Battery pack

Abstract

The disclosed battery pack includes a cell unit including a plurality of battery cells; a base plate supporting the 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-hardening 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.

Description

[Technical Field]

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

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0094962, filed on July 21, 2023, and all contents disclosed in the documents of said Korean patent application are incorporated herein by reference. [Background technology]

[0003] To improve the space utilization rate of a battery pack, a battery pack with a cell-to-pack structure has been proposed. The cell-to-pack structure has the advantage of improving the space utilization rate of a battery pack by directly assembling multiple battery cells into a battery pack without the need for a modular structure.

[0004] In the cell-to-pack structure, a new structure has been proposed to efficiently mount a large number of battery cells in a pack case by eliminating or simplifying a separate module housing. For example, a structure can be designed in which a side frame is attached to a cell unit (corresponding to a conventional battery module), which is a group of multiple battery cells, and the side frame of the cell unit is fixed to the cross beam of the pack case.

[0005] Alternatively, the side frames of adjacent cell units can be stacked vertically and fixed to the base plate to take the role of a pack cross beam (meaning a cross beam provided in a pack case).Then, by interposing thermal resin between the bottom of the cell unit where the battery cells are exposed and the base plate of the pack case, conductive heat dissipation of the cell unit can be promoted and the cell unit can be fixed more firmly as the thermal resin hardens.

[0006] However, a battery pack structure that uses the side frames of the cell units to omit the construction of a pack cross beam and further fixes the cell units by hardening thermal resin has many advantages in terms of a cell-to-pack structure, such as improving the space utilization rate of the battery pack by directly assembling multiple battery cells into a battery pack without a modular structure, but has disadvantages in terms of battery pack maintenance. That is, this cell-to-pack structure makes it very difficult to disassemble an assembled battery pack into individual cell units.

[0007] For example, a cell-to-pack structure in which the side frames of adjacent cell units are stacked one above the other and fixed to the base plate cannot be disassembled unless the cell units are removed one by one in the reverse order of assembly. Furthermore, a structure in which the bottom of the cell unit is fixed by hardening thermal resin can cause damage to the battery cells bonded to the thermal resin when the cell unit is removed, which can lead to dangerous consequences such as electrolyte leakage.

[0008] There is a strong need for the development of a cell-to-pack battery pack that allows a battery pack to be easily disassembled into individual battery cells, and therefore allows maintenance of the battery pack by replacing the battery cell even if a problem occurs in only one battery cell in the battery pack. This means that expensive battery packs can be used to the end of their designed lifespan without being discarded. Summary of the Invention [Problem to be solved by the invention]

[0009] An object 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 procedure, thereby facilitating the replacement of a defective battery cell.

[0010] However, the technical problems that the present invention aims to solve are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention described below. [Means for solving the problem]

[0011] The present invention relates to a battery pack, which in one example includes a cell unit including a plurality of battery cells, a base plate supporting the bottom surface of the cell unit, a cell unit fixing agent interposed between the cell unit and the base plate and including a structural adhesive applied to or in contact with a portion of the bottom surface of the cell unit and a non-hardening 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 invention, the structural adhesive may not penetrate into areas outside the cell bottom panel.

[0013] The cell lower panel may include a main body in which the structural adhesive is interposed and a stud bolt extending from the main body, and the stud bolt may 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 have a recess including the through-hole, and the main body of the cell lower panel may be received in the recess.

[0015] The upper surface of the main body accommodated in the recess can be flush with the upper surface of the base plate.

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

[0017] According to an embodiment of the present invention, a cooling plate may be coupled to the bottom surface of the base plate, and in this case, the stud bolts and nuts are positioned in an area of ​​the cooling plate where no flow passages are formed.

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

[0019] As a result, the cell unit is released from its fixed state to the base plate by releasing the fastening of the stud bolt nuts, and can be pulled out to the outside of the battery pack together with the cell lower panels interconnected by the structural adhesive.

[0020] The cell unit fixing agent may have the non-hardening filler disposed on both sides of the structural adhesive. [Effects of the Invention]

[0021] In the battery pack of the present invention having the above-described configuration, the structural adhesive that forms a semi-permanent adhesive surface firmly secures the cell unit to the base plate via the cell lower panel, but by making the cell lower panel separable from the base plate, the structural adhesive does not prevent the cell unit from being removed. As a result, even though the cell unit is firmly secured to the base plate by the structural adhesive forming a firm, curable adhesive layer on a portion of the bottom surface of the cell unit, the battery pack of the present invention makes it easy to remove the cell unit by the cell lower panel.

[0022] In addition, in the battery pack of the present invention, the side frames of the cell units are fixed to the top surface of the cross beam with bolts to fix the cell units laterally, but the side frames of adjacent cell units do not overlap each other on the cross beam, which makes it easy to remove a defective cell unit without first separating other surrounding cell units.

[0023] However, the technical effects that can be obtained by the present invention are not limited to the effects described above, and other effects 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 concept of the present invention, so the present invention should not be interpreted as being limited to the matters depicted in such drawings. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a view showing a fixing structure of a cell unit in a battery pack according to the present invention; [Figure 2] FIG. 2 is a cross-sectional view taken along line "AA" in FIG. [Figure 3] 3 is a view showing a state in which the cell unit of FIG. 2 is separated from the battery pack. [Figure 4] 1 is a diagram showing a cell bottom panel. [Figure 5] 1 is a diagram showing the bottom surface of a battery pack. [Figure 6] 1 is a diagram illustrating an embodiment in which a cooling plate is provided in a battery pack. [Figure 7] 1 is a diagram showing an assembly process of a battery pack according to the present invention; [Figure 8] 1 is a diagram showing an assembly process of a battery pack according to the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0026] Because the present invention can be modified in various ways and can have various embodiments, specific embodiments will be described in detail below.

[0027] However, this is not intended to limit the invention to any particular embodiment, but rather it can be understood to include all modifications, equivalents, or alternatives falling within the spirit and scope of the invention.

[0028] In the present invention, terms such as "comprise" and "have" are intended to specify the presence of features, numbers, steps, operations, components, parts or combinations thereof described in the specification, and can be understood as not precluding the presence or possibility of addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0029] Furthermore, in the present invention, when a layer, film, region, plate, or other portion is described as being "on" another portion, this includes not only the case where it is "directly on" the other portion, but also the case where there is another portion therebetween. Conversely, when a layer, film, region, plate, or other portion is described as being "under" the other portion, this includes not only the case where it is "directly under" the other portion, but also the case where there is another portion therebetween. Furthermore, in this application, being "located on" can include not only the case where it is located at the top, but also the case where it is located at the bottom.

[0030] The present invention relates to a battery pack, which in one example includes a cell unit including a plurality of battery cells, a base plate supporting the bottom surface of the cell unit, a cell unit fixing agent interposed between the cell unit and the base plate and including a structural adhesive applied to or in contact with a portion of the bottom surface of the cell unit and a non-hardening 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.

[0031] The structural adhesive forms a curable adhesive layer, and the non-curable filler forms a non-curable adhesive layer, so that the cell lower panel, which has been released from its fixed state to the base plate, can be pulled out of the pack together with the cell units interconnected by the structural adhesive.

[0032] In the battery pack of the present invention having the above-described configuration, the adhesive force for fixing the cell unit to the base plate is provided by both the structural adhesive and the non-hardening filler, but the hardening structural adhesive is locally fixed to the bottom surface of the cell unit, and 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 can both be pulled out to the outside of the pack.

[0033] That is, by limiting the area where the curable structural adhesive is present to the lower cell panel, it becomes easier to separate a defective cell unit from the battery pack, and thus, by replacing only the defective cell unit, the entire battery pack can be reused without being discarded.

[0034] Hereinafter, specific embodiments of the battery pack 10 according to the present invention will be described in detail with reference to the accompanying drawings. For reference, the directions of front, back, up, down, left, and right used in the following description to designate relative positions are intended to facilitate understanding of the invention, and unless otherwise specified, are based on the directions shown in the drawings.

[0035] (First embodiment) FIG. 1 is a view 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 line "AA" in FIG.

[0036] The present invention relates to a battery pack 10, which includes a pack case 100 and a plurality of cell units 200 mounted in the pack case 100. Here, the cell unit 200 refers to a unit in which a plurality of battery cells 210 are bundled together, and includes a structure for unitizing the plurality of battery cells 210. For example, the cell unit 200 may include a bus bar frame assembly 220 that mechanically and electrically couples the plurality of battery cells 210 to both lateral ends from which the leads (not shown) of the battery cells 210 protrude, and side frames 230 that protect the battery cells 210 on both longitudinal ends. Therefore, on the cell unit 200, the plurality of battery cells 210 are aligned in a line along the thickness direction in an upright position. The illustrated cell unit 200 has the battery cells 210 exposed at its bottom without any additional structure, making it compatible with a cell-to-pack battery pack 10.

[0037] The pack case 100 includes a base plate 110. The base plate 110 supports the bottom surface of the cell unit 200, i.e., the bottom surfaces of the plurality of battery cells 210, and functions to absorb heat in the form of thermal conduction through the bottom surface of the cell unit 200 and dissipate the heat to the outside. A heat sink may be built into the base plate 110 itself, or a separate cooling plate 150 may be attached to its bottom surface so that the absorbed heat can be dissipated to the outside via a coolant.

[0038] The pack case 100 may include side plates 120 coupled along the edges of the base plate 110 to form an internal storage space, and cross beams 130 coupled to the base plate 110 to horizontally divide the internal storage space of the base plate 110. In some embodiments, as shown in FIG. 1 , the pack case 100 may further include a center beam 140 that vertically divides the internal storage space of the base plate 110, and thus the cross beams 130 and the center beam 140 may allow the storage space of the pack case 100 to be arranged in a grid pattern.

[0039] One of the fixing structures for the multiple cell units 200 mounted on the base plate 110 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 made of two types of material: a structural adhesive 310 and a non-hardening filler 320. The structural adhesive 310 and the non-hardening filler 320 have in common the fact that they both have high thermal conductivity for smooth heat dissipation, but there are clear differences in their adhesive strength and hardening properties.

[0040] 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 a viscous gel-like property when first applied, but hardens into a hard 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.

[0041] Meanwhile, the non-hardening filler 320 is a cell unit fixing agent 300 that forms a non-hardening adhesive layer 322 between the base plate 110 and the cell unit 200, and has physical properties that do not harden for the life or service warranty period of the battery pack 10 despite temperature fluctuations caused by the passage of time and repeated charging and discharging. The non-hardening filler 320 functions as an adhesive and a buffer, but the adhesive strength of the non-hardening filler 320 is much weaker than that of the structural adhesive 310. Therefore, the non-hardening filler 320 does not act as an obstruction in the process of separating the cell unit 200 from the base plate 110. For example, a gap filler under the trade name "TGF 3010 APS" manufactured by Henkel AG & Co. KGaA, headquartered in Düsseldorf, Germany, may be used as the non-hardening filler 320.

[0042] 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 a structural adhesive 310. The cell lower panel 400 is releasably fastened to the base plate 110, and the structural adhesive 310 is adhered to an upper surface of the cell lower panel 400. As a result, the cell lower panel 400 is adhesively fixed to the cell unit 200 by the structural adhesive 310. Meanwhile, the cell lower panel 400 can be fixed to or separated from the base plate 110.

[0043] 3 is a diagram showing a state in which the cell unit 200 is being separated from the battery pack 10. Before the cell unit 200 is housed in the pack case 100, the cell lower panel 400 is bonded and fixed to the base plate 110. As shown in FIG. 2, the cell unit 200 is adhesively fixed to the base plate 110 by a cell unit fixing agent 300. Of the cell unit fixing agent 300, the hardened structural adhesive 310 fixes the cell unit 200 semi-permanently, and the non-hardening filler 320 adhered to the remaining area of ​​the bottom surface of the cell unit 200 fixes the cell unit 200 with enough adhesive strength that the adhesive surfaces can be separated when an appropriate force is applied.

[0044] In this fixing structure of the cell unit 200, when the cell lower panel 400 is released from the base plate 110 and then the cell unit 200 is removed upward, as shown in Figure 3, the cell lower panel 400, which is fixed with the structural adhesive 310, remains attached to the cell unit 200, while the adhesive surface in the area of ​​the non-hardening filler 320, which has weak adhesive strength, separates. As a result, the cell unit 200 is pulled out of the pack case 100 with the cell lower panel 400 adhered to its bottom surface.

[0045] In other words, the structural adhesive 310, which forms a semi-permanent adhesive surface, firmly secures the base plate 110 and the cell unit 200 via the cell lower panel 400, but because the cell lower panel 400 is separable from the base plate 110, the curable adhesive layer 312 formed by the structural adhesive 310 does not prevent the cell unit 200 from being detached. Furthermore, the non-curable adhesive layer 322 formed by the non-curable filler 320 does not prevent the cell unit 200 from being detached due to the appropriate traction force that acts when the cell unit 200 is detached. As a result, even though a strong curable adhesive layer 312 is formed by the structural adhesive 310 on a portion of the bottom surface of the cell unit 200 and the cell unit 200 is firmly fixed to the base plate 110, the battery pack 10 of the present invention makes it easy to detach the cell unit 200 by the cell lower panel 400.

[0046] To ensure smooth separation of the cell unit 200, it is preferable that the structural adhesive 310 does not penetrate into the outer region of the cell lower panel 400. In other words, it is advantageous for the structural adhesive 310 not to form a curable adhesive layer 312 between the base plate 110 and the cell unit 200 without the cell lower panel 400 being interposed, which is convenient for removing the cell unit 200. It is also preferable that the curable adhesive layer 312 and the non-curable adhesive layer 322 are evenly arranged so that a uniform adhesive force acts on the cell unit 200. To this end, the cell unit fixing agent 300 can be configured so that non-curable filler 320 is arranged on both sides of the structural adhesive 310 located in the center.

[0047] The cell unit fixing agent 300 may be applied to the base plate 110 and the cell lower panel 400, and then the bottom surface of the cell unit 200 may come into contact with the cell unit fixing agent 300, or may be applied directly to the bottom surface of the cell unit 200. However, since the cell lower panel 400 is the criterion for separating the regions of the curable adhesive layer 312 and the non-curable adhesive layer 322, it may be advantageous in terms of process control to apply the cell unit fixing agent 300 on the base plate 110 on which the cell lower panel 400 is installed.

[0048] 4 is a view showing a cell lower panel 400, and FIG. 5 is a view showing the bottom of the battery pack 10. In the illustrated embodiment, the cell lower panel 400 includes a main body 410 with a structural adhesive 310 interposed therebetween, and a stud bolt 420 extending from the main body 410. The stud bolt 420 extending downward from the cell lower panel 400 passes through a through-hole 112 formed in the base plate 110 and is fixed with a nut 430. If the base plate 110 has a built-in heat sink, i.e., if a flow path (not shown) through which a refrigerant flows is formed inside the base plate 110, the through-hole 112 needs to be formed at a position that avoids the flow path.

[0049] To form a uniform adhesive surface, it is preferable that the cell lower panel 400 and the base plate 110 are flat and have no protrusions. To this end, the upper surface of the base plate 110 is provided with a recess 114 including a through-hole 112, and the body 410 of the cell lower panel 400 is received within the recess 114. The upper surface of the body 410 received within the recess 114 coincides with the upper surface of the base plate 110, thereby achieving uniform surface contact with the bottom surface of the cell unit 200.

[0050] 5, the bottom surface of the base plate 110 may be provided with a recess 116 that accommodates the nut 430 fastened to the stud bolt 420 of the cell lower panel 400 so that it does not protrude outward. By accommodating the nut 430 in the recess 116, the bottom surface of the base plate 110 is flat, preventing interference with the installation of the battery pack 10 and reducing the likelihood of the nut 430 becoming loose or damaged. In addition, the size (diameter) of the recess 116 is preferably formed to a size that allows for the connection of a tool so that the fastening and separating operations of the cell lower panel 400 can be easily performed.

[0051] 6 is a diagram showing an embodiment in which a cooling plate 150 is provided in a battery pack 10 of the present invention. A flow path 152 through which a refrigerant flows is formed inside the cooling plate 150. The low-temperature refrigerant that flows into the inlet flows along the flow path 152 and absorbs heat generated from the cell units 200 mounted on the base plate 110 in the form of conduction. The refrigerant, whose temperature gradually increases as it absorbs the heat, is discharged from the outlet. As described above, the cell unit fixing agent 300, which has excellent thermal conductivity and is interposed between the cell units 200 and the base plate 110 (including the lower cell panel), promotes heat dissipation from the cell units 200.

[0052] 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 bolts 420 of the cell lower panel 400 must penetrate the base plate 110 and the cooling plate 150 together and be fastened with nuts 430. In this case, it is preferable that the stud bolts 420 and nuts 430 are located in an area of ​​the cooling plate 150 where the flow channels 152 are not formed, so as to prevent the outflow of the refrigerant and not hinder the flow.

[0053] (Second embodiment) In the second embodiment of the present invention, a description will be given of the assembly process of the above-mentioned battery pack 10. Figures 7 and 8 are diagrams showing the assembly process of the battery pack 10 according to the present invention.

[0054] First, a pack case 100 is prepared for mounting the cell units 200. The pack case 100 may include a base plate 110, side plates 120 that are coupled along the edges of the base plate 110 to form an internal storage space, and a cross beam 130 and center beam 140 that divide the storage space inside the base plate 110 vertically and horizontally. One cell unit 200 is housed in each storage space divided by the side plates 120, cross beam 130, and center beam 140.

[0055] A recess 114 is formed in the base plate 110 for each accommodation space, and through holes 112 are formed in the recess 114. The recess 114 is shaped so that the body 410 of the cell lower panel 400 can be inserted therein, and the positions and number of the through holes 112 correspond to the stud bolts 420 provided in the cell lower panel 400. The cell lower panel 400 inserted into the recess 114 and fastened to the stud bolts 420 by nuts 430 on the bottom surface of the base plate 110 becomes part of the base plate 110.

[0056] The cell unit fixing agent 300 is applied to the pack case 100 with the cell lower panel 400 installed in this manner. As described above, the cell unit fixing agent 300 includes two types of materials: the structural adhesive 310 and the non-hardening filler 320, and the application area of ​​each is based on the cell lower panel 400. In other words, the structural adhesive 310 is applied to the cell lower panel 400, and the non-hardening filler 320 is applied to other areas. To easily separate the cell unit 200, care must be taken to ensure that the structural adhesive 310 is not applied to the outside of the cell lower panel 400.

[0057] 8, the cell units 200 are mounted one by one in each receiving space where the cell unit fixing agent 300 is applied in different regions. The bottom surface of the cell unit 200 is fixed to the base plate 110 by the adhesion of the cell unit fixing agent 300.

[0058] Meanwhile, the cell unit 200 includes a plurality of battery cells 210 and a bus bar frame assembly 220 that mechanically and electrically couples the plurality of battery cells 210 to both lateral ends from which the leads (not shown) of the battery cells 210 protrude. The cell unit 200 also includes side frames 230 on both longitudinal sides that protect the battery cells 210.

[0059] To secure the cell units 200 laterally, the side frames 230 of the cell units 200 are fixed to the upper surfaces of the cross beams 130 with bolts. In particular, as shown in Fig. 8, the side frames 230 of each cell unit 200 are fixed to the cross beams 130 assigned to it, and the side frames 230 of adjacent cell units 200 in the vertical direction do not overlap each other on the cross beams 130. In other words, when installing multiple cell units 200 in the pack case 100, installation does not necessarily require following a set assembly procedure, and when separating one cell unit 200, it is not necessary to first separate the surrounding cell units 200.

[0060] As described above, in the battery pack 10 of the present invention, when any cell unit 200 is separated, other cell units 200 do not interfere with the separation, making it possible to separate only the cell unit 200 in which a problem has occurred. Furthermore, as described in the first embodiment with reference to FIG. 3 , the curable adhesive layer 312 of the structural adhesive 310 that prevents the separation of the cell units 200 is limited in area to the lower cell panel 400, which can be released from the base plate 110, and therefore does not affect the separation of the cell units 200. Therefore, in the battery pack 10 of the present invention, any cell unit 200 can be easily removed regardless of the assembly procedure, thereby facilitating the replacement of a battery cell 210 in which a problem has occurred.

[0061] The present invention has been described in more detail above with reference to the drawings and embodiments, etc. However, the configurations shown in the drawings or embodiments in this specification are merely one embodiment of the present invention and do not represent all of the technical ideas of the present invention, and therefore, at the time of filing this application, there may be various equivalents and modifications that can replace them. [Explanation of symbols]

[0062] 10: Battery pack 100: Pack case 110: Base plate 112:Through hole 114: Concave 116: Dent 120: Side plate 130: Cross beam 140: Center beam 150: Cooling plate 152: Flow path 200: Cell unit 210: Battery cell 220: Busbar frame assembly 230: Side frame 240: Bolt 300: Cell unit fixative 310: Structural adhesives 312: Curable adhesive layer 320: Non-hardening filler 322: Non-curing adhesive layer 400: Cell bottom panel 410:Main body 420: Stud bolt 430: Nut

Claims

1. a cell unit including a plurality of battery cells; a base plate that supports the 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-hardening filler applied to or in contact with the remaining portion; 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.

2. The structural adhesive comprises:

10. The battery pack of claim 1, wherein the battery pack does not intrude into an area outside the cell bottom panel.

3. The cell bottom panel comprises: a body with the structural adhesive interposed therebetween and a stud bolt extending from the body; The stud bolt is The battery pack according to claim 1 or 2, wherein the battery pack is fixed by a nut passing through a through-hole formed in the base plate.

4. The upper surface of the base plate is provided with a concave surface including the through-hole, 4. The battery pack of claim 3, wherein the body of the cell bottom panel is received within the concave surface.

5. The battery pack according to claim 4 , wherein an upper surface of the main body housed in the recess coincides with an upper surface of the base plate.

6. The battery pack according to claim 3 , wherein a recess is provided on a bottom surface of the base plate to accommodate the nut so that it does not protrude outward and to allow connection of a tool.

7. a cooling plate is coupled to the bottom surface of the base plate; The battery pack according to claim 3 , wherein the stud bolt and the nut are located in an area of ​​the cooling plate where no flow passage is formed.

8. The structural adhesive forms a curable adhesive layer; The battery pack according to claim 3 , wherein the non-curable filler forms a non-curable adhesive layer.

9. The cell unit comprises: When the stud bolt is released from the nut, the fixed state with respect to the base plate is released, The battery pack of claim 8 , wherein the battery pack is pulled out to the outside of the battery pack together with the cell bottom panels interconnected by the structural adhesive.

10. The cell unit fixing agent is 3. The battery pack of claim 1, wherein the non-hardening filler is disposed on both sides of the structural adhesive.

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