Prismatic secondary battery and manufacturing method therefor

Abstract

Embodiments of the present invention can provide a prismatic secondary battery comprising: an electrode assembly having an electrode lead provided on one side thereof; a pouch encompassing the electrode assembly; a prismatic can surrounding the pouch in a state in which one side thereof is opened; and a cap assembly which is coupled to the opened one side of the prismatic can and which has a terminal provided on one outer surface thereof, wherein the electrode lead passes through the cap assembly so as to be electrically connected to the terminal.

Description

Prismatic secondary battery and method for manufacturing the same

[0001] The present invention relates to a prismatic secondary battery and a method for manufacturing the same.

[0002] Generally, a secondary battery refers to a battery that converts external electrical energy into chemical energy for storage and generates electricity when needed. Examples of secondary batteries include lead-acid batteries, nickel-cadmium batteries (Ni-Cd), nickel-hydrogen batteries (NiMH), lithium-ion batteries (Li-ion), and lithium-ion polymer batteries (Li-ion polymer).

[0003] These secondary batteries are formed by coating an active material onto the surface of an electrode current collector to form a positive electrode and a negative electrode, and then forming an electrode assembly by interposing a separator between them, and then mounting it inside a pouch-type case made of a cylindrical or prismatic metal can or an aluminum laminate sheet. Then, a liquid electrolyte is injected or impregnated into the electrode assembly, or a solid electrolyte is used to manufacture it.

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

[0005] Meanwhile, secondary batteries can be classified into cylindrical, prismatic, and pouch types depending on their shape.

[0006] Pouch-type secondary batteries accommodate electrode assemblies in a flexible pouch, allowing for relatively free shape, and offer the advantages of a relatively simple manufacturing process and low manufacturing costs. In particular, pouch-type secondary batteries have the advantage of allowing for rapid electrolyte injection compared to other types of secondary batteries, as the electrolyte can be injected through one side of the pouch.

[0007] However, pouch-type secondary batteries raise concerns regarding safety compared to other types of secondary batteries because the pouch lacks rigidity and there is no vent structure to prevent explosions or fires when internal pressure rises abnormally due to the battery's abnormal condition.

[0008] Conversely, prismatic secondary batteries have an advantage in stability due to the rigidity of the prismatic can housing the electrode assembly and the aforementioned vent structure. However, since the electrolyte is injected into the interior of the prismatic can through pipes or inlets, prismatic secondary batteries have the disadvantage of poor productivity due to the increased electrolyte injection time.

[0009] Therefore, there is a need to develop a secondary battery that can ensure structural safety while improving the efficiency of the electrolyte injection process.

[0010] Embodiments of the present invention can provide a prismatic secondary battery with improved stability and a method for manufacturing the same by placing a pouch-type secondary battery inside a prismatic can having rigidity.

[0011] Embodiments of the present invention can provide a prismatic secondary battery with simplified components and a method for manufacturing the same by ensuring that the electrode lead penetrates the cap assembly and is electrically connected to the terminal.

[0012] Embodiments of the present invention can provide a prismatic secondary battery with reduced manufacturing costs and a method for manufacturing the same by forming the pouch from an inexpensive plastic material.

[0013] Embodiments of the present invention can provide a prismatic secondary battery capable of rapidly suppressing a fire during thermal runaway of the secondary battery by placing a fire extinguishing liquid in the space between the pouch and the prismatic can, and a method for manufacturing the same.

[0014] Embodiments of the present invention can provide a prismatic secondary battery and a method for manufacturing the same, wherein the electrolyte injection time is shortened by injecting the electrolyte through an open side of the pouch.

[0015] Embodiments of the present invention provide a pouch-type secondary battery with simplified components and a method for manufacturing the same by manufacturing the pouch-type secondary battery by injecting an electrolyte into the pouch and then sealing the pouch, thereby eliminating components such as a pipe for injecting the electrolyte, a seal ball for sealing the injection port, and a sealing cover.

[0016] The problems to be solved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which the present invention belongs from the description below.

[0017] Embodiments of the present invention may provide a prismatic secondary battery comprising an electrode assembly having an electrode lead on one side, a pouch surrounding the electrode assembly, a rectangular can surrounding the pouch with one side open, and a cap assembly coupled to the open side of the rectangular can and having a terminal on one outer surface, wherein the electrode lead penetrates the cap assembly and is electrically connected to the terminal.

[0018] In addition, it may include a digestive liquid disposed in the space between the pouch and the rectangular can.

[0019] In addition, the above pouch may be formed of a plastic material.

[0020] In addition, the end of the electrode lead may be positioned parallel to the end of the terminal.

[0021] In addition, the electrode lead and the terminal can be joined together by welding.

[0022] In addition, an insulating film may be disposed between the electrode lead protruding outside the pouch and the cap assembly.

[0023] Additionally, the cap assembly may further include a connector that electrically connects the electrode lead and the terminal.

[0024] In addition, an opening into which the connector is inserted may be formed inside the cap assembly and the terminal.

[0025] In addition, the end of the connector may be positioned parallel to the end of the terminal.

[0026] Additionally, the connector may include a body portion that encloses a portion of the electrode lead protruding outside the pouch, and a protrusion that protrudes from one side of the body portion, encloses the remainder of the electrode lead, and contacts the terminal.

[0027] In addition, a step may be formed along the circumference between the body part and the protrusion part.

[0028] In addition, a gasket covering an outer part of the body part and a part of the protrusion may be disposed on the above-mentioned step.

[0029] Additionally, the cap assembly may include an insulating plate that encloses a portion of the electrode lead inside the rectangular can, a cap plate disposed on one side of the insulating plate and encloses a portion of the electrode lead inside the rectangular can, and an insulating bracket disposed on one side of the cap plate and encloses a portion of the electrode lead outside the rectangular can.

[0030] Additionally, the terminal may be positioned on one side of the insulating bracket and formed to surround the remainder of the electrode lead.

[0031] In addition, the square can and the cap plate are formed of a metal material and can be joined together by welding.

[0032] Embodiments of the present invention may provide a method for manufacturing a prismatic secondary battery comprising the steps of: providing an electrode assembly having an electrode lead on one side; placing the electrode assembly and an electrolyte inside a pouch with one side open, and then sealing the open side of the pouch to provide a pouch-type secondary battery; assembling a cap assembly having a terminal on the outer side of an electrode lead protruding outside the pouch; removing the electrode lead protruding outside the cap assembly; placing a extinguishing agent and a pouch-type secondary battery inside a prismatic can with one side open; and welding the prismatic can and the cap assembly to seal them.

[0033] In addition, the step of providing the electrode assembly may provide a method for manufacturing a prismatic secondary battery comprising: a process of ultrasonically welding an electrode tab to one side of the electrode assembly; a process of laser welding the electrode tab to one side of the bent electrode lead; and a process of bending the bent portion of the electrode lead.

[0034] Additionally, the step of assembling a cap assembly having a terminal on the outer side of the electrode lead may include inserting the electrode lead protruding outside the pouch into an opening formed inside the cap assembly and the terminal, and then tack welding the connection portion between the electrode lead and the terminal.

[0035] Additionally, the step of removing the electrode lead may include a process of forming a notch on the electrode lead protruding outside the cap assembly and then removing it by applying an external force.

[0036] Additionally, the step of removing the electrode lead may include removing a portion of the electrode lead protruding outside the cap assembly, and then welding and sealing the connection portion between the electrode lead and the terminal.

[0037] According to embodiments of the present invention, by placing a pouch-type secondary battery inside a rigid prismatic can, a prismatic secondary battery with improved stability and a method for manufacturing the same can be provided.

[0038] According to embodiments of the present invention, by electrically connecting the electrode lead to the terminal through the cap assembly, a prismatic secondary battery with simplified components and a method for manufacturing the same can be provided.

[0039] According to embodiments of the present invention, by forming the pouch from an inexpensive plastic material, a prismatic secondary battery with reduced manufacturing costs and a method for manufacturing the same can be provided.

[0040] According to embodiments of the present invention, by placing a fire extinguishing liquid in the space between a pouch and a prismatic can, a prismatic secondary battery capable of rapidly suppressing a fire during thermal runaway of the secondary battery and a method for manufacturing the same can be provided.

[0041] According to embodiments of the present invention, by injecting an electrolyte through an open side of a pouch, a prismatic secondary battery with a shortened electrolyte injection time and a method for manufacturing the same can be provided.

[0042] According to embodiments of the present invention, by manufacturing a pouch-type secondary battery by injecting an electrolyte into the pouch and then sealing the pouch, configurations such as a pipe for injecting the electrolyte, a seal ball for sealing the injection port, and a sealing cover can be eliminated, thereby providing a prismatic secondary battery with simplified components and a method for manufacturing the same.

[0043] The effects of the embodiments of the present invention are not limited to those mentioned herein, and other unmentioned effects will be clearly understood by those skilled in the art from the description below.

[0044] FIG. 1 is a perspective view of a prismatic secondary battery according to one embodiment of the present invention.

[0045] Figure 2 is an exploded perspective view of Figure 1.

[0046] FIG. 3 is a schematic diagram illustrating the durability configuration of a prismatic secondary battery according to one embodiment of the present invention.

[0047] FIG. 4 is a schematic diagram showing the welding process of an electrode lead and a terminal according to one embodiment of the present invention.

[0048] FIG. 5 is a schematic diagram showing the welding process of a rectangular can and a cap plate according to one embodiment of the present invention.

[0049] FIG. 6 is a diagram illustrating the durability of a prismatic secondary battery according to another embodiment of the present invention.

[0050] FIG. 7 is a perspective view of a connector according to one embodiment of the present invention.

[0051] FIG. 8 is a flowchart of a method for manufacturing a prismatic secondary battery according to one embodiment of the present invention.

[0052] Figure 9 is a schematic diagram showing a prismatic secondary battery manufactured according to the sequence of Figure 8.

[0053] Figure 10 is a schematic diagram showing the manufacturing process of the step of preparing an electrode assembly.

[0054] FIG. 11 is a schematic diagram illustrating the manufacturing process of the step of assembling a cap assembly having a terminal on the outer side of an electrode lead.

[0055] Hereinafter, some embodiments of the present invention will be described in detail with reference to the exemplary drawings. In assigning reference numerals to the components of each drawing, the same components may have the same reference numeral as much as possible, even if they are shown in different drawings. Furthermore, in describing the present invention, if it is determined that a detailed description of related known components or functions may obscure the essence of the present invention, such detailed description may be omitted. Where terms such as "comprising," "having," or "consisting of" are used in this specification, other parts may be added unless "only" is used. Where a component is expressed in the singular, it may include a plural unless there is a special explicit description otherwise.

[0056] Additionally, terms such as first, second, A, B, (a), (b), etc., may be used when describing the components of the present invention. These terms are used merely to distinguish the components from other components, and the essence, order, sequence, or number of the components are not limited by such terms.

[0057] In describing the positional relationship of components, where it is stated that two or more components are "connected," "combined," or "joined," it should be understood that while the two or more components may be directly "connected," "combined," or "joined," they may also be "connected," "combined," or "joined" with other components "intervened." Here, the other components may be included in one or more of the two or more components that are "connected," "combined," or "joined" with one another.

[0058] In describing the temporal flow relationship regarding components, methods of operation, or methods of production, for example, when the temporal or sequential relationship is described using "after," "following," "next," or "before," it may include cases where the relationship is not continuous unless "immediately" or "directly" is used.

[0059] Meanwhile, where numerical values ​​or corresponding information regarding a component (e.g., levels, etc.) are mentioned, even without separate explicit notation, the numerical values ​​or corresponding information may be interpreted as including a range of error that may occur due to various factors (e.g., process factors, internal or external shocks, noise, etc.).

[0060] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings.

[0061] FIG. 1 is a perspective view of a prismatic secondary battery according to one embodiment of the present invention, FIG. 2 is an exploded perspective view of FIG. 1, and FIG. 3 is a diagram schematically illustrating the durability configuration of a prismatic secondary battery according to one embodiment of the present invention.

[0062] Referring to FIGS. 1 to 3, the prismatic secondary battery (100) may include an electrode assembly (110), a pouch (120), a prismatic can (130), and a cap assembly (140).

[0063] The electrode assembly (110) may be configured to enable charging and discharging by having a structure in which a plurality of electrodes and a separator are stacked, and an electrode lead (113) may be provided on one side. For example, the electrode assembly (110) may be formed as one selected from a jelly roll type in which a separator is interposed between a sheet-type positive electrode and a negative electrode coated with an active material and wound, a stack type in which a plurality of positive electrodes and negative electrodes are sequentially stacked with a separator interposed, and a stack & folding type in which unit cells of the stack type are wound into a long separator film.

[0064] The electrode assembly (110) includes an electrode tab (112) connected to an electrode (111), and an electrode lead (113) may be connected to the electrode tab (112). For example, the electrode (111) may be joined to the electrode tab (112) by ultrasonic welding, and the electrode lead (113) may be joined to the electrode tab (112) by laser welding.

[0065] The electrode assembly (110) may further include an insulating film (114) that wraps a portion of the electrode lead (113). For example, the insulating film (114) may be placed between the electrode lead (113) protruding outside the pouch (120) and the cap assembly (140). Accordingly, safety can be ensured by insulating the electrode lead (113) and the rectangular can (130) through the insulating film (114).

[0066] In the present embodiment, the prismatic secondary battery (100) may be configured as a bidirectional secondary battery having electrode leads (113) of opposite polarity provided in the same direction on one side of the electrode assembly (110). However, the structure of the prismatic secondary battery (100) is not limited thereto, and may be configured as a bidirectional secondary battery having electrode leads (113) of opposite polarity provided on one side and the other side of the electrode assembly (110), respectively.

[0067] The pouch (120) may be formed to enclose the electrode assembly (110). For example, the pouch (120) may be formed in a box shape with one side open, and may be sealed by fusing the open side of the pouch (120) while the electrode assembly (110) and electrolyte are contained inside. A pouch-type secondary battery (1) can be manufactured by the fusing process of such a pouch (120). At this time, a part of the electrode lead (113) equipped with an insulating film (114) may protrude to one side of the pouch (120) and be exposed to the outside.

[0068] The pouch (120) can be heat-fused and bonded onto the insulating film (114). Accordingly, the sealing force between the electrode lead (113) and the pouch (120) can be improved.

[0069] The electrolyte provided inside the pouch (120) may be composed of a polymer electrolyte selected from the group consisting of polyethylene glycol dimethyl ether, bisphenol A, polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphate ester polymers, polyagitation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, polymers containing ionic dissociators, and combinations thereof, but is not limited thereto.

[0070] In this way, since the electrolyte can be injected through the open side of the pouch (120), there is an advantage in that the time for injecting the electrolyte is shortened. That is, in the case of a general prismatic secondary battery, the electrode assembly (110) is placed inside a metal case without the configuration of a pouch (120), and then the electrolyte is injected through an injection port formed on one side of the case, so the time for injecting the electrolyte is long and there is a disadvantage that a seal ball and a sealing cover to seal the injection port must be provided separately.

[0071] On the other hand, the prismatic secondary battery (100) according to the present invention has the advantage of simplifying parts by accommodating an electrode assembly (110) and an electrolyte inside the pouch (120) through an open side of the pouch (120), thereby shortening the time for injecting the electrolyte and eliminating the configuration of the seal ball and sealing cover.

[0072] The pouch (120) may be formed from a plastic material. Generally, the pouch (120) is configured with a metal film interposed therein to protect the electrode assembly (110) and to ensure heat dissipation and rigidity. However, since the pouch (120) according to the present invention is protected by the rectangular can (130) described later, the metal film can be removed and the pouch (120) can be manufactured from an inexpensive plastic. Therefore, there is an advantage in that manufacturing costs can be reduced.

[0073] The material of the pouch (120) is not limited to that exemplified and can be implemented in various materials. For example, the pouch (120) may be made of one selected from a single-material plastic, a dual-material plastic, or an insert-injection metal plastic formed by insert injection with a metal support structure.

[0074] The rectangular can (130) forms the exterior of the rectangular secondary battery (100) and can protect the pouch (120) from external stimuli by accommodating the pouch (120) inside.

[0075] The rectangular can (130) may be formed to wrap around the pouch (120) with one side open. For example, the rectangular can (130) may be formed in a box shape with one side open and may be formed of a metal material to ensure rigidity.

[0076] The cap assembly (140) can be attached to an open side of the rectangular can (130) to seal the internal space of the rectangular can (130). The cap assembly (140) can be joined to one side of the rectangular can (130) by welding, and a terminal (150) electrically connected to an external circuit can be provided on the outer surface.

[0077] In this embodiment, the electrode lead (113) can penetrate the cap assembly (140) and be electrically connected to the terminal (150). For example, the electrode lead (113) protruding outside the pouch (120) can be inserted into an opening (OP) formed inside the cap assembly (140) and the terminal (150). At this time, the end of the electrode lead (113) is positioned parallel to the end of the terminal (150) so that the exterior can be formed smoothly.

[0078] Due to the structure of the electrode lead (113), the electrode lead (113) can come into contact with the terminal (150) and be electrically connected to it. Thus, the prismatic secondary battery (100) can supply electricity to an external circuit through the electrode lead (113) and the terminal (150).

[0079] The cap assembly (140) may include an insulating plate (141), a cap plate (142), and an insulating bracket (143).

[0080] An insulating plate (141) may be formed to surround a portion of the electrode lead (113) inside the rectangular can (130). The insulating plate (141) may include an electrically insulating material and may prevent the electrode assembly (110) and the rectangular can (130) from being unintentionally short-circuited.

[0081] A cap plate (142) is positioned on one side of an insulating plate (141) and can be formed to surround a portion of an electrode lead (113) inside a rectangular can (130). For example, the cap plate (142) may be formed of a metal material and joined to the rectangular can (130) by welding. Through this welding process, the interior of the rectangular can (130) can be sealed.

[0082] The cap plate (142) may include a vent hole (142a). Accordingly, when the internal pressure of the prismatic secondary battery (100) rises, the gas inside the prismatic can (130) is released to the outside through the vent hole (142a), thereby preventing an explosion or fire.

[0083] An insulating bracket (143) is positioned on one side of the cap plate (142) and can be formed to wrap around a portion of the electrode lead (113) on the outside of the rectangular can (130). For example, the insulating bracket (143) may include an electrically insulating material and can cover and protect the electrode lead (113) protruding outside the rectangular can (130).

[0084] The terminal (150) may be formed to be positioned on one side of the insulating bracket (143) and to surround the remainder of the electrode lead (113). In this way, as the terminal (150) and the electrode lead (113) come into contact and are electrically connected, electricity can be supplied to the external circuit of the prismatic secondary battery (100) through the electrode lead (113) and the terminal (150).

[0085] Referring to FIGS. 2 and 3, the prismatic secondary battery (100) may include a fire extinguishing liquid (10) disposed in the space between the pouch (120) and the prismatic can (130). For example, the fire extinguishing liquid (10) may include at least one selected from the group consisting of a halogen compound, a solid aerosol fire extinguisher material, a gas generator, and a fluorinated ketone compound.

[0086] In this way, as the fire extinguishing liquid (10) is placed in the space between the pouch (120) and the rectangular can (130), the fire can be quickly suppressed during thermal runaway of the secondary battery.

[0087] Meanwhile, the extinguishing agent (10) can be injected into the interior of the square can (130) through an open side of the square can (130). Accordingly, compared to the case where the extinguishing agent (10) is injected through a separate pipe or injection port, there is an advantage in that the injection time of the extinguishing agent (10) is shortened.

[0088] FIG. 4 is a schematic diagram showing the welding process of an electrode lead and a terminal according to one embodiment of the present invention.

[0089] Referring to FIG. 4, the electrode lead (113) and the terminal (150) can be joined together by welding. For example, the electrode lead (113) protruding from one side of the pouch (120) can be inserted into the opening (OP) formed in the cap assembly (140) and the terminal (150), and then the electrode lead (113) and the terminal (150) can be joined by welding the connection portion between the electrode lead (113) and the terminal (150).

[0090] FIG. 5 is a schematic diagram showing the welding process of a rectangular can and a cap plate according to one embodiment of the present invention.

[0091] Referring to FIG. 5, the rectangular can (130) and the cap plate (142) are formed of a metal material and can be joined together by welding. For example, after placing the fire extinguishing liquid (10) and the pouch-type secondary battery (1) inside the rectangular can (130) through the open side of the rectangular can (130), the rectangular can (130) and the cap plate (142) can be joined by welding the connection portion between the rectangular can (130) and the cap plate (142).

[0092] Accordingly, the interior of the rectangular can (130) can be sealed, and the extinguishing liquid (10) injected into the interior of the rectangular can (130) can be prevented from leaking out.

[0093] FIG. 6 is a drawing illustrating the durability of a prismatic secondary battery according to another embodiment of the present invention, and FIG. 7 is a perspective view of a connector according to one embodiment of the present invention. In this embodiment, the differences from the previously described embodiment will be explained in detail.

[0094] Referring to FIGS. 6 and 7, the cap assembly (140) of the prismatic secondary battery (200) may further include a connector (144) that electrically connects the electrode lead (113) and the terminal (150).

[0095] For example, the connector (144) may be formed to wrap around the electrode lead (113) protruding outside the pouch (120). Accordingly, the rigidity of the electrode lead (113), which has a thin thickness, can be supplemented through the connector (144).

[0096] An opening (OP) into which a connector (144) is inserted may be formed inside the cap assembly (140) and the terminal (150), and the connector (144) may pass through the opening (OP) and come into contact with the terminal (150) to be electrically connected. At this time, the end of the connector (144) is positioned parallel to the end of the terminal (150) so that the exterior can be formed smoothly.

[0097] The connector (144) may be formed of a metal material and may include a body part (41) and a protrusion (42).

[0098] The body portion (41) may be formed to surround a portion of the electrode lead (113) protruding outside the pouch (120). For example, the body portion (41) may be formed in the shape of a square plate with a through hole (144a) formed inside, and the electrode lead (113) protruding outside the pouch (120) is inserted into the through hole (144a), so that the body portion (41) surrounds a portion of the electrode lead (113).

[0099] The protrusion (42) protrudes to one side of the body part (41) to surround the remainder of the electrode lead (113) and can come into contact with the terminal (150). For example, the protrusion (42) may be formed in the shape of a square column with a through hole (144a) formed inside, and the remainder of the electrode lead (113) protruding outside the pouch (120) is inserted into the through hole (144a), so that the protrusion (42) surrounds the remainder of the electrode lead (113).

[0100] The end of the protrusion (42) is positioned parallel to the end of the terminal (150) so as to come into contact with the terminal (150). Accordingly, the outer surface of the protrusion (42) and the inner surface of the terminal (150) can come into contact with each other and be electrically connected.

[0101] Meanwhile, a step (144b) may be formed along the circumference between the body part (41) and the protrusion (42). For example, the horizontal area of ​​the body part (41) may be formed larger than the horizontal area of ​​the protrusion (42), thereby forming a step (144b) along the circumference between the body part (41) and the protrusion (42). This step (144b) structure can serve as a stopper when inserting the connector (144) into the opening (OP) of the cap assembly (140).

[0102] A gasket (160) that encloses a part of the body portion (41) and a part of the protrusion (42) may be disposed on the step (144b). For example, the gasket (160) may be disposed between a connector (144) formed of a metal material and a cap plate (142) to insulate the connector (144) and the cap plate (142).

[0103] FIG. 8 is a flowchart of a method for manufacturing a prismatic secondary battery according to an embodiment of the present invention, FIG. 9 is a schematic diagram showing a prismatic secondary battery manufactured according to the sequence of FIG. 8, FIG. 10 is a schematic diagram showing the manufacturing process of the step of providing an electrode assembly, and FIG. 11 is a schematic diagram showing the manufacturing process of the step of assembling a cap assembly having a terminal on the outer side of an electrode lead.

[0104] Referring to FIGS. 8 to 11, a method for manufacturing a prismatic secondary battery (S100) may include the steps of: providing an electrode assembly (S110); providing a pouch-type secondary battery (S120); assembling a cap assembly having a terminal on the outer side of an electrode lead (S130); removing an electrode lead (S140); placing a fire extinguishing liquid and a pouch-type secondary battery inside a prismatic can (S150); and welding the prismatic can and the cap assembly together to seal them (S160).

[0105] In the step (S110) of providing an electrode assembly, an electrode assembly (110) having an electrode lead (113) on one side may be provided. For example, the electrode assembly (110) may include an electrode lead (113) formed to protrude longly from one side of an electrode (111), and a portion of the electrode lead (113) may be covered by an insulating film (114).

[0106] Referring to FIG. 10, the step (S110) of providing an electrode assembly may include ultrasonically welding an electrode tab (112) to one side of an electrode (111), laser welding the electrode tab (112) to one side of a bent electrode lead (113), and bending the bent portion of the electrode lead (113). Through this process, the electrode lead (113) can be electrically connected to the electrode tab (112), and the electrode (111) and the electrode lead (113) can be arranged vertically in an elongated manner in the drawing.

[0107] In this embodiment, the electrode lead (113) and the electrode tab (112) are laser welded while the electrode lead (113) is provided alone, but it is also possible to laser weld the electrode lead (113) and the electrode tab (112) while the cap assembly (140) is provided on one side of the electrode lead (113).

[0108] In the step (S120) of providing a pouch-type secondary battery, an electrode assembly (110) and an electrolyte are placed inside a pouch (120) with one side open, and then the open side of the pouch (120) is sealed to provide a pouch-type secondary battery (1). For example, the open side of the pouch (120) can be heat-fused and bonded onto an insulating film (114) that surrounds the electrode lead (113), thereby sealing the space between the electrode lead (113) and the pouch (120).

[0109] In this way, when the electrolyte is injected into the open side of the pouch (120) before sealing the pouch (120), the time for injecting the electrolyte can be shortened compared to when the electrolyte is injected through a pipe or an injection port.

[0110] In the step (S130) of assembling a cap assembly having a terminal on the outer side of an electrode lead, a cap assembly (140) having a terminal (150) on the outer side of an electrode lead (113) protruding outside the pouch (120) can be assembled.

[0111] Referring to FIG. 11, the step (S130) of assembling a cap assembly having a terminal on the outer side of an electrode lead may include inserting the electrode lead (113) protruding outside of the pouch (120) into an opening (OP) formed inside the cap assembly (140) and the terminal (150), and then tack welding the connection portion between the electrode lead (113) and the terminal (150).

[0112] In this way, as the connection portion between the electrode lead (113) and the terminal (150) is temporarily welded, the cap assembly (140) can be prevented from detaching from the electrode lead (113) in the step described later.

[0113] In the step of removing the electrode lead (S140), the electrode lead (113) protruding outside the cap assembly (140) can be removed through a notch process. For example, the step of removing the electrode lead (S140) may include a process of removing the electrode lead (113) protruding outside the cap assembly (140) by forming a notch on the electrode lead (113) and then applying an external force. That is, the electrode lead (113) protruding outside the cap assembly (140) can be removed by forming a cut line at the removal site of the electrode lead (113) and then bending it.

[0114] In this way, as a portion of the electrode lead (113) protruding outside the cap assembly (140) is removed, the end of the electrode lead (113) and the end of the terminal (150) can be formed side by side.

[0115] The step of removing the electrode lead (S140) may include removing a portion of the electrode lead (113) protruding outside the cap assembly (140), and then welding and sealing the connection portion between the electrode lead (113) and the terminal (150). That is, by welding the connection portion between the electrode lead (113) and the terminal (150) that was tack-welded in the step of assembling the cap assembly having a terminal on the outside of the electrode lead (S130), the airtightness inside the pouch (120) can be improved.

[0116] In the step (S150) of placing the fire extinguishing liquid and the pouch-type secondary battery inside the rectangular can, the fire extinguishing liquid (10) and the pouch-type secondary battery (1) can be placed inside the rectangular can (130), which is formed of a metal material and has one side open. Through this process, the fire extinguishing liquid (10) can be placed between the rectangular can (130) and the pouch (120). Therefore, if thermal runaway occurs in the secondary battery, the fire can be quickly suppressed.

[0117] In the step (S160) of welding and sealing the square can and the cap assembly, the square can (130) and the cap assembly (140) can be sealed by seam welding. For example, after placing the cap plate (142) on the open side of the square can (130), the connection portion between the square can (130) and the cap assembly (140) can be joined by seam welding. Accordingly, the fire extinguishing liquid (10) placed inside the square can (130) can be prevented from leaking out.

[0118] As described above, the stability of the prismatic secondary battery (100) can be improved by placing the pouch-type secondary battery (1) inside a prismatic can (130) having rigidity.

[0119] In addition, since the electrode lead (113) passes through the cap assembly (140) and is electrically connected to the terminal (150), a separate part for electrically connecting the electrode lead (113) and the terminal (150) is not required, so the parts can be simplified.

[0120] In addition, by forming the pouch (120) from a low-cost plastic material, manufacturing costs can be reduced.

[0121] In addition, by placing the fire extinguishing liquid (10) in the space between the pouch (120) and the rectangular can (130), the fire can be quickly suppressed during thermal runaway of the secondary battery.

[0122] In addition, by injecting the electrolyte through the open side of the pouch (120), the injection time of the electrolyte can be shortened.

[0123] In addition, by manufacturing a pouch-type secondary battery (1) by injecting an electrolyte into the pouch (120) and then sealing the pouch (120), the configuration of a pipe for injecting the electrolyte, a seal ball for sealing the injection port, and a sealing cover can be eliminated, which has the advantage of simplifying the parts.

[0124] The foregoing description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications and variations within the scope of the essential characteristics of the present invention. Furthermore, the embodiments disclosed in the present invention are intended to explain, not limit, the technical concept of the present invention, and thus the scope of the technical concept of the present invention is not limited by these embodiments.

Claims

1. An electrode assembly having an electrode lead on one side; A pouch enclosing the above electrode assembly; A rectangular can that encloses the pouch with one side open; and It includes a cap assembly coupled to one open side of the above-mentioned rectangular can and having a terminal on one outer surface, A rectangular secondary battery in which the electrode lead penetrates the cap assembly and is electrically connected to the terminal.

2. In Paragraph 1, A prismatic secondary battery comprising a digestion liquid disposed in the space between the above pouch and the above prismatic can.

3. In Paragraph 1, The above pouch is a prismatic secondary battery formed from plastic material.

4. In Paragraph 1, A rectangular secondary battery in which the end of the electrode lead is positioned parallel to the end of the terminal.

5. In Paragraph 1, A prismatic secondary battery in which the electrode lead and the terminal are joined together by welding.

6. In Paragraph 1, A rectangular secondary battery in which an insulating film is disposed between the electrode lead protruding outside the pouch and the cap assembly.

7. In Paragraph 1, The above cap assembly is a prismatic secondary battery further comprising a connector that electrically connects the electrode lead and the terminal.

8. In Paragraph 7, A rectangular secondary battery having an opening formed inside the cap assembly and the terminal into which the connector is inserted.

9. In Paragraph 7, The end of the connector is a rectangular secondary battery arranged parallel to the end of the terminal.

10. In Paragraph 7, The above connector is, A body portion that encloses a portion of the electrode lead protruding to the outside of the pouch, and A rectangular secondary battery comprising a protrusion that protrudes from one side of the body portion, surrounds the remainder of the electrode lead, and contacts the terminal.

11. In Paragraph 10, A rectangular secondary battery in which a step is formed along the circumference between the body portion and the protrusion portion.

12. In Paragraph 11, A rectangular secondary battery having a gasket disposed on the above-mentioned step that encloses a portion of the outer side of the body part and a portion of the above-mentioned protrusion.

13. In Paragraph 1, The above cap assembly is, An insulating plate that surrounds a portion of the electrode lead inside the above-mentioned rectangular can, and A cap plate disposed on one side of the insulating plate and surrounding a portion of the electrode lead inside the rectangular can, and A rectangular secondary battery comprising an insulating bracket disposed on one side of the cap plate and covering a portion of the electrode lead on the outside of the rectangular can.

14. In Paragraph 13, The above terminal is a rectangular secondary battery positioned on one side of the insulating bracket and encloses the remainder of the electrode lead.

15. In Paragraph 13, A prismatic secondary battery in which the above-mentioned prismatic can and the above-mentioned cap plate are formed of a metal material and joined together by welding.

16. A step of providing an electrode assembly having an electrode lead on one side; A step of providing a pouch-type secondary battery by placing the electrode assembly and electrolyte inside a pouch with one side open, and then sealing the open side of the pouch; A step of assembling a cap assembly having a terminal on the outer side of an electrode lead protruding outside the pouch; A step of removing the electrode lead protruding outside the cap assembly; A step of placing a fire extinguishing liquid and a pouch-type secondary battery inside a rectangular can with one side open; and A step of welding and sealing the above-mentioned rectangular can and the above-mentioned cap assembly; A method for manufacturing a prismatic secondary battery including 17. In Paragraph 16, The step of providing the above electrode assembly is, The process of ultrasonically welding an electrode tab to one side of an electrode, and A process of laser welding one side of the electrode lead and the electrode tab, and A method for manufacturing a prismatic secondary battery comprising a process of bending a bent portion of the electrode lead.

18. In Paragraph 16, The step of assembling a cap assembly having a terminal on the outer side of the electrode lead is: A method for manufacturing a prismatic secondary battery comprising the process of inserting the electrode lead protruding outside the pouch into an opening formed inside the cap assembly and the terminal, and then tack welding the connection portion between the electrode lead and the terminal.

19. In Paragraph 16, The step of removing the electrode lead is, A method for manufacturing a secondary battery comprising the process of forming a notch on the electrode lead protruding outside the cap assembly and then removing it by applying an external force.

20. In Paragraph 16, The step of removing the electrode lead is, A method for manufacturing a secondary battery comprising the process of removing a portion of the electrode lead protruding outside the cap assembly and then welding and sealing the connection portion between the electrode lead and the terminal.

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