Systems and methods for manufacturing busbars

Abstract

To provide a system and a method for manufacturing a busbar which prevent battery failure occurring during welding of the busbar to a tab of a battery cell.SOLUTION: A method for manufacturing a busbar comprises: indenting a tab configured to be coupled to a busbar for a battery to form a first tab portion and a second tab portion that are separated by an indentation; pressing the first tab portion of the tab extending from the indentation against the busbar, by bending the first tab portion about the indentation; and welding the first tab portion of the tab to the busbar.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Application No. 63 / 128,557, filed December 21, 2020, the entire disclosure of which is incorporated herein by reference. [Background technology]

[0002] The described subject matter relates to systems and methods for manufacturing busbars.

[0003] Technology Considerations Busbars for high current distribution are often used to connect low voltage devices in a battery bank. To provide electrical connections, tabs are typically used that can connect the busbar to the low voltage devices. Tabs are often placed on the busbars that extend upward from the busbar for electrical connections. However, having these upward extending tabs is undesirable for packaging, such as when the space provided within the package is limited. In addition, the tabs may also interfere with the internal foil of the battery cell when compliance occurs, resulting in tearing of the foil and therefore failure of the battery cell. Thus, there may be a need for busbar manufacturing processes and systems that are different from those currently known. Summary of the Invention

[0004] In one or more embodiments, a method is provided that includes indenting a tab that can be coupled to a busbar of a battery to form a first tab portion and a second tab portion separated by the indentation, bending the first tab portion around the indentation to press the first tab portion against the busbar, and securing the first tab portion to the busbar.

[0005] In one or more embodiments, an assembly is provided and may include a press that may form a recess in the tab, a roller assembly including a rolling element that may press a first tab portion of the tab extending from the recess against the busbar, and a welding device that may weld the first tab portion of the tab to the busbar.

[0006] In one or more embodiments, a method is provided that may include indenting a tab that may be coupled to a busbar of a battery to form a first tab portion and a second tab portion separated by a indentation, and inserting the tab into an opening in the busbar such that the first tab portion extends away from the opening. The method may also include bending the first tab portion around the indentation to a weld location adjacent the busbar, and welding the first tab portion to the busbar. [Brief description of the drawings]

[0007] The subject matter of the present invention can be understood from reading the following description of non-limiting embodiments with reference to the accompanying drawings, in which:

[0008] [Figure 1] FIG. 1 shows a block schematic diagram of a vehicle system. [Diagram 2] FIG. 2 shows a block schematic diagram of the control system. [Figure 3A] 1 shows a schematic diagram of a press. [Figure 3B] 1 shows a side view of the tab during manufacturing. [Figure 4] FIG. [Diagram 5] FIG. 1 shows a block schematic diagram of a process for manufacturing a busbar. [Figure 6A] 1 shows a side perspective view of a busbar during manufacturing. [Figure 6B] 1 shows a side perspective view of a busbar during manufacturing. [Figure 6C] 1 shows a side perspective view of a busbar after a manufacturing process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] SUMMARY OF THE EMBODIMENTS OF THE EMBODIMENTS SUMMARY OF THE EMBODIMENTS

[0003] The subject matter described herein relates to a system and method for manufacturing a busbar. A dimple is formed in a tab that provides an electrical connection to the busbar. The dimple is formed prior to laser welding the busbar to a battery or other electronic component. Specifically, the dimple is formed to facilitate bending the tab. As such, a rolling element may be implemented to press a first tab portion of the tab to the busbar prior to laser welding. Specifically, laser welding may require intimate contact of material surfaces (e.g., between the busbar and the battery cell). Thus, simply bending the tab may lead to process variations that may ultimately affect laser welding the tab to the busbar system. Specifically, when a force is placed on one end of a metal sheet while the other is fixed, bending may occur at different locations along the sheet. By placing a dimple in the tab prior to the rolling process, the dimple is in the position where bending occurs. The dimple also functions to provide less resistance or elasticity compared to a metal sheet without the dimple. As a result, the indentation reduces the elastic force of the metal sheet that would otherwise cause the tab to move back toward its original position and away from the busbar after pressing, rather than remaining flat against the busbar before welding occurs, thus improving welding. By providing flatness against the busbar, the battery cell is also protected from affecting the battery's internal foil, including tearing of the foil, through compliance, thereby preventing failure of the battery during welding.

[0010] The battery cells described herein may be utilized to power rail vehicle systems, such as locomotives. Yet, not all embodiments described herein are limited to rail vehicle systems. For example, one or more embodiments of the busbars and methods described herein may be used with other types of vehicles, such as automobiles, trucks, buses, mining vehicles, marine vehicles, aircraft, agricultural vehicles, and the like.

[0011] 1 shows a schematic diagram of a vehicle system 100 including a control system 102. The vehicle system 100 may use a battery that includes a busbar manufactured using the manufacturing processes described herein. The vehicle system may travel along a route 104 as it travels from a start or departure location to a destination or arrival location. The vehicle system includes a propulsion producing vehicle 108 and a non-propulsion producing vehicle 110 that are mechanically interconnected to each other for traveling together along the route. The vehicle system may include at least one propulsion producing vehicle and, optionally, one or more non-propulsion producing vehicles.

[0012] 2 provides a schematic block diagram of an assembly 200 for manufacturing a busbar 202 including a tab 204 having a first tab portion 206, a second tab portion 208, and a recess 210. Any component of the assembly may be utilized by an individual or, alternatively, may be controlled by a control system.

[0013] The assembly 200 includes a press 212 that can form a recess in the tab. In one embodiment, the press can be a punch press. FIG. 3A shows a partial view of the press in more detail. Specifically, the press 212 has a housing 214 that includes a stationary press component 216 and an actuating press component 218. The stationary component does not move during the pressing process, and the tab is fixed to the stationary component for the recess. Meanwhile, the actuating press component moves from a first position above the stationary press component to a second position relative to the tab on the stationary press component. The actuating press component can be moved manually, pneumatically, etc. to provide a pressing force to the tab. Coupled within the actuating press component is a first insert 220 that is positioned above a second insert 222 that is coupled within the stationary press component. The first insert includes a press recess 224 that is received by a notch 226 located within the second insert. The recess and notch mate with each other. In this manner, the tabs of the busbar are secured to the stationary press component, and when the actuating press component engages the tabs and presses against the stationary press component, a recess is formed in the tabs, as illustrated in FIG. 3B.

[0014] 2, the assembly also includes a roller assembly 228 that receives the busbar after its tabs are placed through corresponding openings in the busbar. Specifically, each tab may be positioned in a busbar opening and clamped to the busbar such that a first tab portion extends upward from the opening and a second tab portion extends downward through the opening.

[0015] The roller assembly is illustrated in further detail in FIG. 4. The roller assembly includes an end cap 232 over which the busbar moves laterally. Specifically, the busbar may be secured to the end cap to prevent movement relative to the end cap itself. A blocking element 234 is disposed on the end cap to engage a first tab portion of the busbar to bend the first tab portion around the recess. In one embodiment, the blocking element includes an arcuate surface 236 between a first end 238 and a second end 239. The arcuate surface engages the first tab portion to facilitate bending the first tab portion around the recess. In other embodiments, the blocking element includes an inclined plane, a flat surface, or the like, to force down the first tab portion.

[0016] The roller assembly also includes a rolling element 240 that can press the first tab portion against the busbar. The rolling element can be positioned adjacent to the block element such that as the busbar moves along the end cap, first, the block element bends the first tab portion downward at an angle with the end cap, and second, the rolling element presses the first tab portion against the busbar to flatten the first tab portion. The rolling element can be a wheel, end cap, etc. that presses the first tab portion against the busbar. The rolling element can be positioned at a height equal to the width of the location of the first tab away from the busbar. In this way, the first tab portion is completely flattened against the busbar after exiting the roller assembly. To press the first tab portion against the busbar, in one embodiment, a rolling element can be utilized, although a linear press, paddle, or other pressing device can be utilized.

[0017] As a result of the indentations located on the tabs, the force applied to the tab is distributed through the indentations to the second tab portion as the blocking and rolling elements bend and compress the first tab portion around the indentations. By dissipating the force, a uniform compression is provided to each individual tab at the same indentation location for multiple tabs on the busbar.

[0018] Referring again to FIG. 2, the assembly may also include a welding device 241 that may weld the first tab portion of the tab to the busbar. The welding device may be a laser welder, an ultrasonic welder, or the like. The welding device may be operated manually by an operator or automatically as an automatic welding device in an assembly line. The welding device may weld similar or dissimilar materials together. By dissipating the force at the same recess location of the multiple tabs of the busbar, a uniform weld is facilitated. Thus, poor weld conditions are similarly reduced as a result of the first tab portion extending away from the busbar. Thus, damage to the battery due to foil tearing or other packaging related defects are also reduced, improving the overall life of the battery.

[0019] The assembly may also optionally include a control system 242. The control system may include one or more processors 244, memory or storage 246, and a transceiver 248 for communicating data and information. The controller memory may include a tangible, non-transitory computer-readable storage medium that temporarily or permanently stores data for use by the one or more processors. The memory may include one or more volatile and / or non-volatile memory devices, such as random access memory (RAM), static random access memory (SRAM), dynamic RAM (DRAM), another type of RAM, read-only memory (ROM), flash memory, magnetic storage (e.g., hard disk, floppy disk, or magnetic tape), optical disk, and the like. The control system may be communicatively coupled to each of the press, roller assembly, and welding equipment to automate each during operation. "Communicatively coupled" means that two devices, systems, subsystems, assemblies, modules, components, etc. are connected by one or more wired or wireless communication links, such as one or more electrically conductive (e.g., copper) wires, cables, or buses, a wireless network, fiber optic cables, etc.

[0020] In one embodiment, the press, roller assembly, and welding equipment are all controlled by a control system. Alternatively, the control system controls only one or only two of the press, roller assembly, and welding equipment. In yet another embodiment, no control system is utilized and each of the press, roller assembly, and welding equipment is manually operated by an individual.

[0021] Figure 5 shows a block flow diagram of a process 500 for manufacturing a busbar. In one embodiment, the busbar is utilized in a battery cell of a vehicle system as described with reference to Figure 1. In another embodiment, the busbar is manufactured utilizing the assembly as described with reference to Figure 2.

[0022] At step 502, the tab is recessed to configure the tab to be coupled to the busbar and form a first tab portion and a second tab portion separated by a recess. In one embodiment, the tab is inserted into a press including a first insert having a press recess and a second insert having a press notch that matingly receives the press recess. The press may include an actuating press component and a stationary press component, where the actuating press component moves from a first position above the stationary press component to a second position where it presses against the tab positioned on the stationary press component. In one embodiment, multiple tabs may be fed into the press one at a time. Once the tab is positioned in the correct position, the actuating press component moves to press the tab to form the recess. The press may be fed and operated automatically by a control system or may be operated manually by an operator.

[0023] At step 504, a plurality of tabs are inserted into openings in corresponding bus bars. Each bus bar includes at least one opening to receive a tab. Each tab is disposed in a separate opening, with a first portion of the tab extending in a first direction, such as upward, from the opening, while a second portion of the tab extends in a second direction, such as downward, from the opening. Thus, the recesses align with the inner walls of the openings. In one embodiment, the second portions of the tabs may be secured or clamped to the bus bars to hold the tabs in place during the manufacturing process.

[0024] At step 506, as the busbar moves relative to the roller assembly, the first tab portion engages the block element to bend the first tab around the recess. In one embodiment, the busbar is on an end cap that holds the busbar in place relative to the end cap, and moves the busbar along the end cap relative to the block element. Alternatively, the busbar can be placed on a fixed surface and the block element can move relative to the fixed surface to laterally engage the first tab portion of the tab.

[0025] In one embodiment, the block element includes an arcuate surface that gradually bends the first tab portion downward around the recess. Alternatively, the block element may include an inclined surface, a flat surface, or the like. As the first tab portion engages the block element, the block element presses the first tab portion downward, such that after the block element disengages, the first tab portion is at an acute angle with respect to the busbar. In this manner, the first tab portion is bent and positioned such that the roller element presses the first tab portion against the busbar.

[0026] At step 508, the first tab portion is forced against the busbar by bending the first tab portion around the recess. In one embodiment, as the rolling element forces the first tab portion against the busbar, the rolling element engages the first tab portion to bend the first tab portion around the recess. Specifically, as the busbar moves laterally relative to the rolling element, the rolling action gradually bends the first tab portion to ensure that the force is concentrated through the recess to the second tab portion of the tab. Alternatively, other pressing devices besides the rolling element may be utilized to force and bend the first tab portion around the recess. Once the first tab portion is forced against the busbar, the tab is considered to be in a weld position.

[0027] At step 510, a first tab portion is secured to the busbar. In one embodiment, the first tab portion is welded to the busbar. More specifically, the first tab portion may be laser welded, ultrasonically welded, or the like, to the busbar. In one embodiment, there are multiple tabs on the busbar, whereby a first tab portion of a first tab, followed by a first tab portion of a second tab, and a first tab portion of a third tab are welded to the busbar. In an embodiment, there may be fewer than three first tab portions secured to the busbar, or more than three first tab portions secured to the busbar. Overall, by utilizing the methods provided, consistent and repeatable welds may be provided, reducing packaging issues associated with the tabs.

[0028] FIG. 6A illustrates a first busbar having a plurality of tabs 602A-F (a first tab 602A, a second tab 602B, a third tab 602C, a fourth tab 602D, a fifth tab 602E, and a sixth tab 602F) disposed through a plurality of openings 604A-F (a first opening 604A, a second opening 604B, a third opening 604C, a fourth opening 604D, a fifth opening 604E, and a sixth opening 604F) during a pressing process. FIG. 6B illustrates a first busbar 600A and a second busbar 600B having a plurality of tabs 606A-F (first tab 606A, second tab 606B, third tab 606C, fourth tab 606D, fifth tab 606E, and sixth tab 606F) disposed through a plurality of openings 608A-F (first opening 608A, second opening 608B, third opening 608C, fourth opening 608D, fifth opening 608E, and 608F). Meanwhile, FIG. 6B illustrates the first and second busbars after the pressing process. As illustrated, the first tab portions 610A-F and 612A-F of each tab are initially approximately perpendicular to the busbars in a first position. Then, after engaging with the block element, each first tab portion is bent at an acute angle to a second position relative to the respective busbar.

[0029] After each busbar passes through the rolling element, each first tab portion is in a final position or flat welding position relative to the respective busbar that is approximately horizontal or parallel to the busbar. As illustrated in FIG. 6B, each first tab portion is approximately uniformly straight relative to the busbar surface. This is the result of the indentation of each tab, which transfers the forces of both the block element and the rolling element to the correct position to ensure uniformity. As a result, compliance to avoid the thin inner layer of the foil of the battery cell is protected from damage, while providing a consistent colinear surface for welding the tabs. In addition, deformation between the tabs can also be eliminated.

[0030] 6C illustrates the first busbar after the welding process. The first tab portion is uniformly secured to the busbar, providing a secure bond between the busbar and the tab. As a result, the tab encompasses a reduced amount of vertical space compared to a tab that does not undergo the process described herein. Thus, the tab is less likely to catch on the foil of the battery and cause damage to the battery, reducing battery failure.

[0031] In one or more embodiments, a method is provided that includes indenting a tab that can be coupled to a busbar of a battery to form a first tab portion and a second tab portion separated by the indentation, bending the first tab portion around the indentation to press the first tab portion against the busbar, and securing the first tab portion to the busbar.

[0032] Optionally, the method may also include positioning the tab through the opening in the busbar such that the first tab portion extends upwardly away from the opening and the second tab portion extends downwardly away from the opening. In one aspect, the method may also include clamping the tab to the busbar prior to pressing the first tab portion against the busbar to secure the first tab portion to the busbar. In one example, pressing the first tab portion against the busbar may include pressing the first tab portion with a rolling element as the rolling element moves relative to the busbar. Alternatively, prior to pressing the first tab portion against the busbar with the rolling element, the method may include pressing the first tab portion downwardly to bend the first tab portion around a recess.

[0033] Optionally, securing the first tab portion to the busbar may include laser welding the first tab portion to the busbar. In one aspect, the tab may be a first tab, the opening in the busbar may be a first opening, and the busbar may include a second opening that receives a second tab having the first and second tab portions separated by a recess. The method may also include compressing the first tab portion of the second tab to the busbar by bending the first tab portion of the second tab around the recess of the second tab, and securing the first tab portion of the second tab to the busbar. In another aspect, the first tab portion of the first tab and the first tab portion of the second tab may be compressed by a rolling element moving relative to the busbar.

[0034] In one or more embodiments, an assembly is provided and may include a press that may form a recess in the tab, a roller assembly including a rolling element that may press a first tab portion of the tab extending from the recess against the busbar, and a welding device that may weld the first tab portion of the tab to the busbar.

[0035] Optionally, the roller assembly may also include a block element that may engage the first tab portion to bend the first tab portion around the recess before the first tab portion is pressed by the rolling element. In one aspect, the block element may have an arc surface that may engage the first tab portion to bend the first tab portion around the recess. In another aspect, the roller assembly may include an end cap that may receive the bus bar and move the bus bar relative to the block element and rolling element. In one example, the press may include a first insert matingly received by the second insert. In another example, the welding device may be a laser welder.

[0036] In one or more embodiments, a method is provided that may include indenting a tab that may be coupled to a busbar of a battery to form a first tab portion and a second tab portion separated by a indentation, and inserting the tab into an opening in the busbar such that the first tab portion extends away from the opening. The method may also include bending the first tab portion around the indentation to a weld location adjacent the busbar, and welding the first tab portion to the busbar.

[0037] Optionally, the method may also include clamping a second tab portion of the tab to the busbar prior to bending the first tab portion about the recess. In one aspect, bending the first tab portion about the recess to a welding position adjacent the busbar may include pressing the first tab portion downward with a block element and pressing the first tab portion with a rolling element after pressing the first tab portion downward with the block element. In another aspect, welding the first tab portion to the busbar may include laser welding the first tab portion to the busbar.

[0038] In one example, the tab may be a first tab, the opening in the busbar may be a first opening, the welding location may be a first welding location, and the busbar may include a second opening that receives a second tab having a first tab portion and a second tab portion separated by a recess. The method may also include bending the second tab portion around the recess in the second tab to a second welding location adjacent the first tab portion, and welding the first tab portion of the second tab to the busbar. Additionally, the first tab portion of the first tab and the first tab portion of the second tab may be compressed by a rolling element moving relative to the busbar.

[0039] As used herein, the terms "processor" and "computer" and related terms, such as "processing device", "computing device", and "controller", may not be limited to only integrated circuits referred to in the art as computers, but may refer to microcontrollers, microcomputers, programmable logic controllers (PLCs), field programmable gate arrays, and application-specific integrated circuits, as well as other programmable circuits. Suitable memory may include, for example, computer-readable media. The computer-readable media may be, for example, computer-readable non-volatile media such as random access memory (RAM), flash memory, and the like. The term "non-transitory computer-readable media" refers to tangible computer-based devices implemented for short-term and long-term storage of information, such as computer-readable instructions, data structures, program modules and sub-modules, or other data within any device. Thus, the methods described herein may be coded as executable instructions embodied in tangible non-transitory computer-readable media, including but not limited to storage devices and / or memory devices. Such instructions, when executed by a processor, cause the processor to perform at least a portion of the methods described herein. As such, the term includes tangible computer-readable media, including but not limited to non-transitory computer storage, including but not limited to, volatile and non-volatile media, and removable and non-removable media, such as firmware, physical and virtual storage devices, CD-ROMs, DVDs, and other digital sources such as a network or the Internet.

[0040] The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. "Optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description may include instances in which the event occurs and instances in which it does not occur. As used throughout this specification and claims, approximation language may be applied to modify quantitative expressions that may vary within acceptable limits without resulting in a change in the basic function to which they may relate. Thus, values ​​modified by one or more terms such as "about," "substantially," "approximately," etc. may not be limited to the exact value specified. In at least some cases, approximation language may correspond to the precision of an instrument for measuring the value. Here, and throughout this specification and claims, range limitations may be combined and / or interchanged, and such ranges may include all subranges identified and contained therein, unless the context or language dictates otherwise.

[0041] This written description uses examples to disclose embodiments, including the best mode, and to enable any person skilled in the art to practice embodiments of the invention, including making and using any devices or systems, and performing any incorporated methods. The claims define the patentable scope of the disclosure, and include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that differ insubstantially from the literal language of the claims.

Claims

1. 1. A method comprising: indenting a tab configured to be coupled to a bus bar of a battery to form a first tab portion and a second tab portion separated by a recess; bending the first tab portion into the recess to compress the first tab portion against the busbar while the busbar is secured to an end cap that extends below the busbar and retains the busbar; and securing the first tab portion to the bus bar.

2. 2. The method of claim 1 , further comprising positioning the tab through the opening in the bus bar such that the first tab portion extends upwardly away from the opening and the second tab portion extends downwardly away from the opening.

3. The method of claim 2 , further comprising clamping the tab to the busbar before pressing the first tab portion against the busbar to secure the first tab portion to the busbar.

4. The method of claim 1 , wherein forcing the first tab portion against the busbar comprises forcing the first tab portion with a rolling element as the rolling element moves relative to the busbar.

5. 5. The method of claim 4, wherein prior to forcing the first tab portion against the busbar with the rolling element, the method includes pressing the first tab portion downward to bend the first tab portion at the depression.

6. The method of claim 1 , wherein securing the first tab portion to the bus bar comprises laser welding the first tab portion to the bus bar.

7. the tab is a first tab, the opening in the busbar is a first opening, the busbar includes a second opening for receiving a second tab having a first tab portion and a second tab portion separated by a recess, and the method further comprises: compressing the first tab portion of the second tab against the busbar by bending the first tab portion of the second tab into the recess of the second tab; The method of claim 2 , further comprising: securing the first tab portion of the second tab to the bus bar.

8. The method of claim 7 , wherein the first tab portion of the first tab and the first tab portion of the second tab are compressed by a rolling element moving relative to the busbar.

9. 1. An assembly comprising: a press configured to form a recess in the tab; a roller assembly including a rolling element configured to press a first tab portion of the tab extending from the recess against a busbar to bend the tab at the recess, the roller assembly including an end cap extending below the busbar and retaining the busbar; a welding device configured to weld the first tab portion of the tab to the busbar.

10. 10. The assembly of claim 9, wherein the roller assembly also includes a block element configured to engage the first tab portion to bend the first tab portion at the recess before the first tab portion is pressed by the rolling element.

11. The assembly of claim 10 , wherein the blocking element has an arcuate surface that engages the first tab portion to bend the first tab portion at the recess.

12. The assembly of claim 10 , wherein the end caps are configured to receive the bus bars and move the bus bars relative to the block elements and the rolling elements.

13. The assembly of claim 9 , wherein the press includes a first insert matingly received by a second insert.

14. The assembly of claim 9 , wherein the welding device comprises a laser welder.

15. 1. A method comprising: indenting a tab configured to be coupled to a bus bar of a battery to form a first tab portion and a second tab portion separated by a recess; inserting the tab into an opening in the busbar such that the first tab portion extends away from the opening; bending the first tab portion at the recess to a welding location adjacent the busbar while the busbar is secured to an end cap that extends below the busbar and retains the busbar; and welding the first tab portion to the bus bar.

16. 16. The method of claim 15, further comprising clamping the second tab portion of the tab to the bus bar before bending the first tab portion at the depression.

17. bending the first tab portion at the recess to the welding location adjacent the bus bar; pressing the first tab portion downward with a blocking element; 16. The method of claim 15, further comprising: pressing the first tab portion downward with the blocking element followed by compressing the first tab portion with a rolling element.

18. The method of claim 15 , wherein welding the first tab portion to the busbar comprises laser welding the first tab portion to the busbar.

19. the tab is a first tab, the opening in the busbar is a first opening, the weld location is a first weld location, the busbar includes a second opening for receiving a second tab having a first tab portion and a second tab portion separated by a recess, and the method further comprises: bending the second tab portion at the recess of the second tab to a second weld location adjacent the bus bar and the first tab portion; The method of claim 15 further comprising: welding the first tab portion of the second tab to the busbar.

20. 20. The method of claim 19, wherein the first tab portion of the first tab and the first tab portion of the second tab are compressed by a rolling element moving relative to the busbar.

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