Battery module and method for manufacturing the battery module

Abstract

The present invention relates to a battery module and a manufacturing method thereof, which can prevent breakage of welded parts such as a cooling plate during insertion and assembly of a cell block assembly, and can prevent defects in the battery module by preventing breakage of welded parts such as a cooling plate even when swelling of the battery module occurs as the battery module is used for an extended period of time, thereby realizing a product with a significantly excellent concept. The battery module according to the present invention includes a cell block assembly which is an assembly of a plurality of cells, a bottom plate disposed on one side of the cell block assembly, a frame which encloses the other side and side of the cell block assembly, and end plates disposed on the front and rear of the cell block assembly.

Description

[Technical field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0064917 filed on May 26, 2022 and Korean Patent Application No. 10-2023-0044614 filed on April 5, 2023, and all contents disclosed in the documents of said Korean patent applications are incorporated by reference into this specification.

[0002] The present invention relates to a battery module and a manufacturing method thereof, which can prevent breakage of welded parts of parts such as a cooling plate during insertion and assembly of a cell block assembly, and can also prevent breakage of welded parts of parts such as a cooling plate even when swelling of the battery module occurs as the battery module is used for an extended period of time, thereby preventing defects in the battery module, thereby realizing a product with an extremely excellent concept. [Background technology]

[0003] In recent years, as the price of energy sources has risen sharply due to the depletion of fossil fuels and concerns about environmental pollution have grown, the need for environmentally friendly alternative energy sources has become an essential element for future life. As a result, research into various electricity production technologies, such as solar, wind, and tidal power, has been ongoing, and there has also been great interest in power storage devices such as batteries to more efficiently use the electrical energy produced in this way.

[0004] Furthermore, with the increasing development and demand for battery-based electronic mobile devices and electric vehicles, the demand for batteries as an energy source is increasing rapidly, and as a result, various research projects are being conducted on batteries that can meet various needs.

[0005] In particular, in terms of materials, there is a high demand for lithium secondary batteries, such as lithium ion batteries and lithium ion polymer batteries, which have advantages such as high energy density, discharge voltage, and output stability.

[0006] Depending on the shape of the battery case, secondary batteries can be divided into cylindrical batteries and prismatic batteries in which the electrode assembly is assembled in a cylindrical or prismatic metal case, and pouch batteries in which the electrode assembly is assembled in a pouch case made of an aluminum laminate sheet. However, the operating voltage of such a unit cell, i.e., a unit battery cell, is about 2.5V to 4.2V.

[0007] 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.

[0008] Fig. 1 is a cross-sectional view of a frame portion of a conventional battery module, and Fig. 2 is a cross-sectional view illustrating a state in which a cell block assembly is inserted into the frame of Fig. 1.

[0009] 1 and 2, a battery module formed of a pouch-type secondary battery has a cell block assembly 10 formed by stacking a predetermined number of battery cells manufactured as pouch-type secondary batteries, and the cell block assembly 10 is mounted in a frame 20 having a U-shaped cross section, and the frame 20 is open at the top and is provided to face the bottom and both side surfaces of the cell block assembly 10.

[0010] Although not shown in the drawings, a top plate can be attached to the open upper side of the frame by brazing, and end plates can be attached to the front and rear of the frame to form a battery module having a generally rectangular parallelepiped shape. Also, a cooling plate 30, through which a refrigerant circulates to cool the cell block assembly 10 and the frame 20, can be attached to the lower surface of the frame by brazing.

[0011] Referring to FIG. 2 showing the insertion of a cell block assembly into the frame of FIG. 1, in the past, in order to insert the cell block assembly into the frame, the side walls of the frame were opened on both sides B and B', and the cell block assembly was inserted while moving downward D. During this process, the shape of the bottom of the frame could bend upward into a convex shape. In addition, during this process, there was a problem that the brazing weld W of the cooling plate attached under the bottom of the frame could break (or be damaged). In addition, when swelling of the battery module occurs as the usage time of the battery module increases, the welds of parts such as the cooling plate could break, which was a problem. This was a problem because it could cause the battery module to fail, making it impossible to realize a product with an excellent concept. Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention has been made to solve the above problems, and an object of the present invention is to provide a battery module and a manufacturing method for a battery module, which can prevent breakage of welded parts of parts such as a cooling plate during insertion and assembly of a cell block assembly, and can also prevent breakage of welded parts of parts such as a cooling plate even when swelling of the battery module occurs as the battery module is used for an extended period of time, thereby preventing defects in the battery module and thereby realizing a product with an extremely excellent concept. [Means for solving the problem]

[0013] The battery module according to the present invention includes a cell block assembly which is an assembly of a plurality of cells, a bottom plate disposed on one side of the cell block assembly, a frame which encloses the other side and side of the cell block assembly, and end plates disposed on the front and rear of the cell block assembly.

[0014] The bottom plate may further include a cooling plate coupled to one surface of the bottom plate on one side thereof.

[0015] The cooling plate may be joined to one side of the bottom plate by braze welding.

[0016] The frame can include a ceiling portion that encases the other surface of the cell block assembly, and a sidewall portion that encases the side surface of the cell block assembly.

[0017] The ceiling and sidewalls may be integrally formed.

[0018] One side end of the side wall portion and both side ends of the bottom plate can be joined by welding.

[0019] The sidewall portion may include a first sidewall portion facing the cell block assembly, and a second sidewall portion connected to the first sidewall portion in a stepped form on one side of the first sidewall portion and extending in a direction toward one side of the first sidewall portion.

[0020] The bottom plate may include a first plate portion extending in a direction parallel to one surface of the cell block assembly while facing the cell block assembly, and a second plate portion extending from both side ends of the first plate portion in a direction away from the cell block assembly.

[0021] The end of the second side wall portion and the end of the second plate portion may be joined to each other by a weld W.

[0022] The cell block assembly may further include an insulating film disposed between the frame and the cell block assembly.

[0023] The insulating film includes a horizontal portion disposed between the ceiling portion and the cell block assembly and a vertical portion disposed between the sidewall portion and the cell block assembly, and the horizontal portion and the vertical portion may be formed integrally.

[0024] The cell block assembly may further include a thermal resin disposed between the other surface of the bottom plate and the one surface of the cell block assembly.

[0025] A method for manufacturing a battery module according to the present invention includes the steps of preparing a bottom plate having a cooling plate attached to one side thereof, placing a cell block assembly, which is an assembly of a plurality of cells, on the other side of the bottom plate, attaching a frame to the bottom plate so as to enclose the other side and side of the cell block assembly, and attaching end plates to the front and rear of the cell block assembly.

[0026] The step of bonding the frame to the bottom plate may include bonding a frame having an insulating sheet bonded to an inner surface thereof to the bottom plate.

[0027] The step of placing the cell block assembly may include placing the cell block assembly on the other surface of the bottom plate with a thermal resin disposed between the cell block assembly and the bottom plate.

[0028] The step (S03) of bonding the frame to the bottom plate may include bonding a frame having an insulating sheet bonded to an inner surface thereof to the bottom plate. Effect of the Invention

[0029] The battery module and the manufacturing method of the battery module according to the present invention can prevent breakage of welded parts such as a cooling plate during the insertion and assembly of the cell block assembly. Even when swelling of the battery module occurs as the usage time of the battery module increases, breakage of welded parts such as a cooling plate can be prevented, thereby preventing defects in the battery module and thereby realizing a product with a significantly excellent concept. [Brief description of the drawings]

[0030] [Figure 1] FIG. 11 is a cross-sectional view of a frame portion in a conventional battery module. [Diagram 2] 2 is a cross-sectional view illustrating the insertion of a cell block assembly into the frame of FIG. 1. [Diagram 3] FIG. 1 is an exploded perspective view of a battery module according to a first embodiment of the present invention. [Figure 4] 1 is a cross-sectional view illustrating a method for assembling a battery module according to embodiment 1 of the present invention. [Diagram 5] 1 is a cross-sectional view showing an assembled state of a battery module according to a first embodiment of the present invention. [Figure 6] 4 is a diagram illustrating a method for manufacturing a battery module according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following, 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 carry out the present invention. However, the present invention may be embodied in various different forms and is not limited to the following embodiments.

[0032] In order to clearly explain the present invention, detailed descriptions of parts that are not relevant to the description or related known technologies that may obscure the gist of the present invention have been omitted, and when referring to components in each drawing in this specification, the same or similar reference symbols will be used for the same or similar components throughout the specification.

[0033] Furthermore, the terms and words used in this specification and the claims should not be interpreted in a limited manner to their ordinary or dictionary meanings, but should be interpreted in a manner that is consistent with the technical idea of ​​the present invention, based on the principle that the inventors can appropriately define the concepts of terms in order to best describe their invention.

[0034] EMBODIMENT 1 Fig. 3 is an exploded perspective view of the battery module according to the first embodiment of the present invention. Fig. 4 is a cross-sectional view illustrating a method of assembling the battery module according to the first embodiment of the present invention. Fig. 5 is a cross-sectional view illustrating the assembled state of the battery module according to the first embodiment of the present invention.

[0035] 3 and 5, the battery module according to the first embodiment of the present invention may include a cell block assembly 110, a bottom plate 140, a frame 120, and an end plate 150. In addition, the battery module may further include a cooling plate 130.

[0036] The cell block assembly 110 may be an assembly of a plurality of battery cells, specifically, a cell assembly formed by stacking a predetermined number of battery cells manufactured as pouch-type secondary batteries.

[0037] The bottom plate 140 may be configured to be disposed on one surface of the cell block assembly 110. Here, the one surface may be, for example, a lower surface of the cell block assembly. The bottom plate 140 may have a simple flat plate shape, or may have a flat plate shape with a part deformed. For example, in the first embodiment of the present invention, the bottom plate 140 may include a first plate portion 141 and a second plate portion 142. The first plate portion 141 may be a portion that faces the cell block assembly 110 and extends in a direction parallel to one surface of the cell block assembly 110. With reference to FIG. 5, the direction parallel to one surface of the cell block assembly 110 may mean a horizontal direction. That is, the first plate portion 141 may be a portion of the bottom plate 140 that extends in a horizontal direction parallel to one surface of the cell block assembly 110. The second plate portion 142 may be a portion that extends in a direction away from the cell block assembly 110 at both ends of the first plate portion 141. 5, the direction away from the cell block assembly 110 may be a vertically downward direction. That is, the portions vertically connected to both ends of the horizontally extending first plate portion 141 and extending downward may be the second plate portion 142. This configuration may have the advantage of increasing the cooling area.

[0038] The frame 120 may be a structure that encases the other surface and side of the cell block assembly 110. Here, as an example, the other surface may refer to the top surface of the cell block assembly 110. That is, the frame 120 may be a structure that encases the top surface and side of the cell block assembly 110. As shown in FIG 3, the frame 120 has a shape that extends along the length direction L of the cell block assembly 110, and the cross section may have a reverse U shape.

[0039] 3 and 5, the frame 120 may include, specifically, a ceiling portion 121 that encloses the other side of the cell block assembly 110, and a side wall portion 122 that encloses the side of the cell block assembly 110. Here, the ceiling portion 121 and the side wall portion 122 may be integrally formed. The battery module according to the first embodiment of the present invention may be formed by connecting the bottom plate 140 to the open one side of the frame 120 by brazing. In this manner, the frame may be connected to the bottom plate 140 by welding, and specifically, one side end of the side wall portion and both side ends of the bottom plate 140 may be connected to each other by welding. Here, the one side may refer to the lower side, for example. That is, the bottom plate may be connected to the open lower side of the frame by brazing.

[0040] 3, the battery module according to the first embodiment of the present invention may include end plates 150 to realize a battery module that is closed on all sides. The end plates 150 may be disposed on the front and rear surfaces of the cell block assembly 110, respectively. The end plates 150 may be welded to the front and rear of the frame 120, respectively, to form a rectangular parallelepiped battery module. In this case, power discharged from the cell block assembly 110 may be output to the outside of the end plates 150.

[0041] The cooling plate 130 may be coupled to one surface of the bottom plate 140 at one side of the bottom plate 140. Here, as an example, one side of the bottom plate may refer to the lower side of the bottom plate. Also, one surface of the bottom plate may refer to the lower surface of the bottom plate. The manner in which the cooling plate 130 is coupled to one surface of the bottom plate 140 may be coupling by welding, and in particular, coupling by brazing. A cooling flow path is formed in the cooling plate 130, and a coolant may circulate to cool the cell block assembly 110 and the bottom plate 140.

[0042] Fig. 4 is a cross-sectional view illustrating a method of assembling the battery module according to the first embodiment of the present invention, and Fig. 5 is a cross-sectional view illustrating an assembled state of the battery module according to the first embodiment of the present invention. When assembled in the form of Fig. 4, the frame 120 and the bottom plate 140 can be assembled in the form shown in Fig. 5.

[0043] Referring to FIG. 4, in order to assemble the battery module according to the first embodiment of the present invention, the cell block assembly 110 may be placed on the bottom plate 140 and the frame 120 may be covered thereon. The frame 120 may move in one side direction D from the other side of the cell block assembly 110 to cover the cell block assembly 110 and be coupled to the bottom plate 140. Here, one side direction may mean downward, for example. Both sides of the frame 120, particularly both ends of the side wall portion 122 in the one side direction D, may be coupled to both ends of the bottom plate 140 by welding. When the frame 120 moves in the one side direction D to cover the cell block assembly 110, the lower ends of the side wall portion 122 of the frame 120 may be inserted while being opened on both sides F, F', so that the cell block assembly 110 can be easily inserted into the frame 120. Unlike the conventional U-frame 120 shape, the shape of the bottom plate 140 does not change even when the frame 120 is opened on both sides, so that the welded portion of the cooling plate 130 welded to one side of the bottom plate 140 can be prevented from being damaged. In this way, the battery module according to embodiment 1 of the present invention can prevent breakage of welded portions of parts such as the cooling plate 130 during the insertion and assembly process of the cell block assembly 110.

[0044] In addition, even if swelling occurs as the battery is used for an extended period of time, the tensile force is received by the second plate portion 142 of the bottom plate 140, thereby preventing the risk of breakage of the brazed weld due to swelling.

[0045] Referring to FIG. 5, in the battery module according to the first embodiment of the present invention, the side wall portion 122 may include a first side wall portion 122-1 and a second side wall portion 122-2.

[0046] The first side wall portion 122-1 may be a portion of the side wall portion 122 facing the cell block assembly 110. The second side wall portion 122-2 may be a portion connected to the first side wall portion 122-1 in a stepped shape at one side of the first side wall portion 122-1 and extending in a direction toward one side of the first side wall portion 122-1. As shown in FIG 4, when two lower ends of the side wall portion 122 are opened to both sides F, F' by a tool such as a bracket, the stepped second side wall portion 122-2 may have a more advantageous shape.

[0047] Furthermore, when the side wall portion 122 is formed in a stepped shape, such as the first side wall portion 122-1 and the second side wall portion 122-2, even if swelling occurs as the battery is used for an extended period of time, the swelling can be absorbed, and the risk of breakage of the brazing weld on one surface (or the lower surface) of the bottom plate 140 can be reduced.

[0048] Also, an end of the second side wall portion 122-2 and an end of the second plate portion 142 may be joined to each other by welding W. In particular, one side end of the second side wall portion 122-2 and one side end of the second plate portion 142 may be joined to each other by welding W. More specifically, a lower end of the second side wall portion 122-2 and a lower end of the second plate portion 142 may be joined to each other by welding W. This shape may be such that the welded portion is located as far away from the cell block assembly 110 as possible.

[0049] Since the welding for joining the side wall portion 122 and the bottom plate 140 is performed by laser welding, heat may be generated at the welding position. Therefore, the farther the welding position is from the cell block assembly 110, the more the cell block assembly 110 can be prevented from being damaged by heat. The battery module according to the first embodiment of the present invention may be advantageous in this respect. That is, since welding is performed at the lower end of the second side wall portion 122-2 and the lower end of the second plate portion 142, damage to the cell block assembly 110 due to welding heat can be prevented. In addition, the shape of the second plate portion 142 extending in a vertical direction from the first plate portion 141 has the advantage of increasing the cooling area and improving cooling efficiency.

[0050] Referring to FIG. 5, the battery module according to the first embodiment of the present invention may further include an insulating film disposed between the frame 120 and the cell block assembly 110.

[0051] Specifically, the insulating film may include a horizontal portion 161 and a vertical portion 162. The horizontal portion 161 may be a portion disposed between the ceiling portion 121 and the cell block assembly 110. The vertical portion 162 may be a portion disposed between the side wall portion 122 and the cell block assembly 110. The horizontal portion 161 and the vertical portion 162 may be formed integrally. Also, the horizontal portion 161 and the vertical portion 162 may be formed in a form that is continuously connected. When the insulating film is provided in this manner, it is possible to more significantly prevent current leakage or short circuit. As an example, the insulating film may be provided in a form that is attached to the inner surface of the frame 120.

[0052] Also, the battery module according to the first embodiment of the present invention may further include a thermally conductive resin 170 disposed between the other surface (or upper surface) of the bottom plate 140 and one surface (or lower surface) of the cell block assembly 110. Heat generated in the cell block assembly 110 is transferred to the bottom plate 140 via the thermally conductive resin 170, and the heat thus transferred to the bottom plate 140 may be transferred to the cooling plate 130 for cooling. Here, the thermally conductive resin 170 may play a role in further increasing the thermal conductivity and significantly improving the cooling efficiency.

[0053] EMBODIMENT 2 FIG. 6 is a diagram illustrating a method for manufacturing a battery module according to embodiment 2 of the present invention.

[0054] The second embodiment of the present invention is different from the first embodiment in that it relates to a method for manufacturing the battery module according to the first embodiment of the present invention.

[0055] The second embodiment will be described focusing on the differences and omitting the contents common to the first embodiment as much as possible. In other words, when contents not explained in the second embodiment are necessary, it is self-evident that they can be supplemented through the contents of the first embodiment.

[0056] 4 to 6, the method for manufacturing a battery module according to embodiment 1 of the present invention includes the steps of: preparing a bottom plate 140 having a cooling plate 130 coupled to one side thereof (S01); placing a cell block assembly 110, which is an assembly of a plurality of cells, on the other side of the bottom plate 140 (S02); coupling a frame 120 to the bottom plate 140 so as to enclose the other side and side of the cell block assembly 110 (S03); and coupling end plates 150 to the front and rear of the cell block assembly 110 (S04).

[0057] In the step S01 of preparing the bottom plate 140 having the cooling plate 130 bonded to one side thereof, the cooling plate 130 may be welded to the bottom plate 140 by brazing. Here, one side may refer to the lower surface, for example. Conventionally, the cooling plate 130 has been welded to one side of the U-frame 120, but the present invention differs from the conventional form in that the cooling plate 130 may be welded to one side of the plate-shaped bottom plate 140. In this case, the volume may be significantly reduced. Accordingly, the amount of materials to be put into the heat treatment chamber may be increased, leading to cost reduction.

[0058] The step S02 of placing the cell block assembly 110 may be a step of moving the cell block assembly 110 located on the other side of the bottom plate 140 in one direction D and placing it on the other side of the bottom plate 140. Also, the step S02 of placing the cell block assembly 110 may be a step of placing the cell block assembly 110 on the other side of the bottom plate 140 with a thermal conductive resin 170 disposed between the cell block assembly 110 and the bottom plate 140. Here, the other side of the bottom plate may refer to the upper surface of the bottom plate, for example.

[0059] In the step S03 of coupling the frame 120 to the bottom plate 140, the frame 120 may move in one side direction D from the other side of the cell block assembly 110 to cover the cell block assembly 110 and be coupled to the bottom plate 140. Here, the one side direction D may mean downward, for example. Both sides of the frame 120, particularly the ends of the side walls 122 in one side direction, may be coupled to both ends of the bottom plate 140 by laser welding. When the frame 120 moves in the one side direction D to cover the cell block assembly 110, the cell block assembly 110 may be inserted into the frame 120 while opening the lower ends of the side walls 122 of the frame 120 to both sides F, F', so that the cell block assembly 110 can be easily inserted into the frame 120. While being inserted in this manner, the frame 120 may be coupled to the bottom plate 140. Also, in this step, the frame 120 having the insulating sheet 160 coupled to the inner side surface may be coupled to the bottom plate 140.

[0060] In the step of coupling the end plates (S04), the end plates 150 may be disposed on the front and rear surfaces of the cell block assembly 110. The end plates 150 may be coupled to the front and rear of the frame 120 by welding to form a rectangular parallelepiped battery module. In this case, power discharged from the cell block assembly 110 may be output to the outside of the end plates 150.

[0061] The present invention has been described above using limited embodiments 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]

[0062] 110 Cell Block Assembly 120 frames 121 Ceiling 122 Side wall 122-1 First side wall 122-2 Second side wall 130 Cooling Plate 140 Bottom Plate 141 First Plate Section 142 Second Plate Section 150 End Plate 160 Insulation sheet 161 Horizontal part 162 Vertical section 170 Thermally conductive resin W Welding

Claims

1. a cell block assembly which is an assembly of a plurality of cells; a bottom plate disposed on one side of the cell block assembly; a frame enclosing the other surface and a side surface of the cell block assembly; and end plates disposed on front and rear surfaces of the cell block assembly.

2. The battery module of claim 1 , further comprising a cooling plate coupled to one surface of the bottom plate on one side of the bottom plate.

3. The battery module according to claim 2 , wherein the cooling plate is joined to the one surface of the bottom plate by brazing.

4. The frame is a ceiling portion that encloses the other surface of the cell block assembly; The battery module according to claim 1 , further comprising a side wall portion enclosing the side surface of the cell block assembly.

5. The battery module according to claim 4 , wherein the ceiling portion and the side wall portion are integrally formed.

6. The battery module according to claim 4 , wherein one side end of the side wall portion and both side ends of the bottom plate are joined by welding.

7. The side wall portion is a first side wall portion facing the cell block assembly; The battery module of claim 6 , further comprising: a second side wall portion connected to the first side wall portion in a stepped shape at one side of the first side wall portion and extending in a direction toward the one side of the first side wall portion.

8. The bottom plate is a first plate portion extending in a direction parallel to the one surface of the cell block assembly while facing the cell block assembly; The battery module according to claim 7 , further comprising: second plate portions extending from both side ends of the first plate portion in a direction away from the cell block assembly.

9. The battery module according to claim 8 , wherein an end portion of the second side wall portion and an end portion of the second plate portion are joined to each other by welding.

10. The battery module according to claim 4 , further comprising an insulating film disposed between the frame and the cell block assembly.

11. The insulating film is a horizontal portion disposed between the ceiling portion and the cell block assembly; a vertical portion disposed between the sidewall portion and the cell block assembly; The battery module of claim 10 , wherein the horizontal portion and the vertical portion are integrally formed.

12. The battery module according to claim 2 , further comprising a thermally conductive resin disposed between the other surface of the bottom plate and the one surface of the cell block assembly.

13. providing a bottom plate having a cooling plate bonded to one side thereof; placing a cell block assembly, which is an assembly of a plurality of cells, on the other surface of the bottom plate; coupling a frame to the bottom plate so as to enclose the other surface and a side surface of the cell block assembly; and bonding end plates to front and rear surfaces of the cell block assembly.

14. The step of placing the cell block assembly includes: The method for manufacturing a battery module according to claim 13 , wherein the cell block assembly is placed on the other surface of the bottom plate with a thermally conductive resin disposed between the cell block assembly and the bottom plate.

15. The step of coupling the frame to the bottom plate comprises: The method for manufacturing a battery module according to claim 13 or 14, further comprising the step of: bonding the frame, the frame having an insulating sheet bonded to an inner side surface thereof, to the bottom plate.

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