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 specifically, to a secondary battery having a bus bar structure capable of simply and highly reliably connecting a large number of electrode tabs.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0170392 filed on November 30, 2023, and all the contents disclosed in the document of the Korean patent application are included as part of this specification.

Background Art

[0003] Unlike a primary battery, a secondary battery can be charged and discharged multiple times. Secondary batteries are widely used as an energy source for various wireless devices such as mobile phones, notebook computers, and wireless vacuum cleaners. In recent years, due to the improvement of energy density and economies of scale, the manufacturing cost per unit capacity of secondary batteries has decreased epochally, and as the driving range of BEV (battery electric vehicle) increases to a level equivalent to that of fuel vehicles, the main use of secondary batteries has shifted from mobile devices to mobility.

[0004] On the other hand, in recent years, the demand for large-capacity battery packs applied to electric vehicles and the like has been increasing. The large-capacity battery packs installed in automobiles are required to enhance safety along with an increase in capacity.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The technical problem to be achieved by the present invention is to provide a secondary battery having a bus bar structure capable of simply and highly reliably connecting a large number of electrode tabs.

Means for Solving the Problems

[0006] To achieve the above technical problems, the present invention provides a secondary battery comprising: a stacked electrode assembly in which a plurality of unit batteries are stacked in a first direction and having the respective electrode tabs of the plurality of unit batteries 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 sides 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 a plurality of electrode tabs are inserted together and a second busbar plate that is in surface contact with the first busbar plate.

[0007] In some embodiments, the first busbar plate includes two or more slits into which multiple electrode tabs can be inserted.

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

[0009] In some embodiments, the second busbar plate can be in surface contact with the first busbar plate with the ends of the plurality of electrode tabs in between.

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

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

[0012] In some embodiments, the second portion can be extended by folding it 180 degrees from the first portion.

[0013] In some embodiments, the first busbar plate and the second busbar plate can be area-welded together.

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

[0015] Another aspect of the present invention provides a secondary battery comprising: a stacked electrode assembly having a plurality of unit batteries stacked in a first direction and having electrode tabs of the plurality of unit batteries 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 sides of the stacked electrode assembly, wherein the MTB comprises a busbar structure electrically connecting the electrode tabs and an MTB housing housing the busbar structure, the busbar structure comprising a first busbar plate and a second busbar plate in surface contact with each other, and the second busbar plate comprising 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 includes a plurality of slits into which electrode tabs can be inserted, and each of the plurality of slits may have a plurality of electrode tabs inserted into it.

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

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

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

[0020] In some embodiments, the first portions of the first bus bar plate and the second bus bar plate may be joined by electromagnetic pulse welding technology (EMPT).

Advantages of the Invention

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

[0022] The effects obtainable from the exemplary embodiments of the present invention are not limited to the above-described effects, and other effects not mentioned can be clearly derived and understood by those having ordinary knowledge in the technical field to which the exemplary embodiments of the present disclosure belong from the following description. That is, unintended effects associated with implementing the exemplary embodiments of the present disclosure can also be derived by those having ordinary knowledge in the technical field from the exemplary embodiments of the present disclosure.

Brief Description of the Drawings

[0023] [Figure 1] FIG. 1 is a perspective view showing a main part of a secondary battery according to an embodiment of the present invention. [Figure 2] FIG. 2 is a partial perspective view showing an enlarged part of the secondary battery of FIG. 1. [Figure 3] FIG. 3 is a schematic perspective view showing a state where a laminate sheet is removed from the secondary battery of FIG. 1. [Figure 4] FIG. 4 is an exploded perspective view showing an end portion of a secondary battery according to an embodiment of the present invention. [Figure 5] FIG. 5 is a schematic view showing a cross section taken by cutting the end portion of the secondary battery shown in FIG. 4 so as to pass through the electrode terminal portion. [Figure 6]FIG. 6 is a conceptual diagram showing a method of coupling a plurality of electrode tabs to a first bus bar plate and a second bus bar plate. [Figure 7] FIG. 7 is a conceptual diagram showing a state in which a plurality of electrode tabs are integrated when the first bus bar plate and the second bus bar plate are joined. [Figure 8] FIG. 8 is a conceptual diagram showing a state in which a plurality of electrode tabs are integrated when the first bus bar plate and the second bus bar plate are joined. [Figure 9] FIG. 9 is a conceptual diagram showing a state in which a plurality of electrode tabs are integrated when the first bus bar plate and the second bus bar plate are joined. [Figure 10] FIG. 10 is a schematic side view showing a main part of an end portion of a secondary battery according to an embodiment of the present invention. [Figure 11] FIG. 11 is a partially exploded perspective view showing a bonding method of a laminate sheet of a secondary battery according to an embodiment of the present invention. [Figure 12] FIG. 12 is a partial cross-sectional view of a laminate sheet according to an embodiment of the present invention. [Figure 13] FIG. 13 is a schematic perspective view of a battery pack according to an embodiment of the present invention. [Figure 14] FIG. 14 is an exploded perspective view schematically showing the configuration of the battery pack of FIG. 13. [Figure 15] FIG. 15 is a perspective view showing a state in which the battery cells of FIG. 14 are 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 view showing a cross-section of the end portion of the secondary battery shown in FIG. 16 cut through an electrode terminal portion.

MODE FOR CARRYING OUT THE INVENTION

[0024] Preferred embodiments of the concept of the present invention will be described in detail below with reference to the accompanying drawings. However, embodiments of the concept of the present invention can be modified into various different forms, and the scope of the concept of the present invention should not be construed as being limited by the embodiments described below. It is preferable that embodiments of the concept of the present invention be construed as being provided to more fully explain the concept of the present invention to a person of average skill in the art. The same reference numerals mean the same element throughout. Furthermore, various elements and areas in the drawings are depicted schematically. Therefore, the concept of the present invention is not limited by the relative sizes or spacings depicted in the accompanying drawings.

[0025] Terms such as "first," "second," etc., can be used to describe various components, but these components are not limited by these terms. These terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the concept of the present invention, the first component may be named the second component, and conversely, the second component may be named the first component.

[0026] The terms used in this application are used solely to describe specific embodiments and are not intended to limit the concepts of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, expressions such as “includes” or “has” are intended to specify the presence of features, quantities, steps, operations, components, parts, or combinations thereof described in the specification, and are understood not to pre-exist to exclude the presence or possibility of adding one or more other features, quantities, 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 those commonly understood by those of ordinary skill in the art to which the concepts of this invention pertain. Furthermore, terms defined in commonly used dictionaries may be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and should not be interpreted in an overly formal sense unless explicitly defined herein.

[0028] Where a particular embodiment can be otherwise realized, a specific sequence of steps may be performed in a different order than that described. For example, two steps described consecutively may be performed substantially simultaneously, or in the reverse order of the description.

[0029] In the accompanying drawings, deformations of the shown shapes can be expected, for example, due to manufacturing techniques and / or tolerances. Therefore, embodiments of the present invention should not be construed as being limited to specific shapes of the regions shown herein, and may include, for example, changes in shape brought about during the manufacturing process. All terms used herein, "and / or," include each of the components mentioned and all combinations of one or more of them. The term "substrate" as used herein may mean the substrate itself or a laminated structure including a predetermined layer or film formed on the substrate. The term "surface of the substrate" as used herein may mean the exposed surface of the substrate itself or an outer surface including a predetermined layer or film formed on the substrate.

[0030] (First Embodiment) Figure 1 is a perspective view showing the main parts of a secondary battery 100 according to one embodiment of the present invention. Figure 2 is a partial perspective view showing an enlarged portion of the secondary battery 100 in Figure 1. Figure 3 is a schematic perspective view showing the secondary battery 100 in Figure 1 with the laminate sheet 130 removed.

[0031] In the following drawings, the secondary battery 100 is shown as being defined in a vertical coordinate system defined as a first direction along the X-axis, a second direction along the Y-axis, and a third direction along the Z-axis, all of which are perpendicular to each other. However, the first, second, and third directions only need to be perpendicular to each other and are not particularly limited.

[0032] Referring to Figures 1 to 3, the secondary battery 100 includes a stacked electrode assembly 110, multifunctional terminal blocks (MTBs) 120a and 120b, and a laminate sheet 130.

[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 unit cell 111 may have an electrode material coated on a metal foil that acts as a current collector.

[0034] Each unit cell 111 may have a thin, plate-like body extending in a second direction (for example, the Y-axis direction). Each unit cell 111 may be a positive electrode unit cell or a negative electrode unit cell. In some embodiments, a plurality of unit cells 111 may be stacked alternately with one positive electrode unit cell and one negative electrode unit cell. These positive electrode and negative electrode unit cells may be separated from each other by a separator membrane.

[0035] In some other embodiments, the plurality of unit cells 111 may consist of a plurality of positive electrode unit cells and a plurality of negative electrode unit cells stacked alternately. These plurality of positive electrode unit cells and a plurality of negative electrode unit cells may be separated from each other by a separator membrane.

[0036] The stacked electrode assembly 110 may have electrode tabs 116 at both ends in a second direction (for example, the Y-axis direction). The electrode tabs 116 may be extensions of the plain portion of the current collector of a plurality of unit batteries 111.

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

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

[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, differing only in polarity. The first MTB 120a will be described below, and those skilled in the art will be able to learn the configuration of the second MTB 120b from this.

[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 Figure 4) that electrically connects the electrode terminal portion 124 and the electrode tab 116 laminated to it.

[0041] The MTB housing 122 may contain a material with relatively high rigidity, such as metal, and defines the appearance of the first MTB 120a. In some embodiments, the MTB housing 122 may consist 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 can be provided in the MTB housing 122 such that the electrode terminal portion 124 is exposed in a second direction (e.g., the Y-axis direction). Therefore, the through-hole 122h can be provided on a plane perpendicular to the second direction (e.g., the Y-axis direction) of the MTB housing 122. The through-hole 122h may also have an opening that is open in the longitudinal direction of the electrode assembly 110. The shape of the through-hole 122h can 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 that is exposed to the outside from the MTB housing 122 may be planar. In some embodiments, the exposed surface may have a plane that extends perpendicularly in a second direction (e.g., the Y-axis direction). In some embodiments, the electrode terminal portion 124 may have a disk-shaped free surface that is exposed to the outside.

[0044] In some embodiments, an electrically insulating gasket 129 can 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.

[0045] In some embodiments, the first MTB 120a may include a rupture disk configured to release gases causing an excessive increase in internal pressure in the secondary battery 100 by rupturing if the internal pressure of the secondary battery 100 increases excessively. The rupture disk, once it ruptures due to a thermal event occurring inside the secondary battery 100, will not be restored to its original state. The venture disk may be any venture disk known in the art and is not particularly limited.

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

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

[0048] The aforementioned polyolefin resins include, for example, polyethylene, polypropylene, poly(1-butene), poly(4-methyl-1-pentene), ethylene-propylene copolymer, copolymer of ethylene and 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 polyolefins obtained by grafting these with unsaturated carboxylic acids or their derivatives, but the present invention is not limited thereto.

[0049] The aforementioned polyester resin includes, 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 fused resin layer 122p may be unstretched (casted), or it may be uniaxially or biaxially stretched or rolled.

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

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

[0054] In some embodiments, the fused resin layer 122p can be extended along the side surface of the MTB housing 122, having a constant width between the inner end 122ie and the outer end 122oe.

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

[0056] The fused resin layer 122p can have a thickness of, for example, about 20 μm to about 400 μm. In some embodiments, the fused 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 fused resin layer 122p is too thin, the mechanical strength may be insufficient. If the thickness of the fused resin layer 122p is too thick, it may be economically disadvantageous.

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

[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 release 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 the release of the gas. The check valve 128 has no part that would burst upon the release of the gas and can be restored to its original state after the internal gas has been released.

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

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

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

[0063] The busbar structure 125 can be electrically connected to the electrode tabs 116a and 116c of the stacked electrode assembly 110. The busbar structure 125 can also be electrically connected to 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 connected 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 can each be independently 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 materials.

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

[0067] Specifically, the first electrode tab 116a consists of multiple electrode tabs provided on one side of multiple unit batteries belonging to the first electrode group 110a, and these are inserted into one slit 1251s. Similarly, the third electrode tab 116c consists of multiple electrode tabs provided on one side of multiple unit batteries belonging to the second electrode group 110b, and these are inserted into another slit 1251s. In other words, one slit 1251s can accommodate electrode tabs 116a and 116c belonging to one electrode group 110a or 110b.

[0068] The second busbar plate 1252 may include a first portion 1252a configured to make area contact with the first busbar plate 1251. The second busbar plate 1252 may also include a second portion 1252b that is electrically connected to the first portion 1252a and extends from the first portion 1252a by being bent. In some embodiments, the second portion 1252b may be bent 180 degrees from the first portion 1252a and extended. 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 busbar plate 1252 may extend substantially parallel to the second portion 1252b. The first portion 1252a and the second portion 1252b may be two portions located on opposite sides of a single bent plate.

[0070] The busbar structure 125 can be housed within the MTB housing 122. The busbar structure 125 can be electrically connected to an electrode terminal portion 124 that extends through a through-hole 122h of the MTB housing 122. In some embodiments, the busbar structure 125 can be configured to make direct contact with the electrode terminal portion 124. In some embodiments, the electrode terminal portion 124 can be configured to make direct contact with a second busbar plate 1252 of the busbar structure 125. In some embodiments, the electrode terminal portion 124 can be configured to make direct contact with a second portion 1252b of the second busbar plate 1252.

[0071] The first MTB120a has been described above, but those skilled in the art will understand from the above description that the second MTB120b, located on the opposite side of the first MTB120a, can be constructed in the same manner.

[0072] Figure 5 is a schematic diagram showing a cross-section of the secondary battery 100 shown in Figure 4, with the end portion cut through the electrode terminal portion 124.

[0073] Referring to Figure 5, the multiple electrode tabs 116a, 116c can extend between the first busbar plate 1251 and the second busbar plate 1252. In some embodiments, the multiple electrode tabs 116a, 116c can extend along the interface between the first busbar plate 1251 and the second busbar plate 1252 after passing through the slit 1251s of the first busbar plate 1251. In some embodiments, the multiple electrode tabs 116a, 116c can extend in a first direction (e.g., the X-axis direction) between the first busbar plate 1251 and the second busbar plate 1252.

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

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

[0076] Figure 6 is a conceptual diagram showing a method for coupling multiple electrode tabs 116a with the first busbar plate 1251 and the second busbar plate 1252.

[0077] Referring to Figure 6, multiple electrode tabs 116a can be passed through slits 1251s formed in the first busbar plate 1251. Subsequently, the ends of the multiple electrode tabs 116a can be bent in one direction. At this time, the ends of the multiple electrode tabs 116a do not need to be in close contact with the first busbar plate 1251.

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

[0079] Methods for area welding include, for example, explosive welding, pressure welding, and electromagnetic pulse welding (EMPT). In some embodiments, the second busbar plate 1252 can be joined to the first busbar plate 1251 by EMPT. When using EMPT 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 in place.

[0080] Area welding can achieve a more robust joint strength compared to joining methods that join only along specific lines or at specific points, because the second busbar plate 1252 is joined to the first busbar plate 1251 over a predetermined area. In particular, the EMPT method can join the first busbar plate 1251 and the second busbar plate 1252 with high reliability and at a high speed.

[0081] By joining the first busbar plate 1251 and the second busbar plate 1252, the ends of the multiple 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 multiple electrode tabs 116a can be integrated with the first busbar plate 1251. In some embodiments, the ends of the multiple electrode tabs 116a can be integrated with the second busbar plate 1252.

[0082] Conventionally, in order to electrically connect multiple electrode tabs to a busbar, it was necessary to first weld the electrode tabs together and then weld them to the electrode leads. However, in the embodiment of the present invention, not only are the electrode leads omitted, but after inserting the multiple electrode tabs belonging to each electrode group into the busbar structure, the entire electrode tab assembly is welded at once, thereby significantly simplifying the manufacturing process. Furthermore, since the electrode tabs are cold-welded, they can be bonded to the busbar structure with high reliability and joint strength, and defects due to welding burn can be prevented.

[0083] Figures 7 to 9 are conceptual diagrams showing how multiple electrode tabs 116 are integrated when the first busbar plate 1251 and the second busbar plate 1252 are joined together.

[0084] Referring to Figure 7, the first busbar plate 1251 and the second busbar plate 1252 can be brought into close contact with each other by joining them. The multiple electrode tabs 116 can be extended between the first busbar plate 1251 and the second busbar plate 1252 after passing through the slit in the first busbar plate 1251. By joining the first busbar plate 1251 and the second busbar plate 1252, the multiple electrode tabs 116 can be integrated with the second busbar plate 1252. In some embodiments, the multiple electrode tabs 116 can be integrated such that the interface with the second busbar plate 1252 is unconfirmed. In Figure 7, the dotted line between the multiple electrode tabs 116 and the second busbar plate 1252 conceptually shows the interface before complete joining.

[0085] In some embodiments, an interface can be identified between the multiple electrode tabs 116 and the first busbar plate 1251. However, even if such an interface is identified, the multiple electrode tabs 116 and the first busbar plate 1251 are in extremely close contact, ensuring sufficient bonding strength and electrical conductivity.

[0086] In Figure 7, an interface is shown to exist between the first busbar plate 1251 and the second busbar plate 1252. However, a person skilled in the art will understand that, depending on the area welding method and conditions, an interface may not be observed between the first busbar plate 1251 and the second busbar plate 1252.

[0087] Referring to Figure 8, the multiple electrode tabs 116 can be integrated with the first busbar plate 1251 by joining the first busbar plate 1251 and the second busbar plate 1252. In some embodiments, the multiple electrode tabs 116 can be integrated in such a way that the interface with the first busbar plate 1251 is not visible. In Figure 8, the dotted line between the multiple electrode tabs 116 and the first busbar plate 1252 conceptually shows the interface before complete joining.

[0088] In some embodiments, an interface can be identified between the multiple electrode tabs 116 and the second busbar plate 1252. However, even if an interface is identified, the multiple electrode tabs 116 and the second busbar plate 1252 are in extremely close contact, so sufficient bonding strength and electrical conductivity can be compensated for.

[0089] In Figure 8, an interface is shown to exist between the first busbar plate 1251 and the second busbar plate 1252. However, a person skilled in the art will understand that, depending on the area welding method and conditions, an interface may not be observed between the first busbar plate 1251 and the second busbar plate 1252.

[0090] Referring to Figure 9, the multiple electrode tabs 116 can be integrated with the first busbar plate 1251 and the second busbar plate 1252 by joining the first busbar plate 1251 and the second busbar plate 1252. In some embodiments, the multiple electrode tabs 116 can be integrated in such a way that the interface with the first busbar plate 1251 and the second busbar plate 1252 is not visible.

[0091] In Figure 9, an interface is shown to exist between the first busbar plate 1251 and the second busbar plate 1252. However, a person skilled in the art will understand that, depending on the area welding method and conditions, an interface may not be observed between the first busbar plate 1251 and the second busbar plate 1252.

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

[0093] Referring to Figure 10, the busbar structure 125 is housed within the MTB housing 122, and the busbar structure 125 can be electrically connected to the electrode terminals 124. Multiple overlapping electrode tabs 116 can pass through the 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 busbar plate 1252 can make surface contact with the first busbar plate 1251. The second portion 1252b of the second busbar plate 1252 can extend from the first portion 1252a and be bent 180 degrees. The second portion 1252b can be electrically connected to the electrode terminal portion 124. In some embodiments, the second portion 1252b can make direct contact with the electrode terminal portion 124. In some embodiments, the second portion 1252b can be electrically connected to the electrode terminal portion 124 via another conductor.

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

[0096] Figure 10 shows an example in which the second busbar plate 1252 is bent 180 degrees with respect to the X-axis, but a person skilled in the art will understand that the second busbar plate 1252 may also be bent 180 degrees with respect to the Z-axis.

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

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

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

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

[0101] The metal layer 134 can be configured to be relatively easily deformable by external forces and to have an appropriate thickness and mechanical strength such that cracks or holes do not occur even with repeated deformation.

[0102] In some embodiments, the metal layer 134 can have a thickness of about 20 micrometers (μm) to about 100 μm. In some embodiments, the thickness of the metal layer 134 can be in the 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.

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

[0104] The internal resin layer 132 can be formed by coating or laminating it to 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 protective layer for forming the laminate sheet 130. The outer resin layer 136 may contain insulating materials such as polyethylene terephthalate (PET) or nylon.

[0106] In some embodiments, the internal resin layer 132 and the external resin layer 136 can each have a thickness of about 10 micrometers (μm) to about 50 μm. In some embodiments, the thickness of the internal resin layer 132 and the external resin layer 136 can be in the range 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 any two of these values.

[0107] In some embodiments, an adhesive resin layer may be further provided between the internal resin layer 132 and the metal layer 134, and / or between the external resin layer 136 and the metal layer 134. The adhesive resin layer may be provided for smooth adhesion between dissimilar materials. The adhesive resin layer may be formed as a single layer or multiple layers. In some embodiments, the adhesive resin layer may include a polyolefin resin, a polyurethane resin, an epoxy resin, or a mixture thereof.

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

[0109] The internal resin layer 132 facing the first MTB 120a is melted by heating while in contact with the fused resin layer 122p on the side surface of the first MTB 120a, and then cooled, thereby fusing it onto the side surface of the first MTB 120a, and thus forming the first sealing portion 130m1. The internal resin layer 132 facing the second MTB 120b is melted by heating while in contact with the fused resin layer 122p on the side surface of the second MTB 120b, and then cooled, thereby fusing it onto the side surface of the second MTB 120b, and thus forming the second sealing portion 130m2.

[0110] The edges 130t of the laminate sheet 130 surround the sides of the MTB 120a and 120b and the stacked electrode assembly 110, and are then fused together to form a laminated section 130m (see Figure 1). Specifically, the laminate sheet 130 can be fused together after the internal resin layers 132 of the laminate sheet 130m are brought into close contact with each other so that they face each other.

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

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

[0113] Referring to Figures 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.

[0114] The battery cells 100 are stacked in a first direction (e.g., the X-axis direction), and cooling pads 200 can be interposed between the battery cells. In some embodiments, the stack of battery cells 100 and cooling pads 200 can be housed directly 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 such battery cells 100.

[0115] For example, a laminate of battery cells 100 and cooling pads 200 can be housed in a module frame to form a battery module, which can then be housed in a pack housing 300. The module frame can be configured as a rectangular box surrounding the outer casing of such a laminate of battery cells 100 and cooling pads 200, so that the laminate of battery cells 100 and cooling pads 200 can be held inside. The module frame can be made of a metal material with high mechanical rigidity so as to adequately protect the battery cells 100 from swelling and external impacts.

[0116] The electrical component assembly 500 may include a relay device, current sensor, fuse, BMS (Battery Management System), MSD (Manual Service Disconnector), etc. The relay device is a switching component that selectively opens and closes the charge and discharge path through which current flows, and can interrupt the flow of charge and discharge current when an abnormal condition occurs in the battery pack 1. The BMS refers to a battery management device that comprehensively controls the charge and 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 interrupting the power supply of the high-voltage battery by a physical method, and disconnects the service plug to cut off the power when necessary.

[0117] Such an electrical component assembly 500 can be packaged together with the battery cell 100 by a pack housing 300 and a pack cover 600 so that it is not exposed to the outside.

[0118] The pack housing 300 is a structure that provides space to house the battery cell 100 and the electrical component assembly 500, and is equipped with brackets 332 and mounting structures 343 and 353 so that it can be attached 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 shocks, so it can be made of a highly rigid metal material.

[0120] The pack housing 300 according to this embodiment may include a lower frame 310 provided in the form of a broad plate-like body on which 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 which are perpendicularly coupled along the edge of such lower frame 310 to form a wall. The pack housing 300 may further include a center beam 370 and a cross beam 360 to define a space on which battery cells 100 can be mounted. The center beam 370 may have one end coupled to the front frame 320 and the other end coupled to the rear frame 330. In some embodiments, the cross beam 360 may have one end coupled to the center beam 370 and the other end coupled to the right side frame 340 or the left side frame 350. In some embodiments, the cross beam 360 may extend across the center beam 370, with one end coupled to the right side frame 340 and the other end coupled to the left side frame 350.

[0121] In some embodiments, the lower frame 310, front frame 320, rear frame 330, right side frame 340, left side frame 350, and crossbeam 360 may each be aluminum extruded structures, and the pack housing 300 may be constructed by welding and / or bolting the frames together.

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

[0123] In some embodiments, a heat sink may be further provided within the pack housing 300. The heat sink may be provided in the form of a plate-like body with internal channels to absorb and dissipate heat from other objects by thermal contact. In some embodiments, the lower frame 310 may include an inlet port 410a into which cooling water can flow, an outlet port 410b from which cooling water can be discharged, and a cooling water channel through which cooling water can flow.

[0124] The battery cells 100 can be electrically connected by interbus bars 510, 520, and 530. These interbus bars may include a first interbus bar 510 that electrically connects battery modules 100 arranged in a 2x2 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 interbus bar 510 may be provided at the intersection of the center beam 370 and the cross beam 360.

[0125] Furthermore, the above-mentioned interbusbar may include a second interbusbar 520 that electrically connects the electrically coupled battery cells 100 to an external load or charging system. The second interbusbar 520 does not need to be directly connected to the external load or charging system, but can be connected to the external load or charging system via an 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 interbus bar may include a third interbus bar 530 that electrically connects the first group of battery cells 100A and the second group of battery cells 100B.

[0127] (Third embodiment) Figure 16 is an exploded perspective view showing the end of a secondary battery 100 according to another embodiment of the present invention. The secondary battery 100 of the embodiment shown in Figure 16 differs from the embodiment described with reference to Figure 4 only in the number of electrode groups. Therefore, the following explanation will focus on these differences, and explanations of overlapping matters will be omitted.

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

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

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

[0131] Those skilled in the art will understand that the electrode tabs located on the opposite side of electrode tabs 116a, 116c, 116e, and 116f may also have corresponding slits within the first busbar plate housed in the second MTB 120b.

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

[0133] In other words, electrode tabs 116a, 116c, 116e, and 116f, which are part of one electrode group 110a, 110b, 110c, and 110d, can be inserted into one slit 1251s.

[0134] The first MTB120a has been described above, but those skilled in the art will understand from the above description that the second MTB120b, located on the opposite side of the first MTB120a, can be configured in the same way.

[0135] Figure 17 is a schematic diagram showing a cross-section of the secondary battery 100 shown in Figure 16, with the end passing through the electrode terminal portion 124.

[0136] Referring to Figure 17, the multiple electrode tabs 116a, 116c, 116e, and 116f can extend between the first busbar plate 1251 and the second busbar plate 1252. In some embodiments, the multiple electrode tabs 116a, 116c, 116e, and 116f can extend along the interface between the first busbar plate 1251 and the second busbar plate 1252 after passing through the slit 1251s of the first busbar plate 1251. In some embodiments, the multiple electrode tabs 116a, 116c, 116e, and 116f can extend in a first direction (e.g., the X-axis direction) between the first busbar plate 1251 and the second busbar plate 1252.

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

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

[0139] Although embodiments of the present invention have been described in detail above, any person with ordinary skill in the art to which the present invention pertains can modify and implement the present invention in various ways without departing from the spirit and scope of the invention as defined in the appended claims. Therefore, future modifications of embodiments of the present invention will not depart from the art 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: Insulating gasket 130: Laminating sheet 200: Cooling pad 300: Pack Housing 500: Electrical component 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 having multiple unit batteries stacked in a first direction, and each of the electrode tabs of the multiple unit batteries at both ends in a second direction perpendicular to the first direction, Terminal blocks provided at both ends of the stacked electrode assembly, A laminate sheet that encloses the side of the stacked electrode assembly, Includes, The terminal block includes a busbar structure electrically connected to the electrode tab and a housing that accommodates the busbar structure. The busbar structure includes a first busbar plate into which multiple electrode tabs are inserted together, and a second busbar plate that is in surface contact with the first busbar plate. The second busbar plate includes a first portion that is in surface contact with the first busbar plate, and a second portion that extends from the first portion and is bent 180 degrees. A secondary battery wherein the first portion of the second busbar plate is in surface contact with the first busbar plate across the entire surface facing the first busbar plate with the ends of the plurality of electrode tabs in between.

2. The first busbar plate includes two or more slits, The secondary battery according to claim 1, wherein multiple electrode tabs are inserted into each slit.

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

4. The secondary battery according to claim 1, wherein the second portion is electrically connected to the electrode terminal portion of the terminal block.

5. The secondary battery according to claim 1, wherein the first busbar plate and the second busbar plate are area-welded together.

6. The secondary battery according to claim 5, wherein the first busbar plate and the second busbar plate are joined by electromagnetic pulse welding technology.

7. A stacked electrode assembly having multiple unit batteries stacked in a first direction, and each of the electrode tabs of the multiple unit batteries at both ends in a second direction perpendicular to the first direction, Terminal blocks provided at both ends of the stacked electrode assembly, A laminate sheet that encloses the side of the stacked electrode assembly, Includes, The terminal block includes a busbar structure that electrically connects the electrode tabs and a housing that accommodates the busbar structure. The busbar structure includes a first busbar plate and a second busbar plate that are in surface contact with each other with the ends of the electrode tabs in between, the second busbar plate includes a first portion that is in surface contact with the first busbar plate and a second portion that extends from the first portion and is bent at 180 degrees, The first part is a secondary battery that makes surface contact with the first busbar plate over the entire surface facing the first busbar plate.

8. The first part includes a plurality of slits into which electrode tabs can be inserted, The secondary battery according to claim 7, wherein a plurality of electrode tabs are inserted into each of the plurality of slits.

9. The secondary battery according to claim 8, wherein the plurality of electrode tabs extend between the first busbar plate and the second busbar plate.

10. The secondary battery according to claim 9, wherein the plurality of electrode tabs are integrated between the first busbar plate and the second busbar plate such that the interface with at least one of the first busbar plate and the second busbar plate is unconfirmed.

11. The secondary battery according to claim 7, wherein the first portion of the first busbar plate and the second busbar plate are joined by electromagnetic pulse welding technology.

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