Battery module and manufacturing method thereof

Abstract

A battery module according to one embodiment of the present invention includes a battery cell stack in which a plurality of battery cells are stacked side by side, a top frame covering an upper surface of the battery cell stack, a bus bar frame coupled to the top frame and covering a side surface of the battery cell stack, and a module frame having a square tubular shape and housing a battery cell assembly formed by combining the battery cell stack, the top frame, and the bus bar frame, wherein the top frame includes a first protrusion at one end thereof that protrudes toward an upper surface of the module frame, and the module frame includes a second protrusion at a position inside the upper surface corresponding to another end thereof located opposite to the one end of the top frame that protrudes toward the top frame.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0178455, dated December 19, 2022, and all contents disclosed in the documents of that patent application are incorporated herein by reference.

[0002] The present invention relates to a battery module and a manufacturing method thereof, and more particularly to a battery module and a manufacturing method thereof that can stabilize the positions and dimensions of components within the battery module and prevent excessive resin injection into the battery module. [Background technology]

[0003] With technological development and increasing demand for mobile devices, the demand for secondary batteries as an energy source is rapidly increasing. As a result, much research is being conducted on secondary batteries that can meet various requirements.

[0004] Secondary batteries have attracted much attention as energy sources for power plants such as electric bicycles, electric vehicles, and hybrid electric vehicles, as well as for mobile devices such as mobile phones, digital cameras, and laptop computers.

[0005] Small devices such as mobile phones and cameras use small battery packs containing a single battery cell, while medium- to large-sized devices such as laptops and electric vehicles use medium- to large-sized battery packs containing two or more battery cells connected in parallel and / or series. Therefore, the number of battery cells included in the battery pack can be set in various ways depending on the required output voltage or charge / discharge capacity.

[0006] Meanwhile, when constructing a battery pack by connecting multiple battery cells in series / parallel, a common method is to first construct a battery module consisting of at least one battery cell, and then use this at least one battery module to add other components to construct the battery pack.

[0007] In the case of such battery modules, the importance of technology that can efficiently cool the heat generated in the battery cells is increasing as the required battery capacity increases. To this end, a structure that can improve thermal conductivity by applying a resin for heat dissipation to the inside of the case of the battery module has been introduced.

[0008] Fig. 1 is a diagram showing a conventional battery module, and Fig. 2 is a diagram showing a cross section taken along line AA' in Fig. 1 flipped 180 degrees, showing the configuration excluding the end plates.

[0009] In a conventional battery module 10, the battery cell stack 11 and the combined top frame 50 and bus bar frame 30, which are respectively coupled to the top and side surfaces of the battery cell stack 11, are housed inside the module frame 20, with the bottom surface facing upward, and thermally conductive resin for heat dissipation is injected into the module frame 20. That is, as shown in Fig. 2, with the top surface 21 of the module frame 20 facing downward and the bottom surface 22 facing upward, thermally conductive resin is injected through at least one injection hole H formed in the bottom surface 22 and cured to form a thermally conductive resin layer 80.

[0010] However, during this process, a certain amount of gap is required to ensure an injection space for injecting the thermally conductive resin into the module frame 20, and as a result, there is a problem that the position of the battery cell stack 11 may become unstable due to internal flow during the time between inserting the battery cell stack 11 into the module frame 20 and forming the thermally conductive resin layer, and that this may cause the position of components coupled to the battery cell stack 11 to become unstable. Furthermore, the occurrence of deviations in the internal space causes the amount of thermally conductive resin injected to become unstable, resulting in excessive injection more than necessary, which increases costs and the weight of the battery module. Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention has been made to solve these problems, and an object of the present invention is to provide a battery module and a manufacturing method thereof that can improve the positional stability of a battery cell stack inside a module frame during the manufacturing process of the battery module, and can reduce manufacturing costs and prevent unnecessary weight increase by injecting an appropriate amount of thermally conductive resin into the module.

[0012] However, the problems to be solved by the embodiments of the present invention are not limited to the above problems, and can be variously expanded within the scope of the technical ideas included in the present invention. [Means for solving the problem]

[0013] A battery module according to one embodiment of the present invention includes a battery cell stack in which a plurality of battery cells are stacked side by side, a top frame covering an upper surface of the battery cell stack, a bus bar frame coupled to the top frame and covering a side surface of the battery cell stack, and a module frame having a square tubular shape and housing a battery cell assembly formed by combining the battery cell stack, the top frame, and the bus bar frame, wherein the top frame includes a first protrusion at one end thereof that protrudes toward an upper surface of the module frame, and the module frame includes a second protrusion at a position inside the upper surface corresponding to another end thereof located opposite to the one end of the top frame that protrudes toward the top frame.

[0014] The first protrusion and the second protrusion may have the same protrusion height.

[0015] Each of the first protrusion and the second protrusion may have an inclined shape such that the height of the protrusion decreases in a direction facing the inside of the module frame.

[0016] The battery pack may further include a thermally conductive resin layer disposed between a lower surface of the module frame and the battery cell assembly.

[0017] The bus bar frame may include an extension portion that extends along a lower surface of the battery cell stack and protrudes, and the thermally conductive resin layer may be positioned inside the extension portion.

[0018] The one end and the other end may be both longitudinal end portions of the top frame, and two or more of the first protrusions and the second protrusions may be arranged along a width direction perpendicular to the longitudinal direction.

[0019] A method for manufacturing a battery module according to another embodiment of the present invention includes forming a battery cell assembly by combining a battery cell stack in which a plurality of battery cells are stacked adjacent to one another, a top frame covering an upper surface of the battery cell stack, and a bus bar frame coupled to the top frame and covering a side surface of the battery cell stack; and inserting the battery cell assembly into a module frame having a square tubular shape, wherein the top frame includes a first protrusion at one end of the top frame that protrudes toward an upper surface of the module frame, and the module frame includes a second protrusion that protrudes toward an inside of the module frame at a position corresponding to another end of the inner side of the upper surface that is opposite to the one end of the top frame, and the inserting of the battery cell assembly is performed with the top frame and the upper surfaces of the module frame facing downward in the direction of gravity, and includes inserting the other end of the top frame toward the second protrusion.

[0020] The first protrusion and the second protrusion may have the same protrusion height.

[0021] The method may further include, after the step of inserting the battery cell assembly, injecting and curing a thermally conductive resin between the battery cell assembly and a lower surface of the module frame, wherein the battery cell assembly is supported by the first protrusion and the second protrusion during the step of injecting and curing the thermally conductive resin.

[0022] Each of the first protrusion and the second protrusion may have an inclined shape such that the height of the protrusion decreases in a direction facing the inside of the module frame, and in the step of inserting the battery cell assembly, the other end of the top frame may be inserted along the inclined shape of the second protrusion.

[0023] A battery pack according to yet another embodiment of the present invention may include the at least one battery module. [Effects of the Invention]

[0024] According to the embodiments, it is possible to provide a battery module and a manufacturing method thereof that can improve the positional stability of the battery cell stack inside the module frame during the manufacturing process of the battery module, and can reduce manufacturing costs and prevent unnecessary weight increase by injecting an appropriate amount of thermally conductive resin into the module.

[0025] The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 is a diagram showing a conventional battery module. [Figure 2] FIG. 2 is a cross-sectional view taken along the line AA' in FIG. 1, turned over by 180 degrees, showing the configuration excluding the end plates. [Figure 3] 1 is a diagram showing a battery module according to an embodiment of the present invention; [Figure 4] FIG. 4 is a diagram showing the battery module of FIG. 3 in an exploded state. [Figure 5] 4 is a cross-sectional view taken along the line BB' in FIG. 3, turned over by 180 degrees, showing the configuration excluding the end plates. [Figure 6] 10A to 10C are views schematically illustrating a process of inserting a battery cell assembly into a module frame in a method of manufacturing a battery module according to another embodiment of the present invention. [Figure 7] 7 is a diagram following FIG. 6, showing a schematic diagram of a process of completing a battery module by injecting a thermally conductive resin layer into the battery module. DETAILED DESCRIPTION OF THE INVENTION

[0027] The present invention may be embodied in various different forms and is not limited to the embodiments set forth herein.

[0028] In order to clearly explain the present invention, parts not necessary for the explanation will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0029] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for the convenience of explanation, and the present invention is not necessarily limited to those shown in the drawings. In the drawings, thicknesses are exaggerated to clearly show various layers and regions. In the drawings, thicknesses of some layers and regions are exaggerated for the convenience of explanation.

[0030] Furthermore, when a layer, film, region, plate, or other part is said to be "above" another part, this does not only mean that it is "directly above" that part, but also includes cases where there is another part in between. Conversely, when a part is said to be "directly above" another part, it means that there is no other part in between. Furthermore, being "above" a reference part means being located above or below the reference part, and does not necessarily mean being "above" in the opposite direction of gravity.

[0031] Furthermore, throughout the specification, when a part is described as "comprising" a certain element, this does not mean that it can further include other elements, unless otherwise specified.

[0032] Furthermore, throughout the specification, "in a plane" means a view of the subject matter as viewed from above, and "in cross section" means a view of the subject matter as viewed from the side across a vertical cross section.

[0033] Hereinafter, a battery module according to an embodiment of the present invention will be described with reference to FIGS.

[0034] FIG. 3 is a diagram showing a battery module according to one embodiment of the present invention, FIG. 4 is a diagram showing the battery module of FIG. 3 in an exploded state, and FIG. 5 is a diagram showing a cross section along B-B' of FIG. 3 flipped 180 degrees, showing the configuration excluding the end plates.

[0035] 3 to 5, a battery module 100 according to an embodiment of the present invention includes a battery cell stack 110 in which battery cells are stacked, a top frame 500 that covers the upper surface of the battery cell stack 110, and a bus bar frame 300 that is coupled to the top frame 500 and covers the side surface of the battery cell stack 110. The battery module 100 also includes a module frame 200 that houses a battery cell assembly 400 formed by combining the battery cell stack 110, the top frame 500, and the bus bar frame 300.

[0036] The battery cell stack 110 is an assembly of secondary batteries including a plurality of battery cells. The battery cell stack 110 may include a plurality of battery cells, each of which includes an electrode lead (not shown). The battery cells may be, but are not limited to, pouch-type battery cells having a plate shape. The electrode lead may be a positive electrode lead or a negative electrode lead, and the end of the electrode lead of each battery cell may be bent in one direction so as to abut against the end of the electrode lead of an adjacent battery cell. The two abutting electrode leads may be fixed to each other by welding or the like, thereby establishing electrical connection between the battery cells within the battery cell stack 110.

[0037] A plurality of battery cells are vertically stacked with their electrode leads aligned in one direction (the +X and −X directions in the drawing) to form a battery cell stack 110. The electrode leads aligned in one direction can be electrically connected to a bus bar fixed to a bus bar frame 300 arranged to cover the battery cell stack 110. That is, the bus bar frame 300 is made of an insulator and includes lead slots through which the electrode leads drawn out from the battery cell stack 110 can pass, and the bus bar can electrically connect the electrode leads 112 of the battery cell stack 110.

[0038] Various other electrical components may be attached to the bus bar frame 300. For example, an internal circuit board (ICB) and a battery management system (BMS) may be provided, and the electrical components such as the ICB and BMS board may be electrically connected to the plurality of battery cells.

[0039] The top frame 500 is positioned on top of the battery cell stack 110, and bus bar frames 300 are rotatably coupled to both side surfaces of the top frame 500. The bus bars are attached to the bus bar frame 300, and a flexible printed circuit board (FPCB) is disposed at the top end of the top frame 500 along the longitudinal direction. The flexible printed circuit board is electrically connected to the bus bars, thereby enabling sensing of overvoltage and overcurrent of the battery cells, and a connector is connected to one end of the flexible printed circuit board so that signals related to voltage sensing and temperature sensing can be transmitted to and received from a controller installed outside the battery module 100.

[0040] The bus bar frame 300 includes an extension 310 that extends and protrudes from the lower end along the lower surface of the battery cell stack 110. This allows the side surface of the bus bar frame 300 in Fig. 4 to have an L-shape. The inclusion of the extension 310 protects the corners of the battery cell stack 110, which have weak rigidity, and prevents the corners of the battery cell stack 110 from being damaged.

[0041] A top frame 500 is placed on the top surface of the battery cell stack 110, and a bus bar frame 300 rotatably coupled to the top frame 500 is rotated and coupled to a side of the battery cell stack 110 on which electrode leads are formed, thereby forming a battery cell assembly 400. The battery cell assembly 400 is housed in a module frame 200 having a rectangular tubular shape and including four plates that surround at least four sides of the battery cell stack 110 and at least one opening that opens in the longitudinal direction of the battery cell stack 110. That is, the module frame 200 may include a lower surface 202, an upper surface 201 facing the lower surface 202, and two side surfaces 203 connecting the upper surface 201 and the lower surface 202. Meanwhile, when the battery cell assembly 400 is housed in the module frame 200, the bus bar frame 300 is exposed through the opening in the module frame 200, and the opening may be covered by an end plate 600.

[0042] A thermally conductive resin layer 800 is positioned between the lower surface of the battery cell stack 110 and the lower surface of the module frame 200. The thermally conductive resin layer 800 is made of a thermally conductive material, such as a thermal resin, to dissipate heat generated from the battery cell stack 110 to the outside. Examples of such thermal resins include silicone, urethane, and epoxy. The thermally conductive resin layer 800 not only transfers the generated heat to the bottom of the battery module 100 but also fixes the battery cell stack 110 within the battery module 100. The thermally conductive resin layer 800 can be formed by curing a thermally conductive resin injected in a liquid state through holes H formed in the lower surface of the module frame 200. The thermally conductive resin layer 800 obtained in this manner may be disposed between the battery cell assembly 400 and the lower surface 202 of the module frame 200, inside the extension portion 310 of the bus bar frame 300, as shown in FIG. 5.

[0043] An expansion control pad 700 may be provided between the side of the battery cell stack 110 and the module frame 200. The expansion control pad 700 is compressed to provide a cushioning effect when the battery cells expand, thereby controlling cell swelling and preventing damage to the battery cells and module frame 200 due to the expansion of the battery cells. To this end, the expansion control pad 700 may include a soft, elastic material such as polyurethane (PU) or EPDM (Ethylene Propylene Diene Monomer). Such materials have excellent vibration absorption and compression resilience, and therefore can guide the battery module 100 to have excellent dimensional stability even when cell swelling occurs in multiple battery cells.

[0044] Meanwhile, the top frame 500 includes a first protrusion 510 protruding from one end of the top frame 500 toward the module frame 200. Here, the one end refers to either end in the longitudinal direction of the top frame 500, i.e., in the direction aligned with the X-axis in the figure, for example, the +X end in the figure. The first protrusion 510 is formed to protrude toward the upper surface 201 of the module frame 200. That is, it protrudes upward in the Z-axis direction in the figure. Two or more first protrusions 510 may be provided, and in this case, they may be spaced apart from each other in the width direction perpendicular to the longitudinal direction of the top frame 500, i.e., in the direction aligned with the Y-axis in the figure. The first protrusion 510 may have a sloped shape at an end facing inward of the module frame 200, decreasing in height as it faces inward. This prevents damage to components when inserting a battery cell assembly 400, as described below.

[0045] The module frame 200 includes a second protrusion 210 on the inner side of the upper surface 201. The second protrusion 210 is formed at a position corresponding to the other end opposite to the end where the first protrusion 510 is formed. That is, the second protrusion 210 is disposed at a position corresponding to the -X side end in the figure, and protrudes from the inner side of the upper surface 201 toward the inside of the module frame 200. The second protrusion 210 is formed to have the same height as the first protrusion 510. In addition, the second protrusion 210 may have a sloped shape at the end facing the inside of the module frame 200, with its height decreasing as it faces inward.

[0046] The first protrusion 510 and the second protrusion 210 can be set within a range that ensures space for accommodating components included in the battery cell assembly 400 while also ensuring space for forming the thermally conductive resin layer 800 within the module frame 200 during the manufacture of the battery module 100. In other words, the battery cell assembly 400 occupies most of the space within the battery module 100, but it needs to be stably positioned in a predetermined position, particularly in the Z-axis direction, to accommodate other components and the thermally conductive resin layer 800. Conventionally, however, there has been a problem of the battery cell assembly becoming misaligned if it is turned upside down during the manufacturing process. However, according to this embodiment, the position of the battery cell assembly 400 can be restricted by the first and second protrusions, preventing the battery cell assembly 400 from becoming unstable. Furthermore, as will be described later, the amount of thermally conductive resin injected to form the thermally conductive resin layer 800 can be uniformly and appropriately injected, preventing increases in weight and cost due to excessive injection.

[0047] Next, a method for manufacturing a battery module according to another embodiment of the present invention will be described with reference to FIGS.

[0048] FIG. 6 is a diagram schematically illustrating a process of inserting a battery cell assembly into a module frame in a method of manufacturing a battery module according to another embodiment of the present invention, and FIG. 7 is a diagram schematically illustrating a process of completing the battery module by injecting a thermally conductive resin layer into the battery module, following FIG. 6 .

[0049] 6(a), a battery cell assembly 400 is formed by combining a battery cell stack 110, a top frame 500 that covers the upper surface of the battery cell stack 110, and a bus bar frame 300 that is combined with the top frame 500 and covers the side surface of the battery cell stack 110. The battery cell assembly 400 is inserted into a module frame 200, whose upper surface 201 is similarly arranged at the bottom, with the top frame 500 arranged at the bottom.

[0050] The battery cell assembly 400 may be inserted into the module frame 200 from the other end of the top frame 500, i.e., the end where the first protrusion 510 is not formed, in a direction toward the end of the module frame 200 where the second protrusion 210 is formed. During the insertion process, a distance d equal to the height of the first and second protrusions 510, 210 may be maintained between the upper surface 201 and the battery cell assembly 400. Furthermore, the battery cell assembly 400 may be inserted along the inclined shape of the second protrusion 210 and placed on the second protrusion 210. During this process, because the battery cell assembly 400 is inserted along the inclined shape, damage due to interference between components during the insertion process may be prevented. In addition, the first protrusion 510 formed at one end of the battery cell assembly 400 also has a sloped shape that decreases in height as it faces inward, so that the end of the module frame 200 can be coupled along the sloped shape during insertion, thereby preventing the module frame 200 and the top frame 500 from being damaged during the insertion process.

[0051] By inserting the battery cell assembly 400 in this manner, a configuration can be obtained in which the battery cell assembly 400 is placed inside the module frame 200 while maintaining a gap between only the first and second protrusions 510, 210, as shown in Figure 6 (c).

[0052] Next, as shown in FIG. 7, a step of injecting a thermally conductive resin into the interior of the module is carried out.

[0053] The thermally conductive resin is injected through the injection holes H formed in the lower surface 202 of the module frame 200 when the module is inverted, with the lower surface 202 facing upward. Although the module is inverted, the battery cell assemblies 400 are supported by the first and second protrusions 510 and 210, allowing a desired gap to be maintained between the battery cell assemblies 400 and the upper surface 201. Furthermore, the space into which the thermally conductive resin is injected can be maintained at an appropriate distance without fluctuation. In other words, when the injection process is performed with the module inverted, gravity forces the internal battery cell assemblies 400 to be positioned without any gap from the upper surface, creating a larger injection space than necessary and unnecessarily increasing the amount of thermally conductive resin injected. Furthermore, the position of the battery cell assemblies 400 is not fixed before the thermally conductive resin hardens, which can cause vertical fluctuations. However, according to this embodiment, it is possible to prevent positional fluctuations of the battery cell assembly 400 that may occur during the injection process, and by fixing the position of the battery cell assembly 400 in the vertical direction, it is possible to maintain the desired spatial dimensions between the upper and lower surfaces of the module frame 200. Therefore, it is possible to stabilize the quality of the component dimensions of the battery module, and to prevent increases in weight and costs due to excessive injection of thermally conductive resin.

[0054] After the thermally conductive resin has been poured and cured, the battery module 100 is again turned over so that the upper components face upward, as shown in FIG. 7(b).

[0055] As described above, when inserting the battery cell assembly 400 into the module frame 200, the first protrusion 510 is formed on the top frame 500, and the second protrusion 210 having the same height as the first protrusion 510 is formed on the inside of the upper surface 201 of the module frame 200. This makes it possible to maintain the intended spacing between the battery cell assembly 400 and the module frame 200, thereby providing a method for manufacturing a battery module 100 that ensures dimensional stability of the parts while preventing over-injection of thermally conductive resin.

[0056] Meanwhile, one or more battery modules according to the embodiments of the present invention may be packaged in a pack case to form a battery pack.

[0057] The above-described battery module and battery pack including the same can be applied to various devices, including transportation means such as electric bicycles, electric cars, and hybrid cars, but the present invention is not limited thereto and can be applied to various devices that can use a battery module and a battery pack including the same, which also fall within the scope of the present invention.

[0058] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention. [Explanation of symbols]

[0059] 100: Battery module 110: Battery cell stack 200:Module frame 300: Busbar frame 400: Battery cell assembly 500: Top frame 510: 1st protrusion 210:Second protrusion

Claims

1. a battery cell stack in which a plurality of battery cells are stacked side by side adjacent to one another; a top frame covering the top surface of the battery cell stack; a bus bar frame coupled to the top frame and covering a side surface of the battery cell stack; a module frame having a square tubular shape and configured to house a battery cell assembly formed by combining the battery cell stack, the top frame, and the bus bar frame; Including, the top frame includes a first protrusion protruding from one end of the top frame toward an upper surface of the module frame, The module frame includes a second protrusion protruding toward the top frame at a position corresponding to the other end of the top frame located opposite to the one end of the top frame on the inner side of the upper surface.

2. The battery module of claim 1 , wherein the first protrusion and the second protrusion have the same protrusion height.

3. The battery module according to claim 1 , wherein each of the first protrusion and the second protrusion has an inclined shape such that the height of the protrusion decreases in a direction facing the inside of the module frame.

4. The battery module according to claim 1 , further comprising a thermally conductive resin layer disposed between the lower surface of the module frame and the battery cell assembly.

5. the bus bar frame includes an extension portion that extends and protrudes along a lower surface of the battery cell stack; The battery module according to claim 4 , wherein the thermally conductive resin layer is located inside the extension portion.

6. The one end and the other end are both end portions of the top frame in the longitudinal direction, The battery module according to claim 1 , wherein two or more of the first protrusions and two or more of the second protrusions are arranged along a width direction perpendicular to the longitudinal direction.

7. forming a battery cell assembly by combining a battery cell stack in which a plurality of battery cells are stacked adjacent to one another in a row, a top frame covering an upper surface of the battery cell stack, and a bus bar frame coupled to the top frame and covering a side surface of the battery cell stack; inserting the battery cell assembly into a module frame having a square tubular shape; Including, the top frame includes a first protrusion protruding from one end of the top frame toward an upper surface of the module frame, the module frame includes a second protrusion protruding toward an inside of the module frame at a position corresponding to another end of the top frame opposite to the one end of the top frame on an inside of the upper surface, the inserting of the battery cell assembly is performed in a state in which upper surfaces of the top frame and the module frame are arranged to face downward in a direction of gravity, and the other end of the top frame is inserted toward the second protrusion.

8. The method of manufacturing a battery module according to claim 7 , wherein the first protrusion and the second protrusion have the same protrusion height.

9. the method further includes, after the step of inserting the battery cell assembly, injecting a thermally conductive resin between the battery cell assembly and a lower surface of the module frame and curing the resin; The method of manufacturing a battery module according to claim 7 or 8, wherein the battery cell assembly is supported by the first protrusion and the second protrusion during the injecting and curing of the thermally conductive resin.

10. each of the first protrusion and the second protrusion has an inclined shape such that the height of the protrusion decreases in a direction facing the inside of the module frame; The method of claim 7 , wherein, in the inserting the battery cell assembly, the other end of the top frame is inserted along the inclined shape of the second protrusion.

11. A battery pack comprising at least one battery module according to claim 1.

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