Secondary battery manufacturing method

Abstract

Provided is a secondary battery manufacturing method comprising the steps of: stacking a plurality of unit batteries in a first direction in order to form a stack-type electrode assembly; coupling a multifunctional terminal block (MTB) to both ends of the stack-type electrode assembly that extends in a second direction; attaching a laminate sheet to the MTB so as to encompass the stack-type electrode assembly; injecting an electrolyte into the stack-type electrode assembly; and sealing the laminate sheet in order to form a cell case, wherein the MTB includes: an MTB housing; a bus bar provided in the MTB housing and electrically connected to the stack-type electrode assembly; and an electrode terminal unit exposed to the outside of the MTB housing and electrically connected to the bus bar.

Description

Method for manufacturing secondary batteries

[0001] The present invention relates to a method for manufacturing a secondary battery, and more specifically, to a method for manufacturing a secondary battery capable of manufacturing a high-capacity secondary battery without concern for damage or defects in a pouch.

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0127695, filed September 25, 2023, the entire contents of which are 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 method for manufacturing a secondary battery capable of manufacturing a high-capacity secondary battery without concern for damage or defects in the pouch.

[0006] The present invention provides a method for manufacturing a secondary battery, comprising: a step of stacking a plurality of unit cells in a first direction to form a stacked electrode assembly; a step of connecting a multifunctional terminal block (MTB) to both ends of the stacked electrode assembly extending in a second direction; a step of attaching a laminate sheet to the MTB so as to surround the stacked electrode assembly; a step of injecting an electrolyte into the stacked electrode assembly; and a step of sealing the laminate sheet to form a cell case, wherein the MTB includes: an MTB housing; a bus bar provided within the MTB housing and electrically connected to the stacked electrode assembly; and an electrode terminal portion exposed to the outside of the MTB housing and electrically connected to the bus bar.

[0007] In some embodiments, the stacked electrode assembly may include a first electrode stack including a plurality of unit cells stacked in the first direction and sharing one electrode lead; and a second electrode stack including a plurality of unit cells stacked in the first direction and sharing another electrode lead.

[0008] In some embodiments, the electrode lead to which the first electrode stack is connected and the electrode lead to which the second electrode stack is connected may be connected to a single bus bar.

[0009] In some embodiments, the stacked electrode assembly has three or more electrode stacks, and a thickness of the stacked electrode assembly in the first direction may be greater than a thickness of the MTB housing in the first direction.

[0010] In some embodiments, in the step of attaching a laminate sheet to the MTB, the laminate sheet may be a flat laminate sheet that has not been subjected to a forming process.

[0011] In some embodiments, the laminate sheet may include 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.

[0012] In some embodiments, the step of attaching the laminate sheet to the MTB may include the step of fusing the inner resin layer to the outer side of the MTB housing.

[0013] In some embodiments, the step of injecting the electrolyte may be performed after the step of attaching the laminate sheet to the MTB.

[0014] In some embodiments, in the step of attaching the laminate sheet to the MTB, a pair of parallel edge portions of the laminate sheet may be fused to a side surface of the MTB housing, and a pair of parallel end portions of the laminate sheet may include a portion that is not fused to each other.

[0015] In some embodiments, the step of injecting the electrolyte may be performed through a portion where a pair of parallel end portions of the laminate sheet are not fused to each other.

[0016] In some embodiments, the step of sealing the laminate sheet may include the step of fusing the inner resin layers of the pair of parallel end portions together.

[0017] In some embodiments, the MTB housing may include an inner housing that accommodates the bus bar; and an outer housing that accommodates the inner housing and defines the exterior of the MTB housing.

[0018] In some embodiments, the outer housing includes a metal material, and the electrode terminal portion may be electrically insulated from the outer housing.

[0019] 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 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 a thickness of the stacked electrode assembly in the first direction is greater than a thickness of the MTB in the first direction.

[0020] In some embodiments, the MTB may include a bus bar electrically connected to the stacked electrode assembly; an inner housing that accommodates the bus bar; an outer housing that accommodates the inner housing and defines the exterior of the MTB; and an electrode terminal portion that is exposed to the exterior of the outer housing and electrically connected to the bus bar.

[0021] According to the manufacturing method of the present invention, there is an effect in that a high-capacity secondary battery can be manufactured without concern for damage or defects in the pouch.

[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 flowchart showing a method for manufacturing a secondary battery according to one embodiment of the present invention.

[0024] Figures 2 to 9 are schematic diagrams showing a method for manufacturing a secondary battery according to one embodiment of the present invention.

[0025] Figure 10 is a side view schematically illustrating a secondary battery according to one embodiment of the present invention.

[0026] Figure 11 is an exploded perspective view showing an MTB of a secondary battery according to one embodiment of the present invention.

[0027] 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 intervals depicted in the accompanying drawings.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033]

[0034] (Example 1)

[0035] Fig. 1 is a flowchart illustrating a method for manufacturing a secondary battery (100) according to one embodiment of the present invention. Figs. 2 to 9 are schematic diagrams illustrating a method for manufacturing a secondary battery (100) according to one embodiment of the present invention.

[0036] 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.

[0037] Referring to FIGS. 1 and 2, a plurality of unit cells (111) can be stacked in a first direction (e.g., X-axis direction) to form a stacked electrode assembly (110) (S110).

[0038] Each of the above-described plurality of unit cells (111) may have an electrode material applied to a metal foil that acts as a current collector.

[0039] 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.

[0040] 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.

[0041] The stacked electrode assembly (110) may have electrode tabs (113) at both ends in the second direction (e.g., Y-axis direction). In some embodiments, the electrode tabs (113) may be extensions of metal foil portions of the unit cells (111). In some embodiments, the electrode tabs (113) may be electrically connected to the metal foil portions of the unit cells (111).

[0042] In some embodiments, electrode tabs (113) located on the same side of the unit cells (111) may have the same polarity.

[0043]

[0044] Figure 3 is a schematic diagram showing an electrode lead (116) formed on electrode tabs (113) located on one side of the unit cells (111).

[0045] Referring to FIG. 3, a plurality of electrode tabs (113) may be electrically connected to one electrode lead (116). The electrode lead (116) may be electrically connected to the electrode tabs (113) of the plurality of unit cells (111). One or more electrode tabs (113) may be connected to one electrode lead (116). In some embodiments, two or more electrode tabs may be connected to one electrode lead (116).

[0046] In some embodiments, the plurality of electrode tabs (113) may first be joined to each other by a method such as welding and then connected to the electrode lead (116). In other embodiments, the plurality of electrode tabs (113) may be connected to each other and simultaneously electrically connected to the electrode lead (116).

[0047] The stacked electrode assembly (110) may include a first electrode stack (110a) stacked in the first direction (e.g., X-axis direction) while sharing one electrode lead (116) and a second electrode stack (110b) stacked in the first direction (e.g., X-axis direction) while sharing another electrode lead (116).

[0048] 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) (see FIG. 4) on one side and a second electrode lead (116b) (see FIG. 4) on the other side. In addition, the second electrode stack (110b) included in the stacked electrode assembly (110) may have a third electrode lead (116c) (see FIG. 4) on one side and a fourth electrode lead (116d) (see FIG. 4) on the other side. However, the present invention is not limited thereto.

[0049] 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.

[0050] Referring to FIGS. 1 and 4, a multifunctional terminal block (MTB) (120) can be coupled to both ends of the stacked electrode assembly (110) extending in the second direction (e.g., Y-axis direction) (S120).

[0051] 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).

[0052] Among the electrode leads (116) of the first electrode stack (110a), the first electrode lead (116a) may be connected to the first MTB (120a), and the second electrode lead (116b) may be connected to the second MTB (120b). Among the electrode leads (116) of the second electrode stack (110b), the third electrode lead (116c) may be connected to the first MTB (120a), and the fourth electrode lead (116d) may be connected to the second MTB (120b).

[0053] The second MTB (120b) may have substantially the same configuration as the first MTB (120a), except that the polarity is different. Below, the first MTB (120a) will be described, but those skilled in the art will be able to understand the configuration of the second MTB (120b) from this description.

[0054] The above 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. 5) electrically connecting the electrode terminal portion (124) and the electrode lead (116).

[0055] 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.

[0056] The above MTB housing (122) may include a through hole exposing the electrode terminal portion (124) described below. The through hole may be provided in the MTB housing (122) such that the electrode terminal portion (124) is exposed toward the second direction (e.g., Y-axis direction). Accordingly, the through hole 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 may have an opening that is open in the longitudinal direction of the electrode assembly (110). The shape of the through hole may be configured to match the outer shape of the portion where the electrode terminal portion (124) is exposed to the outside.

[0057] 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, etc., as described later.

[0058] The electrode terminal portion (124) is accommodated within the MTB housing (122) and can be exposed through the through hole. 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.

[0059] 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).

[0060] 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).

[0061] 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.

[0062] 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. Since the check valve (128) does not have a part that is ruptured by the discharge of the gas, it can be restored to its original state after the discharge of the internal gas.

[0063] A bus bar may be further provided within the first MTB (120a). Fig. 5 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).

[0064] Referring to FIG. 5, 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.

[0065] 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.

[0066] Referring to FIGS. 4 and 5, the first electrode lead (116a) of the first electrode stack (110a) and the third electrode lead (116c) of the second electrode stack (110b) may be connected to one bus bar (125). In the same manner, the second electrode lead (116b) of the first electrode stack (110a) and the fourth electrode lead (116d) of the second electrode stack (110b) may be connected to one bus bar (125) provided in the second MTB (120b).

[0067] 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 in a bent manner from the center portion (125c). In some embodiments, 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).

[0068] 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).

[0069] 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.

[0070] Referring to FIGS. 1 and 6, a laminate sheet (130) can be attached to the MTB (120) to surround the stacked electrode assembly (110) (S130).

[0071] The above laminate sheet (130) may be a flat laminate sheet that has not been formed. Here, the fact that the laminate sheet (130) is flat only means that it has not been pre-formed to have a shape for at least partially accommodating the stacked electrode assembly (110), and does not mean that the laminate sheet (130) has no curves.

[0072] Figure 7 is a partial cross-sectional view of the laminate sheet (130) according to one embodiment of the present invention.

[0073] Referring to FIGS. 1, 6, and 7, the laminate sheet (130) may be configured to wrap 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 (120) so as to at least partially cover the side surface of the MTB (120). In some embodiments, the laminate sheet (130) may cover all of the side surfaces of the MTB (120) that are parallel to the second direction (e.g., the Y-axis direction). In other embodiments, the laminate sheet (130) may cover only a portion of the side surfaces of the MTB (120) that are parallel to the second direction (e.g., the Y-axis direction).

[0074] 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).

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] The above inner resin layer (132) can be formed by coating or laminating one side of the above metal layer (134).

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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 (120) at both ends in the second direction (e.g., Y-axis direction). When the laminate sheet (130) surrounds the side surfaces of the MTBs (120), the inner resin layer (132) may be fused to the fusion resin layer (122p), 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 (120) and then cooled, thereby allowing it to be fused onto the side surfaces.

[0084] 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.

[0085] 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.

[0086] The above polyester resin includes polyethylene terephthalate, polybutylene terephthalate, or polyethylene naphthalate, but the present invention is not limited thereto.

[0087] 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.

[0088] The above-mentioned fusion resin layer (122p) may be cast, or may be stretched or rolled in one or two axes.

[0089] 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 of the side surface of the MTB housing (122) toward an outer end of the side surface of the MTB housing (122). 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 and the outer end.

[0090]

[0091] Figure 8 is a perspective view showing the laminate sheet (130) being fused to the side of the MTBs (120).

[0092] Referring to FIGS. 7 and 8, the laminate sheet (130) may have a pair of substantially parallel edge portions (130e) that may be fused to the outer side surfaces of the MTBs (120). Meanwhile, a pair of substantially parallel end portions (130t) connecting the pair of edge portions (130e) of the laminate sheet (130) may not be fused to each other, and a portion of the stacked electrode assembly (110) may be exposed between the pair of end portions (130t).

[0093] In Fig. 8, the pair of terminal parts (130t) are shown as not being fused to each other in their entirety in the longitudinal direction, but the pair of terminal parts (130t) may be fused generally in the longitudinal direction and may remain unfused only for a portion of the length.

[0094] Referring to FIG. 1 and FIG. 8, an electrolyte can be supplied to the stacked electrode assembly (110) through the non-fused portion of the pair of terminal portions (130t) (S140).

[0095] In some embodiments, the step of supplying the electrolyte may be performed after attaching the laminate sheet (130) to the MTBs (120). In some embodiments, the step of supplying the electrolyte may be performed after sealing the laminate sheet. In this case, at least one of the MTBs (120) may include an electrolyte injection port.

[0096] The above electrolyte may be a common electrolyte used for lithium secondary batteries and is not particularly limited.

[0097] Referring to FIGS. 1 and 9, the laminate sheet (130) can be sealed to form a cell case (130c) (S150). The cell case (130c) can define the internal space of the secondary battery (100) together with the MTBs (120).

[0098] In order to seal the laminate sheet (130), the end portions (130t) of the laminate sheet (130) may be fused to each other to form a joint portion (130m). The joint portion (130m) may be formed by fusion of the internal resin layers (132) of the laminate sheet (130). Specifically, the internal resin layer (132) of one end portion (130t) and the internal resin layer (132) of the other end portion (130t) may be fused to each other to form the joint portion (130m). In some embodiments, the fusion may be heat fusion, but the present invention is not limited thereto.

[0099] According to the method for manufacturing a secondary battery (100) described with reference to FIGS. 1 to 9, it is possible to manufacture a secondary battery (100) that accommodates a plurality of electrode stacks because the forming process of the laminate sheet (130) is not performed. When performing a forming process on the laminate sheet to manufacture a secondary battery that accommodates a plurality of electrode stacks, since an excessive step is required, there is a concern that the laminate sheet may be damaged at the step portion and that defects may increase. On the other hand, the method for manufacturing a secondary battery (100) described with reference to FIGS. 1 to 9 does not require the forming process of the laminate sheet (130), so even if a plurality of electrode stacks are accommodated, a large-capacity cell can be implemented without concern of damage to the laminate sheet or defects resulting therefrom.

[0100]

[0101] (Example 2)

[0102] Figure 10 is a side view schematically showing a secondary battery (100) according to one embodiment of the present invention.

[0103] Referring to FIG. 10, the thickness of the stacked electrode assembly (110) in the first direction (e.g., X-axis direction) may be greater than the thickness of the MTB housing (122) in the first direction (e.g., X-axis direction). The stacked electrode assembly (110) may include two, three, four, or more electrode stacks, whereby the thickness in the first direction (e.g., X-axis direction) may proportionally increase. Even if the thickness of the stacked electrode assembly (110) is large, since it is possible to surround it with a laminate sheet (130) without a forming process, concerns about damage to the laminate sheet (130) and defects resulting therefrom may be resolved.

[0104]

[0105] (Example 3)

[0106] Figure 11 is an exploded perspective view showing an MTB (120) of a secondary battery (100) according to one embodiment of the present invention.

[0107] Referring to FIG. 11, the MTB (120) may include an inner housing (122b) that can accommodate a bus bar (125) and an outer housing (122a) that accommodates the inner housing (122b) and defines the exterior of the MTB housing (122).

[0108] In some embodiments, the inner housing (122b) may be formed of an insulator. In some embodiments, the inner housing (122b) may be formed of a polymer resin. In some embodiments, the inner housing (122b) may be formed by injection molding. The inner housing (122b) may include a through hole through which the electrode terminal portion (124) may pass.

[0109] In some embodiments, the outer housing (122a) may include a metal material. In some embodiments, the outer housing (122a) may include a metal such as aluminum, and may be made of, for example, aluminum or an aluminum alloy.

[0110] As described with reference to FIGS. 4 and 5, the outer housing (122a) may have a through-hole through which the electrode terminal portion (124) may pass. In some embodiments, the outer housing (122a) may have through-holes through which a venting disk (126), a check valve (128), etc. may be provided, and the venting disk (126), a check valve (128), etc. may be provided within the through-holes.

[0111] The above outer housing (122a) may be made of an electrical conductor, and in this case, an insulating gasket (129) may be provided for electrical insulation from the electrode terminal portion (124). The insulating gasket (129) may be provided along the inner circumferential surface of the penetration portion through which the electrode terminal portion (124) passes.

[0112] The electrode terminal portion (124) may be configured to make surface contact with the center portion (125c) of the bus bar (125). The electrode terminal portion (124) may be exposed to the outside of the MTB (120) by penetrating the inner housing (122b) and the outer housing (122a) while making surface contact with the bus bar (125).

[0113]

[0114] 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.

[0115]

[0116] [Explanation of symbols]

[0117] 100: Secondary battery

[0118] 110: Stacked electrode assembly

[0119] 110a: First electrode stack

[0120] 110b: Second electrode stack

[0121] 111: Unit battery

[0122] 113: Electrode tab

[0123] 116: Electrode lead

[0124] 120: MTB

[0125] 122: MTB Housing

[0126] 122a: Outer housing

[0127] 122b: Inner housing

[0128] 122p: Fusion resin layer

[0129] 124: Electrode terminal section

[0130] 125: Busbar

[0131] 126: Venting disc

[0132] 128: Check valve

[0133] 129: Insulating gasket

[0134] 130: Laminate sheet

Claims

1. A step of stacking a plurality of unit cells in a first direction to form a stacked electrode assembly; A step of connecting a multifunctional terminal block (MTB) to both ends of the stacked electrode assembly extending in the second direction; A step of attaching a laminate sheet to the MTB to surround the stacked electrode assembly; A step of injecting an electrolyte into the stacked electrode assembly; and A step of sealing the laminate sheet to form a cell case; Including, The above MTB: MTB housing; a bus bar provided within the MTB housing and electrically connected to the stacked electrode assembly; and An electrode terminal portion exposed to the outside of the above MTB housing and electrically connected to the above bus bar; A method for manufacturing a secondary battery including:

2. In paragraph 1, The above stacked electrode assembly: A first electrode stack including a plurality of unit cells stacked in the first direction and sharing one electrode lead; and A second electrode stack comprising a plurality of unit cells stacked in the first direction, sharing another electrode lead; A method for manufacturing a secondary battery, characterized in that it includes:

3. In paragraph 2, A method for manufacturing a secondary battery, characterized in that the electrode lead to which the first electrode stack is connected and the electrode lead to which the second electrode stack is connected are connected to one bus bar.

4. In paragraph 2, A method for manufacturing a secondary battery, wherein the stacked electrode assembly has three or more electrode stacks, and a thickness of the stacked electrode assembly in a first direction is greater than a thickness of the MTB housing in the first direction.

5. In paragraph 1, A method for manufacturing a secondary battery, characterized in that in the step of attaching a laminate sheet to the above MTB, the laminate sheet is a flat laminate sheet that has not been subjected to forming treatment.

6. In paragraph 1, 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; A method for manufacturing a secondary battery, characterized in that it includes:

7. In paragraph 6, A method for manufacturing a secondary battery, characterized in that the step of attaching a laminate sheet to the MTB includes a step of fusing the inner resin layer to the outer side of the MTB housing.

8. In paragraph 6, A method for manufacturing a secondary battery, characterized in that the step of injecting the electrolyte is performed after the step of attaching a laminate sheet to the MTB.

9. In paragraph 8, A method for manufacturing a secondary battery, characterized in that, in the step of attaching a laminate sheet to the MTB, a pair of parallel edge portions of the laminate sheet are fused to a side surface of the MTB housing, and a pair of parallel end portions of the laminate sheet include a portion that is not fused to each other.

10. In paragraph 9, A method for manufacturing a secondary battery, characterized in that the step of injecting the electrolyte is performed through a portion where a pair of parallel end portions of the laminate sheet are not fused to each other.

11. In paragraph 9, A method for manufacturing a secondary battery, characterized in that the step of sealing the laminate sheet includes a step of fusing the inner resin layers of the pair of parallel end portions.

12. In paragraph 1, The above MTB housing: an inner housing accommodating the above bus bar; and An outer housing that accommodates the inner housing and defines the appearance of the MTB housing; A method for manufacturing a secondary battery, characterized in that it includes:

13. In paragraph 12, The above outer housing comprises a metal material, A method for manufacturing a secondary battery, characterized in that the electrode terminal portion is electrically insulated from the outer housing.

14. 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; Includes, A secondary battery, characterized in that the thickness of the stacked electrode assembly in the first direction is greater than the thickness of the MTB in the first direction.

15. In paragraph 14, The above MTB: A bus bar electrically connected to the above stacked electrode assembly; An inner housing that accommodates the above bus bar; An outer housing that accommodates the inner housing and defines the exterior of the MTB; and An electrode terminal portion exposed to the outside of the outer housing and electrically connected to the bus bar; A secondary battery characterized by including:

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