Apparatus for sealing enclosure of secondary battery and method of manufacturing secondary battery

Abstract

The present invention relates to a device for sealing a secondary battery casing, a method for manufacturing a secondary battery using the same, and a secondary battery manufactured by the same. The problem to be solved is to propose a technology for preventing deformation of the sealing part and / or compliance with and maintenance of mechanical specifications that may occur during the sealing process of the secondary battery casing. To this end, according to one feature of the present invention, a secondary battery casing sealing device is provided, comprising: an electrode assembly including a plurality of electrode plates having electrode tabs formed thereon; a strip terminal welded to the electrode tabs; a sealing part that fuses the secondary battery casing, which accommodates an insulating film attached to the strip terminals, and the insulating film; and an insulating film restraining part on which the insulating film is seated to restrict positional movement of the insulating film when the sealing part fuses the secondary battery casing and the insulating film.

Description

Technology Field

[0001] The present invention relates to a secondary battery, and more specifically to a device for sealing a secondary battery casing, a method for manufacturing a secondary battery using the same, and a secondary battery manufactured by the same. Background Technology

[0003] Unlike primary batteries, which cannot be recharged, secondary batteries are batteries that can be recharged and discharged. Generally, a secondary battery includes an electrode assembly consisting of positive and negative electrode plates and a separator.

[0004] The above positive or negative electrode plate can be manufactured by undergoing a coating process in which an active material composite is coated on one or both sides of a substrate, a rolling process in which the electrode plate coated with the composite by the coating process is compressed and stretched to make the electrode plate thin and flat, a slitting process in which the electrode plate coated in multiple rows is cut in the longitudinal direction to separate it into individual electrode plates, and a notching process in which each separated electrode plate is cut in the transverse direction, unnecessary parts are removed, and tabs are formed.

[0005] An electrode assembly is manufactured by assembling multiple fabricated electrode plates. Electrical connection between the electrode assembly and an external terminal can be established through a strip terminal welded to an electrode tab (or substrate tab) formed on the uncoated portion (non-coated portion) of the electrode plate substrate. The electrode assembly and the strip terminal are housed in an outer casing, and after the electrolyte is injected, the outer casing is finally sealed.

[0006] The information described above disclosed in the background technology of this invention is intended only to enhance understanding of the background of the present invention and may therefore include information that does not constitute prior art. The problem to be solved

[0008] The present invention is intended to propose a technology for deformation of the sealing part and / or compliance with and maintenance of mechanical specifications that may occur during the sealing process of a secondary battery casing and during the use of a manufactured secondary battery product. means of solving the problem

[0010] According to one feature of the present invention for solving the above problem, a secondary battery outer casing sealing device is provided, comprising: an electrode assembly including a plurality of electrode plates having electrode tabs formed thereon; a strip terminal welded to the electrode tabs; a secondary battery outer casing containing an insulating film attached to the strip terminals; a sealing part for fusing the insulating film; and an insulating film restraining part on which the insulating film is seated to restrict the positional movement of the insulating film when the sealing part fuses the secondary battery outer casing and the insulating film.

[0011] According to some features of this secondary battery outer casing sealing device, the sealing portion may include a heat pressing portion that fuses the outer casing and a portion of the insulating film contained within the outer casing.

[0012] According to some features of this secondary battery outer casing sealing device, the insulating film restraint may include an insulating film movement blocking wall that prevents the insulating film from moving. The insulating film movement blocking wall may be located at a predetermined distance from the edge portion of the secondary battery outer casing.

[0013] In addition, this secondary battery outer casing sealing device may further include an insulating portion that prevents a portion of the insulating film from being fused to the outer casing. Here, the insulating portion may include an insulating film restraining portion. In addition, according to some features, the insulating film restraining portion may include a recess formed in the insulating portion to accommodate the insulating film. The depth of the recess may be set to accommodate at least a portion of the thickness of the insulating film. In addition, in some embodiments, the insulating portion may include a strip terminal housing portion that accommodates a strip terminal accommodated in the outer casing.

[0014] According to some features of this secondary battery outer sealing device, it is preferable that the width of the insulating film restraint portion is larger than the width of the insulating film.

[0015] In addition, according to another feature of the present invention for solving the above problem, a method for manufacturing a secondary battery is provided, comprising the steps of: providing an electrode assembly including a plurality of electrode plates having electrode tabs formed thereon; welding a strip terminal with an insulating film attached to the electrode tab; housing the electrode assembly, the strip terminal, and the insulating film in an outer material; and a sealing step of fusing the outer material and the insulating film, wherein the sealing step includes the step of restraining the insulating film to restrict the positional movement of the insulating film when fusing the outer material and the insulating film.

[0016] According to some features of this secondary battery manufacturing method, the sealing step may include a heat pressing step for fusing the outer material and a portion of the insulating film.

[0017] According to some features of this secondary battery manufacturing method, the sealing step may additionally include insulating so that a portion of the insulating film is not fused to the outer material.

[0018] According to some features of this secondary battery manufacturing method, the insulating film restraint step may include physically preventing the insulating film from moving by means of an insulating film movement blocking wall. The movement blocking wall may be located at a predetermined distance from the edge portion of the secondary battery casing.

[0019] In addition, according to another feature of the present invention for solving the above problem, a secondary battery is provided comprising: an electrode assembly including a plurality of electrode plates having electrode tabs formed thereon; a strip terminal welded to the electrode tabs and having an insulating film attached thereto; an outer casing that accommodates the electrode assembly, the strip terminal, and the insulating film; and a sealing portion in which the outer casing and the insulating film are fused, wherein the edge portion of the insulating film in the sealing portion protrudes by a preset protrusion distance from the edge portion of the outer casing.

[0020] According to some features of this secondary battery, the protrusion distance may be 0.2 to 2.0 mm.

[0021] According to some features of this secondary battery, the sealing portion may include an unfused portion in which the insulating film and the outer material are not fused.

[0022] According to some features of this secondary battery, the outer material may be a pouch for a pouch secondary battery.

[0023] According to some features of this secondary battery, the sealing portion can be fused using a secondary battery outer sealing device related to one of the features mentioned above.

[0024] The technical problems and means for solving problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems and means for solving problems can be clearly understood by those skilled in the art from the description of the invention below. Effects of the invention

[0026] According to the secondary battery outer casing sealing device and the secondary battery manufacturing method using the same of the present invention, the insulating film attached to the strip terminal can comply with and maintain the standard specifications for the protrusion distance protruding from the outer casing to enhance the sealing performance of the secondary battery outer casing and the electrical insulation performance with the strip terminal. Specifically, by including an insulating part and an insulating film restraining part in the sealing device to prevent a portion of the insulating film from being fused to the outer casing, the outer edge of the insulating film is not shrunk by heat during secondary battery manufacturing, and the movement of the insulating film is suppressed, thereby ensuring compliance with the standard specifications for the protrusion distance of the insulating film.

[0027] The effects of the present invention are not limited to the above, and other unmentioned effects will be clearly understood by those skilled in the art from the description of the invention below. Brief explanation of the drawing

[0029] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in the drawings. FIGS. 1 and FIGS. 2 schematically illustrate an electrode assembly of a secondary battery. FIG. 3 schematically shows a pouch-type secondary battery manufactured by the outer material sealing device of the present invention. FIG. 4 shows an electrode tab formed on a first electrode plate (11) and a strip terminal welded thereto. FIG. 5 is a plan view showing the pouch sealing state of a secondary battery according to some embodiment of the present invention. Figure 6 is a cross-sectional view of the XX section shown in Figure 5, viewed from the strip terminal side. Figure 7 illustrates some problems that may occur in relation to the protrusion distance of the insulating film. FIGS. 8 and FIGS. 9 schematically illustrate a tab sealer according to some embodiments of the present invention, FIG. 8 shows a side view of a tab sealer installed above and below a secondary battery pouch, and FIG. 9 shows a perspective view. Figure 10 shows the sealing of a pouch and an insulating film using the tab sealer shown in Figures 8 and 9. Figure 11 illustrates the lower sealing portion of a tab sealer. Figure 12 is an example of a secondary battery pack. Fig. 13 is an example of a car equipped with a secondary battery pack. Specific details for implementing the invention

[0030] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings.

[0031] Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0032] Therefore, it should be understood that the embodiments described in this specification and the configurations illustrated in the drawings are merely some of the most preferred embodiments of the invention and do not represent all of the technical ideas of the invention, and that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0033] Additionally, as used herein, “comprise, include” and / or “comprising, including” specify the presence of the mentioned features, numbers, steps, actions, parts, elements, and / or groups thereof, and do not exclude the presence or addition of one or more other features, numbers, actions, parts, elements, and / or groups thereof.

[0034] Additionally, to aid in understanding the invention, the attached drawings are not drawn to actual scale, and the dimensions of some components may be exaggerated. Furthermore, the same reference numerals may be assigned to identical components in different embodiments.

[0035] The statement that two subjects of comparison are "identical" means that they are "substantially identical." Therefore, substantial identity may include deviations considered low in the industry, for example, deviations within 5%. Additionally, the statement that a parameter is uniform in a given area may mean that it is uniform from an average perspective.

[0036] Although terms such as "first," "second," etc., are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless specifically stated otherwise, the first component may also be the second component.

[0037] Throughout the specification, unless specifically stated otherwise, each component may be singular or plural.

[0038] The fact that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0039] Furthermore, where one component is described as being "on," "connected to," or "coupled to" another component, it should be understood that while the components may be directly connected or coupled to each other, another component may be "interposed" between each component, or that each component may be "connected," "coupled," or "coupled" through another component.

[0040] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. Additionally, the use of “may” when describing embodiments of the invention relates to “one or more embodiments of the invention.” Expressions such as “one or more” and “one or more” preceding a list of elements modify the entire list of elements and do not modify individual elements of the list.

[0041] Throughout the specification, "A and / or B" means A, B, or A and B unless specifically stated otherwise, and "C to D" means C or more and D or less, unless specifically stated otherwise.

[0042] When syntax such as "at least one of A, B, and C", "at least one of A, B, or C", "at least one selected from the group of A, B, and C", or "at least one selected from A, B, and C" is used to specify a list of elements A, B, and C, the syntax can refer to any suitable combination.

[0043] The term "use" may be considered synonymous with the term "utilize." As used herein, terms such as "substantially," "about," and similar terms are used as terms of approximation rather than degree, and are intended to account for the inherent variation of a measured or calculated value that would be recognized by a person skilled in the art.

[0044] In this specification, terms such as first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Accordingly, the first element, component, region, layer, or section discussed below may be named the second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0045] Spatial relative terms such as "beneath," "below," "lower," "above," and "upper" may be used in the specification for ease of description to explain the relationship between one element or feature and other element(s) or feature(s) as illustrated in the drawings. Spatially relative positions are to be understood as encompassing different orientations of the device in use or operation, in addition to the orientations depicted in the figures. For example, if the device in the drawing is inverted, the other element is understood as "below" or "below," and the described element is understood as "above" or "upper" of the other element. Thus, the term "below" may encompass both the up and down directions.

[0046] The terms used in this specification are for describing embodiments of the invention and are not intended to limit the invention.

[0048] FIGS. 1 and FIGS. 2 schematically illustrate an example of an electrode assembly of a secondary battery.

[0049] The electrode assembly (10, 10') may be manufactured by stacking individual sheets of the first electrode plate (11), separator (12), and second electrode plate (13) as shown in FIG. 1, or by winding a continuous body of the first electrode plate (11), separator (12), and second electrode plate (13) as shown in FIG. 2. However, there is also a so-called Z-stack type electrode assembly (not shown) in which the first electrode plate and the second electrode plate are inserted into each space on both sides of a separator that is folded into a Z shape, as a form different from the electrode assembly (10, 10') shown in FIG. 1 and 2.

[0050] In the case of a negative electrode, the first electrode plate (11) may include an area where an active material, such as graphite or carbon, is coated on a metal substrate such as copper, a copper alloy, nickel, or a nickel alloy, and an area where no active material is coated. A first electrode tab (14) may be formed in the area where no active material is coated. Similarly, in the case of a positive electrode, the second electrode plate (13) may include an area where an active material, such as a lithium transition metal oxide, is coated on a metal substrate such as aluminum or an aluminum alloy, and an area where no active material is coated. A second electrode tab (15) may be formed in the area where no active material is coated.

[0051] The separator (12) insulates the first electrode plate (11) and the second electrode plate (13) from each other and allows lithium ion movement between them. The separator (12) can be made of, for example, a polyethylene film, a polypropylene film, a polyethylene-polypropylene film, etc.

[0052] In some embodiments, the electrode assembly (10, 10') may be housed in an outer material such as a pouch and filled with an electrolyte. In the case of a pouch-type secondary battery, the electrode assembly is housed in a pouch made of a flexible material.

[0053] A material that can be used for the electrode plate of the above electrode assembly is described.

[0054] As a positive electrode active material, a compound capable of reversible intercalation and deintercalation of lithium (a lithated intercalation compound) may be used. Specifically, one or more composite oxides of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof may be used.

[0055] The above composite oxide may be a lithium transition metal composite oxide, and specific examples include a lithium nickel-based oxide, a lithium cobalt-based oxide, a lithium manganese-based oxide, a lithium iron phosphate-based compound, a cobalt-free nickel-manganese-based oxide, or a combination thereof.

[0056] As an example, a compound represented by any one of the following chemical formulas may be used. Li a A 1-b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mn b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Co c L 1 d G eO2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NiG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn2G b O4(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G g PO4(0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe2(PO4)3(0≤f≤2); Li a FePO4(0.90≤a≤1.8).

[0057] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; L 1 is Mn, Al, or a combination thereof.

[0058] A positive electrode for a lithium secondary battery may include a current collector (substrate) and a positive electrode active material layer formed on the current collector. The positive electrode active material layer may include a positive electrode active material and may further include a binder and / or a conductive material.

[0059] The content of the above positive active material is about 90% to 99.5% by weight with respect to 100% by weight of the positive active material layer, and the content of the above binder and conductive material may each be about 0.5% to 5% by weight with respect to 100% by weight of the positive active material layer.

[0060] Al can be used for the above-mentioned current collector, but is not limited thereto.

[0061] The negative electrode active material includes a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0062] A material capable of reversibly intercalating / deintercalating the above lithium ions may be a carbon-based negative electrode active material, such as crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite, such as natural graphite or artificial graphite, and examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, etc.

[0063] As a material capable of doping and undoping the above lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material may be used. The above Si-based negative electrode active material is silicon, a silicon-carbon composite, or SiO₂. x (0 <x≤2), Si계 합금, 또는 이들의 조합일 수 있다.

[0064] The silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles.

[0065] The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer located on the surface of the core.

[0066] A negative electrode for a lithium secondary battery comprises a current collector and a negative electrode active material layer located on the current collector. The negative electrode active material layer comprises a negative electrode active material and may further comprise a binder and / or a conductive material.

[0067] For example, the negative electrode active material layer may contain about 90% to 99% by weight of negative electrode active material, about 0.5% to 5% by weight of binder, and about 0% to 5% by weight of conductive material.

[0068] As the binder, a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof may be used. When an aqueous binder is used as the cathode binder, a cellulose-based compound capable of imparting viscosity may be further included.

[0069] As the above-mentioned cathode current collector, a material selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and combinations thereof may be used.

[0070] The electrolyte for lithium secondary batteries contains a non-aqueous organic solvent and a lithium salt.

[0071] The above-mentioned non-aqueous organic solvent serves as a medium through which ions involved in the electrochemical reaction of the battery can move.

[0072] The above-mentioned non-aqueous organic solvent may be a carbonate-based, ester-based, ether-based, ketone-based, or alcohol-based solvent, an aprotic solvent, or a combination thereof, and may be used alone or in a mixture of two or more types.

[0073] In addition, when using carbonate-based solvents, cyclic carbonates and chain carbonates can be mixed and used.

[0074] Depending on the type of lithium secondary battery, a separator may be present between the positive and negative electrodes. As such a separator, polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer film of two or more layers thereof may be used.

[0075] The above separator may include a porous substrate and a coating layer comprising an organic material, an inorganic material, or a combination thereof located on one or both sides of the porous substrate.

[0076] The above organic material may include a polyvinylidene fluoride-based polymer or a (meth)acrylic-based polymer.

[0077] The above inorganic materials are Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, It may include, but is not limited to, inorganic particles selected from SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof.

[0078] The above organic and inorganic materials may exist mixed in a single coating layer, or may exist in a stacked form with a coating layer containing organic materials and a coating layer containing inorganic materials.

[0080] FIG. 3 schematically shows a pouch-type secondary battery manufactured by the outer material sealing device of the present invention.

[0081] In this pouch-type secondary battery, an electrode assembly (10) is embedded in a pouch (20) made of a flexible material. The pouch (20) consists of an electrode assembly receiving portion (20a) in which the electrode assembly (10) is received and a cover (20b). The outer portion (21a) of the electrode assembly receiving portion (20a) and the outer portion (21b) of the cover (20b) are fused together and sealed.

[0082] In FIG. 3, the electrode assembly (10) is shown as a stack type as in FIG. 1, but a wound type electrode assembly (10') as in FIG. 2 can also be applied.

[0083] The first electrode tab (14) and the second electrode tab (15) of the electrode assembly (10) can be welded to the first strip terminal (16) and the second strip terminal (17), respectively, which function as terminals exposed to the outside. The first strip terminal (16) and the second strip terminal (17) can each have a first insulating film (22) and a second insulating film (24) attached to them for insulation and airtightness of the pouch (20).

[0084] In FIG. 3, the electrode assembly (10) has a plurality of first and second electrode tabs (14, 15) (this structure is called a multi-tap structure). The plurality of first electrode tabs (14) and the plurality of second electrode tabs (15) are welded together, and a first strip terminal (16) and a second strip terminal (17) are welded to the welded first electrode tabs (14) and second electrode tabs (15), respectively. The first strip terminal (16) and the second strip terminal (17) can each be exposed to the outside of the pouch (20) as shown in FIG. 3 and serve as terminals.

[0086] FIG. 4 shows an electrode tab (14) formed on a first electrode plate (11) and a strip terminal (16) welded thereto. FIG. 4 illustrates, for convenience, one electrode tab (14) and one strip terminal (16) among a pair of electrode tabs (14, 15) and a pair of strip terminals (16, 17).

[0087] An insulating film (22) is attached to one side and the opposite side of the strip terminal (16) welded to the electrode tab (14). As shown in FIG. 3, the insulating film (22) seals the outer portions (21a, 21b) of the pouch (20) to seal the pouch (20). In addition to sealing the pouch (20), the insulating film (22) also serves to strengthen the electrical insulation (e.g., dielectric strength) between the pouch (20) and the strip terminal (16). Since the pouch (20) has a structure in which a synthetic resin layer and an aluminum layer are laminated, it is necessary to strengthen the dielectric strength between this aluminum layer and the strip terminal (16).

[0089] FIG. 5 is a plan view showing the pouch sealing state of a secondary battery according to some embodiment of the present invention.

[0090] As mentioned above, a secondary battery is manufactured by sealing the outer edge (21a) of the electrode assembly receiving portion (20a) of the pouch (20) shown in FIG. 3 and the outer edge (21b) of the cover (20b). When a portion of the strip terminals (16, 17) is exposed from the pouch (20), the insulating film (22, 24) attached to the strip terminals (16, 17) is sealed between the outer edge (21a) and the outer edge (21b) of the pouch (20).

[0091] FIG. 6 is a cross-sectional view of the XX section shown in FIG. 5, viewed from the side of the strip terminals (16, 17).

[0092] The outer edge (21a) of the electrode assembly receiving portion (20a) of the pouch (20) and the outer edge (21b) of the cover (20b) can be fused by a sealing device (not shown). At this time, the insulating film (22) attached to the first strip terminal (16) can be fused with the outer edges 21a and 21b of the pouch (20) to form sealing portions 26a and 26b, respectively. Likewise, the insulating film (24) attached to the second strip terminal (17) can also be fused with the outer edges 21a and 21b of the pouch (20) to form sealing portions 28a and 28b, respectively.

[0093] Referring again to FIG. 5, the sealing of the secondary battery pouch (20) can be performed such that the edge portion of the insulating film (22, 24) protrudes by a predetermined distance d1 and d2 from the edge portion of the pouch (20). According to some embodiments, the protrusion distances d1 and d2 of the insulating film (22, 24) after the secondary battery sealing are each designed to be about 0.2 to 2.0 mm, and preferably 1.0 mm.

[0094] As described above, the fusion between the insulating film (22, 24) and the outer edges 21a and 21b of the pouch can be performed by a pouch sealing device or by a tab sealer, which is a part thereof (see FIG. 8 and FIG. 9 described later). During the sealing of the insulating film (22, 24) using the pouch sealing device or the tab sealer (and also during the use of the manufactured secondary battery), problems related to the protrusion distance of the insulating film (22, 24) may occur. For example, problems may occur such as the insulating film (22, 24) flowing during sealing, causing the protrusion distance d1 and d2 to exceed or fall short of the specified specifications, or shrinkage of the insulating film due to heating during sealing.

[0095] FIG. 7 illustrates some problems that may occur in relation to the protrusion distance of the insulating films (22, 24).

[0096] In the case of the strip terminal (16) located on the left side of FIG. 7, the insulating film (22) shrinks due to heat during sealing, and the edge portion (23) of the shrunken insulating film (22) becomes smaller than the protrusion distance d1, causing it to go further inward than the edge of the pouch (20). In the case of the strip terminal (17) located on the right side, the edge portion (25) of the shrunken insulating film (24) shrinks to a position slightly equal to the protrusion distance d2. In either case, the insulating film (22, 24) fails to perform its function properly, and the airtightness and insulation of the pouch (20) will be reduced.

[0098] FIGS. 8 and FIGS. 9 schematically illustrate a tab sealer (50) according to some embodiments of the present invention. FIG. 8 shows a side view of a tab sealer (50) installed above and below a secondary battery pouch (20), and FIG. 9 shows a perspective view. The tab sealer (50) may be a part of a pouch sealing device (not shown).

[0099] As mentioned above, in the electrode assembly receiving portion (20a) of a pouch (20), which is one type of secondary battery outer material, an electrode assembly (10) containing a plurality of electrode plates having electrode tabs (14) formed thereon, a strip terminal (16) welded to the electrode tabs (14), and an insulating film (22) attached to the strip terminal are received. A cover (20b) covers the electrode assembly receiving portion (20a). In order to seal the cover (20b) and the electrode assembly receiving portion (20a), the outer edges 21a and 21b of the electrode assembly receiving portion (20a) and the cover (20b) can be fused with a sealing device (not shown) as shown in FIG. 3. During this sealing process, the corresponding parts of the insulating film (22, 24) and the pouch (20) can be fused by heat pressing using a pouch sealing device or a tab sealer which is a part thereof.

[0100] In FIG. 8, the tab sealer (50) may include a sealing portion (30, 40) for fusing an insulating film (22, 24) to a sealing target portion of a secondary battery outer material—e.g., an electrode assembly receiving portion (20a) and a cover (20b) of a pouch (10); and an insulating film restraining portion (44, 44' in FIG. 9) for preventing the insulating film (22, 24) from moving in order to limit the positional movement of the insulating film (22, 24) when the sealing portion (30, 40) fuses the secondary battery outer material (20) and the insulating film (22, 24).

[0101] The sealing portions (30, 40) are composed of an upper sealing portion (30) located at the upper part of the pouch (20) (e.g., above the cover (20b)) and a lower sealing portion (40) located at the lower part of the pouch (20) (e.g., below the electrode assembly receiving portion (20a)), as shown in FIG. 8, and each may include a heat pressing portion (31, 41) that applies heat to the sealing target and presses it.

[0102] In addition, in FIG. 8, the edge portion of the insulating film (22) protrudes outward by a distance d1 from the edge of the pouch (20). This protrusion distance d1 (and d2) has been explained with reference to FIG. 5 and FIG. 7. In order to ensure that the protrusion distance of the insulating film (22, 24) is within the specifications, a sealing device according to some embodiments of the present invention is provided with an insulating film restraining portion (44, 44' in FIG. 9).

[0103] In some embodiments, the insulating film restraint portion (44, 44') may include an insulating film movement blocking wall (45) that prevents the insulating film (22, 24) from moving toward the end of the strip terminal (16, 17). The insulating film movement blocking wall (45, 45') is preferably located at a distance d1 from the edge portion of the insulating film (22) and the edge portion of the secondary battery outer pouch (20) in FIG. 8.

[0104] As described above, by providing an insulating film restraint portion (44, 44') to the tab sealer (50), the insulating film (22, 24) is prevented from moving during pouch sealing, thereby maintaining the standard specifications for the protrusion distance of the insulating film (22, 24).

[0105] Additionally, the upper sealing portion (30) and the lower sealing portion (40) may additionally include an insulating portion (32, 42) that prevents a portion of the insulating film (22, 24) from being fused to the exterior material (20a, 20b). Since the insulating portion (32, 42) insulates the heat generated from the heat-pressing portion (31, 41), the outer edge portion of the insulating film (22, 24) does not shrink due to heat, thereby solving the problem described in FIG. 7 and maintaining the standard specifications of protrusion distances d1 and d2 as shown in FIG. 5.

[0106] Since the insulating part (32, 42) occupies a portion of the entire surface of the heat-pressing part (31, 41) of each of the upper sealing part (30) and the lower sealing part (40), only a portion of the pouch (20) is fused with the insulating film (22, 24) to form the fused part (27a, 27b), and a portion remains as an unfused part (29a, 29b) that is not fused.

[0107] In some embodiments, the insulating film restraint (44, 44') may be provided in the insulating portion (42) of the lower sealing portion (40) as shown in FIG. 9. Here, the insulating film restraint (44, 44') may be configured as a recessed portion that is recessed to a certain depth from the surface of the insulating portion (42) so that the insulating film (22, 24) can be accommodated. It is preferable that the depth of the recessed portion be sufficient to accommodate at least a portion of the thickness of the insulating film (22, 24). In other embodiments, the depth of the recessed portion may be equal to or greater than the thickness of the insulating film (22, 24).

[0108] As described above, by including an insulating part (32, 42) in the tab sealer (50), thermal deformation of the insulating film (22, 24) can be prevented, thereby strengthening the insulation strength between the strip terminal (16, 17) and the pouch, and maintaining the protrusion distance d1 and d2 of the insulating film (22, 24) outside the pouch.

[0109] Additionally, as shown in FIG. 9, the insulation portion (42) of the lower sealing portion (40) has a recessed strip terminal storage portion (46, 46') formed to accommodate a strip terminal (16, 17). In FIG. 9, the insulating film restraint portion (44, 44') and the strip terminal storage portion (46, 46') formed in the insulation portion (42) of the lower sealing portion (40) can be extended from the insulating film seating groove (43, 43') formed in the heat-pressing portion (41) of the lower sealing portion (40).

[0110] In another embodiment, the insulating film restraint (44, 44') and the strip terminal storage (46, 46') may be provided in the insulating portion (32) of the upper sealing portion (30), contrary to what is shown in FIG. 9. However, as shown in FIG. 9, it would be preferable for process convenience and to improve pouch sealing quality to have the insulating film restraint (44, 44') and the strip terminal storage (46, 46') provided in the insulating portion (42) of the lower sealing portion (40).

[0112] FIG. 10 shows a pouch (20) and insulating films (22, 24) being sealed using the tab sealer (50) shown in FIG. 8 and 9, and illustrates the pouch (20) and the lower sealing part (40) placed underneath it with the upper sealing part (30) of FIG. 8 and 9 removed.

[0113] An insulating film (22, 24) is stored in an insulating film restraint section (see 44, 44' in FIG. 9) formed in an insulating section (42) that occupies a part of the lower sealing section (40), and a strip terminal (16, 17) is stored in a strip terminal storage section (see 46, 46' in FIG. 9). However, in FIG. 10, the horizontal width of the insulating film restraint section (horizontal width in FIG. 10) is wider than the horizontal width of the insulating film (22, 24), so only the left and right remaining spaces (44a 44b and 44'a 44'b) of the insulating film restraint section are visible. Additionally, the horizontal width of the strip terminal storage section is wider than the horizontal width of the strip terminal (16, 17), so only the left and right remaining spaces (46a 46b and 46'a 46'b) of the strip terminal storage section are visible. The reason for leaving extra space on the left and right sides in this way is to account for the dimensional tolerances of the material and dimensional deformation during the sealing process.

[0114] In FIG. 10, it is also shown that the edge portion of the pouch (20) is configured to be located on the insulating portion (42), so that an unfused portion (29b) is formed in the pouch (20).

[0116] FIG. 11 illustrates the lower sealing portion (40) of the tab sealer (50).

[0117] An insulating part (42) occupies a portion of the heat-pressing part (41 in FIG. 9) of the lower sealing part (40), and an insulating film restraining part (44, 44') and a strip terminal receiving part (46, 46') are formed in the insulating part (42) at a position extending from the insulating film seating groove (43, 43') formed in the lower sealing part (40) (see FIG. 9).

[0118] The horizontal width W2 of the insulating film restraint portion (44, 44') formed by being embedded in the insulating portion (32, 42) is larger than the horizontal width of the insulating film (22, 24) as described above with reference to FIG. 10, in order to compensate for material dimensional tolerances and dimensional deformation during the sealing process. W2 may be approximately 3 mm larger than the horizontal width of the insulating film (22, 24), but is not limited thereto. Here, W2 is equal to the horizontal width of the insulating film seating groove (43, 43') formed in the lower sealing portion (40).

[0119] Similarly, the width W1 of the strip terminal housing (46, 46') formed by being embedded in the insulation portion (32, 42) together with the insulating film restraint portion (44, 44') is larger than the width of the strip terminal (16, 17) as described above with reference to FIG. 10. W1 may be about 3 mm larger than the width of the strip terminal (16, 17), but is not limited thereto.

[0120] The insulating film movement blocking wall (45, 45') formed in the insulating film restraint portion (44, 44') may be a vertical wall formed as the insulating film restraint portion (44, 44') is formed by being embedded in the insulating portion (32, 42), but is not limited thereto.

[0121] Element 47 shown in FIG. 11 represents a virtual line where the edge portion of the pouch (20) is located, as shown in FIG. 10. This indicates that the edge portion of the insulating film (22, 24) can protrude outward from the edge portion of the pouch (20) by the protrusion distances d1 and d2 shown in FIG. 5 due to sealing. In FIG. 11, the area corresponding to the protrusion distances d1 and d2 is indicated as P.

[0122] Meanwhile, the distance Q between the inner boundary line (49) of the insulation part (42) in FIG. 11 and the virtual line (47) where the edge part of the pouch (20) is to be located indicates that the pouch unfused part (29a, 29b) shown in FIG. 10 can be formed by the insulation part (32, 42).

[0124] A method for manufacturing a secondary battery using the aforementioned secondary battery outer sealing device is described. The following element reference numbers can be identified by referring to the drawings mentioned above, in particular, FIGS. 5 to 11.

[0125] A method for manufacturing a secondary battery according to some embodiments of the present invention comprises: providing an electrode assembly including a plurality of electrode plates having electrode tabs formed thereon; welding a strip terminal (16, 17) to which an insulating film (22, 24) is attached to the electrode tab; housing the electrode assembly, the strip terminal, and the insulating film (22, 24) in an outer material (20); and a sealing step of fusing the outer material and the insulating film (22, 24). Herein, the sealing step includes restraining the insulating film (22, 24) to restrict the positional movement of the insulating film (22, 24) when fusing the outer material (20) and the insulating film (22, 24).

[0126] In some embodiments, the sealing step may include a heat pressing step for fusing the outer material (20a, 20b) and a portion of the insulating film.

[0127] In addition, in some embodiments, the sealing step may further include insulating so that a portion of the insulating film (22, 24) is not fused to the fusion target of the exterior material (e.g., 20a, 20b).

[0128] In some embodiments, the step of restraining the insulating film (22, 24) may include physically preventing the insulating film (22, 24) from moving by means of an insulating film movement blocking wall (45, 45' in FIG. 9 and 10). The movement blocking wall (45, 45') may be located at a predetermined distance (e.g., d1, d2 in FIG. 5) from the edge portion of the secondary battery casing.

[0130] A secondary battery module can be manufactured by arranging and connecting the secondary batteries manufactured as described above in a transverse and / or longitudinal direction. The arrangement direction and number of secondary batteries can be designed to obtain desired voltage and current specifications. A secondary battery pack (70) configured to apply the secondary battery module to an actual product (e.g., a vehicle) is illustrated in FIG. 12. The secondary battery pack can be manufactured by embedding a plurality of secondary battery modules in a pack housing designed for mounting on an actual product. The pack housing may include a fastening part and an electrical output part necessary for mounting on the product, as well as related elements such as a busbar for electrical connection of the secondary batteries, a cooling unit, and an external terminal. As shown in FIG. 13, the secondary battery pack can be mounted on a vehicle. The vehicle may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle.

[0132] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs. Explanation of the symbols

[0134] 10 Electrode assembly, 11 First electrode plate, 12 Separator, 13 Second electrode plate, 14 First electrode tab, 15 Second electrode tab, 16 First strip terminal, 17 Second strip terminal, 20 Pouch, 20a Electrode assembly receiving portion, 20b Cover, 21a 21b Outer portion, 22 24 Insulating film, 26a, 26b 28a, 28b Sealing portion, 30 40 Sealing portion of tab sealer, 31 41 Heat pressing portion, 32 42 Insulating portion, 43 43' Insulating film seating groove, 44 44' Insulating film restraining portion, 45 45' Insulating film movement prevention wall, 46 46' Strip terminal receiving portion, 50 Tab sealer

Claims

Claim 1 A secondary battery outer casing sealing device comprising: an electrode assembly including a plurality of electrode plates having electrode tabs formed thereon; a strip terminal welded to the electrode tabs; a secondary battery outer casing containing an insulating film attached to the strip terminals; a sealing portion for fusing the insulating film; and an insulating film restraining portion on which the insulating film is seated to restrict the positional movement of the insulating film when the sealing portion fuses the secondary battery outer casing and the insulating film. Claim 2 A secondary battery outer casing sealing device according to claim 1, wherein the sealing portion comprises a heat-pressing portion that fuses the outer casing and a portion of the insulating film contained within the outer casing. Claim 3 A secondary battery outer casing sealing device according to claim 1, wherein the insulating film restraining portion includes an insulating film movement stopping wall that prevents the insulating film from moving. Claim 4 A secondary battery outer casing sealing device according to claim 3, wherein the insulating film movement blocking wall is located at a predetermined distance from the edge portion of the secondary battery outer casing. Claim 5 A secondary battery outer casing sealing device according to claim 1, further comprising an insulating portion that prevents a portion of the insulating film from being fused to the outer casing. Claim 6 In claim 5, the insulation part comprises the insulating film restraining part, a secondary battery outer sealing device. Claim 7 A secondary battery outer casing sealing device according to claim 5, wherein the insulating film restraining portion is formed in the insulating portion and includes a recessed portion in which the insulating film is received. Claim 8 A secondary battery outer sealing device according to claim 7, wherein the depth of the indentation of the indentation portion is set to accommodate at least a portion of the thickness of the insulating film. Claim 9 A secondary battery outer sealing device according to claim 1, wherein the width of the insulating film restraint portion is greater than the width of the insulating film. Claim 10 A secondary battery outer casing sealing device according to claim 5, wherein the insulation portion includes a strip terminal housing portion in which the strip terminal accommodated in the outer casing is received. Claim 11 A method for manufacturing a secondary battery comprising: a step of providing an electrode assembly including a plurality of electrode plates having electrode tabs formed thereon; a step of welding a strip terminal with an insulating film attached to the electrode tabs; a step of housing the electrode assembly, the strip terminal, and the insulating film in an outer material; and a sealing step of fusing the outer material and the insulating film, wherein the sealing step includes a step of restraining the insulating film to restrict the positional movement of the insulating film when fusing the outer material and the insulating film. Claim 12 A method for manufacturing a secondary battery according to claim 11, wherein the sealing step comprises a heat pressing step for fusing a portion of the outer material and the insulating film. Claim 13 A method for manufacturing a secondary battery according to claim 12, wherein the sealing step further comprises insulating the insulating film so that a portion of the insulating film is not fused to the outer material. Claim 14 A method for manufacturing a secondary battery according to claim 11, wherein the insulating film restraint step comprises physically preventing the insulating film from moving by means of an insulating film movement prevention wall. Claim 15 A method for manufacturing a secondary battery according to claim 14, wherein the movement blocking wall is located at a distance from the edge portion of the secondary battery casing by a preset distance. Claim 16 An electrode assembly comprising a plurality of electrode plates having electrode tabs formed thereon; a strip terminal welded to the electrode tabs and having an insulating film attached thereto; an outer casing accommodating the electrode assembly, the strip terminal, and the insulating film; and a sealing portion in which the outer casing and the insulating film are fused, wherein the edge portion of the insulating film in the sealing portion protrudes by a preset protrusion distance from the edge portion of the outer casing. Claim 17 A secondary battery according to claim 16, wherein the protrusion distance is 0.2 to 2.0 mm. Claim 18 A secondary battery according to claim 16, wherein the sealing portion comprises an unfused portion in which the insulating film and the outer material are not fused. Claim 19 In paragraph 16, the above-mentioned outer material is a pouch for a pouch secondary battery, a secondary battery. Claim 20 In claim 16, the sealing portion is a secondary battery fused using a secondary battery outer casing sealing device described in any one of claims 1 to 10.

Images