KR102886203B1 - Battery pack and method of manufacturing the same - Google Patents

Abstract

A battery pack is provided, which is defined in a vertical coordinate system defined by a first direction, a second direction, and a third direction that are perpendicular to each other, and includes a plurality of battery cells stacked in the first direction and a pack case that accommodates the battery cells in an internal space, wherein the pack case includes an upper case and a lower case, the lower case includes an internal space that can accommodate the plurality of battery cells, and the upper case includes a heat sink that extends in the first direction.

Description

Battery pack and method of manufacturing the same

The present invention relates to a battery pack and a method for manufacturing the same, and more particularly, to a battery pack and a method for manufacturing the same, which control internal temperature rise and improve safety by quickly removing heat generated inside.

With the rapid growth in technological development and demand for various mobile devices, electric vehicles, and energy storage systems (ESS), interest in and demand for secondary batteries as an energy source are rapidly increasing. While nickel-cadmium and nickel-metal hydride batteries were previously widely used as secondary batteries, lithium secondary batteries are increasingly being used due to their virtually zero memory effect compared to nickel-based batteries, allowing for easy charging and discharging, extremely low self-discharge rates, and high energy density.

These lithium secondary batteries primarily use lithium oxide and carbon materials as the positive and negative electrode active materials, respectively. Lithium secondary batteries comprise an electrode assembly comprising positive and negative plates coated with the positive and negative electrode active materials, respectively, with a separator interposed between them, and an outer case, i.e., a battery case, that seals and encloses the electrode assembly together with an electrolyte.

Recently, battery packs have been widely used for powering or storing energy in medium- to large-sized devices such as electric vehicles and energy storage systems. Conventional battery packs typically include one or more battery modules within a pack case and a control unit, such as a battery management system (BMS), that controls the charging and discharging of the battery pack. Here, a battery module comprises a plurality of battery cells within the module case. In other words, in conventional battery packs, a plurality of battery cells (secondary batteries) are housed within the module case, each forming a battery module. One or more of these battery modules are housed within the pack case to form a battery pack.

In particular, pouch-type batteries have many advantages, such as being lightweight and having less dead space when stacked, but they also have vulnerabilities, such as being vulnerable to external impact and having somewhat poor assembly performance. Therefore, battery packs are typically manufactured by first modularizing a number of cells and then storing them inside a pack case. As a representative example, in the case of conventional battery packs, a number of pouch-type battery cells are first stored inside a module case to form a battery module, and then one or more of these battery modules are stored inside a pack case.

However, conventional battery packs such as these can be disadvantageous in terms of energy density. For example, during the process of modularizing multiple battery cells by housing them within a module case, various components such as the module case or stacking frame can unnecessarily increase the battery pack's volume or reduce the space occupied by the battery cells. Furthermore, not only can the space occupied by components such as the module case or stacking frame itself be reduced, but the space occupied by the battery cells can also be reduced due to the assembly tolerances required for these components. Therefore, conventional battery packs may face limitations in increasing energy density.

Furthermore, conventional battery packs can be disadvantageous in terms of assembly. Specifically, manufacturing a battery pack involves first modularizing multiple battery cells into a battery module, then housing the module in a pack case. This complicates the manufacturing process. Furthermore, as disclosed in the aforementioned prior art, the process and structure for forming a cell stack using a stacking frame, bolts, plates, and the like can be extremely complex.

Korean Patent Publication No. 10-2018-0092412

The first technical task to be achieved by the present invention is to provide a battery pack that controls internal temperature rise and improves safety by quickly removing heat generated internally.

The second technical task of the present invention is to provide a method for manufacturing a battery pack that controls internal temperature rise and improves safety by quickly removing heat generated internally.

In order to achieve the first technical task, the present invention provides a battery pack defined in a vertical coordinate system defined by a first direction, a second direction, and a third direction that are perpendicular to each other, including a plurality of battery cells stacked in the first direction and a pack case that accommodates the battery cells in an internal space, wherein the pack case includes an upper case and a lower case, the lower case includes an internal space capable of accommodating the plurality of battery cells, and the upper case includes a heat sink extending in the first direction.

In some embodiments, the heat sink may include a passage for cooling fluid extending in the first direction.

In some embodiments, the lower case includes a pair of first outer walls extending in the first direction; a pair of second outer walls extending in the second direction and defining an interior space of the pack case together with the pair of first outer walls; a longitudinal beam extending parallel to the first outer walls between the pair of first outer walls; and a bottom portion provided below the first outer walls, the second outer walls, and the longitudinal beam, wherein the lower case may include a heat sink extending in the first direction within the bottom portion.

In some embodiments, the plurality of battery cells may be bonded to the upper case by a first adhesive resin.

In some embodiments, the heat sink of the upper case may be positioned to overlap the first adhesive resin.

In some embodiments, the plurality of battery cells may be bonded to the upper case by a second adhesive resin, and the heat sink within the bottom portion of the lower case may be arranged to overlap with the second adhesive resin.

In some embodiments, a wiring structure may be provided on the upper portion of the longitudinal beam that is electrically connected to the plurality of battery cells, and an additional heat sink may be provided on the interior of the longitudinal beam.

In some embodiments, a heat sink may not be provided within the bottom portion of the lower portion of the longitudinal beam.

In some embodiments, each of the pair of first outer walls includes an outer wall body extending in the first direction and a mesa portion protruding from the outer wall body toward neighboring battery cells, and an additional heat sink extending in the first direction may be further provided within the mesa portion.

In some embodiments, the upper surface of the mesa portion may be lower than the upper surface of the outer wall body and have substantially the same height as the upper surface of the longitudinal beam.

The present invention provides a method for manufacturing a battery pack, comprising: arranging a plurality of battery cells directly within a lower case of a pack case in a vertical coordinate system defined by a first direction, a second direction, and a third direction that are perpendicular to each other; electrically connecting cell leads of at least two neighboring battery cells among the plurality of battery cells, which protrude in the second direction, using a bus bar; forming a layer of a first adhesive resin at a position corresponding to the plurality of battery cells on an upper case of the pack case; joining the upper case onto the lower case in which the plurality of battery cells are accommodated; and curing the first adhesive resin, wherein the step of electrically connecting the cell leads using the bus bar includes a step of welding and connecting each of the cell leads to the bus bar in the third direction, and wherein the upper case includes a heat sink extending in the first direction.

In some embodiments, the heat sink may be positioned to overlap the first adhesive resin.

In some embodiments, the step of directly arranging the plurality of battery cells within the lower case of the pack case may include the step of applying a second adhesive resin to a bottom portion within the lower case, at a location corresponding to the plurality of battery cells; and the step of directly arranging the plurality of battery cells within the lower case so as to be in contact with the second adhesive resin.

In some embodiments, the lower case includes a pair of first outer walls extending in the first direction; a pair of second outer walls extending in the second direction and defining an interior space of the pack case together with the pair of first outer walls; a longitudinal beam extending parallel to the first outer walls between the pair of first outer walls; and a bottom portion provided below the first outer walls, the second outer walls, and the longitudinal beam, wherein a wiring structure electrically connected to the plurality of battery cells is provided on an upper portion of the longitudinal beam, and an additional heat sink may be provided inside the longitudinal beam.

In some embodiments, each of the pair of first outer walls includes an outer wall body extending in the first direction and a mesa portion protruding from the outer wall body toward neighboring battery cells, and an additional heat sink extending in the first direction may be further provided within the mesa portion.

The battery pack of the present invention has the effect of improving safety and more easily controlling internal temperature rise by quickly removing heat generated internally.

FIG. 1 is an exploded perspective view showing a main part of a battery pack according to one embodiment of the present invention.
FIG. 2 is a perspective view showing a main portion of a lower case of a pack case according to one embodiment of the present invention.
FIG. 3 is a side cross-sectional view showing a main portion of the battery pack of FIG. 1 taken along line III-III'.
FIG. 4 is a perspective view illustrating a main part of a battery cell according to one embodiment of the present invention.
FIG. 5 is an enlarged partial view of a portion of a battery cell centered on a cell lead portion of the battery cell according to one embodiment of the present invention.
Figure 6 is an enlarged view of a portion of the battery cell viewed in the x direction, centered on the cell lead portion of the battery cell.
Figure 7 is an enlarged view of a portion of the battery cell viewed in the y direction, centered on the cell lead portion of the battery cell.
Figure 8 is an enlarged view of a portion of the battery cell viewed in the z direction, centered on the cell lead portion of the battery cell.
Figure 9 is a perspective view showing a pair of neighboring battery cells electrically connected by a busbar.
Fig. 10 is a cross-sectional view showing the second parts and the bus bar of Fig. 9 cut along the line XX'.
Figure 11 is a flowchart illustrating a method for manufacturing a battery pack according to one embodiment of the present invention.
FIGS. 12A to 12D are perspective views illustrating a method for manufacturing a battery pack according to one embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the embodiments of the present invention may be modified in various different forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. It is preferable to interpret that the embodiments of the present invention are provided to more completely explain the present invention to those of ordinary skill in the art. Like numbers refer to like elements throughout. Furthermore, various elements and areas in the drawings are schematically drawn. Therefore, the present invention is not limited by the relative sizes or spacings depicted in the accompanying drawings.

While terms like "first" and "second" may be used to describe various components, these components are not limited by these terms. These terms are used solely to distinguish one component from another. For example, a first component could be referred to as a "second component," and vice versa, without departing from the scope of the present invention.

The terminology used in this application is only used to describe specific embodiments and is not intended to limit the inventive concept. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the expressions "comprises" or "has" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, numbers, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Furthermore, it is to be understood that commonly used terms, such as those defined in dictionaries, should be interpreted to have a meaning consistent with their meaning within the relevant technical context, and should not be interpreted in an overly formal sense unless explicitly defined herein.

In some embodiments, where implementations are otherwise feasible, specific process sequences may be performed in a different order than described. For example, two processes described in succession may be performed substantially simultaneously, or in a reverse order from the described order.

In the accompanying drawings, variations in the shapes depicted may be expected, for example, depending on manufacturing techniques and/or tolerances. Therefore, embodiments of the present invention should not be construed as being limited to the specific shapes of the regions depicted herein, but should include, for example, changes in shapes resulting from the manufacturing process. All terms "and/or" used herein include each and every combination of one or more of the mentioned components. In addition, the term "substrate" used herein may mean the substrate itself, or a laminated structure including the substrate and a predetermined layer or film formed on the surface thereof. In addition, the "surface of the substrate" in this specification may mean the exposed surface of the substrate itself, or the outer surface of a predetermined layer or film formed on the substrate.

FIG. 1 is an exploded perspective view showing the main part of a battery pack (10) according to one embodiment of the present invention. In FIG. 1, the battery pack (10) is illustrated as being defined in a vertical coordinate system defined by a first direction along the x-axis, a second direction along the y-axis, and a third direction along the z-axis, which are all perpendicular to each other; however, the first direction, the second direction, and the third direction are not particularly limited as long as they are relatively perpendicular to each other.

Referring to FIG. 1, the battery pack (10) includes a plurality of battery cells (100) stacked in a first direction (e.g., x-axis direction) and a pack case (300) that accommodates the plurality of battery cells (100).

The pack case (300) has an internal space (330) capable of storing the plurality of battery cells (100). In some embodiments, the pack case (300) may include an upper case (310) and a lower case (320) defining the internal space (330).

Although not explicitly shown in FIG. 1, the pack case (300) may have wires disposed therein to electrically connect the plurality of battery cells (100) to an external electrical load.

In some embodiments, the lower case (320) may have a box shape with an open top and may house a plurality of battery cells (100) in the internal space (330). In addition, the upper case (310) may be configured in the form of a cover that covers the upper opening of the lower case (320). In some embodiments, the upper case (310) may also be configured in the form of a box with an open bottom.

The above pack case (300) may include a plastic or metal material. In addition, the pack case (300) may employ various exterior materials of battery packs known at the time of filing of the present invention.

The battery pack (10) may further include a battery management system. The battery management system (BMS) is mounted in the internal space of the pack case (300) and may be configured to control overall charging/discharging operations and data transmission/reception operations of the battery cells (100). The battery management system may be provided for each pack, not each module. More specifically, the battery management system may be configured to control the charging/discharging state, power state, and performance state of the battery cells (100) through pack voltage and pack current.

The battery pack (10) may further include a battery disconnect unit. The battery disconnect unit (BDU) may be configured to control the electrical connection of battery cells to manage the power capacity and function of the battery pack (10). To this end, the battery disconnect unit may include a power relay, a current sensor, a fuse, and the like. The battery disconnect unit is also provided per pack unit, not per module unit, and various disconnect units known at the time of filing of the present invention may be employed.

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

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

Referring to FIGS. 1 to 3, the upper case (310) is configured to define an internal space (330) together with the lower case (320).

The upper case (310) may include a heat sink (315) extending in the first direction (e.g., in the x-axis direction) therein. The heat sink (315) may be, for example, a passage for a cooling fluid extending in the first direction (e.g., in the x-axis direction). The cooling fluid may be a liquid, a gas, or a mixture thereof. For example, the cooling fluid may be, but is not limited to, water, air, alcohol, nitrogen, or the like.

The battery cells (100) may be bonded to the upper case (310) by a first adhesive resin (318). Any material having both thermal conductivity and adhesiveness may be used as the first adhesive resin (318). In some embodiments, the first adhesive resin (318) may include an acrylic resin, a urethane resin, a silicone resin, or a mixture thereof.

The thickness of the first adhesive resin (318) may be about 0.8 mm to about 1.2 mm. If the thickness of the first adhesive resin (318) is too thin, it is difficult to expect sufficient heat dissipation effect and fixing force. If the thickness of the first adhesive resin (318) is too thick, the effect is saturated at the expense of increased costs, which is economically disadvantageous.

In some embodiments, the heat sink (315) may be positioned to overlap the first adhesive resin (318) in the third direction (e.g., the z-axis direction). By overlapping the heat sink (315) with the first adhesive resin (318), heat generated from the battery cells (100) can be quickly removed to the outside.

With continued reference to FIGS. 1 to 3, the lower case (320) includes a pair of first outer walls (321) extending in the first direction (e.g., in the x-axis direction). In addition, the lower case (320) includes a pair of second outer walls (322) extending in the second direction (e.g., in the y-axis direction) and defining an interior space (330) of the pack case (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 formed integrally.

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

In some embodiments, the longitudinal beam (323) may have a mesa structure. In some embodiments, an upper surface of the longitudinal beam (323) may be lower than an upper surface of the second outer walls (322). In some embodiments, a side wall of the longitudinal beam (323) may extend obliquely downward with respect to its upper surface. In other embodiments, a side wall of the longitudinal beam (323) may extend perpendicularly with respect to its upper surface. In some embodiments, the side wall of the longitudinal beam (323) may be configured to correspond to an edge shape of an adjacent battery cell (100).

The longitudinal beam (323) can define an internal space (330) in which battery cells (100) (see FIG. 1) can be accommodated together with an adjacent first outer wall (321) among the first outer walls (321).

In some embodiments, the lower case (320) may include two or more longitudinal beams (323). In some embodiments, the pack case (300) may include two or more longitudinal beams (323). When the lower case (320) includes two or more longitudinal beams (323), two adjacent longitudinal beams (323) may define an internal space (330) in which battery cells (100) (see FIG. 1) may be accommodated.

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

The mesa portion (3212) may extend in the first direction (e.g., in the x-axis direction) to meet the pair of second outer walls (322). In some embodiments, the mesa portion (3212) may be formed integrally with the outer wall body (3211) and/or the second outer walls (322).

The upper surface of the mesa portion (3212) may be lower than the upper surface of the second outer walls (322). In some embodiments, the upper surface of the mesa 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 mesa portion (3212) may be narrower than the width of the upper surface of the longitudinal beam (323).

In some embodiments, the sidewall of the mesa portion (3212) may extend obliquely downward relative to its upper surface. In other embodiments, the sidewall of the mesa portion (3212) may extend vertically relative to its upper surface. In some embodiments, the sidewall of the mesa portion (3212) may be configured to correspond to the edge shape of the adjacent battery cell (100).

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

In some embodiments, the wiring structure (350) may further include busbars (200) on the wiring substrate (352).

The above bus bar (200) may be any conductor that electrically connects two adjacent battery cells (100) in the first direction (e.g., the x-axis direction). This will be described in more detail later.

A heat sink (3251) may be provided within the longitudinal beam (323) that penetrates the longitudinal beam (323) in the first direction (e.g., in the x-axis direction). The heat sink (3251) may be, for example, a passage for a cooling fluid extending in the first direction (e.g., in the x-axis direction). The cooling fluid may be a liquid, a gas, or a mixture thereof. For example, the cooling fluid may be, but is not limited to, water, air, alcohol, nitrogen, or the like.

As illustrated in FIG. 3, the cell leads (110) of the battery cells (100) are connected to the bus bar (200) at the upper portion of the longitudinal beam (323), and a large amount of heat is generated at the portion where the cell leads (110) and the bus bar (200) are connected during operation of the battery pack (10). Therefore, since the heat sink (3251) penetrating the interior of the longitudinal beam (323) can quickly remove a large amount of generated heat, the temperature rise of the battery pack (10) can be controlled and the safety of the battery pack (10) can be improved.

The heat sink (3251) may be fluidly connected to a cooling fluid reservoir provided outside the pack case (300). In some embodiments, the cooling fluid reservoir may be configured to cool a fluid stored therein.

In some embodiments, a wiring structure (350) may also be provided on the upper surface of the mesa portion (3212) of the first outer walls (321). The wiring structure (350) on the mesa portion (3212) may also include a wiring substrate (352) and bus bars (200).

A heat sink (3252) may be provided within the mesa portion (3212) that penetrates the mesa portion (3212) in the first direction (e.g., in the x-axis direction). The heat sink (3252) may be, for example, a passage for a cooling fluid extending in the first direction (e.g., in the x-axis direction). The cooling fluid may be a liquid, a gas, or a mixture thereof. For example, the cooling fluid may be, but is not limited to, water, air, alcohol, nitrogen, etc.

In some embodiments, the cell leads (110) of the battery cells (100) are coupled to the bus bar (200) at the upper portion of the mesa portion (3212), and a large amount of heat is generated at the portion where the cell leads (110) and the bus bar (200) are coupled during operation of the battery pack (10). Therefore, the heat sink (3252) penetrating the interior of the mesa 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).

The heat sink (3252) may be fluidly connected to a cooling fluid reservoir provided outside the pack case (300). In some embodiments, the cooling fluid reservoir may be configured to cool a fluid stored therein.

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

In some embodiments, an additional heat sink (3253) may be further provided within the bottom portion (326) of the battery cells (100). The additional heat sink (3253) may be, for example, a passage for a cooling fluid extending in the first direction (e.g., in the x-axis direction). The cooling fluid may be a liquid, a gas, or a mixture thereof. For example, the cooling fluid may be, but is not limited to, water, air, alcohol, nitrogen, or the like.

The additional heat sink (3253) can quickly remove heat generated from charging and discharging the battery cells (100), thereby controlling the temperature rise of the battery pack (10) and improving the safety of the battery pack (10).

In some embodiments, a heat sink may not be provided within the bottom portion (326) of the lower portion of the longitudinal beam (323). In some embodiments, a heat sink may not be provided within the bottom portion (326) of the lower portion of the mesa portion (3212).

The battery cells (100) may be bonded to the lower case (320) by a second adhesive resin (328). Any material having both thermal conductivity and adhesiveness may be used as the second adhesive resin (328). In some embodiments, the second adhesive resin (328) may include an acrylic resin, a urethane resin, a silicone resin, or a mixture thereof.

The thickness of the second adhesive resin (328) may be about 0.8 mm to about 1.2 mm. If the thickness of the second adhesive resin (328) is too thin, it is difficult to expect sufficient heat dissipation effect and fixing force. If the thickness of the second adhesive resin (328) is too thick, the effect is saturated at the expense of increased costs, which is economically disadvantageous.

In some embodiments, the heat sink (3253) may be positioned to overlap the second adhesive resin (328) in the third direction (e.g., the z-axis direction). By overlapping the heat sink (3253) with the second adhesive resin (328), heat generated from the battery cells (100) can be quickly removed to the outside.

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

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

In some embodiments, the battery cell (100) may be a pouch-shaped battery cell, but the present invention is not limited thereto. In some embodiments, the battery cell (100) may be a square battery cell.

In some embodiments, the battery cell (100) may have a thin plate-shaped body, and may preferably have a pouch cell structure. The pouch cell may have a structure in which a positive electrode, a separator, and a negative electrode are alternately stacked to form the electrode assembly (101), and an electrode tab is extended to at least one side and connected to the cell lead (110). The positive and negative electrodes may be manufactured by applying a slurry of an electrode active material, a binder resin, a conductive agent, and other additives to at least one surface of a current collector. For the positive electrode, a typical positive electrode active material such as a lithium-containing transition metal oxide may be used, and for the negative electrode, a typical negative electrode active material such as lithium metal, carbon material, and metal compound or a mixture thereof capable of absorbing and releasing lithium ions may be used. In addition, a typical porous polymer film used in a lithium secondary battery may be employed as the separator.

As the electrolyte accommodated in the cover (105) together with the electrode assembly (101), a typical lithium secondary battery electrolyte may be employed. The cover (105) is formed of a sheet material and has a receiving portion for accommodating the electrode assembly (101). Preferably, the cover (105) is formed by combining a first case and a second case, which are formed by processing a sheet material into a predetermined shape. The sheet material constituting the cover (105) has a multilayer structure in which an outermost outer resin layer made of an insulating material such as polyethylene terephthalate (PET) or nylon, a metal layer made of aluminum that maintains mechanical strength and prevents the penetration of moisture and oxygen, and an inner resin layer made of a polyolefin-based material that has thermal adhesiveness and serves as a sealant are laminated.

The sheet material forming the cover (105) may have a predetermined adhesive resin layer interposed between the inner resin layer and the metal layer, and between the outer resin layer and the metal layer, as needed. The adhesive resin layer is formed as a single layer or multiple layers for smooth adhesion between different materials, and the material is typically a polyolefin resin, or a polyurethane resin may be used for smooth processing, and a mixture of these may also be employed.

The battery cell (100) has two main surfaces (S1, S2) perpendicular to the first direction (e.g., x direction) as illustrated in FIG. 4. That is, the battery cell (100) may have a first main surface (S1) and a second main surface (S2) extending along the yz plane of FIG. 4 and being parallel to each other.

FIG. 5 is an enlarged partial view of a portion of a battery cell (100) centered on a cell lead (110) portion of the battery cell (100) according to one embodiment of the present invention.

Referring to FIG. 5, the cell lead (110) protrudes from one side of the cover (105) in the second direction (e.g., in the y-axis direction) and includes a first portion (111) and a second portion (112). The first portion (111) may be positioned relatively closer to the cover (105) than the second portion (112). In addition, the second portion (112) may be the leading end of the cell lead (110) in the second direction.

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

In some embodiments, the first part (111) may have a flat plate shape having a plane as a main plane that is generally perpendicular to the first direction (e.g., the x-axis direction). In some embodiments, the second part (112) may be configured as a plane that is perpendicular to the third direction (e.g., the z-axis direction). Here, the second part (112) being configured as a plane that is perpendicular to the third direction means that the upper surface and the lower surface of the second part (112) are perpendicular to the third direction and do not include a through hole within the upper surface and the lower surface. In some embodiments, the upper surface and the lower surface of the second part (112) may be perpendicular to the third direction and do not include a through hole within the upper surface and the lower surface. In some embodiments, the upper surface and the lower surface of the second part (112) may be perpendicular to the third direction and include a through hole within the upper surface and the lower surface.

Figure 6 is an enlarged view of a portion of the battery cell (100) viewed in the x direction, centered on the cell lead (110) portion of the battery cell (100).

Referring to FIG. 6, the first part (111) of the cell lead (110) has a first upper surface (111a) and a first lower surface (111b). In addition, the second part (112) of the cell lead (110) has a second upper surface (112a) and a second lower surface (112b). Here, the 'upper surface' and the 'lower surface' are relative concepts, and the one located relatively above can be defined as the 'upper surface', and the one located relatively below can be defined as the 'lower surface', or one of the two can be defined as the 'upper surface' and the other as the 'lower surface'.

A center line (CL) can be defined for the first portion (111). The center line (CL) is a straight line in the second direction (e.g., the y-axis direction) that divides the first portion (111) into two in the third direction (e.g., the z-axis direction).

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

In the third direction, the first portion (111) has a first dimension (H1) and the second portion (112) has a second dimension (H2) smaller than the first dimension (H1). The second dimension (H2) may be, for example, about 0.5% to about 50% of the first dimension (H1). In some embodiments, the second dimension (H2) can be 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%, about 8.5% to about 10% of the first dimension (H1), or a range between any two of these values.

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

Figure 7 is an enlarged view of a portion of the battery cell (100) viewed in the y direction, centered on the cell lead (110) portion of the battery cell (100).

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

If the second maximum dimension (d2) is too small compared to the first maximum dimension (d1), welding of the bus bar to be described later and the second portion (112) may not be easy. If 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., x-axis direction) may excessively increase, resulting in a decrease in energy density.

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

Figure 8 is an enlarged view of a portion of the battery cell (100) viewed in the z direction, centered on the cell lead (110) portion of the battery cell (100).

Referring to FIG. 8, the projection of the second portion (112) onto a plane (e.g., an xy plane) perpendicular to the third direction (e.g., a z-axis direction) may have a circular shape. In some embodiments, the projection of the second portion (112) onto the xy plane may have an elliptical shape, a polygonal shape (e.g., a square, a pentagon, a hexagon, etc.), or any other arbitrary shape other than a circular shape. However, it may be advantageous for the projection to have a circular shape in terms of the diversity of welding methods that can be used for welding with a bus bar in the future, structural stability, ease of handling, etc.

In some embodiments, when the projection is circular, the second portion (112) may have the shape of a cylinder or a truncated cone. When the projection is polygonal, the second portion (112) may have the shape of a polygonal column or a polygonal truncated pyramid.

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

If the projection area of the second part (112) is too small compared to the projection area of the first part (111), welding of the bus bar to be described later and the second part (112) may not be easy. If the projection area of the second part (112) is too large compared to the projection area of the first part (111), the weight of the battery cell (100) may increase unnecessarily.

Since the battery cells (100) have a plane shape in which the second portion (112) of the cell lead (110) is perpendicular to the third direction (e.g., the z-axis direction), it is possible to electrically interconnect the battery cells (100) after they are combined in the pack case (300). Therefore, the battery pack according to the embodiments of the present invention can be manufactured inexpensively due to a simple number of parts, has excellent productivity, and has a low risk of product failure.

Fig. 9 is a perspective view showing a pair of neighboring battery cells (100_1, 100_2) electrically connected by a bus bar (200).

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

The cell lead (110_1) of the first battery cell (100_1) and the cell lead (110_2) of the second battery cell (100_2) may be electrically connected by a bus bar (200). Specifically, the second part (112_1) of the first battery cell (100_1) and the second part (112_2) of the second battery cell (100_2) may be electrically connected by the bus bar (200).

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

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

The bus bar (200) may be provided on a wiring board (352) disposed on the upper portion of the longitudinal beam (323) as described with reference to FIGS. 2 and 3. In some embodiments, the bus bar (200) may be provided on a wiring board (352) disposed on the upper portion of the mesa portion (3212) as described with reference to FIGS. 2 and 3.

The cell lead (110_1) of the first battery cell (100_1) and the cell lead (110_2) of the second battery cell (100_2) may extend to the upper portion of the longitudinal beam (323). Specifically, the cell lead (110_1) of the first battery cell (100_1) and the cell lead (110_2) of the second battery cell (100_2) may be electrically connected to the bus bar (200) at the upper portion of the longitudinal beam (323).

Fig. 10 is a cross-sectional view showing the second parts (112_1, 112_2) and the bus bar (200) of Fig. 9 cut along the line X-X'.

Referring to FIG. 10, the bus bar (200) may have a concave recess (R) in a third direction (e.g., z-axis direction) at a portion overlapping the second portions (112_1, 112_2). In some embodiments, the recess (R) may be created as a result of welding the bus bar (200) and the second portions (112_1, 112_2) in the third direction. However, since the recess (R) is a result of the contact portion between the bus bar (200) and the second portions (112_1, 112_2) being partially melted and then solidified by welding, it may appear as traces of melting and solidification in some cases.

In Fig. 10, the recess (R) is shown as being formed continuously with the flat surface of the bus bar (200), but in some cases, a slight raised portion may be formed around the recess (R).

In some embodiments, depending on the welding method, the recess (R) may not be identified as a clear interface.

The battery pack (10) according to the embodiments of the present invention described above has the effect of more easily controlling the rise in internal temperature and improving safety by quickly removing heat generated internally.

Fig. 11 is a flowchart illustrating a method for manufacturing a battery pack (10) according to one embodiment of the present invention. Figs. 12a to 12d are perspective views illustrating a method for manufacturing a battery pack (10) according to one embodiment of the present invention.

Referring to FIGS. 11 and 12A, a plurality of battery cells (100) can be placed directly within a pack case (300) (S10). Here, placing the plurality of battery cells (100) directly within the pack case (300) means placing the plurality of battery cells (100) within the pack case (300) without configuring them as modules.

In some embodiments, the plurality of battery cells (100) may be individually placed within the pack case (300) one by one. In some other embodiments, the plurality of battery cells (100) may be stacked in groups of two or more and then placed within the pack case (300).

Before arranging the plurality of battery cells (100) in the pack case (300), a layer of a second adhesive resin (328) may be formed on the bottom of the lower case (320) of the pack case (300). The second adhesive resin (328) may include, for example, an acrylic resin, a urethane resin, a silicone resin, or a mixture thereof. The thickness of the layer of the second adhesive resin (328) may be from about 0.8 mm to about 1.2 mm. In some embodiments, the supply amount and supply position of the second adhesive resin (328) may be controlled so that the thickness of the second adhesive resin (328) after curing is from about 0.8 mm to about 1.2 mm. The layer of the second adhesive resin (328) may be formed at a position where the plurality of battery cells (100) are arranged.

Thereafter, the battery cells (100) can be placed directly within the lower case (320) so that the edges of the battery cells (100) facing the bottom of the lower case (320) come into contact with the layer of the second adhesive resin (328).

The method for arranging the above battery cells (100) within the pack case (300) is not particularly limited, and they may be arranged within the pack case (300) by any known method. The configuration of the lower case (320) has been described with reference to FIGS. 1 to 3, and thus a detailed description thereof will be omitted herein. In addition, the specific configuration of each battery cell (100) has been described with reference to FIGS. 4 to 10, and thus a detailed description thereof will be omitted herein.

Referring to FIGS. 11 and 12b, the cell leads (110_1, 110_2) protruding in the second direction (e.g., y-axis direction) of two neighboring battery cells (100) can be electrically connected to the bus bar (200) (S20). The cell leads (110_1, 110_2) can be connected to the bus bar (200) by welding in the third direction (e.g., z-axis direction).

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

Since the battery cells (100) have a plane shape in which the second portion (112) of the cell lead (110) is perpendicular to the third direction (e.g., the z-axis direction), it is possible to electrically interconnect the battery cells (100) after they are combined in the pack case (300). Therefore, the battery pack according to the embodiments of the present invention can be manufactured inexpensively due to a simple number of parts, has excellent productivity, and has a low risk of product failure.

Referring to FIGS. 11 and 12C, a first adhesive resin (318) is disposed on the plurality of battery cells (100) coupled with the bus (200) within the lower case (320) (S30). The first adhesive resin (318) may be provided on the upper edges of the battery cells (100) that are arranged to be stacked in the first direction (e.g., the x-axis direction). The first adhesive resin (318) does not necessarily need to form a thin film, and it is sufficient that the first adhesive resin (318) is provided in an amount and at an appropriate position so that the first adhesive resin (318) is distributed with an appropriate thickness and width when the upper case (310) is coupled to the lower case (320) later. The first adhesive resin (318) may include, for example, an acrylic resin, a urethane resin, a silicone resin, or a mixture thereof.

Referring to FIG. 11 and FIG. 12d, the upper case (310) can be combined on the lower case (320) in which the plurality of battery cells (100) are stored (S40).

Specifically, the pack case (300) can be sealed by bringing the upper case (310) and the lower case (320) into close contact with each other so that the first adhesive resin (318) is compressed by the upper case (310) and spreads to an appropriate width on the upper edge of the battery cells (100).

Afterwards, the first adhesive resin (318) can be cured (S50).

The battery pack (10) according to the embodiments of the present invention manufactured by the manufacturing method described above has the effect of more easily controlling the increase in internal temperature and improving safety by quickly removing the heat generated inside.

While the embodiments of the present invention have been described in detail above, those skilled in the art will appreciate that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention as defined in the appended claims. Therefore, modifications to future embodiments of the present invention will not depart from the scope of the invention.

10: Battery pack 100: Battery cell
101: Electrode assembly 105: Cover
110: Cell Lead 111: Part 1
111a: First upper surface 111b: First lower surface
112: Part 2 112a: Surface 2
112b: Second floor 200: Bus bar
300: Pack case 310: Upper case
315, 3251, 3252, 3253: Heat sink 318: First adhesive resin
320: Lower case 321: First outer wall
3211: Outer wall body 3212: Mesa
322: Second outer wall 323: Longitudinal beam
326: Bottom 328: Second adhesive resin
330: Internal space 350: Wiring structure
352: Wiring board CL: Center line
S1, S2: Main surface

Claims (15)

In a vertical coordinate system defined by a first direction, a second direction, and a third direction that are perpendicular to each other,
a plurality of battery cells stacked in the first direction; and
A pack case that stores the battery cells in an internal space;
Including,
The above pack case includes an upper case and a lower case,
The lower case includes an internal space capable of accommodating the plurality of battery cells,
The upper case includes a heat sink extending in the first direction,
The above lower case:
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 interior space of the pack case together with the pair of first outer walls;
a longitudinal beam extending parallel to the first outer walls between the pair of first outer walls; and
A floor portion provided on the lower portion of the first outer walls, the second outer walls, and the longitudinal beam;
Including,
A wiring structure electrically connected to the plurality of battery cells is provided on the upper portion of the longitudinal beam,
A battery pack having an additional heat sink provided inside the longitudinal beam. In the first paragraph,
A battery pack, wherein the heat sink includes a passage for cooling fluid extending in the first direction. In the first paragraph,
A battery pack characterized in that the lower case includes a heat sink extending in the first direction within the bottom portion. In the third paragraph,
A battery pack characterized in that the plurality of battery cells are bonded to the upper case by a first adhesive resin having a heat dissipation effect. In paragraph 4,
A battery pack, characterized in that the heat sink of the upper case is arranged to overlap with the first adhesive resin. In paragraph 4,
A battery pack characterized in that the plurality of battery cells are bonded to the upper case by a second adhesive resin, and the heat sink within the bottom portion of the lower case is arranged to overlap with the second adhesive resin. delete In the first paragraph,
A battery pack characterized in that no heat sink is provided within the bottom portion of the lower portion of the longitudinal beam. In the third paragraph,
Each of the above pair of first outer walls:
An outer wall body extending in the first direction; and
A mesa portion protruding from the outer wall body toward neighboring battery cells;
Including,
A battery pack characterized in that an additional heat sink extending in the first direction is further provided within the mesa portion. In paragraph 9,
A battery pack characterized in that the upper surface of the mesa portion is lower than the upper surface of the outer wall body and has substantially the same height as the upper surface of the longitudinal beam. In a vertical coordinate system defined by a first direction, a second direction, and a third direction that are perpendicular to each other,
A step of directly arranging multiple battery cells within the lower case of the pack case;
A step of electrically connecting the cell leads of at least two neighboring battery cells among the plurality of battery cells protruding in the second direction using a bus bar;
A step of placing a first adhesive resin on the plurality of battery cells coupled to the bus bar;
A step of joining an upper case onto the lower case in which the plurality of battery cells are stored; and
A step of curing the first adhesive resin;
Including,
The step of electrically connecting the cell leads using a bus bar includes the step of connecting each of the cell leads to the bus bar by welding in the third direction,
The upper case includes a heat sink extending in the first direction,
The above lower case:
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 interior space of the pack case together with the pair of first outer walls;
a longitudinal beam extending parallel to the first outer walls between the pair of first outer walls; and
A floor portion provided on the lower portion of the first outer walls, the second outer walls, and the longitudinal beam;
Including,
A wiring structure electrically connected to the plurality of battery cells is provided on the upper portion of the longitudinal beam,
A method for manufacturing a battery pack, wherein an additional heat sink is provided inside the longitudinal beam. In paragraph 11,
A method for manufacturing a battery pack, characterized in that the heat sink is arranged to overlap the first adhesive resin. In paragraph 11,
The step of directly arranging the plurality of battery cells within the lower case of the pack case is:
A step of applying a second adhesive resin to a position corresponding to the plurality of battery cells on the bottom of the lower case; and
A step of directly arranging the plurality of battery cells within the lower case so as to be in contact with the second adhesive resin;
A method for manufacturing a battery pack, characterized in that it includes: delete In paragraph 11,
Each of the above pair of first outer walls:
An outer wall body extending in the first direction; and
A mesa portion protruding from the outer wall body toward neighboring battery cells;
Including,
A method for manufacturing a battery pack, characterized in that an additional heat sink extending in the first direction is further provided within the mesa portion.