Cell with Tabless Structure Electrode

Abstract

An energy storage device cell having at least one electrode that is tabless-less and a method for manufacturing the same are described. The cell includes a first substrate having a first coating disposed thereon, and a second portion of the first substrate at a proximal end along the width of the first substrate comprises an electrical conductor. An inner separator is disposed on the first substrate. A second substrate is disposed on the inner separator. The second substrate has a second coating disposed thereon. The first substrate, inner separator, and second substrate are continuous, and the first substrate, inner separator, and second substrate are wound around a central axis.

Description

[Technical field]

[0001] [Incorporation by reference of priority application] This application claims priority to U.S. Provisional Patent Application No. 62 / 755,685, filed November 5, 2018, which is incorporated by reference in its entirety. background

[0002] The present disclosure relates to cells for energy storage devices. [Background technology]

[0003] Many types of battery cells are currently used as energy sources in electric vehicles and energy storage applications. Current cells use a jelly-roll design in which the cathode, anode, and separator are wound together and have cathode and anode tabs for connection to the positive and negative terminals of the cell can. The path of current naturally travels through these tabs to a connector on the outside of the battery cell. However, if the current must flow along the cathode or anode to the tabs and out of the cell, ohmic resistance increases with distance. Furthermore, the tabs are additional components, which increases cost and presents manufacturing challenges. Summary of the Invention [Means for solving the problem]

[0004] In order to summarize the present invention and the advantages achieved over the prior art, certain objects and advantages of the present invention are described herein. Not all such objects or advantages may be achieved in any particular embodiment of the present invention. Thus, for example, a person skilled in the art will recognize that the present invention may be embodied or carried out in a manner that achieves or optimizes one or more advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.

[0005] In one embodiment, a cell of an energy storage device is described, the cell comprising a first substrate having a first coating, where a second portion of the first substrate at a proximal end along a width of the first substrate comprises an electrical conductor, a second substrate having a second coating, and an inner separator disposed between the first substrate and the second substrate, the first substrate, the inner separator, and the second substrate being wound around a central axis to form the cell.

[0006] In some embodiments, the electrical conductor consists essentially of a first substrate. In some embodiments, the first substrate is a current collector. In some embodiments, when wound, the first substrate is aligned closest to the central axis. In some embodiments, when wound, the second substrate is aligned closest to the central axis.

[0007] In some embodiments, a first portion of the first substrate positioned partway along the width of the first substrate is coated with an electrically insulating material. In some embodiments, the second portion is positioned adjacent to the first portion. In some embodiments, the second substrate further comprises a conductive tab. In some embodiments, the conductive tab is positioned partway along the length of the second substrate and extends across a mid-plane of the second substrate. In some embodiments, the first substrate forms one of the anode and the cathode, and the second substrate forms the other of the anode and the cathode.

[0008] In another aspect, an energy storage device is described that includes an energy storage device cell and a can with a first end and a second end, the first end including a first cap with a contact surface.

[0009] In some embodiments, the electrical conductor is in electrical contact with the contact surface. In some embodiments, the first end comprises a bottom wall. In some embodiments, the first and second ends are each open ends. In some embodiments, the first end of the can is configured to receive a first cap. In some embodiments, the second end of the can is configured to receive a second cap. In some embodiments, the first cap comprises at least one of nickel (Ni) and a Ni-based alloy. In some embodiments, the contact surface of the first cap comprises a spiral-shaped groove.

[0010] In another aspect, a method for forming a cell is described that includes providing a first substrate having a first coating, where a second portion of the first substrate at a proximal end along a width of the first substrate comprises an electrical conductor, disposing an inner separator over the first substrate, providing a second substrate having a second coating, disposing the second substrate over the inner separator, and winding the first substrate, the inner separator, and the second substrate disposed on top of each other about a central axis to form a cell.

[0011] In some embodiments, the location of the first substrate is closest to the central axis. In some embodiments, the location of the second substrate is closest to the central axis. In some embodiments, the first substrate, the inner separator, and the second substrate are disposed on top of each other in a sequential manner.

[0012] In some embodiments, the method further includes coating a first portion of the first substrate with an electrically insulating material, the first portion being positioned partway along a width of the first substrate. In some embodiments, the second portion is positioned adjacent to the first portion. In some embodiments, the method further includes extending a portion of the second substrate across a midplane of the second substrate to form a conductive tab partway along a length of the second substrate.

[0013] In another aspect, a method of forming an energy storage device is described, the method includes forming a cell and placing the cell into a can having a first end and a second end, the first end including a first cap having a contact surface.

[0014] In some embodiments, the method further includes electrically connecting the electrical conductor with the contact surface.

[0015] All of these embodiments are intended to be within the scope of the invention disclosed herein. These and other embodiments of the invention will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiments, which description refers to the accompanying drawings, but the invention is not limited to any specific preferred embodiment disclosed. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2 is a perspective view of a cell showing a first substrate, an inner separator, a second substrate, and an outer separator according to certain embodiments of the present disclosure.

[0017] [Diagram 2] 2 illustrates a layout of the cell of FIG. 1 according to certain embodiments of the present disclosure.

[0018] [Figure 3A] 1 illustrates an exemplary setup that can be used to coat a first substrate according to certain embodiments of the present disclosure.

[0019] [Figure 3B] 1 illustrates an exemplary setup that can be used to coat a first substrate according to certain embodiments of the present disclosure.

[0020] [Figure 4] 1 illustrates a first cap having a contact surface that can be used to make an electrical connection with a conductive portion of a first substrate, according to certain embodiments of the present disclosure.

[0021] [Diagram 5] 1 illustrates a can shown enclosing a first substrate, an inner separator, a second substrate, and an outer separator of a cell with a first cap, according to certain embodiments of the present disclosure.

[0022] [Figure 6A] FIG. 2 is a cross-sectional view of the bottom of an energy storage device showing a contact surface of a first cap connected to a conductive portion of a first substrate according to certain embodiments of the present disclosure.

[0023] [Figure 6B] FIG. 2 is a cross-sectional view of the bottom of an energy storage device showing the contact surface of the can connected to a conductive portion of the first substrate according to certain embodiments of the present disclosure.

[0024] [Figure 6C] 1 illustrates a layout of a first substrate showing multiple conductive portions evenly and intermittently spaced apart from one another, according to certain embodiments of the present disclosure.

[0025] [Figure 6D] 1 illustrates a layout of a first substrate showing multiple conductive portions having gradually increasing widths and gradually increasing distances from one another, according to certain embodiments of the present disclosure.

[0026] [Figure 6E] FIG. 2 is a bottom view of a cell showing the conductive portion of the rolled first substrate according to certain embodiments of the present disclosure.

[0027] [Figure 7] 1 illustrates a method for manufacturing a cell according to certain embodiments of the present disclosure.

[0028] [Figure 8] FIG. 2 is a diagram of a cell showing a first substrate, an inner separator, a second substrate, and an outer separator according to certain embodiments of the present disclosure.

[0029] [Figure 9] 9 illustrates a layout of the cell of FIG. 8 according to certain embodiments of the present disclosure.

[0030] [Figure 10A] 13 illustrates an alternative configuration of a first cap having a contact surface according to certain embodiments of the present disclosure. [Figure 10B] 13 illustrates an alternative configuration of a first cap having a contact surface according to certain embodiments of the present disclosure. [Figure 10C] 13 illustrates an alternative configuration of a first cap having a contact surface according to certain embodiments of the present disclosure. [Figure 10D] 13 illustrates an alternative configuration of a first cap having a contact surface according to certain embodiments of the present disclosure.

[0031] [Figure 11A] 1 is a cross-sectional view illustrating a contact surface of a first cap according to certain embodiments of the present disclosure. [Figure 11B] 1 is a cross-sectional view illustrating a contact surface of a first cap according to certain embodiments of the present disclosure. [Figure 11C] 1 is a cross-sectional view illustrating a contact surface of a first cap according to certain embodiments of the present disclosure. [Figure 11D] 1 is a cross-sectional view illustrating a contact surface of a first cap according to certain embodiments of the present disclosure.

[0032] Embodiments of the present disclosure and their corresponding advantages are best understood by referring to the following detailed description: Like reference numerals are used to identify like elements illustrated in one or more of the drawings, and it should be appreciated that the figures shown in the figures are intended to illustrate embodiments of the present disclosure and are not intended to limit the disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] The present disclosure relates to cells for energy storage devices. More specifically, the present disclosure relates to cells that have at least one electrode that is table-less, and thus can be used to form energy storage devices with reduced ohmic resistance and reduced cost. For example, in a jelly roll cell design, the negative electrode may include a conductive portion at one end that extends the length of the electrode and connects to the bottom of the can, electrically connecting the electrode to the can. In some embodiments, the can includes a cap with a specific design configured to increase the connection between the electrode and the cap. The cap may include ridges, bumps, cavities, or other features that provide additional connection between the cap and the electrode.

[0034] Reference will now be made in detail to certain aspects or features, examples of which are illustrated in the accompanying drawings. Wherever possible, corresponding or like reference numerals are used throughout the drawings to refer to the same or corresponding parts.

[0035] FIG. 1 illustrates a cell 100 according to certain embodiments of the present disclosure. In some embodiments, the cell 100 is embodied in the form of a secondary battery that can be recharged upon discharge and thus used multiple times. In other embodiments, aspects of the present disclosure can be similarly applied to fabricate primary batteries to minimize the cost of such primary batteries. Primary batteries include batteries that are typically not rechargeable and thus not suitable for reuse once discharged.

[0036] As shown in FIG. 1, the cell 100 includes a first substrate 102 having a first coating 110 disposed on one side of the first substrate 102. In some embodiments, the first coating 110 may be disposed on both sides of the first substrate 102. In some embodiments, the first substrate 102 is preferably embodied in the form of a laminate having a predetermined amount of thickness, for example, a thickness in the range of 0.01 to 1 millimeter (mm). In some embodiments, the first substrate 102 comprises a current collector. In some embodiments, the current collector comprises a metal foil. In some embodiments, the current collector comprises aluminum and / or copper.

[0037] In some embodiments, the first coating 110 may be a conductive coating having a first amount of conductivity. In some embodiments, the first coating 110 may be an electrode thin film. In some embodiments, the conductive coating comprises an electrode active material. In some embodiments, the electrode active material is a cathode active material. In some embodiments, the electrode active material is an anode active material. In some embodiments, the electrode active material is a silicon material (e.g., silicon metal and silicon dioxide), graphitic materials, graphite, graphene-containing materials, hard carbon, soft carbon, carbon nanotubes, porous carbon, conductive carbon, lithium nickel manganese cobalt oxide (NMC), lithium manganese oxide (LMO), lithium iron phosphate (LFP), lithium cobalt oxide (LCO), lithium titanate (LTO), lithium nickel cobalt aluminum oxide (NCA), layered transition metal oxides (LiCoO 2 (LCO), Li(NiMnCo)O 2 (NMC) and / or LiNi 0.8 Co 0.15 Al 0.05 O 2 (NCA), etc.), spinel manganese oxide (LiMn 2 O 4 (LMO) and / or LiMn 1.5 Ni 0.5 O 4 (LMNO), olivine (LiFePO 4 etc.), chalcogenides (LiTiS 2 ), Tavorite (LiFeSO 4 F), silicon, silicon oxide (SiOx), aluminum, tin, tin oxide (SnOx), manganese oxide (MnOx), molybdenum oxide (MoO 2 ), molybdenum disulfide (MoS 2 ), nickel oxide (NiOx), copper oxide (CuOx), and lithium sulfide (Li 2S), or a combination thereof. In some embodiments, the first coating further comprises a binder. In some embodiments, the first coating 110 may be disposed on the first substrate 102 by any means known to one of skill in the art. Some examples of disposing the first coating 110 on the first substrate 102 include, but are not limited to, mechanical deposition, electromechanical deposition, electrochemical deposition, or any combination of processes known to one of skill in the art.

[0038] Additionally or optionally, the first portion 112 of the first substrate 102, positioned midway along the width W of the first substrate 102, is coated with an electrically insulating material 114. In some embodiments, the electrically insulating material may be a polymeric insulating material. In some embodiments, the electrically insulating material may be a ceramic insulating material. In some embodiments, the ceramic insulating material includes a ceramic powder. In some embodiments, the electrically insulating material may be a ceramic powder such as polyethylene, polypropylene, aluminum oxide (e.g., Al 2 O 3 ), or a combination thereof. In some embodiments, the electrically insulating material further comprises a binder. In some embodiments, the electrically insulating material 114 may be disposed on both sides of the first substrate 102. In some embodiments, the insulating layer 114 is omitted. In certain embodiments, the first portion 112 of the first substrate 102 may be omitted. In such embodiments, the forming steps required to form the first portion 112 of the first substrate 102 may be omitted, such that the first substrate 102 only has the second portion 116, as described below. In some embodiments, the electrically insulating material may help reduce or prevent electrical contact between the first substrate 102, the first coating 110, and / or the conductive portion 118 and the second substrate 106 and / or the second coating.

[0039] A second portion 116 of the first substrate 102, disposed at an extreme or end position along the width W of the first substrate 102 (e.g., at a proximal end of the first substrate 102) and positioned adjacent to the first portion 112, comprises a conductive portion (i.e., conductor) 118. In some embodiments, the conductive portion 118 is an exposed area (e.g., a current collector) of the first substrate 102. In some embodiments, the conductive portion 118 consists of or consists essentially of the first substrate 102. In some embodiments, the conductive portion 118 is free of the first coating 110 and the insulating material 114. In some embodiments, the conductive portion 118 may be disposed on both sides of the first substrate 102.

[0040] 1 and also as shown in FIG. 2, the inner separator 104 is disposed over (e.g., stacked on) the first substrate 102. In some embodiments, the inner separator 104 is in the form of a laminate having a predetermined amount of thickness, for example, a thickness in the range of 0.01 to 0.05 millimeters (mm). In some embodiments, the inner separator is 10 μm, 15 μm, 20 μm, 30 μm, 40 μm, or 50 μm, or about 10 μm, about 15 μm, about 20 μm, about 30 μm, about 40 μm, or about 50 μm, or any value range therebetween (e.g., 10 to 15 μm). Further, in some embodiments, the inner separator 104 is electrically insulating. In some embodiments, the inner separator may include a polymeric material. In some embodiments, the inner separator may be selected from polyethylene, polypropylene, or a combination thereof. In some embodiments, the inner separator comprises multiple separator layers. In some embodiments, the inner separator comprises micropores.

[0041] 1 and also shown in FIG. 2, the second substrate 106 is disposed over (e.g., stacked on) the inner separator 104. The second substrate 106 has a second coating 120 disposed on one side of the second substrate 106. In some embodiments, the second coating 120 may be disposed on both sides of the second substrate 106. In some embodiments, the second substrate 106 is in the form of a laminate having a predetermined amount of thickness, for example, a thickness in the range of 0.01 to 1 millimeters (mm). In some embodiments, the second substrate 106 comprises a current collector (e.g., a foil).

[0042] The second coating 120 is a conductive coating having a second amount of conductivity. In some embodiments, the second coating 120 may be an electrode thin film. In some embodiments, the conductive coating includes an electrode active material. In some embodiments, the electrode active material is a cathode active material. In some embodiments, the electrode active material is an anode active material. In certain embodiments, the second coating 120 may be similar or the same as the first coating 110 and thus may have a similar or the same conductivity. In certain other embodiments, the second coating 120 may be different from the first coating 110 and thus may have a different conductivity. In some embodiments, the second coating 120 may be disposed on the second substrate 106 by any means known to one of skill in the art. Some examples of disposing the second coating 120 on the second substrate 106 include, but are not limited to, mechanical deposition, electromechanical deposition, electrochemical deposition, or any combination of processes known to one of skill in the art.

[0043] Continuing to refer to FIG. 1 and also as shown in FIG. 2, the outer separator 108 is disposed over (e.g., stacked on) the second substrate 106. In some embodiments, the outer separator 108 is in the form of a laminate having a predetermined amount of thickness, e.g., a thickness in the range of 0.01 to 0.05 millimeters (mm). Additionally, the outer separator 108 is electrically insulating. When the first substrate 102, the inner separator 104, the second substrate 106, and the outer separator 108 are stacked in a continuous manner, the first substrate 102, the inner separator 104, the second substrate 106, and the outer separator 108 are wound around a central axis AA' with the first substrate 102 located closest to the central axis AA', as best shown in FIG. 1. In some embodiments, there is no outer separator 108.

[0044] 2, a layout 200 of the first substrate 102, the inner separator 104, the second substrate 106, and the outer separator 108 to form the cell 100 of FIG. 1 is shown. In some embodiments, there is no outer separator 108. In certain embodiments, the inner and outer separators 104, 108 may be equal in length. In this embodiment, the inner and outer separators 104, 108 each have a length L 1 as shown in FIG. 1 In some embodiments, the length of the first substrate 102 is L 2 and the length of the second substrate 106 is L 3 In certain embodiments, the length L of the first substrate 102 may be 2 is the length L of the second substrate 106 3 (i.e., L 2 =L 3 ).

[0045] In certain embodiments, the length L of the first substrate 102 2 is the length L of the second substrate 106 3 may be different, i.e. not equal, to (i.e., L 2 ≠L 3 Furthermore, the length L of the first substrate 102 2is the length L of the second substrate 106 3 (i.e., L 2 ≠L 3 In some embodiments, the length of the inner separator 104 may be less than the length of the outer separator 108. In some embodiments, the length of the inner separator 104 is less than at least one of the first and second substrates 102, 106, yet still provides electrical insulation between the first and second substrates 102, 106.

[0046] With continued reference to FIG. 2, in certain embodiments, the length L of the second substrate 106 3 A portion 202 of the second substrate 106 disposed midway along the second substrate 106 may extend laterally relative to the mid-plane P of the second substrate 106 to form a conductive tab 122. Although one conductive tab 122 associated with the second substrate 106 is shown in FIGS. 1 and 2, in some embodiments, additional conductive tabs 122 may be present on the second substrate 106. In other embodiments, multiple portions of the second substrate 106 that are discrete from one another may extend laterally relative to the mid-plane P of the second substrate 106 to form multiple conductive tabs 122. It is envisioned that the presence of such multiple conductive tabs 122 on the second substrate 106 reduces the ohmic resistance of the cell 100 compared to the presence of a single conductive tab 122 on the second substrate 106.

[0047] The present disclosure offers many advantages over other advanced electrochemical cells that utilize tab contacts to electrically connect the negative electrode substrate to the can wall in addition to tabs to connect the positive electrode to the cathode connection. Eliminating the tab connection to the negative electrode and reorienting the conductive connection to conductive portion 118 allows the negative electrode to extend along the length of the negative electrode. This reduces the ohmic resistance from the negative electrode to the can, reduces current deviation along the length of the electrode, extends cell life, reduces Joule heating, and increases heat dissipation capabilities.

[0048] Equation 1 describes the relationship between the electrical resistance R (Ω) of a given material and its specific electrical resistivity ρ (Ω m), and is expressed as l (m) and A (m2 ) are the length and cross-sectional area of ​​the material, respectively. TIFF0007649736000001.tif14137

[0049] The electrical resistance of a given material is directly proportional to its length. Electrode tab contacts in conventional electrochemical cell designs are typically fixed at either the ends or the center of the wound electrode. Thus, to initiate an electrochemical reaction, current must travel lengthwise through the electrode current collector to reach the active material where the charge transfer reaction occurs. The distance the current travels can vary from half the length of the wound electrode when the tab is attached to the electrode's midpoint to the full length of the electrode when the tab is attached to either end. The embodiments included in the present disclosure can provide a more uniform electrical contact between the electrode current collector and the inner surface of the can. Thus, the maximum distance the current travels is the height of the electrode as opposed to its length. Depending on the cell form factor, the height of the electrode is typically 5% to 20% of its length. Thus, with embodiments of the present disclosure, the ohmic resistance at the negative electrode during electrochemical cycling can be reduced by a factor of 5 to 20.

[0050] Also, with electrochemical cells of embodiments according to the present disclosure, there may be significantly less current deviation, i.e., some electrode regions carry more or less current than others over the cycle life of the electrode. Current will preferentially follow the path of least resistance, which, barring other factors, will typically be along the path closer to the tab where resistance is least. Current deviation is highly undesirable in electrochemical cells because it can result in localized electrode hot spots where large overpotentials occur, resulting in undesirable chemical reactions that shorten the life of the cell. One example of such a reaction is the plating of metallic lithium on the negative electrode surface in a lithium-ion cell. The reduced ohmic resistance of the disclosed embodiments provides a cell environment that is more conducive to uniform current distribution and cell life.

[0051] Embodiments according to the present disclosure also provide superior heat generation and heat transfer characteristics over conventional electrochemical cell designs. Ohmic heating (W), the process of generating heat by passing an electric current through a medium, is given by Equation 2: TIFF0007649736000002.tif15137

[0052] Due to the aforementioned reduction in electrical resistance R, electrochemical cells of the present disclosure can be expected to generate significantly less ohmic heating than cells of conventional tub designs.

[0053] The following equation 3 describes the relationship between the thermal conductivity of a conductor and the intrinsic and extrinsic variables of the conductor. TIFF0007649736000003.tif15137

[0054] Here, Q(J s -1 ) is the heat transfer coefficient, k (W m -1 ·K -1 ) is the thermal conductivity of the material, A(m 2 ) and d(m) are the geometric dimensions where heat transfer occurs, and (T 2 -T 1 ) is the temperature difference across d. In a typical tab design electrochemical cell, the contact area from the tab to the can is typically small. For the cells of the disclosed embodiments, the contact area from the conductive portion 118 to the can is effectively 100% of the cell diameter. This allows for improved heat transfer through the base of the cell, and particularly from the negative electrode, in the disclosed embodiments due to the increased area over which the transfer occurs. The improved heat generation and transfer properties facilitate thermal management of the electrochemical cell. Managing the operating temperature of a cell is typically a critical aspect in optimizing the performance and extending the useful life of the cell.

[0055] Referring to FIG. 3A, an exemplary setup 300 that can be used to coat the first substrate 102 is depicted. In certain embodiments, when manufacturing the first substrate 102, it is possible to manufacture multiple first substrates 102 by stacking individual first substrates 102 in tandem, beside or on top of each other. A portion of each first substrate 102 is coated with a first coating 110. Additionally or optionally, an electrically insulating material 114 is coated beside the first coating 110, i.e., onto the first portion 112 of each first substrate 102, and a conductive portion 118 is coated beside the first portion 112 of each first substrate 102, i.e., onto the corresponding second portion 116 of each first substrate 102. In some embodiments, the insulating material 214 may be omitted, as shown in FIG. 3B. When manufacturing the first substrate 102, this stacking of multiple first substrates 102 beside or on top of each other can help a manufacturer save time and offset costs that would otherwise be incurred if the manufacturer were to form each first substrate 102 using individual sections of a laminate and coat the first portion 112 and second portion 116 of such individual laminates with conductors to form the electrically insulating material 114 and conductive portion 118, respectively.

[0056] The drawing of FIG. 3A shows three first substrates 102 wound alongside each other in tandem via an exemplary configuration 300. The illustrated setup 300 includes rollers 302 and a coating tool 304 that can cooperate with a timing mechanism (not shown) to coat the first substrates 102 at predetermined positions to obtain a desired portion and length of the first substrate 102. The three first substrates 102 may be separated from each other, for example, using a crimped margin (not shown) between adjacent first substrates 102, or automated using a separate shearing process performed before the multiple first substrates 102 enter the exemplary setup 300 of FIG. 3A, or after they exit the exemplary setup 300 of FIG. 3A as a multiple first substrates 102 of a joined desired length. In some embodiments, the shearing may occur using a shearing tool as the coating is performed. In some embodiments, prior to shearing, the coated substrate is baked before shearing with the shearing tool.

[0057] In certain embodiments, as shown in FIG. 4, a first cap 402 having a contact surface 404 is shown. In certain embodiments, the first cap 402 is made from nickel. In other embodiments, the first cap 402 is made from a Ni-based alloy. The contact surface 404 of the first cap 402 is constructed to correspond to and connect with the conductive portion 118 of the rolled first substrate 102. In some embodiments, an insulating material is placed on the opposite side of the can to create a compressive force that ensures that the conductive portion 118 and the first cap 402 make good electrical contact. The insulating material may be placed on top of the can or near the positive terminal to create the compressive force. In other embodiments, the anode swells with an electrolyte to press the jelly roll against the can, which helps ensure that the conductive portion 118 forms good electrical contact with the first cap 402. In some embodiments, the conductive portion 118 is welded to the first cap 402. In some embodiments, the welding is performed by laser welding and / or ultrasonic welding. In certain embodiments, as depicted in the drawing of Figure 4, the contact surface 404 is contoured in the shape of concentric grooves 406. These grooves 406 may each have a size in the range of 0.01 to 0.1 millimeters (mm) to correspond to the thickness of the first substrate 102, as these grooves 406 interface with the conductive portion 118 of the first substrate 102 that is to be wound.

[0058] Referring to FIG. 5, a can 502 is shown that can be used to encapsulate the first substrate 102, inner separator 104, second substrate 106, and outer separator 108 of the cell 100 with the first cap 402. In some embodiments, the can 502 does not include the outer separator 108, and the conductive portion 118 may be connected directly to the can. In some embodiments, the can 502 has a first end 504 and a second end 506. In some embodiments, the first and second ends 504, 506 are each open ended. In some embodiments, the first end 504 of the can 502 is adapted to receive the first cap 402, while the second end 506 of the can 502 is adapted to receive a second cap (not shown) that connects with the conductive tab 122 of the second substrate 106. In some embodiments, at least one of the first and second ends is closed, and the can 502 includes a bottom wall and / or a top wall.

[0059] 6A shows a cross-sectional view of a first end of a can 502 with a cell having a conductive portion 118 in contact with a contact surface 404 of a first cap 402, where the conductive portion 118 is shown bent when pressed up against the first cap 402. However, if the conductive portion 118 is formed at the bottom of the jelly roll, there may be imperfections (such as a conductor folded over on itself) that may make the connection between the conductive portion 118 and the first cap more difficult. In some embodiments, features may be created by removing a portion of the end of the conductive portion, as shown in FIGS. 6B-6E, to create a more robust connection between the conductive portion 118 and the first cap. While the drawing in FIG. 6A shows the bottom portion of the cell 100 including the first cap 402, in other embodiments, the first cap 402 is omitted and instead the conductive portions 118 of the rolled first substrate 102 connect with each other and with the bottom wall 602 of the cell 100 as shown in the cross-sectional view of the first end of the can with the cell in FIG. 6B. In some embodiments, the conductive portions 118 may be of a pre-specified width and spaced apart from each other at a pre-specified distance, for example, a fixed width and a fixed distance as shown in the cell cross-sectional view in FIG. 6C. In some embodiments, the conductive portions 118 may be of gradually increasing width and spaced apart as shown in the cell cross-sectional view in FIG. 6D, so that when rolled into the can 506, they connect with the bottom wall 602 of the cell 100 at a constant width and spaced apart from each other as shown in the cell bottom view in FIG. 6E. FIG. 7 illustrates a method 700 for manufacturing a cell 100 according to certain embodiments of the present disclosure. As shown in step 702, the method 700 includes providing a first substrate 102 with a first coating 110 thereon. In step 704, the method 700 further includes laminating an inner separator 104 onto the first substrate 102. In step 706, the method 700 includes providing a second substrate 106 having a second coating 120 disposed thereon. In step 708, the method 700 further includes laminating the second substrate 106 onto the inner separator 104.At step 710, the method 700 further includes stacking the outer separator 108 onto the second substrate 106 such that the first substrate 102, the inner separator 104, the second substrate 106, and the outer separator 108 are stacked in a continuous manner. In some embodiments, step 710 is omitted and the can does not include the outer separator 108. At step 712, the method 700 includes rolling the first substrate 102, the inner separator 104, the second substrate 106, and the outer separator 108 about a central axis (e.g., AA') such that the location of the first substrate 102 is closest to the central axis (e.g., AA').

[0060] In certain embodiments, according to the method 700 of FIG. 7 and as depicted in the drawings of FIGS. 1 and 2, a first substrate 102 is used to form the anode 124 of the cell 100, while a second substrate 106 is used to form the cathode 126 of the cell 100.

[0061] However, as shown in Figures 8 and 9, a cell 700 according to an embodiment of the present disclosure has the anode 124 and cathode 126 inverted, i.e., swapped, such that the cathode 126 is closest to the central axis AA'. Corresponding to such a modification, the contact surface of the first cap may be changed to appropriately correspond to the conductive portion 118 of the first substrate 102. The drawings in Figures 10A-10D show several examples of alternative configurations of the first cap 1002, 1004, 1006, and 1008, and their respective contact surfaces 1003, 1005, 1007, and 1009. In some embodiments, the first cap is attached to an open end of the can. In some embodiments, the first cap and its corresponding contact surface are the bottom or top wall of the can. In some embodiments, the topography of the cap may be formed by a stamping process. In some embodiments, to provide better contact between the conductive portion 118 and the first cap, there is a spring-loaded cantilever mechanism (or similar mechanism) under the disk of the cap to provide an upward force to the contact surface.

[0062] Additionally, in certain embodiments, the first cap, for example the first cap 1004 as depicted in the drawing of FIG. 10B, has a cantilevered cross-section that further provides resilience against mechanical shocks and vibrations that the cell 100 may encounter during use. In some embodiments, first caps such as those depicted at 1002, 1004, 1006, and 1008 in FIGS. 10A-10D may be used. In other embodiments, the cross-sectional views of the first caps depicted in FIGS. 11A-11D may be defined by the illustrated contact surfaces 1100, 1102, 1104, and 1106 of the first cap. These first caps exhibit contact surfaces that are columnar, pyramidal, spike-shaped, and other shapes suitable for connecting to the conductive portion 118 of the wrapped first substrate 102.

[0063] The above disclosure is not intended to limit the disclosure to the precise forms or embodiments disclosed herein. Thus, it is contemplated that various alternative forms, embodiments, and / or modifications may be made in light of the disclosure, whether expressly described or implied herein. Thus, although embodiments of the disclosure have been described, those skilled in the art will recognize that changes in form and detail may be made without departing from the scope of the disclosure.

[0064] In the above specification, the present disclosure has been described with reference to specific embodiments. However, as will be recognized by those skilled in the art, the various embodiments disclosed herein can be modified or otherwise implemented in various other ways without departing from the spirit and scope of the present disclosure. This specification should therefore be considered as illustrative and is intended to teach those skilled in the art how to make and use the various embodiments of the disclosed battery system. It should be understood that the forms of the disclosure shown and described herein are to be taken as representative embodiments. Equivalent elements or materials may be substituted for those typically shown and described herein. Moreover, certain features of the present disclosure may be utilized independently of the use of other features, all of which will be apparent to those skilled in the art after having the benefit of this specification of the present disclosure. The terms "including," "comprising," "incorporating," "consisting of," "have," "is," and the like, used to describe and claim this disclosure, are intended to be construed in a non-exclusive manner, i.e., in anticipation of the presence of items, components or elements not expressly stated. References to the singular should also be construed to refer to the plural.

[0065] Furthermore, the various embodiments disclosed herein should be construed in an illustrative and explanatory sense, and should not be construed as limiting the present disclosure in any way. Junction-related references (e.g., connected, associated, coupled, and the like) are used only to aid the reader in understanding the present disclosure, and do not create limitations on the position, orientation, or use of the elements specifically disclosed herein. Thus, junction-related references, if any, should be construed broadly. Moreover, such junction-related references may not necessarily infer that two elements are directly connected to each other.

[0066] Additionally, all numerical terms, such as, but not limited to, "first," "second," "one," "another," or any other conventional and / or numerical terminology, should be construed merely as identifiers to aid the reader in understanding the various elements, embodiments, variations and / or modifications of the present disclosure, and in no way may create any limitation whatsoever, particularly with respect to the order or preference of other elements, embodiments, variations and / or modifications with respect to or over other elements, embodiments, variations and / or modifications.

[0067] It will also be appreciated that one or more of the elements shown in the drawings / figures may be implemented in a more separated or integrated manner, or may be eliminated in certain instances, as may be more useful in a particular application.

Claims

1. An energy storage device, comprising: a cell of the energy storage device; The cell comprises: a first substrate having a proximal end and a distal end, the first substrate comprising a first portion and a second portion, the first portion being distal to the second portion and the second portion comprising a conductor located at the proximal end, the conductor comprising a plurality of conductive portions, each of the conductive portions having a width, each of the conductive portions being spaced apart from one another by a non-conductive portion; A second substrate; an inner separator disposed between the first substrate and the second substrate; a can having a first end and a second end, the first end including a first cap having a contact surface; Equipped with the first substrate, the inner separator and the second substrate are wound around a central axis to form a cell; each of the spaced apart conductive portions is curved; the conductive portions of the first substrate are arranged in a concentric circular pattern; each of the spaced apart conductive portions substantially contacting the first cap.

2. The device of claim 1 , wherein the electrical conductor consists essentially of the first substrate.

3. The device of claim 1 , wherein the first substrate is a current collector.

4. The device of claim 1 , wherein the first substrate is aligned closest to the central axis as it is rolled.

5. 10. The energy storage device of claim 1, wherein the second substrate is aligned closest to the central axis as it is rolled.

6. The device of claim 1 , wherein the first portion is located between a first coating and the second portion and is coated with an electrically insulating material.

7. The device of claim 6 , wherein the second portion is positioned adjacent to the first portion.

8. The device of claim 1 , wherein the second substrate further comprises a conductive tab.

9. The device of claim 8 , wherein the conductive tab is disposed midway along a length of the second substrate and extends across a midplane of the second substrate.

10. The device of claim 1 , wherein the first substrate forms one of an anode and a cathode, and the second substrate forms the other of the anode and the cathode.

11. The device of claim 1 , wherein the electrical conductor is in electrical contact with the contact surface.

12. The device of claim 1 , wherein the first end comprises a bottom wall.

13. The device of claim 1 , wherein the first and second ends are each open ended.

14. The device of claim 13 , wherein the first end of the can is configured to receive the first cap.

15. The device of claim 1 , wherein the second end of the can is configured to receive a second cap.

16. The device of claim 1 , wherein the first cap comprises at least one of nickel (Ni) and a Ni-based alloy.

17. The device of claim 1 , wherein the contact surface of the first cap comprises a weld that electrically connects with the second portion.

18. 13. A method for forming the energy storage device of claim 1, comprising: disposing the inner separator over the first substrate; placing the second substrate over the inner separator; and winding the first substrate, the inner separator and the second substrate disposed on top of each other about a central axis to form the cell.

19. The method of claim 18 , wherein the location of the first substrate is closest to the central axis.

20. The method of claim 18 , wherein the position of the second substrate is closest to the central axis.

21. The method of claim 18 , wherein the first substrate, the inner separator and the second substrate are disposed on top of one another in succession.

22. The method of claim 18 further comprising coating the first portion with an electrically insulating material.

23. The method of claim 22 , wherein the second portion is positioned adjacent to the first portion.

24. 20. The method of claim 18, further comprising extending a portion of the second substrate across a mid-plane of the second substrate to form a conductive tab midway along the length of the second substrate.

25. 1. A method of forming an energy storage device, comprising: A method according to claim 18; placing a cell within said can.

26. 26. The method of claim 25, further comprising the step of electrically connecting the electrical conductor with the contact surface.

27. The device of claim 1 , wherein each of the conductive portions has a gradually increasing width.

28. The device of claim 1 , wherein each of the conductive portions are spaced apart by incrementally increasing distances.

29. An energy storage device comprising: a cell of the energy storage device; The cell comprises: a first substrate having a proximal end and a distal end, the first substrate comprising a first portion and a second portion, the first portion being distal to the second portion and the second portion comprising a conductor located at the proximal end, the conductor comprising a plurality of conductive portions, each of the conductive portions having a width, each of the conductive portions being spaced apart from one another by a non-conductive portion; A second substrate; an inner separator disposed between the first substrate and the second substrate; a can having a first end and a second end, the first end including a first cap having a contact surface; Equipped with the first substrate, the inner separator and the second substrate are wound around a central axis to form a cell; each of the spaced apart conductive portions is curved; the conductive portions of the first substrate are arranged in a concentric circular pattern; The concentric pattern is in contact with the first cap.

30. An energy storage device comprising: a cell of the energy storage device; The cell comprises: a first substrate having a proximal end and a distal end, the first substrate comprising a first portion and a second portion, the first portion being distal to the second portion and the second portion comprising a conductor located at the proximal end, the conductor comprising a plurality of conductive portions, each of the conductive portions having a width, each of the conductive portions being spaced apart from one another by a non-conductive portion; A second substrate; an inner separator disposed between the first substrate and the second substrate; a can having a first end and a second end, the first end including a first cap having a contact surface; Equipped with the first substrate, the inner separator and the second substrate are wound around a central axis to form a cell; each of the spaced apart conductive portions is curved; the conductive portions of the first substrate are arranged in a concentric circular pattern; The contact surface of the first cap comprises a spiral-shaped groove.

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