CN112602231A

CN112602231A - Bus bar with integrated stamped fusible link

Info

Publication number: CN112602231A
Application number: CN201980054437.4A
Authority: CN
Inventors: T·D·柯林斯; K·W·巴特菲尔德; N·C·温; C·E·常
Original assignee: Rivian IP Holdings LLC
Current assignee: Rivian IP Holdings LLC
Priority date: 2018-08-23
Filing date: 2019-08-23
Publication date: 2021-04-02
Anticipated expiration: 2039-08-23
Also published as: WO2020041764A1; CN112602231B; DE112019004220T5

Abstract

A battery interconnect may include a desired current capacity, an integrated fusible link, and may be manufactured using cost effective techniques. In some embodiments, the battery interconnector includes a bus bar and a relatively thin link. The bus bars carry a large current and therefore have a relatively large cross-sectional area to reduce ohmic losses. The link carries much less current and the fusible link is configured to open the circuit when the current is above a threshold, thus requiring a relatively small cross-sectional area. Several techniques are used to address these sometimes disparate length scales, such as stacking the bus bar and foil and pressing portions of the bus bar to form the coupling. The coupling member may be attached to a plurality of battery cells to connect the cells in parallel or in series.

Description

Bus bar with integrated stamped fusible link

Introduction to the design reside in

Battery systems typically include a number of battery cells connected together in a combination of series and parallel connections. In many cases, it is desirable to include a fusible link for a group of cells that is as small as possible in an automotive battery pack for safety reasons. Ideally, each cell has at least one fusible link. The fusing current depends mainly on the minimum cross-sectional area (i.e., throat). For example, for aluminum 1100 to melt in 1s at about 40A in air, a cross section of approximately 0.2 square millimeters is required. Therefore, in order to make a 1mm thick aluminum busbar with a cross section suitable for melting, the width of the throat needs to be 0.2 mm. This is not applicable to any production-scalable manufacturing technique. For example, a typical minimum ratio between feature width and sheet thickness is about 5:1 for embossing, 3:1 for water jet or laser cutting, and 1:1 for wire electrical discharge machining, but the geometry will have a ratio of 1: 5. It would be advantageous to provide an improved fusible link having a desired cross-sectional area.

Typically, the bus bars are connected to the cylindrical lithium ion battery cells using wire bonding, laser welding, and resistance welding. For example, fig. 1 shows wire bond connections of the battery cell 110 to the

current collectors

101 and 102. Battery cell 110 has a positive terminal (+) and a negative terminal (-). A lead 111 connects the negative terminal of the battery cell 110 to the current collector 101, and a lead 112 connects the positive terminal of the battery cell 110 to the current collector 102. The

wires

111 and 112 are sized to act as fusible links. This connection scheme requires two wires per unit and four bonding areas. The bus bars connect a series of cells into the desired series and parallel strings. Wire bonding includes ultrasonically welding a conductive wire to both the cell and the bus bar. The length and diameter of the wire may be sized to act as a fuse at currents higher than the normal operating conditions of the unit, providing additional safety in the event of over-current and short circuit conditions. One problem with wire bonding is that when a large number of connections are to be made in battery modules and battery packs, wire bonding can become a bottleneck in production due to the speed and success rate of bonding. For example, it may take about one second to perform a connection. Furthermore, success rates are typically in the range of 99% to 99.99%. On a battery with 5000 cells, connections to the positive and negative electrodes are required, which would result in 10000 connections for cells only and a total of 20000 connections. This indicates that even if a 99.99% success rate is achieved, there are two failures on average. Therefore, it would be advantageous to use a faster, more reliable method of connecting the battery to the bus bar while maintaining a fusible link.

Disclosure of Invention

In some embodiments, the present disclosure relates to a battery interconnector system, which includes at least one bus bar and at least one foil. The foil is attached to the at least one busbar at an interface and includes a first plurality of tabs extending from the interface. The first plurality of tabs are configured to contact corresponding terminals of the first plurality of battery cells. Each tab of the first plurality of tabs includes a fusible link.

In some embodiments, the at least one foil is attached to the at least one busbar at the interface by at least one of ultrasonic welding, laser welding, pressure welding, and explosion welding.

In some embodiments, at least one busbar includes a branch.

In some embodiments, each of the respective fusible links includes a predetermined local minimum cross-sectional area configured to melt at a substantially predetermined current.

In some embodiments, the foil layer includes a second plurality of tabs extending from the interface to the second plurality of battery cells.

In some embodiments, the first plurality of tabs extends to corresponding terminals of the first plurality of battery cells having a first polarity and the second plurality of tabs extends to corresponding terminals of the second plurality of battery cells having a second polarity. For example, the first and second polarities may be positive and negative polarities.

In some embodiments, each tab of the second plurality of tabs extends to two terminals of the second polarity of two battery cells of the second plurality of battery cells.

In some embodiments, the at least one busbar has a first thickness, the first plurality of tabs has a second thickness, and the second thickness is one quarter or less of the first thickness. In some embodiments, the second thickness is one tenth or less of the first thickness.

In some embodiments, at least one of the bus bars has an in-plane shape, at least one of the foils has substantially the same in-plane shape, and the interface is planar and has the same in-plane shape.

In some embodiments, the present disclosure relates to a battery system including a plurality of battery cells grouped into at least one group of battery cells, and an interconnect coupled to the at least one group of battery cells. The interconnector includes a busbar and a foil layer attached to the busbar at an interface. The foil layer includes a first plurality of tabs extending from the interface to terminals of at least one group of battery cells. Each tab of the first plurality of tabs includes a fusible link, and each tab of the first plurality of tabs is attached to a terminal.

In some embodiments, the present disclosure relates to a method for forming a battery interconnect system. The method includes aligning the foil blank with the bus bar. The method also includes attaching the foil blank to a bus bar to form an interconnector blank. The method also includes cutting the attached foil blank to form an interconnector having a plurality of foil tabs including at least one fusible link.

In some embodiments, the method includes attaching a carrier to the interconnect and at least one other interconnect to maintain a spatial arrangement of the interconnect and the at least one other interconnect.

In some embodiments, cutting the foil blank comprises stamping the foil blank to form a plurality of foil tabs. In some embodiments, stamping the foil blank comprises stepping the stamped foil blank to form a plurality of foil tabs.

In some embodiments, the at least one fusible link comprises a predetermined cross-sectional area configured to melt at a substantially predetermined current.

In some embodiments, the method comprises cutting the interconnector blank after stamping the attached foil blank to form at least two interconnectors. In some such embodiments, the method includes stamping the interconnector blank. Further, in some embodiments, the method includes attaching the carrier to at least two interconnectors to maintain a spatial arrangement of the at least two interconnector blanks, and the at least two attached interconnectors are electrically isolated from each other.

In some embodiments, the carrier includes a plurality of grooves configured to allow attachment of a plurality of foil tabs to a plurality of corresponding battery cells. In some embodiments, the method includes attaching a plurality of foil tabs to a plurality of corresponding battery cells.

In some embodiments, the present disclosure is directed to a battery interconnector system including at least one busbar having a first thickness and a first plurality of stamped tabs having a second thickness, the first plurality of stamped tabs extending from the busbar and configured to contact corresponding terminals of a first plurality of battery cells. A first plurality of stamped tabs is connected to the at least one busbar, wherein each stamped tab of the first plurality of stamped tabs comprises a fusible link, and wherein the second thickness is one quarter or less of the first thickness. For example, in some embodiments, the at least one bus bar and the first plurality of stamped tabs are formed from a single piece of material. In another example, in some embodiments, the first plurality of stamped tabs is formed by pressing a material having a first thickness.

In some embodiments, the battery interconnect system includes a second plurality of stamped tabs extending from the bus bar to a second plurality of battery cells.

In some embodiments, the first plurality of tabs extends to corresponding terminals of the first plurality of battery cells having a first polarity and the second plurality of stamped tabs extends to corresponding terminals of the second plurality of battery cells having a second polarity.

In some embodiments, each stamped tab of the second plurality of stamped tabs extends to two terminals of the second polarity of two battery cells of the second plurality of battery cells.

In some embodiments, the second thickness is one tenth or less of the first thickness.

In some embodiments, the first plurality of stamped tabs is formed by pressing a material having a first thickness.

In some embodiments, the at least one bus bar comprises one or more branches, and the first plurality of stamped tabs extends from the one or more branches.

In some embodiments, the present disclosure relates to a battery system including a plurality of battery cells grouped into at least one group of battery cells, and an interconnect coupled to the at least one group of battery cells. The interconnector includes at least one busbar having a first thickness and a first plurality of stamped tabs having a second thickness, the first plurality of stamped tabs extending from the busbar and configured to contact corresponding terminals of a first plurality of battery cells. The first plurality of stamped tabs is connected to at least one bus bar. Each stamped tab of the first plurality of stamped tabs includes a fusible link. The second thickness is one-fourth or less of the first thickness.

In some embodiments, the present disclosure relates to a method for forming a battery interconnect system. The method includes forming an interconnector blank having a first thickness. The method also includes pressing a portion of the interconnector blank to form a plurality of green tabs having a second thickness. The second thickness is one-fourth or less of the first thickness. The method also includes cutting the plurality of rough tabs to form an interconnector having a plurality of tabs including at least one fusible link.

In some embodiments, pressing the portion of the interconnector blank comprises progressive pressing and trimming the portion to form a plurality of green tabs.

In some embodiments, cutting the plurality of rough tabs comprises stamping the interconnector blank to form the plurality of tabs.

In some embodiments, the method includes cutting the interconnector blank after cutting the plurality of rough tabs to form at least two interconnectors. In some such embodiments, cutting the interconnector blank comprises stamping the interconnector blank. Further, in some such embodiments, the method includes attaching the carrier to the at least two interconnectors to maintain a spatial arrangement of the at least two interconnector blanks, and the at least two attached interconnectors are electrically isolated from each other.

In some embodiments, the method includes attaching a plurality of tabs to a plurality of corresponding battery cells through a groove in a carrier.

In some embodiments, forming the interconnector blank comprises forming a busbar having a plurality of projections, and the portion of the interconnector blank comprises the plurality of projections. For example, the projections are stamped to form a plurality of tabs.

Drawings

The present disclosure in accordance with one or more various embodiments is described in detail with reference to the following drawings. The drawings are provided for purposes of illustration only and merely depict typical or example embodiments. These drawings are provided to facilitate an understanding of the concepts disclosed herein and should not be taken to be a limitation on the breadth, scope, or applicability of these concepts. It should be noted that for clarity and ease of illustration, the drawings are not necessarily drawn to scale.

Fig. 1 shows a wire bond connection of a battery cell to a current collector;

fig. 2 shows a top view of an illustrative battery module having a plurality of battery interconnects disposed between a plurality of battery cells, in accordance with some embodiments of the present disclosure;

fig. 3 shows an enlarged view of a portion of the illustrative battery module of fig. 2, in accordance with some embodiments of the present disclosure;

fig. 4 shows a top view of a portion of an illustrative interconnector blank, according to some embodiments of the present disclosure;

fig. 5 shows a top view of a portion of the exemplary interconnector blank of fig. 4 after pressing, according to some embodiments of the present disclosure;

fig. 6 shows a top view of a portion of the exemplary interconnector blank of fig. 5 after trimming, according to some embodiments of the present disclosure;

fig. 7 shows a top view of a portion of the exemplary interconnector blank of fig. 6 after processing is complete, in accordance with some embodiments of the present disclosure;

fig. 8 shows a top view of a portion of an illustrative coupling between a bus bar and two battery cells, and a portion of an illustrative fusible coupling between a bus bar and a battery cell, according to some embodiments of the present disclosure;

fig. 9 shows a side view of a portion of an illustrative fusible link between the bus bar and battery cell of fig. 8, according to some embodiments of the present disclosure;

fig. 10 shows a top view of a portion of an illustrative battery interconnect coupled to a plurality of battery cells, in accordance with some embodiments of the present disclosure;

fig. 11 shows a flow diagram of an illustrative process for forming a pressed battery interconnect, according to some embodiments of the present disclosure;

fig. 12 shows a perspective view of an illustrative bus bar blank and foil prior to being adjoined according to some embodiments of the present disclosure;

fig. 13 shows a perspective view of the illustrative bus bar blank and foil of fig. 12 after being abutted, in accordance with some embodiments of the present disclosure;

fig. 14 shows a top view of the exemplary interconnector blank of fig. 13 after trimming, according to some embodiments of the present disclosure;

fig. 15 shows a top view of the exemplary interconnector blank of fig. 14 after separation into individual interconnectors, according to some embodiments of the present disclosure;

figure 16 shows a flow diagram of an illustrative process for forming a battery interconnect by abutting two layers, according to some embodiments of the present disclosure;

fig. 17 shows a bottom view of an illustrative carrier attached to a plurality of battery interconnects in accordance with some embodiments of the present disclosure; and is

Fig. 18 shows a bottom view of the illustrative carrier of fig. 17 without an interconnect attached, in accordance with some embodiments of the present disclosure.

Detailed Description

In some embodiments, the present disclosure relates to a battery interconnect having a desired current capacity, an integrated fusible link, and that can be manufactured using cost effective techniques. In some embodiments, the present disclosure relates to methods for making the battery interconnectors.

In some embodiments, it is desirable for the battery interconnector to include a range of length-scale spatial features. For example, the bus bars (i.e., current collectors) may need to carry a larger current, and therefore have a relatively larger cross-sectional area to reduce ohmic losses. In another example, the fusible link may need to carry a much smaller current and it is desirable to open the circuit when the current is above a threshold, thus requiring a relatively small cross-sectional area. Several techniques in the described implementations are used to address these sometimes disparate length scales.

In some embodiments, the battery interconnector is rough machined using a first manufacturing process, and then processed to form features of a more elongated scale (e.g., fusible links and solderable connections for individual battery cells). For example, the cell interconnector can be stamped or cut to form large scale features, such as bus bars, including a plurality of projections at desired locations. In one or more subsequent processes, the plurality of projections can be pressed (e.g., stamped in a mold to reduce one or more spatial dimensions) and trimmed in alternating steps to form a fusible link suitable for laser welding to the individual battery cells. For illustration, the projections may obtain a small length scale after pressing similar to a foil.

In some embodiments, the battery interconnect is formed by joining two interconnect elements having unique properties to one another. For example, the battery interconnect may be formed by attaching the bus bars to the stamped foil (e.g., via ultrasonic welding, laser welding, pressure and explosive welding, brazing, or any other suitable process). In one or more subsequent processes, portions of the adjoining foils may be trimmed by stamping (e.g., using a cutting die) to form finer features suitable for laser welding to individual battery cells.

The interconnectors described herein (e.g., stacked interconnectors and pressed interconnectors) allow for a reduced number of connections to battery cells as compared to wire bonding. For example, because the bus bar ends of each link are integrated into the bus bar, the number of total connections is halved compared to wire bonding (e.g., only one end of each link needs to be bonded).

Fig. 2 shows a top view of an illustrative battery module 200 having a plurality of battery interconnects (e.g., battery interconnects 211 and 217) disposed between a plurality of battery cells 210, according to some embodiments of the present disclosure. The cells 210 are arranged in an array, which may be a regular pattern (e.g., a hexagonal close-packed arrangement), but is not necessarily a regular pattern. The battery cells 210 are arranged as cell stacks coupled in parallel, and the cell stacks are coupled in series. For example, as shown in FIG. 2, there are six sets of cells coupled in series via

battery interconnects

211 and 217. Each cell is configured to be coupled to two adjacent battery interconnects, with a positive terminal coupled to one adjacent battery interconnect and a negative terminal coupled to another adjacent battery interconnect. The full voltage of the battery module 200 is provided between the

cell interconnectors

211 and 217, and an intermediate voltage exists between any other pair of cell interconnectors. Portion 250 is shown enlarged in fig. 3 to show more detail. It should be understood that the battery module 200 of fig. 2 is shown without a coupling for clarity.

Fig. 3 illustrates an enlarged view of portion 250 from fig. 2, according to some embodiments of the present disclosure. As exemplarily shown in fig. 3, the

battery cells

301 and 302 are configured to be coupled in parallel to the

battery interconnectors

211 and 212. Thus, the positive terminal of each of

battery cells

301 and 302 is configured to be coupled to one of

battery interconnects

211 and 212, and the negative terminal of each of

battery cells

301 and 302 is configured to be coupled to the other of battery interconnects 211 and 212 (e.g., battery interconnects 211 and 212 are in series with each other). Further, battery cell 303 is configured to be coupled in series to both

battery cells

301 and 302. For example, battery cell 303 is configured to be coupled to battery interconnects 213 and 213 (e.g., the positive terminal of battery cell 303 is coupled to one of the battery interconnects, and the negative terminal of battery cell 303 is coupled to the other of the battery interconnects). Thus, each battery cell shown in fig. 3 is configured to be coupled to two battery interconnects. For purposes of illustration, the eight cells of each row include two adjacent groups of four cells connected in parallel, with the left and right groups connected in series. The four battery cells of the left group are connected in parallel with each other, and the four battery cells of the right group are connected in parallel with each other. Thus, interconnect 212 as shown in fig. 3 couples 24 battery cells (e.g., including battery cells 301 and 302) in the left-side group in series with 24 battery cells (e.g., including battery cell 303) in the right-side group.

As exemplarily shown in fig. 2-3, the battery interconnects 211-217 are shaped to reach multiple battery cells, thus exhibiting a branched structure (e.g., a ridge having branches extending to the cells). These battery interconnects include bus bars (e.g., fingers configured to connect to the battery cells via a coupling) that are sized to carry a large amount of current from many battery cells without causing excessively high ohmic losses. The interconnector may include a plurality of finger-like branches coupled together by a spine, where the entire structure will be referred to herein as a busbar. However, the respective connection to the at least one terminal of each battery cell requires a smaller cross-sectional area (e.g., and a corresponding smaller spatial length dimension in at least one dimension) to function as a fusible link. In some embodiments, it is desirable to use a rapid assembly process in order to form a single joint connecting the battery cell to the bus bar. For example, in some embodiments, the joint is made via laser welding. However, while the bus bars must be thick enough to carry sufficient current (e.g., about at least 1mm for aluminum 1100), they cannot be too thick to reliably laser weld (e.g., typically about 0.5mm or less for aluminum 1100). Thus, the coupling between the battery cell and the one or more bus bars may include features of smaller dimensions. In some embodiments, the present disclosure relates to forming such individual connections of each interconnect with a corresponding battery cell. For example, the following description in the context of fig. 4-11 relates to an extruded battery interconnect including a bus bar and a fusible link. In another example, the following description in the context of fig. 12-16 relates to a stacked cell interconnect including a bus bar and a fusible link.

In some cases, it is desirable to avoid the use of multiple components to reduce the cost of the battery pack. The pressed battery interconnector may be formed as a single piece and may include bus bars, fusible links, and other links. In some cases, it is also desirable that the battery interconnector is adapted to laser welding for connection of battery cells. Laser welding is an improvement over wire bonding processes in terms of reliability and manufacturing time. For example, while manufacturing equipment for laser welding may be more expensive, the laser welding process may be performed in parallel when considering production speed, and thus may be more economical. The description of fig. 4-11 provides more detail regarding the pressed battery interconnector.

Fig. 4 illustrates a top view of a portion of

illustrative interconnector blanks

410 and 430, according to some embodiments of the present disclosure. In some embodiments, the

interconnector blanks

410 and 430 may be rough cut (e.g., and will undergo subsequent processing to refine the features). As shown in fig. 4, the

interconnector blanks

410 and 430 are arranged with respect to each other and with respect to the cell 401 for reference, although they need not be arranged during processing (e.g., the processes described in the context of fig. 4-7). In some embodiments, the interconnector blank is formed by stamping, laser cutting, plasma cutting, water jet cutting, machining, any other suitable manufacturing process, or any combination thereof. As exemplarily shown in fig. 4, the

interconnector blanks

410 and 430 have a substantially uniform thickness in the rough-cut station. A uniform thickness is not necessary and the rough-cut interconnector blank may be tapered, stepped, or otherwise have different thicknesses. Further, features in the plane of the interconnector blank (i.e., the plane of axes 490 and 491) may be formed with at least some suitable minimum spatial dimension to ensure machinability. The

interconnector blanks

410 and 430 include

respective bus bars

412 and 432 from which projections may extend. The projections 411 of the interconnector blank 410 and the

projections

431 and 433 of the interconnector blank 430 are intended to be pressed and trimmed to form a coupling (e.g., using the process described in the context of fig. 5-7) for attaching the interconnector blank to the appropriate one of the battery cells 401. In some embodiments, it is not necessary to include the tab 411 as an extension, and a localized portion of the bus bar may be pressed and trimmed at a later stage of processing (e.g., those described in the context of fig. 5-7). Thus, in some embodiments, the cross-sectional area of the bus bar may change slightly (e.g., neck down slightly) when the localized region is pressed to form the coupling.

The plane of the

shafts

490 and 491 is referred to herein as "in-plane". Dimensions such as width and length are primarily mentioned in this plane. A dimension such as thickness is referred to as being perpendicular to the plane (e.g., into the page of fig. 4, as shown).

Fig. 5 shows a top view of portions of the

illustrative interconnector blanks

410 and 430 of fig. 4 after pressing (i.e., now the respective interconnector blanks 510 and 530), according to some embodiments of the present disclosure. In some embodiments, pressing includes placing the interconnector blanks in respective molds, and applying an imprinting process to cause material to flow and deform (i.e., material is not necessarily removed). The resulting

projections

511, 531 and 533 of the interconnector blank 510 and 530 have thicknesses less than the thicknesses of the

projections

411, 431 and 433, respectively. Thus, due to the deformation, the

projections

511, 531, and 531 may have an increased area in the plane defined by the

axes

490 and 491.

Fig. 6 shows a top view of portions of the

illustrative interconnector blanks

510 and 530 of fig. 5 after trimming (i.e., now the respective interconnector blanks 610 and 630), according to some embodiments of the present disclosure. In some embodiments, trimming includes placing the interconnector blanks in respective molds, and applying an imprinting process to shear the material (i.e., the material must be removed). The resulting projections 611 of the interconnector blank 610 and the resulting

projections

631 and 633 of the interconnector blank 630 have thicknesses that are less than the thicknesses of the

projections

411, 431 and 433, respectively, and the areas in the planes of the

axes

490 and 491 decrease from the

projections

511, 531 and 533, respectively. Trimming allows for more precise dimensions to be formed, which can facilitate the formation of a fusible link.

Fig. 7 shows a top view of portions of

illustrative interconnects

710 and 730 after processing is complete, according to some embodiments of the present disclosure. As shown in fig. 7, the

couplers

711, 731, and 733 are formed by the

initial protrusions

411, 431, and 433, respectively, and are configured to be attached to appropriate ones of the cell units 401 (e.g., using laser welding or other suitable processes).

In some embodiments, pressing, trimming, or both may occur more than once in order (e.g., progressive stamping and trimming). For example, the pressing, trimming, or both may be repeated until a desired thickness, shape, or material property (e.g., hardness) is achieved. In some embodiments,

couplings

711, 731, and 733 can be formed using a single process. For example, the mold may be configured to shape and trim a portion of the interconnector blank in a single stamping process. According to some embodiments of the present disclosure, any suitable technique may be used to form a coupling suitable for attachment to a battery cell from a thicker portion of material. The

couplers

711, 731, and 733 may be referred to as stamped tabs because they are materially connected to the bus bars 710 and 730 and have been formed by stamping the material of the bus bars.

As exemplarily shown in fig. 7, each of the

couplings

711 and 733 is configured to be coupled to two respective battery cells in the unit 401. The

links

711 and 733 may, but need not, be fusible links. In some embodiments, the

couplings

711 and 733 may include branches, bifurcations, branches, any other suitable feature for extending to more than one unit, or any combination thereof. Although not shown in fig. 7, in some embodiments,

couplings

711 and 733 can be configured to attach to a single respective battery cell (e.g., and there can be as many as twice as shown in fig. 7).

Although not shown in fig. 4-7, additional couplings may be formed using the processes described in the context of fig. 4-7, which may be used as instrument features, alignment features, measurement features, any other suitable purpose, or any combination thereof. For example, a coupling may be included to serve as a voltage tap, and the coupling may accordingly be configured to have a wire soldered thereto. In another example, a reference circular coupling may be formed to aid in visual or mechanical alignment during installation. In addition to the couplers, any suitable features may be stamped from the interconnector blank.

Fig. 8-10 illustrate exemplary interconnects electrically coupled to battery cells according to some embodiments of the present disclosure. For example, any of the exemplary processes described in the context of fig. 4-7 may be used to form a battery interconnect that may be coupled to a battery cell, as shown in fig. 8-10.

Fig. 8 shows a top view of a portion of an illustrative coupling 811 between a bus bar 810 and two

battery cells

801 and 802, and a portion of an illustrative fusible coupling 813 between the bus bar 810 and the battery cell 803, according to some embodiments of the present disclosure. Links 811 and fusible links 813 can be formed using any of the exemplary processes described in the context of fig. 4-7.

Coupler 811 is attached to

battery cells

801 and 802 at

welds

815 and 816, respectively. For example, in some embodiments, coupling 811 is laser welded to

battery cells

801 and 802, and welds 815 and 816 may be disposed at any suitable location on the interface of coupling 811 and

battery cells

801 and 802. In some embodiments, the coupling may be welded to each battery cell at more than one location. In some embodiments, for example, coupling 811 can be coupled to a first electrode (e.g., a positive electrode or a negative electrode) of

battery cells

801 and 802. In some embodiments, the coupling may be configured to engage to only one battery cell, and thus more couplings may be required (e.g., twice as many). Although not shown in fig. 8, in some embodiments, coupling 811 may include a fusing portion configured to break electrical contact if the combined current from

battery cells

801 and 802 is higher than the fusing current for a suitable amount of time. In some embodiments where the coupling 811 does not include an intended fusing portion, the cross-sectional area at any point of the coupling 811 may necessarily be greater than the cross-sectional area of the corresponding fusible coupling.

The fusible link 813 is attached to the battery cell 803 at weld points 817 and 818, respectively. For example, in some embodiments, coupling 811 is laser welded to

battery cells

801 and 802. In some embodiments, the fusible link may be welded to the battery cell at a single location. In some embodiments, the weld between the fusible link and the battery cell is configured to provide a lower resistance than the fuse portion (e.g., having an effective cross-sectional area greater than the cross-sectional area of the throat), and thus, the fusible link still acts as a fuse at the throat 814 rather than at the weld. The throat 814 includes a local minimum cross-sectional area such that a high current will cause the fusible link 813 to fail at the throat 814 (i.e., where the resistance and corresponding ohmic heating will be greatest). In some implementations, for example, the fusible link 813 can be coupled to a first electrode (e.g., a positive electrode or a negative electrode) of the battery cell 803. In some embodiments, all of the links of the battery system may include fusible links such that each battery cell has two fuses in series (e.g., one fuse per link and one link per positive and negative terminal). The illustrative link 811 and fusible link 813 may be advantageous over wire bonding, for example, because only a single connection point is required for each battery cell (e.g., although more connections may optionally be made) because no bonding is required at the bus bar interface (i.e., the interconnect is a unitary design).

Fig. 9 shows a side view of a portion of an illustrative fusible link 813 between the bus bar 810 and the battery cell 803 of fig. 8, according to some embodiments of the present disclosure. As shown in fig. 9, the bus bar 810 has a relatively large thickness compared to the fusible link 813.

Fig. 10 shows a top view of a portion of an illustrative battery interconnector 1010 coupled to a plurality of battery cells 1001 and a plurality of battery cells 1002 (e.g., with positive center terminals shaded for clarity), according to some embodiments of the present disclosure. The battery interconnector 1010 includes a bus 1013, a coupler 1011, and a fusible coupler 1012. The couplers 1011 are each coupled (e.g., laser welded) to two battery cells 1001 as shown in fig. 10. Fusible links 1012 are each coupled (e.g., laser welded) to one of battery cells 1002 (e.g., twice as many fusible links 1012 as connectors 1011 per battery module, as shown). As exemplarily shown in fig. 10, the

battery cells

1001 and 1002 are connected in series, which are connected by an interconnector 1010. For example, interconnector 1010 is connected to the negative polarity terminal of battery cell 1001 and the positive polarity terminal of battery cell 1002. In the illustrative example, the voltage between the positive polarity terminal of cell 1001 and the negative polarity terminal of cell 1002 connected by interconnect 1010 may be nominally twice the voltage of a single cell. The battery interconnector 1010 includes two different types of couplings (e.g., coupling 1011 and fusible coupling 1012). In accordance with the present disclosure, the battery interconnector can include any suitable number of links, fusible links, and measurement features having any suitable geometric characteristics (e.g., thickness, width, length, shape, cross-sectional area). The battery interconnector may include any suitable material, such as aluminum (e.g., aluminum 1100), copper, steel (e.g., stainless steel), an alloy, any other suitable metal, or any suitable combination thereof. In some embodiments, a battery module may include a plurality of battery interconnects coupled in series, parallel, or a combination thereof to couple a plurality of battery cells to a DC load. It should be understood that although a single interconnector is shown in fig. 10, other interconnectors (not shown) may be included such that each battery cell is connected to two interconnectors. For example, a first other interconnect may be connected to the positive terminal of battery cell 1001 (e.g., via a fusible link), and a second other interconnect may be connected to the negative terminal of battery cell 1002. In another example, other interconnectors may include bus bars (e.g., as illustratively shown in fig. 2) that extend between features of the interconnector 1010.

Fig. 11 shows a flow diagram of an illustrative process 1100 for forming a pressed battery interconnect, according to some embodiments of the present disclosure.

Step 1102 includes forming an interconnector blank. In some embodiments, the interconnector blank is formed by water jet cutting, laser cutting, or plasma cutting a metal plate blank. In some embodiments, the interconnector blank is formed using electrical discharge machining (e.g., wire electrical discharge machining). In some embodiments, the bank of interconnects is formed by stamping a metal plate using a suitable mold to trim out the desired open area. In some embodiments, forming the interconnector blank includes forming large scale features including, for example, current carrying regions and branch regions. The interconnector blank may be similar to the interconnector, but need not be. For example, the bus bar blank may include more than one interconnector arranged as a single component and connected by an area intended for removal in a later process (e.g., not shown, but the interconnectors may be separated by stamping, machining, or any other suitable process). In some embodiments, the interconnector blank may include a tab or other protrusion intended as a coupling (e.g., after pressing). In some embodiments, the interconnector blank need not include projections or other protrusions, and a small area of the blank may be stamped (e.g., to leave a slight recess in the busbar portion). In some embodiments, the interconnector blank may include projections intended as couplings, and the thickness of these projections may be reduced by machining prior to pressing. For example, while achieving a desired coupling thickness by conventional machining is challenging, the thickness of the projections may be halved or otherwise reduced from the thickness of the busbar region, thereby facilitating subsequent pressing.

Step 1104 includes pressing the interconnector blank. In some embodiments, the mold is arranged relative to the interconnector blank and a press is used to press the appropriate areas of the tab or busbar regions into a flatter geometry (e.g., thinner). In some embodiments, step 1104 includes progressive pressing of the appropriate area of the interconnector blank until a desired thickness is reached (e.g., a thickness less than a threshold value). In some embodiments, all of the links of the interconnector blank are pressed in a single operation. In some embodiments, only a subset of the links, or even a single link, is pressed in a single operation (e.g., to provide more control, allow for a simpler mold, require less force, or otherwise ease the process). Contemplated couplings may be pressed to spread out in-plane. For example, for a given volume of material, decreasing the thickness may result in an increase in one or more other spatial dimensions. The coupling may, but need not, have a uniform thickness.

Step 1106 includes trimming the interconnect blank. In some embodiments, step 1106 includes cutting, stamping, shearing, or otherwise reducing the in-plane area of the interconnector blank. For example, step 1106 may include water jet cutting, laser cutting, plasma cutting, electrical discharge machining, stamping, or combinations thereof. In some embodiments, step 1106 includes trimming the coupling to a desired shape and size.

To illustrate, step 1104 may be applied to achieve a desired thickness of the coupling member, while step 1106 is applied to achieve a desired shape and in-plane dimensions of the coupling member. Thus, in some embodiments,

steps

1104 and 1106 may be combined, repeated, or otherwise modified to produce a desired shape. Further,

steps

1104 and 1106 include reshaping or removing the existing material without adding new material. Still further,

steps

1104 and 1106 are performed in the context of a single component, but each of

steps

1104 and 1106 may be performed for all of the links, a portion of the links, or a single link.

The

illustrative steps

1108, 1110, 1112, and 1114 may be performed after forming the links (e.g., by pressing).

Steps

1108, 1110, 1112, and 1114 may be performed in any suitable order, combined, omitted entirely, or otherwise modified in accordance with this disclosure.

Step 1108 includes separating the interconnects. Step 1108 may be performed when the interconnector blank includes more than one desired interconnector, which may be connected to each other by a material (e.g., the interconnector blank includes a continuous material). For example, in embodiments where the interconnect blank is intended as a single interconnect, step 1108 may be omitted. In some embodiments, the interconnector blank includes portions that correspond to the desired interconnector, and portions that may be present for ease of manufacture. For example, the interconnector blank may include a material that provides rigidity between the busbar regions and allows for large forces to be applied to the interconnector blank. After

steps

1104 and 1106 are performed (i.e., when the coupling is formed) and no more force or treatment is required, the additional material can be removed, leaving the desired interconnector blank. Step 1108 may include water jet cutting, laser cutting, plasma cutting, electrical discharge machining, embossing, stamping, or combinations thereof to separate individual interconnects.

Step 1110 includes attaching a carrier to one or more interconnects. The carrier is a cover that maintains the relative arrangement of the interconnectors, protects the interconnectors, and facilitates the mounting of the interconnectors included in the battery system, for example, after formation. The carrier may be desirable because the interconnector includes a coupling which may be susceptible to damage, for example due to its relatively small thickness. In addition, typically the interconnectors must be precisely aligned with the battery cells and with each other prior to attachment to the battery cells. Handling the interconnectors, transporting the interconnectors, arranging the interconnectors with respect to the plurality of battery cells, and attaching the interconnectors to the plurality of battery cells may be achieved by using a carrier.

Step 1110 may be performed on a single interconnect or multiple interconnects (whether already separated or not). Step 1110 may include adhering (e.g., via a suitable adhesive), spot welding (e.g., laser welding, ultrasonic welding, MiG tack welding), latching (e.g., clamps, latches, or other mechanisms for maintaining relative positions), fastening (e.g., with threaded bolts), or any other suitable method for temporarily and releasably attaching a carrier to an interconnector, interconnectors, or an interconnector blank. For example, more details regarding the carrier are described herein in the context of fig. 17-18.

Step 1112 includes measuring the interconnect. In some embodiments, step 1112 includes applying one or more sensors to the interconnector. For example, a thermocouple or a resistance temperature detector may be attached to the interconnect. In some implementations, test leads may be attached to the interconnector. For example, the leads may be attached to the interconnect (e.g., at a measurement coupling that may be formed using any of the exemplary processes described herein) and may be coupled to a control circuit configured to measure a voltage of the interconnect. In another example, each interconnect may be coupled to the control circuit via a test line.

Step 1114 includes attaching one or more interconnectors to the plurality of battery cells. Step 1114 may include arranging one or more interconnectors for attachment. For example, step 1114 may include arranging one or more interconnectors with respect to a plurality of battery cells, aligning one or more interconnectors with each other, aligning one or more interconnectors with battery cells or a subset thereof, aligning one or more interconnectors with reference features of a battery system, any other suitable arrangement considerations, or any combination thereof. When arranged, step 1114 may include welding each coupling to one or more appropriate battery cells of the plurality of battery cells. For example, step 1114 may include laser or ultrasonically welding the coupling member to one or more suitable battery cells.

In some embodiments, for example, step 1114 may be performed after step 1110 while attaching one or more interconnectors to the carrier. Because the carrier provides the handling function and maintains alignment, it may be desirable to hold the carrier in place during attachment of the coupling to the battery cell. In some embodiments, the carrier may include an opening feature that can accommodate a welding device such that welding the coupler to the battery cell can be performed with the carrier in place.

It is contemplated that the steps or descriptions of fig. 11 may be used with any other embodiment of the present disclosure. Further, the steps and descriptions described with respect to fig. 11 may be performed in an alternating order or in parallel for further purposes of this disclosure. For example, the interconnector blank may be trimmed at step 1106 and then pressed at step 1104. Any of these steps may also be skipped or omitted from the process.

In some cases, it is desirable to use a stacked interconnect to achieve current carrying capacity, ease of attaching the interconnect to the battery cell, and fusible link functionality. The stacked cell interconnect may be formed in two or more pieces having different geometric characteristics, which pieces may be joined into layers. In some cases, it is also desirable that the battery interconnector is adapted to laser welding for connection of battery cells. The description of fig. 12-16 provides more detail regarding the stacked cell interconnect.

Including a fuse for each battery cell may be accomplished by laser welding a thin foil of conductive material (i.e., aluminum, copper, or nickel) having a small cross-sectional area (e.g., throat) to one or both of the terminals of the battery cell. Since thin foils are less likely to accommodate the current of multiple cells, it is desirable for the foil to transition to a bus bar having a larger cross-sectional area (e.g., thicker material) to carry the larger current. Since such a transition from a thin foil to a thick bus bar may be difficult to make (e.g., especially when there are so many connections, and the thin foil is difficult to handle), the thin foil is joined to the thicker bus bar, allowing for faster and more cost-effective fabrication (e.g., especially for large batches).

Fig. 12 shows a perspective view of an illustrative bus bar blank 1210 and foil 1220 prior to abutment, according to some embodiments of the present disclosure. The laminated interconnector may be formed from a busbar blank (which may be similar to a rough cut interconnector blank, for example) and a foil (cut or stamped to size, for example). The bus bar blank 1210 can include a single desired interconnect, or more than one desired interconnect (e.g., the interconnects can be separated in a process). For example, the bus bar blank may include the current collecting portion of a single interconnector. In another example, the bus bar blank may include the current collecting portion of several interconnectors, which may be handled as a single part and then separated in a subsequent process for simplicity and cost.

In some embodiments, the busbar blank 1210 includes features 1211 that may include, for example, slots, branches, bifurcations, holes, or other suitable features or combinations thereof as may be desired in an interconnector (e.g., structures having any of the

illustrative interconnectors

211 and 217 of fig. 2).

The foil 1220 is thinner than the bus bar blank 1210 and therefore may be more susceptible to damage. In some embodiments, because the foil 1220 is relatively thin, it may be a flat sheet without cuts, extensions, or other features that may be susceptible to damage. The foil 1220 may be flat, rolled, folded, pleated, or may be provided as a component having any suitable shape, size, and configuration.

The foil 1220 may comprise any suitable electrically conductive material, such as aluminum, copper, or nickel. In some embodiments, the thickness of foil 1220 is determined by the requirements of the bonding process (e.g., laser welding, ultrasonic welding, or resistance welding) used to attach the coupler to the one or more battery cells. Further, the foil 1220 must be thin enough to form a link with the cross-sectional area necessary to act as a fuse under overcurrent conditions. In the illustrative example, the bus bar blank 1210 may be in the range of 2 to 30 times thicker than the foil 1220 to carry the required current without overheating.

Fig. 13 shows a perspective view of the illustrative bus bar blank 1210 and foil 1220 of fig. 12 after abutment, according to some embodiments of the present disclosure. Foil 1220 may be attached to bus bar blank 1210 using any suitable technique, including, for example, laser welding, ultrasonic roll welding, spot welding (e.g., using any suitable welding technique), brazing, soldering, or a combination thereof. In some embodiments, the foils 1220 can be fastened (e.g., using fasteners such as rivets, bolts, or barbs) to the bus bar blank 1210 prior to applying the above-described processes. Welding, brazing, and soldering results in a large contact surface area between the foil 1220 and the bus bar blank 1210, thereby improving electrical conductivity, reducing interface resistance, and providing structural rigidity (e.g., reducing stress concentrations from limited contact). For purposes of discussion, the adjoining foil and bus bar are referred to as an interconnector blank. The adjoining foil 1220 and busbar blank 1210 are referred to as an interconnector blank 1300.

The interconnector blank 1300 comprises two major thicknesses, namely the thickness of the current collecting portion (e.g., busbar blank 1210) and the thickness of the foil (e.g., foil 1220). The foil portion of the interconnector blank 1300 may be trimmed or otherwise formed into a coupling that is configured to be attached to a battery cell. Because the foil is rigidly attached to the bus bar, structural rigidity is improved and the foil is less susceptible to damage, particularly when forming features with finer geometric characteristics (e.g., fusible links).

Fig. 14 illustrates a top view of the exemplary interconnector blank 1300 of fig. 13 after trimming, according to some embodiments of the present disclosure. After trimming, the interconnector blank 1300 is referred to as an interconnector blank 1400, as shown in fig. 14. The interconnector blank 1400 includes

couplings

1411 and 1433, and fusible coupling 1431. As shown, the interconnector blank 1400 is a single piece having two layers, including a thicker layer formed from the busbar blank 1210 and a thinner foil layer formed from the foil 1220. The

areas

1412, 1413, and 1414 are not intended to remain in the final interconnector, but rather are present in the interconnector blank 1400 to provide structural support and maintain the relative positions of the areas of the interconnector blank 1400. For example, rather than stamping individual blanks individually for each interconnector, the interconnector blank 1300 may be stamped in a single mold. In some embodiments, the interconnector blank 1300 is stamped using a progressive die stage to achieve the final form of the

couplings

1411 and 1433 and fusible coupling 1431. A battery unit 1401 is shown as a reference and background in fig. 14. Typically, battery cell 1401 is not preset during formation of the interconnect, and the final interconnect is attached to battery cell 1401 (e.g., as illustratively shown in fig. 15).

Fig. 15 shows a top view of the illustrative interconnector blank 1400 of fig. 14 after separation into individual interconnectors, according to some embodiments of the present disclosure. After the interconnector blank 1400 is separated, as shown in fig. 15, the resulting interconnectors are referred to as

interconnectors

1510 and 1530.

Regions

1412, 1413, and 1414 are removed (e.g., by machining, stamping, or any other suitable process) thereby separating

interconnects

1510 and 1530 and forming electrically independent interconnects. For example, interconnects 1510 and 1530 may then be electrically coupled in series via appropriate battery cells in unit 1401. Additionally,

couplings

1411 and 1433, while similar in shape, are now included in separate interconnects (i.e., interconnects 1510 and 1530, respectively). For example,

couplings

1411 and 1433 and fusible coupling 1431 may be attached to appropriate ones of battery cells 1401 using any suitable process, such as welding (e.g., laser welding or ultrasonic welding).

Interconnectors

1510 and 1530 include current carrying

bus portions

1512 and 1532, respectively, and relatively

thin couplings

1411 and 1433, respectively. Interconnector 1530 includes fusible links 1431, each including a throat configured to act as a fuse and with a suitable fusing current. In some embodiments, the

interconnectors

1510 and 1530, although stacked, may be similar in function (e.g., current distribution and fusing) and form (e.g., thick regions with branches and thin link structures) to the exemplary stamped

interconnectors

710 and 730 of fig. 7. Thus, stamping techniques (e.g., in the context of fig. 4-11) and lamination techniques (e.g., in the context of fig. 12-16) are exemplary techniques for forming an interconnect having desired characteristics.

Fig. 16 shows a flow diagram of an illustrative process 1600 for forming a battery interconnect by abutting two layers, according to some embodiments of the present disclosure.

Step 1602 includes forming a busbar blank. In some embodiments, the busbar blank is formed by machining (e.g., milling, drilling, grinding, or a combination thereof) the metal sheet stock material. In some embodiments, the busbar blank is formed by water jet cutting, laser cutting, or plasma cutting of a metal sheet stock material. In some embodiments, the bus bar blank is formed using electrical discharge machining (e.g., wire electrical discharge machining). In some embodiments, the busbar bank is formed by stamping a metal plate using a suitable mold to trim out the desired open area. In some embodiments, the busbar bank is formed by stamping a metal sheet using (e.g., automated or manual) a turret punch press. In some embodiments, forming the busbar blank includes forming large scale features including, for example, current carrying regions and branch regions. The bus bar blank may be similar to the interconnector, but need not be. For example, the bus bar blank may include more than one interconnector arranged as a single component and connected by an area intended for removal in a later process.

Step 1604 includes forming a foil sheet. In some embodiments, the foil is formed by stamping or cutting a portion of a larger foil. In some embodiments, the metal blank (e.g., plate, bar, or other blank) is flattened until it has a thickness suitable for attachment to a battery cell and formation of a fusible link. The foil need not include any through-going features such as holes, slots or cuts in order to reduce the risk of damage. Further, the foil may include an outer periphery that matches or substantially matches the outer periphery of the bus bar blank. In some embodiments, more than one foil may be applied to the bus bar blank. For example, instead of a single large foil sheet of the same size as the bus bar blank, several foil strips may be formed, which have a similar shape as the bus bar blank when arranged adjacent to each other. In some embodiments, step 1604 may be omitted. For example, the foil need not be trimmed before it is attached to the bus bar blank, and thus the foil may be trimmed along the outer edges of the bus bar blank after attachment.

The foil and the bus bar blank may comprise the same material or different materials. For example, in some embodiments, the foil may comprise aluminum, nickel, or stainless steel, while the bus bar blank may comprise copper, aluminum, or any other suitable conductor (e.g., copper 110, copper 101, aluminum 1100, and/or aluminum 6101). In the illustrative example, aluminum is a suitable material for the foil, as aluminum is well suited for fusing. In another illustrative example, copper has a relatively high electrical conductivity and, therefore, may be included as a bus bar blank that is relatively smaller in thickness (e.g., where there are space limitations) than an aluminum bus bar blank. Any suitable material may be used as a foil or bus bar blank in accordance with the present disclosure. In some embodiments, the foil material has a relatively low melting point, making it suitable for acting as a fuse (e.g., as a fusible link). In some embodiments, the foil material and the bus bar blank material are selected to have similar or otherwise compatible coefficients of thermal expansion.

Step 1606 includes aligning the foil with the busbar blank. In some embodiments, the foil comprises a similar outer shape as the busbar blank and may therefore be aligned with the busbar blank at the outer edge. In some embodiments, the foil, the busbar blank, or both include reference marks to aid in alignment. Step 1606 may include aligning the foil and the busbar blank in a plane (e.g., either or both directions along the interface plane), perpendicular to the plane (e.g., perpendicular to the surface of the foil), or both. In some embodiments, step 1606 includes placing a foil sheet onto the top or bottom of the bus bar blank.

Step 1608 includes attaching the foil blank to the busbar blank. In some embodiments, step 1608 comprises ultrasonic welding (e.g., ultrasonic roll welding). In some embodiments, step 1608 comprises laser welding (e.g., laser welding at multiple locations). In some embodiments, step 1608 comprises brazing or soldering the foil to the bus bar blank. In some embodiments, a combination of techniques may be used to attach the foil blank to the busbar blank.

Step 1610 includes trimming the foil blank to form a foil coupling. In some embodiments, step 1610 includes stamping, stepwise stamping, or other suitable technique to remove the foil material. In some embodiments, step 1610 includes trimming the foil at the outer periphery of the bus bar blank (e.g., when the foil is larger than the bus bar blank, or when the foil has not been previously trimmed). Step 1610 includes forming a link, a fusible link, and optionally measurement features. In some embodiments, some foils remain uncovered by neither the busbar blank nor included in the link or fusible link. For example, step 1610 may include stamping the links and fusible links, and some of the foil material may remain uncovered by the busbar blank. In an illustrative example, step 1610 can include removing sufficient foil material such that electrical shorting between the battery cell terminals, the coupling members, and other nearby metals is less likely to occur at a certain potential difference (e.g., by removing foil beyond the coupling members near the battery terminals).

In the illustrative example, the attached foil and bus bar assembly is disposed at an embossing tool configured to cut and shape all tabs (i.e., couplers) in the foil layer that will be connected to the battery cell terminals. The stamping tool may also be configured to cut the assembly into a desired number of interconnects.

Step 1612 + 1618 (which may be the same as or similar to corresponding step 1108 + 1114 of FIG. 11, for example) may also be applied to the stacked interconnect. For example, the stacked interconnect may be detached at step 1612 (e.g., similar to step 1108), the stacked interconnect may be attached to a carrier at step 1614 (e.g., similar to step 1110), the stacked interconnect may be measured at step 1616 (e.g., similar to step 1112), and the stacked interconnect may be attached to a suitable battery cell at step 1618 (e.g., similar to step 1114).

In an illustrative example of step 1614, the reusable or disposable carrier may be configured to hold all of the individual interconnectors in alignment for transport and mounting onto the battery module. The carrier and interconnect assembly may be attached to the battery module using, for example, fasteners or adhesives. The carrier fixture may then be removed after the mounting fasteners or adhesive is cured, thereby holding the interconnector in place while the carrier is removed.

During processing, a set of interconnects (e.g., intended for a battery module) may be a single rigid piece prior to separation. Upon separation, interconnects that include relatively small features, such as couplers, may be susceptible to damage during storage, transport, and installation in a battery module. To reduce the risk of damage and maintain alignment, a carrier system may be used. The carrier system serves to maintain the alignment (e.g., relative position) of the interconnects and prevent damage to features (e.g., links) on a small length scale. In some cases, it is easier to process and perform as many processes as possible on a single larger workpiece (e.g., including all interconnects for battery modules) until the workpiece needs to be separated into individual components (e.g., individual interconnects). The carrier is configured to hold and maintain the aligned interconnectors after they are separated (e.g., when their relative positions are no longer constrained) until the interconnectors are attached to the battery cells, after which the carrier can be removed. For example, in some embodiments, the carrier comprises a relatively simple adhesive-backed plastic carrier (e.g., similar to a thick sticker and having suitable rigidity). In another example, the carrier may be disposable.

Fig. 17 shows a bottom view of an illustrative carrier 1701 attached to a

battery interconnect

1710 and 1716 according to some embodiments of the present disclosure. Fig. 18 shows a bottom view of the illustrative carrier 1701 of fig. 17 without an interconnect attached, according to some embodiments of the present disclosure. It should be appreciated that, although the couplings are not explicitly shown in fig. 17 for clarity, the

interconnects

1710 and 1716 include suitable couplings (e.g., fusible couplings and non-fusible couplings) formed using any of the exemplary processes disclosed herein.

In some embodiments, as shown in fig. 17, carrier 1701 is attached to interconnects 1710-1716, thereby maintaining the relative positions of interconnects 1710-1716 (e.g., the relative positions desired when installed in a battery system). The illustrative carrier 1701 includes

handles

1703 and 1704, access holes 1702, wire management features 1717, 1718 and 1719, and

positioning features

1720 and 1721. As shown in fig. 17-18, the access holes 1702 are arranged similar to the arrangement of the battery cells to which the

interconnectors

1710 and 1716 are to be attached. In some embodiments, fewer, larger openings are included in place of the access holes 1702. The access hole may comprise a through-going recess of any suitable shape and size configured to allow a through-going passage for attaching the interconnector to the battery cell. The wire management features 1717, 1718, and 1719 are slots, as shown in fig. 17-18. The wire management features 1717 and 1719 may be configured to route wires (e.g., measurement wires, such as voltage taps), secure wires during soldering, or otherwise manage wires that may be present during installation.

Handles

1703 and 1704 are configured to allow transport of the carrier-interconnector assembly. The locating features 1720 and 1721 are configured to align the carrier 1701 to a plurality of battery cells, battery modules, or any other suitable reference. For example, the positioning features 1721 may include circular holes, rectangular holes, slots, tabs, pins, fasteners, any other suitable groove or extension, or any combination thereof, which may aid in positioning the carrier 1701 and the attached

interconnector

1710 and 1716. In some implementations, any or all of the wire management features 1717, 1718, or 1719 may be omitted. In some implementations, either or both of the

handles

1703 and 1704 may be omitted. In some implementations, either or both of the positioning features 1720 and 1721 can be omitted. Any suitable number and type of handles, positioning features, wire management features, and access holes may be included and these components may include any suitable characteristics in accordance with the present disclosure.

The carrier 1701 may comprise any suitable material, such as plastic, rubber, metal, wood, any other suitable material, or any combination thereof. In some embodiments, the carrier 1701 may include a single material arranged in a single layer. In some embodiments, the carrier 1701 includes more than one layer, where each layer includes the same material or different materials. For example, in some embodiments, the carrier may include a relatively rigid layer configured to maintain the shape of the carrier 1701 and a relatively soft material for bonding to the interconnector (e.g., to prevent damage).

To illustrate,

interconnectors

710 and 730, which have been fully formed (e.g., via process 1100 of fig. 11), include

couplings

711, 731, and 733.

Couplings

711, 731, and 733 are relatively thin (e.g., much thinner than bus bars 412 and 432), and handling of

interconnects

710 and 730 may risk damaging the couplings. Furthermore, placing the interconnectors in the battery module for connection to the battery cells may introduce further risks of damage, misalignment, or both. The carrier may be attached to the

interconnectors

710 and 730 after formation to protect the pressed couplings. For example, step 1110 of FIG. 11 may be performed immediately after step 1108 of FIG. 11. The carrier is attached after separation, thereby providing a means to maintain alignment and prepare the interconnector for application to the cell. After the pressed coupling is attached to the appropriate cell terminal (e.g., laser welded), the interconnector is secured to the battery module (e.g., via threaded fasteners, crimps, clamps, or any other securing means), or both, and the carrier can then be removed. For example, the carrier may provide temporary and transitional functionality in maintaining alignment and preventing damage between processing and installation of the interconnect.

To further illustrate,

interconnects

1510 and 1530, which have been fully formed (e.g., via process 1600 of fig. 16), include

couplings

1411, 1431, and 1433.

Couplings

1411, 1431, and 1433 are relatively thin (e.g., the foil is much thinner than bus bars 1512 and 1532), and handling of

interconnectors

1510 and 1530 may risk damaging the couplings. Furthermore, placing the interconnectors in the battery module for connection to the battery cells may introduce further risks of damage, misalignment, or both. The carrier can be attached to the

interconnectors

1510 and 1530 after formation to protect the foil links. For example, step 1614 of fig. 16 may be performed immediately after step 1612 of fig. 16. The carrier is attached after separation, thereby providing a means to maintain alignment and prepare the interconnector for application to the cell. After the foil coupling is attached to the appropriate cell terminal (e.g., laser welded), the interconnector is secured to the battery module (e.g., via threaded fasteners, crimps, clamps, or any other securing means), or both, and the carrier can then be removed. For example, the carrier may provide temporary and transitional functionality in maintaining alignment and preventing damage between processing and installation of the interconnect.

The exemplary techniques of the present disclosure may provide, for example, improved connection success rates, requiring less rework. For example, laser welding has a higher yield than wire bonding in many cases. Furthermore, the exemplary techniques of the present disclosure may provide, for example, increased production speeds. For example, laser welding is much faster than wire bonding. Furthermore, the exemplary techniques of the present disclosure may provide, for example, lower overall production costs. For example, laser welding has a lower unit production cost than wire bonding. Furthermore, exemplary techniques of the present disclosure may provide, for example, personalized fuse current. For example, stamped bus bars may have individually customized fuse dimensions, while wire bonding typically uses fixed diameter wires.

The foregoing merely illustrates the principles of the disclosure and various modifications can be made by those skilled in the art without departing from the scope of the disclosure. The above-described embodiments are presented for purposes of illustration and not limitation. The present disclosure may take many forms in addition to those explicitly described herein. Therefore, it should be emphasized that the present disclosure is not limited to the explicitly disclosed methods, systems, and devices, but is intended to include variations and modifications thereof which are within the spirit of the following claims.

Claims

1. A battery interconnector system comprising:

at least one bus bar;

at least one foil attached to the at least one bus bar at an interface and comprising a first plurality of tabs extending from the interface and configured to contact corresponding terminals of a first plurality of battery cells, wherein each tab of the first plurality of tabs comprises a fusible link.

2. The battery interconnector system of claim 1, wherein the at least one foil is attached to the at least one bus bar at the interface by at least one of ultrasonic welding, laser welding, pressure welding, and explosion welding.

3. The battery interconnector system of claim 1, wherein the at least one bus bar includes a branch.

4. The battery interconnector system of claim 1, wherein each of the respective fusible links comprises a predetermined local minimum cross-sectional area configured to melt at a substantially predetermined current.

5. The battery interconnector system of claim 1, wherein the foil layer further comprises a second plurality of tabs extending from the interface to a second plurality of battery cells.

6. The battery system of claim 5, wherein the first plurality of tabs extend to corresponding terminals of the first plurality of battery cells having a first polarity, and wherein the second plurality of tabs extend to corresponding terminals of the second plurality of battery cells having a second polarity.

7. The battery interconnector system of claim 6, wherein each of the second plurality of tabs extends to two terminals of two of the second plurality of battery cells having the second polarity.

8. The battery interconnector system of claim 1, wherein the at least one bus bar has a first thickness, and wherein the first plurality of tabs has a second thickness, and wherein the second thickness is one quarter of the first thickness or less.

9. The battery interconnector system of claim 8, wherein the second thickness is one tenth or less of the first thickness.

10. The battery interconnector system of claim 1, wherein the at least one bus bar has an in-plane shape, and wherein the at least one foil has substantially the same in-plane shape, and wherein the interfaces are planar and have the same in-plane shape.

11. A battery system, comprising:

a plurality of battery cells grouped into at least one group of battery cells; and

an interconnector coupled to the at least one group of battery cells and including:

a bus bar; and

a foil layer attached to the bus bar at an interface, the foil layer comprising:

a first plurality of tabs extending from the interface to terminals of the at least one group of battery cells, wherein each tab of the first plurality of tabs comprises a fusible link, and wherein each tab of the first plurality of tabs is attached to the terminal.

12. A method for forming a battery interconnect system, the method comprising:

aligning the foil blank with the bus bar;

attaching the foil blank to the bus bar to form an interconnector blank; and

cutting the attached foil blank to form an interconnector, the interconnector comprising a plurality of foil tabs, the plurality of foil tabs comprising at least one fusible link.

13. The method of claim 12, further comprising attaching a carrier to the interconnector and at least one other interconnector to maintain a spatial arrangement of the interconnector and the at least one other interconnector.

14. The method of claim 12, wherein the cutting the foil blank comprises stamping the foil blank to form the plurality of foil tabs.

15. The method of claim 14, wherein the stamping the foil blank comprises progressive stamping the foil blank to form the plurality of foil tabs.

16. The method of claim 12, wherein the at least one fusible link comprises a predetermined cross-sectional area configured to melt at a substantially predetermined current.

17. The method of claim 12, further comprising cutting the interconnector blank after stamping the attached foil blank to form at least two interconnectors.

18. The method of claim 17, wherein cutting the interconnector blank comprises stamping the interconnector blank.

19. The method of claim 17, further comprising attaching a carrier to the at least two interconnectors to maintain a spatial arrangement of the at least two interconnector blanks, and wherein the at least two attached interconnectors are electrically isolated from each other.

20. The method of claim 19, wherein the carrier comprises a plurality of grooves configured to allow attachment of the plurality of foil tabs to a plurality of corresponding battery cells.

21. A battery interconnector system comprising:

at least one bus bar having a first thickness; and

a first plurality of stamped tabs having a second thickness, the first plurality of stamped tabs extending from the bus bar and configured to contact corresponding terminals of a first plurality of battery cells, wherein the first plurality of stamped tabs are connected with the at least one bus bar, wherein each stamped tab of the first plurality of stamped tabs comprises a fusible link, and wherein the second thickness is one quarter or less of the first thickness.

22. The battery interconnector system of claim 21, wherein the at least one bus bar and the first plurality of stamped tabs are formed from a single piece of material.

23. The battery interconnector system of claim 21, wherein each of the respective fusible links comprises a predetermined local minimum cross-sectional area configured to melt at a substantially predetermined current.

24. The battery interconnector system of claim 21, further comprising a second plurality of stamped tabs extending from the bus bar to a second plurality of battery cells.

25. The battery system of claim 24, wherein the first plurality of tabs extend to corresponding terminals of the first plurality of battery cells having a first polarity, and wherein the second plurality of stamped tabs extend to corresponding terminals of the second plurality of battery cells having a second polarity.

26. The battery interconnector system of claim 25, wherein each stamped tab of the second plurality of stamped tabs extends to two terminals of two battery cells of the second plurality of battery cells having the second polarity.

27. The battery interconnector system of claim 21, wherein the first plurality of stamped tabs are formed by pressing a material having the first thickness.

28. The battery interconnector system of claim 21, wherein said second thickness is one tenth or less of said first thickness.

29. The battery interconnector system of claim 21, wherein the at least one bus bar includes one or more branches, and wherein the first plurality of stamped tabs extends from the one or more branches.

30. A battery system, comprising:

a plurality of battery cells grouped into at least one group of battery cells;

at least one bus bar having a first thickness, an

A plurality of stamped tabs having a second thickness, the plurality of stamped tabs extending from the bus bar and configured to contact corresponding terminals of a plurality of battery cells, wherein the plurality of stamped tabs are connected with the at least one bus bar, wherein each stamped tab of the plurality of stamped tabs comprises a fusible link, and wherein the second thickness is one quarter or less of the first thickness.

31. A method for forming a battery interconnect system, the method comprising:

forming an interconnector blank having a first thickness;

pressing a portion of the interconnector blank to form a plurality of green tabs having a second thickness, wherein the second thickness is one quarter or less of the first thickness; and

cutting the plurality of rough tabs to form an interconnector comprising a plurality of tabs comprising at least one fusible link.

32. The method of claim 31, wherein pressing the portion of the interconnector blank comprises progressive pressing and trimming the portion to form the plurality of green tabs.

33. The method of claim 31, further comprising attaching a carrier to the interconnector and at least one other interconnector to maintain a spatial arrangement of the interconnector and the at least one other interconnector.

34. The method of claim 31, wherein the cutting the plurality of green tabs comprises stamping the interconnector blank to form the plurality of tabs.

35. The method of claim 31, wherein the at least one fusible link comprises a predetermined cross-sectional area configured to melt at a substantially predetermined current.

36. The method of claim 31, further comprising cutting the interconnector blank after cutting the plurality of tack tabs to form at least two interconnectors.

37. The method of claim 36, wherein cutting the interconnector blank comprises stamping the interconnector blank.

38. The method of claim 36, further comprising attaching a carrier to the at least two interconnectors to maintain the spatial arrangement of the at least two interconnector blanks, and wherein the at least two attached interconnectors are electrically isolated from each other.

39. The method of claim 38, further comprising attaching the plurality of tabs to a plurality of corresponding battery cells through grooves in the carrier.

40. The method of claim 31, wherein forming the interconnector blank comprises forming a busbar having a plurality of projections, and wherein the portion of the interconnector blank comprises the plurality of projections.