Battery cell tab with features to facilitate alignment and attachment

Abstract

A battery cell includes a housing encapsulating an anode and a cathode, and a first tab electrically connected to the anode or the cathode. The first tab is made of an electrically conductive material and configured to provide an electrical connection between the battery cell and the external component, the first tab including a visualization feature configured to visually indicate a position of the first tab when the first tab is below the other tab.

Description

Technical Field

[0001] The present invention relates to batteries and, more particularly, to assembling battery cells. Background Art

[0002] Battery cells are used in various applications, such as automotive applications (e.g., in electric and hybrid vehicles). For example, electric and hybrid vehicle battery systems include battery modules having multiple battery cells. In some cases, it is desirable to weld or otherwise attach tabs of multiple battery cells to improve battery performance. Summary of the invention

[0003] In an exemplary embodiment, a battery cell includes a housing encapsulating an anode and a cathode, and a first tab electrically connected to the anode or the cathode. The first tab is made of a conductive material and is configured to provide an electrical connection between the battery cell and an external component, and the first tab includes a visualization feature configured to visually indicate a position of the first tab when the first tab is below another tab.

[0004] In addition to one or more features described herein, the visualization feature is a cut-away portion of the first tab, the cut-away portion being a portion of the conductive material removed from the first tab.

[0005] In addition to one or more features described herein, the visual feature is a mitered corner of the first lug.

[0006] In addition to one or more features described herein, the first tab is part of a group of tabs configured to be electrically connected to each other, each tab in the group of tabs including a respective visual feature configured to uniquely identify each tab.

[0007] In addition to one or more features described herein, the battery cell is part of a battery cell pack having a plurality of battery cells electrically connected to each other through respective tabs.

[0008] In addition to one or more features described herein, respective tabs are configured to be stacked, aligned, and joined to electrically connect a plurality of battery cells.

[0009] In addition to one or more features described herein, the respective lugs each have a visual feature configured according to a predetermined sequence or pattern feature.

[0010] In addition to one or more features described herein, the battery cell is part of a battery assembly configured to power an electric motor of a vehicle.

[0011] In another exemplary embodiment, a battery assembly includes a battery cell group including a plurality of battery cells, each of the plurality of battery cells having a tab made of a conductive material and configured to provide an electrical connection between each battery cell and an external component, wherein the tabs of the plurality of battery cells are electrically connected to and aligned with each other. At least one tab of the plurality of battery cells includes a visualization feature configured to visually indicate a position of the at least one tab when the at least one tab is below another tab.

[0012] In addition to one or more features described herein, the visualization feature is a cut-away portion of at least one tab, the cut-away portion being a portion of conductive material removed from the at least one tab.

[0013] In addition to one or more features described herein, the visual feature is a mitered corner of at least one of the lugs.

[0014] In addition to one or more features described herein, each tab of the plurality of battery cells includes a respective visual feature configured to uniquely identify each tab.

[0015] In addition to one or more features described herein, each tab of the plurality of battery cells has a corresponding visual feature configured according to a predetermined sequence or pattern feature.

[0016] In addition to one or more features described herein, the sequence or pattern features are defined by an array of preselected locations that is identical with respect to each lug, and each respective visualization feature is a cut-away portion at a different preselected location.

[0017] In yet another exemplary embodiment, a method of manufacturing a battery cell group includes obtaining a plurality of battery cells, each of the plurality of battery cells having a tab made of a conductive material, stacking the tabs of the plurality of battery cells together, and visually inspecting the stacked tabs, wherein inspecting the stacked tabs includes inspecting a visual feature of at least one tab to determine whether the stacked tabs are properly aligned. The method also includes, based on the stacked tabs being properly aligned, connecting the stacked tabs to provide an electrical connection between each of the plurality of battery cells.

[0018] In addition to one or more features described herein, the visualization feature is a mitered angle of at least one lug of the plurality of lugs.

[0019] In addition to one or more features described herein, visually inspecting the stacked lugs includes determining whether the stacked lugs, including at least one lug having a mitered corner, define a rectangular outline.

[0020] In addition to one or more features described herein, each of the plurality of lugs includes a respective visualization feature, each respective visualization feature being configured according to a predetermined sequence or pattern feature.

[0021] In addition to one or more features described herein, the sequence or pattern features are defined by an array of preselected locations that is identical with respect to each lug, and each respective visualization feature is a cut-away portion at a different preselected location.

[0022] In addition to one or more features described herein, the method also includes assembling the battery cell group as part of a battery assembly configured to power an electric motor of a vehicle.

[0023] The above features and advantages and other features and advantages of the present disclosure will become apparent from the following detailed description when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Other features, advantages and details appear, by way of example only, in the following detailed description, which refers to the accompanying drawings, in which:

[0025] Figure 1 An example of a pouch-type battery cell is depicted;

[0026] Figure 2 An example of a system for manufacturing a battery assembly is depicted;

[0027] Figure 3 depicts a set of battery cell tabs according to an exemplary embodiment, one or more of the battery cell tabs having a visualization feature;

[0028] Figure 4 Depicted in stacked and folded configurations Figure 3 a set of battery cell lugs;

[0029] Figure 5A and 5B depicts a battery cell tab including a sequence for defining a visualization feature according to an exemplary embodiment;

[0030] Figure 6 Depicted is a method according to an exemplary embodiment including Figure 5A and 5B A stack of battery cell tabs defining the visualization features of the sequence;

[0031] Figures 7A-7D Describes aspects of a method of manufacturing a battery cell pack according to an exemplary embodiment; and

[0032] Figure 8 A computer system (eg, an imaging and / or inspection system) according to an embodiment is depicted. DETAILED DESCRIPTION

[0033] The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate the same or corresponding parts and features.

[0034] According to one or more exemplary embodiments, methods, devices, and systems are provided for facilitating the attachment of battery cell tabs, manufacturing battery cell groups, and / or manufacturing battery assemblies. Embodiments of battery cell tabs include at least one visualization feature that allows a user or system to observe and monitor the alignment of a tab relative to one or more other tabs when a group of tabs are attached together. Such attachment can occur, for example, during a manufacturing or assembly process, where battery cells are grouped and electrically connected to form a battery assembly (e.g., a battery cell group and / or a battery module).

[0035] The visualization feature may include a portion of the battery cell tab material that is removed to provide a window or opening that allows the tab to be visualized when the tab is covered by another tab. For example, one or more tabs in a stack of tabs to be connected (e.g., the topmost tab) have a beveled angle that allows a portion of the underlying tab to be seen. In another example, the visualization feature is unique to each tab so that individual tabs can be identified when stacked with other tabs.

[0036] In electric vehicle battery packs (and batteries for other systems and devices), it may be desirable to weld or otherwise join a group of battery cells to connect the group of battery cells in parallel into a battery cell group. The battery cell groups are connected in series within a battery module, which increases the capacity of the module and the associated battery pack. Connecting the battery cells in a battery cell group typically includes stacking and folding the battery cell tabs, followed by connecting the tabs by ultrasonic welding or other suitable connection techniques. It is important to properly align the tabs before connecting. The visualization features described herein help identify missing, damaged, and / or misaligned tabs.

[0037] The embodiments described herein present numerous advantages and technical effects. These embodiments provide an improved manufacturing process that facilitates proper alignment of battery cell tabs. The embodiments ensure that the tabs are properly aligned, thereby avoiding performance issues and risks associated with improperly oriented battery cell tabs.

[0038] Current electrical inspection methods may be limited or ineffective when there is adequate electrical contact between the tabs. At the scaled thickness of most battery cell tabs (e.g., microns), methods using visual indications of thickness may be unreliable. Embodiments allow for higher visual gain when inspecting using visualization features to find defects.

[0039] Figure 1 An example of a battery cell 10 having a terminal tab 24 is depicted. As used herein, a "terminal tab" refers to any conductive component of a battery cell that allows the battery cell to be electrically connected to an external component. For purposes of illustration, Figure 1 An example of a tab connected to a pouch-type battery cell is shown. The embodiments described herein are not limited to any particular type of battery cell, or battery tabs of any particular shape, size, or material. The embodiments may be applicable to prismatic battery cells and other types of battery cells. For example, the embodiments may be used with prismatic pouch external tabs or internal tabs of prismatic or cylindrical can battery cells.

[0040] In this example, the battery cell 10 includes a flexible housing, such as an envelope or bag 12 that is sealed to enclose a plurality of stacked battery cells (battery cell stack). The bag 12 can be an aluminum laminate foil or other suitable bag material. Each battery cell includes a negative electrode or anode 14 and a positive electrode or cathode 16. The anode and cathode are made of a selected conductive material and are configured as a sheet or foil. Each battery cell also includes a separator 18 made of an electrically insulating material such as a polymer or ceramic. Active material 20, such as graphite or a material containing lithium, is disposed in the bag 12 between the layers of the battery cell.

[0041] like Figure 1 As shown, each anode 14 (also referred to as anode foil) extends away from the battery cell, and the anode foils 14 are attached together as a foil stack 22. The foil stack 22 is welded together by, for example, main ultrasonic welding. The foil stack 22 is in turn attached to a conductive tab 24 by a weld 26. The weld 26 can be a solid weld joint formed by ultrasonic welding, or a fusion weld joint formed by laser welding, although other metal-to-metal connection methods can also be used. In this example, the tab 24 is a negative terminal tab. The cathode foil 16 can be similarly welded to a positive tab (not shown) extending outside the bag 12.

[0042] In one embodiment, the tab 24 includes features that facilitate identification and / or visual inspection of the tab 24 when another tab is overlaid on the tab 24. This feature can be applied to one or more tabs in a group of overlapping tabs (a "tab stack"). For example, a group of battery cells can be electrically connected as a battery cell group. One or more battery cells have tabs with visualization features so that each tab to be connected can be visualized even if the tab is located under another tab in the battery cell group. In this way, during manufacturing or assembly, each of the group of tabs can be inspected to ensure proper alignment. The visualization feature can also be used to determine if a tab is missing.

[0043] Note that the embodiments described herein are not limited to Figure 1 For example, the visualization features and inspection methods can be applied to any suitable component of a battery cell or battery assembly. For example, the visualization features described herein can be applied to various foils to ensure proper alignment when forming a foil stack.

[0044] Figure 2 An example of a manufacturing system 50 for manufacturing a battery assembly is depicted. The battery assembly may be a battery module having a plurality of electrically connected battery cells, such as a battery module incorporated into a vehicle (eg, an electric or hybrid vehicle) as part of a battery pack.

[0045] In one embodiment, the battery module includes a plurality of battery cell groups. A "battery cell group" is a group of battery cells electrically connected in parallel by connecting corresponding terminals. The battery cell groups can be connected in series and assembled in a battery module. In an electric vehicle, a plurality of battery modules are typically mounted in a frame or housing and electrically connected to form a battery pack.

[0046] The manufacturing system 50 includes various manufacturing stations that can be controlled or operated by computer systems, human operators, or a combination thereof. As described herein, "station" refers to any number, combination, and layout of equipment, and is not intended to limit the manufacturing system 50 to any particular machine or combination of machines.

[0047] The system 50 includes a battery cell manufacturing station 52 or system that includes various machines for manufacturing individual battery cells. For example, for pouch-shaped battery cells, the manufacturing station includes machines for electrode manufacturing, winding, forming and heat-sealing bags, filling, vacuum sealing, trimming, etc. Note that the system 50 can receive previously built battery cells instead of including battery cell manufacturing.

[0048] The manufacturing system 50 includes various stations and equipment for constructing or assembling battery cells into battery components (e.g., battery cell groups, modules, and battery packs). Examples of the manufacturing system 50 include a cleaning and inspection station 54, a battery cell preparation station 56, a stacking station 58, a grouping station 60, and / or other stations and equipment.

[0049] For example, the battery preparation station 56 includes cutting equipment, such as a laser cutter or a punch, for cutting or trimming the battery cell tabs to facilitate tab connection (e.g., by conforming the tabs in a planned group to the same geometry for welding). The cutting equipment can also be configured to cut visual features from one or more tabs. The battery cell preparation station 56 can also be used to bend the battery cell tabs to facilitate subsequent electrical connection when constructing the battery cell group.

[0050] The battery cells (including one or more battery cells with tabs having visual features) are then transferred to a stacking station 58, where multiple battery cells are stacked together and fixed in a module housing to construct a battery module. The battery modules are then provided to a grouping station 60, where the battery cell tabs are aligned and welded (or otherwise joined) together to form a battery cell group. Upon completion, each battery module can be further assembled into a battery pack or battery system for an electric vehicle.

[0051] Prior to connection, the aligned lugs (lug stack) may be visually inspected to ensure proper alignment. Visual inspection includes inspecting visual features to ensure that each lug is visible and properly positioned.

[0052] Note that the manufacturing system 50 is discussed for purposes of illustration, and the embodiments described herein are not limited to any particular manufacturing process.Any suitable manufacturing system or process that includes some form of battery cell tab stacking may be used.

[0053] The battery cell tabs may be connected in any suitable manner to achieve electrical connection. Examples of connection methods include various welding techniques, such as ultrasonic welding, resistance welding (eg, resistance spot welding or RSW), laser welding, and the like.

[0054] Embodiments of the battery cell include a battery cell tab (e.g., tab 24) that includes one or more features that allow visual inspection of a portion of the tab when the tab is beneath another tab. Features of the tab that allow such visual inspection are referred to as "visualization features."

[0055] The visualization feature can take any suitable form so that when another lug is overlaid on a lug, the visualization feature allows an operator or machine (e.g., an imaging device) to see a portion of the underlying lug. This allows the operator or machine to easily and quickly determine whether the underlying lug is properly positioned or aligned.

[0056] Figure 3-6 Embodiments of battery cell tabs are depicted and various forms of visualization features are shown.

[0057] Figure 3 An embodiment of a visualization feature applied to a set of tabs 24 (represented as tabs 24a, 24b, and 24c) is depicted. In this embodiment, the visualization feature is a beveled or chamfered corner formed by removing a portion of the tab material near the corner of the tab. Although three battery cell tabs are shown, this embodiment may include any number of battery cell tabs.

[0058] Each lug 24 has a different configuration of visualization features such that when the lugs are stacked, a portion of each lug 24a, 24b, and 24c is visible. For example, the uppermost (top) lug 24a has two beveled corners 70 (i.e., beveled corners on each side of the lug 24a). The middle lug 24b has a beveled corner 70 on one side of the lug 24b, and the lowermost (bottom) lug 24c has a beveled corner 70 on the opposite side (opposite to the side of the beveled corner of the lug 24b).

[0059] like Figure 3 As shown, the mitered corners 70 provide visibility of all three lugs 24a, 24b, and 24c in the folded position, allowing for detection of manufacturing errors (eg, missing or crushed lugs).

[0060] Figure 4 A stack of three battery cells and folded tabs 24a, 24b, and 24c are shown, and demonstrate how each battery tab in the tab stack is sufficiently visible so that misalignment can be detected. As shown, tabs 24b and 24c are detectable within the rectangular outline when the tabs are folded.

[0061] The lug stack can be inspected to detect any misalignment or defects. For example, if the corners of the profile are mitered or the profile is not completely rectangular, an operator or imaging system can detect that lug 24b or 24c is incorrectly positioned. Likewise, the inclusion of a visualization feature improves quality control and speed of the manufacturing process.

[0062] The visual features may have any suitable size, shape, or pattern. For example, different lugs may include cutouts of different shapes so that each lug may be individually identifiable. Examples include sawtooth cutouts, square wave cutouts, sinusoidal cutouts, and hole patterns (including circular or other shaped holes).

[0063] In one embodiment, a visualization feature is applied to one or more battery cell tabs to uniquely identify each tab in a set of overlapping tabs. For example, the visualization feature is applied to each tab in a set of tabs according to a predefined pattern or sequence. The pattern or sequence can be a sequence of positions in an area corresponding to each tab area, wherein the visualization feature is applied to a different position of each tab.

[0064] Figure 5A , 5B and 6 depict examples of battery cell tab visualization features. Figure 5A and 5B Lug 24 is shown having features for producing visualization features 70 configured according to a pattern or sequence of cuts. Figure 5AThe pattern is shown as a series of linear cutouts 72 (areas where the lug material has been removed). Although the cutouts 72 are shown as circular, they can have any suitable shape or size. In addition, although the cutouts 72 are shown as being arranged along the top of the lug 24, the cutouts can be positioned or arranged in any direction.

[0065] Figure 5B The lug 24 is shown in a state where one of the cutouts 72 has been formed by stamping or otherwise removing material at one location in the sequence, indicated as cutout location 74. A visual feature may be created by forming the cutout 72 at each location 74 except for a selected location. In this example, the cutout 72 forms a unique visual feature.

[0066] Figure 6 An example of a set of lugs 24a, 24b, and 24c having visualization features formed according to a predetermined sequence or pattern is shown. In this example, the visualization features of each lug are formed by providing a series of cutouts 72 on each lug and keeping different positions 74 intact. As shown, lug 24a has a visualization feature in the form of a complete position 74a, lug 24b has a visualization feature in the form of a complete position 74b, and lug 24c has a visualization feature in the form of a complete position 74c. Each complete position is different and can correspond to a predetermined position in the sequence.

[0067] A lug stack, such as the lug stack formed by lugs 24a, 24b, and 24c, may be inspected after stacking to ensure proper alignment before welding or otherwise connecting the lugs. Figure 6 When the lugs 24a-c are stacked and aligned, the complete locations 74a, 74c and 74c should be arranged along the top of the lug stack so that a specific pattern of complete locations can be seen. If the visual feature is not visible (e.g., one of the lugs is missing, so that a hole is seen where the complete location 74 should be), or is seen in an unexpected position, the lugs 24a-24c are not properly aligned. Incorrect alignment can be detected in this way.

[0068] The battery cell tabs may include one or more visual indicators to facilitate inspection of the battery cell tabs when stacked. The visual indicators may be colors, markings (e.g., symbols, numeric indicators, and / or text indicators), or any other visual features that allow identification of individual tabs. The tabs may include a visual indicator at one or more locations on the tabs such that the visual indicators are visible when stacked.

[0069] Figures 7A-7DDepicted are stages of manufacturing of a battery cell group, and depicted are aspects of examples of processes performed during manufacturing. These processes may be performed by one or more stations of the manufacturing system 50, or using any suitable equipment.

[0070] Fig. 7A The battery cell 10 (designated as battery cell 10a) is shown after the tab 24 (designated as tab 24a) has been trimmed and after the tab 24a has been bent to accommodate subsequent connection of tabs of a group of battery cells. Figure 7B A group of battery cells 10 (designated as battery cells 10a, 10b, and 10c) are shown, each having a corresponding terminal tab 24 (designated as terminal tab 24a, 24b, and 24c). As shown, the terminal tabs 24a and 24c are bent so that the terminal tabs 24a-24c can be stacked and connected.

[0071] like Figure 7C As shown, the battery cell tabs 24a-24c are bent or folded to conform to the bus bar 80 and are prepared for welding. To connect the tabs, the folded tabs are clamped to the bus bar 80 to flatten the battery cell, as shown in FIG. Fig.7D and then welded together.

[0072] Figure 8 Aspects of an embodiment of a computer system 140 are shown that can perform various aspects of the embodiments described herein. The computer system 140 includes at least one processing device 142, which typically includes one or more processors, for performing various aspects of the image acquisition and analysis methods described herein.

[0073] Components of the computer system 140 include a processing device 142 (such as one or more processors or processing units), a memory 144, and a bus 146 that couples various system components including the system memory 144 to the processing device 142. The system memory 144 may include various computer system readable media. Such media may be any available media that can be accessed by the processing device 142, and includes both volatile and non-volatile media, and removable and non-removable media.

[0074] For example, system memory 144 includes nonvolatile memory 148, such as a hard drive, and may also include volatile memory 150, such as random access memory (RAM) and / or cache memory. Computer system 140 may also include other removable / non-removable, volatile / nonvolatile computer system storage media.

[0075] The system memory 144 may include at least one program product having a set (e.g., at least one) of program modules configured to perform the functions of the embodiments described herein. For example, the system memory 144 stores various program modules that generally perform the functions and / or methods of the embodiments described herein. One or more modules 152 may be included to perform functions related to forming visualization features (e.g., a laser cutting control system). An inspection module 154 may be included for imaging and inspecting battery cell tabs and stacking. The system 140 is not limited thereto, as other modules may be included. As used herein, the term "module" refers to a processing circuit, which may include an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that executes one or more software or firmware programs, a combinational logic circuit, and / or other suitable components that provide the functions.

[0076] Processing device 142 may also communicate with one or more external devices 156, which may be keyboards, pointing devices, and / or any device that enables processing device 142 to communicate with one or more other computing devices (e.g., network cards, modems, etc.). Communications with various devices may occur through input / output (I / O) interfaces 164 and 165.

[0077] The processing device 142 may also communicate with one or more networks 166, such as a local area network (LAN), a general wide area network (WAN), a bus network, and / or a public network (e.g., the Internet) via a network adapter 168. It should be understood that, although not shown, other hardware and / or software components may be used in conjunction with the computer system 40. Examples include, but are not limited to, microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, and data archival storage systems, etc.

[0078] The terms "one" and "an" do not indicate a limitation of quantity, but rather indicate the presence of at least one of the referenced items. The term "or" means "and / or", unless the context clearly indicates otherwise. References to "an aspect" throughout the specification mean that a particular element (e.g., feature, structure, step, or characteristic) described in conjunction with that aspect is included in at least one aspect described herein, and may or may not be present in other aspects. In addition, it should be understood that the described elements may be combined in any suitable manner in various aspects.

[0079] When an element such as a layer, film, region, or substrate is referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present.

[0080] Unless otherwise indicated herein, all test standards are the most recent standards in effect as of the filing date of the present application or, if priority is claimed, the filing date of the earliest priority application in which the test standards appear.

[0081] Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0082] Although the above disclosure has been described with reference to exemplary embodiments, it will be appreciated by those skilled in the art that various changes may be made and equivalents may be substituted for its elements without departing from the scope thereof. In addition, many modifications may be made to adapt specific situations or materials to the teachings of the disclosure without departing from the essential scope of the disclosure. Therefore, it is intended that the disclosure is not limited to the specific embodiments disclosed, but will include all embodiments falling within its scope.

Claims

1. A battery cell, comprising: A casing encapsulating the anode and cathode; as well as A first terminal tab is electrically connected to the anode or cathode, the first terminal tab is made of a conductive material and is configured to provide an electrical connection between the battery cell and an external component, the first terminal tab includes a visualization feature, and the visualization feature is configured to visually indicate the position of the first terminal tab when the first terminal tab is below another terminal tab.

2. The battery cell according to claim 1, wherein: The visualization feature is a cut-away portion of the first tab, the cut-away portion being a portion of conductive material removed from the first tab.

3. The battery cell according to claim 2, wherein: The visual feature is a mitered angle of the first lug.

4. The battery cell according to claim 1, wherein: The first lug is part of a group of lugs configured to be electrically connected to each other, each lug in the group of lugs comprising a respective visual feature configured to uniquely identify each lug.

5. The battery cell according to claim 1, wherein: The battery cell is part of a battery cell group having a plurality of battery cells electrically connected to each other through respective tabs.

6. The battery cell according to claim 5, wherein: The respective tabs are configured to be stacked, aligned, and engaged to electrically connect the plurality of battery cells.

7. The battery cell according to claim 6, wherein: The respective lugs each have a visual feature configured according to a predetermined sequence or pattern of features.

8. The battery cell according to claim 1, wherein: The battery cell is part of a battery assembly configured to power an electric motor of a vehicle.

9. A battery assembly comprising: A battery cell group includes a plurality of battery cells, each of the plurality of battery cells having a terminal tab made of a conductive material and configured to provide an electrical connection between each battery cell and an external component, wherein the terminal tabs of the plurality of battery cells are electrically connected and aligned with each other, and wherein at least one of the plurality of battery cells includes a visualization feature, the visualization feature being configured to visually indicate a position of at least one tab when the at least one tab is below another tab.

10. The battery assembly according to claim 9, wherein: The visualization feature is a cut-away portion of the at least one tab, the cut-away portion being a portion of conductive material removed from the at least one tab.

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