Battery pack and energy storage apparatus

Abstract

A battery pack according to one embodiment of the present invention may comprise: a cell module assembly including a battery cell stack in which a plurality of battery cells are stacked; a lower pack case including a bottom plate supporting a lower portion of the cell module assembly and a fixing plate extending upward from an edge of the bottom plate; an upper pack case covering the upper surface, both side surfaces, and the rear surface of the cell module assembly and coupled to the lower pack case; a lower fixing part formed on the fixing plate of the lower pack case; and an upper fixing part formed on the upper pack case, wherein at least a portion of the upper fixing part overlaps and is fixed to the lower fixing part when the lower pack case and the upper pack case are assembled.

Description

Battery packs and energy storage devices

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

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0005423, filed January 12, 2024, the entire contents of which are incorporated herein by reference.

[0003] The present invention relates to a battery pack and an energy storage device, and more particularly, to a battery pack and an energy storage device having minimized assembly tolerances during assembly of a battery pack case and increased energy density.

[0004] In modern society, the widespread use of portable devices like cell phones, laptops, camcorders, and digital cameras, as well as energy storage systems (ESS), has led to active development of related technologies. Furthermore, rechargeable secondary batteries are increasingly being used as power sources for electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (P-HEVs) to address air pollution issues caused by conventional gasoline-powered vehicles. This, in turn, heightens the need for further development of these batteries.

[0005] Currently commercialized secondary batteries include nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, and lithium secondary batteries. Among these, lithium secondary batteries are receiving the most attention due to their advantages of free charging and discharging, low self-discharge rate, and high energy density.

[0006] These secondary batteries are widely used not only in small devices like portable electronic devices, but also in medium- to large-scale devices like electric vehicles and energy storage systems (ESS), and their use is rapidly increasing. Furthermore, the use of residential battery packs for power storage has been on the rise recently.

[0007] Typically, when producing parts, dimensional deviations, or component tolerances, arise due to various factors, including machine precision, material, and temperature. Furthermore, when multiple parts are assembled, not only are environmental factors like the material and temperature of the produced parts affected, but also the cumulative tolerances of the individual parts, resulting in assembly tolerances, or component dimensional deviations.

[0008] Therefore, research is being conducted on a method to minimize assembly tolerances during assembly of a battery pack case and to further increase the energy density of a battery pack and / or energy storage system (ESS).

[0009] The purpose of the present invention is to provide a battery pack and energy storage device that can minimize assembly tolerance during assembly of a battery pack case and increase energy density.

[0010] However, the problems to be solved by the embodiments of the present invention are not limited to the problems described above and can be expanded in various ways within the scope of the technical ideas included in the present invention.

[0011] According to one embodiment of the present invention, a battery pack may include a cell module assembly including a battery cell stack in which a plurality of battery cells are stacked, a lower pack case including a bottom plate supporting a lower portion of the cell module assembly and a fixing plate extending upward from a rim of the bottom plate, an upper pack case covering an upper surface, both side surfaces, and a rear surface of the cell module assembly and coupled to the lower pack case, a lower fixing portion formed on the fixing plate of the lower pack case, and an upper fixing portion formed on the upper pack case and fixed to each other by overlapping at least a portion of the lower fixing portion when the lower pack case and the upper pack case are assembled.

[0012] The upper fixing portion may include a first upper overlapping portion that overlaps the lower fixing portion on one of the inner and outer surfaces of the lower fixing portion, and a second upper overlapping portion that overlaps the lower fixing portion on the other of the inner and outer surfaces of the lower fixing portion.

[0013] The second upper overlapping portion may be formed by being recessed inward from the first upper overlapping portion.

[0014] The first upper overlapping portion is formed by being recessed inward from the upper pack case, and at least a portion of the upper pack case can be spaced apart from the lower pack case by a predetermined distance.

[0015] The inner surface of the first upper overlapping portion may overlap with the outer surface of the lower fixing portion, and the outer surface of the second upper overlapping portion may overlap with the inner surface of the lower fixing portion.

[0016] The upper fixing portion further includes an upper cut portion formed by cutting a portion of a connecting portion between the first upper overlapping portion and the second upper overlapping portion upward, and a connecting portion formed in the remaining portion of the connecting portion to connect the first upper overlapping portion and the second upper overlapping portion, and when the lower pack case and the upper pack case are assembled, the lower fixing portion can be inserted into the upper cut portion.

[0017] The lower fixing portion includes a lower cut portion formed by being cut downward, and when the lower pack case and the upper pack case are assembled, the upper cut portion and the lower cut portion can be inserted into each other.

[0018] The upper fixing portion can intersect the lower fixing portion at the lower cut portion.

[0019] The lower fixing portion can intersect the upper fixing portion at the upper cut portion.

[0020] The width of the lower cut portion may be greater than or equal to the width of the connecting portion between the first upper overlapping portion and the second upper overlapping portion.

[0021] The upper fixing portion is formed at an end portion facing the lower pack case from the second upper overlapping portion, and may further include a guide portion inclined inward.

[0022] The battery pack may further include a fixing member that penetrates a portion where the lower fixing portion and the upper fixing portion overlap each other to fix the lower pack case and the upper pack case to each other.

[0023] The battery pack further includes an insulating sheet disposed between the cell module assembly and the upper pack case, and the upper pack case can be coupled to the lower pack case while the cell module assembly is covered by the insulating sheet.

[0024] The above insulating sheet can cover the upper part, both sides, and the rear part of the cell module assembly so that interference does not occur between the upper pack case and the cell module assembly when the lower pack case and the upper pack case are assembled.

[0025] The above cell module assembly further includes a pair of end plates arranged at opposite sides of the battery cell stack and at least one strap connecting the pair of end plates, and the lower pack case may include a drainage hole formed in a first area corresponding to a portion where the at least one strap is arranged.

[0026] The above drain hole may include a plurality of drain holes arranged along the extension direction of the at least one strap.

[0027] The lower pack case may further include a plurality of protrusions for spacing the cell module assembly and the drain hole.

[0028] The above plurality of protrusions may be formed in a second region other than the first region in the lower pack case.

[0029] An energy storage device according to one embodiment of the present invention may include a battery pack of the above-described embodiments.

[0030] Battery packs and energy storage devices according to embodiments of the present invention can minimize assembly tolerances during assembly of the battery pack case, maximize space efficiency within the battery pack case, and increase energy density. Accordingly, the quality of the battery pack and energy storage device can be improved.

[0031] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

[0032] FIG. 1 is a perspective view showing a battery pack according to one embodiment of the present invention.

[0033] Figure 2 is an exploded perspective view of the battery pack of Figure 1.

[0034] FIG. 3 is a perspective view showing a cell module assembly of the battery pack of FIG. 2.

[0035] FIG. 4 is a perspective view showing only the upper pack case and the lower pack case in the battery pack of FIG. 2.

[0036] Figure 5 is an enlarged perspective view of part A of Figure 4.

[0037] Figure 6 is an enlarged view of part A of Figure 4 from the side.

[0038] Figure 7 is an enlarged view of part A of Figure 4 from the lower surface.

[0039] Figure 8 is an enlarged perspective view of part B of Figure 4.

[0040] Figure 9 is a perspective view showing the portion where the upper pack case and the lower pack case are combined from the outside.

[0041] Figure 10 is a perspective view showing the internal portion of the upper pack case and the lower pack case combined.

[0042] Fig. 11 is a cross-sectional view taken in the CC direction of Fig. 9.

[0043] FIG. 12 is a perspective view showing a form in which an upper pack case and a lower pack case are assembled in a battery pack according to one embodiment of the present invention.

[0044] FIG. 13 is an exploded perspective view showing the lower pack case and cell module assembly in a battery pack according to one embodiment of the present invention from a downward direction.

[0045] Figure 14 is an exploded perspective view showing the area where the strap of the cell module assembly illustrated in Figure 13 is placed in the lower pack case.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] Furthermore, when we say that a layer, membrane, region, plate, or other part is "on" or "over" another part, this includes not only cases where it is "directly on" the other part, but also cases where there are other parts in between. Conversely, when we say that a part is "directly on" another part, it means that there are no other parts in between. Furthermore, saying that a part is "on" or "over" a reference part means that it is located above or below the reference part, and does not necessarily mean that it is located "above" or "over" the direction opposite to gravity.

[0050] 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.

[0051] 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.

[0052] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0053] Fig. 1 is a perspective view illustrating a battery pack according to one embodiment of the present invention. Fig. 2 is an exploded perspective view of the battery pack of Fig. 1. Fig. 3 is a perspective view illustrating a cell module assembly of the battery pack of Fig. 2.

[0054] The battery pack (10) includes a pack case (100), a cell module assembly (200), an insulating sheet (300), and a power unit (400), and the cell module assembly (200) and the power unit (400) are housed inside the pack case (100).

[0055] The pack case (100) includes an upper pack case (110), a lower pack case (130), a fixing member (150) that fixes the upper pack case (110) and the lower pack case (130) to each other, and a front cover (160). The lower pack case (130) and the upper pack case (110) are combined to surround the outside of the cell module assembly (200). For example, the upper pack case (110) may have a basically U-shaped frame shape with a closed rear end. For example, the lower pack case (130) may have a generally flat plate shape. The cell module assembly (200) may be mounted on the lower pack case (130) having a flat plate shape, and the upper pack case (110) may cover the cell module assembly (200).

[0056] However, the present invention is not limited to the above-described, and may be changed and modified in various ways, such as the lower pack case (130) and the upper pack case (110) may each be an L-shaped frame or a roll press type mono frame.

[0057] In addition, the front cover (160) is a member placed on the front of the cell module assembly (200). Hereinafter, based on the direction parallel to the direction in which the battery cells (210) of the cell module assembly (200) are stacked, one side on which the electric unit (400) including the BMS, etc. is mounted is referred to as the front, and the other side is referred to as the rear.

[0058] Meanwhile, a detailed description of the fixed member (150) will be provided later.

[0059] The cell module assembly (200) includes a battery cell stack, an end plate (220), and a busbar housing assembly (230). Additionally, a blocking member (240) may be included. The battery cell stack may be formed by stacking a plurality of battery cells (210).

[0060] A pair of end plates (220) are provided on each of the two side ends of the battery cell stack, i.e., the outermost part of the battery cell stack. The end plates (220) are arranged parallel to the battery cells (210). In addition, a pair of busbar housing assemblies (230) are arranged on the surface of each battery cell (210) of the battery cell stack facing the electrode leads (211). In the example of FIG. 3, a pair of busbar housing assemblies (230) are arranged on each of the two side ends of a plurality of battery cell stacks. Each of the busbar housing assemblies (230) is arranged in a direction perpendicular to the longitudinal direction of the battery cells (210). In addition, a pair of end plates (220) are arranged on the front and rear sides of the battery cell stack, respectively. Each end between the pair of busbar housing assemblies (230) is connected by a pair of end plates (220).

[0061] The end plate (220) may be made of, for example, a metal material, such as aluminum, iron, or stainless steel. The busbar housing assembly (230) includes a busbar housing (231) in which a busbar electrode (232) and an ICB (Inter Connector Board, 233) are arranged, and the busbar housing (231) may be made of, for example, a plastic material, and may be manufactured by plastic injection molding.

[0062] A busbar electrode (232) is arranged on the outer surface of the busbar housing (231), and includes a plurality of openings near the positions where the busbar electrode (232) is arranged. The electrode leads (211) of the battery cells (210) pass through the openings of the busbar housing assembly (230) and are coupled to the busbar electrodes (232). For reference, in the drawing of the present invention, the electrode leads (211) of each of the neighboring battery cells (210) pass through the openings formed in the busbar housing (231) and are coupled to each other, and the busbar electrodes (232) are coupled thereon.

[0063] Additionally, an ICB (233) is arranged on the outer surface of the busbar housing (231). In an embodiment of the present invention, the ICB (233) is arranged on the upper portion of the busbar electrode (232).

[0064] The ICB (233) transmits sensing data between the battery cell (210) and the BMS of the electric unit (400). The ICB (233) is a substrate having at least one element for transmitting sensing data, and may include a printed circuit board (PCB) having a circuit pattern formed on an insulating layer and a sensing cable connector to which a sensing cable is connected. The ICB (233) senses current and / or voltage in the battery cell (210) and transmits the sensed data to the BMS through the sensing cable. In addition, the BMS transmits data for maintaining and managing the battery cell (210) to the ICB (233) through the sensing cable, and ultimately controls the battery cell (210) electrically connected to the ICB (233). In detail, data regarding current and / or voltage in the battery cell (210) is transmitted to the printed circuit board of the ICB (233) via the bus bar electrode (232) coupled to the electrode lead (211) of the battery cell (210).

[0065] Meanwhile, the above-described embodiment has been described as an example in which electrode leads (211) are provided on both sides of the battery cell (210) and a pair of busbar housing assemblies (230) are provided on both ends of the battery cell stack, but the present invention is not limited to the above. It is also applicable to a case in which both electrode leads (211) are provided on one side of the battery cell (210) and the busbar housing assembly (230) is placed on one end of the battery cell stack, i.e., on the end toward which the electrode leads (211) face.

[0066] The blocking member (240) is arranged in contact with a large area of ​​the battery cell (210), and is arranged between neighboring battery cells (210) and / or between the outermost battery cell (210) of the battery cell stack and the end plate (220). The blocking member (240) can prevent thermal runaway between cells by blocking flames or sparks emitted from a battery cell (210) where a thermal event has occurred in the battery cell (210) from spreading to adjacent battery cells (210). The blocking member (240) may be arranged between a plurality of battery cells (210), and FIG. 3 illustrates, as an example, a case where the blocking member (240) is arranged every six battery cells (210). However, the embodiments of the present invention are not limited to what is illustrated, and various modifications and changes are possible.

[0067] The blocking member (240) has a roughly plate-like shape. The blocking member (240) includes a support plate and a swelling pad. The blocking member (240) may be included in multiple pieces depending on the number of battery cells (210). In addition, as described above, the blocking member (240) may be stacked together with the battery cells (210) to form a cell module assembly (200).

[0068] The support plate may be made of, for example, metal, plastic, or a combination thereof. The metal may be made of, for example, aluminum, iron, stainless steel, or a combination thereof. The plastic may also be made of, for example, a high-strength plastic such as reinforced plastic.

[0069] The outermost surface of the blocking member (240) includes a pair of swelling pads. The swelling pads may be made of silicone, plastic, or a combination thereof. If made of plastic, they may be made of, for example, a soft plastic, such as polyurethane foam (PU foam). The swelling pads may act as a buffer when the battery cell (210) swells.

[0070] Meanwhile, the cell module assembly (200) may include at least one strap (250), which will be described in detail later.

[0071] An insulating sheet (300) is placed between the cell module assembly (200) and the upper pack case (110) and has electrical insulation properties. The insulating sheet (300) may be, for example, a film made of PC (polycarbonate), PET, PP, or a combination thereof. Meanwhile, although not shown in FIG. 2, an insulating sheet may also be provided between the cell module assembly (200) and the lower pack case (130).

[0072] The electric unit (400) is disposed on one side of the cell module assembly (200) (i.e., the front of the cell module assembly (200)). In the example of FIG. 2, the electric unit (400) is disposed on the outer surface of the end plate (220) disposed on the front of the cell module assembly (200). The electric unit (400) may include a BMS, an electric unit housing that accommodates each component (e.g., a BMS, a power cable, etc.), and a power cable. The BMS includes a connector terminal so as to be electrically connected to the sensing cable. The electric unit (400) may also include various components for controlling or managing charging or discharging of the battery pack, such as a relay, a fuse, and a current sensor. Since each component of the electric unit (400) may be implemented by employing an electric unit equipped in a typical battery pack, a more detailed description of the electric unit (400) will be omitted.

[0073] FIG. 4 is a perspective view showing only the upper pack case and the lower pack case in the battery pack of FIG. 2.

[0074] Referring to FIG. 4, the upper pack case (110) may include a top plate (111) that covers the upper surface of the cell module assembly (200) and side plates (112) that extend downward from the edge of the top plate (111) to cover both side surfaces and the rear surface of the cell module assembly (200). The front of the upper pack case (110) may be open. The lower pack case (130) may include a bottom plate (131) that supports the lower portion of the cell module assembly (200) and a fixing plate (132) that extends upward from the edge of the bottom plate (131).

[0075] The upper pack case (110) is coupled with the lower pack case (130) to form a storage space in which the cell module assembly (200) is stored. More specifically, the side plate (112) of the upper pack case (110) and the fixing plate (132) of the lower pack case (130) can be coupled to each other, and for this purpose, an upper fixing part (120) can be formed on the side plate (112) of the upper pack case (110), and a lower fixing part (140) can be formed on the fixing plate (132) of the lower pack case (130). When the upper pack case (110) and the lower pack case (130) are assembled, the upper fixing part (120) can overlap at least a portion of the lower fixing part (140), and the upper fixing part (120) and the lower fixing part (140) can be fixed to each other.

[0076] At this time, the description that the upper fixing part (120) and the lower fixing part (140) can overlap each other means that at least a portion of the surface of the upper fixing part (120) and at least a portion of the surface of the lower fixing part (140) are combined in a laminated form while in contact with each other. Hereinafter, the detailed configuration of the upper fixing part (120) and the lower fixing part (140) will be described with reference to the drawings.

[0077] Fig. 5 is an enlarged perspective view of part A of Fig. 4. Fig. 6 is an enlarged view of part A of Fig. 4 from the side. Fig. 7 is an enlarged view of part A of Fig. 4 from the bottom. Fig. 8 is an enlarged perspective view of part B of Fig. 4. Fig. 9 is an external perspective view showing the part where the upper pack case and the lower pack case are joined. Fig. 10 is an internal perspective view showing the part where the upper pack case and the lower pack case are joined. Fig. 11 is a cross-sectional view taken along the CC direction of Fig. 9.

[0078] First, referring to FIGS. 5 to 7, 9 and 10, the upper fixing portion (120) may include a first upper overlapping portion (121), a second upper overlapping portion (123), a connecting portion (124), an upper cut portion (125) and a guide portion (126).

[0079] The upper pack case (110) and the lower pack case (130) can be assembled so that one of the inner and outer surfaces of the first upper overlapping portion (121) overlaps with each other on the inner surface of the first lower overlapping portion (141), and the other of the inner and outer surfaces of the second upper overlapping portion (123) overlaps with each other on the outer surface of the second lower overlapping portion (142).

[0080] Specifically, the first upper overlapping portion (121) is formed by being recessed inwardly from the upper pack case (110) and is a flat portion so as to overlap with the lower fixing portion (140) on the outer surface of the lower fixing portion (140). An inclined surface (122) that is inclined inwardly from the upper pack case (110) is formed at the connection portion between the first upper overlapping portion (121) and the upper pack case (110). Since the first upper overlapping portion (121) recessed inwardly from the upper pack case (110) comes into contact with the outer surface of the lower fixing portion (140) formed in the lower pack case (130), at least a portion of the upper pack case (110) can be spaced apart from the lower pack case (130) by a predetermined distance.

[0081] The space formed by separating the upper pack case (110) and the lower pack case (130) by a predetermined distance can function as a ventilation hole through which air circulates. Accordingly, heat generated from the battery cells (210) of the cell module assembly (200) housed inside the pack case (100) can be cooled by air flowing into the interior of the pack case (100) through the separation space, and air that has absorbed heat inside the pack case (100) can be discharged to the outside through the separation space.

[0082] The second upper overlapping portion (123) is formed by being recessed inward from the first upper overlapping portion (121), and is a flat portion so as to overlap with the lower fixing portion (140) on the inner surface of the lower fixing portion (140). A connecting portion (124) and an upper cut portion (125) are formed at the connecting portion between the first upper overlapping portion (121) and the second upper overlapping portion (123). First, the upper cut portion (125) is a portion formed by cutting a portion of the connecting portion between the first upper overlapping portion (121) and the second upper overlapping portion (123) upward. The connecting portion (124) is a portion formed in the remainder of the connecting portion between the first upper overlapping portion (121) and the second upper overlapping portion (123). The connecting portion (124) connects the first upper overlapping portion (121) and the second upper overlapping portion (123), and is inclined inward from the first upper overlapping portion (121). As illustrated in FIGS. 9 and 10, when the upper pack case (110) and the lower pack case (130) are assembled, a lower fixing part (140) can be inserted into the upper cut-out part (125). Meanwhile, a more detailed description regarding the combination of the upper fixing part (120) and the lower fixing part (140) will be provided later.

[0083] The guide portion (126) is formed at the end portion of the second upper overlapping portion (123) toward the lower pack case (130). The guide portion (126) is inclined inward from the second upper overlapping portion (123). When the upper pack case (110) and the lower pack case (130) are assembled, the lower fixing portion (140) can move along the guide portion (126) to the outer surface of the second upper overlapping portion (123). That is, the guide portion (126) can guide the lower fixing portion (140) so that the second upper overlapping portion (123) can overlap with the lower fixing portion (140) on the inner surface of the lower fixing portion (140).

[0084] Meanwhile, the above-described inner direction refers to the direction from the pack case (100) toward the inner space where the cell module assembly (200) is stored, and the outer direction refers to the direction from the pack case (100) toward the outside. In addition, the inner surface and the outer surface refer to the surface facing the inner space and the surface facing the outside, respectively, of a certain member.

[0085] Referring to FIGS. 8 to 10, the lower fixing portion (140) includes a first lower overlapping portion (141), a second lower overlapping portion (142), and a lower cut portion (143) formed by cutting downward between the first lower overlapping portion (141) and the second lower overlapping portion (142).

[0086] When assembling the upper pack case (110) and the lower pack case (130), the first lower overlapping portion (141) overlaps with the first upper overlapping portion (121), and the second lower overlapping portion (142) overlaps with the second upper overlapping portion (123). More specifically, the outer surface of the first lower overlapping portion (141) and the inner surface of the first upper overlapping portion (121) overlap with each other, and the inner surface of the second lower overlapping portion (142) and the outer surface of the second upper overlapping portion (123) overlap with each other.

[0087] Referring to FIGS. 9 to 11, when the upper pack case (110) and the lower pack case (130) are assembled, the upper cutout (125) and the lower cutout (143) are inserted into each other. Accordingly, the upper fixing part (120) can intersect the lower fixing part (140) at the lower cutout (143). More specifically, when the upper cutout (125) and the lower cutout (143) are inserted into each other, the upper fixing part (120) can intersect the lower fixing part (140) at the lower cutout (143). In addition, the lower fixing part (140) can intersect the upper fixing part (120) at the lower cutout (143).

[0088] The upper fixing portion (120) forms an inclined surface (122) at the connection portion between the first upper overlapping portion (121) and the second upper overlapping portion (123). The inclined surface (122) intersects the lower fixing portion (140) at the lower cut portion (143). Therefore, in order for the first upper overlapping portion (121) and the second upper overlapping portion (123) to stably overlap with the first lower overlapping portion (141) and the second lower overlapping portion (142), respectively, the width (W2) of the lower cut portion (143) may be greater than or equal to the width (W1) of the connection portion between the first upper overlapping portion (121) and the second upper overlapping portion (123). At this time, the width (W2) of the lower cut portion (143) described above and the width (W1) of the connection portion between the second upper overlapping portion (123) mean the length in the direction parallel to the stacking direction of the battery cell (210) when viewed from the side direction of the cell module assembly (200).

[0089] The fixing member (150) can fix the upper pack case (110) and the lower pack case (130) to each other by penetrating the portion where the upper fixing part (120) and the lower fixing part (140) overlap each other. Specifically, the upper fixing part (120) includes an upper through hole (127) formed in the second upper overlapping part (123), and the lower fixing part (140) includes a lower through hole (144) formed in the second lower overlapping part (142). When the first upper overlapping portion (121) and the second upper overlapping portion (123) of the upper fixing portion (120) and the first lower overlapping portion (141) and the second lower overlapping portion (142) of the lower fixing portion (140) overlap each other, the upper through hole (127) and the lower through hole (144) are aligned with each other, and the fixing member (150) passes through the upper through hole (127) and the lower through hole (144) to fix the upper fixing portion (120) and the lower fixing portion (140).

[0090] The fixing member (150) may include a bolt (151) penetrating the upper through hole (127) and the lower through hole (144) and a nut (152) fastened to the bolt (151). However, the type of the fixing member (150) is not limited to what has been described above, and any fixing means capable of fixing the overlapping portions of the upper fixing portion (120) and the lower fixing portion (140) may be changed and modified in various ways.

[0091] According to embodiments of the present invention, the upper fixing part (120) can be fixed by the fixing member (150) at the overlapping portion of the upper fixing part (120) and the lower fixing part (140) while being intersected with each other with respect to the lower fixing part (140), so that the fixing points can be reduced compared to a general fixing method in which the upper pack case and the lower pack case are fixed only by the fixing member.

[0092] In addition, since the upper fixing part (120) includes a first upper overlapping part (121) and a second upper overlapping part (123) that are sunken inward, even if a component tolerance occurs, the assembly tolerance can be minimized when assembling the upper pack case (110) and the lower pack case (130). That is, the upper pack case (110) and the lower pack case (130) can be made of a material that has rigidity but is elastically deformable, and as illustrated in FIG. 11, there is a space spaced apart by a predetermined distance between the upper pack case (110) and the lower pack case (130), so even if a component tolerance occurs, the upper pack case (110) and the lower pack case (130) can be elastically deformed to some extent, thereby reducing the assembly tolerance.

[0093] In addition, since the assembly of the upper fixing part (120) can be guided through the guide part (126) formed in the second upper overlapping part (123) of the upper fixing part (120), even if a component tolerance occurs in the upper pack case (110), the assembly of the upper pack case (110) and the lower pack case (130) can be easy.

[0094] Meanwhile, since the first upper overlapping portion (121) and the second upper overlapping portion (123) of the upper fixing portion (120) are formed by being sunken inward, the inner surface of the first upper overlapping portion (121) overlaps with the outer surface of the first lower overlapping portion (141), and the outer surface of the second upper overlapping portion (123) overlaps with the inner surface of the second lower overlapping portion (142), but is not limited by the above. For example, the first upper overlapping portion (121) and the second upper overlapping portion (123) of the upper fixing portion (120) may be formed by being protruded outward. Alternatively, the first upper overlapping portion (121) of the upper fixing portion (120) may be sunken inward, and the second upper overlapping portion (123) may be formed by being protruded outward.

[0095] FIG. 12 is a perspective view showing a form in which an upper pack case and a lower pack case are assembled in a battery pack according to one embodiment of the present invention.

[0096] Referring to Fig. 12, an insulating sheet (300) is placed between the cell module assembly (200) and the upper pack case (110). The upper pack case (110) is coupled to the lower pack case (130) while the cell module assembly (200) is covered by the insulating sheet (300). Referring again to Fig. 2, a power unit (400) is mounted on the front of the cell module assembly (200), and various components for connecting the cell module assembly (200) and the power unit (400) may be placed. For example, a sensing cable may be placed to extend along the side of the cell module assembly (200). If the upper pack case (110) and the lower pack case (130) are combined while the cell module assembly (200) is not covered by the insulating sheet (300), interference may occur, such as the external parts of the cell module assembly (200), especially the parts arranged on the side of the cell module assembly (200), being caught by the upper fixing part (120) formed inwardly from the upper pack case (110), and thus damage to the parts may occur.

[0097] Accordingly, the insulating sheet (300) can cover the upper part, both sides, and the rear part of the cell module assembly (200) so that interference does not occur between the upper fixing part (120) of the upper pack case (110) and the cell module assembly (200) when the upper pack case (110) and the lower pack case (130) are assembled, and the upper pack case (110) can be coupled to the lower pack case (130) while the cell module assembly (200) is covered by the insulating sheet (300).

[0098] Fig. 13 is an exploded perspective view showing the lower pack case and the cell module assembly in a battery pack according to one embodiment of the present invention from a downward direction. Fig. 14 is an exploded perspective view showing an area where the strap of the cell module assembly illustrated in Fig. 13 is placed on the lower pack case.

[0099] Referring to FIGS. 13 and 14, the cell module assembly (200) includes a pair of end plates (220) disposed at opposite side ends of the battery cell stack and at least one strap (250) connecting the pair of end plates (220). The at least one strap (250) can connect the pair of end plates (220) at each of the upper side and the lower side of the cell module assembly (200). The at least one strap (250) can strengthen the bonding of the cell module assembly (200) by connecting the pair of end plates (220). More specifically, the at least one strap (250) strengthens the bonding of the pair of end plates (220) and the plurality of battery cell stacks disposed therebetween. Accordingly, the alignment of the plurality of battery cell stacks can be prevented from being misaligned by the at least one strap (250).

[0100] The lower pack case (130) includes a drainage hole (133) for discharging moisture in the internal space of the pack case (100) to the outside of the pack case (100). The drainage hole (133) may be a passage formed by penetrating the bottom plate (131) of the lower pack case (130). At least one drainage hole (133) may be provided, and preferably, a plurality of drainage holes may be provided to facilitate the discharge of moisture.

[0101] The drain hole (133) may be formed in a first area (A1) corresponding to a portion where at least one strap (250) connected to the cell module assembly (200) is disposed when the cell module assembly (200) is mounted on the lower pack case (130). When a plurality of drain holes (133) are formed, the plurality of drain holes (133) may be arranged along the extension direction of at least one strap (250) in the first area (A1). Since the drain hole (133) is formed in the first area (A1) corresponding to a portion where at least one strap (250) is disposed, the cell module assembly (200) can be prevented from being directly exposed to the outside. Accordingly, the cell module assembly (200) can be prevented from coming into direct contact with external foreign substances through the drain hole (133).

[0102] The lower pack case (130) includes a plurality of protrusions (134) for spacing out the cell module assembly (200) and the drain hole (133). Since the drain hole (133) is formed corresponding to a portion where at least one strap (250) of the cell module assembly (200) is disposed, if the bottom plate (131) of the lower pack case (130) and the cell module assembly (200) are not spaced out, the drain hole (133) may be blocked by the strap (250) of the cell module assembly (200). If the drain hole (133) is blocked by the strap (250), a problem may arise in which moisture inside the pack case (100) is difficult to discharge.

[0103] To prevent such a problem, a plurality of protrusions (134) may be formed in the lower pack case (130). In addition, in order to facilitate drainage through the drain hole (133), the plurality of protrusions (134) may be formed in a second area (A2) other than the first area (A1) in the lower pack case (130). That is, since a protruding portion is not formed on the first area (A1) where the drain hole (133) is formed in the lower pack case (130), a drainage path through which moisture is discharged can be formed.

[0104] In addition, an energy storage system (ESS) according to one embodiment of the present invention includes one or more battery packs (10) according to the embodiments of the present invention described above. In addition, an energy storage device according to one embodiment of the present invention may further include general components included in energy storage devices in addition to the battery pack (10).

[0105] 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.

[0106] [Explanation of symbols]

[0107] 10: Battery pack

[0108] 100: Pack Case

[0109] 110: Upper pack case

[0110] 120: Upper fixing part

[0111] 130: Lower pack case

[0112] 140: Lower fixing part

[0113] 150: Fixed member

[0114] 160: Front cover

[0115] 200: Cell module assembly

[0116] 210: Battery cell

[0117] 220: End Plate

[0118] 230: Busbar housing assembly

[0119] 231: Busbar housing

[0120] 232: Busbar electrode

[0121] 233: Inter Connector Board (ICB)

[0122] 240: Absence of blocking

[0123] 250: Strap

[0124] 300: Insulating sheet

[0125] 400: Battlefield Unit

Claims

1. A cell module assembly including a battery cell stack in which a plurality of battery cells are stacked; A lower pack case including a bottom plate supporting the lower portion of the cell module assembly and a fixing plate extending upward from a rim of the bottom plate; An upper pack case covering the upper surface, both sides and the rear surface of the cell module assembly and coupled with the lower pack case; A lower fixing part formed on the fixing plate of the lower pack case; and A battery pack comprising an upper fixing portion formed in the upper pack case and fixed to each other by overlapping at least a portion of the lower fixing portion when the lower pack case and the upper pack case are assembled.

2. In paragraph 1, The upper fixed part above, A first upper overlapping portion overlapping the lower fixing portion on one of the inner and outer surfaces of the lower fixing portion; and A battery pack comprising a second upper overlapping portion overlapping the lower fixing portion on the other side of the inner and outer surfaces of the lower fixing portion.

3. In paragraph 2, A battery pack, wherein the second upper overlapping portion is formed by recessing inwardly from the first upper overlapping portion.

4. In paragraph 3, The above first upper overlapping portion is formed by recessing inwardly from the upper pack case, A battery pack, wherein at least a portion of the upper pack case is spaced apart from the lower pack case by a predetermined distance.

5. In paragraph 4, A battery pack, wherein the inner surface of the first upper overlapping portion overlaps with the outer surface of the lower fixing portion, and the outer surface of the second upper overlapping portion overlaps with the inner surface of the lower fixing portion.

6. In paragraph 3, The upper fixing portion is formed by cutting a portion of the connection portion between the first upper overlapping portion and the second upper overlapping portion upward; and Further comprising a connecting portion formed in the remaining portion of the connecting portion to connect the first upper overlapping portion and the second upper overlapping portion; A battery pack, wherein the lower fixing part is inserted into the upper cut-out when the lower pack case and the upper pack case are assembled.

7. In paragraph 6, The lower fixed portion includes a lower cut portion formed by cutting downward, A battery pack, wherein when the lower pack case and the upper pack case are assembled, the upper cut-out and the lower cut-out are inserted into each other.

8. In paragraph 7, A battery pack, wherein the upper fixing portion intersects the lower fixing portion at the lower cut portion.

9. In paragraph 7, A battery pack wherein the lower fixing portion intersects the upper fixing portion at the upper cut portion.

10. In paragraph 7, A battery pack wherein the width of the lower cut portion is greater than or equal to the width of the connecting portion between the first upper overlapping portion and the second upper overlapping portion.

11. In paragraph 3, A battery pack, wherein the upper fixing portion is formed at an end portion facing the lower pack case from the second upper overlapping portion, and further includes a guide portion inclined inwardly.

12. In paragraph 1, A battery pack further comprising a fixing member that penetrates a portion where the lower fixing member and the upper fixing member overlap each other and fixes the lower pack case and the upper pack case to each other.

13. In paragraph 1, Further comprising an insulating sheet disposed between the cell module assembly and the upper pack case; A battery pack, wherein the upper pack case is coupled to the lower pack case while the cell module assembly is covered by the insulating sheet.

14. In paragraph 13, A battery pack in which the insulating sheet covers the upper part, both sides, and the rear surface of the cell module assembly so that interference does not occur between the upper pack case and the cell module assembly when the lower pack case and the upper pack case are assembled.

15. In paragraph 1, The above cell module assembly comprises a pair of end plates arranged on both sides of the battery cell stack; and further comprising at least one strap connecting between said pair of end plates; A battery pack, wherein the lower pack case includes a drain hole formed in a first area corresponding to a portion where the at least one strap is placed.

16. In paragraph 15, A battery pack, wherein the drain hole includes a plurality of drain holes arranged along the extension direction of the at least one strap.

17. In paragraph 16, A battery pack, wherein the lower pack case further includes a plurality of protrusions for spacing between the cell module assembly and the drain hole.

18. In paragraph 17, A battery pack, wherein the plurality of protrusions are formed in a second region other than the first region in the lower pack case.

19. An energy storage device comprising a battery pack according to any one of claims 1 to 18.

Images