Secondary battery and manufacturing method therefor

Abstract

A secondary battery according to an embodiment of the present invention may comprise: an electrode assembly; a battery case comprising an accommodation part for accommodating the electrode assembly and a side part located outside the accommodation part and folded at least once; and a fixing member attached to the battery case and fixing the side part in a folded state. A tear line may be formed on the fixing member so as to be easily broken when an external force is applied to the fixing member.

Description

Secondary battery and manufacturing method thereof

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0133675, filed October 6, 2023, and Korean Patent Application No. 10-2024-0008148, filed January 18, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a secondary battery and a method for manufacturing the same, and more particularly, to a secondary battery in which a terrace portion folded at least once is fixed by a fixing member, and a method for manufacturing the same.

[0005] Unlike primary batteries, secondary batteries can be recharged and discharged, making them suitable for a wide range of applications, including digital cameras, mobile phones, laptops, and hybrid vehicles. Examples of secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-hydrogen batteries, and lithium secondary batteries.

[0006] Among these secondary batteries, much research is being conducted on lithium secondary batteries with high energy density and discharge voltage, and recently, lithium secondary batteries are manufactured as flexible pouch-type secondary batteries and are used by connecting multiple batteries to form a module.

[0007] Secondary batteries can use various types of battery cases as an outer covering for the electrode assembly, for example, a pouch-type battery case or a can-type battery case can be used. The electrode assembly has a structure in which a positive electrode plate and a negative electrode plate filled with an electrode active material and a separator interposed between the positive electrode plate and the negative electrode plate are laminated. A positive electrode tab is formed on one side of the positive electrode plate, and a negative electrode tab is formed on one side of the negative electrode plate. The tabs are connected to electrode leads, thereby connecting to an external circuit. This electrode assembly is sealed by the battery case, which is an outer covering.

[0008] The battery case may include a receiving portion for receiving the electrode assembly and a terrace portion positioned around the receiving portion for sealing the electrode assembly. In addition, some of the terrace portions may be foldable to increase energy density.

[0009] For example, the terrace portion may be single-side folded (SSF) or double-side folded (DSF). Since the terrace portion may not remain folded for a certain period of time and may partially unfold and protrude outward, a fixing member such as tape may be used to fix the terrace portion in the folded state to prevent this.

[0010] However, when flames or gases are generated due to abnormal operation of the secondary battery, there is a problem in that the flames or gases are not discharged toward the folded terrace portion due to the fixing member, but rather discharged toward the electrode leads.

[0011] Within a battery module or battery pack, if a flame or gas generated from one battery cell is discharged toward the electrode lead, the flame may rapidly spread to the surrounding area, causing continuous thermal runaway of adjacent battery cells. Therefore, a solution to this problem is required.

[0012] The problem to be solved by the present invention is to provide a secondary battery capable of quickly venting flames or gases and a method for manufacturing the same.

[0013] A secondary battery according to an embodiment of the present invention may include: an electrode assembly; a battery case including a receiving portion for receiving the electrode assembly, a side portion positioned outside the receiving portion and folded at least once; and a fixing member attached to the battery case and fixing the side portion in a folded state. A cutting line may be formed on the fixing member so that the fixing member is easily broken when an external force is applied to the fixing member.

[0014] The above-mentioned cutting line can be formed by forming holes in the fixing member at predetermined intervals in one direction.

[0015] The above-mentioned cutting line can be formed long in the longitudinal direction of the side portion.

[0016] In the above-mentioned fixed member, a sub-cut line formed long in a direction intersecting the above-mentioned cutting line may be further formed.

[0017] The above sub-cut lines can be formed at predetermined intervals in the extension direction of the above cut lines.

[0018] The above-mentioned cutting line may be formed at a position corresponding to the gap or boundary between the receiving portion and the side portion.

[0019] The above-mentioned fixing member may include a first adhesive portion adhered to the receiving portion; a second adhesive portion adhered to the side portion; and a connecting portion connecting the first adhesive portion and the second adhesive portion.

[0020] The above-mentioned cutting line can be formed in the above-mentioned connecting portion.

[0021] The above connecting portion may include a first connecting portion located on the side where the side portion is folded and having the cut line formed thereon; and a second connecting portion located on the opposite side of the first connecting portion with respect to the second adhesive portion.

[0022] A method for manufacturing a secondary battery according to an embodiment of the present invention may include the steps of folding a side portion of a battery case containing an electrode assembly at least once; preparing a fixing member having a cut line formed along a preset direction; and attaching the fixing member to the battery case so that the side portion is fixed in a folded state.

[0023] In the step of attaching the above-mentioned fixing member, the fixing member can be attached so that the cutting line is parallel to the longitudinal direction of the side portion.

[0024] In the step of attaching the above-mentioned fixing member, the fixing member may be attached so that the cut line corresponds to the gap or boundary between the receiving portion in which the electrode assembly is received and the side portion.

[0025] According to a preferred embodiment of the present invention, when a fire occurs inside a secondary battery, the fixing member fixing the side portion can be easily broken, and gas and flames can be quickly vented through the side portion whose seal has been released.

[0026] Additionally, during normal operation of the secondary battery, the side portion can be reliably maintained in a folded state by the fixing member.

[0027] Additionally, it can prevent or delay the venting of gas or flame toward the electrode leads. Therefore, in a battery module, it can minimize the rapid propagation of flames to the surrounding area, which can cause continuous thermal runaway of adjacent secondary batteries.

[0028] In addition, the configurations according to preferred embodiments of the present invention may include effects that can be easily predicted by those skilled in the art.

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

[0030] Figure 1 is an exploded view of a secondary battery according to one embodiment of the present invention.

[0031] Figure 2 is a plan view of a secondary battery according to one embodiment of the present invention.

[0032] Figure 3 is a cross-sectional view taken along line A-A' of Figure 2.

[0033] Figure 4 is a plan view of a secondary battery according to another embodiment of the present invention.

[0034] Figure 5 is a flowchart of a secondary battery manufacturing method according to another embodiment of the present invention.

[0035] Hereinafter, with reference to the attached drawings, preferred embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be implemented in various different forms and is not limited or restricted by the following examples.

[0036] In order to clearly explain the present invention, a detailed description of a part that is irrelevant to the description or a related known technology that may unnecessarily obscure the gist of the present invention has been omitted, and when adding reference signs to components of each drawing in this specification, the same or similar reference signs are attached to the same or similar components throughout the specification.

[0037] In addition, terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0038] In the drawing, each component of a secondary battery according to one embodiment of the present invention is schematically illustrated, and the size of the component or the thickness of the line may be expressed somewhat exaggerated for the convenience of understanding.

[0039] FIG. 1 is an exploded view of a secondary battery according to one embodiment of the present invention, FIG. 2 is a plan view of a secondary battery according to one embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along line A-A' of FIG. 2.

[0040] A secondary battery (1) according to one embodiment of the present invention may include an electrode assembly (10) and a battery case (20). Hereinafter, as illustrated in the drawing, the description will be based on the case where the battery case (20) is a pouch-type battery case. However, the scope of the present invention is not limited thereto.

[0041] The electrode assembly (10) may be formed by alternately stacking positive and negative electrodes with a separator in between. That is, the electrode assembly (10) may include a plurality of electrodes and a separator interposed between the plurality of electrodes to mutually insulate the plurality of electrodes. The electrode assembly (10) may be accommodated together with an electrolyte in a battery case (20), more specifically, in a receiving portion (22) described below.

[0042] The electrode assembly (10) can be provided in various types, such as stack type, jelly roll type, stack and folding type, and the type of the electrode assembly (10) is not limited.

[0043] The electrode assembly (10) may include an electrode tab (11). The electrode tab (11) is connected to the positive and negative electrodes of the electrode assembly (10), respectively, and may protrude outward from the electrode assembly (10) to act as a path through which electrons can move between the inside and the outside of the electrode assembly (10).

[0044] The electrode tab (11) can be formed by cutting the non-conductive part of the electrode collector or by connecting a separate conductive member to the non-conductive part by ultrasonic welding, etc.

[0045] The electrode tab (11) may include a positive tab (111) connected to the positive electrode, and a negative tab (112) connected to the negative electrode. The positive tab (111) and the negative tab (112) may protrude in different directions of the electrode assembly (10), but are not limited thereto, and may be formed to protrude in various directions, such as protruding in parallel in the same direction from one side.

[0046] An electrode lead (12) for supplying electricity to the outside of the secondary battery (1) may be connected to the electrode tab (11) of the electrode assembly (10). In addition, a portion of the electrode lead (12) may be surrounded by an insulating portion (14). The insulating portion (14) may be sealed together with the first case (21) and the second case (22). Therefore, the insulating portion (14) may insulate the electrode lead (12) from the battery case (20) and maintain the sealing of the battery case (20). In general, as the insulating portion (14), an insulating tape that is easy to attach to the electrode lead (12) and has a relatively thin thickness is often used, but the present invention is not limited thereto and various materials may be used as long as the electrode lead (12) can be insulated.

[0047] The electrode lead (12) may have one end connected to the electrode tab (11) and the other end protruding outward from the battery case (13). The electrode lead (12) may include a positive lead (121) connected to the positive tab (111) and a negative lead (122) connected to the negative tab (112).

[0048] The electrode lead (12) can electrically connect the electrode assembly (10) to the outside. In addition, since the positive electrode tab (111) and the negative electrode tab (112) are formed to protrude in various directions, the positive electrode lead (121) and the negative electrode lead (122) can also extend in various directions, respectively.

[0049] The battery case (20) can accommodate an electrode assembly (10) therein. In particular, a pouch-shaped battery case can be formed by molding a laminate sheet. More specifically, when a flexible laminate sheet is subjected to drawing molding using a die, a punch, or the like, a portion thereof is stretched to form a receiving portion (22) having a pocket-shaped receiving space, thereby manufacturing the battery case (20).

[0050] The battery case (20) can accommodate and seal the electrode assembly (10) so that a portion of the electrode lead (12) is exposed.

[0051] The battery case (20) may include a receiving portion (22) and a terrace portion (23) (26) located on the outside of the receiving portion (22).

[0052] In more detail, the battery case (20) may include a first case (20a) and a second case (20b), and a receiving portion (22) may be formed in at least one of the first case (20a) and the second case (20b). In addition, a peripheral area of ​​the receiving portion (22) may form a terrace portion (23) (26).

[0053] The first case (20a) and the second case (20b) can be connected to each other by the folding part (21). However, this is not limited to this, and it is also possible for the first case (20a) and the second case (20b) to be separated from each other and manufactured separately.

[0054] The receiving portion (22) can define a receiving space capable of receiving the electrode assembly (10). The receiving portion (22) can have a pocket shape.

[0055] Hereinafter, a case in which a receiving portion (22) is formed in each of the first case (20a) and the second case (20b) will be described as an example. Those skilled in the art will also be able to easily understand a case in which a receiving portion (22) is formed in only one of a pair of cases (20a) (20b).

[0056] The receiving portions (22) of a pair of cases (20a) (20b) are arranged to face each other, so that they can accommodate the electrode assembly (10) together. That is, the receiving portions (22) of a pair of cases (20a) (20b) are arranged to face each other, so that they can define a receiving space in which the electrode assembly (10) is accommodated. In this case, compared to a case in which the receiving portion (22) is formed in only one of the pair of cases (20a) (20b), the electrode assembly (20) can accommodate an electrode assembly (10) that is thick and has a large capacity.

[0057] The first case (20a) and the second case (20b) can be connected by a folding part (21). When the first case (20a) and the second case (20b) are unfolded, a part of the folding part (21) can be positioned between the receiving part (22) of the first case (20a) and the receiving part (22) of the second case (20b), and another part of the folding part (21) can be positioned between the terrace part (23)(26) of the first case (20a) and the terrace part (23)(26) of the second case (20b).

[0058] When the folding part (21) is folded, the first case (20a) and the second case (20b) can face each other. The folding part (21) can extend parallel to the electric length direction of the electrode assembly (10), but is not limited thereto.

[0059] Each case (20a) (20b) may include a terrace portion (23) (26) located around the periphery of the receiving portion (22). More specifically, the terrace portion (23) (26) may include a first terrace portion (23) from which the electrode lead (12) protrudes, and a second terrace portion (26) that is folded at least once.

[0060] For example, as illustrated in FIGS. 1 and 2, a pair of first terrace sections (23) may be provided on opposite sides of the receiving section (22) in the full-length direction, and a second terrace section (26) may be provided to connect a pair of first terrace sections (23) and may be positioned on one side of the receiving section (22) in the full-width direction. In this case, the first terrace section (23) may extend in the full-width direction of the receiving section (22), and the second terrace section (26) may extend in the full-length direction of the receiving section (22).

[0061] As another example, if the first case (20a) and the second case (20b) are separate members that are not connected by the folding part (21), a pair of first terrace parts (23) may be provided located on both sides in the full-length direction of the receiving part (22), and a pair of second terrace parts (26) may be provided that connect a pair of first terrace parts (23) and are located on both sides in the full-width direction of the receiving part (22).

[0062] When the first case (20a) and the second case (20b) are connected by the folding part (21), either the first terrace part (23) or the second terrace part (26) may be located on the opposite side of the folding part (21) with respect to the receiving part (22).

[0063] For example, as illustrated in FIGS. 1 and 2, the second terrace portion (26) may be positioned on the opposite side of the folding portion (21) with respect to the receiving portion (22). In this case, a pair of first terrace portions (23) may connect the folding portion (21) and the second terrace portion (26). That is, a pair of electrode leads (12) may extend in opposite directions and protrude outward through each of the first terrace portions (23).

[0064] As another example, it is also possible for the first terrace portion (26) to be positioned on the opposite side of the folding portion (21) with respect to the receiving portion (22). That is, a pair of electrode leads (12) may extend in a direction away from the folding portion (21) in parallel with each other and protrude outward through the first terrace portion (23). In this case, a pair of second terrace portions (26) may be provided, and may connect the folding portion (21) and the first terrace portion (23).

[0065] In this way, the extension direction and position of the first terrace section (23) and the second terrace section (26) are not limited and can be formed differently as needed.

[0066] When the folding portion (21) is folded, the terrace portions (23) (26) of the first case (20a) and the second case (20b) can be in contact with each other. At this time, the insulating portion (14) of the electrode assembly (10) can be positioned between the terrace portions (23) (26) of the pair of cases (20a) (20b). For example, the insulating portion (14) can be positioned between the first terrace portions (23) of the pair of cases (20a) (20b).

[0067] The terrace portions (23) (26) of the first case (20a) and the second case (20b) can be sealed to each other. The first terrace portions (23) of the first case (20a) and the second case (20b) can be sealed to each other, and a portion thereof can be sealed to the insulating portion (14). The second terrace portions (26) of the first case (20a) and the second case (20b) can be sealed to each other.

[0068] At least a portion of the sealed terrace portion (23)(26) can be folded at least once. More specifically, the second terrace portion (26) can be folded at least once. The second terrace portion (26) can be SSF (Single Side Folding) or DSF (Double Side Folding). Hereinafter, the second terrace portion (26) is referred to as a side portion, but is indicated by the same drawing reference numeral '26'.

[0069] The secondary battery (1) may include a fixing member (30).

[0070] The fixing member (30) is attached to the battery case (20) and can fix the side portion (26) in a folded state. For example, the fixing member (30) may be a tape.

[0071] In the present embodiment, a plurality of fixing members (30) may be provided. The plurality of fixing members (30) may be arranged to have a predetermined interval from each other in the longitudinal direction of the side portion (30). The lengths of the plurality of fixing members (330) may be the same, but are not limited thereto.

[0072] Referring to FIG. 4, each fixing member (30) may include a first adhesive portion (31) bonded to the receiving portion (22), a second adhesive portion (32) bonded to the side portion (26), and a connecting portion (33) connecting the first adhesive portion (31) and the second adhesive portion (32).

[0073] The first adhesive portion (31) may be located at the end of the fixing member (30). The first adhesive portion (31) may be bonded to the bottom surface (221) of the receiving portion (22).

[0074] The second adhesive portion (32) can be adhered to the outer side of the side portion (26).

[0075] The connecting portion (33) may be located between the first adhesive portion (31) and the second adhesive portion (32). The cutting line (40) described later may be formed in the connecting portion (33).

[0076] As illustrated in Fig. 4, both ends of the fixing member (30) can be bonded to each receiving portion (22). The side portion (26) can be folded toward one receiving portion (22). In this case, a pair of first adhesive portions (31) can be provided, and a pair of connecting portions (33) can also be provided. More specifically, one of the pair of first adhesive portions (31) can be bonded to one receiving portion (22), and the other can be bonded to the other receiving portion (22).

[0077] The connecting portion (33) may include a first connecting portion (33A) and a second connecting portion (33B). The first connecting portion (33A) may connect one of the pair of first adhesive portions (31) and the second adhesive portion (32). The first connecting portion (33A) may be located on the side where the side portion (26) is folded. A cutting line (40), which will be described later, may be formed on the first connecting portion (33A). The second connecting portion (33B) may connect the other of the pair of first adhesive portions (31) and the second adhesive portion (32). The second connecting portion (33B) may be located on the opposite side of the first connecting portion (33A) with respect to the second adhesive portion (32). A cutting line (40), which will be described later, may also be formed on the second connecting portion (33B).

[0078] However, unlike as shown in Fig. 4, one end of the fixing member (30) may be bonded to one receiving portion (22), and the other end may be bonded to the side portion (26). That is, the first adhesive portion (31) may be located at one end of the fixing member (30), and the second adhesive portion (32) may be located at the other end of the fixing member (30). In this case, the connecting portion (33) may be located on the side where the side portion (26) is folded.

[0079] Meanwhile, if ignition occurs in the electrode assembly (10), the battery case (20) may be damaged and gas may be discharged along with sparks or particles. In this case, if the gas is discharged toward the electrode lead (12), there is a concern that heat and flames may spread quickly to other secondary batteries in the vicinity. To alleviate this concern, it is preferable that the sealing is first destroyed on the side portion (26) to vent the gas, but the fixing member (30) may hinder this.

[0080] To solve this problem, a cutting line (40) may be formed on the fixing member (30) so that the fixing member (30) can be easily broken when an external force is applied to the fixing member (30).

[0081] In the present embodiment, a cutting line (40) may be formed on at least one of the plurality of fixing members (30). Preferably, a cutting line (40) may be formed on each fixing member (30).

[0082] When high-temperature gas is generated due to abnormal operation of the electrode assembly (10), the pressure inside the battery case (20) increases. At this time, an external force may be applied to the fixing member (30) during the process of unfolding the folded side portion (26). That is, tension is applied to the fixing member (30). When a certain level or more of external force is applied to the fixing member (30), the portion along the cut line (40) may be preferentially broken. As a result, the side portion (26) can unfold, the sealing of the side portion (26) is released, and the gas and flame inside the battery case (20) can be quickly discharged.

[0083] The cutting line (40) may be formed to be long in the longitudinal direction of the side portion (26) (e.g., in the direction of the entire length of the receiving portion (22)). The cutting line (40) may extend from one edge of the fixing member (30) to the opposite edge.

[0084] The cutting line (40) may be formed by forming holes (41) in the fixing member (30) at predetermined intervals in one direction. The one direction may be parallel to the longitudinal direction of the side portion (26). Each hole (41) may be a long hole formed in the one direction.

[0085] However, the configuration of the cutting line (40) is not limited thereto, and any configuration that can be easily broken compared to the surrounding area may form the cutting line (40). For example, a part of the fixing member (30) may have a thinner thickness than the surrounding area, and that part may form the cutting line (40).

[0086] The cutting line (40) can be formed at a position corresponding to the gap (g) or boundary between the receiving portion (22) and the side portion (26).

[0087] In more detail, the side portion (26) can form a predetermined gap (g) with the outer circumference (222) of the receiving portion (22). In this case, the cutting line (40) can be formed at a position corresponding to the gap (g) between the receiving portion (22) and the side portion (26).

[0088] However, the side portion (26) may not form a predetermined gap with the receiving portion (22) and may come into contact with the outer circumference (222) of the receiving portion (22). In this case, the cutting line (40) may be formed at a position corresponding to the boundary between the receiving portion (22) and the side portion (26).

[0089] That is, the cutting line (40) can be formed at the connecting portion (33) of the previously described fixing member (30). Accordingly, when a certain level of external force or more is applied to the fixing member (30), the cutting line (40) can be smoothly broken. If the cutting line (40) is formed at the first adhesive portion (31) or the second adhesive portion (32) of the fixing member (30), the cutting line (40) may not be preferentially broken.

[0090] The cutting line (40) may be formed at the first connecting portion (33A) of the fixing member (30) described above. In this regard, when the side portion (26) is about to unfold due to the high pressure within the battery case (20), a relatively high tension is applied to the first connecting portion (33A) of the fixing member (30), and a relatively low tension is applied to the second connecting portion (33B). Therefore, by forming the cutting line (40) at the first connecting portion (33A), the cutting line (40) can be broken more smoothly. However, it goes without saying that the cutting line may be formed not only at the first connecting portion (33A) but also at the second connecting portion (33B).

[0091] Figure 4 is a plan view of a secondary battery according to another embodiment of the present invention.

[0092] Below, we will omit any overlapping information from what was previously explained and focus on explaining the differences.

[0093] The fixing member (30) of the secondary battery according to the present embodiment may be extended along the longitudinal direction of the side portion (26). For example, the fixing member (30) may be a single member formed to be elongated along the longitudinal direction of the side portion (26), as illustrated in FIG. 4. Therefore, it may be difficult for the fixing member (30) to be completely broken.

[0094] In order for the fixed member (30) to be broken more smoothly, a sub-cut line (50) formed long in a direction intersecting the cutting line (40) may be further formed on the fixed member (30). In more detail, the sub-cut line (50) may be formed in a direction perpendicular to the cutting line (40).

[0095] Sub-cut lines (50) can be formed at predetermined intervals in the extension direction of the cut line (40). That is, sub-cut lines (50) can be formed at predetermined intervals in the length direction of the extension portion (26).

[0096] The sub-cut line (50) can be formed by forming holes (51) in the fixing member (30) at predetermined intervals in one direction. The one direction can be parallel to the direction in which the fixing member (30) wraps around the side portion (26).

[0097] However, the configuration of the sub-cut line (50) is not limited thereto, and any configuration that can be easily broken compared to the surroundings can form the sub-cut line (50). For example, a part of the fixing member (30) may have a thinner thickness than the surroundings, and that part may form the sub-cut line (50).

[0098] A sub-cut line (50) may be formed at a connecting portion (33) of a fixing member (30), particularly at a first connecting portion (33A). Preferably, the sub-cut line (50) may extend from one edge of the fixing member (30) to the opposite edge.

[0099] Meanwhile, it goes without saying that a sub-cutting line (50) can also be formed in the fixing member (30) of the secondary battery (1) according to the embodiment described above.

[0100] Figure 5 is a flowchart of a secondary battery manufacturing method according to another embodiment of the present invention.

[0101] Hereinafter, a method for manufacturing a secondary battery (1) according to one embodiment or another embodiment described above will be described as another embodiment of the present invention.

[0102] A method for manufacturing a secondary battery according to another embodiment of the present invention may include a step (S10) of folding a side portion (26) of a battery case (20) containing an electrode assembly (10) at least once, a step (S20) of preparing a fixing member (30) having a cutting line (40) formed along a preset direction, and a step (S30) of attaching the fixing member (30) to the battery case (20) so that the side portion (26) is fixed in a folded state.

[0103] In the step (S10) of folding the side portion (26), a secondary battery (1) can be prepared in which the terrace portions (23) (26) of the battery case (20) are sealed while the electrode assembly (10) is accommodated in the receiving portion (22). Thereafter, the second terrace portion (26) of the battery case (20), i.e., the side portion (26), can be folded at least once toward the receiving portion (22). The side portion (26) can be single-side folded (SSF) or double-side folded (DSF).

[0104] In the step (S20) of preparing a fixing member (30), a cutting line (40) may be formed on the fixing member (30). In addition, a sub-cutting line (50) intersecting the cutting line (40) may be further formed on the fixing member (30). The cutting line (40) and the sub-cutting line (50) may be formed by forming holes (41) (51) in the fixing member (30) at predetermined intervals in one direction. However, the configuration of the cutting line (40) and the sub-cutting line (50) is not limited thereto, and the cutting line (40) and the sub-cutting line (50) may be formed if the configuration is such that fracture may occur more easily than the surrounding area.

[0105] In the step (S30) of attaching the fixing member (30), both ends of the fixing member (30) may be adhered to the receiving portion (22), more specifically, to the bottom surface (221) of the receiving portion (22). However, this is not limited thereto, and one end of the fixing member (30) may be adhered to the receiving portion (22), more specifically, to the bottom surface (221) of one receiving portion (22), and the other end of the fixing member (30) may be adhered to the side (26).

[0106] In the step (S30) of attaching the fixing member (30), the fixing member (30) may be attached so that the cutting line (40) is parallel to the longitudinal direction of the side portion (26). The fixing member (30) may be attached so that the cutting line (40) corresponds to the gap (g) or boundary between the receiving portion (22) and the side portion (26). That is, the fixing member (30) may be attached so that the cutting line (40) is located at the connecting portion (33) of the fixing member (30), particularly at the first connecting portion (33A).

[0107] Through these series of steps, a secondary battery (1) can be manufactured. Thereafter, when high-temperature gas is generated due to abnormal operation of the electrode assembly (10), the pressure inside the battery case (20) increases. At this time, an external force (tension) can be applied to the fixing member (30) during the process of unfolding the folded side portion (26). When a certain level or more of external force is applied to the fixing member (30), the portion along the cut line (40) can be preferentially broken. As a result, the side portion (26) can be unfolded, the sealing of the side portion (26) is released, and the gas and flame inside the battery case (20) can be quickly discharged.

[0108] The above description is merely an example of the technical idea of ​​the present invention, and those skilled in the art will appreciate that various modifications and variations can be made without departing from the essential characteristics of the present invention.

[0109] Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of ​​the present invention but to explain it, and the scope of the technical idea of ​​the present invention is not limited by these embodiments.

[0110] The scope of protection of the present invention should be interpreted by the claims below, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

[0111] [Explanation of symbols]

[0112] 10: Electrode assembly 12: Electrode lead

[0113] 14: Insulation 20: Battery case

[0114] 21: Folding section 22: Receiving section

[0115] 23: 1st terrace 26: 2nd terrace, side

[0116] 30: Fixed member 31: First adhesive part

[0117] 32: Second adhesive part 33: Connection part

[0118] 40: Cut line 41: Hole

[0119] 50: Sub-cut line 51: Hole

Claims

1. Electrode assembly; A battery case including a receiving portion for receiving the electrode assembly and a side portion located outside the receiving portion and folded at least once; and It includes a fixing member that is attached to the above battery case and fixes the side portion in a folded state, A secondary battery having a cut line formed on the above-mentioned fixing member so that the fixing member is easily broken when an external force is applied to the above-mentioned fixing member.

2. In paragraph 1, The above-mentioned cutting line is a secondary battery formed by forming holes in the fixing member at predetermined intervals in one direction.

3. In paragraph 1, The above-mentioned cutting line is formed in a long direction in the longitudinal direction of the side portion of the secondary battery.

4. In paragraph 1, A secondary battery having a sub-cut line formed long in a direction intersecting the cut line in the above-mentioned fixing member.

5. In paragraph 4, The above sub-cutting lines are formed at predetermined intervals in the extension direction of the above-mentioned cutting lines, which is a secondary battery.

6. In paragraph 1, The above-mentioned cutting line is formed at a position corresponding to the gap or boundary between the receiving portion and the side portion.

7. In paragraph 1, The above fixed member is, A first adhesive portion bonded to the above-mentioned receiving portion; A second adhesive portion attached to the side portion; and A secondary battery including a connecting portion connecting the first adhesive portion and the second adhesive portion.

8. In paragraph 7, The above cut line is a secondary battery formed at the above connecting portion.

9. In paragraph 7, The above connection part is, A first connecting portion located on the side where the side portion is folded and having the cut line formed thereon; and A secondary battery including a second connecting portion located opposite the first connecting portion with respect to the second adhesive portion.

10. A step of folding the side portion of the battery case containing the electrode assembly at least once; A step of preparing a fixed member having a cutting line formed along a preset direction; and A method for manufacturing a secondary battery, comprising a step of attaching the fixing member to the battery case so that the side portion is fixed in a folded state.

11. In paragraph 10, A method for manufacturing a secondary battery, wherein, in the step of attaching the above-mentioned fixing member, the fixing member is attached so that the cutting line is parallel to the longitudinal direction of the side portion.

12. In paragraph 10, A method for manufacturing a secondary battery, wherein, in the step of attaching the above-mentioned fixing member, the fixing member is attached so that the cut line corresponds to the gap or boundary between the receiving portion in which the electrode assembly is received and the side portion.

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