Battery pack and device including same

Abstract

A battery pack according to an embodiment of the present invention includes: a plurality of battery cell assemblies each including a battery cell stack formed by stacking a plurality of battery cells, the battery cell stack having both side surfaces and upper and lower surfaces, at least some of which are exposed; a lower pack frame on which the plurality of battery cell assemblies are mounted; and a cross beam formed inside the lower pack frame and extending between a pair of adjacent battery cell assemblies among the plurality of battery cell assemblies, wherein each of the battery cell assemblies includes a sub-cross beam in contact with at least one side surface of the battery cell stack, and the cross beam and the sub-cross beam are spaced apart from each other.

Description

Battery pack and device including same

[0001] Cross-citation with related application(s)

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0105715, filed August 11, 2023, and Korean Patent Application No. 10-2024-0106318, filed August 8, 2024, the entire contents of which are incorporated herein by reference.

[0003] The present invention relates to a battery pack and a device including the same, and more particularly, to a battery cell assembly including a battery cell stack in which a plurality of battery cells are stacked, and a battery pack having a CTP (Cell To Pack) structure that accommodates the battery cell stack within a pack frame, and a device including the same.

[0004] In particular, the present invention relates to a battery pack and a device including the same, which includes a sub-crossbeam positioned on at least one side of a battery cell stack, wherein the sub-crossbeam is spaced apart from a crossbeam inside a pack frame.

[0005] Recently, as the demand for portable electronic products such as laptops, video cameras, and mobile phones has rapidly increased, and the development of electric vehicles, energy storage batteries, robots, and satellites has been in full swing, research on high-performance secondary batteries capable of repeated charging and discharging is actively being conducted.

[0006] Currently commercially available secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium secondary batteries. Among these, lithium secondary batteries are attracting attention for their advantages, including virtually no memory effect compared to nickel-based batteries, free charging and discharging, a very low self-discharge rate, and high energy density.

[0007] These lithium secondary batteries primarily use lithium oxide and carbon materials as the positive and negative electrode active materials, respectively. Furthermore, the lithium secondary battery comprises a positive electrode plate and a negative electrode plate coated with the positive and negative electrode active materials, an electrode assembly in which the positive and negative electrode plates are positioned with a separator between them, and an outer case that seals and houses the electrode assembly together with an electrolyte.

[0008] Meanwhile, lithium secondary batteries can be classified into can-type secondary batteries, in which the electrode assembly is housed in a metal can, and pouch-type secondary batteries, in which the electrode assembly is housed in a pouch made of aluminum laminate sheet, depending on the shape of the battery case. Can-type secondary batteries can be further classified into cylindrical batteries and square batteries, depending on the shape of the metal can.

[0009] Here, the pouch of the pouch-type secondary battery can be broadly divided into a lower sheet and an upper sheet covering the lower sheet. At this time, an electrode assembly formed by stacking and winding a positive electrode, a negative electrode, and a separator is stored in the pouch. Then, after storing the electrode assembly, the edges of the upper sheet and the lower sheet are sealed by heat fusion or the like. In addition, electrode tabs drawn from each electrode are connected to electrode leads, and an insulating film may be added to the portion of the electrode lead that comes into contact with the sealing portion.

[0010] In this way, pouch-type secondary batteries offer the flexibility to be configured in a variety of configurations. Furthermore, pouch-type secondary batteries offer the advantage of being able to produce batteries with the same capacity in a smaller volume and mass.

[0011] These lithium secondary batteries are used as battery modules or battery packs in which multiple battery cells are mounted on their own or in cartridges, etc., and then electrically connected to form a dense structure so that they can provide high voltage and high current.

[0012] 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 to ensure assembly tolerances for these components. Therefore, conventional battery packs may face limitations in increasing energy density.

[0013] 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, the process and structure for forming a cell stack using the aforementioned stacking frame, bolts, plates, and the like can be extremely complex.

[0014] Furthermore, conventional battery packs, with the module case housed within the pack case and the battery cells housed within the module case, present a challenge in ensuring excellent cooling performance. Specifically, if heat from the battery cells housed within the module case is discharged through the module case to the outside of the pack case, cooling efficiency can deteriorate and the cooling structure can become complex.

[0015] In particular, the battery pack must be able to control the swelling of the battery cells contained within the battery module, which occurs during the charging and discharging process. More specifically, during the repeated charging and discharging process, the internal electrolyte of the battery cells decomposes and gas is generated, causing the battery cells to swell, i.e., swelling. Failure to control this swelling of the battery cells can cause structural deformation of the battery module containing a large number of battery cells, and can also have a negative impact on the durability and performance of the battery module.

[0016] In particular, pure Si cells and high SiO content cells are recently used as battery cells for manufacturing high-capacity battery packs, and the degree of swelling of these cells is greater. In other words, in order to manufacture high-capacity battery modules and battery packs, it is essential to effectively control the swelling of battery cells within the battery module or battery pack.

[0017] Therefore, there is a need to develop technology for a battery pack that can effectively control the swelling of battery cells while increasing space efficiency.

[0018] The problem to be solved by the present invention is to provide a battery cell assembly including a battery cell stack in which a plurality of battery cells are stacked, a battery pack having a CTP (Cell To Pack) structure that accommodates the battery cell assembly inside a pack frame, and a device including the same.

[0019] In particular, the present invention provides a battery pack and a device including the same, which includes a sub-crossbeam positioned on at least one side of a battery cell stack, wherein the sub-crossbeam is spaced apart from a crossbeam inside a pack frame.

[0020] The problems to be solved by the present invention are not limited to the problems described above, and problems not mentioned can be clearly understood by a person having ordinary skill in the art to which the present invention pertains from this specification and the attached drawings.

[0021] According to one embodiment of the present invention, a battery pack comprises: a battery cell stack formed by stacking a plurality of battery cells, each of which comprises a plurality of battery cell assemblies, wherein at least a portion of both side surfaces and an upper and lower surface of the battery cell stack are exposed; a lower pack frame on which the plurality of battery cell assemblies are mounted; and a cross beam formed inside the lower pack frame and extending along between a pair of adjacent battery cell assemblies among the plurality of battery cell assemblies, wherein the battery cell assembly comprises a sub-cross beam that contacts at least one side surface of the battery cell stack, and the cross beam and the sub-cross beam are spaced apart from each other.

[0022] The above battery cell assembly further includes a busbar frame positioned at the front and rear sides of the battery cell stack, and at least one first coupling hole is formed at both ends of the sub-crossbeam in a portion overlapping the busbar frame, and the sub-crossbeam and the busbar frame can be fixed to each other through the first coupling hole.

[0023] The above sub-crossbeam and the above busbar frame may be bolted to each other.

[0024] The above sub-crossbeam may include a main body portion and a bending portion, the main body portion extending along a side surface of the battery cell stack, one end of the bending portion may be connected to an upper end of the main body portion, and the other end of the bending portion may extend toward an upper portion of the crossbeam.

[0025] The other end of the above-mentioned bending portion may overlap with the upper portion of the above-mentioned crossbeam.

[0026] The other end of the above-mentioned bending portion has at least one second joining hole formed in a portion overlapping the upper portion of the crossbeam, and the other end of the above-mentioned bending portion and the upper portion of the crossbeam can be fixed to each other through the second joining hole.

[0027] The other end of the above-mentioned bending portion and the upper portion of the above-mentioned crossbeam may be bolted to each other.

[0028] The height of the above crossbeam may be less than the height of the lower pack frame.

[0029] The sum of the height of the crossbeam and the thickness of the bending portion may be equal to or less than the height of the lower pack frame.

[0030] The above sub-crossbeam includes a first sub-crossbeam and a second sub-crossbeam, and the first sub-crossbeam can contact one side of the battery cell stack, and the second sub-crossbeam can contact the other side of the battery cell stack.

[0031] The above battery cell assembly further includes a first thermal resin layer applied between the lower surface of the battery cell stack and the lower pack frame, and the first thermal resin layer may extend to the lower portion of the sub crossbeam.

[0032] The above battery cell assembly includes a second thermal resin layer applied to an upper portion of the battery cell stack, and the second thermal resin layer may extend to an upper portion of the sub-crossbeam.

[0033] The above battery cell assembly may further include a pad member positioned between the battery cell stack and the sub-crossbeam.

[0034] A device according to another embodiment of the present invention comprises at least one battery pack as described above.

[0035] According to embodiments, the battery pack of the present invention and the device including the same have a battery cell assembly including a battery cell stack in which a plurality of battery cells are stacked and a CTP (Cell To Pack) structure that accommodates the battery cell stack inside a pack frame, and have the advantage of having a higher energy density and simplifying the assembly process compared to a conventional battery pack.

[0036] In addition, the battery pack of the present invention and the device including the same include a sub-crossbeam positioned on at least one side of the battery cell stack, so that the fixing force of the battery cell assembly to the pack frame is improved, and the rigidity of the battery pack having a CTP structure can be further improved.

[0037] In addition, the battery pack of the present invention and the device including the same can effectively control the swelling phenomenon of the battery cell since the sub-crossbeams described above are spaced apart from the crossbeams inside the pack frame.

[0038] The effects of the present invention are not limited to the effects described above, and effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present invention pertains from this specification and the attached drawings.

[0039] FIG. 1 is a perspective view of a battery cell assembly according to one embodiment of the present invention.

[0040] Figure 2 is an exploded perspective view of the battery cell assembly of Figure 1.

[0041] FIG. 3 is a side view showing one of the battery cells included in the battery cell assembly of FIG. 1.

[0042] FIG. 4 is a perspective view showing a sub-crossbeam positioned on at least one side of the battery cell assembly of FIG. 1.

[0043] FIG. 5 is a perspective view showing a battery pack according to another embodiment of the present invention.

[0044] Figure 6 is a cross-sectional view schematically showing a portion of a cross-section cut along the zy plane of Figure 5.

[0045] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0046] In order to clearly explain the present invention, parts that are not related to the description are omitted, and the same reference numerals are used for identical or similar components throughout the specification.

[0047] Furthermore, the sizes and thicknesses of each component shown in the drawings are arbitrarily indicated for convenience of explanation, and thus the present invention is not necessarily limited to the illustrated components. In the drawings, the thicknesses are enlarged to clearly represent various layers and regions. Furthermore, in the drawings, the thicknesses of some layers and regions are exaggerated for convenience of explanation.

[0048] Additionally, throughout the specification, whenever a part is said to “include” a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0049] Additionally, throughout the specification, when we say "in plan", we mean when the target portion is viewed from above, and when we say "in cross section", we mean when the target portion is viewed from the side in a cross-section cut vertically.

[0050] Hereinafter, a battery cell assembly according to an embodiment of the present invention will be described.

[0051] FIG. 1 is a perspective view of a battery cell assembly according to one embodiment of the present invention. FIG. 2 is an exploded perspective view of the battery cell assembly of FIG. 1. FIG. 3 is a side view showing one of the battery cells included in the battery cell assembly of FIG. 1. FIG. 4 is a perspective view showing a sub-crossbeam positioned on at least one side of the battery cell assembly of FIG. 1.

[0052] Referring to FIGS. 1 and 2, the battery cell assembly (100) includes a battery cell stack (120) formed by stacking a plurality of battery cells (110). More specifically, the battery cell stack (120) may be formed by stacking a plurality of battery cells (110) so that they can be electrically connected to each other. Here, the number of battery cells (110) constituting the battery cell stack (120) may be adjusted as needed.

[0053] In addition, at least a portion of both sides and the upper and lower surfaces of the battery cell stack (120) may be exposed. More specifically, unlike a conventional battery module having a structure in which the battery module is modularized by being housed inside a separate module case, the battery cell assembly (110) does not house the battery cell stack (120) inside a separate module case, and may be housed in the lower pack frame (1100, FIG. 5) with at least a portion of both sides and the upper and lower surfaces of the battery cell stack (120) exposed.

[0054] Accordingly, the battery cell assembly (100) according to the present embodiment does not require additional components such as a module case, unlike conventional battery modules or packs. That is, since the space occupied by the corresponding components in the present embodiment is eliminated, the battery cells can occupy more space, thereby improving energy density, reducing the overall volume or weight, and simplifying the manufacturing process.

[0055] Additionally, in the battery cell assembly (100), the lower portion of the battery cell stack (120) may be exposed. That is, when the battery cell assembly (100) is accommodated in the lower pack frame (1100, FIG. 5) described below, the lower portion of the battery cell (110) included in the battery cell stack (120) may be exposed toward the bottom surface of the lower pack frame (1100, FIG. 5).

[0056] Accordingly, in the battery cell assembly (100) according to the present embodiment, the lower portion of the battery cell (110) included in the battery cell stack (120) can directly contact the bottom surface of the lower pack frame (1100, FIG. 5), so that the cooling performance of the battery pack (1000, FIG. 5) can be further improved. That is, the heat emitted from the battery cell (110) is directly transferred to the lower pack frame (1100, FIG. 5), so that the cooling performance of the battery pack (1000, FIG. 5) can be further improved. In this case, since a separate cooling structure does not need to be provided between the battery cell (110) and the lower pack frame (1100, FIG. 5), efficient cooling performance can be implemented.

[0057] Referring to FIGS. 2 and 3, in the battery cell assembly (100), the battery cell (110) may be a pouch-type battery cell. This pouch-type battery cell may be formed by housing an electrode assembly in a pouch case made of a laminate sheet including a resin layer and a metal layer, and then bonding the outer periphery of the pouch case. This battery cell (110) may be formed in a rectangular sheet structure. Specifically, the battery cell (110) according to the present embodiment has a structure in which two electrode leads (111, 112) face each other and protrude from one end (114a) and the other end (114b) of the battery body (113), respectively. The battery cell (110) may be manufactured by bonding both ends (114a, 114b) of the battery case (114) and one side (114c) connecting them while housing an electrode assembly (not shown) in the battery case (114). In other words, the battery cell (110) according to one embodiment of the present invention has a total of three sealing portions, and the sealing portions are structured to be sealed by a method such as fusion, and the remaining other side may be formed as a connecting portion (115).

[0058] However, the battery cell (110) described above is an exemplary structure, and a unidirectional battery cell in which two electrode leads protrude in the same direction is also possible.

[0059] These battery cells (110) may be configured in multiple pieces, and the multiple battery cells (110) may be stacked so as to be electrically connected to each other to form a battery cell stack (120). In particular, as illustrated in FIG. 2, the multiple battery cells (110) may be stacked in a direction parallel to the y-axis. The battery case (114) is generally configured with a laminate structure of a resin layer / metal film layer / resin layer. For example, when the surface of the battery case is configured with an O(oriented)-nylon layer, when a plurality of battery cells are stacked to form a medium- or large-sized battery module, there is a tendency for the battery case to easily slip due to external impact. Therefore, in order to prevent this and maintain a stable stacked structure of the battery cells, an adhesive material such as a pressure-sensitive adhesive such as a double-sided tape or a chemical adhesive that is bonded by a chemical reaction during bonding may be attached to the surface of the battery case to form the battery cell stack (120).

[0060] As another example, unlike FIG. 3, the battery cell (110) may be a square battery cell or a cylindrical battery cell in the form of a jelly roll. However, if it is of a form that can form a battery cell stack (120) including a large number of battery cells (110) in a limited space within the battery cell assembly (100), it may be applied to the present embodiment.

[0061] Meanwhile, the battery cell assembly (100) according to the present embodiment may further include a first end plate (310) and a second end plate (320) positioned respectively on one side and the other side of the battery cell stack (120); a first bus bar frame (410) positioned between the battery cell stack (120) and the first end plate (310); and a second bus bar frame (420) positioned between the battery cell stack (120) and the second end plate (320).

[0062] More specifically, a first bus bar frame (410) and a first end plate (310) may be sequentially positioned on one side in the direction in which one electrode lead (111) of a battery cell (110) protrudes (x-axis direction), and a second bus bar frame (420) and a second end plate (320) may be sequentially positioned on the other side in the direction in which the other electrode lead (112) of the battery cell (110) protrudes (-x-axis direction).

[0063] The first busbar frame (410) and the second busbar frame (420) can be arranged to cover the front and rear sides of the battery cell stack, respectively, corresponding to the direction in which the electrode leads (111, 112) protrude (x-axis direction and -x-axis direction).

[0064] The first end plate (310) and the second end plate (320) may be arranged to cover one side of the first busbar frame (410) and one side of the second busbar frame (420), respectively. The first end plate (310) and the second end plate (320) may be plastic insulating covers having electrical insulation, and may protect other electrical components, including the busbar (500) and electrode leads (111, 112) located on the first busbar frame (410) and the second busbar frame (420), from the outside, while simultaneously blocking the possibility of a short circuit with the outside.

[0065] In another embodiment of the present invention, the first end plate (310) and the second end plate (320) may have high rigidity by including a metal material such as aluminum. However, in this case, it is preferable that a separate insulating cover be added between the first end plate (310) and the first busbar frame (410) and between the second end plate (320) and the second busbar frame (420).

[0066] The battery cell assembly (100) according to the present embodiment may further include busbars (500) mounted on the first busbar frame (410) and the second busbar frame (420). The second busbar frame (420) and the busbar (500) mounted thereon are not illustrated, but may have the same or similar structure as the first busbar frame (410).

[0067] The electrode leads (111, 112) of the battery cell (110) may be bent and connected to the bus bar (500) after passing through a lead slit formed in the first bus bar frame (410) or the second bus bar frame (420). More specifically, one electrode lead (111) may be connected to the bus bar (500) after passing through the lead slit of the first bus bar frame (410), and the other electrode lead (112) may be connected to the bus bar (500) after passing through the lead slit of the second bus bar frame (420). There is no particular limitation on the method of connecting the electrode leads (111, 112) and the bus bar (500), but, for example, welding may be performed.

[0068] In the same manner as above, the battery cells (110) constituting the battery cell stack (120) can be connected in series or in parallel with each other.

[0069] Meanwhile, although not specifically shown, the first busbar frame (410) or the second busbar frame (420) may be equipped with a terminal busbar for external power connection of the battery cell assembly (100) or a module connector for transmitting voltage and temperature sensing information.

[0070] Referring to FIGS. 2 and 4, the battery cell assembly (100) may include a sub-crossbeam (200) that contacts at least one side of the battery cell stack (120). More specifically, the sub-crossbeam (200) may include a first sub-crossbeam (210) and a second sub-crossbeam (220), and the first sub-crossbeam (210) may contact one side of the battery cell stack (120), and the second sub-crossbeam (220) may contact the other side of the battery cell stack (110). For example, the first sub-crossbeam (210) and the second sub-crossbeam (220) may be configured to be identical to each other, but symmetrical.

[0071] For example, the sub-crossbeam (200) may be made of steel, or more specifically, stainless steel (SUS). As another example, the cell cover may be made entirely of SUS.

[0072] Accordingly, in the battery cell assembly (100) according to the present embodiment, when the sub-crossbeam (200) is made of steel, the mechanical strength and rigidity are excellent, so that the stacked state of the plurality of battery cells (110) included in the battery cell stack (120) can be more stably supported. In addition, in this case, damage or breakage of the battery cells (110) due to external impact, such as a needle, can be more effectively prevented. In addition, in this case, handling of the battery cells (110) can be made easier.

[0073] Referring to FIG. 4, the sub-crossbeam (200) may include a main body (201) and a bending portion (205). Here, the main body (201) and the bending portion (205) may be connected to each other. Here, the main body (201) and the bending portion (205) may be integrated with each other or may be fixed to each other by a separate joining / bonding method such as welding.

[0074] More specifically, the main body (201) may extend along the side of the battery cell stack (120). Here, the main body (201) may have a size equal to or larger than the side of the battery cell stack (120).

[0075] In the sub-crossbeam (200), at least one first coupling hole (201h) may be formed at both ends of the sub-crossbeam (200). More specifically, at least one first coupling hole (201h) may be formed at both ends of the main body (201) of the sub-crossbeam (200). Here, at least one first coupling hole (201h) may be formed at a portion where the main body (201) of the sub-crossbeam (200) and the busbar frame (410, 420) overlap. That is, the sub-crossbeam (200) and the busbar frame (410, 420) may be fixed to each other through the first coupling hole (201h).

[0076] For example, the sub-crossbeam (200) and the busbar frame (410, 420) may be bolted to each other. Here, although not shown in FIGS. 2 and 4, the sub-crossbeam (200) and the busbar frame (410, 420) may be fastened to each other as the long bolt member is inserted into the first coupling hole (201h).

[0077] As another embodiment of the present invention, the sub-crossbeam (200) may be fixed to the end plate (310, 320) through the first coupling hole (201h). In this case, in the sub-crossbeam (200), the position of the first coupling hole (201h) may be changed to a portion where the main body (201) and the end plate (310, 320) overlap.

[0078] Accordingly, the battery cell assembly (100) according to the present embodiment further includes a sub-crossbeam (200) positioned on one side of the battery cell stack (120), thereby additionally securing the rigidity of the battery cell assembly (100), and stably maintaining the stacked state while protecting the battery cells (110) included in the battery cell stack (120) from external impact.

[0079] In addition, one end of the bending portion (205) may be connected to the upper end of the main body portion (201), and the other end of the bending portion (205) may extend in the opposite direction toward the battery cell stack (120). More specifically, the other end of the bending portion (205) may extend toward the upper portion of a cross beam (1200, FIG. 5) formed in the lower pack frame (1100) described below. That is, the other end of the bending portion (205) may overlap the upper portion of the cross beam (1200, FIG. 5).

[0080] In the sub-crossbeam (200), at least one second coupling hole (205h) may be formed in the bending portion (205). More specifically, at least one second coupling hole (205h) may be formed at the other end of the bending portion (205). Here, at least one second coupling hole (205h) may be formed at a portion where the other end of the bending portion (205) and the upper portion of the crossbeam (1200, FIG. 5) overlap. That is, the other end of the bending portion (205) and the upper portion of the crossbeam (1200, FIG. 5) may be fixed to each other through the second coupling hole (205h).

[0081] For example, the other end of the bending portion (205) and the upper part of the cross beam (1200, FIG. 5) may be bolted to each other. Here, although not shown in FIGS. 2 and 4, the other end of the bending portion (205) and the upper part of the cross beam (1200, FIG. 5) may be fastened to each other as the long bolt member is inserted into the second coupling hole (205h).

[0082] Accordingly, the battery cell assembly (100) according to the present embodiment further includes a sub-crossbeam (200) positioned on one side of the battery cell stack (120), thereby additionally securing the rigidity of the battery cell assembly (100), and stably maintaining the stacked state while protecting the battery cells (110) included in the battery cell stack (120) from external impact.

[0083] In addition, the battery cell assembly (100) according to the present embodiment has a sub-crossbeam (200) located on one side of the battery cell stack (120) and a crossbeam (1200, FIG. 5) that are fixed to each other, so that a fixing force between the battery cell assembly (100) and the lower pack frame (1100, FIG. 5) can be effectively secured.

[0084] In addition, through the fixation between the sub-crossbeam (200) and the crossbeam (1200, FIG. 5), a separate adhesive layer may be omitted at the bottom of the battery cell assembly (100), or even if an adhesive layer is added, a member having a relatively weak adhesive strength may be used. That is, when the adhesive layer is omitted between the bottom of the battery cell assembly (100) and the lower frame (1100, FIG. 5), or an adhesive layer having a weak adhesive strength is added, it is easy to release the bond between the battery cell assembly (100) and the lower pack frame (1100, FIG. 5), and replacement of the battery cell assembly (100) can also become easier.

[0085] Additionally, the battery cell assembly (100) may further include a pad member (150) positioned between the battery cell stack (120) and the sub-crossbeam (200). More specifically, the pad member (150) may be an insulating member, an insulating member, or a compression pad.

[0086] For example, when the pad member (150) is an insulating member, it is possible to block the electrical connection between the side of the battery cell stack (120) and external elements. As another example, when the pad member (150) is an insulating member, it is possible to prevent heat from being transmitted internally and externally when an abnormal phenomenon, such as a thermal runaway phenomenon, occurs in some of the battery cells (110) included in the battery cell stack (120). As another example, when the pad member (150) is a compression pad, it is possible to effectively control swelling that occurs in some of the battery cells (110) included in the battery cell stack (120).

[0087] In addition, the battery cell assembly (100) according to the present embodiment may further include a connecting member (600) positioned on the upper and lower sides of the battery cell stack (120), respectively, and connecting the first sub-crossbeam (210) and the second sub-crossbeam (220). That is, the battery cell assembly (100) may not have a structure in which the battery cell stack (120) is housed and sealed in a module housing, but may have a structure in which the first sub-crossbeam (210) and the second sub-crossbeam (220) are arranged on both sides of the battery cell stack (120), and the first sub-crossbeam (210) and the second sub-crossbeam (220) are fixed through the connecting member (600). That is, the battery cell assembly (100) according to the present embodiment has a simplified module housing structure compared to the prior art, and can be mounted directly on a battery pack (1000, FIG. 5) without a sealed module housing.

[0088] Accordingly, the battery cell assembly (100) according to the present embodiment omits the module housing structure, thereby increasing space utilization in the battery pack (1000, FIG. 5) unit described later and enabling improvement in overall energy density and weight reduction.

[0089] The connecting member (600) according to the present embodiment may be a member in the form of a metal band. More specifically, the connecting member (600) may be in the form of a band including an elastic metal material.

[0090] At least one of the upper side or the lower side of the battery cell stack (120) may have a plurality of connecting members (600) or may be provided singly. For example, a plurality of connecting members (600) may be provided at least one of the upper side or the lower side of the battery cell stack (120). FIG. 2 illustrates that a plurality of connecting members (600) are provided on both the upper side and the lower side of the battery cell stack (120). These connecting members (600) may be spaced apart from each other at regular intervals and positioned at the upper and lower sides of the battery cell stack (120), respectively. For example, FIG. 2 illustrates that three connecting members (600) are arranged at each of the upper and lower sides of the battery cell stack (120).

[0091] Since the connecting member (600) is a member that connects the first sub-crossbeam (210) and the second sub-crossbeam (220) to each other as described above, it may be in a form that extends from the first sub-crossbeam (210) to the second sub-crossbeam (220), that is, along the stacking direction of the battery cells (110). In other words, the connecting member (600) may extend in a direction parallel to the y-axis direction, so that one end may be connected to the first sub-crossbeam (210) and the other end may be connected to the second sub-crossbeam (220). This connecting member (600) may be fixed to the first sub-crossbeam (210) and the second sub-crossbeam (220) by welding.

[0092] Although not specifically illustrated, as another embodiment of the present invention, the connecting member (600) may further include a long bolt member that is connected to both ends of the connecting member (600) and the first sub-crossbeam (210) and the second sub-crossbeam (220). That is, the connecting member (600) may be connected to the first sub-crossbeam (210) and the second sub-crossbeam (220) by bolting rather than welding.

[0093] Accordingly, in the battery cell assembly (100) according to the present embodiment, the first sub-crossbeam (210) and the second sub-crossbeam (220) are also connected to each other by the connecting member (600), so that the rigidity of the battery cell assembly (100) can be additionally secured, and the connection between the battery cell stack (120) and the sub-crossbeam (200) can be maintained more stably.

[0094] Meanwhile, referring again to FIG. 2, the battery cell assembly (100) according to the present embodiment may further include an insulating sheet (800) positioned between the battery cell stack (120) and the connecting member (600) positioned on the upper side of the battery cell stack (120). The insulating sheet (800) is a thin electrically insulating sheet and may be positioned to cover the entire upper surface of the battery cell stack (120) to ensure electrical insulation of the upper side of the battery cell stack (120). This insulating sheet (800) may be an insulating film or an insulating tape, and may have a thickness of 0.1 mm or less.

[0095] Fig. 5 is a perspective view showing a battery pack according to another embodiment of the present invention. Fig. 6 is a cross-sectional view schematically showing a portion of a cross-section taken along the zy plane of Fig. 5.

[0096] Referring to FIGS. 5 and 6, a battery pack (1000) according to one embodiment of the present invention may include a lower pack frame (1100) on which a plurality of battery cell assemblies (100) are mounted, and a cross beam (1200) formed inside the lower pack frame (1100) and extending along between a pair of adjacent battery cell assemblies (100) among the plurality of battery cell assemblies (100). Here, the cross beam (1200) may be fixed to the bottom surface (1100F) of the lower pack frame (1100) by a joining method such as welding, or may be integrated with each other.

[0097] The battery pack (1000) may further include an upper pack frame (not shown) positioned above the battery cell assembly (100), although not shown in FIG. 5. Here, the lower pack frame (1100) and the upper pack frame (not shown) may be joined at their contacting surfaces by a method such as welding or adhesion, thereby sealing the inside of the battery pack (1000). However, the present invention is not limited thereto, and the pack frame of the battery pack (1000) may include an upper pack frame having an open bottom and a lower pack frame covering the lower portion of the upper pack frame. For example, the lower pack frame (1100) and the upper pack frame (not shown) may be made of a plastic or metal material. In addition, the pack case may employ various exterior materials of battery packs known at the time of filing of the present invention.

[0098] Referring to FIGS. 5 and 6, the sub-crossbeam (200) and the crossbeam (1200) included in the battery cell assembly (100) may be spaced apart from each other. More specifically, the sub-crossbeam (200) and the crossbeam (1200) of the battery cell assembly (100) may be spaced apart from each other by a predetermined gap (G).

[0099] Accordingly, in the battery pack (1000) according to the present embodiment, the battery cell assembly (100) is spaced apart from the lower pack frame (1100) by a predetermined gap (G), so that swelling occurring in some of the battery cells (110) included in the battery cell assembly (100) can be effectively controlled. That is, even if some of the battery cells (110) swell due to the swelling phenomenon, the pressure applied to other battery cells (110) in which the swelling phenomenon has not occurred can be relatively reduced through the predetermined gap (G), and structural deformation of the battery cell assembly (100) can be prevented.

[0100] In the battery pack (1000) according to the present embodiment, the upper portion of the cross beam (1200) may further include a mounting hole (1200H) formed at the same position as the second coupling hole (205h) included in the sub cross beam (200) of the battery cell assembly (100). That is, the other end of the above-described bending portion (205) and the mounting hole (1200H) of the cross beam (1200) may be bolted to each other. Here, although not illustrated in FIG. 5, as a long bolt member is inserted into the second coupling hole (205h) and the mounting hole (1200H), the other end of the bending portion (205) and the upper portion of the cross beam (1200) may be fastened to each other.

[0101] Additionally, the height of the crossbeam (1200) may be smaller than the height of the lower pack frame (1100). The sum of the height of the crossbeam (1200) and the thickness of the bending portion (205) may be equal to or smaller than the height of the lower pack frame (1100).

[0102] Accordingly, in the battery pack (1000) according to the present embodiment, even if the other end of the bent portion (205) of the sub-crossbeam (200) included in the battery cell assembly (100) partially overlaps with the upper portion of the crossbeam (1200), the height or size of the battery pack (1000) may not be affected, and the space efficiency of the battery pack (1000) may be increased.

[0103] Referring to FIGS. 2, 5, and 6, the battery cell assembly (100) according to the present embodiment may further include a thermal resin layer (900) positioned between the battery cell stack (120) and the lower pack frame (1100). More specifically, the thermal resin layer (900) may be positioned between the cooling unit (710) positioned on the bottom surface of the lower pack frame (1100) and the battery cell stack (120). However, the cooling unit (710) may be omitted as shown in FIG. 6.

[0104] For example, the battery cell assembly (100) further includes a first thermal resin layer (900B) applied between the lower surface of the battery cell stack (120) and the lower pack frame (1100), and the first thermal resin layer (900B) may extend to the lower portion of the sub crossbeam (200). In addition, the battery cell assembly (100) includes a second thermal resin layer (900A) applied to the upper portion of the battery cell stack (120), and the second thermal resin layer (900A) may extend to the upper portion of the sub crossbeam (200).

[0105] The thermal resin layer (900) may be formed by curing a thermal resin that has been applied or injected. The thermal resin may include a thermally conductive adhesive material, and specifically, may include at least one of a silicone material, a urethane material, and an acrylic material. The thermal resin may be in a liquid state when applied or may be cured after application to fix one or more battery cells (110) constituting the battery cell stack (120). In addition, it has excellent thermal conductivity characteristics, and thus can quickly transfer heat generated from the battery cells (110) to the lower pack frame (1100, FIG. 5).

[0106] Accordingly, in the battery cell assembly (100) according to the present embodiment, if a thermal resin layer (900) is further included on the upper or lower portion of the battery cell stack (120), the cooling performance of the battery pack (1000) can be further improved.

[0107] In addition, as shown in FIGS. 2 and 5, when connecting members (600) are formed on the upper and lower portions of the battery cell assembly (100), the thermal resin layer (900) can be placed in the space between the connecting members (600) that are spaced apart from each other.

[0108] In this case, by placing a thermal resin layer (900) in the space between the mutually spaced connecting members (600), the increase in height can be minimized, thereby reducing space loss in the height direction and increasing the energy density of the battery pack.

[0109] In the battery pack (1000) according to the present embodiment, referring to FIG. 5, the battery pack (1000) according to the present embodiment further includes a heat sink (700B) including at least one cooling unit (710) having a coolant flowing therein, and the heat sink (700B) may be positioned at the bottom of the battery cell assembly (100). However, the present invention is not limited thereto, and the heat sink may also be positioned at the top of the battery cell assembly (100), or the heat sink (700B) described above may be omitted, as in FIG. 6.

[0110] The heat sink (700B) may include at least one cooling section (710) having a coolant flowing therein. Here, the cooling section (710) of the heat sink (700B) may be located below the first thermal resin layer (900B) described above.

[0111] For example, the cooling unit (710) may be a tube member having an internal space formed therein, and this internal space may be a space in which a refrigerant flows. The refrigerant may be cooling water, and the heat sink (700B) according to the present embodiment may be a water-cooled cooling structure.

[0112] Accordingly, in the battery pack (1000) according to the present embodiment, if a heat sink (700B) formed on the lower pack frame (1100) is further included, the cooling performance of the battery pack (1000) can be further improved.

[0113] As another example, when a connecting member (600) is formed at the upper and lower portions of a battery cell assembly (100), as shown in FIGS. 2 and 5, the cooling member (710) of the heat sink (700B) is located on one side of the connecting member (600) at the lower portion of the battery cell assembly (100). Specifically, the cooling member (710) of the heat sink (700B) may be placed in the space between connecting members (600) that are spaced apart from each other.

[0114] Accordingly, by arranging the heat sink (700B) in the space between the mutually spaced connecting members (600), the cooling structure can be arranged while minimizing the increase in height, thereby reducing the space loss in the height direction and increasing the energy density of the battery pack.

[0115] The battery cell assembly and battery pack containing the same described above can be applied to various devices. These devices include, but are not limited to, means of transportation such as electric bicycles, electric vehicles, and hybrid vehicles. However, the present invention is not limited thereto and can be applied to various devices that can utilize the battery cell assembly and battery pack containing the same, and this also falls within the scope of the present invention.

[0116] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

[0117] [Explanation of symbols]

[0118] 100: Battery cell assembly

[0119] 110: Battery cell

[0120] 120: Battery cell stack

[0121] 150: Absence of pad

[0122] 200: Sub-crossbeam

[0123] 201: Main Body

[0124] 205: Bend section

[0125] 210: 1st sub-crossbeam

[0126] 220: Second sub-crossbeam

[0127] 300: End Plate

[0128] 410, 420: Busbar frame

[0129] 600: Absence of connection

[0130] 900: Thermal resin layer

[0131] 1000: Battery Pack

[0132] 1100: Lower pack frame

[0133] 1200: Crossbeam

Claims

1. A plurality of battery cell assemblies, each including a battery cell laminate formed by laminating a plurality of battery cells, wherein at least a portion of both sides and the upper and lower surfaces of the battery cell laminate are exposed; A lower pack frame on which the plurality of battery cell assemblies are mounted; and A cross beam formed within the lower pack frame and extending along between a pair of adjacent battery cell assemblies among the plurality of battery cell assemblies, The above battery cell assembly includes a sub-crossbeam that contacts at least one side of the battery cell stack, A battery pack in which the above crossbeam and the above sub-crossbeam are spaced apart from each other.

2. In paragraph 1, The above battery cell assembly further includes a bus bar frame positioned at the front and rear sides of the battery cell stack, At least one first joining hole is formed at both ends of the above sub-crossbeam in a portion overlapping the busbar frame, A battery pack in which the above sub-crossbeam and the above busbar frame are fixed to each other through the first joining hole.

3. In paragraph 2, A battery pack in which the above sub-crossbeam and the above busbar frame are bolted to each other.

4. In paragraph 1, The above sub-crossbeam includes a main body and a bending part, The above main body part extends along the side of the battery cell stack, A battery pack in which one end of the above-mentioned bending portion is connected to the upper end of the above-mentioned main body portion, and the other end of the above-mentioned bending portion extends toward the upper portion of the above-mentioned crossbeam.

5. In paragraph 4, A battery pack in which the other end of the above-mentioned bend overlaps the upper portion of the above-mentioned crossbeam.

6. In paragraph 5, The other end of the above-mentioned bend portion has at least one second joining hole formed in a portion that overlaps the upper portion of the above-mentioned cross beam, A battery pack in which the other end of the above-mentioned bending portion and the upper portion of the above-mentioned cross beam are fixed to each other through the second joining hole.

7. In paragraph 6, A battery pack in which the other end of the above-mentioned bending portion and the upper portion of the above-mentioned cross beam are bolted to each other.

8. In paragraph 4, A battery pack wherein the height of the above crossbeam is smaller than the height of the lower pack frame.

9. In paragraph 8, A battery pack wherein the sum of the height of the crossbeam and the thickness of the bending portion is equal to or smaller than the height of the lower pack frame.

10. In paragraph 1, The above sub-crossbeam includes a first sub-crossbeam and a second sub-crossbeam, A battery pack wherein the first sub-crossbeam contacts one side of the battery cell stack, and the second sub-crossbeam contacts the other side of the battery cell stack.

11. In paragraph 1, The above battery cell assembly further includes a first thermal resin layer applied between the lower surface of the battery cell stack and the lower pack frame, A battery pack wherein the first thermal resin layer extends to the lower portion of the sub-crossbeam.

12. In Article 11, The above battery cell assembly includes a second thermal resin layer applied on top of the battery cell stack, A battery pack wherein the second thermal resin layer extends to the upper portion of the sub-crossbeam.

13. In paragraph 1, A battery pack, wherein the battery cell assembly further includes a pad member positioned between the battery cell stack and the sub crossbeam.

14. A device comprising at least one battery pack according to paragraph 1.

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