all at once in the subsequent needle portion removing step (S700).

[0057] In addition, the connecting portion 250 may be located 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 located inside the receiving portion 123 together with the electrode assembly 110. Alternatively, if there is not enough space inside the receiving portion 123, the connecting portion 250 may be located outside the receiving portion 123.

[0058] As a result, in the battery cell manufacturing method according to this embodiment, in the needle part insertion step (S200), the connecting portion 250 included in the needle part 200 is positioned between the electrode assembly 110 and the sealing portion 120s, making it possible to easily insert the needle part 200 into the battery cell 100 and easily remove the needle part 200 from the battery cell 100.

[0059] However, the structure of the needle portion 200 is not limited to this, and this embodiment can also include a structure in which the connecting portion 250 is omitted from the needle portion 200, unlike Fig. 3. Furthermore, in the case of a structure in which the connecting portion 250 is omitted from the needle portion 200, at least one needle 210 can be removed in the needle portion removal step (S700) described below.

[0060] 1, the electrolyte injected into the battery cell 100 in the electrolyte injection and sealing step (S300) refers to a liquid electrolyte, and ions can move between the positive electrode and the negative electrode, and the battery cell 100 can be charged and discharged through such ion exchange between the positive electrode and the negative electrode. Examples of the electrolyte include, but are not limited to, organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, and molten inorganic electrolytes.

[0061] Referring to Figures 1 and 2, in the electrolyte injection and sealing step (S300), the battery cell 100 may have the needle portion 200 inserted into the electrode assembly 110, and the electrolyte may be sufficiently injected into the battery case 120, and then the unsealed side of the battery case 120 may be heat-sealed to form the sealing portion 120s.

[0062] Therefore, in the battery cell manufacturing method according to this embodiment, the electrolyte injection and sealing step (S300) sufficiently injects the electrolyte into the inside of the battery cell 100 through one unsealed side of the battery cell 100, and then forms a sealing portion 120s on one unsealed side of the battery cell 100, thereby sealing the internal space of the battery cell 100.

[0063] Fig. 5 is a perspective view showing the battery cell in the degassing and needle part removal step of Fig. 1. Fig. 6 is a perspective view showing the needle removal part and the needle part inserted into the opening of the battery cell of Fig. 5.

[0064] After the electrolyte injection and sealing step (S300), an activation step of activating the battery cell 100; and a degassing and needle part removal step (S700) of removing gas generated inside the battery cell 100 and removing the needle part 200 may be further included.

[0065] 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.

[0066] Here, in the battery cell 100 manufactured by the battery cell manufacturing method according to this embodiment, the activation step is performed with the needle portion 200 inserted inside the electrode assembly 110, so that 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 occur due to such air or gas can be more effectively prevented.

[0067] 1, 2, and 5, in the degassing and needle portion removal step (S700), a portion between the sealing portion 120s of the battery case 120 and the electrode assembly 110 is cut, and 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, and an opening 127 may be formed on one side of the battery cell 100, as shown in FIG.

[0068] Therefore, in the battery cell manufacturing method according to this embodiment, the degassing and needle step (S700) allows air or gas generated inside the battery cell 100 to be discharged to the outside through an opening 127 formed on one side of the battery cell 100.

[0069] 5 and 6, in the degassing and needle portion removal step (S700), the needle removal portion 300 is inserted into the opening 127 to remove the needle portion 200 from the electrode assembly 110. For example, as shown in FIG. 6, the needle removal portion 300 contacts the needle portion 200, and as the needle removal portion 300 moves in a direction toward the opening 127, the needle portion 200 also moves, and the needle portion 200 can be removed from the electrode assembly 110.

[0070] Therefore, in the battery cell manufacturing method according to this embodiment, the degassing and needle portion step (S700) can remove the needle portion 200 from the electrode assembly 110 through the needle removal unit 300 relatively easily.

[0071] Referring to Figures 1 and 2, the method for manufacturing a battery cell according to this embodiment may further include a pressure rolling step (S800) of applying pressure to and rolling the outer surface of the battery cell 100 after the degassing and needle portion removal step (S700).

[0072] Therefore, in the battery cell manufacturing method according to this embodiment, the pressure rolling step (S800) allows air or gas trapped inside the electrode assembly 110 that is not removed in the degassing and needle portion removal step (S700) to be discharged to the outside through the opening 127.

[0073] 1 and 2, the method for manufacturing a battery cell according to this embodiment may include a re-sealing step (S900) of re-sealing the portion cut 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) located adjacent to the receiving portion 123 of the battery case 120 as shown in FIG.

[0074] Therefore, in the battery cell manufacturing method according to this embodiment, the resealing step (S900) can seal the internal space of the battery cell 100 by resealing one side of the battery cell 100 after the air or gas inside the battery cell 100 has been sufficiently removed.

[0075] 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. [Explanation of symbols]

[0076] 100 battery cells 110 Electrode Assembly 111 Positive electrode 113 Negative electrode 115 Separation membrane 120 Battery Case 120s sealing part 123 Storage section 125 outer periphery 127 Opening 150 electrode leads 200 needle part 210 Needle 250 Connection section 300 Needle removal section

Claims

1. a battery cell assembling 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 in a receiving portion of a battery case; a needle portion inserting step of inserting a needle portion into the electrode assembly; and a sealing step of injecting an electrolyte into the battery case while the needle portion is inserted into the electrode assembly, and then forming a sealing portion in the battery case.

2. In the needle portion inserting step, The method of manufacturing a battery cell according to claim 1 , wherein the needle portion is inserted between the separator and the positive electrode that are adjacent to each other, or between the separator and the negative electrode that are adjacent to each other.

3. In the needle portion inserting step, The method of manufacturing a battery cell according to claim 1 , wherein the needle portion is inserted between the separator and the positive electrode adjacent to each other, and between the separator and the negative electrode adjacent to each other.

4. The method for manufacturing a battery cell according to claim 1 , wherein the needle portion is inserted into the center of the electrode assembly.

5. The method of manufacturing a battery cell according to claim 1 , wherein the needle portion includes at least one needle extending along the width direction of the electrode assembly.

6. The method for manufacturing a battery cell according to claim 5, wherein the needle has a thickness of 0.2 mm or more and 1 mm or less.

7. The method of manufacturing a battery cell according to claim 5 , wherein the at least one needle is disposed in a diagonal direction with respect to a thickness direction of the electrode assembly.

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

9. The method of claim 8 , wherein the connecting portion is located between the electrode assembly and the sealing portion.

10. After the electrolyte injection and sealing steps, an activation step of activating the battery cell; and The method for manufacturing a battery cell according to claim 1 , further comprising a degassing and needle portion removal step of removing gas generated inside the battery cell and removing the needle portion.

11. The method of manufacturing a battery cell according to claim 10 , wherein the degassing and needle part removing step involves cutting between the sealing part of the battery case and the electrode assembly, and forming an opening in one side of the battery case.

12. The method for manufacturing a battery cell according to claim 11 , wherein in the degassing and needle portion removing step, a needle remover is inserted into the opening to remove the needle portion from the electrode assembly.

13. After the degassing and needle removal steps, a pressure rolling step of pressing and rolling the outer surface of the battery cell; The method of manufacturing a battery cell according to claim 10 , further comprising a resealing step of resealing a portion cut between the sealing portion of the battery case and the electrode assembly.

14. The activation step comprises: 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 The method for manufacturing a battery cell according to claim 10 , further comprising an aging step of storing the battery cell at a high temperature.

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