Battery current collector direct wire sheet welding

Abstract

A system for electrically connecting tabs of a battery cell includes an electrically conductive welding plate configured to be disposed within a housing of the battery cell and electrically connected to a tab stack formed of a plurality of tabs extending from electrode layers of a stack of battery cells, the welding plate having a welding surface, an electrode assembly includes a tab stack having a welding surface at least partially oriented along a vertical direction parallel to a surface of an electrode layer forming an electrode stack, and a welding device configured to weld the tab stack to the welding surface and form at least a portion of a connector. The tab stack is soldered while maintaining the tab stack in a planar configuration and an undeformed state.

Description

Technical Field

[0001] The present disclosure relates to batteries, and more particularly to the manufacture and assembly of 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. The battery cells can be prismatic cells or other types of battery cells and typically include multiple layers of anode material and cathode material. The anode layers are electrically connected by welding a stack of anode tabs, and the cathode layers are electrically connected by welding a stack of cathode tabs. Summary of the Invention

[0003] In one exemplary embodiment, a system for electrically connecting tabs of a battery cell includes a conductive welding plate configured to be disposed within a battery cell housing and electrically connected to a tab stack formed by a plurality of tabs extending from electrode layers of a battery cell stack, the welding plate having a welding surface at least partially oriented in a vertical direction parallel to surfaces of the electrode layers forming the electrode stack, and a welding device configured to weld the tab stack to the welding surface and form at least a portion of a connector. The tab stack is welded while maintaining the tab stack in a planar configuration and an undeformed state.

[0004] In addition to one or more features described herein, the undeformed state is a state in which the tab stack is not folded prior to welding and is not subjected to bending forces during welding.

[0005] In addition to one or more features described herein, the welding apparatus is configured to perform a welding method comprising at least one of ultrasonic welding and laser welding, the welding apparatus comprises at least one of a laser welding apparatus and an ultrasonic welding apparatus, the ultrasonic welding apparatus comprising a sonotrode configured to engage the tab stack and the weld surface.

[0006] In addition to one or more features described herein, the welding surface includes a textured pattern to facilitate welding the lug stack to the welding plate.

[0007] In addition to one or more features described herein, the lug stack includes a first lug stack and a second lug stack formed by a plurality of lugs, and the welding surface includes a pair of opposing welding surfaces, each of the opposing welding surfaces being configured for welding one of the first lug stack and the second lug stack to a welding plate.

[0008] In addition to one or more features described herein, the system includes an actuator configured to move the welding plate in the vertical direction, the actuator being controllable to move the welding plate in the vertical direction toward the battery cell stack after welding to relieve stress on portions of the plurality of tabs between the battery cell stack and the tab stack.

[0009] In addition to one or more features described herein, the housing is a rigid housing.

[0010] In addition to one or more features described herein, the system also includes a joining device configured to engage the plurality of lugs and join the plurality of lugs together in a planar configuration to form a lug stack.

[0011] In another exemplary embodiment, a method of electrically connecting tabs of a battery cell includes obtaining a battery cell stack configured to be disposed in a housing to form a battery cell, wherein a plurality of tabs extend from electrode layers of the battery cell stack, and forming a tab stack from portions of the plurality of tabs, and disposing the tab stack against a welding surface of a welding plate configured to be disposed within the housing, the welding surface being at least partially oriented in a vertical direction. The vertical direction is parallel to surfaces of the electrode layers forming the electrode stack. The method further includes welding the tab stack to the welding surface by a welding device to form at least a portion of a connector, wherein the tab stack is welded while maintaining the tab stack in a planar configuration and an undeformed state.

[0012] In addition to one or more features described herein, the undeformed state is a state in which the tab stack is not folded prior to welding and is not subjected to bending forces during welding.

[0013] In addition to one or more features described herein, the welding apparatus is configured to perform a welding method comprising at least one of ultrasonic welding and laser welding, the welding apparatus comprises at least one of a laser welding apparatus and an ultrasonic welding apparatus, the ultrasonic welding apparatus comprising a sonotrode configured to engage the tab stack and the weld surface.

[0014] In addition to one or more features described herein, the welding surface includes a textured pattern to facilitate welding the lug stack to the welding plate.

[0015] In addition to one or more of the features described herein, the lug stack includes a first lug stack and a second lug stack formed from a plurality of lugs, the welding surface includes a pair of opposing welding surfaces, and welding the lug stack includes welding the first lug stack to one of the pair of opposing surfaces and welding the second lug stack to the other of the pair of opposing surfaces.

[0016] In addition to one or more features described herein, the method includes moving the welding plate in a vertical direction toward the battery cell stack after welding to relieve stress on portions of the plurality of tabs between the battery cell stack and the tab stack.

[0017] In addition to one or more features described herein, the method includes deflecting excess portions of the plurality of lugs, the excess portions including a portion of each lug above the weld lug stack, wherein the deflecting includes imparting a curvature to the excess portions.

[0018] In another exemplary embodiment, a computer program product includes a computer-readable memory having computer-executable instructions stored thereon, the computer-executable instructions, when executed by a processor, causing the processor to perform operations. The operations include obtaining a battery cell stack configured to be disposed in a housing to form a battery cell, wherein a plurality of tabs extend from electrode layers of the battery cell stack, a tab stack formed by portions of the plurality of tabs, and disposing the tab stack against a welding surface of a welding plate configured to be disposed within the housing of the battery cell, the welding surface being at least partially oriented along a vertical direction parallel to surfaces of the electrode layers forming the electrode stack. The operations also include welding the tab stack to the welding surface using a welding device to form at least a portion of a connector, wherein the welding of the tab stack is performed while maintaining the tab stack in a planar configuration and an undeformed state.

[0019] In addition to one or more features described herein, the undeformed state is a state in which the tab stack is not folded prior to welding and is not subjected to bending forces during welding.

[0020] In addition to one or more features described herein, the welding apparatus includes an ultrasonic welding apparatus including a sonotrode configured to engage the tab stack and the weld surface, and the weld surface includes a textured pattern to facilitate welding of the tab stack to the weld plate.

[0021] In addition to one or more features described herein, the operations include moving the welding plate in a vertical direction toward the battery cell stack after welding to relieve stress on portions of the plurality of tabs between the battery cell stack and the tab stack.

[0022] In addition to one or more features described herein, the operations include joining the plurality of lugs by a joining device, and joining the plurality of lugs together in a planar configuration to form a lug stack prior to welding.

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

[0024] Additional 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 battery cell is depicted;

[0026] Figure 2 An example of a battery cell is depicted;

[0027] Figure 3 depicts a system for manufacturing battery cells according to an exemplary embodiment;

[0028] Figure 4 depicts components of a battery cell and components of a system for electrically connecting tabs of a battery cell according to an exemplary embodiment;

[0029] Figure 5A and 5B depicts components of a battery cell and components of a system for electrically connecting tabs of a battery cell according to an exemplary embodiment;

[0030] Figures 6A-6F Aspects of methods of electrically connecting battery cell tabs and manufacturing battery cells are depicted;

[0031] Figure 7 Depicts a method for joining a tab stack of a battery cell to a Figure 4 An example of a laser welding process for welding plates of a system;

[0032] Figure 8 Depicts a method for joining a tab stack of a battery cell to a Figure 4 An example of a laser welding process for welding plates of a system;

[0033] Figure 9 Depicts a method for joining a tab stack of a battery cell to a Figure 4An example of a system for welding plates in a combined laser and ultrasonic welding process;

[0034] Figure 10 Depicted are components of a battery cell and a system for electrically connecting tabs of a battery cell, the system including a connection assembly having a deflection feature for deflecting excess tab portions, according to an exemplary embodiment;

[0035] Figure 11 Depicted are components of a battery cell and components of a system for electrically connecting tabs of a battery cell, the system including a connection assembly having a deflection device for deflecting excess tab portions, according to exemplary embodiments; and

[0036] Figures 12A-12F Depicts the use of an exemplary embodiment Figure 11 Aspects of a method of transferring excess tab portions, electrically connecting battery cell tabs, and manufacturing battery cells are disclosed. DETAILED DESCRIPTION

[0037] The following description is merely exemplary in nature and is in no way intended to limit the present disclosure, its application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0038] According to one or more exemplary embodiments, methods, devices, and systems are provided for facilitating the attachment and electrical connection of electrodes (anodes and cathodes) in battery cells. Embodiments of the system for consolidating and connecting portions of electrodes or electrode layers include a connection assembly configured to perform functions associated with forming a battery tab stack, welding the tab stack, and forming connectors for the battery cells.

[0039] One embodiment of a connection assembly includes an internal terminal welding plate (also referred to as an internal welding plate) configured to weld the tabs in a tab stack together when the tab stack is in a planar form. The tab stack is in a "planar form" when the tab stack (or at least a portion of the tab stack that is being welded) is vertically or otherwise linearly oriented. Thus, the tab stack can be welded or connected without folding any portion of the tab stack (e.g., any portion that is being welded) and without deforming due to bending forces. Excess tab portions (i.e., portions above the weld) can be handled by trimming, deflecting, or other suitable techniques.

[0040] The internal weld plate defines one or more flat or planar weld surfaces configured to maintain the lug stack in a flat and / or undeformed state during welding. In one embodiment, the lug stack is welded by ultrasonic welding, and the weld surfaces each include a textured surface for improving weld quality.

[0041] The internal welding plate can include additional features, such as rounded edges, to avoid tearing or other damage to the tabs. The internal welding plate can be connected to an actuator for moving the welding plate before and / or after welding. For example, the welding plate can be moved in an upward direction (away from the battery cell stack) to provide tension and ensure that the tabs making up the tab stack are properly aligned, and moved in a downward direction after welding to relieve strain (e.g., by allowing some portions of the tabs between the tab stack and the battery cell stack to bend and provide relaxation to relieve stress). The "upward" direction is defined herein as a direction pointing away from the battery cell stack (e.g., parallel to the electrode layers in the battery cell stack or along a plane defined by the electrode layer surfaces), and the "downward" direction is defined as a direction pointing toward the battery cell stack (e.g., parallel to the electrode layers or along a plane defined by the electrode layer surfaces).

[0042] The embodiments described herein present numerous advantages and technical effects. The embodiments provide an improved manufacturing process that facilitates proper attachment and electrical connection of electrode tabs. For example, the embodiments described herein allow for the formation and welding of tab stacks without the need for folding, which reduces the likelihood of tearing or other damage. Furthermore, the embodiments reduce stress on the tab layers during welding.

[0043] Figure 1 and Figure 2 An example of a battery cell 10 is depicted. The battery cell includes a housing 12, which can be a rigid housing designed for a prismatic battery cell. For example, the housing can be a rectangular shell or "can" made of aluminum or other material. The embodiments described herein are not limited to any particular type of battery cell, or electrodes and housings of any particular shape, size, or material. For example, the embodiments can be adapted for battery cells having various types of housings.

[0044] The battery cell 10 includes multiple layers that form a negative electrode or anode and a positive electrode or cathode. The anode is made of a conductive anode layer 14, and the cathode is made of a conductive cathode layer 16. The anode layer 14 and the cathode layer 16 are configured as thin sheets or foils. A separator 18 made of an electrically insulating material (e.g., a polymer or ceramic) is disposed between each anode layer 14 and the adjacent cathode layer 16. An active material 20 (such as graphite or a material including lithium) is disposed in the outer casing 12 and between the layers. These inner layers constitute the battery cell stack 22.

[0045] It should be noted that the number of electrodes is not limited to Figure 1 The battery cell 10 may have any number of anode layers 14 and any number of cathode layers 16. For example, the battery cell 10 may have hundreds of individual foil layers forming the electrode layers.

[0046] like Figure 1 As shown, each anode layer 14 includes a portion 24 that extends away from the interior of the battery cell 10 and allows each anode layer 14 to be electrically connected to another anode layer 14. This portion 24 is also referred to as a tab 24 or a connecting tab 24. Although not shown, the cathode layer 16 includes a tab so that the cathode layer 16 can be connected. The cathode layer tab (not shown) can extend from the end opposite to the anode tab 24 (in the z direction) or from the same end (e.g., as shown in FIG. Figure 6A shown).

[0047] Some portions (or subsets thereof) of the tabs 24 are stacked together as at least one tab stack 26. The portions comprising each tab stack 26 are welded together, for example, by ultrasonic welding. In one embodiment, the weld is a solid-state weld joint formed by ultrasonic welding. The battery cell 10 is not limited thereto, as other techniques, such as laser welding and other metal-to-metal joining processes, may be used.

[0048] Each tab stack 26 is welded to a conductive member 28 ("welding plate") that provides a contact point for welding the tab stacks 26 together and can serve as at least a portion of a connector. The connector forms the negative terminal. Cathode layer 16 can be similarly welded to a positive terminal (not shown) extending outside of housing 12. Welding plate 28 can form a connector alone or in combination with other electrical conductors.

[0049] The welding plate 28 includes at least one welding surface 30. The welding surface 30 serves as a base and provides welding contact where the tab stack 26 is welded to the welding plate 28. Each welding surface 30 is configured to provide a base that allows the tab stack 26 to be welded without folding, deflecting, or otherwise applying bending forces (as opposed to tension that may be applied during welding) to some portions of the tab stack (i.e., those portions that are welded to each other and to the welding plate 28). In one embodiment, each welding surface 30 is a generally flat surface that may have features disposed on or integral to the surface (e.g., to facilitate ultrasonic welding and described further herein).

[0050] Figure 1An example is shown in which the tabs 24 are gathered and connected into a single tab stack 26 for the anode layer 14 (a single tab stack for connecting the cathode layer may be similarly formed). Figure 2 An example is shown in which the lugs 24 are grouped into two separate lug stacks 24 (designated as lug stacks 24a and 24b), each lug stack 24 being welded to a respective surface 30 (designated as surfaces 30b).

[0051] As discussed further herein, each surface 30 (either a single surface 30 or surfaces 30a and 30b) is a flat surface that can be oriented along a vertical direction (z-axis) such that each surface 30 is at least substantially parallel to a surface of an electrode layer. Each surface 30 can be completely or substantially vertical, or can be oriented at an angle relative to vertical (less than 90 degrees relative to the battery cell stack). In this manner, each tab stack 26 is formed or welded to avoid folding, as compared to conventional manufacturing processes.

[0052] Figure 3 An example of a manufacturing system 40 for manufacturing battery cells is depicted. Manufacturing system 40 includes various manufacturing stations that can be controlled or operated by computer systems, human operators, or a combination thereof. As used herein, "station" refers to any number, combination, and arrangement of equipment and is not intended to limit manufacturing system 40 to any particular machine or combination of machines.

[0053] The manufacturing system 40 includes, for example, an active material processing station 42 for preparing active materials to be applied to the electrode layers. The system 40 may also include a coating station 44 for coating the electrodes with the active materials. The manufacturing system 40 also includes an electrode cutting station 45, which can be used to form electrode layers and tabs from sheets of electrode material (e.g., copper and aluminum sheets).

[0054] The system 40 also includes a stacking station 46 for forming the various layers of the battery cell stack and a welding station 48 for welding the electrode layer tabs. The welding station 48 may include a welding plate 28 as described herein in combination with welding equipment.

[0055] System 40 may include or be connected to one or more processing devices for performing various aspects of manufacturing. For example, welding station 48 is connected to controller 49 for controlling processes such as bonding, trimming, deflection of excess lug portions, and / or welding.

[0056] The system 40 may include other stations for performing subsequent processes to complete the battery cells. Examples include assembly stations (e.g., for battery cell packaging or housing construction, sealing, electrolyte filling, etc.) and stations for manufacturing battery components (such as battery packs and / or modules).

[0057] For example, the battery cells may be mounted in a battery assembly. A 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 vehicle or a hybrid vehicle) as part of a battery pack.

[0058] Figure 4 Components of an embodiment of a system for electrically connecting a lug stack to a welding plate or other connector are depicted. The system includes a lug connection assembly 50 that includes a welding plate 28. In this embodiment, the welding plate 28 is an internal terminal welding plate 28 that is configured to be disposed within a housing (e.g., Figure 1 and Figure 2 prismatic housing 12).

[0059] The welding plate 28 defines one or more connecting members 52 that are elongated in the vertical direction and provide the welding surface 30. There may be one connecting member 52 (as shown by opposing connecting members 52a and 52b) or any desired number of connecting members.

[0060] For example, each connecting member 52a, 52b defines a corresponding welding surface 30a, 30b that extends perpendicularly and parallel to the surface of the battery cell stack 22. The welding surfaces 30a, 30b can be partially parallel and, therefore, can define an angle of less than 90 degrees relative to the battery cell stack surface. Each connecting member 52a, 52b can have rounded edges or be otherwise configured so that there are no sharp edges that could cause tearing.

[0061] In one embodiment, each welding surface 30a, 30b is configured to facilitate ultrasonic welding. Ultrasonic welding generally involves applying high-frequency ultrasonic acoustic vibrations using a sonotrode 54. Each surface 30a, 30b serves as a contact surface (anvil), and when welding, the wafer stack 26 is held between the sonotrode 54 and the surface 30.

[0062] To improve the quality of the ultrasonic weld, each welding surface 30a, 30b includes one or more features integrated therewith that serve to improve the quality of the bond formed by the welding process. Figure 4 As shown, surface 30 includes a textured pattern 56 of bumps, grooves, ridges, protrusions, dimples, or other surface features. Surface 30a may also include raised areas 58 corresponding to weld areas. Surface 30b may also have a similar pattern 56.

[0063] After the welding process is completed, a connector formed of a conductive material (and configured to provide an electrical connection between the anode layer and the device to be powered) may be connected to the welding plate 28 .

[0064] In one embodiment, the connection assembly 50 includes the welding plate 28 and one or more additional components attached to (or integral with) the welding plate 28. All components of the connection assembly 50 are movable as a unit.

[0065] For example, the connection assembly 50 includes a welding plate 28 and an attached cover plate 60 that forms part of the cover of the battery assembly. Other components (e.g., insulating inserts 62, feedthroughs, terminals, etc.) may also be coupled to the welding plate 28 to form the connection assembly 50.

[0066] Figure 5A and 5B An embodiment of the connection assembly 50 is depicted that includes a retaining device 64 . Figure 5A is a cross section along the xz plane defined by the x-axis and the z-axis, and Figure 5B is a cross section along the yz plane defined by the y-axis and the z-axis.

[0067] The retaining device 64 is configured to be disposed around portions of the welding plate 28, the cover plate 60, and the insert 62. Figure 5B As shown, the retaining device 64 includes an upper plate 66 and opposing arms 68 that hold the welding plate 28, cover plate 60, and insert 62 in place, such as during welding. The retaining device 64 can be removed after welding by sliding the retaining device 64 along the x-axis.

[0068] Figures 6A-6F Aspects of a method of manufacturing a battery cell are shown. The method (or portions thereof) may be performed by any suitable one or more processing devices, such as, but not limited to, one or more controllers of the manufacturing system 40 (e.g., controller 49 connected to the welding station 48) and / or the connection system 50.

[0069] The method includes a plurality of steps or phases. The method is not limited to the number or order of the steps therein, as some steps may be performed in a different order than described below, or fewer than all steps may be performed.

[0070] The method is described by joining anode tabs to form a tab stack and welding the anode tabs to the anode welding plate. It should be understood that the method is similarly applicable to cathode tabs.

[0071] In the first stage, reference Figure 6A , forming or obtaining an electrode, which includes an anode sheet and a cathode sheet made of a coated conductive material. For example, the anode sheet is made of copper and the cathode sheet is made of aluminum.

[0072] The anode and cathode sheets are coated, cut, trimmed, and / or otherwise processed to produce anode and cathode layers, and the anode and cathode layers are assembled with other layers (e.g., separator layers) to form the battery cell stack 22. Each anode and cathode layer has a corresponding tab extending from the battery cell stack.

[0073] like Figure 6A As shown, the anode tab 24 and the cathode tab 25 extend from the same end or side of the battery cell stack 22. The approach is not limited in this regard, as the anode tab and cathode tab may extend from opposite ends or sides, or be otherwise positioned as desired.

[0074] In the second stage, reference Figure 6B The anode tabs 24 are divided into two groups of tabs 24a and 24b. Each group of tabs 24a and 24b is inserted through a connecting device having multiple sets of clamps 70. A portion of each group of tabs disposed between a set of clamps forms a tab stack 26a, 26b. Some portions of the tab group above the clamps 70 are referred to as excess portions 29a, 29b. Each set of clamps 70 includes opposing bodies with flat ends that are brought together to compress the corresponding tab stacks 26a, 26b, thereby joining the tab layers together as a flat stack. The tab stacks can be joined by extrusion, application of heat, and / or other suitable techniques.

[0075] In the third stage, see Figure 6C , excess portions 29a, 29b of the lugs 24a, 24b above the joined lug stacks 26a, 26b are trimmed so that all lugs terminate in substantially the same location. Alternatively, these portions can be left in place and trimmed or folded after the welding process is complete. In one embodiment, the excess portions are deflected, as discussed further herein.

[0076] In the fourth stage, reference Figure 6D , the connection assembly 50 is introduced, and the lug stacks 26a, 26b are placed against the respective surfaces 30a, 30b.

[0077] In the fifth stage, reference Figure 6E , a welding device is applied to weld the tab stacks 26a and 26b to their respective surfaces. The connection assembly 50 can be moved upwardly away from the battery cell stack 22 (z direction) to keep the tab stacks secure while performing the welding.

[0078] In one embodiment, the welding device is an ultrasonic welder comprising opposing sonotrodes 54. Each sonotrode 54 is applied to hold the tab stack 26 in position against the welding surfaces 30a, 30b. The sonotrodes 54 can be activated together as a single welding process. As discussed herein, the welding surfaces 30a, 30b can have a textured pattern integrated with the surface.

[0079] In the sixth stage, reference Figure 6F , remove the sonotrode 54 . The connection assembly 50 can be moved toward the battery cell stack 22 to provide strain relief to the portion of the tab 24 between the tab stacks 26 a , 26 b and the battery cell stack 22 .

[0080] Additional steps or stages may be performed to complete assembly of the battery cell 10 , such as mounting weld electrodes in a housing (eg, a pouch or rigid housing) with a separator layer, quality inspection, electrolyte filling, housing sealing, etc.

[0081] The battery cell 10 may be mounted in a battery assembly such as a battery pack or a battery module. For example, the battery cell 10 is mounted in a battery module together with other cells, and the battery module is mounted in an electric vehicle or a hybrid vehicle.

[0082] It should be noted that the manufacturing system 40, connection assembly 50, and method 80 are not intended to limit the embodiments to any particular manufacturing process.Any suitable manufacturing system or process that includes some form of battery tab formation and electrical connection may be used.

[0083] As discussed, the tab stacks 26a and 26b may be welded to their respective surfaces 30a and 30b by ultrasonic welding, but are not limited thereto, as any suitable welding or joining technique may be used. Examples of other suitable joining techniques include laser welding, arc welding, mechanical joining, adhesives, and combinations thereof. In one embodiment, the tab stacks 26a and 26b are joined via an ultrasonic and / or laser welding process.

[0084] refer to Figure 7 and 8 For example, tab stacks 26a and 26b are connected to surfaces 30a and 30b by a laser welding process. Laser welding is performed by applying laser beam 70a to tab stack 26a and surface 30a, and simultaneously applying laser beam 70b to tab stack 26b and surface 30b (or applying laser beam 70b at another time, if desired).

[0085] The lug stack can be directly welded, such as Figure 7 Alternatively, as Figure 8As shown, prior to welding, conductive sheets or plates 72 (shown as plates 72a and 72b) are applied to each lug stack opposite the welding surface. For example, plate 72a is applied to the outermost layer of lug stack 26a, and plate 72b is applied to the outermost layer of lug stack 26b, thereby sandwiching each lug stack. Each plate 72a, 72b is welded to its corresponding lug stack.

[0086] In another example, Figure 9 As shown, the lug stacks 26a and 26b are connected to the surfaces 30a and 30b by a combined laser and ultrasonic welding process. In this process, each lug stack 26a, 26b is first welded via ultrasonic welding (independent of the weld plate 28), thereby producing a welded lug stack 27 (shown as welded lug stacks 27a and 27b). The welded lug stacks 27a and 27b are then welded to the respective surfaces 30a and 30b of the weld plate 28 by laser welding.

[0087] The methods described herein may include various methods for collecting and / or removing excess tab portions or excess foil. Excess foil is defined as that portion of the tab above the welded tab stack. For example, the excess foil may be trimmed as described above, or collected so as not to interfere with the operation of the completed battery cell.

[0088] Figure 10 An embodiment of the connection assembly 50 is shown that includes a diversion feature in the form of one or more recesses 74 formed in the insulating insert 62. Each recess may be formed exclusively in the insulating insert 62, in portions of both the insulating insert 62 and the cover plate 60, or otherwise in any suitable location or portion of the connection assembly 50.

[0089] For example, recess 74a is formed in insert 62 adjacent to welding plate 28, causing excess portion 29a above lug stack 26a to be deflected along a curved path extending generally perpendicular to lug stack 26a. Recess 74b is similarly formed in insert 62 adjacent to welding plate 28, causing excess portion 29b above lug stack 26b to be deflected along a curved path. In this manner, excess portions 29a, 29b are deflected without introducing any folds or creases, and without interfering with subsequent welding of flat lug stacks 26a and 26b.

[0090] Figure 11An example is shown in which the connection assembly 50 includes a deflection device 76 that deflects excess material without causing the portion of the lug stack being welded to fold or bend. In this example, the deflection device 76 is a U-shaped clamp 76 that can be used to deflect excess material above the weld without causing trimming or creasing of the welded portion.

[0091] Each clamp 76a, 76b can have any overall width (in the y-axis direction) corresponding to the width of the tab stacks 26a, 26b and a length (in the z-axis direction) equal to or similar to the length of the connecting members 52a, 52b. Each clamp 76a, 76b allows excess foil to deflect, forming a 180-degree U-shaped bend. Each clamp 76a, 76b can be held in place during welding (e.g., via an ultrasonic generator and / or other suitable device).

[0092] Each clamp 76a, 76b can be held in place during the welding process so that at least a portion of the clamp 76a, 76b forms part of the weld. For example, the lug stack 26a and the clamp 76a are held against the surface 30a (with a portion of the clamp 76a sandwiched between the stack 26a and the surface 30a) and welded together. The weld fuses the two sides of the clamp, the lug stack, and the weld plate surface together.

[0093] Figures 12A-12F Aspects of a method of manufacturing a battery cell are shown. Figures 12A-12F The method can be used as Figures 6A-6F For example, you can perform a link Figures 12A-12F The steps described in this article can be used to replace the trimming steps discussed in this article.

[0094] The method (or portions thereof) may be performed by any suitable processing device or devices, such as, but not limited to, one or more controllers of manufacturing system 40 (e.g., controller 49 coupled to welding station 48) and / or connection system 50.

[0095] The method includes a plurality of steps or phases. The method is not limited to the number or order of the steps therein, as some steps may be performed in a different order than described below, or fewer than all steps may be performed.

[0096] In the first stage, reference Figure 12A , some portions of the anode tabs 24 are collected into a tab stack 26. For example, the anode tabs 24 are divided into two groups of tabs 24a and 24b. Although only one group of tabs 24a and the associated tab stack 26a are shown, it should be understood that the other group of tabs 24b and the tab stack 26b are similarly treated.

[0097] In the second stage, reference Figure 12B The lugs 24a are provided with a connecting device such as a clamp 70 and are compressed to form a connected or compressed lug stack 26a. The portion of the lug 24a above the clamp 70 is referred to as the excess portion 29a.

[0098] In the third stage, reference Figure 12C A first force applicator 80 (eg, a laterally extendable plunger 80 ) is applied to the excess portion 29 a so that the excess portion 29 a extends laterally and forms an angle of approximately 90 degrees relative to the wafer stack 26 a .

[0099] In the fourth stage, reference Figure 12D , a second force applicator 82 (e.g., a vertically extendable plunger 82) is applied to the excess foil portion 29a to vertically bend a portion of the excess portion 29a. In this way, a 180-degree bend is formed, and the excess portion 29a forms a U-shape with the tab stack 26a, as shown in FIG. Figure 12E As a result, the excess portion can be deflected in a gradual manner without introducing any creases or folds.

[0100] In the fifth stage, reference Figure 12F The clamp 76a is slid over or otherwise disposed around the lug stack 26a and the excess portion 29a. The clamp 76a is used to hold the lug stack 26a and the excess portion 29a in a U-shape.

[0101] The term "a" or "an" does not indicate a limitation of quantity, but rather indicates the presence of at least one of the referenced item. Unless the context clearly indicates otherwise, the term "or" means "and / or". References to "aspects" throughout this specification mean that a particular element (e.g., a feature, structure, step, or characteristic) described in connection 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 elements described may be combined in any suitable manner in each aspect.

[0102] 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.

[0103] Unless otherwise indicated herein, all test standards are the most current standards in effect as of the filing date of this application, or, if priority is claimed, the filing date of the earliest priority application in which the test standards appear.

[0104] 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.

[0105] Although the above disclosure has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope thereof. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the basic scope of the present disclosure. Therefore, it is intended that the present disclosure is not limited to the particular embodiments disclosed, but is intended to include all embodiments falling within its scope.

Claims

1. A system for electrically connecting tabs of a battery cell, comprising: a conductive welding plate configured to be disposed within a housing of the battery cell and electrically connected to a tab stack formed by a plurality of tabs extending from electrode layers of a battery cell stack, the welding plate having a welding surface at least partially oriented in a vertical direction parallel to surfaces of the electrode layers forming the electrode stack; as well as A welding device is configured to weld the lug stack to the welding surface and form at least a portion of a connector, wherein the lug stack is welded while maintaining the lug stack in a planar configuration and an undeformed state.

2. The system according to claim 1, wherein: The undeformed state is a state in which the tab stack is not folded before welding and is not subjected to bending force during the welding.

3. The system according to claim 1, wherein: The welding device is configured to perform a welding method including at least one of ultrasonic welding and laser welding, the welding device includes at least one of a laser welding device and an ultrasonic welding device, the ultrasonic welding device includes a sonotrode configured to engage the tab stack and the welding surface.

4. The system according to claim 3, wherein: The welding surface includes a textured pattern to facilitate welding the lug stack to the welding plate.

5. The system according to claim 1, wherein: The tab stack includes a first tab stack and a second tab stack formed by the plurality of tabs, and the welding surface includes a pair of opposite welding surfaces, each of the opposite welding surfaces being configured for welding one of the first tab stack and the second tab stack to the welding plate.

6. The system according to claim 1 further includes an actuator configured to move the welding plate in the vertical direction, and the actuator is controllable to move the welding plate in the vertical direction toward the battery cell stack after welding to relieve stress on some portions of the plurality of tabs between the battery cell stack and the tab stack.

7. The system according to claim 1, wherein: The housing is a rigid housing.

8. The system of claim 1, further comprising a joining device configured to engage the plurality of lugs and join the plurality of lugs together in the planar configuration to form the lug stack.

9. A method for electrically connecting tabs of a battery cell, comprising: obtaining a battery cell stack configured to be disposed in a housing to form the battery cell, wherein a plurality of tabs extend from an electrode layer of the battery cell stack; forming a tab stack from a portion of the plurality of tabs and disposing the tab stack against a welding surface of a welding plate configured to be disposed within the housing, the welding surface being at least partially oriented in a vertical direction parallel to surfaces of electrode layers forming the electrode stack; and The lug stack is welded to the welding surface by a welding device to form at least a portion of a connector, wherein the lug stack is welded while being maintained in a planar configuration and an undeformed state.

10. The method according to claim 9, wherein: The undeformed state is a state in which the tab stack is not folded before welding and is not subjected to bending force during the welding.

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