Secondary batteries

Abstract

Provided is a secondary battery including: a stacked electrode assembly in which a plurality of unit batteries are stacked in a first direction, with electrode tabs of the plurality of unit batteries at both side ends in a second direction perpendicular to the first direction; multifunctional terminal blocks (MTBs) provided at both side ends of the stacked electrode assembly; and a laminate sheet wrapping a side surface of the stacked electrode assembly, wherein the MTB includes a busbar structure electrically connected to the electrode tabs and an MTB housing that accommodates the busbar structure, and the busbar structure includes a first busbar plate into which the plurality of electrode tabs are inserted and a second busbar plate in surface contact with the first busbar plate.

Description

[Technical Field]

[0001] The present invention relates to a secondary battery, and more particularly to a secondary battery having a bus bar structure that can connect a large number of electrode tabs simply and reliably.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0170392, filed November 30, 2023, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference. [Background technology]

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

[0004] Meanwhile, in recent years, there has been an increasing demand for large-capacity battery packs that are used in electric vehicles, etc. Large-capacity battery packs installed in automobiles are required to have not only larger capacity but also improved safety. Summary of the Invention [Problem to be solved by the invention]

[0005] A technical problem to be solved by the present invention is to provide a secondary battery having a bus bar structure that can connect a large number of electrode tabs simply and reliably. [Means for solving the problem]

[0006] In order to achieve the above technical objectives, the present invention provides a secondary battery including: a stacked electrode assembly in which a plurality of unit batteries are stacked in a first direction, with electrode tabs of the plurality of unit batteries at both side ends in a second direction perpendicular to the first direction; multifunctional terminal blocks (MTBs) provided at both side ends of the stacked electrode assembly; and a laminate sheet wrapping a side surface of the stacked electrode assembly, wherein the MTB includes a busbar structure electrically connected to the electrode tabs and an MTB housing that accommodates the busbar structure, and the busbar structure includes a first busbar plate into which the plurality of electrode tabs are inserted, and a second busbar plate in surface contact with the first busbar plate.

[0007] In some embodiments, the first bus bar plate includes two or more slits, and a plurality of electrode tabs can be inserted into each slit.

[0008] In some embodiments, the stacked electrode assembly includes two or more electrode groups, and an electrode tab included in one electrode group can be inserted into one slit.

[0009] In some embodiments, the second bus bar plate may be in surface contact with the first bus bar plate with the ends of the plurality of electrode tabs therebetween.

[0010] In some embodiments, the second bus bar plate may include a first portion that is in surface contact with the first bus bar plate, and a second portion that extends from the first portion and is bent.

[0011] In some embodiments, the second portion may be electrically connected to an electrode terminal portion of the MTB.

[0012] In some embodiments, the second portion can be folded 180 degrees and extend from the first portion.

[0013] In some embodiments, the first bus bar plate and the second bus bar plate may be area welded.

[0014] In some embodiments, the first busbar plate and the second busbar plate may be joined by an electromagnetic pulse technique (EMPT).

[0015] Another aspect of the present invention provides a secondary battery including: a stacked electrode assembly in which a plurality of unit batteries are stacked in a first direction, the plurality of unit batteries having electrode tabs at both side ends in a second direction perpendicular to the first direction; multifunctional terminal blocks (MTBs) provided at both side ends of the stacked electrode assembly; and a laminate sheet wrapping a side surface of the stacked electrode assembly, the MTB including a busbar structure electrically connecting the electrode tabs and an MTB housing accommodating the busbar structure, the busbar structure including a first busbar plate and a second busbar plate in surface contact with each other, the second busbar plate including a first portion in surface contact with the first busbar plate and a second portion extending from the first portion and bent.

[0016] In some embodiments, the first portion may include a plurality of slits into which electrode tabs can be inserted, and a plurality of electrode tabs may be inserted into each of the plurality of slits.

[0017] In some embodiments, the plurality of electrode tabs may extend between the first bus bar plate and the second bus bar plate.

[0018] In some embodiments, the plurality of electrode tabs may be integrated between the first bus bar plate and the second bus bar plate such that an interface with at least one of the first bus bar plate and the second bus bar plate is not identified.

[0019] In some embodiments, the second portion may be folded 180 degrees and extend from the first portion.

[0020] In some embodiments, the first busbar plate and the first portion of the second busbar plate may be joined by an electromagnetic pulse technique (EMPT). [Effects of the Invention]

[0021] The secondary battery of the present invention has the advantage that a large number of electrode tabs can be connected to the bus bar structure simply and reliably.

[0022] The effects that can be obtained from the exemplary embodiments of the present disclosure are not limited to the effects described above, and other effects not mentioned will be clearly derived and understood by a person having ordinary skill in the art to which the exemplary embodiments of the present disclosure pertain from the following description. In other words, unintended effects accompanying the implementation of the exemplary embodiments of the present disclosure can also be derived from the exemplary embodiments of the present disclosure by a person having ordinary skill in the art. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a perspective view showing a main part of a secondary battery according to one embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged partial perspective view of a part of the secondary battery of FIG. [Figure 3] FIG. 3 is a schematic perspective view showing the secondary battery of FIG. 1 with the laminate sheet removed. [Figure 4] FIG. 4 is an exploded perspective view showing an end portion of a secondary battery according to one embodiment of the present invention. [Figure 5] FIG. 5 is a schematic diagram showing a cross section of the end of the secondary battery shown in FIG. 4 taken along the line passing through the electrode terminal portion. [Figure 6]FIG. 6 is a conceptual diagram showing a method for coupling a plurality of electrode tabs to the first bus bar plate and the second bus bar plate. [Figure 7] FIG. 7 is a conceptual diagram showing how a plurality of electrode tabs are integrated when the first bus bar plate and the second bus bar plate are joined together. [Figure 8] FIG. 8 is a conceptual diagram showing how a plurality of electrode tabs are integrated when the first bus bar plate and the second bus bar plate are joined together. [Figure 9] FIG. 9 is a conceptual diagram showing how a plurality of electrode tabs are integrated when the first bus bar plate and the second bus bar plate are joined together. [Figure 10] FIG. 10 is a schematic side view showing a main part of an end portion of a secondary battery according to one embodiment of the present invention. [Figure 11] FIG. 11 is a partially exploded perspective view showing a joining method of laminate sheets of a secondary battery according to one embodiment of the present invention. [Figure 12] FIG. 12 is a partial cross-sectional view of a laminate sheet according to one embodiment of the present invention. [Figure 13] FIG. 13 is a schematic perspective view of a battery pack according to one embodiment of the present invention. [Figure 14] FIG. 14 is an exploded perspective view schematically showing the configuration of the battery pack of FIG. [Figure 15] FIG. 15 is a perspective view showing the battery cell of FIG. 14 seated in a pack housing. [Figure 16] FIG. 16 is an exploded perspective view showing an end portion of a secondary battery according to another embodiment of the present invention. [Figure 17] FIG. 17 is a schematic diagram showing a cross section of the end of the secondary battery shown in FIG. 16 taken along the line passing through the electrode terminal portion. DETAILED DESCRIPTION OF THE INVENTION

[0024] Preferred embodiments of the inventive concept will now be described in detail with reference to the accompanying drawings. However, the embodiments of the inventive concept can be modified into various different forms, and the scope of the inventive concept should not be construed as being limited by the embodiments described below. The embodiments of the inventive concept are preferably construed as being provided to more completely explain the inventive concept to those with average knowledge in the art. The same reference numerals refer to the same elements throughout. Furthermore, various elements and regions in the drawings are drawn schematically. Therefore, the inventive concept is not limited by the relative sizes or spacings depicted in the accompanying drawings.

[0025] Terms such as "first," "second," etc. may be used to describe various components, but the components are not limited by these terms. These terms are used only to distinguish one component from another. For example, a first component may be designated a "second component," and vice versa, without departing from the scope of the inventive concept.

[0026] The terms used in this application are merely used to describe specific embodiments and are not intended to limit the concept of the present invention. A singular expression includes a plural expression unless the context clearly indicates otherwise. In this application, expressions such as "comprise" or "have" are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, and are understood not to preclude the presence or possibility of addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0027] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the concept of the present invention belongs. Furthermore, terms defined in commonly used dictionaries can be interpreted to have a meaning consistent with what they mean in the context of the relevant art, and unless explicitly defined herein, they should not be interpreted as overly formal.

[0028] In other embodiments, the order of certain steps may be different from that described, for example, two steps described as successive may be performed substantially simultaneously or may be performed in the reverse order from that described.

[0029] In the accompanying drawings, variations in the shapes shown may be expected due, for example, to manufacturing techniques and / or tolerances. Therefore, embodiments of the present invention should not be construed as limited to the specific shapes of regions shown herein and may include, for example, variations in shapes resulting from the manufacturing process. As used herein, the term "and / or" includes each and every combination of one or more of the referenced elements. Furthermore, the term "substrate" as used herein may refer to the substrate itself or a laminated structure including the substrate and a predetermined layer or film formed on its surface. Furthermore, as used herein, the term "surface of the substrate" may refer to the exposed surface of the substrate itself or the outer surface of a predetermined layer or film formed on the substrate.

[0030] (First embodiment) Fig. 1 is a perspective view showing a main part of a secondary battery 100 according to one embodiment of the present invention. Fig. 2 is a partial perspective view showing an enlarged view of a part of the secondary battery 100 of Fig. 1. Fig. 3 is a schematic perspective view showing a state in which a laminate sheet 130 has been removed from the secondary battery 100 of Fig. 1.

[0031] In the following drawings, the secondary battery 100 is shown as being defined in a vertical coordinate system defined by a first direction along the X axis, a second direction along the Y axis, and a third direction along the Z axis, which are perpendicular to each other; however, the first direction, second direction, and third direction may be perpendicular to each other, and are not particularly limited.

[0032] Referring to FIGS. 1 to 3, a secondary battery 100 includes a stacked electrode assembly 110, multifunctional terminal blocks (MTB) 120a and 120b, and a laminate sheet .

[0033] The stacked electrode assembly 110 may include a plurality of unit cells 111 stacked in a first direction (e.g., the X-axis direction). Each of the unit cells 111 may be formed by coating an electrode material on a metal foil that acts as a current collector.

[0034] Each unit battery 111 may have a thin plate-like body extending in a second direction (e.g., the Y-axis direction). Each unit battery 111 may be a positive electrode unit battery or a negative electrode unit battery. In some embodiments, the plurality of unit batteries 111 may be formed by stacking positive electrode unit batteries and negative electrode unit batteries one by one alternately. These positive electrode unit batteries and negative electrode unit batteries may be separated from each other by a separator.

[0035] In some other embodiments, the plurality of unit batteries 111 may be formed by stacking a plurality of positive electrode unit batteries and a plurality of negative electrode unit batteries alternately. The plurality of positive electrode unit batteries and the plurality of negative electrode unit batteries may be separated from each other by a separator.

[0036] The stacked electrode assembly 110 may have electrode tabs 116 at both ends in the second direction (e.g., the Y-axis direction). The electrode tabs 116 may be extensions of uncoated portions of current collectors of the plurality of unit cells 111.

[0037] The stacked electrode assembly 110 may include a first electrode group 110a and a second electrode group 110b stacked in a first direction (e.g., the X-axis direction). The unit batteries 111 of the first electrode group 110a may be stacked in the first direction (e.g., the X-axis direction), and the electrode tabs 116 of the unit batteries 111 on both sides may be interleaved with each other. Also, the unit batteries 111 of the second electrode group 110b may be stacked in the first direction (e.g., the X-axis direction), and the electrode tabs 116 of the unit batteries 111 on both sides may be interleaved with each other.

[0038] In some embodiments, the first electrode group 110a may have a first electrode tab 116a laminated on one side with a predetermined polarity and a second electrode tab 116b laminated on the other side with a different polarity, and the second electrode group 110b may have a third electrode tab 116c laminated on one side with a predetermined polarity and a fourth electrode tab 116d laminated on the other side with a different polarity.

[0039] A first MTB 120a may be provided 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 provided at the other end. One of the first MTB 120a and the second MTB 120b may be electrically connected to the positive electrode side of the stacked electrode assembly 110, and the other may be electrically connected to the negative electrode side of the stacked electrode assembly 110. The second MTB 120b may have substantially the same configuration as the first MTB 120a, except for the polarity. The first MTB 120a will be described below, and those skilled in the art will be able to understand the configuration of the second MTB 120b from this description.

[0040] In some embodiments, the first MTB 120a may include an MTB housing 122, an electrode terminal portion 124 housed within the MTB housing 122, and a busbar structure 125 (see FIG. 4) that electrically connects the electrode terminal portion 124 to the laminated electrode tab 116.

[0041] The MTB housing 122 may comprise a relatively rigid material, such as a metal, and defines the exterior of the first MTB 120a. In some embodiments, the MTB housing 122 may be made of aluminum (Al), nickel (Ni), iron (Fe), cobalt (Co), chromium (Cr), manganese (Mn), or an alloy containing one or more of these.

[0042] The MTB housing 122 may include a through-hole 122h that exposes the electrode terminal portion 124, which will be described later. The through-hole 122h may be provided in the MTB housing 122 so that the electrode terminal portion 124 is exposed in 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 is open in the longitudinal direction of the electrode assembly 110. The shape of the through-hole 122h may be configured to match the outer edge shape of the portion of the electrode terminal portion 124 that is exposed to the outside.

[0043] In some embodiments, the exposed surface of the electrode terminal portion 124 from the MTB housing 122 toward the outside may be flat. In some embodiments, the exposed surface may have a plane extending perpendicular to the second direction (e.g., the Y-axis direction). In some embodiments, the electrode terminal portion 124 may have a disk-shaped free surface exposed to the outside.

[0044] In some embodiments, an electrically insulating insulating gasket 129 can be provided between the electrode terminal 124 and the MTB housing 122 so that the electrode terminal 124 is electrically insulated from the MTB housing 122 .

[0045] In some embodiments, the first MTB 120a may include a venting disk configured to rupture when the internal pressure of the secondary battery 100 increases excessively, thereby discharging gas that causes the excessively increased internal pressure. If the venting disk ruptures due to a thermal event occurring inside the secondary battery 100, the venting disk does not return to its original state. The venting disk may be any venting disk known in the art and is not particularly limited.

[0046] In some embodiments, the MTB housing 122 may further include a fusion resin layer 122p on the side surface.

[0047] The fusion resin layer 122p is a layer of thermoplastic resin, and may contain, for example, one or more of polyolefin resin, polyester resin, polyamide resin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyacrylonitrile, polyurethane, polycarbonate, polyacetal, polyacrylate, and modified polyvinyl alcohol resin.

[0048] Examples of the polyolefin resin include polyethylene, polypropylene, poly(1-butene), poly(4-methyl-1-pentene), ethylene-propylene copolymer, copolymer of ethylene and an α-olefin having 4 or more carbon atoms, copolymer of polyolefin and maleic anhydride, ethylene-vinyl ester copolymer, ethylene-acrylic acid ester copolymer, or modified polyolefin obtained by graft-modifying any of these with an unsaturated carboxylic acid or a derivative thereof, but the present invention is not limited thereto.

[0049] The polyester resin may include, but is not limited to, polyethylene terephthalate, polybutylene terephthalate, or polyethylene naphthalate.

[0050] The polyamide resin includes, but is not limited to, nylon 6, nylon 6·6, nylon 6 / 66 copolymer, nylon 11, nylon 12, or poly(m-xylene adipamide).

[0051] The fusion resin layer 122p may be unstretched (cast), or may be uniaxially or biaxially stretched or rolled.

[0052] In some embodiments, the fusion resin layer 122p may at least partially cover the side surface of the MTB housing 122. In some embodiments, the fusion resin layer 122p may extend from an inner end 122ie of the side surface of the MTB housing 122 to an outer end 122oe of the side surface of the MTB housing 122. Here, the inner end 122ie refers to the end adjacent to the electrode tab 116. In some embodiments, the fusion resin layer 122p may surround the side surface of the MTB housing 122 while having a predetermined width between the inner end 122ie and the outer end 122oe. In some embodiments, the fusion resin layer 122p may extend along the side surface of the MTB housing 122 while having a predetermined width between the inner end 122ie and the outer end 122oe.

[0053] In some embodiments, the fusion resin layer 122p may have a constant width between the inner end 122ie and the outer end 122oe and may surround the side surface of the MTB housing 122. In some embodiments, the fusion resin layer 122p may have a constant width between the inner end 122ie and the outer end 122oe and may extend in a first direction (e.g., the X-axis direction) and / or a third direction (e.g., the Z-axis direction).

[0054] In some embodiments, the fusion resin layer 122p may extend along the side of the MTB housing 122 while having a constant width between the inner end 122ie and the outer end 122oe.

[0055] In some embodiments, the fusion resin layer 122p can cover the entire side surface of the MTB housing 122.

[0056] The fusion resin layer 122p can have a thickness of, for example, about 20 μm to about 400 μm. In some embodiments, the fusion resin layer 122p can 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.

[0057] If the thickness of the fusion resin layer 122p is too thin, the mechanical strength may be insufficient, whereas if the thickness of the fusion resin layer 122p is too thick, it may be economically disadvantageous.

[0058] The fusion resin layer 122p may be fused to the laminate sheet 130. In some embodiments, the fusion resin layer 122p may extend from the end 130e of the laminate sheet 130. In some embodiments, the fusion resin layer 122p may extend toward the outer end 122oe after being exposed from the edge portion 130e of the laminate sheet 130.

[0059] In some embodiments, the first MTB 120a may further include a check valve 128. The check valve 128 may be configured to open to discharge internal gas when the internal pressure of the secondary battery 100 exceeds a predetermined pressure, and to close again when the internal pressure is relieved by discharging the gas. The check valve 128 does not have any parts that may burst due to the discharge of the gas, and may be restored to its original state after the internal gas is discharged.

[0060] Secondary battery 100 further includes an electrolyte. The electrolyte may be any electrolyte used for a typical lithium secondary battery, and is not particularly limited. In some embodiments, the electrolyte may be injected just before sealing laminate sheet 130. In some embodiments, the electrolyte may be injected through an electrolyte injection port provided in first MTB 120a after sealing laminate sheet 130.

[0061] FIG. 4 is an exploded perspective view showing an end portion of a secondary battery 100 according to one embodiment of the present invention.

[0062] Referring to FIG. 4, the first MTB 120a includes an MTB housing 122, a bus bar structure 125 housed inside the MTB housing 122, and an electrode terminal portion 124 electrically connected to the bus bar structure 125.

[0063] The busbar structure 125 may be electrically connected to the electrode tabs 116a and 116c of the stacked electrode assembly 110. The busbar structure 125 may electrically connect the electrode tabs 116a and 116c and the electrode terminal portion 124.

[0064] The busbar structure 125 may include a first busbar plate 1251 and a second busbar plate 1252. The first busbar plate 1251 and the second busbar plate 1252 are electrically coupled to each other. In some embodiments, the first busbar plate 1251 and the second busbar plate 1252 may be area welded to each other.

[0065] In some embodiments, the first busbar plate 1251 and the second busbar plate 1252 may each independently 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.

[0066] In some embodiments, the first bus bar plate 1251 may be a substantially flat plate. The first bus bar plate 1251 may include slits 1251s through which the electrode tabs 116a and 116c can pass. The first electrode tab 116a may have one corresponding slit 1251s. The third electrode tab 116c may also have one corresponding slit 1251s. Those skilled in the art will appreciate that the second electrode tab 116b and the fourth electrode tab 116d may also have corresponding slits in the first bus bar plate housed within the second MTB 120b.

[0067] Specifically, the first electrode tabs 116a are provided on one side of the unit batteries belonging to the first electrode group 110a and are inserted into one slit 1251s. The third electrode tabs 116c are provided on one side of the unit batteries belonging to the second electrode group 110b and are inserted into another slit 1251s. That is, the electrode tabs 116a and 116c included in one electrode group 110a and 110b can be inserted into one slit 1251s.

[0068] The second bus bar plate 1252 may include a first portion 1252a configured to be in area contact with the first bus bar plate 1251. The second bus bar plate 1252 may also include a second portion 1252b electrically connected to the first portion 1252a and bent and extending from the first portion 1252a. In some embodiments, the second portion 1252b may be bent 180 degrees and extending from the first portion 1252a. The second portion 1252b may be electrically connected to the electrode terminal portion 124.

[0069] In some embodiments, the first portion 1252a of the second bus bar plate 1252 can extend substantially parallel to the second portion 1252b, and the first portion 1252a and the second portion 1252b can be two opposite portions of a folded flat plate.

[0070] The busbar structure 125 may be housed within the MTB housing 122. The busbar structure 125 may be electrically coupled to the electrode terminal portion 124 extending through the through-hole 122h of the MTB housing 122. In some embodiments, the busbar structure 125 may be configured to be in direct contact with the electrode terminal portion 124. In some embodiments, the electrode terminal portion 124 may be configured to be in direct contact with the second busbar plate 1252 of the busbar structure 125. In some embodiments, the electrode terminal portion 124 may be configured to be in direct contact with the second portion 1252b of the second busbar plate 1252.

[0071] The above describes the first MTB 120a, but those skilled in the art will understand from the above that the second MTB 120b located on the opposite side of the first MTB 120a can also be configured in the same manner.

[0072] FIG. 5 is a schematic diagram showing a cross section of the end of the secondary battery 100 shown in FIG. 4 taken along the line passing through the electrode terminal portion 124. As shown in FIG.

[0073] 5, the plurality of electrode tabs 116a, 116c may extend between the first bus bar plate 1251 and the second bus bar plate 1252. In some embodiments, the plurality of electrode tabs 116a, 116c may extend along the interface between the first bus bar plate 1251 and the second bus bar plate 1252 after passing through the slits 1251s in the first bus bar plate 1251. In some embodiments, the plurality of electrode tabs 116a, 116c may extend in a first direction (e.g., the X-axis direction) between the first bus bar plate 1251 and the second bus bar plate 1252.

[0074] 5, the ends of the electrode tabs 116a, 116c have two sides that extend parallel to each other. In some embodiments, one side of the ends of the electrode tabs 116a, 116c may contact the first bus bar plate 1251 and extend in a first direction (e.g., the X-axis direction). In some embodiments, the other side of the ends of the electrode tabs 116a, 116c may contact the second bus bar plate 1252 and extend in the first direction (e.g., the X-axis direction).

[0075] In some embodiments, the electrode tabs 116a, 116c may include shock absorbing portions that are bent in a predetermined direction in the portions that are not inserted into the slits 1251s.

[0076] FIG. 6 is a conceptual diagram showing a method for coupling a plurality of electrode tabs 116a to a first bus bar plate 1251 and a second bus bar plate 1252. As shown in FIG.

[0077] 6, the electrode tabs 116a may be passed through slits 1251s formed in the first bus bar plate 1251. Then, the ends of the electrode tabs 116a may be bent toward one side. In this case, the ends of the electrode tabs 116a may not be tightly attached to the first bus bar plate 1251.

[0078] Next, the second busbar plate 1252 can be brought into contact with the first busbar plate 1251 and then area welded. In other words, the first busbar plate 1251 and the second busbar plate 1252 can be area welded together with the ends of the plurality of electrode tabs 116a interposed between the first busbar plate 1251 and the second busbar plate 1252. In some embodiments, the welding between the first busbar plate 1251 and the second busbar plate 1252 can be cold welding.

[0079] Area welding can be achieved by, for example, explosion welding, pressure welding, electromagnetic pulse technique (EMPT), etc. In some embodiments, the second busbar plate 1252 can be joined to the first busbar plate 1251 by EMPT. When EMPT is used to join the first busbar plate 1251 and the second busbar plate 1252, a strong electrical repulsive force (see arrow direction) can be applied to the second busbar plate 1252 while the first busbar plate 1251 is fixed.

[0080] Area welding allows the second bus bar plate 1252 to be joined to the first bus bar plate 1251 over a predetermined area, resulting in stronger joining strength compared to joining methods that join only along a specific line or at specific points. In particular, the EMPT method can join the first bus bar plate 1251 and the second bus bar plate 1252 with high reliability and high speed.

[0081] By joining the first busbar plate 1251 and the second busbar plate 1252, the ends of the electrode tabs 116a come into close contact with the first busbar plate 1251 and / or the second busbar plate 1252. In some embodiments, the ends of the electrode tabs 116a can be integral with the first busbar plate 1251. In some embodiments, the ends of the electrode tabs 116a can be integral with the second busbar plate 1252.

[0082] In the past, to electrically connect multiple electrode tabs to a bus bar, the multiple electrode tabs had to be first welded to each other and then welded to an electrode lead. However, in embodiments of the present invention, not only is the electrode lead unnecessary, but the multiple electrode tabs belonging to each electrode group are inserted into a bus bar structure and then welded together at once, thereby significantly simplifying the manufacturing process. Furthermore, because the electrode tabs are area-welded by cold welding, they can be joined to the bus bar structure with high reliability and joint strength, and defects due to welding burn can be prevented.

[0083] 7 to 9 are conceptual diagrams showing how a plurality of electrode tabs 116 are integrated when first bus bar plate 1251 and second bus bar plate 1252 are joined together.

[0084] Referring to FIG. 7 , the first busbar plate 1251 and the second busbar plate 1252 may be joined together to be in close contact with each other. The electrode tabs 116 may extend between the first busbar plate 1251 and the second busbar plate 1252 after passing through the slits in the first busbar plate 1251. The electrode tabs 116 may be integrated with the second busbar plate 1252 by joining the first busbar plate 1251 and the second busbar plate 1252. In some embodiments, the electrode tabs 116 may be integrated such that the interface with the second busbar plate 1252 is unclear. In FIG. 7 , the dotted line between the electrode tabs 116 and the second busbar plate 1252 conceptually indicates the interface before complete joining.

[0085] In some embodiments, an interface may be observed between the plurality of electrode tabs 116 and the first bus bar plate 1251. However, even if such an interface is observed, the plurality of electrode tabs 116 and the first bus bar plate 1251 are in very close contact with each other, so sufficient bonding strength and electrical conductivity may be ensured.

[0086] Although FIG. 7 shows an interface between the first bus bar plate 1251 and the second bus bar plate 1252, a person skilled in the art will understand that depending on the area welding method and conditions, an interface between the first bus bar plate 1251 and the second bus bar plate 1252 may not be visible.

[0087] 8, by joining the first bus bar plate 1251 and the second bus bar plate 1252, the plurality of electrode tabs 116 may be integrated with the first bus bar plate 1251. In some embodiments, the plurality of electrode tabs 116 may be integrated such that the interface with the first bus bar plate 1251 is unclear. In FIG. 8, the dotted line between the plurality of electrode tabs 116 and the first bus bar plate 1252 conceptually indicates the interface before complete joining.

[0088] In some embodiments, an interface may be observed between the plurality of electrode tabs 116 and the second bus bar plate 1252. However, even if an interface is observed, the plurality of electrode tabs 116 and the second bus bar plate 1252 are in very close contact with each other, so sufficient bonding strength and electrical conductivity may be ensured.

[0089] Although FIG. 8 shows an interface between the first bus bar plate 1251 and the second bus bar plate 1252, a person skilled in the art will understand that depending on the area welding method and conditions, an interface between the first bus bar plate 1251 and the second bus bar plate 1252 may not be visible.

[0090] 9 , the first bus bar plate 1251 and the second bus bar plate 1252 are joined together, so that the electrode tabs 116 are integrated with the first bus bar plate 1251 and the second bus bar plate 1252. In some embodiments, the electrode tabs 116 may be integrated such that the interface between the first bus bar plate 1251 and the second bus bar plate 1252 is unclear.

[0091] Although FIG. 9 shows an interface between the first bus bar plate 1251 and the second bus bar plate 1252, a person skilled in the art will understand that depending on the area welding method and conditions, an interface may not be visible between the first bus bar plate 1251 and the second bus bar plate 1252.

[0092] FIG. 10 is a schematic side view showing a main part of an end portion of a secondary battery 100 according to one embodiment of the present invention.

[0093] 10, a busbar structure 125 is housed in the MTB housing 122, and the busbar structure 125 may be electrically connected to the electrode terminal portion 124. The overlapping electrode tabs 116 may pass through slits in the first busbar plate 1251 and then extend in a first direction (e.g., the X-axis direction) between the first busbar plate 1251 and the second busbar plate 1252.

[0094] The first portion 1252a of the second bus bar plate 1252 may be in surface contact with the first bus bar plate 1251. The second portion 1252b of the second bus bar plate 1252 may extend from the first portion 1252a of the second bus bar plate 1252 and be bent 180 degrees. The second portion 1252b may be electrically connected to the electrode terminal portion 124. In some embodiments, the second portion 1252b may be in direct contact with the electrode terminal portion 124. In some embodiments, the second portion 1252b may be electrically connected to the electrode terminal portion 124 via another conductor.

[0095] In some embodiments, the first bus bar plate 1251 and the second bus bar plate 1252 can be electrically isolated from the MTB housing 122.

[0096] Although FIG. 10 shows an example in which the second bus bar plate 1252 is bent 180 degrees about the X axis, a person skilled in the art will understand that the second bus bar plate 1252 may also be bent 180 degrees about the Z axis.

[0097] Fig. 11 is a partially exploded perspective view showing a joining method of the laminate sheet 130 of the secondary battery 100 according to one embodiment of the present invention. Fig. 12 is a partial cross-sectional view of the laminate sheet 130 according to one embodiment of the present invention.

[0098] 11 and 12, the laminate sheet 130 can be configured to wrap around the side surfaces of the stacked electrode assembly 110. In some embodiments, the laminate sheet 130 can be attached to the side surfaces of the MTBs 120a and 120b so as to at least partially cover the side surfaces of the MTBs 120a and 120b. In some embodiments, the pair of parallel edge portions 130e of the laminate sheet 130 can cover the entire side surfaces of the MTBs 120a and 120b that are parallel to the second direction (e.g., the Y-axis direction). In other embodiments, the pair of parallel edge portions 130e of the laminate sheet 130 can cover only a portion of the side surfaces of the MTBs 120a and 120b that are parallel to the second direction (e.g., the Y-axis direction).

[0099] The laminate sheet 130 may include a flexible metal layer 134 , an inner resin layer 132 provided on one side of the metal layer 134 , and an outer resin layer 136 provided on the other side of the metal layer 134 .

[0100] The metal layer 134 maintains an appropriate thickness and prevents water vapor, oxygen, and other gases from penetrating from the outside to the inside, thereby preventing leakage of the electrolyte. In some embodiments, the metal layer 134 may include, but is not limited to, any one or more selected from iron (Fe), carbon (C), chromium (Cr), manganese (Mn), nickel (Ni), aluminum (Al), and alloys thereof. When the metal layer 134 is made of a material containing iron, it has high mechanical strength, and when it is made of aluminum, it has good flexibility, so aluminum metal foil is typically used.

[0101] The metal layer 134 can be relatively easily deformed by an externally applied force and can be configured to have an appropriate thickness and mechanical strength so that cracks or holes do not occur even when repeatedly deformed.

[0102] In some embodiments, metal layer 134 can have a thickness of about 20 micrometers (μm) to about 100 μm. In some embodiments, metal layer 134 can have a thickness 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 a range between any two of these values.

[0103] The inner resin layer 132 provided on one side of the metal layer 134 may include a thermal adhesive layer. In some embodiments, the inner resin layer 132 may include a polyolefin-based material that can perform a sealing function by fusion. In some embodiments, the inner resin layer 132 may include modified propylene such as cast polypropylene (CPP), or a polypropylene-butylene-ethylene terpolymer.

[0104] The inner resin layer 132 may be formed by coating or laminating one side of the metal layer 134 .

[0105] The outer resin layer 136 provided on the other side of the metal layer 134 can act as a base substrate and a protective layer to form the laminate sheet 130. The outer resin layer 136 can include an insulating material such as polyethylene terephthalate (PET) or nylon.

[0106] In some embodiments, the inner resin layer 132 and the outer resin layer 136 may each have a thickness of about 10 micrometers (μm) to about 50 μm. In some embodiments, the thickness of the inner resin layer 132 and the outer resin layer 136 may be about 10 μm to about 50 μm, about 12 μm to about 48 μm, about 15 μm to about 45 μm, about 17 μm to about 43 μm, about 20 μm to about 40 μm, about 22 μm to about 38 μm, about 25 μm to about 35 μm, about 27 μm to about 33 μm, or a range between any two of these values.

[0107] In some embodiments, an adhesive resin layer may be further provided between the inner resin layer 132 and the metal layer 134 and / or between the outer resin layer 136 and the metal layer 134. The adhesive resin layer may be provided to facilitate smooth adhesion between different materials. The adhesive resin layer may be formed as a single layer or multiple layers. In some embodiments, the adhesive resin layer may include a polyolefin-based resin, a polyurethane-based resin, an epoxy-based resin, or a mixture thereof.

[0108] In some embodiments, the internal resin layer 132 may be fused to the fusion resin layers 122p provided on the sides of the MTBs 120a and 120b at both ends in the second direction (e.g., the Y-axis direction). The internal resin layer 132 may be fused to the fusion resin layers 122p while surrounding the sides of the MTBs 120a and 120b, thereby sealing the stacked electrode assembly 110 within the laminate sheet 130.

[0109] The inner resin layer 132 facing the first MTB 120a may be melted by heating and cooled while in contact with the fusion resin layer 122p on the side of the first MTB 120a, thereby being fused to the side of the first MTB 120a, thereby forming a first sealing portion 130m1. The inner resin layer 132 facing the second MTB 120b may be melted by heating and cooled while in contact with the fusion resin layer 122p on the side of the second MTB 120b, thereby being fused to the side of the second MTB 120b, thereby forming a second sealing portion 130m2.

[0110] The ends 130t of the laminate sheet 130 are fused together to form a joining section 130m (see FIG. 1) after surrounding the sides of the MTBs 120a and 120b and the stacked electrode assembly 110. Specifically, the laminate sheets 130 are adhered together at the joining section 130m so that the internal resin layers 132 face each other, and then the facing internal resin layers 132 can be fused together.

[0111] The interleaving portion 130m may be located on any one side of the stacked electrode assembly 110. In some embodiments, the interleaving portion 130m may be located in a third direction (e.g., the Z-axis direction) of the stacked electrode assembly 110 after surrounding the stacked electrode assembly 110.

[0112] (Second embodiment) FIG. 13 is a schematic perspective view of a battery pack 1 according to one embodiment of the present invention, FIG. 14 is an exploded perspective view showing the configuration of the battery pack 1 of FIG. 13, and FIG. 15 is a perspective view showing the battery cell 100 of FIG. 14 seated in a pack housing.

[0113] 13 to 15, a battery pack 1 according to one embodiment of the present invention includes a plurality of battery cells 100, an electrical component assembly 500, a pack housing 300, and a pack cover 600. In the battery pack 1 shown in FIG.

[0114] The battery cells 100 may be stacked in a first direction (e.g., the X-axis direction), with the cooling pads 200 interposed between the battery cells. In some embodiments, the stack of battery cells 100 and cooling pads 200 may be directly housed in the pack housing 300 without being housed in another frame. However, those skilled in the art will understand that various modifications are possible regarding the method of housing the battery cells 100.

[0115] For example, a stack of battery cells 100 and cooling pads 200 may be housed in a module frame to form a battery module, and the battery module may be housed in the pack housing 300. The module frame may be configured in the form of a rectangular box that surrounds the outer periphery of the stack of battery cells 100 and cooling pads 200 so that the stack of battery cells 100 and cooling pads 200 can be held therein. The module frame may be made of a metal material with high mechanical rigidity so as to sufficiently protect the battery cells 100 from swelling and external impacts of the battery cells 100.

[0116] The electrical equipment assembly 500 may include a relay device, a current sensor, a fuse, a BMS (Battery Management System), an MSD (Manual Service Disconnector), etc. The relay device is a switching component that selectively opens and closes a charge / discharge path through which current flows, and can cut off the flow of charge / discharge current when an abnormality occurs in the battery pack 1. The BMS refers to a battery management device that generally controls the charge / discharge operation of the battery cells 100, and can be said to be a component that is usually included in the battery pack 1. The MSD is a system for selectively cutting off the power supply of the high-voltage battery in a physical manner, and cuts off the power supply by separating the service plug when necessary.

[0117] The electrical equipment assembly 500 can be packaged together with the battery cell 100 by the pack housing 300 and the pack cover 600 so as not to be exposed to the outside.

[0118] The pack housing 300 can be said to be a structure that provides a space in which the battery cells 100 and the electrical equipment assembly 500 can be housed, and is provided with brackets 332 and mounting structures 343 and 353 so that it can be connected to the vehicle body.

[0119] The pack housing 300 provides mechanical support to the battery module 100 and the electrical component assembly 500 and protects them from external impacts, and therefore may be made of a highly rigid metal material.

[0120] The pack housing 300 according to this embodiment may include a lower frame 310 in the form of a wide plate on which the battery cells 100 can be mounted, and a front frame 320, a rear frame 330, a right side frame 340, and a left side frame 350 that are vertically coupled to the edges of the lower frame 310 to form walls. The pack housing 300 may further include a center beam 370 and a cross beam 360 to define a space in which the battery cells 100 can be mounted. One end of the center beam 370 may be coupled to the front frame 320 and the other end may be coupled to the rear frame 330. In some embodiments, the cross beam 360 may be coupled to the center beam 370 and the other end may be coupled to the right side frame 340 or the left side frame 350. In some embodiments, the cross beam 360 may extend across the center beam 370 and be coupled to the right side frame 340 and the other end may be coupled to the left side frame 350.

[0121] In some embodiments, lower frame 310, front frame 320, rear frame 330, right side frame 340, left side frame 350, and cross beam 360 may each be an aluminum extrusion structure, and pack housing 300 may be made by welding and / or bolting the frames together.

[0122] For example, by extruding aluminum to form the frame so that it has a mixture of empty space and ribs inside, and then welding them together to form the pack housing 300, the weight of the pack housing 300 can be reduced and the mechanical rigidity can be made to be more reliable than required.

[0123] In some embodiments, a heat sink may be further provided within the pack housing 300. The heat sink may be in the form of a plate-like body with a flow path therein so as to absorb and discharge heat from another object through thermal contact. In some embodiments, the lower frame 310 may include an inlet port 410a through which cooling water can flow, an outlet port 410b through which the cooling water can be discharged, and a cooling water channel through which the cooling water can flow.

[0124] The battery cells 100 may be electrically connected by inter-bus bars 510, 520, and 530. These inter-bus bars may include a first inter-bus bar 510 that electrically connects the battery modules 100 arranged in a 2×2 configuration along a first direction (e.g., the X-axis direction) and a second direction (e.g., the Y-axis direction). In some embodiments, the first inter-bus bar 510 may be provided at a position where the center beam 370 and the cross beams 360 intersect.

[0125] In addition, the inter-bus bar may include a second inter-bus bar 520 that electrically connects the electrically connected battery cells 100 to an external load or a charging system. The second inter-bus bar 520 does not need to be directly connected to the external load or charging system, but may be connected to the external load or charging system via the electrical component assembly 500.

[0126] The battery module 100 may include a first group of battery cells 100A located on one side of the center beam 370 and a second group of battery cells 100B located on the other side. The inter-bus bars may include a third inter-bus bar 530 that electrically connects the first group of battery cells 100A and the second group of battery cells 100B.

[0127] (Third embodiment) Fig. 16 is an exploded perspective view showing an end portion of a secondary battery 100 according to another embodiment of the present invention. The secondary battery 100 according to the embodiment shown in Fig. 16 differs from the embodiment described with reference to Fig. 4 only in that the number of electrode groups is increased. Therefore, the following description will focus on these differences, and overlapping points will not be described again.

[0128] 16, the busbar structure 125 may be electrically connected to the electrode tabs 116a, 116c, 116e, and 116f of the stacked electrode assembly 110. The busbar structure 125 may electrically connect the electrode tabs 116a, 116c, 116e, and 116f to the electrode terminal portion 124.

[0129] In some embodiments, the first bus bar plate 1251 may be a generally flat plate. The first bus bar plate 1251 may include slits 1251s through which the electrode tabs 116a, 116c, 116e, and 116f may pass. The first electrode tab 116a may have one corresponding slit 1251s. The third electrode tab 116c may have one corresponding slit 1251s.

[0130] The additional third electrode group 110c can have a fifth electrode tab 116e. The additional fourth electrode group 110d can have a sixth electrode tab 116f. The fifth electrode tab 116e can have one corresponding slit 1251s. The sixth electrode tab 116f can have one corresponding slit 1251s.

[0131] Those skilled in the art will appreciate that the electrode tabs located opposite electrode tabs 116a, 116c, 116e, and 116f may also have corresponding slits in the first bus bar plate housed in second MTB 120b.

[0132] The first electrode tabs 116a are provided on one side of the unit batteries belonging to the first electrode group 110a and are inserted into one of the slits 1251s. The third electrode tabs 116c are provided on one side of the unit batteries belonging to the second electrode group 110b and are inserted into another of the slits 1251s. The fifth electrode tabs 116e are provided on one side of the unit batteries belonging to the third electrode group 110c and are inserted into one of the slits 1251s. The sixth electrode tabs 116f are provided on one side of the unit batteries belonging to the fourth electrode group 110d and are inserted into another of the slits 1251s.

[0133] That is, the electrode tabs 116a, 116c, 116e, and 116f included in one electrode group 110a, 110b, 110c, and 110d can be inserted into one slit 1251s.

[0134] The above describes the first MTB 120a, but those skilled in the art will understand from the above that the second MTB 120b located on the opposite side of the first MTB 120a can also be configured in the same manner.

[0135] FIG. 17 is a schematic diagram showing a cross section of the end of the secondary battery 100 shown in FIG. 16 cut so as to pass through the electrode terminal portion 124. In FIG.

[0136] 17 , the plurality of electrode tabs 116a, 116c, 116e, and 116f may extend between the first bus bar plate 1251 and the second bus bar plate 1252. In some embodiments, the plurality of electrode tabs 116a, 116c, 116e, and 116f may extend along the interface between the first bus bar plate 1251 and the second bus bar plate 1252 after passing through the slits 1251s in the first bus bar plate 1251. In some embodiments, the plurality of electrode tabs 116a, 116c, 116e, and 116f may extend in a first direction (e.g., the X-axis direction) between the first bus bar plate 1251 and the second bus bar plate 1252.

[0137] 5, the ends of the electrode tabs 116a, 116c, 116e, and 116f have two sides that extend parallel to each other. In some embodiments, one side of the ends of the electrode tabs 116a, 116c, 116e, and 116f may contact the first bus bar plate 1251 and extend in a first direction (e.g., the X-axis direction). In some embodiments, the other side of the ends of the electrode tabs 116a, 116c, 116e, and 116f may contact the second bus bar plate 1252 and extend in the first direction (e.g., the X-axis direction).

[0138] In some embodiments, the electrode tabs 116a, 116c, 116e, and 116f may include shock absorbing portions that are bent in a predetermined direction in the portions that are not inserted into the slits 1251s.

[0139] Although the embodiments of the present invention have been described in detail above, those skilled in the art can implement the present invention in various modifications without departing from the spirit and scope of the present invention as defined in the appended claims. Therefore, future changes to the embodiments of the present invention cannot depart from the technology of the present invention. [Explanation of symbols]

[0140] 1: Battery pack 100: Secondary battery 110: Stacked electrode assembly 111: Unit battery 116, 116a, 116b, 116c, 116d, 116e, 116f: electrode tabs 120a: 1st MTB 120b: 2nd MTB 122:MTB housing 122h: Through hole 122p: Fusion resin layer 124: Electrode terminal part 125: Busbar structure 128: Check valve 129: Insulation gasket 130: Laminated sheet 200: Cooling pad 300: Pack housing 500: Electrical equipment assembly 600: Pack cover 1251: First bus bar plate 1251s:Slit 1252: Second bus bar plate 1252a: Part 1 1252b:Second part

Claims

1. a stacked electrode assembly in which a plurality of unit batteries are stacked in a first direction and each of the unit batteries has an electrode tab at each of both side edges in a second direction perpendicular to the first direction; a multi-function terminal block (MTB) provided at each end of the stacked electrode assembly; a laminate sheet that wraps the side surfaces of the stacked electrode assembly; Including, The MTB includes a busbar structure electrically connected to the electrode tabs, and an MTB housing that accommodates the busbar structure. The bus bar structure includes a first bus bar plate into which a plurality of electrode tabs are inserted, and a second bus bar plate in surface contact with the first bus bar plate.

2. the first bus bar plate includes two or more slits, The secondary battery according to claim 1 , wherein a plurality of electrode tabs are inserted into each of the slits.

3. The stacked electrode assembly includes two or more electrode groups, The secondary battery according to claim 2 , wherein an electrode tab included in one electrode group is inserted into one slit.

4. The secondary battery according to claim 1 , wherein the second bus bar plate is in surface contact with the first bus bar plate with the ends of the electrode tabs interposed therebetween.

5. The secondary battery according to claim 1 , wherein the second bus bar plate includes a first portion that is in surface contact with the first bus bar plate, and a second portion that extends from the first portion and is bent.

6. The secondary battery of claim 5 , wherein the second portion is electrically connected to an electrode terminal of the MTB.

7. The secondary battery according to claim 5 , wherein the second portion is bent 180 degrees and extends from the first portion.

8. The secondary battery according to claim 1 , wherein the first bus bar plate and the second bus bar plate are area-welded.

9. The secondary battery according to claim 8 , wherein the first bus bar plate and the second bus bar plate are joined by an electromagnetic pulse welding technique.

10. a stacked electrode assembly in which a plurality of unit batteries are stacked in a first direction and each of the unit batteries has an electrode tab at each of both side edges in a second direction perpendicular to the first direction; a multi-function terminal block (MTB) provided at each end of the stacked electrode assembly; a laminate sheet that wraps the side surfaces of the stacked electrode assembly; Including, The MTB includes a bus bar structure that electrically connects the electrode tabs, and an MTB housing that accommodates the bus bar structure, the bus bar structure includes a first bus bar plate and a second bus bar plate in surface contact with each other, the second bus bar plate including a first portion in surface contact with the first bus bar plate and a second portion extending from the first portion and bent.

11. the first portion includes a plurality of slits into which electrode tabs can be inserted; The secondary battery according to claim 10 , wherein a plurality of electrode tabs are inserted into each of the plurality of slits.

12. The secondary battery of claim 11 , wherein the plurality of electrode tabs extend between the first bus bar plate and the second bus bar plate.

13. 13. The secondary battery of claim 12, wherein the plurality of electrode tabs are integrated between the first bus bar plate and the second bus bar plate such that an interface with at least one of the first bus bar plate and the second bus bar plate is unclear.

14. The secondary battery according to claim 10 , wherein the second portion is bent 180 degrees and extends from the first portion.

15. The secondary battery according to claim 10 , wherein the first bus bar plate and the first portion of the second bus bar plate are joined by an electromagnetic pulse welding technique.

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