Tapered electrode and method

Abstract

This disclosure relates to a tapered electrode architecture and a method for fabricating the same. Energy storage devices, such as lithium-ion batteries, that utilize the tapered electrode architecture are also described.

Description

[Technical Field]

[0001] [Cross-reference of related applications] This application claims the benefit of U.S. Provisional Application No. 63 / 580,901, filed on 6 September 2023, the full disclosure thereof is incorporated herein by reference in its entirety.

[0002] This disclosure relates to energy storage devices and methods for fabricating the same. More specifically, this disclosure relates to electrode architectures and methods for fabricating and using the same. [Background technology]

[0003] Currently, many types of battery cells are used as energy sources in electric vehicles and energy storage applications. Many current cells use a jelly roll design in which the cathode, anode, and separator are wound together and have cathode tabs and anode tabs for connecting to the positive and negative terminals of the cell can.

[0004] Energy storage devices are susceptible to mechanical failures of components that can lead to cell and / or product failure. In some cases, electrode edges and / or corners concentrate mechanical stress, which can be exacerbated by reversible and irreversible electrode volume expansion, or swelling due to charging and cell degradation. Such mechanical stress concentrations can lead to mechanical failures of components, such as mechanical failures of separators (e.g., wear, overload, fatigue, creep, etc.), which can cause internal short circuits. Therefore, minimizing such stresses in energy storage devices can be advantageous. [Overview of the project] [Means for solving the problem]

[0005] For the purpose of summarizing the advantages achieved beyond this disclosure and the prior art, specific purposes and advantages of this disclosure are described herein. Not all such purposes or advantages can be achieved in any particular embodiment. Therefore, for example, a person skilled in the art will recognize that the present invention may be embodied or implemented to achieve or optimize one or more advantages as taught herein, without necessarily achieving other purposes or advantages as taught or suggested herein.

[0006] All of these embodiments are intended to be within the scope of the invention disclosed herein. These and other embodiments will be readily apparent to those skilled in the art from the following detailed description of preferred embodiments with reference to the accompanying drawings, and the invention is not limited to any specific preferred embodiment(s) disclosed.

[0007] In one embodiment, an electrode is described. The electrode includes a foil, an active material layer disposed on a first surface of the foil, and a first portion and a tapered portion, wherein the tapered portion includes a tapered distal end and a tapered proximal end adjacent to the first portion, the active material layer in the first portion includes a first thickness, and the active material layer in the tapered portion includes a tapered thickness less than the first thickness, decreasing in thickness from the tapered proximal end to the tapered distal end. In some embodiments, the tapered portion includes a taper gradient of about 0.1 to 20°. In some embodiments, the tapered portion includes a taper gradient of about 0.1 to 45°. In some embodiments, the length of the tapered portion from the tapered proximal end to the tapered distal end is about 1 to 10 mm. In some embodiments, the length of the tapered portion from the tapered proximal end to the tapered distal end is about 0.1 to 60 mm.

[0008] In some embodiments, the electrode further includes a plateau portion comprising a distal plateau end and a proximal plateau end adjacent to the tapered distal end. In some embodiments, the length of the plateau portion from the proximal plateau end to the distal plateau end is approximately 0.1 to 10 mm. In some embodiments, the length of the plateau portion from the proximal plateau end to the distal plateau end is approximately 0.1 to 20 mm. In some embodiments, the foil includes a distal foil end, and the distal plateau end substantially overlaps with the distal foil end.

[0009] In some embodiments, the foil includes a distal end, and the tapered distal end substantially overlaps the distal end. In some embodiments, the electrode further includes an exposed portion with an exposed distal end and an exposed proximal end, and the active material layer is not located on the exposed portion. In some embodiments, the exposed proximal end is adjacent to the tapered distal end. In some embodiments, the exposed proximal end is adjacent to the plateau distal end.

[0010] In some embodiments, the electrode further includes a second active material layer disposed on a second surface of the foil. In some embodiments, the electrode further includes a second tapered portion including a second tapered distal end and a second tapered proximal end. In some embodiments, the electrode further includes a second plateau portion including a second plateau distal end and a second plateau proximal end. In some embodiments, the electrode is a cathode. In some embodiments, the electrode further includes a tape or coating, the tape or coating disposed on at least one of the first portion, the tapered portion, the plateau portion, or the exposed portion. In some embodiments, the electrode further includes at least one of the tape and the coating, the tape or coating disposed on at least one of the first portion, the tapered portion, the plateau portion, and the exposed portion.

[0011] In other embodiments, energy storage devices are described. In some embodiments, the energy storage device comprises electrodes, electrolytes, and housings as described herein, wherein the electrodes and electrolytes are located within the housings. In some embodiments, the energy storage device comprises electrodes, a second electrode, a separator positioned between the electrodes and the second electrode, an electrolyte, and housings as described herein, wherein the electrodes, the second electrode, the separator, and the electrolytes are located within the housings. In some embodiments, the energy storage device is selected from the group consisting of cylindrical energy storage devices, stacked prismatic energy storage devices, and helically wound prismatic energy storage devices. In some embodiments, tapered portions substantially prevent the formation of collisions within the electrodes. In some embodiments, tapered portions substantially prevent the formation of collisions between the electrodes and at least one of the separator and the second electrode.

[0012] In another embodiment, a method for manufacturing an electrode is described. In some embodiments, the method includes arranging a first active material portion on a first portion of a foil, wherein the first active material portion includes a first thickness, and arranging a tapered active material portion on a second portion of the foil, wherein the tapered active material portion includes a tapered distal end and a tapered proximal end adjacent to the first active material portion, and the tapered active material portion includes a tapered thickness that decreases from the tapered proximal end to the tapered distal end. In some embodiments, the method further includes drying the first active material portion and the tapered active material portion to form an active material film. [Brief explanation of the drawing]

[0013] [Figure 1A] This figure shows the end of an unfolded jelly roll, with the anode electrode extending over the cathode electrode, according to one embodiment.

[0014] [Figure 1B]It is a diagram showing the end of an expanded jelly roll according to one embodiment, in which the anode electrode overhangs the cathode electrode and the anode current collector extends beyond the anode coating.

[0015] [Figure 2] It is a horizontal cross-sectional X-ray computed tomography (CT) image of a wound jelly roll having an overhang.

[0016] [Figure 3A] It is a cross-sectional view of stress concentration and collision points near the end of the jelly roll.

[0017] [Figure 3B] It is a horizontal cross-sectional CT image of stress concentration and collision points near the end of the jelly roll.

[0018] [Figure 4] It is a horizontal cross-sectional CT image of a jelly roll having an existing collision region.

[0019] [Figure 5A] It is a horizontal cross-sectional CT image of a cell having an anode tab and a cathode tab including an existing collision region and an internal jelly roll.

[0020] [Figure 5B] It is a vertical cross-sectional view of the cell and the internal jelly roll shown in FIG. 5A.

[0021] [Figure 6A] It is another horizontal cross-sectional CT image of a cell having an anode tab and a cathode tab including an existing collision region and an internal jelly roll.

[0022] [Figure 6B] It is a vertical cross-sectional view of the cell and the internal jelly roll shown in FIG. 6A.

[0023] [Figure 7] It is a side view of a tapered electrode according to one embodiment.

[0024] [Figure 8] This is a side view of a tapered electrode according to one embodiment.

[0025] [Figure 9] This is a side view of a tapered electrode according to one embodiment.

[0026] [Figure 10] This is a side view of a tapered electrode according to one embodiment.

[0027] [Figure 11] This is a side view of an electrode wrapped with tapered tape, according to one embodiment.

[0028] [Figure 12] This is a side view of a tapered coated electrode according to one embodiment.

[0029] [Figure 13A] This is a side view of the coating pattern of a tapered electrode according to one embodiment.

[0030] [Figure 13B] This is a side view of different tapered electrode coating patterns according to one embodiment.

[0031] [Figure 14] This is a side view of the coating pattern of a tapered coated electrode according to one embodiment.

[0032] [Figure 15] This is a graph showing the thickness of the active material coating deposited on the foil versus time in a coating pattern of a tapered electrode according to one embodiment.

[0033] [Figure 16A] This is a horizontal cross-sectional CT image of a cell having a tapered electrode and an external anode tab, and an internal jelly roll, according to one embodiment.

[0034] [Figure 16B] Figure 16A shows a vertical cross-sectional view of the jelly roll.

[0035] [Figure 17A] This is a simulated horizontal cross-sectional view of a jelly roll showing 6% anode swelling.

[0036] [Figure 17B] This is a simulated horizontal cross-sectional view of a jelly roll showing 12% anode swelling.

[0037] [Figure 17C] This is a simulated horizontal cross-sectional view of a jelly roll showing 18% anode swelling.

[0038] [Figure 18A] This is a simulated horizontal cross-sectional view of a jelly roll having a tapered cathode electrode according to one embodiment, showing 6% anode swelling.

[0039] [Figure 18B] This is a simulated horizontal cross-sectional view of a jelly roll having a tapered cathode electrode according to one embodiment, showing 12% anode swelling.

[0040] [Figure 18C] This is a simulated horizontal cross-sectional view of a jelly roll having a tapered cathode electrode according to one embodiment, showing 18% anode swelling.

[0041] [Figure 19A] This is a simulated horizontal cross-sectional view of a jelly roll.

[0042] [Figure 19B] This is a simulated horizontal cross-sectional view of a jelly roll having a tapered cathode electrode with a taper depth of 20% according to one embodiment.

[0043] [Figure 19C] This is a simulated horizontal cross-sectional view of a jelly roll having a tapered cathode electrode with a 45% taper depth, according to one embodiment.

[0044] [Figure 19D] This is a simulated horizontal cross-sectional view of a jelly roll having a tapered cathode electrode with a 70% taper depth, according to one embodiment.

[0045] [Figure 20A] This is a simulated horizontal cross-sectional view of a jelly roll similar to Figure 19A, showing 14% anode swelling.

[0046] [Figure 20B] This is a simulated horizontal cross-sectional view of a jelly roll having a tapered cathode electrode, as shown in Figure 19B, exhibiting 14% anode swelling.

[0047] [Figure 20C] This is a simulated horizontal cross-sectional view of a jelly roll having a tapered cathode electrode, as shown in Figure 19C, exhibiting 14% anode swelling.

[0048] [Figure 20D] This is a simulated horizontal cross-sectional view of a jelly roll having a tapered cathode electrode, as shown in Figure 19D, exhibiting 14% anode swelling.

[0049] [Figure 21A] Figure 19A is a simulated horizontal cross-sectional view of the jelly roll, showing 20% ​​anode swelling.

[0050] [Figure 21B] This is a simulated horizontal cross-sectional view of a jelly roll having a tapered cathode electrode, as shown in Figure 19B, exhibiting 20% ​​anode swelling.

[0051] [Figure 21C] This is a simulated horizontal cross-sectional view of a jelly roll having a tapered cathode electrode, as shown in Figure 19C, exhibiting 20% ​​anode swelling.

[0052] [Figure 21D] This is a simulated horizontal cross-sectional view of a jelly roll having a tapered cathode electrode, as shown in Figure 19D, exhibiting 20% ​​anode swelling.

[0053] [Figure 22A] This is a simulated horizontal cross-sectional view showing the anode bending angle within the jelly roll.

[0054] [Figure 22B] This is a graph of the calculated anode bending angle within simulated jelly rolls with various anode swelling rates and taper depths.

[0055] [Figure 23A] This is a simulated horizontal cross-sectional view showing separator stress within a jelly roll.

[0056] [Figure 23B] This is a graph of normalized separator stress calculated within simulated jelly rolls with various taper depths.

[0057] [Figure 24A] The images show horizontal cross-sectional CT images of experimental cells with tapered cathodes before and after cycling, according to several embodiments.

[0058] [Figure 24B] Figure 24A shows magnified horizontal cross-sectional CT images of experimental cells with tapered cathodes before and after each cycle, according to several embodiments, and of a control, corresponding to each image shown. [Modes for carrying out the invention]

[0059] This disclosure can be understood by referring to the following detailed description. For clarity, it should be noted that certain elements of the various drawings may not be drawn to scale, may be represented schematically or conceptually, and may not otherwise precisely correspond to the specific physical configuration of the embodiment.

[0060] This disclosure relates to a tapered electrode used in an energy storage device, wherein the tapered electrode includes a tapered portion, and the active material within the tapered portion has a tapered thickness. In some embodiments, a tapered electrode having a tapered portion can help reduce stress on components within an energy storage device, thereby preventing separator failure and / or internal short circuits. In some embodiments, the tapered portion substantially prevents the formation of collisions within the energy storage device. In some embodiments, the electrode of this disclosure includes a foil, an active material layer disposed on a first surface of the foil, and a first portion and a tapered portion, wherein the tapered portion includes a tapered distal end and a tapered proximal end adjacent to the first portion, the active material layer within the first portion includes a first thickness, and the active material layer within the tapered portion includes a tapered thickness less than the first thickness, with the thickness decreasing from the tapered proximal end to the tapered distal end.

[0061] In some embodiments, the end of the unfolded jelly roll includes an anode and a cathode, with an anode overhang portion, where the cathode is not positioned above the anode overhang portion. For example, Figure 1A shows the end of an unfolded jelly roll 100 having an anode electrode 104, an anode tab 102, a cathode electrode 108, and an anode electrode edge 106 extending a distance 112 from the cathode electrode edge 110. In another example, Figure 1B shows the end of an unfolded jelly roll 120 having an anode electrode 122 and a cathode electrode 124. The anode electrode 122 includes an anode electrode film 126, an anode electrode film edge 128 at the mechanically distal end of the anode electrode film 126, and an anode current collector 130 extending distally beyond the anode electrode film edge 128. The cathode electrode 124 includes a cathode electrode edge 132 at the mechanically distal end of the cathode electrode 124, the anode electrode 122 extends laterally on both sides of the cathode electrode 124, and the anode electrode film 126 extends onto the cathode electrode 124 by a distance 134 measured from the anode electrode film edge 128 to the cathode electrode edge 132.

[0062] Such anode overhangs remain when the jelly roll is wound so that the end of the anode overhang does not adjoin the end of the cathode. For example, Figure 2 is a horizontal cross-sectional image of a wound jelly roll with an overhang. However, if the active material layer placed on the cathode foil terminates abruptly, it can cause stress concentration points within the jelly roll and its components (e.g., on the anode electrode), which can worsen with aging from cell charging and use. Figure 3A shows the location of the wound jelly roll region 300 at the cathode end and the stress concentration point 302A, and Figure 3B is an image of an exemplary cell with such a stress concentration point 302B. The wound jelly roll region 300 includes the cathode end 304 located between the internal separator layer 306A and the external separator layer 306B, all of which are located between the internal anode layer 308A and the external anode layer 308B. It is understood that the internal anode layer 308A and the external anode layer 308B are in different positions along the same anode length when wound onto a jelly roll. The internal separator layer 306A and the external separator layer 306B are different, distinct separators. The cathode is a bifacial electrode such that the cathode end 304 includes a cathode current collector 310 located between the upper cathode film 312 and the lower cathode film 314. Similarly, the anode is a bifacial electrode such that the internal anode layer 308A and the external anode layer 308B include an anode current collector 316 located between the upper anode film 318 and the lower anode film 320. As shown in Figure 3A, the overhang of the internal anode layer 308A beyond the cathode end 304 causes the internal anode layer 308A and the internal separator layer 306A to curve, deviating from the typical helical curvature of the jelly roll, and such a stress concentration point 302A is formed behind the cathode end 304.

[0063] Stress points within the jelly roll and its components (e.g., electrodes) can cause anode collision regions and / or local buckling regions, ultimately leading to internal short circuits (due to mechanical failure of the separator), followed by cell and / or product failure. Figure 4 is a horizontal cross-sectional image of a jelly roll with an existing collision region. Figure 5A is a horizontal cross-sectional image of jelly roll 500 including an existing collision region, and Figure 5B is a vertical cross-sectional image of jelly roll 500. Figure 6A is another horizontal cross-sectional image of jelly roll 600 including an existing collision region, and Figure 6B is a vertical cross-sectional image of jelly roll 600.

[0064] Some embodiments of the present disclosure relate to an electrode comprising a foil, an active material layer disposed on a first surface of the foil, and a first portion and a tapered portion. In some embodiments, the tapered portion includes a tapered distal end and a tapered proximal end adjacent to the first portion. In some embodiments, the active material layer in the first portion includes a first thickness. In some embodiments, the active material layer in the tapered portion includes a tapered thickness less than the first thickness, with the thickness decreasing from the tapered proximal end to the tapered distal end.

[0065] In some embodiments, the foil includes a distal end, and the tapered distal end substantially overlaps with the distal end. As an example, Figure 7 is a side view of a double-sided tapered electrode 700. The tapered electrode 700 includes a current collector foil 701, an active material layer 702 disposed on a first surface of the foil, a first portion 703, a tapered portion 704, and a second active material layer 707 disposed on a second surface of the foil. The foil 701 includes a proximal end 708 and a distal end 709. The active material layer 702 in the first portion 703 has a first thickness. The active material layer 702 in the tapered portion 704 includes a tapered thickness smaller than the first thickness, decreasing in thickness from the tapered proximal end 704a to the tapered distal end 704b. The tapered distal end 704b overlaps with the distal end 709.

[0066] In some embodiments, the tapered electrode further includes a plateau portion comprising a distal plateau end and a proximal plateau end adjacent to the distal tapered end. As an example, Figure 8 is a side view of a double-sided tapered electrode 800. The tapered electrode 800 includes a current collector foil 801, an active material layer 802 disposed on a first surface of the foil, a first portion 803, a tapered portion 804, a plateau portion 805, and a second active material layer 807 disposed on a second surface of the foil. The foil 801 includes a proximal foil end 808 and a distal foil end 809. The active material layer 802 in the first portion 803 has a first thickness. The active material layer 802 in the tapered portion 804 includes a tapered thickness smaller than the first thickness, decreasing in thickness from the proximal tapered end 804a to the distal tapered end 804b. The plateau portion 805 includes the distal plateau end 805b and the proximal plateau end 805a adjacent to the distal tapered end 804b. The distal plateau end 805b overlaps with the distal foil end 809.

[0067] In some embodiments, the electrode further includes exposed portions, including an exposed distal end and an exposed proximal end, and the active material layer is not located on the exposed portions of the current collector. In some embodiments, the exposed proximal end is adjacent to the tapered distal end. As an example, Figure 9 is a side view of a double-sided tapered electrode 900. The tapered electrode 900 includes a current collector foil 901, an active material layer 902 located on a first surface of the foil, a first portion 903, a tapered portion 904, an exposed portion 906, and a second active material layer 907 located on a second surface of the foil. The foil 901 includes a foil proximal end 908 and a foil distal end 909. The active material layer 902 in the first portion 903 has a first thickness. The active material layer 902 in the tapered portion 904 includes a tapered thickness smaller than the first thickness, decreasing in thickness from the tapered proximal end 904a to the tapered distal end 904b. The exposed portion 906 includes an exposed distal end 906b and an exposed proximal end 906a, and the active material layer 902 is not located on the exposed portion 906. The exposed proximal end 906a is adjacent to the tapered distal end 904b.

[0068] In some embodiments, the exposed proximal end is adjacent to the plateau distal end. As an example, Figure 10 is a side view of a double-sided tapered electrode 1000. The tapered electrode 1000 includes a current collector foil 1001, an active material layer 1002 disposed on a first surface of the foil, a first portion 1003, a tapered portion 1004, a plateau portion 1005, an exposed portion 1006, and a second active material layer 1007 disposed on a second surface of the foil. The foil 1001 includes a foil proximal end 1008 and a foil distal end 1009. The active material layer 1002 in the first portion 1003 has a first thickness. The active material layer 1002 in the tapered portion 1004 includes a tapered thickness smaller than the first thickness, decreasing in thickness from the tapered proximal end 1004a to the tapered distal end 1004b. The plateau portion 1005 includes a plateau distal end 1005b and a plateau proximal end 1005a adjacent to the tapered distal end 1004b. The exposed portion 1006 includes an exposed distal end 1006b and an exposed proximal end 1006a, and the active material layer 1002 is not located above the exposed portion 1006. The exposed proximal end 1006a is adjacent to the plateau distal end 1005b.

[0069] In some embodiments, the electrode further includes a second active material layer disposed on a second surface of the foil. In some embodiments, the second active material layer includes the same or different tapered portions, plateau portions, and / or exposed portions as those of the first active material layer. In some embodiments, the electrode further includes a second plateau portion including a second plateau distal end and a second plateau proximal end. In some embodiments, the electrode further includes a second tapered portion including a second tapered distal end and a second tapered proximal end.

[0070] In some embodiments, the tapered electrode further includes a tape and / or coating. In some embodiments, the tape or coating is positioned over at least one of the first portion, the tapered portion, the plateau portion, or the exposed portion, or any combination thereof. As an example, Figure 11 is a side view of a tapered electrode 1102 having a tapered portion 1104 and an exposed portion 1106 extending beyond the tapered portion 1104, with the tape and / or coatings 1108A and 1108B positioned over the exposed portion 1106 and over at least a portion of the tapered portion 1104. Figure 12 is a side view of a tapered electrode 1202 having a tapered portion 1204 and an exposed portion 1206 extending beyond the tapered portion 1204, with the tape and / or coatings 1208A and 1208B positioned over the exposed portion 1106. In some embodiments, the tape and / or coating includes an insulating material (e.g., a ceramic material and / or a polymer material).

[0071] In some embodiments, the tapered portion is 0.1°, 0.2°, 0.3°, 0.4°, 0.5°, 0.6°, 0.7°, 0.8°, 0.9°, 1°, 1.1°, 1.2°, 1.3°, 1.4°, 1.5°, 1.6°, 1.7°, 1.8°, 1.9°, 2°, 2.1°, 2.2°, 2.3°, 2.4°, 2.5°, 2.6°, 2.7°, 2.8°, 2.9°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12° , including taper gradients of approximately these, at least these, or at least approximately these, in the range of any values ​​between them, such as 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34°, 35°, 36°, 37°, 38°, 39°, 40°, 41°, 42°, 43°, 44°, or 45°, or any range of values ​​between them. In some embodiments, the length of the tapered portion from the proximal end to the distal end of the tapered portion is 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, or 60 mm, or any range of values ​​between them, approximately these, at least these, or at least approximately these.In some embodiments, the length of the plateau portion from the proximal end to the distal end of the plateau is 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, 3 mm, 3.1 mm, 3.2 mm, 3.3 mm, 3.4 mm, 3.5 mm, 3.6 mm, 3.7 mm, 3 0.8mm, 3.9mm, 4mm, 4.1mm, 4.2mm, 4.3mm, 4.4mm, 4.5mm, 4.6mm, 4.7mm, 4.8mm, 4.9mm, 5mm, 5.1mm, 5.2mm, 5.3mm, 5.4mm, 5.5mm, 5.6mm, 5.7mm, 5.8mm, 5.9mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, or 20mm, or any range of values ​​between them, approximately these, at least these, or at least approximately these.

[0072] [Energy storage devices] The electrodes disclosed herein can be used in energy storage devices, for example, in electric vehicles. In some embodiments, the energy storage device comprises one or more separators, an anode electrode, a cathode electrode, an electrolyte, and a housing, wherein the electrolyte, separator, anode electrode, and cathode electrode are arranged within the housing, and the separator is positioned between the anode electrode and the cathode electrode. In some embodiments, the energy storage device is formed by placing the electrolyte, separator, anode electrode, and cathode electrode described herein within the housing, and the separator is positioned between the anode electrode and the cathode electrode. In some embodiments, the energy storage device is a battery. In some embodiments, the energy storage device is a lithium-ion battery. In some embodiments, the energy storage device comprises an anode electrode positioned between two cathode electrodes.

[0073] In some embodiments, the electrode film is free of or substantially free of solvent residue. In some embodiments, the electrode film contains about 90% by weight, 91% by weight, 92% by weight, 93% by weight, 94% by weight, 95% by weight, 96% by weight, 97% by weight, 98% by weight, or 99% by weight, or any range of values ​​in between, of these active materials, at least these, or at least about these.

[0074] In some embodiments, the active material is a cathode active material, an anode active material, or a combination thereof. In some embodiments, the cathode active material is selected from at least one of metal oxides, metal sulfides, sulfur-carbon composites, lithium metal oxides, and materials containing sulfur. In some embodiments, the cathode active material is lithium iron phosphate (i.e., LiFePO4 or "LFP"), lithium iron manganese phosphate (e.g., LiMn 0.6 Fe 0.4 PO4 or "LMFP"), lithium nickel manganese cobalt oxide (i.e., LiNi x Mn y Co 1-x-y O2 or "NMC"), lithium nickel cobalt aluminum oxide (i.e., LiNi x Co y Al zO2 or "NCA"), lithium manganese oxide ("LMO"), lithium nickel manganese oxide ("LNMO"), lithium cobalt oxide ("LCO"), lithium titanate ("LTO"), or a combination thereof. In some embodiments, the cathode active material comprises at least two of LFP, LMFP, NMC, NCA, LMO, LNMO, LCO, LTO, and combinations thereof. In some embodiments, the cathode active material can comprise, for example, a metal oxide, a metal sulfide, or a lithium metal oxide. The lithium metal oxide can be, for example, lithium nickel manganese cobalt oxide (NMC), lithium manganese oxide (LMO), lithium iron phosphate (LFP), lithium cobalt oxide (LCO), lithium titanate (LTO), and / or lithium nickel cobalt aluminum oxide (NCA). In some embodiments, the cathode active material is, for example, a layered transition metal oxide (LiCoO2 (LCO), Li(NiMnCo)O2 (NMC) and / or LiNi 0.8 Co 0.15 Al 0.05 O2 (NCA), etc.), spinel-type manganese oxide (LiMn2O4 (LMO) and / or LiMn 1.5 Ni 0.5 O4 (LMNO), etc.), olivine (such as LiFePO4), chalcogenide (LiTiS2), tavorite (LiFeSO4F), silicon, silicon oxide (SiOx), aluminum, tin, tin oxide (SnOx), manganese oxide (MnOx), molybdenum oxide (MoO2), molybdenum disulfide (MoS2), nickel oxide (NiOx), and copper oxide (CuOx), or a combination thereof. The cathode active material can comprise sulfur, a sulfur-containing material such as lithium sulfide (Li2S), another sulfur-based material, or a mixture thereof.

[0075] In some embodiments, the anode active material may include, for example, insert materials (such as carbon, graphite, and / or graphene), alloying / dealloying materials (such as silicon, silicon oxide, tin, and / or tin oxide), metallic alloys or compounds (such as Si-Al and / or Si-Sn), and / or conversion materials (such as manganese oxide, molybdenum oxide, nickel oxide, and / or copper oxide). The anode active material may be used alone or mixed together to form a multiphase material (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 graphite, flake graphite, and blends or combinations of these types of graphite, metal elements and their compounds, and metal-C composites for anodes.

[0076] In some embodiments, the electrode film contains about these, at most these, or at most these binders in a range of 1% by weight, 2% by weight, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight, 10% by weight, or any value in between. In some embodiments, the electrode film contains about these, at most these, or at most these binders in a range of 1% by weight, 2% by weight, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight, 10% by weight, or any value in between. In some embodiments, the electrode film contains about these, at most these, or at most these binders in a range of 1% by weight, 2% by weight, 3% by weight, 4% by weight, or 5% by weight, or any value in between. In some embodiments, the binder (e.g., fluorinated binder, low surface energy binder) is selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl fluoride (PVF), polychlorotrifluoroethylene (PCTFE), perfluoroalkoxy polymer (PFA), fluorinated ethylene propylene (FEP), polyethylene tetrafluoroethylene (ETFE), polyethylene chlorotrifluoroethylene (ECTFE), perfluorinated elastomer, fluoroelastomer, perfluoropolyether (PFPE), polyethylene (PE), polypropylene (PP), poly(ethylene oxide) (PEO), poly(phenylene oxide) (PPO), polyethylene-block-poly(ethylene glycol), polydimethylsiloxane (PDMS), polydimethylsiloxane-coalkylmethylsiloxane, carboxymethylcellulose (CMC), copolymers thereof, and combinations thereof.In some embodiments, the binder (e.g., fluorinated binder, low surface energy binder) is selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl fluoride (PVF), polychlorotrifluoroethylene (PCTFE), perfluoroalkoxy polymer (PFA), fluorinated ethylene propylene (FEP), polyethylene tetrafluoroethylene (ETFE), polyethylene chlorotrifluoroethylene (ECTFE), perfluorinated elastomer, fluoroelastomer, perfluoropolyether (PFPE), copolymers thereof, and combinations thereof. In some embodiments, the electrode film contains about these, at most these, or at most about these binders in amounts of 0.1% by weight, 0.5% by weight, 1% by weight, 2% by weight, 3% by weight, 5% by weight, 8% by weight, 10% by weight, 15% by weight, 20% by weight, 25% by weight, 30% by weight, 40% by weight, 50% by weight, 60% by weight, or 70% by weight, or any range of values ​​in between.

[0077] In some embodiments, the electrode film comprises a carbon material configured to reversibly intercalate lithium ions. In some embodiments, the electrode film comprises a total amount of carbon material in a range of 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 value in between, approximately these, at most these, or at most approximately these. In some embodiments, the carbon intercalating lithium is selected from graphitic carbon, graphite, hard carbon, soft carbon, and combinations thereof. For example, the electrode film of an electrode may include a binder material, one or more of graphitic carbon, graphite, graphene-containing carbon, hard carbon, and soft carbon, and a conductivity-enhancing material. In some embodiments, the electrode is mixed with lithium metal and / or lithium ions.

[0078] In some embodiments, the electrode film includes a conductive additive. In some embodiments, the conductive additive may include a conductive carbon additive. In some embodiments, the conductive carbon additive includes carbon black, carbon nanotubes, such as single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). In some embodiments, the electrode film includes the conductive additive in a total amount of about these, at most these, or at most about these, in a range of values ​​of 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 value in between. In some embodiments, each of the conductive additives is in an amount of 10% by weight, 9% by weight, 8% by weight, 7% by weight, 6% by weight, 5% by weight, 4% by weight, 3% by weight, 2% by weight, 1% by weight, 0.5% by weight, 0.25% by weight, 0.1% by weight, or any range of values ​​in between, of the electrode film, at most these, or at most about these amounts. In some embodiments, the conductive additive is carbon black.

[0079] In some embodiments, the electrode film includes thicknesses of approximately these, at most these, or at most these, in the range of 1000 μm, 900 μm, 800 μm, 700 μm, 600 μm, 500 μm, 400 μm, 300 μm, 250 μm, 200 μm, 150 μm, 100 μm, 90 μm, 80 μm, 70 μm, 60 μm, 50 μm, 40 μm, 30 μm, 20 μm, 15 μm, 10 μm, or any range of values ​​in between. In some embodiments, the electrode film is 3 mg / cm² 2 , 4 mg / cm³ 2 , 5 mg / cm³ 2 , 10 mg / cm³ 2 , 15 mg / cm³ 2 , 20 mg / cm³ 2 , 30 mg / cm³ 2 , 40 mg / cm³ 2 , 50 mg / cm³ 2 , 100 mg / cm³ 2It may provide an active material load (which can be expressed as the mass of the electrode film per unit area of ​​the electrode film or current collector) of about these, at least these, or any range of values ​​between them.

[0080] In some embodiments, the electrode film may be a wet-processed electrode film. In some embodiments, the electrode film is prepared by a wet or slurry-based electrode manufacturing process. In some embodiments, the electrode film of this disclosure may be a dry-processed electrode film. In some embodiments, the electrode film is prepared by a dry electrode manufacturing process. As used herein, a dry electrode manufacturing process may refer to a process for forming a dry electrode film without the use of a solvent, or substantially without the use of a solvent. For example, the components of the active layer or electrode film, including a carbon material and a binder, may include, be composed of, or essentially consist of dry particles. A combination of dry particles for forming an active layer or electrode film can provide a dry particle active layer mixture. In some embodiments, the active layer or electrode film may be formed from a dry particle active layer mixture such that the weight percentages of the components of the active layer or electrode film and the weight percentages of the components of the dry particle active layer mixture are substantially the same. In some embodiments, an active layer or electrode film formed from a dry particle active layer mixture using a dry manufacturing process may not contain, or substantially contain, any processing additives such as solvents and the resulting solvent residues. In some embodiments, the resulting active layer or electrode film is a self-supporting film formed using a drying process from a dry particle mixture. In some embodiments, the resulting active layer or electrode film is an independent film formed using a drying process from a dry particle mixture. The process for forming the active layer or electrode film may include fibrillating a fibrillable binder component(s) such that the film contains a fibrillating binder. In further embodiments, the independent active layer or electrode film may be formed in the absence of a current collector. In further embodiments, the active layer or electrode film may contain a fibrillated polymer matrix such that the film is self-supporting. It is conceivable that a matrix, lattice, or web of fibrils can be formed to provide mechanical structure to the electrode film.

[0081] A “self-supporting” electrode film is an electrode film that incorporates a binder matrix structure sufficient to support the film or layer and maintain its shape so that the electrode film or layer can stand on its own. When incorporated into an energy storage device, a self-supporting electrode film or active layer incorporates such a binder matrix structure. Generally, and depending on the method of use, such an electrode film or active layer has sufficient strength for use in the energy storage device manufacturing process without external support elements such as current collectors or other films. For example, a “self-supporting” electrode film may have sufficient strength to be wound, handled, and unfolded in the electrode manufacturing process without other support elements. Dry electrode films, such as cathode electrode films or anode electrode films, may also be self-supporting.

[0082] In some embodiments, an electrode film is placed on a current collector to form an electrode. In some embodiments, the current collector may include a metallic material such as aluminum, nickel, copper, or a combination thereof. In some embodiments, the current collector may include a pure metal. In some embodiments, the current collector may include a metallized polymer film or a metal-coated polymer film. In some embodiments, the polymer may include polyethylene terephthalate (PET), biaxially oriented polypropylene (BOPP), or a combination thereof. In some embodiments, the metal coating may include aluminum. In some embodiments, coating the final electrode film mixture may involve forming a uniform electrode film mixture coating. In some embodiments, the current collector may include thicknesses of approximately these, at most these, or at most these, in the range of 200 μm, 100 μm, 50 μm, 40 μm, 30 μm, 20 μm, 15 μm, 10 μm, 5 μm, or any value in between.

[0083] In some embodiments, the 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, an upper electrode film, and a lower electrode film. In some embodiments, each of the two electrode films may have any preferred shape, size, and thickness.

[0084] In some embodiments, the energy storage device is filled with a suitable lithium-containing electrolyte. For example, the energy storage device may contain a lithium salt and a solvent such as a non-aqueous solvent or an organic solvent. Generally, the lithium salt contains a redox-stable anion. In some embodiments, the anion may be monovalent. In some embodiments, the lithium salt can be selected from lithium hexafluorophosphate (LiPF6), lithium bis(trifluoromethanesulfonyl)imide (LiFSI), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium bis(trifluoromethanesulfonyl)imide (LiN(SO2CF3)2), lithium trifluoromethanesulfonate (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 may include a quaternary ammonium cation and an anion selected from the group consisting of hexafluorophosphate, tetrafluoroborate, and iodide. In some embodiments, the salt concentration may 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 may be about 0.7 M to about 2 M. In certain embodiments, the salt concentration of the electrolyte may 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, 1.3 M, 1.4 M, 1.5 M, or values ​​in between.

[0085] In some embodiments, the energy storage device may contain a liquid solvent. The solvent does not need to dissolve all components of the electrolyte, nor does it need to completely dissolve any component. In further embodiments, the solvent may be an organic solvent. In some embodiments, the solvent may contain 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 may contain a carbonate. In further embodiments, the carbonate may be selected from cyclic carbonates, e.g., ethylene carbonate (EC), propylene carbonate (PC), vinylethylene carbonate (VEC), vinylene carbonate (VC), fluoroethylene carbonate (FEC), and combinations thereof, or acyclic carbonates, e.g., dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), and combinations thereof. In some embodiments, one or more solvents can be used in concentrations of 30% by weight, 35% by weight, 40% by weight, 45% by weight, 50% by weight, 55% by weight, 60% by weight, 65% by weight, 70% by weight, 75% by weight, 80% by weight, 85% by weight, or 90% by weight, or any range of values ​​in between, at least these, or at least about these concentrations. In some embodiments, the solvent is used as an additive in the electrolyte system and can be used in concentrations of approximately these, at most these, or at most these, in the range of values ​​of 0.1% by weight, 0.2% by weight, 0.3% by weight, 0.4% by weight, 0.5% by weight, 0.6% by weight, 0.7% by weight, 0.8% by weight, 0.9% by weight, 1% by weight, 1.1% by weight, 1.2% by weight, 1.3% by weight, 1.4% by weight, 1.5% by weight, 1.6% by weight, 1.7% by weight, 1.8% by weight, 1.9% by weight, 2% by weight, 2.1% by weight, 2.2% by weight, 2.3% by weight, 2.4% by weight, 2.5% by weight, 2.6% by weight, 2.7% by weight, 2.8% by weight, 2.9% by weight, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight, or 10% by weight, or any range of values ​​in between.For example, in some embodiments, the amount of additive in the electrolyte is one of the following ranges or about the following ranges: 0.1 to 10% by weight, 1 to 6% by weight, 2 to 5% by weight, 0.1 to 6% by weight, 2 to 8% by weight, 2 to 3% by weight, or 1 to 4% by weight.

[0086] 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 arranged within the housing, and the separator is positioned between the anode electrode and the cathode electrode. In some embodiments, the energy storage device is formed by installing the electrolyte, separator, anode electrode, and cathode electrode described herein within the housing, with the separator positioned between the anode electrode and the cathode electrode. In some embodiments, the energy storage device is a battery. In some embodiments, the energy storage device is a lithium-ion battery.

[0087] In some embodiments, the energy storage device may comprise one or more separators. In some embodiments, the one or more separators are in the form of laminates having a predetermined thickness, for example, in the range of 1 to 50 μm. In some embodiments, the one or more separators are in the range of about 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm, 30 μm, 40 μm, or 50 μm, or any value in between (e.g., 5 to 10 μm), at least these, or at least about these. Furthermore, in some embodiments, the one or more separators are electrically insulating. In some embodiments, the one or more separators may comprise a polymer material. In some embodiments, the one or more separators may be selected from polyethylene, polypropylene, or a combination thereof. In some embodiments, the one or more separators comprise multiple separator layers. In some embodiments, the one or more separators comprise micropores. In some embodiments, one or more separators operate at temperatures of approximately these, at most these, or at most these, within a range of values ​​of 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, or 30°C, or any range of values ​​in between. In some embodiments, one or more separators are bonded or bonded to the electrode film.

[0088] In some embodiments, the energy storage device comprises cell cores of approximately these, at most these, or at most these, in a range of values ​​of 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, or 12 mm, or any value in between.

[0089] In some embodiments, the energy storage device is selected from the group consisting of cylindrical energy storage devices, stacked rectangular energy storage devices, and helically wound rectangular energy storage devices. The energy storage devices provided herein may be any preferred configuration, e.g., planar, helically wound, button-shaped, or pouch-shaped. In some embodiments, the cathode, anode, and separator, which are arranged to overlap each other, are wound together to form a jelly roll design. In some embodiments, tapered portions substantially prevent the formation of collisions within the electrodes. Manufacturing method

[0090] Some embodiments of this disclosure relate to a process for preparing tapered electrodes disclosed herein. In some embodiments, a method for manufacturing an electrode includes placing an active material composition on a foil, wherein a first active material portion having a first thickness is placed on a first portion of the foil, and a tapered active material portion is placed on a second portion of the foil. In some embodiments, the tapered active material portion includes a tapered distal end and a tapered proximal end adjacent to the first active material portion. In some embodiments, the tapered active material portion includes a tapered thickness, decreasing in thickness from the tapered proximal end to the tapered distal end. In some embodiments, the tapered thickness is smaller than the first thickness. In some embodiments, placing the first active material composition further includes placing a plateau portion. In some embodiments, the plateau portion is adjacent to the tapered distal end. In certain embodiments, the process further includes stopping the placement of the first active material composition on the foil to form an exposed portion. In some embodiments, the exposed portion is adjacent to the tapered distal end or the plateau distal end. In some embodiments, the method for manufacturing an electrode further includes placing a second active material on a second surface of a foil. In some embodiments, the method further includes placing tabs on the foil. In certain embodiments, the method further includes drying the first active material composition to form an active material film. In certain embodiments, the first active material composition is an active material film.

[0091] In some embodiments, the method includes cutting the ends of the electrodes. As an example, Figure 13A is a side view of the coating pattern of a tapered electrode, where the lengths of portions A and B are similar, substantially the same, or the same. As another example, Figure 13B is a side view of the coating pattern of a tapered electrode, where the lengths of portions A and B are different or substantially different, such that the length of portion A is shorter than the length of portion B. In some embodiments, the lengths of portions A and B may be different or the same on both sides of the current collector foil. The electrodes shown in Figure 13A or Figure 13B are cut at the ends. In some embodiments, a tab is provided between portions A and B of the tapered electrode in Figure 13A and / or Figure 13B. In some embodiments, the method for manufacturing the electrode further includes adding tape to the ends of the electrodes. In some embodiments, the method for manufacturing the electrode further includes adding tape and / or coating to the ends of the electrodes. For example, Figure 14 is a side view of the coating pattern of a tapered coated electrode. Figure 15 is a graph showing the coating pattern of a tapered electrode, with respect to the thickness of the active material coating deposited on the foil versus time. [Examples]

[0092] The tapered electrode architecture of this disclosure can be prepared using the methods disclosed herein. Additional embodiments are disclosed in further detail in the following examples, but are not intended to limit the scope of the claims.

[0093] [Example 1 - Jelly roll with tapered electrodes] Figure 16A is a horizontal cross-sectional image of a cell having tapered cathode electrodes and its jelly roll 1600. The cell 1600 includes an anode tab 1603 and a cathode tab 1604 located closer to the center of the cell than the anode tab, as well as cathode electrodes tapered at ends 1601 and 1602.

[0094] Figure 16B is a vertical cross-sectional view of the cell and its jelly roll 1600, showing the uniform anode portion of the upper region 1605 and lower region 1606 of the electrode, compared to the upper region 601 and lower region 602 of the jelly roll 600 as depicted in Figure 6B.

[0095] [Example 2 - Swelling Simulation] Swelling simulations were performed for jelly rolls with and without tapered electrodes. For example, Figures 17A, 17B, and 17C are simulated horizontal cross-sectional views of jelly rolls without tapered cathode electrodes, showing 6%, 12%, and 18% anode swelling, respectively. Figures 18A, 18B, and 18C are simulated horizontal cross-sectional views of jelly rolls with tapered cathode electrodes, showing 6%, 12%, and 18% anode swelling, respectively. The modeled jelly roll without tapered electrodes showed visible collision at 6% swelling, as shown in Figure 17A, while the jelly roll with tapered cathode electrodes did not show visible collision at 18% anode swelling, as shown in Figure 18C.

[0096] [Example 3 - Finite Element Modeling] Finite element models were run for tapered electrodes with various taper depths. Figure 19A is a simulated horizontal cross-sectional view of a baseline jelly roll without a tapered cathode electrode. Figures 19B, 19C, and 19D are simulated horizontal cross-sectional views of jelly rolls with tapered cathode electrodes having taper depths of 20%, 45%, and 70%, respectively. Figure 20A is a simulated horizontal cross-sectional view of a jelly roll similar to Figure 19A, showing 14% anode swelling. Figures 20B, 20C, and 20D are simulated horizontal cross-sectional views of jelly rolls with tapered cathode electrodes as shown in Figures 19B, 19C, and 19D, showing 14% swelling, respectively. Figure 21A is a simulated horizontal cross-sectional view of a jelly roll similar to Figure 19A, showing 20% ​​swelling. Figures 21B, 21C, and 21D are simulated horizontal cross-sectional views of a jelly roll having a tapered cathode electrode as shown in Figures 19B, 19C, and 19D, respectively, showing 20% ​​swelling.

[0097] A modeled jelly roll without a tapered cathode electrode showed visible collision at 14% swelling, as shown in Figure 20A, while a jelly roll with a tapered cathode electrode having a 70% taper depth did not show visible collision at 20% swelling, as shown in Figure 21D.

[0098] [Example 4 - Anode Bending Angle Modeling] The anode bending angles were calculated in simulated jelly rolls with varying tapered depths and swelling rates, compared to a baseline jelly roll without a tapered cathode electrode. Figure 22A is a simulated horizontal cross-sectional view showing the model anode bending angles in the jelly roll. Figure 22B is a graph of the calculated bending angles in simulated jelly rolls with varying tapered depths and swelling rates.

[0099] As shown in Figure 22B, the anode bending angle decreases significantly as the taper depth ratio increases. For example, with simulated anode swelling of 15% or less, the anode bending angle of an anode with a taper depth of 20% shows a reduced anode bending angle compared to a baseline jelly roll without a tapered cathode electrode. Simulated jelly rolls with taper depths of 45% and 70% show a significantly reduced anode bending angle, even with 20% anode swelling, compared to a baseline jelly roll without a tapered cathode electrode.

[0100] [Example 5 - Separator Stress Modeling] Separator stresses were calculated for simulated jelly rolls with varying taper depths. Figure 23A is a simulated horizontal cross-sectional view showing the separator stress at a selected point within the jelly roll. Figure 23B is a graph of the normalized separator stress calculated within simulated jelly rolls with varying taper depths. As shown in Figure 23B, simulated jelly rolls with 45% and 70% taper depths show a significant reduction in separator stress compared to a baseline jelly roll without a tapered cathode electrode and a simulated jelly roll with a 20% taper depth.

[0101] [Example 6 - Cell Cycle Test] Figures 24A and 24B show horizontal cross-sectional CT images of an experimental cell with a tapered cathode and a control cell before and after cycling, demonstrating the effectiveness of tapered coating in preventing collisions. Two substantially identical cells were fabricated, one with a tapered cathode electrode (i.e., "tapered") and the other control cell without a tapered cathode electrode (i.e., "untapered"). Each cell was imaged by CT scan when newly constructed without cycling (i.e., "new") and after 100 charge and discharge cycles in which the jelly roll experienced significant swelling (i.e., "100 cycles"). As seen in Figures 24A and 24B, the untapered cell showed collisions after cycling, while the tapered cell did not.

[0102] While specific embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of this disclosure. In fact, the novel methods and systems described herein can be embodied in a variety of other forms. Furthermore, various omissions, substitutions, and modifications can be made in the systems and methods described herein without departing from the spirit of this disclosure. The appended claims and their equivalents are intended to encompass forms or modifications that are contained within the scope and spirit of this disclosure. Accordingly, the scope of the present invention is defined solely by reference to the appended claims.

[0103] Features, materials, properties, or groups described in relation to a particular aspect, embodiment, or example should be understood to be applicable to any other aspect, embodiment, or example described in this section or elsewhere in this specification, insofar as it does not conflict with such other aspects, embodiments, or examples. All features disclosed herein (including the appended claims, abstract, and drawings), and / or all steps of any method or process disclosed herein, may be combined in any combination, except for any combination in which at least some of such features and / or steps are mutually exclusive. Protection is not limited to the details of any of the aforementioned embodiments. Protection extends to any novel features or any novel combination of features disclosed herein (including the appended claims, abstract, and drawings), or any novel steps of any method or process disclosed herein.

[0104] Furthermore, certain features described in this disclosure in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented separately or in any preferred subcombination in multiple embodiments. Furthermore, features may be described above as acting in a particular combination, but one or more features from a claimed combination may, in some cases, be removed from the combination, and the combination may be claimed as a subcombination or a variation of a subcombination.

[0105] Furthermore, while operations may be shown in the drawings or described herein in a specific order, such operations do not need to be performed in the specific order shown or in a sequential order to achieve the desired result, nor do not all operations need to be performed. Other operations not shown or described may be incorporated into the exemplary methods and processes. For example, one or more additional operations may be performed before, after, simultaneously with, or between any of the described operations. Furthermore, operations may be rearranged or reordered in other embodiments. Those skilled in the art will understand that in some embodiments, the actual steps performed in the illustrated and / or disclosed processes may differ from those shown in the drawings. Depending on the embodiment, certain steps among the steps described above may be omitted, and other steps may be added. Furthermore, the features and attributes of the particular embodiments disclosed above may be combined in different ways to form additional embodiments, all of which are within the scope of this disclosure. Also, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and the described components and systems may generally be integrated together in a single product or packaged in multiple products. For example, any of the components of the energy storage system described herein may be provided separately or integrated (e.g., packaged together or mounted together) to form the energy storage system.

[0106] For the purposes of this disclosure, certain aspects, advantages, and novel features are described herein. Not all such advantages can necessarily be achieved according to any particular embodiment. Therefore, for example, a person skilled in the art will recognize that this disclosure may be embodied or implemented to achieve one or more advantages as taught herein, without necessarily achieving other advantages that can be taught or suggested herein.

[0107] Conditional language, such as "can," "could," "might," or "may," is generally intended to convey that a particular embodiment includes certain features, elements, and / or steps, but other embodiments do not, unless otherwise specified or understood in the context in which they are used. Therefore, such conditional language is generally not intended to suggest that features, elements, and / or steps are required in some way in one or more embodiments, or that one or more embodiments necessarily include logic for determining whether these features, elements, and / or steps should be included in or performed in any particular embodiment, with or without user input or prompting.

[0108] Conjunctional phrases such as "at least one of X, Y, and Z" are generally understood in contexts where they convey that an item, term, etc., could be any of X, Y, or Z, unless otherwise specified. Therefore, such conjunctional phrases are not generally intended to imply that a particular embodiment requires the presence of at least one X, at least one Y, and at least one Z.

[0109] As used herein, terms of degree such as “approximately,” “about,” “generally,” and “substantially” still represent values, quantities, or characteristics close to the stated values, quantities, or characteristics that still perform the desired function or achieve the desired result. For example, the terms “approximately,” “about,” “generally,” and “substantially” may refer to quantities within 10%, 5%, 1%, 0.1%, and 0.01% of the stated quantity, depending on the desired function or desired result.

[0110] The scope of this disclosure is not intended to be limited by any specific disclosure of preferred embodiments in this section or elsewhere in this specification, but may be defined by the claims, as presented in this section or elsewhere in this specification, or as presented in the future. The language of the claims should be interpreted broadly on the basis of the language used in the claims, and not limited to the examples described herein or during examination of the application, and the examples should be interpreted as non-exclusive.

Claims

1. Gold leaf and An active material layer disposed on the first surface of the foil, A first portion and a tapered portion, wherein the tapered portion includes a distal tapered end and a proximal tapered end adjacent to the first portion, The active material layer within the first portion includes a first thickness, The electrode comprises an active material layer within the tapered portion, which includes a tapered thickness smaller than the first thickness, with the thickness decreasing from the proximal end of the tapered portion to the distal end of the tapered portion.

2. The electrode according to claim 1, wherein the tapered portion includes a taper gradient of approximately 0.1 to 45°.

3. The electrode according to claim 1 or 2, wherein the length of the tapered portion from the proximal end to the distal end of the tapered portion is approximately 0.1 to 60 mm.

4. The electrode according to any one of claims 1 to 3, further comprising a plateau portion including a distal plateau end and a proximal plateau end adjacent to the distal tapered end.

5. The electrode according to claim 4, wherein the length of the plateau portion from the proximal end to the distal end of the plateau is approximately 0.1 to 20 mm.

6. The electrode according to any one of claims 4 or 5, wherein the foil includes a distal end and the plateau distal end substantially overlaps with the distal end of the foil.

7. The electrode according to any one of claims 1 to 3, wherein the foil includes a distal end and the tapered distal end substantially overlaps with the distal end of the foil.

8. The electrode according to any one of claims 1 to 6, wherein the electrode further includes an exposed portion including an exposed distal end and an exposed proximal end, and the active material layer is not disposed on the exposed portion.

9. The electrode according to claim 8, wherein the exposed proximal end is adjacent to the tapered distal end.

10. The electrode according to claim 8, wherein the exposed proximal end is adjacent to the plateau distal end.

11. The electrode according to any one of claims 1 to 10, further comprising a second active material layer disposed on the second surface of the foil.

12. The electrode according to any one of claims 1 to 11, further comprising a second tapered portion including a second tapered distal end and a second tapered proximal end.

13. The electrode according to any one of claims 1 to 12, further comprising a second plateau portion including a second plateau distal end and a second plateau proximal end.

14. The electrode according to any one of claims 1 to 13, wherein the electrode is a cathode.

15. The electrode according to any one of claims 1 to 14, further comprising at least one of a tape and a coating, wherein the tape or the coating is positioned on at least one of the first portion, the tapered portion, the plateau portion, and the exposed portion.

16. An energy storage device, An electrode according to any one of claims 1 to 15, The second electrode and A separator is placed between the electrode and the second electrode, Electrolytes, The casing and An energy storage device comprising the electrode, the second electrode, the separator, and the electrolyte, wherein the electrode, the second electrode, the separator, and the electrolyte are arranged within the housing.

17. The energy storage device according to claim 16, wherein the energy storage device is selected from the group consisting of a cylindrical energy storage device, a stacked rectangular energy storage device, and a helically wound rectangular energy storage device.

18. The energy storage device according to claim 16 or 17, wherein the tapered portion substantially prevents the formation of a collision between the electrode and at least one of the separator and the second electrode.

19. A method for manufacturing electrodes, A step of placing a first active material portion on a first portion of a foil, wherein the first active material portion includes a first thickness, The steps include placing a tapered active material portion on the second portion of the foil, Includes, The tapered active material portion includes a tapered distal end and a tapered proximal end adjacent to the first active material portion. A method wherein the tapered active material portion includes a tapered thickness such that the thickness decreases from the tapered proximal end to the tapered distal end.

20. The method according to claim 19, further comprising the step of drying the first active material portion and the tapered active material portion to form an active material film.

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