Prismatic-type secondary battery and manufacturing method thereof

Abstract

This prismatic-type secondary battery, which is characterized by comprising: a pouched-type secondary battery in which an electrode assembly connected to an electrode lead is accommodated in a pouch; a prismatic-type can having one side open to accommodate the pouched-type secondary battery; and a cap assembly including a metal current collector and inserted into the open one side of the prismatic-type can, wherein the electrode lead is bent while connected to the metal current collector when the cap assembly is inserted, can improve the efficiency of an electrolyte injection process through a structure in which the pouched-type secondary battery is inserted into the prismatic-type can.

Description

Square secondary battery and manufacturing method thereof

[0001] The present invention relates to a square secondary battery and a manufacturing method thereof, which can improve the efficiency of an electrolyte injection process through a structure in which a pouch-type secondary battery is inserted into a square can.

[0002] In general, a secondary battery is a battery that converts external electrical energy into chemical energy, stores it, and then generates electricity when needed. Commonly used secondary batteries include lead-acid batteries, nickel-cadmium batteries (Ni-Cd), nickel-metal hydride batteries (NiMH), lithium-ion batteries (Li-ion), and lithium-ion polymer batteries (Li-ion polymer).

[0003] These secondary batteries are manufactured by applying an active material to the surface of an electrode current collector to form a positive electrode and a negative electrode, interposing a separator between them to form an electrode assembly, and then mounting the electrode assembly inside a cylindrical or square metal can or a pouch-shaped case made of aluminum laminate sheet. The electrode assembly is manufactured mainly by injecting or impregnating a liquid electrolyte or using a solid electrolyte.

[0004] Therefore, secondary batteries are charged and discharged by allowing ions of the electrolyte injected between the positive and negative electrodes, which are insulated by a separator, to move between the positive and negative electrodes.

[0005] The electrodes used in the positive and negative electrodes of these secondary batteries include an electrode body constituting the electrode and an electrode active material coated on the electrode body.

[0006] The above electrode body may be generally processed into a sheet, thin plate, or foil form using a metal with excellent conductivity, such as aluminum (Al) or copper (Cu).

[0007] An electrode film for forming an electrode assembly is manufactured in a form in which an active material is applied to a portion of the film and the electrode body is exposed in the remaining portion.

[0008] The exposed portion of the above electrode body is processed to function as an electrode terminal for connecting the positive and negative electrodes to the outside when forming an electrode assembly (positive electrode, negative electrode, and separator).

[0009] Secondary batteries can be classified into cylindrical, prismatic, and pouch types depending on their shape.

[0010] Here, the pouch-type secondary battery has the advantages of being able to accommodate the aforementioned electrode assembly in a flexible pouch, allowing for relatively free configuration, a relatively easy manufacturing process, and low manufacturing costs. In particular, the pouch-type secondary battery can inject electrolyte into one side of the pouch, thereby increasing the efficiency of the electrolyte injection process compared to other types of secondary batteries.

[0011] However, pouch-type secondary batteries have concerns about their stability compared to other types of secondary batteries, as the pouch does not have rigidity and there is no vent structure to prevent explosion or fire when the internal pressure increases abnormally due to an abnormal condition of the secondary battery.

[0012] Conversely, square secondary batteries offer stability advantages due to the rigidity of the square can housing the electrode assembly and the aforementioned vent structure. However, because the electrolyte is injected into the interior of the square can through a hole, the electrolyte injection process in square secondary batteries is less efficient, corresponding to a neck process. Consequently, square secondary batteries suffer from lower productivity compared to pouch-type secondary batteries.

[0013] Therefore, a means is required to improve the productivity of secondary batteries by increasing the efficiency of the electrolyte injection process, while also pursuing structural stability.

[0014] The present invention provides a square secondary battery and a manufacturing method thereof, and more specifically, the purpose of the present invention is to provide a square secondary battery and a manufacturing method thereof that can improve the efficiency of an electrolyte injection process through a structure in which a pouch-type secondary battery is inserted into a square can.

[0015] In addition, the purpose is to provide a square secondary battery and a manufacturing method thereof that can manufacture a square secondary battery while reducing investment costs by utilizing the production line of an existing pouch-type secondary battery.

[0016] In addition, the purpose is to provide a square secondary battery and a manufacturing method thereof that can reduce material costs by making the pouch out of inexpensive materials compared to existing pouch-type secondary batteries.

[0017] In addition, the purpose is to provide a square secondary battery and a manufacturing method thereof that can prevent explosion or fire when internal pressure abnormally increases through a vent portion of a cap assembly.

[0018] The problems to be solved by the present invention 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 invention belongs from the description below.

[0019] A pouch-type secondary battery having an electrode assembly connected to an electrode lead housed in a pouch; a square can having one side open to house the pouch-type secondary battery; and a metal current collector, the square secondary battery including a cap assembly inserted into the open side of the square can, wherein the electrode lead is bent in a state in which it is connected to the metal current collector when the cap assembly is inserted.

[0020] The electrode lead may have one end protruding outside the pouch, and one end of the electrode lead may be fused and connected to the metal current collector.

[0021] One end of the above electrode lead can be bent vertically.

[0022] The electrode assembly includes an electrode tab connected to the electrode lead, and the electrode tab and a portion of the pouch containing the electrode tab are bendable together with the electrode lead.

[0023] The above pouch may contain plastic.

[0024] The electrode assembly may include an electrode film interposed between the pouch and the electrode lead.

[0025] The above square can may include a metal material, and the cap assembly may include a cap plate coupled to an inner surface of an open side of the square can.

[0026] The above cap plate may include a vent formed on one surface.

[0027] The above vent part may include a vent hole formed in the cap plate; and a vent positioned in the vent hole.

[0028] The above cap plate includes a metal material and can be joined to the inner surface of one open side of the square can by welding.

[0029] The cap assembly may include an insulating plate coupled between the metal collector and the cap plate.

[0030] A method for manufacturing a square secondary battery is provided, comprising the steps of: injecting an electrolyte into a pouch accommodating an electrode assembly to which electrode leads are connected; sealing and processing the pouch to produce a pouch-type secondary battery; inserting the pouch-type secondary battery into a square can having one open side; connecting the electrode leads to a metal current collector of a cap assembly; and inserting the cap assembly into the open side of the square can while the electrode leads are connected to the metal current collector.

[0031] The electrode lead may have one end protruding outside the pouch, and one end of the electrode lead may be fused and connected to the metal current collector.

[0032] One end of the above electrode lead can be bent vertically.

[0033] The electrode assembly includes an electrode tab connected to the electrode lead, and the electrode tab and a portion of the pouch containing the electrode tab are bendable together with the electrode lead.

[0034] The square secondary battery and its manufacturing method according to the present invention can improve the efficiency of the electrolyte injection process through a structure in which a pouch-type secondary battery is inserted into a square can.

[0035] Additionally, since the existing pouch-type secondary battery production line can be utilized, square secondary batteries can be manufactured while reducing investment costs.

[0036] Additionally, since the pouch can be made of inexpensive materials compared to existing pouch-type secondary batteries, material costs can be reduced.

[0037] Additionally, the vent section of the cap assembly can prevent explosion or fire when the internal pressure abnormally increases due to an abnormal condition.

[0038] 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 invention belongs from the description below.

[0039] FIG. 1 is a drawing illustrating a pouch-type secondary battery according to embodiments.

[0040] FIG. 2 and FIG. 3 are drawings illustrating a square secondary battery into which a pouch-type secondary battery is inserted according to embodiments.

[0041] FIG. 4 is a drawing illustrating a cap assembly in a square secondary battery according to embodiments.

[0042] Figure 5 is an exploded view of a cap assembly in a square secondary battery according to embodiments.

[0043] FIG. 6 is a drawing for explaining a method for manufacturing a square secondary battery according to embodiments.

[0044] Figure 7 is a drawing illustrating a square secondary battery according to embodiments.

[0045] Figures 8 to 12 are drawings illustrating a process for manufacturing a square secondary battery according to embodiments.

[0046] Fig. 13 is a drawing for explaining a method for manufacturing a square secondary battery according to embodiments.

[0047] FIG. 14 is a drawing illustrating a pouch-type secondary battery according to embodiments.

[0048] FIG. 15 is a drawing illustrating a cap assembly in a pouch-type secondary battery according to embodiments.

[0049] Fig. 16 is an exploded view of a cap assembly in a pouch-type secondary battery according to embodiments.

[0050] Figures 17 to 20 are drawings illustrating a process for manufacturing a pouch-type secondary battery according to embodiments.

[0051] FIG. 21 is a drawing illustrating a battery pack having a pouch-type secondary battery according to embodiments.

[0052] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Regardless of the drawing numbers, identical or similar components will be given the same reference numbers and redundant descriptions thereof will be omitted. The suffixes "module" and "part" used for components in the following description are assigned or used interchangeably only for the convenience of writing the specification, and do not in themselves have distinct meanings or roles. In addition, when describing the embodiments disclosed in this specification, if it is determined that a specific description of a related known technology may obscure the gist of the embodiments disclosed in this specification, a detailed description thereof will be omitted. In addition, the attached drawings are only intended to facilitate easy understanding of the embodiments disclosed in this specification, and the technical ideas disclosed in this specification are not limited by the attached drawings, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and technical scope of the present invention.

[0053] Terms that include ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by these terms. These terms are used solely to distinguish one component from another.

[0054] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0055] Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0056] In this application, terms such as “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, but should be understood not to exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0057] FIG. 1 is a drawing illustrating a pouch-type secondary battery (110) according to embodiments. FIG. 2 and FIG. 3 are drawings illustrating a square secondary battery (100) into which a pouch-type secondary battery (110) according to embodiments is inserted. FIG. 4 is a drawing illustrating a cap assembly (150) in a square secondary battery (100) according to embodiments. FIG. 5 is an exploded view of a cap assembly (150) in a square secondary battery (100) according to embodiments. And FIG. 6 is a drawing for explaining a method for manufacturing a square secondary battery (100) according to embodiments.

[0058] Referring to FIG. 1, a pouch-type secondary battery (110) can be manufactured through a process of forming an electrode assembly (120) by interposing a separator between electrodes as described above, then accommodating the electrode assembly (120) in a pouch (111) and injecting an electrolyte into the interior of the pouch (111).

[0059] And the electrode assembly (120) includes an electrode tab (121) connected to an electrode (122), and an electrode lead (130) can be connected to the electrode tab (121). The pouch (111) can accommodate the electrode assembly (120) and a part of the electrode lead (130). That is, one end of the electrode lead (130) protrudes outside the pouch (111). In addition, the electrode assembly (120) can include an electrode film (123) interposed between the pouch (111) and the electrode lead (130).

[0060] As described above, the pouch-type secondary battery (110) has the advantages of being able to have a relatively free shape by housing the electrode assembly (120) in a flexible pouch (111), having a relatively easy manufacturing process, and having a low manufacturing cost. In particular, the pouch-type secondary battery (110) can inject an electrolyte into one side of the pouch (111), and thus has a higher efficiency in the electrolyte injection process compared to other types of secondary batteries.

[0061] However, the pouch-type secondary battery (110) has a pouch (111) that does not have rigidity and does not have a vent structure to prevent explosion or fire when the internal pressure abnormally increases due to an abnormal condition of the secondary battery, so there are concerns about its stability compared to other types of secondary batteries.

[0062] Referring to FIG. 2 together, a square secondary battery (100) according to one embodiment of the present invention may include the above-described pouch-type secondary battery (110), a square can (140) having one side open to accommodate the pouch-type secondary battery (110), and a cap assembly (150) inserted into the open side of the square can (140). Here, the cap assembly (150) may include a metal current collector (151). In addition, the electrode lead (130) may be bent while being connected to the metal current collector (151) when the cap assembly (150) is inserted.

[0063] That is, the square secondary battery (100) according to one embodiment of the present invention has a structure in which a pouch-type secondary battery (110) is inserted into a square can (140) having rigidity, and thus can solve the stability problem, which is a shortcoming of the pouch-type secondary battery (110) described above.

[0064] Furthermore, since the square type of the existing secondary battery injects the electrolyte into the interior through a hole, the efficiency of the electrolyte injection process is low, corresponding to a neck process, and there is a disadvantage in that the productivity is low compared to the pouch type secondary battery (110).

[0065] Therefore, the square secondary battery (100) according to one embodiment of the present invention can solve the above-described problem and improve the productivity of the square secondary battery (100) of the present invention through a structure in which a pouch-type secondary battery (110) having a high efficiency of the electrolyte injection process is inserted into a square can (140).

[0066] In addition, since the square secondary battery (100) according to one embodiment of the present invention can utilize the production line of an existing pouch-type secondary battery (110), there is an effect of being able to manufacture the square secondary battery (100) while reducing investment costs.

[0067] As illustrated in Fig. 2, one end of the electrode lead (130) protruding outside the pouch (111) can be fused and connected to the metal current collector (151). At this time, one end of the electrode lead (130) can be bent vertically.

[0068] This is to manufacture a square secondary battery (100) according to one embodiment of the present invention, by fusing and connecting a metal current collector (151) of a cap assembly (150) to one end of an electrode lead (130) as shown in FIG. 1, and then bending the electrode lead (130) so that the electrode lead (130) is bent vertically.

[0069] And, by inserting a pouch-type secondary battery (110) and a cap assembly (150) into an open side of a square can (140), a square secondary battery (100) according to an embodiment of the present invention can be manufactured as shown in FIG. 2.

[0070] In addition, the square secondary battery (100) according to one embodiment of the present invention can be manufactured by reducing the length of the square can (140) by utilizing the advantage of a flexible pouch-type secondary battery (110). In this case, as illustrated in FIGS. 1 and 3, the electrode tab (121) of the pouch-type secondary battery (110) and a portion of the pouch (111) that accommodates the electrode tab (121) can be bent together with the electrode lead (130).

[0071] And through this, the length (L2) of the square can (140) illustrated in FIG. 3 can be reduced compared to the length (L1) of the square can (140) illustrated in FIG. 2, so when manufacturing a battery pack by arranging a plurality of square secondary batteries (100) of the present invention, there is a structural advantage in miniaturizing the battery pack or increasing the capacity of the battery pack.

[0072] In this case, as illustrated in FIGS. 2 and 3, the square secondary battery (100) according to one embodiment of the present invention can form the electrode lead (130) of the pouch-type secondary battery (110) to have a different length when processing the electrode lead (130), and through this, even if the length of the square can (140) is reduced, the electrode lead (130) and the metal current collector (151) can be stably connected.

[0073] Additionally, in the square secondary battery (100) according to one embodiment of the present invention, the square can (140) may include a metal material to ensure rigidity. In addition, the cap assembly (150) may include a cap plate (152) coupled to the inner surface of one open side of the square can (140).

[0074] Here, the cap plate (152) may include a metal material, and the cap plate (152) may be welded to a square can (140) made of a metal material and the cap plate (152) made of a metal material to join the cap plate (152) to the inner surface of one open side of the square can (140). Through this, the open side of the square can (140) may be sealed.

[0075] In addition, in the square secondary battery (100) according to one embodiment of the present invention, the pouch (111) may include plastic. Since a typical pouch functions to protect the electrode assembly (120) and forms the exterior, it is configured in a form in which a metal thin film is interposed to secure heat dissipation and rigidity.

[0076] However, since the square secondary battery (100) according to one embodiment of the present invention is inserted into a square can (140) having rigidity as a pouch-type secondary battery (110), the pouch (111) does not constitute the exterior. Accordingly, in the square secondary battery (100) according to one embodiment of the present invention, the pouch (111) can be manufactured from an inexpensive plastic from which the aforementioned metal film has been removed, thereby enabling a reduction in material costs.

[0077] Referring to FIGS. 4 and 5 together, in a square secondary battery (100) according to one embodiment of the present invention, the cap plate (152) of the cap assembly (150) may include a vent portion (153) formed on one surface. As described above, the pouch (111) secondary battery (110) had a disadvantage in terms of stability because it did not have a vent structure. Therefore, the square secondary battery (100) of the present invention can secure stability through the vent portion (153) while utilizing the advantages of the pouch (111) secondary battery (110).

[0078] Here, the vent part (153) may include a vent hole (1531) formed in the cap plate (152) and a vent (1532) located in the vent hole (1531). In an abnormal state, such as when the internal pressure of the square secondary battery (100) increases due to gas generation through the vent part (153), the vent (1532) may burst or fracture, thereby releasing the gas inside the square can (140) to the outside, thereby preventing an explosion or fire.

[0079] In addition, in the square secondary battery (100) according to one embodiment of the present invention, the cap assembly (150) may include an insulating plate (154) coupled between the metal current collector (151) and the cap plate (152). As described above, since the cap plate (152) includes a metal material in order to be welded to the square can (140), the insulating plate (154) may be positioned between the metal current collector (151) and the cap plate (152).

[0080] Furthermore, for the role of the vent portion (153) formed in the cap plate (152) described above, a hole may be formed in the insulating plate (154) at a position corresponding to the vent portion (153) as shown in FIG. 5.

[0081] Additionally, in a square secondary battery (100) according to one embodiment of the present invention, the cap assembly (150) may include a connection terminal (156) that is electrically connected to the outside. In addition, an insulating bracket (155) to which the connection terminal (156) is coupled may be coupled to the cap plate (152).

[0082] In addition, the cap assembly (150) may include a rivet terminal (157) for electrically connecting a metal current collector (151) connected to an electrode lead (130) to a connection terminal (156). In addition, a gasket (158) coupled to and interposed with the rivet terminal (157) may be included between the metal current collector (151) and the cap plate (152). Furthermore, the cap assembly (150) may include a seal ball (159) and a cover (1591) arranged at a position corresponding to an injection port for injecting an electrolyte.

[0083] Here, in the case of the square secondary battery (100) according to one embodiment of the present invention, since the electrolyte is injected into the pouch-type secondary battery (110), there is an advantage in that a separate electrolyte injection port can be omitted. Accordingly, the seal ball (159) and cover (1591) described above can be omitted.

[0084] FIG. 6 is a drawing for explaining a method for manufacturing a square secondary battery (100) according to one embodiment of the present invention. Hereinafter, the above-described method will be comprehensively explained with reference to FIGS. 1 to 5.

[0085] First, an electrolyte can be injected into a pouch (111) that accommodates an electrode assembly (120) to which an electrode lead (130) is connected (S110). Then, the pouch (111) can be sealed and processed to produce a pouch-type secondary battery (110) (S120). Thereafter, the pouch-type secondary battery (110) can be inserted into a square can (140) with one side open (S130), and the electrode lead (130) can be connected to a metal current collector (151) of a cap assembly (150) (S140).

[0086] In addition, the method for manufacturing the square secondary battery (100) of the present invention may include connecting the electrode lead (130) to the metal current collector (151) of the cap assembly (150) (S140), and then inserting the pouch-type secondary battery (110) into a square can (140) with one side open (S130).

[0087] And, with the electrode lead (130) connected to the metal current collector (151), the cap assembly (150) can be inserted into the open side of the square can (140) (S150). Thereafter, the cap plate (152) of the cap assembly (150) and the square can (140) can be welded to seal the open side of the square can (140).

[0088] Accordingly, the electrode lead (130) can be bent as described above, and a square secondary battery (100) of the present invention having a structure in which a pouch-type secondary battery (110) is inserted into a square can (140) can be manufactured.

[0089] In summary, the square secondary battery (100) and the manufacturing method thereof according to the present invention can improve the efficiency of the electrolyte injection process through the structure in which the pouch-type secondary battery (110) is inserted into the square can (140). In addition, since the production line of the existing pouch-type secondary battery (110) can be utilized, the square secondary battery (100) can be manufactured while reducing investment costs. In addition, since the pouch (111) can be composed of inexpensive materials compared to the existing pouch-type secondary battery (110), material costs can be reduced. In addition, the vent part (153) of the cap assembly (150) can prevent explosion or fire when the internal pressure abnormally increases in an abnormal state.

[0090] Fig. 7 is a drawing illustrating a square secondary battery (200) according to embodiments. Figs. 8 to 12 are drawings illustrating a process for manufacturing a square secondary battery (200) according to embodiments. And Fig. 13 is a drawing for explaining a method for manufacturing a square secondary battery (200) according to embodiments.

[0091] As illustrated in FIG. 7, a square secondary battery (200) according to one embodiment of the present invention may include an electrode assembly (210), a pouch (220), a square can (230), and a cap assembly (240). The electrode assembly (210) may include an electrode tab (211), and the pouch (220) may accommodate the electrode assembly (210). In addition, the pouch (220) may include a joint (221) that is formed to be open at a position corresponding to the electrode tab (211).

[0092] In addition, the square can (230) can accommodate the pouch (220) by having one side open. And the cap assembly (240) includes a metal current collector (241) and can be inserted into the open side of the square can (230). In particular, in the square secondary battery (200) according to one embodiment of the present invention, the pouch (220) can have the joint (221) joined to the cap assembly (240) while the electrode tab (211) is connected to the metal current collector (241).

[0093] Therefore, the square secondary battery (200) according to one embodiment of the present invention can solve the stability problem, which is a shortcoming of the pouch (220) type secondary battery (100) described above, through a structure in which the electrode assembly (210) is double-sealed with a pouch (220) and a square can (230) having rigidity.

[0094] And, unlike the square secondary battery (100) having a structure in which the pouch-type secondary battery (110) described above through FIGS. 1 to 6 is inserted, this can be implemented through a structure in which the electrode lead (130) is omitted from the pouch-type secondary battery (110) and the joint (221) of the pouch (220) is joined to the cap assembly (240).

[0095] In addition, the square can (230) and cap assembly (240) illustrated in FIG. 7 can correspond to the configuration of the square can (140) and cap assembly (150) described above with reference to FIGS. 1 to 6. Accordingly, the square secondary battery (200) according to one embodiment of the present invention can produce square secondary batteries (200) having various structures while utilizing the production line of the existing pouch-type secondary battery (110), thereby having the effect of reducing investment costs.

[0096] Additionally, the square secondary battery (200) according to one embodiment of the present invention may include a fire extinguishing agent (250) interposed between a pouch (220) and a square can (230). The fire extinguishing agent (250) may be, for example, coolant, and thereby ensure stability by more easily responding to fire or explosion. In addition, this can be implemented through the structure of the square secondary battery (200) of the present invention, which double-seals the electrode assembly (210) with a pouch (220) and a square can (230) having rigidity, as described above.

[0097] FIG. 8 is a drawing illustrating a shape in which one end of an electrode tab (211) is fused and connected to a metal current collector (241) in a square secondary battery (200) according to one embodiment of the present invention. As illustrated in FIG. 9, one end of the electrode tab (211) can be bent. At this time, one end of the electrode tab (211) can be bent vertically.

[0098] Thereafter, as illustrated in FIG. 10, the joint (221) of the pouch (220) can be joined to the cap assembly (240) to seal the electrode assembly (210) with the pouch (220) and the cap assembly (240). Then, as illustrated in FIGS. 11 and 12, an electrolyte can be injected into one side of the pouch (220), and the pouch (220) can be sealed and processed. Thereafter, as illustrated in FIG. 7, the square secondary battery (200) according to one embodiment of the present invention can be produced by inserting it into a square can (230).

[0099] Here, in the square secondary battery (200) according to one embodiment of the present invention, the square can (230) may include a metal material to ensure rigidity. In addition, the cap assembly (240) may include a cap plate (242) coupled to the inner surface of one open side of the square can (230).

[0100] Here, the cap plate (242) may include a metal material, and the metal material square can (230) and the metal material cap plate (242) may be welded to join the cap plate (242) to the inner surface of one open side of the square can (230). Through this, the open side of the square can (230) may be sealed.

[0101] In addition, in the square secondary battery (200) according to one embodiment of the present invention, the cap assembly (240) may include an insulating plate (244) coupled between the metal current collector (241) and the cap plate (242). As described above, since the cap plate (242) includes a metal material in order to be welded to the square can (230), the insulating plate (244) may be positioned between the metal current collector (241) and the cap plate (242).

[0102] Here, the joint (221) of the pouch (220) can be fused and joined to the outer surface of the insulating plate (244). That is, the joint (221) of the pouch (220) is fused and joined to the outer surface of the insulating plate (244), and the cap plate (242) is welded and joined to the inner surface of the open side of the square can (230), so that the square secondary battery (200) according to one embodiment of the present invention can implement the above-described double sealing structure.

[0103] As described above, in the square secondary battery (200) according to one embodiment of the present invention, the cap assembly (240) may correspond to the configuration of the cap assembly (150) illustrated in FIGS. 4 and 5. That is, in the square secondary battery (200) according to one embodiment of the present invention, the cap plate (242) of the cap assembly (240) may include a vent portion (153) formed on one surface.

[0104] As described above, the pouch (220)-type secondary battery (110) had a disadvantage in terms of stability due to the lack of a vent structure. Therefore, the square secondary battery (200) of the present invention can secure stability through the vent portion (153) while utilizing the advantages of the pouch-type secondary battery (110).

[0105] Here, the vent part (153) may include a vent hole (1531) formed in the cap plate (242) and a vent (1532) located in the vent hole (1531). In an abnormal state, such as when the internal pressure of the square secondary battery (200) increases due to gas generation through the vent part (153), the vent (1532) may burst or fracture, thereby releasing the gas inside the square can (230) to the outside, thereby preventing an explosion or fire.

[0106] Additionally, in a square secondary battery (200) according to one embodiment of the present invention, the cap assembly (240) may include a connection terminal (243) that is electrically connected to the outside. And, an insulating bracket to which the connection terminal (243) is coupled may be coupled to the cap plate (242). In addition, the cap assembly (240) may include a rivet terminal (246) for electrically connecting a metal current collector (241) connected to an electrode lead to the connection terminal (243).

[0107] Here, in the case of a square secondary battery (200) according to one embodiment of the present invention, since the electrolyte is injected into the pouch (220), there is an advantage in that a separate injection port for injecting the electrolyte can be omitted.

[0108] FIG. 13 is a drawing for explaining a method for manufacturing a square secondary battery (200) according to one embodiment of the present invention. Hereinafter, the above-described method will be comprehensively explained with reference to FIGS. 7 to 12.

[0109] First, the electrode tab (211) of the electrode assembly (210) contained in the pouch (220) can be connected to the metal current collector (241) of the cap assembly (240) (S210). Then, the electrode tab (211) can be bent while connected to the metal current collector (241) (S220). Thereafter, the opened joint (221) of the pouch (220) can be connected to the cap assembly (240) (S230).

[0110] And as shown in FIGS. 11 and 12, an electrolyte may be injected into one side of a pouch (220), and the pouch (220) may be sealed and processed (S240). Thereafter, the pouch (220) and the cap assembly (240) may be inserted into a square can (230) with one side open (S250). Then, the cap plate (242) of the cap assembly (240) and the square can (230) may be welded to seal the open side of the square can (230).

[0111] Accordingly, it is possible to produce a square secondary battery (200) of the present invention having a structure in which an electrode assembly (210) is double-sealed with a pouch (220) and a square can (230) having rigidity.

[0112] Additionally, the method for manufacturing a square secondary battery (200) according to one embodiment of the present invention can inject a fire extinguishing agent (250) between a pouch (220) and a square can (230) through the above-described double sealing structure (S260), thereby ensuring stability by more easily responding to fire or explosion.

[0113] In summary, the square secondary battery (200) and the manufacturing method thereof according to the present invention can improve the efficiency of the electrolyte injection process through a sealing structure in which a pouch (220) accommodating an electrode assembly (210) is inserted into a square can (230) and a joint (221) of the pouch (220) is joined to a cap assembly (240). In addition, the electrode assembly (210) is double-sealed with the pouch (220) and a rigid square can (230), and a extinguishing agent (250) is interposed between the pouch (220) and the rigid can, thereby ensuring stability. In addition, since the production line of an existing pouch-type secondary battery can be utilized, the square secondary battery (200) can be manufactured while reducing investment costs.

[0114] FIG. 14 is a drawing illustrating a pouch-type secondary battery (300) according to embodiments. FIG. 15 is a drawing illustrating a cap assembly (330) in a pouch-type secondary battery (300) according to embodiments. FIG. 16 is an exploded view of a cap assembly (330) in a pouch-type secondary battery (300) according to embodiments. FIGS. 17 to 20 are drawings illustrating a process for manufacturing a pouch-type secondary battery (300) according to embodiments. And FIG. 21 is a drawing illustrating a battery pack (400) including a pouch-type secondary battery (300) according to embodiments.

[0115] As illustrated in FIG. 14, a pouch-type secondary battery (300) according to one embodiment of the present invention may include an electrode assembly (310), a pouch (320), and a cap assembly (330). The electrode assembly (310) may include an electrode tab (311), and the pouch (320) may accommodate the electrode assembly (310). In addition, the pouch (320) may include a joint (321) that is formed to be open at a position corresponding to the electrode tab (311).

[0116] The cap assembly (330) may include a cap plate (332) to which a metal current collector (331) and a rapid current collector are coupled. In particular, in a pouch-type secondary battery (300) according to one embodiment of the present invention, the pouch (320) may have a joint (321) connected to the cap plate (332) while the electrode tab (311) is connected to the metal current collector (331).

[0117] And this can be implemented through a structure in which the electrode lead (130) is omitted from the pouch-type secondary battery (110) described above through FIG. 1, and the joint (321) of the pouch (320) is joined to the cap plate (332) of the cap assembly (330).

[0118] In addition, the pouch-type secondary battery (300) according to one embodiment of the present invention can improve energy density by reducing the so-called dead zone connecting the electrode tab (121) to the lead (130) by omitting the electrode lead (130) from the pouch-type secondary battery (1100) described above through FIG. 1.

[0119] Referring to FIGS. 15 and 16, in a pouch-type secondary battery (300) according to one embodiment of the present invention, the cap plate (332) of the cap assembly (330) may include a vent portion (3321) formed by being introduced on one side.

[0120] As described above through Fig. 1, the pouch-type secondary battery (110) has a disadvantage in that it has no vent structure to prevent explosion or fire when the internal pressure abnormally increases in an abnormal state, and thus has concerns about its stability compared to other types of secondary batteries.

[0121] Accordingly, a pouch-type secondary battery (300) according to one embodiment of the present invention may include a vent portion (3321), thereby improving stability. Here, since the vent portion (3321) is formed by being introduced into one surface of the cap plate (332), it may be formed with a thin thickness compared to the thickness of the cap plate (332).

[0122] And in an abnormal state, such as when the internal pressure of the pouch-type secondary battery (300) increases due to gas generation through the vent part (3321), the vent part (3321) can be ruptured or broken, releasing the internal gas to the outside to prevent an explosion or fire.

[0123] In addition, in the pouch-type secondary battery (300) according to one embodiment of the present invention, the cap plate (332) of the cap assembly (330) may include a fixing rib (3322) that is formed to protrude from one surface. In addition, the cap assembly (330) may include a connection terminal (333) that is electrically connected to the outside. In this case, the connection terminal (333) may be coupled through the fixing rib (3322).

[0124] In particular, compared to the cap assembly (150) described above in FIGS. 4 and 5, the cap plate (332) of the cap assembly (330) in the pouch-type secondary battery (300) according to one embodiment of the present invention can be formed integrally with the vent portion (3321) and the fixing rib (3322) through injection molding.

[0125] This is because, unlike the square secondary batteries (100, 200) described above with reference to FIGS. 1 to 13, the cap assembly (330) does not need to be joined to the square can (140, 230) by welding or other methods. That is, since it only needs to be joined to the joint portion (321) of the pouch (320), the cap plate (332) can be formed as an integral part of the vent portion (3321) and the fixing rib (3322) by injection molding using a plastic resin.

[0126] Furthermore, in a pouch-type secondary battery (300) according to one embodiment of the present invention, the cap assembly (330) may include a rivet terminal (334) that electrically connects the metal current collector (331) and the connection terminal (333). In addition, the cap assembly (330) may include a gasket (335) interposed between the metal current collector (331) and the cap plate (332), and the gasket (335) may be coupled to the rivet terminal (334).

[0127] In particular, in the pouch-type secondary battery (300) according to one embodiment of the present invention, compared to the cap assembly (150) described above in FIGS. 4 and 5, the cap assembly (330) has a vent portion (3321) and a fixing rib (3322) formed integrally with the cap plate (332), and since an electrolyte injection port is not required, the seal ball (159) and cover (1591) can be omitted, and since there is no concern about current conduction, the insulating plate (154) can be omitted.

[0128] Therefore, the pouch-type secondary battery (300) according to one embodiment of the present invention has the effect of reducing weight and material cost compared to the cap assembly (150) described above in FIGS. 4 and 5 through the cap assembly (330).

[0129] Additionally, in a pouch-type secondary battery (300) according to one embodiment of the present invention, the cap plate (332) may include an insulating material. This is because the cap plate (332) is interposed between a metal current collector (331) to which an electrode tab (311) is connected, and a connection terminal (333) that is electrically connected to the outside.

[0130] Additionally, in the pouch-type secondary battery (300) according to one embodiment of the present invention, the pouch (320) and the cap plate (332) may include any one of single plastic, double plastic, metal insert plastic, or film insert plastic. This is to facilitate bonding between the joint (321) of the pouch (320) and the cap plate (332).

[0131] Again, referring to FIG. 14, in a pouch-type secondary battery (300) according to one embodiment of the present invention, an electrode tab (311) can be bent while one end is fused and connected to a metal current collector (331). At this time, one end of the electrode tab (311) can be bent vertically.

[0132] This is to manufacture a pouch-type secondary battery (300) according to one embodiment of the present invention, by fusing and connecting a metal current collector (331) of a cap assembly (330) to one end of an electrode tab (311), and then bending the electrode tab (311) so that the electrode tab (311) is bent vertically.

[0133] Referring to FIGS. 17 to 20 together, in a pouch-type secondary battery (300) according to one embodiment of the present invention, an electrode tab (311) may include a positive electrode tab (311a) positioned on one side of the pouch (320) and a negative electrode tab (311b) positioned on the other side of the pouch (320). In addition, a pair of joints (321) of the pouch (320) may be formed on both sides of the pouch (320).

[0134] In addition, a pouch (320) type secondary battery (300) according to one embodiment of the present invention may include a pair of cap assemblies (330a, 330b) corresponding to a positive electrode tab (311a), a negative electrode tab (311b), and a pair of joints (321).

[0135] As illustrated in FIGS. 17 and 18, a pair of joints (321) and a pair of cap assemblies (330a, 330b) can be joined on both sides of a pouch (320) that accommodates an electrode assembly (310). Thereafter, as illustrated in FIGS. 19 and 20, an electrolyte is injected into one side of the pouch (320), and the pouch (320) is sealed and processed to produce a pouch-type secondary battery (300) according to an embodiment of the present invention.

[0136] In addition, the pouch-type secondary battery (300) according to one embodiment of the present invention is capable of being self-supporting, unlike the pouch-type secondary battery (110) described above with reference to FIG. 1, through the form of a pair of cap assemblies (330a, 330b) joined to both sides of the pouch (320) as illustrated in FIG. 20. This is advantageous in the manufacturing process and has the effect of improving process performance.

[0137] FIG. 21 is a drawing illustrating a battery pack (400) according to one embodiment of the present invention, which can be implemented by arranging a plurality of pouch-type secondary batteries (300) described above through FIGS. 14 to 20 and electrically connecting a plurality of pouch-type secondary batteries (300) through a plurality of bus bars (410).

[0138] When a battery pack is configured by electrically connecting the pouch-type secondary battery (110) described above through FIG. 1, additional processing work such as bending of the electrode lead (130) is required. In addition, an additional insulating material is required to connect the electrode lead (130) and the bus bar while fixing the bent electrode lead (130). Accordingly, when a battery pack is configured using the existing pouch-type secondary battery (100), there is a disadvantage in that the required cost is higher than that of other types of secondary batteries.

[0139] On the other hand, a pouch-type secondary battery (300) according to one embodiment of the present invention includes a cap assembly (330) connected to an electrode tab (311), and a positive electrode (420) and a negative electrode (430) can be configured through a connection terminal (333) of the cap assembly (330). In addition, as illustrated in FIG. 21, by connecting a plurality of bus bars (410) through the connection terminal (333), electrical connection is possible between a plurality of pouch-type secondary batteries (300), thereby implementing a battery pack (400) of the present invention.

[0140] Therefore, the battery pack (400) according to one embodiment of the present invention can easily form an electrical connection between a plurality of pouch-type secondary batteries (300) without additional processing work or additional parts compared to the existing ones, thereby improving productivity and reducing costs.

[0141] In summary, the pouch-type secondary battery (300) according to the present invention and the battery pack (400) including the same can have improved stability through a structure in which the electrode tab (311) is connected to the cap assembly (330) and the joint portion (321) of the pouch (320) is joined to the cap assembly (330). In addition, a vent portion (3321) is formed in the cap assembly (330) to prevent explosion or fire when the internal pressure abnormally increases in an abnormal state. In addition, the shape of the cap assembly (330) enables self-support, thereby improving process performance. In addition, the cap assembly (330) makes electrical connection between a plurality of pouch-type secondary batteries (300) simple, so that the battery pack (400) can be easily and inexpensively configured.

[0142] The above detailed description should not be construed as limiting in any respect and should be considered illustrative only. The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present invention are intended to be included within the scope of the present invention.

Claims

1. A pouch-type secondary battery in which an electrode assembly with connected electrode leads is housed in a pouch; A rectangular can having one side open to accommodate the pouch-type secondary battery; and It includes a metal current collector and a cap assembly inserted into one open side of the rectangular can, and The above electrode leads are, A prismatic secondary battery characterized in that the above-mentioned cap assembly is bent while connected to the above-mentioned metal current collector when inserted.

2. In Paragraph 1, The above electrode leads are, One end protrudes to the outside of the above pouch, and A prismatic secondary battery characterized in that one end of the electrode lead is fused and connected to the metal current collector.

3. In paragraph 2, One end of the above electrode lead, A prismatic secondary battery characterized by being folded vertically.

4. In paragraph 1, The above electrode assembly, It includes an electrode tab connected to the electrode lead, and A prismatic secondary battery characterized in that a portion of the electrode tab and the pouch accommodating the electrode tab is bent together with the electrode lead.

5. In paragraph 1, The above pouch is, A prismatic secondary battery characterized by including plastic.

6. In paragraph 1, The above electrode assembly, A prismatic secondary battery characterized by including an electrode film interposed between the above pouch and the above electrode lead.

7. In Paragraph 1, The above square can, Contains metal materials, The above cap assembly, A prismatic secondary battery characterized by including a cap plate coupled to the inner surface of one open side of the above-mentioned prismatic can.

8. In paragraph 7, The above cap plate, A prismatic secondary battery characterized by including a vent portion formed on one surface.

9. In Paragraph 8, The above vent part, A vent hole formed in the above-mentioned cap plate; and A prismatic secondary battery characterized by including a vent located in the above-mentioned vent hole.

10. In paragraph 7, The above cap plate, A prismatic secondary battery comprising a metal material and characterized by being joined to the inner surface of one open side of the prismatic can through welding.

11. In paragraph 7, The above cap assembly, A square secondary battery characterized by including an insulating plate coupled between the metal collector and the cap plate.

12. A step of injecting an electrolyte into a pouch containing an electrode assembly to which electrode leads are connected; A step of producing a pouch-type secondary battery by sealing and processing the above pouch; A step of inserting the above pouch-type secondary battery into a square can with one side open; a step of connecting the electrode lead to a metal collector of the cap assembly; and A method for manufacturing a prismatic secondary battery comprising the step of inserting the cap assembly into an open side of the prismatic can with the electrode lead connected thereto.

13. In paragraph 12, The above electrode leads are, One end protrudes to the outside of the above pouch, and A method for manufacturing a square secondary battery, characterized in that one end of the electrode lead is fused and connected to the metal current collector.

14. In Paragraph 13, One end of the above electrode lead, A method for manufacturing a square secondary battery characterized by being folded vertically.

15. In paragraph 12, The above electrode assembly, It includes an electrode tab connected to the electrode lead, and A method for manufacturing a prismatic secondary battery characterized in that a portion of the electrode tab and the pouch accommodating the electrode tab is bent together with the electrode lead.

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