Battery pack

Abstract

The disclosed battery pack comprises: a cell unit including a plurality of battery cells; a base plate for supporting the bottom surface of the cell unit; a cell unit fixing agent which is interposed between the cell unit and the base plate, and which includes a structural adhesive that is applied to or comes in contact with a portion of the bottom surface of the cell unit and a non-curable filler that is applied to or comes in contact with the remaining portion thereof; and a cell lower panel, which is interposed between the base plate and the cell unit fixing agent, is detachably fastened to the base plate, and is adhered and fixed to the cell unit by means of the structural adhesive.

Description

battery pack

[0001] The present invention relates to a battery pack, and more particularly, to a battery pack suitable for extending the lifespan with minimal maintenance and repair without having to discard the entire battery pack by enabling replacement of a battery cell among a plurality of battery cells mounted in the battery pack when a problem occurs in the battery cell.

[0002] This application claims the benefit of priority from Republic of Korea Patent Application No. 10-2023-0094962, filed July 21, 2023, the entire contents of which are incorporated herein by reference.

[0003] To improve space utilization in battery packs, a cell-to-pack (CTP) structure has been proposed. This structure offers the advantage of improving space utilization by allowing multiple battery cells to be assembled directly into the pack without modularization.

[0004] In cell-to-pack designs, separate module housings are omitted or simplified, leading to new structures for efficiently mounting multiple battery cells within the pack case. For example, a cell unit (equivalent to a conventional battery module), where multiple battery cells form a single group, can be designed with a side frame attached, and the side frame of the cell unit can be secured to the cross beam of the pack case.

[0005] Alternatively, the side frames of adjacent cell units may be overlapped vertically and fixed to the base plate to replace the role of the pack cross beam (a cross beam provided in the pack case). In addition, by interposing thermal resin between the bottom surface of the cell unit where the battery cells are exposed and the base plate of the pack case, the conductive heat dissipation of the cell unit can be promoted, and the cell unit can be fixed more firmly through the curing of the thermal resin.

[0006] However, the structure of the battery pack that omits the configuration of the pack cross beam by utilizing the side frame of the cell unit and further fixes the cell unit through curing of thermal resin has many advantages in terms of the cell-to-pack structure that improves the space utilization of the battery pack by directly assembling multiple battery cells into the battery pack without a modular structure, but has disadvantages in terms of battery pack maintenance. In other words, this cell-to-pack structure makes it very difficult to disassemble the assembled battery pack into cell units.

[0007] For example, a cell-to-pack structure, in which the side frames of adjacent cell units overlap each other and are fixed to a base plate, requires that the cell units be removed one by one in the reverse order of assembly for disassembly. Furthermore, a structure that fixes the bottom of the cell unit through the curing of thermal resin can cause damage to the battery cells bonded to the thermal resin when the cell unit is removed, which can lead to extremely dangerous consequences such as electrolyte leakage.

[0008] There is a high need for the development of a cell-to-pack structured battery pack that can be easily disassembled down to the battery cell unit, thereby enabling maintenance and repair of the battery pack by replacing the battery cell even if a problem occurs in only one of the battery cells within the battery pack, thereby enabling the use of the expensive battery pack until its designed lifespan without having to discard it.

[0009] The purpose of the present invention is to provide a battery pack having a cell-to-pack structure, in which any cell unit can be easily removed regardless of the assembly order, thereby facilitating replacement of a battery cell in which a problem has occurred.

[0010] However, the technical problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0011] The present invention relates to a battery pack, and in one example, includes a cell unit including a plurality of battery cells, a base plate supporting a bottom surface of the cell unit, a cell unit fixing agent interposed between the cell unit and the base plate, the cell unit fixing agent including a structural adhesive applied to or in contact with a portion of the bottom surface of the cell unit and a non-curing filler applied to or in contact with the remaining portion, and a cell lower panel interposed between the base plate and the cell unit fixing agent, detachably fastened to the base plate, and adhesively fixed to the cell unit by the structural adhesive.

[0012] In one embodiment of the present invention, the structural adhesive may not invade an area outside the cell lower panel.

[0013] And, the cell lower panel includes a body in which the structural adhesive is interposed, and a stud bolt extending from the body, and the stud bolt can pass through a through hole formed in the base plate and be fixed with a nut.

[0014] The upper surface of the base plate may be provided with a concave surface including the through hole, and the body of the cell lower panel may be accommodated within the concave surface.

[0015] And, the upper surface of the body accommodated in the concave surface can be aligned with the upper surface of the base plate.

[0016] The bottom surface of the above base plate may be provided with a recess that allows the connection of the tool while accommodating the nut so that it does not protrude outward.

[0017] According to an embodiment of the present invention, a cooling plate may be coupled to the lower surface of the base plate, in which case the stud bolt and nut are located in an area of ​​the cooling plate where a flow path is not formed.

[0018] And, the structural adhesive forms a curable adhesive layer, and the non-curable filler forms a non-curable adhesive layer.

[0019] Accordingly, the cell unit is released from its fixation to the base plate by releasing the nut fastening of the stud bolt, and can be pulled out of the pack together with the cell lower panel that is mutually bonded by the structural adhesive.

[0020] The above cell unit fixing agent may have the non-curing filler placed on both sides of the structural adhesive.

[0021] The battery pack of the present invention having the above configuration firmly fixes the cell unit to the base plate via the cell lower panel using a structural adhesive that forms a semi-permanent adhesive surface, but the cell lower panel is in a state where it can be separated from the base plate, so that the structural adhesive does not interfere with the removal of the cell unit. Consequently, even if a firm, curable adhesive layer is formed by the structural adhesive on a portion of the lower surface of the cell unit to firmly fix the cell unit to the base plate, the battery pack of the present invention facilitates the removal of the cell unit via the cell lower panel.

[0022] In addition, the battery pack of the present invention has the side frames of the cell units bolted to the upper surface of the cross beam to secure the cell units laterally, and the side frames of adjacent cell units do not overlap each other on the cross beam. Accordingly, when separating a defective cell unit, there is no need to first separate other surrounding cell units, making removal easy.

[0023] However, the technical effects that can be obtained through the present invention are not limited to the above-described effects, and other effects that are not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0024] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0025] FIG. 1 is a drawing showing a fixing structure of a cell unit in a battery pack according to the present invention.

[0026] Figure 2 is a cross-sectional view taken along line “AA” of Figure 1.

[0027] Figure 3 is a drawing showing a state in which the cell unit of Figure 2 is separated from the battery pack.

[0028] Figure 4 is a drawing showing the cell lower panel.

[0029] Figure 5 is a drawing showing the bottom of the battery pack.

[0030] Fig. 6 is a drawing illustrating an embodiment in which a cooling plate is provided in a battery pack.

[0031] Figures 7 and 8 are drawings illustrating the assembly process of a battery pack according to the present invention.

[0032] The present invention can be modified in various ways and has many embodiments, and specific embodiments will be described in detail below.

[0033] However, this is not intended to limit the present invention to a specific embodiment, but should be understood to include all modifications, equivalents, or substitutes included in the spirit and technical scope of the present invention.

[0034] In the present invention, it should be understood that terms such as “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0035] Additionally, in the present invention, when a part such as a layer, film, region, or plate is described as being "on" another part, this includes not only cases where it is "directly above" the other part, but also cases where there is another part in between. Conversely, when a part such as a layer, film, region, or plate is described as being "under" another part, this includes not only cases where it is "directly below" the other part, but also cases where there is another part in between. Furthermore, in the present application, "being placed on" may include cases where it is placed below as well as above.

[0036]

[0037] The present invention relates to a battery pack, and in one example, includes a cell unit including a plurality of battery cells, a base plate supporting a bottom surface of the cell unit, a cell unit fixing agent interposed between the cell unit and the base plate, the cell unit fixing agent including a structural adhesive applied to or in contact with a portion of the bottom surface of the cell unit and a non-curing filler applied to or in contact with the remaining portion, and a cell lower panel interposed between the base plate and the cell unit fixing agent, detachably fastened to the base plate, and adhesively fixed to the cell unit by the structural adhesive.

[0038] The structural adhesive forms a curable adhesive layer, and the non-curable filler forms a non-curable adhesive layer, whereby the cell lower panel, which is released from its fixed state with respect to the base plate, can be pulled out of the pack together with the cell units that are mutually bonded by the structural adhesive.

[0039] The battery pack of the present invention having the above configuration is characterized in that the adhesive force for fixing the cell unit to the base plate is provided by both the structural adhesive and the non-curable filler, wherein the curable structural adhesive is locally adhered to the bottom surface of the cell unit, but the structural adhesive is interposed in the cell lower panel that is separable from the base plate, so that the cell unit and the cell lower panel with the structural adhesive interposed therebetween are pulled out of the pack together.

[0040] That is, by limiting the area where the curable structural adhesive intervenes to the cell lower panel, it becomes easier to separate the defective cell unit from the battery pack, thereby enabling the entire battery pack to be reused without having to discard it by replacing only the defective cell unit.

[0041] Hereinafter, a specific embodiment of a battery pack (10) according to the present invention will be described in detail with reference to the attached drawings. For reference, the directions of front / back, up / down / left / right, etc., used to designate relative positions in the following description are intended to aid understanding of the invention, and unless otherwise specified, the directions depicted in the drawings are taken as a reference.

[0042]

[0043] [First Embodiment]

[0044] FIG. 1 is a drawing showing a fixing structure of a cell unit (200) in a battery pack (10) according to the present invention, and FIG. 2 is a cross-sectional view taken along the line “AA” of FIG. 1.

[0045] The present invention relates to a battery pack (10), which includes a pack case (100) and a plurality of cell units (200) mounted on the pack case (100). Here, the cell unit (200) refers to a unit in which a plurality of battery cells (210) are grouped together, and includes a structure for forming the plurality of battery cells (210) into a unit. For example, the battery pack may include a bus bar frame assembly (220) that mechanically and electrically couples the plurality of battery cells (210) at both transverse ends from which leads (not shown) of the battery cells (210) protrude, and a side frame (230) that protects the battery cells (210) on both longitudinal sides. Accordingly, on the cell unit (200), the plurality of battery cells (210) are aligned in a row along the thickness direction in an upright position. And, the illustrated cell unit (200) is suitable for a battery pack (10) of a cell-to-pack structure, so that the bottom surface is exposed with the battery cell (210) as is without a separate structure.

[0046] The pack case (100) includes a base plate (110), which is a bottom plate. The base plate (110) supports the bottom surface of the cell unit (200), i.e., the bottom surfaces of multiple battery cells (210), and absorbs heat in the form of heat conduction through the bottom surface of the cell unit (200) and dissipates it to the outside. In order to discharge the absorbed heat to the outside through a refrigerant, a heat sink may be built into the base plate (110) itself, or a separate cooling plate (150) may be bonded to the bottom surface thereof.

[0047] In addition, the pack case (100) may include a side plate (120) that is coupled along the perimeter of the base plate (110) to form an accommodation space therein, and a cross beam (130) that is coupled to the base plate (110) to horizontally divide the accommodation space inside the base plate (110). Depending on the embodiment, as shown in the attached FIG. 1, the pack case (100) may further include a center beam (140) that vertically divides the accommodation space inside the base plate (110), and accordingly, the accommodation space of the pack case (100) may be arranged in a grid by the cross beam (130) and the center beam (140).

[0048] As one of the fixing structures for a plurality of cell units (200) mounted on a base plate (110), the structure includes a cell unit fixing agent (300) interposed between the cell units (200) and the base plate (110), and the cell unit fixing agent (300) is composed of two types: a structural adhesive (310) and a non-curing filler (320). The structural adhesive (310) and the non-curing filler (320) have in common that they have high thermal conductivity for smooth heat dissipation, but there is a distinct difference in adhesive strength and curing properties.

[0049] The structural adhesive (310) is a cell unit fixing agent (300) that forms a curable adhesive layer (312) between the base plate (110) and the cell unit (200). For example, a curable thermal resin can be applied as the structural adhesive (310). The thermal resin has the properties of a viscous gel in the initial stage of application, but hardens into a solid form after a certain period of time when exposed to air. As a result of the hardening of the thermal resin, the bottom surface of the cell unit (200) is firmly fixed onto the base plate (110).

[0050] On the other hand, the non-curing filler (320) is a cell unit fixing agent (300) that forms a non-curing adhesive layer (322) between the base plate (110) and the cell unit (200), and has a property of not curing for a long period of time, such as the lifespan or service warranty period of the battery pack (10), despite temperature fluctuations due to the passage of time and repeated charging and discharging. The non-curing filler (320) acts as an adhesive and a buffer, and the adhesive strength of the non-curing filler (320) is much weaker than that of the structural adhesive (310). Therefore, the non-curing filler (320) does not act as an obstacle in the process of separating the cell unit (200) from the base plate (110). As such a non-curable filler (320), for example, a gap filler under the trade name “TGF 3010 APS” from Henkel AG & Co. KGaA, headquartered in Düsseldorf, Germany, can be applied.

[0051] In addition, the battery pack (10) of the present invention includes a cell lower panel (400) that can ensure smooth separation of the cell unit (200) from the pack case (100). The cell lower panel (400) is interposed between the base plate (110) and the cell unit fixing agent (300). More specifically, the cell lower panel (400) is interposed between the base plate (110) and the structural adhesive (310). The cell lower panel (400) is detachably fastened to the base plate (110), and the structural adhesive (310) is adhered to the upper surface of the cell lower panel (400). Accordingly, the cell lower panel (400) is adhesively fixed to the cell unit (200) by the structural adhesive (310). On the other hand, the cell lower panel (400) can be fixed or detached from the base plate (110).

[0052] FIG. 3 is a drawing illustrating a state in which a cell unit (200) is separated from a battery pack (10). Before the cell unit (200) is housed in the pack case (100), the cell lower panel (400) is coupled and fixed to the base plate (110). The cell unit (200), as illustrated in FIG. 2, is bonded and fixed to the base plate (110) by a cell unit fixing agent (300). Among the cell unit fixing agents (300), a cured structural adhesive (310) semi-permanently fixes the cell unit (200), and a non-curing filler (320) bonded to the remaining area of ​​the bottom surface of the cell unit (200) fixes the cell unit (200) with an adhesive strength that allows the bonding surface to be separated when an appropriate force is applied.

[0053] In the fixed structure of the cell unit (200), as shown in FIG. 3, when the cell lower panel (400) is released from the base plate (110) and the cell unit (200) is removed upward, the cell lower panel (400) fixed by the structural adhesive (310) remains attached to the cell unit (200), while the non-curing filler (320) region with weak adhesive force separates from the adhesive surface. Accordingly, the cell unit (200) is pulled out of the pack case (100) with the cell lower panel (400) attached to its bottom surface.

[0054] In other words, the structural adhesive (310) forming a semi-permanent bonding surface firmly fixes the base plate (110) and the cell unit (200) via the cell lower panel (400), but since the cell lower panel (400) is in a state where it can be separated from the base plate (110), the curable adhesive layer (312) formed by the structural adhesive (310) does not interfere with the removal of the cell unit (200). In addition, the non-curable adhesive layer (322) formed by the non-curable filler (320) does not interfere with the removal of the cell unit (200) due to an appropriate traction force applied when the cell unit (200) is removed. As a result, even though a rigid curable adhesive layer (312) is formed on a portion of the lower surface of the cell unit (200) by the structural adhesive (310) so that the cell unit (200) is firmly fixed to the base plate (110), the battery pack (10) of the present invention facilitates the removal of the cell unit (200) by the cell lower panel (400).

[0055] For smooth separation of the cell unit (200), it is preferable that the structural adhesive (310) does not invade the area outside the cell lower panel (400). That is, it is advantageous for the detachment of the cell unit (200) if the structural adhesive (310) does not form a curable adhesive layer (312) between the base plate (110) and the cell unit (200) without the interposition of the cell lower panel (400). In addition, it may be preferable that the curable adhesive layer (312) and the non-curable adhesive layer (322) are evenly arranged so that a uniform adhesive force is applied to the cell unit (200). To this end, the cell unit fixing agent (300) may be configured such that the non-curable filler (320) is arranged on both sides of the structural adhesive (310) located at the center.

[0056] This cell unit fixing agent (300) may be applied to the base plate (110) and the cell lower panel (400) so that the lower surface of the cell unit (200) comes into contact with the cell unit fixing agent (300), or may be applied directly to the lower surface of the cell unit (200). However, since the standard for dividing the area of ​​the curable adhesive layer (312) and the non-curable adhesive layer (322) is the cell lower panel (400), it may be advantageous in terms of process management to apply the cell unit fixing agent (300) on the base plate (110) on which the cell lower panel (400) is installed.

[0057] Fig. 4 is a drawing illustrating a cell lower panel (400), and Fig. 5 is a drawing illustrating a bottom surface of a battery pack (10). In the illustrated embodiment, the cell lower panel (400) includes a body (410) in which a structural adhesive (310) is interposed, and a stud bolt (420) extending from the body (410). The stud bolt (420) extending downwardly of the cell lower panel (400) passes through a through hole (112) formed in a base plate (110) and is secured with a nut (430). If the base plate (110) incorporates a heat sink, i.e., if a flow path (not shown) for a coolant to flow is formed inside the base plate (110), the through hole (112) needs to be formed at a position that avoids the flow path.

[0058] And, in order to form a uniform adhesive surface, it is preferable that the cell lower panel (400) and the base plate (110) form a flat surface without protrusions. To this end, the upper surface of the base plate (110) is provided with a concave surface (114) including a through hole (112), and the body (410) of the cell lower panel (400) is accommodated within the concave surface (114). The upper surface of the body (410) accommodated within the concave surface (114) coincides with the upper surface of the base plate (110), thereby forming a uniform surface contact at the bottom surface of the cell unit (200).

[0059] In addition, as illustrated in FIG. 5, a recess (116) may be provided on the bottom surface of the base plate (110) to accommodate a nut (430) fastened to a stud bolt (420) of the cell lower panel (400) so as not to protrude outward. By accommodating the nut (430) in the recess (116), the bottom surface of the base plate (110) becomes flat, thereby preventing interference with the installation of the battery pack (10) and reducing the risk of the nut (430) becoming loose or damaged. In addition, in order to facilitate the fastening and detaching work of the cell lower panel (400), it is preferable that the size (diameter) of the recess (116) be formed to a size that allows the connection of a tool.

[0060] FIG. 6 is a drawing illustrating an embodiment in which a cooling plate (150) is provided in a battery pack (10) of the present invention. A passage (152) through which a coolant flows is formed inside the cooling plate (150). The low-temperature coolant introduced through the inlet flows along the passage (152) and absorbs heat generated in the cell unit (200) mounted on the base plate (110) in the form of conduction, and the coolant, whose temperature has gradually increased by absorbing the heat, is discharged through the outlet. As described above, heat dissipation of the cell unit (200) is promoted by the cell unit fixing agent (300) having excellent thermal conductivity interposed between the cell unit (200) and the base plate (110) (including the cell lower panel).

[0061] Since the cell lower panel (400) is fastened by penetrating the base plate (110), when the cooling plate (150) is joined to the bottom surface of the base plate (110), the stud bolt (420) of the cell lower panel (400) must be fastened with a nut (430) by penetrating the base plate (110) and the cooling plate (150) as a whole. In this case, in order to prevent the leakage of the refrigerant and not obstruct its flow, it is preferable that the stud bolt (420) and the nut (430) be located in an area where the flow path (152) of the cooling plate (150) is not formed.

[0062]

[0063] [Second Embodiment]

[0064] In the second embodiment of the present invention, the assembly process of the battery pack (10) described above will be described. FIGS. 7 and 8 are drawings illustrating the assembly process of the battery pack (10) according to the present invention.

[0065] First, a pack case (100) for mounting a cell unit (200) is prepared. The pack case (100) may include a base plate (110), a side plate (120) that is coupled along the perimeter of the base plate (110) to form an accommodation space therein, and a cross beam (130) and a center beam (140) that divide the accommodation space inside the base plate (110) longitudinally and transversely. One cell unit (200) is stored in each accommodation space divided by the side plate (120), the cross beam (130), and the center beam (140).

[0066] For each receiving space, a concave surface (114) is formed on the base plate (110), and a through hole (112) is formed in the concave surface (114). The concave surface (114) has a shape into which the body (410) of the cell lower panel (400) can be inserted, and the position and number of the through holes (112) correspond to the stud bolts (420) provided on the cell lower panel (400). The cell lower panel (400) inserted into the concave surface (114) and fastened with the stud bolts (420) on the bottom surface of the base plate (110) with nuts (430) forms a part of the base plate (110).

[0067] For the pack case (100) installed up to the cell lower panel (400) in this way, the cell unit fixing agent (300) is applied. As described above, the cell unit fixing agent (300) includes two types of structural adhesive (310) and non-curing filler (320), and each application area is based on the cell lower panel (400). That is, the structural adhesive (310) is applied above the cell lower panel (400), and the non-curing filler (320) is applied to other areas. In order to easily separate the cell unit (200), care must be taken not to apply the structural adhesive (310) outside the cell lower panel (400).

[0068] Next, as illustrated in Fig. 8, cell units (200) are installed one by one into each receiving space where cell unit fixing agent (300) is applied to each area. The bottom surface of the cell unit (200) is fixed to the base plate (110) by adhesion of the cell unit fixing agent (300).

[0069] Meanwhile, the cell unit (200) includes a plurality of battery cells (210) and a busbar frame assembly (220) that mechanically and electrically couples the plurality of battery cells (210) at both transverse ends from which leads (not shown) of the battery cells (210) protrude. In addition, the cell unit (200) includes a side frame (230) that protects the battery cells (210) on both longitudinal sides.

[0070] In order to secure the cell unit (200) laterally, the side frame (230) of the cell unit (200) is bolted to the upper surface of the cross beam (130). In particular, as illustrated in FIG. 8, the side frame (230) of each cell unit (200) is secured to its assigned cross beam (130), and the side frames (230) of adjacent cell units (200) along the longitudinal direction do not overlap each other on the cross beam (130). That is, when mounting a plurality of cell units (200) in a pack case (100), it is not necessary to follow a set assembly order for mounting, and also, when dismounting one cell unit (200), it is not necessary to first dismount other surrounding cell units (200).

[0071] In this way, since the battery pack (10) of the present invention does not prevent other cell units (200) from interfering with the separation of any cell unit (200), it is possible to separate only the cell unit (200) in which a problem has occurred. In addition, as described with reference to FIG. 3 in the first embodiment, the curable adhesive layer (312) of the structural adhesive (310) that prevents the separation of the cell unit (200) is limited in its area to the cell lower panel (400) that can release the fastening to the base plate (110), and therefore, this also does not affect the separation of the cell unit (200). Therefore, the battery pack (10) of the present invention allows for the easy removal of any cell unit (200) regardless of the assembly order, and thus, the replacement of the battery cell (210) in which a problem has occurred can be easily performed.

[0072]

[0073] The present invention has been described in more detail through drawings and examples. However, the configurations described in the drawings or examples described in this specification are merely embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that various equivalents and modified examples may exist as of the time of this application.

[0074]

[0075] [Explanation of symbols]

[0076] 10: Battery Pack 100: Pack Case

[0077] 110: Base plate 112: Through hole

[0078] 114: Concave surface 116: Recess

[0079] 120: Side plate 130: Cross beam

[0080] 140; Center beam 150: Cooling plate

[0081] 152: Euro 200: Cell Unit

[0082] 210: Battery cell 220: Busbar frame assembly

[0083] 230: Side frame 240: Bolt

[0084] 300: Cell unit fixative 310: Structural adhesive

[0085] 312: Curable adhesive layer 320; Non-curable filler

[0086] 322: Non-curing adhesive layer 400: Cell bottom panel

[0087] 410: Body 420: Stud Bolt

[0088] 430: Nut

Claims

1. A cell unit comprising a plurality of battery cells; A base plate supporting the bottom of the above cell unit; A cell unit fixing agent interposed between the cell unit and the base plate, comprising a structural adhesive applied to or in contact with a portion of the bottom surface of the cell unit and a non-curing filler applied to or in contact with the remaining portion; and A cell lower panel interposed between the base plate and the cell unit fixing member, detachably fastened to the base plate, and adhesively fixed to the cell unit by the structural adhesive; A battery pack comprising:

2. In paragraph 1, The above structural adhesive is, A battery pack that does not encroach on the area outside the above cell lower panel.

3. In paragraph 1, The above cell lower panel is, It comprises a body in which the above structural adhesive is interposed, and a stud bolt extending from the body, The above stud bolts, A battery pack that is secured with a nut through a through hole formed in the above base plate.

4. In paragraph 3, The upper surface of the above base plate is provided with a concave surface including the through hole, A battery pack, wherein the body of the above cell lower panel is accommodated within the above concave surface.

5. In paragraph 4, A battery pack, wherein the upper surface of the body accommodated in the concave surface is aligned with the upper surface of the base plate.

6. In paragraph 3, A battery pack, wherein the bottom surface of the base plate is provided with a recess that allows the connection of a tool while accommodating the nut so that it does not protrude outward.

7. In paragraph 3, A cooling plate is attached to the bottom surface of the above base plate, The above stud bolts and nuts are located in an area of ​​the cooling plate where a flow path is not formed, in a battery pack.

8. In paragraph 3, The above structural adhesive forms a curable adhesive layer, A battery pack, wherein the above non-curable filler forms a non-curable adhesive layer.

9. In paragraph 8, The above cell unit is, By releasing the nut fastening of the above stud bolt, the fixation to the base plate is released, A battery pack, which is pulled out of the pack together with the cell lower panel that is mutually bonded by the structural adhesive.

10. In paragraph 1, The above cell unit fixing agent is, A battery pack, wherein the non-curing filler is disposed on both sides of the structural adhesive.

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