Battery cell current collector tab with feature to facilitate electrical connection

Abstract

A battery cell includes a case enclosing an anode and a cathode, and an electrode assembly disposed in the case, the electrode assembly including a plurality of electrode layers, each of the plurality of electrode layers having a respective tab configured to electrically connect the plurality of electrode layers to each other. The first electrode layer includes a first tab offset from another tab of another electrode layer.

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 vehicles and hybrid vehicles). For example, electric vehicle and hybrid vehicle battery systems include battery modules having multiple battery cells. Battery cells can be pouch cells, prismatic cells, or other types of batteries, 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 battery cell includes a housing enclosing an anode and a cathode, and an electrode assembly disposed in the housing, the electrode assembly including a plurality of electrode layers, each of the plurality of electrode layers having a respective tab, the tabs being configured to electrically connect the plurality of electrode layers to each other. A first electrode layer includes a first tab, the first tab being offset from another tab of another electrode layer.

[0004] In addition to one or more features described herein, the electrode assembly includes at least one of a plurality of anode layers and a plurality of cathode layers. Each of the plurality of anode layers has a respective anode tab configured to electrically connect the plurality of anode layers to one another, wherein a first anode layer includes a first anode tab that is offset from another anode tab of another anode layer. Each of the plurality of cathode layers has a respective cathode tab configured to electrically connect the plurality of cathode layers to one another, wherein a first cathode layer includes a first cathode tab that is offset from another cathode tab of another cathode layer.

[0005] In addition to one or more of the features described herein, the first electrode layer is a first subset of multiple electrode layers, the first subset having a first set of tabs, and the other electrode layer is a second subset of multiple electrode layers, the second subset having a second set of tabs, wherein the first set of tabs are offset from the second set of tabs.

[0006] In addition to one or more features described herein, the first set of tabs and the second set of tabs each define an individual stack of tabs, each individual stack of tabs being configured to be welded together by a single weld.

[0007] In addition to one or more features described herein, the respective tabs of the plurality of electrode layers are arranged in an alternating pattern.

[0008] In addition to one or more features described herein, the first tab overlaps the other tab.

[0009] In addition to one or more features described herein, the first tab and the further tab are part of a group of tabs, each of the group of tabs being successively offset to form a continuous tab.

[0010] In addition to one or more features described herein, the first tab is offset by forming the first tab so that the first tab is located a first distance from one side of the first tab and the other tab is located a second distance from one side of the other tab, the first distance being different from the second distance.

[0011] In addition to one or more features described herein, the battery cell is configured to be mounted in a battery assembly having a plurality of battery cells.

[0012] In addition to one or more features described herein, the battery assembly is configured to be disposed in a vehicle to supply electrical power for propelling the vehicle.

[0013] In another exemplary embodiment, a method of manufacturing a battery cell includes obtaining an electrode material, and creating a plurality of electrode layers from the electrode material, wherein the creating includes forming respective tabs for each electrode layer, wherein a first electrode layer is formed with a first tab, the first tab being offset from another tab of another electrode layer. The method also includes electrically connecting the plurality of electrode layers by welding the respective tabs together, and installing the connected electrode layers in a housing.

[0014] In addition to one or more of the features described herein, the first electrode layer is a first subset of multiple electrode layers, the first subset having a first set of tabs, and the other electrode layer is a second subset of multiple electrode layers, the second subset having a second set of tabs, wherein the respective tabs are formed so that the first set of tabs are offset from the second set of tabs.

[0015] In addition to one or more of the features described herein, electrically connecting multiple electrode layers includes stacking a first group of tabs as a first tab stack, stacking a second group of tabs as a second tab stack, welding the first tab stack through a single weld, and welding the second tab stack as another single weld.

[0016] In addition to one or more features described herein, the first tab overlaps the other tab.

[0017] In addition to one or more features described herein, the first tab and the further tab are part of a group of tabs, each of the group of tabs being successively offset to form a continuous tab.

[0018] In addition to one or more features described herein, the first tab is offset by forming the first tab so that the first tab is located a first distance from one side of the first tab and the other tab is located a second distance from one side of the other tab, the first distance being different from the second distance.

[0019] In addition to one or more features described herein, forming the respective tabs includes cutting a series of notches in the electrode material, the series of notches cut to define the respective offset distances.

[0020] In addition to one or more features described herein, cutting the series of notches is performed by a translatable notch die.

[0021] In yet another exemplary embodiment, a vehicle system includes a battery assembly, the battery assembly including a battery cell, the battery cell including a housing and an electrode assembly disposed in the housing, the electrode assembly including a plurality of electrode layers, each of the plurality of electrode layers having a respective tab, the tabs being configured to electrically connect the plurality of electrode layers to each other. A first electrode layer includes a first tab, the first tab being offset from another tab of another electrode layer.

[0022] In addition to one or more features described herein, the electrode assembly includes at least one of a plurality of anode layers and a plurality of cathode layers. Each of the plurality of anode layers has a respective anode tab configured to electrically connect the plurality of anode layers to one another, wherein a first anode layer includes a first anode tab that is offset from another anode tab of another anode layer. Each of the plurality of cathode layers has a respective cathode tab configured to electrically connect the plurality of cathode layers to one another, wherein a first cathode layer includes a first cathode tab that is offset from another cathode tab of another cathode layer.

[0023] The above features and advantages and other features and advantages of the present disclosure are 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, from the following detailed description, which refers to the accompanying drawings, in which:

[0025] Figure 1 An example of a prismatic battery cell is depicted;

[0026] Figure 2 depicts two electrode layers with offset tabs according to an exemplary embodiment;

[0027] Figure 3 is a side view of an electrode assembly according to an exemplary embodiment, the electrode assembly including electrode layers electrically connected by a set of tabs in an offset configuration;

[0028] Figure 4 yes Figure 3 A perspective view of an electrode assembly;

[0029] Figure 5 depicts a portion of a battery cell according to an exemplary embodiment;

[0030] Figure 6 depicts a portion of a battery cell according to an exemplary embodiment;

[0031] Figure 7 depicts a set of electrodes having overlapping tabs according to an exemplary embodiment;

[0032] Figure 8 depicts a system for manufacturing a battery cell according to an exemplary embodiment;

[0033] Fig. 9 is a flow chart of a method of manufacturing a battery cell according to an exemplary embodiment;

[0034] Fig. 10A and 10B Depicts components of a manufacturing system according to an exemplary embodiment, including a mechanical mold for forming electrode tabs, and aspects of a method of manufacturing a battery cell; and

[0035] Fig.11 A motor vehicle including a battery system is depicted according to an exemplary embodiment. DETAILED DESCRIPTION

[0036] 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.

[0037] 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 battery cells include electrodes disposed in a housing as multiple anode layers and multiple cathode layers. The layers may be sheets or foils made of conductive material, and each layer includes a connection portion that allows the layers to be stacked and welded. The connection portion may be referred to as a "connection tab" or simply a "tab," for example, a group of anode layers are electrically connected by welding their respective anode tabs together as a "welded stack." The cathode layers are similarly connected by welding the cathode tabs.

[0038] To facilitate effective electrical connection and proper welding, in an embodiment, the electrode layers are formed with respective tabs in an offset configuration, wherein at least one tab is offset from at least one other tab when the electrode layers are stacked as part of a battery cell. For example, a set of anode layers (anodes) is configured such that a subset of tabs forms a first tab stack, and the first tab stack is offset or separated from another subset of tabs forming a second tab stack, allowing the tab stacks to be welded individually and reducing the width of the weld. The offset configuration can result in tabs that are completely separated, overlapping, or a combination thereof. Embodiments also include methods of manufacturing battery cells having tabs in an offset configuration.

[0039] The embodiments described herein present many advantages and technical effects. Embodiments provide an improved manufacturing process that facilitates proper attachment and electrical connection of electrode tabs. For example, by providing offset tabs as described herein, the number of layers in each weld stack can be reduced, which ensures high-quality welds. In this way, any number of electrode layers can be connected while maintaining a sufficiently short weld path to avoid a loss in weld quality that would otherwise occur as the number of tabs welded together increases.

[0040] Figure 1 An example of a battery cell 10 is depicted. The battery cell includes a housing 12, which may be a rigid housing (e.g., a drawn aluminum housing) that is sealed to enclose a plurality of electrodes. Housing 12 may be made of any suitable 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, embodiments may be applicable to pouch-type batteries and other types of batteries.

[0041] The battery cell 10 includes a plurality of negative electrode or anode layers 14 and a plurality of positive electrode or cathode layers 16. The anode and cathode are made of a selected conductive material and are configured as a sheet or foil. A separator 18 made of an electrically insulating material (e.g., a polymer or ceramic) is disposed between each anode 14 and an adjacent cathode 16. An active material 20 (such as graphite or a material including lithium) is disposed in the housing 12 between the various layers.

[0042] It should be noted that the number of electrodes is not limited to Figure 1 The battery cell may have any number of anode layers 14 and any number of cathode layers 16. For example, a battery cell may have hundreds of individual foil layers forming the electrodes.

[0043] like Figure 1 As shown, each anode layer 14 includes a portion 22 that extends away from the interior of the battery 10 and allows each anode layer 14 to be electrically connected to another anode layer 14. Portions 22 are also referred to as tabs 22 or connecting tabs 22. Although not shown, cathode layers 16 similarly include tabs so that cathode layers 16 can be connected.

[0044] The tabs 22 (or a subset thereof) are stacked together as a tab stack 24. The tab stack 24 welds the foils or tabs together by, for example, primary ultrasonic welding. The weld may be a solid state weld joint formed by ultrasonic welding or a fusion weld joint formed by laser welding, although other metal-to-metal joining processes may also be used.

[0045] Tab stack 24 may be attached to a conductive connector 26. Connector 26 forms a negative terminal. Cathode layer 16 may similarly be welded to a positive terminal (not shown) that extends outside of casing 12.

[0046] As the number of tabs 22 increases, the quality of the weld may deteriorate, which may result in faulty electrical connections, suboptimal operation, and damage to the cell 10 and / or other components connected to the cell 10 .

[0047] In an embodiment, at least one tab 22 is positioned relative to its respective anode layer 14 such that at least one tab 22 is offset compared to at least one other tab 22. A first tab is "offset" from a second tab when the first and second tabs are not completely aligned when their respective electrode layers are stacked / aligned. For example, the two tabs may be offset so that they are completely separated, or offset so that they overlap.

[0048] In an embodiment, the tabs 22 are positioned so that they define at least two separate foil stacks or tab stacks. In another embodiment, the tabs are positioned so that at least a subset of the tabs overlap successively to create a relatively thin elongated stack ("overlapping stack").

[0049] Figure 2-4 An embodiment is depicted that can be used to create multiple tab stacks and / or at least one offset stack or tab of an offset configuration. For purposes of illustration, this embodiment is described in conjunction with anode layer 14, but is not limited thereto (eg, a similar offset configuration may be provided for cathode layer 16).

[0050] In this embodiment, the tabs 22 are configured such that when the anode layer 14 is aligned, the tabs 22 define at least two separate tab stacks. Figure 2 , a first subset of tabs 22 (denoted as tabs 22a) is formed on a first subset of anode layers 14 (denoted as anode layers 14a).

[0051] like Figure 2 As shown, the anode layer 14a has a tab 22a formed at the end 30a of the anode layer 14a. The tab 22a is offset from the side 32a of the anode layer 14a by a selected offset length L1 in a direction (x direction) along the end 30a.

[0052] Tab 22b is formed at end 30b of anode layer 14b. Tab 22b is offset from side 32b of anode layer 14b in the x-direction by a selected offset length L2 such that L1 and L2 are different lengths. These lengths may be selected such that tab 22a is completely separated from tab 22b (relative to the x-direction) or such that tab 22a overlaps tab 22b in the x-direction.

[0053] For example, Figure 3 As shown, tab 22a is offset from tab 22b such that tab 22a is adjacent to tab 22b. Lengths L1 and L2 may be selected such that a gap 34 is provided for tolerance.

[0054] Figure 4 The anode layer 14 with offset tabs is shown when the tabs 22 have been stacked and welded together. As shown, the stack of tabs 22a is welded to the welding plate 36. The stack of tabs 22b is also welded to the welding plate 36. It should be noted that the two stacks can be welded in a single welding pass.

[0055] Thus, instead of a single foil stack or tab stack, tabs 22a and 22b define two separate stacks. The width of the weld path is reduced by half because each stack is half the width of a typical single stack, resulting in a higher quality weld.

[0056] The various tabs may be offset to define any desired pattern. Figure 5 and Figure 6 An example of such a pattern is shown, which allows for collection of tabs at various weld locations. A portion of a battery cell 10 is shown, including layers of anode 14 and cathode 16 (with a separator layer, not shown).

[0057] The anode layers 14 are connected to each other via tabs 22, which are welded to an anode welding plate 40. The cathode layers 16 are connected to each other via tabs 44, which are welded to a cathode welding plate 42. The anode welding plate 40 and the cathode welding plate 42 may form respective anode and cathode terminals, or may be connected to other components to form terminals.

[0058] Figure 5 Examples are shown in which the offset pattern is selected so that groups of anode layers 14 or cathode layers 16 define individual stacks (with the tabs in each stack being at least substantially aligned). Figure 6 An example is shown in which the offset pattern is selected such that adjacent anode tabs 22 and adjacent cathode tabs 44 are offset and define an alternating pattern.

[0059] As described above, the anode layer 14 may have one or more overlapping anode tabs 22, and the cathode layer 16 may have one or more overlapping cathode tabs 44. For example, some or all of the anode tabs 22 may overlap.

[0060] Figure 7An example of an overlapping tab configuration is shown, where a set of n tabs 22 are successively overlapped. In this example, seven anode layers are shown, represented as anodes 14-1, 14-2, 14-3, 14-4, 14-5, 14-6 and 14-n. Each layer includes a corresponding tab, represented as tabs 22-1, 22-2, 22-3, 22-4, 22-5, 22-6 and 22-n. The configuration can have any number of anodes and respective tabs.

[0061] The overlapping pattern can be achieved by cutting or otherwise forming the tabs so that each tab is formed with a successively longer offset length. As shown, when the anode layers are assembled into an anode stack 46, the tabs 22-1, 22-2, 22-3, 22-4, 22-5, 22-6 and 22-n form an overlapping pattern, which results in a relatively thin tab for the entire anode stack 46.

[0062] Figure 8 An example of a manufacturing system 50 for manufacturing battery cells is depicted. The manufacturing system 50 includes various manufacturing stations that may be controlled or operated by a computer system, a human operator, or a combination thereof, such as a controller 51. The controller 51 may include processing circuitry that may include an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) that executes one or more software or firmware programs and memory, combinational logic circuits, and / or other suitable components that provide the described functionality. The controller 51 may include a non-transitory computer-readable medium storing instructions that, when processed by one or more processors of the controller 51, implement aspects of the methods described herein.

[0063] As used herein, a "station" refers to any number, combination, and arrangement of equipment, and is not intended to limit manufacturing system 50 to any particular machine or combination of machines.

[0064] The manufacturing system includes, for example, an active material processing station 52 for preparing active material to be applied to the electrode. The system 50 may also include a coating station 54 for coating the electrode with the active material.

[0065] The manufacturing system 52 also includes an electrode cutting station 56, which can be used to form tabs along the electrode sheet so that the tabs form an offset pattern or configuration as described herein. The tabs can be formed in any suitable manner, such as by laser cutting, stamping, punching, etc. In some cases, the tabs can be formed by attaching the tabs to the electrode sheet at the desired location. The cutting station 56 can include one or more cutting dies.

[0066] The system 50 may include other stations for performing subsequent processing to complete the battery cells. Examples include a stacking station 58, a welding station 60, and an assembly station 62 (eg, for battery packaging, sealing, electrolyte filling, etc.).

[0067] The manufacturing system 50 may include additional stations for manufacturing battery assemblies, such as battery packs and / or modules. For example, battery cells may be installed 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 (e.g., an electric vehicle or a hybrid vehicle) as part of a battery pack.

[0068] Fig. 9 An embodiment of a method 70 of manufacturing a battery cell is shown. The method 70 (or portions thereof) may be performed by any suitable one or more processing devices, such as the controller 51 of the manufacturing system 50, but is not limited thereto.

[0069] Method 70 includes a number of steps or stages represented by blocks 71-75. Method 70 is not limited to the number or order of steps therein, as some steps represented by blocks 71-75 may be performed in a different order than described below, or fewer than all of the steps may be performed.

[0070] At block 71, an electrode is created or obtained, 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.

[0071] At box 72, the anode sheet is cut, trimmed or otherwise processed to create a series of anode tabs. Similarly, the cathode sheet is processed to create a series of cathode tabs. The tabs are positioned so that when the sheets are wrapped and / or stacked to construct a battery cell, they will have a desired offset pattern or configuration (as described herein).

[0072] For example, Fig. 10A and 10B As shown, a sheet 80 of coated electrode material (anode or cathode material) is fed via a conveyor belt (or other suitable device) to a cutting station 56. A mechanical die 82 (referred to as a notch die) is disposed above the sheet 80 and can translate in a vertical direction (represented by arrow V) and a horizontal direction (represented by arrow H). Fig. 10A A front view of the notch mold 82 is shown, and Fig. 10B A bottom view of the notch mold 82 is shown.

[0073] As the sheet 80 moves beneath the notch die 82, the notch die 82 moves horizontally to a desired position to cut notches in the sheet 80 at desired locations to define tabs at desired offset lengths. Fig. 10ATwo examples of the position of the notch mold 82 are shown, and Fig. 10B The corresponding position 84 of the notch formed at each location is shown.

[0074] The anode and cathode sheets and their respective tabs are stacked or otherwise assembled with the separator layer at box 73. As described above, the tabs of the anode layer are electrically connected via welding, and the tabs of the cathode layer are similarly connected.

[0075] At box 74 , additional steps are performed to complete assembly of the battery cell, such as mounting welded electrodes in a housing (eg, a prismatic housing) with a separator layer, quality inspection, electrolyte filling, housing sealing, and the like.

[0076] At block 75, the battery cell may be installed in a battery assembly such as a battery pack or a battery module. For example, the battery cell is installed in a battery module together with other cells, and the battery module is installed in an electric vehicle or a hybrid vehicle.

[0077] Note that the manufacturing system 50 and method 70 are not intended to limit the embodiments to any particular manufacturing process.Any suitable manufacturing system or process that includes some form of single-body tab creation and electrical connection may be used.

[0078] As described herein, a battery cell including an offset tab as described herein may be part of a vehicle battery system. Fig.11 An embodiment of a motor vehicle 100 is shown that includes a vehicle body 102. The vehicle 100 may be an internal combustion engine vehicle, an electric vehicle (EV), or a hybrid electric vehicle (HEV). In an example, the vehicle 100 is a hybrid or electric vehicle having an electric motor 104. A battery system 106 is electrically connected to the electric motor 104 and / or other components, such as vehicle electronics. The battery system 106 includes one or more modules 108 that form part of a battery pack (not shown), wherein each module 108 includes a plurality of battery cells 10.

[0079] The terms "a" and "an" do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. Unless the context clearly indicates otherwise, the terms "or" mean "and / or". References to "aspects" 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 the various aspects.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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 its scope. In addition, many modifications may be made to adapt specific circumstances or materials to the teachings of the disclosure without departing from the basic 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 housing enclosing the anode and the cathode; as well as An electrode assembly is disposed in the shell, the electrode assembly comprising a plurality of electrode layers, each of the plurality of electrode layers having respective tabs configured to electrically connect the plurality of electrode layers to each other, wherein a first electrode layer comprises a first tab offset from another tab of another electrode layer.

2. The battery cell according to claim 1, wherein the electrode assembly comprises at least one of the following: a plurality of anode layers, each of the plurality of anode layers having a respective anode tab configured to electrically connect the plurality of anode layers to each other, wherein a first anode layer comprising a first anode tab offset from another anode tab of another anode layer; as well as A plurality of cathode layers, each of the plurality of cathode layers having a respective cathode tab configured to electrically connect the plurality of cathode layers to one another, wherein a first cathode layer includes a first cathode tab offset from another cathode tab of another cathode layer.

3. The battery cell according to claim 1, wherein: The first electrode layer is a first subset of the plurality of electrode layers, the first subset having a first set of tabs, and the another electrode layer is a second subset of the plurality of electrode layers, the second subset having a second set of tabs, wherein the first set of tabs is offset from the second set of tabs.

4. The battery cell according to claim 3, wherein: The first set of tabs and the second set of tabs each define an individual stack of tabs, each individual stack of tabs being configured to be welded together by a single weld.

5. The battery cell according to claim 1, wherein: The respective tabs of the plurality of electrode layers are arranged in an alternating pattern. The battery cell according to claim 1 , wherein the first tab overlaps the other tab.

7. The battery cell according to claim 6, wherein: The first tab and the further tab are part of a group of tabs, each of which is successively offset to form a continuous tab.

8. The battery cell according to claim 1, wherein: The first tab is offset by forming the first tab so that the first tab is located at a first distance from one side of the first tab and the other tab is located at a second distance from one side of the other tab, the first distance being different from the second distance.

9. A method for manufacturing a battery cell, comprising: Obtaining electrode materials; creating a plurality of electrode layers from the electrode material, wherein the creating includes forming respective tabs for each electrode layer, wherein a first electrode layer is formed with a first tab that is offset from another tab of another electrode layer; electrically connecting the plurality of electrode layers by welding the respective tabs together; and The connected electrode layers are mounted in a housing.

10. The method according to claim 9, wherein: The first electrode layer is a first subset of the plurality of electrode layers, the first subset having a first set of tabs, and the another electrode layer is a second subset of the plurality of electrode layers, the second subset having a second set of tabs, wherein the respective tabs are formed such that the first set of tabs are offset from the second set of tabs.

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