Battery pack

Abstract

Provided is a battery pack comprising: a plurality of cell assemblies each of which includes a cell stack comprising a plurality of battery cells stacked together and a cooling member covering at least one surface of the cell stack; and a pack housing in which the plurality of cell assemblies are accommodated, wherein the cooling member includes: a base plate arranged to be opposite to the bottom surface of the cell stack; at least one side plate arranged to be opposite to the cell stack in the stacking direction of the plurality of battery cells and coupled to the pack housing; and a flow path part provided across the base plate and the at least one side plate and configured to allow a refrigerant to flow therethrough.

Description

battery pack

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

[0002] Secondary batteries, capable of being recharged and discharged, are widely used in mobile devices such as digital cameras, cell phones, and laptops. Recently, they have been attracting attention as an energy source for electric vehicles and energy storage systems (ESS).

[0003] As large-capacity and high-output power are required in electric vehicles and power storage devices, large-capacity battery devices such as battery modules and battery packs that house multiple secondary batteries (battery cells) inside a housing are widely utilized.

[0004] In particular, recently, in order to maximize the energy density of a battery device, a technology has emerged regarding a CTP (Cell To Pack) structure that omits the existing battery module case and bundles multiple battery cells and stores them directly in a battery pack housing.

[0005] However, in the conventional CTP structure, since the battery cells are directly in contact with the battery pack housing and are fixed by adhesive, there was a problem in that if a problem occurred in some of the battery cells in the future, it was difficult to replace only the battery cells in question.

[0006] In addition, since the battery cells come into direct contact with the solid battery pack housing, there was a problem in that the expansion pressure generated in the battery cells was difficult to properly buffer and absorb, which caused a shortening of the lifespan of the battery cells.

[0007] The present invention has been devised to solve at least some of the problems of the prior art as described above, and provides a battery pack having high structural stability while allowing battery cells to be easily separated and replaced from a pack housing.

[0008] In addition, an object of the present invention is to provide a battery pack capable of appropriately controlling the swelling phenomenon of a battery cell in a CTP structure.

[0009] In addition, it is an object of the present invention to provide a battery pack with improved cooling efficiency.

[0010] In order to achieve the above object, in embodiments of the present invention, a battery pack is provided, including a plurality of cell assemblies, each including a cell stack having a plurality of battery cells stacked thereon and a cooling member surrounding at least one surface of the cell stack; and a pack housing in which the plurality of cell assemblies are accommodated, wherein the cooling member includes a base plate arranged to face a lower surface of the cell stack; one or more side plates arranged to face the cell stack and the plurality of battery cells in a stacking direction and coupled to the pack housing; and a flow path portion provided across the base plate and the one or more side plates and configured to allow a coolant to flow therein.

[0011] In embodiments, the pack housing includes a lower frame on which a plurality of cell assemblies are mounted; and one or more cross frames disposed on the lower frame to define an interior space of the pack housing, wherein one or more side plates can be coupled to 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 the one side and having a plurality of second flange portions spaced apart along the longitudinal direction of the cross frame.

[0013] In embodiments, a plurality of first flange portions and a plurality of second flange portions may be mounted and joined to the upper portion of one or more cross frames.

[0014] In embodiments, the number of the plurality of first flange portions and the number of the plurality of second flange portions may be different from each other.

[0015] In embodiments, the plurality of cell assemblies include a first cell assembly and a second cell assembly adjacent to each other with a cross frame therebetween, and at least one of the plurality of first flange portions of the first cell assembly can be disposed between the plurality of second flange portions of the second cell assembly.

[0016] In embodiments, 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 alternately arranged along the longitudinal direction of the cross frame.

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

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

[0019] In embodiments, the base plate includes a first opening connected to the first flow section, and one or more side plates include a second opening connected to the second flow section, wherein one of the first opening and the second opening is connected to a refrigerant inlet pipe disposed inside the pack housing, and the other is connected to a refrigerant discharge pipe disposed inside the pack housing.

[0020] In embodiments, the refrigerant portion of each of the plurality of cell assemblies may be directly connected to a refrigerant inlet pipe and a refrigerant discharge pipe.

[0021] In embodiments, the first flow path portion includes a branch portion, which is a starting point from which a flow path connected to the first opening branches; a first sub-flow path portion and a second sub-flow path portion branched by the branch portion, wherein one of the first sub-flow path portion and the second sub-flow path portion can be connected to the second flow path portion of the first side plate, and the other can be connected to the second flow path portion of the second side plate.

[0022] In embodiments, the battery pack further includes one or more side plates, one or more hollow portions separated from the second euro portion, and one or more hollow portions may have an air gap formed therein.

[0023] In embodiments, one or more hollow portions may be provided in multiple numbers within one or more side plates, and the second flow portion may be positioned between the plurality of hollow portions.

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

[0025] Additionally, according to the battery pack of the embodiments, a buffer structure is arranged between the battery cell and the pack housing to appropriately absorb expansion pressure due to the swelling phenomenon.

[0026] In addition, the cell assemblies included in the battery packs of the embodiments have individual cooling channels, thereby enabling implementation of a battery pack with excellent cooling performance and small cooling deviation between multiple cell assemblies.

[0027] Figure 1 shows an exemplary configuration of a battery pack.

[0028] Figure 2 is an exploded perspective view of a cell assembly included in a battery pack.

[0029] Figure 3 is a perspective view of a cooling member included in a cell assembly.

[0030] Fig. 4 is an exemplary cross-sectional view of a base plate of a cooling member according to part II'.

[0031] Fig. 5 is an exemplary cross-sectional view of a side plate of a cooling member according to part II'.

[0032] Figure 6 is a top view of a state in which multiple cell assemblies are arranged inside a pack housing.

[0033] FIG. 7 is a top view of a plurality of cell assemblies arranged inside a pack housing according to another embodiment.

[0034] Figure 8 is a reference drawing for explaining the combination of a plurality of cell assemblies and a pack housing.

[0035] Before going into the detailed description of the present invention, it should be noted that the terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted with meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term in order to explain his own invention in the best way. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical idea of ​​the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of this application.

[0036] The same reference numbers or symbols used in each drawing attached to this specification represent parts or components that perform substantially the same functions. For convenience of explanation and understanding, the same reference numbers or symbols may be used in different embodiments. In other words, even if components with the same reference numbers are depicted in multiple drawings, they do not necessarily represent a single embodiment.

[0037] In the following description, singular expressions include plural expressions unless the context clearly indicates otherwise. Terms such as "comprises" or "comprises" should be understood to indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0038] In addition, in the description below, expressions such as top, upper, lower, lower, side, front, and rear are expressed based on the direction shown in the drawing, and it is noted in advance that they may be expressed differently if the direction of the object in question changes.

[0039] Additionally, terms including ordinal numbers, such as "first," "second," etc., may be used in this specification and claims to distinguish between components. These ordinal numbers are used to distinguish identical or similar components from each other, and the use of these ordinal numbers should not be interpreted in a limited manner. For example, components associated with these ordinals should not be interpreted in a restricted manner, such as in the order of use or arrangement, based on their numbers. If necessary, each ordinal number may be used interchangeably.

[0040] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. However, the spirit of the present invention is not limited to the presented embodiments. For example, those skilled in the art who understand the spirit of the present invention may propose other embodiments within the spirit of the present invention by adding, modifying, or deleting components, etc., but such embodiments will also be considered to be within the spirit of the present invention. The shapes and sizes of elements in the drawings may be exaggerated for clarity.

[0041] Fig. 1 shows an exemplary configuration of a battery pack (1).

[0042] Figure 2 is an exploded perspective view of a cell assembly (10) included in a battery pack (1).

[0043] A battery pack (1) according to embodiments may include a plurality of cell assemblies (10) each including a plurality of battery cells (110) and a pack housing in which the plurality of cell assemblies (10) are accommodated.

[0044] Each of the plurality of cell assemblies (10) includes a plurality of battery cells (110) and is configured to output or store electrical energy.

[0045] In the cell assembly (10), a plurality of battery cells (110) may be stacked on each other to form at least a portion of the cell stack (100). The cell assembly (10) may further include a busbar assembly (200) electrically connected to the battery cells (110) of the cell stack (100), and an end cover (230) covering the busbar assembly (200).

[0046] A cell stack (100) may include a plurality of battery cells (110) that are electrically connected to each other. In one cell stack (100), the plurality of battery cells (110) may be stacked in one direction (e.g., the X-axis direction). In the following description, the stacking direction of the battery cells (110) included in the cell stack (100) is referred to as a 'first direction' or a 'cell stacking direction'.

[0047] 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 the pouch-type secondary battery, the electrode assembly and the electrolyte may 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 the embodiments is not limited to a pouch-type secondary battery. For example, the battery cell (110) may be configured as a square or can-type secondary battery, and may also have a configuration in which a plurality of pouch-type secondary batteries are grouped together to form a bundle.

[0048] The cell stack (100) may further include a cell protection member (not shown) that is positioned between a plurality of battery cells (110) to protect the battery cells (110).

[0049] For example, the cell protection member (not shown) may be a pressure pad that can apply a predetermined pressure to the battery cell (110) to prevent the battery cell (110) from swelling during the charging and discharging process. The pressure pad may be made of a material such as polyurethane or silicone, and can apply pressure to the battery cell (110) by utilizing the elasticity of these materials.

[0050] Alternatively, the cell protection member (not shown) may be an insulating sheet capable of blocking high-temperature thermal energy or flame generated from one battery cell (110) from being transferred to other neighboring 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 thermal energy generated from the battery cell (110) from being transmitted to the surroundings.

[0051] As illustrated in FIG. 2, a plurality of cell protection members (120) and a plurality of battery cells (110) may be stacked along a cell stacking direction (e.g., X-axis direction). However, the number of cell protection members (120) and battery cells (110) constituting the cell stack (100) is not limited to that illustrated in the drawing. The number and stacking pattern of the cell protection members (120) and battery cells (110) may be varied as needed.

[0052] The cell assembly (10) may further include a busbar assembly (200) electrically connected to the battery cells (110) of the cell stack (100).

[0053] A plurality of battery cells (110) of a cell stack (100) can be electrically connected to each other through a busbar assembly (200). The busbar assembly (200) can include a plurality of busbars (210) electrically connected to the battery cells (110) and a busbar frame (220) supporting the busbars (210).

[0054] The busbar (210) may be formed of a conductive material (e.g., copper) and serves to electrically connect a plurality of battery cells (110) to each other. The busbar (210) may be electrically connected to the battery cells (110) while being fixed to the busbar frame (220). At least some of the busbars (210) may be provided with terminals that can be electrically connected to an external circuit of the cell assembly (10).

[0055] The busbar frame (220) can support the busbar (210) so that it is stably connected to the battery cell (110). The busbar frame (220) can include a non-conductive material (e.g., plastic) having a predetermined rigidity and structurally supports a plurality of busbars (210).

[0056] The busbar assembly (200) may be positioned opposite at least one side of the cell stack (100). For example, referring to FIG. 2, the busbar assembly (200) may be provided as a pair, and the busbar frame (220) may be positioned to face the cell stack (100) and the battery cell (110) in the longitudinal direction (e.g., Y-axis direction). In the following description, the longitudinal direction of the battery cell (110) may also be referred to as a “second direction,” and in this case, the second direction may be a direction perpendicular to the first direction.

[0057] An end cover (230) may be placed on one outermost side of the cell assembly (10). The end cover (230) may include a material having rigidity (e.g., a metal such as aluminum or a resin compound) to protect the cell stack (100) from external impact.

[0058] The end cover (230) can be coupled to the busbar assembly (200) or the cell stack (100) to cover the busbar (210). Although not shown in detail in the drawing, an insulating cover (not shown) including an insulating material can be further placed between the end cover (230) and the busbar assembly (200).

[0059] A plurality of cell assemblies (10) can be accommodated in a pack housing (20). The pack housing (20) can include a lower frame (21) on which the cell assemblies (10) are mounted, a side frame (22) coupled to the lower frame (21) to form a side surface of the pack housing (20), and one or more cross frames (23) arranged on the upper surface of the lower frame (21) to partition the internal space of the pack housing (20). Although not shown in the drawing, the pack housing (20) can further include an upper frame (not shown) that covers the upper portion of the cell assemblies (10) to close the internal space of the pack housing (20).

[0060] The lower frame (21) forms the lower surface of the pack housing (20). The lower frame (21) may be provided as a square plate-shaped member or a polygonal plate-shaped member, but its specific shape is not limited thereto.

[0061] A plurality of cell assemblies (10) can be mounted on the upper side of the lower frame (21). For example, the plurality of cell assemblies (10) can be arranged along a first direction or a second direction on the lower frame (21).

[0062] The cross frame (23) can be connected to the lower frame (21). For example, the cross frame (23) can be arranged to cross the upper surface of the lower frame (21) in the first direction or the second direction.

[0063] 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), a plurality of cross frames (23) can be arranged spaced apart in the first direction, and one or more cell assemblies (10) can be arranged between two adjacent cross frames (23).

[0064] The pack housing (20) may be formed of a metal material having high rigidity so as to protect the battery cells (110) placed inside. For example, at least a portion of the lower frame (21) or the cross frame (23) may include aluminum.

[0065] In embodiments, the cell assembly (10) can be directly assembled into the pack housing (20) without a separate module case surrounding the cell assembly (10). According to this CTP (Cell To Pack) type structure, the space occupied by the module case or the assembly tolerance for module case installation can be eliminated, and a larger number of battery cells (110) or larger-sized battery cells (110) can be arranged by the eliminated space, thereby increasing the energy density of the battery pack (1).

[0066] However, in the conventional CTP type structure, an adhesive (e.g., thermal resin) is applied between the lower surface of the cell assembly and the pack housing to fix the position of the cell assembly. In this case, after the cell assembly is fixed to the upper side of the lower frame, it is difficult to separate the cell assembly from the pack housing again due to the adhesive strength of the adhesive. Accordingly, when a problem occurs in some of the cell assemblies after a plurality of cell assemblies are assembled into the pack housing, there is a problem in that it is difficult to separate and replace only the problematic cell assembly.

[0067] To solve these problems, the battery pack (1) according to the embodiments ensures ease of replacement of the cell assembly (10) by mechanically fastening the battery cell (110) to the pack housing (20) via another component rather than directly adhesively fixing the battery cell (110) to the pack housing (20).

[0068] More specifically, the cell assembly (10) according to the embodiments may further include a cooling member (300) for cooling the cell stack (100), and may be fixedly connected to the pack housing (20) through the cooling member (300).

[0069] The cooling member (300) may be formed of a metal material with excellent thermal conductivity, such as aluminum, and may have a structure that surrounds at least one surface of the cell stack (100). For example, referring to FIG. 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 side surfaces of the cell stack (100), so as to surround the lower surface and both side surfaces of the cell stack (100).

[0070] The base plate (310) may be arranged to face the cell stack (100) and the cell assembly (10) in the height direction (e.g., Z-axis direction) so as to 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 a third direction, and in this case, the third direction may be a direction perpendicular to both the first direction and the second direction.

[0071] The side plate (320) can be arranged to face the cell stack (100) in the first direction and cover the side surface of the cell stack (100). The side plate (320) can be connected to the edge of the base plate (310).

[0072] A flow path (e.g., 311, 321 in FIG. 3) through which a coolant can flow is provided inside the base plate (310) and the side plate (320), so that the cell stack (100) can be cooled quickly and effectively.

[0073] An adhesive material (e.g., thermal resin) may be interposed between the cell stack (100) and the base plate (310), or between the cell stack (100) and the side plate (320), to fix the cell stack (100) to the cooling member (300). However, the method of bonding between the cell stack (100) and the cooling member (300) is not limited to the above-described bonding method. For example, the cell stack (100) may be fixed to the cooling member (300) through mechanical fastening between the busbar assembly (200) bonded to one side of the cell stack (100) and the cooling member (300).

[0074] The cell assembly (10) can be coupled to the cross frame (23) of the pack housing (20) via the side plate (320) of the cooling member (300). For example, the side plate (320) of the cooling member (300) can include a plurality of flange portions (324) protruding in the outer direction of the cell assembly (10), and the flange portions (324) can be coupled to the upper portion of the cross frame (23). Accordingly, the cell assembly (10) can be firmly fixed to the interior of the pack housing (20) without a separate adhesive, and even after assembly, the cell assembly (10) can be easily separated from the pack housing (20) by disengaging the fastening between the side plate (320) and the cross frame (23).

[0075] In addition, a cooling member (300) through which a coolant flows is arranged in each of a plurality of cell assemblies (10), so that cooling efficiency can be increased compared to a conventional battery pack structure that cools the cell stack through a heat sink arranged inside or at the bottom of the lower frame of the pack housing.

[0076] Meanwhile, in a state where the cell assembly (10) is coupled to the pack housing (20), the side plate (320) of the cooling member (300) may be placed between the cell stack (100) and the cross frame (23) to perform the function of absorbing the swelling pressure of the cell stack (100).

[0077] Hereinafter, the cooling member (300) included in the cell assembly (10) will be described in more detail with reference to FIGS. 3 to 5.

[0078] Figure 3 is a perspective view of a cooling member (300) included in a cell assembly (10).

[0079] FIG. 4 is an exemplary cross-sectional view of a base plate (310) of a cooling member (300) according to part II'.

[0080] FIG. 5 is an exemplary cross-sectional view of a side plate (320) of a cooling member (300) according to part II'.

[0081] The cooling member (300) described in FIGS. 3 to 5 includes all the technical features of the cooling member (300) described through FIGS. 1 and 2, so redundant descriptions may be omitted.

[0082] The cooling member (300) may include a base plate (310) arranged to face the lower surface of the cell stack (100 of FIGS. 1 and 2), one or more side plates (320) arranged to face the cell stack (100) in the cell stacking direction, and a flow path (311, 321) configured to allow refrigerant to flow therein.

[0083] The flow paths (311, 321) may be arranged across the base plate (310) and the side plate (320). For example, referring to FIG. 3, the flow paths (311, 321) may include a first flow path (311) arranged inside the base plate (310) and a second flow path (321) arranged inside the side plate (320) and communicating with the first flow path (311).

[0084] A refrigerant can flow inside the refrigerant section (311, 321) to cool the cell stack (100). Here, the refrigerant may be refrigerant introduced from a refrigerant inlet pipe (e.g., 24 in FIGS. 6 and 7) provided in the pack housing (20 in FIG. 1).

[0085] In order to maximize the area where the cell stack (100) and the refrigerant exchange heat, the first flow path (311) and the second flow path (321) may be provided to have a path that is bent multiple times inside the cooling member (300).

[0086] The battery pack (1 in FIG. 1) according to the embodiments may be configured so that the coolant introduced into the cooling member (300) passes through both the first flow path section (311) and the second flow path section (321) and then exits to the outside of the cooling member (300). For example, a first opening section (313) connected to the first flow path section (311) may be provided in the base plate (310), a second opening section (323) connected to the second flow path section (321) may be provided in the side plate (320), and a coolant inlet pipe (e.g., 24 in FIGS. 6 and 7) of the pack housing (20) may be connected to the second opening section (323), and a coolant discharge pipe (e.g., 25 in FIGS. 6 and 7) of the pack housing (20) may be connected to the first opening section (313). Accordingly, the refrigerant introduced into the second flow path (321) through the second opening (323) can sequentially pass through the second flow path (321) and the first flow path (311) and then exit through the first opening (313). That is, in one cooling member (300), the first opening (313) can be utilized as a refrigerant outlet, and the second opening (323) can be utilized as a refrigerant inlet. However, the above-described flow of the refrigerant is merely an example, and, if necessary, the first opening (313) can be utilized as a refrigerant inlet, and the second opening (323) can be utilized as a refrigerant outlet, in one cooling member (300).

[0087] 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 FIGS. 2 and 3 together, the cooling member (300) may include a first side plate (320a) covering one side of the cell stack (100) and a second side plate (320b) covering the other side of the cell stack (100).

[0088] 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 FIG. 3, the first flow path section (311) may include a first sub-flow path section (311a) and a second sub-flow path section (311b), in 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).

[0089] The cooling member (300) according to the embodiments has a flow path (311, 321) through which a coolant flows, arranged in both the base plate (310) and the side plate (320) covering three sides of the cell stack (100), so as to cool the cell stack (100) quickly and effectively. In particular, the coolant is allowed to flow not only in the base plate (310) but also inside the side plate (320) facing the cell stacking direction to directly cool a wide surface of the battery cell (110), so-called 'surface cooling method' cooling can be performed. In the case of this surface cooling method, the cooling efficiency can be maximized compared to the existing 'edge cooling method' that cools the edge of the battery cell (110 in FIG. 2).

[0090] Meanwhile, referring to FIGS. 1 to 3 together, as the cell assembly (10) is coupled inside the pack housing (20), the side plate (320) of the cooling member (300) is disposed between the cross frame (23) of the pack housing (20) and the cell stack (100), so as to perform a function of absorbing the expansion pressure of the cell stack (100). Here, the expansion pressure of the cell stack (100) is generated by a swelling phenomenon in which the battery cell (110) swells while being repeatedly charged and discharged, and in order to prevent shortening of the lifespan of the battery cell (110) and abnormal condition, it is necessary to apply an appropriate surface pressure to the battery cell (110) to resist this expansion pressure.

[0091] In the embodiments, 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 (e.g., X-axis direction) so as to apply surface pressure to the battery cell (110) that resists the expansion pressure of the cell stack (100). In particular, the side plate (320) is arranged between the cross frame (23) and the cell stack (100) so as to serve as a buffer structure that prevents the cell stack (100) from directly contacting the cross frame (23) having high rigidity and thereby preventing an excessive surface pressure from being applied to the battery cell (110).

[0092] In order to more effectively perform the role of a buffer structure, a separate hollow portion (322) separated from the second flow portion (321) may be provided inside the side plate (320). An air gap is formed inside the hollow portion (322), allowing the side plate (320) to more effectively absorb the expansion pressure of the cell stack (100).

[0093] As the hollow portion (322) is formed, the thickness of the side plate (320) may be thicker than the thickness of the base plate (310) in which the hollow portion (322) is not formed. For example, referring to the cross-sectional views of FIGS. 4 and 5, the thickness (d1) of the base plate (310) may be smaller than the thickness (d2) of the side plate (320) having the hollow portion (322).

[0094] However, the thickness of the base plate (310) and the side plate (320) may be provided to be the same as each other, unlike what is shown in the drawing. For example, the cross-sectional area of ​​the second flow path section (321) may be made smaller than the cross-sectional area of ​​the first flow path section (311), so that even if the side plate (320) has both the hollow portion (322) and the second flow path section (321), its thickness may be configured to be the same as that of the base plate (310).

[0095] In embodiments, a plurality of hollow portions (322) may be provided inside the side plate (320). For example, referring to the cross-sectional view of FIG. 5, two or more hollow portions (322) may be formed inside the side plate (320). In this case, the plurality of hollow portions (322) may be spaced apart from each other along the cell stacking direction, and the second flow path portion (321) may be arranged between the plurality of hollow portions (322). According to this arrangement structure, the hollow portion (322) arranged between the second flow path portion (321) and the cell stack (100) absorbs the expansion pressure of the cell stack (100), thereby preventing the shape of the second flow path portion (321) of the side plate (320) from being unintentionally deformed as the cell stack expands.

[0096] However, the number of hollow parts (322) shown in the drawing and their arrangement relationship with the second flow path (321) are merely examples and may be modified in various ways as needed. For example, in order to minimize the interference with heat exchange between the second flow path (321) and the cell stack (100), the hollow parts (322) may not be arranged between the second flow path (321) and the cell stack (100).

[0097] In embodiments, the base plate (310) and the side plate (320) may be provided as separate plate-shaped members and joined together to form the entire cooling member (300). For example, a pair of individually manufactured side plates (320a, 320b) may be welded to both edges of the base plate (310) to form the cooling member (300). In this case, a flow path connecting member connecting the first flow path section (311) of the base plate (310) and the second flow path section (321) of the side plates (320a, 320b) may be additionally provided.

[0098] However, the method of manufacturing the cooling member (300) is not limited to what has been described above. For example, the cooling member (300) may have an integral structure formed by bending a single plate-shaped member.

[0099] In embodiments, the side plate (320) may further include a coupling structure for coupling with the pack housing (20). For example, referring to FIG. 3, the side plate (320) may include one or more flange portions (324) that protrude in a direction opposite to the direction toward the cell stack (100). The cooling member (300) may be coupled to the pack housing (20) via the flange portions (324), thereby allowing the cell assembly (10) to be fixed inside the pack housing (20).

[0100] 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 be provided with a plurality of first flange portions (324a) spaced apart from each other along the second direction, and the second side plate (320b) may be provided with a plurality of second flange portions (324b) spaced apart from each other along the 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).

[0101] A plurality of first flange portions (324a) and a plurality of second flange portions (324b) may be mounted and coupled to the upper portion of the cross frame (23) of the pack housing (20). In this case, in order to further narrow the gap between two adjacent cell assemblies (10), the first flange portions (324a) and the second flange portions (324b) may be arranged at staggered positions. For example, referring to FIG. 3, the first flange portion (324a) of the first side plate (320a) may be arranged at staggered positions so as not to face the second flange portion (324b) of the second side plate (320b) in the cell stacking direction (X-axis direction). According to this arrangement structure, the arrangement structure of the plurality of cell assemblies (10) can be configured more efficiently in a narrow space inside the pack housing (20). A detailed description thereof will be described later with reference to FIGS. 6 to 8.

[0102] Meanwhile, with continued reference to FIG. 3, the number of first flange parts (324a) and the number of second flange parts (324b) in the cooling member (300) may be different from each other. For example, as shown in FIG. 3, four first flange parts (324a) may be arranged on the first side plate (320a), and three second flange parts (324b) may be arranged on the second side plate (320b) at positions that are interlaced with the first flange parts (324a). However, the number of first flange parts (324a) and the number of second flange parts (324b) are not limited to those shown in the drawing, and it is sufficient if they are arranged at interlaced positions, and it is not necessary to provide them in different quantities.

[0103] Hereinafter, the arrangement structure of multiple cell assemblies (10) will be described in more detail with reference to FIGS. 6 to 8.

[0104] Figure 6 is a top view of a state in which multiple cell assemblies (10) are arranged inside a pack housing (20).

[0105] FIG. 7 is a top view of a state in which a plurality of cell assemblies (10) according to another embodiment are arranged inside a pack housing (20).

[0106] Figure 8 is a reference drawing for explaining the combination of a plurality of cell assemblies (10) and a pack housing (20).

[0107] The cell assembly (10) and pack housing (20) described in FIGS. 6 to 8 include all of the technical features of the cell assembly (10) and pack housing (20) described in FIGS. 1 to 5, so redundant descriptions may be omitted.

[0108] First, referring to FIG. 6, a plurality of cell assemblies (10) can be coupled to a cross frame (23) and fixed inside a pack housing (20).

[0109] A plurality of cross frames (23) may be spaced apart from each other along the upper surface of the lower frame (21), and one or more cell assemblies (10) may be arranged between the cross frames (23). In this case, the cell assemblies (10) may be arranged between the cross frames (23) such that the cell stacking direction is parallel to the direction in which the cross frames (23) are spaced from each other. According to this arrangement structure, the cross frames (23) may apply a surface pressure to the cell assembly (10) that resists the expansion pressure generated in the cell stack (100). However, as described above with reference to FIGS. 3 to 5, the side plates (320) of the cooling member (300) act as a buffer between the cross frames (23) and the cell stack (100), thereby preventing an excessive surface pressure from being applied to the cell stack (100) by the cross frames (23) having strong rigidity.

[0110] 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), and can be coupled to the cross frame (23) through these flange portions (324). For example, referring to FIG. 8, the flange portion (324) is mounted on the upper portion of the cross frame (23), and a separate fastening member (30), such as a bolt, is fastened to the cross frame (23) by passing through the flange portion (324), so that the cooling member (300) and the cross frame (23) can be fixed to each other.

[0111] As previously described with reference to FIGS. 3 to 5, the first flange portion (324a) and the second flange portion (324b) may be arranged at staggered positions. That is, in one cooling member (300), the first flange portion (324a) and the second flange portion (324b) may be arranged at staggered positions so as not to face each other in the cell stacking direction.

[0112] Accordingly, when the first cell assembly (10a) and the second cell assembly (10b) are arranged adjacent to each other with one cross frame (23) therebetween, the second flange portion (324b) of the second cell assembly (10b) is arranged between the first flange portion (324a) of the first cell assembly (10a). That is, as shown in Fig. 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).

[0113] According to this structure, a stable fastening structure can be formed between the cell assembly (10) and the pack housing (20) through the flange portion (324) in the battery pack (1), while minimizing space consumption due to the protruding structure of the flange portion (324). That is, 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 be staggered from each other, so that the gap between the first cell assembly (10a) and the second cell assembly (10b) can be narrowed as much as possible despite the protruding structure such as the flange portion (324). Accordingly, a plurality of cell assemblies (10) can be arranged as closely as possible in a narrow space inside the pack housing (20), thereby ensuring a strong fastening structure through the flange portion (324) while preventing the energy density of the battery pack (1) from decreasing.

[0114] In addition, since the first flange portion (324a) of one cell assembly (e.g., 10a) and the second flange portion (324b) of the adjacent cell assembly (e.g., 10b) are arranged in an interleaved manner, the precise assembly position of the cell assembly (10) within the pack housing (20) can be guided, thereby increasing the ease of assembly of the battery pack (1).

[0115] The flow paths (311, 321 of FIGS. 3 to 5) provided in each cell assembly (10) can be connected to refrigerant pipes (24, 25) arranged inside the pack housing (20). The refrigerant pipes (24, 25) can include a refrigerant inlet pipe (24) connected to an inlet port (26) provided on one side of the pack housing (20) and a refrigerant discharge pipe (25) connected to a discharge port (27), and the flow paths (311, 321) of the cell assembly (10) can be connected to the refrigerant inlet pipe (24) and the refrigerant discharge pipe (25), respectively.

[0116] For example, referring to FIG. 6, the cooling member (300) of each cell assembly (10) can be connected to a refrigerant inlet pipe (24) and a refrigerant discharge pipe (25). In this case, the refrigerant inlet pipe (24) and the refrigerant discharge pipe (25) can be connected to either the first opening (313 in FIG. 3) or the second opening (323 in FIG. 3) of the cooling member (300), respectively, so that the refrigerant introduced from the outside of the pack housing (20) can circulate through the flow paths (311, 321) of the cooling member (300) to cool the cell assembly (10) and then be discharged back to the outside of the pack housing (20).

[0117] In the embodiments, the flow paths (311, 321) of the cooling members (300) of each cell assembly (10) can be directly connected to the refrigerant pipes (24, 25). That is, the individual cooling members (300) can be directly supplied with refrigerant from the refrigerant inlet pipe (24), and the refrigerant that has cooled one cell assembly (10) can be directly discharged through the refrigerant discharge pipe (25) without being introduced into the cooling members (300) of other cell assemblies (10). According to this refrigerant supply structure, the refrigerant is directly injected into the cell assemblies (10) from the refrigerant inlet pipe (24), thereby minimizing the cooling difference between the plurality of cell assemblies (10).

[0118] Meanwhile, the arrangement structure of the refrigerant pipes (24, 25) in the pack housing (20) can be implemented in various ways. For example, as shown in FIG. 6, the refrigerant inlet pipe (24) and the refrigerant discharge pipe (25) are arranged along the center line of the pack housing (20), and accordingly, the first opening (313) and the second opening (323) of the cooling member (300) can be opened in the same direction to be connected to the refrigerant pipes (24, 25).

[0119] Alternatively, as shown in FIG. 7, the refrigerant inlet pipe (24) may be arranged along the edge of the pack housing (20), and the refrigerant discharge pipe (25) may be arranged along the center line of the pack housing (20), thereby reducing interference between the refrigerant inlet pipe (24) and the refrigerant discharge 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). Meanwhile, in the embodiments illustrated in FIG. 6 and FIG. 7, other technical features except for the connection structure of the refrigerant pipes (24, 25) and the cooling member (300) are the same.

[0120] In embodiments, the cell assembly (10) can be easily assembled and separated from the pack housing (20) through coupling and disassembly between the cooling member (300) and the cross frame (23). For example, as shown in FIG. 8, the cell assembly (10) is coupled to the pack housing (20) through coupling between the flange portion (324) of the cooling member (300) and the cross frame (23), and an adhesive member (400) may be disposed between the cooling member (300) and the battery cell (110), but a separate adhesive member may not be disposed between the cooling member (300) and the pack housing (20). Therefore, compared to a conventional battery pack structure in which a battery cell (or a cell assembly including a battery cell) and a pack housing are coupled via an adhesive member interposed therebetween, the cell assembly (10) can be easily separated from the pack housing (20). In particular, with this type of combined structure, only some cell assemblies that have problems during the manufacturing process or use of the battery pack (1) can be easily separated and replaced, so that the efficiency and maintainability of the manufacturing process of the battery pack (1) can be increased.

[0121] In addition, a wide joint surface with the cross frame (23) is secured through the flange portion (324) protruding from the side plate (320) of the cooling member (300), so that 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).

[0122] In addition, the side plate (320) of the cooling member (300) acts as a buffer structure between the cross frame (23) and the cell stack (100), thereby preventing excessively strong surface pressure from being applied to the cell stack (100), and appropriately absorbing the expansion pressure due to the swelling phenomenon, so that an increase in the lifespan of the battery cell (110) can be expected.

[0123] In addition, each cell assembly (10) has an individual cooling path, so that a battery pack (1) with excellent cooling performance and a small cooling difference between multiple cell assemblies (10) can be implemented.

[0124] While 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 apparent to those skilled in the art that various modifications and variations are possible without departing from the technical spirit of the present invention as set forth in the claims. Furthermore, the embodiments described above may be implemented by deleting some components, and the embodiments may be implemented in combination with each other.

[0125] [Explanation of symbols]

[0126] 1... Battery Pack 10... Cell Assembly

[0127] 20... Pack housing 21... Lower frame

[0128] 22... Side frame 23... Cross frame

[0129] 100... cell stack 110... battery cells

[0130] 200... Busbar assembly 300... Cooling member

[0131] 310... Base plate 311... 1st Euro section

[0132] 320... Side plate 321... Second Euro section

[0133] 322... Hollow section 324a... First flange section

[0134] 324b... 2nd flange part 400... adhesive member

Claims

1. A plurality of cell assemblies, each including a cell stack having a plurality of battery cells stacked thereon and a cooling member surrounding at least one surface of the cell stack; and A pack housing is included in which the plurality of cell assemblies are accommodated, The above cooling member A base plate positioned facing the lower surface of the above cell stack; At least one side plate, which is arranged facing the stacking direction of the cell stack and the plurality of battery cells, and is coupled to the pack housing; and A battery pack including a flow path formed across the base plate and one or more side plates and configured to allow coolant to flow therein.

2. In paragraph 1, The above pack housing a lower frame on which the above plurality of cell assemblies are mounted; and It comprises one or more cross frames arranged on the above lower frame and dividing the internal space of the pack housing, A battery pack wherein said one or more side plates are coupled to said one or more cross frames.

3. In paragraph 2, One or more of the above side plates A first side plate covering one side of the cell stack and having a plurality of first flange portions spaced apart along the length direction of the cross frame; and A battery pack including a second side plate covering the opposite side of the cell stack and having a plurality of second flange portions spaced apart along the longitudinal direction of the cross frame.

4. In paragraph 3, A battery pack in which the plurality of first flange portions and the plurality of second flange portions are mounted and joined on the upper portion of one or more cross frames.

5. In paragraph 3, A battery pack 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. In paragraph 3, The above plurality of cell assemblies include a first cell assembly and a second cell assembly adjacent to each other with the cross frame interposed therebetween, A battery pack wherein at least one of the plurality of first flange portions of the first cell assembly is disposed between the plurality of second flange portions of the second cell assembly.

7. In paragraph 6, A battery pack in which, 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 alternately arranged along the longitudinal direction of the cross frame.

8. In paragraph 3, A battery pack 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 is fastened to the pack housing.

9. In paragraph 3, The above Euro part A first flow path section arranged inside the base plate and configured to allow the refrigerant to flow; and A battery pack comprising a second section positioned inside one or more of the side plates and communicating with the first section.

10. In paragraph 9, The above base plate includes a first opening connected to the first euro portion, The one or more side plates include a second opening connected to the second euro portion, A battery pack wherein one of the first opening and the second opening is connected to a coolant inlet pipe arranged inside the pack housing, and the other is connected to a coolant discharge pipe arranged inside the pack housing.

11. In clause 10, A battery pack wherein the refrigerant portion of each of the above multiple cell assemblies is directly connected to the refrigerant inlet pipe and the refrigerant discharge pipe.

12. In paragraph 10, The first Eurozone A branch point, which is the starting point from which one of the channels connecting to the first opening branches off; and It includes a first sub-euro section and a second sub-euro section branched by the above branch section, A battery pack, wherein one of the first sub-Euro section and the second sub-Euro section is connected to the second Euro section of the first side plate, and the other is connected to the second Euro section of the second side plate.

13. In paragraph 9, The one or more side plates further include one or more hollow portions separated from the second euro portion, A battery pack having one or more hollow portions having an air gap formed inside.

14. In paragraph 13, A battery pack in which the one or more hollow portions are provided in plurality inside the one or more side plates, and the second euro portion is disposed between the plurality of hollow portions.

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