COLLECTOR PLATE AND WIRE BOND INTERCONNECTS FOR BATTERY MODULE - Patent application

Abstract

The battery module comprises electrochemical cells arranged in a row, the electrochemical cells including coplanar terminals, the electrochemical cells including first and second terminals of opposite polarity at each first end of the electrochemical cells; a bus bar and a plurality of bond wires, each of the bond wires coupling the first terminal of each of the electrochemical cells to the bus bar; and a collector plate including tabs, each of the tabs coupled to a second terminal of each of the electrochemical cells.

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims priority to U.S. patent application Ser. No. 17 / 650,755, filed Feb. 11, 2022, entitled “COLLECTOR-PLATE AND WIRE-BOND INTERCONNECTIONS FOR BATTERY MODULE,” the disclosure of which is incorporated by reference in its entirety herein.

[0002] This document relates to collector plates and wire bond interconnects for battery modules. [Background technology]

[0003] In recent years, global transportation has begun to transition away from primarily fossil fuel-powered powertrains toward more sustainable energy sources, most notably electric motors powered by on-board energy storage devices. Vehicle manufacturers are striving to improve the efficiency and utility of these vehicles, including the performance of energy storage devices such as battery packs. Summary of the Invention

[0004] In a first aspect, a battery module includes electrochemical cells arranged in a row, the electrochemical cells including coplanar terminals, the electrochemical cells including first and second terminals of opposite polarity at each first end of the electrochemical cells; a bus bar and a plurality of bond wires, each of the bond wires coupling the first terminal of each of the electrochemical cells to the bus bar; and a collector plate including tabs, each of the tabs coupled to the second terminal of each of the electrochemical cells.

[0005] The implementation may include any or all of the following features: The busbar forms a first coplanar finger and the collector plate forms a second coplanar finger, the first and second coplanar fingers being coplanar with one another. The first and second coplanar fingers are interleaved with one another. The first terminal is a center terminal of the electrochemical cell. The second terminal is a rim terminal of the electrochemical cell. The first terminal is a positive terminal of the electrochemical cell. The second terminal is a negative terminal of the electrochemical cell. At least one of the tabs is coupled to a second terminal of more than one of the electrochemical cells.

[0006] In a second aspect, a method includes arranging in a row electrochemical cells including coplanar terminals, the electrochemical cells including first and second terminals at respective first ends of the electrochemical cells; coupling respective bond wires of a plurality of bond wires to the first terminals of each electrochemical cell of the electrochemical cells and to a bus bar; and coupling respective tabs of a collector plate to the second terminals of each electrochemical cell of the electrochemical cells.

[0007] The implementation may include any or all of the following features: The busbar forms a first coplanar finger and the collector plate forms a second coplanar finger. The first and second coplanar fingers are interleaved with one another. The first terminal is a center terminal of the electrochemical cell. The second terminal is a rim terminal of the electrochemical cell. The first terminal is a positive terminal of the electrochemical cell. The second terminal is a negative terminal of the electrochemical cell. Coupling the bond wire to the first terminal involves a wire bonding process. Coupling the tab to the second terminal involves a laser welding process. Coupling the tab to the second terminal involves an ultrasonic welding process. [Brief description of the drawings]

[0008] [Figure 1]FIG. 2 illustrates an example of a battery module.

[0009] [Diagram 2] FIG. 1 illustrates an example of a wire bonder head that may be used to form wire bonds.

[0010] [Diagram 3] FIG. 1 illustrates an example of a system that may be used to attach tabs of a collection plate to terminals of an electrochemical cell.

[0011] [Figure 4] FIG. 13 shows an example of bond wires coupled to the terminals of a cell and a tab of a collector plate coupled to the terminals of a cell.

[0012] [Diagram 5] FIG. 1 illustrates an example of a method.

[0013] Like reference numbers in the various drawings indicate like elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] This document describes example systems and techniques for collector plates and wire bond interconnects for battery modules. In some implementations, a hybrid solution may be used in which a terminal of one polarity is coupled to a bus bar by a bond wire, and a terminal of the opposite polarity located at the same end of the cell as the other terminal is coupled to the collector plate by a respective tab of the collector plate. For example, the hybrid approach may facilitate reduced resistance and / or improved thermal conductivity during charging or discharging of the cells, while still providing a meltable interconnect (e.g., ribbon or other bond wire) configured to melt upon the occurrence of an overcurrent, thereby interrupting the flow of electricity.

[0015] In the examples herein, reference is made to forming a bond between two or more conductive materials. As used herein, a bond may be formed by any technique that connects materials such that an electrical current can flow between them. To name just two examples, ultrasonic wire bonding and / or laser wire bonding may be used. The existence of a bond between materials indicates that the materials are electrically bonded to each other, and is referred to herein as being bonded.

[0016] Examples herein refer to electrochemical cells. As used herein, an electrochemical cell is a device that generates electrical energy from a chemical reaction, or uses electrical energy to cause a chemical reaction, or both. An electrochemical cell may include an electrolyte and two electrodes to store energy and deliver it when in use. In some implementations, an electrochemical cell may be a rechargeable cell. For example, an electrochemical cell may be a lithium-ion cell. In some implementations, an electrochemical cell may function as a galvanic cell when discharged and as an electrolytic cell when charged. An electrochemical cell may have at least one terminal for each electrode. The terminal, or at least a portion thereof, may be positioned at one end of the electrolytic cell. For example, when an electrochemical cell has a cylindrical shape, one of the terminals may be provided in the center of an end of the cell, and the can that forms the cylinder may constitute the other terminal and thus may also be present at that end. Other shapes of electrochemical cells may be used, including but not limited to prismatic shapes.

[0017] Examples herein refer to battery modules, which are individual components configured to hold and manage multiple electrochemical cells during charging, storage, and use. A battery module may be intended to be the sole power source for one or more loads (e.g., electric motors), or more than one battery module of the same or different type may be used. Two or more battery modules may be implemented in a system separately or as part of a larger energy storage unit. For example, a battery pack may include two or more battery modules of the same or different types. The battery module may include control circuitry for managing the charging, storage, and / or use of electrical energy in the electrochemical cells, or the battery module may be controlled by an external component. For example, a battery management system may be implemented on one or more circuit boards (e.g., printed circuit boards).

[0018] Examples herein refer to busbars, and a battery module may have at least one busbar. The busbar is electrically conductive and is used to conduct electricity to the electrochemical cells during charging or from the cells during discharging. The busbar is made of an electrically conductive material (e.g., metal) and has appropriate dimensions taking into account the properties and intended use of the electrochemical cells. In some implementations, the busbar comprises aluminum (e.g., an aluminum alloy). The busbar may be planar (e.g., flat) or may have one or more curves, depending on the shape and intended use of the battery module. The busbar may be configured to position the electrochemical cells in a series arrangement, a parallel arrangement, or a series and parallel arrangement.

[0019] Examples herein refer to bond wires (e.g., ribbon bond wires, or ribbon wires, or other electrical conductors). As used herein, a bond wire may have any number of different geometric shapes and may include one or more materials having respective electrical conductivities. For example, a bond wire may be a single layer bond wire, or may be a multi-layer bond wire having multiple layers, each having a respective electrical conductivity. In some implementations, a bond wire may be a ribbon wire having a rectangular cross section and one or more layers. The one or more layers may include one or more electrically conductive materials, such as one or more metals and / or metal alloys. A bond wire may include, but is not limited to, copper, aluminum, copper alloys, aluminum alloys, and / or combinations thereof. As used herein, a bond wire being coupled to a surface (e.g., a conductive surface, an electrical contact surface, etc.) refers to the bond wire being electrically and / or physically coupled to the surface, unless otherwise indicated.

[0020] Examples herein refer to top or bottom. These and similar expressions identify things or aspects relative to one another based on an explicit or arbitrary notion of perspective. That is, these terms are merely examples used for illustrative purposes and do not necessarily indicate the only possible positions, orientations, or the like.

[0021] FIG. 1 illustrates an example of a battery module 100. The battery module 100 may be used with one or more other examples described elsewhere herein. The battery module 100 includes electrochemical cells 102. The electrochemical cells 102 may have any of a number of form factors and are shown here as an example in a cylindrical shape. For example, the cylindrical shape forms an essentially circular profile at the ends seen in the figures. The electrochemical cells 102 may have terminals at the ends. Here, each of the electrochemical cells 102 has a center terminal 104A and a rim terminal 104B, both of which are at the ends shown in the figures. That is, the center terminal 104A may be located in the middle of the circular profile and the rim terminal 104B may be located at the edge of the circular profile. In some implementations, the center terminal 104A and the rim terminal 104B are of opposite polarity to each other. For example, the center terminal 104A may be a positive terminal and the rim terminal 104B may be a negative terminal.

[0022] The electrochemical cells 102 may be arranged in a row. For example, the row of cells may extend vertically or horizontally in the plane of the figure. The electrochemical cells 102 may have central terminals 104A and / or rim terminals 104B in a coplanar arrangement. For example, the central terminals 104A may all be essentially coplanar with one another in the plane of the figure. As another example, the rim terminals 104B may all be essentially coplanar with one another in the plane of the figure.

[0023] The battery module 100 may include one or more bus bars for conducting electricity to and from the electrochemical cells 102. In the present example shown in the figure, bus bar 106A may be characterized as an upper bus bar, bus bar 106B may be characterized as a middle bus bar, and bus bar 106C may be characterized as a lower bus bar. In some implementations, two or more of the bus bars 106A-106C may be coupled to one another. For example, all of the bus bars 106A-106C may be part of a common bus bar in the battery module 100. In some implementations, one or more of the bus bars 106A-106C may form coplanar fingers. For example, all of the bus bars 106A-106C may form coplanar fingers that extend from left to right in the plane of the image in the present figure. In some implementations, one or more of the bus bars 106A-106C may be interleaved with other conductive structures within the battery module 100.

[0024] The battery module 100 may include one or more collector plates for conducting electricity to or from the electrochemical cells 102. In the present example shown in the figure, the collector plate 108A may be characterized as an upper collector plate and the collector plate 108B may be characterized as a lower collector plate. In some implementations, the collector plates 108A-108B may be coupled to one another. In some implementations, one or more of the collector plates 108A-108B may form coplanar fingers. For example, each of the collector plates 108A-108B may form a respective coplanar finger that in this figure extends from right to left in the plane of the image. In some implementations, one or more of the collector plates 108A-108B may be interleaved with another conductive structure within the battery module 100.

[0025] One or more coplanar fingers of a busbar may be interleaved with one or more coplanar fingers of a collector plate. For example, the coplanar fingers of collector plate 108A are interleaved with the coplanar fingers of busbars 106A-106B. As another example, the coplanar fingers of collector plate 108B are interleaved with the coplanar fingers of busbars 106B-106C. As another example, the coplanar fingers of busbar 106B are interleaved with the coplanar fingers of collector plates 108A-108B. Other approaches may be pursued.

[0026] The collector plate may include an essentially planar structure of conductive material. In some implementations, the collector plate has essentially the same thickness throughout the collector plate. For example, the collector plate may be cut, stamped, or otherwise machined from a sheet of metal stock. The collector plate may include one or more tabs for conducting electricity to or from the electrochemical cell 102. In some implementations, the tabs may extend on one or both sides of the coplanar fingers. Here, the tab 110A of the collector plate 108A extends perpendicular to the coplanar fingers in a coplanar plane in a direction toward the busbar 106A. The tab 110A may be coupled to one or more terminals. Here, the tab 110A is coupled to a rim terminal of the cell 102A and a rim terminal of the cell 102B.

[0027] Here, the tab 110B of the collector plate 108B extends in a coplanar plane perpendicular to the coplanar fingers in a direction toward the busbar 106C. Other tabs may also or alternatively be used. The tab 110B may be coupled to one or more terminals. Here, the tab 110B is coupled to a rim terminal of the cell 102C and a rim terminal of the cell 102D.

[0028] The battery module 100 may include bond wires for conducting electricity to and from the electrochemical cells 102. The bond wires are coupled to terminals of one or more of the electrochemical cells 102. For example, the bond wires may be coupled to rim terminals or center terminals of a cell having a cylindrical form factor. Here, bond wire 112A is coupled to bus bar 106A and center terminal of cell 102A. Similarly, bond wire 112B is coupled to bus bar 106C and center terminal of cell 102C. Other approaches may be used.

[0029] 2 illustrates an example of a wire bonder head 200 that may be used to form wire bonds. The wire bonder head 200 may operate using a supply of bond wire 202. The wire bonder head 200 and / or the bond wire 202 may be used with one or more other examples described elsewhere herein. The wire bonder head 200 includes a wire guide 204. The wire guide 204 is used to guide (e.g., feed) the bond wire 202 during a bonding operation. The wire guide 204 may be made of one or more materials, including, but not limited to, metal or synthetic materials. A supply 206 of bond wire 202 is seen passing through the wire guide 204. In some implementations, the supply 206 of bond wire 202 may be provided from a spool 208. For example, the spool 208 may be rotatably suspended relative to the wire bonder head 200 to enable obtaining a supply 206 of bond wire 202 in a continuous or intermittent manner and such that the bond wire 202 has a specific orientation relative to the electrochemical cell for bonding.

[0030] The wire bonder head 200 includes a wedge 210. The wedge 210 may be used to bond the bond wire 202 to an electrochemical cell or a bus bar (not shown). For example, the wedge 210 may be made of a metal.

[0031] The wire bonder head 200 includes a cutter 212. The cutter 212 can be used to cut the bond wires 202 before, during, or after bonding. For example, the cutter 212 can be made of a metal.

[0032] FIG. 3 illustrates an example of a system 300 that may be used in attaching a tab of a collection plate to a terminal of an electrochemical cell. The system 300 or components thereof may be used with one or more other examples described elsewhere herein. The system 300 includes a bonder head 302 that is applied to the tab 304 for bonding to a substrate 306. In some implementations, the tab 304 may be attached to the substrate 306 by a laser welding process. For example, a laser 308 may generate a laser beam 310 that applies heat for melting to form at least one welded connection between the tab 304 and the substrate 306. The power of the laser 308 is controlled to form a reliable welded connection without excessive heat transfer to the substrate 306. The bonder head 302 may apply a clamping pressure.

[0033] In some implementations, the tab 304 may be attached to the substrate 306 by an ultrasonic welding process. For example, the bonder head 302 may be subjected to ultrasonic vibrations, as indicated generally by arrow 312, which generate heat for melting to form at least one welded connection between the tab 304 and the substrate 306. The power of the ultrasonic vibrations is controlled to form a reliable welded connection without excessive heat transfer to the substrate 306.

[0034] The substrate 306 may be a terminal of an electrochemical cell. In some implementations, the tab 304 may be coupled to a positive or negative cell terminal. For example, the terminal may be a rim terminal or a center terminal of a cell having a cylindrical shape.

[0035] 4 shows examples of a bond wire 400 coupled to a cell terminal 402 and a collector plate tab 404 coupled to a cell terminal 406. One or more of these examples may be used with one or more other examples described elsewhere herein. For example, the terminal 402 may be a rim terminal or a center terminal of a cell having a cylindrical shape. As another example, the terminal 406 may be a rim terminal or a center terminal of a cell having a cylindrical shape. The terminals 402 and 406 in the above examples may be part of the same cell or different cells.

[0036] 5 illustrates one example of a method 500. Method 500 may be used with one or more other examples described elsewhere herein. More or fewer operations may be performed than shown. Unless otherwise indicated, two or more operations may be performed in a different order.

[0037] At operation 502, method 500 may include arranging electrochemical cells including coplanar terminals in a row. For example, cells 102 (FIG. 1) having a cylindrical form factor may be arranged substantially as shown. The electrochemical cells include first and second terminals (e.g., center and rim terminals, respectively) at each first end of the electrochemical cells.

[0038] At operation 504, method 500 may include coupling a respective bond wire of the plurality of bond wires to a first terminal of each electrochemical cell of the electrochemical cells and to a bus bar. For example, in FIG. 1 , bond wire 112A may be coupled to bus bar 106A and a central terminal of cell 102A, and bond wire 112B may be coupled to bus bar 106C and a central terminal of cell 102C.

[0039] In operation 506, method 500 may include coupling a respective tab of the collector plate to a second terminal of each one of the electrochemical cells. For example, in FIG. 1, tab 110A may be coupled to the rim terminal of cell 102A and the rim terminal of cell 102B, and tab 110B of collector plate 108B may be coupled to the rim terminal of cell 102C and the rim terminal of cell 102D.

[0040] The terms "substantially" and "about" used throughout this specification are used to describe and report small variations, such as those due to processing variations. For example, they can refer to less than or equal to ±5%, such as less than or equal to ±2%, such as less than or equal to ±1%, such as less than or equal to ±0.5%, such as less than or equal to ±0.2%, such as less than or equal to ±0.1%, such as less than or equal to ±0.05%. Also, as used herein, indefinite articles such as "a" or "an" mean "at least one".

[0041] It should be understood that all combinations of the above concepts, and additional concepts discussed in more detail below, (provided that such concepts are not mutually inconsistent) are contemplated as part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as part of the inventive subject matter disclosed herein.

[0042] Although several implementations have been described, it will be understood that various modifications may be made without departing from the spirit and scope of the specification.

[0043] Additionally, the logic flows depicted in the figures do not require the particular order shown, or sequential order, to achieve desirable results. Additionally, other processes may be provided or processes may be eliminated from the described flows, and other components may be added to or removed from the described systems. Accordingly, other implementations are within the scope of the following claims.

[0044] While certain features of the described implementations have been illustrated as described herein, many modifications, substitutions, changes, and equivalents will now occur to those skilled in the art. It is therefore to be understood that the appended claims are intended to cover all such modifications and changes that fall within the scope of these implementations. It is to be understood that they have been presented by way of example only, and not by way of limitation, and that various changes in form and details may be made. Any part of the apparatus and / or methods described herein may be combined in any combination, except in mutually exclusive combinations. The implementations described herein may include various combinations and / or subcombinations of the functions, components, and / or features of the various implementations described. (Other possible items) (Item 1) electrochemical cells arranged in a row, the electrochemical cells including terminals in a coplanar arrangement, the electrochemical cells including first and second terminals of opposite polarity at each first end of the electrochemical cells; a bus bar and a plurality of bond wires, each of the plurality of bond wires coupling the first terminal of each electrochemical cell of the electrochemical cells to the bus bar; and a collector plate including tabs, each of the tabs being coupled to the second terminal of a respective one of the electrochemical cells; A battery module comprising: (Item 2) 2. The battery module of claim 1, wherein the busbars form first coplanar fingers and the collector plates form second coplanar fingers, the first coplanar fingers and the second coplanar fingers being coplanar with each other. (Item 3) 3. The battery module of claim 2, wherein the first coplanar fingers and the second coplanar fingers are interleaved with one another. (Item 4) 4. The battery module of any one of items 1 to 3, wherein the first terminal is a central terminal of the electrochemical cell. (Item 5) 4. The battery module of any one of items 1 to 3, wherein the second terminal is a rim terminal of the electrochemical cell. (Item 6) 6. The battery module of any one of items 1 to 5, wherein the first terminal is a positive terminal of the electrochemical cell. (Item 7) 7. The battery module of any one of items 1 to 6, wherein the second terminal is a negative terminal of the electrochemical cell. (Item 8) 8. The battery module of any one of items 1 to 7, wherein at least one of the tabs is coupled to the second terminal of more than one of the electrochemical cells. (Item 9) arranging in a row electrochemical cells including coplanar terminals, the electrochemical cells including a first terminal and a second terminal at each first end of the electrochemical cells; coupling a respective bond wire of the plurality of bond wires to the first terminal and a bus bar of each electrochemical cell of the electrochemical cells; and coupling respective tabs of a collector plate to the second terminals of each of the electrochemical cells. A method comprising: (Item 10) 10. The method of claim 9, wherein the busbar forms a first coplanar finger and the collector plate forms a second coplanar finger. (Item 11) Item 11. The method of item 10, wherein the first coplanar fingers and the second coplanar fingers are interleaved with one another. (Item 12) 12. The method of any one of items 9 to 11, wherein the first terminal is a central terminal of the electrochemical cell. (Item 13) 12. The method of any one of items 9 to 11, wherein the second terminal is a rim terminal of the electrochemical cell. (Item 14) 14. The method of any one of claims 9 to 13, wherein the first terminal is a positive terminal of the electrochemical cell. (Item 15) Item 14. The method of any one of items 9 to 13, wherein the second terminal is a negative terminal of the electrochemical cell. (Item 16) Item 16. The method according to any one of items 9 to 15, wherein the step of coupling the bond wire to the first terminal involves a wire bonding process. (Item 17) Item 16. The method of any one of items 9 to 15, wherein the step of coupling the tab to the second terminal involves a laser welding process. (Item 18) Item 16. The method of any one of items 9 to 15, wherein the step of coupling the tab to the second terminal involves an ultrasonic welding process.

Claims

1. a row of electrochemical cells including terminals in a coplanar arrangement, the electrochemical cells including first and second terminals of opposite polarity at each first end of the electrochemical cells; a bus bar and a plurality of bond wires, each of the plurality of bond wires coupling the first terminal of a respective one of the electrochemical cells to the bus bar; and a collector plate including tabs, each of the tabs being coupled to the second terminal of a respective one of the electrochemical cells; A battery module comprising:

2. 2. The battery module of claim 1, wherein the busbars form first coplanar fingers and the collector plates form second coplanar fingers, the first and second coplanar fingers being coplanar with each other.

3. The battery module of claim 2 , wherein the first coplanar fingers and the second coplanar fingers are interleaved with one another.

4. The battery module of claim 1 , wherein the first terminal is a central terminal of the electrochemical cell.

5. The battery module of claim 1 , wherein the second terminal is a rim terminal of the electrochemical cell.

6. The battery module of claim 1 , wherein the first terminal is a positive terminal of the electrochemical cell.

7. The battery module of claim 1 , wherein the second terminal is a negative terminal of the electrochemical cell.

8. 8. The battery module of claim 1, wherein at least one of the tabs is coupled to the second terminal of more than one of the electrochemical cells.

9. arranging in a row electrochemical cells including coplanar terminals, the electrochemical cells including a first terminal and a second terminal at each first end of the electrochemical cells; coupling a respective bond wire of the plurality of bond wires to the first terminal and a bus bar of each electrochemical cell of the electrochemical cells; and coupling respective tabs of a collector plate to the second terminals of each of the electrochemical cells. A method comprising:

10. The method of claim 9 , wherein the busbars form first coplanar fingers and the collector plate forms second coplanar fingers.

11. The method of claim 10 , wherein the first coplanar fingers and the second coplanar fingers are interleaved with one another.

12. The method of claim 9 , wherein the first terminal is a central terminal of the electrochemical cell.

13. The method of claim 9 , wherein the second terminal is a rim terminal of the electrochemical cell.

14. The method of claim 9 , wherein the first terminal is a positive terminal of the electrochemical cell.

15. The method of claim 9 , wherein the second terminal is a negative terminal of the electrochemical cell.

16. 16. The method of claim 9, wherein the step of coupling the bond wire to the first terminal involves a wire bonding process.

17. 16. The method of claim 9, wherein the step of coupling the tab to the second terminal involves a laser welding process.

18. 16. The method of claim 9, wherein the step of coupling the tab to the second terminal involves an ultrasonic welding process.

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