Battery module and method for manufacturing the same

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 of related applications This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0178455 filed on December 19, 2022, and all the contents disclosed in the literature of the patent application are incorporated herein by reference.

[0002] The present invention relates to a battery module and a method for manufacturing the same, and more particularly, to a battery module and a method for manufacturing the same that can stabilize the position and dimensions of components in the battery module and prevent excessive resin injection in the battery module.

Background Art

[0003] With the development of technology and the increasing demand for mobile devices, the demand for secondary batteries as an energy source has been rapidly increasing. Accordingly, many studies have been conducted on secondary batteries that can meet various requirements.

[0004] Secondary batteries have attracted much attention not only as an energy source for mobile devices such as mobile phones, digital cameras, and notebook computers, but also as an energy source for power devices such as electric bicycles, electric vehicles, and hybrid electric vehicles.

[0005] Small battery packs in which one battery cell is packed are used for small devices such as mobile phones and cameras, while medium or large battery packs in which two or more battery cells are connected in parallel and / or in series are packed for medium or large devices such as notebook computers and electric vehicles. Therefore, the number of battery cells included in the battery pack can be variously set according to the required output voltage or charge / discharge capacity.

[0006] On the other hand, when configuring a battery pack by connecting multiple battery cells in series or parallel, it is common practice to first configure a battery module consisting of at least one battery cell, and then use this at least one battery module to add other components and configure the battery pack.

[0007] In the case of such battery modules, the increasing demand for battery capacity has made the importance of technologies that can efficiently cool the heat generated in the battery cells increasingly significant. For this reason, a structure has been introduced in the battery module that allows for improved thermal conductivity by applying a heat-dissipating resin to the inside of the case.

[0008] Figure 1 shows a conventional battery module. Figure 2 shows a cross-section along line A-A' in Figure 1, rotated 180 degrees, illustrating the configuration excluding the end plate.

[0009] In conventional battery modules 10, a battery cell stack 11 and a top frame 50 and busbar frame 30 assembly, which connect to the top and side surfaces of the battery cell stack 11 respectively, are housed inside the module frame 20, with the bottom surface facing upwards, and a heat-conductive resin for heat dissipation is injected. That is, as shown in Figure 2, with the top surface 21 of the module frame 20 facing downwards and the bottom surface 22 facing upwards, a heat-conductive resin is injected through at least one injection hole H formed in the bottom surface 22, and this is cured to form a heat-conductive resin layer 80.

[0010] However, in this process, a certain amount of gap is required to secure injection space for injecting the thermally conductive resin into the module frame 20. As a result, after inserting the battery cell stack 11 into the module frame 20, the position of the battery cell stack 11 becomes unstable due to internal flow during the time until the thermally conductive resin layer is formed, and the position of components connected to the battery cell stack 11 may also become unstable. Furthermore, the occurrence of deviations in the internal space leads to instability in the amount of thermally conductive resin injected, resulting in excessive injection, which increases costs and the weight of the battery module. [Overview of the project] [Problems that the invention aims to solve]

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

[0012] However, the problems that the embodiments of the present invention aim to solve are not limited to those described above, and can be broadly extended 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 adjacent to each other, a top frame covering the upper surface of the battery cell stack, a busbar frame coupled to the top frame and covering the sides of the battery cell stack, and a rectangular tubular module frame that houses a battery cell assembly formed by coupling the battery cell stack, the top frame, and the busbar frame, wherein the top frame includes a first projection at one end of the top frame that protrudes toward the upper surface of the module frame, and the module frame includes a second projection on the inside of the upper surface that protrudes toward the top frame at a position corresponding to the other end located opposite to the one end of the top frame.

[0014] The protruding heights of the first and second protrusions may be the same.

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

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

[0017] The busbar frame includes an extension that extends and protrudes along the lower surface of the battery cell stack, and the thermally conductive resin layer may be located inside the extension.

[0018] The first end and the other end are the longitudinal ends of the top frame, and the first and second protrusions may each be arranged in pairs or more along the width direction perpendicular to the longitudinal direction.

[0019] A method for manufacturing a battery module according to another embodiment of the present invention includes the steps of forming a battery cell assembly by combining a battery cell stack in which a plurality of battery cells are stacked adjacent to each other, a top frame covering the upper surface of the battery cell stack, and a busbar frame coupled to the top frame and covering the side surface of the battery cell stack, and inserting the battery cell assembly into a module frame having a rectangular tubular shape, wherein the top frame includes a first projection at one end of the top frame that protrudes toward the upper surface of the module frame, and the module frame includes a second projection at a position corresponding to the other end located on the inside of the upper surface opposite to the one end of the top frame that protrudes toward the inside of the module frame, and the step of inserting the battery cell assembly is performed with the top frame and the upper surface of the module frame positioned so that they face downward in the direction of gravity, and includes the step of inserting the other end of the top frame toward the second projection.

[0020] The protruding heights of the first and second protrusions may be the same.

[0021] The step of inserting the battery cell assembly further includes injecting a thermally conductive resin between the battery cell assembly and the lower surface of the module frame and curing it, wherein the battery cell assembly may be 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 and second protrusions has a slanted shape such that the height of the protrusion decreases in the direction facing the inside of the module frame, and when inserting the battery cell assembly, the other end of the top frame may be inserted along the slanted 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 an embodiment, it is possible to provide a battery module and a method for manufacturing the same, which can improve the positional stability of a battery cell laminate inside a module frame during the manufacturing process of the battery module, and can also inject an appropriate amount of a thermally conductive resin into the module to reduce the cost of the manufacturing process and prevent unnecessary weight increase.

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

Brief Description of the Drawings

[0026] [Figure 1] It is a diagram showing a conventional battery module. [Figure 2] It is a diagram showing a cross-section along A-A' of FIG. 1 turned over by 180 degrees, showing a configuration excluding an end plate. [Figure 3] It is a diagram showing a battery module according to an embodiment of the present invention. [Figure 4] It is a diagram showing a state in which the battery module of FIG. 3 is disassembled. [Figure 5] It is a diagram showing a cross-section along B-B' of FIG. 3 turned over by 180 degrees, showing a configuration excluding an end plate. [Figure 6] It is a diagram schematically showing a process of inserting a battery cell assembly into a module frame among methods for manufacturing a battery module according to another embodiment of the present invention. [Figure 7] Following FIG. 6, it is a diagram schematically showing a process of injecting a thermally conductive resin layer into a battery module to complete the battery module.

Modes for Carrying Out the Invention

[0027] Hereinafter, referring to the attached drawings, various embodiments of the present invention will be described in detail so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement them. The present invention can be realized in various different forms and is not limited to the embodiments described here.

[0028] To clearly explain the present invention, descriptive parts that are unnecessary have been omitted, and the same or similar reference numerals are used throughout the specification for identical or similar components.

[0029] Furthermore, the dimensions and thicknesses of each component shown in the drawings are arbitrary for the sake of explanation, and therefore the present invention is not necessarily limited to those shown. In the drawings, the thicknesses are shown enlarged to clearly represent various layers and regions. Also, in the drawings, the thicknesses of some layers and regions are shown exaggerated for the sake of explanation.

[0030] Furthermore, when we say that a layer, membrane, region, plate, or other part is "on top" of another part, this includes not only the case where it is "directly above" the other part, but also the case where the other part is in between. Conversely, when we say that one part is "directly above" another part, it means that there is no other part in between. Also, being "on top" of a reference part means being located above or below the reference part, and does not necessarily mean being located "up" in the opposite direction of gravity.

[0031] Furthermore, when a specification states that a certain part "includes" a certain component, unless otherwise specified, this means that it can further encompass other components rather than excluding them.

[0032] Furthermore, throughout the specification, "on a plane" means when the subject is viewed from above, and "on a cross-section" means when the subject is viewed from the side of a cross-section obtained by cutting the subject perpendicularly.

[0033] A battery module according to one embodiment of the present invention will be described below with reference to Figures 3 to 5.

[0034] Figure 3 shows a battery module according to one embodiment of the present invention, Figure 4 shows the battery module of Figure 3 in a disassembled state, and Figure 5 shows a cross-section along B-B' of Figure 3 rotated 180 degrees, showing the configuration excluding the end plate.

[0035] Referring to Figures 3 to 5, a battery module 100 according to one 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 busbar frame 300 that is coupled to the top frame 500 and covers the sides of the battery cell stack 110. The module is configured to house such a battery cell stack 110, a battery cell assembly 400 formed by coupling the top frame 500 and the busbar frame 300, and a module frame 200 that houses the battery cell assembly 400.

[0036] The battery cell stack 110 is an assembly of secondary batteries containing a plurality of battery cells. The battery cell stack 110 may contain a plurality of battery cells, and each battery cell includes an electrode lead (not shown). The battery cells may be, but are not limited to, pouch-type battery cells having a plate-like shape. The electrode leads are either positive electrode leads or negative electrode leads, and the ends of the electrode leads of each battery cell can be bent in one direction, thereby allowing them to come into contact with the ends of the electrode leads of other adjacent battery cells. Two electrode leads that come into contact with each other can be fixed to each other by welding or the like, thereby providing an electrical connection between the battery cells inside the battery cell stack 110.

[0037] Multiple battery cells are stacked vertically so that their electrode leads are aligned in one direction (+X and -X directions in the drawing) to form a battery cell stack 110. The unilaterally aligned electrode leads can be electrically connected to busbars fixed to a busbar frame 300 positioned to cover the battery cell stack 110. In other words, the busbar frame 300 is made of an insulator and includes lead slots through which the electrode leads drawn from the battery cell stack 110 can pass, and the busbars can electrically connect the electrode leads 112 of the battery cell stack 110.

[0038] Various other electrical components can be attached to the busbar frame 300. For example, an ICB (Internal Circuit Board) and a BMS (Battery Management System) may be provided, and these electrical components, such as the ICB and BMS boards, can be electrically connected to the multiple battery cells.

[0039] The top frame 500 is located on top of the battery cell stack 110, and the busbar frame 300 is rotatably coupled to both sides of it. At this time, the busbars are mounted on the busbar frame 300, and the Flexible Printed Circuit Board (FPCB) is positioned at the upper end along the longitudinal direction of the top frame 500. The Flexible Printed Circuit Board is electrically connected to the busbars, thereby enabling sensing of overvoltage and overcurrent of the battery cells, and a connector is connected to one end thereof, allowing it to send and receive signals related to voltage sensing and temperature sensing to a controller located outside the battery module 100.

[0040] The busbar frame 300 includes an extension 310 that extends and protrudes from its lower end along the lower surface of the battery cell stack 110. This allows the side shape of the busbar frame 300 in Figure 4 to be L-shaped. By including the extension 310, the corner portion of the battery cell stack 110, which has weak rigidity, can be protected, preventing damage to the corner portion of the battery cell stack 110.

[0041] A top frame 500 is placed on the upper surface of the battery cell stack 110, and a busbar frame 300, which is rotatably coupled to the top frame 500, is rotated to connect to the side surface of the battery cell stack 110 where the electrode leads are formed, thereby forming a battery cell assembly 400. Such a battery cell assembly 400 is housed in a rectangular tubular module frame 200 which has at least one opening that is open in the longitudinal direction of the battery cell stack 110 and includes four plates that surround at least four surfaces of the battery cell stack 110. That is, the module frame 200 may be configured to include a lower surface 202, an upper surface 201 opposite the lower surface 202, and two side surfaces 203 that connect the upper surface 201 and the lower surface 202. On the other hand, with the battery cell assembly 400 housed in the module frame 200, the busbar 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 located 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 that can release the heat generated from the battery cell stack 110 to the outside, and may be made of, for example, thermal resin. Examples of such thermal resins include silicone, urethane, and epoxy. The thermally conductive resin layer 800 also plays a role in transferring the heat thus generated to the bottom of the battery module 100, as well as fixing 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 that has been injected in a liquid state through a hole H formed in the lower surface of the module frame 200. The thermally conductive resin layer 800 thus obtained may be placed inside the extension 310 of the busbar frame 300, between the battery cell assembly 400 and the lower surface 202 of the module frame 200, as shown in Figure 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 can control cell swelling by compressing and cushioning when the battery cells expand, thereby preventing damage to the battery cells and module frame 200 due to the expansion of the battery cells. For this purpose, the expansion control pad 700 may include a material containing a soft elastic material such as polyurethane (PU) or EPDM (Ethlene Propylene Diene Monomer). Since such materials have excellent vibration absorption and compression rebound force, they can guide the provision of a battery module 100 with excellent dimensional stability even when cell swelling occurs in multiple battery cells.

[0044] On the other hand, the top frame 500 includes a first projection 510 that protrudes toward the module frame 200 from one end of the top frame 500. In this case, the one end refers to either end of the top frame 500 in the longitudinal direction, that is, in the direction aligned with the X-axis in the figure, for example, the +X side end in the figure. The first projection 510 is formed to protrude toward the upper surface 201 of the module frame 200. That is, it protrudes toward the upper part in the Z-axis direction in the figure. Furthermore, there may be two or more first projections 510, in which case they may be spaced apart from each other in the width direction perpendicular to the longitudinal direction of the top frame 500, that is, in the direction aligned with the Y-axis in the figure. The first projection 510 may have an inclined shape at the end facing inward toward the module frame 200, with the height decreasing as it faces inward. This prevents damage to components when inserting the battery cell assembly 400, as will be described later.

[0045] The module frame 200 includes a second projection 210 on the inside of its upper surface 201. The second projection 210 is formed at a position corresponding to the other end opposite to the end on which the first projection 510 is formed. In other words, the second projection 210 is positioned at the -X side end in the figure and protrudes from the inside of the upper surface 201 toward the interior of the module frame 200. Such a second projection 210 is formed to have the same height as the first projection 510. Furthermore, the second projection 210 may have an inclined shape at the end facing inward of the module frame 200, with the height decreasing as it faces inward.

[0046] At this time, the first protrusion 510 and the second protrusion 210 can be set within a range that ensures space for accommodating components in the battery cell assembly 400, while also ensuring space for forming the thermal conductive resin layer 800 inside the module frame 200 during the manufacturing of the battery module 100. In other words, although the battery cell assembly 400 occupies most of the space inside the battery module 100, it needs to be positioned stably in a location determined for the provision of other components and the thermal conductive resin layer 800, particularly in the Z-axis direction. Conventionally, if the assembly was inverted during the manufacturing process, there was a problem of the position of the battery cell assembly shifting. However, according to this embodiment, the position of the battery cell assembly 400 can be controlled by the first and second protrusions, thus preventing positional instability of the battery cell assembly 400. Furthermore, as will be described later, the amount of thermal conductive resin injected for forming the thermal conductive resin layer 800 can be uniformly injected, preventing an increase in weight and cost due to over-injection.

[0047] Next, with reference to Figures 6 and 7, a method for manufacturing a battery module according to another embodiment of the present invention will be described.

[0048] Figure 6 is a schematic diagram showing the process of inserting a battery cell assembly into a module frame in another embodiment of the present invention for manufacturing a battery module, and Figure 7 is a schematic diagram showing the process of injecting a thermally conductive resin layer into the battery module to complete the battery module, following Figure 6.

[0049] As shown in Figure 6(a), the battery cell stack 110, the top frame 500 covering the top surface of the battery cell stack 110, and the busbar frame 300 coupled to the top frame 500 and covering the sides of the battery cell stack 110 are joined to form a battery cell assembly 400. The battery cell assembly 400 is inserted into the module frame 200, with the top frame 500 positioned at the bottom and the top surface 201 positioned at the bottom.

[0050] The battery cell assembly 400 is inserted into the module frame 200 from the other end of the top frame 500, that is, the end where the first protrusion 510 is not formed, and at this time, it may be inserted in the direction toward the end of the module frame 200 where the second protrusion 210 is formed. During the insertion process, a gap d equal to the height of the first and second protrusions 510 and 210 can be maintained between the top surface 201 and the battery cell assembly 400. Alternatively, the battery cell assembly 400 may be inserted along the inclined shape of the second protrusion 210 and placed on the second protrusion 210. In this process, since the battery cell assembly 400 is inserted along the inclined shape, damage due to interference between parts during the insertion process can be prevented. Furthermore, the first projection 510 formed at one end of the battery cell assembly 400 also has an inclined shape that decreases in height as it faces inward. Therefore, when inserted, the end of the module frame 200 can be joined along this inclined shape, thereby preventing damage to the module frame 200 and the top frame 500 during the insertion process.

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

[0052] Next, as shown in Figure 7, the process of pouring a thermally conductive resin into the inside of the module is carried out.

[0053] The thermal conductive resin is injected through injection holes H formed in the lower surface 202 of the module frame 200, while the module frame 200 is inverted with its lower surface 202 facing upwards. At this time, although the module is inverted, the battery cell assembly 400 is supported by the first and second protrusions 510 and 210, so that the desired distance can be maintained between the battery cell assembly 400 and the upper surface 201. In addition, the space in which the thermal 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, conventionally, the internal battery cell assembly 400 is forced to be positioned without any distance from the upper surface due to gravity, and in this case, more injection space than necessary is generated, resulting in an unnecessary increase in the amount of thermal conductive resin injected. Furthermore, before the thermal conductive resin hardens, the position of the battery cell assembly 400 is not fixed, so vertical fluctuations may occur. However, according to this embodiment, it is possible to prevent positional fluctuations of the battery cell assembly 400 that may occur during the liquid injection process, and by fixing the position of the battery cell assembly 400 in the vertical direction, the desired spatial dimensions can be maintained between it and the upper and lower surfaces of the module frame 200. Therefore, the quality of the component dimensions of the battery module can be stabilized, and increases in weight and cost due to excessive injection of thermally conductive resin can be prevented.

[0054] After the thermally conductive resin is poured in and hardened, the battery module 100 is inverted again as shown in Figure 7(b) so that the upper components face upwards.

[0055] As described above, when inserting the battery cell assembly 400 into the module frame 200, a first protrusion 510 is formed on the top frame 500, and a 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 components while simultaneously preventing over-injection of thermally conductive resin.

[0056] On the other hand, one or more battery modules according to the embodiment of the present invention can be packaged in a pack case to form a battery pack.

[0057] The battery modules and battery packs containing them described above are applicable to a variety of devices. Such devices can be used as means of transport, such as electric bicycles, electric vehicles, and hybrid vehicles, but the present invention is not limited thereto and is applicable to a variety of devices that can use the battery modules and battery packs containing them, and this also falls within the scope of the present invention.

[0058] Although 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 by those skilled in the art that utilize the basic concepts of the present invention as 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 multiple battery cells are stacked side by side adjacent to each other, A top frame covering the upper surface of the aforementioned battery cell stack, A busbar frame coupled to the top frame and covering the side surface of the battery cell stack, A module frame having a rectangular tubular shape houses the battery cell assembly formed by connecting the battery cell stack, the top frame, and the busbar frame, Includes, The top frame includes a first projection at one end of the top frame that protrudes toward the upper surface of the module frame, The module frame includes a battery module that includes a second projection projecting toward the top frame at a position corresponding to the other end of the top frame located on the inner side of the upper surface, opposite to one end of the top frame.

2. The battery module according to claim 1, wherein the protrusion heights of the first protrusion and the second protrusion are the same.

3. The battery module according to claim 1 or 2, wherein each of the first and second protrusions has a shape in which the height of the protrusion decreases in the direction facing inward towards 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 busbar frame includes an extension that extends and protrudes along the 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.

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

7. The steps include forming a battery cell assembly by combining a battery cell stack in which multiple battery cells are arranged in a row and stacked adjacent to each other, a top frame that covers the upper surface of the battery cell stack, and a busbar frame that is coupled to the top frame and covers the sides of the battery cell stack, The steps include inserting the battery cell assembly into a module frame having a rectangular tubular shape, Includes, The top frame includes a first projection at one end of the top frame that protrudes toward the upper surface of the module frame, The module frame includes a second projection that protrudes inward from the module frame at a position corresponding to the other end of the top frame located on the inner side of the upper surface, opposite to one end of the top frame. A method for manufacturing a battery module, comprising the step of inserting the battery cell assembly while the top frame and the upper surface of the module frame are positioned so that they face downward in the direction of gravity, and the step of inserting the other end of the top frame toward the second protrusion.

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

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

10. Each of the first and second protrusions has a shape that is inclined such that the height of the protrusion decreases in the direction facing the inside of the module frame. The method for manufacturing a battery module according to claim 7, wherein, in the step of 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 as described in claim 1.

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