Cathode insulating coating

Abstract

Aspects of the present disclosure include cathodic insulating coating and coating overlay designs that utilize porous deposition of cathodic insulating coating material. An example vehicle includes an electric motor and a battery pack electrically coupled to the electric motor. The battery pack includes a plurality of battery cells. Each battery cell includes a cathode current collector having a cathode tab, a cathode active material interspersed over the cathode current collector, and a cathode insulating coating. A cathode insulating coating is formed directly on a portion of the cathode active material and directly on a portion of the cathode tab. The cathode insulating coating includes a porous macrostructure that is patterned such that a portion of the cathode active material underlying the cathode insulating coating is exposed, thereby providing a porous cathode insulating coating that prevents misalignment and sliding of the separator while reducing loss of ion transport dynamic characteristics.

Description

Technical Field

[0001] This disclosure relates to battery cell and electrode manufacturing and, more particularly, to cathode insulating coatings and coating overlap designs. Background Art

[0002] Electrodes are widely used in a range of devices for storing electrical energy, including primary (non-rechargeable) battery cells, secondary (rechargeable) battery cells, fuel cells, and capacitors. An ideal electrode needs to balance various electrical energy storage characteristics, such as energy density, power density, maximum charge rate, internal leakage current, equivalent series resistance (ESR), charge-discharge cycle durability, high electrical conductivity, and low tortuosity. Electrodes typically include a current collector to supplement or otherwise improve these electrical energy storage characteristics. A current collector can be added to provide higher specific conductance, and the available contact area can be increased to minimize the interfacial contact resistance between the electrode and its terminals.

[0003] A current collector is typically a sheet of conductive material to which an active electrode material is attached. Copper foil, aluminum foil, stainless steel, and titanium foil are commonly used as current collectors for electrodes. In a dry electrode manufacturing process, for example, a film containing activated carbon powder (e.g., an active electrode material) is attached to a thin aluminum foil using an adhesive layer. To improve the quality of the interfacial bond between the active electrode material film and the current collector, the combination of the film and the current collector is processed in a pressure laminator (e.g., a calender). This method is commonly referred to as calendering. Thus, in a dry manufacturing process, the fabrication of an electrode typically involves the production of an active electrode material film and the lamination of this film onto a current collector. Summary of the Invention

[0004] In one exemplary embodiment, a vehicle includes an electric motor and a battery pack electrically coupled to the electric motor. The battery pack includes a plurality of battery cells. Each battery cell includes a cathode current collector having a cathode tab, cathode active material dispersed on the cathode current collector, and a cathode insulating coating. The cathode insulating coating is formed directly on a portion of the cathode active material and directly on a portion of the cathode tab. The cathode insulating coating includes a porous macrostructure that is patterned such that portions of the cathode active material underlying the cathode insulating coating are exposed, thereby providing a porous cathode insulating coating that prevents misalignment and sliding of the separator while reducing loss of ionic transport kinetic properties.

[0005] In addition to one or more of the features described herein, in some embodiments, the porous macrostructure includes a micron-scale pattern. In some embodiments, the micron-scale pattern includes one or more lines having a line width of less than 15 microns.

[0006] In some embodiments, the cathode insulating coating includes one or more of a thermoplastic polymer, polyvinylidene fluoride (PVDF), polyethylene (PE), high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), polyacrylic acid, polyacrylate (PAA), anodic binder, styrene-butadiene rubber (SBR), carboxymethyl cellulose, and combinations thereof.

[0007] In some embodiments, the cathode insulating coating includes a porous material. The porous material may include one or more of polytetrafluoroethylene (PTFE), glass fiber, aerogel, cellulose-based insulating material, and combinations thereof.

[0008] In some embodiments, the cathode insulating coating extends to the edges of the cathode current collector and the cathode tab. In some embodiments, the cathode insulating coating extends at least 5 millimeters above the cathode active material.

[0009] In another exemplary embodiment, the battery cell includes a cathode current collector having a cathode tab, cathode active material dispersed on the cathode current collector, and a cathode insulating coating. The cathode insulating coating is formed directly on a portion of the cathode active material and directly on a portion of the cathode tab. The cathode insulating coating includes a porous macrostructure that is patterned such that some portions of the cathode active material underlying the cathode insulating coating are exposed, thereby providing a porous cathode insulating coating that prevents misalignment and sliding of the separator while reducing loss of ionic transport kinetics.

[0010] In some embodiments, the porous macrostructure includes a micron-scale pattern. In some embodiments, the micron-scale pattern includes one or more lines having a line width of less than 15 microns.

[0011] In some embodiments, the cathode insulating coating includes one or more of a thermoplastic polymer, polyvinylidene fluoride (PVDF), polyethylene (PE), high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), polyacrylic acid, polyacrylate (PAA), anodic binder, styrene-butadiene rubber (SBR), carboxymethyl cellulose, and combinations thereof.

[0012] In some embodiments, the cathode insulating coating includes a porous material. The porous material may include one or more of polytetrafluoroethylene (PTFE), glass fiber, aerogel, cellulose-based insulating material, and combinations thereof.

[0013] In some embodiments, the cathode insulating coating extends to the edges of the cathode current collector and the cathode tab. In some embodiments, the cathode insulating coating extends at least 5 millimeters above the cathode active material.

[0014] In yet another exemplary embodiment, the coating process may include providing a cathode current collector including a cathode tab, depositing a cathode active material on the cathode current collector, and forming a cathode insulating coating directly on a portion of the cathode active material and directly on a portion of the cathode tab. The cathode insulating coating includes a porous macrostructure that is patterned such that portions of the cathode active material underlying the cathode insulating coating are exposed, thereby providing a porous cathode insulating coating that prevents misalignment and slippage of the separator while reducing loss of ionic transport kinetic properties.

[0015] In some embodiments, the porous macrostructure includes a micron-scale pattern. In some embodiments, the micron-scale pattern includes one or more lines having a line width of less than 15 microns.

[0016] In some embodiments, the cathode insulating coating includes one or more of a thermoplastic polymer, polyvinylidene fluoride (PVDF), polyethylene (PE), high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), polyacrylic acid, polyacrylate (PAA), anodic binder, styrene butadiene rubber (SBR), carboxymethyl cellulose, and combinations thereof.

[0017] In some embodiments, the cathode insulating coating includes a porous material. The porous material may include one or more of polytetrafluoroethylene (PTFE), fiberglass, aerogel, cellulose-based insulating materials, and combinations thereof.

[0018] In some embodiments, the cathode insulating coating extends to the edges of the cathode current collector and the cathode tab. In some embodiments, the cathode insulating coating extends at least 5 millimeters above the cathode active material.

[0019] The above features and advantages of the present disclosure, as well as other features and advantages, are apparent from the following detailed description when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Other features, advantages, and details appear only by way of example in the following detailed description, which refers to the accompanying drawings.

[0021] Figure 1 is a vehicle configured according to one or more embodiments;

[0022] Figure 2A is an example battery cell according to one or more embodiments;

[0023] Figure 2B is according to one or more embodiments Figure 2A detailed view of the example battery cell shown in;

[0024] Figure 3 is an example that is part of a roll-to-roll coating process according to one or more embodiments;

[0025] Figure 4 is another example that is part of a roll-to-roll coating process according to one or more embodiments;

[0026] Figure 5A and 5B are example patterns of a porous cathode insulating coating according to one or more embodiments; and

[0027] Figure 6 is a flowchart according to one or more embodiments. Detailed Description

[0028] The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application, or uses. It should be understood that throughout the drawings, corresponding reference numerals represent the same or corresponding components and features.

[0029] Battery manufacturing, such as the production of a soft-packaged lithium-ion battery, involves the stacking of multiple electrically insulating electrodes. During this stacking process, the goal is to effectively arrange the multi-layer electrode materials, separators, and other components to form a structurally sound and electrically functional stack. In many manufacturing processes, the separator(s) is an insulating member located between adjacent battery components to prevent short circuits and ensure proper electrical insulation between the electrodes while allowing lithium ions in the electrolyte to pass through. Unfortunately, common manufacturing techniques for electrode stack structures result in electrode stack structures being prone to misalignment. The folding and pressing mechanisms are sensitive steps, and any failure to secure the folded portions can lead to electrode slippage and / or separator misalignment. For example, misalignment can occur when the electrodes shift within the stack structure, and it can result in a loss of battery efficiency.

[0030] To mitigate potential misalignment, many manufacturing processes rely on a cathode insulation coating (CIC) that is applied to the cathode near the cathode tab and tab-side edge to provide redundancy in battery cell designs. If the separator folds, shifts, moves, and / or shrinks at any time during cell manufacturing or during in-field use of the cell, or if there is any electrode lamination structure mismatch, the CIC structurally provides an insulating layer that prevents contact and subsequent shorting between the cathode tab or cathode active material (CAM) and the anode active material (AAM) or anode current collector / tab. However, the use of CIC represents a compromise because covering the surface of the cathode with insulating CIC limits electrolyte ingress and ion flow (i.e., CIC inhibits electrode surface processes). Thus, in common practice, the CIC overlaps the cathode by less than 1 mm.

[0031] This disclosure presents a novel cathode insulation coating and coating overlap design that utilizes porous deposition of CIC materials, which provides protective redundancy without sacrificing electrode ionic kinetic performance or electrolyte wetting. Advantageously, the porous CIC can be applied directly to the cathode current collector using a porous material and / or can be formed from a non-porous material using a porous deposition technique in a manner compatible with roll-to-roll electrode manufacturing processes. Providing a porous cathode insulation coating according to one or more embodiments offers several technical advantages over existing electrode stack manufacturing processes. Notably, the porous CIC does not incur all of the transport and capacity losses inherent in so-called full-coverage CIC (where "full-coverage" CIC refers to conventionally applied non-porous CIC), enabling a relatively large CIC to be implemented that overlaps the electrode active materials more strongly, thereby providing extensive protection against edge contact and / or separator failure. In contrast, the active material regions underlying the full-coverage CIC are typically considered "inaccessible" for calculating the available capacity of the cathode. In other words, the porous CIC constructed as described herein provides a higher available capacity for the underlying cathode.

[0032] A vehicle according to an exemplary embodiment is generally designated 100 in Figure 1 which. Vehicle 100 is shown in the form of an automobile having a body 102. Body 102 includes a passenger compartment 104 within which a steering wheel, front row seats, and rear passenger seats (not shown separately) are disposed. A plurality of components are disposed within body 102, including, for example, an electric motor 106 (shown by a projection beneath the front hood). Electric motor 106 is shown for purposes of illustration and discussion only. It should be understood that the configuration, location, size, arrangement, etc. of electric motor 106 are not meant to be particularly limited, and all such configurations (including multi-motor configurations) are within the scope of this disclosure.

[0033] The electric motor 106 is powered by a battery pack 108 (shown by projection near the rear of the vehicle 100). The battery pack 108 is shown for purposes of illustration and discussion only. It should be understood that the configuration, location, size, arrangement, etc. of the battery pack 108 are not meant to be particularly limited, and all such configurations (including split configurations) are within the scope of this disclosure. Additionally, although this disclosure is primarily discussed in the context of a battery pack 108 configured for an electric motor 106 of a vehicle 100, the aspects described herein can be similarly incorporated within any system (vehicle, building, or other) having an energy storage system (e.g., one or more battery packs or modules), and all such configurations and applications are within the scope of this disclosure. As will be detailed herein, the battery pack 108 includes one or more battery cells and / or battery pouches made of an electrode stack fixed using a porous CIC portion.

[0034] Figure 2A An example battery cell 202 according to one or more embodiments is shown. The battery cell 202 can be incorporated as one of a plurality of battery cells in a battery pack (e.g., Figure 1 the battery pack 108 in Figure 2B An example detailed view 204 of the battery cell 202 shown in Figure 2A according to one or more embodiments is shown. As Figure 2B shown, the battery cell 202 includes a cathode current collector 206 having side edges 208. The cathode current collector 206 includes a cathode tab 210 having a cathode tab side edge 212.

[0035] Cathode active material 214 is dispersed on the cathode current collector 206. In some embodiments, the cathode active material 214 is dispersed on those portions of the cathode current collector 206 that do not include the cathode tab 210. In other words, the cathode tab 210 does not contain the cathode active material 214. A cathode insulating coating 216 is dispersed on the cathode active material 214 (some portions of the cathode active material 214 underlying the cathode insulating coating 216 are shown via projection lines) and a portion of the cathode tab 210.

[0036] In some embodiments, the cathode insulating coating 216 is a porous cathode insulating coating. As used herein, a “porous” cathode insulating coating refers to a coating that is macro-porous and / or micro-porous. A macro-porous cathode insulating coating refers to a coating deposited or otherwise formed on the cathode current collector 206 in a pattern having a plurality of openings (lines, holes, etc.) through which direct contact with the underlying cathode active material 214 is possible. A macro-porous cathode insulating coating itself may or may not be made of a porous material. Figure 5A and 5BAn exemplary macroporous cathode insulating coating pattern is shown. It is noted that the macroporous cathode insulating coating does not require a specific geometry. On the other hand, a microporous cathode insulating coating refers to a coating made of a porous material, such as a porous membrane made of a polymer blend (e.g., polytetrafluoroethylene (PTFE), glass fiber, aerogel, and / or cellulose-based insulating material).

[0037] In some embodiments, the cathode insulating coating 216 is a macroporous cathode insulating coating. In some embodiments, the cathode insulating coating 216 is made of a material that is electrochemically stable and highly electrically insulating at the operating voltage of the electrode. Some examples include thermoplastic polymers such as polyvinylidene fluoride (PVDF), polyethylene (PE) (including high-density polyethylene (HDPE) and low-density polyethylene (LDPE)), polypropylene (PP), polyacrylic acid or polyacrylate (PAA) and their mixtures, anode-type binders such as styrene-butadiene rubber (SBR) and carboxymethyl cellulose (CMC), and / or any other type of highly viscous, inert formable coating. In addition, these materials and their mixtures may include ceramics and / or other components that improve the performance, viscosity, formation, deposition, resistivity, color, or any other property of the cathode insulating coating 216.

[0038] As Figure 2B shown, the cathode insulating coating 216 can be applied to extend all the way to the side edge 208 of the cathode current collector 206 on the cathode active material 214. Additionally, the cathode insulating coating 216 can extend all the way to the cathode tab side edge 212 on all or a part of the cathode tab 210 (as shown). In this way, the cathode insulating coating 216 can protect the cathode current collector 206 near the edge of the separator (including within the battery cell 202 but not shown separately), thereby preventing short circuits (e.g., anode to cathode, anode current collector to cathode, etc.), which would otherwise occur if the separator slips or otherwise becomes misaligned with the cathode current collector 206.

[0039] The battery cell 202 can include additional layers, such as multiple stacked anode current collectors alternating with multiple cathode current collectors (including the cathode current collector 206), a separator located between the anode current collector and the cathode current collector, and active materials (including the cathode active material 214) dispersed within the battery cell 202 to cover the anode current collector and the cathode current collector (these additional elements are omitted for simplicity). It should be understood that the battery cell 202 can include any number of layers (e.g., anode layers and cathode layers) and corresponding numbers of separators and any amount of active material as needed, and all such configurations are within the scope of this disclosure.

[0040] The anode current collector and the cathode current collector can be made of a conductive metal sheet or foil. For example, the cathode current collector can be made of aluminum foil, stainless steel, and / or titanium foil to which an active material is attached. Other materials are possible, such as semimetals (e.g., tin, graphite) and alloys of metals and / or their semimetals. In some embodiments, the cathode current collector is made of aluminum foil. The anode current collector can include a coated copper foil, but other materials are also possible and within the scope of this disclosure.

[0041] The separator can include a dielectric material, such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and their composites, but other dielectrics are also within the scope of this disclosure.

[0042] The active material is not particularly limited and can include, for example, various cathode or anode materials (depending on the requirements of the specific application), such as activated carbon powder, nickel manganese cobalt oxide (NMC), lithium iron phosphate (LFP), nickel cobalt aluminum oxide (NCA), nickel cobalt manganese aluminum oxide (NCMA), lithium manganese iron phosphate (LMFP), lithium-rich manganese (LMR), lithium manganese oxide (LMO), graphite, silicon, silicon-graphite composite, tin, tin oxide (SnO2), lithium titanate (Li4Ti5O 12 , LTO), sulfur, and lithium-sulfur (Li-S) composite, lithium metal (Li), and / or lithium alloys, such as lithium-antimony (Li-Sb), lithium-aluminum (Li-Al), and lithium-germanium (Li-Ge).

[0043] Figure 3 An exemplary roll-to-roll coating process 300 according to one or more embodiments is shown. As Figure 3 shown, the roll-to-roll coating process 300 includes a top coating unit 302, a drying unit 304, and a bottom coating unit 306 in the order shown. Although not shown separately, the roll-to-roll coating process 300 can also include additional upstream and downstream manufacturing units, such as a calendering unit upstream of the top coating unit 302.

[0044] In some embodiments, the top coating unit 302 includes a patterned roll 308, a fountain roll 310, a solution coater 312, and a solution container 314 having a coating material 316 therein. The coating material 316 can include, for example, a thermoplastic polymer bath, an anodic binder solution, and / or any other material source for a cathode insulating coating. In some embodiments, the patterned roll 308 is positioned to deposit the coating material 316 on the cathode current collector 206, thereby forming a cathode insulating coating 216 on the top surface 318 of the cathode current collector 206.

[0045] In some embodiments, the pattern roll 308 includes one or more raised surfaces 320 and a nominal surface(s) 322. In some embodiments, the pattern roll 308 and the raised surfaces 320 are positioned against the supply roll 310 such that when the pattern roll 308 rotates, the raised surfaces 320 can be coated with the coating material 316. The nominal surface 322, which is recessed relative to the raised surfaces 320, is not coated with the coating material 316. It has been observed that by varying the arrangement (pattern, size, distribution, etc.) of the raised surfaces 320, the pattern roll 308 can deposit a cathode insulating coating 216 having any desired pattern or structure. Figure 5A Depicts an exemplary pattern produced by the roll-to-roll coating process 300.

[0046] The supply roll 310 is positioned between the pattern roll 308 and the solution applicator 312. In some embodiments, the supply roll 310 is configured to rotate below the solution applicator 312 such that the coating material 316 can be evenly distributed on the supply roll 310 by the solution applicator 312.

[0047] In some embodiments, a back-up roll 324 is positioned opposite the pattern roll 308. The back-up roll 324 can be positioned to provide a fixed surface against which the pattern roll 308 can be pressed, thereby allowing the coating material 316 to be transferred to the top surface 318 of the cathode current collector 206. In some embodiments, the back-up roll 324 is configured to rotate in a direction opposite to that of the pattern roll 308, thereby in combination with the pattern roll 308 allowing the cathode current collector 206 to be pulled along the roll-to-roll coating process 300. The roll-to-roll coating process 300 can also include any number of additional positioning rolls for this purpose, but these positioning rolls are omitted for the sake of convenience.

[0048] In some embodiments, the top coating unit 302 includes a doctor blade 326 positioned against the supply roll 310 and connected to the solution container 314. In some embodiments, the doctor blade 326 is configured to remove excess coating material 316 from the supply roll 310, thereby allowing the excess coating material 316 to be recycled into the solution container 314.

[0049] In some embodiments, the drying unit 304 is after the top coating unit 302. While not meant to be particularly limiting, the drying unit 304 can include, for example, a furnace, an oven, and / or any other heating element for heating and drying the cathode current collector 206 after the deposition of the cathode insulating coating 216.

[0050] In some embodiments, the bottom coating unit 306 is after the drying unit 304. In some embodiments, the bottom coating unit 306 includes a pattern roll 328, a supply roll 330, and a solution container 332 having a coating material 316 therein. In some embodiments, the pattern roll 328 is positioned to deposit the coating material 316 on the cathode current collector 206, thereby forming a cathode insulating coating 334 on the bottom surface 336 of the cathode current collector 206.

[0051] In some embodiments, the pattern roll 328 includes one or more raised surfaces 320 and a nominal surface(s) 322 in a manner similar to that described with respect to the pattern roll 308 of the top coating unit 302, but the pattern of the raised surfaces 320 may be the same or different as needed. In some embodiments, the pattern roll 328 and the raised surfaces 320 are positioned against the supply roll 330 such that when the pattern roll 328 rotates, the raised surfaces 320 can be coated with the coating material 316. The nominal surface 322 recessed relative to the raised surfaces 320 is not coated with the coating material 316.

[0052] The supply roll 330 is located between the pattern roll 328 and the solution container 332. In some embodiments, the supply roll 310 is configured to rotate within the solution container 332 such that the coating material 316 can be evenly distributed on the supply roll 330.

[0053] In some embodiments, a support roll 338 is positioned opposite the pattern roll 328. The support roll 338 can be positioned to provide a fixed surface against which the pattern roll 328 can press, thereby allowing the coating material 316 to be transferred to the bottom surface 336 of the cathode current collector 206. In some embodiments, the support roll 338 is configured to rotate in a direction opposite to that of the pattern roll 328, thereby allowing the cathode current collector 206 to be pulled along the roll-to-roll coating process 300 in combination with the pattern roll 328.

[0054] In some embodiments, the bottom coating unit 306 includes a wiper blade (not shown separately) that is positioned against the supply roll 330 and coupled to the solution container 332. In some embodiments, the wiper blade is configured to remove excess coating material 316 from the supply roll 330, thereby allowing the excess coating material 316 to be recycled into the solution container 332.

[0055] In some embodiments, the roll-to-roll coating process 300 includes both a top coating unit 302 and a bottom coating unit 306. In this type of configuration, the roll-to-roll coating process 300 is a double-sided coating process (as shown). In some embodiments, the roll-to-roll coating process 300 includes only one of the top coating unit 302 and the bottom coating unit 306. In this type of configuration, the roll-to-roll coating process 300 is a single-sided coating process. In either case, the cathode insulating coating 216 and / or the cathode insulating coating 334 can be deposited onto the cathode current collector 206 to any desired thickness. While not meant to be particularly limiting, the cathode insulating coating 216 and / or the cathode insulating coating 334 can be deposited to a thickness of, for example, 5 to 30 nanometers. The cathode insulating coating 216 and the cathode insulating coating 334 can be deposited to the same thickness or different thicknesses as needed.

[0056] Figure 4 An exemplary roll-to-roll coating method 400 according to one or more embodiments is shown. As Figure 4 shown, the roll-to-roll coating process 400 includes a top coating unit 402, a drying unit 404, and a bottom coating unit 406 in the order shown. Although not shown separately, the roll-to-roll coating process 400 can also include additional upstream and downstream manufacturing units, such as a calendering unit upstream of the top coating unit 402.

[0057] In some embodiments, the top coating unit 402 includes a pattern roll 308, a solution applicator 312, and a solution container 314 having a coating material 316 therein. In some embodiments, the pattern roll 308 is positioned to deposit the coating material 316 onto the cathode current collector 206, thereby forming a cathode insulating coating 216 on the top surface 318 of the cathode current collector 206.

[0058] In some embodiments, the pattern roll 308 includes one or more raised surfaces 320 and a nominal surface(s) 322. In some embodiments, the pattern roll 308 and the raised surfaces 320 are positioned against the solution applicator 312 such that when the pattern roll 308 rotates, the nominal surface 322 can be coated with the coating material 316. Notably, in this configuration, the raised surfaces 320 are not coated with the coating material 316, which is contrary to the previously discussed roll-to-roll coating process 300. It has been observed that by varying the arrangement (pattern, size, distribution, etc.) of the raised surfaces 320, the pattern roll 308 can deposit the cathode insulating coating 216 having any desired pattern or structure. Figure 5B An exemplary pattern produced by the roll-to-roll coating process 400 is depicted.

[0059] In some embodiments, the support roller 324 is positioned relative to the pattern roller 308. The support roller 324 can be positioned to provide a fixed surface against which the pattern roller 308 can press, allowing the coating material 316 to be transferred to the top surface 318 of the cathode current collector 206. In some embodiments, the support roller 324 is configured to rotate in a direction opposite to that of the pattern roller 308, thereby allowing the cathode current collector 206 to be pulled along the roll-to-roll coating process 400 in combination with the pattern roller 308. The roll-to-roll coating process 400 may also include any number of additional positioning rollers for this purpose, but these positioning rollers are omitted for convenience.

[0060] In some embodiments, the top coating unit 402 includes a wiper blade 326 positioned against the pattern roller 308 and connected to the solution container 314. In some embodiments, the wiper blade 326 is configured to clear (clean) the raised surface 320 such that the raised surface 320 is free of the coating material 316. In some embodiments, the coating material 316 removed from the pattern roller 308 is recycled into the solution container 314.

[0061] In some embodiments, the drying unit 404 is after the top coating unit 402. While not meant to be particularly limiting, the drying unit 404 can include, for example, a furnace, an oven, and / or any other heating element for heating and drying the cathode current collector 206 after the deposition of the cathode insulating coating 216.

[0062] In some embodiments, the bottom coating unit 406 is after the drying unit 404. In some embodiments, the bottom coating unit 406 includes a pattern roller 328 and a solution container 332 having the coating material 316 therein. In some embodiments, the pattern roller 328 is positioned to deposit the coating material 316 on the cathode current collector 206, thereby forming a cathode insulating coating 334 on the bottom surface 336 of the cathode current collector 206.

[0063] In some embodiments, the pattern roll 328 includes one or more raised surfaces 320 and a nominal surface(s) 322 in a manner similar to that described for the pattern roll 308 of the top coating unit 402, but the pattern of the raised surfaces 320 can be the same or different as needed. In some embodiments, the pattern roll 328 is located within the solution container 332 such that when the pattern roll 328 rotates, the nominal surface 322 can be coated with the coating material 316. In some embodiments, the bottom coating unit 406 includes a squeegee 326 that is positioned against the pattern roll 328 and coupled to the solution container 332. In some embodiments, the squeegee 326 is configured to remove (clean) the raised surfaces 320 such that the raised surfaces 320 are free of the coating material 316 before contacting the bottom surface 336 of the cathode current collector 206. In some embodiments, the coating material 316 removed from the pattern roll 328 is recycled back into the solution container 332.

[0064] In some embodiments, the support roll 338 is positioned opposite the pattern roll 328. The support roll 338 can be positioned to provide a fixed surface against which the pattern roll 328 can press, thereby allowing the coating material 316 to be transferred to the bottom surface 336 of the cathode current collector 206. In some embodiments, the support roll 338 is configured to rotate in a direction opposite to that of the pattern roll 328, thereby allowing the cathode current collector 206 to be pulled along the roll-to-roll coating process 300 in combination with the pattern roll 328.

[0065] In some embodiments, the roll-to-roll coating process 400 includes both the top coating unit 402 and the bottom coating unit 406. In this type of configuration, the roll-to-roll coating process 400 is a double-sided coating process (as shown). In some embodiments, the roll-to-roll coating process 400 includes only one of the top coating unit 402 and the bottom coating unit 406. In this type of configuration, the roll-to-roll coating process 400 is a single-sided coating process. In either case, the cathode insulating coating 216 and / or the cathode insulating coating 334 can be deposited onto the cathode current collector 206 to any desired thickness. While not meant to be particularly limiting, the cathode insulating coating 216 and / or the cathode insulating coating 334 can be deposited to a thickness of, for example, 5 to 30 nanometers. The cathode insulating coating 216 and the cathode insulating coating 334 can be deposited to the same thickness or different thicknesses as needed.

[0066] Note that while the roll-to-roll coating processes 300 and 400 are primarily discussed in the context of pattern rolls, other manufacturing processes for depositing a porous cathode insulating coating, such as additive manufacturing, chemical vapor deposition (with or without a mask), spraying (through a stencil, mask, etc.), gravure printing, etc., can be used in combination with or as an alternative to the pattern rolls described herein, and all such combinations are within the scope of this disclosure.

[0067] Figure 5A and 5B illustrate exemplary patterns of a porous cathode insulating coating in accordance with one or more embodiments. Specifically, Figure 5A is an exemplary pattern 500 after the roll-to-roll coating process 300 described previously for Figure 3 , and Figure 5B is an exemplary pattern 550 after the roll-to-roll coating process 400 described previously for Figure 4 . Pattern 500 may be referred to as a profile grid pattern, and pattern 550 may be referred to as a block pattern. Patterns 500 and 550 are merely illustrative, and other patterns (such as woven geometries, zigzag geometries, cross patterns, honeycomb patterns, perforations, etc.) are possible and within the scope of this disclosure.

[0068] It is observed that since the cathode insulating coating 216 is deposited in a profile grid pattern and a block pattern respectively, portions of the underlying cathode active material 214 remain exposed. That is, depositing the cathode insulating coating 216 as described previously herein (see, for example Figure 3 and Figure 4 ) results in a porous cathode insulating coating having a porous macrostructure. Additionally, Figure 5A and 5B the patterns 500, 550 shown therein are enlarged to better illustrate their respective patterning details. In some embodiments, less than 25%, less than 10%, less than 5%, less than 3%, or less than 1% of the surface of the cathode active material 214 is covered. In some embodiments, pattern 500 and / or pattern 550 are so-called micron-scale patterns. In this type of configuration, pattern 500 and / or pattern 550 include line widths of approximately a few microns (e.g., less than 15 microns, or between 0.5 microns and 5 microns).

[0069] In some embodiments, the cathode insulating coating 216 may include two or more levels of porous macrostructure and microstructure to enable ion flow. For example, the cathode insulating coating 216 may be deposited using a porous material in a cross pattern (or pattern 500 or pattern 550, etc.). That is, the structure within the line width of the deposited pattern itself may be porous. Such a porous cathode insulating coating 216 may be formed using a porous PVDF coating deposited on aluminum by extrusion printing, but other techniques are possible and within the scope of this disclosure.

[0070] By applying the cathode insulating coating 216 on the cathode active material 214 in this manner, the safety factor against separator failure or slippage is significantly enhanced. Further, by applying the cathode insulating coating 216 in a manner that forms a porous macrostructure (e.g., cross pattern, etc.), regardless of whether the cathode insulating coating 216 is made of a porous material or a non-porous material, the electrolyte in the battery cell including the cathode active material 214 is not hindered from transporting ionic current to the underlying cathode active material 214 at the micro level. Additionally, as shown in pattern 500 and pattern 550, only a portion of the cathode active material 214 is covered. Thus, the cathode insulating coating 216 only slightly reduces the total active surface area of the corresponding electrode.

[0071] Although pattern 500 and pattern 550 are exemplary, the cathode insulating coating 216 can be deposited in any arbitrary pattern as long as the resulting structure inherently provides porosity such that the electrolyte can permeate and transport through the cathode insulating coating 216. In other words, by utilizing the cathode insulating coating 216 having a porous macrostructure (having any desired configuration), short-circuit contact of macro sub-components (e.g., anode, cathode, current collector, etc.) is prevented, while at the microscale, the electrolyte is able to reach any large (depending only on the selected pattern) portion of the active surface area of the cathode active material 214. As a result, the loss of ion transport kinetic properties is negligible because the contact with the electrolyte and the ability of the current to reach all active particles are not disrupted.

[0072] Now referring to Figure 6 , a flowchart 600 for coating a cathode current collector with a cathode insulating coating is generally shown according to one embodiment. Referring to Figures 1 - 5B to describe the flowchart 600, and the flowchart 600 may include Figure 6 additional steps not depicted therein. Although depicted in a specific order, the blocks depicted in Figure 6 may be rearranged, subdivided, and / or combined.

[0073] At block 602, the method includes providing a cathode current collector having a cathode tab.

[0074] At block 604, the method includes spreading cathode active material on the cathode current collector.

[0075] At block 606, the method includes forming a cathode insulating coating directly on a portion of the cathode active material and directly on a portion of the cathode tab.

[0076] In some embodiments, the cathode insulating coating includes a porous macrostructure that is patterned such that portions of the cathode active material underlying the cathode insulating coating are exposed, thereby providing a porous cathode insulating coating that prevents misalignment and sliding of the separator while reducing loss of ionic transport kinetic properties.

[0077] In some embodiments, the porous macrostructure includes a micron-scale pattern. In some embodiments, the micron-scale pattern includes one or more lines having a line width of less than 15 microns.

[0078] In some embodiments, the cathode insulating coating includes one or more of a thermoplastic polymer, PVDF, PE, HDPE, LDPE, PP, polyacrylic acid, PAA, anodic binder, SBR, carboxymethyl cellulose, and combinations thereof.

[0079] In some embodiments, the cathode insulating coating includes a porous material such as one or more of PTFE, glass fiber, aerogel, cellulose-based insulating material, and combinations thereof.

[0080] In some embodiments, the cathode insulating coating extends to the edges of the cathode current collector and the cathode tab.

[0081] In some embodiments, the cathode insulating coating extends a distance of at least 5 millimeters above the cathode active material. In some embodiments, the cathode insulating coating extends a distance of at least 10 millimeters above the cathode active material.

[0082] In some embodiments, the cathode insulating coating extends over all of the cathode active material. In some embodiments, the cathode insulating coating extends over at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% of the cathode active material.

[0083] The term "a" does not denote a limitation of quantity, but rather denotes the presence of at least one of the referenced item. Unless the context clearly dictates otherwise, the term "or" means "and / or". References to "aspects" throughout the specification mean that the particular elements (e.g., features, structures, steps, or properties) described in connection with that aspect are included in at least one of the aspects described herein, and may or may not be present in other aspects. Additionally, it should be understood that the described elements may be combined in any suitable manner in the various aspects.

[0084] When an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, no intervening elements are present.

[0085] Unless otherwise stated herein, all test standards are the latest standards in effect as of the filing date of this application, or, if priority is claimed, as of the filing date of the earliest priority application in which the test standards appear.

[0086] Unless otherwise defined, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0087] Although the foregoing disclosure has been described with reference to exemplary embodiments, those skilled in the art will understand that various changes may be made and equivalents may be substituted for its elements without departing from its scope. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from its basic scope. Therefore, it is intended that this disclosure not be limited to the particular embodiments disclosed, but will include all embodiments falling within its scope.

Claims

1. A vehicle, comprising: an electric motor; and a battery pack electrically connected to the electric motor, the battery pack including a plurality of battery cells, each of the plurality of battery cells including: a cathode current collector including a cathode tab; a cathode active material dispersed on the cathode current collector; and a cathode insulating coating directly located on a part of the cathode active material and directly located on a part of the cathode tab; wherein the cathode insulating coating includes a porous macrostructure patterned such that portions of the cathode active material underlying the cathode insulating coating are exposed, thereby providing a porous cathode insulating coating that prevents misalignment and sliding of the separator while reducing loss of ion transport kinetic properties.

2. The vehicle according to claim 1, wherein, The porous macrostructure includes a micron-scale pattern.

3. The vehicle according to claim 2, wherein the micron-scale pattern includes one or more lines having a line width of less than 15 microns.

4. The vehicle according to claim 1, wherein, The cathode insulating coating includes one or more of a thermoplastic polymer, polyvinylidene fluoride (PVDF), polyethylene (PE), high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), polyacrylic acid, polyacrylate (PAA), anodic binder, styrene butadiene rubber (SBR), carboxymethyl cellulose, and combinations thereof.

5. The vehicle according to claim 1, wherein the cathode insulating coating includes a porous material including one or more of polytetrafluoroethylene (PTFE), glass fiber, aerogel, cellulose-based insulating material, and combinations thereof.

6. The vehicle according to claim 1, wherein, The cathode insulating coating extends to the edges of the cathode current collector and the cathode tab.

7. The vehicle according to claim 1, wherein the cathode insulating coating extends at least 5 millimeters above the cathode active material.

8. A battery cell, comprising: a cathode current collector including a cathode tab; a cathode active material dispersed on the cathode current collector; and a cathode insulating coating directly located on a part of the cathode active material and directly located on a part of the cathode tab; wherein the cathode insulating coating includes a porous macrostructure patterned such that some portions of the cathode active material underlying the cathode insulating coating are exposed, thereby providing a porous cathode insulating coating that prevents misalignment and sliding of the separator while reducing loss of ion transport kinetic properties.

9. The battery cell according to claim 8, wherein the porous macrostructure includes a micron-scale pattern.

10. The battery cell according to claim 9, wherein the micron-scale pattern includes one or more lines having a line width of less than 15 microns.

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