Secondary battery and method for manufacturing secondary battery

Abstract

A secondary battery according to the present invention comprises: an electrode assembly; and a battery case including an accommodation portion, which accommodates the electrode assembly together with an electrolyte, and a side portion, which extends from the accommodation portion. The side portion includes: a cut section formed adjacent to the end of the side portion to discharge gas from the inside of the accommodation portion; and a plurality of sealing sections arranged between the cut section and the accommodation portion to prevent the electrolyte from moving toward the cut section while gas is being discharged through the cut section. The plurality of sealing sections have gas discharge flow paths formed between the respective sealing sections to discharge the gas, and include inflow prevention sections which are located adjacent to inlets of the gas discharge flow paths and extend toward the accommodation portion to prevent the electrolyte from flowing into the gas discharge flow paths.

Description

Secondary battery and method for manufacturing secondary battery

[0001] [Cross-reference with related applications]

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0031381, filed March 5, 2024, the entire disclosure of which is incorporated herein by reference.

[0003] [Technical Field]

[0004] The present invention relates to a secondary battery and a method for manufacturing the secondary battery. More specifically, the invention relates to a secondary battery and a method for manufacturing the secondary battery that requires gas discharge.

[0005] With the technological development and increasing demand for electric vehicles, mobile devices, and other devices, the demand for secondary batteries as an energy source is increasing. Unlike primary batteries, secondary batteries can be recharged and reused after a single use. A secondary battery consists of a cathode and anode. When a metal in the cathode oxidizes, electricity is generated through the movement of electrons released from the metal.

[0006] To manufacture such a secondary battery, an electrode active material slurry is first applied to a positive electrode current collector and a negative electrode current collector to manufacture a positive electrode and a negative electrode, which are then laminated on both sides of a separator to form an electrode assembly. The electrode assembly is then housed in a battery case, filled with electrolyte, and sealed.

[0007] Secondary batteries are classified into pouch type and can type, depending on the material of the case that houses the electrode assembly. Pouch type secondary batteries are formed by housing the electrode assembly in a pouch made of a flexible polymer material. Can type secondary batteries are formed by housing the electrode assembly in a case made of a material such as metal or plastic.

[0008] The pouch, which is the battery case of a pouch-type secondary battery, is manufactured by forming a receiving portion by press-processing a flexible pouch film. Once the receiving portion is formed, an electrode assembly is accommodated in the electrode receiving space of the receiving portion, and the side portions extending from the receiving portion are fused to seal the pouch.

[0009] Before fusing the side portions, an activation process may be performed to test charge and / or discharge the secondary battery. During the activation process, the electrode assembly within the receiving portion may react with the electrolyte to generate gas. To discharge the gas formed during the activation process to the outside of the battery case, a portion of the side portion may be cut or punched to form a cut portion. However, in this case, it is necessary to prevent the electrolyte from escaping through the cut portion while the gas is discharged toward the cut portion. This is because if the electrolyte decreases, the capacity of the secondary battery may decrease.

[0010] The present invention has been devised to solve the above problems, and the object of the present invention is to provide a secondary battery configured to prevent discharge of electrolyte during a degassing process.

[0011] The technical problems to be achieved in this document are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present disclosure belongs from the description below.

[0012] A secondary battery according to one embodiment of the present invention includes a battery case including an electrode assembly and a receiving portion for receiving the electrode assembly together with an electrolyte, and a side portion extending from the receiving portion, wherein the side portion includes a cut portion formed adjacent to an end of the side portion for discharging gas within the receiving portion, and a plurality of sealing portions positioned between the cut portion and the receiving portion for preventing the electrolyte from moving to the cut portion while the gas is discharged to the cut portion, and wherein the plurality of sealing portions include an inflow prevention portion, wherein a gas discharge path is formed between each of the sealing portions for discharging the gas, and is positioned adjacent to an inlet of the gas discharge path, and extends toward the receiving portion for preventing the electrolyte from flowing into the gas discharge path.

[0013] Each of the plurality of sealing portions may include a sealing portion body that supports the inflow prevention portion and forms a concave guide space in a direction away from the receiving portion to guide the electrolyte together with the inflow prevention portion.

[0014] A plurality of sealing portions may be arranged in a direction parallel to the long side of the receiving portion.

[0015] The inflow prevention section may have a sloped surface that is inclined in a direction away from the receiving section with respect to the direction away from the gas discharge path.

[0016] Multiple sealing portions can be formed by fusing side portions.

[0017] The gas discharge path may be extended from the inlet to the outlet and may be diverted in at least one other direction.

[0018] The gas discharge path may include an inlet path extending in a first extension direction from an inlet near the receiving portion and a bent path extending in a second extension direction different from the first extension direction from the inlet path to prevent movement of the electrolyte.

[0019] The inlet euro can extend perpendicularly to the direction of arrangement of the plurality of sealing portions.

[0020] The gas discharge path may further include an outlet path extending in a third extension direction different from the second extension direction from an outlet located on the opposite side of the inlet.

[0021] The outlet euro can be connected to the bend euro.

[0022] The cross-sectional area of ​​the outlet duct may be smaller than the cross-sectional area of ​​the duct through which the gas formed in the cut is discharged.

[0023] The outlet may be adjacent to the incision.

[0024] The incisions may be provided in multiple numbers, and the gas discharge paths may be provided in multiple numbers to correspond to each of the multiple incisions.

[0025] The gas exhaust path may have a cross-sectional area that increases as it approaches the outlet, adjacent to the outlet.

[0026] The gas exhaust path may have a smaller cross-sectional area adjacent to the inlet as it moves away from the inlet.

[0027] A secondary battery according to one embodiment of the present invention includes a battery case including an electrode assembly and a receiving portion for receiving the electrode assembly together with an electrolyte, and a side portion extending from the receiving portion, wherein the side portion includes a cut portion formed adjacent to an end of the side portion for discharging gas within the receiving portion, and a plurality of sealing portions positioned between the cut portion and the receiving portion for preventing the electrolyte from moving to the cut portion while the gas is discharged through the cut portion, and a gas discharge path is formed between each of the plurality of sealing portions for discharging gas, and the gas discharge path extends from an inlet to an outlet while changing direction at least once.

[0028] The plurality of sealing portions may include an inlet prevention portion positioned adjacent to the inlet of the gas discharge passage and extending toward the receiving portion to prevent electrolyte from flowing into the gas discharge passage.

[0029] Each of the plurality of sealing portions may include a sealing portion body that supports the inflow prevention portion and forms a concave guide space in a direction away from the receiving portion to guide the electrolyte together with the inflow prevention portion.

[0030] A plurality of sealing portions may be arranged in a direction parallel to the long side of the receiving portion.

[0031] A method for manufacturing a secondary battery according to one embodiment of the present invention includes a step of sealing a lead sealing portion of a side portion of a battery case located on the outside of an electrode assembly, a step of forming a cut portion adjacent to an end of the side portion, a step of forming a plurality of sealing portions located between the cut portion and a receiving portion of the battery case so that a gas discharge path is formed therebetween, and a step of discharging gas generated by activating the electrode assembly through the gas discharge path to the cut portion, wherein the plurality of sealing portions are located adjacent to an inlet of the gas discharge path and include a step of forming an inflow prevention portion by fusing the side portion and protruding toward the receiving portion so as to prevent an electrolyte from flowing into the gas discharge path.

[0032] A secondary battery according to the present invention includes a plurality of sealing portions positioned between a cut portion and a receiving portion, each of which has a gas discharge path formed therebetween so that gas can be discharged, thereby preventing discharge of electrolyte during a degassing process.

[0033] The secondary battery according to the present invention can prevent discharge of the electrolyte by including a plurality of sealing portions including an inflow prevention portion positioned adjacent to an inlet of a gas discharge passage and extending toward a receiving portion to prevent the electrolyte from flowing into the gas discharge passage.

[0034] The secondary battery according to the present invention can prevent discharge of the electrolyte by forming a gas discharge path that extends and changes direction at least once from the inlet to the outlet.

[0035] The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the description below.

[0036] Figure 1 is a perspective view of a secondary battery according to a first embodiment of the present invention.

[0037] Figure 2 is an assembly diagram of the secondary battery illustrated in Figure 1.

[0038] Figure 3 is a plan view showing a portion of the battery case of the secondary battery illustrated in Figure 2 after being fused, as viewed from above.

[0039] Fig. 4 is a plan view showing a sealing portion formed in the battery case of the secondary battery illustrated in Fig. 3.

[0040] Figure 5 is an enlarged view showing V of Figure 4.

[0041] Figure 6 is an enlarged view showing an enlarged version of Ⅵ of Figure 4.

[0042] Figure 7 is a flowchart regarding a method for manufacturing a secondary battery disclosed in Figure 1.

[0043] Figure 8 is an enlarged view of a secondary battery according to a second embodiment of the present invention.

[0044] Figure 9 is an enlarged view of a secondary battery according to a third embodiment of the present invention.

[0045] Figure 10 is an enlarged view of a secondary battery according to the fourth embodiment of the present invention.

[0046] Figure 11 is an enlarged view of a secondary battery according to the fifth embodiment of the present invention.

[0047] Figure 12 is an enlarged view of a secondary battery according to the sixth embodiment of the present invention.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] It should be understood that the various embodiments and terms used in this document are not intended to limit the technical features described in this document to specific embodiments, but rather to include various modifications, equivalents, or substitutes of the embodiments.

[0052] In connection with the description of the drawings, similar reference numerals may be used for similar or related components.

[0053] The singular form of a noun corresponding to an item may include one or more of said items, unless the relevant context clearly indicates otherwise.

[0054] In this document, each of the phrases "A or B", "at least one of A and B", "at least one of A or B", "A, B, or C", "at least one of A, B, and C", and "at least one of A, B, or C" may include any one of the items listed together in that phrase, or all possible combinations thereof.

[0055] The term "and / or" includes any combination of a plurality of related described elements or any one of a plurality of related described elements.

[0056] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish one component from another and do not qualify the components in any other respect (e.g., importance or order).

[0057] When a component (e.g., a first component) is referred to as being "coupled" or "connected" to another component (e.g., a second component), with or without the terms "functionally" or "communicatively," it means that the component can be connected to the other component directly (e.g., wired), wirelessly, or through a third component.

[0058] The terms "include" or "have" are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in this document, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0059] When a component is said to be “connected,” “coupled,” “supported,” or “in contact with” another component, this includes not only cases where the components are directly connected, coupled, supported, or in contact, but also cases where the components are indirectly connected, coupled, supported, or in contact through a third component.

[0060] When we say that a component is "on" another component, this includes not only cases where the component is in contact with the other component, but also cases where there is another component between the two components.

[0061] Meanwhile, the terms “upper and lower directions,” “lower side,” and “front and rear directions” used in the following description are defined based on the drawings, and the shape and position of each component are not limited by these terms.

[0062] Hereinafter, embodiments according to the present invention will be described in detail with reference to the attached drawings.

[0063] Fig. 1 is a perspective view of a secondary battery (B) according to a first embodiment of the present invention. Fig. 2 is an assembly diagram of the secondary battery (B) illustrated in Fig. 1. Fig. 3 is a plan view illustrating a portion of a battery case (200) of the secondary battery (B) illustrated in Fig. 2 after being fused, as viewed from above.

[0064] Referring to FIGS. 1 to 3, a secondary battery (B) according to a first embodiment of the present invention will be described.

[0065] As illustrated in FIG. 1, a secondary battery (B) configured to generate electricity may be provided. In the following description, the term "secondary battery (B)" may refer to a secondary battery (B) that has been completed through a process, or may refer to a secondary battery (B) that is in the process of being processed. Therefore, the term "secondary battery (B)" in this context may be understood depending on the context.

[0066] As illustrated in FIG. 2, the secondary battery (B) may include an electrode assembly (100). The electrode assembly (100) may be formed by alternately stacking electrodes and separators. First, a slurry containing an electrode active material, a binder, and a plasticizer may be applied to a positive electrode current collector and a negative electrode current collector to manufacture electrodes such as a positive electrode and a negative electrode. Then, separators may be stacked between the electrodes to form an electrode assembly (100), and the electrode assembly (100) may be inserted into a battery case (200), filled with an electrolyte, and then sealed. At this time, the battery case (200) may be, for example, a pouch type. In the following description, a pouch or pouch-type battery case (200) may be regarded as an example of a battery case (200), and may refer to the battery case (200).

[0067] Specifically, the electrode assembly (100) may include two types of electrodes, a positive electrode and a negative electrode, and a separator interposed between the electrodes to mutually insulate the electrodes. This electrode assembly (100) may be provided in a stack type, a jelly roll type, a stack and folding type, etc., depending on how the positive electrode, the negative electrode, and the separator are stacked. The two types of electrodes, i.e., the positive electrode and the negative electrode, may each have a structure in which an active material slurry is applied to an electrode current collector in the form of a metal foil or metal mesh containing aluminum and copper, respectively. The slurry may typically be formed by stirring a granular active material, an auxiliary conductor, a binder, a plasticizer, etc. in a state in which a solvent is added. The solvent of the slurry may be removed in a subsequent process.

[0068] More specifically, the positive electrode may include a positive electrode material with a strong oxidizing ability that provides electrons. For example, the positive electrode material may include lithium ions, a transition metal, and oxygen. Nickel, cobalt, or manganese may be used as the transition metal. The negative electrode may include a negative electrode material with a strong reducing ability that accepts electrons. For example, the negative electrode material may include graphite. When the secondary battery (B) is charged and discharged, electrons may move according to the movement of lithium ions. In this case, lithium ions may move through an electrolyte located between the positive electrode and the negative electrode, and electrons may move through a conductor connecting the positive electrode and the negative electrode.

[0069] The electrode tabs (130) are connected to the positive and negative electrodes of the electrode assembly (100), respectively, and protrude outward from the electrode assembly (100) to serve as a path through which electrons can move between the inside and the outside of the electrode assembly (100). The plurality of electrode tabs (130) may protrude in different directions of the electrode assembly (100), as illustrated in FIG. 2, but are not limited thereto, and the plurality of electrode tabs (130) may protrude in parallel in the same direction or in various directions.

[0070] The electrode assembly (100) may include an electrode lead (110) that is connected to an electrode tab (130) and supplies electricity to the outside of the secondary battery (B). The electrode lead (110) may be connected to the electrode tab (130) by spot welding, etc.

[0071] The electrode assembly (100) may include an insulating portion (120) surrounding a portion of the electrode lead (110). The insulating portion (120) may be positioned to correspond to a position where the side portion (220) described below is fused. When the opposing side portions (220) are fused to each other, the insulating portion (120) may be positioned between the side portions (220) to adhere the electrode lead (110) to the pouch. In addition, the insulating portion (120) may prevent electricity generated from the electrode assembly (100) from flowing to the pouch through the electrode lead (110) and maintain the sealing of the pouch. Therefore, the insulating portion (120) may be made of a non-conductive material that does not conduct electricity well. For example, the insulating portion (120) may be an insulating tape that is easy to attach to the electrode lead (110) and has a relatively thin thickness. However, without limitation thereto, various materials may be used as long as the electrode lead (110) can be insulated.

[0072] The electrode tab (130) configured to have a positive electrode may be referred to as a positive electrode tab, the electrode tab (130) configured to have a negative electrode may be referred to as a negative electrode tab, the electrode lead (110) configured to have a positive electrode may be referred to as a positive electrode lead, and the electrode lead (110) configured to have a negative electrode may be referred to as a negative electrode lead. The electrode lead (110) may have one end connected to the electrode tab (130) and the other end protruding outward from the pouch. That is, the electrode lead (110) may include a positive lead having one end connected to the positive electrode tab and extending in the direction in which the positive electrode tab protrudes, and a negative lead having one end connected to the negative electrode tab and extending in the direction in which the negative electrode tab protrudes. Meanwhile, both the positive electrode lead and the negative electrode lead may have other ends protruding outward from the pouch. Accordingly, the positive electrode lead and the negative electrode lead may supply electricity generated inside the electrode assembly (100) to the outside. Additionally, the positive and negative tabs can each extend in different directions.

[0073] The positive and negative electrode leads may be made of different materials. The positive electrode lead may be made of the same aluminum material as the positive electrode collector, and the negative electrode lead may be made of the same copper material as the negative electrode collector or of nickel-coated copper. Furthermore, a portion of the electrode lead (110) protruding from the outside of the pouch may serve as a terminal and be electrically connected to an external terminal.

[0074] A pouch film forming a pouch, which is an example of a battery case (200), may include a plurality of layers. The pouch film may include a sealant layer and a barrier layer positioned outside the sealant layer. It may include a surface protection layer positioned outside the barrier layer. At this time, the sealant layer may have a polymer material such as polypropylene, the barrier layer may have a metal material such as aluminum, and the surface protection layer may have a polymer material such as nylon. At this time, the fusion described below may mean that the facing pouch films are joined as the facing sealant layers are melted.

[0075] The pouch can be manufactured from a highly flexible material to accommodate the electrode assembly (100) therein. By drawing and forming a flexible pouch film using a punch (not shown) or the like, a portion of the pouch film is stretched to form a receiving portion (210) having a pocket-shaped electrode receiving space (210S), thereby manufacturing the pouch. The pouch can accommodate and seal the electrode assembly (100) such that a portion of the electrode lead (110) is exposed.

[0076] When forming a receiving portion (210) on a pouch film, only one receiving portion (210) may be formed on one pouch film, but the present invention is not limited thereto, and two receiving portions (210) may be drawn and formed adjacent to each other on one pouch film. Then, two receiving portions (210) adjacent to each other may be formed. Each receiving portion (210) may have the same depth, but the present invention is not limited thereto, and the depths of each receiving portion (210) may be different from each other. After the electrode assembly (100) is accommodated in one receiving portion (210), the pouch may be folded around an axis so that another receiving portion (210) faces the receiving portion (210). Accordingly, another receiving portion (210) may accommodate the electrode assembly (100) from the upper side. Since two receiving portions (210) receive one electrode assembly (100), an electrode assembly (100) having a thicker thickness can be received than when there is only one receiving portion (210). In addition, since the pouch is folded, each side portion (220) is integrally connected to form a folding portion (223), so that the number of sides to be sealed can be reduced when performing a sealing process later. Accordingly, the process speed can be improved and the number of sealing processes can be reduced. For the convenience of explanation, the battery case (200) described below is described assuming that two receiving portions (210) are formed on one pouch film.

[0077] The side portion (220) may include a lead sealing portion (221) configured to be positioned to correspond to the electrode lead (110) and a degassing portion (222) connected to the lead sealing portion (221). The lead sealing portion (221) may be a portion formed adjacent to the electrode lead (110) side of the side portion (220). The lead sealing portion (221) may extend in the width direction of the electrode lead (110). The lead sealing portion (221) may be sealed by fusion. Thereafter, an electrolyte may be injected into the electrode receiving space (210S) through the degassing portion (222), which is not yet sealed, and the degassing portion (222) may be sealed by fusion. Thereafter, an activation process may be performed, and when the gas generated through the activation process moves into the inside of the degassing portion (222), a degassing process for removing the remaining gas may be performed. After sealing the degas portion (222) again, a trimming process may be performed to cut off unnecessary portions so that the degas portion (222) has a predetermined width. Thereafter, as illustrated in FIG. 1, the degas portion (222) may be folded to reduce the width, thereby forming a folding portion (223).

[0078] At this time, Fig. 3 illustrates that an electrode assembly (100) according to one embodiment of the present invention is accommodated in a battery case (200), and a lead sealing portion (221) is formed by fusing the ends of the battery case (200) located at the upper and lower sides based on Fig. 3. A secondary battery (B) as illustrated in Fig. 3 can undergo an activation process.

[0079] The subsequent process is described below with reference to FIGS. 4 to 6.

[0080] Fig. 4 is a plan view showing a sealing portion (230) formed in a battery case (200) of the secondary battery (B) shown in Fig. 3. Fig. 5 is an enlarged view showing an enlarged portion V of Fig. 4. Fig. 6 is an enlarged view showing an enlarged portion VI of Fig. 4.

[0081] Referring to FIGS. 4 to 6, a sealing portion (230) according to one embodiment of the present invention will be described.

[0082] As described above, the battery case (200) may include a receiving portion (210) that receives the electrode assembly (100) together with an electrolyte and / or a side portion (220) extending from the receiving portion (210).

[0083] At this time, the side part (220) may include a cut-out part (250) formed adjacent to the end of the side part (220) to discharge gas within the receiving part (210). While the secondary battery (B) is undergoing an activation process, gas may be generated by the reaction between the electrode assembly (100) and the electrolyte. The gas may need to be removed because it may deteriorate the electrical characteristics of the secondary battery (B). At this time, the battery case (200) may be covered on the left side by the folding part (223) based on FIG. 4 during the activation process, and the upper and lower sides may be sealed by the lid sealing part (221). The right side of the battery case (200) may also be sealed. In other words, unlike as illustrated in FIG. 4, the end of the degas portion (222) may be fused to prevent gas generated in the receiving portion (210) from being discharged through the end of the degas portion (222). The purpose of fusing the end of the degas portion (222) may be to prevent leakage of the electrolyte as described below. At this time, the above-described cut portion (250) may be formed to facilitate discharge of the gas. The cut portion (250) may be formed by cutting a part of the degas portion (222) by drawing a knife or the like in one direction as illustrated in the drawing, but the cut portion (250) may be formed to be a hole so that the gas is discharged through the cut portion (250) defined as the hole. Additionally, the arrow illustrated in FIG. 4 may indicate the direction of movement of the gas. The gas may escape toward the right side where the seal is not formed. In other words, the gas can be discharged from the inside of the receiving portion (210) to the outside of the secondary battery (B) through the degas portion (222).

[0084] Furthermore, the idea of ​​the present disclosure is not limited thereto, and the right end of the degas portion (222) may be opened without being sealed. However, for convenience of explanation, the battery case (200) described below is explained assuming that the end of the degas portion (222) is fused during the activation process and the degassing process.

[0085] However, while the gas generated by the activation process is moving, the electrolyte located within the receiving portion (210) may also move toward the cut portion (250) along with the movement of the gas. In the secondary battery (B), the amount of electrolyte accommodated in the receiving portion (210) corresponds to the electrical capacity, so it is necessary to prevent the electrolyte from leaking out. To this end, the secondary battery (B) may include a sealing portion (230) located between the cut portion (250) and the receiving portion (210) to prevent the electrolyte from moving to the cut portion (250) while the gas is discharged to the cut portion (250).

[0086] At this time, if the sealing portion (230) is connected to the lead sealing portions (221) located at the upper and lower sides, it may be difficult for the gas generated by the electrode assembly (100) to be discharged to the outside. In order to prevent the electrolyte from moving toward the cut portion (250) while the gas moves through the cut portion (250), a plurality of sealing portions (230) may be provided, and a gas discharge path (240) may be formed between the plurality of sealing portions (230) to discharge the gas. The gas discharge path (240) may have a cross-sectional area that allows the gas to pass through while making it difficult for the electrolyte to move.

[0087] As illustrated in Fig. 4, a plurality of sealing portions (230) may be arranged in a direction parallel to the long side of the receiving portion (210). If there are a plurality of gas discharge paths (240), the plurality of gas discharge paths (240) may also be arranged in a direction parallel to the long side of the receiving portion (210). Since the gas discharge paths (240) extend in a direction similar to the direction in which gas moves in the receiving portion (210), gas discharge may be facilitated.

[0088] A plurality of sealing portions (230) may be formed by fusing the side portions (220). As mentioned above, the pouch film may have a sealant layer positioned on the inside, and the sealant layer may melt when heat is applied. When the sealant layers positioned on the inside of the facing pouch films are heated and pressurized, they may be fused to each other, thereby forming a plurality of sealing portions (230). Accordingly, gas may be prevented from moving through the plurality of sealing portions (230). Of course, the plurality of sealing portions (230) may be formed by providing separate blocks rather than fusing the side portions (220). However, for the convenience of explanation, the present disclosure assumes and explains that the plurality of sealing portions (230) are formed by fusing the side portions (220).

[0089] For reference, the plurality of sealing portions (230) may not all have the same length, and may not be connected to the lead sealing portion (221) unlike that illustrated in FIG. 5. Accordingly, a gas discharge path (240) may be formed between the lead sealing portion (221) and the adjacent sealing portion (230). However, for convenience of explanation, it is assumed and explained that the sealing portion (230) adjacent to the lead sealing portion (221) is connected to the lead sealing portion (221).

[0090] However, since the electrolyte may still be a fluid, it may move to the cut portion (250) through the gas discharge passage (240). To prevent this, as illustrated in FIG. 6, the sealing portion (230) may include an inflow prevention portion (231) positioned adjacent to the inlet (241A) of the gas discharge passage (240) and extending toward the receiving portion (210) to prevent the electrolyte from flowing into the gas discharge passage (240). The inflow prevention portion (231) may function to prevent the movement of the electrolyte entering the gas discharge passage (240). In particular, if a part of the gas discharge passage (240) is blocked as illustrated in FIG. 8 or FIG. 9 as another embodiment, it may become difficult for the electrolyte to flow into the gas discharge passage (240) from a direction other than the front or rear of the gas discharge passage (240). Even when the inflow prevention part (231) is smoothly connected to the adjacent part as illustrated in FIG. 5, it may be difficult to dramatically prevent the electrolyte from flowing into the gas discharge path (240) compared to the embodiments illustrated in FIGS. 8 and 9, but it may nevertheless be difficult for the electrolyte to flow toward the gas discharge path (240). In particular, the extension of the inflow prevention part (231) toward the receiving part (210) may mean that it extends in the opposite direction to the movement direction of the electrolyte moving in the receiving part (210). Therefore, since the extension direction of the sealing part (230) is a direction that impedes the movement of the electrolyte, it may impede the movement of the electrolyte. Furthermore, the extension of the inflow prevention part (231) toward the receiving part (210) may mean that it extends toward the receiving part (210) more than the adjacent part of the inflow prevention part (231). The electrolyte facing the inflow prevention section (231) can be induced to move to a part that is not closer to the receiving section (210) than the inflow prevention section (231) located adjacent to the inflow prevention section (231) while in contact with the inflow prevention section (231).If the electrolyte moves away from the inflow prevention section (231) and the gas discharge path (240), a flow in that direction of movement is formed, and the possibility of the following electrolyte also flowing in a similar direction to the preceding electrolyte increases.

[0091] Furthermore, as illustrated in FIG. 6, each of the plurality of sealing portions (230) may include a sealing portion body (232) that supports an inflow prevention portion (231) and forms a concave guide space (232S) away from the receiving portion (210) to guide the electrolyte together with the inflow prevention portion (231). Accordingly, the electrolyte that meets the inflow prevention portion (231) may move to the guide space (232S). The guide space (232S) may include a smooth curved surface or a straight plane to facilitate movement of the electrolyte.

[0092] As illustrated in FIG. 5, the inflow prevention portion (231) may have an inclined surface (231A) that is inclined in a direction away from the receiving portion (210) with respect to the direction away from the gas discharge passage (240). Accordingly, the electrolyte that comes into contact with the inflow prevention portion (231) may smoothly move away from the gas discharge passage (240) along the inclined surface (231A). By providing the inclined surface (231A), the inflow prevention portion (231) may be formed longer along the extension direction of the sealing portion (230) than when the inclined surface (231A) is not provided. In particular, compared to the inflow prevention portion (231) illustrated in FIG. 8, which is illustrated as another embodiment, the inflow prevention portion (231) illustrated in FIG. 5 may be formed more smoothly and to come into contact with the electrolyte more. The ability to smoothly move the electrolyte may mean that turbulence is prevented from forming in the movement of the electrolyte or that a force that impedes the movement can be minimized. More contact with the electrolyte may mean that more electrolyte can be moved into the guide space (232S) of the sealing portion (230).

[0093] The inclined surface (231A) is depicted as a straight line in FIG. 5, but it may be implemented as a curved surface whose slope becomes steeper as it gets farther from the receiving portion (210), a curved surface whose slope becomes narrower as it gets farther from the receiving portion (210), or a curved surface having an inflection point and having various changes in curvature. However, for the convenience of explanation, in the present disclosure, it is assumed and explained that the inclined surface is a straight line as in FIG. 5.

[0094] Additionally, the inflow prevention portions (231) may be provided to be positioned at both ends of one sealing portion (230). Since a gas discharge passage (240) may be formed between both ends of one sealing portion (230) and an adjacent sealing portion (230), a pair of inflow prevention portions (231) may be provided at both ends of one sealing portion (230) to prevent electrolyte from flowing into the gas discharge passage (240). Furthermore, as illustrated in FIG. 5, the sealing portion (230) in contact with the lead sealing portion (221) forms one gas discharge passage (240) with the adjacent sealing portion (230), and therefore, in this case, the inflow prevention portion (231) may be formed at only one end.

[0095] The gas discharge path (240) may be extended from the inlet (241A) to the outlet (243A) by changing direction at least once. If the gas discharge path (240) is extended in only one direction, it may be easier for the electrolyte to move through the gas discharge path (240). However, if the extension direction is changed while the gas discharge path (240) is moved in the extension direction, friction may occur while the electrolyte is moved at the part where the extension direction is changed, or the gas may remain at that part, which may increase the pressure and prevent the electrolyte from flowing into the gas discharge path (240). Accordingly, it may become more difficult for the electrolyte to enter the gas discharge path (240).

[0096] More specifically, the gas discharge path (240) may include an inlet path (241) extending in a first extension direction from an inlet (241A) close to the receiving portion (210). At this time, the inlet path (241) may extend perpendicularly to the arrangement direction of the plurality of sealing portions (230). With reference to FIG. 5, the inlet path (241) may extend in parallel in the left-right direction. The extension direction of the inlet path (241) may be similar to the movement direction of the gas discharged from the receiving portion (210). Therefore, the generated gas may be easily introduced into the inlet path (241).

[0097] The gas discharge path (240) may include a bent path (242) extending in a second extension direction different from the first extension direction from the inlet path (241) to prevent the electrolyte from moving. The second extension direction may be directed toward the upper right as illustrated in FIG. 5. However, the present invention is not limited thereto, and the second extension direction may be perpendicular to the first extension direction or directed toward the upper right. Furthermore, the bent path (242) may be directly connected to the outlet (243A) of the gas discharge path (240) as illustrated in FIG. 10. In this case, the number of bends of the gas discharge path (240) may be one. However, for the convenience of explanation, the description of the first embodiment will be described below assuming that the bent path (242) is not connected to the outlet (243A).

[0098] The gas discharge path (240) may further include an outlet path (243) extending in a third extension direction different from the second extension direction from an outlet (243A) located on the opposite side of the inlet (241A). The third extension direction may be a direction parallel to the first extension direction, as illustrated in FIG. 5. This may be to ensure smooth movement of the gas to the cut portion (250). Furthermore, the third extension direction may be a direction different from the cutting direction of the cut portion (250). This is because, when the cutting direction of the cut portion (250) and the third direction are parallel, it may be difficult for the gas to escape through the gap of the cut portion (250).

[0099] At this time, the outlet flow path (243) may be connected to the bending flow path (242). Accordingly, the gas discharge flow path (240) may be bent twice. Of course, the number of bends may be greater than two, as in other embodiments illustrated in FIG. 11.

[0100] The cross-sectional area of ​​the outlet flow path (243) may be smaller than the cross-sectional area of ​​the flow path through which the gas formed in the cut portion (250) is discharged. In other words, the cross-sectional area of ​​the flow path formed in the cut portion (250) may be larger than the cross-sectional area of ​​the outlet flow path (243). This is because, when the cross-sectional area of ​​a flow path increases, the speed of the fluid flowing in the flow path increases, the pressure of the fluid decreases, and thus the following fluid can move better toward the flow path. At this time, the cross-sectional area of ​​the flow path of the cut portion (250) is defined as the cross-sectional area of ​​the hole when the cut portion (250) is a hole, and when formed by an incision as illustrated in FIG. 5, it may be the cross-sectional area of ​​the flow path formed such that the incised line forms a circumference of a semicircle. This may be because a pair of opposing lines that are incised can be spread apart to form half of the flow path, and ideally, the flow path can have a cross-sectional area of ​​a circular shape.

[0101] The outlet (243A) may be adjacent to the cutout (250). This is because the gas that has exited the outlet (243A) must move directly through the cutout (250) to minimize loss of fluid energy due to friction during the movement process.

[0102] A plurality of incisions (250) may be provided, and a plurality of gas discharge paths (240) may be provided to correspond to each of the plurality of incisions (250). Accordingly, gas moving through the plurality of gas discharge paths (240) may be moved to an adjacent incision (250) without having to move to another incision (250), thereby shortening the distance the gas moves. Accordingly, loss of fluid energy due to friction of the gas may be minimized.

[0103] The gas discharge path (240) may have a smaller cross-sectional area as the portion adjacent to the inlet (241A) moves away from the inlet (241A). Accordingly, gas drawn into the inlet (241A) may be drawn more easily into the gas discharge path (240).

[0104] Figure 7 is a flowchart regarding a method for manufacturing a secondary battery disclosed in Figure 1.

[0105] Referring to FIG. 7, a method for manufacturing a secondary battery according to the first embodiment of the present invention will be described.

[0106] In order to form a sealing portion (230) that plays the above role, a secondary battery (B) can be manufactured by the following method.

[0107] The method for manufacturing a secondary battery (B) may include a step (S100) of sealing a lead sealing portion (221) of a side portion (220) of a battery case (200) located on the outside of an electrode assembly (100). The method for manufacturing a secondary battery (B) may further include a step (S200) of forming a cut portion (250) adjacent to an end of the side portion (220). The method for manufacturing a secondary battery (B) may further include a step (S300) of forming a plurality of sealing portions (230) located between the cut portion (250) and the receiving portion (210) of the battery case (200) such that a gas discharge path (240) is formed therebetween. The method for manufacturing a secondary battery (B) may further include a step (S400) of discharging gas generated by activation of the electrode assembly (100) through the gas discharge path (240) to the cut portion (250). The method for manufacturing a secondary battery (B) may include a step (S500) of forming a plurality of sealing portions (230) adjacent to an inlet (241A) of a gas discharge passage (240) and forming an inflow prevention portion (231) by fusing a side portion (220) so as to protrude toward the receiving portion (210) to prevent the electrolyte from flowing into the gas discharge passage (240).

[0108] Below, embodiments different from the first embodiment are described. Commonalities with the first embodiment will be omitted as much as possible, and the other embodiments will be described focusing on differences. In other words, it should be clear that any details not described in the other embodiments can be supplemented by the first embodiment.

[0109] Figure 8 is an enlarged view of a secondary battery (B) according to a second embodiment of the present invention.

[0110] Referring to FIG. 8, a secondary battery (B) according to a second embodiment of the present invention is described.

[0111] The second embodiment differs from the first embodiment in that the shape of the inflow prevention part (231-1) is different.

[0112] In the second embodiment, the inflow prevention portion (231-1) can protrude toward the receiving portion (210).

[0113] Furthermore, the gas discharge path (240) may be formed such that the cross-sectional area adjacent to the outlet (243A) increases as it moves toward the outlet (243A). This facilitates the movement of gas to the cut portion (250). This concept may also be applied to other embodiments.

[0114] Figure 9 is an enlarged view of a secondary battery (B) according to a third embodiment of the present invention.

[0115] Referring to FIG. 9, a secondary battery (B) according to a third embodiment of the present invention is described.

[0116] The third embodiment differs from the first embodiment in that the shape of the inflow prevention part (231-2) is different.

[0117] In the second embodiment, the inflow prevention section (231-2) can cover at least a portion of the inlet (241A) of the gas discharge passage (240). Accordingly, the electrolyte can be prevented from entering the gas discharge passage (240).

[0118] Figure 10 is an enlarged view of a secondary battery (B) according to the fourth embodiment of the present invention.

[0119] Referring to FIG. 10, a secondary battery (B) according to a fourth embodiment of the present invention is described.

[0120] The fourth embodiment differs from the first embodiment in that the shape of the gas discharge path (240-3) is different.

[0121] In the fourth embodiment, the gas discharge path (240-3) can be bent once along the extension direction. Accordingly, the movement of gas can be made smoother.

[0122] Figure 11 is an enlarged view of a secondary battery (B) according to the fifth embodiment of the present invention.

[0123] Referring to FIG. 11, a secondary battery (B) according to a fifth embodiment of the present invention is described.

[0124] The fifth embodiment differs from the first embodiment in that the shape of the gas discharge path (240) is different.

[0125] The gas discharge path (240-4) in the fifth embodiment may have more than two bends. Accordingly, the introduction of electrolyte into the gas discharge path (240-4) may become more difficult.

[0126] Figure 12 is an enlarged view of a secondary battery (B) according to the sixth embodiment of the present invention.

[0127] Referring to FIG. 12, a secondary battery (B) according to a sixth embodiment of the present invention is described.

[0128] The sixth embodiment differs from the first embodiment in that the shape of the gas discharge path (240-5) is different.

[0129] The gas discharge path (240-5) in the sixth embodiment may be branched. If branched, the cross-sectional area of ​​the outlet (243A) may substantially increase. Furthermore, the branched gas discharge path (240-5) may cause turbulent gas flow at the branch point, making it more difficult for the electrolyte to flow into the gas discharge path (240-5).

[0130] Unless explicitly stated otherwise, the embodiments described above may be combined with other embodiments. Alternatively, combinations between embodiments may be considered possible, unless one embodiment is explicitly restricted from being combined with another embodiment. Combinations of one embodiment with another embodiment are deemed to be disclosed in this document.

[0131] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various embodiments are possible within the scope equivalent to the technical idea of ​​the present invention and the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0132] [Explanation of symbols]

[0133] B: Secondary battery

[0134] 100: Electrode assembly

[0135] 110: Electrode lead

[0136] 120: Insulation

[0137] 130: Electrode tab

[0138] 200: Battery case

[0139] 210: Reception area

[0140] 210S: Electrode receiving space

[0141] 220: Side section

[0142] 221: Lead sealing section

[0143] 222: Digas Department

[0144] 223: Folding section

[0145] 230: Sealing part

[0146] 231: Inflow prevention unit

[0147] 231A: Inclined surface

[0148] 232: Sealing body

[0149] 232S: Guide space

[0150] 240: Gas discharge euro

[0151] 241A: Inlet

[0152] 243A: Outlet

[0153] 241: Inlet Euro

[0154] 242: Folding Euro

[0155] 243: Outlet Euro

[0156] 250: Incision

Claims

1. Electrode assembly; and A battery case including a receiving portion that receives the electrode assembly together with an electrolyte and a side portion extending from the receiving portion, The above side part, A cut formed adjacent to the end of the side portion to discharge gas within the receiving portion; and A plurality of sealing portions positioned between the cut portion and the receiving portion to prevent the electrolyte from moving to the cut portion while the gas is discharged through the cut portion, The above plurality of sealing parts are: A gas discharge path is formed between each of them so that the above gas can be discharged, A secondary battery comprising an inflow prevention portion positioned adjacent to an inlet of the gas discharge path and extending toward the receiving portion to prevent the electrolyte from flowing into the gas discharge path.

2. In paragraph 1, A secondary battery including a sealing body, wherein each of the plurality of sealing portions supports the inflow prevention portion and forms a concave guide space in a direction away from the receiving portion to guide the electrolyte together with the inflow prevention portion.

3. In paragraph 1, A secondary battery in which the plurality of sealing portions are arranged in a direction parallel to the long side of the receiving portion.

4. In paragraph 1, A secondary battery in which the above inflow prevention section has an inclined surface inclined in a direction away from the receiving section with respect to a direction away from the gas discharge path.

5. In paragraph 1, A secondary battery in which the plurality of sealing portions are formed by fusing the side portions.

6. In paragraph 1, A secondary battery in which the above gas discharge path extends from the inlet to the outlet and changes direction at least once.

7. In paragraph 1, The above gas discharge path is, An inlet flow path extending in a first extension direction from an inlet near the receiving portion; and A secondary battery comprising a bending channel extending in a second extension direction different from the first extension direction from the inlet channel to prevent movement of the electrolyte.

8. In paragraph 7, A secondary battery in which the above inlet euro extends perpendicularly to the arrangement direction of the plurality of sealing portions.

9. In paragraph 7, A secondary battery wherein the gas discharge path further includes an outlet path extending in a third extension direction different from the second extension direction from an outlet located on the opposite side of the inlet.

10. In paragraph 9, The above outlet euro is a secondary battery connected to the above bending euro.

11. In paragraph 9, A secondary battery in which the cross-sectional area of ​​the outlet path is smaller than the cross-sectional area of ​​the path through which the gas is discharged formed in the cut portion.

12. In paragraph 9, The above outlet is a secondary battery adjacent to the above cut-out.

13. In paragraph 1, The above incisions are provided in multiples, A secondary battery in which the above gas discharge path is provided in multiple numbers to correspond to each of the above cut portions.

14. In paragraph 1, The above gas discharge path is a secondary battery in which the cross-sectional area of ​​the part adjacent to the outlet increases as it moves toward the outlet.

15. In paragraph 1, The above gas discharge path is a secondary battery in which the cross-sectional area of ​​the part adjacent to the inlet decreases as it gets farther away from the inlet.

16. Electrode assembly; and A battery case including a receiving portion that receives the electrode assembly together with an electrolyte and a side portion extending from the receiving portion, The above side part, A cut formed adjacent to the end of the side portion to discharge gas within the receiving portion; and A plurality of sealing portions positioned between the cut portion and the receiving portion to prevent the electrolyte from moving to the cut portion while the gas is discharged through the cut portion, The plurality of sealing parts are formed with a gas discharge path between each of them so that the gas can be discharged. A secondary battery in which the above gas discharge path extends from the inlet to the outlet and changes direction at least once.

17. In paragraph 16, A secondary battery comprising a plurality of sealing portions, wherein the plurality of sealing portions are positioned adjacent to the inlet of the gas discharge path and include an inflow prevention portion extending toward the receiving portion to prevent the electrolyte from flowing into the gas discharge path.

18. In paragraph 17, A secondary battery including a sealing body that supports the inflow prevention portion and forms a concave guide space in a direction away from the receiving portion to guide the electrolyte together with the inflow prevention portion.

19. In paragraph 16, A secondary battery in which the plurality of sealing portions are arranged in a direction parallel to the long side of the receiving portion.

20. A step of sealing the lead sealing portion of the side of the battery case located on the outside of the electrode assembly; A step of forming a cut portion adjacent to an end of the side portion; A step of forming a plurality of sealing portions positioned between the above-mentioned cutting portion and the receiving portion of the battery case, such that a gas discharge path is formed therebetween; and A step of discharging gas generated by activating the electrode assembly to the cut portion through the gas discharge path, A secondary battery manufacturing method comprising a step of forming an inflow prevention portion by fusing the side portion, wherein the plurality of sealing portions are positioned adjacent to the inlet of the gas discharge passage and extending toward the receiving portion to prevent electrolyte from flowing into the gas discharge passage.

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