Coated separator and related methods

Abstract

Disclosed is an improved non-continuous and water-based adhesive coating containing large polymeric particles or agglomerate with an average particle size (D50) greater than 5 microns. The coating may be applied onto one or both sides of a porous film or membrane. A method of forming the coating involves applying an aqueous slurry containing the large polymeric particles with a D50 greater than 5 microns onto a porous membrane. The method of application may be a spray coating method. The coated porous film or membrane may be a battery separator. The coated porous film or membrane may include a fiber layer on at least one side. The fiber layer can be adhered to a porous film or membrane (such as a wet PE, dry PR, dry PP / PE / PP trilayer, etc.) by coating layers with pressure activated at different temperature from 25 deg C to 110 deg C or may be extruded, electrospun, laminated, co-extruded, or the like to or on the porous film or membrane or to, in, or on the coating.

Description

COATED SEPARATOR AND RELATED METHODSFIELD

[0001] This application relates to coated porous membranes, particularly coated porous or microporous battery separators. This application also relates to coating methods that may be used to form the coated porous membranes and / or the coated porous or microporous battery separators disclosed herein.BACKGROUND

[0002] Water-based adhesive coatings have been described. See, for example, US 2016 / 0164060 and US 10,559,802, each assigned to Celgard, LLC. In these documents organic particles, e.g., Polyvinylidene fluoride or PVDF particles have an average particle size less than 5 microns, preferably less than 2 microns, and in some cases less than 1 micron. Certain smaller-particle coatings may have an increased Gurley, and consequently may have increased electrical resistance (ER). Higher Gurley and ER products may not be preferred for some applications.

[0003] In the past, larger PVDF particles could only be used in solvent-based, e.g., acetone- based, coatings where PVDF powder, not PVDF-latex is added. Solventbased coatings may not be preferred due to their negative environmental impacts. Also, with solvent based coating, solvent can get stuck in the pores, decreasing porosity, and increasing Gurley and electrical resistance (ER). Also, when solvent-based coatings are used on top of a ceramic coating layer, the solvent allows the PVDF to penetrate the ceramic coating and the porous membrane. This is counterproductive because it is desirable to keep PVDF on the surface where it can provide adhesive properties.Additionally, in a solvent based coating, the PVDF particles are dissolved by the solvent and cannot be seen in a resulting coating. This is because most PVDF dissolves in the solvent, but not in water. In a water-based coating, PVDF particles are visible in the resulting coating.

[0004] It is desirable to avoid the negative effects of using solvent-based coating, higher Gurley, and / or higher ER.SUMMARY

[0005] Coatings described herein are preferably water-based coatings that include large particles or agglomerate, e.g., particles or agglomerate with an average particle size (D50) greater than 5 microns. These coatings have at least the following advantages: (1 ) environmentally friendly due to the fact that harmful solvents are not used, (2) avoid the inefficiencies associated with powder-based coatings, (3) decreased Gurley increase, resulting in lower ER of the resulting coated product, (4) large particles can absorb a lot of electrolyte, which can extend battery cycle life, and (5) large particles can penetrate electrodes’ porous structure and provide good adhesion where smaller particles cannot do so without causing possibly significant Gurley increase.

[0006] In one aspect, a coated composite is described. The composite comprises, consists of, or consists essentially of (1 ) a porous membrane, and (2) a coating on at least one side of the porous membrane. The coating comprises, consists of, or consists essentially of particles or agglomerate formed from at least one of a low melting point (Tm) polymer having a Tmin a range from about 20°C (or 20 deg C) to about 170°C, a low glass transition temperature (Tg) polymer having a Tgfrom about -35°C to 60°C, or combinations thereof. The particles or agglomerate have an average particle size (D50) of from 3 microns to 20 microns, from 5 microns to 20 microns, from 5 to 15 microns, or from 5 to 10 microns. In some embodiments, the coating is a water-based coating. In some embodiments, the coating is a non-continuous coating.

[0007] In some embodiments, the coating comprises particles or agglomerate formed from a low Tgpolymer having a Tgfrom about -40°C to 60°C or from about -40°C to - 30°C. In some embodiments, the particles or agglomerate are formed from a PVDF, a PVDF-HFP, or combinations thereof.

[0008] The porous membrane of the composite may be a microporous membrane, such as a polyolefin membrane, possibly preferably a dry process polypropylene or polyethylene membrane in some embodiments. In selected embodiments, the composite or the microporous membrane is a battery separator.

[0009] In another aspect, another coated composite is described. The composite comprises, consists of, or consists essentially of (1 ) a porous membrane, and (2) a coating on at least one side of the porous membrane. The coating comprises, consistsof, or consists essentially of acrylate particles or agglomerate with a high electrolyte swelling ratio above 200% weight ratio change or up to above 950% weight ratio change. The particles or agglomerate have an average particle size (D50) of from 3 microns to about 20 microns, from 5 microns to 20 microns, from 5 to 15 microns, or from 5 to 10 microns. In some embodiments, the coating is a water-based coating. In some embodiments, the coating is a non-continuous coating.

[0010] In another aspect, a method for forming a coating is disclosed. The method comprises, consists of, or consists essentially of a step of applying a water-based slurry onto at least one surface of a porous membrane to form the coating. The slurry, in some embodiments, comprises polymeric particles or agglomerate having an average particle size (D50) of from 3 microns to 20 microns, from 5 microns to 20 microns, 5 microns to 15 microns, or 5 microns to 10 microns. The coating formed, in some embodiments, is a non-continuous coating. In some embodiments, a spray-coating method is used to apply the coating. The spray coating method may be an air spray coating method, an airless spray method, or an air-assisted spray method.

[0011] In some embodiments, the polymeric particles or agglomerate in the slurry are formed from at least one of a low melting point (Tm) polymer having a Tm in a range from about 20°C to about 170°C, a low glass transition temperature (Tg) polymer having a Tgfrom about -35°C to 60°C, or combinations thereof. In some embodiments, the particles or agglomerate are acrylate particles with a high electrolyte swelling ratio above 200% weight ratio change or up to above 950% weight ratio change.DESCRIPTION OF THE DRAWINGS

[0012] Fig. 1 is as scanning electron microscope image showing a top-down view of a composite with a non-continuous water-based coating having large polymeric particles as described herein.

[0013] Fig. 2 is as scanning electron microscope image showing a cross-sectional view of a composite with a non-continuous water-based coating having large polymeric particles as described herein.

[0014] Fig. 3 is as scanning electron microscope image showing a cross-sectional view of a composite with a non-continuous water-based coating having large polymeric particles as described herein.

[0015] Fig. 4 is as scanning electron microscope image showing a cross-sectional view of a comparative (prior art) coated membrane where the coating is continuous and comprises small polymeric particles.

[0016] Fig. 5 is as scanning electron microscope image showing a cross-sectional view of a comparative (prior art) coated membrane where the coating is continuous and comprises small polymeric particles.

[0017] Fig. 6 is an illustration of a composite in accordance with an aspect of the invention.

[0018] Fig. 7 is an illustration of a composite in accordance with an aspect of the invention.

[0019] Fig. 8 is an illustration of a composite in accordance with an aspect of the invention.

[0020] Fig. 9 is an illustration of a composite in accordance with an aspect of the invention.

[0021] Fig. 10 is a schematic illustration of a side view composite with an extruded fiber layer in accordance with an aspect of the invention.

[0022] Fig. 11 is a SEM surface view image an island or discontinuous adhesive layer in accordance with an aspect of the invention.

[0023] Fig. 12 is a photographic image of a composite in accordance with an aspect of the invention.DETAILED DESCRIPTION

[0024] Embodiments described herein can be understood more readily by reference to the following detailed description, examples, and figures. Elements, apparatus, and methods described herein, however, are not limited to the specific embodiments presented in the detailed description, examples, and figures. It should be recognized that the exemplary embodiments herein are merely illustrative of the principles of the invention. Numerous modifications and adaptations will be readily apparent to those of skill in the art without departing from the spirit and scope of the invention.

[0025] In addition, all ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein. For example, a stated range of “1.0 to 10.0” should be considered to include any and all subranges beginning with a minimum valueof 1.0 or more and ending with a maximum value of 10.0 or less, e.g., 1.0 to 5.3, or 4.7 to 10.0, or 3.6 to 7.9.

[0026] All ranges disclosed herein are also to be considered to include the end points of the range, unless expressly stated otherwise. For example, a range of “between 5 and 10” or “5 to 10” or “5-10” should generally be considered to include the end points 5 and 10. Further, when the phrase “up to” is used in connection with an amount or quantity; it is to be understood that the amount is at least a detectable amount or quantity. For example, a material present in an amount “up to” a specified amount can be present from a detectable amount and up to and including the specified amount. Additionally, in any disclosed embodiment, the terms “substantially,” “approximately,” and “about” may be substituted with “within [a percentage] of” what is specified, where the percentage includes 0.1 , 1 , 5, and 10 percent.

[0027] The subject matter of aspects of the present disclosure is described with specificity herein to meet statutory requirements. However, the description itself is not intended to limit the scope of this patent. Rather, the inventor(s) have contemplated that the claimed subject matter might also be embodied in other ways, to include different steps or combinations of steps similar to the ones described in this document, in conjunction with other present or future technologies. Moreover, although the terms “step” and / or “block” can be used herein to connote different elements of methods employed, the terms should not be interpreted as implying any particular order among or between various steps disclosed herein unless and except when the order of individual steps is explicitly described

[0028] Disjunctive language such as the phrase “at least one of X, Y, or Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to present that an item, term, etc., may be either X, Y, or Z, or any combination thereof (e.g., X, Y, and / or Z). Thus, such disjunctive language is not generally intended to, and should not, imply that certain embodiments require at least one of X, at least one of Y, or at least one of Z to each be present.Coated Composites

[0029] In one aspect, object or embodiment, described herein are coated composites comprising the following: (1 ) a porous membrane, and (2) a coating provided on one or both sides of the porous membrane. Further detail is provided herein below.(1 ) Porous Membrane

[0030] The porous membrane of the composite is not so limited, and may be a nanoporous, microporous, mesoporous, or macroporous membrane. In some preferred embodiments, the porous membrane may be a microporous membrane having an average pore size less than 1 micron, less than 0.9 micron, less than 0.8 micron, less than 0.7 micron, less than 0.6 micron, less than 0.5 micron, less than 0.4 micron, less than 0.3 micron, less than 0.2 micron, less than 0.3 micron, less than 0.2 micron, less than 0.1 micron, less than 0.05 micron, less than 0.04 micron, less than 0.03 micron, less than 0.02 micron, or less than 0.01 micron.

[0031] In some preferred embodiments, the porous membrane may be a battery separator. It is understood by those skilled in the art, that not every porous membrane is capable of being a separator. Some minimum requirements for being a separator are that the porous membrane must be ionically conductive, e.g., lithium ions must be able to flow across it, and the membrane must also be electrically insulative. It is understood by those skilled in the art that porous membranes with through-holes are not preferred for use as battery separators. Through-holes are considered to be a defect in a battery separator. Instead, porous membranes used as battery separators include tortuous pores.

[0032] The composition of the porous membrane is not so limited. In some preferred embodiments, the composition of the porous membrane comprises, consists of, or consists essentially of a thermoplastic polymer, e.g., a polyolefin such as polyethylene, polypropylene, or combinations thereof. In some embodiments, the porous membrane may be formed using a dry process such as the Celgard dry process, which involves the extrusion of the thermoplastic polymer without the use of plasticizers, oils, solvent, poreformers, etc. In other embodiments, a wet-process may be used. A wet-process usesplasticizers, oils, solvents, pore-formers, or the like. It is known and understood that wet-process and dry-process membranes have different structures.

[0033] The thickness of the porous membrane is not so limited and may be from 1 to 30 microns, preferably from 1 to 20 microns, more preferably from 1 to 15 microns, and most preferably from 1 to 10 microns.(2) Coating

[0034] The coating layer may have a thickness from about 1 micron to about 10 microns, from about 2 microns to about 10 microns, from about 3 microns to about 10 microns, from about 4 microns to about 10 microns, from about 5 microns to about 10 microns, from about 6 microns to about 10 microns, from about 7 microns to about 10 microns, from about 8 microns to about 10 microns, or from about 9 microns to about 10 microns.

[0035] In preferred embodiments, the coating is a non-continuous coating. For example, the coating may include separated islands. These islands may have a size of >0 mm to about 3 mm.

[0036] In preferred embodiments, the loading of the coating may range from about 0.05 to 1 g / m2, from about 0.1 to 1 g / m2, from about 0.2 to 1 g / m2, from about 0.3 to 1 g / m2, from about 0.4 to 1 g / m2, from about 0.5 to 1 g / m2, from about 0.6 to 1 g / m2, from about 0.7 to 1 g / m2, from about 0.8 to 1 g / m2, or from about 0.9 to 1 g / m2.

[0037] In some embodiments, the coating is applied directly to a surface of the porous membrane. However, in other embodiments, intervening coating layers may exist between the coating and the porous membrane. In some embodiments, the intervening coating layer or layers may include a ceramic coating.

[0038] In preferred embodiments, the coating is a water-based coating. As understood by those skilled in the art, a water-based coating is a coating that is formed from a slurry using a solvent that is mainly water, i.e. , a water-based slurry. The term “mainly water” means that the solvent is 90% or more, 95% or more, 98% or more, 99% or more, or 100% water. A solvent other than water may be added in amounts not exceeding 10%, preferably not exceeding 5%, and most preferably not exceeding 2% or 1 % to improve the solubility of components of the slurry in the solvent. Other solvents may also be added in amounts not exceeding 10%, preferably not exceeding 5%, and mostpreferably not exceeding 2% or 1 % to improve the ability to dry applied slurry and form a coating. It is understood that water-based coatings may look different than solventbased slurries including the same components, but a different solvent, e.g., acetone instead of water. This may be because the components dissolve in the solvent, but not in water, or vice versa. In coatings where the components, e.g., the polymeric particles described herein, are not soluble in the solvent, one can see distinct particles in the coating. When the components e.g., the polymeric particles described herein, are soluble in the solvent, one may not see distinct particles in the final coating. Another distinction between water-based and solvent-based coatings is that water-based coatings typically will not have any residual solvent, e.g., acetone, remaining in the coating after the slurry is applied and dried.

[0039] In some embodiments, the coating results in a Gurley increase of from 1 s to 500s, 1 s to 450s, 1 s to 400s, 1 s to 250s, 1 s to 300s, 1 s to 250s, 1 s to 200 s, 1 s to 150s, 1s to 100s, or 1 s to 50s. This is determined by measuring the Gurley of the uncoated porous membrane, measuring the Gurley of the porous membrane with the coating on one-side, and subtracting the Gurley of the uncoated porous membrane from the Gurley of the porous membrane with the coating on one side. A small Gurley increase from the application of the coating is desirable. Less Gurley increase typically equates to a more favorable, i.e. , lower, electrical resistance. In embodiments where the coated composite is a coated battery separator, such separators may be used in fastcharge-discharge applications, e.g., 3C, EV, power tools etc. In such applications, lower ER separators, resulting in a reduction in battery internal resistance, are preferred. Without wishing to be bound by any particular theory, it is believed that the reduced Gurley increase is due to the use of larger polymeric particles as well as the application of a non-continuous coating.

[0040] In some preferred embodiments, the coating may exhibit a dry lamination adhesion between the separator and the electrodes ranging from greater than 0 N / m to as high as 50 N / m. In preferred embodiments, dry lamination adhesion between the separator and the electrodes is at or above 1 N / m. Too high adhesion may result in selfadhesion between coated porous films. The term “dry adhesion” as used herein ismeant to mean the adhesion between the separator and the electrodes before addition of electrolyte.

[0041] In preferred embodiments, the coating includes large polymeric particles or agglomerates having an average particle size (D50) that is from 3 microns to 20 microns, from 5 microns to 20 microns, 6 microns to 20 microns, 7 microns to 20 microns, 8 microns to 20 microns, 9 microns to 20 microns, 10 microns to 20 microns, 11 microns to 20 microns, 12 microns to 20 microns, 13 microns to 20 microns, 14 microns to 20 microns, 15 microns to 20 microns, 16 microns to 20 microns, 17 microns to 20 microns, 18 microns to 20 microns, or from 19 microns to 20 microns. In preferred embodiments, the particles or agglomerates have a D50 greater than 5 microns, which was not previously used in water-based coatings. Water-based latexes, e.g., PVDF latexes, available from vendors and used in prior water-based coatings included much smaller particles (i.e. , particles with a D50 in a range from 100 nm to 600 nm). Latexes with larger particles would settle down during shipping, making them difficult to use.

[0042] In some preferred embodiments, the polymeric particles or agglomerates are agglomerates made up of smaller particles. This can be seen in Fig. 2 and Fig. 3 herein. This structure may result in an ability of the polymeric particles to absorb electrolyte compared to similar polymeric particles that are not agglomerates. The space between the smaller particles in the agglomerate may hold electrolyte. Additionally, there is a surface area increase associated with the agglomerated structure.

[0043] In preferred embodiments, the large polymeric particles or agglomerates may be made from at least one of a low melting point (Tm) polymer having a Tmin a range from about 20°C to about 170°C, a low glass transition temperature (Tg) polymer having a Tg from about -35°C to 60°C, or combinations thereof. In some particularly preferred embodiments, a low Tm may be from about 20°C to about 170°C, from about 30°C to about 170°C, from about 40°C to about 170°C, from about 50°C to about 170°C, from about 60°C to about 170°C, from about 70°C to about 170°C, from about 80°C to about 170°C, from about 90°C to about 170°C, from about 100°C to about 110°C, from about 120°C to about 170°C, from about 130°C to about 170°C, from about 140°C to about 170°C, from about 150°C to about 170°C, or from about 160°C to about 170°C. In someembodiments, a low Tgmay be from about -35°C to 60°C, from about -30°C to 60°C, from about -25°C to 60°C, from about -20°C to 60°C, from about -15°C to 60°C, from about -10°C to 60°C, from about -5°C to 60°C, from about 0°C to 60°C, from about 5°C to 60°C, from about 10°C to 60°C, from about 15°C to 60°C, from about 20°C to 60°C, from about 25°C to 60°C, from about 30°C to 60°C, from about 35°C to 60°C, from about 40°C to 60°C, from about 45°C to 60°C, from about 50°C to 60°C, or from about 55°C to 60°C. Examples of low Tgor low Tm polymers are the following: a polyethylene oxide (PEO), a Polyvinylidene fluoride or PVDF, a Poly(vinylidene fluoride-co- hexafluoropropylene) or PVDF-HFP, and Epoxy, a PTFE, an acrylic based polymer (e.g., PMMA), a polyacrylonitrile (PAN), a polyurethane, a silicone, or the like.

[0044] In other preferred embodiments, the large polymeric particles or agglomerates may be acrylate particles acrylate particles with a high electrolyte swelling ratio above 200% weight ratio change, above 210% weight ratio change, above 220% weight ratio change, above 230% weight ratio change, above 240% weight ratio change, above 250% weight ratio change, above 260% weight ratio change, above 270% weight ratio change, above 280% weight ratio change, above 290% weight ratio change, above 300% weight ratio change, above 350% weight ratio change, above 400% weight ratio change, above 450% weight ratio change, above 500% weight ratio change, above 550% weight ratio change, above 600% weight ratio change, above 650% weight ratio change, above 700% weight ratio change, above 750% weight ratio change, above 800% weight ratio change, above 850% weight ratio change, above 900% weight ratio change, or above 950% weight ratio change. This is measured using LiPFe-EC-EMC electrolyte 30-70 vol.%. Particles are immersed in the electrolyte for 15 hours. Weight is measured before and after immersion for 15 hours

[0045] In addition to the large polymeric particles or agglomerates, the coating may comprise, consist of, or consist essentially of additional components including thickeners, binders, surfactants, dispersants, or combinations thereof. In some embodiments, the addition of thickeners may help prevent sedimentation of the large polymer particles.Method

[0046] Disclosed herein is a method of forming a coating. For example, in some embodiments, a method for forming a coating as described herein above with relation to the coated composites is described. The method may comprise, consist of, or consist essentially of applying a water-based slurry onto at least one surface of a porous membrane to form the coating. The water-based slurry, in preferred embodiments, comprises large polymeric particles or agglomerates having an average particle size (D50) in the range from 3 microns to 20 microns, from 5 microns to 20 microns, from 6 microns to 20 microns, from 7 microns to 20 microns, from 8 microns to 20 microns, from 9 microns to 20 microns, from 10 microns to 20 microns, from 11 microns to 20 microns, from 12 microns to 20 microns, from 5 microns to 20 microns, from 14 microns to 20 microns, from 15 microns to 20 microns, from 16 microns to 20 microns, from 17 microns to 20 microns, from 18 microns to 20 microns, or from 19 microns to 20 microns. In preferred embodiments, the D50 of the polymeric particles is greater than 5 microns. The large polymeric particles or agglomerates of the slurry are as described hereinabove with respect to the coating. The water-based slurry is as described herein above with respect to the coating. The water-based slurry may include components in addition to the large polymeric particles or agglomerates and the solvent that is mainly water. For example, the slurry may further comprise, consist of, or consist essentially of additional components including thickeners, binders, surfactants, dispersants, or combinations thereof.

[0047] The method by which the coating is applied is not so limited. In some embodiments, the coating may be applied by a manual or automatic spray coating method. In other embodiments, an air spray coating method may be used. In some embodiments, it is also possible to use an airless spray method, an air-assisted spray method, or a dry process by which particles are charged at the nozzle. The charged particles can then adhere to the porous membrane due to a static force between the particles and the porous membrane.

[0048] In some embodiments, the coating formed by the method is a non-continuous coating as described hereinabove.

[0049] In some embodiments, a further step of drying the applied slurry is performed.Examples

[0050] Example 1 : In this Example, a 16 micron trilayer (PP-PE-PP) or (PP / PE / PP) is coated on one side with a non-continuous water-based PVDF-HFP coating having a thickness of 1 micron to 10 microns. The thickness of the coating varies due to the application method and test method. The PVDF-HFP particles in the coating have a D50 of 3-7 microns. SEMs of Example 1 are shown in Figs. 1 , 2, and 3.

[0051] Example 2: This Example is like Example 1 , except that the loading of the coating is higher. See Table 2.

[0052] Comparative Example 1 : In this Example, a 16 micron trilayer (PP-PE-PP) is coated on one side with a non-continuous water-based PVDF-HFP coating having a thickness of about 1 to 5 microns. The PVDF-HFP particles in this Example are small. They have a D50 of 200 nm.

[0053] Comparative Example 1 : This Example is like Comparative Example 1 except that the coating is continuous and has a thickness of 0.3 to 1 micron. The PVDF-HFP particles in this Example are small. They have a D50 of 200 nm.Table 1 - Thickness Change Before and After Lamination

[0054] This shows that after the lamination of the separator the thickness dramatically decreases from 0- 10 microns to 0-2 microns. This result indicates penetration of the coating into the electrode, accounting for the reduced thickness of the laminate and the reduced thickness of the separator, and the relatively unchanged thickness of the electrode, after peeling.Table 2- Adhesion Level-

[0055] Disclosed is an improved non-continuous and water-based adhesive coating containing large polymeric particles or agglomerate with an average particle size (D50) greater than 5 microns. The coating may be applied onto one or both sides of a porous film. A method of forming the coating involves applying an aqueous slurry containing the large polymeric particles with a D50 greater than 5 microns onto a porous membrane. The method of application may be a spray coating method.

[0056] In accordance with selected aspects, objects or embodiments, the improved non-continuous and water-based adhesive coating may be an ambient or room temperature spray adhesive coating, a room temperature adhesion PVDF coating, or a non-continuous, water-based, spray coated ambient or room temperature adhesion PVDF or PVDF-HFP large particle coating or coated composite with a microporousmembrane substrate or base film, and the coating may be on one or both sides and may be over a ceramic coating on one or both sides of the substrate or base film, and the base film or substrate may be a polymer or polyolefin microporous membrane, a polyolefin monolayer microporous membrane, a multilayer polyolefin microporous membrane, a laminated polyolefin microporous membrane, a co-extruded polyolefin microporous membrane, or a combination thereof.

[0057] This application relates to coated porous membranes, particularly coated porous and / or microporous battery separators, to coating methods that may be used to form the coated porous membranes and / or the coated porous or microporous battery separators disclosed herein and / or claimed below.

[0058] Referring to the figures, Fig. 1 is as scanning electron microscope image showing a top-down view of a composite with a non-continuous water-based coating having large polymeric particles as described herein.

[0059] Fig. 2 is as scanning electron microscope image showing a cross-sectional view of a composite with a non-continuous water-based coating having large polymeric particles as described herein.

[0060] Fig. 3 is as scanning electron microscope image showing a cross-sectional view of a composite with a non-continuous water-based coating having large polymeric particles as described herein.

[0061] Fig. 4 is as scanning electron microscope image showing a cross-sectional view of a comparative (prior art) coated membrane where the coating is continuous and comprises small polymeric particles.

[0062] Fig. 5 is as scanning electron microscope image showing a cross-sectional view of a comparative (prior art) coated membrane where the coating is continuous and comprises small polymeric particles.

[0063] In another aspect of the invention, a composite comprises, consists essentially of, or consists of: a base film or membrane, a fiber layer, an optional ceramic layer, and a coating comprising large particles or agglomerates containing PVDF, preferably having an average particle size (D50) ranging from 1 micrometer to 10 micrometers, wherein the coating is present on one or more of the base film or membrane, the ceramic layer, the fiber layer, or a combination(s) thereof.

[0064] The base film or membrane may contain a polymer including, but not limited to, polypropylene (PP), polyethylene (PE), among others, blends, co-polymers, or the like. The base film or membrane may also be in multiple layers.

[0065] The fiber layer can be, for example, a nonwoven (NW), a mesh, a net, or other fiber containing material. Advantages of the fiber layer include, but are not limited to, an increase in base film mechanical strength, reduced splitiness by laminating a fiber layer, improved yield, decreased Hipot failure, enhanced thermal stability, among others.

[0066] The spray coated film can be laminated and / or calendared with the thin fiber layer. The fiber layer varies from 0.1 micrometer to 10 micrometers. The PVDF particles also adhere to the fiber layer to serve as an adhesive. Since the PVDF particles are bigger in size than the fiber thickness, the PVDF can still be used as an adhesive to further laminate with an electrode(s). The fiber serves to increase mechanical strength of the base film and reduce splitness. The fiber layer can also be formed by electro-spin deposition or high voltage melting extrusion. In this way, fiber thickness can be controlled.

[0067] As used herein, PVDF is used to generally refer to PVDF, a PVDF-HFP, or combination thereof. Acrylate particles or agglomerate may also be used. Large particles typically refer to particles or agglomerates with an average particle size (D50) ranging from 1 micrometer to 10 micrometers.

[0068] The composite may be in any of a number of configurations including, but not limited to: membrane / NW / spray coating with large PVDF; ceram ic / membrane / NW / spray coating with large PVDF; spray coating with large PVDF / membrane / NW / spray coating with large PVDF; spray coating with large PVDF / ceramic / membrane / NW / spray coating with large PVDF; NW / membrane / spray coating with large PVDF;NW / membrane / ceramic / spray coating with large PVDF; NW / spray coating with large PVDF / membrane / spray coating with large PVDF; NW / spray coating with large PVDF / membrane / ceramic / spray coating with large PVDF; membrane / ceramic / NW / spray coating with large PVDF; membrane / NW / ceramic / spray coating with large PVDF; membrane / spray coating with large PVDF / NW / ceramic / spray coating with large PVDF; spray coating with large PVDF / NW / membrane / spray coating with large PVDF; spray coating with large PVDF / NW / ceramic / membrane / ceramic / spraycoating with large PVDF; membrane / NW / membrane / spray coating with large PVDF; membrane / NW / membrane / ceramic / spray coating with large PVDF.

[0069] Referring to the figures, Fig. 6 illustrates a composite in accordance with an aspect of the invention. As shown in Fig. 6, a base film or membrane has a thin fiber layer or non-woven on one side. The thin fiber layer is spray coated with large PVDF co-polymer particles. The PVDF co-polymer particles extend above the thin fiber layer and also can extend below into the base film.

[0070] Fig. 7 illustrates a composite in accordance with an aspect of the invention. As shown in Fig. 7, a base film or membrane has a thin fiber layer or non-woven on one side and a ceramic layer on its opposing side. The thin fiber layer is spray coated with large PVDF co-polymer particles. The PVDF co-polymer particles extend above the thin fiber layer and also can extend below into the base film.

[0071] Fig. 8 illustrates a composite in accordance with an aspect of the invention. As shown in Fig. 8, a base film or membrane has a thin fiber layer or non-woven on one side. The thin fiber layer is spray coated with large PVDF co-polymer particles. The PVDF co-polymer particles extend above the thin fiber layer and also can extend below into the base film. The opposing side of the base film or membrane is spray coated with large PVDF co-polymer particles.

[0072] Fig. 9 illustrates a composite in accordance with an aspect of the invention. As shown in Fig. 9, a base film or membrane has a thin fiber layer or non-woven on one side. The thin fiber layer is spray coated with large PVDF co-polymer particles. The PVDF co-polymer particles extend above the thin fiber layer and also can extend below into the base film. The opposing side of the base film or membrane has a ceramic layer. The ceramic layer is spray coated with large PVDF co-polymer particles.

[0073] In regard to the method(s) for making the composite of this embodiment, a spray gun can be used to make a non-continuous coating layer on the base film or one- side ceramic coated film, or two-side ceramic coated film. Ceramic layer thickness varies from 0 micrometers to 10 micrometers. After drying, the adhesive coated layer is about 1 micrometers to 10 micrometers thickness, and the size (the diameter) of each island of PVDF is about 0 mm to 3 mm.

[0074] Among the advantages of the invention are that the large particle of PVDF can absorb a lot of electrolyte to extend battery life cycle. The large particles of PVDF can penetrate an electrode’s porous structure and provide good adhesion. This enables the increased rate of coating and coating processes without having to perform multiple coating runs for the same roll of material, avoiding the risk of damage or contamination.

[0075] Fig. 10 illustrates is a schematic illustration of a side view composite with an extruded fiber layer in accordance with an aspect of the invention. As shown in Fig. 10, a base film or membrane has a thin extruded fiber layer or non-woven layer on at least one side. The thin fiber layer may allow the larger PVDF co-polymer particles to protrude above or thru the fiber layer and part of PVDF particles are still outside of fiber layer and can be used to laminate with the electrodes. As such, the PVDF co-polymer particles extend above the thin fiber layer and also can extend below into the base film. The new coating method may be without water and solvent but with extruded molten fiber on top of the polyolefin base film. The opposing side of the base film or membrane may have a ceramic layer. The ceramic layer may be spray coated with large PVDF copolymer particles.

[0076] Fig. 11 is a SEM surface view image an island or discontinuous adhesive layer in or over a fiber layer in accordance with an aspect of the invention.

[0077] Fig. 12 is a photographic image of a composite in accordance with an aspect of the invention having a base film, fiber layer, and spray coating.

[0078] In accordance with at least certain aspects, objects, or embodiments, disclosed is an inventive or improved non-continuous and water-based adhesive coating containing large polymeric particles or agglomerate with an average particle size (D50) greater than 5 microns. The coating may be applied onto one or both sides of a porous film. A method of forming the coating involves applying an aqueous slurry containing the large polymeric particles with a D50 greater than 5 microns onto a porous membrane. The method of application may be a spray coating method. The method may also include adding a fiber or non-woven layer below, above, or in the adhesive coating, preferably with large adhesive particles protruding therefrom.

[0079] In accordance with at least selected aspects, objects, or embodiments, provided or disclosed is an improved non-continuous and water-based adhesive coatingcontaining large polymeric particles or agglomerate with an average particle size (D50) greater than 5 microns. The coating may be applied onto one or both sides of a porous film. A method of forming the coating involves applying an aqueous slurry containing the large polymeric particles with a D50 greater than 5 microns onto a porous membrane. The method of application may be a spray coating method. The separator may also include a fiber layer or nonwoven on at least one side of the porous membrane. The polymeric particles of the coating may protrude through the fiber layer or nonwoven on at least one side of the porous membrane. The fiber layer may be extruded on the porous membrane or the coating on the porous membrane.

[0080] In accordance with at least certain aspects, objects, or embodiments, provided or disclosed is:A composite, comprising: a porous membrane; and a non-continuous and water-based coating on at least one side of the porous membrane, wherein the coating comprises particles or agglomerates formed from at least one of a low melting point (Tm) polymer having a Tm in a range from about 20°C to about 170°C, a low glass transition temperature (Tg) polymer having a Tgfrom about - 35°C to 60°C, or combinations thereof, and wherein the particles or agglomerates have an average particle size (D50) of from 5 microns to 20 microns.The above composite, wherein the porous membrane is a microporous membrane. The above composite, wherein the porous membrane or the compoisite is a battery separator.The above composite, wherein the particles or agglomerate have a D50 from 5 microns to 15 microns.The above composite, wherein the particles or agglomerate have a D50 from 5 microns to 10 microns.The above composite, wherein the coating comprises particles or agglomerate formed from a low glass transition temperature (Tg) polymer having a Tgfrom about -40°C to 60°C.The above composite, wherein the coating comprises particles or agglomerate formed from a low glass transition temperature (Tg) polymer having a Tg from about -40°C to - 30°C.The above composite, wherein the particles or agglomerate are formed from a PVDF, a PVDF-HFP, or combinations thereof.The above composite, wherein the coating is present on, under, thru, or in the porous membrane, an optional fiber or non-woven layer, or combinations thereof.A composite comprising: a porous membrane; and a water-based non-continuous coating on at least one side of the porous membrane, wherein the coating comprises acrylate particles or agglomerate with a high electrolyte swelling ratio above 200% weight ratio change, or up to above 950% weight ratio change, and with an average particle size (D50) of from 5 microns to 20 microns. The above composite, wherein the acrylate particles or agglomerate have a D50 from 5 microns to 15 microns.The above composite, wherein the acrylate particles or agglomerate have a D50 from 5 microns to 10 microns.A method of forming a non-continuous coating, comprising: applying a water-based slurry onto at least one surface of a porous membrane to form the coating, wherein the slurry comprises polymeric particles or agglomerate having an average particle size (D50) of from 5 microns to 20 microns.The above method, wherein the coating is non-continuous.The above method, wherein the particles have a D50 of from 5 microns to 15 microns. The above method, wherein the particles have a D50 of from 5 microns to 10 microns. The above method, wherein the particles are formed from at least one of a low melting point (Tm) polymer having a Tm in a range from about 20°C to about 170°C, a low glass transition temperature (Tg) polymer having a Tgfrom about -35°C to 60°C, or combinations thereof.The above method, wherein the particles are acrylate particles with a high electrolyte swelling ratio above 200% weight ratio change or up to above 950% weight ratio change.The above method, wherein the water-based slurry is applied using a spray coating method.The above method, wherein the spray coating method is an air spray coating method.The above method, wherein the method is an airless spray method or an air-assisted spray method.The above method, wherein the coating is present on, under, thru, or in the porous membrane, an optional fiber or non-woven layer, or combinations thereof.A composite, comprising: a base film or membrane, a fiber layer, an optional ceramic layer, and a coating comprising large particles or agglomerates containing PVDF, wherein the coating is present on one or more of the base film or membrane, the ceramic layer, the fiber layer, or combinations thereof.The above composite, wherein the coating is a spray coating.The above composite, wherein the large particles or agglomerates of the spray coating have an average particle size (D50) ranging from 1 micrometer to 10 micrometers.The above composite, wherein the fiber layer may be adhered to the base film or membrane by applying a certain pressure from 0.1 Mpa to 20 Mpa to the large adhesive particles from about 25 deg C (or 25°C) to 110 deg C.The above composite, wherein the fiber layer may be extruded, electrospun, laminated, co-extruded, deposited, or the like to or on the base film or membrane or to, in, or on the coating.A composite, comprising: a base film or membrane, a fiber layer, and a coating comprising large particles or agglomerates containing PVDF, wherein the coating is present on, under, thru, or in the base film or membrane, the fiber layer, or combinations thereof.The above composite, wherein the fiber layer may be adhered to the base film or membrane by applying a certain pressure from 0.1 Mpa to 20 Mpa to the large adhesive particles from about 25 deg C to 110 deg C.The above composite, wherein the fiber layer may be extruded, electrospun, laminated, co-extruded, or the like to or on the base film or membrane or to, in, or on the coating. A composite, comprising: a base film or membrane, a coating comprising large particles or agglomerates containing PVDF, wherein the coating is present on, under, thru, or in the base film or membrane, an optional fiber or non-woven layer, or combinations thereof.The above composite, further comprising a fiber or non-woven layer below, above, or in the coating, preferably with large adhesive particles protruding therefrom.The above composite, wherein the fiber or non-woven layer may be adhered to the base film or membrane by applying a certain pressure from 0.1 Mpa to 20 Mpa to the large adhesive particles from about 25 deg C to 110 deg C.The above composite, wherein the fiber or non-woven layer may be extruded, electrospun, laminated, co-extruded, or the like to or on the base film or membrane or to, in, or on the coating.An improved non-continuous and water-based adhesive coating, an ambient or room temperature spray adhesive coating, a room temperature adhesion PVDF coating, or a non-continuous, water-based, spray coated ambient or room temperature adhesion PVDF or PVDF-HFP large particle coating or coated composite with a microporous membrane substrate or base film, and the coating may be on one or both sides and may be over a ceramic coating on one or both sides of the substrate or base film, and the base film or substrate may be a polymer or polyolefin microporous membrane, a polyolefin monolayer microporous membrane, a multilayer polyolefin microporous membrane, a laminated polyolefin microporous membrane, a co-extruded polyolefin microporous membrane, or a combination thereof as shown or described herein. An improved non-continuous and water-based adhesive coating containing large polymeric particles or agglomerate with an average particle size (D50) greater than 5 microns. The coating may be applied onto one or both sides of a porous film ormembrane. A method of forming the coating involves applying an aqueous slurry containing the large polymeric particles with a D50 greater than 5 microns onto a porous membrane. The method of application may be a spray coating method. The coated porous film or membrane may be a battery separator. The coated porous film or membrane may include a fiber layer on at least one side. The fiber layer can be adhered to a porous film or membrane (such as a wet PE, dry PP, dry PP / PE / PP trilayer, etc.) by coating layers with pressure activated at different temperature from 25 deg C to 110 deg C or may be extruded, electrospun, laminated, co-extruded, or the like to or on the porous film or membrane or to, in, or on the coating.

[0081] The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of the invention.

Claims

CLAIMS1 . A composite, comprising: a porous membrane; and a non-continuous and water-based coating on at least one side of the porous membrane, wherein the coating comprises particles or agglomerates formed from at least one of a low melting point (Tm) polymer having a Tmin a range from about 20°C to about 170°C, a low glass transition temperature (Tg) polymer having a Tg from about -35°C to 60°C, or combinations thereof, and wherein the particles or agglomerates have an average particle size (D50) of from 5 microns to 20 microns.

2. The composite of claim 1 , wherein the porous membrane is a microporous membrane.

3. The composite of claim 1 , wherein the porous membrane or the compoisite is a battery separator.

4. The composite of claim 1 , wherein the particles or agglomerate have a D50 from 5 microns to 15 microns.

5. The composite of claim 1 , wherein the particles or agglomerate have a D50 from 5 microns to 10 microns.

6. The composite of claim 1 , wherein the coating comprises particles or agglomerate formed from a low glass transition temperature (Tg) polymer having a Tgfrom about - 40°C to 60°C.

7. The composite of claim 1 , wherein the coating comprises particles or agglomerate formed from a low glass transition temperature (Tg) polymer having a Tg from about - 40°C to -30°C.

8. The composite of claim 1 , wherein the particles or agglomerate are formed from a PVDF, a PVDF-HFP, or combinations thereof.

9. A composite comprising: a porous membrane; and a water-based non-continuous coating on at least one side of the porous membrane, wherein the coating comprises acrylate particles or agglomerate with a high electrolyte swelling ratio above 200% weight ratio change, or up to above 950% weight ratio change, and with an average particle size (D50) of from 5 microns to 20 microns.

10. The composite of claim 9, wherein the acrylate particles or agglomerate have a D50 from 5 microns to 15 microns.11 . The composite of claim 9, wherein the acrylate particles or agglomerate have a D50 from 5 microns to 10 microns.

12. A method of forming a non-continuous coating, comprising: applying a water-based slurry onto at least one surface of a porous membrane to form the coating, wherein the slurry comprises polymeric particles or agglomerate having an average particle size (D50) of from 5 microns to 20 microns.

13. The method of claim 12, wherein the coating is non-continuous.

14. The method of claim 12, wherein the particles have a D50 of from 5 microns to 15 microns.

15. The method of claim 12, wherein the particles have a D50 of from 5 microns to 10 microns.

16. The method of claim 12, wherein the particles are formed from at least one of a low melting point (Tm) polymer having a Tm in a range from about 20°C to about 170°C, a low glass transition temperature (Tg) polymer having a Tgfrom about -35°C to 60°C, or combinations thereof.

17. The method of claim 12, wherein the particles are acrylate particles with a high electrolyte swelling ratio above 200% weight ratio change or up to above 950% weight ratio change.

18. The method of claim 16, wherein the water-based slurry is applied using a spray coating method.

19. The method of claim 18, wherein the spray coating method is an air spray coating method.

20. The method of claim 18, wherein the method is an airless spray method or an airassisted spray method.

21. The method of claim 12, wherein the coating is present on, under, thru, or in the porous membrane, an optional fiber or non-woven layer, or combinations thereof.

22. A composite, comprising: a base film or membrane, a fiber layer, an optional ceramic layer, and a coating comprising large particles or agglomerates containing PVDF, wherein the coating is present on one or more of the base film or membrane, the ceramic layer, the fiber layer, or combinations thereof.

23. The composite of claim 22, wherein the coating is a spray coating.

24. The composite of claim 23, wherein the large particles or agglomerates of the spray coating have an average particle size (D50) ranging from 1 micrometer to 10 micrometers.

25. A composite, comprising: a base film or membrane, a fiber layer, and a coating comprising large particles or agglomerates containing PVDF, wherein the coating is present on, under, thru, or in the base film or membrane, the fiber layer, or combinations thereof.

26. A composite, comprising: a base film or membrane, a coating comprising large particles or agglomerates containing PVDF, wherein the coating is present on, under, thru, or in the base film or membrane, an optional fiber or non-woven layer, or combinations thereof.

27. The composite of claim 26, further comprising a fiber or non-woven layer below, above, or in the coating, preferably with large adhesive particles protruding therefrom.

28. The composite of claim 26, wherein the fiber or non-woven layer may be adhered to the base film or membrane by applying a certain pressure from 0.1 Mpa to 20 Mpa to the large adhesive particles from about 25 deg C to 110 deg C.

29. The composite of claim 26, wherein the fiber or non-woven layer may be extruded, electrospun, laminated, co-extruded, deposited, or the like to or on the base film or membrane or to, in, or on the coating.

30. The composite of claim 22, wherein the fiber layer may be adhered to the base film or membrane by applying a certain pressure from 0.1 Mpa to 20 Mpa to the large adhesive particles from about 25 deg C to 110 deg C.31 . The composite of claim 22, wherein the fiber layer may be extruded, electrospun, laminated, co-extruded, or the like to or on the base film or membrane or to, in, or on the coating.

32. The composite of claim 25, wherein the fiber layer may be adhered to the base film or membrane by applying a certain pressure from 0.1 Mpa to 20 Mpa to the large adhesive particles from about 25 deg C to 110 deg C.

33. The composite of claim 25, wherein the fiber layer may be extruded, electrospun, laminated, co-extruded, or the like to or on the base film or membrane or to, in, or on the coating.

34. The composite of claim 1 , wherein the coating is present on, under, thru, or in the porous membrane, an optional fiber or non-woven layer, or combinations thereof.

35. An improved non-continuous and water-based adhesive coating, an ambient or room temperature spray adhesive coating, a room temperature adhesion PVDF coating, or a non-continuous, water-based, spray coated ambient or room temperature adhesion PVDF or PVDF-HFP large particle coating or coated composite with a microporous membrane substrate or base film, and the coating may be on one or both sides and may be over a ceramic coating on one or both sides of the substrate or base film, and the base film or substrate may be a polymer or polyolefin microporous membrane, a polyolefin monolayer microporous membrane, a multilayer polyolefin microporous membrane, a laminated polyolefin microporous membrane, a co-extruded polyolefin microporous membrane, or a combination thereof as shown or described herein.

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