Battery module and method for assembling the same

Abstract

The method for assembling a battery module according to the present invention comprises: a sub-frame providing step for providing a plate-shaped sub-frame; a battery cell block placement step of placing a battery cell block formed by bonding a plurality of battery cells to each other on a top surface of the subframe; a temporary assembly step of temporarily fixing a main frame having a cross-sectional shape with one side open and three surfaces closed to the sub-frame so that the battery cell blocks are accommodated therein; and a welding step in which the main frame and the sub-frame are welded to each other. The battery module according to the present invention comprises: a sub-frame having a plate shape; a battery cell block formed by coupling a plurality of battery cells to each other and disposed on a top surface of the subframe; and a main frame having a cross-sectional shape with one side open and three surfaces closed, coupled with the sub-frame such that the open side is closed by the sub-frame, and configured to accommodate the battery cell block therein, in which the main frame and the sub-frame are coupled and fixed to each other by welding.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2022-0067848, filed on Jun. 2, 2022, which is hereby incorporated by reference in its entirety. Technical Field

[0004] The present invention relates to a battery module in which a battery cell block stacked (combined) with a plurality of battery cells is installed in a space where a sub-frame and a main frame are combined with each other, and an assembling method of the battery module. More specifically, the present invention relates to a battery module that can improve cooling efficiency, make it easier to perform assembly and welding processes, and prevent spatter generated during welding from being introduced into the battery module, and an assembling method of the battery module. Background Art

[0005] A secondary battery having high energy density is mounted on an electric vehicle (EV) or a hybrid electric vehicle (HEV) and a portable device driven by an electric drive source.

[0006] Such secondary batteries not only have the major advantage of significantly reducing the use of fossil fuels, but also have the additional advantage of attracting attention as a new energy source with enhanced environmental friendliness and energy efficiency because no byproducts resulting from the use of energy are generated at all, and therefore, research on secondary batteries is being actively conducted.

[0007] Secondary batteries widely used in recent years include lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel metal hydride batteries, and nickel zinc batteries. In addition, the operating voltage of a unit battery cell, ie, a unit battery cell is about 2.5V to 4.2V.

[0008] Therefore, when a higher output voltage is required, a plurality of individual battery cells are connected to form a secondary battery module, and a plurality of battery modules are assembled to form a battery pack.

[0009] Here, the secondary battery module is configured by aggregating cylindrical secondary batteries or by aggregating pouch type secondary batteries.

[0010] Among them, in a battery module composed of soft-pack type secondary batteries, such as Figure 1 As shown, a longitudinal cross-section of a battery module according to the related art is shown, in which a plurality of battery cells of a soft-pack type secondary battery manufactured to be stacked in a predetermined number are installed in a frame 2 having a "U"-shaped cross-section, and the upper frame 2 has an open upper side and is arranged to face the bottom surface and two surfaces of the battery cell block 1.

[0011] In addition, a plate-like cover 3 is placed on the open upper side of the frame 2 to close the open upper side of the frame 2. The cover 3 is welded and joined in a state of being placed on the upper end portion of the frame 2 by brazing.

[0012] In addition, a cooling part 4 in which a refrigerant is calculated to cool the battery cell block 1 and the frame is coupled below the bottom surface of the frame 2 .

[0013] Since the battery module provided in the above configuration according to the related art must be managed in terms of flatness and size of a bending angle when the frame is bent in a “U” shape, there are problems of reduced productivity and quality.

[0014] In addition, when the battery cell block 1 is mounted, pressure is applied to the frame 2 to force the frame 2 (two wall surfaces) to expand, but in this process, the frame 2 may be deformed and / or cracked.

[0015] In addition, when the battery cells constituting the battery cell block 1 expand, cracks may occur at the brazing portion (welding portion) of the frame 2 and the cover 3. In addition, in order to improve the cooling performance of the cooling portion 4, the thickness of the frame 2 must be minimized at the portion provided between the battery cell block 1 and the cooling portion 4, but there is a problem of partial reduction in thickness due to processing characteristics of the frame 2 bent in a "U" shape.

[0016] In addition, when the upper end portion of the frame 2 is welded, spatter generated during welding is introduced into the frame 2 , and there is a risk of damaging the battery cell block 1 . Summary of the invention

[0017] Technical issues

[0018] Therefore, the main object of the present invention is to provide a battery module and an assembly method of the battery module, which can improve cooling efficiency and is easier and more reliably performed to improve production efficiency and reduce defect rate, so as to solve the problems of the battery module assembly method according to the related art (problems of frame deformation and / or cracks, problems of deterioration of cooling performance of the cooling part due to the thickness of the frame, and problems of spatters introduced into the interior due to the weight of the spatters themselves during welding).

[0019] Technical Solution

[0020] In order to achieve the above-mentioned purpose, the assembly method of the battery module according to the present invention includes: a sub-frame providing process, providing a sub-frame having a plate shape; a battery cell block placement process, placing a battery cell block in which a plurality of soft-pack type battery cells are stacked on each other on the top surface of the sub-frame; a temporary assembly process, temporarily fixing a main frame having a "U"-shaped cross-sectional shape with one side open and three surfaces closed to the sub-frame so that the battery cell block is accommodated inside; and a welding process, performing welding at a position where the main frame and the sub-frame contact each other.

[0021] An assembly hole may be punched in the main frame at a position facing each of the two ends of the sub-frame, and a protrusion that can be inserted into the assembly hole may be provided at each of the two ends of the sub-frame, and when the protrusion is inserted into the assembly hole, the main frame and the sub-frame are assembled to match each other to achieve temporary fixation.

[0022] A support portion protruding downward from each of both sides may be provided on the bottom surface of the sub-frame, and when the protrusion is inserted into the fitting hole, the main frame may abut against the support portion.

[0023] The support portion may have a height at which an end portion of the main frame can be spaced apart from the ground when the protrusion is fitted into the fitting hole.

[0024] The method may further include: a clamp pressing process, in which pressure is applied by a clamp so that the main frame and the sub-frame can be in close contact with each other, so that there is no gap at the position where the main frame and the sub-frame are assembled to each other, wherein the clamp pressing process can be performed before the welding process starts, and during the welding, the clamp can be configured to apply pressure to the part that temporarily fixes the main frame and the sub-frame to fix the main frame and the sub-frame.

[0025] The jig pressing process may include a correction process of adjusting a direction in which the pressure of the jig is applied to suppress generation of a height difference between the main frame and the sub-frame and distortion of the main frame and the sub-frame.

[0026] A through hole through which the welding laser can pass may be punched in the jig, and when the jig applies pressure to the main frame and the sub-frame, the welding laser may be irradiated through the through hole to weld the assembly parts.

[0027] The method may further include a cooling part coupling process of coupling, on a bottom surface of the sub-frame, a cooling part configured to cool the sub-frame by heat exchange with the sub-frame.

[0028] Furthermore, the present invention further provides a battery module manufactured by the battery module manufacturing method.

[0029] The battery module provided in the present invention includes: a subframe, which is in a plate shape; a battery cell block, which is assembled by combining a plurality of battery cells with each other, and the battery cell block is placed on the top surface of the subframe; and a main frame, which has a "U"-shaped cross-sectional shape with one side open and three surfaces closed, the main frame is combined with the subframe so that the open side is closed by the subframe, and the main frame is configured to accommodate the battery cell block therein, wherein the main frame and the subframe are combined and fixed to each other by welding.

[0030] An assembly hole may be punched at a portion of the main frame facing each of the two ends of the sub-frame, and a protrusion that can be inserted into the assembly hole may be provided on each of the two ends of the sub-frame, wherein the protrusion can be inserted into the assembly hole.

[0031] A support portion protruding downward from each of both sides may be provided on the bottom surface of the subframe, and the support portion may have a height at which an end of the main frame can be spaced apart from the ground when the protrusion is inserted into the assembly hole.

[0032] The protrusion may be inserted into the fitting hole so that welding is performed at a portion where the main frame abuts against the support portion.

[0033] The battery module may further include a cooling part coupled to a bottom surface of the sub-frame to cool the sub-frame.

[0034] Beneficial Effects

[0035] In the present invention having the above technical features, since the battery cell block is placed on the plate-shaped sub-frame, it is not necessary to apply excessive pressure to the two side wall surfaces of the main frame, thereby suppressing the generation of deformation and defects. Therefore, since the sizes of the sub-frame and the main frame remain constant, the generation efficiency can be better improved for optimization.

[0036] Since the assembly hole is defined in the main frame and the protrusion is provided on the sub-frame, the main frame and the sub-frame are welded in a state where the protrusion is temporarily fixed in the assembly hole, the welding quality can be improved and uniform welding can be achieved. When the main frame is combined, the assembly hole and the protrusion can be provided to provide a guiding function.

[0037] In addition, the support part can be provided on the sub-frame to increase the weldable area, and the main frame can be kept in close contact with the sub-frame. In addition, since the support part supports the load instead of the cooling part combined with the bottom surface of the sub-frame, the load can be prevented from being applied to the cooling part.

[0038] In addition, the cooling performance of the cooling part can be improved by reducing the thickness of the sub frame.

[0039] In addition, in the present invention, since laser welding is performed through the through hole defined in the jig, it is possible to prevent spatter generated during welding from being introduced into the inside. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a longitudinal sectional view showing a battery module according to the related art.

[0041] Figure 2 is an exploded perspective view showing a state in which a battery module according to the present invention is disassembled.

[0042] Figure 3 is a perspective view of a battery module according to the present invention.

[0043] Figure 4 It is along Figure 3 A cross-sectional view taken along line AA in FIG.

[0044] Figure 5 The figures sequentially show the assembly steps of the battery module assembly method according to the present invention.

[0045] Figure 6 yes Figure 5 Magnified view of the section where welding is performed. DETAILED DESCRIPTION

[0046] Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the technical concept of the present invention. However, the present invention can be implemented in different forms and should not be construed as being limited to the embodiments described herein.

[0047] In order to clearly describe the present invention, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification.

[0048] Furthermore, the terms or words used in the specification and claims should not be restrictively interpreted as ordinary meanings or dictionary-based meanings, but should be interpreted as meanings and concepts consistent with the scope of the present invention based on the principle that the inventor can appropriately define the concepts of the terms to best describe and interpret his or her invention.

[0049] The present invention relates to a battery cell block 10 and an assembly method of the battery cell block 10, in which a plurality of battery cells are mounted and combined (stacked) in a space where a sub-frame 20 and a main frame 30 are combined with each other. Hereinafter, embodiments provided in the present invention will be described in more detail with reference to the accompanying drawings.

[0050] First embodiment

[0051] The present invention provides a battery module according to a first embodiment.

[0052] Figure 2 is an exploded perspective view showing a state in which a battery module according to the present invention is disassembled, Figure 3 is a perspective view of a battery module according to the present invention, and Figure 4 It is along Figure 3 A cross-sectional view taken along line AA in FIG.

[0053] Referring to the drawings, a battery module provided in this embodiment includes a battery cell block 10 provided by stacking a plurality of battery cells, a sub-frame 20 having a plate shape, and a main frame 30 welded to be coupled with the sub-frame 20 .

[0054] Since the battery cell block 10 is provided by stacking battery cells each having a thin rectangular parallelepiped shape, the battery cell block 10 is in a rectangular parallelepiped shape of a predetermined thickness as a whole. In addition, the battery cell block 10 is placed on the top surface of the plate-shaped sub-frame 20. The sub-frame 20 is provided in a rectangular shape having an area slightly larger than that of the battery cell block 10.

[0055] The main frame 30 has a "U" shaped cross section with one side open and three surfaces closed, and is combined with the sub-frame 20 in a state where the open side is downward. That is, the main frame 30 is combined with the sub-frame 20 so that the open side is closed by the sub-frame 20. Therefore, the main frame 30 has a flat top surface 30b placed on the battery cell block 10 and a side wall surface 30a extending to each of both sides of the top surface 30b and bent downward, and the battery cell block 10 is accommodated in an internal space defined by the main frame 30 and the sub-frame 20.

[0056] In addition, the main frame 30 and the sub-frame 20 are welded to be combined at a portion where the main frame 30 and the sub-frame 20 contact each other.

[0057] In the present invention, the sub-frame 20 and the main frame 30 are configured to be assembled to match each other so that the sub-frame 20 and the main frame 30 are temporarily fixed before welding is performed.

[0058] That is, at the locations of the two ends of the main frame 30 respectively facing the sub-frame 20, a plurality of assembly holes 31 are punched in the lower ends of the two side wall surfaces 30a of the main frame 30 at certain intervals therebetween. The assembly holes 31 may have a circular shape or other shapes, but are arranged in a rectangular shape (such as Figure 2 As shown), the assembly hole 31 can be adjusted in the vertical direction, the horizontal direction and the front-rear direction when welding is performed.

[0059] In addition, a protrusion 21 that can be inserted into the assembly hole 31 at a location where the assembly hole 31 is provided when the main frame 30 enters is provided on each of the two end portions (both sides in the longitudinal direction) of the sub-frame 20. Therefore, the main frame 30 and the sub-frame 20 can be temporarily fixed by inserting the protrusion 21 into the assembly hole 31.

[0060] In addition, the support parts 22 protrude downward from both sides of the bottom surface of the sub-frame 20 with a gap therebetween. The height of the support parts 22 is such that when the protrusions 21 enter the assembly holes 31, the ends of the main frame 30 (more precisely, the ends of each of the side wall surfaces of the main frame) are spaced apart from the ground.

[0061] In addition, when the protrusion 21 is inserted into the fitting hole 31 , both side wall surfaces 30 a of the main frame 30 may be in contact with the support portion 22 , and welding may be performed at the contact location.

[0062] In addition, the cooling part 40 may be combined with the bottom surface of the sub-frame 20 to cool the sub-frame 20 and the battery cell block 10 by exchanging heat with the sub-frame 20 .

[0063] Second embodiment

[0064] The present invention provides a method for assembling a battery module according to a second embodiment.

[0065] Figure 5 are views sequentially showing the steps of assembling a battery module according to the assembling method of the present invention, and Figure 6 yes Figure 5 Magnified view of the section where welding is performed.

[0066] Reference Figure 5 and Figure 6 The battery module assembly method provided in this embodiment includes a subframe providing process, a battery cell block placement process, a temporary assembly process and a welding process.

[0067] That is to say, As shown, in the sub-frame providing process, the sub-frame 20 having a plate shape is provided, and in the battery cell block seating process, the battery cell block 10 is seated on the top surface of the sub-frame 20 .

[0068] Here, the battery cell block 10 is disposed at the center and does not deviate from the support portion 22 protruding from the bottom surface of the sub-frame 20 to each of both sides.

[0069] Then, as shown in the figure As shown, a temporary assembling process of temporarily fixing the main frame 30 to the sub-frame 20 is performed in a state where the battery cell block 10 is seated on the sub-frame 20 .

[0070] The main frame 30 is inserted slightly expanded in a state where the side wall surface 30a bent at each of both sides of the top surface 30b is elastically deformed, and when the force applied to the side wall surface 30a is released, as shown in FIG. <c>As shown, the side wall surface 30a is elastically restored, and the protrusion 21 of the sub-frame 20 is inserted into the fitting hole 31 defined by the main frame 30 and then temporarily fixed.

[0071] In a state where the sub-frame 20 and the main frame 30 are temporarily fixed, the contacting parts of the main frame 30 and the sub-frame 20 are welded. <d>As shown, to perform the welding process.

[0072] In addition, as described above, the two support portions 22 protrude downwardly spaced apart from each other on the bottom surface of the sub-frame 20 , and when the protrusion 21 is inserted into the fitting hole 31 , the side wall surface 30 a of the main frame 30 contacts the support portions 22 .

[0073] Here, if< / d> < / c> Figure 4 As shown, the support portion 22 has a height at which a lower end portion of the side wall surface 30 a of the main frame 30 can be spaced apart from the ground when the protrusion 21 is inserted into the fitting hole 31 .

[0074] Before (or while) performing the welding process, the jig pressing process in which the jig 50 applies pressure brings the main frame 30 and the sub-frame 20 into contact with each other so that there is no gap at a portion where the main frame 30 and the sub-frame 20 are assembled with each other.

[0075] The clamp pressing process is performed before or at the same time as the welding process starts, and the clamp 50 applies pressure to the temporarily fixed portion of the main frame 30 and the sub-frame 20 to prevent the main frame 30 and the sub-frame 20 from shaking. The clamp 50 continues to apply pressure while welding to fix the main frame 30 and the sub-frame 20.

[0076] The jig pressing process may include a correction process of adjusting the direction in which the pressure of the jig 50 is applied to suppress generation of a height difference between the main frame 30 and the sub-frame 20 and distortion of the main frame 30 and the sub-frame 20 .

[0077] That is to say, Figure 6 As shown, pressure may be applied so that welding is performed in a state where the protrusion 21 contacts the upper side of the fitting hole 31 ( state) or the protrusion 21 contacts the lower side of the fitting hole 31 (<II> state) according to the position of the main frame 30 .

[0078] However, in both cases (both ( state) and (<II> state)), preferably, pressure is applied in the lateral direction (left-right direction in the figure) so that the lowermost end of the side wall surface 30a is in close contact with the protrusion 21. Therefore, the clamp 50 can be divided into two parts 50a and 50b that can be moved independently, and a space can be defined between the two parts 50a and 50b so that the laser passes through between the two parts 50a and 50b (a through hole can be defined).

[0079] That is, a through hole 51 is punched in the jig 50 as a space through which the welding laser penetrates, so that welding is performed at a location where the side wall surface 30a of the main frame 30 and the support portion 22 of the sub-frame 20 abut against each other. When the jig 50 applies pressure to the main frame 30 and the sub-frame 20, the welding laser can be irradiated through the through hole 51 to perform welding at the assembly location.

[0080] In addition, a cooling part coupling process of coupling the cooling part 40 cooling the sub-frame 20 by heat exchange with the sub-frame 20 to the bottom surface of the sub-frame 20 may be performed. Here, the cooling part 40 may be installed to be disposed between the two support parts 22.

[0081] In the present invention having the above technical features, since the battery cell block 10 is placed on the sub-frame 20 having a plate shape, it is not necessary to apply excessive pressure to both side wall surfaces 30a of the main frame 30, thereby suppressing the generation of deformation and defects. Therefore, since the sizes of the sub-frame 20 and the main frame 30 can be kept constant, the production efficiency is improved.

[0082] Since the assembly hole 31 is defined in the main frame 30 and the protrusion 21 is provided on the sub-frame 20, welding is performed in a state where the protrusion 21 is temporarily fixed in the assembly hole 31, the welding quality can be improved and uniform welding can be achieved. When the main frame 30 is combined, the assembly hole 31 and the protrusion 21 can be provided to provide a guide function.

[0083] In addition, the support part 22 may be provided on the sub-frame 20 to increase the weldable area, and the main frame 30 may be kept in close contact with the sub-frame 20. In addition, since the support part 22 supports the load instead of the cooling part 40 coupled to the bottom surface of the sub-frame 20, the load may be prevented from being applied to the cooling part 40.

[0084] In addition, the cooling performance of the cooling portion 40 may be improved by reducing the thickness of the sub-frame 20 .

[0085] In addition, in the present invention, since laser welding is performed through the through hole 51 defined in the jig 50, it is possible to prevent spatter generated during welding from being introduced into the inside.

[0086] While embodiments of the present invention have been described with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.

[0087] [Explanation of Reference Numerals]

[0088] 10: Battery cell block

[0089] 20: Subframe

[0090] 21: Protrusion

[0091] 22: Supporting part

[0092] 30: Main frame

[0093] 31: Mounting hole

[0094] 40: Cooling unit

Claims

1. A method for assembling a battery module, the method comprising: A subframe providing step is to provide a subframe having a plate shape; a battery cell block placement process of placing a battery cell block in which a plurality of battery cells are combined with each other on a top surface of the sub-frame; a temporary assembly process of temporarily fixing a main frame having a cross-sectional shape with one side open and three surfaces closed to the sub-frame so that the battery cell block is accommodated inside; as well as The welding step is to perform welding at a location where the main frame and the sub-frame contact each other.

2. The assembly method according to claim 1, wherein: A mounting hole is punched in a portion of the main frame facing each of the two end portions of the sub-frame, and a protrusion that can be inserted into the mounting hole is provided at each of the two end portions of the sub-frame, and When the protrusion is inserted into the assembly hole, the main frame and the sub-frame are assembled to match each other to achieve temporary fixation.

3. The assembly method according to claim 2, wherein: A support portion protruding downward from each of both sides is provided on a bottom surface of the sub-frame, and when the protrusion is inserted into the fitting hole, the main frame abuts against the support portion.

4. The assembly method according to claim 3, wherein: The support portion has a height at which the end of the main frame can be spaced apart from the ground when the protrusion is fitted into the fitting hole.

5. The assembly method according to claim 1, further comprising: A clamp pressing process, in which pressure is applied by a clamp so that the main frame and the sub-frame can be in close contact with each other, so that there is no gap at the position where the main frame and the sub-frame are assembled with each other. The jig pressing process is performed before the welding process starts, and the jig is configured to apply pressure to a portion temporarily fixing the main frame and the sub-frame to fix the main frame and the sub-frame during the welding process.

6. The assembly method according to claim 5, wherein: The jig pressing process includes a correction process of adjusting a direction in which a pressure of the jig is applied to suppress generation of a height difference between the main frame and the sub-frame and distortion of the main frame and the sub-frame.

7. The assembly method according to claim 5, wherein: A through hole through which a welding laser can pass is punched in the jig, and when the jig applies pressure to the main frame and the sub-frame, the welding laser is irradiated through the through hole to weld the assembly parts. 8 . The assembling method according to claim 1 , further comprising a cooling portion bonding process of bonding, on a bottom surface of the sub-frame, a cooling portion configured to cool the sub-frame by exchanging heat with the sub-frame.

9. A battery module, comprising: A subframe, wherein the subframe is in a plate shape; a battery cell block assembled by combining a plurality of battery cells with each other and seated on a top surface of the sub-frame; as well as A main frame having a cross-sectional shape with one side open and three surfaces closed, the main frame being combined with the sub-frame so that the open side is closed by the sub-frame, and the main frame being configured to accommodate the battery cell block in, Wherein, the main frame and the sub-frame are combined and fixed to each other by welding.

10. The battery module according to claim 9, wherein: An assembly hole is punched in a portion of the main frame facing each of the two ends of the sub-frame, and a protrusion that can be inserted into the assembly hole is provided at each of the two ends of the sub-frame, wherein the protrusion is inserted into the assembly hole.

11. The battery module according to claim 10, wherein: A support portion protruding downward from each of both sides is provided on a bottom surface of the sub-frame and has a height at which an end of the main frame can be spaced apart from the ground when the protrusion is inserted into the fitting hole.

12. The battery module according to claim 11, wherein: The protrusion is inserted into the fitting hole so that welding is performed at a portion where the main frame abuts against the support portion. 13 . The battery module according to claim 9 , further comprising a cooling part coupled to a bottom surface of the sub-frame to cool the sub-frame.

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