Battery module and method for manufacturing the same

Abstract

To provide a battery module having a connection structure between a busbar and an electrode lead that improves the processability and reliability of an electrical connection between the electrode lead and the busbar, and a manufacturing method for the same.SOLUTION: The present invention relates to a battery module including a busbar structure for adhesion to an electrode lead. The battery module includes a battery cell stack having a plurality of stacked battery cells, electrode leads formed to protrude from the battery cell stack, a busbar electrically connected to the electrode leads, and a busbar frame on which the busbar is mounted. The busbar is formed of a tongs part and a fixing part for connecting and fixing the tongs part. The electrode leads are attached to between the tongs part of the busbar. Such a battery module is manufactured through the steps of: attaching a busbar in an opening part of a busbar frame; inserting an electrode lead to between the tongs part of the busbar; closely adhering the busbar and the electrode lead to each other through a jig, and removing the jig.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] [Cross - reference to Related Applications] This application claims the benefit of priority based on Korean Patent Application No. 10 - 2019 - 0030176, filed on March 15, 2019, and all the contents disclosed in the document of the Korean 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 having a connection structure between an electrode lead and a bus bar and a method for manufacturing the same.

Background Art

[0003] Secondary batteries have attracted much attention as an energy source in various product groups such as mobile devices and electric vehicles. Such secondary batteries are a powerful energy resource that replaces the use of existing products using fossil fuels, and are in the spotlight as an environmentally friendly energy source because they do not generate by - products due to energy use.

[0004] Recently, as the need for large - capacity secondary battery structures, including the use of secondary batteries as an energy storage source, has increased, the demand for battery packs with a multi - module structure that aggregates battery modules in which a large number of secondary batteries are connected in series / parallel has been increasing.

[0005] On the other hand, when configuring a battery pack by connecting a plurality of battery cells in series / parallel, it is common to configure a battery module composed of at least one battery cell and add other components using such at least one battery module to configure a battery pack.

[0006] Such a battery module includes a plurality of battery cells stacked on each other and a bus bar for electrically connecting electrode leads of the plurality of battery cells.

[0007] FIG. 1 is a view showing a state in which an electrode lead in a conventional battery module is connected to a bus bar.

[0008] Referring to FIG. 1, conventionally, after stacking battery cells to form a battery cell stack 40, the battery cell stack 40 and a bus bar frame (not shown) to which a bus bar 20 is attached are assembled, and an electrode lead 10 formed to protrude from the battery cell stack is laser welded or the like to the bus bar 20 attached to the bus bar frame to join the electrode lead 10 and the bus bar 20.

[0009] However, as shown in FIG. 1, when assembling the battery cell stack 40 with the bus bar 20, the electrode lead 10 connected to the battery cell stack 40 should be bent and joined to the bus bar. However, there is a problem that a spring-back phenomenon occurs in which the bending of the already bent electrode lead is restored to its original state by elasticity in such a bending process.

[0010] Also, as similarly shown in FIG. 1, when a plurality of electrode leads 10 are bent and arranged side by side and joined to the bus bar 20, the plurality of electrode leads 10 are bent while overlapping and joined to the bus bar. At this time, an interaction of the spring-back phenomenon occurring between the electrode leads 10 and a gap between the electrode leads due to a positional difference between the electrode leads 10 caused by bending occur, and a difference also occurs in the welding joint according to the distance between the electrode lead 10 and the bus bar 20, so that the joining strength between the electrode lead 10 and the bus bar 20 decreases and an abnormality may occur in the electrical connectivity.

[0011] In addition, since the bending of the electrode lead 10 may be performed manually for reasons such as breakage of the lead, problems such as a decrease in the automation process rate and a decrease in the welding quality may occur. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0012] The problem to be solved by the present invention is to provide a battery module having a connection structure between a bus bar and an electrode lead that improves the workability and reliability of the electrical connection between the electrode lead and the bus bar, and a method for manufacturing the same.

[0013] The problems of the present invention are not limited to the problems mentioned above, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

Means for Solving the Problems

[0014] A battery module according to an embodiment of the present invention for realizing the above problems includes a battery cell stack in which a plurality of battery cells are stacked, an electrode lead formed to protrude from the battery cell stack, a bus bar electrically connected to the electrode lead, and a bus bar frame to which the bus bar is attached. The bus bar is formed of a clamping portion and a fixing portion that connects and fixes the clamping portions, and the electrode lead is attached between the clamping portions of the bus bar.

[0015] The bus bar frame may include a lower opening portion corresponding to the fixing portion of the bus bar and a hanging portion corresponding to an end portion of the clamping portion of the bus bar.

[0016] The lower opening portion may correspond to a structure in which the bus bar frame is recessed.

[0017] The clamping portion of the bus bar is formed of two clip portions extending from the fixing portion, and the distance between the two clip portions may decrease toward the fixing portion.

[0018] The electrode lead may contact the clip portion at a portion closer to the fixing portion than the end portion of the clip portion.

[0019] The electrode lead may be formed to protrude in a flat plate shape.

[0020] The battery cell laminate further includes cell terraces protruding from adjacent battery cells among the battery cells included in the battery cell laminate, and the electrode lead can be formed to protrude from the cell terrace.

[0021] The clamping portion of the bus bar can be in close contact with the flat surface of the electrode lead in a direction perpendicular thereto.

[0022] A method for manufacturing a battery module according to an embodiment of the present invention includes steps of attaching a bus bar to an opening of a bus bar frame, inserting an electrode lead between clamping portions of the bus bar, bringing the bus bar and the electrode lead into close contact with each other by a jig, and removing the jig.

[0023] In the step of bringing the bus bar and the electrode lead into close contact with each other, the jig can be inserted between the bus bar frame and the bus bar to bring the bus bar and the electrode lead into close contact with each other.

Advantages of the Invention

[0024] A battery module according to an embodiment of the present invention inserts and attaches a flat electrode lead to a bus bar, and can join the electrode lead and the bus bar without bending the electrode lead, so that reliability can be obtained in relation to the joining strength between the electrode lead and the bus bar and the resulting electrical connection.

[0025] Further, a battery module according to an embodiment of the present invention does not require a manual operation process that was necessary for bending work, so that the automation process rate in production can be improved.

[0026] Further, a battery module according to an embodiment of the present invention brings the bus bar and the electrode lead into close contact with each other by a jig so that the electrical connection between the electrode lead and the bus bar is stably performed.

[0027] Further, a battery module according to an embodiment of the present invention can reduce the weight of the bus bar due to a thin clip-shaped bus bar structure.

[0028] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description of the claims.

Brief Description of the Drawings

[0029]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0030] The embodiments described below are shown exemplarily for deepening the understanding of the invention, and it must be understood that the present invention can be variously modified and implemented differently from the embodiments described here. However, when it is determined that the specific description of related known functions or components obscures the gist of the present invention unnecessarily, the detailed description and specific illustrations thereof are omitted. Also, the attached drawings are not shown at the actual scale for deepening the understanding of the invention, and the sizes of some components may be exaggerated.

[0031] The first and second terms used in this application are used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

[0032] Also, the terms used in this application are merely for describing specific embodiments and are not intended to limit the scope of the rights. Singular expressions include plural expressions unless the context clearly indicates a different meaning. Terms such as "comprising", "consisting of", or "configured" in this application are for specifying the presence of the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and should not be understood as precluding the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0033] Hereinafter, a battery module according to an embodiment of the present invention will be described with reference to FIGS. 2 to 3.

[0034] FIG. 2 is a perspective view showing a battery module according to an embodiment of the present invention. FIG. 3 is a view showing the state where the electrode lead of FIG. 2 is inserted into the bus bar.

[0035] Referring to FIGS. 2 and 3, a battery module according to an embodiment of the present invention basically includes a battery cell stack in which a plurality of battery cells 100 are stacked, an electrode lead 120 formed to protrude from the battery cells 100 included in the battery cell stack, a bus bar 200 electrically connected to the electrode lead 120, a bus bar frame 300 to which the bus bar 200 is attached, and further includes a frame member 500 surrounding the battery cell stack and the bus bar frame 300.

[0036] The battery cell 100 can be configured as a pouch-type secondary battery as a secondary battery. The plurality of battery cells 100 can be mutually stacked so as to be electrically connected to each other to form a battery cell stack.

[0037] Such a plurality of battery cells 100 may each include an electrode assembly, a battery case, and an electrode lead 120 protruding from the electrode assembly. The electrode assembly may be composed of an anode plate, a cathode plate, a separator, and the like. The battery case is for packaging the electrode assembly and is made of a laminate sheet including a resin layer and a metal layer. Such a battery case may include a case body and a cell terrace 110. The electrode lead 120 may be electrically connected to the electrode assembly.

[0038] The configuration of the battery cell 100 described above is an example, and the form of the battery cell 100 for constituting the battery cell laminate can be variously deformed.

[0039] The electrode lead 120 is formed as a flat plate and protrudes from at least one side of the battery cell 100. Such an electrode lead 120 can protrude by being laminated in one direction, whereby series or parallel connection between the electrode leads 120 is possible. The electrode lead 120 can function as a battery terminal and is formed of a metal material such as copper or aluminum. Also, the electrode lead 120 can be formed with various thicknesses and can also be formed with various widths. The thickness and width of such an electrode lead 120 can be manufactured to be different according to the specifications of the secondary battery and the battery module.

[0040] The bus bar 200 can be in contact with the electrode lead 120 and be electrically connected. The bus bar 200 is formed of an electrically conductive metal material such as copper or aluminum, similar to the electrode lead 120, for electrical connection with the electrode lead 120.

[0041] Hereinafter, with reference to FIGS. 2 to 5, the bus bar frame, the bus bar attached thereto, and the electrode lead connected to the bus bar in a battery module according to an embodiment of the present invention will be described in detail.

[0042] FIG. 4 is a cross-sectional view of the bus bar frame of FIG. 3 as seen from the front. FIG. 5 is a cross-sectional view showing a state in which a bus bar and an electrode lead are attached to the bus bar frame of FIG. 4.

[0043] Referring to FIG. 4, the structure of the bus bar frame 300 according to the embodiment of the present invention has a part of the upper end opened to form an opening 310. The opening 310 includes a catching portion 311 having a step with reference to the entrance of the opening 310 at its upper end, and may include a lower opening portion 312 further recessed downward from the central portion of the opening 310 at its lower end.

[0044] Referring to FIG. 5, the bus bar 200 according to the present embodiment is formed of a clamping portion 210 formed to insert the electrode lead 120 and a fixing portion 220 for connecting and fixing the clamping portion 210.

[0045] The clamping portion 210 is formed of two clip portions 211 and 212 respectively extending in an upper diagonal direction from the fixing portion 220. When the electrode lead 120 is inserted, the electrode lead 120 can contact the inner surfaces of the two clip portions 211 and 212.

[0046] The fixing portion 220 can serve to connect and fix the clamping portion 210 below the clamping portion 210. The fixing portion 220 is connected to the lower ends of the two clip portions 211 and 212 respectively. According to an embodiment of the present invention, the fixing portion 220 is formed to have a curvature below the clamping portion 210, so as to facilitate the insertion of the electrode lead 120 into the clamping portion 210 and at the same time elastically prevent the deformation or movement of the clamping portion 210 so that the clamping portion 210 is fixed.

[0047] The bus bar 200 as described above is attached to an opening 310 formed in a bus bar frame 300 provided on one side of the battery cell stack. At this time, the upper end portion of the clamping portion 210 is located at the catching portion 311 of the bus bar frame 300, and the fixing portion 220 is located at the lower opening portion 312 of the bus bar frame 300.

[0048] The engaging portions 311 are respectively recessed and formed at both upper vertex portions of the opening 310, and the upper ends of the clip portions 211 and 212 on both sides of the clamping portion 210 are respectively engaged with the engaging portions 311 and attached, so that the bus bar 200 can be supported on the upper side to prevent it from moving.

[0049] The lower opening 312 is formed to correspond to the structure in which the bus bar frame 300 is recessed in the lower direction, and the fixing portion 220 is inserted and attached so that the bus bar 200 can be supported on the lower side to prevent it from moving.

[0050] As a result, the bus bar frame 300 can support the clamping portion 210 of the bus bar 200 on the upper left and right sides respectively, and support the fixing portion 220 of the bus bar at the lower center.

[0051] According to an embodiment of the present invention, the clamping portion 210 and the fixing portion 220 of the bus bar 200 are formed in a bent plate-like clip shape having a minimum width that can contact the flat plate surface of the electrode lead 120, reducing the unnecessary volume of the conventional bus bar structure and enabling a lighter bus bar device to be attached to the battery module.

[0052] The electrode lead 120 is electrically connected to the bus bar 200, and for this purpose, contact between the electrode lead 120 and the bus bar 200 is required. According to an embodiment of the present invention, the electrode leads 120 are stacked horizontally in a flat plate shape and protrude from the plurality of battery cells 100 respectively. After the protruding electrode leads 120 are inserted into the clamping portion 210 of the bus bar 200, they are contacted and fixed by the left and right clip portions 211 and 212 to form an electrical connection with the bus bar 200.

[0053] The upper side of the bus bar frame 300 has an open structure, which is formed to facilitate the insertion of the electrode lead 120 into the bus bar frame 300. The clamping portion 210 of the bus bar 200 attached inside the bus bar frame 300 is also formed with an open upper side. Therefore, the electrode lead 120 can be easily inserted and attached to the clamping portion 210 of the bus bar 200 by using the open upper structure of the bus bar frame 300 and the bus bar 200.

[0054] The distance between the two clip portions 211 and 212 becomes smaller as it goes in the direction of the lower fixing portion 220 with reference to the distance between the upper both ends of the clip portions 211 and 212. Therefore, the electrode lead 120 inserted from the upper side of the bus bar 200 can be inserted downward along the insertion space formed by the two clip portions 211 and 212 of the clamping portion 210, and the distance between the two clip portions 211 and 212 becomes smaller as it goes downward.

[0055] Therefore, the electrode lead 120 can contact the portion between the two clip portions 211 and 212 formed closer to the fixing portion 220 than the upper end side of the two clip portions. More specifically, since the flat plate surface of the electrode lead 120 corresponds to the opposing surfaces of the two clip portions 211 and 212, as a result, the clamping portion 210 of the bus bar 200 can be in close contact with the flat plate surface of the electrode lead 120 in a perpendicular direction.

[0056] According to the embodiment, the smaller the distance between the engaging portions 311 located at both upper ends of the bus bar frame 300, the smaller the distance between the two clip portions 211 and 212, and the contact position between the electrode lead 120 and the two clip portions 211 and 212 can move upward.

[0057] According to an embodiment of the present invention, in order to continuously enable the contact between the electrode lead 120 and the clamping portion 210 of the bus bar 200 in a close contact state, the contact between the two components is performed by welding.

[0058] When the electrode lead 120 is formed to protrude in a flat plate shape and is inserted and attached between clip-shaped bus bars composed of a clamping portion and a fixing portion as in the embodiment of the present invention, it is not necessary to bend the electrode lead 120, so the automation rate of the process can be improved, and since there is no risk of the springback phenomenon with respect to bending, the reliability of the electrical connection between the electrode lead and the bus bar can be ensured.

[0059] FIG. 6 is a cross-sectional view showing a state in which a jig is inserted into the bus bar frame of FIG. 5 and the bus bar and the electrode lead are in close contact with each other.

[0060] Hereinafter, a method for manufacturing a battery module according to an embodiment of the present invention will be described with reference to FIGS. 2 to 6.

[0061] First, the bus bar 200 is attached onto the opening 310 of the bus bar frame 300. The clamping portion 210 of the bus bar 200 is attached to the engaging portions 311 formed on both sides of the upper opening of the bus bar frame 300, and the fixing portion 220 of the bus bar 200 is attached to the lower opening of the bus bar frame 300. At this time, the attachment of the bus bar 200 is performed by a jig 400.

[0062] After the bus bar 200 is attached to the bus bar frame 300, the electrode lead 120 is inserted between the clamping portions 210 of the bus bar 200. As a result, the electrode lead 120 is electrically connected to the bus bar 200 on both sides.

[0063] After the electrode lead 120 is inserted between the clamping portions 210 of the bus bar 200, the bus bar 200 and the electrode lead 120 are brought into close contact with each other by a jig. As shown in FIG. 6, the jig is inserted into the space between the bus bar frame 300 and the bus bar 200, and the bus bar 200 and the electrode lead 120 can be brought into close contact with each other. By bringing the bus bar 200 and the electrode lead 120 into close contact with each other, the reliability of the electrical connection between them can be ensured.

[0064] After the bus bar 200 and the electrode lead 120 are brought into close contact with each other by the jig 400, the jig 400 can be removed from the battery module.

[0065] As described above, the preferred embodiments of the present invention have been illustrated and described. However, the present invention is not limited to the specific embodiments described above, and it goes without saying that those having ordinary knowledge in the technical field to which the present invention pertains can variously modify and implement it without departing from the gist of the present invention claimed in the claims. Such modified implementations should not be individually understood from the technical idea and prospect of the present invention.

Explanation of Reference Numerals

[0066] 100 Battery cell 110 Cell terrace 120 Electrode lead 200 Bus bar 210 Clamping portion 211 First clip portion 212 Second clip portion 220 Fixing portion 300 Bus bar frame 310 Opening 311 Hooking portion 312 Lower open portion 400 Jig

Claims

1. A battery cell stack in which a plurality of battery cells are stacked, An electrode lead formed to protrude from the battery cell stack, A bus bar electrically connected to the electrode lead, and A bus bar frame to which the bus bar is attached, The bus bar includes a clamping portion and a fixing portion that connects and fixes the clamping portions, The electrode lead is located between the clamping portions of the bus bar, The bus bar frame includes an opening, a catching portion formed above the opening so that the upper end of the clamping portion is located, and a lower opening portion formed below the opening so that the fixing portion is located, The lower opening portion is recessed and formed below the opening, and the fixing portion is inserted and attached to the lower opening portion, a battery module.

2. The catching portion is formed with a step on the upper side of the opening, and the upper end of the clamping portion is attached by catching on the step of the catching portion, the battery module according to claim 1.

3. The clamping portion of the bus bar is formed of two clip portions extending from the fixing portion, and the distance between the two clip portions becomes smaller as it goes in the direction of the fixing portion, the battery module according to claim 1 or 2.

4. The catching portions are respectively formed on both sides centered on the opening, and the upper end portions of the two clip portions are respectively attached by catching on the catching portions formed on both sides, the battery module according to claim 3.

5. The electrode lead contacts the clip portion at a portion closer to the fixing portion than the end of the clip portion, the battery module according to claim 3 or 4.

6. The electrode lead is formed to protrude in a flat plate shape, the battery module according to any one of claims 1 to 5.

7. Further includes cell terraces protruding respectively from adjacent battery cells among the battery cells included in the battery cell stack, and the electrode lead is formed to protrude from the cell terraces, the battery module according to claim 6.

8. The clamping portion of the bus bar is in close contact with the flat plate surface of the electrode lead in a perpendicular direction, the battery module according to claim 6 or 7.

9. The step of attaching the bus bar to the opening of the bus bar frame, The step of inserting the electrode lead between the clamping portions of the bus bar, The step of bringing the bus bar and the electrode lead into close contact with each other by a jig, and The method for manufacturing a battery module according to any one of claims 1 to 8, including the step of removing the jig.

10. The jig for bringing the bus bar into close contact with the electrode lead is The method for manufacturing a battery module according to claim 9, which is inserted between the bus bar frame and the bus bar to bring the bus bar into close contact with the electrode lead.

Images