Battery cell and method for manufacturing battery cell

Abstract

A battery cell according to an embodiment of the present invention includes: a first outer material comprising a first metal layer and a resin layer attached to an inner surface of the first metal layer; a second outer material comprising a second metal layer; an electrode assembly disposed between the first outer material and the second outer material; an adhesive portion through which the resin layer and the second metal layer are bonded to each other; a folding portion folded such that an edge portion of the second outer material surrounds an edge portion of the first outer material; and a welding portion in which the first metal layer and the second metal layer are welded in the folding portion.

Description

Technical Field

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2024-0053477, filed in Korea on April 22, 2024, the disclosure of which is incorporated herein by reference. Technical Field

[0004] This disclosure relates to a battery cell and a method for manufacturing the battery cell, wherein an electrode assembly is housed between a first outer packaging and a second outer packaging. Background Technology

[0005] Recently, secondary batteries have attracted attention as a power source for electric vehicles (EVs) and hybrid electric vehicles (HEVs), which are being proposed as a solution to the air pollution problems of existing gasoline and diesel vehicles that use fossil fuels.

[0006] Small mobile devices use one or more secondary batteries, while medium and large devices such as electric vehicles use battery modules or battery packs that include multiple secondary batteries electrically connected to each other, due to the need for high output and large capacity.

[0007] Among commercially available rechargeable batteries, lithium-ion batteries are one of the most popular. They can be classified into can-type, prismatic-type, and pouch-type batteries based on the shape of their outer packaging. Pouch-type batteries, in particular, offer high energy density and are easy to stack, making them widely used in medium and large battery modules due to these advantages.

[0008] Recently, with the increasing demand for secondary battery modules installed in vehicles, consumers are increasingly focused on stability. Customers expect and require higher energy density battery cells within the limited space of secondary battery modules, but this also increases the stability risks associated with battery cell ignition and explosion.

[0009] Pouch cell batteries typically have a structure in which electrode assemblies are housed within a pouch cell and a sealing portion is formed at the edge of the cell. When the temperature of the battery cell rises above a critical temperature due to abnormal heating, the rapid increase in temperature and internal pressure can lead to an explosion and subsequent thermal runaway or flame propagation to other adjacent battery cells.

[0010] To prevent or adequately mitigate thermal runaway, sealing components with high heat resistance and sealing strength are required. Summary of the Invention Technical issues

[0011] This disclosure relates to providing a battery cell with a sealed portion having high heat resistance and sealing strength, and a method for manufacturing the battery cell. Technical solution

[0012] A battery cell according to an embodiment of the present disclosure may include: a first outer packaging including a first metal layer and a resin layer attached to an inner surface of the first metal layer; a second outer packaging including a second metal layer; an electrode assembly disposed between the first outer packaging and the second outer packaging; an adhesive portion in which the resin layer and the second metal layer are bonded to each other; a folding portion formed by folding an edge portion of the second outer packaging around an edge portion of the first outer packaging; and a welding portion in which the first metal layer and the second metal layer are welded together in the folding portion.

[0013] The outer surface of the first metal layer can define the outer surface of the first outer packaging, and the inner surface of the second metal layer can define the inner surface of the second outer packaging.

[0014] The welded portion may overlap the adhesive portion in the thickness direction of the first outer packaging component.

[0015] The resin layer may include: a base resin layer; a first adhesive resin layer disposed on one side of the base resin layer and bonded to a first metal layer; and a second adhesive resin layer disposed on the opposite side of the base resin layer and bonded to a second metal layer in an adhesive portion. The adhesive properties of the first and second adhesive resin layers to the metal may be greater than those of the base resin layer to the metal.

[0016] The base resin layer can have lower strain compared to the first adhesive resin layer and the second adhesive resin layer.

[0017] The second metal layer can cover the ends of the resin layer and the first metal layer in the folded portion.

[0018] The folding portion may include: a first folding portion folded to cover the end of the first outer packaging; and a second folding portion connected to the first folding portion and folded to contact the first metal layer. A welded portion may be formed in the second folding portion.

[0019] Each of the first metal layer and the second metal layer may include at least one material selected from stainless steel, copper, and titanium.

[0020] The battery cell may also include an insulating layer covering the outer surfaces of the first metal layer and the second metal layer.

[0021] The battery cell may also include an exhaust guide portion in which the first metal layer and the second metal layer are not welded or are welded with a lower weld strength than the welded portion in the folded portion.

[0022] A method for manufacturing a battery cell according to embodiments of the present disclosure may include the following steps: preparing a first outer package including a first metal layer and a resin layer attached to the inner surface of the first metal layer and a second outer package including a second metal layer; placing an electrode assembly between the first outer package and the second outer package; bonding the resin layer and the second metal layer to each other; forming a folded portion in which an edge portion of the second outer package is folded around an edge portion of the first outer package; and welding the first metal layer and the second metal layer together in the folded portion.

[0023] The method for manufacturing a battery cell may also include the step of attaching or coating an insulating layer to the outer surface of the first metal layer and the second metal layer after the welding step.

[0024] The welding step may include, in part of the folded portion, the first metal layer and the second metal layer being either unwelded or welded with low welding strength. Beneficial effects

[0025] According to an exemplary embodiment of this disclosure, since the battery cell is sealed by welding the metal layers of the first and second outer packaging components, the seal of the battery cell can be maintained under high temperature and high pressure, and has high sealing strength. Therefore, in the event of abnormal operation of the battery cell, an explosion can be delayed, thereby preventing or sufficiently mitigating thermal runaway or flame propagation to other adjacent battery cells.

[0026] In addition, since the metal layers of the first and second outer packaging components are in direct contact within the folded portion, the sealing quality and strength of the welded portion can be improved without the need to remove the resin layer from the outer packaging components.

[0027] Furthermore, the effects of this disclosure may include those readily predictable by those skilled in the art from the configurations of exemplary embodiments according to this disclosure. Attached Figure Description

[0028] The accompanying drawings illustrate exemplary embodiments of the present disclosure and are used, together with the following detailed description, to provide a better understanding of the technical aspects of the present disclosure; therefore, the present disclosure should not be construed as limited to the drawings.

[0029] Figure 1 This is an assembly diagram of a battery cell according to an embodiment of the present disclosure.

[0030] Figure 2 This is a cross-sectional view showing the interior of a battery cell according to an embodiment of the present disclosure.

[0031] Figure 3 This is a plan view of a battery cell according to an embodiment of the present disclosure.

[0032] Figure 4 It shows Figure 2 A variation of the battery cell shown.

[0033] Figure 5 This is a flowchart of a method for manufacturing a battery cell according to another embodiment of the present disclosure. Detailed Implementation

[0034] In the following, exemplary embodiments of the present disclosure will be described in full detail with reference to the accompanying drawings to enable those skilled in the art to readily implement the disclosure. However, the present disclosure may be implemented in many different forms and is not limited to or construed as described below.

[0035] In order to clearly describe this disclosure, irrelevant or detailed descriptions of related known techniques that may unnecessarily obscure the subject matter of this disclosure have been omitted, and throughout the specification, the same or similar reference numerals are added to the same or similar elements when adding reference numerals to the elements in the figures.

[0036] Furthermore, the terms or words used in the specification and appended claims should not be construed as limited to their general and dictionary meanings, but should be interpreted based on their meanings and concepts corresponding to the technical aspects of this disclosure, on the basis of allowing the inventors to appropriately define the terms to obtain the best interpretation.

[0037] In the accompanying drawings, each component of the secondary battery according to an embodiment of the present disclosure is schematically depicted, and for ease of understanding, the dimensions of the components or the thickness of the lines may be slightly exaggerated.

[0038] Figure 1 This is an assembly diagram of a battery cell according to an embodiment of the present disclosure, and Figure 2 This is a cross-sectional view showing the interior of a battery cell according to an embodiment of the present disclosure.

[0039] According to embodiments of the present disclosure, the battery cell 10 may include a first outer packaging 110, a second outer packaging 120, and an electrode assembly 200.

[0040] Electrode assembly 200 may include a positive electrode, a negative electrode, and a spacer inserted between the positive and negative electrodes to insulate them. Electrode assembly 10 is not limited to a particular type. As an example, electrode assembly 200 may be a stacked electrode assembly comprising positive and negative electrodes stacked alternately, with a spacer inserted between them. As another example, electrode assembly 200 may be a wound electrode assembly comprising a sheet-like positive electrode and a sheet-like negative electrode, the sheet-like positive and negative electrodes being wound together with a spacer inserted between them.

[0041] The first outer packaging 110 and the second outer packaging 120 can form a battery box when sealed in a state that contains the electrode assembly 200 and the electrolyte solution.

[0042] The first outer packaging component 110 and the second outer packaging component 120 can each be manufactured as separate components.

[0043] The first outer packaging 110 may include a first metal layer 111 and a resin layer 112 attached to the inner surface of the first metal layer 111. The first outer packaging 110 may be manufactured by forming a laminated sheet including the first metal layer 111 and the resin layer 112.

[0044] The second outer packaging 120 may include a second metal layer 121. The second outer packaging 120 may be manufactured by forming a sheet made of the second metal layer 121. However, the second outer packaging 120 may also include a resin layer (not shown) attached to the outer surface of the second metal layer 121.

[0045] The resin layer 112 can form the innermost layer of the first outer packaging 110. That is, the resin layer 112 can define the inner surface of the first outer packaging 110. The resin layer 112 of the first outer packaging 110 and the second metal layer 121 of the second outer packaging 120 can be bonded to each other to form an adhesive portion 140 as described below.

[0046] More specifically, the resin layer 112 may include a base resin layer 112a, a first adhesive resin layer 112b, and a second adhesive resin layer 112c. The first adhesive resin layer 112b may be disposed on one side of the base resin layer 112a, and the second adhesive resin layer 112c may be disposed on the other side of the base resin layer 112a. More specifically, the first adhesive resin layer 112b and the second adhesive resin layer 112c may be attached to both sides of the base resin layer 112a.

[0047] The base resin layer 112a can have lower strain compared to the first adhesive resin layer 112b and the second adhesive resin layer 112c. Therefore, when heat and pressure are applied to the resin layer 112 to form the adhesive portion 140 as described below, the base resin layer 112a can maintain an appropriate thickness without being excessively compressed.

[0048] The first adhesive resin layer 112b can be bonded to the first metal layer 111. Through the first adhesive resin layer 112b, the first metal layer 111 and the resin layer 112 of the first outer packaging 110 can be kept in an adhesive state.

[0049] The second adhesive resin layer 112c can be bonded to the second metal layer 121. Through the second adhesive resin layer 112c, the resin layer 112 of the first outer packaging 110 and the second metal layer 121 of the second outer packaging 120 can be bonded to each other at the adhesive portion 140 as described below.

[0050] Therefore, the adhesion properties of the first adhesive resin layer 112b and the second adhesive resin layer 112c to the metal can be higher than the adhesion properties of the base resin layer 112a to the metal.

[0051] For example, the base resin layer 112a may comprise polypropylene (PP), and preferably cross-linked PP, random PP, or homogeneous PP. Additionally, the first adhesive resin layer 112b and the second adhesive resin layer 112c may comprise polypropylene grafted with maleic anhydride (PP-g-MA). However, this disclosure is not limited thereto, and those skilled in the art will be able to select suitable materials from known materials that satisfy the required properties of the base resin layer 112a, the first adhesive resin layer 112b, and the second adhesive resin layer 112c.

[0052] The first metal layer 111 can form the outermost layer of the first outer packaging 110. That is, the first metal layer 111 can define the outer surface of the first outer packaging 110.

[0053] The second metal layer 121 can form the innermost layer of the second outer packaging 120. That is, the second metal layer 121 can define the inner surface of the second outer packaging 120.

[0054] Additionally, the first metal layer 111 of the first outer packaging 110 and the second metal layer 121 of the second outer packaging 120 can be welded together to form a welded portion 160 as described below. This will be described in detail below.

[0055] Each of the first metal layer 111 and the second metal layer 121 may include at least one material selected from stainless steel (STS), copper, and titanium. Since stainless steel, copper, and titanium have melting points above 1000°C, the first outer casing 110 and the second outer casing 120 can have high heat resistance compared to aluminum (Al), which typically uses in battery cells and has a melting point of about 660°C.

[0056] Since the second metal layer 121 defines the inner surface of the second outer packaging 120, the second metal layer 121 can directly contact the electrolyte solution contained in the cup-shaped portion C together with the electrode assembly 200.

[0057] In this respect, conventional pouch-type battery cases, including an aluminum layer, suffer from the aluminum layer being exposed to the electrolyte solution when the innermost layer or polymer layer (e.g., polypropylene (PP)) ruptures. Consequently, the aluminum layer carries a negative charge, which accelerates the corrosion of the aluminum-lithium alloy (Al-Li alloy) layer and moisture penetration, leading to battery performance degradation. In contrast, since the second metal layer 121 of this embodiment comprises at least one material selected from stainless steel, copper, and titanium, the aforementioned reaction does not occur when exposed to the electrolyte solution.

[0058] The first outer packaging 110 and the second outer packaging 120 can provide a receiving space in which the electrode assembly 200 can be housed. The first outer packaging 110 and the second outer packaging 120 can have a bag-like shape as a whole, but the shape is not limited to this.

[0059] More specifically, at least one of the first outer packaging 110 or the second outer packaging 120 may have a cup-shaped portion C in which the electrode assembly 200 may be accommodated. The cup-shaped portion C having a concave shape may define a receiving space in which the electrode assembly 200 may be accommodated.

[0060] In the following text, such as Figure 1 and Figure 2 The illustration describes by way of example a first outer packaging 110 having a cup-shaped portion C and a second outer packaging 120 covering the cup-shaped portion C of the first outer packaging 110. However, this disclosure is not limited thereto. The second outer packaging 120 may have a cup-shaped portion C, and the first outer packaging 110 may cover the cup-shaped portion C of the second outer packaging 120. Alternatively, each of the first outer packaging 110 and the second outer packaging 120 may have a cup-shaped portion C, and the two cup-shaped portions C may be connected to each other to define a receiving space in which the electrode assembly 200 may be received.

[0061] The first outer packaging 110 and the second outer packaging 120 may each include edge portions 110A and 120A, respectively. The edge portions 110A and 120A may be referred to as platform portions.

[0062] The edge portion 110A of the first outer packaging 110 may refer to the area surrounding the cup-shaped portion C. The edge portion 120A of the second outer packaging 120 may refer to the area facing the edge portion 110A of the first outer packaging 110 and its outer area.

[0063] The edge portion 110A of the first outer packaging 110 and the edge portion 120A of the second outer packaging 120 can be sealed to each other, and thus the electrode assembly 200 can be accommodated between the first outer packaging 110 and the second outer packaging 120.

[0064] Meanwhile, the battery unit 10 may include a folded portion 150 formed by folding the edge portion 120A of the second outer packaging 120 around the edge portion 110A of the first outer packaging 110.

[0065] More specifically, the edge portion 120A of the second outer packaging 120 may be folded along the end of the edge portion 110A of the first outer packaging 110. For this purpose, the edge portion 120A of the second outer packaging 120 may be wider than the edge portion 110A of the first outer packaging 110. More specifically, the edge portion 120A of the second outer packaging 120 may be longer than the edge portion 110A of the first outer packaging 110 in both the length and width directions.

[0066] The folded portion 150 can be formed along the periphery of the battery cell 10.

[0067] Figure 1 The first line L1 and the second line L2 shown are illustrated as fold lines of the edge portion 120A of the second outer packaging 120.

[0068] The first line L1 may be parallel to the length direction of the battery cell 10, and the second line L2 may be parallel to the width direction of the battery cell 10. The first line L1 and the second line L2 may be matched with the end of the edge portion 110A of the first outer packaging 110.

[0069] The first line L1 and the second line L2 can be folded in a certain order or in reverse order. The corner portion where the first line L1 and the second line L2 overlap at the edge portion 120A of the second outer packaging 120 can be double-folded. However, this disclosure is not limited thereto, and those skilled in the art will be able to customize the corner portion into a suitable shape.

[0070] In the folded portion 150, the second metal layer 121 may cover the ends of the resin layer 112 and the first metal layer 111.

[0071] More specifically, the folding portion 150 may include a first folding portion 151 and a second folding portion 152, the first folding portion 151 being folded to cover the end of the first outer packaging 110, and the second folding portion 152 being connected to the first folding portion 151 and folded to contact the first metal layer 111.

[0072] The first fold portion 151 can be formed by folding a portion of the outer portion of the edge portion 120A of the second outer packaging 120. The end of the first outer packaging 110 can face the inner surface of the first fold portion 151.

[0073] The end of the first outer packaging 110 may contact or be adjacent to the inner surface of the first folded portion 151. However, this disclosure is not limited thereto, and a predetermined gap may be formed between the end of the first outer packaging 110 and the inner surface of the first folded portion 151.

[0074] The second fold portion 152 can be formed by folding a portion of the outer part of the first fold portion 151. The inner surface of the second fold portion 152 can contact the outer surface of the edge portion 110A of the first outer packaging 110. Therefore, the second metal layer 121 forming the inner surface of the second fold portion 152 can contact the first metal layer 111 forming the outer surface of the first outer packaging 110. Here, the first metal layer 111 and the second metal layer 121 that are in contact with each other can be welded together to form a welded portion 160 as described below. That is, the welded portion 160 can be formed in the second fold portion 152.

[0075] Meanwhile, the battery cell 10 may include an adhesive portion 140 and a welded portion 160.

[0076] The adhesive portion 140 can be formed by bonding the resin layer 112 of the first outer packaging 110 and the second metal layer 121 of the second outer packaging 120 to each other. More specifically, the resin layer 112 of the edge portion 110A of the first outer packaging 110 can be bonded to the second metal layer 121 of the edge portion 120A of the second outer packaging 120 to form the adhesive portion 140. More specifically, the second adhesive resin layer 112c of the edge portion 110A of the first outer packaging 110 can be bonded to the second metal layer 121 of the edge portion 120A of the second outer packaging 120 to form the adhesive portion 140. The adhesive portion 140 can be formed by heat fusion, but is not limited thereto.

[0077] The adhesive portion 140 may be positioned further inward than the folded portion 150. The adhesive portion 140 may extend along the edge portion 110A of the first outer packaging 110 and the edge portion 120A of the second outer packaging 120.

[0078] The welded portion 160 can be formed by welding the first metal layer 111 and the second metal layer 121 in the folded portion 150. More specifically, the first metal layer 111 and the second metal layer 121 that are in contact with each other in the second folded portion 152 can be welded together to form the welded portion 160. The welded portion 160 can be formed by laser welding, but is not limited thereto.

[0079] Since the metal layers 111 and 121 are welded together, the welded portion 160 can have a higher sealing strength than the adhesive portion 140. Therefore, the sealing strength of the battery cell 10 can be significantly improved.

[0080] The welded portion 160 may extend along the folded portion 150. The welded portion 160 may be formed along the periphery of the battery cell 10.

[0081] The welded portion 160 may overlap with the adhesive portion 140 in the thickness direction of the first outer packaging 110. The welded portion 160 and the adhesive portion 140 may face each other, with the edge portion 110A of the first outer packaging 110 interposed between them. More specifically, the adhesive portion 140 may be formed on the inner surface of the edge portion 110A of the first outer packaging 110, and the welded portion 160 may be formed on the outer surface.

[0082] As described above, the first metal layer 111 can define the outer surface of the first outer packaging 110, and the second metal layer 121 can define the inner surface of the second outer packaging 120. Therefore, the first metal layer 111 and the second metal layer 121 can be in direct contact with each other in the folded portion 150, and high sealing quality and strength of the welded portion 160 can be achieved.

[0083] In this regard, it is well known that conventional laminated sheets comprise two polymer layers (e.g., polypropylene (PP) and polyethylene terephthalate (PET)) forming an outer and an inner surface, and a metal layer (e.g., aluminum (Al)) interposed between the two polymer layers. Assuming the first and second outer packaging components are manufactured by forming existing laminated sheets, in a folded portion where the edge portion of the second outer packaging component folds around the edge portion of the first outer packaging component, the polymer layer is disposed between the first metal layer of the first outer packaging component and the second metal layer of the second outer packaging component. Therefore, when the first and second metal layers are welded together in the folded portion, the weldability deteriorates due to the polymer layer. To address this problem, a welding process can be performed to weld the first and second metal layers together after a removal process that removes the polymer layer from the edge portions of the first and second outer packaging components, but this complicates the manufacturing process of the battery cell. In contrast, the battery cell 1 of this embodiment does not require a removal process.

[0084] Figure 3 This is a plan view of a battery cell according to an embodiment of the present disclosure.

[0085] The battery cell 10 may also include an exhaust guide portion 170, where the first metal layer 111 and the second metal layer 121 are not welded or are welded with a lower weld strength than the welded portion 160 in the folded portion 150.

[0086] The exhaust guide portion 170 may be provided at the folded portion 150. More specifically, along the periphery of the battery cell 10, the welding portion 160 may be provided at a portion of the folded portion 150, and the exhaust guide portion 170 may be provided at another portion of the folded portion 150.

[0087] The exhaust guide portion 170 may include at least one exhaust guide portion 170 along the periphery of the battery cell 10. By adjusting the length, number, or position of the exhaust guide portion 170, the degree of gas exhaust in the battery cell 10 can be easily and appropriately designed.

[0088] Because the sealing strength of the adhesive portion 140 is lower than that of the welded portion 160, the adhesive portion 140 can rupture when the internal pressure of the battery cell 10 rises above a predetermined level. In this case, the gas in the battery cell 10 can be released to the outside of the battery cell 10 through the exhaust guide portion 170.

[0089] When the exhaust guide portion 170 is formed by a non-welding method through the first metal layer 111 and the second metal layer 121 in the folded portion 150, the gas in the battery cell 10 can be released to the outside of the battery cell 10 through the space between the first metal layer 111 and the second metal layer 121 of the exhaust guide portion 170.

[0090] When the exhaust guide portion 170 is formed by welding the first metal layer 111 and the second metal layer 121 in the folded portion 150 with low welding strength, the welded portion with low welding strength may break when the internal pressure of the battery cell 10 rises, and the gas in the battery cell 10 can be released to the outside of the battery cell 10 through the space between the first metal layer 111 and the second metal layer 121 of the exhaust guide portion 170.

[0091] The exhaust guide section 170 can achieve directional exhaust to release gas in a preset direction. Therefore, it can prevent the explosion of the battery cell 10 and the resulting thermal runaway or flame propagation to other adjacent battery cells.

[0092] Figure 4 It shows Figure 2 A variation of the battery cell shown.

[0093] The battery cell 10 may also include an insulating layer 130 covering the outer surfaces of the first metal layer 111 and the second metal layer 121.

[0094] The insulating layer 130 can be formed after the weld portion 160 is formed. The insulating layer 130 can be attached to or coated on the outer surfaces of the first metal layer 111 and the second metal layer 121. Through the insulating layer 130, the battery cell 10 can remain insulated from other adjacent battery cells or components.

[0095] Figure 5 This is a flowchart of a method for manufacturing a battery cell according to another embodiment of the present disclosure.

[0096] In the following, the method for manufacturing the battery cell 10 described above, as another embodiment of this disclosure, will be described.

[0097] A method for manufacturing a battery cell according to another embodiment of the present disclosure may include the following steps: (S10) preparing a first outer packaging 110 including a first metal layer 111 and a resin layer 112 and a second outer packaging 120 including a second metal layer 121 (hereinafter, preparation step); (S20) placing an electrode assembly 200 between the first outer packaging 110 and the second outer packaging 120 (hereinafter, receiving step); (S30) bonding the resin layer 112 and the second metal layer 121 to each other (hereinafter, bonding step); (S40) forming a folded portion 150, wherein an edge portion 120A of the second outer packaging 120 is folded around an edge portion 110A of the first outer packaging 110 (hereinafter, folding step); and (S50) welding the first metal layer 111 and the second metal layer 121 in the folded portion 150 (hereinafter, welding step).

[0098] In the preparation step (S10), a recessed cup-shaped portion C may be formed in at least one of the first outer packaging 110 or the second outer packaging 120. In addition, the edge portion 120A of the second outer packaging 120 may be wider than the edge portion 110A of the first outer packaging 110.

[0099] In the receiving step (S20), with the electrode assembly 200 received in the cup-shaped portion C, the edge portions 110A of the first outer packaging 110 and the edge portions 120A of the second outer packaging 120 can contact each other. Therefore, the electrode assembly 200 can be received between the first outer packaging 110 and the second outer packaging 120. In this case, the edge portion 120A of the second outer packaging 120 can protrude from the edge portion 110A of the first outer packaging 110.

[0100] In the bonding step (S30), the resin layer 112 of the edge portion 110A of the first outer packaging 110 can be bonded to the second metal layer 121 of the edge portion 120A of the second outer packaging 120. For this purpose, the edge portion 110A of the first outer packaging 110 and the edge portion 120A of the second outer packaging 120 can undergo heat fusion while in contact with each other.

[0101] In the folding step (S40), the edge portion 120A of the second outer packaging 120 can be folded around the end of the edge portion 110A of the first outer packaging 110, and a folded portion 150 can be formed. The first metal layer 111 and the second metal layer 121 can contact each other in the folded portion 150.

[0102] In the welding step (S50), the first metal layer 111 and the second metal layer 121 can be welded together in the folded portion 150 to form a welded portion 160. The welded portion 160 can be formed along the periphery of the battery cell 10.

[0103] In the welding step (S50), the first metal layer 111 and the second metal layer 121 may be left unwelded or welded with low welding strength in a portion of the folded portion 150, and an exhaust guide portion 170 may be formed. A weld with low welding strength refers to a seal strength lower than that of the welded portion 160. More specifically, along the peripheral direction of the battery cell 10, the welded portion 160 may be formed in a portion of the folded portion 150, and the exhaust guide portion 170 may be formed in another portion.

[0104] Despite Figure 5 Although not shown, the method for manufacturing a battery cell may further include attaching or coating an insulating layer 130 to or onto the outer surfaces of the first metal layer 111 and the second metal layer 121. This step may be performed after the welding step (S50). Therefore, the insulating layer 130 can prevent a reduction in the sealing quality of the welded portion 160 and reliably insulate the battery cell 10 from other components.

[0105] The foregoing description has illustrated the technical aspects of this disclosure by way of example, and those skilled in the art to which this disclosure pertains will be able to make various modifications and changes without departing from the essential characteristics of this disclosure.

[0106] Therefore, the disclosed embodiments are provided to describe the technical aspects of this disclosure and are not intended to be limiting, and the technical scope of this disclosure is not limited by these embodiments.

[0107] The scope of protection of this disclosure shall be interpreted by the appended claims, and shall be interpreted as including all technical aspects within the equivalent scope within the scope of protection of this disclosure.

[0108] [List of reference numerals]

[0109] 10: Battery unit 110: First outer packaging

[0110] 111: First metal layer; 112: Resin layer

[0111] 112a: Base resin layer; 112b: First adhesive resin layer

[0112] 112c: Second adhesive resin layer; 120: Second outer packaging component

[0113] 121: Second metal layer; 130: Insulating layer

[0114] 140: Adhesive part; 150: Folded part

[0115] 151: First fold section 152: Second fold section

[0116] 160: Welding section; 170: Exhaust guide section

[0117] 200: Electrode assembly

Claims

1. A battery cell, comprising: A first outer packaging component, the first outer packaging component including a first metal layer and a resin layer attached to the inner surface of the first metal layer; The second outer packaging component includes a second metal layer; An electrode assembly, the electrode assembly being housed between the first outer packaging and the second outer packaging; An adhesive portion in which the resin layer and the second metal layer are bonded together; The folding portion is formed by folding the edge portion of the second outer packaging component around the edge portion of the first outer packaging component; as well as In the welding section, the first metal layer and the second metal layer are welded together in the folded section.

2. The battery cell according to claim 1, in, The outer surface of the first metal layer defines the outer surface of the first outer packaging component, and The inner surface of the second metal layer defines the inner surface of the second outer packaging.

3. The battery cell according to claim 1, in, The welded portion overlaps with the adhesive portion in the thickness direction of the first outer packaging component.

4. The battery cell according to claim 1, in, The resin layer comprises: Base resin layer; A first adhesive resin layer, wherein the first adhesive resin layer is disposed on one side of the base resin layer and bonded to the first metal layer; and A second adhesive resin layer is disposed on the opposite side of the base resin layer and bonded to the second metal layer in the adhesive portion. The adhesion properties of the first adhesive resin layer and the second adhesive resin layer to the metal are higher than those of the base resin layer to the metal.

5. The battery cell according to claim 4, in, The base resin layer has lower strain compared to the first adhesive resin layer and the second adhesive resin layer.

6. The battery cell according to claim 1, in, The second metal layer covers the ends of the resin layer and the first metal layer in the folded portion.

7. The battery cell according to claim 1, in, The folded portion includes: A first fold portion, the first fold portion being folded to cover the end of the first outer packaging; and The second fold portion is connected to the first fold portion and is folded to contact the first metal layer, and The welded portion is formed in the second folded portion.

8. The battery cell according to claim 1, in, Each of the first metal layer and the second metal layer comprises at least one material selected from stainless steel, copper, and titanium.

9. The battery cell according to claim 1, further comprising: An insulating layer that covers the outer surfaces of the first metal layer and the second metal layer.

10. The battery cell according to claim 1, further comprising: The exhaust guide section, in which the first metal layer and the second metal layer are not welded or are welded with a lower welding strength than the welded portion in the folded portion.

11. A method for manufacturing a battery cell, comprising the following steps: Prepare a first outer packaging comprising a first metal layer and a resin layer attached to the inner surface of the first metal layer, and a second outer packaging comprising a second metal layer; The electrode assembly is placed between the first outer packaging and the second outer packaging; The resin layer and the second metal layer are bonded together; A folded portion is formed, wherein the edge portion of the second outer packaging is folded around the edge portion of the first outer packaging; as well as The first metal layer and the second metal layer are welded together in the folded portion.

12. The method for manufacturing a battery cell according to claim 11, further comprising the following step after the welding step: The insulating layer is attached or coated onto the outer surfaces of the first metal layer and the second metal layer.

13. The method for manufacturing a battery cell according to claim 11, in, The welding step includes: in a portion of the folded portion, the first metal layer and the second metal layer are not welded or are welded with low welding strength.

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