Battery pack

Abstract

The present invention provides a battery pack that allows for easy separation and replacement of battery cells from the pack housing, has high structural stability, can appropriately control the swelling phenomenon of battery cells in a CTP structure, and has improved cooling efficiency. [Solution] A battery pack is provided, comprising a cell stack in which a plurality of battery cells are stacked, a plurality of cell assemblies each including a cooling member covering at least one surface of the cell stack, and a pack housing that houses the plurality of cell assemblies, wherein the cooling member includes a base plate positioned to face the lower surface of the cell stack; one or more side plates positioned to face the stacking direction of the cell stack and the plurality of battery cells and combined with the pack housing; and a flow path provided across the base plate and the one or more side plates and configured to allow a coolant to flow inside.

Description

Technical Field

[0001] The present invention relates to a battery pack.

Background Art

[0002] Since secondary batteries can be charged and discharged, they are widely used in mobile devices such as digital cameras, mobile phones, and notebook computers. In particular, recently, they have attracted attention as energy sources for electric vehicles, energy storage systems (ESS), etc.

[0003] In electric vehicles and energy storage systems, due to the requirement for high-capacity and high-output power, large-capacity battery devices such as battery modules and battery packs in which a large number of secondary batteries (battery cells) are housed inside a housing are widely used.

[0004] In particular, recently, in order to maximize the energy density of battery devices, technologies related to the CTP (Cell To Pack) structure, which omits the existing battery module case and directly houses a large number of bundled battery cells in a battery pack housing, have emerged.

[0005] However, in the conventional CTP structure, since the battery cells are directly adhered and fixed to the battery pack housing, if a problem occurs in some battery cells at a later date, it has been difficult to separately separate and replace only the corresponding battery cells.

[0006] Also, since the battery cells are directly in contact with the hard battery pack housing, it has been difficult to appropriately buffer and absorb the expansion pressure generated in the battery cells, resulting in a problem of shortening the life of the battery cells.

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present invention was devised to solve at least some of the problems of the prior art described above, and provides a battery pack that allows for easy separation and replacement of battery cells from the pack housing and has high structural stability.

[0008] Furthermore, an object of the present invention is to provide a battery pack that can appropriately control the swelling phenomenon of battery cells in a CTP structure.

[0009] Another objective of the present invention is to provide a battery pack with improved cooling efficiency. [Means for solving the problem]

[0010] To achieve the above objectives, embodiments of the present invention provide a battery pack comprising a cell stack in which a plurality of battery cells are stacked, a plurality of cell assemblies each including a cell stack and a cooling member covering at least one surface of the cell stack; and a pack housing that houses the plurality of cell assemblies, wherein the cooling member includes a base plate positioned opposite the lower surface of the cell stack; one or more side plates positioned opposite the stacking direction of the cell stack and the plurality of battery cells and combined with the pack housing; and a flow path provided across the base plate and the one or more side plates and configured to allow a coolant to flow inside.

[0011] In one embodiment, the pack housing includes a lower frame on which a plurality of cell assemblies are seated; and one or more cross frames positioned on the lower frame to partition the internal space of the pack housing, and one or more side plates may be combined with one or more cross frames.

[0012] In embodiments, one or more side plates may include a first side plate covering one side of the cell stack and having a plurality of first flange portions spaced apart along the longitudinal direction of the cross frame; and a second side plate covering the other side of the cell stack opposite to the one side and having a plurality of second flange portions spaced apart along the longitudinal direction of the cross frame.

[0013] In this embodiment, the multiple first flange portions and the multiple second flange portions can be seated and combined on the upper part of one or more cross frames.

[0014] In the embodiment, the number of multiple first flange portions and the number of multiple second flange portions may differ from each other.

[0015] In this embodiment, the plurality of cell assemblies include a first cell assembly and a second cell assembly adjacent to each other with a cross frame in between, and at least one of the plurality of first flange portions of the first cell assembly may be positioned between the plurality of second flange portions of the second cell assembly.

[0016] In this embodiment, on the upper surface of the cross frame, a plurality of first flange portions of the first cell assembly and a plurality of second flange portions of the second cell assembly may be arranged alternately along the longitudinal direction of the cross frame.

[0017] In one embodiment, the battery pack may further include a fastening member that penetrates at least one of a plurality of first flange portions and a plurality of second flange portions and is fastened to the pack housing.

[0018] In the embodiment, the flow path section may include a first flow path section disposed inside a base plate and configured to allow the refrigerant to flow; and a second flow path section disposed inside one or more side plates and communicating with the first flow path section.

[0019] In the embodiment, the base plate includes a first opening connected to a first flow path, and one or more side plates include a second opening connected to a second flow path, and either the first opening or the second opening may be connected to a refrigerant inlet pipe located inside the pack housing, and the other may be connected to a refrigerant outlet pipe located inside the pack housing.

[0020] In this embodiment, the flow path portion of each of the multiple cell assemblies can be directly connected to the refrigerant inlet and refrigerant outlet pipes.

[0021] In an embodiment, the first flow path section includes a branching point which is the starting point of a branch of one flow path connected to the first opening; a first sub-flow path section and a second sub-flow path section branched by the branching point, wherein one of the first sub-flow path section and the second sub-flow path section may be connected to a second flow path section of a first side plate, and the other may be connected to a second flow path section of a second side plate.

[0022] In an embodiment, the battery pack further includes one or more hollow sections in one or more side plates, separated from the second flow path section, and the one or more hollow sections may have an air gap formed inside.

[0023] In one embodiment, one or more hollow sections are provided inside one or more side plates, and the second flow channel section may be positioned between the multiple hollow sections. [Effects of the Invention]

[0024] According to the embodiment of the battery pack, the battery cells can be easily separated and replaced from the pack housing, which can increase the efficiency of the battery pack manufacturing process and maintainability.

[0025] Furthermore, according to the battery pack of this embodiment, a buffer structure is placed between the battery cell and the pack housing, which allows for proper absorption of expansion pressure due to the swelling phenomenon.

[0026] In addition, since the cell assemblies included in the battery pack of the embodiment have individual cooling channels, a battery pack with excellent cooling performance and small cooling deviation between multiple cell assemblies can be realized.

Brief Description of the Drawings

[0027] [Figure 1] An exemplary configuration of a battery pack is shown. [Figure 2] It is an exploded perspective view of a cell assembly included in a battery pack. [Figure 3] It is a perspective view of a cooling member included in a cell assembly. [Figure 4] It is an exemplary cross-sectional view of a base plate of a cooling member related to the I-I' portion. [Figure 5] It is an exemplary cross-sectional view of a side plate of a cooling member related to the I-I' portion. [Figure 6] It is a top view of a state where a plurality of cell assemblies are arranged inside a pack housing. [Figure 7] It is a top view of a state where a plurality of cell assemblies according to another embodiment are arranged inside a pack housing. [Figure 8] It is a reference diagram for explaining the combination of a plurality of cell assemblies and a pack housing.

Modes for Carrying Out the Invention

[0028] Prior to the detailed description of the present invention, terms and words used in this specification and claims should not be construed as limited to ordinary or dictionary meanings. The inventor must interpret them in meanings and concepts consistent with the technical idea of the present invention based on the principle that he can appropriately define them as concepts of terms in order to explain his own invention in the best way. Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. At the time of this application, there can be various equivalents and modifications that can replace them.

[0029] The same reference numerals or symbols in each of the drawings attached to this specification indicate parts or components that perform substantially the same function. For the sake of explanation and understanding, different embodiments may also be described using the same reference numerals or symbols. That is, even if multiple drawings show components with the same reference numeral, not all of the multiple drawings represent a single embodiment.

[0030] In the following descriptions, singular expressions include plural expressions unless the context clearly indicates otherwise. Terms such as “contains” or “constitutes” are intended to specify the existence of features, figures, stages, operations, components, parts, or combinations thereof described in the specification, and should be understood not to preemptively exclude the existence or possibility of adding one or more different features, figures, stages, operations, components, parts, or combinations thereof.

[0031] Furthermore, in the following explanation, terms such as upper, top, lower, bottom, side, front, and rear are used based on the direction shown in the drawing, and it should be made clear beforehand that they may be expressed differently if the direction of the object in question is changed.

[0032] Furthermore, in this specification and claims, terms including ordinal numbers, such as "first," "second," etc., may be used to distinguish between components. Such ordinal numbers are used to distinguish identical or similar components from one another, and the use of such ordinal numbers should not restrict the meaning of the terms. For example, components combined with such ordinal numbers should not be restricted in terms of their order of use or arrangement by the numbers. Where necessary, the ordinal numbers may be used alternately with each other.

[0033] Embodiments of the present invention will be described in detail below with reference to the attached drawings. However, the spirit of the present invention is not limited to the embodiments presented. For example, a person skilled in the art who understands the spirit of the present invention may propose other embodiments that fall within the scope of the spirit of the present invention through additions, modifications, or deletions of components, and these too would fall within the scope of the spirit of the present invention. In the drawings, the shape and size of elements, etc., may be exaggerated for clearer explanation.

[0034] Figure 1 shows an exemplary configuration of battery pack 1.

[0035] Figure 2 is an exploded perspective view of the cell assembly 10 included in the battery pack 1.

[0036] The battery pack 1 according to this embodiment may include a plurality of cell assemblies 10, each containing a plurality of battery cells 110, and a pack housing that accommodates the plurality of cell assemblies 10.

[0037] Each of the cell assemblies 10 includes a plurality of battery cells 110 and is configured to output or store electrical energy.

[0038] In the cell assembly 10, a plurality of battery cells 110 can be stacked on top of each other to form at least a part of the cell stack 100. The cell assembly 10 may further include a busbar assembly 200 that is electrically connected to the battery cells 110 of the cell stack 100, and an end cover 230 that covers the busbar assembly 200.

[0039] A cell stack 100 may include a plurality of battery cells 110 that are electrically connected to each other. In a single cell stack 100, the plurality of battery cells 110 may be stacked in one direction (for example, in the X-axis direction). In the following description, the stacking direction of the battery cells 110 included in the cell stack 100 will be referred to as the "first direction" or "cell stacking direction".

[0040] The battery cell 110 may be a pouch-type secondary battery having a structure in which an electrode assembly is housed inside a pouch. In a pouch-type secondary battery, the electrode assembly and electrolyte can be housed inside a pouch formed by forming one or more outer materials. However, the battery cell 110 of the cell assembly 10 according to this embodiment is not limited to a pouch-type secondary battery. For example, the battery cell 110 may consist of a rectangular or can-type secondary battery, and it may also have a configuration in which multiple pouch-type secondary batteries are grouped together and formed as a bundle.

[0041] The cell stack 100 may further include cell protection members (not shown) that are positioned between a plurality of battery cells 110 to protect the battery cells 110.

[0042] For example, the cell protection member (not shown) may be a pressure pad that applies a predetermined surface pressure to the battery cell 110 so as to prevent it from swelling during the charging and discharging process. The pressure pad may be made of a material such as polyurethane or silicone, and the elasticity of these materials can be used to pressurize the battery cell 110.

[0043] Alternatively, the cell protection member (not shown) may be an insulating sheet that can block the transfer of high-temperature thermal energy or flames generated in any one of the battery cells 110 to other adjacent components. The insulating sheet is made of a material such as mica, silicate, or ceramic wool, which has excellent flame retardancy, heat resistance, and thermal insulation properties, and can effectively block the propagation of thermal energy generated in the battery cell 110 to the surroundings.

[0044] As shown in Figure 2, multiple cell protection members 120 and multiple battery cells 110 can be stacked along the cell stacking direction (for example, the X-axis direction). However, the number of cell protection members 120 and battery cells 110 constituting the cell stack 100 is not limited to those shown in the drawing. The number of cell protection members 120 and battery cells 110, and the stacking pattern can be varied as needed.

[0045] The cell assembly 10 may further include a busbar assembly 200 that is electrically connected to the battery cells 110 of the cell stack 100.

[0046] Multiple battery cells 110 in the cell stack 100 can be electrically connected to each other through a busbar assembly 200. The busbar assembly 200 may include multiple busbars 210 electrically connected to the battery cells 110 and a busbar frame 220 supporting the busbars 210.

[0047] The busbar 210 may be made of a conductive material (e.g., copper) and serves to electrically connect multiple battery cells 110 to each other. The busbar 210 can be electrically connected to the battery cells 110 while fixed to the busbar frame 220. At least a portion of the busbar 210 may be provided with terminals that can be electrically connected to the external circuit of the cell assembly 10.

[0048] The busbar frame 220 can support the busbars 210 so that they are stably connected to the battery cells 110. The busbar frame 220 may include a non-conductive material (e.g., plastic) having a predetermined rigidity and structurally supports multiple busbars 210.

[0049] The busbar assembly 200 may face at least one side of the cell stack 100. For example, referring to Figure 2, the busbar assembly 200 may be provided in pairs, and the busbar frame 220 may be positioned to face the cell stack 100 and the battery cells 110 in the longitudinal direction (e.g., the Y-axis direction). In the following description, the longitudinal direction of the battery cells 110 will also be referred to as the "second direction," in which case the second direction may be perpendicular to the first direction.

[0050] An end cover 230 may be positioned on the outermost side of one side of the cell assembly 10. The end cover 230 may include a rigid material (e.g., a metal such as aluminum or a resin compound) and can protect the cell laminate 100 from external impacts.

[0051] The end cover 230 can be combined with the busbar assembly 200 or the cell laminate 100 to cover the busbar 210. Although not shown in detail in the drawings, an insulating cover (not shown) containing insulating material may be further placed between the end cover 230 and the busbar assembly 200.

[0052] Multiple cell assemblies 10 can be housed in a pack housing 20. The pack housing 20 may include a lower frame 21 on which the cell assemblies 10 are seated, side frames 22 that combine with the lower frame 21 to form the sides of the pack housing 20, and one or more cross frames 23 positioned on the upper surface of the lower frame 21 to partition the internal space of the pack housing 20. Although not shown in the drawings, the pack housing 20 may further include an upper frame (not shown) that covers the top of the cell assemblies 10 and closes the internal space of the pack housing 20.

[0053] The lower frame 21 forms the lower surface of the pack housing 20. The lower frame 21 may be provided as a rectangular plate-like member or a polygonal plate-like member, but its specific shape is not limited to these.

[0054] Multiple cell assemblies 10 can be seated on the upper side of the lower frame 21. For example, multiple cell assemblies 10 can be arranged on the lower frame 21 along a first direction or a second direction.

[0055] The cross frame 23 can be connected to the lower frame 21. For example, the cross frame 23 can be positioned to penetrate the upper surface of the lower frame 21 in a first or second direction.

[0056] The cross frames 23 can be arranged to partition the internal space of the pack housing 20. For example, on the upper surface of the lower frame 21, multiple cross frames 23 may be arranged spaced apart in a first direction, and one or more cell assemblies 10 may be placed between two adjacent cross frames 23.

[0057] The pack housing 20 may be made of a highly rigid metal material to protect the battery cells 110 located inside. For example, at least a portion of the lower frame 21 or cross frame 23 may include aluminum.

[0058] In one embodiment, the cell assembly 10 can be assembled directly into the pack housing 20 without a separate module case covering the cell assembly 10. This CTP (Cell To Pack) type structure eliminates the space occupied by the module case or assembly tolerances for seating the module case, and the space freed up allows for the placement of more battery cells 110 or larger battery cells 110, thereby increasing the energy density of the battery pack 1.

[0059] However, in conventional CTP-type structures, an adhesive (e.g., thermally conductive adhesive (thermal resin)) was applied between the lower surface of the cell assembly and the pack housing to fix the position of the cell assembly. In this case, once the cell assembly was fixed to the upper side of the lower frame, it became difficult to separate the cell assembly from the pack housing again due to the adhesive force. As a result, if a problem occurred in some of the cell assemblies after multiple cell assemblies had been assembled in the pack housing, it was difficult to isolate and replace only the problematic cell assembly.

[0060] To solve these problems, the battery pack 1 according to the embodiment ensures that the battery cells 110 are not directly bonded to the pack housing 20, but are mechanically fastened to the pack housing 20 via other components, thereby ensuring ease of replacement of the cell assembly 10.

[0061] More specifically, the cell assembly 10 according to the embodiment may further include a cooling member 300 for cooling the cell stack 100, which can be fixedly coupled to the pack housing 20 through the cooling member 300.

[0062] The cooling member 300 may be made of a metal material with excellent thermal conductivity, such as aluminum, and may have a structure that covers at least one surface of the cell stack 100. For example, referring to Figure 2, the cooling member 300 may have a "U" shaped structure composed of a base plate 310 facing the lower surface of the cell stack 100 and two side plates 320 facing each of the two sides of the cell stack 100, and may be configured to cover the lower surface and both sides of the cell stack 100.

[0063] The base plate 310 is positioned to face the cell stack 100 and the cell assembly 10 in the height direction (e.g., the Z-axis direction) and can cover the lower surface of the cell stack 100. In the following description, the height direction of the cell assembly 10 is referred to as the third direction, in which case the third direction may be perpendicular to both the first and second directions.

[0064] The side plate 320 is positioned to face the cell stack 100 in a first direction and can cover the side of the cell stack 100. The side plate 320 can be connected to the end of the base plate 310.

[0065] The base plate 310 and the side plate 320 are provided with flow channels (for example, 311 and 321 in Figure 3) through which the refrigerant can flow, allowing the cell stack 100 to be cooled quickly and effectively.

[0066] An adhesive member {for example, a thermally conductive adhesive (thermal resin)} can be interposed between the cell laminate 100 and the base plate 310, or between the cell laminate 100 and the side plate 320, to fix the cell laminate 100 to the cooling member 300. However, the method of bonding between the cell laminate 100 and the cooling member 300 is not limited to the adhesive method described above. For example, the cell laminate 100 may be fixed to the cooling member 300 through mechanical fastening between the busbar assembly 200, which is combined with one side of the cell laminate 100, and the cooling member 300.

[0067] The cell assembly 10 can be combined with the cross frame 23 of the pack housing 20 through the side plates 320 of the cooling member 300. For example, the side plates 320 of the cooling member 300 may include a plurality of flange portions 324 that project outward from the cell assembly 10, and these flange portions 324 can be combined with the upper part of the cross frame 23. This allows the cell assembly 10 to be firmly fixed inside the pack housing 20 without additional adhesive, and after assembly, the fastening between the side plates 320 and the cross frame 23 can be released to easily separate the cell assembly 10 from the pack housing 20.

[0068] Furthermore, since a cooling member 300 through which all the refrigerant flows is provided for each of the multiple cell assemblies 10, the cooling efficiency can be increased compared to conventional battery pack structures that cool the cell stack through a heat sink located inside or at the bottom of the lower frame of the pack housing.

[0069] On the other hand, when the cell assembly 10 is assembled to the pack housing 20, the side plates 320 of the cooling member 300 can be positioned between the cell stack 100 and the cross frame 23, and can also function to absorb the swelling pressure of the cell stack 100.

[0070] In the following section, the cooling element 300 included in the cell assembly 10 will be described in more detail with reference to Figures 3 to 5.

[0071] Figure 3 is a perspective view of the cooling element 300 included in the cell assembly 10.

[0072] Figure 4 is an exemplary cross-sectional view of the base plate 310 of the cooling member 300 relating to the I-I' portion.

[0073] Figure 5 is an exemplary cross-sectional view of the side plate 320 of the cooling member 300 relating to section I-I'.

[0074] The cooling member 300 described in Figures 3 to 5 includes all the technical features of the cooling member 300 described in Figures 1 and 2, so redundant explanations can be omitted.

[0075] The cooling member 300 may include a base plate 310 positioned opposite the lower surface of the cell stack (100 in Figures 1 and 2), one or more side plates 320 positioned opposite the cell stack 100 in the cell stacking direction, and flow channels 311, 321 configured to allow refrigerant to flow inside.

[0076] The flow channels 311 and 321 can be arranged across the base plate 310 and the side plate 320. For example, referring to Figure 3, the flow channels 311 and 321 may include a first flow channel 311 located inside the base plate 310, and a second flow channel 321 located inside the side plate 320 and communicating with the first flow channel 311.

[0077] The cell stack 100 can be cooled while the refrigerant flows through the flow channels 311 and 321. Here, the refrigerant may be refrigerant that flows in from a refrigerant inlet pipe (for example, 24 in Figures 6 and 7) provided in the pack housing (20 in Figure 1).

[0078] In order to maximize the area over which the cell laminate 100 and the refrigerant exchange heat with each other, the first flow channel 311 and the second flow channel 321 may be provided with multiple bent paths inside the cooling member 300.

[0079] The battery pack according to the embodiment (1 in Figure 1) can be configured such that the refrigerant flowing into the cooling member 300 passes through both the first flow path 311 and the second flow path 321 before being discharged to the outside of the cooling member 300. For example, the base plate 310 may be provided with a first opening 313 connected to the first flow path 311, and the side plate 320 may be provided with a second opening 323 connected to the second flow path 321. The refrigerant inlet pipe of the pack housing 20 (for example, 24 in Figures 6 and 7) may be connected to the second opening 323, and the refrigerant outlet pipe of the pack housing 20 (for example, 25 in Figures 6 and 7) may be connected to the first opening 313. As a result, the refrigerant flowing into the second flow path 321 through the second opening 323 can pass through the second flow path 321 and the first flow path 311 in sequence and be discharged through the first opening 313. That is, in any one of the cooling members 300, the first opening 313 can be used as a refrigerant outlet and the second opening 323 can be used as a refrigerant inlet. However, the refrigerant flow described above is merely illustrative, and if necessary, in any one of the cooling members 300, the first opening 313 may be used as a refrigerant inlet and the second opening 323 as a refrigerant outlet.

[0080] In the cooling member 300, the side plates 320 may be provided in pairs to cover both sides of the cell stack 100. For example, referring to both Figures 2 and 3, the cooling member 300 may include a first side plate 320a that covers one side of the cell stack 100 and a second side plate 320b that covers the other side of the cell stack 100.

[0081] The first side plate 320a and the second side plate 320b may each be provided with a second flow path section 321, and these second flow path sections 321 may all be connected to the first flow path section 311 of the base plate 310. For example, as shown in Figure 3, the first flow path section 311 may include a first sub-flow path section 311a and a second sub-flow path section 311b, from which one flow path connected to the first opening 313 branches off from the branch section 312, and the first sub-flow path section 311a may be connected to the second flow path section 321 of the first side plate 320a, and the second sub-flow path section 311b may be connected to the second flow path section 321 of the second side plate 320b.

[0082] The cooling member 300 according to this embodiment has a base plate 310 that covers three sides of the cell stack 100, and side plates 320, all of which have flow channels 311 and 321 through which the refrigerant flows, allowing the cell stack 100 to be cooled quickly and effectively. In particular, the refrigerant can be flowed not only through the base plate 310 but also through the inside of the side plates 320 that face the cell stack 100 in the cell stacking direction, allowing for so-called "surface cooling" to directly cool a wide surface of the battery cell 110. With such a surface cooling method, the cooling efficiency can be maximized compared to the existing "edge cooling method" that cools the edges of the battery cell (110 in Figure 2).

[0083] On the other hand, referring to both Figures 1 to 3, when the cell assembly 10 is assembled inside the pack housing 20, the side plate 320 of the cooling member 300 is positioned between the cross frame 23 of the pack housing 20 and the cell stack 100, and can perform the function of absorbing the expansion pressure of the cell stack 100. Here, the expansion pressure of the cell stack 100 is generated by the swelling phenomenon in which the battery cells 110 expand during repeated charging and discharging, and in order to prevent shortening of the lifespan and abnormal condition of the battery cells 110, it is necessary to apply appropriate surface pressure to the battery cells 110 to resist this expansion pressure.

[0084] In this embodiment, the cross frame 23 of the pack housing 20 and the side plate 320 of the cooling member 300 are arranged to face the cell stack 100 in the cell stacking direction (for example, the X-axis direction), and a surface pressure can be applied to the battery cells 110 to resist the expansion pressure of the cell stack 100. In particular, the side plate 320 is positioned between the cross frame 23 and the cell stack 100 and can act as a buffer structure to prevent the cell stack 100 from directly contacting the highly rigid cross frame 23 and applying excessive surface pressure to the battery cells 110.

[0085] To more effectively fulfill its role as a buffer structure, a separate hollow section 322 may be provided inside the side plate 320, separated from the second flow channel section 321. The hollow section 322 forms an air gap inside, allowing the side plate 320 to more effectively absorb the expansion pressure of the cell laminate 100.

[0086] The formation of the hollow portion 322 can result in the thickness of the side plate 320 being greater than that of the base plate 310, which does not have the hollow portion 322. For example, referring to the cross-sectional views in Figures 4 and 5, the thickness d1 of the base plate 310 can be less than the thickness d2 of the side plate 320 having the hollow portion 322.

[0087] However, the thicknesses of the base plate 310 and the side plate 320 may be the same as those shown in the drawings. For example, the cross-sectional area of ​​the second flow channel 321 may be made smaller than the cross-sectional area of ​​the first flow channel 311, so that even if the side plate 320 has both the hollow section 322 and the second flow channel 321, its thickness may be the same as that of the base plate 310.

[0088] In this embodiment, multiple hollow portions 322 may be provided inside the side plate 320. For example, referring to the cross-sectional view in Figure 5, two or more hollow portions 322 may be formed inside the side plate 320. In this case, the multiple hollow portions 322 may be spaced apart from each other along the cell stacking direction, and the second flow channel portion 321 may be positioned between the multiple hollow portions 322. With this arrangement, the hollow portion 322 positioned between the second flow channel portion 321 and the cell stack 100 absorbs the expansion pressure of the cell stack 100, preventing the cell stack from expanding and unintentionally deforming the shape of the second flow channel portion 321 of the side plate 320.

[0089] However, the number of hollow sections 322 and their arrangement with respect to the second flow channel section 321 shown in the drawings are merely illustrative and can be varied as needed. For example, the hollow sections 322 may not be positioned between the second flow channel section 321 and the cell laminate 100 in order to minimize interference with heat exchange between the second flow channel section 321 and the cell laminate 100.

[0090] In this embodiment, the base plate 310 and the side plates 320 are provided as separate plate-shaped members and can be combined with each other to form the overall cooling member 300. For example, a pair of individually manufactured side plates 320a and 320b can be welded to both ends of the base plate 310 to form the cooling member 300. In this case, an additional flow path connecting member may be provided to connect the first flow path portion 311 of the base plate 310 and the second flow path portions 321 of the side plates 320a and 320b.

[0091] However, the method for manufacturing the cooling member 300 is not limited to those described above. For example, the cooling member 300 may have an integrated structure formed by bending a single plate-shaped member.

[0092] In embodiments, the side plate 320 may further include a coupling structure for combination with the pack housing 20. For example, referring to Figure 3, the side plate 320 may include one or more flange portions 324 projecting in the direction opposite to the direction toward the cell stack 100. The cooling member 300 may be combined with the pack housing 20 through these flange portions 324, thereby allowing the cell assembly 10 to be fixed inside the pack housing 20.

[0093] The first side plate 320a and the second side plate 320b of the cooling member 300 may each be provided with a plurality of flange portions 324. For example, the first side plate 320a may have a plurality of first flange portions 324a arranged spaced apart from each other along a second direction, and the second side plate 320b may have a plurality of second flange portions 324b arranged spaced apart from each other along a second direction. Here, the second direction may mean the longitudinal direction of the battery cell 110 or the longitudinal direction of the cross frame 23.

[0094] Multiple first flange portions 324a and multiple second flange portions 324b can be seated and assembled on the upper part of the cross frame 23 of the pack housing 20. In this case, in order to further reduce the distance between two adjacent cell assemblies 10, the first flange portions 324a and the second flange portions 324b may be positioned to intersect each other. For example, referring to Figure 3, the first flange portion 324a of the first side plate 320a may be positioned to intersect with the second flange portion 324b of the second side plate 320b so as not to face each other in the cell stacking direction (X-axis direction). With such an arrangement, the arrangement structure of multiple cell assemblies 10 can be configured more efficiently in the narrow space inside the pack housing 20. A detailed explanation of this will be given later through Figures 6 to 8.

[0095] On the other hand, referring to Figure 3, the number of first flange portions 324a and the number of second flange portions 324b in the cooling member 300 can differ from each other. For example, as shown in Figure 3, four first flange portions 324a may be arranged on the first side plate 320a, and three second flange portions 324b may be arranged on the second side plate 320b at positions where they intersect with the first flange portions 324a. However, the number of first flange portions 324a and second flange portions 324b are not limited to those shown in the drawings; it is sufficient that they are arranged at positions where they intersect each other, and they do not necessarily need to be in different quantities from each other.

[0096] The arrangement structure of the multiple cell assemblies 10 will be explained in more detail below, with reference to Figures 6 to 8.

[0097] Figure 6 is a top view showing multiple cell assemblies 10 arranged inside the pack housing 20.

[0098] Figure 7 is a top view showing a plurality of cell assemblies 10 according to another embodiment arranged inside the pack housing 20.

[0099] Figure 8 is a reference diagram illustrating the combination of multiple cell assemblies 10 and pack housings 20.

[0100] The cell assembly 10 and pack housing 20 described in Figures 6 to 8 include all the technical features of the cell assembly 10 and pack housing 20 described in Figures 1 to 5 above, so redundant explanations can be omitted.

[0101] First, referring to Figure 6, multiple cell assemblies 10 can be combined with a cross frame 23 and fixed inside the pack housing 20.

[0102] Multiple cross frames 23 may be spaced apart along the upper surface of the lower frame 21, and one or more cell assemblies 10 may be placed between the cross frames 23. In this case, the cell assemblies 10 may be placed between the cross frames 23 such that the cell stacking direction is parallel to the direction in which the cross frames 23 are spaced apart from each other. With such an arrangement, the cross frames 23 can apply surface pressure to the cell assemblies 100 that resists the expansion pressure generated in the cell stack 100. However, as explained through Figures 3 to 5 above, the side plates 320 of the cooling member 300 act as a buffer between the cross frames 23 and the cell stack 100, so that the cross frames 23, which have high rigidity, do not apply excessive surface pressure to the cell stack 100.

[0103] The side plate 320 of the cooling member 300 includes a plurality of flange portions 324, including a first flange portion 324a and a second flange portion 324b, which can be assembled to the cross frame 23 through these flange portions 324. For example, referring to Figure 8, the flange portions 324 are seated on the upper part of the cross frame 23, and separate fastening members 30, such as bolts, are fastened to the cross frame 23 by passing through the flange portions 324, thereby fixing the cooling member 300 and the cross frame 23 to each other.

[0104] As explained through Figures 3 to 5 above, the first flange portion 324a and the second flange portion 324b may be positioned at intersecting locations. That is, in any one of the cooling members 300, the first flange portion 324a and the second flange portion 324b may be positioned so as not to face each other in the cell stacking direction.

[0105] As a result, when the first cell assembly 10a and the second cell assembly 10b are arranged adjacent to each other with either one of the cross frames 23 in between, the second flange portion 324b of the second cell assembly 10b is positioned between the first flange portions 324a of the first cell assembly 10a. That is, as shown in Figure 6, on the upper surface of the cross frame 23, the first flange portion 324a of the first cell assembly 10a and the second flange portion 324b of the second cell assembly 10b can be arranged alternately along the second direction (Y-axis direction).

[0106] With this structure, the battery pack 1 can form a stable fastening structure between the cell assembly 10 and the pack housing 20 through the flange portion 324, while minimizing space loss due to the protruding structure of the flange portion 324. Specifically, since the first flange portion 324a of the first cell assembly 10a and the second flange portion 324b of the second cell assembly 10b are configured to intersect each other, the gap between the first cell assembly 10a and the second cell assembly 10b can be minimized despite the protruding structure of the flange portion 324. As a result, multiple cell assemblies 10 can be arranged as tightly as possible in the narrow space inside the pack housing 20, and the energy density of the battery pack 1 can be prevented from decreasing while maintaining a robust connection through the flange portion 324.

[0107] Furthermore, by arranging the first flange portion 324a of one of the cell assemblies (e.g., 10a) and the second flange portion 324b of the adjacent cell assembly (e.g., 10b) to intersect with each other, the precise assembly position of the cell assembly 10 can be guided within the pack housing 20, which may also have the effect of increasing the ease of assembly of the battery pack 1.

[0108] The flow channels provided in each cell assembly 10 (311, 321 in Figures 3 to 5) can be connected to refrigerant pipes 24, 25 located inside the pack housing 20. The refrigerant pipes 24, 25 may include a refrigerant inlet pipe 24 connected to an inlet port 26 provided on one side of the pack housing 20, and a refrigerant outlet pipe 25 connected to an outlet port 27, and the flow channels 311, 321 of the cell assembly 10 can be connected to the refrigerant inlet pipe 24 and the refrigerant outlet pipe 25, respectively.

[0109] For example, referring to Figure 6, the cooling member 300 of each cell assembly 10 may be connected to a refrigerant inlet pipe 24 and a refrigerant outlet pipe 25. In this case, the refrigerant inlet pipe 24 and the refrigerant outlet pipe 25 may be connected to either the first opening (313 in Figure 3) or the second opening (323 in Figure 3) of the cooling member 300, respectively. This allows the refrigerant flowing in from outside the pack housing 20 to circulate through the flow channels 311 and 321 of the cooling member 300, cool the cell assembly 10, and then be discharged back to outside the pack housing 20.

[0110] In this embodiment, the flow paths 311 and 321 of the cooling members 300 of each cell assembly 10 can be directly connected to the refrigerant pipes 24 and 25. That is, each individual cooling member 300 can receive a supply of refrigerant directly from the refrigerant inlet pipe 24, and the refrigerant that has cooled one cell assembly 10 does not flow into the cooling members 300 of the other cell assemblies 10, but is immediately discharged into the refrigerant outlet pipe (25). With this refrigerant supply structure, refrigerant is directly injected into the cell assemblies 10 from the refrigerant inlet pipe 24, and cooling deviations between multiple cell assemblies 10 can be minimized.

[0111] On the other hand, in the pack housing 20, the arrangement structure of the refrigerant pipes 24 and 25 can be realized in various ways. For example, as shown in Figure 6, the refrigerant inlet pipe 24 and the refrigerant outlet pipe 25 can be arranged along the central line of the pack housing 20, and the first opening 313 and the second opening 323 of the cooling member 300 can be opened in the same direction and connected to the refrigerant pipes 24 and 25 accordingly.

[0112] Alternatively, as shown in Figure 7, the refrigerant inlet pipe 24 may be positioned along the end of the pack housing 20, and the refrigerant outlet pipe 25 may be positioned along the center line of the pack housing 20, thereby reducing interference between the refrigerant inlet pipe 24 and the refrigerant outlet pipe 25. In this case, the first opening 313 and the second opening 323 of the cooling member 300 may be opened on opposite sides of the cooling member 300. On the other hand, in the embodiment shown in Figure 6 and the embodiment shown in Figure 7, other technical features are identical between them, except for the connection structure between the refrigerant pipes 24, 25 and the cooling member 300.

[0113] In this embodiment, the cell assembly 10 can be easily assembled to and separated from the pack housing 20 through the combination and disassembly of the cooling member 300 and the cross frame 23. For example, as shown in Figure 8, the cell assembly 10 is combined to the pack housing 20 through the combination of the flange portion 324 of the cooling member 300 and the cross frame 23, and an adhesive member 400 may be placed between the cooling member 300 and the battery cell 110, but no separate adhesive member may be placed between the cooling member 300 and the pack housing 20. Therefore, the cell assembly 10 can be easily separated from the pack housing 20 compared to the structure of a conventional battery pack in which the battery cell (or cell assembly including the battery cell) and the pack housing are combined via an adhesive member interposed between them. In particular, such a coupling structure allows for easy separation and replacement of only some cell assemblies that have problems during the manufacturing or use of the battery pack 1, thereby increasing the efficiency of the manufacturing process and the maintainability of the battery pack 1.

[0114] Furthermore, by ensuring a wide contact surface with the cross frame 23 through the flange portion 324 protruding from the side plate 320 of the cooling member 300, the cell assembly 10 can be stably placed and fixed inside the pack housing 20, thereby increasing the structural rigidity of the battery pack 1.

[0115] Furthermore, since the side plates 320 of the cooling member 300 act as a buffer structure between the cross frame 23 and the cell stack 100, excessive surface pressure is prevented from being applied to the cell stack 100, while appropriately absorbing the expansion pressure due to the swelling phenomenon, thereby increasing the lifespan of the battery cells 110.

[0116] Furthermore, since each cell assembly 10 has its own individual cooling channel, it is possible to realize a battery pack 1 with excellent cooling performance and small cooling deviations between multiple cell assemblies 10.

[0117] Although various embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and it will be obvious to anyone with average knowledge of the art that various modifications and variations are possible as long as they do not deviate from the technical idea of ​​the present invention as described in the claims. Furthermore, some components of the above-described embodiments may be omitted, and each embodiment may be combined with others.

[0118] [Explanation of symbols] 1: Battery pack 10: Cell Assembly 20: Pack Housing 21: Lower frame 22: Side frame 23: Cross frame 100: Cell laminate 110: Battery cell 200: Busbar Assembly 300: Cooling component 310: Base plate 311: First channel section 320: Side Plate 321: Second channel section 322: Hollow part 324a: First flange section 324b: Second flange section 400: Adhesive material

Claims

1. A plurality of cell assemblies each including a cell stack in which a plurality of battery cells are stacked and a cooling member covering at least one surface of the cell stack, A pack housing in which the plurality of cell assemblies are housed, The cooling member is A base plate is positioned so as to face the lower surface of the cell stack, One or more side plates are arranged opposite the stacking direction of the cell stack and the plurality of battery cells, and are combined with the pack housing, A battery pack comprising a base plate and one or more side plates, comprising a flow path section configured to allow a refrigerant to flow inside.

2. The aforementioned pack housing is The lower frame on which the plurality of cell assemblies are seated, It includes one or more cross frames arranged on the lower frame to partition the internal space of the pack housing, The battery pack according to claim 1, wherein one or more side plates are combined with one or more cross frames.

3. The one or more side plates mentioned above are A first side plate that covers one side of the cell stack and has a plurality of first flange portions spaced apart along the longitudinal direction of the cross frame, The battery pack according to claim 2, comprising: a second side plate that covers the other side of the cell stack opposite to the one side, and has a plurality of second flange portions spaced apart along the longitudinal direction of the cross frame.

4. The battery pack according to claim 3, wherein the plurality of first flange portions and the plurality of second flange portions are seated and combined on the upper part of one or more cross frames.

5. The battery pack according to claim 3, wherein the number of the plurality of first flange portions and the number of the plurality of second flange portions are different from each other.

6. The plurality of cell assemblies include a first cell assembly and a second cell assembly adjacent to each other with respect to the cross frame, The battery pack according to claim 3, wherein at least one of the plurality of first flange portions of the first cell assembly is positioned between the plurality of second flange portions of the second cell assembly.

7. The battery pack according to claim 6, wherein on the upper surface of the cross frame, the plurality of first flange portions of the first cell assembly and the plurality of second flange portions of the second cell assembly are arranged alternately along the longitudinal direction of the cross frame.

8. The battery pack according to claim 3, further comprising a fastening member that penetrates at least one of the plurality of first flange portions and the plurality of second flange portions and fastens to the pack housing.

9. The aforementioned flow channel section is A first flow path section is disposed inside the base plate and configured to allow the refrigerant to flow, The battery pack according to claim 3, further comprising a second flow channel disposed inside one or more side plates and communicating with the first flow channel.

10. The base plate includes a first opening connected to the first flow path section. The one or more side plates include a second opening connected to the second flow channel, The battery pack according to claim 9, wherein one of the first opening and the second opening is connected to a refrigerant inlet pipe located inside the pack housing, and the other is connected to a refrigerant outlet pipe located inside the pack housing.

11. The battery pack according to claim 10, wherein the flow path portion of each of the plurality of cell assemblies is directly connected to the refrigerant inlet pipe and the refrigerant outlet pipe.

12. The first channel section is, A branching section is the starting point where one flow path connected to the first opening branches off, It includes a first sub-channel section and a second sub-channel section branched by the aforementioned branching section, The battery pack according to claim 10, wherein one of the first sub-flow channel and the second sub-flow channel is connected to the second flow channel of the first side plate, and the other one is connected to the second flow channel of the second side plate.

13. The one or more side plates further include one or more hollow portions separated from the second flow channel portion, The battery pack according to claim 9, wherein one or more of the hollow portions have an air gap formed inside them.

14. The battery pack according to claim 13, wherein the one or more hollow portions are provided inside the one or more side plates, and the second flow channel is arranged between the plurality of hollow portions.

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