Improved Coated Battery Separator and Battery

Abstract

Disclosed herein are coated separators or porous membranes containing a coating on one or two sides of the separator membrane or porous membrane. The coating may contain at least one of an adhesive, a shutdown agent, and a binder. The coating containing these components does not contain any inorganic or organic heat-resistant materials, including ceramic materials, or contains a small amount of inorganic or organic heat-resistant materials, including ceramic materials. The separator may be one that does not have shutdown capability itself. For example, the separator membrane of the separator may be a single-layer separator membrane made of polypropylene. Also disclosed herein are battery cells, secondary batteries, and capacitors containing at least one of the coated separators disclosed herein.

Description

Technical Field

[0001] This application is directed, inter alia, to an improved battery separator having improved safety, improved ease of handling, and improved ease of use in battery manufacturing.

Background Art

[0002] Due to increasing performance specifications, safety specifications, manufacturing requirements, and / or environmental concerns, the development of new and / or improved coating compositions for battery separators is desirable.

[0003] One of the main safety issues regarding lithium-ion batteries is thermal runaway. Abuse conditions, such as overcharging, over-discharging, and internal short circuits, can cause battery temperatures that far exceed the intended operating temperature of the battery, for example, as used by battery manufacturers. Examples of tests for mimicking abuse conditions include, but are not limited to, nail penetration tests and hot box tests. For example, the shutdown of the battery between the anode and the cathode during a thermal runaway event, for example, the cessation of the ion flow across the separator, is a safety mechanism used to prevent thermal runaway. Separators in at least certain lithium-ion batteries must be capable of shutting down at a temperature at least slightly lower than the temperature at which thermal runaway occurs while still retaining their mechanical properties. For example, a faster shutdown at a lower temperature and for a longer duration is highly desirable so that the user or device has more time to stop the system.

[0004] Celgard's U.S. Patent No. 5,952,120, which is hereby incorporated by reference in its entirety, discloses a shutdown three-layer separator. This separator exhibits shutdown, at least in part, due to its inner polyethylene layer. The polyethylene melts at a temperature near the melting point of polyethylene to close the pores of the separator. However, some separators do not have the ability to shut down on their own at low temperatures (e.g., below about 135 °C). For example, a single-layer separator made of polypropylene may not have this ability. Therefore, it is also desirable to provide a low-temperature shutdown ability to separators that may not have such a shutdown ability on their own.

[0005] As the market increasingly demands thinner separators, the ability to handle these very thin separators becomes increasingly important. Therefore, the construction of a separator for easier handling is highly desirable.

Summary of the Invention

Problems to be Solved by the Invention

[0006] As the demand for thinner separators increases, the ease with which a battery separator can be used to manufacture a battery cell is also important. Therefore, the construction of a separator that can be easily used to manufacture a wide variety of different battery cell types is highly desirable.

Means for Solving the Problems

[0007] In one aspect, a coated separator or a coated porous membrane is described herein. The coated separator or the coated porous membrane includes, consists of, or consists essentially of at least one coating selected from the group consisting of a separator or a porous membrane, and an adhesive, a shutdown agent, and a binder. The coating, in some embodiments, does not contain any inorganic or organic heat-resistant particles, but in other embodiments, the coating may contain a small amount of inorganic and / or organic heat-resistant particles (less than 10% or less than 5% of the total solids). In some embodiments, the coated separator or the coated porous membrane may have another coating that includes, consists of, or consists essentially of more than a small amount of ceramic or inorganic or organic heat-resistant particles. This coating may be provided directly on top of a layer that does not contain more than a small amount of ceramic or organic or inorganic heat-resistant particles. However, a layer that includes, consists of, or consists essentially of at least one of an adhesive, a shutdown agent, and a binder does not contain more than a small amount of ceramic or organic or inorganic heat-resistant particles.

[0008] In some embodiments, the coating may comprise, consist of, or consist essentially of an adhesive. In some embodiments, the coating may comprise an adhesive and a binder. The adhesive may comprise, consist of, or consist essentially of at least one selected from the group of wet adhesives and dry adhesives. The wet adhesive may comprise, consist of, or consist essentially of PVDF, an acrylic polymer, or a combination thereof. The dry adhesive may comprise, consist of, or consist essentially of a dry adhesive polymer comprising PVDF-HFP copolymer or acrylic having a glass transition temperature of less than 100°C, preferably between 30°C and 80°C. The adhesive may comprise, consist of, or consist essentially of the dry adhesive alone, the wet adhesive alone, or both the dry adhesive and the wet adhesive.

[0009] In some embodiments, the coating may comprise, consist of, or consist essentially of a shutdown agent. In some embodiments, the coating may comprise a shutdown agent and a binder. The shutdown agent may comprise, consist of, or consist essentially of beads or particles made of a polymer having a melting point of about 100°C to about 140°C. In certain embodiments, PE beads having a melting point of 100°C to 140°C may be used. In some embodiments, the shutdown agent may comprise, consist of, or consist essentially of at least one selected from the group consisting of beads or particles made of a polymer having a melting point of about 130°C to about 140°C; beads or particles made of a polymer having a melting point of about 80°C to about 130°C; beads or particles having a melting point of 140°C to 220°C, and combinations thereof.

[0010] In some embodiments, the coating may comprise, consist of, or consist essentially of an adhesive and a shutdown agent. In some embodiments, the coating may comprise, consist of, or consist essentially of an adhesive, a shutdown agent, and a binder. The adhesive may comprise a dry adhesive alone, a wet adhesive alone, or both wet and dry adhesives.

[0011] The coated separator or the coated porous membrane may be a separator with one side coated, a porous membrane with one side coated, a separator with two sides coated, or a porous membrane with two sides coated. In the separator or porous membrane with two sides coated, one or both sides may comprise the coating described herein, or one side may comprise the coating described herein and the other side may comprise a different coating. The different coating may be, for example, a ceramic coating, a polymer coating, etc. An exemplary separator or porous membrane with one side and two sides coated is shown in FIG. 1.

[0012] In some embodiments, the separator of the coated separator may be one that does not have a shutdown function at a temperature of 150°C or less than 140°C without the coating. In some embodiments, the separator without a shutdown function is a dry process separator. In some embodiments, the separator is a separator made of or consisting essentially of polypropylene. In some embodiments, the separator is a single-layer polypropylene separator.

[0013] In some embodiments, the porous membrane of the coated porous membrane may be a microporous, macroporous, or mesoporous porous membrane. The porous membrane may be a porous membrane formed by a dry process.

[0014] In another aspect, a battery cell comprising at least one coated separator described herein is described. The cell may be at least one selected from a cylindrical cell, a pouch cell, a prismatic cell, a wound cell, a folded cell, a wrapping cell, a pocket cell or a stacked cell.

[0015] In another aspect, a secondary battery comprising at least one coated separator described herein is described.

[0016] In another aspect, a capacitor comprising at least one of the coated separators described herein is described.

[0017] In one aspect, a coated battery separator is described herein. The coated separator has at least one coating that does not contain any ceramic or heat-resistant particles and comprises, consists of, or consists essentially of an adhesive and a shutdown agent. In some embodiments, the coating may consist of an adhesive and a shutdown agent. In some embodiments, the coating may consist essentially of an adhesive, a shutdown agent, and an optional binder. In some embodiments, the coating may comprise an adhesive, a shutdown agent, and an optional binder. In such embodiments, the coating may contain other things, but ceramic or inorganic or organic heat-resistant particles in an amount less than a small amount (less than 10% of the total solids) may be added. In some embodiments, the coating may not contain ceramic, or organic, or organic heat-resistant particles.

[0018] In some embodiments, the coated separator may have another coating containing, consisting of, or consisting essentially of ceramic or inorganic or organic heat-resistant particles in excess of a small amount, but the layer containing, consisting of, or consisting essentially of an adhesive, a shutdown agent, and an optional binder does not contain ceramic or organic or inorganic heat-resistant particles, preferably nanoparticles, in excess of a small amount. For example, the ceramic coating may be provided on the side of the separator or membrane opposite to the coating of the present invention, or may be provided directly on top of the coating of the present invention. The term ceramic coating is well understood in the field of battery separators, particularly in the field of secondary lithium battery separators, and has 50% or more, 75% or more, 90% or more, or 95% or more ceramic particles by volume or weight, and, respectively, 50% or less, 25% or less, 10% or less, or 5% or less binder or polymer matrix by volume or weight, and typically includes ceramic particles in a binder or polymer matrix (e.g., made using an organic solvent PVDF binder or an aqueous acrylic binder and alumina or boehmite particles). Today, many typical ceramic coatings have a low binder addition, with more than 80%, more than 90%, or more than 95% or more ceramic by weight, and, respectively, less than 20%, less than 10%, or less than 5% binder or matrix by weight (high ceramic content and low binder or polymer matrix content). In some embodiments, the coating may contain, consist of, or consist essentially of an adhesive, a shutdown agent, an optional binder, and a small amount of additional components. For example, the additional component may be at least one selected from the group of antistatic agents, and the antistatic agent may contain inorganic or ceramic particles, such as carbon black, alumina, etc.

[0019] In some embodiments, the adhesive may comprise, consist of, or consist essentially of at least one selected from the group consisting of dry adhesives, wet adhesives, and combinations of the two. In some embodiments, the adhesive may comprise, consist of, or consist essentially of a wet adhesive. In some embodiments, the adhesive may comprise, consist of, or consist essentially of a dry adhesive. In some embodiments, the adhesive may comprise, consist of, or consist essentially of a wet adhesive and a dry adhesive. In some embodiments, the adhesive may comprise, consist of, or consist essentially of PVDF.

[0020] In some embodiments, the shutdown agent may comprise, consist of, or consist essentially of beads or particles made of a polymer having a melting point of about 100°C to about 140°C. In some embodiments, the shutdown agent may comprise, consist of, or consist essentially of PE beads. In some embodiments, the shutdown agent may comprise, consist of, or consist essentially of beads or particles made of a polymer having a melting point of about 130°C to about 140°C; beads or particles made of a polymer having a melting point of about 80°C to about 130°C; beads or particles having a melting point of 140°C to 220°C, and combinations thereof. The beads or particles may have an average particle size with a particle diameter of 0.5 to 3 microns.

[0021] In some embodiments, the separator is a separator made of or consisting essentially of polypropylene. In some embodiments, a separator made of or consisting essentially of polypropylene is a single-layer and / or dry-process separator. In some embodiments, the separator is a separator without a coating containing, consisting of, or consisting essentially of an adhesive and a shutdown agent and having no shutdown ability without the coating. In some embodiments, a separator without a coating and having no shutdown ability is a dry-process separator.

[0022] In some embodiments, the coating may be on one side of the separator or the porous film, and in other embodiments, it may be on two sides of the separator or the porous film. Occasionally, the separator or the porous film may contain another coating that does not contain ceramic or heat-resistant particles.

[0023] In another aspect, a coated separator comprising a microporous film and a coating is described herein. The coated separator shuts down in some embodiments before shrinking by more than 15%, more than 12%, or more than 10% in at least the longitudinal or transverse dimension (length and / or width). In some embodiments where the coated separator shuts down before shrinking by more than 15%, more than 12%, or more than 10%, such temperature is less than 130°C, less than 125°C, less than 120°C, less than 115°C, or less than 110°C.

[0024] In some embodiments, the coating of the coated separator may comprise, consist of, or consist essentially of polyethylene and a binder. In some embodiments, the coating may further comprise, consist of, or consist essentially of inorganic microparticles in an amount of 10% or less, or 5% or less of the total solids during coating. The inorganic microparticles may comprise, consist of, or consist essentially of metal oxides having a particle size D50 of less than 500 nm, less than 250 nm or less, or less than 200 nm or less. In some embodiments, the metal oxide may comprise, consist of, or consist essentially of alumina. The coating may be on one or both sides of the porous or microporous film and may be applied directly or indirectly (i.e., via an intervening layer) to the porous or microporous film. For example, the intervening layer may be a ceramic layer in some embodiments.

[0025] In some embodiments, the porous or microporous film may be a single-layer film. The single-layer film may comprise, consist of, or consist essentially of polypropylene. The microporous film may have an average porosity of greater than 30%. The microporous film may have an average pore size of greater than 0.03 microns, greater than 0.04 microns, greater than 0.045 microns, or greater. In some embodiments, the microporous film may be a two-layer, three-layer, or multi-layer microporous film.

[0026] In another aspect, a secondary battery comprising at least one coated battery separator described herein is described.

[0027] In another aspect, a capacitor comprising a coated battery separator of the coated porous membrane described herein is described.

[0028] In another aspect, a composite is described that includes a coated battery separator of a coated porous membrane as described herein, having a further layer directly on top of the coating. In such embodiments, the coating may comprise, consist of, or consist essentially of an adhesive. The coating may comprise, consist of, or consist essentially of an adhesive and a binder. The coating may comprise, consist of, or consist essentially of an adhesive, a binder, and a small amount of inorganic or organic particles. The coating may be an aqueous or water-based coating. The further coating provided directly on top of the coating may be a ceramic coating, a polymer coating, a coating comprising, consisting of, or consisting essentially of an electrode material, a coating comprising, consisting of, or consisting essentially of a solid electrolyte material, a metal coating, a metal layer, a metal-containing coating, and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0029]

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Best Mode for Carrying Out the Invention

[0030] A coated separator or a coated porous membrane is described herein. In preferred embodiments, the coated separator or the coated porous membrane has a coating comprising, consisting of, or consisting essentially of at least one selected from the group consisting of an adhesive, a shutdown agent, and a binder. The coating does not contain a ceramic or heat-resistant material, or contains only a small amount of such a material. In some preferred embodiments, the coating may include an adhesive, a shutdown agent, and one or more additional components. In other preferred embodiments, the coating may consist of or consist essentially of an adhesive and a shutdown agent. In some embodiments, the coating may be one of the following combinations: an adhesive; an adhesive and a binder; a shutdown agent; a shutdown agent and a binder; a shutdown agent and an adhesive; and a shutdown agent, an adhesive, and a binder. In any of the above combinations, the adhesive may include: a wet adhesive or only a wet adhesive; a dry adhesive or only a dry adhesive; or a combination of at least one wet adhesive and at least one dry adhesive.

[0031] The coating may be provided on one or both sides of the separator or the porous membrane. In some preferred embodiments where the coating is provided on both sides, the coating is provided on two opposing sides of the separator or the porous membrane. This is shown in Figure 1.

[0032] In some embodiments, the coated separator or coated porous membrane described herein may include, consist of, or consist essentially of a coating other than a coating that includes at least one selected from an adhesive, a shutdown agent, and a binder. For example, a separator coated on both sides may have, on one side, a coating that includes at least one selected from an adhesive, a shutdown agent, and a binder, consists of, or consists essentially of, and, on the other side, a different coating. For example, the different coating may be a ceramic coating.

[0033] Coating The coatings described herein may comprise, consist of, or consist essentially of at least one of (1) a shutdown agent and (2) an adhesive, and (3) a binder. In some preferred embodiments, the coating does not contain ceramic or other heat-resistant inorganic or organic materials. In some embodiments, the coating may further comprise, consist of, or consist essentially of a small amount (less than about 10% or less than 5% of the total solids), for example, for the purpose of imparting an antistatic effect, of a ceramic or other heat-resistant organic or inorganic material. The coatings described herein may contain some amount of ceramic or other organic or inorganic heat-resistant material, but the coating is not a typical ceramic coating and may contain 90% or more or 95% or more by weight of a ceramic or other inorganic or organic heat-resistant material. In some embodiments, the coating may comprise: a shutdown agent; a shutdown agent and a binder; an adhesive; an adhesive and a binder; a shutdown agent and an adhesive; or a shutdown agent, an adhesive, and a binder. In any of the above embodiments, the adhesive may comprise, consist of, or consist essentially of a wet adhesive or only a wet adhesive; a dry adhesive or only a dry adhesive; or at least one dry adhesive and at least one wet adhesive.

[0034] In some other embodiments, the coating may comprise, consist of, or consist essentially of a polyethylene shutdown agent, or a polyethylene shutdown agent with a binder and optionally inorganic microparticles. The polyethylene is not overly limited and may include any polyethylene, particularly those with a lower melting temperature as described herein. The binder is not overly limited and may be any binder described herein. The inorganic microparticles are not overly limited and may be any of, or include, inorganic materials such as those described herein. The inorganic microparticles may be nanoparticles and may have an average particle size of less than about 500 nm, less than 450 nm, less than 400 nm, less than 350 nm, less than 300 nm, less than 250 nm, less than 225 nm, less than 200 nm, less than 175 nm, less than 150 nm, less than 125 nm, or smaller. In some embodiments, the particle size may be greater than 250 nm and up to 1,000 nm. A smaller particle size is advantageous in some embodiments described herein, particularly with respect to the shutdown coatings and some of the adhesion coatings described herein. For example, without wishing to be bound by any particular theory, inorganic microparticles are thought to be preferably present in coatings containing a shutdown agent because the shutdown agent may flow more easily to block the pores of the separator or porous membrane, resulting in shutdown. In some embodiments, the inorganic microparticles may comprise, consist of, or consist essentially of a metal oxide. In some embodiments, the metal oxide may be alumina or aluminum oxide. In some embodiments, the metal oxide may be another metal oxide other than alumina, including those disclosed herein.The inorganic microparticles may be present in an amount of less than 10% of the total solids of the coating, less than 9% of the total solids of the coating, less than 8% of the total solids of the coating, less than 7% of the total solids of the coating, less than 6% of the total solids of the coating, less than 5% of the total solids of the coating, less than 4% of the total solids of the coating, less than 3% of the total solids of the coating, less than 2% of the total solids of the coating, or less than 1% of the total solids of the coating.

[0035] The coating may have a thickness of 0.5 to 10 microns, 0.5 to 9 microns, 0.5 to 8 microns, 0.5 to 7 microns, 0.5 to 6 microns, 0.5 to 5 microns, 0.5 to 4 microns, 0.5 to 3 microns, or 0.5 to 2 microns. In some preferred embodiments, the coating may be about 1 to about 2 microns thick. In some embodiments, the coating may be a single layer.

[0036] The coating may be provided using any known method. This may be formed by a coextrusion process in which the separator and the coating are coextruded together.

[0037] In some preferred embodiments, the coating is provided directly on the surface of the separator, but in some embodiments, an intervening layer may be provided between the separator and the coating. For example, FIG. 9 shows an example having an intervening ceramic layer. Another layer or other layers may be provided on top of the coating. For example, a layer containing inorganic or organic heat-resistant particles may be provided on top of the layer. Further, a ceramic layer, a layer containing an electrode material, a layer containing a solid electrolyte material, a metal layer, a metal-containing layer, etc. may be provided directly on top of the coating. This is shown in FIG. 16. In FIG. 16, the coating is preferably an adhesive or tacky coating, but the coating may contain a shutdown agent and / or organic or inorganic particles including nanoparticles.

[0038] The size, shape, chemical composition, etc. of these heat-resistant particles are not very limited. The heat-resistant particles may include organic materials, inorganic materials, such as ceramic materials, or composite materials containing both inorganic and organic materials, two or more organic materials, and / or two or more inorganic materials.

[0039] In some embodiments, heat resistance means that the particles may include composite materials composed of two or more different materials, and the materials constituting the particles do not undergo substantial physical changes, such as deformation, at a temperature of 200 °C. Exemplary materials include aluminum oxide (Al2O3), silicon dioxide (SiO2), graphite, and the like.

[0040] Non-limiting examples of inorganic materials that can be used to form the heat-resistant particles disclosed herein are as follows: iron oxide, silicon dioxide (SiO2), aluminum oxide (Al2O3), boehmite (Al(O)OH), zirconium dioxide (ZrO2), titanium dioxide (TiO2), barium sulfate (BaSO4), barium titanate oxide (BaTiO3), aluminum nitride, silicon nitride, calcium fluoride, barium fluoride, zeolite, apatite, kaolin, mullite, spinel, olivine, mica, tin dioxide (SnO2), indium tin oxide, transition metal oxides, graphite, carbon, metals, and any combination thereof.

[0041] Non-limiting examples of organic materials that can be used to form the heat-resistant particles disclosed herein are as follows: polyimide resin, melamine resin, phenol resin, polymethyl methacrylate (PMMA) resin, polystyrene resin, polydivinylbenzene (PDVB) resin, carbon black, graphite, and any combination thereof.

[0042] The heat-resistant particles may be circular, irregular in shape, flakes, etc. The average particle size of the heat-resistant material is in the range of 0.01 to 5 microns, 0.03 to 3 microns, 0.01 to 2 microns, 0.5 to 3 microns, etc.

[0043] In some preferred embodiments, the coating may be an aqueous or water-based coating. "Aqueous" means that the coating is formed from a coating slurry in which the solvent is only water or water and alcohol or other non-organic water-soluble solvents. For example, an aqueous or water-based coating may contain a solvent that is water and up to 50% alcohol or non-organic water-soluble solvents, such as PVA. In some embodiments, the coating may be a solvent-based coating. A solvent-based coating is formed from a slurry in which the solvent is an organic solvent. Sometimes, the solvent is present with the binder used. After being formed from the coating slurry, most of the solvent is removed from the coating.

[0044] (1) Shutdown agent The shutdown agent is not very limited. In some embodiments, the shutdown agent can impart at least one of the following functions: (1) providing a low-temperature (e.g., less than 135°C) shutdown ability to a separator that does not have a low-temperature shutdown ability without the coating, (2) lowering the shutdown start temperature of a separator having a low-temperature shutdown ability, and (3) expanding the shutdown window of a separator having a low-temperature shutdown ability. All of the shutdown agents described herein can be used in separators with or without a low-temperature shutdown ability, even if a particular application may be more preferred than others.

[0045] Regarding the use of the shutdown agent disclosed herein, it may be preferable to use a shutdown agent that provides low-temperature shutdown in a separator that does not exhibit a low-temperature shutdown function by itself. However, a shutdown agent that lowers the shutdown start temperature or expands the shutdown window may be used to impart an expanded shutdown window. Examples of separators that exhibit a low-temperature shutdown function can be found in U.S. Patent No. 5,952,120 to Celgard, which is hereby incorporated by reference in its entirety. In this document, shutdown is at least partially imparted by melting of the polyethylene-containing intermediate layer of the three layers. In such a shutdown three-layer, since the PE shutdown also contributes to the strength of the film, there is typically a lower limit to the melting point and molecular weight of the polyethylene used. Lower molecular weights (and thus lower melting points) are typically not used because they do not impart the same mechanical strength as higher molecular weight (and higher melting point) polyethylene. However, when shutdown is imparted in a coating when done here, polyethylene of lower molecular weight (and thus lower melting point) can be used as a shutdown agent for coatings that do not necessarily impart mechanical strength to the separator. The coatings herein can also be imparted with a "double shutdown" effect where shutdown can begin at a lower shutdown agent melting point than that of the polymer used in the shutdown layer of the shutdown three-layer, as disclosed in U.S. Patent No. 5,952,120 to Celgard®. By imparting a lower shutdown ability to the separator, the safety of the battery in which the separator is used is improved. For example, thermal runaway can be better prevented.

[0046] In some embodiments, the shutdown agent may be in the form of particulate matter or beads. The particulate matter or beads may have an average particle size of 0.1 to 3 microns, 0.1 to 2 microns, 0.1 to 1.5 microns, 0.1 to 1.0 microns, 0.5 to 3.0 microns, or 0.1 to 0.5 microns. The particles or beads may be shaped symmetrically, asymmetrically, spherically, or non-spherically.

[0047] In embodiments where the shutdown agent can impart low-temperature shutdown ability to a separator that does not have low-temperature shutdown ability without a coating, the shutdown agent may comprise, consist of, or consist essentially of a polymer having a melting point of about 135°C or lower. In some embodiments, the polymer may have a melting point of less than about 130°C, less than about 125°C, less than about 120°C, less than about 115°C, less than about 110°C, less than about 105°C, less than about 100°C, less than about 95°C, or less than about 90°C. In some embodiments, the polymer may have a melting point in the range of 80°C to 135°C. In some embodiments, the shutdown agent may comprise, consist of, or consist essentially of polymer beads. In some preferred embodiments, the shutdown agent may comprise, consist of, or consist essentially of polyethylene beads.

[0048] In embodiments where the shutdown agent lowers the shutdown start temperature of the separator, the separator exhibits a shutdown profile similar to that shown in FIG. 2.

[0049] In such an embodiment, the shutdown agent has a melting point lower than a value within 1 or 2 or 3 degrees of the shutdown start temperature, or the shutdown start temperature of the separator itself. For example, the shutdown agent may include, consist of, or consist essentially of a polymer having a melting point lower than a value starting from 80 °C and lower than the shutdown start temperature measured for the separator itself, i.e., without coating. Alternatively, the shutdown agent may include, consist of, or consist essentially of a polymer having a melting point up to a temperature within 1, or 2, or 3 degrees of the shutdown start temperature of the separator itself. Exemplary materials may include waxes, oligomers, polyethylene (PE), such as particles or beads including low-density PE, etc. These particles may or may not be coated, or may be partially coated.

[0050] In an embodiment where the shutdown agent expands the shutdown window of a separator having shutdown ability, the separator shows the shutdown window shown in FIG. 2. In such an embodiment, the shutdown agent may include a polymer having a melting point higher than the shutdown temperature. For example, in these embodiments, the shutdown agent may have a melting temperature above 135 °C. For example, the shutdown agent may have a melting point in the range of 140 °C to 220 °C, sometimes in the range of 150 °C to 200 °C, sometimes in the range of 160 °C to 190 °C, sometimes in the range of 170 °C to 180 °C, etc.

[0051] (2) Adhesive The adhesives described herein are not overly limited. In some embodiments, the adhesive is at least one selected from the group consisting of wet adhesives, dry adhesives, and combinations thereof.

[0052] In some embodiments, the adhesive is in the form of beads or particles having an average particle size of 0.1 to 3 microns, 0.1 to 2 microns, 0.1 to 1.5 microns, 0.1 to 1.0 microns, 0.5 to 3 microns, or 0.1 to 0.5 microns. The beads or particles may be shaped spherically, symmetrically, or asymmetrically.

[0053] In some preferred embodiments, the wet adhesive may comprise, consist of, or consist essentially of a wet adhesive polymer. The wet adhesive polymers described herein are not so limited and may be any polymer that absorbs an electrolyte, expands or increases in size when absorbing the electrolyte, and / or becomes gel-like when absorbing the electrolyte. The electrolyte may be any electrolyte suitable for use in a secondary battery, including but not limited to electrolytes in which the solvent is DEC, PC, DMC, EC, or a combination thereof. The wet adhesive polymer also increases the adhesion of the coating to the anode or cathode of the secondary battery when wetted by the electrolyte.

[0054] In some embodiments, the wet adhesive polymer may comprise, consist of, or consist essentially of a fluoropolymer. In some embodiments, the fluoropolymer is PVDF, for example, PVDF-HFP. The HFP content of PVDF-HFP may be 1 to 50 wt% based on the total weight of the polymer. In some embodiments, it may be 1 to 40 wt%, 1 to 30 wt%, 1 to 20 wt%, 1 to 15 wt%, 1 to 10 wt%, or 1 to 5 wt%.

[0055] In some embodiments, the wet adhesion polymer may include, consist of, or consist essentially of methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, sec-butyl (meth)acrylate, pentyl (meth)acrylate, 2-ethylbutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, lauryl (meth)acrylate, tetradecyl (meth)acrylate, polyvinylidene difluoride (PVDF), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF:HFP), polytetrafluoroethylene (PTFE), polyethylene oxide (PEO), poly(vinyl alcohol) (PVA), polyacrylonitrile (PAN), polyacrylamide, polyvinyl acetate, polyvinyl pyrrolidone, polytetraethylene glycol diacrylate, polypropylene (PP) including isotactic PP, high density PP, ultra high molecular weight PP, low density PP, polyethylene (PE) including high density PE, ultra high molecular weight PE, low density PE, polyvinyl acetate, polyvinyl chloride, bisphenol-A polycarbonate (BPA-PC), cyclo-olefinic copolymer (COC), polysulfone (PSF), polyetherimide (PEI), polyurethane, acrylonitrile butadiene styrene (ABS), any copolymer of the foregoing, or any combination thereof.

[0056] The use of the wet adhesion polymer can be useful in batteries where adhesion to the electrodes is important.

[0057] In some preferred embodiments, the adhesive is, consists of, or consists essentially of the wet adhesion polymer described herein. In some preferred embodiments, PVDF is the wet adhesion polymer. In some embodiments, the wet adhesion polymer is an acrylic polymer.

[0058] In some preferred embodiments, the dry adhesive may comprise, consist of, or consist essentially of a dry adhesive polymer. The dry adhesive polymers described herein are not highly limited and can be any polymer that imparts high or low tack to a coating. A coating with high tack is more difficult to separate after contacting another surface to which a bond has been formed. A coating with lower tack is more easily separated and deposited after contacting another surface to which a bond has been formed. A tacky coating can be beneficial, for example, for battery separators used in stacked or prismatic battery cells. This helps prevent movement of the separator once in a suitable position in the cell.

[0059] The dry adhesive polymers described herein can be characterized by their glass transition temperature. In some embodiments, the dry adhesive polymer has a glass transition temperature of less than 100°C, less than 90°C, less than 80°C, less than 70°C, less than 60°C, less than 50°C, less than 40°C, less than 30°C, or less than 20°C. The minimum glass transition temperature can be 20°C, 10°C, 5°C, or 0°C. Preferably, in some embodiments, the glass transition temperature can be from 20°C to 100°C, or from 20°C to 70°C, or from 25°C to 100°C. In some embodiments, the dry adhesive polymer has a glass transition temperature of less than 100°C, less than 90°C, less than 80°C, or less than 70°C. In some preferred embodiments, the glass transition temperature of the dry adhesive polymer is between 30°C and 80°C, between 40°C and 70°C, between 40°C and 65°C, between 45°C and 60°C, between 45°C and 55°C, or between 45°C and 50°C.

[0060] Some non-limiting examples of the dry adhesive polymer may be PVDF-HFP copolymers or acrylics having the glass transition temperature described above. In some embodiments, the HFP content in PVDF-HFP may be 1-50%, 1-40%, 1-30%, 1-20%, 1-10%, or 1-5 wt% based on the total weight of the polymer. In some embodiments, the dry adhesive polymer may be an acrylic polymer.

[0061] In embodiments where the adhesive comprises a dry adhesive polymer and a wet adhesive polymer, the benefits of using these types of polymers (e.g., adhesion to the electrode(s) and ease of manufacturing of a stacked or prismatic cell) can be realized. In some embodiments, the ceramic coating, electrode material, metal, metallic material, or solid electrolyte material may be directly applied to the coating containing the adhesive.

[0062] (3) Binder The binder is not so limited.

[0063] In some embodiments, the binder may be acrylic. In some embodiments, the binder may be a polymeric, oligomeric, or elastomeric binder comprising, consisting of, or essentially consisting of a polymeric, oligomeric, or elastomeric material, without limitation. Any polymeric, oligomeric, or elastomeric material that does not conflict with the present disclosure may be used. The binder may be ion-conductive, semi-conductive, or non-conductive. Any gel-forming polymer recommended for use in a lithium polymer battery or a solid electrolyte battery may be used. For example, the polymeric binder may include at least one, or two, or three, etc. selected from polyamide polymers, polyvinyl alcohol (PVA), polyacrylic acid (PAA), polyvinyl acetate (PVAc), carboxymethyl cellulose (CMC), isobutylene polymers, acrylic resins, latexes, aramids, or any combination of these materials.

[0064] In some preferred embodiments, the polymeric binder comprises, consists of, or consists essentially of a polylactam polymer that is a homopolymer, copolymer, block polymer, or block copolymer derived from a lactam. In some embodiments, the polymeric material comprises a homopolymer, copolymer, block polymer, or block copolymer according to formula (1).

[0065]

Chemical formula

[0066] Wherein, R1, R2, R3, and R4 may be alkyl or aromatic substituents, and R5 may be an alkyl substituent, an aryl substituent, or a substituent containing a condensed ring; preferred polylactams are homopolymers or copolymers in which the copolymerizable group X can be derived from vinyl, substituted or unsubstituted alkyl vinyl, vinyl alcohol, vinyl acetate, acrylic acid, alkyl acrylate, acrylonitrile, maleic anhydride, maleimide, styrene, polyvinylpyrrolidone (PVP), polyvinyl valerolactam, polyvinyl caprolactam (PVCap), polyamide, or polyimide; m may be an integer between 1 and 10, preferably between 2 and 4, and the ratio of l to n is such that 0 ≦ l:n ≦ 10 or 0 ≦ l:n ≦ 1. In some preferred embodiments, the homopolymer, copolymer, block polymer, or block copolymer derived from a lactam is at least 1, at least 2, or at least 3 selected from the group consisting of polyvinylpyrrolidone (PVP), polyvinyl caprolactam (PVCap), and polyvinyl-valerolactam.

[0067] In another preferred embodiment, the polymeric binder comprises, consists of, or consists essentially of polyvinyl alcohol (PVA). The use of PVA can result in a low curl coating layer, which helps keep the substrate to which the coating is applied stable and flat, for example, helping to prevent curling of the substrate. PVA may be added, in particular, in combination with any of the other polymeric, oligomeric, or elastomeric materials described herein when low curl is desired.

[0068] In another preferred embodiment, the polymeric binder may comprise, consist of, or consist essentially of an acrylic resin. The type of acrylic resin is not particularly limited, and may be any acrylic resin that can, for example, impart a new improved coating composition that can be used to make a battery separator with improved safety and that does not contravene the objectives described herein. For example, the acrylic resin may be at least one, or two, or three, or four selected from the group consisting of polyacrylic acid (PAA), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), and polymethyl acrylate (PMA).

[0069] In other preferred embodiments, the polymeric binder may comprise, consist of, or consist essentially of carboxymethyl cellulose (CMC), isobutylene polymer, latex, or any combination thereof. These may be added alone or together with any other suitable oligomeric, polymeric, or elastomeric material.

[0070] In some embodiments, the polymeric binder may include only water, an aqueous or water-based solvent, and / or a solvent that is a non-aqueous solvent. When the solvent is water, in some embodiments, no other solvent is present. An aqueous or water-based solvent may include more than half (more than 50%) water, more than 60% water, more than 70% water, more than 80% water, more than 90% water, more than 95% water, or more than 99%, but less than 100% water. An aqueous or water-based solvent may include, in addition to water, a polar or non-polar organic solvent. The non-aqueous solvent is not limited and may be any polar or non-polar organic solvent that is compatible with the objectives described herein. In some embodiments, the polymeric binder includes only a trace amount of solvent, and in other embodiments, it includes 50% or more of the solvent, sometimes 60% or more, sometimes 70% or more, sometimes 80% or more, etc.

[0071] In some preferred embodiments, the amount of the binder may be less than 20%, less than 15%, less than 10%, or less than 5% of the total solids in the coating. In some particularly preferred embodiments, the amount of the binder may be 10% or less, or 5% or less of the total solids in the coating.

[0072] Separator or porous membrane The battery separator (uncoated) or porous membrane described herein is not very limited, and any battery separator or porous membrane can be used. For example, the separator or porous membrane may be a single-layer, two-layer, three-layer, or multi-layer separator or porous membrane produced by any type of process including dry processes and wet processes known in the art.

[0073] In a preferred embodiment, the separator is porous, nanoporous, microporous, or macroporous. In some particularly preferred embodiments, the separator is microporous. For example, the separator may have an average pore size between 0.1 and 1.0 microns.

[0074] In some preferred embodiments, the separator or membrane does not have a shut-down function by itself. For example, the separator does not have a shut-down function at a temperature below 160 °C, below 150 °C, or below 140 °C. For example, in some embodiments, the separator is not the three-layer shut-down separator disclosed in U.S. Patent No. 5,952,120 to Celgard. However, in some embodiments, the separator itself may well have a shut-down function (e.g., at a temperature below 160 °C, below 150 °C, or below 140 °C), and the coating can be used to lower the shut-down start temperature or expand the shut-down window.

[0075] In some preferred embodiments, the separator is a single-layer separator.

[0076] In some preferred embodiments, the battery separator described herein is a dry-process battery separator or membrane.

[0077] The dry process is, in some embodiments, a process that does not use any pore-forming factor / pore-forming agent or beta-nucleating factor / beta-nucleating agent. In some embodiments, the dry process is one that does not use any solvent, wax, or oil. In some embodiments, the dry process is one that does not use any pore-forming factor / pore-forming agent or beta-nucleating factor / beta-nucleating agent and also does not use any solvent, wax, or oil. In such embodiments, the dry process may be a dry stretching process. An exemplary dry stretching process known as the Celgard dry stretching process is described in Chen et al., Structural Characterization of Celgard® Microporous Membrane Precursors: Melt-Extruded Polyethylene Films, J. of Applied Polymer Sci., vol. 53, 471-483 (1994), which is hereby incorporated by reference in its entirety. The Celgard dry stretching process refers to a process in which pore formation is obtained from stretching at least a non-porous, oriented precursor in the machine direction. Kesting, Robert E., Synthetic Polymeric Membranes, A Structural Perspective, Second Edition, John Wiley & Sons, New York, N.Y., (1985), pages 290-297 also discloses a dry stretching process, which is hereby incorporated by reference in its entirety. In the dry stretching process according to some preferred embodiments, the process may include a stretching step. The stretching step may include, consist of, or consist essentially of uniaxial stretching (e.g., stretching only in the MD direction or only in the TD direction), biaxial stretching (e.g., stretching in the MD and TD directions), or multiaxial stretching (e.g., stretching along three or more different axes, e.g., MD, TD, and another axis).In some embodiments, the dry stretching process may include, consist of, or consist essentially of the extrusion step and the stretching step, in this order or not in this order. In some embodiments, the dry stretching process may include, consist of, or consist essentially of the extrusion step, the annealing step, and the stretching step, in this order or not in this order. The extrusion step may be, in some embodiments, an inflation film extrusion step or a cast film extrusion process. In some embodiments, the non-porous precursor is extruded and stretched to form pores. In some embodiments, the non-porous precursor is extruded, annealed, and then stretched to form pores. In other embodiments, the porous or non-porous precursor may be formed by methods other than extrusion, such as by sintering or printing, and the stretching may be performed on the precursor to form pores or enlarge existing pores.

[0078] In some embodiments, a pore-forming factor / pore-forming agent, or a beta-nucleating factor / beta-nucleating agent may be used, and the process is still considered a dry process. For example, a particle stretching process can be considered a dry process because oil or solvent is not extruded with the polymer, not extracted from the extruded polymer, and forms pores. In a particle stretching process, particles, such as silica or calcium carbonate, are added to the polymer mixture, and these particles help to form pores. In such a method, for example, a polymer mixture containing particles and polymer is extruded to form a stretched precursor, and voids are created around the particles. In some embodiments, the particles can be removed after the voids are created. The particle stretching process may include a stretching step before and / or after the removal of the particles, but the particle stretching process is not considered a dry stretching process because the principle pore-forming mechanism is the use of non-stretching particles.

[0079] In some preferred embodiments, the structure of the dry-process porous membrane can have one or more prominent features. For example, the dry-process membrane may contain more than 10% by weight of polypropylene. Wet processes, or other processes using solvents, are generally not compatible with polypropylene because the solvent can degrade polypropylene. Therefore, wet-process porous membranes typically contain no more than 10% polypropylene, most typically 5% or less. Another prominent feature of some dry-process porous membranes, particularly those used as battery separators, is that they can have a shutdown function. The shutdown function can, in some cases, be imparted by a PP / PE / PP structure. This is unique to dry-process membranes because the layer mainly containing polypropylene (PP) generally cannot be formed in wet processes. The dry process is uniquely suitable for forming the PP / PE / PP shutdown membrane structure.

[0080] In some embodiments, the identification of the dry-process porous membrane can have the presence of lamellae and fibrils as shown in FIG. 3. For example, the porous membrane can have a structure such as that shown in FIG. 3 or FIGS. 4A and 4B. FIGS. 4A and 4B are FESM images showing slit-like micropores in a Celgard® microporous membrane containing PE (A) and PP (B). In some embodiments, the pores or micropores of the dry-process porous membrane can be circular, elliptical, semi-circular, trapezoidal, etc.

[0081] In some embodiments, a notable feature of the dry-process porous membrane is that it does not contain or substantially does not contain pinholes. Pinholes are considered defects and generally are not intentionally formed features of the dry-process porous membrane. In some embodiments, the microporous membrane of the dry process may not contain or substantially may not contain pinholes exceeding 10 nm. In some preferred embodiments, the pores of the dry-process porous membrane are tortuous. In some embodiments, a notable feature of the dry-process porous membrane is twist. In some embodiments, the twist of the dry-process porous membrane is greater than 1, greater than 1.2, greater than 1.3, greater than 1.4, greater than 1.5, greater than 1.6, greater than 1.7, greater than 1.8, greater than 1.9, or greater than 2.0. In some embodiments, the formula for roughly calculating the twist is formula (2), Twist = x / t (2) wherein, "x" is the length of the opening or pore in the porous membrane, and "t" is the thickness of the membrane. A pinhole has a twist of 1 because the length of the pinhole is the same as the thickness of the membrane. A tortuous pore has a twist greater than 1 as shown in FIG. 5 because the length of the pore is longer than the thickness of the membrane.

[0082] In some embodiments, the dry-stretched porous membrane is semi-crystalline. In some embodiments, the dry-stretched porous membrane is semi-crystalline and is oriented in a single direction. For example, the membrane may be MD-oriented. A porous film formed by a wet process, for example, a film formed by a beta-nucleation process, may be randomly oriented.

[0083] Composite or device The composite or device includes any of the coated battery separators or coated porous membranes described above herein, and one or more electrodes provided in indirect or direct contact therewith, such as an anode, a cathode, or an anode and a cathode. The type of electrode is not very limited. For example, the electrode may be suitable for use in a lithium-ion secondary battery.

[0084] In some embodiments, the composite or device is a cell selected from at least one of the following: a cylindrical cell, a pouch cell, a prismatic cell, a wound cell, a folded cell, a wrapping cell, a pocket cell, or a stacked cell. In some embodiments, the composite or device is a secondary battery, such as a lithium-ion battery. A lithium-ion battery according to some embodiments herein is shown in FIG. 6.

[0085] A suitable anode may have an energy capacity of 372 mAh / g or more, preferably ≥700 mAh / g, and most preferably ≥1000 mAh / g. The anode is composed of a lithium metal foil or a lithium alloy foil (e.g., a lithium aluminum alloy), or a mixture of lithium metal and / or lithium alloy and materials, such as carbon (e.g., coke, graphite), nickel, copper. The anode is not made only of an intercalation compound containing lithium or an insertion compound containing lithium.

[0086] A suitable 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 include, for example, MoS2, FeS2, MnO2, TiS2, NbSe3, LiCoO2, LiNiO2, LiMn2O4, V6O 13, V2O5, and CuCl2 are included. Suitable polymers include, for example, polyacetylene, polypyrrole, polyaniline, and polythiophene.

[0087] Any battery separator described above herein can be incorporated into any automobile that is fully or partially battery-powered, such as an electric vehicle, or a device, such as a mobile phone or a laptop computer.

[0088] Various embodiments of the present invention are described in connection with the achievement of various objects of the present invention. These embodiments should be recognized as merely illustrative of the principles of the present invention. Many variations and adaptations will be readily apparent to those skilled in the art without departing from the spirit and scope of the present invention.

[0089] In some aspects, a capacitor including at least one coated separator described herein is disclosed. In some embodiments, the capacitor may be a supercapacitor.

[0090] In some embodiments, a coated battery separator of a coated porous membrane described herein having a further layer directly on top of the coating is described. In such embodiments, the coating may comprise, consist of, or consist essentially of at least an adhesive. In some preferred embodiments, the coating may be an aqueous or water-based coating. Such a coating is ideal for directly applying another coating on top of it due to its excellent uniformity. For example, the adhesiveness of the coating can be uniform. The layer provided directly on top may be at least one of a ceramic coating, a coating or layer of an electrode material, a coating or layer of a solid electrolyte material, a metallic layer or coating, a metal-containing coating or layer, a metal layer or coating, etc.

Examples

[0091] Example 1: In Example 1, a single-layer separator (porous membrane) made of polypropylene was coated with a coating slurry or mixture containing PVDF as an adhesive and PE beads as a shutdown agent. In this embodiment, a binder was used in Example 1a and not used in Example 1b. In Example 1b, PVDF and PE were dispersed in a water-based solvent that may contain water or up to 50% alcohol or other water-soluble solvents. The coating in 1a was also an aqueous, water-based, or water-based coating. The coating was applied to one or both sides (it may be one side) of the separator (porous membrane). A schematic image of the separator with both sides coated according to Example 1 is shown in FIG. 7. The separator (porous membrane in Example 1) did not have a shutdown function by itself.

[0092] Example 2 In Example 2, a single-layer separator made of polypropylene was coated with a slurry or mixture containing a coating comprising PVDF as a wet adhesive, a dry adhesive, and PE beads as a shutdown agent. A binder was used in Example 2a and not used in Example 2b. In Example 2b, PVDF as a wet adhesive, a dry adhesive, and PE beads as a shutdown agent were dispersed in a water-based solvent having up to 50% alcohol or another water-soluble solvent. The coating in 2a was also a water-based or aqueous coating. The coating was applied to one or both sides of the separator. A schematic image of the separator with both sides coated according to Example 2 is shown in FIG. 8. The separator in Example 1 did not have a shutdown function by itself.

[0093] Examples 3 to 202 contain the amounts of adhesive and shutdown agent shown in the following table. In each example where "X" is in the "Binder" column, the binder is added with a solvent which may be water or a water-based or organic solvent. The binder is added in an amount not exceeding 10% of the total solids in the coating. In some embodiments, no binder is added, and for example, the adhesive, shutdown agent, and / or inorganic or heat-resistant particles can be dispersed in an organic solvent or water or a water-based solvent without using a binder. The water-based solvent may contain up to 50% of another solvent soluble in alcohol or water. Inorganic or heat-resistant particles are added in each example where "X" is in the "Inorganic or Heat-Resistant Particles" column. A dash ("-") means that the component is not present in the coating of that example. Examples 3 to 202 are separators with the same coating on each side of a porous membrane (separator), for example, a polypropylene monolayer membrane (separator), i.e., separators coated on both of the two sides. Two-sided coated separators were also prepared where one coating is a ceramic coating and the other coating has a composition like that in Examples 3 to 238. Exemplary one-sided coated separators were also prepared where one coating was applied and the composition of the coating corresponded to the coating composition used in Examples 3 to 238. Additionally, embodiments like those in Examples 3 to 238 were prepared where the inorganic or organic heat-resistant particles are nanoparticles (particle sizes less than about 500 nm, less than 450 nm, less than 400 nm, less than about 350 nm, less than about 300 nm, 250 nm or less than 200 nm) and non-nanoparticles (particle sizes greater than 250 nm, greater than 300 nm, greater than 350 nm, greater than 400 nm, greater than 450 nm, or greater than 500 nm and up to 1,000 nm). Finally, examples like those in Examples 3 to 238 were formed where the coating was formed on top of a ceramic or nanoceramic layer. The coating can be formed continuously or discontinuously on the ceramic or nanoceramic layer.The ceramic or nanoceramic layer described in this specification is a layer containing 80%, 85% or more, 90% or more, 95% or more, or 98% or more ceramic or nanoceramic by weight, and optionally a binder or other additives. All of the embodiments described herein were carried out using water as the solvent, and then a water-based or aqueous coating solution was formed for coating. The embodiments were also carried out using a solvent-based coating solution. Aqueous means that the solvent is only water or water and alcohol or other non-organic water-soluble solvents. For example, an aqueous or water-based coating may contain a solvent that is water and up to 50% alcohol or non-organic water-soluble solvents, such as PVA.

[0094]

Table 1-1

[0095]

Table 1-2

[0096]

Table 1-3

[0097]

Table 1-4

[0098]

Table 1-5

[0099]

Table 1-6

[0100]

Table 1-7

[0101]

Table 1-8

[0102]

Table 1-9

[0103]

Table 1-10

[0104]

Table 1-11

[0105] The use of nanoceramics or nano-inorganic materials (nanoalumina in the examples) has been found to yield excellent results. For example, the use of nanoalumina in an adhesive or adhesive coating resulted in a reduction of self-adhesion by about 50% as shown in Figure 12. In Figure 12, the nanoalumina used had a particle size of 250 nm. Without wishing to be bound by any particular theory, a proposed mechanism explaining why self-adhesion is reduced is shown in Figure 13. Nanoceramics or nano-inorganic materials (nanoalumina in the examples) have also been found to improve the function of the shutdown coating. For example, the resistance increased by more than 100 ohms, more than 500 ohms, more than 1,000 ohms, more than 2,000 ohms, more than 3,000 ohms, more than 4,000 ohms, more than 5,000 ohms, more than 6,000 ohms, more than 7,000 ohms, more than 8,000 ohms, more than 9,000 ohms, or more than 10,000 ohms during shutdown. These increases in resistance occurred at temperatures below 135 °C, below 130 °C, below 125 °C, below 120 °C, below 115 °C, below 110 °C, below 105 °C, below 100 °C, or below 95 °C. This can be seen in Figure 14 comparing embodiments containing conventional ceramics with a size of 700 nm and embodiments containing nanoceramics with a size of 250 nm. Without wishing to be bound by any particular theory, this improved-function shutdown coating is said to be partly due to the fact that the polymer can flow and block the pores of the separator. Larger-sized inorganic or ceramic or heat-resistant particles can make it more difficult for the polymer to flow and / or block the pores of the separator.

[0106] Figure 15 shows images of coatings containing PVDF and nanoceramics, and PVDF and ceramics, respectively. The nanoceramics-containing coating can be made thinner, at least partly due to the presence of the nanoceramics.

[0107] In some embodiments, aspects or purposes, a coated separator including a coating on one or both sides of a separator membrane is disclosed. The coating may contain at least one of an adhesive, a shutdown agent, and a binder. The coating containing these components does not contain any inorganic or organic heat-resistant materials including ceramic materials, or contains a small amount of inorganic or organic heat-resistant materials including ceramic materials. The separator may be a separator that does not have a shutdown function by itself. For example, the separator membrane of the separator may be a single-layer separator membrane made of polypropylene. A battery cell, a secondary battery, and a capacitor containing at least one of the coated separators disclosed herein are also disclosed.

[0108] In some embodiments, aspects or purposes, a coated separator membrane including a coating on one or both sides of a separator membrane is disclosed. The coating may contain at least one of an adhesive, a shutdown agent, and a binder. The coating containing these components does not contain any inorganic or organic heat-resistant materials including ceramic materials, or contains a small amount of inorganic or organic heat-resistant materials including ceramic materials. The separator may be a separator that does not have a shutdown function by itself. For example, the separator membrane of the separator may be a single-layer separator membrane made of polypropylene. Also, a battery cell, a secondary battery, and a capacitor containing at least one of the coated separators disclosed herein are also disclosed.

[0109] In some embodiments, aspects or purposes, a coated membrane including a coating on one or both sides of a polymer membrane is disclosed. The coating may contain at least one of an adhesive, a shutdown agent, and a binder. The coating containing these components may not contain any inorganic or organic heat-resistant materials including ceramic materials, or may contain a small amount of inorganic or organic heat-resistant materials including ceramic materials. The membrane, or the base film, may be a membrane that does not have a shutdown function by itself. For example, the membrane of the coated membrane may be a single-layer or multi-layer membrane made of polyolefin, polypropylene, blend, etc. Also disclosed are batteries, cells, secondary batteries, capacitors, textiles, filters, garments, etc. containing at least one of the coated membranes disclosed herein.

[0110] In some embodiments, aspects or purposes, a multi-layer or composite membrane including a coating, layer, or treatment on one or both sides of a polymer membrane is disclosed. The coating, layer, or treatment may contain at least one of an adhesive, a shutdown agent, and a binder. The coating, layer, or treatment containing these components may not contain any inorganic or organic heat-resistant materials including ceramic materials, or may contain a small amount of inorganic or organic heat-resistant materials including ceramic materials. The membrane or the base film may be a membrane that does not have a shutdown function by itself. For example, the base film of the multi-layer membrane may be a single-layer or multi-layer membrane made of polyolefin, polypropylene, blend, etc. Also disclosed are batteries, cells, secondary batteries, capacitors, textiles, filters, garments, etc. containing at least one of the multi-layer or composite membranes disclosed herein.

[0111] Various embodiments of the present invention are described in connection with the achievement of various objects of the present invention. These embodiments should be recognized as merely illustrative of the principles of the present invention. Many variations and adaptations of the present invention will be readily apparent to those skilled in the art without departing from the spirit and scope of the present invention. For example, non-woven fabrics such as fibers, meshes, nets, etc. may be added to one or both sides of a coated separator, a coated membrane, a multilayer or composite membrane, etc.

Claims

1. A coated separator or a coated porous membrane, comprising: a separator; and at least one coating comprising an adhesive, a shutdown agent, and a binder, wherein the coating contains nano heat-resistant particles of 1.0% or more and less than 10% of the total solid content of the coating, wherein the adhesive comprises a wet adhesive containing PVDF (polyvinylidene fluoride), wherein the shutdown agent comprises PE (polyethylene) beads, wherein the nano heat-resistant particles are selected from the group consisting of polyimide resin, melamine resin, phenol resin, polymethyl methacrylate (PMMA) resin, polystyrene resin, polydivinylbenzene (PDVB) resin, carbon black, graphite, and combinations thereof, the coated separator or the coated porous membrane.

2. The coated separator or the coated porous membrane according to claim 1, wherein the separator is a separator coated on one side or both sides.

3. The coated separator or the coated porous membrane according to claim 2, wherein the separator is coated on both sides, and the coatings on the two sides are the same, different, or different, and one of the coatings on the two sides is a ceramic coating.

4. The coated separator or the coated porous membrane according to claim 1 or 2, wherein the separator has no shutdown ability at a temperature of 150 °C or less than 140 °C without the coating, and the separator without the shutdown ability at a temperature of 150 °C or less than 140 °C without the coating is a dry process separator.

5. the separator is made of polypropylene, the separator is a single-layer separator made of polypropylene, or the separator is a dry process single-layer separator made of polypropylene, the coated separator or the coated porous membrane according to claim 1.

6. The coated separator or the coated porous membrane according to claim 1, 2 or 5, wherein the coating is an aqueous coating.

7. A composite comprising the coated separator or coated porous membrane according to any one of claims 1, 2 or 5, wherein a further coating is provided directly on the upper surface of at least one of said coatings, said composite.

8. The composite according to claim 7, wherein the further coating is an aqueous coating.

9. The composite according to claim 7, wherein the further coating is a ceramic coating, a polymer coating, a coating of an electrode material, a coating of a solid electrolyte material, a metal-containing coating, or a metal coating.

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