Secondary battery and manufacturing method thereof

Abstract

A secondary battery is provided, which includes a stacked electrode assembly in which a plurality of unit cells are stacked in a first direction and has electrode leads on both side edges in a second direction perpendicular to the first direction; a multifunctional terminal block (MTB) provided on both side edges of the stacked electrode assembly; and a laminate sheet wrapping the sides of the stacked electrode assembly, wherein the MTB includes a fusion resin layer having a locally increased thickness on the side.

Description

[Technical Field]

[0001] The present invention relates to a secondary battery and a manufacturing method thereof, and more specifically to a secondary battery with improved safety and excellent productivity, and a manufacturing method thereof.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0167377, filed November 28, 2023, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference. [Background technology]

[0003] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. Secondary batteries are widely used as energy sources for a variety of wireless devices, such as handsets, laptops, and wireless vacuum cleaners. In recent years, improvements in energy density and economies of scale have dramatically reduced the manufacturing cost per unit capacity of secondary batteries. As the driving range of battery electric vehicles (BEVs) has increased to the same level as fuel-powered vehicles, the primary use of secondary batteries has shifted from mobile devices to mobility.

[0004] As secondary batteries are used in mobility, there is a growing demand for their safety. Research into technologies to improve the safety of secondary batteries is essential, as a fire or other accident involving a secondary battery used in mobility could put the driver's life at risk. Summary of the Invention [Problem to be solved by the invention]

[0005] A first technical problem that the present invention aims to achieve is to provide a secondary battery with improved safety and excellent productivity.

[0006] A second technical problem to be achieved by the present invention is to provide a method for producing a secondary battery with improved safety and excellent productivity. [Means for solving the problem]

[0007] To achieve the first technical objective, the present invention provides a secondary battery including a stacked electrode assembly in which a plurality of unit cells are stacked in a first direction and have electrode leads on both side edges in a second direction perpendicular to the first direction; a multifunctional terminal block (MTB) provided on both side edges of the stacked electrode assembly; and a laminate sheet wrapping the sides of the stacked electrode assembly, wherein the MTB includes a fusion resin layer having a locally increased thickness on the side.

[0008] In some embodiments, the interleaving portion of the laminate sheet may be positioned at a location where the fusion resin layer has a locally increased thickness.

[0009] In some embodiments, the fusion resin layer is a polymer film, and the locations where the fusion resin layer has a locally increased thickness may be due to the polymer film being coated more times than other locations.

[0010] In some embodiments, the fusion resin layer may include an extension that extends from the edge of the laminate sheet along the side of the MTB.

[0011] In some embodiments, the thickness of the fusion resin layer at the position in the extension portion where the locally increased thickness is present may be about 1.8 to about 2.2 times the thickness of the fusion resin layer at other positions in the extension portion.

[0012] In some embodiments, the interleaving portion may be positioned substantially at the center of the secondary battery in the first direction.

[0013] In some embodiments, the fused resin layer is a polymer ring fused to the edge of the MTB housing of the MTB, and the location where the fused resin layer has a locally increased thickness may be a portion where tension was applied to the polymer ring when the polymer ring was fused to the edge of the MTB housing.

[0014] In some embodiments, the fusion resin layer can extend at least partially between the interleaving sections.

[0015] In some embodiments, the length by which the fusion resin layer extends between the interleaving portions may be about 0.1 mm to about 2 mm.

[0016] To achieve the second technical objective, the present invention provides a method for manufacturing a secondary battery, the method comprising the steps of: attaching a multifunctional terminal block (MTB) to both end portions of a stacked electrode assembly, the stacked electrode assembly including a plurality of unit batteries stacked in a first direction and having electrode leads at both end portions in a second direction perpendicular to the first direction; forming a fusion resin layer on an edge of an MTB housing of the MTB; and bonding the laminate sheet to the fusion resin layer so as to wrap around the side of the stacked electrode assembly, wherein the fusion resin layer has a locally increased thickness, and the laminate sheet has a paper-insertion section at the position where the fusion resin layer has a locally increased thickness.

[0017] In some embodiments, forming the fusion resin layer may include locally forming an overlapping layer of polymer film.

[0018] In some embodiments, the polymer film can be configured to surround and then locally overlap the sides of the MTB housing.

[0019] In some embodiments, the step of forming the fused resin layer may include providing a polymer ring on the edge of the MTB housing having an inner length longer than the length of the outer peripheral surface of the MTB housing, fusing the polymer ring from one side of the MTB housing onto a side surface of the MTB housing, and fusing the remaining lengths of the polymer ring to each other.

[0020] In some embodiments, in the step of fusing the remaining lengths of the polymer rings together, the locations where the polymer rings are fused together can substantially coincide with the locations where the laminate sheets have interleaving sections.

[0021] In some embodiments, an electrode terminal portion electrically connected to an electrode lead of the stacked electrode assembly and a bus bar electrically connecting the electrode lead of the stacked electrode assembly and the electrode terminal portion are provided within the MTB housing, and the laminate sheet includes a flexible metal layer, an inner resin layer provided on one side of the metal layer, and an outer resin layer provided on the other side of the metal layer, and the inner resin layer may include cast polypropylene (CPP). [Effects of the Invention]

[0022] The secondary battery of the present invention has excellent sealing reliability, thereby improving safety, and is easy to manufacture, thereby improving productivity.

[0023] The effects that can be obtained from the exemplary embodiments of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood from the following description by a person having ordinary skill in the art to which the exemplary embodiments of the present disclosure belong. In other words, unintended effects accompanying the implementation of the exemplary embodiments of the present disclosure can also be derived from the exemplary embodiments of the present disclosure by a person having ordinary skill in the art. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a perspective view showing a main part of a secondary battery according to an embodiment of the present invention; [Figure 2] 2 is a partial perspective view showing an enlarged view of a part of the secondary battery of FIG. 1. FIG. [Figure 3] 2 is a schematic perspective view showing the secondary battery of FIG. 1 with a laminate sheet removed. FIG. [Figure 4] 4 is a side view showing the secondary battery according to one embodiment of the present invention as viewed in a second direction. FIG. [Figure 5] FIG. 5 is a partially enlarged view of a portion indicated by P in FIG. 4. [Figure 6] 10 is a side view showing a secondary battery according to another embodiment of the present invention as viewed in a second direction. FIG. [Figure 7] 1 is a partially exploded perspective view showing a joining method of laminate sheets of a secondary battery according to an embodiment of the present invention; [Figure 8] 1 is a partial cross-sectional view of a laminate sheet according to one embodiment of the present invention. [Figure 9] 3 is a schematic diagram showing a main part of the extension exposed from the edge of the laminate sheet. FIG. [Figure 10] 8 is a cross-sectional view showing a main part of a cross section of a first MTB and a laminate sheet according to one embodiment of the present invention taken along line XX' in FIG. 7. [Figure 11] FIG. 10 is a partially exploded perspective view showing a method for joining laminate sheets of a secondary battery according to another embodiment of the present invention. [Figure 12] 1 is a flowchart showing a method for manufacturing a secondary battery according to an embodiment of the present invention. [Figure 13] 1A and 1B are perspective and side views illustrating a method for manufacturing a secondary battery according to an embodiment of the present invention. [Figure 14] 1A and 1B are perspective and side views illustrating a method for manufacturing a secondary battery according to an embodiment of the present invention. [Figure 15] 1 is a diagram showing an embodiment of a method for forming a fusion resin layer. [Figure 16]1 is a diagram showing an embodiment of a method for forming a fusion resin layer. [Figure 17] 1 is a diagram showing an embodiment of a method for forming a fusion resin layer. [Figure 18] 10 is a diagram showing another embodiment of a method for forming a fusion resin layer. [Figure 19] 1A and 1B are perspective and side views illustrating a method for manufacturing a secondary battery according to an embodiment of the present invention. [Figure 20] 1 is a schematic perspective view of a battery pack according to an embodiment of the present invention; [Figure 21] FIG. 21 is an exploded perspective view showing a schematic configuration of the battery pack of FIG. 20. [Figure 22] 22 is a perspective view showing the battery cell of FIG. 21 seated in a pack housing. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0025] Preferred embodiments of the inventive concept will now be described in detail with reference to the accompanying drawings. However, the embodiments of the inventive concept can be modified into various different forms, and the scope of the inventive concept should not be construed as being limited by the embodiments described below. The embodiments of the inventive concept are preferably construed as being provided to more completely explain the inventive concept to those of ordinary skill in the art. The same reference numerals refer to the same elements throughout. Furthermore, various elements and regions in the drawings are drawn schematically. Therefore, the inventive concept is not limited by the relative sizes or spacings depicted in the accompanying drawings.

[0026] Terms such as "first," "second," etc. may be used to describe various components, but the components are not limited by these terms. These terms are used only to distinguish one component from another. For example, a first component may be designated a "second component," and vice versa, without departing from the scope of the inventive concept.

[0027] The terms used in this application are merely used to describe specific embodiments and are not intended to limit the concept of the present invention. A singular expression includes a plural expression unless the context clearly indicates otherwise. In this application, expressions such as "comprise" or "have" are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, and are understood not to preclude the presence or possibility of addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0028] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the concept of the present invention belongs. Furthermore, terms defined in commonly used dictionaries can be interpreted to have a meaning consistent with what they mean in the context of the relevant art, and unless explicitly defined herein, they should not be interpreted as overly formal.

[0029] When an embodiment can be implemented differently, the order of certain steps may be different from that described. For example, two steps described as successive steps may be performed substantially simultaneously or may be performed in the reverse order from that described.

[0030] In the accompanying drawings, variations in the shapes shown may be expected due, for example, to manufacturing techniques and / or tolerances. Therefore, embodiments of the present invention should not be construed as limited to the specific shapes of regions shown herein and may include, for example, variations in shapes resulting from the manufacturing process. As used herein, the term "and / or" includes each and every combination of one or more of the referenced elements. Furthermore, the term "substrate" as used herein may refer to the substrate itself or a laminated structure including the substrate and a predetermined layer or film formed on its surface. Furthermore, as used herein, the term "surface of the substrate" may refer to the exposed surface of the substrate itself or the outer surface of a predetermined layer or film formed on the substrate.

[0031] (First embodiment) Fig. 1 is a perspective view showing a main part of a secondary battery 100 according to one embodiment of the present invention. Fig. 2 is a partial perspective view showing an enlarged view of a part of the secondary battery 100 of Fig. 1. Fig. 3 is a schematic perspective view showing the secondary battery 100 of Fig. 1 with a laminate sheet 130 removed.

[0032] In the following drawings, the secondary battery 100 is shown as being defined in a vertical coordinate system defined by a first direction along the X axis, a second direction along the Y axis, and a third direction along the Z axis, which are perpendicular to each other; however, the first direction, second direction, and third direction may be perpendicular to each other, and are not particularly limited thereto.

[0033] Referring to FIGS. 1 to 3, the secondary battery 100 includes a stacked electrode assembly 110, multifunctional terminal blocks (MTB) 120a and 120b, and a laminate sheet .

[0034] The stacked electrode assembly 110 may include a plurality of unit cells 111 stacked in a first direction (e.g., the X-axis direction). Each of the unit cells 111 may be formed by coating an electrode material on a metal foil that acts as a current collector.

[0035] Each unit battery 111 may have a thin plate-shaped body extending in a second direction (e.g., the Y-axis direction). Each unit battery 111 may be a positive electrode unit battery or a negative electrode unit battery. In some embodiments, the plurality of unit batteries 111 may be formed by stacking positive electrode unit batteries and negative electrode unit batteries alternately one by one. The positive electrode unit batteries and the negative electrode unit batteries may be separated from each other by a separator.

[0036] In some other embodiments, the plurality of unit batteries 111 may be formed by alternately stacking a plurality of positive electrode unit batteries and a plurality of negative electrode unit batteries. The plurality of positive electrode unit batteries and the plurality of negative electrode unit batteries may be separated from each other by a separator.

[0037] In some other embodiments, the plurality of unit batteries 111 may be formed by alternately stacking a plurality of positive electrode unit batteries and a plurality of negative electrode unit batteries. The plurality of positive electrode unit batteries and the plurality of negative electrode unit batteries may be separated from each other by a separator.

[0038] The stacked electrode assembly 110 may have electrode leads 116 at both ends in the second direction (e.g., the Y-axis direction). The electrode leads 116 may be electrically connected to electrode tabs of the plurality of unit batteries 111. One or more electrode tabs may be connected to one electrode lead 116. In some embodiments, two or more electrode tabs may be connected to one electrode lead 116.

[0039] The stacked electrode assembly 110 may include a first electrode stack 110a stacked in the first direction (e.g., the X-axis direction) while sharing one electrode lead 116, and a second electrode stack 110b stacked in the first direction (e.g., the X-axis direction) while sharing another electrode lead 116.

[0040] In some embodiments, the stacked electrode assembly 110 may have two electrode leads 116 on one side and two electrode leads 116 on the other side. In this case, the first electrode stack 110a included in the stacked electrode assembly 110 may have a first electrode lead 116a on one side and a second electrode lead 116b on the other side. Also, the second electrode stack 110b included in the stacked electrode assembly 110 may have a third electrode lead 116c on one side and a fourth electrode lead 116d on the other side. However, the present invention is not limited thereto.

[0041] A first MTB 120a may be provided at one end of the stacked electrode assembly 110 in the second direction (e.g., Y-axis direction), and a second MTB 120b may be provided at the other end. One of the first MTB 120a and the second MTB 120b may be electrically connected to the positive electrode side of the stacked electrode assembly 110, and the other may be electrically connected to the negative electrode side of the stacked electrode assembly 110. The second MTB 120b may have substantially the same configuration as the first MTB 120a, except for the polarity. The first MTB 120a will be described below, and those skilled in the art will be able to understand the configuration of the second MTB 120b from this description.

[0042] In some embodiments, the first MTB 120a may include an MTB housing 122, an electrode terminal portion 124 housed within the MTB housing 122, and a bus bar 125 (see FIG. 10) that electrically connects the electrode terminal portion 124 to the electrode lead 116.

[0043] The MTB housing 122 may include a relatively rigid material, such as a metal, and defines the exterior of the first MTB 120a. In some embodiments, the MTB housing 122 may be made of aluminum (Al), nickel (Ni), iron (Fe), cobalt (Co), chromium (Cr), manganese (Mn), or an alloy containing one or more of these.

[0044] The MTB housing 122 may include a through hole 122h exposing an electrode terminal portion 124, which will be described later. The through hole 122h may be provided in the MTB housing 122 such that the electrode terminal portion 124 is exposed in the second direction (e.g., the Y-axis direction). Therefore, the through hole 122h may be provided on a plane perpendicular to the second direction (e.g., the Y-axis direction) of the MTB housing 122. Furthermore, the through hole 122h may have an opening that is open in the longitudinal direction of the electrode assembly 110. The shape of the through hole 122h may be configured to match the outer edge shape of the portion of the electrode terminal portion 124 that is exposed to the outside.

[0045] In some embodiments, the electrode terminal portion 124 may have a flat surface exposed to the outside from the MTB housing 122. In some embodiments, the exposed surface may have a plane extending perpendicular to the second direction (e.g., the Y-axis direction). In some embodiments, the electrode terminal portion 124 may have a disk-shaped free surface exposed to the outside.

[0046] In some embodiments, an electrically insulating insulating gasket 129 may be provided between the electrode terminal portion 124 and the MTB housing 122 so that the electrode terminal portion 124 is electrically insulated from the MTB housing 122.

[0047] In some embodiments, the first MTB 120a may include a venting disk configured to rupture when the internal pressure of the secondary battery 100 increases excessively, thereby discharging gas that causes the excessively increased internal pressure. If the venting disk ruptures due to a thermal event occurring inside the secondary battery 100, the venting disk does not return to its original state. The venting disk may be any venting disk known in the art, and is not particularly limited.

[0048] In some embodiments, the MTB housing 122 may further include a fusion resin layer 122p on the side surface.

[0049] The fusion resin layer 122p is a layer of thermoplastic resin, and may contain, for example, one or more of polyolefin resin, polyester resin, polyamide resin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyacrylonitrile, polyurethane, polycarbonate, polyacetal, polyacrylate, and modified polyvinyl alcohol resin.

[0050] Examples of the polyolefin resin include polyethylene, polypropylene, poly(1-butene), poly(4-methyl-1-pentene), ethylene-propylene copolymer, copolymer of ethylene and an α-olefin having 4 or more carbon atoms, copolymer of polyolefin and maleic anhydride, ethylene-vinyl ester copolymer, ethylene-acrylic acid ester copolymer, and modified polyolefins obtained by graft-modifying these with unsaturated carboxylic acid or a derivative thereof, but the present invention is not limited thereto.

[0051] In some embodiments, the polyester resin includes polyethylene terephthalate, polybutylene terephthalate, or polyethylene naphthalate, although the invention is not limited thereto.

[0052] In some embodiments, the polyamide resin includes, but is not limited to, nylon 6, nylon 6·6, nylon 6 / 66 copolymer, nylon 11, nylon 12, or poly(m-xylene adipamide).

[0053] In some embodiments, the fusion resin layer 122p may be cast, or may be uniaxially or biaxially stretched or rolled.

[0054] In some embodiments, the fusion resin layer 122p may at least partially cover the side surface of the MTB housing 122. In some embodiments, the fusion resin layer 122p may extend from or near an inner end 122ie of the side surface of the MTB housing 122 toward an outer end 122oe of the side surface of the MTB housing 122. Here, the inner end 122ie refers to the end adjacent to the electrode lead 116. In some embodiments, the fusion resin layer 122p may surround the side surface of the MTB housing 122 while having a predetermined width between the inner end 122ie and the outer end 122oe. In some embodiments, the fusion resin layer 122p may extend along the side surface of the MTB housing 122 while having a predetermined width between the inner end 122ie and the outer end 122oe.

[0055] In some embodiments, the fusion resin layer 122p may have a constant width between the inner end 122ie and the outer end 122oe and may surround the side surface of the MTB housing 122. In some embodiments, the fusion resin layer 122p may have a constant width between the inner end 122ie and the outer end 122oe and may extend in a first direction (e.g., X-axis direction) and / or a third direction (e.g., Z-axis direction).

[0056] In some embodiments, the fusion resin layer 122p may extend along the side of the MTB housing 122 while having a constant width between the inner end 122ie and the outer end 122oe.

[0057] In some embodiments, the fusion resin layer 122p can cover the entire side surface of the MTB housing 122.

[0058] The fusion resin layer 122p may have a thickness of, for example, about 20 μm to about 400 μm. In some embodiments, the fusion resin layer 122p may have a thickness of about 20 μm to about 400 μm, about 30 μm to about 380 μm, about 40 μm to about 360 μm, about 50 μm to about 340 μm, about 60 μm to about 320 μm, about 70 μm to about 300 μm, about 80 μm to about 280 μm, about 90 μm to about 260 μm, about 100 μm to about 240 μm, about 110 μm to about 220 μm, about 120 μm to about 200 μm, about 130 μm to about 180 μm, about 140 μm to about 160 μm, or a range between any two of these values.

[0059] If the thickness of the fusion resin layer 122p is too thin, the mechanical strength may be insufficient, whereas if the thickness of the fusion resin layer 122p is too thick, it may be economically disadvantageous.

[0060] The fusion resin layer 122p may be fused to the laminate sheet 130. In some embodiments, the fusion resin layer 122p may extend from the end 130e of the laminate sheet 130. In some embodiments, the fusion resin layer 122p may be exposed from the edge portion 130e of the laminate sheet 130 and then extend toward the outer end 122oe.

[0061] In some embodiments, the first MTB 120a may further include a check valve 128. The check valve 128 may be configured to open to discharge internal gas when the internal pressure of the secondary battery 100 exceeds a predetermined pressure, and to close again when the internal pressure is relieved by discharging the gas. The check valve 128 does not have any parts that may burst due to the discharge of the gas, and may be restored to its original state after the internal gas is discharged.

[0062] The secondary battery 100 further includes an electrolyte. The electrolyte may be any electrolyte used for a typical lithium secondary battery, and is not particularly limited. In some embodiments, the electrolyte may be injected just before sealing the laminate sheet 130. In some embodiments, the electrolyte may be injected through an electrolyte injection port provided in the first MTB 120a after sealing the laminate sheet 130.

[0063] FIG. 4 is a side view showing the secondary battery 100 according to one embodiment of the present invention as viewed in a second direction (for example, the Y-axis direction).

[0064] 4, a fusion resin layer 122p may be provided between the MTB housing 122 and the laminate sheet 130 surrounding the MTB housing 122. The fusion resin layer 122p may have a locally increased thickness. In FIG. 4, the fusion resin layer 122p is shown to have a locally increased thickness on the upper surface of the MTB housing 122, but the present invention is not limited thereto.

[0065] In some embodiments, the fusion resin layer 122p may have a protrusion 122pp at a location where the thickness is locally increased. The protrusion 122pp may be located adjacent to the interleaving portion 130m where the laminate sheets 130 are interleaved. A gap may be formed between the interleaving portion 130m where the opposing laminate sheets 130 are interleaved and the MTB housing 122 due to insufficient bonding. This may result in problems such as electrolyte leakage or external moisture intrusion.

[0066] However, in the secondary battery 100 of the present invention, defects such as gaps occurring can be effectively prevented by disposing the protrusion 122pp between the interleaving portion 130m and the MTB housing 122, and therefore problems such as electrolyte leakage or intrusion of external moisture can be prevented.

[0067] In some embodiments, the interleaving portion 130m may be located substantially in the center of the secondary battery 100 in a first direction (e.g., the X-axis direction). In other embodiments, the interleaving portion 130m may be located adjacent to a corner of the MTB housing 122 shown in FIG.

[0068] In some embodiments, the fusion resin layer 122p may extend at least partially between the laminate sheets 130 of the interleaving section 130m. The portion of the fusion resin layer 122p extending between the laminate sheets 130 of the interleaving section 130m may be the protrusion 122pp.

[0069] The length d by which the protrusion 122pp extends between the laminate sheets 130 may be about 0.1 mm to about 2 mm. In some embodiments, the extended length d may be about 0.1 mm to about 2 mm, about 0.2 mm to about 1.9 mm, about 0.3 mm to about 1.8 mm, about 0.4 mm to about 1.7 mm, about 0.5 mm to about 1.6 mm, about 0.6 mm to about 1.5 mm, about 0.7 mm to about 1.4 mm, about 0.8 mm to about 1.3 mm, about 0.9 mm to about 1.2 mm, about 1 mm to about 1.1 mm, or a range between any two of these values.

[0070] If the extended length d of the protrusion 122pp is too small or too large, the effect of preventing defects such as blanks may be insufficient.

[0071] FIG. 5 is a partially enlarged view of the portion indicated by P in FIG.

[0072] 5, the fusion resin layer 122p may include an overlapping layer in which two polymer films 122pf1 and 122pf2 are overlapped adjacent to the interleaving portion 130m. In some embodiments, the overlapping polymer films 122pf1 and 122pf2 may be opposite ends of a single polymer film constituting the fusion resin layer 122p. That is, after the polymer film surrounds the MTB housing 122, both ends of the polymer film may overlap on one surface of the MTB housing 122.

[0073] In Figure 5, polymer films 122pf1 and 122pf2 are indicated by dotted lines, but in some cases, an interface between polymer films 122pf1 and 122pf2 may be visible, or an interface between polymer films 122pf1 and 122pf2 may not be visible due to fusion. In some embodiments, as shown in Figure 5, the location where fused resin layer 122p has a locally increased thickness (i.e., protruding portion 122pp) may be the result of the increased thickness being caused by the polymer film being coated more times than other locations. However, the present invention is not limited to this.

[0074] 6 is a side view showing a secondary battery 100 according to another embodiment of the present invention as viewed in a second direction (e.g., the Y-axis direction). In the embodiment described with reference to FIG. 4, the interleaving portion 130m is located at the center of the secondary battery 100 in the first direction (e.g., the X-axis direction), whereas in the embodiment of FIG. 6, the interleaving portion 130m is located adjacent to a corner of the MTB housing 122.

[0075] 6, the interleaving portion 130m can be located adjacent to any corner of the MTB housing 122. In some embodiments, the interleaving portion 130m can be located adjacent to one of two of the four corners of the MTB housing 122 that are closest to the check valve 128. In other embodiments, the interleaving portion 130m can be located adjacent to one of two of the four corners of the MTB housing 122 that are farthest from the check valve 128.

[0076] The position of the protrusion 122pp may be substantially the same as the position of the interleaving portion 130m. Therefore, the protrusion 122pp may be located adjacent to any corner of the MTB housing 122. In some embodiments, the protrusion 122pp may be located adjacent to one of two of the four corners of the MTB housing 122 that are closest to the check valve 128. In other embodiments, the protrusion 122pp may be located adjacent to one of two of the four corners of the MTB housing 122 that are farthest from the check valve 128.

[0077] Fig. 7 is a partially exploded perspective view showing a joining method of the laminate sheet 130 of the secondary battery 100 according to one embodiment of the present invention. Fig. 8 is a partial cross-sectional view of the laminate sheet 130 according to one embodiment of the present invention.

[0078] 7 and 8, the laminate sheet 130 may be configured to wrap around the side surfaces of the stacked electrode assembly 110. In some embodiments, the laminate sheet 130 may be attached to the side surfaces of the MTBs 120a and 120b so as to at least partially cover the side surfaces of the MTBs 120a and 120b. In some embodiments, the pair of parallel edge portions 130e of the laminate sheet 130 may cover the entire side surfaces of the MTBs 120a and 120b parallel to the second direction (e.g., the Y-axis direction). In other embodiments, the pair of parallel edge portions 130e of the laminate sheet 130 may cover only a portion of the side surfaces of the MTBs 120a and 120b parallel to the second direction (e.g., the Y-axis direction).

[0079] The laminate sheet 130 may include a flexible metal layer 134, an inner resin layer 132 provided on one side of the metal layer 134, and an outer resin layer 136 provided on the other side of the metal layer 134.

[0080] The metal layer 134 maintains an appropriate thickness and prevents water vapor, oxygen, and other gases from penetrating from the outside to the inside, thereby preventing leakage of the electrolyte. In some embodiments, the metal layer 134 may include, but is not limited to, any one or more selected from iron (Fe), carbon (C), chromium (Cr), manganese (Mn), nickel (Ni), aluminum (Al), and alloys thereof. When the metal layer 134 is made of a material containing iron, it has high mechanical strength, and when it is made of aluminum, it has good flexibility, so aluminum metal foil is typically used.

[0081] The metal layer 134 can be relatively easily deformed by an external force and can be configured to have an appropriate thickness and mechanical strength so that cracks or holes do not occur even when repeatedly deformed.

[0082] In some embodiments, the metal layer 134 can have a thickness of about 20 micrometers (μm) to about 100 μm. In some embodiments, the thickness of the metal layer 134 can be about 20 μm to about 100 μm, about 25 μm to about 95 μm, about 30 μm to about 90 μm, about 35 μm to about 85 μm, about 40 μm to about 80 μm, about 45 μm to about 75 μm, about 50 μm to about 70 μm, about 55 μm to about 60 μm, or a range between any two of these values.

[0083] The inner resin layer 132 provided on one side of the metal layer 134 may include a thermal adhesive layer. In some embodiments, the inner resin layer 132 may include a polyolefin-based material capable of performing a sealing function by fusion. In some embodiments, the inner resin layer 132 may include modified propylene such as cast polypropylene (CPP) or a polypropylene-butylene-ethylene terpolymer.

[0084] The inner resin layer 132 may be formed by coating or laminating one side of the metal layer 134 .

[0085] The outer resin layer 136 provided on the other side of the metal layer 134 may act as a base substrate and a protective layer for forming the laminate sheet 130. The outer resin layer 136 may include an insulating material such as polyethylene terephthalate (PET) or nylon.

[0086] In some embodiments, the inner resin layer 132 and the outer resin layer 136 may each have a thickness of about 10 micrometers (μm) to about 50 μm. In some embodiments, the thickness of the inner resin layer 132 and the outer resin layer 136 may be about 10 μm to about 50 μm, about 12 μm to about 48 μm, about 15 μm to about 45 μm, about 17 μm to about 43 μm, about 20 μm to about 40 μm, about 22 μm to about 38 μm, about 25 μm to about 35 μm, about 27 μm to about 33 μm, or a range between any two of these values.

[0087] In some embodiments, an adhesive resin layer may be further provided between the inner resin layer 132 and the metal layer 134 and / or between the outer resin layer 136 and the metal layer 134. The adhesive resin layer may be provided to facilitate smooth adhesion between different materials. The adhesive resin layer may be formed as a single layer or multiple layers. In some embodiments, the adhesive resin layer may include a polyolefin-based resin, a polyurethane-based resin, an epoxy-based resin, or a mixture thereof.

[0088] In some embodiments, the inner resin layer 132 may be fused to the fusion resin layers 122p provided on the sides of the MTBs 120a and 120b at both ends in the second direction (e.g., the Y-axis direction). The inner resin layer 132 may be fused to the fusion resin layers 122p while surrounding the sides of the MTBs 120a and 120b, thereby sealing the stacked electrode assembly 110 within the laminate sheet 130.

[0089] The inner resin layer 132 facing the first MTB 120a may be melted by heating and cooled while in contact with the fusion resin layer 122p on a side surface of the first MTB 120a, thereby being fused to the side surface, thereby forming a first sealing portion 130m1. The inner resin layer 132 facing the second MTB 120b may be melted by heating and cooled while in contact with the fusion resin layer 122p on a side surface of the second MTB 120b, thereby being fused to the side surface, thereby forming a second sealing portion 130m2.

[0090] The end portions 130t of the laminate sheet 130 are fused to each other to form a joining portion 130m (see FIG. 1) after surrounding the sides of the MTBs 120a and 120b and the stacked electrode assembly 110. Specifically, the laminate sheet 130 is adhered to each other at the joining portion 130m so that the inner resin layers 132 face each other, and then the facing inner resin layers 132 may be fused to each other.

[0091] The interleaving portion 130m may be located on any one side of the stacked electrode assembly 110. In some embodiments, the interleaving portion 130m may be located in a third direction (e.g., Z-axis direction) of the stacked electrode assembly 110 after surrounding the stacked electrode assembly 110.

[0092] The fusion resin layer 122p may include an extension 122pe extending from the edge 130e of the laminate sheet 130 along the side of the MTB housing 122. The extension 122pe may extend a predetermined length from the edge 130e of the laminate sheet 130 toward the outer end 122oe of the MTB housing 122.

[0093] FIG. 9 is a schematic diagram showing a main part of the extension 122pe exposed from the edge 130e of the laminate sheet 130. As shown in FIG.

[0094] 9, the thickness d2 of the fusion resin layer 122p at the position where the extension portion 122pe has a locally increased thickness is greater than the thickness d1 of the fusion resin layer 122p at other positions of the extension portion 122pe. For example, the thickness d2 may be about 1.8 to 2.2 times the thickness d1.

[0095] Because the extension 122pe is an exposed portion of the laminate sheet 130, it is not or only minimally affected by heat when the laminate sheet 130 is fused to the MTB housing 122 with the fusion resin layer 122p interposed therebetween. Therefore, in the extension 122pe, an overlapping layer of polymer film may remain at a position with locally increased thickness. In some cases, the overlapping layer of polymer film may not be observed to have melted and overlapped in the fusion resin layer 122p fused between the laminate sheet 130 and the MTB housing 122.

[0096] FIG. 10 is a cross-sectional view showing a main part of a cross section of the first MTB 120a and the laminate sheet 130 according to one embodiment of the present invention taken along line XX' in FIG.

[0097] 10 , a bus bar 125 may be provided to make surface contact with the electrode terminal portion 124. The bus bar 125 may be made of a metal material having low electrical resistance. In some embodiments, the bus bar 125 may be made of copper (Cu), nickel (Ni), aluminum (Al), iron (Fe), cobalt (Co), platinum (Pt), molybdenum (Mo), tin (Sn), palladium (Pd), or an alloy containing one or more of these.

[0098] The bus bar 125 may be configured to make surface contact with the electrode lead 116 of the stacked electrode assembly 110. In some embodiments, the bus bar 125 may be coupled to the electrode lead 116 by welding. In some embodiments, the bus bar 125 may be coupled to the electrode lead 116 by fasteners, for example, rivets.

[0099] In some embodiments, the bus bar 125 may include a planar center portion 125c extending horizontally in the first direction (e.g., the X-axis direction) and edge portions 125e bent and extending from the center portion 125c. The center portion 125c may be configured to form a substantially U-shaped cross section together with the edge portions 125e and may extend in the third direction (e.g., the Z-axis direction). In some embodiments, the edge portions 125e may have a plane extending perpendicular to the first direction (e.g., the X-axis direction).

[0100] The center portion 125c of the bus bar 125 may be in surface contact with the electrode terminal portion 124. The edge portion 125e of the bus bar 125 may be in surface contact with the electrode lead 116.

[0101] In some embodiments, the electrode lead 116 may include a pre-bended portion that is bent at a portion that does not contact the bus bar 125. The pre-bended portion may prevent stress from concentrating at a specific portion of the electrode lead 116 due to an external force applied to the stacked electrode assembly 110, thereby improving safety.

[0102] The laminate sheet 130 may be fused to the adhesive resin layer 122p. More specifically, the inner resin layer 132 of the laminate sheet 130 may be fused to the adhesive resin layer 122p.

[0103] In Figure 10, an interface is shown to exist between the internal resin layer 132 and the fused resin layer 122p, but this is for ease of understanding, and in reality, an interface may not be visible between the internal resin layer 132 and the fused resin layer 122p.

[0104] As described above, the extension 122pe of the fusion resin layer 122p can extend somewhat from the edge 130e of the laminate sheet 130 toward the outer end 122oe of the side surface of the MTB housing 122.

[0105] (Second embodiment) FIG. 11 is a partially exploded perspective view showing a joining method of a laminate sheet 130 of a secondary battery 100 according to another embodiment of the present invention.

[0106] 11, the fusion resin layer 122p may have a protrusion 122pp having a locally increased thickness. In some embodiments, the protrusion 122pp may protrude in a third direction (e.g., the Z-axis direction) with a length d as described with reference to FIG.

[0107] In some embodiments, the adhesive resin layer 122p may be a polymer ring provided on the edge of the MTB housing 122. The material of the polymer ring may be the same as that of the adhesive resin layer 122p described above with reference to Figures 1 to 3, and therefore further description will be omitted here.

[0108] The method for forming the protrusion 122pp provided on the fusion resin layer 122p will be described in more detail later. The protrusion 122pp may be, for example, a portion of the polymer ring to which tension is applied when the polymer ring is fused to form the fusion resin layer 122p on the edge of the MTB housing 122.

[0109] (Third embodiment) Fig. 12 is a flowchart showing a method for manufacturing the secondary battery 100 according to one embodiment of the present invention. Figs. 13 to 19 are perspective views or side views showing a method for manufacturing the secondary battery 100 according to one embodiment of the present invention.

[0110] 12 and 13, MTBs 120a and 120b are coupled to both ends of a stacked electrode assembly 110 including a plurality of unit batteries 111 stacked in a first direction (e.g., the X-axis direction) (S110).

[0111] The stacked electrode assembly 110 may have electrode leads at both ends in the second direction (for example, the Y-axis direction). This has been described with reference to FIG. 3, so a detailed description thereof will be omitted here.

[0112] In some embodiments, the electrode leads may be welded to the bus bars of the MTBs 120a, 120b, thereby connecting the MTBs 120a, 120b to the stacked electrode assembly 110. The welding method is not particularly limited, and any suitable method known to those of ordinary skill in the art may be used.

[0113] Referring to FIGS. 12 and 14, a fusion resin layer 122p may be formed on the edge of the MTB housing 122 of the MTBs 120a and 120b (S120).

[0114] In some embodiments, the method of forming the fusion resin layer 122p can be as described with reference to Figures 5 and 9, in which a polymer film is wrapped around the edge of the MTB housing 122 and partially overlaps the side of the MTB housing 122. The overlapping portion of the polymer film has a locally increased thickness, and a laminate sheet can be laminated in this portion, as described below.

[0115] In some embodiments, a method for forming the fusion resin layer 122p can be to provide a polymer ring on the edge of the MTB housing 122 and use it to form the protrusions. Figures 15-17 are diagrams illustrating one embodiment of a method for forming the fusion resin layer 122p.

[0116] 15, a polymer ring 122pr can be provided on the edge of the MTB housing 122. The inner length of the polymer ring 122pr is longer than the length of the outer circumferential surface of the MTB housing 122. Therefore, the polymer ring 122pr can be easily provided on the edge of the MTB housing 122.

[0117] Referring to Fig. 16, the polymer ring 122pr can be adhered from one side of the MTB housing 122. Fig. 16 shows the polymer ring 122pr adhering from the lower end of the MTB housing 122 to the side of the MTB housing 122. However, the present invention is not limited to this. In some embodiments, the polymer ring 122pr can be fused to the surface of the MTB housing 122 while adhering to it.

[0118] 17, a remaining length of the polymer ring 122pr remains on a specific portion of the MTB housing 122. This is because the inner length of the polymer ring 122pr is longer than the length of the outer circumferential surface of the MTB housing 122. The remaining length portions of the polymer ring 122pr can be fused together with the inner surfaces of the polymer rings 122pr facing each other.

[0119] The portion where the remaining length portions of the polymer ring 122pr are fused together forms a locally increased thickness of the fused resin layer 122p. Laminating resin 130 may be applied to the portion where the remaining length portions of the polymer ring 122pr are fused together. In some embodiments, tension may be applied to the polymer ring 122pr when the polymer ring 122pr is brought into close contact with the surface of the MTB housing 122. In some embodiments, the position where tension is applied to the polymer ring 122pr may be the remaining length portion of the polymer ring 122pr.

[0120] In some embodiments, the remaining length of the polymer ring 122pr may be positioned in the center of the secondary battery 100 in the first direction (e.g., the X-axis direction). That is, the remaining length of the polymer ring 122pr may be positioned in the center of the MTB housing 122 in the first direction (e.g., the X-axis direction).

[0121] FIG. 18 is a diagram showing another embodiment of the method for forming the fusion resin layer 122p, and shows the results performed subsequent to FIG.

[0122] 18, the remaining length of the polymer ring 122pr can be positioned adjacent to a corner of the MTB housing 122. A person of ordinary skill in the art can position the remaining length of the polymer ring 122pr as described with reference to FIG.

[0123] 12 to 14, the MTB 120 is bonded to both end portions of the stacked electrode assembly 110, and then the fusion resin layer 122p is formed on the edge of the MTB housing 122. However, the present invention is not limited to this. In some other embodiments, the MTB 120 may be bonded to both end portions of the stacked electrode assembly 110 after the fusion resin layer 122p is formed on the edge of the MTB housing 122.

[0124] Referring to FIGS. 12 and 19, the laminate sheet is bonded to the adhesive resin layer 122p so as to wrap the side surface of the stacked electrode assembly 110 (S130).

[0125] The laminate sheet 130 may have a pair of substantially parallel edge portions 130e fused to the outer side surface of the MTB 120. Meanwhile, a pair of substantially parallel end portions 130t connecting the pair of edge portions 130e of the laminate sheet 130 may have portions that are not fused to each other, and a portion of the stacked electrode assembly 110 may be exposed between the pair of end portions 130t.

[0126] The interleaving portion 130m to which the pair of end portions 130t are fused can be positioned adjacent to the locally thickened portion of the fusion resin layer 122p described above.

[0127] Thereafter, an electrolyte may be supplied to the stacked electrode assembly 110 through the unfused portions of the pair of end portions 130t (S140).

[0128] In some embodiments, the step of supplying the electrolyte may be performed after attaching the laminate sheet 130 to the MTB 120. In some embodiments, the step of supplying the electrolyte may be performed after sealing the laminate sheet. In this case, at least one of the MTBs 120 may include an electrolyte inlet.

[0129] The electrolyte may be any of the common electrolytes used for lithium secondary batteries, and is not particularly limited.

[0130] When an electrolyte is supplied to the stacked electrode assembly 110 through the unfused portions of the pair of end portions 130t, the laminate sheet 130 may then be sealed (S150). Specifically, the laminate sheet 130 may be sealed by joining the end portions 130t of the laminate sheet 130 to each other. In some embodiments, the end portions 130t may be laminated by bringing the inner resin layers 132 of the end portions 130t into face-to-face contact with each other and then applying heat. In other embodiments, the end portions 130t may be laminated by bringing the inner resin layer 132 of one end portion 130t into face-to-face contact with the outer resin layer 136 of the other end portion 130t and then applying heat.

[0131] (Fourth embodiment) FIG. 20 is a schematic perspective view of a battery pack 1 according to one embodiment of the present invention, FIG. 21 is an exploded perspective view showing the configuration of the battery pack 1 of FIG. 20, and FIG. 22 is a perspective view showing the battery cell 100 of FIG. 21 seated in a pack housing.

[0132] 20 to 22, a battery pack 1 according to one embodiment of the present invention includes a plurality of battery cells 100, an electrical component assembly 500, a pack housing 300, and a pack cover 600. In the battery pack 1 shown in FIG.

[0133] The battery cells 100 may be stacked in a first direction (e.g., the X-axis direction), and the cooling pads 200 may be interposed between the battery cells. In some embodiments, the stack of the battery cells 100 and the cooling pads 200 may be directly housed in the pack housing 300 without being housed in another frame. However, those skilled in the art will understand that various modifications are possible regarding the method of housing the battery cells 100.

[0134] For example, a stack of the battery cells 100 and the cooling pads 200 may be housed in a module frame to form a battery module, and the battery module may be housed in the pack housing 300. The module frame may be configured in the form of a rectangular box surrounding the outer periphery of the stack of the battery cells 100 and the cooling pads 200 so that the stack of the battery cells 100 and the cooling pads 200 can be held therein. The module frame may be made of a metal material having high mechanical rigidity so as to sufficiently protect the battery cells 100 from swelling of the battery cells 100 and external impacts.

[0135] The electrical equipment assembly 500 may include a relay device, a current sensor, a fuse, a BMS (Battery Management System), an MSD (Manual Service Disconnector), etc. The relay device is a switching component that selectively opens and closes a charge / discharge path through which current flows, and can cut off the flow of charge / discharge current when an abnormality occurs in the battery pack 1. The BMS refers to a battery management device that generally controls the charge / discharge operation of the battery cells 100, and can be said to be a component that is usually included in the battery pack 1. The MSD is a system for selectively cutting off the power supply of the high-voltage battery in a physical manner, and cuts off the power supply by separating the service plug when necessary.

[0136] The electrical equipment assembly 500 can be packaged together with the battery cell 100 by the pack housing 300 and the pack cover 600 so as not to be exposed to the outside.

[0137] The pack housing 300 can be said to be a structure that provides a space in which the battery cells 100 and the electrical equipment assembly 500 can be housed, and is provided with brackets 332 and mounting structures 343 and 353 so that it can be connected to the vehicle body.

[0138] The pack housing 300 provides mechanical support to the battery module 100 and the electrical component assembly 500 and protects them from external impacts, and therefore may be made of a highly rigid metal material.

[0139] The pack housing 300 according to the present embodiment may include a lower frame 310 in the form of a wide plate on which the battery cells 100 can be mounted, and a front frame 320, a rear frame 330, a right side frame 340, and a left side frame 350 that are vertically coupled to the edges of the lower frame 310 to form walls. The pack housing 300 may further include a center beam 370 and a cross beam 360 to define a space in which the battery cells 100 can be mounted. One end of the center beam 370 may be coupled to the front frame 320 and the other end may be coupled to the rear frame 330. In some embodiments, the cross beam 360 may have one end coupled to the center beam 370 and the other end coupled to the right side frame 340 or the left side frame 350. In some embodiments, the cross beam 360 may extend across the center beam 370 and have one end coupled to the right side frame 340 and the other end coupled to the left side frame 350.

[0140] In some embodiments, the lower frame 310, the front frame 320, the rear frame 330, the right side frame 340, the left side frame 350, and the cross beam 360 may each be an aluminum extrusion structure, and the pack housing 300 may be made by welding and / or bolting the frames together.

[0141] For example, by extruding aluminum to create the frame and welding it together to form the pack housing 300, the weight of the pack housing 300 can be reduced and the mechanical rigidity can be made to be more reliable than required.

[0142] In some embodiments, a heat sink may be further provided within the pack housing 300. The heat sink may be provided in the form of a plate-like body with a flow path therein so as to absorb and discharge heat from another object through thermal contact. In some embodiments, the lower frame 310 may include an inlet port 410a through which cooling water can flow, an outlet port 410b through which the cooling water can be discharged, and a cooling water channel through which the cooling water can flow.

[0143] The battery cells 100 may be electrically connected by inter-bus bars 510, 520, and 530. The inter-bus bars may include a first inter-bus bar 510 that electrically connects the battery modules 100 arranged in a 2×2 configuration along a first direction (e.g., X-axis direction) and a second direction (e.g., Y-axis direction). In some embodiments, the first inter-bus bar 510 may be provided at a position where the center beam 370 and the cross beams 360 intersect.

[0144] In addition, the inter-bus bar may include a second inter-bus bar 520 that electrically connects the electrically connected battery cells 100 to an external load or a charging system. The second inter-bus bar 520 does not need to be directly connected to the external load or charging system, but may be connected to the external load or charging system via the electrical component assembly 500.

[0145] The battery module 100 may include a first group of battery cells 100A located on one side of a center beam 370 and a second group of battery cells 100B located on the other side of the center beam 370. The inter-bus bars may include a third inter-bus bar 530 electrically connecting the first group of battery cells 100A and the second group of battery cells 100B.

[0146] Although the embodiments of the present invention have been described in detail above, those skilled in the art can implement the present invention in various modifications without departing from the spirit and scope of the present invention as defined in the appended claims. Therefore, future changes to the embodiments of the present invention will not depart from the technology of the present invention. [Explanation of symbols]

[0147] 1: Battery pack 100: Secondary battery 110: Stacked electrode assembly 111: Unit battery 116: Electrode lead 120, 120a, 120b:MTB 122:MTB housing 122h: Through hole 122p: Fusion resin layer 122pe: Extension part 122pp:Protrusion 124: Electrode terminal part 125: Busbar 128: Check valve 130: Laminated sheet 130e: Edge 130m: interleaf section 130t: End part 132: Internal resin layer 134: Metal layer 136: Outer resin layer

Claims

1. a stacked electrode assembly in which a plurality of unit cells are stacked in a first direction and have electrode leads on both side ends in a second direction perpendicular to the first direction; a multifunctional terminal block (MTB) provided at each end of the stacked electrode assembly; a laminate sheet that wraps the side surfaces of the stacked electrode assembly; wherein the MTB includes a fusion resin layer having a locally increased thickness on a side surface.

2. 2. The secondary battery according to claim 1, wherein the laminate sheet has an interleaving portion at a position where the fusion resin layer has a locally increased thickness.

3. the fusion resin layer is a polymer film, The secondary battery according to claim 2 , wherein the thickness of the fusion resin layer is locally increased at a location where the thickness is increased because the polymer film is coated more frequently than at other locations.

4. The secondary battery according to claim 2 , wherein the fusion resin layer includes an extension extending from an edge of the laminate sheet along a side surface of the MTB.

5. 5. The secondary battery according to claim 4, wherein the thickness of the fusion resin layer at the position having the locally increased thickness in the extension portion is about 1.8 to about 2.2 times the thickness of the fusion resin layer at other positions in the extension portion.

6. The secondary battery according to claim 2 , wherein the interleaving portion is positioned substantially at a center portion of the secondary battery in the first direction.

7. the fusion resin layer is a polymer ring fused to the edge of the MTB housing of the MTB; 3. The secondary battery according to claim 2, wherein the location where the fusion resin layer has a locally increased thickness is a portion where tension is applied to the polymer ring when the polymer ring is fused to the edge of the MTB housing.

8. The secondary battery according to claim 7 , wherein the fusion resin layer extends at least partially between the interleaving portions.

9. 9. The secondary battery according to claim 8, wherein the length of the fusion resin layer extending between the interleaving portions is about 0.1 mm to about 2 mm.

10. coupling a multifunctional terminal block (MTB) to both ends of a stacked electrode assembly including a plurality of unit cells stacked in a first direction and having electrode leads at both ends in a second direction perpendicular to the first direction; forming a fusion resin layer on an edge of the MTB housing of the MTB; bonding a laminate sheet to the adhesive resin layer so as to enclose a side surface of the stacked electrode assembly; Including, A method for manufacturing a secondary battery, wherein the fusion resin layer has a locally increased thickness, and the laminate sheet has an interleaving section at a position where the fusion resin layer has a locally increased thickness.

11. The method for manufacturing a secondary battery according to claim 10 , wherein the step of forming the fusion resin layer includes the step of locally forming an overlapping layer of a polymer film.

12. The method for manufacturing a secondary battery according to claim 11 , wherein the polymer film is configured to surround and then locally overlap the side surface of the MTB housing.

13. The step of forming the fusion resin layer includes: providing a polymer ring on a rim of the MTB housing, the polymer ring having an inner length greater than a length of an outer periphery of the MTB housing; fusing the polymer ring onto a side of the MTB housing from one side of the MTB housing; fusing the remaining lengths of the polymer rings together; The method for producing a secondary battery according to claim 10 , comprising:

14. 14. The method for manufacturing a secondary battery according to claim 13, wherein in the step of fusing the remaining lengths of the polymer rings to each other, the positions at which the polymer rings are fused to each other substantially coincide with the positions at which the laminate sheets have interleaving portions.

15. Within the MTB housing: an electrode terminal portion electrically connected to an electrode lead of the stacked electrode assembly; a bus bar electrically connecting the electrode lead of the stacked electrode assembly to the electrode terminal portion; is provided, The laminate sheet is a flexible metal layer; an inner resin layer provided on one side of the metal layer; an outer resin layer provided on the other side of the metal layer; Including, The method of manufacturing a secondary battery according to claim 10 , wherein the inner resin layer comprises cast polypropylene (CPP).

Images