Secondary battery and method for manufacturing the same

Abstract

A secondary battery is provided, comprising: a stacked electrode assembly in which a plurality of cell cells are stacked in a first direction and the plurality of cell cells have electrode leads at both ends in a second direction perpendicular to the first direction; a multifunctional terminal block (MTB) disposed at both ends of the stacked electrode assembly; and a laminate surrounding a side surface of the stacked electrode assembly, wherein the side surface of the MTB includes a fusion resin layer having a locally increased thickness.

Description

Technical Field

[0001] This disclosure relates to a secondary battery and a method for manufacturing the same, and more specifically, to a secondary battery with improved safety and superior productivity, and a method for manufacturing the same.

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0167377, filed on November 28, 2023, the entire contents of which are incorporated herein by reference. Background Technology

[0003] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. They are widely used as an energy source for various wireless devices, such as mobile phones, laptops, and cordless vacuum cleaners. Recently, as the manufacturing cost per unit capacity of secondary batteries has decreased significantly due to increased energy density and economies of scale, and as the cruising range of battery electric vehicles (BEVs) has increased to a level comparable to that of fuel cell vehicles, the primary use of secondary batteries has shifted from mobile devices to mobility services.

[0004] As rechargeable batteries are used in mobility applications, the need for their safety is increasing. In the event of an accident such as a fire involving a rechargeable battery used in mobility services, the driver's lifespan could be threatened; therefore, research into technologies to improve the safety of rechargeable batteries is crucial. Summary of the Invention

[0005] Technical issues

[0006] The first technical problem this disclosure aims to solve is to provide a secondary battery with improved safety and excellent productivity.

[0007] The second technical problem to be solved by this disclosure is to provide a method for manufacturing a secondary battery with improved safety and excellent productivity.

[0008] Technical solution

[0009] To address the first technical problem, this disclosure provides a secondary battery comprising: a stacked electrode assembly in which multiple cell units are stacked in a first direction and the multiple cell units have electrode leads at both ends in a second direction perpendicular to the first direction; a multifunctional terminal block (MTB) disposed at both ends of the stacked electrode assembly; and a laminate surrounding a side surface of the stacked electrode assembly, wherein the side surface of the MTB includes a fusion resin layer having a locally increased thickness.

[0010] In some embodiments, the bonding portion of the laminate may be located at a position where the fused resin layer has a locally increased thickness.

[0011] In some embodiments, the fusion resin layer is a polymer film, and the location of the fusion resin layer with locally increased thickness may have increased thickness compared to other locations due to the greater number of polymer film coatings.

[0012] In some embodiments, the fusion resin layer may include an extension extending from the edge of the laminate along the side surface of the MTB.

[0013] In some embodiments, the thickness of the fusion resin layer at locations in the extension where the thickness is locally increased may be about 1.8 to about 2.2 times the thickness of the fusion resin layer at other locations in the extension.

[0014] In some embodiments, the joint may be located approximately at the center of the secondary battery in the first direction.

[0015] In some embodiments, the fusion resin layer is a polymer ring fused to the periphery of the MTB housing, and the location where the fusion resin layer has a locally increased thickness can be a portion where tension is applied to the polymer ring when it is fused to the periphery of the MTB housing.

[0016] In some embodiments, the fusion resin layer may extend at least partially between the joints.

[0017] In some embodiments, the length of the fusion resin layer extending between the joints can be from about 0.1 mm to about 2 mm.

[0018] To address the second technical problem, this disclosure provides a method for manufacturing a secondary battery, the method comprising: attaching a multifunctional terminal block (MTB) to both ends of a stacked electrode assembly, the stacked electrode assembly including a plurality of cell 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 around the periphery of the MTB housing of the MTB; and bonding a laminate to the fusion resin layer to surround a side surface of the stacked electrode assembly, wherein the fusion resin layer has a locally increased thickness, and the laminate has a bonding portion at the location where the fusion resin layer has the locally increased thickness.

[0019] In some embodiments, the step of forming the fusion resin layer may include the step of locally forming an overlapping layer of the polymer film.

[0020] In some embodiments, the polymer film may be configured to partially overlap the side surface of the MTB housing.

[0021] In some embodiments, the step of forming the fused resin layer may include: providing a polymer ring around the periphery of the MTB housing, wherein the inner length of the polymer ring is 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 rings together.

[0022] In some embodiments, the location where the polymer rings are fused together during the step of fusing the remaining length of the polymer rings together may substantially coincide with the location where the laminate has a bonding portion.

[0023] In some embodiments, an electrode terminal portion electrically connected to the electrode leads of the stacked electrode assembly and a busbar electrically connecting the electrode leads of the stacked electrode assembly to the electrode terminal portion are provided within the MTB housing, and the laminate includes: a flexible metal layer; an inner resin layer disposed on one side of the metal layer; and an outer resin layer disposed on the other side of the metal layer, wherein the inner resin layer may contain cast polypropylene (CPP).

[0024] Beneficial effects

[0025] The secondary battery disclosed herein can have improved safety due to its excellent sealing reliability, and can have increased productivity due to its ease of manufacture.

[0026] However, the technical effects achievable in the exemplary embodiments of this disclosure are not limited to those described above, and those skilled in the art will clearly understand from the description of this disclosure below that other effects not mentioned are possible. In other words, those skilled in the art can also derive unintended effects from the exemplary embodiments of this disclosure. Attached Figure Description

[0027] Figure 1 This is a perspective view showing a key portion of a secondary battery according to an embodiment of the present disclosure.

[0028] Figure 2 It is shown Figure 1 A magnified partial perspective view of the secondary battery.

[0029] Figure 3 It shows from Figure 1 A schematic perspective view of a secondary battery with the laminate removed.

[0030] Figure 4 This is a side view of a secondary battery according to an embodiment of the present disclosure, viewed from a second direction.

[0031] Figure 5 yes Figure 4 An enlarged view of the portion represented by P.

[0032] Figure 6 This is a side view of a secondary battery according to another embodiment of the present disclosure, viewed in a second direction.

[0033] Figure 7 This is a partially exploded perspective view illustrating a method for bonding laminates of a secondary battery according to an embodiment of the present disclosure.

[0034] Figure 8 This is a partial cross-sectional view of a laminate according to an embodiment of the present disclosure.

[0035] Figure 9 This is a schematic diagram showing an important portion of the extension exposed from the edge of the laminate.

[0036] Figure 10 It shows along Figure 7 A cross-sectional view of the first MTB and the important part of the laminate section cut by line X-X'.

[0037] Figure 11 This is a partially exploded perspective view illustrating a method for bonding laminates of a secondary battery according to another embodiment of the present disclosure.

[0038] Figure 12 This is a flowchart illustrating a method for manufacturing a secondary battery according to an embodiment of the present disclosure.

[0039] Figure 13 , Figure 14 and Figure 19 This is a perspective or side view illustrating a method for manufacturing a secondary battery according to an embodiment of the present disclosure.

[0040] Figures 15 to 17 This is a diagram illustrating one embodiment of a method for forming a fused resin layer.

[0041] Figure 18 This is a diagram illustrating another embodiment of a method for forming a fused resin layer.

[0042] Figure 20 This is a schematic perspective view of a battery pack according to an embodiment of the present disclosure.

[0043] Figure 21 It is shown schematically. Figure 20 An exploded perspective view of the battery pack configuration.

[0044] Figure 22 It is shown Figure 21 A perspective view of individual battery cells housed within the battery pack casing. Detailed Implementation

[0045] In the following, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. However, embodiments of the present disclosure may be modified in various different forms and should not be construed as limiting the scope of the present disclosure to the embodiments described below. Preferably, embodiments of the present disclosure are intended to provide a more thorough explanation of the disclosure to those skilled in the art. Throughout this document, the same reference numerals refer to the same elements. Furthermore, various elements and areas are schematically shown in the drawings. Therefore, the present disclosure is not limited to the relative dimensions or spacing shown in the drawings.

[0046] Terms such as "first," "second," etc., may be used to describe various components, but components are not limited by these terms. These terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the concepts of this disclosure, a first component may be referred to as a second component, and vice versa.

[0047] The terminology used in this specification is for illustrative purposes only and is not intended to limit the concepts of this disclosure. Unless the context clearly indicates otherwise, the singular forms include the plural. The terms “comprise,” “include,” and “have” as used herein mean the presence of the features, quantities, steps, operations, components, or elements or combinations thereof described in the specification, and it should be understood that the possibility of the presence or addition of one or more other features, quantities, steps, operations, components, elements, or combinations thereof is not excluded in advance.

[0048] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which the concepts of this disclosure pertain. Furthermore, it should be understood that, unless expressly defined herein, terms such as commonly used, dictionary-defined terms shall be interpreted as having the same meaning as they have in the context of the art to which they pertain, and not as having an overly formal meaning.

[0049] When some embodiments are implemented in other ways, certain process steps may be performed in a different order than described. For example, two processes described consecutively may be performed substantially simultaneously, or they may be performed in the reverse order of description.

[0050] In the accompanying drawings, variations in form may be depicted, for example, depending on manufacturing techniques and / or tolerances. Therefore, embodiments of this disclosure should not be construed as limited to the specific forms shown herein and should include variations in form, for example, those resulting from manufacturing processes. All terms “and / or” as used herein include each combination of one or more of the mentioned components. Furthermore, the term “substrate” as used herein may refer to the substrate itself, or to a stacked structure comprising the substrate and any specified layers or films formed on its surface. Additionally, the term “surface of substrate” as used herein may refer to the exposed surface of the substrate itself, or to the outer surface of specified layers or films formed on the substrate.

[0051] (First embodiment)

[0052] Figure 1 This is a perspective view showing a significant portion of a secondary battery 100 according to an embodiment of the present disclosure. Figure 2 It is shown Figure 1 A partial perspective view of the magnified portion of the secondary battery 100. Figure 3 It shows from Figure 1 A schematic perspective view of a secondary battery 100 with the laminate 130 removed.

[0053] In the following figures, the secondary battery 100 is shown as defined in a vertical coordinate system by a first direction perpendicular to each other along the X-axis, a second direction perpendicular to each other along the Y-axis, and a third direction perpendicular to each other along the Z-axis. However, the first direction, the second direction, and the third direction only need to be perpendicular to each other and are not specifically limited.

[0054] Reference Figures 1 to 3 The secondary battery 100 includes a stacked electrode assembly 110, multi-functional terminal blocks (MTBs) 120a and 120b, and a laminate 130.

[0055] The stacked electrode assembly 110 may include a plurality of cell cells 111 stacked in a first direction (e.g., the X-axis direction). Each cell cell 111 may have electrode material coated on a metal foil used as a current collector.

[0056] Each cell 111 may have a thin plate-shaped body extending in a second direction (e.g., the Y-axis direction). Each cell 111 may be a positive cell or a negative cell. In some embodiments, multiple cells 111 may be stacked alternately with one positive cell and one negative cell. The positive and negative cells may be separated from each other by a separator.

[0057] In some other embodiments, the multiple cell units 111 may be stacked alternately as multiple positive cell units and multiple negative cell units. The multiple positive cell units and multiple negative cell units may be separated from each other by a separator.

[0058] In some other embodiments, the multiple cell units 111 may be stacked alternately as multiple positive cell units and multiple negative cell units. The multiple positive cell units and multiple negative cell units may be separated from each other by a separator.

[0059] The stacked electrode assembly 110 may have electrode leads 116 at both ends in a second direction (e.g., the Y-axis direction). The electrode leads 116 may be electrically connected to electrode tabs of a plurality of cell units 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.

[0060] The stacked electrode assembly 110 may include a first electrode stack 110a that is stacked in a first direction (e.g., the X-axis direction) and shares an electrode lead 116, and a second electrode stack 110b that is stacked in the first direction (e.g., the X-axis direction) and shares another electrode lead 116.

[0061] 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. Furthermore, 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, this disclosure is not limited thereto.

[0062] A first MTB 120a may be disposed at one end of the stacked electrode assembly 110 in a second direction (e.g., the Y-axis direction), and a second MTB 120b may be disposed 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, differing only in polarity. The first MTB 120a will be described below, but those skilled in the art will be able to understand the configuration of the second MTB 120b from this specification.

[0063] In some embodiments, the first MTB 120a may include an MTB housing 122, an electrode terminal portion 124 housed in the MTB housing 122, and a busbar 125 electrically connecting the electrode terminal portion 124 and the electrode lead 116 (see reference). Figure 10 ).

[0064] The MTB housing 122 may contain a material with relatively high rigidity, such as a metal, and define 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.

[0065] The MTB housing 122 may include a through-hole 122h exposing the electrode terminal portion 124, as 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 toward a 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 opens along the length of the electrode assembly 110. The shape of the through-hole 122h may be configured to conform to the external shape of the exposed portion of the electrode terminal portion 124.

[0066] In some embodiments, the exposed surface of the electrode terminal portion 124 exposed to the outside from the MTB housing 122 may be a plane. In some embodiments, the exposed surface may have a plane extending perpendicular to a second direction (e.g., the Y-axis direction). In some embodiments, the electrode terminal portion 124 may be exposed to the outside as a disc-shaped free surface.

[0067] In some embodiments, an electrical insulating washer 129 may be disposed between the electrode terminal portion 124 and the MTB housing 122, thereby electrically insulating the electrode terminal portion 124 from the MTB housing 122.

[0068] In some embodiments, the first MTB 120a may include a rupture disc configured to release gases causing an excessive increase in internal pressure by rupturing when the internal pressure of the secondary battery 100 increases excessively. Once the rupture disc ruptures due to a thermal event occurring inside the secondary battery 100, it does not return to its initial state. The rupture disc can be any rupture disc known in the art and is not specifically limited thereto.

[0069] In some embodiments, the MTB housing 122 may further include a fusion resin layer 122p on its side surface.

[0070] The fusion resin layer 122p is a thermoplastic resin layer, for example, it may comprise 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.

[0071] Polyolefin resins may include, for example, polyethylene, polypropylene, poly(1-butene), poly(4-methyl-1-pentene), ethylene-propylene copolymers, copolymers of ethylene and α-olefins having four or more carbon atoms, copolymers of polyolefins and maleic anhydride, ethylene-vinyl ester copolymers, ethylene-acrylate copolymers, or modified polyolefins grafted with unsaturated carboxylic acids or their derivatives, but this disclosure is not limited thereto.

[0072] In some embodiments, the polyester resin may comprise polyethylene terephthalate, polybutylene terephthalate, or polyethylene naphthalate, but this disclosure is not limited thereto.

[0073] In some embodiments, the polyamide resin may comprise nylon 6, nylon 6 6, nylon 6 / 66 copolymer, nylon 11, nylon 12 or poly(m-xylene adipamide), but this disclosure is not limited thereto.

[0074] In some embodiments, the fusion resin layer 122p can be cast, or can be stretched or rolled in a uniaxial or biaxial direction.

[0075] In some embodiments, the fusion resin layer 122p may at least partially coat the side surface of the MTB housing 122. In some embodiments, the fusion resin layer 122p may extend from the inner end 122ie or its vicinity on the side of the MTB housing 122 toward the outer end 122oe on the side 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 with 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 with a predetermined width between the inner end 122ie and the outer end 122oe.

[0076] In some embodiments, the fusion resin layer 122p may surround the side surface of the MTB housing 122 with a constant width between the inner end 122ie and the outer end 122oe. In some embodiments, the fusion resin layer 122p may extend with a constant width in a first direction (e.g., the X-axis direction) and / or a third direction (e.g., the Z-axis direction) between the inner end 122ie and the outer end 122oe.

[0077] In some embodiments, the fusion resin layer 122p may extend along the side surface of the MTB housing 122 with a constant width between the inner end 122ie and the outer end 122oe.

[0078] In some embodiments, the fusion resin layer 122p may coat the entire side surface of the MTB housing 122.

[0079] The fusion resin layer 122p may have a thickness of, for example, from 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.

[0080] If the thickness of the fusion resin layer 122p is too thin, the mechanical strength may be insufficient. If the thickness of the fusion resin layer 122p is too thick, it may be economically disadvantageous.

[0081] The fusion resin layer 122p can be fused to the laminate 130. In some embodiments, the fusion resin layer 122p can extend from the edge portion 130e of the laminate 130. In some embodiments, the fusion resin layer 122p can be exposed from the edge portion 130e of the laminate 130 and extend toward the outer end 122oe.

[0082] In some embodiments, the first MTB 120a may further include a check valve 128. The check valve 128 may be configured to open to release 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 released as the gas is released. The check valve 128 has no rupture due to gas release and can return to its initial state after the internal gas is released.

[0083] The secondary battery 100 further includes an electrolyte. The electrolyte can be a commonly used electrolyte for lithium secondary batteries, and there are no specific limitations. In some embodiments, the electrolyte can be injected just before the sealing laminate 130. In some embodiments, the electrolyte can be injected after the sealing laminate 130 through an electrolyte injection port provided in the first MTB 120a.

[0084] Figure 4This is a side view of a secondary battery 100 according to an embodiment of the present disclosure, as viewed in a second direction (e.g., the Y-axis direction).

[0085] Reference Figure 4 A fusion resin layer 122p can be provided between the MTB housing 122 and the laminate 130 surrounding the MTB housing 122. The fusion resin layer 122p can have locally increased thickness. Figure 4 In the diagram, the fused resin layer 122p is shown as having a locally increased thickness on the upper surface of the MTB housing 122, but this disclosure is not limited thereto.

[0086] In some embodiments, the fusion resin layer 122p may have a protrusion 122pp at a location where it has a locally increased thickness. The protrusion 122pp may be located adjacent to the bonding portion 130m that bonds to the laminate 130. Defects may occur where gaps are created due to insufficient bonding between the bonding portion 130m of the opposing laminate 130 and the MTB housing 122. Such defects may lead to problems such as electrolyte leakage or external moisture penetration.

[0087] However, in the secondary battery 100 of this disclosure, by placing the protrusion 122pp between the joint 130m and the MTB housing 122, defects such as gaps can be effectively prevented, thereby preventing problems such as electrolyte leakage or external moisture penetration.

[0088] In some embodiments, the coupling portion 130m may be located approximately at the center of the secondary battery 100 in a first direction (e.g., the X-axis direction). In some other embodiments, the coupling portion 130m may be located at... Figure 4 Near the corner of the MTB housing 122 shown.

[0089] In some embodiments, the fusion resin layer 122p may extend at least partially between the laminates 130 of the bonding portion 130m. The portion of the fusion resin layer 122p extending between the laminates 130 of the bonding portion 130m may be a protrusion 122pp.

[0090] The length (d) of the protrusions 122pp extending between the laminates 130 can be from about 0.1 mm to about 2 mm. In some embodiments, the extension length (d) can be a range from 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 any two of these values.

[0091] When the extension length (d) of the protrusion 122pp is too small or too large, the effect of preventing gap defects may be insufficient.

[0092] Figure 5 yes Figure 4 An enlarged view of the portion represented by P.

[0093] Reference Figure 5 The fusion resin layer 122p may include an overlapping layer in which two polymer films 122pf1 and 122pf2 overlap at a position adjacent to the bonding portion 130m. In some embodiments, the overlapping polymer films 122pf1 and 122pf2 may be the two ends of a single polymer film constituting the fusion resin layer 122p. That is, the polymer film may surround the MTB housing 122, and its two ends may overlap on one surface of the MTB housing 122.

[0094] exist Figure 5 In the diagram, polymer films 122pf1 and 122pf2 are represented by dashed lines, and depending on the circumstances, the interface between polymer films 122pf1 and 122pf2 may be identifiable, or the interface between polymer films 122pf1 and 122pf2 may be unidentifiable due to fusion. In some embodiments, such as Figure 5 As shown, due to the greater number of polymer film coatings compared to other locations, the locations where the fused resin layer 122p has a locally increased thickness (i.e., the protrusions 122pp) can have an increased thickness. However, this disclosure is not limited thereto.

[0095] Figure 6 This is a side view of a secondary battery 100 according to another embodiment of the present disclosure, as viewed in a second direction (e.g., the Y-axis direction). Although in reference... Figure 4 In the described embodiment, the joint 130m is located at the center of the secondary battery 100 in a first direction (e.g., the X-axis direction), but in Figure 6In one embodiment, the joint 130m is located near the corner of the MTB housing 122, and these two locations are different.

[0096] Reference Figure 6 The joint 130m can be located near any corner of the MTB housing 122. In some embodiments, the joint 130m can be located near one of the two corners of the four corners of the MTB housing 122 that are closer to the check valve 128. In some other embodiments, the joint 130m can be located near one of the two corners of the four corners of the MTB housing 122 that are further away from the check valve 128.

[0097] The protrusion 122pp can be located at a position substantially the same as the joint 130m. Therefore, the protrusion 122pp can be located near any corner of the MTB housing 122. In some embodiments, the protrusion 122pp can be located near one of the two corners of the four corners of the MTB housing 122 that is closer to the check valve 128. In some other embodiments, the protrusion 122pp can be located near one of the two corners of the four corners of the MTB housing 122 that is further away from the check valve 128.

[0098] Figure 7 This is a partially exploded perspective view showing a bonding method of the laminate 130 of a secondary battery 100 according to an embodiment of the present disclosure. Figure 8 This is a partial cross-sectional view of a laminate 130 according to an embodiment of the present disclosure.

[0099] Reference Figure 7 and Figure 8 The laminate 130 can be configured to be wound around the side surfaces of the stacked electrode assembly 110. In some embodiments, the laminate 130 can be attached to the side surfaces of the MTBs 120a and 120b to at least partially coat the side surfaces of the MTBs 120a and 120b. In some embodiments, a pair of parallel edges 130e of the laminate 130 can coat the entire side surface of the MTBs 120a and 120b parallel to a second direction (e.g., the Y-axis direction). In some other embodiments, the pair of parallel edges 130e of the laminate 130 can coat only a portion of the side surface of the MTBs 120a and 120b parallel to a second direction (e.g., the Y-axis direction).

[0100] The laminate 130 may include a flexible metal layer 134, an inner resin layer 132 disposed on one side of the metal layer 134, and an outer resin layer 136 disposed on the other side of the metal layer 134.

[0101] The metal layer 134 can maintain an appropriate thickness to prevent water vapor, oxygen, and other gases from permeating from the outside to the inside, and to prevent electrolyte leakage. In some embodiments, the metal layer 134 may contain one or more selected from iron (Fe), carbon (C), chromium (Cr), manganese (Mn), nickel (Ni), aluminum (Al), and alloys thereof, but is not limited thereto. If the metal layer 134 is made of a material containing iron, the mechanical strength becomes stronger, and if the metal layer 134 is made of aluminum, the flexibility is improved; therefore, aluminum foil is primarily used.

[0102] The metal layer 134 can be configured to be relatively easily deformed by external force and has appropriate thickness and mechanical strength so that no cracks or holes will appear even under repeated deformation.

[0103] In some embodiments, the metal layer 134 may have a thickness of about 20 micrometers (μm) to about 100 μm. In some embodiments, the thickness of the metal layer 134 may 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.

[0104] The inner resin layer 132 disposed on one side of the metal layer 134 may include a thermally adhesive layer. In some embodiments, the inner resin layer 132 may contain a polyolefin-based material that can perform a sealing action by fusion. In some embodiments, the inner resin layer 132 may contain modified propylene, such as cast polypropylene (CPP) or a polypropylene-butene-ethylene terpolymer.

[0105] The inner resin layer 132 can be formed by coating or laminating it onto one side of the metal layer 134.

[0106] An outer resin layer 136 disposed on the other side of the metal layer 134 can serve as a substrate and protective layer for forming the laminate 130. The outer resin layer 136 may contain an insulating material, such as polyethylene terephthalate (PET) or nylon.

[0107] 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 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.

[0108] In some embodiments, the adhesive resin layer may be further disposed 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 configured for smooth adhesion between dissimilar materials. The adhesive resin layer may be formed as a single layer or multiple layers. In some embodiments, the adhesive resin layer may comprise a polyolefin resin, a polyurethane resin, an epoxy resin, or a mixture thereof.

[0109] In some embodiments, the inner resin layer 132 may be fused to a fused resin layer 122p disposed on the side surfaces of the MTBs 120a and 120b at both ends in a second direction (e.g., the Y-axis direction). Since the inner resin layer 132 surrounds the side surfaces of the MTBs 120a and 120b and is fused to the fused resin layer 122p, the stacked electrode assembly 110 may be encapsulated in the laminate 130.

[0110] The inner resin layer 132 facing the first MTB 120a can be heated and melted while in contact with the fusion resin layer 122p on the side surface of the first MTB 120a to form a first sealing portion 130m1, thereby fusing it to the side surface. The inner resin layer 132 facing the second MTB 120b can be heated and melted while in contact with the fusion resin layer 122p on the side surface of the second MTB 120b to form a second sealing portion 130m2, thereby fusing it to the side surface.

[0111] The end portion 130t of the laminate 130 surrounds the side surfaces of the MTBs 120a and 120b and the stacked electrode assembly 110, and is fused together to form a junction 130m (see reference). Figure 1 Specifically, the laminate 130 can be pressed so that the inner resin layers 132 face each other at the joint 130m, and then the facing inner resin layers 132 can be fused together.

[0112] The joint 130m can be located on either side of the stacked electrode assembly 110. In some embodiments, the joint 130m can be located in a third direction (e.g., the Z-axis direction) surrounding the stacked electrode assembly 110.

[0113] The fusion resin layer 122p may include an extension 122pe extending from the edge portion 130e of the laminate 130 along the side surface of the MTB housing 122. The extension 122pe may extend a predetermined length from the edge portion 130e of the laminate 130 toward the outer end 122oe of the MTB housing 122.

[0114] Figure 9 This is a schematic diagram showing an important portion of the extension 122pe exposed from the edge portion 130e of the laminate 130.

[0115] Reference Figure 9 The thickness d2 of the fused resin layer 122p at a location in the extension 122pe where the thickness is locally increased is greater than the thickness d1 of the fused resin layer 122p at another location in the extension 122pe. For example, the thickness d2 may be about 1.8 times to about 2.2 times the thickness d1.

[0116] Since the extension 122pe is the externally exposed portion of the laminate 130, the laminate 130 can be subjected to little or no thermal shock when it is fused to the MTB housing 122, which has a fusion resin layer 122p between the laminate 130 and the MTB housing. Therefore, in the extension 122pe, the overlapping layer of the polymer film can be retained at a location with a locally increased thickness. In some cases, the overlapping layer of the polymer film may not be observed in the fusion resin layer 122p fused between the laminate 130 and the MTB housing 122.

[0117] Figure 10 This is an illustration along one embodiment of the present disclosure. Figure 7 A cross-sectional view of a significant portion of the first MTB 120a and laminate 130 cut along line X-X'.

[0118] Reference Figure 10 The busbar 125 may be configured to contact the surface of the electrode terminal portion 124. The busbar 125 may be made of a metal material with low resistance. In some embodiments, the busbar 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.

[0119] Busbar 125 can be configured to contact the surface of electrode lead 116 of stacked electrode assembly 110. In some embodiments, busbar 125 can be soldered to electrode lead 116. In some embodiments, busbar 125 can be attached to electrode lead 116 by fasteners such as rivets.

[0120] In some embodiments, the busbar 125 may include a planar central portion 125c extending horizontally in a first direction (e.g., the X-axis direction) and an edge portion 125e that curves and extends from the central portion 125c. The central portion 125c may be configured to form a substantially U-shaped cross-sectional shape together with the edge portion 125e, and may extend in a third direction (e.g., in the Z-axis direction). In some embodiments, the edge portion 125e may have a plane extending perpendicular to the first direction (e.g., in the X-axis direction).

[0121] The busbar 125 can contact the surface of the electrode terminal portion 124 at its center portion 125c. The busbar 125 can contact the surface of the electrode lead 116 at its edge portion 125e.

[0122] In some embodiments, the electrode lead 116 may include a pre-bent portion that bends at the portion that does not contact the busbar 125. The pre-bent portion can prevent stress concentration in a specific portion of the electrode lead 116 by applying an external force to the stacked electrode assembly 110, which can increase safety.

[0123] The laminate 130 can be fused with the fusion resin layer 122p. More specifically, the inner resin layer 132 of the laminate 130 can be fused with the fusion resin layer 122P.

[0124] exist Figure 10 The diagram shows an interface between the inner resin layer 132 and the fused resin layer 122p, but this is only for ease of understanding, and in practice, the interface between the inner resin layer 132 and the fused resin layer 122p may not be identifiable.

[0125] As described above, the extension 122pe of the fusion resin layer 122p may extend more or less from the edge 130e of the laminate 130 toward the outer end 122oe of the side surface of the MTB housing 122.

[0126] (Second Embodiment)

[0127] Figure 11 This is a partially exploded perspective view showing a bonding method of the laminate 130 of a secondary battery 100 according to another embodiment of the present disclosure.

[0128] Reference Figure 11The fusion resin layer 122p may include a protrusion 122pp with a locally increased thickness. In some embodiments, the protrusion 122pp may project in a third-order upward (e.g., in the z-axis direction) as shown in the reference. Figure 4 The length d described.

[0129] In some embodiments, the fusion resin layer 122p may be a polymer ring disposed around the periphery of the MTB housing 122. Since the material of the polymer ring can be the same as previously referenced... Figures 1 to 3 The material of the fusion resin layer 122p described is the same, so further description is omitted in this document.

[0130] The method of forming the protrusion 122pp provided in the fusion resin layer 122p will be described in more detail below. The protrusion 122pp may be, for example, a portion on which tension is applied to the polymer ring when the polymer ring is fused to form the fusion resin layer 122p around the periphery of the MTB housing 122.

[0131] (Third embodiment)

[0132] Figure 12 This is a flowchart illustrating a method for manufacturing a secondary battery 100 according to an embodiment of the present disclosure. Figures 13 to 19 This is a perspective view or side view showing a method of manufacturing a secondary battery 100 according to an embodiment of the present disclosure.

[0133] Reference Figure 12 and Figure 13 MTB 120a, 120b are coupled to both ends of a stacked electrode assembly 110 comprising a plurality of cell batteries 111 stacked in a first direction (e.g., in the X-axis direction) (S110).

[0134] The stacked electrode assembly 110 may have electrode leads at both ends in a second direction (e.g., in the Y-axis direction). This has been referenced. Figure 3 It has been described, and will not be described in detail here.

[0135] In some embodiments, MTBs 120a, 120b and the stacked electrode assembly 110 can be joined together by soldering electrode leads to the busbars of the MTBs. The soldering method is not particularly limited and any suitable method known to those skilled in the art can be used.

[0136] Reference Figure 12 and Figure 14 The fusion resin layer 122p can be formed around the MTB housing 122 of MTB 120a, 120b (S120).

[0137] In some embodiments, the method of forming the fusion resin layer 122p may include wrapping a polymer film around the periphery of the MTB housing 122, as shown in reference 122p. Figure 5 and Figure 9 The polymer films may overlap, but can partially cover the side surfaces of the MTB housing 122. The overlapping portions of the polymer films may have locally increased thickness, and laminates may be fused to these portions, as described below.

[0138] In some embodiments, the method of forming the fusion resin layer 122p may include providing a polymer ring around the periphery of the MTB housing 122 to form its protrusion. Figures 15 to 17 This is a diagram illustrating an embodiment of a method for forming a fusion resin layer 122p.

[0139] Reference Figure 15 The polymer ring 122pr can be disposed around the periphery of the MTB housing 122. The internal length of the polymer ring 122pr is longer than the length of the outer peripheral surface of the MTB housing 122. Therefore, the polymer ring 122pr can be easily disposed around the periphery of the MTB housing 122.

[0140] Now refer to Figure 16 The polymer ring 122pr can be tightly fitted from one side of the MTB housing 122. Figure 16 In the diagram, polymer ring 122pr is shown adhering from the lower portion of MTB housing 122 and extending to the side of MTB housing 122. However, this disclosure is not limited thereto. In some embodiments, polymer ring 122pr may be fused to the surface of MTB housing 122.

[0141] Reference Figure 17 The remaining length of polymer ring 122pr remains on a portion of MTB housing 122. This is because the inner length of polymer ring 122pr is longer than the length of the outer peripheral surface of MTB housing 122. The remaining length portion of polymer ring 122pr can be fused together by bringing the inner surfaces of polymer ring 122pr face each other.

[0142] The remaining length of the polymer rings 122PR that are fused together forms a locally increased thickness of the fused resin layer 122P. Laminated resin 130 may be laminated onto the fused portions of the remaining length of the polymer rings 122PR. In some embodiments, tension may be applied to the polymer rings 122pr as they adhere to the surface of the MTB housing 122. In some embodiments, the location where tension is applied to the polymer rings 122pr may be a portion of the remaining length of the polymer rings 122pr.

[0143] In some embodiments, the remaining length of the polymer ring 122pr may be located at the center of the secondary battery 100 in a first direction (e.g., the X-axis direction); in other words, the remaining length of the polymer ring 122pr may be located at the center of the MTB housing 122 in a first direction (e.g., the X-axis direction).

[0144] Figure 18 It is shown in Figure 16 A diagram of another embodiment of the method for forming the fusion resin layer 122p, which is then performed.

[0145] Reference Figure 18 The remaining length of the polymer ring 122pr can be located near a corner of the MTB housing 122. Those skilled in the art can refer to... Figure 6 The remaining length of the polymer ring 122pr is set.

[0146] Although Figures 12 to 14 The illustration shows MTB 120 being bonded to both ends of a stacked electrode assembly 110, followed by the formation of a fusion resin layer 122p around the periphery of the MTB housing 122; however, this disclosure is not limited thereto. In some other embodiments, after the fusion resin layer 122p is formed around the periphery of the MTB housing 122, the MTB 120 may be bonded to both ends of the stacked electrode assembly 110.

[0147] Reference Figure 12 and Figure 19 The laminate is bonded to the fusion resin layer 122p to be wrapped around the sides of the stacked electrode assembly 110 (S130).

[0148] The laminate 130 may have a pair of substantially parallel edges 130e fused to the outer surface of the MTB 120. On the other hand, a pair of substantially parallel ends 130t connecting the pair of edges 130e of the laminate 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 ends 130t.

[0149] The joint 130m where the two ends 130t are fused together can be configured as a locally thickened portion adjacent to the aforementioned fused resin layer 122p.

[0150] Electrolyte can then be supplied to the stacked electrode assembly 110 through a pair of non-fused portions at the ends 130t (S140).

[0151] In some embodiments, the electrolyte supply step may be performed after the laminate 130 is attached to the MTB 120. In some embodiments, the electrolyte supply step may be performed after the laminate is sealed. In this case, at least one of the MTBs 120 may include an electrolyte injection port.

[0152] The electrolyte can be any conventional electrolyte used in lithium secondary batteries, and is not particularly limited thereto.

[0153] When electrolyte is supplied to the stacked electrode assembly 110 through the unfused portions of a pair of ends 130t, the laminate 130 can then be sealed (S150). Specifically, the laminate 130 can be sealed by stacking the ends 130t together. In some embodiments, the ends 130t can be stacked by applying heat after the inner resin layers 132 of the ends 130t come into contact with each other. In other embodiments, the ends 130t can be stacked by applying heat after the inner resin layer 132 of one end 130t comes into face-to-face contact with the outer resin layer 136 of the other end 130t.

[0154] (Fourth embodiment)

[0155] Figure 20 This is a schematic perspective view of a battery pack 1 according to an embodiment of the present disclosure. Figure 21 It is shown schematically. Figure 20 An exploded perspective view of the configuration of battery pack 1, and Figure 22 It is shown Figure 21 An exploded perspective view of a single battery cell 100 housed in a battery pack housing.

[0156] Reference Figures 20 to 22 According to one embodiment of the present disclosure, the battery pack 1 includes a plurality of battery cells 100, an electrical component assembly 500, a battery pack housing 300, and a battery pack cover 600.

[0157] Battery cells 100 are stacked in a first direction (e.g., along the X-axis), and cooling pads 200 may be inserted between the battery cells. In some embodiments, the stack of battery cells 100 and cooling pads 200 may be stored directly within the battery pack housing 300, rather than within another frame. However, those skilled in the art will understand that various modifications are possible regarding how the battery cells 100 may be stored.

[0158] For example, the stack of battery cell 100 and cooling pad 200 can be stored within a module frame to form a battery module, and the battery module can be stored within a battery pack housing 300. The module frame can be configured as a cubic box that surrounds the periphery of the stack of battery cell 100 and cooling pad 200, allowing the stack of battery cell 100 and cooling pad 200 to be secured from the inside. The module frame can be made of a metallic material with high mechanical rigidity to adequately protect the battery cell 100 from expansion and external impacts.

[0159] Electrical component assembly 500 may include relay devices, current sensors, fuses, battery management systems (BMS), manual service disconnectors (MSDs), etc. Relay devices are switching components that selectively open and close the charging and discharging paths through which current flows, and can stop the flow of charging and discharging current in the event of an abnormality in battery pack 1. BMS refers to a battery management device that provides overall control over the charging and discharging behavior of individual battery cells 100, and may be a component typically included in battery pack 1. MSD refers to a system for selectively disconnecting the power supply to the high-voltage battery by physical means, such as disconnecting the service plug when necessary.

[0160] This electrical component assembly 500, together with the battery cell 100, can be encapsulated by the battery pack housing 300 and the battery pack cover 600 to isolate it from the outside.

[0161] The battery pack housing 300 may be a structure that provides internal storage space for the battery cells 100 and electrical component assemblies 200, and is provided with a bracket 332 or mounting structure 343, 353 for attachment to the main body of the vehicle.

[0162] Since the battery pack housing 300 provides mechanical support to the battery module 100 and the electrical component assembly 500, and is used to protect the battery module and the electrical component assembly from external impacts, the battery pack housing 300 can be made of a high-rigidity metal material.

[0163] The battery pack housing 300 according to this embodiment may include: a lower frame 310, which is arranged in the form of a wide plate, on which battery cells 100 are disposed, a front frame 320, a rear frame 330, a right side frame 340, and a left side frame 350, which are vertically joined along the periphery of the lower frame 310 to form a wall. The battery pack housing 300 may further include a central beam 370 and a set of crossbeams 360 to define the placement space of the battery cells 100. The central beam 370 may have a first end joined to the front frame 320 and a second end joined to the rear frame 330. In some embodiments, the first end of the crossbeams 360 may be joined to the central beam 370, and the other end of the crossbeams 360 may be joined to the right side frame 340 or the left side frame 350. In some embodiments, the crossbeams 360 may extend across the central beam 370, and one end of the crossbeams 360 may be joined to the right side frame 340, and the other end of the crossbeams 360 may be joined to the left side frame 350.

[0164] In some embodiments, the lower frame 310, front frame 320, rear frame 330, right side frame 340, left side frame 350 and crossbeam 360 may each be an extruded aluminum structure and may be formed by welding and / or bolting these frames together to form the battery pack housing 300.

[0165] For example, by extruding aluminum to manufacture the frame, and mixing blank spaces and reinforcing ribs inside the frame, and welding the frame together to form the battery pack housing 300, the weight of the battery pack housing 300 can be reduced, and the mechanical stiffness can be at or above the required reliability level.

[0166] In some embodiments, a heat sink may be further disposed within the battery pack housing 300. The heat sink may be arranged in the form of a plate having a flow path therein to absorb and dissipate heat from another object through thermal contact. In some embodiments, the lower frame 310 may include an inlet port 410a through which coolant can flow in, an outlet port 410b through which coolant can flow out, and cooling channels through which coolant can flow.

[0167] Battery cells 100 can be electrically connected via intermediate busbars 510, 520, and 530. The intermediate busbars may include a first intermediate busbar 510, which is used to electrically connect battery modules 100 arranged in a 2×2 configuration along a first direction (e.g., along the X-axis) and a second direction (e.g., along the Y-axis). In some embodiments, the first intermediate busbar 510 may be located at the intersection of the central beam 370 and the crossbeam 360.

[0168] Additionally, the intermediate busbar may include a second intermediate busbar 520 for electrically connecting the electrically connected battery cell 100 to an external load or charging system. The second intermediate busbar 520 does not need to be directly connected to the external load or charging system, but can be connected to the external load or charging system via the electrical component assembly 500.

[0169] The battery module 100 may include a first group of battery cells 100A located on one side of the central beam 370 and a second group of battery cells 100B located on the other side. The intermediate busbar may include a third intermediate busbar 530 that electrically connects the first group of battery cells 100A and the second group of battery cells 100B.

[0170] As described above, although embodiments of the present disclosure have been described in detail, those skilled in the art will be able to implement the present disclosure with various modifications without departing from the spirit and scope of the present disclosure as defined in the appended claims. Therefore, further modifications to the embodiments of the present disclosure will not depart from the technology of the present disclosure.

[0171] Explanation of reference numerals in the attached figures

[0172] 1: Battery pack

[0173] 100: Secondary battery

[0174] 110: Stacked electrode assembly

[0175] 111: Cell battery

[0176] 116: Electrode leads

[0177] 120, 120a, 120b: MTB

[0178] 122: MTB housing

[0179] 122h: Through hole

[0180] 122p: Fusion resin layer

[0181] 122PE: Extension

[0182] 122pp: Protrusion

[0183] 124: Electrode terminal section

[0184] 125: Busbar

[0185] 128: Check valve

[0186] 130: Laminated sheets

[0187] 130e: Edge

[0188] 130m: Joint

[0189] 130t: End

[0190] 132: Inner resin layer

[0191] 134: Metal layer

[0192] 136: Outer resin layer

Claims

1. A secondary battery, comprising: A stacked electrode assembly in which multiple cell units are stacked in a first direction and the multiple cell units have electrode leads at both ends in a second direction perpendicular to the first direction; A multi-functional terminal block, or MTB, is disposed at both ends of the stacked electrode assembly; as well as A laminate surrounding the side surface of the stacked electrode assembly. The side surface of the MTB includes a fused resin layer with locally increased thickness.

2. The secondary battery according to claim 1, wherein, The bonding portion of the laminate is located at a position where the fused resin layer has a locally increased thickness.

3. The secondary battery according to claim 2, wherein, The fused resin layer is a polymer film, and The location where the fused resin layer has a locally increased thickness has an increased thickness compared to other locations due to the greater number of coatings of the polymer film.

4. The secondary battery according to claim 2, wherein, The fused resin layer includes an extension that extends from the edge of the laminate along the side surface of the MTB.

5. The secondary battery according to claim 4, wherein, The thickness of the fused resin layer at the location in the extension where it has a locally increased thickness is approximately 1.8 to approximately 2.2 times the thickness of the fused resin layer at other locations in the extension.

6. The secondary battery according to claim 2, wherein, The junction is located approximately at the center of the secondary battery in the first direction.

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

8. The secondary battery according to claim 7, wherein, The fused resin layer extends at least partially between the joints.

9. The secondary battery according to claim 8, wherein, The length of the fused resin layer extending between the joints is from about 0.1 mm to about 2 mm.

10. A method for manufacturing a secondary battery, comprising: A multifunctional terminal block, or MTB, is attached to both ends of a stacked electrode assembly, wherein the stacked electrode assembly includes a plurality of cell cells stacked in a first direction and has electrode leads at both ends in a second direction perpendicular to the first direction. A fusion resin layer is formed around the periphery of the MTB housing of the MTB; and The laminate is bonded to the fusion resin layer to surround the side surface of the stacked electrode assembly. The fused resin layer has a locally increased thickness, and The laminate has a bonding portion at the location where the fused 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 fused resin layer includes the step of locally forming an overlapping layer of polymer film.

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

13. The method for manufacturing a secondary battery according to claim 10, wherein, The steps for forming the fusion resin layer include: A polymer ring is provided around the periphery of the MTB housing, wherein the inner length of the polymer ring is longer than the length of the outer peripheral surface of the MTB housing; The polymer ring is fused from one side of the MTB housing onto the side surface of the MTB housing; and The remaining length of the polymer rings is then fused together.

14. The method for manufacturing a secondary battery according to claim 13, wherein, In the step of fusing the remaining length of the polymer rings together, the position where the polymer rings are fused together roughly coincides with the position where the laminate has a bonding portion.

15. The method for manufacturing a secondary battery according to claim 10, wherein, The MTB housing contains electrode terminals electrically connected to the electrode leads of the stacked electrode assembly, and a busbar electrically connecting the electrode leads of the stacked electrode assembly to the electrode terminals. The laminate includes: A flexible metal layer; An inner resin layer, the inner resin layer being disposed on one side of the metal layer; and An outer resin layer is disposed on the other side of the metal layer, and The inner resin layer comprises cast polypropylene, i.e., CPP.

Images