Rechargeable battery pack

Abstract

A rechargeable battery pack includes: a cell stack including a plurality of battery cells stacked in a first direction; the central frame comprises a first bottom plate and a first side wall which are integrally formed and supports the single body stack; and a first side frame and a second side frame each including a second bottom plate and a second side wall integrally formed, the second bottom plate coupled to the first bottom plate in a second direction crossing the first direction, the second side wall supporting a narrow cell side surface of the cell stack. The first bottom plate and the second bottom plate include a plurality of cooling water paths extending in the first direction and spaced apart from each other in the second direction.

Description

Technical Field

[0001] Aspects of embodiments of the present disclosure relate to a rechargeable battery pack. Background Art

[0002] Unlike primary batteries, rechargeable batteries are designed to be repeatedly charged and discharged. Small-capacity rechargeable batteries are used in small portable electronic devices such as mobile phones, laptop computers, and portable video cameras. Rechargeable batteries with large capacity and high density are used as power sources for driving motors in hybrid vehicles and electric vehicles or for energy storage.

[0003] The rechargeable battery can be used as (or implemented as) a rechargeable battery module, which includes a plurality of battery cells connected in series and / or in parallel to drive a motor that requires a relatively high energy density, such as a hybrid vehicle. To implement a relatively high-power rechargeable battery module (e.g., for an electric vehicle), a plurality of rechargeable battery cells provided in a certain number and connected in a configuration that provides a required amount of electric power are stacked in a frame to form a rechargeable battery module.

[0004] These rechargeable battery modules are connected in series and / or in parallel within a housing manufactured by using various methods to form a rechargeable battery pack. Accordingly, various types of rechargeable battery modules are being produced to provide rechargeable battery packs with various capacities.

[0005] In terms of energy capacity, the battery pack including the rechargeable battery module has limitations. A rechargeable battery pack that directly assembles battery cells without a rechargeable battery module can increase or maximize the energy density of the rechargeable battery pack. In addition, it is desirable to simplify the structures of the frame and the cooling part, enhance the stiffness of the frame and the cooling part, and reduce the weight of the frame and the cooling part. Summary of the Utility Model

[0006] Embodiments of the present disclosure provide a rechargeable battery pack that simplifies the structures of the frame and the cooling part, enhances the stiffness of the frame and the cooling part, and reduces the weight of the frame and the cooling part. In addition, the embodiments provide a rechargeable battery pack that increases or maximizes the energy density of the battery pack by stacking battery cells.

[0007] A rechargeable battery pack according to an embodiment of the present disclosure includes: a cell stack including a plurality of battery cells stacked in a first direction; a center frame including an integrally formed first bottom plate and a first side wall and supporting the cell stack; and a first side frame and a second side frame, each including an integrally formed second bottom plate and a second side wall, the second bottom plate being coupled to the first bottom plate in a second direction intersecting the first direction, and the second side wall supporting a narrow cell side surface of the cell stack. The first bottom plate and the second bottom plate include a plurality of cooling water paths extending in the first direction and spaced apart from each other in the second direction.

[0008] The first bottom plate and the second bottom plate may include: an inflow balancer connecting inlets of the cooling water paths to balance an inflowing cooling water flow; an outflow balancer connecting outlets of the cooling water paths to balance an outflowing cooling water flow; and a reflux portion connecting the cooling water paths on a reflux side of the cooling water paths to form a balance of cooling water reflux.

[0009] The inflow balancer may connect inflow balance channels together at a final inlet, each of the inflow balance channels being connected to the inlet of the cooling water path, and the outflow balancer may connect outflow balance channels together at a final outlet, each of the outflow balance channels being connected to the outlet of the cooling water path.

[0010] The reflux portion may include: a first reflux line connecting the outlet and the inlet of the cooling water path in the first bottom plate; and a second reflux line connecting the outlet and the inlet of the cooling water path in the second bottom plate

[0011] The first reflux line may have a plurality of reflux holes and may be a first reflux pipe welded to the first bottom plate and connected to the cooling water path through a rubber seal.

[0012] The second reflux line may be provided on one side of the first reflux pipe in the first direction, may have a plurality of reflux holes, and may be a second reflux pipe welded to the second bottom plate and connected to the cooling water path through a rubber seal.

[0013] The inflow balance channels of the inflow balancer may be connected to the cooling water path in the second bottom plate of the first side frame and to half of the cooling water path in the first bottom plate of the center frame, and the outflow balance channels of the outflow balancer may be connected to the cooling water path in the second bottom plate of the second side frame and to the remaining half of the cooling water path in the first bottom plate of the center frame.

[0014] The inflow balance channels of the inflow balancer may form a symmetric structure in the second direction.

[0015] The outflow balance channels of the outflow balancer may form a symmetric structure in the second direction.

[0016] The inflow balance channels of the inflow balancer may have lengths that respectively gradually decrease or increase from the outside toward the center in the second direction.

[0017] The outflow balance channels of the outflow balancer may have lengths that respectively gradually decrease or increase from the outside toward the center in the second direction.

[0018] The first bottom plate and the second bottom plate may be welded at a welding bottom surface having a first width, a welding top surface having a second width larger than the first width, and a welding inclined surface connecting the welding bottom surface and the welding top surface.

[0019] The first bottom plate and the second bottom plate may be connected by coupling coupling protrusions and coupling grooves formed along the first direction.

[0020] The coupling protrusions and the coupling grooves may be fixed by welding in the coupled state.

[0021] The first bottom plate may have a narrow lower surface and a wide upper surface such that the side surface of the first bottom plate slopes downward, the second bottom plate may have a wide lower surface and a narrow upper surface such that the side surface of the second bottom plate slopes upward, and the downward-sloping side surface of the first bottom plate may be coupled to the upward-sloping side surface of the second bottom plate on the opposite side of the first bottom plate in the second direction.

[0022] The rechargeable battery pack may further include a first end frame and a second end frame, which are respectively coupled to opposite ends of the center frame, the first side frame, and the second side frame in the first direction to support the wide cell side surfaces of the cell stack.

[0023] The rechargeable battery pack according to the embodiment integrally forms the center frame and the first and second side frames, and includes a plurality of cooling water paths in the first bottom plate and the second bottom plate, thereby simplifying the structures of the frame and the cooling part, enhancing the stiffness of the frame and the cooling part, and reducing the weight of the frame and the cooling part.

[0024] In addition, according to the embodiment, a cell stack including a plurality of battery cells stacked in the first direction is provided between the first end frame and the second end frame, and thus, the energy density of the battery pack can be increased or maximized. Description of the Drawings

[0025] Figure 1 is a perspective view of a rechargeable battery pack according to one embodiment.

[0026] Figure 2 is Figure 1 an exploded perspective view of a cell frame of the rechargeable battery pack shown in

[0027] Figure 3 is a perspective view of a cell stack in which Figure 1 the battery cells shown in

[0028] Figure 4 are stacked. Figure 2 is a sectional view taken along line IV-IV of

[0029] Figure 5 is Figure 2 a sectional view of the cell frame after being joined together, taken along line V-V of

[0030] Figure 6 is a sectional view of a cell frame coupling part according to another embodiment.

[0031] Figure 7 is a schematic view of a cell frame coupling part according to another embodiment.

[0032] Figure 8 is Figure 1 and Figure 2 a plan view from above of a cooling water path formed in the cell frame shown in

[0033] Figure 9 is Figure 5 a perspective view of a flow balancer applied to an inlet and an outlet of a cooling water path formed in the cell frame shown in

[0034] Figure 10 is a plan view from above of a flow balancer according to another embodiment.

[0035] Figure 11 is a plan view from above of a flow balancer according to another embodiment.

[0036] Figure 12 is Figure 9 a plan view from above of a flow balancer shown in

[0037] Figure 13 installed on an inlet and / or an outlet side of a path formed in the cell frame. Figure 8 is an exploded perspective view of a return part of the cooling water path shown in

[0038] Figure 14 is Figure 13 an enlarged exploded perspective view of a part of

[0039] Figure 15 is Figure 13 an enlarged top plan view of a part of

[0040] Figure 16 is an image of the computer-aided engineering (CAE) analysis result when using a flow balancer.

[0041] Figure 17 is a graph depicting the flow distribution at the inlet region of each cooling channel when using a flow balancer.

[0042] Figure 18 is a graph depicting the flow distribution at the outlet region of each cooling channel when using a flow balancer.

[0043] Figure 19 is a graph depicting the improvement of the crushing characteristics in the x-axis direction as a CAE analysis result when applying the structure integrating the frame and the cooling water path according to an embodiment.

[0044] Figure 20 is a graph depicting the crushing characteristics in the x-axis direction as a CAE analysis result when applying the structure in which the frame and the cooling water path are not integrated according to the comparative example. DETAILED DESCRIPTION

[0045] Hereinafter, the present disclosure will be described more fully with reference to the accompanying drawings showing embodiments of the present disclosure. As will be appreciated by those skilled in the art, the described embodiments may be modified in various different ways, all of which do not depart from the spirit or scope of the present disclosure. The drawings and the description are to be regarded as illustrative in nature and not restrictive.

[0046] It will be understood that when an element or layer is referred to as being "on", "connected to" or "coupled to" another element or layer, it can be directly on, connected or coupled to the other element or layer, or there may also be one or more intervening elements or layers. When an element or layer is referred to as being "directly on", "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers. For example, when the first element is described as being "coupled" or "connected" to the second element, the first element can be directly coupled or connected to the second element, or the first element can be indirectly coupled or connected to the second element via one or more intervening elements.

[0047] In the figures, for clarity of illustration, the sizes of various elements, layers, etc. may be enlarged. The same reference numerals denote the same elements. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Additionally, as used in describing embodiments of the present disclosure, "may" refers to "one or more embodiments of the present disclosure". Expressions such as "at least one of" and "any one of", when following a list of elements, modify the entire list of elements and not a single element in the list. For example, the expression "at least one of a, b, and c" means only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c, or variations thereof. As used herein, the term "use" may be considered synonymous with the term "utilize". As used herein, the terms "substantially", "about", and similar terms are used as approximate terms and not as terms of degree, and are intended to account for the inherent variations in measured or calculated values that would be recognized by a person of ordinary skill in the art.

[0048] It will be understood that although the terms "first", "second", "third", etc. may be used herein to describe various elements, components, regions, layers, and / or sections, these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, without departing from the teachings of the exemplary embodiments, the first element, component, region, layer, or section discussed below may be referred to as the second element, component, region, layer, or section.

[0049] For ease of description, spatial relative terms such as "beneath", "below", "lower", "above", "upper", etc. may be used herein to describe the relationship of one element or feature to another element or feature as illustrated in the figures. It will be understood that these spatial relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is flipped, an element described as "below" or "beneath" another element or feature will then be oriented "above" or "over" the other element or feature. Thus, the term "below" can encompass both an upper and a lower orientation. The device may be oriented in other ways (rotated 90 degrees or at other orientations), and the spatial relative descriptors used herein should be interpreted accordingly.

[0050] The terms used herein are for the purpose of describing embodiments of the present disclosure and are not intended to limit the present disclosure. As used herein, the singular form "a" is also intended to include the plural form unless the context clearly dictates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0051] Figure 1 is a perspective view of a rechargeable battery pack according to an embodiment, and Figure 2 is Figure 1 an exploded perspective view of the pack frame of the rechargeable battery pack shown in. Refer to Figure 1 and Figure 2 , a rechargeable battery pack according to an embodiment includes a plurality of cell stacks 100 and a pack frame 200 in which the cell stacks 100 are mounted.

[0052] The pack frame 200 includes a center frame 10, a first side frame 21, a second side frame 22, a first end frame 31, and a second end frame 32. When the length of the pack frame 200 is long in a first direction (e.g., the x-axis direction), the pack frame 200 may further include a cross center frame 40.

[0053] The cross center frame 40 is joined to the center frame 10 and the first and second side frames 21 and 22 at the middle in the first direction (e.g., the x-axis direction) to support the wide cell side surfaces on both sides in the first direction of different cell stacks 100.

[0054] The center frame 10 and the first and second side frames 21 and 22 are extruded and cut, and thus, they can accommodate various sizes of cell stacks 100 according to the length in the first direction (e.g., the x-axis direction). For example, the center frame 10, the first side frame 21, and the second side frame 22 may be cut to appropriate lengths according to the length of the cell stack 100 in the first direction and then joined to form the pack frame 200.

[0055] In the pack frame 200, the center frame 10, the first side frame 21, and the second side frame 22 are formed using an extruded profile structure, and thus, an assembly space for the cell stacks 100 can be easily formed.

[0056] The cross-sectional structure of the extruded profile and the length variation of the center frame 10 and the first and second side frames 21 and 22 can allow for easy adjustment (e.g., size or length adjustment) in response to various energy sizes designed for various cell stack sizes of an electric vehicle.

[0057] The central frame 10 includes a first bottom plate 11 and a first side wall 12 integrally formed and supports the monomer stack 100. The first side wall 12 is formed long in a first direction (e.g., the x-axis direction) (e.g., mainly extending in the first direction) and has a height from the center of the first bottom plate 11 in a second direction (e.g., the y-axis direction) to a third direction (e.g., the z-axis direction). Thus, there are no side walls at both ends of the central frame 10 in the second direction (e.g., the y-axis direction) to form an open first bottom plate 11.

[0058] The first side frame 21 and the second side frame 22 are coupled to the central frame 10 in a second direction (e.g., the y-axis direction) that intersects (e.g., intersects) the first direction (e.g., the x-axis direction). The first side frame 21 and the second side frame 22 each include a second bottom plate 211, 221 and a second side wall 212, 222 integrally formed, and the second side walls 212, 222 support the narrow monomer side surfaces of the monomer stack 100 (e.g., in the x-z plane). The second bottom plates 211, 221 are coupled to both sides (e.g., opposite sides) of the first bottom plate 11 in the second direction.

[0059] The first end frame 31 and the second end frame 32 are coupled to opposite ends of the central frame 10 and the first side frame 21 and the second side frame 22 in a first direction (e.g., the x-axis direction) to support the wide monomer side surfaces (e.g., in the y-z plane) and provide (or form) the cooling water inlet side and the outlet side of the monomer stack 100.

[0060] Figure 3 is a perspective view of a monomer stack in which Figure 1 the battery monomers shown in Figure 1 and Figure 3 are stacked. The monomer stack 100 is formed by stacking a plurality of battery monomers 101 in a first direction (e.g., the x-axis direction).

[0061] Before being installed in the group frame 200, the monomer stack 100 holds the battery monomers 101 in a stacked state in a space formed (or formed between) by a pair of side housings 110 spaced apart from each other in a second direction and a pair of end housings 120 spaced apart from each other in a first direction. The battery monomers 101 may be rectangular rechargeable batteries having wide monomer side surfaces (e.g., in the y-z plane) and narrow monomer side surfaces (e.g., in the x-z plane) and having electrode terminals 102, 103 on the top side.

[0062] In the battery cell 101, the wide cell side surfaces face both sides of the battery cell 101 in the first direction (e.g., the x-axis direction), and the narrow cell side surfaces face both sides of the battery cell 101 in the second direction (e.g., the y-axis direction) that intersects the first direction. The electrode terminals 102, 103 are oriented upward (or face upward or extend upward) in the third direction (e.g., the z-axis direction) that is orthogonal to the first direction and the second direction (e.g., the x-axis direction and the y-axis direction).

[0063] Figure 4 is a cross-sectional view taken along line IV-IV Figure 2 . Refer to Figure 2 and Figure 4 , the first side frame 21 and the second side frame 22 integrally form the second bottom plates 211, 221 and the second side walls 212, 222, and the center frame 10 integrally forms the first bottom plate 11 and the first side wall 12.

[0064] The second bottom plate 221 has a plurality of cooling water paths 50 that extend in the first direction (e.g., the x-axis direction) and are spaced apart from each other in the second direction (e.g., the y-axis direction) and are configured to cool the water that will flow therethrough. The cooling water paths 50 have the same structure in the second bottom plates 211, 221 of the first side frame 21 and the second side frame 22 and in the first bottom plate 11 of the center frame 10. Therefore, only the cooling water paths 50 in the second side frame 22 are illustrated as an example. In Figure 8 , the entire configuration of the cooling water paths 50 is schematically illustrated.

[0065] When the first bottom plate 11 and the second bottom plates 211, 221 are provided with the cooling water paths 50, the cooling portion including the cooling water paths 50 is integrally formed with the first bottom plate 11 and the second bottom plates 211, 221. Accordingly, the cooling portion is integrally formed with the group frame 200. In such an embodiment, the structure of the cooling portion is simplified, the stiffness of the group frame 200 and the cooling portion is enhanced, and the group frame 200 and the cooling portion can be made lighter.

[0066] Hereinafter, the bonding and connection structure between the first bottom plate 11 and the second bottom plates 211, 221 will be described in more detail. Figure 5 is a cross-sectional view of the group frame after connection (e.g., in the non-disassembled state) taken along line V-V Figure 2 . Refer to Figure 5, in the central frame 10 and the second side frame 22, for example, the first bottom plate 11 and the second bottom plate 221 are welded using a welding bottom surface having a first width W1, a welding top surface having a second width W2 larger than the first width W1, and a welding inclined surface connecting the bottom surface and the top surface (or extending therebetween). The welded portion W may form a downward wedge structure to enhance the welding bond strength between the first bottom plate 11 and the second bottom plate 221.

[0067] Figure 6 is a cross-sectional view of a group frame coupling portion according to another embodiment. Refer to Figure 6 , for example, in the central frame 610 and the second side frame 62, the first bottom plate 611 and the second bottom plate 621 are extruded, and thus, they are connected by coupling the coupling protrusions 63 and the coupling grooves 64 formed along a first direction (e.g., the x-axis direction). In addition, the coupling protrusions 63 and the coupling grooves 64 are further fixed by welding WP while being in a coupled state, thereby being able to prevent relative movement in the first direction and the second direction. The welding WP may be spot welding at regular intervals (e.g., a predetermined interval or a repeating interval) along the first direction.

[0068] Figure 7 is a schematic view of a group frame coupling portion according to another embodiment. Refer to Figure 7 , the first bottom plate 711 of the central frame 710 has a relatively narrow lower surface and a relatively wide upper surface, and thus, its side surface slopes downward. The second bottom plates 731 of the first side frame 73 and 741 of the second side frame 74 have relatively wide lower surfaces and relatively narrow upper surfaces, and thus, their side surfaces slope upward.

[0069] The downward-sloping side surface of the first bottom plate 711 is coupled to the upward-sloping side surfaces of the second bottom plates 731 and 741 provided on opposite sides of the first bottom plate 711 in a second direction (e.g., the y-axis direction). Since the upward-sloping side surfaces of the second bottom plates 731 and 741 support the downward-sloping side surface of the first bottom plate 711, the bonding strength between the first bottom plate 711 and the second bottom plates 731 and 741 can be stabilized, and when using spot welding, the bonding strength can be further enhanced.

[0070] Hereinafter, the cooling portions of the first bottom plate 11 and the second bottom plates 211 and 221 will be described in more detail. Figure 8 is formed in Figure 1 and Figure 2 is a top plan view of a cooling water path in the group frame shown in. Refer to Figure 8 , the first bottom plate 11 and the second bottom plates 211 and 221 include an inflow balancer 41, an outflow balancer 42, and a return portion 43 connected to the cooling water path 50.

[0071] The inflow balancer 41 is configured to connect to the inlet of the cooling water path 50 so as to balance (e.g., distribute) the inflowing cooling water. The outflow balancer 42 is configured to connect to the outlet of the cooling water path 50 so as to balance (e.g., collect) the outflowing cooling water. The return portion 43 is configured to connect to the cooling water path 50 on the return side of the cooling water path 50 so as to form a balance of the cooling water return.

[0072] The inflow balancer 41 connects a final inlet 412 to the inflow balance channels 411 that are respectively connected to the inlet of the cooling water path 50. The outflow balancer 42 connects the outflow balance channels 421 that are respectively connected to the outlet of the cooling water path 50 to a final outlet 422.

[0073] The return portion 43 includes a first return line 431 and a second return line 432. The first return line 431 connects the outlet and the inlet formed in the first bottom plate 11 of the cooling water path 50 to each other. The second return line 432 connects the outlets and inlets on the return side formed in the second bottom plates 211 of the first side frame 21 and 221 of the second side frame 22 of the cooling water path 50.

[0074] Figure 13 is Figure 8 an exploded perspective view of the return portion of the cooling water path shown in Figure 14 is Figure 13 an enlarged exploded perspective view of a part of Figure 15 is Figure 13 an enlarged top plan view of the coupling portion in a part of

[0075] Reference Figures 13 to 15 , the first return line 431 has a plurality of return holes (e.g., return openings) H1 and is formed as a first return pipe 431 that is connected to the cooling water path 50 through a rubber seal S1 and welded to the first bottom plate 11.

[0076] The second return line 432 is provided on one side of the first return pipe 431 in a first direction (e.g., the x-axis direction), has a plurality of return holes (e.g., return openings) H2, and is formed as a second return pipe 432 that is connected to the cooling water path 50 through a rubber seal S2 and welded to the second bottom plates 211, 221.

[0077] For ease of description, the same reference numerals are assigned to the first return line 431 and the second return line 432 and the first return pipe 431 and the second return pipe 432. The first return pipe 431 and the second return pipe 432 are welded to the first bottom plate 11 and the second bottom plates 211, 221. In such an embodiment, the seals S1, S2 are compressed to seal the connection between the cooling water path 50 and the return holes H1, H2.

[0078] As an example, when the central frame 10 and the first side frame 21 and the second side frame 22 are extruded aluminum, the first return pipe 431 and the second return pipe 432 are formed of aluminum pipes to improve the welding performance.

[0079] Return reference Figure 8 , the inflow balance passage 411 of the inflow balancer 41 is connected to the cooling water path 50 in the second bottom plate 211 of the first side frame 21 and is connected to half of the cooling water path 50 in the first bottom plate 11 of the central frame 10.

[0080] The outflow balance passage 421 of the outflow balancer 42 is connected to the cooling water path 50 in the second bottom plate 221 of the second side frame 22 and is connected to the remaining half of the cooling water path 50 in the first bottom plate 11 of the central frame 10.

[0081] As Figure 8 shown, the inflow balance passage 411 of the inflow balancer 41 and the outflow balance passage 421 of the outflow balancer 42 can be formed to have the same structure.

[0082] Figure 9 is a perspective view of a flow balancer applied to the inlets and outlets of the cooling water paths in the group frame shown in Figure 5 . Referring to Figure 9 , the inflow balance passage 411 of the inflow balancer 41 is formed in a symmetric structure in the second direction (e.g., the y-axis direction) and is connected integrally (e.g., connected together) at the final inlet 412. Low-temperature cooling water flows into the final inlet 412.

[0083] The outflow balance passage 421 of the outflow balancer 42 is formed in a symmetric structure in the second direction (e.g., the y-axis direction) and is connected integrally (e.g., connected together) at the final outlet 422. High-temperature cooling water flows out through the final outlet 422.

[0084] Therefore, the low-temperature cooling water flowing into the inflow balancer 41 is first heated via the cooling water path 50 and is secondarily heated via the first return line 431 and the second return line 432 and the cooling water path 50. The heated high-temperature cooling water flows out through the outflow balancer 42.

[0085] Figure 10 is a top plan view of a flow balancer according to another embodiment. Referring to Figure 10, the inflow balance passage 451 of the inflow balancer 45 may have a passage length that gradually shortens or lengthens from the outside toward the center in the second direction (e.g., the y-axis direction). The passage length of the outflow balance passage 461 of the outflow balancer 46 may gradually shorten or lengthen from the outside toward the center in the second direction (e.g., the y-axis direction). The inflow balance passage 451 and the outflow balance passage 461 may have the same width or may have widths of substantially similar dimensions.

[0086] Figure 11 is a top plan view of a flow balancer according to another embodiment. Refer to Figure 11 , the inflow balance passage 471 of the inflow balancer 47 may have a passage length that gradually shortens or lengthens from the outside toward the center in the second direction (e.g., the y-axis direction). The passage length of the outflow balance passage 481 of the outflow balancer 48 may gradually shorten or lengthen from the outside toward the center in the second direction (e.g., the y-axis direction). The inflow balance passage 471 and the outflow balance passage 481 may be formed to have a relatively large width on the side of the cooling water path 50 and a relatively narrow width on the side of the final inlet 412 or the final outlet 422.

[0087] Figure 12 is Figure 9 a top plan view of the state in which the flow balancer shown in Figure 12 , the inflow balancer 41 is installed on one side of the first side frame 21 and the center frame 10 and is assembled thereto by welding, and a sealing structure is formed on the lower surfaces of the second bottom plate 211 and the first bottom plate 11 by using a sealing member S41 provided between the second bottom plate 211 and the first bottom plate 11. In such an embodiment, the inflow balance passage 411 is connected to the cooling water path 50.

[0088] The outflow balancer 42 is installed on one side of the second side frame 22 and the center frame 10 and is assembled thereto by welding, and a sealing structure is formed on the lower surfaces of the second bottom plate 211 and the first bottom plate 11 by using a sealing member S42 provided between the second bottom plate 211 and the first bottom plate 11. In such an embodiment, the outflow balance passage 421 is connected to the cooling water path 50.

[0089] Figure 16 is an image of the computer-aided engineering (CAE) analysis result when using the flow balancer. Specifically, Figure 16 the image of Figure 10 shows the CAE analysis result when using the inflow balancer 45 and the outflow balancer 46 shown in

[0090] As Figure 16As seen, a similar temperature distribution appears in the inflow balancer 45 and the outflow balancer 46, and a symmetric temperature distribution appears in the second direction (e.g., the y-axis direction). Also, a similar temperature distribution appears in the cooling water path 50 connected to the inflow balancer 45 and the cooling water path 50 connected to the outflow balancer 46, and a symmetric temperature distribution appears in the second direction (e.g., the y-axis direction).

[0091] Figure 17 is a diagram depicting the flow rate distribution in the inlet region of each cooling channel when using a flow rate balancer, and Figure 18 is a diagram depicting the flow rate distribution in the outlet region of each cooling channel when using a flow rate balancer.

[0092] Reference Figure 17 and Figure 18 to achieve a similar flow rate distribution among the inflow balance channels 451 of the inflow balancer 45, and to achieve a similar flow rate distribution among the outflow balance channels 461 of the outflow balancer 46.

[0093] Furthermore, the flow rate distribution of the inflow balancer 45 and the flow rate distribution of the outflow balancer 46 are symmetric with each other in the second direction (e.g., the y-axis direction). In addition, a symmetric temperature distribution appears in the first return line 431 and the second return line 432 in the second direction (e.g., the y-axis direction).

[0094] Figure 19 is a diagram depicting the improvement of the crushing characteristics in the x-axis direction as a result of CAE analysis in a structure where a frame and a cooling water path are integrated according to an embodiment of the present disclosure, and Figure 20 is a diagram depicting the crushing characteristics in the x-axis direction as a result of CAE analysis when applying a structure where a frame and a cooling water path are not integrated according to a comparative example.

[0095] In the group frame 200, according to an embodiment, the cooling water path 50 is integrally formed in the first bottom plate 11 and the second bottom plates 211, 221, and the inflow balancer 45, the outflow balancer 46, the first return pipe 431, and the second return pipe 432 are connected to the cooling water path 50.

[0096] As Figure 19 seen, compared with the comparative example where the cooling part is formed separately, the x-axis direction crushing characteristics of the rechargeable battery pack according to the embodiment where the cooling part is integrally formed in the group frame are improved.

[0097] In the comparative example (see Figure 20 ), the group frame is crushed under a reaction force of 80 to 100 kN. In contrast, referring to Figure 19, the displacement of the battery pack frame 200 is 4 mm under a reaction force of 100 kN, and the displacement of the battery pack frame 200 is 23 mm under a reaction force of 200 kN.

[0098] A rechargeable battery pack according to an embodiment may further include a battery pack cover mounted on the first side frame 21, the second side frame 22, the first end frame 31, and the second end frame 32. The battery pack cover covers a bus bar that electrically connects the electrode terminals 102, 103 of the battery cells 101.

[0099] Return to reference Figure 1 and Figure 2 , in the battery pack frame 200, the first side frame 21 and the second side frame 22 are formed long along the first direction (e.g., the x-axis direction) on the outer sides of the battery pack frame 200 in the second direction (e.g., the y-axis direction), and can be mounted on a vehicle through flanges as fastening members.

[0100] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited thereto, and various modifications can be made and implemented within the scope of the claims and their equivalents, the detailed description, and the drawings, all of which fall within the scope of the present disclosure.

[0101] Explanation of some reference numerals:

[0102] 10: Central frame 11: First bottom plate

[0103] 12: First side wall 21: First side frame

[0104] 22: Second side frame 31: First end frame

[0105] 32: Second end frame 40: Cross central frame

[0106] 41: Inflow balancer 42: Outflow balancer

[0107] 43: Return part 45, 47: Inflow balancers

[0108] 46, 48: Outflow balancers 50: Cooling water path

[0109] 63: Coupling protrusion 64: Coupling groove

[0110] 73, 74: First side frame, second side frame 100: Cell stack

[0111] 101: Battery cell 102, 103: Electrode terminals

[0112] 200: Battery pack frame 211, 221: Second bottom plates

[0113] 212, 222: Second side walls 411: Inflow balance channel

[0114] 412: Final inlet 421: Outflow balance channel

[0115] 422: Final outlet 431: First reflux line (pipe)

[0116] 432: Second reflux line (pipe) 451, 471: Inflow balance channel

[0117] 461, 481: Outflow balance channel 610: Central frame

[0118] 611: First bottom plate 621: Second bottom plate

[0119] 710: Central frame 711: First bottom plate

[0120] 731, 741: Second bottom plate H1, H2: Reflux holes

[0121] S1, S2: Rubber seals S41, S42: Sealing members

[0122] W: Welded part W1: First width

[0123] W2: Second width WP: Welding

Claims

1. A rechargeable battery pack, characterized in that, Comprising: A monomer stack including a plurality of battery monomers stacked in a first direction; A central frame including an integrally formed first bottom plate and a first side wall and supporting the monomer stack; And A first side frame and a second side frame, each including an integrally formed second bottom plate and a second side wall, the second bottom plate being connected to the first bottom plate in a second direction intersecting the first direction, and the second side wall supporting a narrow monomer side surface of the monomer stack, Wherein the first bottom plate and the second bottom plate include a plurality of cooling water paths extending in the first direction and spaced apart from each other in the second direction.

2. The rechargeable battery pack according to claim 1, wherein The first bottom plate and the second bottom plate include: An inflow balancer connecting the inlets of the cooling water paths to balance the inflowing cooling water flow; An outflow balancer connecting the outlets of the cooling water paths to balance the outflowing cooling water flow; and A reflux portion connecting the cooling water paths on the reflux side of the cooling water paths to form a balance of the cooling water reflux.

3. The rechargeable battery pack according to claim 2, characterized in that, The inflow balancer connects the inflow balance channels together at a final inlet, each of the inflow balance channels being connected to the inlet of the cooling water path, and Wherein the outflow balancer connects the outflow balance channels together at a final outlet, each of the outflow balance channels being connected to the outlet of the cooling water path.

4. The rechargeable battery pack according to claim 3, characterized in that, The reflux portion includes: A first reflux line connecting the outlet and the inlet formed in the first bottom plate of the cooling water path; and A second reflux line connecting the outlet and the inlet formed in the second bottom plate of the cooling water path.

5. The rechargeable battery pack according to claim 4, characterized in that, The first reflux line has a plurality of reflux holes and is a first reflux pipe welded to the first bottom plate and connected to the cooling water path through a rubber seal.

6. The rechargeable battery pack according to claim 5, wherein, The second reflux line is on one side of the first reflux pipe in the first direction, has a plurality of reflux holes, and is a second reflux pipe connected to the cooling water path through a rubber seal and welded to the second bottom plate.

7. The rechargeable battery pack according to claim 3, characterized in that, The inflow balance channels of the inflow balancer are connected to the cooling water paths in the second bottom plate of the first side frame and half of the cooling water paths in the first bottom plate of the central frame, and Wherein the outflow balance channels of the outflow balancer are connected to the cooling water paths in the second bottom plate of the second side frame and the remaining half of the cooling water paths in the first bottom plate of the central frame.

8. The rechargeable battery pack according to claim 7, wherein The inflow balance channels of the inflow balancer form a symmetric structure in the second direction.

9. The rechargeable battery pack according to claim 7, wherein, The outflow balance channels of the outflow balancer form a symmetric structure in the second direction.

10. The rechargeable battery pack according to claim 7, characterized in that, The inflow balance channels of the inflow balancer have lengths that gradually decrease or increase from the outside toward the center in the second direction respectively.

11. The rechargeable battery pack according to claim 7, characterized in that, The outflow balance channels of the outflow balancer have lengths that gradually decrease or increase from the outside toward the center in the second direction respectively.

12. The rechargeable battery pack according to claim 1, wherein The first bottom plate and the second bottom plate are welded to form a welded bottom surface having a first width, a welded top surface having a second width greater than the first width, and a welded inclined surface connecting the welded bottom surface and the welded top surface.

13. The rechargeable battery pack according to claim 1, characterized in that, The first bottom plate and the second bottom plate are connected by coupling coupling protrusions and coupling grooves formed along the first direction.

14. The rechargeable battery pack according to claim 13, characterized in that, The coupling protrusions and the coupling grooves are fixed by welding in the coupled state.

15. The rechargeable battery pack according to claim 1, characterized in that, The first bottom plate has a narrow lower surface and a wide upper surface, such that the side surface of the first bottom plate slopes downward, wherein the second bottom plate has a wide lower surface and a narrow upper surface, such that the side surface of the second bottom plate slopes upward, and wherein the downward-sloping side surface of the first bottom plate is coupled to the upward-sloping side surface of the second bottom plate on the opposite side of the first bottom plate in the second direction.

16. The rechargeable battery pack according to claim 1, wherein, Further comprising a first end frame and a second end frame, respectively coupled to opposite ends of the central frame, the first side frame, and the second side frame in the first direction to support the wide monomer side surface of the monomer stack.

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