Polyimide coating separator, polyimide coating film, polyamide-imide coating film, and lithium battery

Abstract

To provide a polyimide coating film for a lithium battery such as a high energy or high voltage charging type lithium battery, a separator film or a separator, and a corresponding battery.SOLUTION: A separator contains a porous or fine porous polyimide coating or layer on at least one surface of a fine porous polymer layer, film or film. The polyimide coating or layer may contain other polymer, an additive, a filler or a substance of the same kind. The polyimide coating may be configured to provide oxidation resistance, block dendrite crystal growth, add a dimension and / or mechanical stability, reduce a contraction amount, add high temperature performance (HTMI function), and prevent electric short circuit at a temperature higher than 200°C, and / or polyimide coating of the same kind.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure or invention preferably relates to a polyimide coating film, a separator film, or a separator for a lithium battery such as a high-energy or high-voltage rechargeable lithium battery, and a corresponding battery. The separator preferably includes a porous or microporous polyimide coating or layer on at least one surface of a microporous polymer layer, film, or sheet. The polyimide coating or layer may include other polymers, additives, fillers, or the like. The polyimide coating may be configured, for example, to provide oxidation resistance, prevent dendritic crystal growth, add dimensional and / or mechanical stability, reduce shrinkage, add high-temperature performance (HTMI function), prevent electrical short circuits at temperatures above 200°C, and / or the like. The microporous polymer-based layer may be configured to hold at least a liquid, gel, or polymer electrolyte, conduct ions, and / or block the ion flow between the anode and cathode during thermal runaway (shutdown function). The polyimide-coated separator may be configured, for example, to separate multiple electrodes at high temperatures, provide oxidation resistance, prevent dendritic crystal growth, add dimensional stability, reduce shrinkage, add high-temperature performance (HTMI function), prevent electrical short circuits at temperatures above 200°C, increase fracture strength, and / or block the ion flow between the anode and cathode during thermal runaway (shutdown function). Although the use of a lithium secondary battery is preferred, the polyimide coating film of the present invention may be used as a layer or component of a battery, cell, primary battery, capacitor, fuel cell, fabric, filter, and / or composite, and / or other applications, devices, and / or the like.

[0002] In at least selected embodiments, objects or aspects, the present disclosure or invention relates to polyimide coating films, separator films, or separators for lithium secondary batteries such as high energy or high voltage chargeable lithium ion batteries, polymer batteries, or metal batteries, and corresponding batteries. The separator preferably includes a porous or microporous polyimide coating or layer on at least one surface of a microporous polymer layer, film or film. The polyimide coating or layer may include other polymers, additives, fillers, or the like. The polyimide coating may, for example, provide oxidation resistance, prevent dendritic crystal growth, add dimensional and / or mechanical stability, reduce shrinkage, add high temperature performance (HTMI function), prevent electrical short circuits at temperatures above 200 ° C, and / or may be adapted like the like. The microporous polymer base layer may be adapted to retain at least a liquid, gel, or polymer electrolyte, conduct ions, and / or block the ion flow between the anode and cathode during thermal runaway (shutdown function). The polyimide-coated separator may, for example, separate multiple electrodes at high temperatures, provide oxidation resistance, prevent dendritic crystal growth, add dimensional stability, reduce shrinkage, add high temperature performance (HTMI function), prevent electrical short circuits at temperatures above 200 ° C, increase fracture strength, and / or may be adapted to block the ion flow between the anode and cathode during thermal runaway (shutdown function).

[0003] A separator for a high - energy or high - voltage rechargeable lithium battery and a high - energy or high - voltage rechargeable lithium battery are disclosed herein. According to at least certain embodiments, objects or aspects, the present disclosure or invention relates to a polyimide - coated separator for a high - energy or high - voltage rechargeable lithium battery and a corresponding battery. The separator preferably includes a porous polyimide coating or layer on at least one surface of a microporous polymer layer, film or membrane. The polyimide coating or layer may include other polymers, additives, fillers, or the like. The polyimide coating may, for example, provide oxidation resistance, prevent dendritic crystal growth, add dimensional stability, reduce shrinkage, add high - temperature performance (HTMI function), prevent electrical short - circuits at temperatures above 200 °C, and / or be adapted to perform similar functions. The microporous polymer layer may be adapted to at least retain a liquid electrolyte, conduct ions, and / or block ion flow between the anode and cathode during thermal runaway (shutdown function). and / or be adapted to block ion flow between the anode and cathode during thermal runaway (shutdown function).

[0004] The polyimide of the polyimide coating or layer may be a polyimide, copolyimide, soluble polyimide, solvent - soluble polyimide, water - soluble polyimide, soluble copolyimide, solvent - soluble copolyimide, water - soluble copolyimide, and combinations, mixtures or blends thereof.

Background Art

[0005] A high - energy rechargeable lithium battery may have an anode with an energy capacity of at least 372 milliampere - hours per gram (mAh / g). Such an anode may include, for example, lithium metal, a lithium alloy (such as lithium aluminum), and mixtures of materials such as lithium metal or lithium alloy and carbon, nickel, and copper.

[0006] A high - voltage rechargeable lithium battery may have a voltage of at least 4.5 V, 4.7 V, or higher. Such a battery may have an anode that includes a lithium intercalation compound or a lithium insertion compound.

[0007] The commercial success of certain high energy and high voltage secondary or rechargeable lithium ion batteries is hampered by difficult cycling or safety issues or problems.

[0008] A common solution is a ceramic coated separator (CCS) as described in U.S. Patent No. 6,432,586, which is hereby incorporated by reference in its entirety. Difficulties associated with the use of a particular CCS in a selected battery or cell are that ceramic particles flake off during cell manufacture, the ceramic coating is abrasive, difficult to cut in length, can wear equipment and slitter blades, using the ceramic coating increases thickness, cost, and complexity, and the like occurs.

[0009] Some have proposed the use of gel electrolytes or polymer electrolytes instead of CCS. These gel electrolytes or polymer electrolytes cannot have sufficient dimensional stability (cannot maintain their shape) and cannot have good ionic conductivity. Liquid electrolytes can have conductivity 10X that of gel electrolytes or polymer electrolytes.

[0010] Gel electrolytes or polymer electrolytes also cannot prevent short circuits caused by dendrites. After repeated charge-discharge cycles, lithium dendrite growth can occur. Dendrite growth is a potential problem for all lithium batteries, but the severity of the problem increases when used with high-energy anodes (e.g., metals, metal alloys, or single carbon intercalation anodes). When lithium dendrites grow and penetrate the separator, an internal short circuit of the battery occurs (any direct contact between the anode and the cathode is called an "electrical short circuit", and the contact caused by dendrites is a type of electrical short circuit). Some short circuits caused by extremely small dendrites (i.e., soft short circuits) only reduce the cycle efficiency of the battery. Other short circuits, such as hard short circuits, can also cause thermal runaway of the lithium battery, which is a serious safety problem for lithium rechargeable batteries.

Summary of the Invention

Problems to be Solved by the Invention

[0011] Therefore, there is a need to improve separators for high-energy or high-voltage rechargeable lithium batteries.

Means for Solving the Problems

[0012] According to at least selected embodiments of the present invention or disclosure, the novel or improved separator of the invention can address the above needs, problems, or issues, and / or be suitable for use as a layer or component of batteries, cells, primary batteries, secondary batteries, high-energy or high-voltage rechargeable lithium batteries, capacitors, fuel cells, fabrics, filters, and / or composites, and / or other applications, devices, and / or the like, and can provide a polyimide coating film, separator, or separator film.

[0013] The present disclosure or invention preferably relates to a polyimide coating film, separator film or separator for a lithium battery such as a high energy or high voltage rechargeable lithium battery, and to the corresponding battery. The separator preferably includes a porous or microporous polyimide coating or layer on at least one surface of a microporous polymer layer, film or membrane. The polyimide coating or layer may include other polymers, additives, fillers, or the like. The polyimide coating may, for example, provide oxidation resistance, prevent dendrite crystal growth, add dimensional and / or mechanical stability, reduce shrinkage, add high temperature performance (HTMI function), prevent electrical short circuits at temperatures above 200° C., and / or be adapted like the like. The microporous polymer-based layer may be adapted to hold at least a liquid, gel, or polymer electrolyte, conduct ions, and / or block ion flow between the anode and cathode during thermal runaway (shutdown function). The polyimide-coated separator may, for example, separate multiple electrodes at high temperatures, provide oxidation resistance, prevent dendrite crystal growth, add dimensional stability, reduce shrinkage, add high temperature performance (HTMI function), prevent electrical short circuits at temperatures above 200° C., increase fracture strength, and / or block ion flow between the anode and cathode during thermal runaway (shutdown function). Although the use of a lithium secondary battery is preferred, the polyimide coating film of the present invention may be used as a layer or component of a battery, cell, primary battery, capacitor, fuel cell, fabric, clothing, filter, and / or composite, and / or other applications, devices and / or the like.

[0014] In at least selected embodiments, objects or aspects, the present disclosure or invention relates to a polyimide coating film, a separator film, or a separator for a lithium secondary battery such as a high-energy or high-voltage chargeable lithium-ion battery, a polymer battery, or a metal battery, and to corresponding batteries. The separator preferably includes a porous or microporous polyimide coating or layer on at least one surface of a microporous polymer layer, film or film. The polyimide coating or layer may include other polymers, additives, fillers, or the like. The polyimide coating may be configured, for example, to provide oxidation resistance, prevent dendritic crystal growth, add dimensional and / or mechanical stability, reduce shrinkage, add high-temperature performance (HTMI function), prevent electrical short circuits at temperatures above 200 ° C, and / or the like. The microporous polymer base layer may be adapted to hold at least a liquid, gel, or polymer electrolyte, conduct ions, and / or block the ion flow between the anode and cathode during thermal runaway (shutdown function). The polyimide-coated separator may be adapted, for example, to separate multiple electrodes at high temperatures, provide oxidation resistance, prevent dendritic crystal growth, add dimensional stability, reduce shrinkage, add high-temperature performance (HTMI function), prevent electrical short circuits at temperatures above 200 ° C, increase fracture strength, and / or the like. Block the ion flow between the anode and cathode during thermal runaway (shutdown function).

[0015] The polyimide of the polyimide coating or layer may be a polyimide, a copolyimide, a polyimide mixture or blend, a soluble polyimide, a solvent-soluble polyimide, a water-soluble polyimide, a soluble copolyimide, a solvent-soluble copolyimide, a water-soluble copolyimide, a polyamide-imide, and combinations, mixtures or blends thereof.

[0016] Separators for high-energy or high-voltage chargeable lithium batteries and high-energy or high-voltage chargeable lithium batteries are disclosed herein. At least certain embodiments, objects or aspects According to one aspect, the present disclosure or invention relates to a polyimide-coated separator for a high-energy or high-voltage rechargeable lithium battery and a corresponding battery. The separator preferably includes a porous polyimide coating or layer on at least one surface of a microporous polymer layer, film, or sheet. The polyimide coating or layer may include other polymers, additives, fillers, or the like. The polyimide coating may, for example, provide oxidation resistance, prevent dendritic crystal growth, add dimensional stability, reduce shrinkage, add high-temperature performance (HTMI function), prevent electrical short circuits at temperatures above 200° C., and / or be adapted to do the like. The microporous polymer layer may be adapted to at least retain a liquid electrolyte, conduct ions, and / or block the ion flow between the anode and cathode during thermal runaway (shutdown function).

[0017] According to at least certain embodiments, the present disclosure or invention relates to a novel or improved separator for a high-energy or high-voltage rechargeable lithium battery and a corresponding battery. The separator of the present invention includes at least one polyimide layer, treatment, material, film formation, or coating and at least one microporous polymer-based layer. The polyimide-coated separator is adapted to at least prevent dendritic crystal growth and prevent electrical short circuits. The polymer-based layer is adapted to at least block the ion flow between the anode and cathode during thermal runaway.

[0018] General chemical formula of polyimide:

[0019] [Chemical formula]

[0020] Polyimide (sometimes abbreviated as PI) is a polymer composed of imide monomers. Polyimide has high heat resistance. A typical polyimide is Kapton® which is produced by condensing pyromellitic dianhydride and 4,4'-oxydianiline.

[0021] 2D Structure of Polyimide: Two-dimensional display of this compound

[0022] [Chemical formula]

[0023] Polyamide-imide is an amorphous polymer that is either thermosetting or thermoplastic and has excellent mechanical, thermal, and chemical resistance properties. Polyamide-imide is prepared from isocyanate and TMA (trimellitic anhydride) in N-methyl-2-pyrrolidone (NMP). A well-known wholesaler of polyamide-imide is Solvay Specialty Polymers, and the trademark Torlon® is used.

[0024] Polyamide-imide exhibits a combination of properties of both polyamide and polyimide, such as high strength, melt processability, extremely high heat capacity, and a wide range of chemical resistance.

[0025] A soluble polyimide with a high glass transition temperature (Tg) can be prepared, for example, from four commercially available aromatic dianhydrides (i.e., BPDA, OPDA, 6FDA, and BPADA) and a rigid aromatic diamine containing a t-butyl group (3,3'-di-t-butylbenzidine).

[0026] Examples of soluble polyimides include MATRIMID XU5218 commercially available from Ciba-Geigy, ULTEM 1000P commercially available from General Electric, or LaRC-CP1, LaRC-CP2, and LaRC-Si available from Imitec, Inc. (Schenectady, N.Y).

[0027] Matrimid® 5218 is a soluble thermoplastic polyimide. It is fully imidized during production and does not need to be treated at high temperatures. Matrimid 5218 can be dissolved in various common solvents. When these solvents are evaporated, a strong, durable, and tough coating remains.

[0028] Nexolve CP1 fluorinated polyimide can provide excellent physical and electrical properties over a wide temperature range and in many harsh environments. This fluorinated poly imide can be easily dissolved in many solvents for various applications including MIBK, DMF, THF, and others.

[0029] Polyimide 1 - BPDA with a rigid structure and high Tg can also be dissolved in NMP, DMAc, and m - cresol at 60 °C. When the concentration of this polyimide solution is diluted by a factor of 2, it can also be dissolved in DMAc and m - cresol at room temperature.

[0030] Certain soluble polyimides may be soluble in organic solvents, and the organic solvents can also dissolve the polyimide precursors. Therefore, soluble polyimides can be prepared by a one - step method.

[0031] Selected soluble polyimides with side chains introduced into the PI backbone can be a beneficial approach to improving solubility because the side chains effectively prevent the coplanarity of the aromatic rings and reduce the packing efficiency of the main chain.

[0032] Selected highly soluble polyimides can be synthesized from various aromatic tetracarboxylic dianhydrides and aromatic diamines [4,4'-methylenebis(2 - t - butylaniline)] containing t - butyl pendant groups. Such polyimides may exhibit excellent solubility in common solvents such as chloroform, tetrahydrofuran, and dioxane at room temperature.

[0033] A specific soluble polyimide having a polyalicyclic structure can be prepared by reacting 2,3,5-tricarboxycyclopentylacetic dianhydride (TCA-AH) with an aromatic diamine (two-step polymerization system).

[0034] According to one or more preferred possible processes, one or more strong solvents, acids, or the like are used to convert an insoluble polyimide into a soluble polyimide. The soluble polyimide is then mixed with a solvent and particles to form a coating slurry, which is coated onto a base film, dried, and the particles are then removed from the dried coating to form a base film or separator coated with a preferred porous polyimide.

[0035] According to one or more preferred possible processes, one or more strong solvents, acids, or the like are used to convert an insoluble polyimide into a soluble polyimide. The soluble polyimide is then mixed with a solvent and particles to form a coating slurry, which is coated onto a base film and dried, but the particles may or may not be removed from the dried coating to form a base film or separator coated with a polyimide. For example, the particles may be dissolved in an electrolyte, absorbed or adsorbed by the electrolyte, wetted with the electrolyte, and / or the like.

[0036] A separator for a high - energy or high - voltage rechargeable lithium battery and a high - energy or high - voltage rechargeable lithium battery are disclosed herein. According to at least certain embodiments, objects or aspects, the present disclosure or invention relates to a polyimide - coated separator for a high - energy or high - voltage rechargeable lithium battery and a corresponding battery. The separator preferably includes a porous polyimide coating or layer on at least one surface of a microporous polymer layer, film or sheet. The polyimide coating or layer may include other polymers, additives, fillers, or the like. The polyimide coating may, for example, provide oxidation resistance, prevent dendritic crystal growth, add dimensional stability, reduce shrinkage, add high - temperature performance (HTMI function), prevent electrical short - circuits at temperatures above 200 °C, and / or be adapted like the like. The microporous polymer layer may be adapted to at least hold a liquid electrolyte, conduct ions, and / or block the ion flow between the anode and cathode during thermal runaway (shutdown function).

[0037] The polyimide of the polyimide coating or layer may be a polyimide, copolyimide, soluble polyimide, solvent - soluble polyimide, water - soluble polyimide, soluble copolyimide, solvent - soluble copolyimide, water - soluble copolyimide, and combinations, mixtures or blends thereof. For purposes of illustrating the invention, in the drawings, preferred embodiments of the invention are shown. However, it should be understood that the invention is not limited to the specific structures and specific devices shown.

Brief Description of the Drawings

[0038]

Figure 1

Figure 2

[0039] A typical lithium battery (or cell) includes a lithium metal or alloy anode, a cathode, and a separator disposed between the anode and the cathode, all of which are packaged inside a can or pouch of a cylindrical cell or “jelly roll” cell, or a prismatic cell or a laminated cell. The present invention is not limited to a particular battery or cell configuration and may also be suitable for button cells, polymer cells, and the like. Further, the electrolyte may be a liquid (organic or inorganic) or a gel (or polymer). For convenience, the present invention is described with respect to a cylindrical cell having a liquid organic electrolyte, but is not limited thereto and can also be used in other cell types (e.g., energy storage systems, capacitors, composite cells and capacitors) and configurations.

[0040] A preferred possible anode should have high energy or high voltage performance or capacity, preferably 372 mAh / g or more, preferably 700 mAh / g or more, and most preferably 1000 mAh / g or more. Preferred anodes may be composed of a lithium metal foil or a lithium alloy foil (e.g., a lithium aluminum alloy), or a mixture of a lithium metal and / or a lithium alloy and a material such as carbon (e.g., coke, graphite), nickel, copper. The anode may include an intercalation compound containing lithium or an insertion compound containing lithium.

[0041] The cathode may be any cathode compatible with the anode and may include an intercalation compound, an insertion compound, or an electrochemically active polymer. Suitable intercalation materials are, for example, MoS2, FeS2, MnO2, TiS2, NbSe3, LiCo O2, LiNiO2, LiMn2O4, V6O 13 It includes V2O5 and CuCl2. Suitable cathode polymers include, for example, polyacetylene, polypyrrole, polyaniline, and polythiopene.

[0042] This electrolyte may be a liquid or a gel (or a polymer). Typically, this electrolyte mainly consists of a salt and a medium (for example, in a liquid electrolyte, the medium is called a solvent, and in a gel electrolyte, the medium may be a polymer matrix). This salt may be a lithium salt. This lithium salt may be, for example, LiPF6, LiAsF6, LiCF3SO3, LiN(CF3SO3)3, LiBF6, and LiClO4, BETTE electrolyte (3M C orp. (Minneapolis MN) commercially available) and combinations thereof may also be included. Solvents may include, for example, ethylene carbonate (EC), propylene car bonate (PC), EC / PC, 2-MeTHF (2-methyltetrahydrofuran) / EC / PC, EC / DMC (dimethyl carbonate), EC / DME (dimethyl ethane), EC / DEC (diethyl carbonate), EC / EMC (ethyl methyl carbonate), EC / EMC / DMC / DEC, EC / EMC / DMC / DEC / PE, PC / DME, and DME / PC. The electrolyte polymer matrix may include, for example, PVDF (polyvinylidene fluoride), PVDF:THF (PVDF:tetrahydrofuran), PVDF:CTFE (PVDF:chlorotrifluoroethylene), PVDF-HFP, PAN (polyacrylonitrile), and PEO (polyethylene oxide).

[0043] Referring to FIGS. 1 and 2, an exemplary separator includes at least one polyimide coating or layer on at least one surface of at least one microporous polymer layer, base film, or membrane. In a battery, this polyimide coating or layer must be sufficiently ion-conductive to provide an ion flow between the anode and the cathode such that the cell generates current in a desired amount. This coating and the base film should adhere well to each other. This coating and the base film layer may be formed by lamination, coextrusion, film formation, or coating methods. This polyimide coating may be a coated or separated layer, both having a thickness in the range of 0.001 μm to 50 μm, preferably 0.01 μm to 15 μm or less. The microporous polymer layer is preferably a separated membrane having a thickness in the range of 5 μm to 50 μm, preferably 4 μm to 12 μm or more. The overall thickness of the separator is in the range of 5 μm to 100 μm, preferably in the range of 6 μm to 25 μm.

[0044] This polyimide coating may be porous, microporous, or non-porous (preferably porous, but it should be understood that when a non-porous coating layer is wetted with or immersed in an electrolyte, it can become ion-conductive depending on the material constituting the coating layer).

[0045] The microporous polymer-based film may be any commercially available separator microporous membrane (e.g., single-layer or multi-layer), such as Celgard® dry process products manufactured by Celgard, LLC (Charlotte, North Carolina), or Hipore® wet process products manufactured by Asahi Kasei Corporation (Tokyo, Japan). The base film has a porosity in the range of 20 - 80%, preferably in the range of 30 - 60%, an average pore size in the range of 0.02 - 2 μm, preferably in the range of 0.05 - 0.5 μm, and may have a Gurley number in the range of 5 - 150 seconds, preferably in the range of 15 - 60 seconds. (The Gurley number refers to the time required for 10 cm 3 of air to pass through a 6.4 cm 2 (1 square inch) membrane at a 31 cm (12.2 inch) water column), and is preferably polyolefin-based. Preferred polyolefins include polyethylene and / or polypropylene. Polypropylene may be most preferred (high-temperature polymer, oxidation resistance).

[0046] The aforementioned separator is mainly designed for use in high-energy or high-voltage charged lithium batteries, but may also be used in other battery systems where dendritic crystal growth is a problem.

[0047] In some examples, the base film or coating substrate can include a semi-crystalline polymer, such as a polymer having a crystallinity in the range of 20 - 80%.

[0048] In some embodiments, the substrates described herein can include a single layer, two layers, three layers, or multiple layers. For example, a three-layer or multi-layer substrate can include two outer layers and one or more inner layers. In some embodiments, the substrate can include 1, 2, 3, 4, 5 or more inner layers. As described in more detail below, each of these layers can be co-extruded and / or laminated together.

[0049] The substrates described in this specification can be made by a dry stretching process (the Celgard® dry stretching process described in this specification), in which one or more polymers are extruded to form the substrate. Each of the outer layer and the inner layer can be extruded singly, in which case the layer is extruded by itself without any sub-layers, or each layer can include a plurality of co-extruded sub-layers. For example, each layer can include a plurality of sub-layers such as two co-extruded sub-layers, three co-extruded sub-layers, or a multi-layer sub-layer substrate, and each can be collectively regarded as a "layer". The number of sub-layers in two co-extruded layers is two, the number of layers in three co-extruded layers is three, and the number of sub-layers in a co-extruded multi-layer substrate is two or more, three or more, four or more, five or more, etc. The exact number of sub-layers in the co-extruded layer is defined by the die design and not necessarily by the materials co-extruded to form the co-extruded layer. For example, a co-extruded two-layer, three-layer, or multi-layer sub-layer substrate can be formed using the same material in each of these two, three, or four or more sub-layers, but these sub-layers will still be regarded as separate sub-layers even though each sub-layer is made of the same material.

[0050] In some embodiments, the three-layer or multi-layer substrates described in this specification can include two outer layers (such as a first outer layer and a second outer layer, etc.) and one or more inner layers. The plurality of inner layers can be singly extruded layers or co-extruded layers. A lamination barrier can be formed between each of the inner layers and / or between each of the outer layers and one of the inner layers. A lamination barrier can be formed when two surfaces, such as two surfaces of different substrates or layers, are laminated together using heat, pressure, or heat and pressure.

[0051] In some embodiments, the substrates described herein are the following: PP, PE, PP / PP, PP / PE, PE / PP, PE / PE, PP / PP / PP, PP / PP / PE, PP / PE / PE, PP / PE / PP, PE / PP / PE, PE / PE / PP, PP / PP / PP / PP, PP / PE / PE / PP, PE / PP / PP / PE, PP / PE / PP / PP, PE / PE / PP / PP, PE / PP / PE / PP, PP / PE / PE / PE / PP, PE / PP / PP / PP / PE, PP / PP / PE / PP / PP, PE / PE / PP / PP / PE / PE, PP / PE / PP / PE / PP, PP / PP / PE / PE / PP / PP, PE / PE / PP / PP / PE / PE, PE / PP / PE / PP / PE / PP, PP / PE / PP / PE / PP / PE, PP / PP / PP / PE / PP / PP / PP, PE / PE / PE / PP / PE / PE / PE, PP / PE / PP / PE / PP / PE / PP, PE / PP / PE / PP / PE / PP / PE, PE / PP / PE / PP / PE / PP / PE / PP, PP / PE / PP / PE / PP / PE / PP / PE, PP / PP / PE / PE / PP / PP / PE / PE, PP / PE / PE / PE / PE / PE / PE / PP, PE / PP / PP / PP / PP / PP / PP / PE, PP / PP / PE / PE / PEPE / PP / PP, PP / PP / PP / PP / PE / PE / PE / PE, PP / PP / PP / PP / PE / PP / PP / PP / PP, PE / PE / PE / PE / PP / PE / PE / PE / PE, PP / PE / PP / PE / PP / PE / PP / PE / PP, PE / PP / PE / PP / PE / PP / PE / PP / PE, PE / PE / PE / PE / PE / PP / PP / PP / PP, PP / PP / PP / PP / PP / PE / PE / PE / PE, PP / PP / PP / PP / PP / PE / PE / PE / PE / PE, PE / PE / PE / PE / PE / PP / PP / PP / PP / PP, PP / PE / PP / PE / PP / PE / PP / PE / PP / PE, PE / PP / PE / PP / PE / PP / PE / PP / PE / PP, PE / PP / PP / PP / PP / PP / PP / PP / PP / PP / PE, PP / PE / PE / PE / PE / PE / PE / PE / PE / PE / PP, PP / PP / PE / PE / PP / PP / PE / PE / PP / PP,It can have a non-limiting configuration that is PE / PE / PP / PP / PP / PP / PP / PP / PP / PE / PE, PP / PP / PP / PE / PE / PP / PP / PP / PP / PE, or PE / PE / PE / PP / PP / PE / PE / PE / PP / PP. For the purposes of reference in this specification, PE means a single layer within a multilayer substrate that includes PE. Similarly, PP means a single layer within a multilayer substrate that includes PP. Thus, given the designation PP / PE, it represents a two-layer substrate having a polypropylene (PP) layer and a polyethylene (PE) layer.,

[0052] Individual layers in the substrate may have multiple sub-layers and can be formed by co-extruding or bonding the individual sub-layers to form the individual layers of the multilayer substrate. When using a multilayer substrate having the structure PP / PE / PP, each individual PP or PE layer can include two or more co-extruded sub-layers. For example, when each individual PP or PE layer includes three sub-layers, each individual PP layer can be represented as PP = (PP1, PP2, PP3), and each individual PE layer can be represented as PE = (PE1, PE2, PE3). Thus, the structure PP / PE / PP can be represented as (PP1, PP2, PP3) / (PE1, PE2, PE3) / (PP1, PP2, PP3). The composition of each of the sub-layers PP1, PP2, and PP3 may be the same, or each sub-layer may have a polypropylene composition that is different from one or both of the other polypropylene sub-layers. Similarly, the composition of each of the sub-layers PE1, PE2, and PE3 may be the same, or each sub-layer may have a polyethylene composition that is different from one or both of the other polyethylene sub-layers. This rule also applies to other multilayer substrates having layers that are approximately the exemplary three-layer substrate described above.,

[0053] In some embodiments, the substrate described herein has an overall thickness of from 1 μm to 60 μm, from 1 μm to 55 μm, from 1 μm to 50 μm, from 1 μm to 45 μm, from 1 μm to 40 μm, from 1 μm to 35 μm, from 1 μm to 30 μm, from 1 μm to 25 μm, from 1 μm to 20 μm, from 1 μm to 15 μm, from 1 μm to 10 μm, from 5 μm to 50 μm, from 5 μm to 40 μm, from 5 μm to 30 μm, from 5 μm to 25 μm, from 5 μm to 20 μm, from 5 μm to 10 μm, from 10 μm to 40 μm, from 10 μm to 35 μm, from 10 μm to 30 μm, or from 10 μm to 20 μm.

[0054] In some embodiments, the thickness of each layer in a two-layer substrate, a three-layer substrate, or a multi-layer substrate may be equal to the thickness of other layers, or may be thinner or thicker than the thickness of other layers. For example, when the substrate is a three-layer substrate including a structure of PP / PE / PP (polypropylene / polyethylene / polypropylene) or PE / PP / PE (polyethylene / polypropylene / polyethylene), the thickness of this polypropylene layer may be equal to the thickness of the polyethylene layer, may be thinner than the thickness of the polyethylene layer, or may be thicker than the thickness of the polyethylene layer.

[0055] In some embodiments, the substrate described herein may be a PP / PE / PP (polypropylene / polyethylene / polypropylene) or PE / PP / PE (polyethylene / polypropylene / polyethylene) substrate in which three layers are laminated. In some examples, the structural ratios of these layers of the substrate may include 45 / 10 / 45%, 40 / 20 / 40%, 39 / 22 / 39%, 38 / 24 / 38%, 37 / 26 / 37%, 36 / 28 / 36%, 35 / 30 / 35%, 34.5 / 31 / 34.5%, 34 / 32 / 34%, 33.5 / 33 / 33.5%, 33 / 34 / 33%, 32.5 / 35 / 32.5%, 32 / 36 / 32%, 31.5 / 37 / 31.5%, 31 / 38 / 31%, 30.5 / 39 / 30.5%, 30 / 40 / 30%, 29.5 / 41 / 29.5%, 29 / 42 / 29%, 28.5 / 43 / 28.5%, 28 / 44 / 28%, 27.5 / 45 / 27.5%, or 27 / 46 / 27%.

[0056] The substrates described in this specification may further include fillers, elastomers, wetting agents, lubricants, flame retardants, nucleating agents, antioxidants, colorants, and / or other additional components that do not conflict with the objectives of the present disclosure. For example, the substrate can include fillers such as calcium carbonate, zinc oxide, diatomaceous earth, talc, kaolin, synthetic silica, mica, clay, boron nitride, silicon dioxide, titanium dioxide, barium sulfate, aluminum hydroxide, magnesium hydroxide, and the like, or combinations thereof. Examples of elastomers include ethylene-propylene (EPR), ethylene-propylene-diene (EPDM), styrene-butadiene (SBR), styrene-isoprene (SIR), ethylidene norbornene (ENB), epoxy, and polyurethane, or combinations thereof. Examples of wetting agents include ethoxylated alcohols, primary polymeric carboxylic acids, glycols (such as polypropylene glycol and polyethylene glycol), functionalized polyolefins, and the like.

[0057] Examples of lubricants include silicone, fluoropolymers, oleamide, stearamide, erucamide, calcium stearate, lithium stearate, or other metal stearates. Examples of flame retardants include brominated flame retardants, ammonium phosphate, ammonium hydroxide, alumina trihydrate, and phosphate esters. Examples of nucleating agents can include any nucleating agent that does not conflict with the objectives of the present disclosure, such as the β-nucleating agent for polypropylene disclosed in U.S. Patent No. 6,602,593.

[0058] In some of the embodiments described herein, the substrate can be made by a dry stretching process in some examples. The substrate should be understood to be a thin, flexible polymer membrane, film, sheet, foil, or substrate in which a plurality of pores extend. In some cases, the porous substrate is made by a dry stretching process (also known as the CELGARD® dry stretching process), which refers to the formation of pores by stretching a non-porous, semi-crystalline, extruded polymer precursor in the machine direction (MD), the transverse direction (TD), or both MD and TD. See, for example, Kesting, Robert E., Synthetic Polymeric Membranes, A Structural Perspective, Second Edition, John Wiley & Sons, New York, N.Y., (1985), pages 290-297, the contents of which are incorporated herein by reference. Such a dry stretching process is different from wet processes and particle stretching processes. In the wet process, also known as the phase inversion process, extraction process, or TIPS process, generally, a polymer raw material is mixed with a processing oil (sometimes also called a plasticizer), the mixture is extruded, and pores are formed when the processing oil is removed. These wet process substrates can be stretched before and after the removal of the oil, but the principle of the pore formation mechanism is the use of the processing oil. See, for example, Kesting, Ibid., pages 237-286, the contents of which are incorporated herein by reference. In the particle stretching process, particles such as silica or calcium carbonate are used as pore formers. A polymer raw material is mixed with the particles, the mixture is extruded, and pores are formed when the particles are removed. These particle-filled substrates can be stretched before and after the removal of the particles, but the principle of the pore formation mechanism is the use of the particles. The porous substrates described herein can, in some examples, preferably be all Celgard® polyolefin porous separator substrates available from Celgard, LLC (Charlotte, N.C).

[0059] The porous substrate may be a macroporous substrate, a mesoporous substrate, a microporous substrate, or a nanoporous substrate. The porosity of the substrate may be any porosity that does not conflict with the objectives of the present disclosure. For example, any porosity that can form an acceptable battery separator is acceptable. In some embodiments, the porosity of the porous substrate is 20 - 90%, 20 - 80%, 40 - 80%, 20 - 70%, 40 - 70%, 40 - 60%, greater than 20%, greater than 30%, or greater than 40%. The porosity is measured using ASTM D - 2873 and is defined as the ratio of the hollow space such as pores in a certain area of the porous substrate measured in the machine direction (MD) and the transverse direction (TD) of the substrate. In some embodiments, the pores are slit - shaped, circular with a sphericity of 0.25 - 8.0, elliptical, trapezoidal, or oval.

[0060] The substrate can have any Gurley that does not conflict with the objectives of the present disclosure, such as a Gurley acceptable for use as a battery separator. The Gurley is the Japanese Industrial Standard (JIS Gurley) and can be measured using a permeability tester such as an OHKEN permeability tester. The JIS Gurley is defined as the time (seconds) required for 100 cm 3 of air to pass through a 6.4 cm 2 (1 square inch) substrate at a constant pressure of 12.4 cm (4.9 inches) of water column. In some embodiments, the porous film or substrate described herein has a JIS Gurley (seconds / 100 cc) of 100 or more, 150 or more, 160 or more, 170 or more, 180 or more, 190 or more, 200 or more, 210 or more, 220 or more, 230 or more, 240 or more, 250 or more, 260 or more, 270 or more, 280 or more, 290 or more, 300 or more, 310 or more, 320 or more, 330 or more, 340 or more, 350 or more, 100 - 800, 200 - 700, 200 - 600, 200 - 500, 200 - 400, 200 - 300, or 300 - 600.

[0061] The substrate can have a height of 200 gf or more, 210 gf or more, 220 gf or more, 230 gf or more, 240 gf or more, 250 gf or more, 260 gf or more, 270 gf or more, 280 gf or more, 290 gf or more, 300 gf or more, 310 gf or more, 320 gf or more, 330 gf or more, 340 gf or more, 350 gf or more, or 400 gf or more in an uncoated state.

[0062] In some embodiments, the substrates described herein can include one or more additives in at least one layer of the porous substrate. In some embodiments, at least one layer of the porous substrate includes more than one additive, such as two, three, four, five, or more. The additive may be present in one or both of the outermost layers of the porous substrate, in one or more inner layers, in all of the inner layers, or in both all of the inner layers and the outermost layers. In some embodiments, the additive may be present in one or more outermost layers and one or more innermost layers. In such embodiments, the additive may be released from the outermost layer over time, and the additive supply in the outermost layer can be replenished by moving the additive in the inner layer to the outermost layer. In some embodiments, each layer of the substrate may include a different additive or combination of additives than an adjacent layer of the substrate.

[0063] In some embodiments, the additive includes a functionalized polymer. As would be understood by one of ordinary skill in the art, a functionalized polymer is a polymer having a functional group arising from the polymer backbone. In some embodiments, the functionalized polymer is a maleic anhydride-functionalized polymer. In some embodiments, the maleic anhydride-modified polymer is maleic anhydride homopolymer polypropylene, copolymer polypropylene, high-density polypropylene, low-density polypropylene, ultra-high-density polypropylene, ultra-low-density polypropylene, homopolymer polyethylene, copolymer polyethylene, high-density polyethylene, low-density polyethylene, ultra-high-density polyethylene, ultra-low-density polyethylene.

[0064] In some embodiments, the additive includes an ionomer. An ionomer is a copolymer containing both ionic-containing groups and non-ionic repeating groups, as understood by one of ordinary skill in the art. The ionic-containing repeating groups may sometimes constitute less than 25%, less than 20%, or less than 15% of the ionomer. In some embodiments, the ionomer may be a Li-based, Na-based, or Zn-based ionomer.

[0065] In some embodiments, the additive includes cellulose nanofibers.

[0066] In some embodiments, the additive includes inorganic particles with a narrow particle size distribution. For example, the difference between D10 and D90 of the distribution is less than 100 nm, less than 90 nm, less than 80 nm, less than 70 nm, less than 60 nm, less than 50 nm, less than 40 nm, less than 30 nm, less than 20 nm, or less than 10 nm. In some embodiments, the inorganic particles are selected from at least one of SiO2, TiO2, or a combination thereof.

[0067] In some embodiments, the additive includes a lubricant. The lubricant or slip agent described herein may be any lubricant that does not conflict with the objectives of the present disclosure. As understood by one of ordinary skill in the art, a lubricant is a compound that functions to reduce the frictional force between various different surfaces, including the following: polymer: polymer, polymer: metal, polymer: organic material, and polymer: inorganic material. Specific examples of the lubricant or slip agent described herein are compounds containing siloxy functional groups, including siloxanes and polysiloxanes, and fatty acid salts including metal stearates.

[0068] As the lubricant described in this specification, compounds containing 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, or 10 or more siloxy groups may be used. As understood by those skilled in the art, siloxane is a type of molecule containing an alternating silicon atom (Si) and oxygen atom (O) skeleton, and each silicon atom may have a saturated or unsaturated organic group such as bonded hydrogen (H), -CH3, or C2H5. Polysiloxane is a polymerized siloxane and usually has a high molecular weight. In some embodiments described in this specification, the polysiloxane may have a high molecular weight, such as ultra-high molecular weight polysiloxane. In some embodiments, the high molecular weight or ultra-high molecular weight polysiloxane may have a weight average molecular weight ranging from 500,000 to 1,000,000.

[0069] The fatty acid salts described in this specification may be any fatty acid salts that do not conflict with the objectives of the present disclosure. In some examples, the fatty acid salts may be any fatty acid salts that function as lubricants. The fatty acid of this fatty acid salt may be a fatty acid having 12 to 22 carbon atoms. For example, the metal fatty acid may be selected from the group consisting of lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, palmitoleic acid, behenic acid, erucic acid, and arachidic acid. The metal may be any metal that does not conflict with the objectives of the present disclosure. In some examples, the metal is an alkali metal or alkaline earth metal such as Li, Be, Na, Mg, K, Ca, Rb, Sr, Cs, Ba, Fr, and Ra. In some embodiments, the metal is Li, Be, Na, Mg, K, or Ca.

[0070] The fatty acid salt may be lithium stearate, sodium stearate, lithium oleate, sodium oleate, sodium palmitate, lithium palmitate, potassium stearate, or potassium oleate.

[0071] The lubricant containing a fatty acid salt described in this specification may have a melting point of 200 °C or higher, 210 °C or higher, 220 °C or higher, 230 °C or higher, or 240 °C or higher. Fatty acid salts such as lithium stearate (melting point 220 °C) or sodium stearate (melting point 245 - 255 °C) have such melting points.

[0072] In some embodiments, the additive can include one or more nucleating agents. As will be understood by one of ordinary skill in the art, a nucleating agent is, in some embodiments, a material, an inorganic substance, that aids in increasing or enhancing polymer crystallization, including a semi-crystalline polymer. .

[0073] In some cases, the additive may include a cavitation promoter. A cavitation promoter is, as will be understood by those skilled in the art, a material that forms, aids in forming, increases the formation of, or enhances the formation of air bubbles or hollow spaces in a polymer.

[0074] The additive may, in some examples, include a fluoropolymer, such as a fluoropolymer detailed herein.

[0075] In some embodiments, the additive may include a cross-linking agent.

[0076] The additive described in this specification may, in some embodiments, include an X-ray detectable material. The X-ray detectable material can be any X-ray detectable material that does not conflict with the purposes of this disclosure, such as those disclosed in U.S. Patent No. 7,662,510, which is hereby incorporated by reference in its entirety. A suitable amount of the X-ray detectable material or component is also disclosed in Patent No. 7,662,510, but in some embodiments, it can be 50 wt% or less, 40 wt% or less, 30 wt% or less, 20 wt% or less, 10 wt% or less, 5 wt% or less, or 1 wt% or less based on the total weight of the porous film or substrate to be used. In one embodiment, this additive is barium sulfate.

[0077] In some embodiments, the additive may include lithium halide. This lithium halide may be lithium chloride, lithium fluoride, lithium bromide, or lithium iodide. This lithium halide may be lithium iodide, which is ion-conductive and electrically insulating. In some examples, a material that is ion-conductive and electrically insulating can be used as part of a battery separator.

[0078] In some embodiments, the additive may include a polymer processing agent. As will be understood by those skilled in the art, a polymer processing agent or additive is added to improve the processing efficiency and quality of polymeric compounds. In some embodiments, the polymer processing agent may be an antioxidant, a stabilizer, a lubricant, a processing aid, a nucleating agent, a colorant, an antistatic agent, a plasticizer, or a filler.

[0079] In some embodiments, the additive may include a high-temperature melt index (HTMI) polymer. The HTMI polymer may be any HTMI polymer that does not conflict with the purposes of the present disclosure. In some examples, the HTMI polymer may be at least one selected from the group consisting of PMP, PMMA, PET, PVDF, aramid, syndiotactic polystyrene, polyimide, polyamide, and combinations thereof.

[0080] The additive may optionally contain an electrolyte. The electrolyte described herein may be any electrolyte that does not conflict with the objectives of the present disclosure. The electrolyte may be any additive typically added by battery manufacturers, particularly lithium battery manufacturers, to improve battery performance. The electrolyte should also be mixable, such as being miscible with the polymer used for the polymeric porous substrate or being compatible with the coating slurry. The miscibility of the additive can also be assisted or improved by coating or partially coating the additive. For example, exemplary electrolytes are disclosed in A Review of Electrolyte Additives for Lithium-Ion Batteries, J. of Power Sources, vol. 162, issue 2, 2006 pp. 1379-1394, which is hereby incorporated by reference in its entirety. In some embodiments, the electrolyte is a solid electrolyte interphase (SEI) improver, a cathode protector, a flame retardant additive, a LiPF6 salt stabilizer, an overcharge protector, an aluminum corrosion inhibitor, a lithium deposition agent or improver, or a solvation enhancer, an aluminum corrosion inhibitor, a wetting agent, and a thickener. In some embodiments, the electrolyte may have more than one property, such as being a wetting agent and a thickener.

[0081] Exemplary SEI improvers include VEC (vinyl ethylene carbonate), VC (vinylene carbonate), FEC (fluoroethylene carbonate), and LiBOB (lithium bis(oxalate) borate). Exemplary cathode protectants include N,N'-dicyclohexylcarbodiimide, N,N-diethylaminotrimethylsilane, and LiBOB. Exemplary flame retardant additives include TTFP (tris(2,2,2-trifluoroethyl) phosphate), fluorinated propylene carbonate, and MFE (methyl nonafluorobuyl ether). Exemplary LiPF6 salt stabilizers include LiF, TTFP (tris(2,2,2-trifluoroethyl) phosphite), 1-methyl-2-pyrrolidinone, fluorinated carbamate, and hexamethylphosphoramide. Exemplary overcharge protectants include xylene, cyclohexylbenzene, biphenyl, 2,2-diphenylpropane, and phenyl t-butyl carbonate. Exemplary lithium deposition improvers include AlI3, SnI2, cetyltrimethylammonium chloride, perfluoropolyether, and tetraalkylammonium chloride with a long alkyl chain. Exemplary ion solvation enhancers include 12-crown-4 and TPFPB (tris(pentafluorophenyl)). Exemplary Al corrosion inhibitors include borates such as LiBOB and LiODFB. Exemplary wetting agents and viscosity diluents include cyclohexane and P2O5.

[0082] In some embodiments, the electrolyte additive is stable in air or resistant to oxidation. The battery separator containing the electrolyte additive disclosed herein may have a lifespan of several weeks to several months, such as from one week to eleven months.

[0083] In some embodiments, the additive may include immiscible additives for energy dissipation. Immiscible means that the additive cannot be miscible with the polymer used to form the layer of the porous film or substrate containing the additive.

[0084] The substrate described in this specification may be MD stretched or TD stretched to make the substrate porous. In some examples, this substrate is made by performing TD stretching following the MD stretched substrate, or by performing MD stretching following the TD stretched substrate. In addition to continuous MD-TD stretching (with or without relaxation), this substrate may simultaneously undergo biaxial MD-TD stretching (with or without relaxation). Further, for the simultaneously or continuously MD-TD stretched porous substrate, subsequent stretching, relaxing, heat setting, or calendaring processes can be performed to reduce the thickness of the substrate, reduce the roughness, reduce the porosity ratio, increase the TD tensile strength, increase the uniformity, and / or reduce the TD splittiness.

[0085] In some embodiments, the substrate may contain pores having an average pore size of 0.01 nm to 1 μm, 0.01 μm to 1 μm, 0.02 μm to 1 μm, 0.03 μm to 1 μm, 0.04 μm to 1 μm, 0.05 μm to 1 μm, 0.06 μm to 1 μm, 0.07 μm to 1 μm, 0.08 μm to 1 μm, 0.09 μm to 1 μm, 0.1 μm to 1 μm, 0.2 μm to 1 μm, 0.3 μm to 1 μm, 0.4 μm to 1 μm, 0.5 μm to 1 μm, 0.6 μm to 1 μm, 0.7 μm to 1 μm, 0.8 μm to 1 μm, 0.9 μm to 1 μm, 0.01 μm to 0.9 μm, 0.01 μm to 0.8 μm, 0.01 μm to 0.7 μm, 0.01 μm to 0.6 μm, 0.01 μm to 0.5 μm, 0.01 μm to 0.4 μm, 0.01 μm to 0.3 μm, 0.01 μm to 0.2 μm, 0.01 μm to 0.1 μm, 0.01 μm to 0.09 μm, 0.01 μm to 0.08 μm, 0.01 μm to 0.07 μm, 0.01 μm to 0.06 μm, 0.01 μm to 0.05 μm, 0.01 μm to 0.04 μm, 0.01 μm to 0.03 μm, 1 μm, 0.9 μm, 0.8 μm, 0.7 μm, 0.6 μm, 0.5 μm, 0.4 μm, 0.3 μm, 0.2 μm, 0.1 μm, 0.09 μm, 0.08 μm, 0.07 μm, 0.06 μm, 0.05 μm, 0.04 μm, 0.03 μm, 0.02 μm, or 0.01 μm.

[0086] In an embodiment, the porous substrate is reduced in a controlled manner, for example, the thickness of such a drawn substrate such as a multi-layer porous substrate, and / or the breaking strength, longitudinal and / or transverse tensile strength, uniformity, wettability, coatability, runnability, compression, spring bag, flexure, permeability, thickness, pin removal force, mechanical strength, surface roughness, hot tip hole propagation and / or combinations thereof, etc. of such a drawn substrate such as a multi-layer porous substrate are improved in a controlled manner, and / or for manufacturing a unique structure, pore structure, material, substrate, base substrate, and / or separator, it may be manufactured using exemplary processes including a transverse drawing (regardless of the presence or absence of longitudinal relaxation) following longitudinal drawing and a subsequent calendar process and the subsequent calendar process.

[0087] In some examples, the TD tensile strength of the multi-layer substrate can be further improved by adding a calendar step after the TD drawing process. The calendar process typically requires heat and pressure that can reduce the thickness of the porous substrate. Performing the calendar process step can recover the decrease in the MD and TD tensile strengths due to TD drawing. Further, an increase is observed in the MD and TD tensile strengths due to the calendar process, so that the MD and TD tensile strength ratios become more balanced, which is beneficial to the overall mechanical performance of the multi-layer substrate.

[0088] In the calendaring process, uniform or non-uniform calendering conditions (such as the use of smooth rolls, rough rolls, patterned rolls, micro-patterned rolls, nano-patterned rolls, speed changes, temperature changes, pressure changes, humidity changes, double-roll steps, multiple-roll steps, or combinations thereof) can be provided to selectively compress the heat-sensitive material, to create improved, desirable or unique structures, properties and / or performance, to manufacture or control the resulting structures, properties and / or performance, and / or to use uniform or non-uniform heat and / or speed as in the same kind. In embodiments, a calendering pressure of 5 to 200 psi, a calendering temperature of 50 °C to 70 °C, and a line speed of 40 to 80 ft / min can be used. In some examples, high pressure can provide a thin separator and low pressure can provide a thick separator.

[0089] In some embodiments, the porous substrate or membrane described herein may comprise a coating located on the first surface, the second surface, or both the first and second surfaces of the porous substrate. As shown in FIGS. 1 and 2. In some embodiments, the coating may comprise a first layer and a second layer. In some examples, the first layer of the coating may be located on the first surface of the substrate, on the second surface of the substrate, or on both the first and second surfaces of the substrate. When the first layer is located on the first and / or second surfaces of the substrate, the second layer of the coating may be located on one or both of the first layers of the coating.

[0090] In some embodiments, the second layer of the coating may be located on the first surface of the substrate, on the second surface of the substrate, or on both the first and second surfaces of the substrate. When the second layer is located on the first and / or second surfaces of the substrate, the first layer of the coating may be located on one or both of the second layers of the coating.

[0091] In a further embodiment, the first layer of the coating may be located on one of the first or second surfaces of the substrate, and the second layer of the coating may be located on the other of the first or second surfaces of the substrate. In this embodiment, the first layer on one of the surfaces of the substrate may optionally be covered with the second layer, and the second layer on the other surface of the substrate may optionally be covered with the first layer, such that the first and second surfaces are arranged on opposite sides of the coating layer.

[0092] Furthermore, in other embodiments, the first layer may be located on both the first and second surfaces of the substrate, and only one of the two first layers of the substrate further covers the second layer of the coating. Similarly, in other examples, the second layer may be located on both the first and second surfaces of the substrate, and only one of the two second layers of the substrate further covers the first layer of the coating.

[0093] The first layer and the second layer may each have any thickness that is not inconsistent with the objectives of the present disclosure. In some cases, the first layer has a thickness of 10 nm to 20 μm, 500 nm to 15 μm, 500 nm to 10 μm, 500 nm to 5 μm, or 500 nm to 1 μm. The second layer has a thickness of 500 nm to 20 μm, 500 nm to 15 μm, 500 nm to 10 μm, 500 nm to 5 μm, or 500 nm to 1 μm. The thicknesses of the first layer and the second layer may be the same or different.

[0094] In another aspect, the method for preparing the coated separator described above includes coating one or both of the first surface, the second surface facing the opposite side, or the first and second surfaces of the porous substrate including the layer, the first layer, and / or the second layer.

[0095] According to one or more preferred possible processes, one or more strong solvents, acids, or the like are used to convert an insoluble polyimide into a soluble polyimide. The soluble polyimide is then mixed with a solvent and particles to form a coating slurry, which is coated onto a base film, dried, and the particles are then removed from the dried coating to form a base film or separator coated with a preferred porous polyimide.

[0096] According to one or more preferred possible processes, one or more strong solvents, acids, or the like are used to convert an insoluble polyimide into a soluble polyimide. The soluble polyimide is then mixed with a solvent and particles (or other pore-forming agents) to form a coating slurry, which is coated onto a base film, dried, and the particles (or other pore-forming agents) are then optionally removed from the dried coating to form a base film or separator coated with a preferred porous polyimide.

[0097] According to at least one embodiment, the coating (or coating slurry) and the base film or separator may be coextruded.

[0098] According to at least one embodiment, a coating or layer can be deposited or precipitated onto a base film or separator by vapor deposition, PVD, CVD, or laser sputtering, etc.

[0099] According to one or more preferred possible embodiments, a polyimide and / or polyamide-imide coating film configured for a high energy or high voltage charge type lithium battery, battery, cell, primary battery, secondary battery, capacitor, fuel cell, fabric, clothing, filter, and / or composite, and / or other uses, devices, and / or the like, a microporous base layer, membrane or film and A polyimide and / or polyamide-imide coating or layer, preferably a polymer layer, more preferably a polyole fin-based layer, and most preferably a dry-stretched polyolefin-based layer, on at least one surface of a microporous base layer, film or film, a polyimide and / or polyamide-imide coated film.

[0100] According to one or more preferred possible embodiments, a polyimide and / or polyamide-imide coated film, a microporous polymer layer, film or film and a polyimide and / or polyamide-imide coating or layer on at least one surface of the microporous polymer layer, a polyimide and / or polyamide-imide coated film.

[0101] According to one or more preferred possible embodiments, a battery, cell, primary battery, capacitor, fuel cell, fabric, clothing, filter, and / or composite, and / or other applications, devices and / or layers or components of the same kind, comprising or including the above polyimide and / or polyamide-imide coating layer, film or film.

[0102] According to one or more preferred possible embodiments, the polyimide coating or layer is at least partially covered by another coating or layer such as an adhesive or a pressure-sensitive coating.

[0103] According to one or more preferred possible embodiments, the separator further comprises at least one of its surfaces with another coating or layer such as an adhesive or a pressure-sensitive coating.

[0104] According to one or more preferred possible embodiments, the polyimide coating and / or the adhesive or pressure-sensitive coating contains or includes PVDF or a PVDF copolymer.

[0105] The present disclosure or invention preferably relates to a polyimide coating film, a separator film, or a separator for a lithium battery such as a high energy or high voltage rechargeable lithium battery, and a corresponding battery. The separator preferably includes a porous or microporous polyimide coating or layer on at least one surface of a microporous polymer layer, film, or sheet. The polyimide coating or layer may include other polymers, additives, fillers, or the like. The polyimide coating may be configured, for example, to provide oxidation resistance, prevent dendritic crystal growth, add dimensional and / or mechanical stability, reduce shrinkage, add high temperature performance (HTMI function), prevent electrical short circuit at temperatures above 200° C., and / or the like. The microporous polymer base layer may be configured to retain at least a liquid, gel, or polymer electrolyte, conduct ions, and / or block ion flow between the anode and cathode during thermal runaway (shutdown function). The polyimide-coated separator may be configured, for example, to separate multiple electrodes at high temperatures, provide oxidation resistance, prevent dendritic crystal growth, add dimensional stability, reduce shrinkage, add high temperature performance (HTMI function), prevent electrical short circuit at temperatures above 200° C., increase fracture strength, and / or block ion flow between the anode and cathode during thermal runaway (shutdown function). Although the use of a lithium secondary battery is preferred, the polyimide coating film of the present invention may be used as a layer or component of a battery, cell, primary battery, capacitor, fuel cell, fabric, clothing, filter, and / or composite, and / or other applications, devices, and / or the like.

[0106] The present invention may be embodied in other specific forms without departing from its spirit or essential attributes, and accordingly, reference should be made to the appended claims, figures, or specification as indicating the scope of the present invention.

Claims

1. A polyimide-coated separator for a high-energy or high-voltage rechargeable lithium battery, comprising: a microporous polymer layer, film or sheet; and a polyimide coating or layer on at least one surface of the microporous polymer layer. The polyimide-coated separator.

2. The separator according to claim 1, wherein the polyimide coating or layer provides oxidation resistance, inhibits dendritic crystal growth, adds dimensional stability, reduces shrinkage, adds high-temperature performance (HTMI function), prevents electrical short circuit at temperatures above 200 °C, and / or is compatible with those of the same kind.

3. The separator according to claim 1 or 2, wherein the microporous polymer layer is adapted to hold a liquid electrolyte, conduct ions, and / or block ion flow between the anode and cathode of a cell or battery during thermal runaway (shutdown function).

4. The separator according to any one of claims 1 to 3, wherein the polyimide coating or layer is porous, microporous, mesoporous, macroporous and / or nanoporous.

5. The separator according to claim 4, wherein the polyimide coating or layer is pore-formed by removing a plasticizer, pore-forming agent, and / or particles from a coating formulation comprising at least polyimide and at least one of a plasticizer, pore-forming agent, and / or particles.

6. The separator according to claim 5, wherein the polyimide coating or layer is pore-formed by removing particles from a coating formulation comprising at least polyimide and particles.

7. The particles are silica, calcium carbonate, sodium chloride, kaolin, barium sulfate, SiO 2 , Al 2 O 3 , CaCO 3 , TiO 2 , SiS 2 , SiPO 4 , salts, NaCl, and / or The separator according to claim 5 or 6, which is selected from the group consisting of its mixture or blend.

8. The separator according to any one of claims 5 to 7, wherein the particles are removed by one or more solvents.

9. The one or more solvents are water, oil, hydrocarbon, ester, ether, alcohol, freon, N,N-methylpyrrolidinone (NMP), γ-butyrolactone, formula R 1 R 2 N-SO 2 -NR 3 R 4 is a sulfamide of the formula, wherein R1, R 2 , R 3 and R 4 are alkyl having 1 to 6 carbon atoms and / or oxyalkyl having 1 to 6 carbon atoms, a sulfamide, and / or a blend or combination thereof, the separator according to claim 8.

10. The separator according to any one of claims 5 to 7, wherein the particles are solvent-soluble particles.

11. The separator according to claim 5, wherein the polyimide coating or layer is pore-formed by removing a plasticizer from a coating formulation comprising at least polyimide and a plasticizer.

12. The separator according to claim 5, wherein the polyimide coating or layer is pore-formed by removing a pore-forming agent from a coating formulation comprising at least polyimide and a pore-forming agent.

13. The separator according to any one of claims 1 to 12, wherein the polyimide coating or layer may contain other polymers, additives, fillers, and / or the like of the same kind.

14. The separator according to any one of claims 1 to 13, wherein the polyimide of the polyimide coating or layer is polyimide, copolyimide, soluble polyimide, solvent-soluble polyimide, water-soluble polyimide, soluble copolyimide, solvent-soluble copolyimide, water-soluble copolyimide, and combinations thereof, mixtures thereof or blends thereof.

15. The separator according to any one of claims 1 to 14, wherein the polyimide of the polyimide coating or layer is copolyimide.

16. The separator according to any one of claims 1 to 15, wherein the polyimide coating or layer is a copolyimide coating or layer.

17. The separator according to any one of claims 1 to 15, wherein the polyimide coating or layer is a polyamide-imide or fluorinated polyimide coating or layer.

18. The separator according to any one of claims 5 to 10, wherein the particles contain 20% to 80% by weight of the mixture of the polyimide and the particles before being removed.

19. The separator according to any one of claims 1 to 18, wherein the microporous polymer layer is a polyolefin-based membrane.

20. The separator according to claim 19, wherein the polyolefin-based membrane is a polypropylene and / or polyethylene membrane.

21. The separator according to claim 19, wherein the polyolefin-based membrane has a porosity in the range of 20% to 80%, an average pore size in the range of 0.02 to 1.0 μm, and a Gurley number in the range of 5 to 300 seconds.

22. The separator according to claim 5, 6 or 7, wherein the particles have an average particle diameter in the range of 0.001 to 10 μm.

23. An anode, a cathode, the separator according to any one of claims 1 to 22 disposed between the anode and the cathode, An electrolyte that ionically communicates with the anode and the cathode through the separator, A high-energy or high-voltage rechargeable lithium battery comprising the same.

24. An anode containing lithium metal, or a lithium alloy, or a mixture of lithium metal and / or lithium alloy and another substance, a cathode, a separator according to any one of claims 1 to 23 disposed between the anode and the cathode, an electrolyte that ionically communicates with the anode and the cathode through the separator, and a high-energy rechargeable lithium battery comprising the same. **Claim 2** A polyimide coating film suitable for high-energy or high-voltage rechargeable lithium batteries, batteries, cells, primary batteries, secondary batteries, capacitors, fuel cells, fabrics, filters, and / or composites, and / or other uses, devices, and / or layers or components of the same kind, comprising a microporous base layer, membrane or film, and a polyimide coating or layer, preferably a polymer layer, more preferably a polyolefin-based layer, most preferably a dry-stretched process polyolefin-based layer, on at least one surface of the microporous base layer, membrane or film. A polyimide coating film comprising the same. **Claim 26** A polyimide and / or polyamide-imide coating film suitable for high-energy or high-voltage rechargeable lithium batteries, batteries, cells, primary batteries, secondary batteries, capacitors, fuel cells, fabrics, clothes, filters, and / or composites, and / or other uses, devices, and / or layers or components of the same kind, comprising a microporous base layer, membrane or film, and a polyimide and / or polyamide-imide coating or layer, preferably a polymer layer, more preferably a polyolefin-based layer, most preferably a dry-stretched process polyolefin-based layer, on at least one surface of the microporous base layer, membrane or film. A polyimide and / or polyamide-imide coating film comprising the same. **Claim 27** A microporous polymer layer, membrane or film, and a polyimide and / or polyamide-imide coating or layer on at least one surface of the microporous polymer layer. A polyimide and / or polyamide-imide coating film comprising the same. **Claim 28** A battery, cell, primary battery, capacitor, fuel cell, fabric, clothes, filter, and / or composite, and / or other uses, devices and / or layers or components of the same kind, comprising or including the polyimide and / or polyamide-imide coating layer, membrane or film according to claim 27. **Claim 29** The separator according to any one of claims 1 to 15, wherein the polyimide coating or layer is at least partially covered by another coating or layer such as an adhesive or a pressure-sensitive adhesive coating.

30. The separator according to any one of claims 1 to 15, further comprising at least one surface thereof with another coating or layer such as an adhesive or a pressure-sensitive adhesive coating.

31. The separator according to any one of claims 29 and 30, wherein the polyimide coating and / or the adhesive or pressure-sensitive adhesive coating contains or comprises PVDF or a PVDF copolymer.

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