Patent Application
20250201861
This disclosure relates to electrode coatings used in batteries.
A variety of materials may be used in the manufacture of battery electrodes. Some materials are used as substrates. Other materials are used as coatings.
A battery with a negative electrode assembly and a positive electrode assembly is provided. The positive electrode assembly comprises a metal foil current collector with a positive active material coated on a part of it. Additionally, a ceramic composite dielectric material, made of a polyimide binder and ceramic filler, is coated on another portion of the metal foil current collector. This coating extends adjacent to and away from the positive active material towards an uncoated end of the metal foil current collector. A separator is disposed between the negative and positive electrode assemblies, such that the ceramic composite dielectric material reaches at least to the end of the separator. The movement of the uncoated end towards the separator, results in contact between the ceramic composite dielectric material and the end of the separator.
The ceramic filler in the battery may be a carbon oxide, such as Al2O3 (Aluminum Oxide), ZrO2 (Zirconium Dioxide), as well as other materials like Al2O3(Aluminum Oxide), ZrO2 (Zirconium Dioxide), AlOOH (Aluminum Oxide Hydroxide), Al(OH)3 (Aluminum Hydroxide), Pb(Zr,Ti)O3 (Lead Zirconate Titanate, PZT), TiO2 (Titanium Dioxide), Y2O3(Yttrium Oxide), YSZ (Yttria-Stabilized Zirconia), Dy2O3 (Dysprosium Oxide), Gd2O3 (Gadolinium Oxide), CeO2 (Cerium Oxide), GDC (Gadolinia-Doped Ceria), MgO (Magnesium Oxide), BaTiO3 (Barium Titanate), NiMn2O4 (Nickel Manganese Oxide), KNaNbO3 (Potassium Sodium Niobate), BiKTiO3 (Bismuth Potassium Titanate), BiFeO3 (Bismuth Ferrite), Bi1.5ZnNb1.5O7 (Bismuth Zinc Niobate), WO (Tungsten Oxide, typically WO3 or WO2), SnO2 (Tin Oxide), LSMO (Lanthanum Strontium Manganese Oxide), LSFC (Lanthanum Strontium Ferrite Cobaltite), AlN (Aluminum Nitride), SiN (Silicon Nitride, typically Si3N4), SiO2 (Silicon Dioxide), ZnO (Zinc Oxide), HfO2 (Hafnium Oxide), TiN (Titanium Nitride), SiC (Silicon Carbide), TiC (Titanium Carbide), WC (Tungsten Carbide), MgB (Magnesium Boride, typically MgB2), TiB (Titanium Boride), CaO (Calcium Oxide), CoFe2O4(Cobalt Ferrite), NiFe2O4(Nickel Ferrite), BaFe2O4 (Barium Ferrite), NiZnFe2O4 (Nickel Zinc Ferrite), ZnFe2O4 (Zinc Ferrite), or MnxCo3-xO4 (Manganese Cobalt Oxide). Alternatively, the ceramic filler may be a nitride, such as Aluminum Nitride (AlN), Silicon Nitride (Si3N4), or Titanium Nitride (TiN). In other configurations, the ceramic filler 28 may be a carbide, such as Silicon Carbide (SiC), Titanium Carbide (TiC), or Tungsten Carbide (WC).
The ratio of polyimide binder to ceramic filler may be between 10:90 and 30:70. The polymeric binder may be PI, PAI, PVDF, PU, and others. The particle size of the ceramic may be less than 10 microns, preferably between 0.1 and 2.0 microns. The thickness of the ceramic composite dielectric material may be between 1 to 100 microns, and more specifically, should be between 1 and 50 microns, measured from the surface of the metal foil current collector to the surface of the ceramic composite dielectric material. In some configurations, the ceramic composite dielectric material extends past the end of the separator.
A manufacturing method for positive electrode assemblies of a battery is described. Each assembly includes a metal foil current collector, a positive active material on part of the current collector, and a ceramic composite dielectric material. This material comprises polyimide binder and ceramic filler, coated on a different portion of the metal foil, extending from the positive active material to an uncoated end. During manufacturing, an automatic chromatic analysis is used to inspect the ceramic composite dielectric material. If this analysis reveals a lack of yellow or brown color in a region of the material, the affected electrode assembly is segregated from the batch. The ceramic filler in the dielectric material may be chosen from a group that includes oxides, nitrides, carbides, or borides. An optional additional step of the method involves assembling the positive electrode assemblies with separators and negative electrodes to form complete battery cells.
Another method for manufacturing positive electrode assembly for a battery, involves applying a ceramic composite dielectric slurry of polyamic acid and ceramic filler, onto a metal foil that serves as the current collector. This slurry is applied from a section of the metal foil that is already coated with an active material, extending to an uncoated end of the foil. After the application, the slurry is cured into a ceramic composite dielectric material. This material comprises a polyimide binder and the ceramic filler. This forms a positive electrode assembly that integrates the ceramic composite dielectric with the metal foil current collector.
A battery with a negative electrode assembly and a positive electrode assembly. The positive electrode assembly comprises a metal foil current collector with a positive active material coated on a part of it. Additionally, a ceramic composite dielectric material, made of a polyimide binder and ceramic filler, is coated on another portion of the metal foil current collector. This coating extends adjacent to and away from the positive active material towards an uncoated end of the metal foil current collector. A separator is placed between the negative and positive electrode assemblies, such that the ceramic composite dielectric material reaches past the end of the separator. The movement of the uncoated end towards the separator, results in contact between the ceramic composite dielectric material and the end of the separator.
Embodiments are described herein. It is to be understood, however, that the disclosed embodiments are merely examples and other embodiments may take various and alternative forms. The figures are not necessarily to scale. Some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art.
Various features illustrated and described with reference to any one of the figures may be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. Various combinations and modifications of the features consistent with the teachings of this disclosure, however, could be desired for particular applications or implementations.
Electrical contact between the cathode tab and the anode layer may occur in some batteries. In some designs, the cathode tab, which connects the cathode to the external circuit, may be positioned close to the anode layer. This proximity raises the likelihood of electrical contact. Such may occur across different styles of batteries, including cylindrical, prismatic, and pouch cells. Each type has distinct structural aspects that may contribute to the potential for contact. For example, the winding process in cylindrical cells may lead to the displacement or deformation of the cathode tab, increasing the likelihood of contact with the anode. Similarly, in prismatic and pouch cells, the method of stacking the layers and the pressure applied to maintain cell integrity may create conditions conducive to contact.
An aspect of this disclosure involves the application of dielectric coatings to prevent the contact mentioned above. In this context, polyamic acid is utilized as a binder and precursor to polyimide in the coating slurry. This substance, upon undergoing thermal curing, transforms into polyimide, forming a stable dielectric coating layer. This process helps in creating a barrier against electrical contact between the cathode tab and the anode layer.
Polyamic acids used in this process may take various forms, including carboxylic acids, neutralized carboxylates, or a blend of these. The presence of neutralized carboxylates, which may include cations like Li+, Na+, K+, NH4+, Cs+, etc., affect the curing process. The cations in neutralized carboxylates may act as catalysts. The cations facilitate the rearrangement and polymerization reactions that convert polyamic acids into polyimides. By lowering the activation energy required for the curing reaction, these cations also reduce the need for high temperatures in the manufacturing process. Polyimides have an intrinsic yellow to brownish coloration. This characteristic is beneficial in the context of manufacturing as it allows for the easier detection of coating defects through conventional vision systems. The polyimide used may be unsubstituted polyimide, bisphenyl-substituted polyimide, polyimide with ethylenic linkage, trifluoromethyl-substituted polyimide, keto-substituted polyimide or other suitable polyimides. Specific examples of polyimides may be PI (polyimide), PAI (poly amide imide), PVDF (polyvinylidene fluoride), PU (polyurethane), polyurea, PC (polycarbonate), PET (polyethylene terephthalate), PMMA (polymethyl methacrylate), PBT (polybutylene terephthalate), PVA (polyvinyl alcohol), or PVB (polyvinyl butyral).
The composition of the dielectric coating detailed may be formulated with the ratio of polyimide binder to ceramic filler adjustable within a range from 1:99 to 99:1. A preferred ratio may be between 10:90 and 30:70. The ceramic filler may be Al2O3 (Aluminum Oxide), ZrO2 (Zirconium Dioxide), as well as other materials like Al2O3 (Aluminum Oxide), ZrO2 (Zirconium Dioxide), AlOOH (Aluminium Oxide Hydroxide), Al(OH)3 (Aluminium Hydroxide), Pb(Zr,Ti)O3 (Lead Zirconate Titanate, PZT), TiO2 (Titanium Dioxide), Y2O3(Yttrium Oxide), YSZ (Yttria-Stabilized Zirconia), Dy2O3 (Dysprosium Oxide), Gd2O3 (Gadolinium Oxide), CeO2 (Cerium Oxide), GDC (Gadolinia-Doped Ceria), MgO (Magnesium Oxide), BaTiO3 (Barium Titanate), NiMn2O4 (Nickel Manganese Oxide), KNaNbO3 (Potassium Sodium Niobate), BiKTiO3 (Bismuth Potassium Titanate), BiFeO3 (Bismuth Ferrite), Bi1.5ZnNb1.5O7 (Bismuth Zinc Niobate), WO (Tungsten Oxide, typically WO3 or WO2), SnO2 (Tin Oxide), LSMO (Lanthanum Strontium Manganese Oxide), LSFC (Lanthanum Strontium Ferrite Cobaltite), AlN (Aluminum Nitride), SiN (Silicon Nitride, typically Si3N4), SiO2 (Silicon Dioxide), ZnO (Zinc Oxide), HfO2 (Hafnium Oxide), TiN (Titanium Nitride), SiC (Silicon Carbide), TiC (Titanium Carbide), WC (Tungsten Carbide), MgB (Magnesium Boride, typically MgB2), TiB (Titanium Boride), CaO (Calcium Oxide), CoFe2O4 (Cobalt Ferrite), NiFe2O4 (Nickel Ferrite), BaFe2O4 (Barium Ferrite), NiZnFe2O4 (Nickel Zinc Ferrite), ZnFe2O4 (Zinc Ferrite), or MnxCo3-xO4 (Manganese Cobalt Oxide). or other various suitable oxides, nitrides, or carbides. The particle size of the ceramic filler material may be up to 10 microns, but preferably less than 2 microns.
The thickness of the coating layer may range from 1 to 100 micrometers on each side, though preferably may be between 1 to 50 micrometers. This coating is applied to the cathode current collector, such as an aluminum foil, and extends slightly over the edge of the cathode coatings. This configuration may reduce deformation of the current collector foil and keep an equal thickness of the top and bottom dielectric coatings.
Referring to the drawings,
A thickness of the ceramic composite dielectric material 22 ranges from 1 to 100 microns, preferably the thickness is between 1 and 50 microns, measured from the surface of the current collector 16 to the surface of the ceramic composite dielectric material 22. The arrangement of the separator 16 between the negative electrode assembly 14 and the positive electrode assembly 12, along with the ceramic composite dielectric material 22, is intended to reduce contact modes which may occur such as separator edge folding or curling. If there is movement of the uncoated portion 24 of the positive electrode 12 toward the separator 16, it results in contact between the ceramic composite dielectric material 22 and the separator 16 or negative electrode 14, rather than direct contact with the uncoated end 24.
In some configurations, the ceramic filler 28 may be a nitride, such as Aluminum Nitride (AlN), Silicon Nitride (Si3N4), or Titanium Nitride (TiN). In other configurations, the ceramic filler 28 may be a carbide, such as Silicon Carbide (SiC), Titanium Carbide (TiC), or Tungsten Carbide (WC). In other configurations, the ceramic filler 28 may be a boride, such as Magnesium Boride (MgB2) or Titanium Boride (TiB2). The polyimide binder 26 to ceramic filler 28 ratio is at least 1:99. However, preferably the ratio of polyimide binder 26 to ceramic filler 28 is between 10:90 and 30:70. The polyimide binder 26 may be selected from a group that includes Polyimide (PI), Polyamide-imide (PAI), Polyvinylidene Fluoride (PVDF), Polyurethane (PU), Polyurea, Polycarbonate (PC), Polyethylene Terephthalate (PET), Polymethyl Methacrylate (PMMA), Polybutylene Terephthalate (PBT), Polyvinyl Alcohol (PVA), or Polyvinyl Butyral (PVB).
The algorithms, methods, or processes disclosed or suggested herein may be deliverable to or implemented by a computer, controller, or processing device, which can include any dedicated electronic control unit or programmable electronic control unit. Similarly, the algorithms, methods, or processes may be stored as data and instructions executable by a computer or controller in many forms including, but not limited to, information permanently stored on non-writable storage media such as read only memory devices and information alterably stored on writeable storage media such as compact discs, random access memory devices, or other magnetic and optical media. The algorithms, methods, or processes may also be implemented in software executable objects. Alternatively, the algorithms, methods, or processes may be embodied in whole or in part using suitable hardware components, such as application specific integrated circuits, field-programmable gate arrays, state machines, or other hardware components or devices, or a combination of firmware, hardware, and software components.
While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of these disclosed materials.
As previously described, the features of various embodiments may be combined to form further embodiments of the disclosure that may not be explicitly described or illustrated. While various embodiments could have been described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art recognize that one or more features or characteristics may be compromised to achieve desired overall system attributes, which depend on the specific application and implementation. These attributes may include, but are not limited to strength, durability, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. As such, embodiments described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics are not outside the scope of the disclosure and may be desirable for particular applications.
