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 the plurality of battery cells in an internal space, in which the pack case includes an upper case and a lower case, the lower case including the internal space accommodating the plurality of battery cells, and the upper case including a heat sink extending in a first direction.

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 rapidly 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. 10-2022-0167143, filed on December 2, 2022, and Korean Patent Application No. 10-2023-0039701, filed on March 27, 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 rapidly increasing. 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 with 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 a lithium secondary battery, a lithium-based oxide and a carbon material 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, i.e., 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, a conventional battery pack is formed by accommodating a plurality of battery cells (secondary batteries) in a module case to form respective battery modules and accommodating at least one such battery module in a battery pack case.

[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 the pouch-type batteries are stacked, but is vulnerable to external impacts and has low assemblability. 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 case. As a representative example, a conventional battery pack is formed by accommodating a plurality of pouch-type battery cells in a module case to form a battery module and accommodating at least one such battery module in a battery pack case.

[0007] However, such a conventional battery pack may be disadvantageous in terms of energy density. Generally, when modularizing a plurality of battery cells by accommodating the plurality of battery cells in a module case, due to various components such as the module case or a battery stack frame, the volume of the battery pack may be unnecessarily increased or the space occupied by the battery cells may be reduced. 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 case 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 case, so the manufacturing process of the battery pack becomes complicated. Moreover, as disclosed in the above 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, including: 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 an upper housing and a lower housing, the lower housing includes an internal space for accommodating the plurality of battery cells, and the upper housing includes a radiator extending in the first direction.

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

[0015] In some embodiments, the lower housing may include: 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, and the lower housing may further include a radiator disposed on the bottom and extending in the first direction.

[0016] In some embodiments, the plurality of battery cells may be coupled to the upper housing by a first adhesive resin.

[0017] In some embodiments, the radiator of the upper housing may be disposed to overlap with the first adhesive resin.

[0018] In some embodiments, the plurality of battery cells may be coupled to the upper housing by a second adhesive resin, and the radiator in the bottom of the lower housing may be disposed to overlap with the second adhesive resin.

[0019] In some embodiments, a wiring structure may be disposed on the longitudinal beam and electrically connected to the plurality of battery cells, and an additional radiator may be disposed in the longitudinal beam.

[0020] In some embodiments, no radiator may be disposed in the bottom below the longitudinal beam.

[0021] 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 stepped 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 disposed in the stepped surface portion.

[0022] In some embodiments, the upper surface of the stepped surface portion may be lower than the upper surface of the outer wall main body and substantially flush with the upper surface of the longitudinal beam.

[0023] A second aspect of the present disclosure provides a method for manufacturing a battery pack, the manufacturing method 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 lower housing of the battery pack housing; using a bus bar to electrically connect battery cell leads protruding from at least two adjacent battery cells among the plurality of battery cells in the second direction; disposing a first adhesive resin on the plurality of battery cells combined with the bus bar; combining an upper housing to the lower housing provided with the plurality of battery cells; and curing the first adhesive resin, wherein using the bus bar to electrically connect the battery cell leads includes connecting each battery cell lead by welding to the bus bar along the third direction, and the upper housing includes a heat sink extending in the first direction.

[0024] In some embodiments, the heat sink may be disposed to overlap with the first adhesive resin.

[0025] In some embodiments, directly disposing the plurality of battery cells in the lower housing of the battery pack housing may include: coating a second adhesive resin on positions of the bottom of the lower housing corresponding to the plurality of battery cells; and directly disposing the plurality of battery cells in the lower housing in contact with the second adhesive resin.

[0026] In some embodiments, the lower housing may include: 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 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 may be disposed on the longitudinal beam and electrically connected to the plurality of battery cells, and an additional heat sink may be disposed in the longitudinal beam.

[0027] 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 heat sink extending in the first direction may also be disposed in the table surface portion.

[0028] Advantageous Effects

[0029] In the battery pack of the present disclosure, heat generated inside can be quickly removed to easily control the rise of the internal temperature and improve safety. Brief Description of the Drawings

[0030] Figure 1 is an exploded perspective view of a main part of a battery pack according to an embodiment of the present disclosure.

[0031] Figure 2Is a perspective view of a main part of a lower housing of a battery pack housing according to an embodiment of the present disclosure.

[0032] Figure 3 Is a cross-sectional side view taken along line III-III’ showing a main part of a battery pack. Figure 1

[0033] Figure 4 Is a perspective view of a main part of a battery cell according to an embodiment of the present disclosure.

[0034] Figure 5 Is a partial enlarged view of a part of a battery cell lead of a battery cell according to an embodiment of the present disclosure.

[0035] Figure 6 Is a partial enlarged view of a part of a battery cell lead of a battery cell when viewed in the x-axis direction.

[0036] Figure 7 Is a partial enlarged view of a part of a battery cell lead of a battery cell when viewed in the y-axis direction.

[0037] Figure 8 Is a partial enlarged view of a part of a battery cell lead of a battery cell when viewed in the z-axis direction.

[0038] Figure 9 Is a perspective view of a pair of adjacent battery cells electrically connected to each other through a bus bar.

[0039] Figure 10 Is a Figure 9 Cross-sectional view of a second part taken along line X-X’ and the bus bar.

[0040] Figure 11 Is a flowchart of a manufacturing method of a battery pack according to an embodiment of the present disclosure.

[0041] Figures 12A to 12D Is a perspective view showing a manufacturing method of a battery pack according to an embodiment of the present disclosure. Detailed Description

[0042] ​Hereinafter, 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, so 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 illustrated. 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 these 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, singular expressions are also intended to include 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 (including technical and scientific terms) used herein 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 relevant art and should not be interpreted in an overly formal sense unless expressly defined herein.

[0046] When embodiments can be implemented in different ways, some 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. Therefore, the 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 a substrate and layers, films, etc. formed on the surface of the substrate. Additionally, 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 the main part of the 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. However, 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 is not explicitly shown in

[0052] , wires may be embedded in the battery pack housing 300 to electrically connect the plurality of battery cells 100 to an external electrical load.

[0053] 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.

[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 and 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 and discharge states, power states, performance states, etc. of the battery cells 100 based on the battery pack voltage and 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 the service plug by a worker.

[0057] Figure 2 is a perspective view of a main portion of the lower housing 320 of the battery pack housing 300 according to an embodiment of the present disclosure. Figure 3 is shown Figure 1 a side cross-sectional view taken along line III-III' of the main portion of the battery pack 10.

[0058] Referring to Figures 1 to 3 , the upper housing 310 is configured to define the internal space 330 together with the lower housing 320.

[0059] The upper housing 310 may include a radiator 315 extending in a first direction (e.g., the x-axis direction). For example, the radiator 315 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.

[0060] The battery cell 100 may be coupled to the upper housing 310 by a first adhesive resin 318. As the first adhesive resin 318, a material having thermal conductivity and adhesive properties may be used. In some embodiments, the first adhesive resin 318 may include an acrylic resin, a polyurethane resin, a silicone resin, or a mixture thereof.

[0061] The thickness of the first adhesive resin 318 may be from about 0.8 mm to about 1.2 mm. When the thickness of the first adhesive resin 318 is too small, it is difficult to expect sufficient heat dissipation effect and fixing force. When the thickness of the first adhesive resin 318 is too large, the effect saturates compared to the cost increase, resulting in economic drawbacks.

[0062] In some embodiments, the heat sink 315 may be arranged to overlap with the first adhesive resin 318 in the third direction (e.g., the z-axis direction). Since the heat sink 315 overlaps with the first adhesive resin 318, the heat generated in the battery cell 100 can be quickly dissipated to the outside.

[0063] Referring to Figures 1 to 3 , the lower case 320 includes a pair of first outer walls 321 extending in the first direction (e.g., the x-axis direction). The lower case 320 further includes a pair of second outer walls 322 extending in the second direction (e.g., the y-axis direction) and defining an 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.

[0064] The lower case 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 connect to the pair of second outer walls 322. In some embodiments, the longitudinal beam 323 may be integrally formed with the second outer walls 322.

[0065] 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 walls 322. In some embodiments, the side walls of the longitudinal beam 323 may extend downwardly inclined with respect to its upper surface. In some embodiments, the side walls of the longitudinal beam 323 may extend perpendicularly to its upper surface. In some embodiments, the side walls of the longitudinal beam 323 may be configured to correspond to the edge shape of the adjacent battery cell 100.

[0066] The longitudinal beam 323 may, together with adjacent first outer walls 321 among the first outer walls 321, define an internal space 330 for accommodating the battery cell 100 (see Figure 1 ).

[0067] In some embodiments, the lower case 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 case 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 ).

[0068] 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 table surface portion 3212 protruding from the outer wall main body 3211 toward a battery cell 100 adjacent to the outer wall main body 3211.

[0069] The table surface portion 3212 may extend in the first direction (e.g., the x-axis direction) and be joined to a pair of second outer walls 322. In some embodiments, the table surface portion 3212 may be integrally formed with the outer wall main body 3211 and / or the second outer walls 322.

[0070] The upper surface of the table surface portion 3212 may be lower than the upper surface of the second outer walls 322. In some embodiments, the upper surface of the table surface 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 table surface portion 3212 may be smaller than the width of the upper surface of the longitudinal beam 323.

[0071] In some embodiments, the side walls of the table surface portion 3212 may extend downwardly inclined with respect to its upper surface. In some other embodiments, the side walls of the table surface portion 3212 may extend perpendicular to its upper surface. In some embodiments, the side portions of the table surface portion 3212 may be configured to correspond to the edge shape of the battery cell 100 adjacent thereto.

[0072] 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 the first direction (e.g., the x-axis direction). The wiring board 352 may include an insulating layer and a conductive wire formed on the insulating layer.

[0073] In some embodiments, the wiring structure 350 may further include a bus bar 200 on the wiring board 352.

[0074] The bus bar 200 may be a conductor that electrically connects two adjacent battery cells 100 in the first direction (e.g., the x-axis direction), as described in more detail below.

[0075] A radiator 3251 may be provided in the longitudinal beam 323 and penetrate the longitudinal beam 323 in the first direction (e.g., the x-axis direction). For example, the radiator 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.

[0076] As Figure 3As shown, on the longitudinal beam 323, the 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 cell lead 110 and the bus bar 200. Therefore, the heat sink 3251 penetrating the interior 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.

[0077] The heat sink 3251 can be connected to a cooling fluid reservoir outside the battery pack housing 300 for fluid communication. In some embodiments, the cooling fluid reservoir can be configured to cool the fluid stored therein.

[0078] In some embodiments, an additional wiring structure 350 can also be provided on the upper surface of the stepped portion 3212 of each first outer wall 321. The wiring structure 350 on the stepped portion 3212 can also include a wiring board 352 and the bus bar 200.

[0079] A heat sink 3252 penetrating the stepped portion 3212 in the first direction (e.g., the x-axis direction) can be provided on the stepped portion 3212. For example, the heat sink 3252 can be a channel for cooling fluid extending in the first direction (e.g., the x-axis direction). The cooling fluid can be a liquid, a gas, or a mixture thereof. For example, the cooling fluid can be water, air, alcohol, nitrogen, etc., but is not limited thereto.

[0080] In some embodiments, on the stepped portion 3212, the 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 cell lead 110 and the bus bar 200. Therefore, the heat sink 3252 penetrating the interior of the stepped portion 3212 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.

[0081] The heat sink 3252 can be connected to a cooling fluid reservoir outside the battery pack housing 300 for fluid communication. In some embodiments, the cooling fluid reservoir can be configured to cool the fluid stored therein.

[0082] The lower housing 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.

[0083] In some embodiments, an additional radiator 3253 may be provided in the bottom 326 below the battery cell 100. For example, the additional radiator 3253 may be a channel for a cooling fluid that extends in a 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.

[0084] Since the additional radiator 3253 quickly 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.

[0085] In some embodiments, a radiator may not be provided in the bottom 326 below the longitudinal beam 323. In some embodiments, a radiator may not be provided in the bottom 326 below the table surface portion 3212.

[0086] The battery cell 100 may be coupled to the lower case 320 by a second adhesive resin 328. As the second adhesive resin 328, a material having thermal conductivity and adhesive properties may be used. In some embodiments, the second adhesive resin 328 may include an acrylic resin, a polyurethane resin, a silicone resin, or a mixture thereof.

[0087] The thickness of the second adhesive resin 328 may be about 0.8 mm to about 1.2 mm. When the thickness of the second adhesive resin 328 is too small, it is difficult to expect sufficient heat dissipation effect and fixing force. When the thickness of the second adhesive resin 328 is too large, the effect is saturated compared to the cost increase, resulting in economic disadvantages.

[0088] In some embodiments, the radiator 3253 may be disposed to overlap the second adhesive resin 328 in a third direction (e.g., the z-axis direction). Since the radiator 3253 overlaps the second adhesive resin 328, the heat generated in the battery cell 100 can be quickly dissipated to the outside.

[0089] Figure 4 is a perspective view of a main part of a battery cell 100 according to an embodiment of the present disclosure.

[0090] Refer to Figure 4 , the battery cell 100 includes an electrode assembly 101, a cover 105 surrounding the electrode assembly 101, and a battery cell lead 110 protruding from one side of the cover 105 in a second direction (e.g., the y-axis direction).

[0091] In some embodiments, the battery cell 100 may be a pouch-type battery cell, but the present disclosure is not limited thereto. In some embodiments, the battery cell 100 may be a prismatic battery cell.

[0092] In some embodiments, the battery cell 100 includes a thin plate-shaped body and preferably may have the 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.

[0093] A conventional electrolyte for a lithium secondary battery can be adopted 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 receiving 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 the 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.

[0094] 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.

[0095] As Figure 4 shown, the battery cell 100 includes two main surfaces S1 and S2 perpendicular to the 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 2 yz plane and parallel to each other.

[0096] 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.

[0097] Referring to Figure 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 portion 111 and a second portion 112. The first portion 111 may be closer to the cover 105 than the second portion 112. The second portion 112 may be the foremost end portion of the battery cell lead 110 in the second direction.

[0098] 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 disclosure is not limited thereto. In some embodiments, the first portion 111 and the second portion 112 may be integrally formed.

[0099] In some embodiments, the first portion 111 may have a flat plate shape with a plane substantially perpendicular to the first direction (e.g., the x-axis direction) as the main surface. 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, configuring the second portion 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 portion 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 portion 112 may be perpendicular to the third direction and no through holes may be provided. In some embodiments, the upper surface and the lower surface of the second portion 112 may be perpendicular to the third direction and through holes may be provided.

[0100] 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.

[0101] Referring to Figure 6 , the first portion 111 of the battery cell lead 110 includes a first upper surface 111a and a first lower surface 111b. The second portion 112 of the battery cell lead 110 includes a second upper surface 112a and a second lower surface 112b. Here, the "upper surface" and the "lower surface" are relative concepts. Therefore, the surface at a relatively high position and the surface at a relatively low position may be defined as the "upper surface" and the "lower surface" respectively, or one surface may be defined as the "upper surface" and the other surface may be defined as the "lower surface".

[0102] An intermediate line CL may be defined for the first portion 111. The intermediate line CL is a straight line in the second direction (e.g., the y-axis direction) that divides the first portion 111 into two halves in the third direction (e.g., the z-axis direction).

[0103] In the third direction, the intermediate line CL may be located between the second upper surface 112a and the second lower surface 112b of the second portion 112.

[0104] 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%, about 1% to about 48%, about 1.5% to about 45%, about 2% to about 43%, about 2.5% to about 40%, about 3% to about 38%, about 3.5% to about 35%, about 4% to about 33%, about 4.5% to about 30%, about 5% to about 28%, about 5.5% to about 25%, about 6% to about 23%, about 6.5% to about 20%, about 7% to about 18%, about 7.5% to about 15%, about 8% to about 13%, or about 8.5% to about 10% of the first dimension H1, or can be within a range between two of these values.

[0105] 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.

[0106] 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.

[0107] Referring to Figure 7 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, about 2.5 times to about 19.5 times, about 3 times to about 19 times, about 3.5 times to about 18.5 times, about 4 times to about 18 times, about 4.5 times to about 17.5 times, about 5 times to about 17 times, about 5.5 times to about 16.5 times, about 6 times to about 16 times, about 6.5 times to about 15.5 times, about 7 times to about 15 times, about 7.5 times to about 14.5 times, about 8 times to about 14 times, about 8.5 times to about 13.5 times, about 9 times to about 13 times, about 9.5 times to about 12.5 times, about 10 times to about 12 times, or 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.

[0108] 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 portion 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.

[0109] In some embodiments, the second maximum dimension d2 of the second portion 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 portion 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.

[0110] 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.

[0111] Referring to Figure 8 , the projection of the second portion 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 portion 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 portion 112 to the bus bar, structural stability, ease of operation, etc., the projection of the second portion 112 on the xy plane may preferably be circular.

[0112] In some embodiments, when the projection is circular, the second portion 112 may be cylindrical or conical. When the projection is polygonal, the second portion 112 may be prismatic or pyramidal.

[0113] The projected area of the second portion 112 may be about 2 times 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 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 portion 111, or may be within the range between two of these values.

[0114] When 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 the second portion 112 to the bus bar described below. When 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 be unnecessarily increased.

[0115] The second portions 112 of the cell leads 110 of the battery cells 100 each have a planar shape perpendicular to the third direction (e.g., the z-axis direction). Thus, after the battery cells 100 are coupled to 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.

[0116] 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.

[0117] Referring to Figure 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.

[0118] 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 portion 112_1 of the first battery cell 100_1 and the second portion 112_2 of the second battery cell 100_2 can be electrically connected to each other by the bus bar 200.

[0119] 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.

[0120] 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 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 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 portion 112_1 of the first battery cell 100_1 and the second portion 112_2 of the second battery cell 100_2 in the third direction (e.g., the z-axis direction).

[0121] 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 surface portion 3212, as described above with reference to Figure 2 and Figure 3 above.

[0122] 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 portion 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.

[0123] 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.

[0124] 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 generated 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 generated as a result of melting and solidifying at the interface between the bus bar 200 and the second portions 112_1 and 112_2, and thus may appear as traces of melting and solidifying in some cases.

[0125] 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.

[0126] In some embodiments, depending on the welding method, the recess R may not be recognized as a clear interface.

[0127] In the battery pack 10 according to the embodiment of the present disclosure described above, the heat generated inside can be quickly removed to easily control the rise of the internal temperature and improve safety.

[0128] Figure 11 is a flowchart of a method for manufacturing the battery pack 10 according to an embodiment of the present disclosure. Figures 12A to 12D is a perspective view showing a method for manufacturing the battery pack 10 according to an embodiment of the present disclosure.

[0129] Referring to Figure 11 and Figure 12A, a plurality of battery cells 100 can 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.

[0130] In some embodiments, the plurality of battery cells 100 can 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 can be stacked and then disposed in the battery pack housing 300.

[0131] Before disposing the plurality of battery cells 100 in the battery pack housing 300, a layer of a second adhesive resin 328 can be formed on the bottom of the lower housing 320 of the battery pack housing 300. The second adhesive resin 328 can include: an acrylic resin, a polyurethane resin, a silicone resin, or a mixture thereof. The layer thickness of the second adhesive resin 328 can be about 0.8 mm to about 1.2 mm. In some embodiments, the amount and position of the second adhesive resin 328 to be supplied can be controlled such that after curing the second adhesive resin 328, the thickness of the second adhesive resin 328 is within the range of about 0.8 mm to about 1.2 mm. The layer of the second adhesive resin 328 can be formed at the position where the plurality of battery cells 100 are disposed.

[0132] Thereafter, the battery cell 100 can be directly disposed in the lower housing 320 such that the edge of the battery cell 100 facing the bottom of the lower housing 320 contacts the layer of the second adhesive resin 328.

[0133] The method of disposing the battery cell 100 in the battery pack housing 300 is not particularly limited, and the battery cell 100 can be disposed in the battery pack housing 300 by any known method. The above has been referred to Figures 1 to 3 The configuration of the lower housing 320 has been described, and thus its detailed description is omitted here. The above has been referred to Figures 4 to 10 The configurations of the respective battery cells 100 have been described in detail, and thus their detailed descriptions are omitted here.

[0134] Referring to Figure 11 and FIG. 12, 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) can be electrically connected to the bus bar 200 (S20). The battery cell leads 110_1 and 110_2 can be connected by welding to the bus bar 200 along the third direction (e.g., the z-axis direction).

[0135] 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.

[0136] The second portions 112 of the battery cell leads 110 of the battery cells 100 each have a planar shape perpendicular to the third direction (e.g., the z-axis direction), so that after the battery cells 100 are combined with the battery pack housing 300, the battery cells 100 can be electrically connected to each other. Therefore, 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 fail due to the small number of components.

[0137] Referring to Figure 11 and Figure 12C , in the lower housing 320, the first adhesive resin 318 is disposed on the plurality of battery cells 100 combined with the bus bar 200 (S30). The first adhesive resin 318 may be disposed on the upper edges of the battery cells 100 stacked in the first direction (e.g., the x-axis direction). The first adhesive resin 318 does not necessarily have to be disposed as a thin film, and may be disposed at an appropriate position, and when the upper housing 310 and the lower housing 320 are combined, the amount of the first adhesive resin 318 is sufficient for the first adhesive resin 318 to be distributed with an appropriate thickness and width. The first adhesive resin 318 may include an acrylic resin, a polyurethane resin, a silicone resin, or a mixture thereof.

[0138] Referring to Figure 11 and Figure 12D , the upper housing 310 may be combined with the lower housing 320 that houses the plurality of battery cells 100 (S40).

[0139] Specifically, by pressing the first adhesive resin 318 by the upper housing 310 to spread with an appropriate width on the upper edges of the battery cells 100, the battery pack housing 300 can be sealed by bringing the upper housing 310 and the lower housing 320 into close contact with each other.

[0140] Thereafter, the first adhesive resin 318 may be cured (S50).

[0141] In the battery pack 10 manufactured by the above manufacturing method according to an embodiment of the present disclosure, the heat generated inside can be quickly removed to easily control the rise of the internal temperature and improve safety.

[0142] 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 as defined in the appended claims. Therefore, it should be understood that all modifications of 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 an upper housing and a lower housing, The lower housing includes an internal space for accommodating the plurality of battery cells, and The upper housing includes a radiator extending in the first direction.

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

3. The battery pack according to claim 1, wherein, The lower 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, and The lower housing further includes a radiator disposed in the bottom and extending in the first direction.

4. The battery pack according to claim 3, wherein, The plurality of battery cells are bonded to the upper housing by a first adhesive resin.

5. The battery pack according to claim 4, wherein, The radiator of the upper housing is disposed to overlap with the first adhesive resin.

6. The battery pack according to claim 4, wherein, The plurality of battery cells are bonded to the upper housing by a second adhesive resin, and the radiator in the bottom of the lower housing is disposed to overlap with the second adhesive resin.

7. The battery pack according to claim 3, wherein A wiring structure is disposed on the longitudinal beam, and the wiring structure is electrically connected to the plurality of battery cells, and An additional radiator is disposed in the longitudinal beam.

8. The battery pack according to claim 7, wherein, No radiator is disposed in the bottom below the longitudinal beam.

9. The battery pack according to claim 3, 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 further disposed in the table surface portion.

10. The battery pack according to claim 9, 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.

11. 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 lower housing of a battery pack housing; Using a bus bar to electrically connect battery cell leads protruding from at least two adjacent battery cells among the plurality of battery cells in the second direction; Disposing a first adhesive resin on the plurality of battery cells combined with the bus bar; Combining an upper housing to the lower housing provided with the plurality of battery cells; And Curing the first adhesive resin, Wherein, using the bus bar to electrically connect the battery cell leads includes connecting each of the battery cell leads by welding to the bus bar along the third direction, and The upper housing includes a radiator extending in the first direction.

12. The manufacturing method according to claim 11, wherein, The radiator is disposed to overlap with the first adhesive resin.

13. The manufacturing method according to claim 11, wherein Directly disposing the plurality of battery cells in the lower housing of the battery pack housing includes: Coating a second adhesive resin at positions corresponding to the plurality of battery cells on the bottom of the lower housing; and Directly disposing the plurality of battery cells in the lower housing in contact with the second adhesive resin.

14. The manufacturing method according to claim 11, wherein, The lower 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 together with the pair of first outer walls defining an inner space of the battery pack housing; 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, wherein a wiring structure is disposed on the longitudinal beam, and the wiring structure is electrically connected to the plurality of battery cells, and an additional radiator is disposed in the longitudinal beam.

15. The manufacturing method according to claim 14, 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 further disposed in the table surface portion.

Images