Secondary battery

Abstract

Provided is a secondary battery comprising: a stack-type electrode assembly having a plurality of unit batteries stacked in a first direction, and electrode leads formed at respective ends thereof in a second direction perpendicular to the first direction; multifunctional terminal blocks (MTBs) provided at the respective ends of the stack-type electrode assembly; and a laminate sheet surrounding a side surface of the stack-type electrode assembly, wherein the MTBs comprise a fusion resin layer on a side surface thereof.

Description

secondary batteries

[0001] The present invention relates to a secondary battery, and more particularly, to a secondary battery having improved product durability and safety by improving adhesion between a flexible laminate sheet and an MTB.

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0084788, filed June 30, 2023, the entire disclosure of which is incorporated herein by reference.

[0003] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. They are widely used as a power source for various wireless devices, including handsets, laptops, and cordless vacuum cleaners. Recently, improved energy density and economies of scale have dramatically reduced the per-unit manufacturing cost of secondary batteries. Furthermore, as the range of battery electric vehicles (BEVs) has increased to match that of fuel-powered vehicles, the primary use of secondary batteries is shifting from mobile devices to mobility.

[0004] Meanwhile, demand for large-capacity battery packs for electric vehicles and other applications is increasing. Large-capacity battery packs installed in automobiles are expected to increase capacity and enhance safety.

[0005] The technical problem to be achieved by the present invention is to provide a secondary battery having improved product durability and safety by improving the adhesion between a flexible laminate sheet and an MTB.

[0006] The present invention provides a secondary battery comprising: a stacked electrode assembly in which a plurality of unit cells are stacked in a first direction and have electrode leads at both ends in a second direction perpendicular to the first direction; a multifunctional terminal block (MTB) provided at both ends of the stacked electrode assembly; and a laminate sheet wrapping a side surface of the stacked electrode assembly, wherein the MTB includes a fusion resin layer on the side surface.

[0007] In some embodiments, the laminate sheet may at least partially overlap a side surface of the MTB, and the laminate sheet may be fused with the fusion resin layer.

[0008] In some embodiments, 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, wherein the inner resin layer may include cast polypropylene (CPP).

[0009] In some embodiments, the fusion resin layer may be fused with the inner resin layer.

[0010] In some embodiments, the fusion resin layer may include a polypropylene resin.

[0011] In some embodiments, the fusion resin layer may include an extension extending from an end of the laminate sheet along a side surface of the MTB.

[0012] In some embodiments, the side of the MTB may be at least partially roughened.

[0013] In some embodiments, the fusion resin layer may cover the roughened portion of the MTB.

[0014] In some embodiments, the side of the MTB may be roughened by surface etching.

[0015] In some embodiments, the MTB may include an electrode terminal electrically connected to an electrode lead of the stacked electrode assembly; and a rupture disk that ruptures to discharge gas when internal pressure increases.

[0016] In some embodiments, the MTB may further include a bus bar electrically connecting the electrode leads of the stacked electrode assembly and the electrode terminal portion.

[0017] Another aspect of the present invention provides a secondary battery comprising: a stacked electrode assembly in which a plurality of unit cells are stacked in a first direction, extending in a second direction perpendicular to the first direction and having electrode leads at ends; a multifunctional terminal block (MTB) coupled to the electrode leads of the stacked electrode assembly and including an electrode terminal portion and a bus bar; and a laminate sheet wrapping the stacked electrode assembly together with the MTB, wherein the side surface of the MTB is roughened.

[0018] In some embodiments, the roughened side of the MTB may be at least partially covered by a fused resin layer.

[0019] In some embodiments, 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, wherein the outer resin layer may be fused with the fusion resin layer.

[0020] In some embodiments, the fusion resin layer may include an extension extending from an end of the laminate sheet along a side surface of the MTB.

[0021] The secondary battery according to embodiments of the present invention has the effect of improving product durability and safety by improving the adhesion between the flexible laminate sheet and the MTB.

[0022] The effects that can be obtained from the exemplary embodiments of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by those skilled in the art to which the exemplary embodiments of the present disclosure pertain from the following description. In other words, unintended effects resulting from practicing the exemplary embodiments of the present disclosure can also be derived by those skilled in the art from the exemplary embodiments of the present disclosure.

[0023] Figure 1 is a perspective view showing the main parts of a secondary battery according to one embodiment of the present invention.

[0024] Fig. 2 is a partial perspective view showing an enlarged portion of a part of the secondary battery of Fig. 1.

[0025] Figure 3 is a schematic perspective view showing the appearance of the laminate sheet removed from the secondary battery of Figure 1.

[0026] Figure 4 is a schematic diagram showing a cross-section of the first MTB cut along a plane perpendicular to the third direction and passing through the electrode terminal portion.

[0027] FIG. 5 is a partially exploded perspective view showing a method of bonding laminate sheets of a secondary battery according to one embodiment of the present invention.

[0028] Figure 6 is a partial cross-sectional view of a laminate sheet according to one embodiment of the present invention.

[0029] FIG. 7 is a cross-sectional view showing a main portion of a cross-section of a first MTB and a laminate sheet according to one embodiment of the present invention taken along line VII-VII' of FIG. 5.

[0030] FIG. 8 is a cross-sectional view showing a main portion of a first MTB and laminate sheet according to another embodiment of the present invention taken along line VII-VII' of FIG. 5.

[0031] Figures 9 to 11 are schematic diagrams showing the main portion of the outer surface of the first MTB according to embodiments of the present invention.

[0032] Figure 12a is a perspective view showing a main part of a secondary battery according to one embodiment of the present invention.

[0033] Figure 12b is a partial perspective view showing an enlarged portion of a portion of the secondary battery of Figure 12a.

[0034] Figure 13 is a side view of a secondary battery according to another embodiment of the present invention.

[0035] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the embodiments of the present invention may be modified in various different forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. It is preferable to interpret that the embodiments of the present invention are provided to more completely explain the present invention to those of ordinary skill in the art. Like numbers refer to like elements throughout. Furthermore, various elements and areas in the drawings are schematically drawn. Therefore, the present invention is not limited by the relative sizes or spacings depicted in the accompanying drawings.

[0036] While terms like "first" and "second" may be used to describe various components, these components are not limited by these terms. These terms are used solely to distinguish one component from another. For example, a first component could be referred to as a "second component," and vice versa, without departing from the scope of the present invention.

[0037] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the inventive concept. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the expressions "comprises" or "has" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, numbers, operations, components, parts, or combinations thereof.

[0038] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Furthermore, it is to be understood that commonly used terms, such as those defined in dictionaries, should be interpreted to have a meaning consistent with their meaning within the relevant technical context, and should not be interpreted in an overly formal sense unless explicitly defined herein.

[0039] In some embodiments, where implementations are otherwise feasible, specific process sequences may be performed in a different order than described. For example, two processes described in succession may be performed substantially simultaneously, or in a reverse order from the described order.

[0040] In the accompanying drawings, variations in the shapes depicted may be expected, for example, depending on manufacturing techniques and / or tolerances. Therefore, embodiments of the present invention should not be construed as being limited to the specific shapes of the regions depicted herein, but should include, for example, changes in shapes resulting from the manufacturing process. All terms "and / or" used herein include each and every combination of one or more of the mentioned components. In addition, the term "substrate" used herein may mean the substrate itself, or a laminated structure including the substrate and a predetermined layer or film formed on the surface thereof. In addition, the "surface of the substrate" in this specification may mean the exposed surface of the substrate itself, or the outer surface of a predetermined layer or film formed on the substrate.

[0041]

[0042] (Example 1)

[0043] Fig. 1 is a perspective view showing the 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 portion 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 the laminate sheet (130) removed.

[0044] In the drawings below, the secondary battery (100) is illustrated 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, but the first direction, the second direction, and the third direction are not particularly limited as long as they are relatively perpendicular to each other.

[0045] Referring to FIGS. 1 to 3, the secondary battery (100) includes a stacked electrode assembly (110), a multifunctional terminal block (MTB) (120a, 120b), and a laminate sheet (130).

[0046] The stacked electrode assembly (110) may include a plurality of unit cells (111) stacked in a first direction (e.g., X-axis direction). Each of the unit cells (111) may have an electrode material applied on a metal foil that acts as a current collector.

[0047] Each of the unit cells (111) may have a thin plate-shaped body extending in a second direction (e.g., the Y-axis direction). Each of the unit cells (111) may be a positive electrode unit cell or a negative electrode unit cell. In some embodiments, the plurality of unit cells (111) may be formed by alternately stacking positive electrode unit cells and negative electrode unit cells one by one. The positive electrode unit cell and the negative electrode unit cell may be separated from each other by a separator.

[0048] In some other embodiments, the plurality of unit batteries (111) may be formed by alternately stacking a plurality of positive unit batteries and a plurality of negative unit batteries. The plurality of positive unit batteries and the plurality of negative unit batteries may be separated from each other by a separator.

[0049] The stacked electrode assembly (110) may have electrode leads (116) at both ends in the second direction (e.g., Y-axis direction). The electrode leads (116) may be electrically connected to electrode tabs of the plurality of unit cells (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).

[0050] 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, half of the plurality of unit cells (111) included in the stacked electrode assembly (110) may be coupled to the first electrode lead on one side and coupled to the second electrode lead on the other side. In addition, the remaining half of the plurality of unit cells (111) included in the stacked electrode assembly (110) may be coupled to the third electrode lead on one side and coupled to the fourth electrode lead on the other side. However, the present invention is not limited thereto.

[0051] In some embodiments, the stacked electrode assembly (110) may have one or more electrode leads on one side. In some embodiments, the stacked electrode assembly (110) may have one or more electrode leads on the other side.

[0052] 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. Hereinafter, the first MTB (120a) will be described, but a person skilled in the art will be able to understand the configuration of the second MTB (120b) therefrom.

[0053] In some embodiments, the first MTB (120a) may include an MTB housing (122), an electrode terminal portion (124) accommodated within the MTB housing (122), and a bus bar (125) (see FIG. 4) electrically connecting the electrode terminal portion (124) and the electrode lead (116).

[0054] The above MTB housing (122) may be made of a material having relatively high rigidity, such as metal, and defines the appearance 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.

[0055] The MTB housing (122) may include a through hole (122h) exposing the electrode terminal portion (124) described below. The through hole (122h) may be provided in the MTB housing (122) so that the electrode terminal portion (124) is exposed toward the second direction (e.g., Y-axis direction). Therefore, the through hole (122h) may be provided on a plane perpendicular to the second direction (e.g., Y-axis direction) of the MTB housing (122). In addition, 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 shape of the portion where the electrode terminal portion (124) is exposed to the outside.

[0056] A person skilled in the art will understand that the first MTB (120a) may further include, as necessary, a through hole for a venting disc, a through hole for a check valve, and a through hole for an electrolyte injection port, as described later.

[0057] The electrode terminal portion (124) is accommodated within the MTB housing (122) and can be exposed through the through hole (122h). The electrode terminal portion (124) can be made of a metal or metal alloy having low electrical resistance, and can be, for example, an alloy containing copper (Cu), aluminum (Al), nickel (Ni), iron (Fe), platinum (Pt), manganese (Mn), or one or more thereof.

[0058] In some embodiments, the exposed surface of the electrode terminal portion (124) facing outward from the MTB housing (122) may be a plane. In some embodiments, the exposed surface may have a plane extending perpendicular to the second direction (e.g., the Y-axis direction).

[0059] In some embodiments, an electrically insulating spacer 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).

[0060] In some embodiments, the first MTB (120a) may include a venting disk (126) configured to rupture when the internal pressure of the secondary battery (100) excessively increases, thereby releasing gas that causes the excessively increased internal pressure. The venting disk (126) is not restored to its original state when it ruptures due to a thermal event occurring within the secondary battery (100). The venting disk (126) may be any venting disk known in the art and is not particularly limited.

[0061] In some embodiments, the MTB housing (122) may further include a fusion resin layer (122p) on the side.

[0062] The above-mentioned 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.

[0063] The above polyolefin resin includes, for example, polyethylene, polypropylene, poly(1-butene), poly(4-methyl-1-pentene), an ethylene-propylene copolymer, a copolymer of ethylene and an α-olefin having 4 or more carbon atoms, a copolymer of polyolefin and maleic anhydride, an ethylene-vinyl ester copolymer, an ethylene-acrylic acid ester copolymer, or a modified polyolefin obtained by graft-modifying these with an unsaturated carboxylic acid or a derivative thereof, but the present invention is not limited thereto.

[0064] The above polyester resin includes polyethylene terephthalate, polybutylene terephthalate, or polyethylene naphthalate, but the present invention is not limited thereto.

[0065] The above polyamide resin includes nylon 6, nylon 6·6, nylon 6 / 66 copolymer, nylon 11, nylon 12, or poly(m-xylene adipamide), but the present invention is not limited thereto.

[0066] The above-mentioned fusion resin layer (122p) may be cast, or may be stretched or rolled in one or two axes.

[0067] In some embodiments, the fusion resin layer (122p) may at least partially cover a side surface of the MTB housing (122). In some embodiments, the fusion resin layer (122p) may extend from 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 an end adjacent to the electrode lead (116). In some embodiments, the fusion resin layer (122p) may surround a 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 of the MTB housing (122) with a predetermined width between the inner end (122ie) and the outer end (122oe).

[0068] In some embodiments, the fusion resin layer (122p) may surround a side surface of the MTB housing (122) while having a constant width between the inner end (122ie) and the outer end (122oe). In some embodiments, the fusion resin layer (122p) may extend in a first direction (e.g., X-axis direction) and / or a third direction (e.g., Z-axis direction) while having a constant width between the inner end (122ie) and the outer end (122oe).

[0069] In some embodiments, the fusion resin layer (122p) may extend along the side of the MTB housing (122) with a constant width between the inner end (122ie) and the outer end (122oe).

[0070] In some embodiments, the fusion resin layer (122p) may cover the entire side surface of the MTB housing (122).

[0071] The above-mentioned 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 from about 20 μm to about 400 μm, from about 30 μm to about 380 μm, from about 40 μm to about 360 μm, from about 50 μm to about 340 μm, from about 60 μm to about 320 μm, from about 70 μm to about 300 μm, from about 80 μm to about 280 μm, from about 90 μm to about 260 μm, from about 100 μm to about 240 μm, from about 110 μm to about 220 μm, from about 120 μm to about 200 μm, from about 130 μm to about 180 μm, from about 140 μm to about 160 μm, or a range between any two of these values.

[0072] If the thickness of the above-mentioned fusion resin layer (122p) is too thin, the mechanical strength may be insufficient. If the thickness of the above-mentioned fusion resin layer (122p) is too thick, it may be economically disadvantageous.

[0073] The above-mentioned fusion resin layer (122p) may be fused with the laminate sheet (130). In some embodiments, the above-mentioned fusion resin layer (122p) may extend from an end portion (130e) of the laminate sheet (130). In some embodiments, the above-mentioned fusion resin layer (122p) may extend from an end portion (130e) of the laminate sheet (130) toward the outer end portion (122oe).

[0074] 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) becomes higher than a predetermined pressure, and to close again when the internal pressure is relieved by the discharge of the gas. The check valve (128) does not have a part that is ruptured by the discharge of the gas, and can be restored to its original state after the discharge of the internal gas.

[0075] In some embodiments, the first MTB (120a) may further include an electrolyte injection port (127) capable of injecting an electrolyte. In some embodiments, the electrolyte injection port (127) may be provided in only one of the first MTB (120a) and the second MTB (120b).

[0076] The electrolyte injected through the electrolyte injection port (127) may be an electrolyte used for a typical lithium secondary battery, and is not particularly limited.

[0077] A bus bar may be further provided within the above first MTB (120a). Fig. 4 is a schematic diagram showing a cross-section of the first MTB (120a) cut along a plane passing through the electrode terminal portion (124) and perpendicular to the third direction (e.g., the Z-axis direction).

[0078] Referring to FIG. 4, the 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 including one or more of these.

[0079] 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 joined to the electrode lead (116) by welding. In some embodiments, the bus bar (125) may be joined to the electrode lead (116) by a fastener, for example, by a rivet.

[0080] In some embodiments, the bus bar (125) may include a center portion (125c) having a planar shape extending horizontally in the first direction (e.g., X-axis direction) and an edge portion (125e) extending by bending from the center portion (125c). The center portion (125c) may be configured to form a generally U-shaped cross-sectional shape together with the edge portion (125e) and may extend in the third direction (e.g., Z-axis direction). In some embodiments, the edge portion (125e) may have a plane extending perpendicularly to the first direction (e.g., X-axis direction).

[0081] The above bus bar (125) can make surface contact with the electrode terminal portion (124) at the center portion (125c). The above bus bar (125) can make surface contact with the electrode lead (116) at the edge portion (125e).

[0082] 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 being concentrated at a specific portion of the electrode lead (116) due to an external force applied to the stacked electrode assembly (110), thereby improving safety.

[0083] Since the secondary battery (100) of the present invention accommodates all units having respective functions within the MTB (120a, 120b), such as an electrode terminal portion (124), a bus bar (125), a venting disk (126), a check valve (128), and an electrolyte injection port (127), the battery cell itself has a function equivalent to a conventional battery module. Therefore, the secondary battery (100) of the present invention can have a high degree of freedom and compatibility, and is advantageous for implementing cell-to-pack.

[0084]

[0085] Fig. 5 is a partially exploded perspective view showing a method of joining a laminate sheet (130) of a secondary battery (100) according to one embodiment of the present invention. Fig. 6 is a partial cross-sectional view of a laminate sheet (130) according to one embodiment of the present invention.

[0086] Referring to FIGS. 5 and 6, the laminate sheet (130) may be configured to wrap around a side surface of the stacked electrode assembly (110). In some embodiments, the laminate sheet (130) may be attached to a side surface of the MTB (120a, 120b) so as to at least partially cover the side surface of the MTB (120a, 120b). In some embodiments, the laminate sheet (130) may cover all of the side surfaces of the MTB (120a, 120b) that are parallel to the second direction (e.g., the Y-axis direction). In some other embodiments, the laminate sheet (130) may cover only a portion of the side surfaces of the MTB (120a, 120b) that are parallel to the second direction (e.g., the Y-axis direction).

[0087] The above 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).

[0088] The metal layer (134) can maintain an appropriate thickness and prevent water vapor, oxygen, and other gases from penetrating from the outside to the inside, and can prevent electrolyte leakage. In some embodiments, the metal layer (134) may include at least one selected from iron (Fe), carbon (C), chromium (Cr), manganese (Mn), nickel (Ni), aluminum (Al), and alloys thereof, but is not limited thereto. When the metal layer (134) is made of a material containing iron, the mechanical strength is strengthened, and when it is made of an aluminum material, the flexibility is improved, and thus, aluminum metal foil is mainly used.

[0089] The above metal layer (134) can be relatively easily deformed by a force applied from the outside, and can be configured to have an appropriate thickness and mechanical strength so that cracks or holes do not occur even when repeatedly deformed.

[0090] 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 have a range of 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 any two of these values.

[0091] The internal resin layer (132) provided on one side of the metal layer (134) may include a heat-sealing layer. In some embodiments, the internal resin layer (132) may include a polyolefin-based material capable of performing a sealing function through fusion. In some embodiments, the internal resin layer (132) may include a modified propylene such as cast polypropylene (CPP), or a polypropylene-butylene-ethylene terpolymer.

[0092] The above inner resin layer (132) can be formed by coating or laminating one side of the above metal layer (134).

[0093] The external resin layer (136) provided on the other side of the metal layer (134) can act as a base substrate and a protective layer for forming the laminate sheet (130). The external resin layer (136) can include an insulating material such as polyethylene terephthalate (PET) or nylon.

[0094] 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 each of the inner resin layer (132) and the outer resin layer (136) may have a thickness of 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.

[0095] 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 for 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.

[0096] In some embodiments, the inner resin layer (132) may be fused to a fusion resin layer (122p) provided on the side surfaces of the MTBs (120a, 120b) at both ends in the second direction (e.g., Y-axis direction). The inner resin layer (132) may be fused to the fusion resin layer (122p) while surrounding the side surfaces of the MTBs (120a, 120b), thereby allowing the stacked electrode assembly (110) to be encapsulated within the secondary battery. The inner resin layer (132) may be melted by heating while in contact with the fusion resin layer (122p) on the side surfaces of the MTBs (120a, 120b) and then cooled to be fused onto the side surfaces.

[0097] The above laminate sheet (130) can be placed so that the inner resin layers (132) face each other at the joint (130m) after surrounding the side surfaces of the MTBs (120a, 120b) and the stacked electrode assembly (110), and then the inner resin layers (132) facing each other can be fused together.

[0098] The above-mentioned joining part (130m) may be positioned on any one side of the stacked electrode assembly (110). In some embodiments, the joining part (130m) may surround the stacked electrode assembly (110) and be positioned in a third direction (e.g., the Z-axis direction) of the stacked electrode assembly (110).

[0099] As described above, in the secondary battery (100) of the present invention, since the stacked electrode assembly (110) is directly surrounded by the laminate sheet (130) without a forming process for the laminate sheet (130), unit cells can be accommodated with a thickness greater than that defined in the conventional forming process. Therefore, the secondary battery (100) of the present invention is advantageous in implementing a large-capacity cell.

[0100]

[0101] FIG. 7 is a cross-sectional view showing a main portion of a cross-section of a first MTB (120a) and a laminate sheet (130) according to one embodiment of the present invention taken along line VII-VII' of FIG. 5.

[0102] Referring to Fig. 7, the laminate sheet (130) can be fused with the fusion resin layer (122p). More specifically, the inner resin layer (132) of the laminate sheet (130) can be fused with the fusion resin layer (122p).

[0103] In Fig. 7, an interface is shown to exist between the inner resin layer (132) and the fusion resin layer (122p), but this is for convenience of understanding, and in reality, an interface may not be confirmed between the inner resin layer (132) and the fusion resin layer (122p).

[0104] As illustrated in FIG. 7, the fusion resin layer (122p) may extend somewhat from the end (130e) of the laminate sheet (130) toward the outer end (122oe) of the side of the MTB housing (122). In some embodiments, the end (130e) of the laminate sheet (130) may extend further toward the outer end (122oe) than the end of the fusion resin layer (122p).

[0105]

[0106] Fig. 8 is a cross-sectional view showing a main portion of a first MTB (120a) and a laminate sheet (130) according to another embodiment of the present invention, taken along the line VII-VII' of Fig. 5. The embodiment illustrated in Fig. 8 is substantially the same as the embodiment illustrated in Fig. 7, except that a melted protrusion (132d) is further formed at the end (130e) of the laminate sheet (130). Therefore, the following description will focus on these differences.

[0107] Referring to FIG. 8, the inner resin layer (132) may further include a molten protrusion (132d) at the end (130e) of the laminate sheet (130). The molten protrusion (132d) may be a structure formed when the molten inner resin layer (132) partially flows to the outside of the end (130e) of the laminate sheet (130) and then solidifies when the inner resin layer (132) is melted to be fused to the fused resin layer (122p). In some embodiments, the molten protrusion (132d) may be formed when the inner resin layer (132) flows to the outside due to pressure applied to the laminate sheet (130) for fusion of the laminate sheet (130).

[0108]

[0109] Figure 9 is a schematic diagram illustrating the main portion of the outer surface of a first MTB (120a) according to one embodiment of the present invention. Those skilled in the art will understand that the configuration of the first MTB (120a) described with reference to Figure 9 can be equally applied to the second MTB (120b).

[0110] Referring to FIG. 9, the outer surface of the MTB housing (122) of the first MTB (120a) can be at least partially roughened.

[0111] In some embodiments, the roughening may be performed by surface etching. In some embodiments, the surface etching may be performed by wet etching or dry etching. In some embodiments, the surface etching may be performed chemically using a liquid etchant. In some embodiments, the surface etching may be performed by irradiation with plasma, laser, radicals, and / or ions.

[0112] As illustrated in FIG. 9, a roughened surface (122r) may be formed over the entire outer surface of the MTB housing (122). The MTB housing (122) may include a roughened surface (122r) on the entire upper surface, lower surface, left surface, and right surface of the MTB housing (122) illustrated in FIG. 9.

[0113] The above roughened surface (122r) may have a roughness of about 0.1 ㎛ to about 50 ㎛ based on the arithmetic average roughness (Ra). In some embodiments, the roughness of the roughened surface (122r) is about 0.1 μm to about 50 μm, about 0.3 μm to about 48 μm, about 0.5 μm to about 45 μm, about 0.8 μm to about 43 μm, about 1 μm to about 40 μm, about 1.3 μm to about 38 μm, about 1.5 μm to about 35 μm, about 1.8 μm to about 33 μm, about 2 μm to about 30 μm, about 2.5 μm to about 28 μm, about 3 μm to about 25 μm, about 3.5 μm to about 23 μm, about 4 μm to about 20 μm, about 5 μm to about 18 μm, about 6 μm to about 15 μm, about 7 μm to about 13 ㎛, about 8 ㎛ to about 10 ㎛, or a range between any two of these values.

[0114] The roughened surface (122r) can improve the adhesion between the fusion resin layer (122p) and the MTB housing (122). If the roughness of the roughened surface (122r) is too small, the effect of improving the adhesion between the fusion resin layer (122p) and the MTB housing (122) may be insufficient. If the roughness of the roughened surface (122r) is too large, the MTB housing (122) may damage other parts that rub against it.

[0115] The roughened surface (122r) may be at least partially covered by the fusion resin layer (122p). In some embodiments, the fusion resin layer (122p) may overlap only a portion of the roughened surface (122r). The fusion resin layer (122p) may extend from the inner end (122ie) of the side surface of the MTB housing (122) toward the outer end (122oe). In some embodiments, the fusion resin layer (122p) may not extend to the outer end (122oe). However, the fusion resin layer (122p) may extend further from the end (130e) of the laminate sheet toward the outer end (122oe).

[0116] The embodiment described with reference to FIG. 9 is capable of roughening the entire side surface of the MTB housing (122) and forming a fusion resin layer (122p) only on the necessary portions thereof. Therefore, the workability for forming the fusion resin layer (122p) is excellent.

[0117]

[0118] Fig. 10 is a schematic diagram illustrating the outer surface of a first MTB (120a) according to another embodiment of the present invention. Those skilled in the art will understand that the configuration of the first MTB (120a) described with reference to Fig. 10 can be equally applied to the second MTB (120b).

[0119] Referring to FIG. 10, the outer surface of the MTB housing (122) of the first MTB (120a) may be partially roughened.

[0120] As illustrated in FIG. 10, a roughened surface (122r) may be formed over a portion of the outer surface of the MTB housing (122). The MTB housing (122) may include a roughened surface (122r) that is roughened over a predetermined width from the inner end (122ie) toward the outer end (122oe) of the upper surface, lower surface, left surface, and right surface of the MTB housing (122) illustrated in FIG. 10.

[0121] In some embodiments, the fusion resin layer (122p) may overlap the entire surface of the roughened surface (122r). In some embodiments, the side surface of the MTB housing (122) covered by the fusion resin layer (122p) may substantially coincide with the surface of the roughened surface (122r). In other words, the area occupied by the fusion resin layer (122p) and the area occupied by the roughened surface (122r) on the surfaces of the upper surface, lower surface, left surface, and right surface of the MTB housing (122) may be substantially the same.

[0122] In the embodiment described with reference to FIG. 10, productivity can be improved because roughening is performed only on the necessary portions of the side of the MTB housing (122).

[0123]

[0124] Fig. 11 is a schematic diagram illustrating the outer surface of a first MTB (120a) according to another embodiment of the present invention. Those skilled in the art will understand that the configuration of the first MTB (120a) described with reference to Fig. 11 can be equally applied to the second MTB (120b).

[0125] Referring to FIG. 11, the outer surface of the MTB housing (122) of the first MTB (120a) may be partially roughened.

[0126] As illustrated in FIG. 11, a roughened surface (122r) may be formed over a portion of the outer surface of the MTB housing (122). The MTB housing (122) may include a roughened surface (122r) that is roughened over a predetermined width from the inner end (122ie) toward the outer end (122oe) of the upper surface, lower surface, left side, and right side of the MTB housing (122) illustrated in FIG. 10.

[0127] In some embodiments, the fusion resin layer (122p) may overlap the entire surface of the roughened surface (122r). Furthermore, the fusion resin layer (122p) may also contact a side surface of the MTB housing (122) that is not roughened beyond the surface of the roughened surface (122r).

[0128] In the embodiments of FIGS. 9 to 11, the inner end of the roughened surface (122r) is illustrated as being aligned with the inner end (122ie) of the side surface of the MTB housing (122), but the present invention is not limited thereto. In some embodiments, when forming the roughened surface (122r), an unroughened portion may be interposed between the inner end of the roughened surface (122r) and the inner end (122ie) of the side surface of the MTB housing (122) in order to protect other parts of the MTB housing (122).

[0129] In the embodiments of FIGS. 9 to 11, the inner end of the fusion resin layer (122p) is illustrated as being aligned with the inner end (122ie) of the side surface of the MTB housing (122), but the present invention is not limited thereto. In some embodiments, the fusion resin layer (122p) may be formed so that the inner end of the fusion resin layer (122p) is spaced apart from the inner end (122ie) of the side surface of the MTB housing (122) by a predetermined distance in consideration of a work error in the process.

[0130] In the embodiments of FIGS. 9 to 11, the inner end of the fusion resin layer (122p) is illustrated as being aligned with the inner end of the roughened surface (122r), but the present invention is not limited thereto. In some embodiments, the inner end of the fusion resin layer (122p) may be positioned between the inner end (122ie) of the side surface of the MTB housing (122) and the inner end of the roughened surface (122r). In some other embodiments, the inner end of the roughened surface (122r) may be positioned between the inner end (122ie) of the side surface of the MTB housing (122) and the inner end of the fusion resin layer (122p).

[0131]

[0132] (Example 2)

[0133] Fig. 12a is a perspective view showing the main part of a secondary battery (100a) according to another embodiment of the present invention. Fig. 12b is a partial perspective view showing an enlarged portion of a part of the secondary battery (100a) of Fig. 12a. Fig. 13 is a side view of a secondary battery (100a) according to another embodiment of the present invention.

[0134] The above secondary battery (100a) differs from the embodiment described with reference to FIGS. 1 to 11 in that the MTB is provided only on one side of the stacked electrode assembly extending in the second direction (e.g., the Y-axis direction). Therefore, the following description will focus on these differences, and any overlapping portions will be omitted for further explanation.

[0135] Referring to FIGS. 12a to 13, since the MTB (120c) is provided only on one side of the stacked electrode assembly, not on both sides, both electrodes of the stacked electrode assembly are connected to the MTB (120c). That is, the MTB (120c) is provided only on one side of the stacked electrode assembly in the second direction (e.g., Y-axis direction), and the joint portion (130m) can be extended without the MTB on the other side of the stacked electrode assembly in the second direction (e.g., Y-axis direction).

[0136] Since the MTB is provided on only one side of the stacked electrode assembly, the MTB (120c) is provided with a first electrode terminal portion (124a) and a second electrode terminal portion (124b) of different polarities. One of the first electrode terminal portion (124a) and the second electrode terminal portion (124b) may be a terminal portion corresponding to the cathode, and the other may be a terminal portion corresponding to the anode.

[0137] In FIG. 6b, a venting disk (126) is shown as being provided between the first electrode terminal portion (124a) and the second electrode terminal portion (124b), but the relative positions of the first electrode terminal portion (124a), the second electrode terminal portion (124b), and the venting disk (126) within the MTB (120c) are not particularly limited.

[0138] The bonding portion (130m) of the laminate sheet (130) can extend in a second direction (e.g., the Y-axis direction) from one side (the upper side in FIG. 13) of the stacked electrode assembly in the third direction (e.g., the Z-axis direction). Furthermore, the bonding portion (130m) can extend in the third direction (e.g., the Z-axis direction) from the other side. In FIG. 13, the stacked electrode assembly is surrounded by the laminate sheet (130).

[0139] While the embodiments of the present invention have been described in detail above, those skilled in the art will appreciate that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention as defined in the appended claims. Therefore, modifications to future embodiments of the present invention will not depart from the scope of the invention.

Claims

1. A stacked electrode assembly in which a plurality of unit cells are stacked in a first direction and have electrode leads at both ends in a second direction perpendicular to the first direction; A multifunctional terminal block (MTB) provided at both ends of the stacked electrode assembly; and A laminate sheet covering the side of the stacked electrode assembly; Including, The above MTB is a secondary battery including a fusion resin layer on the side.

2. In paragraph 1, The above laminate sheet at least partially overlaps the side of the MTB, A secondary battery characterized in that the laminate sheet is fused with the fusion resin layer.

3. In paragraph 2, The above laminate sheet: A metal layer having flexibility; An internal resin layer provided on one side of the metal layer; and An outer resin layer provided on the other side of the metal layer; Including, A secondary battery characterized in that the inner resin layer comprises casted polypropylene (CPP).

4. In paragraph 3, A secondary battery characterized in that the above-mentioned fusion resin layer is fused with the above-mentioned inner resin layer.

5. In paragraph 3, A secondary battery characterized in that the above-mentioned fusion resin layer comprises a polypropylene resin.

6. In paragraph 3, A secondary battery, characterized in that the above-mentioned fusion resin layer includes an extension portion extending along a side surface of the MTB from an end of the above-mentioned laminate sheet.

7. In paragraph 3, A secondary battery characterized in that the side of the above MTB is at least partially roughened.

8. In paragraph 7, A secondary battery characterized in that the above-mentioned fusion resin layer covers the roughened portion of the above-mentioned MTB.

9. In paragraph 7, A secondary battery characterized in that the side of the above MTB is roughened by surface etching.

10. In paragraph 1, The above MTB is, An electrode terminal electrically connected to the electrode lead of the stacked electrode assembly; and A venting disk that ruptures to release gas when internal pressure increases; A secondary battery characterized by including:

11. In paragraph 1, A secondary battery characterized in that the above MTB further includes a bus bar electrically connecting the electrode lead of the stacked electrode assembly and the electrode terminal portion.

12. A stacked electrode assembly in which a plurality of unit cells are stacked in a first direction, extend in a second direction perpendicular to the first direction, and have electrode leads at their ends; A multifunctional terminal block (MTB) coupled to the electrode lead of the stacked electrode assembly and including an electrode terminal portion and a bus bar; and A laminate sheet wrapping the stacked electrode assembly together with the MTB; Includes, The side of the above MTB is a roughened secondary battery.

13. In paragraph 12, A secondary battery characterized in that the roughened side of the above MTB is at least partially covered by a fusion resin layer.

14. In paragraph 13, The above laminate sheet: A metal layer having flexibility; An internal resin layer provided on one side of the metal layer; and An outer resin layer provided on the other side of the metal layer; Including, A secondary battery characterized in that the outer resin layer is fused with the fusion resin layer.

15. In paragraph 13, A secondary battery, characterized in that the above-mentioned fusion resin layer includes an extension portion extending along a side surface of the MTB from an end of the above-mentioned laminate sheet.

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