Battery module and method for assembling same

Abstract

A method for assembling a battery module according to the present invention includes a subframe providing step of providing a subframe having a plate shape; a cell block mounting step of mounting a cell block, having a plurality of battery cells coupled thereto, on an upper surface of the subframe; a pre-assembly step of pre-fixing a main frame having a cross-sectional shape with one side open and three sides closed to the subframe so that the cell block can be accommodated therein; and a welding step of welding a contact point between the main frame and the subframe; The battery module according to the present invention includes a subframe having a plate shape; a cell block, having a cross-sectional shape with one side open and three sides closed, configured to couple a plurality of battery cells together and mounted on an upper surface of the subframe; and a main frame, having a cross-sectional shape with one side open and three sides closed, coupled to the subframe so that the open side is closed by the subframe and housing the cell block therein; and the main frame and the subframe are joined and fixed by welding.

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0067848 filed on June 2, 2022, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a battery module in which a cell block in which a plurality of battery cells are stacked (combined) is mounted inside a space formed by combining a subframe and a mainframe, and an assembling method thereof, and more particularly, to a battery module and an assembling method thereof that can increase cooling efficiency, facilitate assembly and welding processes, and prevent spatter generated during welding from entering the interior. [Background technology]

[0003] 2. Description of the Related Art Secondary batteries having high energy density are mounted not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs) that are driven by an electric drive source.

[0004] Such secondary batteries have attracted attention as a new energy source for improving the environment and energy efficiency, not only because of the primary advantage of dramatically reducing the use of fossil fuels, but also because they do not produce any by-products due to the use of energy, and active research and development is being conducted on them.

[0005] Currently widely used types of secondary batteries include lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel metal hydride batteries, nickel zinc batteries, etc. The operating voltage of such unit battery cells is about 2.5V to 4.2V.

[0006] Therefore, when a higher output voltage is required, a secondary battery module is formed by connecting a plurality of individual battery cells, and a battery pack is formed by assembling a plurality of battery modules.

[0007] In this case, the battery module is formed by assembling cylindrical secondary batteries or pouch-type secondary batteries.

[0008] Of these, a battery module made of pouch-type secondary batteries has a cell block 1, which is made by stacking a predetermined number of battery cells manufactured using pouch-type secondary batteries, mounted in a frame 2 having a U-shaped cross section, as shown in FIG. 1, which shows a cross section of a conventional battery module. The frame 2 is open at the top and is provided to face the bottom and both side surfaces of the cell block 1.

[0009] A plate-shaped cover 3 was mounted on the open upper side of the frame 2 to close the open upper side of the frame 2. The cover 3 was attached to the upper end of the frame 2 by welding using a brazing method.

[0010] At the same time, a cooling section 4 was attached to the lower bottom surface of the frame 2, through which a coolant circulates to cool the cell block 1 and the frame 2.

[0011] Meanwhile, the conventional battery module provided with the above configuration has a problem in that the dimensions of flatness and bending angle must be controlled when bending the frame into a "U" shape, resulting in a decrease in productivity and quality.

[0012] In addition, when the cell block 1 is installed, pressure is applied to the frame 2 to force it open (both side walls), which may cause deformation and / or cracks in the frame 2 during the process.

[0013] Furthermore, when swelling occurs in the battery cells that make up the cell block 1, cracks can occur at the brazing (welding) portion of the frame 2 and the cover 3. Furthermore, in order to improve the cooling performance of the cooling unit 4, the thickness of the frame 2 must be minimized in the portion located between the cell block 1 and the cooling unit 4, but due to the processing characteristics of the frame 2, which is bent into a "U" shape, there was a problem in that it was not possible to reduce the thickness partially.

[0014] At the same time, since welding is performed on the upper end of the frame 2, there is a risk that spatters generated during welding may flow into the inside of the frame 2 and damage the cell block 1. Summary of the Invention [Problem to be solved by the invention]

[0015] Therefore, the present invention has as its main objective the provision of a battery module and an assembly method thereof, which can increase cooling efficiency to eliminate problems associated with conventional battery modules (such as problems of frame deformation and / or cracks, problems of reduced cooling performance of the cooling part due to the thickness of the frame, and problems of spatter flowing into the interior due to its own weight during welding) and can increase production efficiency and reduce defect rates by making the assembly and welding processes easier and more reliable. [Means for solving the problem]

[0016] In order to achieve the above-mentioned object, a method for assembling a battery module according to the present invention includes a subframe providing step of providing a plate-shaped subframe; a cell block mounting step of mounting a cell block (composed of a plurality of stacked pouch-type battery cells) on an upper surface of the subframe; a pre-assembly step of pre-fixing a main frame having a U-shaped cross-section with one side open and three sides closed to the subframe so that the cell block can be accommodated therein; and a welding step of welding a point where the main frame and the subframe contact each other.

[0017] The main frame has fitting holes drilled at points facing both ends of the subframe, and both ends of the subframe have protrusions formed thereon that can enter the fitting holes. The main frame and the subframe are temporarily fixed by fitting them together as the protrusions enter the fitting holes.

[0018] The sub-frame has a lower surface on both sides thereof having pedestals protruding downward, and when the protrusions enter the insertion holes, the main frame abuts against the pedestals.

[0019] When the projection is fitted into the fitting hole, the base has a height sufficient to space the end of the main frame from the ground.

[0020] The method further includes a jig pressing step of applying pressure through a jig to seal the main frame and the sub frame so that there is no gap at the point where they are fitted together, and the jig pressing step is performed before the welding step starts (or at the same time as the welding step starts), and while the welding is proceeding, the jig applies pressure to the portion where the main frame and the sub frame are temporarily fixed to fix them in place.

[0021] The jig pressing step may include a correction step of adjusting a direction in which the jig pressure is applied so as to prevent occurrence of a step and twist between the main frame and the sub frame.

[0022] The jig has a through hole through which a welding laser can pass, and while the jig applies pressure to the main frame and the sub-frame, the welding laser is irradiated through the through hole to weld the fitted points.

[0023] The method further includes the step of: bonding a cooling part to a lower surface of the subframe, the cooling part exchanging heat with the subframe to cool the lower surface of the subframe.

[0024] At the same time, the present invention further provides a battery module that can be manufactured by the above-mentioned battery module manufacturing method.

[0025] The battery module provided in the present invention includes a plate-shaped subframe; a cell block formed by combining a plurality of battery cells and mounted on an upper surface of the subframe; and a main frame having a U-shaped cross-section with one side open and three sides closed, the cell block being housed inside the main frame and combined with the subframe so that the open side is closed by the subframe; and the main frame and the subframe are fixedly joined by welding.

[0026] The main frame has fitting holes drilled at points facing both ends of the subframe, and both ends of the subframe have protrusions formed thereon that can enter the fitting holes, and the protrusions are inserted into the fitting holes.

[0027] A pedestal portion protrudes downward from both sides of the lower surface of the subframe, and the pedestal portion is formed to have a height sufficient to separate the end of the main frame from the ground when the protrusions enter the fitting holes.

[0028] The projections are inserted into the fitting holes and welding is performed at the points where the main frame abuts the base.

[0029] The cooling unit may further include a cooling unit coupled to a lower surface of the sub-frame for cooling the sub-frame. Effect of the Invention

[0030] The present invention having the above-mentioned technical features has a structure in which the cell block is mounted on a plate-shaped subframe, and there is no need to apply excessive pressure to both side walls of the mainframe, which can suppress the occurrence of deformation and defects. This allows the dimensions of the subframe and the mainframe to be stabilized, thereby further increasing and optimizing production efficiency.

[0031] The main frame has a fitting hole and the sub frame has a protrusion, and welding is performed with the protrusion temporarily fixed in the fitting hole, so that the welding quality can be improved and the welding can be performed uniformly. The fitting hole and the protrusion can provide a guide function when the main frame is assembled.

[0032] In addition, since the subframe is formed with a pedestal, an area that can be welded can be increased, and the mainframe can be kept in close contact with the subframe. Also, since the pedestal can support a load instead of the cooling unit coupled to the bottom surface of the subframe, it is possible to prevent the load from being applied to the cooling unit.

[0033] At the same time, by reducing the thickness of the subframe, the cooling performance of the cooling section can be further improved.

[0034] In addition, in the present invention, since laser welding is performed through the through holes formed in the jig, it is possible to eliminate the problem of spatters generated during welding flowing into the interior. [Brief description of the drawings]

[0035] [Figure 1] 1 is a view showing a vertical cross section of a conventional battery module. [Diagram 2]FIG. 2 is an exploded perspective view showing a battery module according to the present invention in an exploded state; [Diagram 3] 1 is a perspective view of a battery module according to the present invention; [Figure 4] 4 is a diagram showing a cross-sectional shape of a portion AA in FIG. 3. [Diagram 5] 2 is a diagram showing sequentially how an assembly is performed according to a battery module assembly method provided by the present invention; [Figure 6] 6 is an enlarged view of the portion in FIG. 5 where welding is performed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, in order to enable those skilled in the art to easily carry out their practice of the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments set forth herein.

[0037] In order to clearly describe the present invention, parts that are not relevant to the description will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0038] Furthermore, the terms and words used in this specification and the claims should not be interpreted in a limited manner to their ordinary and dictionary meanings, but should be interpreted in a manner that is consistent with the technical ideas of the present invention, based on the principle that the inventor himself / herself may appropriately define the concepts of terms in order to explain the invention in the best possible manner.

[0039] The present invention relates to a battery module in which a cell block 10 is mounted with a plurality of battery cells combined (stacked) inside a space formed by combining a subframe 20 and a main frame 30, and an assembly method thereof. Hereinafter, an embodiment of the present invention will be described in more detail with reference to the accompanying drawings.

[0040] First Example The present invention provides a battery module as a first embodiment.

[0041] FIG. 2 is an exploded perspective view showing a disassembled state of a battery module according to the present invention, FIG. 3 is a perspective view of a battery module according to the present invention, and FIG. 4 is a view showing a cross-sectional shape of portion AA in FIG. 3.

[0042] Referring to the figure, the battery module provided in this embodiment includes a cell block 10 in which a plurality of battery cells are stacked, a plate-shaped subframe 20, and a main frame 30 which is joined to the subframe 20 by welding.

[0043] The cell block 10 has a rectangular parallelepiped shape with a predetermined thickness as a result of thin rectangular parallelepiped battery cells being stacked. The cell block 10 is mounted on an upper surface of a plate-shaped subframe 20. The subframe 20 is formed in a rectangular shape with an area slightly larger than that of the cell block 10.

[0044] The main frame 30 has a U-shaped cross section with one side open and three sides closed, and is coupled to the sub-frame 20 with the open side facing downward. That is, the main frame 30 is coupled to the sub-frame 20 such that the open side is closed by the sub-frame 20. As a result, the main frame 30 has a flat top surface 30b placed on the cell block 10 and side wall surfaces 30a extending on both sides of the top surface 30b and bent downward, and the cell block 10 is accommodated in an internal space formed by the main frame 30 and the sub-frame 20.

[0045] The main frame 30 and the sub-frame 20 are joined by welding at the points where they come into contact with each other.

[0046] On the other hand, in the present invention, the subframe 20 and the main frame 30 are configured to be fitted together so that they are temporarily fixed to each other before welding is performed.

[0047] That is, a plurality of fitting holes 31 are drilled at intervals on the lower ends of both side walls 30a of the main frame 30 at points facing both ends of the sub-frame 20. The fitting holes 31 may have a circular or other shape, and are provided in a rectangular shape (as shown in FIG. 2) so that they can be uniformly adjusted in the up-down, left-right, and front-back directions when welding is performed.

[0048] In addition, protrusions 21 that can enter the fitting holes 31 are formed on both ends of the subframe 20 (on both sides along the longitudinal direction) at points where the fitting holes 31 will be located when the mainframe 30 enters. As a result, the mainframe 30 and the subframe 20 can be temporarily fixed together by inserting the protrusions 21 into the fitting holes 31.

[0049] At the same time, pedestals 22 protrude downward from both sides of the lower surface of the sub-frame 20 at a distance from each other. The pedestals 22 are formed to have a height sufficient to separate the end of the main frame 30 (more precisely, the end of the side wall of the main frame) from the ground when the protrusions 21 enter the fitting holes 31.

[0050] When the protrusion 21 is inserted into the insertion hole 31, both side walls 30a of the main frame 30 may abut against the base 22, and welding may be performed at the abutting points.

[0051] At the same time, a cooling unit 40 may be coupled to a lower surface of the subframe 20 to exchange heat with the subframe 20 and cool the subframe 20 and the cell block 10 .

[0052] Second Example The present invention provides a method for assembling a battery module as a second embodiment.

[0053] FIG. 5 is a diagram sequentially showing how an assembly is performed according to a battery module assembly method provided by the present invention, and FIG. 6 is an enlarged view of a portion where welding is performed in FIG. 5.

[0054] 5 and 6, the method of assembling the battery module provided in this embodiment includes a subframe providing step, a cell block mounting step, a pre-assembly step, and a welding step.

[0055] That is, in Fig. 5 1, in the sub-frame providing step, a plate-shaped sub-frame 20 is provided, and in the cell block mounting step, the cell block 10 is mounted on an upper surface of the sub-frame 20.

[0056] At this time, the cell block 10 is positioned at the center so as not to come off the pedestals 22 protruding from the bottom surface of the sub-frame 20 on both sides.

[0057] And in Figure 5 2, with the cell block 10 seated on the sub-frame 20, a pre-assembly step is performed in which the main frame 30 is pre-fixed to the sub-frame 20.

[0058] The main frame 30 is inserted with the side walls 30a, which are bent on both sides of the upper surface 30b, slightly open in a state where they are elastically deformed. When the force applied to the side walls 30a is released, the main frame 30 is inserted as shown in FIG. <c>2, the side wall surface 30a is elastically restored, and the protrusion 21 of the sub-frame 20 is fitted into the fitting hole 31 formed in the main frame 30, thereby performing temporary fixing.

[0059] In a state where the subframe 20 and the main frame 30 are temporarily fixed to each other, the points where the main frame 30 and the subframe 20 come into contact with each other are shown in FIG. <d>The welding step is performed by welding as shown in FIG.

[0060] As described above, two pedestals 22 protrude downward from the lower surface of the sub-frame 20 at a distance from each other, and when the protrusions 21 enter the insertion hole 31, the side wall surface 30a of the main frame 30 abuts against the pedestals 22.

[0061] At this time, when the protrusion 21 is fitted into the fitting hole 31, as shown in FIG. 4, the base 22 has a height sufficient to space the lower end of the side wall surface 30a of the main frame 30 from the ground.

[0062] Meanwhile, before the welding step is performed (or at the same time as the welding step is performed), a jig pressurizing step is performed in which pressure is applied through a jig 50 to seal the main frame 30 and the sub-frame 20 together so that there is no gap at the points where the main frame 30 and the sub-frame 20 are fitted together.

[0063] The jig pressurizing step is performed before or simultaneously with the start of the welding step, and the jig 50 applies pressure to the portion where the main frame 30 and the sub-frame 20 are temporarily fixed to prevent shaking. The jig 50 continues to apply pressure to fix the portions while the welding is in progress.

[0064] The jig pressing step may include a correction step of adjusting the direction in which the pressure of the jig 50 is applied so as to prevent the occurrence of a step and twist between the main frame 30 and the sub-frame 20.

[0065] That is, as shown in FIG. 6, depending on the position of the main frame 30, the welding is performed in a state where the protrusion 21 abuts on the upper side of the fitting hole 31 ( state), and welding proceeds with the protrusion 21 abutting the lower part of the fitting hole 31 ( <ii>Pressure may be applied so that the

[0066] However, there are two cases ( Status and <ii>It is preferable that pressure is applied in a lateral direction (left and right direction in the drawing) so that the bottom end of the side wall surface 30a is in close contact with the protrusion 21. Therefore, the jig 50 is divided into two parts 50a and 50b that can be moved independently, and a space can be formed between them (a through hole can be formed) so that the laser can pass through.

[0067] That is, in order to perform welding at the points where the side wall surface 30a of the main frame 30 and the base portion 22 of the subframe 20 abut, the jig 50 is drilled with a through hole 51 as a space through which a welding laser can pass, and while the jig 50 applies pressure to the main frame 30 and the subframe 20, a welding laser can be irradiated through the through hole 51 to perform welding at the fitted points.

[0068] A cooling unit joining step may be performed in which a cooling unit 40 for exchanging heat with the sub-frame 20 and cooling the lower surface of the sub-frame 20 is joined to the lower surface of the sub-frame 20. In this case, the cooling unit 40 may be attached to be located between the two pedestals 22.

[0069] The present invention having the technical features as described above has a structure in which the cell block 10 is seated on the plate-shaped subframe 20, and there is no need to apply excessive pressure to the side walls (30a) of the mainframe 30, thereby preventing deformation and defects. This allows the dimensions of the subframe 20 and the mainframe 30 to be stabilized, thereby increasing production efficiency.

[0070] The main frame 30 has an insertion hole 31, and the sub-frame 20 has a protrusion 21, and welding is performed with the protrusion 21 temporarily fixed in the insertion hole 31, improving welding quality and allowing for uniform welding. The insertion hole 31 and the protrusion 21 provide a guide function when the main frame 30 is assembled.

[0071] In addition, the subframe 20 is formed with a base 22, which increases the area that can be welded and allows the mainframe 30 to maintain a state of being in close contact with the subframe 20. In addition, the base 22 can support a load instead of the cooling unit 40 coupled to the bottom surface of the subframe 20, so that the load can be prevented from being applied to the cooling unit 40.

[0072] At the same time, by reducing the thickness of the subframe 20, the cooling performance of the cooling section 40 can be further improved.

[0073] In addition, in the present invention, since laser welding is performed through the through-hole 51 formed in the jig 50, the problem of spatters generated during welding flowing into the internal space can be eliminated.

[0074] The present invention has been described above using limited examples and drawings, but the present invention is not limited thereto, and various implementations are possible within the technical spirit of the present invention and the equivalent scope of the claims described below by a person having ordinary knowledge in the technical field to which the present invention belongs. [Explanation of symbols]

[0075] 10 Cell Block 20 Subframe 21 Protrusion 22 Base 30 Mainframe 31 Inset Hole 40 Cooling section< / ii> < / ii> < / d> < / c>

Claims

1. A method for assembling a battery module, comprising the steps of: providing a subframe having a plate shape; a cell block mounting step of mounting a cell block, to which a plurality of battery cells are combined, on an upper surface of the subframe; a pre-assembly step of pre-fixing a main frame having a cross-sectional shape with one side open and three sides closed to a sub frame so that the cell block can be accommodated therein; and welding the main frame and the sub-frame at a contact point.

2. The main frame has fitting holes at points facing both ends of the subframe, and protrusions are formed at both ends of the subframe to be able to enter the fitting holes; The method for assembling a battery module according to claim 1 , wherein the main frame and the sub frame are temporarily fixed to each other by fitting the main frame and the sub frame together with the protrusions inserted into the fitting holes.

3. 3. The method of claim 2, wherein a base portion protrudes downward from both sides of a lower surface of the subframe, and the mainframe abuts against the base portion when the protrusions enter the insertion holes.

4. The method of assembling a battery module according to claim 3 , wherein the base has a height sufficient to space an end of the main frame from the ground when the protrusion is fitted into the fitting hole.

5. The method further includes a jig pressing step of applying pressure to the main frame and the sub frame through a jig so that there is no gap at a position where the main frame and the sub frame are fitted together, 2. The method of assembling a battery module according to claim 1, wherein the jig pressurizing step is performed before a welding step is started, and while the welding is proceeding, the jig applies pressure to a portion where the main frame and the sub frame are temporarily fixed to fix them.

6. 6. The method of claim 5, wherein the jig pressing step includes a correction step of adjusting a direction in which the jig pressure is applied to prevent occurrence of a step and twist between the main frame and the sub frame.

7. 6. The method of assembling a battery module according to claim 5, wherein the jig has a through-hole through which a welding laser can pass, and while the jig applies pressure to the main frame and the sub-frame, a welding laser is irradiated through the through-hole to weld the fitted points.

8. 2. The method of assembling a battery module according to claim 1, further comprising: joining a cooling part to a lower surface of the subframe, the cooling part exchanging heat with the subframe to cool the lower surface of the subframe.

9. A battery module, A subframe having a plate shape; a cell block including a plurality of battery cells coupled together and mounted on an upper surface of the subframe; a main frame having a cross-sectional shape with one side open and three sides closed, the main frame being coupled to the sub frame so that the open side is closed by the sub frame, and accommodating the cell block therein; The main frame and the sub frame are joined and fixed to each other by welding.

10. 10. The battery module of claim 9, wherein fitting holes are drilled in the main frame at points facing both ends of the sub frame, and protrusions are formed at both ends of the sub frame to be able to enter the fitting holes, and the protrusions are inserted into the fitting holes.

11. 11. The battery module of claim 10, wherein a pedestal protrudes downward from both sides of a lower surface of the subframe, the pedestal having a height sufficient to separate an end of the mainframe from the ground when the protrusions are inserted into the fitting holes.

12. The battery module according to claim 11 , wherein a protrusion is inserted into the fitting hole, and welding is performed at a point where the main frame abuts against the base.

13. The battery module of claim 9 , further comprising a cooling part coupled to a lower surface of the subframe and configured to cool the subframe.

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