Battery pack and manufacturing method thereof

Abstract

In a vertical coordinate system defined by a first direction, a second direction, and a third direction perpendicular to each other, the battery pack includes: a plurality of battery cells stacked in the first direction; a pack case including an internal space capable of accommodating the plurality of battery cells; and a wiring structure provided on the pack case, wherein each of at least two adjacent battery cells among the battery cells includes an electrode assembly, a cover surrounding the electrode assembly, and a cell lead protruding in the second direction from one side of the cover, the cell lead having a first portion relatively close to the cover and a second portion relatively farther from the cover. a second portion spaced farther apart from the first portion, the pack case including a pair of first outer walls extending in the first direction, a pair of second outer walls extending in the second direction and defining an internal space of the pack case together with the pair of first outer walls, and a longitudinal beam extending between the pair of first outer walls and parallel to the first outer walls, the wiring structure including a wiring board and a plurality of bus bars extending in the first direction on the wiring board, each of the bus bars configured to electrically connect adjacent second portions to each other by extending in the first direction.

Description

[Technical Field]

[0001] The present invention relates to a battery pack and a manufacturing method thereof, and more specifically to a battery pack that can be manufactured inexpensively using a simple number of parts, has excellent productivity, and has little risk of product failure, and a manufacturing method thereof.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0167139, filed December 2, 2022, and Korean Patent Application No. 10-2023-0039689, filed March 27, 2023, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference. [Background technology]

[0003] As technological development and demand for various mobile devices, electric vehicles, energy storage systems (ESS), etc. has increased significantly, interest in and demand for secondary batteries as an energy source has been growing rapidly. While nickel-cadmium batteries and nickel-metal hydride batteries have traditionally been widely used as secondary batteries, lithium secondary batteries have recently come into widespread use due to their low memory effect compared to nickel-based secondary batteries, their flexible charging and discharging, extremely low self-discharge rate, and high energy density.

[0004] Such lithium secondary batteries mainly use lithium-based oxides and carbon materials as the positive and negative electrode active materials, respectively, and include an electrode assembly in which positive and negative electrode plates coated with the positive and negative electrode active materials are disposed with a separator between them, and an exterior material, i.e., a battery case, that hermetically houses the electrode assembly together with an electrolyte.

[0005] In recent years, battery packs have been widely used for driving and storing energy in medium- to large-sized devices such as electric vehicles and energy storage systems. A conventional battery pack includes one or more battery modules and a control unit, such as a battery management system (BMS), that controls the charging and discharging of the battery pack inside a pack case. Here, a battery module is configured to include a number of battery cells inside a module case. That is, in the case of a conventional battery pack, a number of battery cells (secondary batteries) are housed inside a module case to form each battery module, and such battery modules are housed inside one or more pack cases to form a battery pack.

[0006] In particular, pouch-type batteries have various advantages, such as being lightweight and leaving little dead space when stacked, but they also have weaknesses, such as being vulnerable to external impacts and somewhat reducing assembly. Therefore, battery packs are generally manufactured by first modularizing a number of cells and then housing them inside a pack case. As a representative example, in the case of a conventional battery pack, a number of pouch-type battery cells are first housed inside a module case to form a battery module, and then the battery module is housed inside one or more pack cases.

[0007] However, such conventional battery packs may be disadvantageous in terms of energy density. Typically, in the process of modularizing a number of battery cells by housing them inside a module case, various components such as the module case or a stacking frame may unnecessarily increase the volume of the battery pack or reduce the space occupied by the battery cells. Furthermore, the space occupied by the components themselves, such as the module case or the stacking frame, may be reduced, as well as the space occupied by the battery cells may be reduced to ensure assembly tolerances for these components. Therefore, in the case of conventional battery packs, there may be limitations on increasing energy density.

[0008] In addition, conventional battery packs can be disadvantageous in terms of assembly. In particular, manufacturing a battery pack requires first modularizing a number of battery cells to form a battery module, and then housing the battery module in a pack case, which complicates the manufacturing process of the battery pack. Furthermore, as disclosed in the above-mentioned prior art, the process and structure of forming a cell stack using a stacking frame, bolts, plates, etc. can be very complicated. Summary of the Invention [Problem to be solved by the invention]

[0009] A first technical problem that the present invention aims to achieve is to provide a battery pack that can be manufactured inexpensively using a simple number of parts, has excellent productivity, and has little risk of product failure.

[0010] The second technical problem that the present invention aims to achieve is to provide a method for manufacturing a battery pack that can be manufactured inexpensively using a simple number of parts, has excellent productivity, and has little risk of product failure. [Means for solving the problem]

[0011] To achieve the first technical object, the present invention provides a pack case including a plurality of battery cells stacked in a first direction in a vertical coordinate system defined by a first direction, a second direction, and a third direction perpendicular to each other, the pack case including an internal space capable of accommodating the plurality of battery cells, and a wiring structure provided on the pack case, wherein each of at least two adjacent battery cells among the battery cells includes an electrode assembly, a cover surrounding the electrode assembly, and a cell lead protruding from one side of the cover in the second direction, the cell lead including a first portion relatively close to the cover and a second portion relatively farther away from the cover, and the pack case includes a pair of first outer walls extending in the first direction, a pair of second outer walls extending in the second direction and defining an internal space of the pack case together with the pair of first outer walls, and a longitudinal beam extending between the pair of first outer walls and parallel to the first outer walls. the wiring structure includes a wiring board and a plurality of bus bars extending in the first direction on the wiring board, each of the bus bars configured to electrically couple adjacent second portions to each other by extending in the first direction.

[0012] In some embodiments, the wiring structure may be provided on an upper surface of the longitudinal beam.

[0013] In some embodiments, the cell lead may be configured such that the maximum dimension of the second portion is greater than the maximum dimension of the first portion in the first direction, and the second portion of the cell lead may be coupled to the bus bar in the third direction.

[0014] In some embodiments, the bus bar may be electrically coupled to the second portion by welding in the third direction.

[0015] In some embodiments, the wiring substrate includes a printed circuit board (PCB), and the bus bars may be secured to the PCB by a hook structure or heat fusion.

[0016] In some embodiments, the PCB includes conductive lines extending along a surface of the PCB, and the conductive lines may be electrically coupled to a plurality of bus bars.

[0017] In some embodiments, the battery cell includes a cell lead that protrudes toward the longitudinal beam, and a second portion of the cell lead that protrudes toward the longitudinal beam may extend to an upper portion of the longitudinal beam.

[0018] In some embodiments, the second portions of the cell leads protruding toward the longitudinal beams may be positioned to overlap the bus bars in the third direction.

[0019] In some embodiments, each of the pair of first outer walls includes an outer wall body extending in the first direction and a mesa portion protruding from the outer wall body toward an adjacent battery cell, and may further include an additional wiring structure on an upper portion of the mesa portion.

[0020] In some embodiments, the top surface of the mesa may be lower than the top surface of the outer wall body and may have the same height as the top surface of the longitudinal beam.

[0021] To achieve the second technical object, the present invention provides a method for manufacturing a battery pack, the method including: arranging a plurality of battery cells directly in a storage space of a pack case in a vertical coordinate system defined by a first direction, a second direction, and a third direction perpendicular to each other; and electrically connecting cell leads of at least two adjacent battery cells among the plurality of battery cells, the cell leads protruding in the second direction, using a bus bar. In this case, the pack case includes a pair of first outer walls extending in the first direction, a pair of second outer walls extending in the second direction and defining the internal space of the pack case together with the pair of first outer walls, and a longitudinal beam extending between the pair of first outer walls and parallel to the first outer walls. The step of electrically connecting the cell leads using the bus bar may include welding and connecting each of the cell leads to the bus bar in the third direction, and a wiring structure electrically connected to the plurality of battery cells may be provided on an upper portion of the longitudinal beam.

[0022] In some embodiments, the cell lead may include a first portion that is relatively close to the cover and a second portion that is relatively farther away from the cover, wherein the maximum dimension of the second portion in the first direction is greater than the maximum dimension of the first portion, and the second portion may be configured in a plane perpendicular to the third direction.

[0023] In some embodiments, the wiring structure may include a wiring board extending in the first direction along an upper surface of the longitudinal beam, and the bus bar coupled onto the wiring board.

[0024] In some embodiments, each of the pair of first outer walls includes an outer wall body extending in the first direction and a mesa portion protruding from the outer wall body toward an adjacent battery cell, and an additional wiring structure electrically connected to the plurality of battery cells may be provided on an upper portion of the mesa portion.

[0025] In some embodiments, the step of directly disposing the plurality of battery cells in the storage space of the pack case may include the step of attaching the plurality of battery cells to the lower case with an adhesive resin. [Effects of the Invention]

[0026] The battery pack and the manufacturing method thereof according to the embodiment of the present invention have the advantages of being able to be manufactured inexpensively using a simple number of parts, being excellent in productivity, and having little risk of product failure.

[0027] The effects that can be obtained from the exemplary embodiments of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood from the following description by a person having ordinary skill in the art to which the exemplary embodiments of the present disclosure belong. 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]

[0028] [Figure 1] 1 is an exploded perspective view showing a main part of a battery pack according to an embodiment of the present invention; [Figure 2] FIG. 2 is a perspective view showing a main part of a lower case of a pack case according to an embodiment of the present invention. [Figure 3] 3 is a side cross-sectional view showing a main part of the cross section of the battery pack of FIG. 1 taken along line III-III'. FIG. [Figure 4] 1 is a perspective view showing a main part of a battery cell according to an embodiment of the present invention. [Figure 5] 3 is a partially enlarged view showing a part of the battery cell, focusing on a cell lead portion of the battery cell according to an embodiment of the present invention; FIG. [Figure 6] 3 is a partially enlarged view of a part of the battery cell viewed from the x direction, with a cell lead portion of the battery cell at the center. FIG. [Figure 7]4 is a partially enlarged view of a part of the battery cell viewed from the y direction, with a cell lead portion of the battery cell at the center. FIG. [Figure 8] 3 is a partially enlarged view of a part of the battery cell viewed from the z direction, with a cell lead portion of the battery cell at the center. FIG. [Figure 9] FIG. 2 is a perspective view showing a pair of adjacent battery cells electrically connected by a bus bar. [Figure 10] 10 is a cross-sectional view showing a cross section of the second portion and the bus bar of FIG. 9 taken along line XX'. [Figure 11a] FIG. 2 is a plan view illustrating a connection relationship between battery cells according to an embodiment of the present invention. [Figure 11b] FIG. 2 is a plan view illustrating a connection relationship between battery cells according to an embodiment of the present invention. [Figure 11c] FIG. 2 is a plan view illustrating a connection relationship between battery cells according to an embodiment of the present invention. [Figure 12] 10 is a plan view illustrating a connection relationship between battery cells according to an additional embodiment of the present invention. FIG. [Figure 13] 10 is a plan view illustrating a connection relationship between battery cells according to an additional embodiment of the present invention. FIG. [Figure 14] 3 is a flowchart illustrating a method for manufacturing a battery pack according to an embodiment of the present invention. [Figure 15a] 1 is a perspective view illustrating a method for manufacturing a battery pack according to an embodiment of the present invention. [Figure 15b] 1 is a perspective view illustrating a method for manufacturing a battery pack according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] 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 may be modified in 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 of ordinary skill in the art. The same reference numerals refer to the same elements throughout. Furthermore, various elements and regions in the drawings are depicted schematically. Therefore, the inventive concept is not limited by the relative sizes or spacings depicted in the accompanying drawings.

[0030] 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.

[0031] 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. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, expressions such as "comprise" and "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.

[0032] 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, it is understood that terms defined in commonly used dictionaries should be interpreted to have a meaning consistent with what they mean in the context of the relevant art, and should not be interpreted as overly formal unless explicitly defined herein.

[0033] In other embodiments, the order of certain steps may be different from that described, for example, two steps described in succession may be performed substantially simultaneously or may be performed in the reverse order from that described.

[0034] In the accompanying drawings, variations in the shapes illustrated may be expected due to, for example, manufacturing techniques and / or tolerances. Therefore, embodiments of the present invention should not be construed as limited to the specific shapes of regions illustrated 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 listed 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.

[0035] 1 is an exploded perspective view showing a main part of a battery pack 10 according to one embodiment of the present invention. In FIG. 1, the battery pack 10 is shown as being defined in a vertical coordinate system in which a first direction is perpendicular to one another and is along the x-axis, a second direction is along the y-axis, and a third direction is along the z-axis. However, the first, second, and third directions are not particularly limited as long as they are relatively perpendicular to one another.

[0036] Referring to FIG. 1, the battery pack 10 includes a plurality of battery cells 100 stacked in a first direction (eg, x-axis direction) and a pack case 300 that houses the plurality of battery cells 100.

[0037] The pack case 300 has an interior space 330 that can accommodate the plurality of battery cells 100. In some embodiments, the pack case 300 can include an upper case 310 and a lower case 320 that define the interior space 330.

[0038] Although not explicitly shown in FIG. 1, the pack case 300 may be provided with conductors that electrically connect the plurality of battery cells 100 to an external electric load.

[0039] In some embodiments, the lower case 320 may have a box shape with an open top, and may accommodate a number of battery cells in the internal space 330. The upper case 310 may be configured as a lid that covers the open top of the lower case 320. In this case, the upper case 310 may be configured as a box shape with an open bottom.

[0040] The pack case 300 may include a plastic or metal material, or may be made of various exterior materials of battery packs known at the time of filing of the present invention.

[0041] The battery pack 10 may further include a battery management system. The battery management system (BMS) may be installed in the internal space of the pack case 300 and configured to generally control the charging and discharging operations and data transmission and reception operations of the battery cells 100. The battery management system may be provided on a pack-by-pack basis rather than on a module-by-module basis. More specifically, the battery management system may be configured to control the charging and discharging state, power state, and performance state of the battery cells 100 via the pack voltage and pack current.

[0042] The battery pack 10 may further include a battery disconnect unit, as shown in Fig. 1. The battery disconnect unit (BDU) may be configured to control electrical connection of battery cells to manage the power capacity and functions of the battery pack 10. To this end, the battery disconnect unit may include a power relay, a current sensor, a fuse, etc. The battery disconnect unit is also configured to be provided on a pack-by-pack basis rather than on a module-by-module basis, and various disconnection units known at the time of filing of the present invention may be used.

[0043] In addition, the battery pack 10 may further include various battery pack components known at the time of filing of the present invention. For example, the battery pack 10 according to an embodiment of the present invention may further include a manual service disconnector (MSD) that allows an operator to manually disconnect the service plug to cut off the power supply.

[0044] Fig. 2 is a perspective view showing a main part of a lower case 320 of a pack case 300 according to one embodiment of the present invention. Fig. 3 is a side cross-sectional view showing a main part of a cross section of the battery pack 10 of Fig. 1 taken along line III-III'.

[0045] 1 to 3, the lower case 320 includes a pair of first outer walls 321 extending in the first direction (e.g., x-axis direction). The lower case 320 also includes a pair of second outer walls 322 extending in the second direction (e.g., y-axis direction) and defining an internal space 330 of the pack case 300 together with the pair of first outer walls 321. In some embodiments, the first outer wall 321 and the second outer wall 322 may be integral with each other.

[0046] The lower case 320 further includes a longitudinal beam 323 extending between and parallel to the pair of first outer walls 321. The longitudinal beam 323 may extend in the first direction (e.g., the x-axis direction) and contact the pair of second outer walls 322. In some embodiments, the longitudinal beam 323 may be integral with the second outer wall 322.

[0047] In some embodiments, the longitudinal beam 323 may have a mesa structure. In some embodiments, the upper surface of the longitudinal beam 323 may be lower than the upper surface of the second outer wall 322. In some embodiments, the sidewall of the longitudinal beam 323 may extend diagonally downward relative to the upper surface. In other embodiments, the sidewall of the longitudinal beam 323 may extend perpendicular to the upper surface. In some embodiments, the sidewall of the longitudinal beam 323 may be configured to correspond to the edge shape of the adjacent battery cell 100.

[0048] The longitudinal beams 323 may define, together with adjacent ones of the first outer walls 321, an internal space 330 in which the battery cells 100 may be accommodated.

[0049] In some embodiments, the lower case 320 may include two or more longitudinal beams 323. In some embodiments, the pack case 300 may include two or more longitudinal beams 323. When the lower case 320 includes two or more longitudinal beams 323, two adjacent longitudinal beams 323 may define an additional interior space in which battery cells 100 can be accommodated.

[0050] Each of the pair of first outer walls 321 may include an outer wall main body 3211 extending in the first direction (e.g., the x-axis direction) and a mesa portion 3212 protruding from the outer wall main body 3211 toward the battery cell 100 adjacent to the outer wall main body 3211.

[0051] The mesa portion 3212 may extend in the first direction (e.g., the x-axis direction) and contact the pair of second outer walls 322. In some embodiments, the mesa portion 3212 may be integral with the outer wall main body 3211 and / or the second outer wall 322.

[0052] An upper surface of the mesa portion 3212 may be lower than an upper surface of the second outer wall 322. In some embodiments, the upper surface of the mesa portion 3212 may be flush with an upper surface of the longitudinal beam 323. In some embodiments, the width of the upper surface of the mesa portion 3212 may be narrower than the width of the upper surface of the longitudinal beam 323.

[0053] In some embodiments, the sidewalls of the mesa 3212 may extend diagonally downward relative to the top surface thereof. In other embodiments, the sidewalls of the mesa 3212 may extend perpendicular to the top surface thereof. In some embodiments, the sidewalls of the mesa 3212 may be configured to correspond to the edge shape of an adjacent battery cell 100.

[0054] A wiring structure 350 may be provided on an upper surface of the vertical beam 323. The wiring structure 350 may be any structure that electrically connects the battery cells 100 to each other. In some embodiments, the wiring structure 350 may include a wiring board 352 extending in the first direction (e.g., the x-axis direction) along the vertical beam 323. The wiring board 352 may include an insulating layer and any conductive lines formed on the insulating layer.

[0055] In some embodiments, the wiring structure 350 may further include a bus bar 200 on the wiring substrate 352. The bus bar 200 may be any conductor that electrically connects two battery cells 100 adjacent to each other in the first direction (e.g., the x-axis direction), as will be described in more detail later.

[0056] In some embodiments, the cell leads 110 of the battery cell 100 that protrude toward the longitudinal beam 323 may extend to an upper portion of the longitudinal beam 323. Specifically, the second portions 112 of the cell leads 110 that protrude toward the longitudinal beam 323 may extend to an upper portion of the longitudinal beam 323. Furthermore, the second portions 112 of the cell leads 110 that protrude toward the longitudinal beam 323 may be coupled to the bus bar 200 at the upper portion of the longitudinal beam 323 in a third direction (e.g., the z-axis direction).

[0057] In some embodiments, an additional wiring structure 350 may be provided on the upper surface of the mesa portion 3212 of the first outer wall 321. The wiring structure 350 on the mesa portion 3212 may also include a wiring substrate 352 and a bus bar 200.

[0058] The lower case 320 further includes a bottom 326. The bottom 326 is provided below the pair of first outer walls 321, the pair of second outer walls 322, and the longitudinal beam 323. In some embodiments, the bottom 326 may be integral with one or more of the pair of first outer walls 321, the pair of second outer walls 322, and the longitudinal beam 323.

[0059] The battery cell 100 may be bonded to the lower case 320 by an adhesive resin 328. Any material having thermal conductivity and adhesive properties may be used as the adhesive resin 328. In some embodiments, the adhesive resin 328 may include an acrylic resin, a urethane resin, a silicone resin, or a mixture thereof.

[0060] The thickness of the adhesive resin 328 may be about 0.8 mm to about 1.2 mm. If the thickness of the adhesive resin 328 is too thin, it is difficult to expect sufficient heat dissipation effect and fixing strength. If the thickness of the adhesive resin 328 is too thick, the effect saturates compared to the increased cost, which is economically disadvantageous.

[0061] FIG. 4 is a perspective view showing a main part of a battery cell 100 according to one embodiment of the present invention.

[0062] Referring to FIG. 4, the battery cell 100 includes an electrode assembly 101, a cover 105 surrounding the electrode assembly 101, and a cell lead 110 protruding from one side of the cover 105 in the second direction (e.g., the y direction).

[0063] In some embodiments, the battery cell 100 may be a pouch-type battery cell, but the present invention is not limited thereto. In some embodiments, the battery cell 100 may be a prismatic battery cell.

[0064] In some embodiments, the battery cell 100 has a thin plate-like body, preferably a pouch cell. The pouch cell may have a structure in which a positive electrode, a separator, and a negative electrode are alternately stacked to form the electrode assembly 101, with an electrode tab extending from at least one side and connected to the cell lead 110. The positive and negative electrodes may be fabricated by coating at least one surface of a current collector with a slurry containing an electrode active material, a binder resin, a conductive material, and other additives. The positive electrode may use a conventional positive electrode active material, such as a lithium-containing transition metal oxide, while the negative electrode may use a conventional negative electrode active material, such as lithium metal, a carbon material, a metal compound, or a mixture thereof, capable of absorbing and releasing lithium ions. The separator may be a conventional porous polymer film used in lithium secondary batteries.

[0065] A typical electrolyte for lithium secondary batteries may be used as the electrolyte housed in the cover 105 together with the electrode assembly 101. The cover 105 is made of a sheet material and includes a housing for housing the electrode assembly 101. Preferably, the cover 105 is formed by combining a first case and a second case, each of which is formed by processing the sheet material into a predetermined shape. The sheet material constituting the cover 105 has a multilayer structure including an outermost resin layer made of an insulating material such as polyethylene terephthalate (PET) or nylon, a metal layer made of aluminum that maintains mechanical strength and prevents penetration of moisture and oxygen, and an inner resin layer made of a polyolefin-based material that has thermal adhesive properties and serves as a sealant.

[0066] The sheet material forming the cover 105 may have a predetermined adhesive resin layer interposed between the inner resin layer and the metal layer, and between the outer resin layer and the metal layer, as needed. The adhesive resin layer is formed as a single layer or multiple layers to facilitate smooth adhesion between different materials. Polyolefin resins are typically used as the material, or polyurethane resins for easy processing, and mixtures thereof may also be used.

[0067] 4, the battery cell 100 has two major surfaces S1 and S2 perpendicular to the first direction (e.g., the x direction). That is, the battery cell 100 may have a first major surface S1 and a second major surface S2 extending along the yz plane in FIG. 4 and parallel to each other.

[0068] FIG. 5 is a partially enlarged view showing a part of the battery cell 100, focusing on the cell lead 110 of the battery cell 100 according to one embodiment of the present invention.

[0069] 5, the cell lead 110 protrudes from one side of the cover 105 in the second direction (e.g., the y-axis direction) and includes a first portion 111 and a second portion 112. The first portion 111 may be located closer to the cover 105 than the second portion 112. The second portion 112 may be the tip of the cell lead 110 in the second direction.

[0070] The first portion 111 and the second portion 112 may be electrically connected to each other. In some embodiments, the first portion 111 and the second portion 112 may be in direct contact with each other, but the present invention is not limited thereto. In some embodiments, the first portion 111 and the second portion 112 may be integrally formed (integrated).

[0071] In some embodiments, the first portion 111 may have the form of a flat plate having a plane perpendicular to the first direction (e.g., the x-axis direction) as a main plane. In some embodiments, the second portion 112 may be configured as a plane perpendicular to the third direction (e.g., the z-axis direction). Here, the second portion 112 being configured as a plane perpendicular to the third direction means that the upper and lower surfaces of the second portion 112 are perpendicular to the third direction but do not include through-holes therein. In some embodiments, the upper and lower surfaces of the second portion 112 may be perpendicular to the third direction but may not include through-holes therein. In some embodiments, the upper and lower surfaces of the second portion 112 may be perpendicular to the third direction but may include through-holes therein.

[0072] FIG. 6 is a partially enlarged view of a part of the battery cell 100 viewed from the x direction, with the cell lead 110 of the battery cell 100 at the center.

[0073] 6, the first portion 111 of the cell lead 110 has a first upper surface 111a and a first lower surface 111b. The second portion 112 of the cell lead 110 has a second upper surface 112a and a second lower surface 112b. Here, the terms "upper surface" and "lower surface" are relative concepts, and one located relatively higher can be defined as the "upper surface" and one located relatively lower as the "lower surface," or one of the two can be defined as the "upper surface" and the other as the "lower surface."

[0074] A center line CL may be defined for the first portion 111. The center line CL is a straight line in a second direction (for example, the y-axis direction) that divides the first portion 111 into two equal parts in a third direction (for example, the z-axis direction).

[0075] In the third direction, the center line CL may be located between the second upper surface 112a and the second lower surface 112b of the second portion 112.

[0076] In the third direction, the first portion 111 has a first dimension H1, and the second portion 112 has a second dimension H2 that is smaller than the first dimension H1. The second dimension H2 may be, for example, about 0.5% to about 50% of the first dimension H1. In some embodiments, the second dimension H2 may be approximately 0.5% to approximately 50%, approximately 1% to approximately 48%, approximately 1.5% to approximately 45%, approximately 2% to approximately 43%, approximately 2.5% to approximately 40%, approximately 3% to approximately 38%, approximately 3.5% to approximately 35%, approximately 4% to approximately 33%, approximately 4.5% to approximately 30%, approximately 5% to approximately 28%, approximately 5.5% to approximately 25%, approximately 6% to approximately 23%, approximately 6.5% to approximately 20%, approximately 7% to approximately 18%, approximately 7.5% to approximately 15%, approximately 8% to approximately 13%, approximately 8.5% to approximately 10% of the first dimension H1, or a range between any two of these values.

[0077] If the second dimension H2 is too small compared to the first dimension H1, the second portion 112 may have insufficient mechanical strength and may be easily damaged. If the second dimension H2 is too large compared to the first dimension H1, the weight of the battery cell 100 may increase unnecessarily.

[0078] FIG. 7 is a partially enlarged view of a part of the battery cell 100 viewed from the y direction, with the cell lead 110 of the battery cell 100 at the center.

[0079] 7, in a first direction (e.g., the x-axis direction), the first portion 111 of the cell lead 110 has a first maximum dimension d1, and the second portion 112 of the cell lead 110 has a second maximum dimension d2. The second maximum dimension d2 is greater than the first maximum dimension d1. For example, the second maximum dimension d2 may be about 2 to 20 times the first maximum dimension d1. In some embodiments, the second maximum dimension d2 may be about 2 to about 20 times, about 2.5 to about 19.5 times, about 3 to about 19 times, about 3.5 to about 18.5 times, about 4 to about 18 times, about 4.5 to about 17.5 times, about 5 to about 17 times, about 5.5 to about 16.5 times, about 6 to about 16 times, about 6.5 to about 15.5 times, about 7 to about 15 times, about 7.5 to about 14.5 times, about 8 to about 14 times, about 8.5 to about 13.5 times, about 9 to about 13 times, about 9.5 to about 12.5 times, about 10 to about 12 times, or about 10.5 to about 11.5 times the first maximum dimension d1, or may be in a range between any two of these values.

[0080] If the second maximum dimension d2 is too small compared to the first maximum dimension d1, it may not be easy to weld a bus bar (described later) to the second portion 112. If the second maximum dimension d2 is too large compared to the first maximum dimension d1, the thickness of the battery cell 100 in a first direction (e.g., the x-axis direction) may increase excessively, and the energy density may decrease.

[0081] In some embodiments, a second maximum dimension d2 of the second portion 112 in a first direction (e.g., the x-axis direction) may be greater than a cell thickness d3 defined between the first major surface S1 and the second major surface S2 of the battery cell 100. In other embodiments, the second maximum dimension d2 of the second portion 112 in the first direction (e.g., the x-axis direction) may be smaller than a cell thickness d3 defined between the first major surface S1 and the second major surface S2 of the battery cell 100.

[0082] FIG. 8 is a partially enlarged view of a part of the battery cell 100 viewed from the z direction, with the cell lead 110 of the battery cell 100 at the center.

[0083] 8, a projection of the second portion 112 on a plane (e.g., an xy plane) perpendicular to the third direction (e.g., the z-axis direction) may have a circular shape. In some embodiments, the projection of the second portion 112 on the xy plane may have any shape other than a circle, such as an ellipse, a polygon (e.g., a square, a pentagon, a hexagon, etc.), or any other shape. However, it may be advantageous for the projection to have a circular shape in terms of the versatility of welding methods that can be used for subsequent welding to a bus bar, structural stability, ease of handling, etc.

[0084] In some embodiments, when the projection is circular, the second portion 112 may have the form of a cylinder or a truncated cone. When the projection is polygonal, the second portion 112 may have the form of a polygonal prism or a truncated pyramid.

[0085] The projected area of ​​the second portion 112 may be about 2 to about 20 times the projected area of ​​the first portion 111. In some embodiments, the projected area of ​​the second portion 112 may be about 2 to about 20 times, about 2.5 to about 19 times, about 3 to about 18 times, about 3.5 to about 17 times, about 4 to about 16 times, about 4.5 to about 15 times, about 5 to about 14 times, about 5.5 to about 13 times, about 6 to about 12 times, about 6.5 to about 11 times, about 7 to about 10 times, about 7.5 to about 9 times the projected area of ​​the first portion 111, or a range between any two of these values.

[0086] If the projected area of ​​the second portion 112 is too small compared to the projected area of ​​the first portion 111, it may not be easy to weld a bus bar (to be described later) to the second portion 112. If the projected area of ​​the second portion 112 is too large compared to the projected area of ​​the first portion 111, the weight of the battery cell 100 may increase unnecessarily.

[0087] The second portions 112 of the cell leads 110 of the battery cells 100 have a planar shape perpendicular to the third direction (e.g., the z-axis direction), and therefore, the battery cells 100 can be electrically interconnected after being coupled to the pack case 300. Therefore, the battery pack according to the embodiment of the present invention has a simple number of parts, can be manufactured at low cost, has excellent productivity, and has little risk of product failure.

[0088] FIG. 9 is a perspective view showing a pair of adjacent battery cells 100_1 and 100_2 electrically connected by a bus bar 200. As shown in FIG.

[0089] Referring to FIG. 9, the cell lead 110_1 of the first battery cell 100_1 includes a first portion 111_1 and a second portion 112_1, and the cell lead 110_2 of the second battery cell 100_2 includes a first portion 111_2 and a second portion 112_2.

[0090] The cell lead 110_1 of the first battery cell 100_1 and the cell lead 110_2 of the second battery cell 100_2 may be electrically connected by a bus bar 200. Specifically, the second portion 112_1 of the first battery cell 100_1 and the second portion 112_2 of the second battery cell 100_2 may be electrically connected by the bus bar 200.

[0091] The cell lead 110_1 of the first battery cell 100_1 and the cell lead 110_2 of the second battery cell 100_2, which are electrically connected by the bus bar 200, may have the same polarity or different polarities.

[0092] The bus bar 200 may be disposed to extend in a first direction (e.g., the x-axis direction) and may be configured to contact the lower surfaces of the second portion 112_1 of the first battery cell 100_1 and the second portion 112_2 of the second battery cell 100_2. In some embodiments, the bus bar 200 may have a strip shape extending in the first direction. In this case, a flat surface of the bus bar 200 may face the second portion 112_1 of the first battery cell 100_1 and the second portion 112_2 of the second battery cell 100_2 in a third direction (e.g., the z-axis direction).

[0093] The bus bar 200 may be provided on a wiring substrate 352 disposed on top of the longitudinal beam 323, as described with reference to Figures 2 and 3. In some embodiments, the bus bar 200 may be provided on a wiring substrate 352 disposed on top of the mesa portion 3212, as described with reference to Figures 2 and 3.

[0094] The cell lead 110_1 of the first battery cell 100_1 and the cell lead 110_2 of the second battery cell 100_2 may extend to an upper portion of the vertical beam 323. Specifically, the cell lead 110_1 of the first battery cell 100_1 and the cell lead 110_2 of the second battery cell 100_2 may be electrically connected to the bus bar 200 at an upper portion of the vertical beam 323.

[0095] FIG. 10 is a cross-sectional view showing a cross section of second portions 112_1 and 112_2 and bus bar 200 taken along line XX' in FIG.

[0096] 10 , the bus bar 200 may have a recess R recessed in a third direction (e.g., the z-axis direction) at a portion overlapping with the second portions 112_1 and 112_2. In some embodiments, the recess R may be generated as a result of welding the bus bar 200 and the second portions 112_1 and 112_2 in the third direction. However, since the recess R is a result of partial melting and solidification of contact portions between the bus bar 200 and the second portions 112_1 and 112_2 due to welding, it may appear as a trace of melting and solidification in some cases.

[0097] In FIG. 10, the recess R is shown as being formed continuously with the flat surface of the bus bar 200, but in some cases, a slight protrusion may be formed around the recess R.

[0098] In some embodiments, due to the welding method, the recess R may not be observed as a clear interface.

[0099] 11a to 11c are plan views showing the connection relationship of the battery cell 100 according to the embodiment of the present invention.

[0100] 11a, a plurality of battery cells 100 may be stacked and arranged in the first direction (e.g., the x-axis direction). In some embodiments, heat dissipation pads that reduce heat transfer between the battery cells 100 may be further provided between the plurality of battery cells 100. In some embodiments, a portion of a cartridge that individually houses the battery cells 100 may be inserted between the plurality of battery cells 100.

[0101] The plurality of battery cells 100 may be electrically connected to one another by bus bars 200. In some embodiments, the plurality of battery cells 100 may be connected in series. That is, the cathode of one battery cell 100 may be connected to the anode of an adjacent battery cell via the bus bars 200. In some embodiments, the plurality of battery cells 100 may be connected one by one by the bus bars 200 in a zigzag pattern.

[0102] 11a, the cell lead 110 of the battery cell 100 protrudes in a second direction (e.g., the y-axis direction), and the second portion 112 of the cell lead 110 is arranged to overlap a bus bar 200 extending in a first direction (e.g., the x-axis direction) in a third direction (e.g., the z-axis direction). The cell lead 110 and the bus bar 200 may be interconnected by welding in the third direction (e.g., the z-axis direction). The bus bar 200 extending in the first direction (e.g., the x-axis direction) may be connected to the cell lead 110 of another adjacent battery cell 100 in the same manner.

[0103] Fig. 12 is a plan view showing a connection relationship of a battery cell 100 according to an additional embodiment of the present invention. The embodiment shown in Fig. 12 is substantially the same as the embodiment shown in Fig. 11a, except that the bus bar 200 is provided on a printed circuit board (PCB) 352. Therefore, the following description will focus on these differences and omit redundant description.

[0104] 12 , the bus bar 200 may be provided on one surface of the PCB 352. In some embodiments, the bus bar 200 may be supported by the PCB 352. In some embodiments, the bus bar 200 may be fixed onto the PCB 352. In some embodiments, the bus bar 200 may be fixed onto the PCB 352 by a hook structure or heat fusion. However, the present invention is not limited thereto.

[0105] The bus bar 200 provided on the PCB 352 may be electrically connected to a conductive line 355 extending along the surface of the PCB 352. The conductive line 355 may be made of any metal material with low electrical resistance, and is not particularly limited.

[0106] The shape of the conductive lines 355 shown in FIG. 12 is merely intended to show that they extend along the surface of the PCB 352, and the present invention is not necessarily limited to the connection relationship shown in FIG.

[0107] The conductive line 355 may be electrically connected to a connector 357 that electrically connects the battery cell 100 to an external load. The connector 357 may be provided directly on the PCB 352 or may be provided separately from the PCB 352.

[0108] 11b, which is another embodiment of the present invention, the plurality of battery cells 100 may include a first group G1 of battery cells 100, a second group G2 of battery cells 100, a third group G3 of battery cells 100, ..., and an n-th group Gn of battery cells 100. The battery cells 100 in the same group may have the same anode and cathode orientations.

[0109] 11b, the anodes 110a and cathodes 110c of the battery cells 100 of the first group G1 may be aligned in a straight line. Also, the anodes 110a and cathodes 110c of the battery cells 100 of the second group G2 adjacent to the battery cells 100 of the first group G1 may be aligned in a straight line. In some embodiments, the cathodes 110c of the battery cells 100 of the first group G1 may be aligned in a straight line with the anodes 110a of the battery cells 100 of the second group G2, and they may be electrically connected to each other by one bus bar 200.

[0110] In addition, the anodes 110a and cathodes 110c of the battery cells 100 of the third group G3 adjacent to the battery cells 100 of the second group G2 may be aligned in a straight line. In some embodiments, the cathodes 110c of the battery cells 100 of the second group G2 may be aligned in a straight line with the anodes 110a of the battery cells 100 of the third group G3, and they may be electrically connected to each other by one bus bar 200.

[0111] The battery cells 100 of the first group G1, the battery cells 100 of the second group G2, the battery cells 100 of the third group G3, . . . and the battery cells 100 of the n-th group Gn may be arranged in the first direction (for example, the x-axis direction).

[0112] The embodiment shown in FIG. 11c is substantially the same as the embodiment shown in FIG. 11b, except that three battery cells are included in one group.

[0113] 11c, the anodes 110a and cathodes 110c of the battery cells 100 of the first group G1 may be aligned in a straight line. Also, the anodes 110a and cathodes 110c of the battery cells 100 of the second group G2 adjacent to the battery cells 100 of the first group G1 may be aligned in a straight line. In some embodiments, the anodes 110a of the battery cells 100 of the first group G1 may be aligned in a straight line with the cathodes 110c of the battery cells 100 of the second group G2, and they may be electrically connected to each other by one bus bar 200.

[0114] 11b and 11c, even when two or more battery cells 100 are connected in parallel as a group, the cell leads 110 do not need to be bent, which can significantly improve component reliability. Furthermore, the number of components can be reduced because the batteries can be connected by simply connecting them to bus bars arranged on a substrate such as a PCB. Therefore, the battery pack according to the embodiment of the present invention can be manufactured with a simple number of components at low cost, has excellent productivity, and reduces concerns about product failure.

[0115] FIG. 13 is a plan view showing a connection relationship of a battery cell 100 according to a further embodiment of the present invention.

[0116] 13, the plurality of battery cells 100 include a first cell stack ST1 and a second cell stack ST2 that are stacked and arranged in a first direction (e.g., x-axis direction). The battery cells 100 of the first cell stack ST1 extend in the second direction (e.g., y-axis direction) and include cell leads 110 at both ends in the second direction (e.g., y-axis direction). The battery cells 100 of the second cell stack ST2 extend in the second direction (e.g., y-axis direction) and include cell leads 110 at both ends in the second direction (e.g., y-axis direction).

[0117] The first cell stack ST1 and the second cell stack ST2 may be disposed at a predetermined interval in a second direction (e.g., y-axis direction). Cell leads 110 on one side of the battery cells of the first cell stack ST1 may face the second cell stack ST2 and may be connected to each other by a first bus bar 200a. Cell leads 110 on one side of the battery cells of the second cell stack ST2 may face the first cell stack ST1 and may be connected to each other by a second bus bar 200b.

[0118] In some embodiments, the first cell stack ST1 and the second cell stack ST2 may share one PCB 352 for electrical connection of the battery cells 100 of the first cell stack ST1 and the battery cells 100 of the second cell stack ST2.

[0119] The first bus bar 200a and the second bus bar 200b may be arranged on one PCB 352. In some embodiments, the first bus bar 200a may be arranged in a row along one edge of the PCB 352, and the second bus bar 200b may be arranged in a row along the other edge of the PCB 352. In some embodiments, the first bus bar 200a and the second bus bar 200b may be arranged parallel to each other.

[0120] The battery cells 100 of the first cell stack ST1 and the second cell stack ST2 can be electrically connected to each other after the battery cells 100 are coupled to the pack case 300 because the second portions 112 of the cell leads 110 have a planar shape perpendicular to the third direction (e.g., the z-axis direction). Therefore, the battery pack according to the embodiment of the present invention can be manufactured inexpensively with a simple number of parts, has excellent productivity, and reduces concerns about product failure.

[0121] Fig. 14 is a flowchart showing a method for manufacturing the battery pack 10 according to one embodiment of the present invention. Fig. 15a and Fig. 15b are perspective views showing a method for manufacturing the battery pack 10 according to one embodiment of the present invention.

[0122] 14 and 15a, a plurality of battery cells 100 may be directly disposed in a pack case 300 (S10). Here, disposing the plurality of battery cells 100 directly in the pack case 300 means disposing the plurality of battery cells 100 in the pack case 300 without configuring them as a module.

[0123] In some embodiments, the plurality of battery cells 100 may be individually disposed one by one in the pack case 300. In other embodiments, the plurality of battery cells 100 may be disposed in the pack case 300 after being stacked two or more times.

[0124] Before the plurality of battery cells 100 are disposed in the pack case 300, a layer of adhesive resin 328 may be formed on the bottom of the lower case 320 of the pack case 300. The adhesive resin 328 may include, for example, an acrylic resin, a urethane resin, a silicone resin, or a mixture thereof. The thickness of the layer of adhesive resin 328 may be about 0.8 mm to about 1.2 mm. The layer of adhesive resin 328 may be formed at a position where the plurality of battery cells 100 will be disposed.

[0125] Thereafter, the battery cell 100 may be placed directly into the lower case 320 so that the edge of the battery cell 100 facing the bottom of the lower case 320 contacts the layer of the adhesive resin 328 .

[0126] The method for arranging the battery cells 100 in the pack case 300 is not particularly limited, and the battery cells 100 may be arranged in the pack case 300 by any known method. The configuration of the lower case 320 has been described with reference to Figures 1 to 3, so a detailed description thereof will be omitted here. In addition, the specific configuration of each battery cell 100 has been described with reference to Figures 4 to 10, so a detailed description thereof will be omitted here.

[0127] 14 and 15b, the cell leads 110_1 and 110_2 protruding in a second direction (e.g., the y-axis direction) of two adjacent battery cells 100 may be electrically connected to the bus bar 200 (S20). The cell leads 110_1 and 110_2 may be connected to the bus bar 200 by welding in a third direction (e.g., the z-axis direction).

[0128] In some embodiments, the bus bar 200 may be disposed in the pack case 300 before the plurality of battery cells 100 are disposed in the pack case 300. In some embodiments, the bus bar 200 may be disposed on the cell leads 110_1, 110_2 after the plurality of battery cells 100 are disposed in the pack case 300. Thereafter, the bus bar 200 may be welded to the cell leads 110_1, 110_2. Any known welding method may be adopted and is not particularly limited.

[0129] The second portions 112 of the cell leads 110 of the battery cells 100 have a planar shape perpendicular to the third direction (e.g., the z-axis direction), and therefore, the battery cells 100 can be electrically interconnected after being coupled to the pack case 300. Therefore, the battery pack according to the embodiment of the present invention has a simple number of parts, can be manufactured at low cost, has excellent productivity, and has little risk of product failure.

[0130] Thereafter, the upper case 310 may be coupled to the lower case 320 to cover the battery cell 100 .

[0131] As described above, in the battery pack 10 according to an embodiment of the present invention, the cell leads 110 of the battery cells 100 are arranged to overlap with the bus bars 200 arranged on the pack case 300, particularly the lower case 320, in the third direction (e.g., z-axis direction), and electrical connection is completed by simple welding in the third direction (e.g., z-axis direction). This allows for a simple and inexpensive manufacture with a high number of parts, excellent productivity, and reduced concerns about product failure.

[0132] Although the embodiments of the present invention have been described in detail as described 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 will not depart from the technology of the present invention. [Explanation of symbols]

[0133] 10 Battery Pack 100 battery cells 100_1 1st battery cell 100_2 Second battery cell 101 Electrode assembly 105 Cover 110 Cell Read 110_1 Cell Read 110_2 Cell Read 110a anode 110c cathode 111 Part 1 111_1 Part 1 111_2 Part 1 111a 1st top surface 111b 1st bottom surface 112 Part 2 112_1 2nd part 112_2 2nd part 112a 2nd top surface 112b 2nd bottom surface 200 Busbar 200a 1st bus bar 200b Second bus bar 300 pack case 310 Upper Case 320 Lower Case 321 1st outer wall 322 Second outer wall 323 Longitudinal Beam 326 Bottom 328 Adhesive resin 330 Interior Space 350 Wiring structure 352 Wiring board 355 Conductive Line 357 Connector 3211 Exterior wall body 3212 Mesa CL center line d1 First maximum dimension d2 Second largest dimension G1 1st Group G2 2nd Group G3 3rd Group Gn nth group H1 First dimension H2 Second dimension R recess S1 1st main surface S2 2nd main surface ST1 First cell stack ST2 Second cell stack

Claims

1. In a vertical coordinate system defined by a first direction, a second direction, and a third direction that are perpendicular to each other, a plurality of battery cells stacked in the first direction; a pack case including an internal space that accommodates the plurality of battery cells; a wiring structure provided on the pack case, each of at least two adjacent battery cells among the battery cells includes an electrode assembly, a cover surrounding the electrode assembly, and a cell lead protruding in the second direction from one side of the cover; the cell lead includes a first portion relatively close to the cover and a second portion relatively farther away from the cover; The pack case is a pair of first outer walls extending in the first direction; a pair of second outer walls extending in the second direction and defining an internal space of the pack case together with the pair of first outer walls; a longitudinal beam extending between the pair of first outer walls and parallel to the first outer walls; the wiring structure includes a wiring substrate and a plurality of bus bars extending in the first direction on the wiring substrate; Each of the bus bars is configured to electrically connect adjacent second portions to each other by extending in the first direction.

2. The battery pack according to claim 1 , wherein the wiring structure is provided on an upper surface of the longitudinal beam.

3. the cell lead is configured such that a maximum dimension of the second portion is greater than a maximum dimension of the first portion in the first direction; The battery pack according to claim 1 , wherein the second portion of the cell lead is coupled to the bus bar in the third direction.

4. The battery pack according to claim 3 , wherein the bus bar is electrically connected to the second portion by welding in the third direction.

5. the wiring board includes a printed circuit board (PCB); The battery pack according to claim 1 or 2, wherein the bus bars are fixed to the PCB by a hook structure or heat fusion.

6. the PCB includes conductive lines extending along a surface of the PCB; The battery pack according to claim 5 , wherein the conductive lines are electrically connected to a plurality of bus bars.

7. The battery cell includes a cell lead protruding toward the longitudinal beam, 3. The battery pack according to claim 1, wherein the second portion of the cell lead protruding toward the longitudinal beam extends to an upper portion of the longitudinal beam.

8. 8. The battery pack according to claim 7, wherein the second portions of the cell leads protruding toward the longitudinal beams are arranged to overlap the bus bars in the third direction.

9. Each of the pair of first outer walls is an outer wall body extending in the first direction; a mesa portion protruding from the outer wall body toward an adjacent battery cell, The battery pack according to claim 1 or 2, further comprising an additional wiring structure on top of the mesa portion.

10. The battery pack according to claim 9 , wherein an upper surface of the mesa portion is lower than an upper surface of the outer wall body and has the same height as an upper surface of the longitudinal beam.

11. In a vertical coordinate system defined by a first direction, a second direction, and a third direction that are perpendicular to each other, placing a plurality of battery cells directly within an interior space of a pack case; electrically connecting cell leads protruding in the second direction of at least two adjacent battery cells among the plurality of battery cells using a bus bar; The pack case is a pair of first outer walls extending in the first direction; a pair of second outer walls extending in the second direction and defining the internal space of the pack case together with the pair of first outer walls; a longitudinal beam extending between the pair of first outer walls and parallel to the first outer walls; the step of electrically connecting the cell leads to each other using a bus bar includes the step of welding each of the cell leads to the bus bar in the third direction to connect them, a wiring structure electrically connected to the plurality of battery cells is provided on an upper portion of the vertical beam.

12. the cell lead includes a first portion that is relatively close to a cover of the battery cell and a second portion that is relatively farther away from the cover; 12. The method of manufacturing a battery pack according to claim 11, wherein a maximum dimension of the second portion in the first direction is greater than a maximum dimension of the first portion, and the second portion is configured as a plane perpendicular to the third direction.

13. The wiring structure is a wiring board extending in the first direction along an upper surface of the longitudinal beam; The method for manufacturing a battery pack according to claim 11 or 12, further comprising:

14. Each of the pair of first outer walls is an outer wall body extending in the first direction; a mesa portion protruding from the outer wall body toward an adjacent battery cell, The method of manufacturing a battery pack according to claim 11 or 12, wherein an additional wiring structure electrically connected to the plurality of battery cells is provided on an upper portion of the mesa portion.

15. 13. The method for manufacturing a battery pack according to claim 11 or 12, wherein the step of directly disposing the plurality of battery cells in the internal space of the pack case includes the step of attaching the plurality of battery cells to a lower case of the pack case with an adhesive resin.

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