Electrically floating support inserts for energy storage devices, and methods thereof

Abstract

A floating support insert that is not tied to an electrode and electrically "floats" in between the anode and cathode potentials is utilized to support the inner diameter (i.e., "ID") of an electrode assembly (e.g., jelly roll (i.e., "JR")) and / or a cylindrical energy storage device. A floating support insert may be positioned within a cylindrical void of the electrode assembly, further include a conductive support material and be electrically insulated from each of the anode and the cathode.

Description

PATENT ELECTRICALLY FLOATING SUPPORT INSERTS FOR ENERGY STORAGE DEVICES, AND METHODS THEREOF INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

[0001] Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet or PCT Request as filed with the present application are hereby incorporated by reference under 37 CFR 1.57, and Rules 4.18 and 20.6. This application claims the benefit of U.S. Provisional Application No. 63 / 701,268, filed on September 30, 2024, which is incorporated by reference herein in its entirety for all purposes. BACKGROUND

[0002] Many types of energy storage devices (e.g., batteries) are currently used in electric vehicles and energy-storage applications. Many energy storage devices use a jelly roll design in which the cathode, anode, and separator are wound or rolled together to form an electrode assembly, and connected to the positive and negative terminals of the energy storage device housing. Generally, wound electrode films may include imperfections (e.g., a natural kink, weak point, stress point, and / or electrode buckling zone) that affect the circularity of the electrode assembly, which in turn may affect the lifetime of the energy storage device. For example, electrode buckling within the inner diameter of the jelly roll can lead to lithium plating, performance degradation, shorting and / or thermal run away.

[0003] As such, improving electrode assembly circularity and preventing electrode buckling with the inner diameter of a jelly roll may be beneficial. SUMMARY

[0004] For purposes of summarizing the disclosure and the advantages achieved over the prior art, certain objects and advantages of the disclosure are described herein. Not all such objects or advantages may be achieved in any particular embodiment. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.

[0005] All of these embodiments are intended to be within the scope of the invention herein disclosed. These and other embodiments will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiments having reference to the attached figures, the invention not being limited to any particular preferred embodiment(s) disclosed.

[0006] In one aspect, a wound electrode assembly is described. The wound electrode assembly includes: a cathode, an anode, a separator positioned between the anode and cathode, wherein the cathode, the anode and the separator are wound about a central axis to form an inner diameter surface surrounding a cylindrical void, and a floating support insert positioned within the cylindrical void, wherein the floating support insert comprises a conductive support material, and wherein the floating support insert is electrically insulated from each of the anode and the cathode.

[0007] In some embodiments, the conductive support material is selected from the group consisting of stainless steel, aluminum, nickel, and combinations thereof. In some embodiments, the floating support insert further comprises a coating material. In some embodiments, the coating material is selected from the group consisting of a nickel plated coating, a chrome plated coating, a metal cladding, a stainless steel coating, a low carbon steel coating, a copper coating, an aluminum coating, a polymer coating, and combinations thereof.

[0008] In some embodiments, the floating support insert has an open circuit potential (OCP) vs. Li / Li+of about 2.5 V to about 4 V. In some embodiments, the floating support insert has a corrosion current density in a service potential range above OCP to 4.0 V vs. Li / Li+of about 0.1 mA / cm2to about 1.1 mA / cm2. In some embodiments, the floating support insert has a vs. Li / Li+pitting potential of about 3.5 V to about 5 V. In some embodiments, the floating support insert is substantially corrosion resistant under soaking in an electrolyte containing 500 ppm HF at 55°C for about 10-20 days. In some embodiments, the floating support insert further includes an intervening insulating material coating.

[0009] In another aspect, an energy storage device is described. The energy storage device includes: a wound electrode assembly, an electrolyte and a housing, wherein the wound electrode assembly and the electrolyte are positioned within the housing.

[0010] In some embodiments, the floating support insert has no substantive electrochemical reaction with lithium in a service potential range below OCP to 0 V vs. Li / Li+.In some embodiments, the floating support insert has a current density between OCP and 0.005 V vs. Li / Li+of about 0.05 mA / cm2to about 0.6 mA / cm2. In some embodiments, the floating support insert has a charge consumption when cycled between 0.0 V and 1.25 V vs. Li / Li+three times starting from OCP for cycle 0 of about 0.5 mAh / cm2to about 3.5 mAh / cm2.

[0011] In another aspect, a method of forming a wound electrode assembly is described. The method includes: positioning a separator between an anode and a cathode to form an electrode assembly, winding the separator, the cathode, the anode about a central axis to form an inner diameter surface of the electrode assembly surrounding a cylindrical void, and positioning a floating support insert within the cylindrical void of the electrode assembly after winding to form a wound electrode assembly.

[0012] In some embodiments, the method further includes disposing an intervening insulating material coating over the floating support insert. In some embodiments, positioning the floating support insert within the cylindrical void of the electrode assembly includes physically contacting the floating support insert with the cathode and the anode. In some embodiments, positioning the floating support insert within the cylindrical void of the electrode assembly includes avoiding physically contacting the floating support insert with the cathode and the anode. In some embodiments, positioning the floating support insert within the cylindrical void of the electrode assembly includes utilizing an insertion device to position the floating support insert within the cylindrical void. In some embodiments, the inner diameter surface of the electrode assembly is processed prior to insertion of the floating support insert.

[0013] In another aspect, a method of forming an energy storage device is disclosed. The method includes: disposing a wound electrode assembly and an electrolyte within a housing to form the energy storage device.

[0014] In some embodiments, the method further includes positioning the floating support insert within the cylindrical void after disposing the wound electrode assembly within the housing. In some embodiments, the method further includes positioning the floating support insert within the cylindrical void before disposing the wound electrode assembly within the housing. In some embodiments, the method further includes positioning the floating support insert within the cylindrical void concurrently with disposing the wound electrode assembly within the housing.BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG.1A is a schematic illustration showing a horizontal cross-section of an energy storage device, according to some embodiments.

[0016] FIG.1B is a schematic illustration showing a side view of an energy storage device and a support insert, according to some embodiments.

[0017] FIG. 2A is a graph showing first formation cycle voltages and voltage potentials for a full cell energy storage device, the anode and the cathode, according to some embodiments.

[0018] FIG.2B is a graph showing cycling voltages vs. current for a full cell energy storage device, the anode and the cathode, according to some embodiments.

[0019] FIG.3 is a graph showing cycling voltages vs. corrosion current density for stainless steel, according to some embodiments.

[0020] FIG. 4A are images of corrosion soaking tests on low carbon steel with a nominal electrolyte, according to some embodiments.

[0021] FIG. 4B are images of corrosion soaking tests on low carbon steel with an electrolyte including water, according to some embodiments.

[0022] FIG. 5A are images of corrosion soaking tests on stainless steel with a nominal electrolyte, according to some embodiments.

[0023] FIG. 5B are images of corrosion soaking tests on stainless steel with an electrolyte including water, according to some embodiments.

[0024] FIG.6A is a graph of a cyclic voltammetry scan of stainless steel, according to some embodiments.

[0025] FIG.6B is an enlarged graph of a cyclic voltammetry scan of stainless steel from FIG.6A, according to some embodiments.

[0026] FIG.7A is a graph showing voltage and auxiliary voltage cycling of a pouch cell with a floating stainless steel insert.

[0027] FIG. 7B is a graph showing voltage cycling of a pouch cell with a floating stainless steel insert.

[0028] FIG.7C is an image of a stainless steel insert post-cycling.

[0029] FIG. 8A is a bar graph showing simulated formation total coulombic efficiencies for inserts made from different metals, according to some embodiments.

[0030] FIG. 8B is a bar graph showing simulated formation total charge consumptions for inserts made from different metals, according to some embodiments.

[0031] FIG.9A is a graph showing voltage vs. current densities of nickel 200 tested in a jar cell, according to some embodiments.

[0032] FIG. 9B is a graph showing voltage vs. current densities of 304 stainless steel tested in a jar cell, according to some embodiments.

[0033] FIG. 9C is a graph showing voltage vs. current densities of 316 stainless steel tested in a jar cell, according to some embodiments.

[0034] FIG. 9D is a graph showing voltage vs. current densities of 430 stainless steel tested in a jar cell, according to some embodiments.

[0035] FIG.9E is a graph showing voltage vs. current densities of 1010 low carbon steel tested in a jar cell, according to some embodiments.

[0036] FIG. 10A is a graph showing corrosion resistance kinetics of aluminum, copper and nickel plated steel (NPS) in a nominal electrolyte, according to some embodiments.

[0037] FIG. 10B is a graph of showing corrosion resistance kinetics of aluminum in a nominal electrolyte after multiple voltage cycles, according to some embodiments.

[0038] FIG. 11 is a graph showing metal stability at open circuit potential of aluminum, copper and nickel plated steel (NPS) in a nominal electrolyte, according to some embodiments.

[0039] FIG.12A is a graph showing copper dissolution in an electrolyte including various amounts of hydrofluoric acid at 25°C on average, according to some embodiments.

[0040] FIG.12B is a graph showing copper dissolution in an electrolyte including various amounts of hydrofluoric acid at 55°C on average, according to some embodiments.

[0041] FIG.13A is an image of a corrosion test of a copper sample with a nominal electrolyte after ten days at 55°C, according to some embodiments.

[0042] FIG. 13B is an image of a corrosion test of a copper sample with an electrolyte including 200 ppm of hydrofluoric acid after ten days at 55°C, according to some embodiments.

[0043] FIG. 13C is an image of a corrosion test of a copper sample with an electrolyte including 400 ppm of hydrofluoric acid after ten days at 55°C, according to some embodiments.

[0044] FIG. 14A is an image of a corrosion test of an aluminum sample with a nominal electrolyte after two days at 55°C, according to some embodiments.

[0045] FIG. 14B is an image of a corrosion test of an aluminum sample with a nominal electrolyte after ten days at 55°C, according to some embodiments.

[0046] FIG. 14C is an image of a corrosion test of an aluminum sample with an electrolyte including 200 ppm of hydrofluoric acid after ten days at 55°C, according to some embodiments.

[0047] FIG. 14D is an image of a corrosion test of an aluminum sample with an electrolyte including 400 ppm of hydrofluoric acid after ten days at 55°C, according to some embodiments. DETAILED DESCRIPTION

[0048] The present disclosure may be understood by reference to the following detailed description. It is noted that, for purposes of illustrative clarity, certain elements in various drawings may not be drawn to scale, may be represented schematically or conceptually, or otherwise may not correspond exactly to certain physical configurations of embodiments.

[0049] In order to support the inner diameter of an electrode assembly (e.g., jelly roll (i.e., “JR”)) and / or a cylindrical energy storage device, an electrically floating support may be inserted with the inner diameter (i.e., “ID”). As opposed to electrically conductive support inserts tied to an electrode potential (e.g., anode potential), which may require added complexity and / or additional components during assembly of the energy storage device, or non-conductive support inserts, which may have limits on strength and / or stiffness and may decrease the energy density of an energy storage device, a conductive support insert that is not tied to an electrode and electrically “floats” in between the anode and cathode potentials is utilized. Although such electrically floating supports were seen as guaranteeing metal dissolution and plating, which can lead to cell shorts and capacity fading, the present disclosure unexpectedly demonstrates that with careful material selection dissolution and plating can be minimized, substantially minimized, avoided or significantly avoided. As such, electrically floating support inserts may significantly reduce cost and assembly complexity while avoiding electrode buckling that can lead to lithium plating, performance degradation, shorting and / or thermal run away.

[0050] The electrically floating support insert includes an electrically conductive support material (e.g., metal), and the electrically floating support insert is not in direct electrical communication with an electrode. For example, in some embodiments although the electrically floating support insert may be in contact with an electrolyte, it would not be in direct contact with an electrode (e.g., anode, cathode) or other conductive elements in contact with the electrodes (e.g., electrode tabs, electrode lids, energy storage device housing). As another example, in some embodiments the electrically floating support insert may be in physical contact with an electrode or other conductive elements in contact with the electrode, but is not in electrical communication due to an intervening insulating material (e.g., insulating coating).

[0051] In some embodiments, intimate contact by the floating support insert with the inner diameter is achieved prior to, subsequent to and / or concurrently with winding of the electrode assembly and / or operating the energy storage device (e.g., formation cycle, swelling). Such a floating support insert may support or aid in providing structural support to the inner diameter of the electrode assembly, and may prevent or aid in preventing electrode buckling as the cell swells due to cell cycling. FIGS. 1A and 1B are a schematic illustrations showing an energy storage device, where a jellyroll is positioned within a can and a floating support insert is positioned within the inner diameter of the jellyroll.

[0052] Furthermore, in some embodiments the floating support insert enables or aids in thermal transfer from the center of a cell, maintains a thermal runaway chimney, increases stiffness at an inner diameter and / or allows for compliance or flexibility during cell swelling. In some embodiments, as the electrode assembly swells, the floating support insert continues to contact the inner diameter and provide structural support while simultaneously being flexible and compliant enough to allow for swelling to occur. In some embodiments, the floating support insert is configured to allow for inspection of the inner diameter after installation of the post-winding support. Materials

[0053] The material(s) of the electrically floating support insert may be selected to provide a balance between stiffness and compliance, to resist degradation and contamination during operation, and / or operate throughout or substantially throughout the lifetime of theenergy storage device. For example, in some embodiments the material is selected to resist, avoid or substantially avoid degradation, corrosion, plating or otherwise react with the electrolyte during operating conditions of the energy storage device, as well as in conditions where the electrolyte is contaminated (e.g., with water and / or hydrofluoric acid (“HF”)).

[0054] In some embodiments, the support material may include a metal, an alloy, or combinations thereof. In some embodiments, the metal or alloy is selected from a stainless steel, a low carbon steel, copper, aluminum, nickel, alloys thereof, or combinations thereof. In some embodiments, the stainless steel is an austenitic stainless steel (e.g.200 series, 300 series) and / or a martensitic stainless steel (400 series). In some embodiments, the support material is coated with a coating material. In some embodiments, the coating material includes a nickel plated coating (e.g., nickel plated carbon steel), a chrome plated coating, a metal cladding, a stainless steel coating, a low carbon steel coating, a copper coating, an aluminum coating, and / or a polymer coating.

[0055] In some embodiments, the electrically floating support insert and / or support material has a stiffness of, of about, of at least, or of at least about, 100 GPa, 150 GPa, 200 GPa, 250 GPa, 300 GPa, 350 GPa, 400 GPa or 500 GPa, or any range of values therebetween. In some embodiments, the support material has a yield strength of, of about, of at least, or of at least about, 100 MPa, 150 MPa, 200 MPa, 250 MPa, 300 MPa, 350 MPa, 400 MPa, 500 MPa, 600 MPa, 700 MPa, 800 MPa, 900 MPa, 1 GPa or 1.5 GPa, or any range of values therebetween.

[0056] In some embodiments, the electrically floating support insert and / or support material has an open circuit potential (OCP) vs. Li / Li+ of, of about, of at least, or of at least about, 1.0 V, 1.1 V, 1.5 V, 2 V, 2.2 V, 2.5 V, 2.8 V, 3.0 V, 3.2 V, 3.5 V, 3.8 V, 4.0 V or 4.5 V, or any range of values therebetween. In some embodiments, the electrically floating support insert and / or support material has an exchange current density at open circuit vs. Li / Li+(e.g., according to the Tafel approximation fit) of, of about, of at most, or of at most about, 0.01x10-3mA / cm2, 0.1x10-3mA / cm2, 0.5x10-3mA / cm2, 1x10-3mA / cm2, 2x10-3mA / cm2, 3x10-3mA / cm2, 4x10-3mA / cm2, 5x10-3mA / cm2or 6x10-3mA / cm2, or any range of values therebetween. In some embodiments, the electrically floating support insert and / or support material has a corrosion current in the service potential range above OCP to 4.0V vs. Li / Li+ (e.g., tested in linear sweep voltammetry rising from OCP at 1mV / s) of, of about, of at most,or of at most about, 0.1 mA / cm2, 0.2 mA / cm2, 0.5 mA / cm2, 0.8 mA / cm2, 0.9 mA / cm2, 1 mA / cm2or 1.1 mA / cm2, or any range of values therebetween. In some embodiments, the electrically floating support insert and / or support material has a vs. Li / Li+pitting potential (e.g., a potential at which corrosion current rapidly increases by orders of magnitude for small increases in potential) of, of about, of at least, or of at least about, 3.5V, 3.8V, 3.9V, 4.0V, 4.2V, 4.5V or 5.0V, or any range of values therebetween. In some embodiments, the electrically floating support insert and / or support material has no substantive electrochemical reaction with lithium in the service potential range below OCP to 0V vs. Li / Li+and decreasing reactions with electrolyte over multiple cycles. In some embodiments, the electrically floating support insert and / or support material has a current density between OCP and 0.005 V vs. Li / Li+of, of about, of at most, or of at most about, 0.05 mA / cm2, 0.1 mA / cm2, 0.2 mA / cm2, 0.3 mA / cm2, 0.4 mA / cm2, 0.5 mA / cm2or 0.6 mA / cm2, or any range of values therebetween. In some embodiments, the electrically floating support insert and / or support material has a charge consumption when cycled between 0.0V and 1.25V vs. Li / Li+three times starting from OCP for cycle 0 of, of about, of at most, or of at most about, 0.5 mAh / cm2, 1 mAh / cm2, 1.5 mAh / cm2, 2 mAh / cm2, 2.5 mAh / cm2, 2.9 mAh / cm2, 3 mAh / cm2, 3.1 mAh / cm2or 3.5 mAh / cm2, or any range of values therebetween. In some embodiments, the electrically floating support insert and / or support material has no substantive signs of pitting and / or corrosion as observed by optical microscopy when soaked in electrolyte containing 500 ppm HF at 55°C for, for about, for at least, or for at least about, 10 days, 11 days, 12 days, 13 days, 14 days, 15 days, 16 days, 18 days or 20 days, or any range of values therebetween.

[0057] Although the electrically floating support insert is floating and not in direct electrical communication with the anode or cathode, the electrically floating support insert may experience electrochemical potentials through the electrolyte through proximity to the anode or cathode. As such, the electrically floating support insert must be able to withstand or substantially withstand such voltage potentials without unacceptably large side reactions, plating and / or corrosion. FIG. 2A shows the first formation cycle voltages and voltage potentials for a full cell energy storage device, the anode and the cathode of an example energy storage device. During the first formation cycle, the anode shows a voltage potential range of about 0.005–1 V vs. Li / Li+, as assembled, the anode shows a voltage potential of about 3.2 V vs. Li / Li+, and during formation, the anode shows a voltage potential of about 0.075-0.83 Vvs. Li / Li+. During the first formation cycle the cathode shows a voltage potential range of about 3-4.4 V vs. Li / Li+, and during formation the cathode shows a voltage potential of about 3.35–4.33 V. FIG. 2B shows the equilibrium cycle voltages for a full cell energy storage device, the anode and the cathode of an example energy storage device, where the typical operating anode potential range is about 50mV-1V vs. Li / Li+suggesting a test range of about 0.0-1.25V vs. Li / Li+to identify possible side reactions in addition to lithium plating kinetics, and the typical operating cathode potential range is about 3.5-4.4V vs. Li / Li+suggesting a test range of about 3-4.5V vs. Li / Li+. Assembly

[0058] In some embodiments, the electrically floating support insert is positioned or configured to be positioned within the inner diameter of the electrode assembly prior to, subsequent to or concurrently with winding of the electrode assembly. In some embodiments, the electrically floating support insert is positioned in the inner diameter before and / or after the electrode assembly is positioned within the housing, the housing is filled with electrolyte, the electrode assembly is electrically connected to the housing, lid(s) and / or tab(s), or combinations thereof. In some embodiments, the electrically floating support insert is positioned within the inner diameter with the aid of an insertion device, wherein the insertion device is removed after insertion. In some embodiments, the inner diameter of the electrode assembly is processed prior to insertion of the electrically floating support insert, for example such as moving and / or heating the separator, anode and / or cathode layers. Electrode Materials, Electrode Films, Electrodes and Energy Storage Devices

[0059] An electrode film mixture and electrode films formed using materials are described herein. In some embodiments, components of an active layer or electrode film may comprise particles, such as a composite material. The particles for forming the active layer or electrode film may be combined with a material to provide an electrode film mixture. In some embodiments, the active layer or electrode film may be formed from the electrode film mixture such that weight percentages of the components of the active layer or electrode film and weight percentages of the components of the electrode film mixture are substantially the same.

[0060] An active material (e.g., cathode active material, anode active material) may be used in the preparation of an electrode film and / or electrode for an energy storage device. In some embodiments, an electrode comprises a current collector and an electrode film.

[0061] In some embodiments, the active material is a cathode active material. In some embodiments, the cathode active material is selected from at least one of a metal oxide, metal sulfide, a sulfur-carbon composite, a lithium metal oxide, and a material including sulfur. In some embodiments, the cathode active material is selected from lithium iron phosphate (i.e., LiFePO4or “LFP”), lithium manganese iron phosphate (e.g., LiMn0.6Fe0.4PO4or “LMFP”), lithium nickel manganese cobalt oxide (i.e., LiNixMnyCo1-x-yO2or “NMC”), lithium nickel cobalt aluminum oxide (i.e., LiNixCoyAlzO2 or “NCA”), lithium manganese oxide (“LMO”), lithium nickel manganese oxide (“LNMO”), lithium cobalt oxide (“LCO”), lithium titanate (“LTO”), or combinations thereof. In some embodiments, the cathode active material includes at least two of LFP, LMFP, NMC, NCA, LMO, LNMO, LCO, LTO, and combinations thereof. In some embodiments, the cathode active material is an iron phosphate-based active material. In some embodiments, iron phosphate-based active materials include LiFePO4(i.e., “lithium iron phosphate” and “LFP”) and LiMn1-xFexPO4(i.e., “lithium manganese iron phosphate” and “LMFP”) (e.g., LiMn0.6Fe0.4PO4or LiMn0.8Fe0.2PO4). In some embodiments, the iron phosphate-based active material includes LFP. In some embodiments, the iron phosphate- based active material includes an LMFP. In some embodiments, the iron phosphate-based active material includes an LFP and / or an LMFP. In some embodiments, the cathode active material is a polycrystal, a single crystal, or combinations thereof.

[0062] In some embodiments, the active material is an anode active material. In some embodiments, anode active materials can include, for example, an insertion material (such as carbon, graphite, and / or graphene), an alloying / dealloying material (such as silicon, silicon oxide, tin, and / or tin oxide), a metal alloy or compound (such as Si-Al, and / or Si-Sn), and / or a conversion material (such as manganese oxide, molybdenum oxide, nickel oxide, and / or copper oxide). The anode active materials can be used alone or mixed together to form multi-phase materials (such as Si-C, Sn-C, SiOx-C, SnOx-C, Si-Sn, Si-SiOx, Sn-SnOx, Si- SiOx-C, Sn-SnOx-C, Si-Sn-C, SiOx-SnOx-C, Si-SiOx-Sn, or Sn-SiOx-SnOx.). Anode active materials include common natural graphite, synthetic or artificial graphite, surface-modified graphite, spherical-shaped graphite, flake-shaped graphite and blends or combinations of thesetypes of graphite, metallic elements and their compounds as well as metal-C composite for anode.

[0063] In some embodiments, the electrode film mixture and / or electrode film comprises the active material in an amount of, of about, of at least, or at least about, 70 wt.%, 75 wt.%, 80 wt.%, 85 wt.%, 86 wt.%, 87 wt.%, 88 wt.%, 89 wt.%, 90 wt.%, 91 wt.%, 92 wt.%, 93 wt.%, 94 wt.%, 95 wt.%, 96 wt.%, 97 wt.%, 98 wt.%, 98.5 wt.%, 99 wt.%, 99.5 wt.%, 99.8 wt.% or 99.9 wt.%, or any range of values therebetween.

[0064] In some embodiments, an electrode film mixture and / or an electrode film comprises a carbon material configured to reversibly intercalate lithium ions. In some embodiments, the lithium intercalating carbon is selected from a graphitic carbon, graphite, hard carbon, soft carbon and combinations thereof. For example, the electrode film of the electrode can include a binder material, one or more of graphitic carbon, graphite, graphene- containing carbon, hard carbon and soft carbon, and an electrical conductivity promoting material. In some embodiments, an electrode is mixed with lithium metal and / or lithium ions. In some embodiments, the electrode comprises the carbon material in a total amount of, of about, of at most, or at most about, 20 wt.%, 15 wt.%, 10 wt.%, 9 wt.%, 8 wt.%, 7 wt.%, 6 wt.%, 5 wt.%, 4 wt.%, 3 wt.%, 2 wt.%, 1 wt.%, or any range of values therebetween.

[0065] In some embodiments, an electrode film mixture and / or an electrode film includes a conductive additive. In some embodiments, the conductive additive may comprise a conductive carbon additive, such as a carbon black. In some embodiments, the conductive additive may comprise a conductive carbon additive. In some embodiments, the conductive carbon additive comprises carbon black, carbon nanotubes, such as single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). In some embodiments, the electrode film comprises the conductive additive in a total amount of, of about, of at most, or at most about, 10 wt.%, 9 wt.%, 8 wt.%, 7 wt.%, 6 wt.%, 5 wt.%, 4 wt.%, 3 wt.%, 2 wt.%, 1 wt.%, 0.5 wt.%, 0.25 wt.%, 0.1 wt.%, or any range of values therebetween. In some embodiments, each of the conductive additives is in an amount of, of about, of at most, or at most about, 10 wt.%, 9 wt.%, 8 wt.%, 7 wt.%, 6 wt.%, 5 wt.%, 4 wt.%, 3 wt.%, 2 wt.%, 1 wt.%, 0.5 wt.%, 0.25 wt.%, 0.1 wt.%, of the electrode film, or any range of values therebetween. In some embodiments, the conductive additive is carbon black.

[0066] In some embodiments, the electrode film mixture and / or the electrode film includes a binder. In some embodiments, binders can include polytetrafluoroethylene (PTFE), a polyolefin, polyalkylenes, polyethers, styrene-butadiene, co-polymers of polysiloxanes and polysiloxane, branched polyethers, polyvinylethers, a carboxymethylcellulose (CMC), co- polymers thereof, and / or combinations thereof. In some embodiments, the polyolefin can include polyethylene (PE), polypropylene (PP), polyvinylidene fluoride (PVDF), co-polymers thereof, and / or combinations thereof. For example, the binder can include polyvinylene chloride, poly(phenylene oxide) (PPO), polyethylene-block-poly(ethylene glycol), poly(ethylene oxide) (PEO), poly(phenylene oxide) (PPO), polyethylene-block-poly(ethylene glycol), polydimethylsiloxane (PDMS), polydimethylsiloxane-coalkylmethylsiloxane, co- polymers thereof, and / or combinations thereof. In some embodiments, the binder may include a thermoplastic. In some embodiments, the binder comprises a fibrillizable and / or fibrillized polymer. In certain embodiments, the binder comprises, consists essentially, or consists of a single fibrillizable and / or fibrillized binder, such as PTFE. In some embodiments, the electrode film includes, includes about, includes at most, or includes at most about, 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.%, 10 wt.%, or any range of values therebetween, of a binder.

[0067] In some embodiments, the electrode film can be a wet processed electrode film. In some embodiments, the electrode film is prepared by a wet or slurry-based electrode fabrication process. In some embodiments, the electrode film of the present disclosure can be a dry processed electrode film. In some embodiments, the electrode film is prepared by a dry electrode fabrication process. As used herein, a dry electrode fabrication process can refer to a process in which no or substantially no solvents are used to form a dry electrode film. For example, components of the active layer or electrode film, including carbon materials and binders, may comprise, consist of, or consist essentially of dry particles. The dry particles for forming the active layer or electrode film may be combined to provide a dry particle active layer mixture. In some embodiments, the active layer or electrode film may be formed from the dry particle active layer mixture such that weight percentages of the components of the active layer or electrode film and weight percentages of the components of the dry particle active layer mixture are substantially the same. In some embodiments, the active layer or electrode film formed from the dry particle active layer mixture using the dry fabricationprocess may be free from, or substantially free from, any processing additives such as solvents and solvent residues resulting therefrom. In some embodiments, the resulting active layer or electrode films are self-supporting films formed using the dry process from the dry particle mixture. In some embodiments, the resulting active layer or electrode films are free-standing films formed using the dry process from the dry particle mixture. A process for forming an active layer or electrode film can include fibrillizing the fibrillizable binder component(s) such that the film comprises fibrillized binder. In further embodiments, a free-standing active layer or electrode film may be formed in the absence of a current collector. In still further embodiments, an active layer or electrode film may comprise a fibrillized polymer matrix such that the film is self-supporting. It is thought that a matrix, lattice, or web of fibrils can be formed to provide mechanical structure to the electrode film.

[0068] In some embodiments, an electrode film is disposed on a current collector to form an electrode. In some embodiments, a current collector can include a metallic material, such as a material comprising aluminum, nickel, copper, or combinations of the foregoing. In some embodiments, a current collector comprises a pure metal. In some embodiments, a current collector comprises a metallized polymer film or metal coated polymer film. In some embodiments, the polymer comprises polyethylene terephthalate (PET), biaxially oriented polypropylene (BOPP) or a combination thereof. In some embodiments, the metal coating comprises aluminum. In some embodiments, coating the final electrode film mixture comprises forming a uniform electrode film mixture coating. In some embodiments, the current collector comprises a thickness of, of about, of at most, or at most about, 200 μm, 100 μm, 50 μm, 40 μm, 30 μm, 20 μm, 15 μm, 10 μm, 5 μm, or any range of values therebetween.

[0069] An energy storage system or device includes a positive electrode (i.e., cathode), a negative electrode (i.e., anode), a separator disposed therebetween, and an electrolyte positioned within a housing. Each electrode includes an electrode film disposed over a current collector. The electrode includes an electrode film disposed over a current collector. In some embodiments, the current collector is a foil. In some embodiments, the current collector is aluminum foil, a copper foil, or combinations thereof. In some embodiments, a current collector can include a metallic material, such as a material comprising aluminum, nickel, copper, or combinations of the foregoing. In some embodiments, a current collector comprises a pure metal. In some embodiments, a current collector comprises ametallized polymer film or metal coated polymer film. In some embodiments, the polymer comprises polyethylene terephthalate (PET), biaxially oriented polypropylene (BOPP) or a combination thereof. In some embodiments, the metal coating comprises aluminum. In some embodiments, coating the final electrode film mixture comprises forming a uniform electrode film mixture coating. In some embodiments, the current collector comprises a thickness of, of about, of at most, or at most about, 200 μm, 100 μm, 50 μm, 40 μm, 30 μm, 20 μm, 15 μm, 10 μm, 5 μm, or any range of values therebetween. In some embodiments, an active layer is disposed on each side of the current collector.

[0070] In some embodiments, an electrode is a double-sided electrode. In some embodiments, the double-sided electrode includes two electrode films. In some embodiments, the double-sided electrode may include a current collector, a top electrode film, and a bottom electrode film. In some embodiments, each of the two electrode films can have any suitable shape, size and thickness.

[0071] In some embodiments, the energy storage device comprises a separator, an anode electrode, a cathode electrode, an electrolyte, and a housing, wherein the electrolyte, separator, anode electrode and cathode electrode are disposed within the housing and the separator is positioned between the anode and cathode electrodes. In some embodiments, an energy storage device is formed by placing an electrolyte, a separator, an anode electrode and the cathode electrode described herein within a housing, wherein the separator is placed between the anode electrode and the cathode electrode.

[0072] An electrode assembly includes a cathode, an anode, and a separator positioned between the anode and cathode. In some embodiments, the electrode assembly is a wound electrode (i.e., rolled electrode) assembly (e.g., a jelly roll). In some embodiments, the energy storage device is selected from the group consisting of a cylindrical energy storage device, a stacked prismatic energy storage device, and a spiral-wound prismatic energy storage device.

[0073] The normalized circularity may be used to determine and / or correlate to a relatively weak core spot (e.g., a spot that may cause electrode buckling) in the wound electrode assembly. Normalized circularity for a nonideal spiral is defined as the minimum ratio between the nonideal (real) geometry versus ideal geometry on a point-by-point basis according to the equation below.

[0074] The nonideal (real) spiral geometry is given by measured Cartesian andpolar coordinates , , , and the ideal spiral geometry is derived from an Archimedeanspiral according to . The geometry of a spiral (ideal or nonideal) can becharacterized by curvature , such as the polar curvature parameterization below.

[0075] In some embodiments, the electrode assembly comprises a normalized circularity value of, of about, of at least, or of at least about, 0.7, 0.705, 0.71, 0.715, 0.72, 0.725, 0.73, 0.735, 0.74, 0.745, 0.75, 0.76, 0.77, 0.78, 0.79, 0.8, 0.805, 0.81, 0.815, 0.82, 0.825, 0.83, 0.835, 0.84, 0.845, 0.85, 0.86, 0.87, 0.88, 0.89, 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, 1, 1.05, 1.1, 1.15, 1.2 or any range of values therebetween.

[0076] In some embodiments, the electrode assembly comprises a stiffness of, of about, of at least, or of at least about, 0.1 GPa, 0.2 GPa, 0.3 GPa, 0.4 GPa, 0.5 GPa, 0.6 GPa, 0.7 GPa, 0.8 GPa, 0.9 GPa, 1 GPa, 1.1 GPa, 1.2 GPa, 1.3 GPa, 1.4 GPa, 1.5 GPa, 1.6 GPa, 1.7 GPa, 1.8 GPa, 1.9 GPa, 2.0 GPa, 2.1 GPa, 2.2 GPa, 2.3 GPa, 2.4 GPa, 2.5 GPa, 2.6 GPa, 2.7 GPa, 2.8 GPa, 2.9 GPa, 3 GPa, 3.1 GPa, 3.2 GPa, 3.3 GPa, 3.4 GPa, 3.5 GPa, 3.6 GPa, 3.7 GPa, 3.8 GPa, 3.9 GPa, 4 GPa, or any range of values therebetween. In some embodiments, the electrode assembly comprises a stiffness of about 0.1 GPa to 1.5 GPa or any range of values therebetween.

[0077] The electrode (e.g., cathode, anode) disclosed herein may be used for an energy storage device. In some embodiments, the energy storage device comprises a separator, an anode electrode, a cathode electrode, an electrolyte, and a housing, wherein the electrolyte, separator, anode electrode and cathode electrode are disposed within the housing and the separator is positioned between the anode and cathode electrodes. In some embodiments, an energy storage device is formed by placing an electrolyte, a separator, an anode electrode and the cathode electrode described herein within a housing, wherein the separator is placed between the anode electrode and the cathode electrode. In some embodiments, the energy storage device comprises an anode electrode positioned between two cathode electrodes. Insome embodiments, the anode electrode and / or the cathode electrode comprises a shaped electrode film. In some embodiments, the energy storage device is a lithium-ion battery. In some embodiments, the energy storage devices may be a battery, capacitor, capacitor-battery hybrid, fuel cell, or combinations thereof. In some embodiments, the energy storage system or energy storage device may be used for electromobility. In some embodiments, the energy storage device may be used in motor vehicles, including hybrid electric vehicles (HEV), plug- in hybrid electric vehicles (PHEV), and / or electric vehicles (EV). In some embodiments, the energy storage device used in motor vehicles, including hybrid electric vehicles (HEV), plug- in hybrid electric vehicles (PHEV), and / or electric vehicles (EV) reduces greenhouse gas emissions.

[0078] In some embodiments, the energy storage device is charged with a suitable lithium-containing electrolyte. For example, the energy storage device can include a lithium salt, and a solvent, such as a non-aqueous or organic solvent. Generally, the lithium salt includes an anion that is redox stable. In some embodiments, the anion can be monovalent. In some embodiments, a lithium salt can be selected from lithium hexafluorophosphate (LiPF6), lithium bis(trifluoromethanesulfonyl)imide (LiFSI), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium bis(trifluoromethansulfonyl)imide (LiN(SO2CF3)2), lithium trifluoromethansulfonate (LiSO3CF3), lithium bis(oxalato)borate (LiB(C2O4)2), lithium bis(fluorosulfonyl)imide (LiN(SO2F)2, lithium difluoro(oxalato)borate (LiC2BF2O4) and combinations thereof. In some embodiments, the electrolyte can include a quaternary ammonium cation and an anion selected from the group consisting of hexafluorophosphate, tetrafluoroborate and iodide. In some embodiments, the salt concentration can be about 0.1 mol / L (M) to about 5 M, about 0.2 M to about 3 M, or about 0.3 M to about 2 M. In further embodiments, the salt concentration of the electrolyte can be about 0.7 M to about 2 M. In certain embodiments, the salt concentration of the electrolyte can be about 0.2 M, about 0.3 M, about 0.4 M, about 0.5 M, about 0.6 M, about 0.7 M, about 0.8 M. about 0.9 M, about 1 M, about 1.1 M, about 1.2 M, 1.3M, 1.4M, 1.5M or values therebetween. In some embodiments, salts are utilized as additives in the electrolyte system, and can be used at individual or total concentration of, of about, of at most, or at most about, 0.1 wt.%, 0.2 wt.%, 0.3 wt.%, 0.4 wt.%, 0.5 wt.%, 0.6 wt.%, 0.7 wt.%, 0.8 wt.%, 0.9 wt.%, 1 wt.%, 1.1 wt.%, 1.2 wt.%, 1.3 wt.%, 1.4 wt.%, 1.5 wt.%, 1.6 wt.%, 1.7 wt.%, 1.8 wt.%, 1.9 wt.%, 2 wt.%, 2.1 wt.%, 2.2 wt.%, 2.3 wt.%,2.4 wt.%, 2.5 wt.%, 2.6 wt.%, 2.7 wt.%, 2.8 wt.%, 2.9 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, 8 wt.%, 9 wt.% or 10 wt.%, or any range of values therebetween.

[0079] In some embodiments, an energy storage device can include a liquid solvent. The solvent need not dissolve every component, and need not completely dissolve any component, of the electrolyte. In further embodiments, the solvent can be an organic solvent. In some embodiments, a solvent can include one or more functional groups selected from dioxathiolane (e.g., 1,3,2-dioxathiolane-2,2-dioxide (i.e., “DTD”)), carbonates, ethers and / or esters. In some embodiments, the solvent can comprise a carbonate. In further embodiments, the carbonate can be selected from cyclic carbonates such as, for example, ethylene carbonate (EC), propylene carbonate (PC), vinyl ethylene carbonate (VEC), vinylene carbonate (VC), fluoroethylene carbonate (FEC), and combinations thereof, or acyclic carbonates such as, for example, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), 1,3-propene sultone (PRS), and combinations thereof. In some embodiments, the solvent can comprise an ester. In some embodiments, the ester is selected from methyl acetate (MA), methyl propionate (MP), ethyl acetate (EA), methyl butyrate (MB), and combinations thereof. In some embodiments, the solvent may include EC, PC, VEC, VC, FEC, DMC, DEC, EMC, MA, MP, EA, MB, and combinations thereof. In some embodiments, the solvent may include EC, DMC, DEC, EMC, MA, and combinations thereof. In some embodiments, the solvent may include EC, DMC, EMC, and combinations thereof. In some embodiments, the solvent may include a ratio of EC:DMC:EMC of 10-30:0-90:0-70.

[0080] In some embodiments, one or more solvents can be used at a concentration of, of about, of at least, or at least about, 15 wt.%, 20 wt.%, 30 wt. %, 35 wt. %, 40 wt. %, 45 wt. %, 50 wt. %, 55 wt. %, 60 wt. %, 65 wt. %, 70 wt. %, 75 wt. %, 80 wt. %, 85 wt. % or 90 wt. %, or any range of values therebetween. In some embodiments, solvents are utilized as additives in the electrolyte system, and can be used at a concentration of, of about, of at most, or at most about, 0.1 wt. %, 0.2 wt. %, 0.3 wt. %, 0.4 wt. %, 0.5 wt. %, 0.6 wt. %, 0.7 wt. %, 0.8 wt. %, 0.9 wt. %, 1 wt. %, 1.1 wt. %, 1.2 wt. %, 1.3 wt. %, 1.4 wt. %, 1.5 wt. %, 1.6 wt. %, 1.7 wt. %, 1.8 wt. %, 1.9 wt. %, 2 wt. %, 2.1 wt. %, 2.2 wt. %, 2.3 wt. %, 2.4 wt. %, 2.5 wt. %, 2.6 wt. %, 2.7 wt. %, 2.8 wt. %, 2.9 wt. %, 3 wt. %, 4 wt. %, 5 wt. %, 6 wt. %, 7 wt. %, 8 wt. %, 9 wt. % or 10 wt. %, or any range of values therebetween. For example, in some embodiments, the amount of an additive in the electrolyte is or is about in any one of thefollowing ranges: 0.1-10 wt.%, 1-6 wt.%, 2-5 wt.%, 0.1-6 wt.%, 2-8 wt.%, 2-3 wt.%, or 1-4 wt.%.

[0081] In some embodiments, an energy storage device is created such that one electrode (e.g., anode) is larger than and overhangs the other electrode (e.g., cathode). One electrode may overhang the other in the winding direction and / or non-winding direction of the electrode assembly. Such electrode overhangs may avoid yield losses. In some embodiments where there is no, or is substantially no, overlap and / or intermingling of the separator and the shaped electrode film (e.g., cathode electrode film), the boundary of the shaped electrode film is easier to identify and therefore improves the ability to form a counter electrode (e.g., anode electrode) with an overhang. EXAMPLES

[0082] Support materials and / or electrically floating support inserts were tested in various electrolyte compositions, cycling potentials, half cells and full cells. The nominal electrolytes tested included LiFSi; about 4.5-9.5 wt.%, LiPF6: about 6.5-11 wt.%, EC: about 15-16 wt.%, DMC: about 53-59 wt.%, and EMC: about 0-4 wt.%. Example 1 - Coin Cell Results

[0083] Coin cells with a 316 stainless steel electrically floating support insert were formed, and FIG. 3 shows cycling voltages vs. corrosion current density for the stainless steel electrically floating support insert. The coin cells were operated by holding an open circuit for 5 minutes, polarizing to -0.2V vs. holding an open circuit potential then raising the potential by 1mV / s until reaching 4.5V or a current of 20mA, and performing a reverse scan to -0.2V vs. original open circuit potential at 1mV / s.

[0084] The stainless steel was stable when tied to an anode, as its open circuit potential is above the anode potential range. The stainless steel was active in the cathode potential window and may corrode if tied to cathode potentials. The stainless steel demonstrated a low corrosion current at open circuit, indicating it is kinetically stable under floating potential conditions. The open circuit potential is about 1.4 ± 0.5 V vs. Li / Li+, the corrosion current is about 1.4 ± 0.9 E-5 mA / cm2, and the pitting potential is about 3.94-4.1 ± 0.1 V vs. Li / Li+.Example 2 – Material Corrosion

[0085] FIGS. 4A-5B show the results from a soak test in a nominal electrolyte or an electrolyte with 500 ppm of water at 55°C of low carbon steel and 316 stainless steel. In the soak test, pitting was observed in low carbon steel after 3 days of soaking in nominal electrolyte, and low carbon steel discolored and corroded after 12 days exposure to a water spiked electrolyte. Pitting was not observed on stainless in nominal or the water spiked electrolyte.

[0086] FIGS.6A and 6B show a cyclic voltammetry (CV) scan of stainless steel vs Li from a voltage range of 0.1-4.5V. The stainless steel corroded significantly within cathode voltage range, however in the anode voltage range the stainless steel did not significantly corrode or otherwise react. These results demonstrate the stability window of the stainless steel in an electrolyte, and that if biasing of the electrically floating support insert toward the anode or cathode conditions occurs within an energy storage device due to electric fields within the cell, stainless steel shows wide window of operability on the cathode side and no substantial operability issues on the anode side. Example 3 – Pouch Cells

[0087] FIGS.7A-7C show the results of a pouch cell with 1 gram of a floating 316 stainless steel support insert sheet to conform with the pouch cell geometry. The pouch cell was cycled at a C / 10 rate, 240 mAh and 0.6 mL of an electrolyte. FIGS. 7A-7C demonstrate that no significant capacity degradation or hysteresis increase over about 17 cycles at a C / 10 charge / discharge rate. Furthermore, the potential of the stainless steel was shown to stabilize at about 2 V or about 2.67 V vs graphite anode. No significant pitting or corrosion was seen on the surface of stainless steel insert. Example 4 – Jar Cells

[0088] Jar cells were formed for cycling the voltages, metals and measuring current densities, where a jar was assembled in a glovebox, filled with an electrolyte, lithium metal and a test metal were electrically connected to feedthrough wires and added to the electrolyte, and the jar was sealed before a voltage was applied.Formation Cycle

[0089] FIGS. 8A and 8B show jar cell results of simulated formation total coulombic efficiencies and formation total charge consumptions for electrically floating support insert made from copper, 304 stainless steel (304 SS), 430 stainless steel (430 SS), or Nickel. All metal charge consumptions were calculated against the same surface area. Each metal was cycled from open circuit voltage at a rate of 1 mV / s to between 0 and 1.25V vs. Li / Li+ for three cycles after initially being polarized to +0.2V to measure floating corrosion currents. The 0V to 1.25V bounds represent the cycling limits of supercharging and severe cell discharge over three cycles, which is more aggressive than typical formation cycling protocols.

[0090] All tested metals had low charge consumptions during formation, representing <0.01% of cell capacity (25.65Ah cell). The 304 SS and pure nickel charge consumptions and coulombic efficiencies are similar to that of copper during simulated formation cycling. The 430 stainless steel demonstrated similar charge consumption relative to the other tested metals despite lower coulombic efficiency. Cathode Cycling

[0091] FIGS.9A-9E showing voltage vs. current densities of various metals tested in jar cells. Nickel demonstrated a similar open circuit potential (OCP) of about 3.0 V compared to stainless steels and is known to be stable when tied to anode potentials. The OCP of nickel did not reliably increase after a single corrosion sweep, suggesting that only weak passivation may occur in nickel after one cathode side cycle. Nickel has a passivation breakdown at 3.95V Nickel’s corrosion current density in the electrolyte is 4x10-4mA / cm2, and is expected to have similar stability as stainless steels under floating potential conditions.

[0092] Both 304 and 316 stainless steels demonstrated open circuit potentials greater than 2.5V and are expected to be stable when tied to anode potentials. The 316 stainless steel OCP was about 2.9V, while the 304 stainless steel OCP was about 2.8V. The OCP of the stainless steels increased after a single corrosion sweep, suggesting that the stainless steels become more passive after one cathode side cycle. Both stainless steels also have low opencircuit corrosion current densities at 2x10-4mA / cm2, exhibit passivation breakdowns above 4.0V and are expected to be more stable than copper under floating potential conditions.

[0093] 430 stainless steel is still expected to be stable when tied to anode potentials with an OCP greater than 2.0V, as the 430 stainless steel OCP was 2.6V. The OCP of 430 stainless steel increases after a single corrosion sweep, suggesting that the stainless steels become more passive after one cathode side cycle. The 430 stainless steel showed a corrosion current density of 3x10-5mA / cm2, but is not expected to be substantively different in performance from 316 and 304 under floating conditions.430 stainless steel has a passivation breakdown at 3.23V, indicating little passivity under cathode conditions in the first cycle.

[0094] 1010 low carbon steel is expected to be stable when tied to anode potentials with an OCP of greater than 2.5V, as the 1010 low carbon steel showed an OCP of about 2.9V. The OCP of 1010 low carbon steel only marginally increases after a single corrosion sweep, suggesting that carbon steels do not become more passive after one cathode side cycle. The corrosion current density of 1010 low carbon steel is 1x10-3mA / cm2, and is expected to have a stability between copper and stainless steel under floating potential conditions. 1010 low carbon steel has a passivation breakdown in some tests at 3.45V while others do not exhibit significant passivation, indicating little passivity under cathode conditions in the first cycle.

[0095] Copper’s corrosion current density in electrolyte was about 10-2mA / cm2. Metal Floating Potential Corrosion Resistance

[0096] FIGS.10A and 10B show jar cell corrosion resistance kinetics of aluminum, copper and nickel-plated steel (NPS) in a nominal electrolyte, wherein aluminum was shown to have the highest corrosion resistance, NPS with a corrosion resistance below that of aluminum, and copper with a corrosion resistance below that of NPS.

[0097] Copper was shown to corrode whenever exposed to cathode potentials or to hydrofluoric acid (HF), and continued to corrode as long as either condition is present in the cell. Copper did not have any polarization resistance or stability window in electrolyte, did not become more passive over time, and spontaneously corroded. Aluminum was the most stable metal at the floating potential measured. Aluminum is also expected to have improved resistance to trace HF. As such, although aluminum did not demonstrate significant stability at anode potentials, a floating aluminum support insert may be the most resistant metal choice.The nickel-plated steel results may be more representative of iron’s stability than nickel’s given abundant surface defects. Pure nickel may also have a wide stability window and is known to be stable at anode potentials, as demonstrated in FIGS.9A.

[0098] Table 1 summarizes the open circuit potentials of copper, NPS and aluminum in a nominal electrolyte. Table 1Metal Stability Over Time

[0099] FIG. 11 shows jar cell metal stability testing at open circuit potential of aluminum, copper and nickel plated steel (NPS) in a nominal electrolyte. No clear delayed reactions or other changes in open circuit potential were observed from aluminum or copper testing over 45 minutes in nominal electrolyte. As no additional passive films are expected to form from electrolyte exposure, further changes in open circuit potential are not expected for longer soak times. Example 5 – Hydrofluoric Acid Dosed Electrolyte

[0100] FIGS. 12A and 12B show ICP-MS measurements of copper dissolution in an electrolyte including 0 ppm (“nominal electrolyte”), 200 ppm or 400 ppm of hydrofluoric acid (“HF”) at 25°C or 55°C. FIGS.13A-13C corrosion test of copper samples with a nominal electrolyte, 200 ppm HF or 400 ppm HF after ten days at 55°C. Copper dissolution was shown to be more strongly related to soak time and / or temperature than HF content as changes in HF concentration did not have a significant impact in dissolution. As such, copper does not seem to be stable in electrolyte solutions with HF at a floating potentials.

[0101] FIGS. 14A-14D corrosion test of aluminum samples with a nominal electrolyte, 200 ppm HF or 400 ppm HF after two or ten days at 55°C, where mild corrosionwas seen in samples without HF, pitting was seen in samples with HF. HF content did not appear to influence the amount of corrosion. Example 1-5 Summary

[0102] Table 2 summarizes the results of Examples 1-5. 316 stainless steel (“SS”) and aluminum are suitable and 304 SS and nickel are likely suitable for use as support materials for floating support inserts, while copper and carbon steels are not suitable. Trace HF or moisture (i.e., water) are significant corrosion sources in the electrolyte, with passivation likely occurring in stainless steels and nickel over time while copper is unstable in nominal electrolyte and continues to corrode over time.

[0103] Floating corrosion currents for all three stainless steel grades and pure nickel in nominal electrolyte are similar to or lower than copper. Soaking testing indicated copper spontaneously corrodes while at floating potential for longer periods, while 316 SS does not corrode even after exposure to 500 ppm HF. All stainless steels and nickel have passive regions and are therefore expected to have superior resistance to trace HF than copper. All three stainless steels partially passivate after one cathode potential cycle, with higher open circuit potentials after a single cycle. Table 2

[0104] While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosure. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the systems and methods described herein may be made without departing from the spirit of the disclosure. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosure.

[0105] Features, materials, characteristics, or groups described in conjunction with a particular aspect, embodiment, or example are to be understood to be applicable to any other aspect, embodiment or example described in this section or elsewhere in this specification unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The protection is not restricted to the details of any foregoing embodiments. The protection extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0106] Furthermore, certain features that are described in this disclosure in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations, one or more features from a claimed combination can, in some cases, be excised from the combination, and the combination may be claimed as a subcombination or variation of a subcombination.

[0107] Moreover, while operations may be depicted in the drawings or described in the specification in a particular order, such operations need not be performed in the particular order shown or in sequential order, or that all operations be performed, to achieve desirable results. Other operations that are not depicted or described can be incorporated in the example methods and processes. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the described operations. Further, the operations may be rearranged or reordered in other implementations. Those skilled in the art will appreciate that in some embodiments, the actual steps taken in the processes illustrated and / or disclosed may differ from those shown in the figures. Depending on the embodiment, certain of the steps described above may be removed, others may be added. Furthermore, the features and attributes of the specific embodiments disclosed above may be combined in different ways to form additional embodiments, all of which fall within the scope of the present disclosure. Also, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described components and systems can generally be integrated together in a single product or packaged into multiple products. For example, any of the components for an energy storage system described herein can be provided separately, or integrated together (e.g., packaged together, or attached together) to form an energy storage system.

[0108] For purposes of this disclosure, certain aspects, advantages, and novel features are described herein. Not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, for example, those skilled in the art will recognize that the disclosure may be embodied or carried out in a manner that achieves one advantage or a group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.

[0109] Conditional language, such as “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements, and / or steps. Thus, such conditional language is not generally intended to imply that features, elements, and / or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with orwithout user input or prompting, whether these features, elements, and / or steps are included or are to be performed in any particular embodiment.

[0110] Conjunctive language such as the phrase “at least one of X, Y, and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be either X, Y, or Z. Thus, such conjunctive language is not generally intended to imply that certain embodiments require the presence of at least one of X, at least one of Y, and at least one of Z.

[0111] Language of degree used herein, such as the terms “approximately,” “about,” “generally,” and “substantially” as used herein represent a value, amount, or characteristic close to the stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms “approximately,” “about,” “generally,” and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of the stated amount, depending on the desired function or desired result.

[0112] The scope of the present disclosure is not intended to be limited by the specific disclosures of preferred embodiments in this section or elsewhere in this specification, and may be defined by claims as presented in this section or elsewhere in this specification or as presented in the future. The language of the claims is to be interpreted broadly based on the language employed in the claims and not limited to the examples described in the present specification or during the prosecution of the application, which examples are to be construed as non-exclusive.

[0113] The headings provided herein, if any, are for convenience only and do not necessarily affect the scope or meaning of the devices and methods disclosed herein.

Claims

WHAT IS CLAIMED IS:

1. A wound electrode assembly, comprising: a cathode; an anode; a separator positioned between the anode and cathode, wherein the cathode, the anode and the separator are wound about a central axis to form an inner diameter surface surrounding a cylindrical void; and a floating support insert positioned within the cylindrical void, wherein the floating support insert comprises a conductive support material, and wherein the floating support insert is electrically insulated from each of the anode and the cathode.

2. The wound electrode assembly of Claim 1, wherein the conductive support material is selected from the group consisting of a stainless steel, aluminum, nickel, and combinations thereof.

3. The wound electrode assembly of Claim 1 or 2, wherein the floating support insert further comprises a coating material.

4. The wound electrode assembly of Claim 3, wherein the coating material is selected from the group consisting of a nickel plated coating, a chrome plated coating, a metal cladding, a stainless steel coating, a low carbon steel coating, a copper coating, an aluminum coating, a polymer coating, and combinations thereof.

5. The wound electrode assembly of any one of Claims 1-4, wherein the floating support insert has an open circuit potential (OCP) vs. Li / Li+of about 2.5 V to about 4 V.

6. The wound electrode assembly of Claim 5, wherein the floating support insert has a corrosion current density in a service potential range above OCP to 4.0 V vs. Li / Li+of about 0.1 mA / cm2to about 1.1 mA / cm2.

7. The wound electrode assembly of Claim 5, wherein the floating support insert has a vs. Li / Li+pitting potential of about 3.5 V to about 5 V.

8. The wound electrode assembly of any one of Claims 1-7, wherein the floating support insert is substantially corrosion resistant under soaking in an electrolyte containing 500 ppm HF at 55°C for about 10-20 days.

9. The wound electrode assembly of any one of Claims 1-8, wherein the floating support insert further comprises an intervening insulating material coating.

10. An energy storage device, comprising the wound electrode assembly of any one of Claims 1-9, an electrolyte and a housing, wherein the wound electrode assembly and the electrolyte are positioned within the housing.

11. The energy storage device of Claim 10, wherein the floating support insert has no substantive electrochemical reaction with lithium in a service potential range below OCP to 0 V vs. Li / Li+.

12. The energy storage device of Claim 10 or 11, wherein the floating support insert has a current density between OCP and 0.005 V vs. Li / Li+of about 0.05 mA / cm2to about 0.6 mA / cm2.

13. The energy storage device of any one of Claims 10-12, wherein the floating support insert has a charge consumption when cycled between 0.0 V and 1.25 V vs. Li / Li+three times starting from OCP for cycle 0 of about 0.5 mAh / cm2to about 3.5 mAh / cm2.

14. A method of forming a wound electrode assembly, comprising: positioning a separator between an anode and a cathode to form an electrode assembly, winding the separator, the cathode, the anode about a central axis to form an inner diameter surface of the electrode assembly surrounding a cylindrical void; and positioning a floating support insert within the cylindrical void of the electrode assembly after winding to form a wound electrode assembly.

15. The method of Claim 14, further comprising disposing an intervening insulating material coating over the floating support insert.

16. The method of Claim 15, wherein positioning the floating support insert within the cylindrical void of the electrode assembly comprises physically contacting the floating support insert with the cathode and the anode.

17. The method of Claim 14, wherein positioning the floating support insert within the cylindrical void of the electrode assembly comprises avoiding physically contacting the floating support insert with the cathode and the anode.

18. The method of Claim 14, wherein positioning the floating support insert within the cylindrical void of the electrode assembly comprises utilizing an insertion device to position the floating support insert within the cylindrical void.

19. The method of any one of Claims 14-18, wherein the inner diameter surface of the electrode assembly is processed prior to insertion of the floating support insert.

20. A method of forming an energy storage device, comprising: disposing the wound electrode assembly according to the method of any one of Claims 14-19 and an electrolyte within a housing to form the energy storage device.

21. The method of Claim 20, further comprising positioning the floating support insert within the cylindrical void after disposing the wound electrode assembly within the housing.

22. The method of Claim 20, further comprising positioning the floating support insert within the cylindrical void before disposing the wound electrode assembly within the housing.

23. The method of Claim 20, further comprising positioning the floating support insert within the cylindrical void concurrently with disposing the wound electrode assembly within the housing.

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