Battery pack and method for manufacturing same

Abstract

Provided is a battery pack including: a plurality of battery cells stacked in a first direction in a vertical coordinate system defined by the first direction, a second direction, and a third direction perpendicular to each other; and a pack case configured to accommodate a plurality of battery cells in an internal space, in which the pack case includes: a pair of first outer walls extending in a first direction; a pair of second outer walls extending in the second direction and defining an inner space of the pack case together with the pair of first outer walls; a longitudinal beam disposed between the pair of first outer walls and extending parallel to the pair of first outer walls; and a bottom portion disposed below the first outer wall, the second outer wall, and the longitudinal beam, the longitudinal beam being provided with a wiring structure and electrically connected to the plurality of battery cells, and a heat sink being disposed in the longitudinal beam.

Description

Technical Field

[0001] The present disclosure relates to a battery pack and a method of manufacturing the same, and more particularly, to a battery pack and a method of manufacturing the same that quickly remove heat generated inside to control an increase in internal temperature and improve safety.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0167136, filed on December 2, 2022, and Korean Patent Application No. 10-2023-0038228, filed on March 23, 2023, the entire contents of the foregoing Korean patent applications being incorporated herein by reference. Background Art

[0003] With the advancement of technologies of various types of mobile devices, electric vehicles, energy storage systems (ESSs), etc. and the growth in demand therefor, attention and demand for secondary batteries as an energy source are increasing rapidly. In the past, nickel-cadmium batteries or nickel-metal hydride batteries were often used as secondary batteries. However, recently, lithium secondary batteries have often been used because, compared to nickel-based secondary batteries, lithium secondary batteries have almost no memory effect, and thus can be freely charged and discharged and have a very low self-discharge rate and high energy density.

[0004] Generally, in such lithium secondary batteries, lithium-based oxides and carbon materials are used as a positive electrode active material and a negative electrode active material, respectively. The lithium secondary battery includes: an electrode assembly in which a positive electrode plate coated with a positive electrode active material and a negative electrode plate coated with a negative electrode active material are provided, and a separator is interposed between the positive electrode plate and the negative electrode plate; and an exterior material, that is, a battery case, for sealing and accommodating the electrode assembly and an electrolyte together.

[0005] Recently, battery packs have been widely used to drive medium- and large-sized devices (e.g., electric vehicles and energy storage systems) or store energy for them. In a conventional battery pack, one or more battery modules and a control unit for controlling charging and discharging of the battery pack, e.g., a battery management system (BMS), are included in a battery pack case. Here, one or more battery modules are each configured to include a plurality of battery cells inside a module case. That is, each battery module is formed by accommodating a plurality of battery cells (secondary batteries) in the module case, and at least one such battery module is accommodated in the battery pack case to form a conventional battery pack.

[0006] In particular, a pouch-type battery has advantages in various aspects. For example, a pouch-type battery is lightweight and has a small dead space when pouch-type batteries are stacked, but it is vulnerable to external impacts and its assemblability is low. Therefore, generally, a battery pack is manufactured by first modularizing a plurality of battery cells and accommodating the plurality of battery cells inside a battery pack housing. As a representative example, a battery module is formed by accommodating a plurality of pouch-type battery cells in a module housing, and at least one such battery module is accommodated in a battery pack housing to form a conventional battery pack.

[0007] However, such a conventional battery pack may be disadvantageous in terms of energy density. Generally, when a plurality of battery cells are modularized by accommodating them in a module housing, the volume of the battery pack may be unnecessarily increased or the space occupied by the battery cells may be reduced due to various components such as the module housing or the battery stack frame. In addition, the space for accommodating the battery cells may be reduced to ensure the assembly tolerance of such components and the space occupied by components such as the module housing or the battery stack frame. Therefore, in the case of a conventional battery pack, there may be limitations in increasing the energy density.

[0008] In addition, a conventional battery pack may be disadvantageous in terms of assemblability. In particular, to manufacture a battery pack, a battery module is configured by modularizing a plurality of battery cells and then accommodated in a battery pack housing, so the manufacturing process of the battery pack becomes complicated. Moreover, as disclosed in the above-mentioned related technical literature, the process of forming a battery cell stack using a battery stack frame, bolts, plates, etc. and the structure of the battery cell stack may be very complicated. Summary of the Invention

[0009] Technical Problem

[0010] A first technical aspect of the present disclosure aims to provide a battery pack that can quickly remove internally generated heat to control the rise of the internal temperature and improve safety.

[0011] A second technical aspect of the present disclosure aims to provide a method for manufacturing a battery pack that can quickly remove internally generated heat to control the rise of the internal temperature and improve safety.

[0012] Technical Solution

[0013] A first aspect of the present disclosure provides a battery pack, comprising: a plurality of battery cells, which are 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; and a battery pack housing configured to accommodate the plurality of battery cells in an internal space, wherein the battery pack housing 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 battery pack housing together with the pair of first outer walls; a longitudinal beam disposed between the pair of first outer walls and extending parallel to the pair of first outer walls; and a bottom disposed below the first outer walls, the second outer walls, and the longitudinal beam. A wiring structure is provided on the longitudinal beam and is electrically connected to the plurality of battery cells, and a radiator is provided in the longitudinal beam.

[0014] In some embodiments, the radiator may include channels for a cooling fluid extending in the first direction.

[0015] In some embodiments, an additional radiator may also be provided in the bottom below the plurality of battery cells. In some embodiments, no radiator may be provided in the bottom below the longitudinal beam.

[0016] In some embodiments, each battery cell may include an electrode assembly, a cover surrounding the electrode assembly, and a first battery cell lead protruding from one side of the cover to the upper part of the longitudinal beam in the second direction.

[0017] In some embodiments, the first battery cell lead may include a first portion relatively close to the cover and a second portion relatively far from the cover, and in the first direction, the maximum dimension of the second portion may be larger than the maximum dimension of the first portion, and the second portion may be a plane perpendicular to the third direction.

[0018] In some embodiments, the wiring structure may include: a wiring board extending along the upper surface of the longitudinal beam; and a bus bar combined with the wiring board, and the second portion is combined by welding with the bus bar in the third direction.

[0019] In some embodiments, each of the pair of first outer walls may include: an outer wall main body extending in the first direction; and a table surface portion protruding from the outer wall main body toward an adjacent battery cell, and an additional radiator extending in the first direction may also be provided in the table surface portion.

[0020] In some embodiments, the upper surface of the table surface portion may be lower than the upper surface of the outer wall main body and generally flush with the upper surface of the longitudinal beam.

[0021] In some embodiments, the battery pack may further include an additional wiring structure located on the upper surface of the table surface portion.

[0022] In some embodiments, a radiator may not be provided in the bottom below the table surface portion.

[0023] According to a second aspect of the present disclosure, there is provided a method for manufacturing a battery pack, the method for manufacturing the battery pack including: in a vertical coordinate system defined by a first direction, a second direction, and a third direction perpendicular to each other, directly disposing a plurality of battery cells in a battery pack housing, and electrically connecting battery cell leads protruding from at least two adjacent battery cells among the plurality of battery cells in the second direction using a bus bar, wherein electrically connecting the battery cell leads using the bus bar includes connecting each battery cell lead by welding to the bus bar along the third direction. In this case, the battery pack housing 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 inner space of the battery pack housing together with the pair of first outer walls; a longitudinal beam disposed between the pair of first outer walls and extending parallel to the pair of first outer walls; and a bottom disposed below the first outer walls, the second outer walls, and the longitudinal beam, a wiring structure is provided on the longitudinal beam and is electrically connected to the plurality of battery cells, and a radiator is provided in the longitudinal beam.

[0024] In some embodiments, an additional radiator may be provided in the bottom below the plurality of battery cells, and an additional radiator may not be provided in the bottom below the longitudinal beam.

[0025] In some embodiments, each battery cell may include an electrode assembly, a lid surrounding the electrode assembly, and a first battery cell lead protruding from one side of the lid in the second direction. The first battery cell lead may include a first portion relatively close to the lid and a second portion relatively far from the lid. In the first direction, the maximum dimension of the second portion may be larger than the maximum dimension of the first portion, and the second portion may include a plane perpendicular to the third direction. The wiring structure may include: a wiring board extending along the upper surface of the longitudinal beam; and a bus bar coupled to the wiring board.

[0026] In some embodiments, each of the pair of first outer walls may include: an outer wall main body extending in the first direction; and a table surface portion protruding from the outer wall main body toward an adjacent battery cell, and an additional radiator extending in the first direction may also be provided in the table surface portion.

[0027] Advantageous Effects

[0028] In the battery pack of the present disclosure, heat generated inside can be quickly removed to control the rise of the internal temperature and improve safety. Brief Description of the Drawings

[0029] Figure 1is an exploded perspective view of a main part of a battery pack according to an embodiment of the present disclosure.

[0030] Figure 2 is a perspective view of a main part of a lower case of a battery pack housing according to an embodiment of the present disclosure.

[0031] Figure 3 shows Figure 1 a cross-sectional side view taken along line III-III' of a main part of the battery pack shown.

[0032] Figure 4 is a perspective view of a main part of a battery cell according to an embodiment of the present disclosure.

[0033] Figure 5 is a partial enlarged view of a part of a battery cell lead of a battery cell including the battery cell according to an embodiment of the present disclosure.

[0034] Figure 6 is a partial enlarged view of a part of a battery cell lead of a battery cell including the battery cell when viewed in the x-axis direction.

[0035] Figure 7 is a partial enlarged view of a part of a battery cell lead of a battery cell including the battery cell when viewed in the y-axis direction.

[0036] Figure 8 is a partial enlarged view of a part of a battery cell lead of a battery cell including the battery cell when viewed in the z-axis direction.

[0037] Figure 9 is a perspective view of a pair of adjacent battery cells electrically connected to each other by a bus bar.

[0038] Figure 10 is Figure 9 a cross-sectional view of a second part and a bus bar taken along line X-X'.

[0039] Figure 11 is a cross-sectional side view of a main part of a battery pack according to another embodiment of the present disclosure.

[0040] Figure 12 is a flowchart of a manufacturing method of a battery pack according to an embodiment of the present disclosure.

[0041] Figure 13A and Figure 13B is a perspective view showing a manufacturing method of a battery pack according to an embodiment of the present disclosure. Detailed Description

[0042] In the following, embodiments of the concepts of the present disclosure will be described in detail with reference to the accompanying drawings. However, the embodiments of the concepts of the present disclosure can be implemented in many different forms, and thus the scope of the present disclosure should not be construed as being limited by the embodiments described below. It should be understood that the embodiments of the concepts of the present disclosure are provided to more fully describe the concepts of the present disclosure to those of ordinary skill in the art. Throughout the specification, the same reference numerals denote the same elements. In addition, in the drawings, the various elements and regions are schematically shown. Therefore, the concepts of the present disclosure are not limited by the relative sizes of the elements shown in the drawings or the intervals between the elements.

[0043] Terms such as first and second may be used to describe various components, but the components are not limited by the terms. These terms are only used for the purpose of distinguishing one component from another. For example, without departing from the scope of the present disclosure, the first component may be referred to as the second component, and similarly, the second component may be referred to as the first component.

[0044] The terms used in this application are only for describing specific embodiments and are not intended to limit the concepts of the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. It should be understood that when the terms "comprises" and / or "comprising" are used herein, it specifies the presence of the stated features, numbers, steps, operations, elements, components, or combinations thereof, without precluding the presence or addition of one or more other features, numbers, steps, operations, elements, components, or combinations thereof.

[0045] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the technical field to which the concepts of the present disclosure belong. Additionally, terms that are commonly used and defined in a dictionary should be interpreted as having a meaning consistent with the context of the related art, and should not be interpreted in an overly formal sense unless explicitly defined herein.

[0046] When an embodiment can be implemented in a different manner, a part of the operations can be performed in an order different from the order described below. For example, two operations described consecutively can be performed substantially simultaneously or in an order opposite to the order described below.

[0047] It can be expected that, for example, the shapes of the components shown in the drawings may vary according to manufacturing techniques and / or tolerances. Accordingly, embodiments of the present disclosure should not be construed as being limited by the specific shapes of the respective regions shown in this specification, but should be understood to cover, for example, variations in the shapes of the respective regions caused in the manufacturing process. As used herein, the term "and / or" includes any and all combinations of one or more of the related listed items. The term "substrate" as used herein should be understood to represent a substrate or a stacked structure including the substrate and layers, films, etc. formed on the surface of the substrate. In addition, the expression "surface of the substrate" as used herein should be understood to represent the exposed surface of the substrate or the outer surface of a layer or film formed on the substrate.

[0048] Figure 1 is an exploded perspective view of a main part of a battery pack 10 according to an embodiment of the present disclosure. Figure 1 The battery pack 10 is shown defined in a vertical coordinate system, which is defined by a first direction along the x-axis, a second direction along the y-axis, and a third direction along the z-axis that are perpendicular to each other, but the first direction, the second direction, and the third direction are not particularly limited as long as they are perpendicular to each other.

[0049] Referring to Figure 1 , the battery pack 10 includes a plurality of battery cells 100 stacked in a first direction (e.g., the x-axis direction) and a battery pack housing 300 that houses the plurality of battery cells 100 therein.

[0050] The battery pack housing 300 includes an internal space 330 for housing the plurality of battery cells 100. In some embodiments, the battery pack housing 300 may include an upper housing 310 and a lower housing 320 that define the internal space 330.

[0051] Although Figure 1 not explicitly shown in

[0052] a wire may be embedded in the battery pack housing 300 to electrically connect the plurality of battery cells 100 to an external electrical load. In some embodiments, the lower housing 320 may have a box shape with an open upper end, and the plurality of battery cells 100 may be housed in the internal space 330. The upper housing 310 may be in the form of a cover that covers the open upper end of the lower housing 320. In some embodiments, the upper housing 310 may be in the form of a box with an open lower end.

[0053] The battery pack housing 300 may include a plastic material or a metal material. In addition, one of various external materials of battery packs known at the time of filing the present disclosure may be employed as the material of the battery pack housing 300.

[0054] The battery pack 10 may further include a battery management system (BMS). The BMS may be installed in the internal space 330 of the battery pack housing 300 and configured to control all operations of the battery cells 100, such as charge / discharge operations, data transmission / reception operations, etc. The BMS may be provided in the unit of the battery pack rather than in the unit of the battery module. More specifically, the BMS may be configured to control the charge / discharge state, power state, performance state, etc. of the battery cells 100 based on the battery pack voltage and the battery pack current.

[0055] The battery pack 10 may further include a battery disconnect unit (BDU). The BDU may be configured to control the electrical connection between the battery cells to manage the power capacity and functions of the battery pack 10. To this end, the BDU may include: a power relay, a current sensor, a fuse, etc. Similarly, the BDU is a component provided in the unit of the battery pack rather than in the unit of the battery module, and various types of disconnect units known at the time of filing this disclosure may be employed as the BDU.

[0056] The battery pack 10 may further include components of various types of battery packs known at the time of filing this disclosure. For example, according to an embodiment of the present disclosure, the battery pack 10 may further include a manual service disconnect (MSD) to cut off power by manually separating a service plug by a worker.

[0057] Figure 2 is a perspective view of a main part of the lower housing 320 of the battery pack housing 300 according to an embodiment of the present disclosure.

[0058] Referring to Figure 2 , the lower housing 320 includes a pair of first outer walls 321 extending in a first direction (e.g., the x-axis direction). The lower housing 320 further includes a pair of second outer walls 322 extending in a second direction (e.g., the y-axis direction) and defining the internal space 330 of the battery pack housing 300 together with the pair of first outer walls 321. In some embodiments, the first outer walls 321 and the second outer walls 322 may be integrally formed.

[0059] The lower housing 320 further includes a longitudinal beam 323 extending between the pair of first outer walls 321 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 abut against the pair of second outer walls 322. In some embodiments, the longitudinal beam 323 may be integrally formed with the second outer walls 322.

[0060] In some embodiments, the longitudinal beam 323 may have a tabletop 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 side wall of the longitudinal beam 323 may extend downwardly inclined relative to its upper surface. In some embodiments, the side wall of the longitudinal beam 323 may extend perpendicularly to its upper surface. In some embodiments, the side wall of the longitudinal beam 323 may be configured to correspond to the edge shape of the adjacent battery cell 100.

[0061] The longitudinal beam 323 may define an internal space 330 (see Figure 1 ) for accommodating the battery cell 100 together with the adjacent first outer wall 321 in the first outer wall 321.

[0062] In some embodiments, the lower housing 320 may include more than two longitudinal beams 323. In some embodiments, the battery pack housing 300 may include more than two longitudinal beams 323. When the lower housing 320 includes more than two longitudinal beams 323, two adjacent longitudinal beams 323 may define an internal space for accommodating the battery cell 100 (see Figure 1 ).

[0063] Figure 3 is a side cross-sectional view taken along line III-III' showing the main part of the battery pack 10 Figure 1 .

[0064] Referring to Figure 2 and Figure 3 , each of a pair of first outer walls 321 may include an outer wall main body 3211 extending in a first direction (e.g., the x-axis direction) and a tabletop portion 3212 protruding from the outer wall main body 3211 toward the battery cell 100 adjacent to the outer wall main body 3211.

[0065] The tabletop portion 3212 may extend in the first direction (e.g., the x-axis direction) and be in contact with a pair of second outer walls 322. In some embodiments, the tabletop portion 3212 may be integrally formed with the outer wall main body 3211 and / or the second outer wall 322.

[0066] The upper surface of the tabletop portion 3212 may be lower than the upper surface of the second outer wall 322. In some embodiments, the upper surface of the tabletop portion 3212 may be coplanar with the upper surface of the longitudinal beam 323. In some embodiments, the width of the upper surface of the tabletop portion 3212 may be smaller than the width of the upper surface of the longitudinal beam 323.

[0067] In some embodiments, the side wall of the tabletop portion 3212 may extend downwardly inclined relative to its upper surface. In some other embodiments, the side wall of the tabletop portion 3212 may extend perpendicularly to its upper surface. In some embodiments, the side portion of the tabletop portion 3212 may be configured to correspond to the edge shape of the adjacent battery cell 100.

[0068] A wiring structure 350 may be provided on the upper surface of the longitudinal beam 323. The wiring structure 350 may be a structure for electrically connecting the battery cells 100. In some embodiments, the wiring structure 350 may include a wiring board 352 extending along the longitudinal beam 323 in a first direction (e.g., an x-axis direction). The wiring board 352 may include an insulating layer and a wire formed on the insulating layer.

[0069] In some embodiments, the wiring structure 350 may further include bus bars 200 on a wiring board 352 .

[0070] The bus bar 200 may be a conductor that electrically connects two adjacent battery cells 100 in a first direction (eg, an x-axis direction), as described in more detail below.

[0071] A heat sink 3251 penetrating the longitudinal beam 323 in a first direction (e.g., the x-axis direction) may be provided in the longitudinal beam 323. For example, the heat sink 3251 may be a channel for a cooling fluid extending in the first direction (e.g., the x-axis direction). The cooling fluid may be a liquid, a gas, or a mixture thereof. For example, the cooling fluid may be water, air, alcohol, nitrogen, etc., but is not limited thereto.

[0072] like Figure 3 As shown, on the longitudinal beam 323, the battery cell lead 110 of the battery cell 100 is combined with the bus bar 200, and during the operation of the battery pack 10, a large amount of heat is generated at the interface between the battery cell lead 110 and the bus bar 200. Therefore, the heat sink 3251 penetrating the inside of the longitudinal beam 323 can quickly remove the large amount of generated heat, thereby controlling the temperature rise of the battery pack 10 and improving the safety of the battery pack 10.

[0073] The heat sink 3251 may be connected to a cooling fluid reservoir outside the battery pack housing 300 for fluid communication. In some embodiments, the cooling fluid reservoir may be configured to cool a fluid stored therein.

[0074] In some embodiments, an additional wiring structure 350 may be further provided on the upper surface of the mesa portion 3212 of each first outer wall 321. The wiring structure 350 on the mesa portion 3212 may further include a wiring board 352 and a bus bar 200.

[0075] A heat sink 3252 penetrating the table portion 3212 in a first direction (e.g., the x-axis direction) may be provided on the table portion 3212. For example, the heat sink 3252 may be a channel for a cooling fluid extending in the first direction (e.g., the x-axis direction). The cooling fluid may be a liquid, a gas, or a mixture thereof. For example, the cooling fluid may be water, air, alcohol, nitrogen, etc., but is not limited thereto.

[0076] In some embodiments, on the table portion 3212, the cell lead 110 of the battery cell 100 is coupled to the bus bar 200, and during the operation of the battery pack 10, a large amount of heat is generated at the interface between the cell lead 110 and the bus bar 200. Accordingly, the heat sink 3252 penetrating the interior of the table portion 3212 can rapidly remove the large amount of generated heat, thereby controlling the temperature rise of the battery pack 10 and improving the safety of the battery pack 10.

[0077] The heat sink 3252 can be connected to a coolant reservoir outside the battery pack housing 300 for fluid communication. In some embodiments, the coolant reservoir can be configured to cool the fluid stored therein.

[0078] The lower case 320 further includes a bottom 326. The bottom 326 is disposed 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 can be integrally formed with at least one of the pair of first outer walls 321, the pair of second outer walls 322, or the longitudinal beam 323.

[0079] In some embodiments, an additional heat sink 3253 can also be provided in the bottom 326 below the battery cell 100. For example, the additional heat sink 3253 can be a channel for the coolant extending in a first direction (e.g., the x-axis direction). The coolant can be a liquid, a gas, or a mixture thereof. For example, the coolant can be water, air, alcohol, nitrogen, etc., but is not limited thereto.

[0080] Since the additional heat sink 3253 rapidly removes the heat generated during charging and discharging of the battery cell 100, the temperature rise of the battery pack 10 can be controlled and the safety of the battery pack 10 can be improved.

[0081] In some embodiments, a heat sink may not be provided in the bottom 326 below the longitudinal beam 323. In some embodiments, a heat sink may not be provided in the bottom 326 below the table portion 3212.

[0082] Figure 4 is a perspective view of a main part of the battery cell 100 according to an embodiment of the present disclosure.

[0083] Referring to Figure 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 a second direction (e.g., the y-axis direction).

[0084] In some embodiments, the battery cell 100 can be a pouch-type battery cell, but the present disclosure is not limited thereto. In some embodiments, the battery cell 100 can be a prismatic battery cell.

[0085] In some embodiments, the battery cell 100 includes a thin plate-shaped body and preferably may have a structure of a pouch-type battery cell. The pouch-type battery cell may have a structure in which a positive electrode, a separator, and a negative electrode are alternately laminated to form an electrode assembly 101, and electrode tabs are pulled out from at least one side of the electrode assembly 101 and connected to the battery cell lead 110. The positive electrode and the negative electrode can be prepared by coating at least one surface of a current collector with a slurry of, for example, an electrode active material, an adhesive resin, a conductive agent, and other additives. As the electrode active material, in the case of the positive electrode, a conventional positive electrode active material containing a lithium-containing transition metal oxide can be used, and in the case of the negative electrode, a conventional negative electrode active material capable of absorbing and releasing lithium ions, such as lithium metal, a carbon material, a metal compound, or a mixture thereof, can be used. A conventional porous polymer film for a lithium secondary battery can be employed as the separator.

[0086] A conventional electrolyte for a lithium secondary battery can be employed as the electrolyte accommodated in the lid 105 together with the electrode assembly 101. The lid 105 is formed of a sheet and includes a housing portion for accommodating the electrode assembly 101. Preferably, the lid 105 is formed by combining a first housing and a second housing formed by processing a sheet into a specific shape. The sheet of the lid 105 has a multilayer structure in which an outermost resin layer formed of an insulating material such as polyethylene terephthalate (PET) or nylon, a metal layer formed of aluminum to maintain mechanical strength and prevent the penetration of moisture and oxygen, and an inner resin layer formed of a polyolefin-based material having thermo-bonding properties and serving as a sealing material are laminated.

[0087] In the sheet of the lid 105, if necessary, an adhesive resin can be inserted between the inner resin layer and the metal layer and between the outermost resin layer and the metal layer. The adhesive resin layer is formed as a single layer or multiple layers for smooth adhesion between different types of materials, and as the material of the adhesive resin layer, a polyolefin-based resin can generally be used, a polyurethane resin can be used for smooth processing, or a mixture thereof can be used.

[0088] As Figure 4 shown, the battery cell 100 includes two main surfaces S1 and S2 perpendicular to a first direction (e.g., the x-axis direction). That is, the battery cell 100 may include a first main surface S1 and a second main surface S2 extending along the Figure 4 yz plane and parallel to each other.

[0089] Figure 5 is a partial enlarged view of a part of the battery cell lead 110 including the battery cell 100 of the battery cell 100 according to an embodiment of the present disclosure.

[0090] Refer toFigure 5 , the battery 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 part 111 and a second part 112. The first part 111 can be closer to the cover 105 than the second part 112. The second part 112 can be the foremost end of the battery cell lead 110 in the second direction.

[0091] The first part 111 and the second part 112 can be electrically connected to each other. In some embodiments, the first part 111 and the second part 112 can be in direct contact with each other, but the present disclosure is not limited thereto. In some embodiments, the first part 111 and the second part 112 can be integrally formed.

[0092] In some embodiments, the first part 111 can have a flat plate shape, which has a plane substantially perpendicular to the first direction (e.g., the x-axis direction) as the main surface. In some embodiments, the second part 112 can be configured as a plane perpendicular to the third direction (e.g., the z-axis direction). Here, configuring the second part 112 as a plane perpendicular to the third direction should be understood to mean that the upper surface and the lower surface of the second part 112 are perpendicular to the third direction and no through holes are provided. In some embodiments, the upper surface and the lower surface of the second part 112 can be perpendicular to the third direction and no through holes can be provided. In some embodiments, the upper surface and the lower surface of the second part 112 can be perpendicular to the third direction and through holes can be provided.

[0093] Figure 6 is a partial enlarged view of a part of the battery cell lead 110 including the battery cell of the battery cell 100 when viewed in the x-axis direction.

[0094] Refer to Figure 6 , the first part 111 of the battery cell lead 110 includes a first upper surface 111a and a first lower surface 111b. The second part 112 of the battery cell lead 110 includes a second upper surface 112a and a second lower surface 112b. Here, "upper surface" and "lower surface" are relative concepts. Therefore, the surface at a relatively high position and the surface at a relatively low position can be defined as "upper surface" and "lower surface" respectively, or one surface can be defined as "upper surface", and the other surface can be defined as "lower surface".

[0095] An intermediate line CL can be defined for the first part 111. The intermediate line CL is a straight line in the second direction (e.g., the y-axis direction) that divides the first part 111 into two halves in the third direction (e.g., the z-axis direction).

[0096] In the third direction, the intermediate line CL can be located between the second upper surface 112a and the second lower surface 112b of the second part 112.

[0097] In a 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. For example, the second dimension H2 can be from about 0.5% to about 50% of the first dimension H1. In some embodiments, the second dimension H2 can be from about 0.5% to about 50%, from about 1% to about 48%, from about 1.5% to about 45%, from about 2% to about 43%, from about 2.5% to about 40%, from about 3% to about 38%, from about 3.5% to about 35%, from about 4% to about 33%, from about 4.5% to about 30%, from about 5% to about 28%, from about 5.5% to about 25%, from about 6% to about 23%, from about 6.5% to about 20%, from about 7% to about 18%, from about 7.5% to about 15%, from about 8% to about 13%, or from about 8.5% to about 10% of the first dimension H1, or can be within a range between two of these values.

[0098] When the second dimension H2 is too small compared to the first dimension H1, the mechanical strength of the second portion 112 may be insufficient, making it prone to damage. When the second dimension H2 is too large compared to the first dimension H1, the weight of the battery cell 100 may increase unnecessarily.

[0099] Figure 7 is a partial enlarged view of a part of the battery cell lead 110 including the battery cell of the battery cell 100 when viewed in the y-axis direction.

[0100] Referring to Figure 7 FIG. , in a first direction (e.g., the x-axis direction), the first portion 111 of the battery cell lead 110 has a first maximum dimension d1, and the second portion 112 of the battery cell lead 110 has a second maximum dimension d2. The second maximum dimension d2 is larger than the first maximum dimension d1. For example, the second maximum dimension d2 can be from about 2 times to about 20 times the first maximum dimension d1. In some embodiments, the second maximum dimension d2 can be from about 2 times to about 20 times, from about 2.5 times to about 19.5 times, from about 3 times to about 19 times, from about 3.5 times to about 18.5 times, from about 4 times to about 18 times, from about 4.5 times to about 17.5 times, from about 5 times to about 17 times, from about 5.5 times to about 16.5 times, from about 6 times to about 16 times, from about 6.5 times to about 15.5 times, from about 7 times to about 15 times, from about 7.5 times to about 14.5 times, from about 8 times to about 14 times, from about 8.5 times to about 13.5 times, from about 9 times to about 13 times, from about 9.5 times to about 12.5 times, from about 10 times to about 12 times, or from about 10.5 times to about 11.5 times the first maximum dimension d1, or can be within a range between two of these values.

[0101] When the second maximum dimension d2 is too small compared to the first maximum dimension d1, it may not be easy to weld the bus bar, which will be described below, to the second part 112. When the second maximum dimension d2 is too large compared to the first maximum dimension d1, the thickness of the battery cell 100 in the first direction (e.g., the x-axis direction) may increase excessively, resulting in a decrease in energy density.

[0102] In some embodiments, the second maximum dimension d2 of the second part 112 in the first direction (e.g., the x-axis direction) may be larger than the battery cell thickness d3 defined between the first main surface S1 and the second main surface S2 of the battery cell 100. In some embodiments, the second maximum dimension d2 of the second part 112 in the first direction (e.g., the x-axis direction) may be smaller than the battery cell thickness d3 defined between the first main surface S1 and the second main surface S2 of the battery cell 100.

[0103] Figure 8 is a partial enlarged view of a part of the battery cell lead 110 including the battery cell of the battery cell 100 when viewed along the z-axis direction.

[0104] Referring to Figure 8 , the projection of the second part 112 on a plane (e.g., the xy plane) perpendicular to the third direction (e.g., the z-axis direction) may be circular. In some embodiments, the projection of the second part 112 on the xy plane may be elliptical, polygonal (e.g., quadrilateral, pentagonal or hexagonal) or any other shape, as well as circular. However, considering the diversity of the welding methods subsequently used to weld the second part 112 to the bus bar, structural stability, ease of operation, etc., the projection of the second part 112 on the xy plane may preferably be circular.

[0105] In some embodiments, when the projection is circular, the second part 112 may be cylindrical or conical. When the projection is polygonal, the second part 112 may be prismatic or pyramidal.

[0106] The projected area of the second part 112 may be about 2 times to about 20 times the projected area of the first part 111. In some embodiments, the projected area of the second part 112 may be about 2 times to about 20 times, about 2.5 times to about 19 times, about 3 times to about 18 times, about 3.5 times to about 17 times, about 4 times to about 16 times, about 4.5 times to about 15 times, about 5 times to about 14 times, about 5.5 times to about 13 times, about 6 times to about 12 times, about 6.5 times to about 11 times, about 7 times to about 10 times or about 7.5 times to about 9 times the projected area of the first part 111, or may be within the range between two of these values.

[0107] When the projected area of the second part 112 is too small compared to the projected area of the first part 111, it may not be easy to weld the second part 112 to the bus bar described below. When the projected area of the second part 112 is too large compared to the projected area of the first part 111, the weight of the battery cell 100 may be unnecessarily increased.

[0108] The second parts 112 of the cell leads 110 of the battery cell 100 each have a planar shape perpendicular to the third direction (e.g., the z-axis direction). Thus, after the battery cells 100 are combined with the battery pack housing 300, the battery cells 100 can be electrically connected to each other. Accordingly, the battery pack according to an embodiment of the present disclosure can be manufactured at low cost, have high productivity, and be less prone to failure due to the small number of components.

[0109] Figure 9 is a perspective view of a pair of adjacent battery cells 100_1 and 100_2 electrically connected to each other by a bus bar 200.

[0110] Referring to Figure 9 , the cell lead 110_1 of the first battery cell 100_1 includes a first part 111_1 and a second part 112_1, and the cell lead 110_2 of the second battery cell 100_2 includes a first part 111_2 and a second part 112_2.

[0111] 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 can be electrically connected to each other by the bus bar 200. Specifically, the second part 112_1 of the first battery cell 100_1 and the second part 112_2 of the second battery cell 100_2 can be electrically connected to each other by the bus bar 200.

[0112] 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 electrically connected to each other by the bus bar 200 can have the same polarity or different polarities.

[0113] The bus bar 200 can be arranged to extend in the first direction (e.g., the x-axis direction) and configured to contact the lower surface of the second part 112_1 of the first battery cell 100_1 and the lower surface of the second part 112_2 of the second battery cell 100_2. In some embodiments, the bus bar 200 can be in the form of a strip extending in the first direction. In this case, the flat surface of the bus bar 200 can face the second part 112_1 of the first battery cell 100_1 and the second part 112_2 of the second battery cell 100_2 in the third direction (e.g., the z-axis direction).

[0114] As referred to aboveFigure 2 and Figure 3 As described above, the bus bar 200 may be disposed on the wiring board 352 provided on the longitudinal beam 323. In some embodiments, the bus bar 200 may be disposed on the wiring board 352 provided on the table portion 3212, as described above with reference to Figure 2 and Figure 3 above.

[0115] The cell lead 110_1 of the first cell 100_1 and the cell lead 110_2 of the second cell 100_2 may extend to the upper part of the longitudinal beam 323. Specifically, the cell lead 110_1 of the first cell 100_1 and the cell lead 110_2 of the second cell 100_2 may be electrically connected to the bus bar 200 on the longitudinal beam 323.

[0116] Figure 10 is Figure 9 A cross-sectional view of the second portions 112_1 and 112_2 taken along line X-X' of and the bus bar 200.

[0117] Referring to Figure 10 , the portion of the bus bar 200 overlapping with the second portions 112_1 and 112_2 may have a recess R recessed in the third direction (e.g., the z-axis direction). In some embodiments, the recess R may be formed as a result of welding the bus bar 200 to the second portions 112_1 and 112_2 in the third direction. However, the recess R is formed as a result of melting and solidifying of the interface between the bus bar 200 and the second portions 112_1 and 112_2 by welding, and thus may appear as traces of melting and solidifying in some cases.

[0118] Figure 10 It is shown that the recess R is continuously formed in the flat surface of the bus bar 200, but in some cases, a slightly raised portion may be formed around the recess R.

[0119] In some embodiments, depending on the welding method, the recess R may not be recognized as a clear interface.

[0120] Figure 11 is a cross-sectional side view of a main part of a battery pack according to another embodiment of the present disclosure.

[0121] Referring to Figure 11 , in some embodiments, an additional radiator may be provided in the bottom 326 below the longitudinal beam 323. In some embodiments, an additional radiator may be provided in the bottom 326 below the table portion 3212. By providing the additional radiator(s) as described above, the heat generated at the point where the cell lead is combined with the bus bar 200 can be removed more quickly.

[0122] Figure 12 is a flowchart of a method for manufacturing the battery pack 10 according to an embodiment of the present disclosure. Figure 13A and Figure 13B is a perspective view showing a method for manufacturing the battery pack 10 according to an embodiment of the present disclosure.

[0123] Referring to Figure 12 and Figure 13A , a plurality of battery cells 100 may be directly disposed in the battery pack housing 300 (S10). Here, the direct disposition of the plurality of battery cells 100 in the battery pack housing 300 should be understood as disposing the plurality of battery cells 100 in the battery pack housing 300 without modularizing the plurality of battery cells 100.

[0124] In some embodiments, the plurality of battery cells 100 may be individually disposed in the battery pack housing 300 one by one. In some embodiments, two or more of the plurality of battery cells 100 may be stacked and then disposed in the battery pack housing 300.

[0125] The method of disposing the battery cell 100 in the battery pack housing 300 is not particularly limited, and the battery cell 100 may be disposed in the battery pack housing 300 by any known method. The configuration of the lower housing 320 has been described above with reference to Figure 2 and Figure 3 , and thus a detailed description thereof is omitted here. The configuration of each battery cell 100 has been described in detail above with reference to Figures 4 to 10 and thus a detailed description thereof is omitted here.

[0126] Referring to Figure 12 and Figure 13B , the battery cell leads 110_1 and 110_2 protruding from two adjacent battery cells 100 in the second direction (e.g., the y-axis direction) may be electrically connected to the bus bar 200 (S20). The battery cell leads 110_1 and 110_2 may be connected by welding to the bus bar 200 along the third direction (e.g., the z-axis direction).

[0127] In some embodiments, the bus bar 200 may be disposed in the battery pack housing 300 before the plurality of battery cells 100 are disposed in the battery pack housing 300. In some embodiments, after the plurality of battery cells 100 are disposed in the battery pack housing 300, the bus bar 200 may be disposed on the battery cell leads 110_1 and 110_2. Thereafter, the bus bar 200 may be welded to the battery cell leads 110_1 and 110_2. The welding method may be any known method and is not particularly limited.

[0128] The second portions 112 of the cell leads 110 of the cell 100 each have a planar shape perpendicular to the third direction (e.g., the z-axis direction), so that after the cells 100 are combined with the battery pack housing 300, the cells 100 can be electrically connected to each other. Accordingly, the battery pack according to an embodiment of the present disclosure can be manufactured at low cost, has high productivity, and is less likely to malfunction due to a small number of components.

[0129] Although the embodiments of the present disclosure have been described in detail above, those of ordinary skill in the art to which the present disclosure pertains can implement the present disclosure in many different forms without departing from the spirit and scope of the present disclosure defined in the appended claims. Accordingly, it should be understood that all modifications in the embodiments of the present disclosure fall within the scope of the present disclosure.

Claims

1. A battery pack, comprising: A plurality of battery cells, in a vertical coordinate system defined by a first direction, a second direction, and a third direction perpendicular to each other, the plurality of battery cells being stacked in the first direction; And A battery pack housing configured to accommodate the plurality of battery cells in an internal space, Wherein, the battery pack housing 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 battery pack housing together with the pair of first outer walls; A longitudinal beam disposed between the pair of first outer walls and extending parallel to the pair of first outer walls; and A bottom disposed below the first outer walls, the second outer walls, and the longitudinal beam, A wiring structure is disposed on the longitudinal beam, and the wiring structure is electrically connected to the plurality of battery cells, and A radiator is disposed in the longitudinal beam.

2. The battery pack according to claim 1, wherein The radiator includes channels for a cooling fluid extending in the first direction.

3. The battery pack according to claim 2, wherein, An additional radiator is also disposed in the bottom below the plurality of battery cells.

4. The battery pack according to claim 3, wherein, No radiator is disposed in the bottom below the longitudinal beam.

5. The battery pack according to claim 1, wherein Each of the battery cells includes an electrode assembly, a cover surrounding the electrode assembly, and a first battery cell lead protruding from one side of the cover to the upper part of the longitudinal beam in the second direction.

6. The battery pack according to claim 5, wherein The first battery cell lead includes a first portion relatively close to the cover and a second portion relatively far from the cover, and In the first direction, the maximum dimension of the second portion is larger than the maximum dimension of the first portion, and the second portion includes a plane perpendicular to the third direction.

7. The battery pack according to claim 5, wherein, The wiring structure includes: A wiring board extending along the upper surface of the longitudinal beam; and A bus bar combined with the wiring board, and Combined by welding the second portion to the bus bar along the third direction.

8. The battery pack according to claim 1, wherein Each of the pair of first outer walls includes: An outer wall main body extending in the first direction; and A table surface portion protruding from the outer wall main body toward an adjacent battery cell, and An additional radiator extending in the first direction is also disposed in the table surface portion.

9. The battery pack according to claim 8, wherein, The upper surface of the table surface portion is lower than the upper surface of the outer wall main body and is generally flush with the upper surface of the longitudinal beam.

10. The battery pack according to claim 8, further comprising an additional wiring structure located on the upper surface of the table surface portion.

11. The battery pack according to claim 8, wherein, No radiator is disposed in the bottom below the table surface portion.

12. A method for manufacturing a battery pack, comprising: In a vertical coordinate system defined by a first direction, a second direction, and a third direction perpendicular to each other, directly disposing a plurality of battery cells in a battery pack housing, and Electrically connecting battery cell leads protruding from at least two adjacent battery cells among the plurality of battery cells in the second direction using a bus bar, Wherein, electrically connecting the battery cell leads using the bus bar includes connecting each of the battery cell leads by welding to the bus bar along the third direction, The battery pack housing includes: a pair of first outer walls that extend in the first direction; a pair of second outer walls that extend in the second direction and, together with the pair of first outer walls, define an internal space of the battery pack housing; a longitudinal beam that is disposed between the pair of first outer walls and extends parallel to the pair of first outer walls; and a bottom that is disposed below the first outer walls, the second outer walls, and the longitudinal beam, a wiring structure is provided on the longitudinal beam, and the wiring structure is electrically connected to the plurality of battery cells, and a radiator is provided in the longitudinal beam.

13. The manufacturing method according to claim 12, wherein, An additional radiator is provided in the bottom below the plurality of battery cells, and the additional radiator is not provided in the bottom below the longitudinal beam.

14. The manufacturing method according to claim 12, wherein, The first battery cell lead includes a first portion relatively close to the lid and a second portion relatively far from the lid, in the first direction, the maximum dimension of the second portion is larger than the maximum dimension of the first portion, and the second portion includes a plane perpendicular to the third direction, and The wiring structure includes: a wiring board that extends along the upper surface of the longitudinal beam; and a bus bar that is coupled to the wiring board.

15. The manufacturing method according to claim 14, wherein, Each of the pair of first outer walls includes: an outer wall main body that extends in the first direction; and a table surface portion that protrudes from the outer wall main body toward an adjacent battery cell, and an additional radiator that extends in the first direction is further provided in the table surface portion.

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