Functionalized lead acid battery separators, improved lead acid batteries, and related methods

Abstract

A lead acid battery separator comprises on a surface thereof a layer of oil and an oxidation resistant material, the oxidation resistant material and oil being released from the surface of the lead acid battery separator into the battery. Oxidation resistance is provided by depositing aluminum oxide and silicon dioxide on the positive electrode surface of the separator; reduction of black residue is provided by using less oil on one or both sides of the bulkhead; the separator is provided with stiffness by depositing alumina and silica on one or both sides of the separator. The porous polyolefin film of the battery separator comprises an extruded mixture comprising about 30% by weight of an inert material. According to the invention, it has improved charge acceptance, improved surface conductivity, improved oxidation resistance, reduced acid stratification, improved resistance to oxidation caused by metal contamination, reduced black residue, improved wettability and / or improved stiffness.

Description

[0001] This application is a divisional application in light of the singleity issue pointed out in the “Notice of First Office Action” (Notice No. 2023042700057680) issued by the State Intellectual Property Office on April 27, 2023. The original application date is October 5, 2016; the original application number is 202210356086.6; and the original invention title is “Functionalized Lead Acid Battery Separator, Improved Lead Acid Battery and Related Methods”.

[0002] Cross Reference to Related Applications

[0003] This application claims priority to and the benefit of U.S. Provisional Patent Application Serial No. 62 / 237,174, filed October 5, 2015. The entire contents of the above-identified application are incorporated herein by reference. TECHNICAL FIELD

[0004] According to at least selected embodiments, the present application or invention relates to a new, improved or optimized porous thin film, membrane or substrate, a functionalized, coated or treated porous thin film, membrane or substrate, a new, improved, optimized, functionalized, coated or treated separator, separator plate, multi-layer separator plate, lead acid battery separator or composite, an electrochemical device, battery or battery cell comprising such thin film, membrane, substrate, separator, separator plate, lead acid battery separator or composite, a new, improved or optimized plate or electrode assembly or system having such thin film, membrane, substrate, separator, separator plate, lead acid battery separator or composite, a method of making such thin film, membrane, substrate, separator, separator plate, lead acid battery separator, composite, system, assembly, battery cell, device and / or battery, and / or a method of using such thin film, membrane, substrate, separator, separator plate, lead acid battery separator, composite, system, assembly, battery cell, device and / or battery. According to at least certain embodiments, the present application relates to a new, improved or optimized, functionalized, coated or treated microporous membrane, battery separator, lead acid battery separator, separator plate and / or lead acid battery separator having at least one functionalized, coated or treated surface on at least one side, a lead acid battery separator having at least one coating, thin film, layer or material on at least one side, rib or surface, an energy storage device, battery cell, system, assembly and / or battery comprising such membrane, battery separator, lead acid battery separator, separator plate and / or lead acid battery separator, a method of making such membrane, battery separator, lead acid battery separator, separator plate and / or lead acid battery separator, and / or a method of using such membrane, battery separator, lead acid battery separator, separator plate, lead acid battery separator, composite, assembly, system, device, battery cell and / or battery, etc. BACKGROUND

[0005] Lead acid batteries have four basic components: a positive electrode, which can be a lead or lead alloy grid coated with a positive active material (PAM) coating; a negative electrode, which can be a lead or lead alloy grid coated with a negative active material (NAM) coating; a separator; and a liquid electrolyte, typically sulfuric acid. To prevent physical contact between electrodes of opposite polarity while allowing ion flow, an electrically insulating, porous separator is placed between the electrodes. The separator typically includes a microporous polymer film or material, such as a polyolefin film, such as a polyethylene (PE) film. In lead acid batteries, the area where the electrolyte and positive electrode meet is referred to as the interface “oxidation zone.” The oxidation can be purely chemical or purely electrochemical or a combination of both. This oxidation zone is on the order of a few hundred micrometers or pm, extending into the electrolyte where the separator is placed. Polyethylene and similar polymers do not have inherent resistance to oxidation during battery operation, so accelerated oxidation can occur, particularly in the portion of the separator located in the oxidation zone. Oxidation of the separator material can result in reduced battery performance and life.

[0006] Typical separators are generally constructed in a pouch, bag, or sleeve configuration around either or both of the positive or negative electrodes. The pouch or sleeve is obtained from a single sheet of separator material that is folded into the shape required to surround the electrodes. This folding and cutting is typically performed continuously in automated equipment. Over time, automotive battery manufacturers have reduced the backweb thickness of the separator from 250 pm to 150 pm, as reducing the volume of the separator allows additional electrolyte and electrode material to be present in the battery, thereby increasing power and performance. However, because bending stiffness is related to the cube of the thickness, even a small reduction in thickness can significantly reduce the bending stiffness. For example, a 30% reduction in thickness can result in a 70% reduction in bending stiffness. The reduced stiffness of the separator presents manufacturing challenges with existing equipment. For example, the reduced stiffness increases the propensity for inadvertent folding and creasing, resulting in a higher scrap rate of finished separators. Reducing the production speed can reduce the scrap rate, but the loss of productivity that accompanies such a reduction in speed is often not commercially desirable or feasible.

[0007] When a lead acid battery is deeply discharged, the gravity of the electrolyte decreases as the sulfuric acid participates in the energy storage reaction. Upon recharging, a higher density of pure sulfuric acid is created at the electrode surface (i.e., the boundary layer) than in the bulk electrolyte. In the boundary layer, only the outer sulfuric acid will diffuse into the bulk electrolyte, while the remaining sulfuric acid, being heavier than the electrolyte, will collect at the bottom of the battery. This separation of the sulfuric acid from the bulk electrolyte is referred to as “acid stratification.” The reduced level of acid at the top of the battery inhibits plate activation and increases corrosion. Moreover, the increased concentration of acid at the bottom artificially raises the voltage of the battery, which can interfere with the battery management system. Overall, acid stratification results in higher resistance, leading to reduced battery life.

[0008] Accordingly, there is a need for improved separators and / or batteries. For example, there can be a need for improved separators or batteries that can provide improved or enhanced charge acceptance, surface conductivity, oxidation resistance, wettability, bending stiffness, and / or cycle life, and / or reduced acid stratification; a need for a battery, particularly a lead acid battery, that has improved charge acceptance and / or reduced acid stratification; a need for a battery separator that has improved wettability, improved surface conductivity, improved oxidation resistance, and / or increased stiffness; and / or a need for a manufacturing process that allows for rapid production of battery components, including separators, with reduced scrap rates of finished separators. SUMMARY

[0009] According to at least selected embodiments, aspects, or objects of the present application or invention, novel or improved separators, batteries, and / or methods can meet the above needs, can meet the need for improved separators that can provide improved or enhanced charge acceptance, surface conductivity, oxidation resistance, wettability, bending stiffness, and / or cycle life, and / or reduced acid stratification; can meet the need for improved batteries, particularly lead acid batteries, that have enhanced charge acceptance and / or reduced acid stratification, the need for improved battery separators that have improved wettability, improved surface conductivity, improved oxidation resistance, and / or increased stiffness; and / or can meet the need for improved manufacturing processes that allow for rapid production of battery components, including separators, with reduced scrap rates of finished separators, and / or can provide novel or improved separators, batteries, and / or methods, and / or can provide improved or enhanced charge acceptance, surface conductivity, oxidation resistance, and / or cycle life, reduced acid stratification, improved resistance to abuse or contamination, improved resistance to oxidation caused by metal contamination, reduced black staining, improved wettability, increased stiffness, increased service life of the separator, or combinations thereof.

[0010] According to at least one embodiment, aspect, or object of the present application or invention, oxidation of the separator is prevented to enhance, improve, or maintain a desired cycle life of the battery, a serviceable life of the separator, or both.

[0011] According to at least one embodiment, aspect, or object of the present application or invention, the layer of harder material on the top of the substrate can replace increasing the stiffness of the separator body, thereby avoiding a possible hard, brittle separator body.

[0012] According to at least certain embodiments, the battery separators described herein are directed to multi-layer or composite microporous membrane battery separators that can have superior oxidation resistance and be stable in lead acid battery systems. According to at least other selected embodiments, the present invention is directed to a battery separator having a layer that increases oxidation resistance, improves oxidation resistance in the presence of metal ion contaminants such as chromium ions, reduces acid stratification, improves surface conductivity, improves charge acceptance, increases stiffness and processability, and / or increases surface wettability.

[0013] According to at least certain selected embodiments, the present invention is directed to a separator for a battery that is a microporous polymer membrane that is functionalized, coated, treated, etc. to apply at least one material, treatment, function or layer to at least one side thereof. In certain selected embodiments, the material, treatment, function or layer can or can not include an adhesive, can include one or more materials such as silica, silicon oxide, alumina, aluminum oxide, metals, metal oxides, conductive carbon materials, acid stable cellulose and / or the like, and / or can include one or more electrically conductive or non-conductive or insulating layers.

[0014] According to at least certain embodiments, a method is provided for obtaining an improved separator that applies a treatment, material or layer to at least one surface or side of a polymeric microporous membrane, a polyethylene (PE) microporous membrane, a woven or nonwoven material, a nonwoven glass mat, a nonwoven absorbent glass mat (AGM), a nonwoven or woven

[0015] PET, cellulose nonwoven felt and / or the like. The material, treatment or layer can be applied by vapor deposition, chemical deposition, vacuum assisted methods, PVD, CVD, TD, DCD, PACVD, DLC, thin film coating or deposition techniques, nanofilm techniques, monatomic thick coating techniques, sol-gel, solvent coating, aqueous coating, etc. In some embodiments, the material, treatment, coating, layer or function is applied or added by a solventless method, a binderless method or a solventless and binderless method. In other selected embodiments, the layer is applied in the presence of a binder and / or solvent that can be subsequently removed by post processing.

[0016] According to at least selected embodiments, a porous membrane having a porous or ionically conductive coating or layer is provided as a battery separator in a lead acid battery that can improve the cycle life, starting ability and high charge acceptance of the battery.

[0017] According to at least certain embodiments, the battery separators described herein relate to multi-layer or composite microporous membrane battery separators that can have superior oxidation resistance and be stable in lead acid battery systems. According to at least other alternative embodiments, the present invention relates to a battery separator having a layer that increases oxidation resistance, increases oxidation resistance in the presence of metal ion contaminants such as chromium ions, reduces acid stratification, improves surface conductivity, improves charge acceptance, increases stiffness, runnability and processability, and / or increases surface wettability. One method for providing oxidation resistance to a polymer separator is through the sacrificial oxidation of residual oil. During the wet formation of polyethylene (PE) separators, oil (plasticizer) such as mineral oil is used as a pore former. When residual oil remains on the separator, it can act as a sacrificial oxidizing species. Residual oil can typically be present in the separator matrix at a concentration of about 8% to 20% by weight. This agent / oil acts as a sacrificial agent or component that oxidizes before the polyethylene, thereby reducing the rate at which the separator itself is oxidized. However, after oxidation, the sacrificial oil or material can be released from the separator and can appear as a dark or black residue or film on the top of the electrolyte. In addition, a layer of oxidation resistant material can replace a percentage of the oil in the separator, thereby reducing the black residue problem.

[0018] According to at least certain embodiments, aspects or objects, the present application or invention can address the needs or problems described above, and / or can provide at least one coating, layer or material on at least one surface, rib, side or portion of a polymeric microporous membrane. According to at least certain embodiments, a coating, layer, film, treatment, deposit or material that imparts improved oxidation resistance, reduced black staining, improved wettability, improved surface conductivity and / or increased stiffness to a separator is described. According to at least certain embodiments, a battery, particularly a lead acid battery, having improved cycle life, charge acceptance and / or reduced acid stratification is described.

[0019] According to at least certain embodiments, a method for making a porous membrane having a coating, layer or material that can impart one or more of the above desired properties, performance or characteristics is disclosed. In some embodiments, the coating, layer or material includes one or more layers of electrically conductive or electrically insulating materials, such as silica, alumina, metals, metal oxides, conductive carbon materials, cellulose, mixtures thereof, multilayers and / or the like.

[0020] Oxides are generally electrically non-conductive: e.g., silica, silicon oxide, alumina and aluminum oxide (silica is a common term for silicon oxide, alumina is a common term for aluminum oxide).

[0021] Metals, metal oxides and carbon can all be electrically conductive or partially conductive or semiconductive.

[0022] The separator is typically electrically non-conductive (an insulator), but is porous and wetted with electrolyte, allowing ionic conduction through during charging and discharging of the battery. Certain materials can be electrically insulating (non-conductive), but can be thermally conductive (e.g., alumina).

[0023] In certain selected embodiments, the coating, layer or material is disposed on the surface of the porous membrane facing the positive electrode, in other embodiments, the coating, layer or material (or a different coating, layer or material) is disposed on the surface of the porous membrane facing the negative electrode. In certain embodiments, the coating, layer or material (or a different coating, layer or material) is disposed on both surfaces (or sides, top and bottom surfaces, positive and negative surfaces) of the porous membrane or separator. In some selected embodiments, the porous membrane is disposed as an envelope or sleeve, and the coating, layer or material can be on the outer surface, inner surface or both surfaces of the envelope or sleeve.

[0024] In certain selected embodiments, a layer on the side, surface, rib or portion of the microporous battery separator is provided, such as in lead acid batteries, the layer can be preferably oxidation resistant (more oxidation resistant than the base film, substrate or membrane), present on at least one side of the separator facing the positive electrode, for example, on the interface of the separator and positive electrode (or adjacent to the positive electrode or glass mat of the plate or PAM), and in certain lead acid batteries or cells, it can also be stable at cell potentials of at least about 2.1, 2.2, 2.5 or 2.7 V (volts) or higher.

[0025] According to certain embodiments, the separators described herein relate to microporous battery separators having at least one layer or deposit comprising at least one material, such as silica, silicon oxide, alumina, aluminum oxide, a metal, a metal oxide, a conductive carbon material, mixtures or blends thereof, and the like, the thickness of the deposit or layer (or multiple deposits and / or multiple layers) is in the range of 0.1 pm to 250 pm. Microporous membranes in lead acid batteries having at least one layer containing silica, silicon oxide, alumina, aluminum oxide, a metal, a metal oxide, a conductive carbon material, cellulose, a cellulose material, mixtures or blends thereof, and / or the like, can enable separators to have the same or better target performance, characteristics or properties as separators coated with other materials and / or with residual oil without such a layer or coating.

[0026] The coatings used herein can be inert or reactive. Reactive materials can undergo an initial reaction, for example in the presence of oxygen, electrolytes, electromagnetic radiation (e.g. UV), or thermal energy input, which results in a chemical change at or across the surface of the coating or layer. The coating, layer, or material on the substrate or membrane can be a deposited or applied process starting material, or can be a reacted (altered) material that is or constitutes a coating or layer on the surface of the membrane. Moreover, the concentration of the desired material of the coating or layer can vary (possibly with a concentration or density gradient facing or away from the surface). In certain selected embodiments, the coating or layer as described herein can be very thin and contribute very little additional thickness to the overall thickness of the porous membrane or substrate, but can provide oxidation resistance and / or stiffness equivalent to a thicker oxidation resistant porous membrane. In certain embodiments, the coating or layer as described herein can be a multi-layer stack of different materials. In certain selected embodiments, the separators of the present invention contain much less processing oil than conventional separators because the coating of the present invention reduces the need for a sacrificial agent to prevent oxidation of the separator. In certain selected embodiments, the separator contains very little or no processing oil, or no processing oil on the surface.

[0027] In certain selected embodiments, the coating, layer, material, and / or the like of the present invention can increase the wettability of the separator. Conventional polyolefin separators typically have a relatively hydrophobic surface due to crystallinity and polymer condensation that occurs at the surface of conventional separators. In certain selected embodiments, the coating material of the present invention is a porous hydrophilic material that optionally penetrates the surface of the polymeric hydrophobic separator. See Figure 7 and 7A However, due to the penetration of the coating material or high energy beam or ion beam plasma (e.g. in physical vapor deposition (PVD)), the surface itself can be hydrophilic, can cause the coating components to themselves embed into the surface forming a gradient interface, which can help better adhere the coating to the substrate, and / or it can form an extended interface with better properties, e.g. better hydrophilicity, on the porous membrane or substrate hydrophobic surface, thereby increasing the wetting rate (to water or sulfuric acid) of the treated, coated, or modified separator. In some cases, the penetration occurs simultaneously with the application of the coating on the porous membrane, in other embodiments, the penetration is achieved by compression, calendering, heat treatment, or other physical means after the coating material or deposition is applied to help interface diffusion. One possible coating material or component is a cellulosic or cellulose, particularly or possibly preferably on the positive face (the side facing the positive plate or electrode) of the substrate or separator.

[0028] In at least some embodiments, the coating materials of the present application can be electrically conductive and can provide enhanced current distribution through the polymeric microporous membrane. This enhanced distribution can improve the electronic interaction with the active material or PAM such as Pb02, thereby increasing the rate of lead sulfate (formation) or reduction, thereby increasing the ability of the battery to accept higher charge rates (i.e., improve charge acceptance). By having a partially conductive insulating film (e.g., silica or alumina) on the surface of the insulating polymeric film, ionic conduction from the Pb02to the separator should occur easily. Having one or more layers or coatings as an interface to reduce the barrier to ion diffusion should be able to increase the surface conductivity, charge acceptance, and cycle life. The coating or layer of the present application can reduce the interfacial barrier between the conductive positive plate active material (PAM) and the insulating polymeric separator or substrate. For example, consider the addition of carbon, metal, conductive or semiconductive materials on the polymeric based film or membrane or on the silica coating or layer on the polymeric based film, substrate or membrane (one or more transition layers).

[0029] Various ceramic particle containing coatings, ceramic coatings, inorganic coatings, organic coatings, inorganic and organic coatings, and / or polymeric coatings for microporous battery separators can provide improvements in safety, battery cycle life, and / or performance. Such coatings can include one or more polymers, inorganic or organic polymers or polymeric materials, polymeric binders, one or more types of inorganic or organic particles, inorganic ceramic particles, and water-based or non-water solvents. Such coatings can be applied using various techniques such as, but not limited to, PVD, CVD, sol-gel, dip coating, doctor blade, gravure, curtain coating, spray coating, and the like.

[0030] There is a need for improved battery separators to address some or all of the above needs, difficulties, or problems. For example, there is a need for batteries, particularly lead acid batteries, that have improved charge acceptance and / or reduced acid stratification. There is a need for battery separators that have improved wettability, improved surface conductivity, improved oxidation resistance, and / or increased stiffness. There is a need for manufacturing processes that allow for the rapid production of battery components, including separators, that reduce the scrap rate of finished separators.

[0031] In at least some embodiments, the coatings as described herein can react with atmospheric oxygen or electrolyte (sulfuric acid) to form a passivation layer. The passivation layer can be oxidation resistant and can provide an additional layer of protection on the surface of active metals (e.g., aluminum) from oxidation. Once the passivation layer is formed, a higher level of oxidation stability of the improved separator can be achieved. In other embodiments, the passivation layer can be obtained by subjecting the coating to heat, UV, or other energy input.

[0032] According to at least selected embodiments, the present application or invention relates to new or improved porous membranes or substrates, separators, separators, composites, electrochemical devices, batteries, methods of making such membranes or substrates, separators and / or batteries, and / or methods of using such membranes or substrates, separators and / or batteries. According to at least certain embodiments, the present application relates to new or improved microporous membranes, battery separators, separators, energy storage devices comprising such separators, batteries, methods of making such membranes, separators and / or batteries, and / or methods of using such membranes, separators and / or batteries. According to at least certain selected embodiments, the present invention relates to a separator for a battery having an oxidation protection and binderless deposition layer that is stable at least at 2.1, 2.2, 2.5 or 2.7 volts, or even higher in certain lead acid batteries or cells. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a schematic vertical cross-sectional view of a conventional positive plate and an adjacent battery separator, such as a microporous PE separator separator.

[0034] Figure 2 is a schematic vertical cross-sectional view of a positive plate and a functionalized separator of the present invention having at least one functional coating, material, layer or deposit on at least one side (face) of a porous substrate, membrane or film, such as a microporous PE separator or membrane separator.

[0035] Figure 3 is a schematic vertical cross-sectional view of a positive plate and another functionalized separator of the present invention having at least two functional coatings, layers, deposits and / or materials on at least one side of a porous substrate, membrane or film, such as a microporous PE membrane separator. For example, coating A can be carbon or alumina and coating B can be silica.

[0036] Figure 4 is a schematic vertical cross-sectional view of a positive plate and another functionalized separator of the present invention having at least one functional coating, layer, deposit and / or material on each side of a porous substrate, membrane or film, such as a microporous PE membrane separator. For example, coating C can be carbon, silica or alumina and coating D can be carbon or silica.

[0037] Figure 5A and "Table 1" are tables of non-limiting exemplary embodiments read in conjunction with the description below. Figure 5A continued

[0038] is another table of non-limiting exemplary embodiments read in conjunction with the description below. Figure 5B

[0039] is a schematic view of a positive plate and a separator. Figure 6

[0040] ​Figure 7 is a schematic view of a coated or treated separator of the present invention having a surface coating, layer or treatment on one side.

[0041] Figure 7A is a partially enlarged schematic view of Figure 7 and the associated concentration profile, showing a coated or treated separator of the present invention having a surface coating or treatment on one side, the coating or treatment material penetrating into the membrane or substrate and having a higher concentration of material in the direction of the outer surface facing the coating, layer or treatment. DETAILED DESCRIPTION

[0042] Embodiments of the claimed invention will now be discussed in detail. Certain terminology and phrases will be used that are well known in the art and / or are defined as follows.

[0043] Oxidation Resistance—

[0044] The oxidation zone in a lead acid battery is located at the interface between the positive electrode, which can be a lead or lead alloy grid, to which positive active material (PAM), which can be PbO2, is adhered, and the electrolyte, which can be sulfuric acid. The oxidation zone is on the order of a few hundred microns and extends into the electrolyte where the separator is placed. It is apparent that if the separator is in contact with the positive electrode, the membrane will be oxidized. In at least one embodiment, it is considered necessary to provide oxidation resistance as one of the preferred features of the separators of the present invention. In general, polymers do not have oxidation resistance. Different methods or layers are disclosed herein to provide oxidation resistance to the polymeric separators.

[0045] Sacrificial Material in the Separator—

[0046] Polyethylene separators are the predominant material used globally for flooded lead acid batteries. To protect the polyethylene from the oxidative attack that occurs in lead acid batteries, residual pore former or oil is left in the separator substrate to the extent of 8% to 20% by weight. The oil will oxidize before the polyethylene as a sacrificial material. However, after oxidation, the oil is likely to be released from the separator and can appear as a black film or residue on top of the electrolyte.

[0047] Glass Mat as an Interlayer—

[0048] A thin layer of glass fiber mat can be attached or placed between the polymeric separator and the positive electrode. Glass in lead acid batteries is not oxidized by the electrochemical potential or the acid. This glass mat, in contact with the positive electrode, will not oxidize like the polymer.

[0049] The present invention adds a coating as a means to, for example, improve the oxidation resistance of the PE separator, replace the glass mat, or allow for the removal or substantial reduction of the oil that acts as a pore former, thereby minimizing the potential for black residue, reducing impediments to ion diffusion, increasing surface conductivity, enhancing or facilitating charge acceptance, reducing acid stratification, and the like. The coating can include polymers, binders, particles, fibers, and / or the like.

[0050] Rigidity or processability—

[0051] In the production of automotive batteries, the PE separator typically envelopes the positive and / or negative plates. This envelope is accomplished in a continuous fashion with automated equipment. Traditionally, the separator has not been a typical failure mode of the automotive battery, and as such, the thickness of the separator has been gradually reduced over the years, moving from 250 pm to as low as 150 pm back web thickness for automotive battery manufacturers. Since the bending stiffness is related to the cube of the thickness, a 30% reduction in thickness can result in a 70% reduction in bending stiffness, the bending stiffness is greatly reduced, making the separator more challenging to process on existing equipment. This also increases the potential for unintentional folding and creasing, causing more product to be rejected on the automated equipment or having to be run at greatly reduced speeds, which reduces productivity. Thus, the present invention can also provide a means to achieve a thinner, increase run speeds, or improve bending stiffness, and / or provide a method to improve the bending stiffness of the separator, or any combination thereof.

[0052] Surface conductivity—

[0053] Current passes through the positive or negative grid into the active material (PAM or NAM). It is well known that the active material either extends the grid vertically, horizontally, or laterally, or even to the depth of the electrode and occupies a different distance from the grid. Thus, the conversion rate of the active material is not uniform, but can be a function of the distance from the current collector. Thus, the idea is to make the surface of the separator or associated plies conductive so that the electrons will have an alternative path to flow and react with the active material. The degree to which this can be achieved reflects a more efficient use of the active material in both conversion rate and utilization in the energy storage reaction. Thus, described herein are means and methods to improve the charge acceptance of the battery through improvements to the separator.

[0054] Acid stratification—

[0055] When a lead acid battery is deeply discharged, the gravity of the electrolyte will drop, as the sulfuric acid is also a participant in the energy storage reaction. Upon recharging, pure sulfuric acid will be generated at the electrode surface, which is heavier than the bulk electrolyte gravity. Since this sulfuric acid boundary layer is generated at the electrode surface, it will create a boundary layer that only the outer layer of sulfuric acid will diffuse into the bulk electrolyte, while the remaining boundary layer will be subject to gravity and accumulate at the bottom of the battery. As the battery is overcharged, gas bubbles will nucleate and rise to the top of the battery, taking some of the sulfuric acid with them, thereby creating a mixing effect within the battery to at least partially overcome the acid stratification. If the battery is not fully charged, the stratified acid will have a detrimental effect on the electrochemical performance of the battery going forward, as it is inside the battery but not in the right place, or not properly dispersed to react with the active material as a whole. Accordingly, embodiments of the present invention provide a means and / or method for reducing or destroying the boundary acid generated at the electrode surface, and / or allowing acid mixing, and / or preventing acid stratification without the use of overcharging and evolution of synthetic gases.

[0056] Improved separator wettability

[0057] It has been found that the surface of a PE separator generally has some degree of hydrophobicity, as the PE separator has a polymer-rich surface due to the nature of crystallinity and polymer condensation. This polymer-rich layer can be only a few microns thick, and once it is penetrated, the highly porous separator matrix underneath has sufficient hydrophilicity. Due to this situation, a hydrophilic surfactant is generally applied to the separator surface or substrate to overcome this situation. In preferred embodiments, a means and / or optional method for wetting the surface of the separator substrate is provided.

[0058] All of the above embodiments of the present invention have one thing in common, which is to form, coat or deposit, or laminate a layer (or layers) of functional material on the surface of the separator, to enhance the performance of the separator and the battery in which the separator is placed, to improve the battery productivity, etc., and any combination thereof. Thus, it has been unexpectedly found that various functional materials can be applied to a lead acid battery separator adjacent to PAM, NAM or both, by vapor deposition, chemical deposition, solvent coating, aqueous coating and various combinations, with or without the use of glass mat. In certain embodiments, it can be preferred that the added layer or layers can be in the range of 0.1 pm to 250 pm, possibly preferably about 5 pm to about 75 pm per layer or combination.

[0059] The coating can be a mixture of fibers (such as glass fibers) and particles (such as silica), where the glass fibers are resistant to acid stratification in addition to oxidation. This can be achieved by coating a sol-gel material mixture containing glass fibers, silica and a binder, dispersing the dispersion medium or solvent by roll coating or spraying, and then drying the dispersion medium (e.g. water). The binder binds the composite material together and to the substrate.

[0060] Antioxidation and black residue—

[0061] Since the deposited silica has inherent porosity in structure and is inert to oxidative attack that can occur in lead acid batteries, it is proposed to deposit a thin layer of silica on the surface of the separator or polymeric membrane or substrate. It can be preferred that the manner of deposition of the silica can be such that the resulting substructure is still porous and inherently adhered to the separator surface.

[0062] In service, the back web, ribs and / or substrate can inadvertently come into contact with the positive electrode. During charging, especially during overcharging, nascent oxygen or oxidizing species can be generated at the electrode surface. When they come into contact with the separator, the exposed polymeric separator surface can be oxidized, especially the polymer that binds the components of the separator together. Given enough time, these oxidizing species can actually create splits and cracks in the separator, which can eventually lead to an electronic conductive path between the positive and negative electrodes, which can short the battery.

[0063] With the silica antioxidation layer on the surface of the separator, a number of functions can be created. First, the residual pore former or oil can be greatly reduced, since it is no longer needed to protect the polymer, as that function has been switched to the silica layer. With the reduction in the presence of residual pore former in the separator, the tendency for black residue can be reduced. With the increase in antioxidation, the substrate or back web thickness can be further reduced without fear of failure due to oxidation, cracking, splitting, tearing or any combination thereof.

[0064] Rigidity, runnability and processability—

[0065] The body of a lead acid battery separator is a three-dimensional structure, comprising a substrate or back web of given thickness and a three-dimensional shape, such as continuous trapezoids or ribs that protrude from the substrate surface. Because of this arrangement, the lowest bending resistance is found in the direction perpendicular to the ribs. Since separators are typically sold in roll form, if very thin, they can be prone to folding, wrinkling or becoming skewed due to substrate deformation in the width or transverse direction (CMD) of the separator. One method to improve the bending resistance or rigidity in the CMD is to deposit a low bending resistance material or semi-rigid material. One embodiment deposits a layer of carbon or silica, and the resulting web will not be prone to bending, but will actually be substantially rigid. This rigidity can be enhanced by the degree of packing of the individual particles and the thickness of the layer or layers deposited on the substrate.

[0066] One possible preferred embodiment is to deposit a continuous hardening layer on either side (or both sides) of the separator, regardless of whether the coating is facing the negative electrode or the positive electrode. The rigidity can be enhanced even if the layer of these materials is not deposited in a continuous layer, but in a peeling or cross-hatched form.

[0067] Improved separator wetting—

[0068] To improve the wetting of the separator in the absence of surfactants, it is proposed to deposit a thin layer of highly porous silica on the surface of the separator. This deposited silica can require some additional calendering force to actually penetrate the polymer rich layer to improve the rate of wetting of the separator.

[0069] Surface conductivity—

[0070] To improve the surface conductivity, it is envisioned to deposit a carbon structure (e.g. graphite, graphene, carbon, CNT, etc.) with sufficient electrical conductivity onto the surface of the separator facing the negative electrode, or onto the ribs facing the positive electrode surface, or onto the laminate, or AGM separator in direct contact with the positive plate. As the lead acid battery discharges, a layer of lead sulfate forms on the electrode surface that is relatively non-conductive with respect to the surrounding lead. Since the above mentioned materials with conductive layers will be in contact with the electrode, this will allow any surface charge to be transported via the now found conductive path on the separator and thus reduce the sulfate layer in a more efficient manner. It is important to note here that the path of electrical conductivity is primarily created in the X and Y plane of the separator and not completely through the Z plane. If the electronic conductivity is achieved through the Z plane, then there will be electronic conduction and the separator will cease to perform its function as this will short the battery. By creating an alternative path of electrical conductivity in the X and Y plane, it is envisioned to improve the speed of lead sulfate reduction and thus the ability to receive higher charge rates, which is commonly referred to as charge acceptance.

[0071] This conductive layer can also be applied to such as a sticker, retention pad, AGM separator, or rib or laminate structure in the gauntlet that is in close contact with the positive electrode. Since the positive active material on the plate is converted at different rates depending on the distance from the current collector source, some parts of the plate will quickly fully charge into gassing while other parts of the active material will remain charged and require more current. Thus, as gassing begins, a portion of the current can be wasted and result in higher positive grid corrosion rates. By providing an alternative path for the distribution of current to the positive grid, the current crowding is eliminated and the conversion will become more efficient resulting in less gas evolution and lower grid corrosion rates. These alternative paths for current distribution come from the conductive layer, such as a carbon structure, that is now on the separator rib, AGM separator, or laminate structure in direct contact with the positive electrode. The conductive material can easily be in contact with the positive paste (PAM) as the battery is formed, thus enhancing the conductive path and reducing or eliminating the interfacial barrier between the separator and the positive paste (positive plate).

[0072] Acid stratification—

[0073] To prevent acid stratification, the sulfuric acid boundary layer formed on the positive and negative plates during charging can be disrupted. Therefore, it is envisioned that a thin layer of porous silica will be deposited regardless of the material in contact with the plate surface (negative or positive). Since this silica layer is porous in itself and has a very high surface area, the acid will quickly diffuse, making it easy to mix with most of the acid. Since this silica layer can be in direct contact with the plate surface, it will also serve to mechanically interrupt the laminar flow of the acid boundary that relies mainly on gravity.

[0074] Therefore, it is envisioned that this silica layer can be deposited on the surface of the separator, or on the ribs, AGM, laminated structure in direct contact with the plates (such as pasting paper), retention mat or manifold, or any combination thereof.

[0075] The material, treatment or layer can be applied by a method of: vapor deposition, chemical deposition, vacuum assisted method, PVD, CVD, TD, DCD, PACVD, DLC, thin film coating or deposition technique, nanofilm technique, monoatomic thick coating technique, sol-gel, solvent coating, aqueous coating, etc., or any combination thereof. For example:

[0076] PVD: Physical Vapor Deposition - the use of a high energy beam to move atoms from a metal or alloy or composite target and deposit them on the surface of interest. The atoms escape the target surface as an ionized vapor. Various energy sources are possible such as electron beam, thermal energy, surface resistance heating, pulsed laser, plasma discharge, etc. All of these methods are vacuum assisted.

[0077] CVD: Chemical Vapor Deposition - reactive precursors containing the material to be deposited in some chemical form react or decompose on the substrate surface and form a deposit. Volatile byproducts of the precursor decomposition or reaction will be pumped out of the deposition chamber. The precursors are gaseous substances chemically designed to form a deposit of the appropriate chemical nature on the surface. The unwanted parts of the precursors leave the chamber. Depending on the chamber pressure, the CVD method is called atmospheric pressure (APCVD), low pressure (LPCVD) and ultra-high vacuum (UHVCVD). Plasma-enhanced (PACVD) uses a plasma to enhance the reaction of the precursors. Other variations suitable for the deposition needs are possible.

[0078] DCD: Dynamic Compound Deposition - the coating is formed by a low temperature process that forms a dry thin film on the surface. The deposition is based on the principle of in-situ mechanical activation and surface chemical transformation. This can be assisted by PVD or CVD or a combination thereof. Using this process it is possible to develop micro- and macro-structures on the surface. One can envision forming a rigid rib or a coating on the entire surface by this process.

[0079] Thermal or thermally reactive deposition (TD) is a high temperature deposition process used to produce high temperature stable materials such as oxides, carbides, etc.

[0080] DLC is diamond like carbon. Diamond like is an insulating or dielectric material.

[0081] Among the many properties required in a separator, some are bulk and others are surface properties. The present invention at least selected embodiments can address the surface related properties at the surface and in doing so can reduce the bulk requirements or costs. For example, oxidation resistance is required on the surface that is in contact with the positive plate, so we can reduce the oxidation resistance components in the bulk. Also, properties such as surface conductivity, oxidation resistance, acid stratification reduction, wettability improvement, etc. are surface required, so we can target these properties to the surface, for example, by coating.

[0082] Surface coating containing polar materials such as silica, alumina, etc. can provide the performance required in terms of acid stratification reduction, oxidation resistance improvement, wettability improvement, surface ionic conductivity improvement, etc. by any method such as chemical vapor deposition, atomic layer deposition (ALD), sol-gel coating, roll coating, etc. Precise thickness can be achieved to the desired or required level using these methods. High purity can also be accomplished by these methods.

[0083] Improved charge acceptance can be envisioned by having a combination of carbon or any other conductive or semiconductive layer or conductive layer and a polar layer (e.g. silica and carbon together).

[0084] The vapor deposition process is a vacuum or low pressure assisted process. The presence of oil in the separator can cause the coating to blister as the oil tends to ooze out of the pores in a vacuum. This problem is eliminated by the dry thin film coating with the layer of the present invention. Also, the adhesion of this layer to the substrate can not be a big issue as the separator also contains silica that helps to adhere the polar oxide coating to the substrate.

[0085] Advantages of at least some embodiments of the present invention:

[0086] 1. Providing the required functionality by a surface layer helps to separate the problem and solve the problem by a variety of methods.

[0087] 2. Improving the surface performance not only improves the performance of the separator but also improves the charge and discharge performance of the battery, charge acceptance ability, etc.

[0088] 3. Numerous coating methods and materials are possible. Even roll coating can be done with a small amount of binder to coat glass fibers, cellulose fibers, carbon fibers, conductive carbon fibers, etc. on the surface of the separator. This can be applied in the form of ribs by a screen printing method using a mask.

[0089] Non-limiting Examples

[0090] a. Both sides coated with the same material

[0091] The polymer substrate can be coated on both sides with a conductive carbon coating applied by roll coating. The desired coating thickness can be from about 1 μm to about 20 μm. This can improve the surface conductivity of the surface of the battery constructed with this separator, reduce current crowding, improve current distribution and increase charge acceptance. The carbon is porous and can also provide acid retention on both electrodes to reduce acid stratification.

[0092] b. Different coatings on each side, for example: aluminum oxide on the positive side and silicon stone on the negative side

[0093] Aluminum can be deposited on the separator by physical vapor deposition in the presence of oxygen. Due to the presence of the plasma and oxygen, the aluminum on the surface of the substrate becomes aluminum oxide and deposits on the surface. The thickness of the coating is preferably about 2 μm to about 10 μm. Alumina is highly polar, which will reduce the barrier to diffusion of ions at the positive interface between the electrode and the separator. Alumina is porous, which can reduce acid stratification. Alumina can also potentially lock up (bind) metal ions that are detrimental to lead acid battery performance, such as Sb, Cr, Ni, Mn, etc. Silicon stone on the negative side can be deposited by sol-gel method with silicon stone coagulated in a small amount of polymer binder, such as acrylic resin. Roll coating can also be used to obtain a uniform thin layer, preferably about 1 μm to about 20 μm or higher order of magnitude. The high surface area of the silicon stone and alumina can potentially prevent migration of detrimental ions, reduce acid stratification and increase the stiffness and puncture resistance of the thin film. Alumina provides oxidation resistance on the positive side. Thus, the polymer separator can have less oil, which is a sacrificial oxidation medium in polyethylene separators, which in turn can reduce the tendency to form black sludge, reduce cost, etc.

[0094] c. Two or more coatings

[0095] Three or more layers: carbon (spray) / alumina (reactive PVD) / silicon stone (sol-gel) / separator / carbon (spray), from the positive to the negative plate facing side. Similar methods as described above can be employed. It can be preferred to first coat the silicon stone on one side of the separator. Then alumina is deposited on top of the silicon stone. Then carbon is deposited on both sides. This results in both sides having surface conductivity and hydrophilicity from the alumina and silicon stone. The alumina and silicon stone provide oxidation resistance to the polymer separator.d. Gradient coating (high carbon content on the surface of the coating, high alumina content near the base film coating): carbon / alumina-carbon composite / separator

[0096] The separator can first be coated with alumina in oxygen using reactive physical vapor deposition to about 2 to about 4 microns. The target is changed to an Al-C composite target which when sputtered creates a different carbon loading in the alumina. This provides a low concentration of carbon concentration gradient close to the separator. The topmost carbon layer is deposited by CVD. By doing this, the concentration gradient of carbon reaches 100% carbon on the surface, about 50% carbon in the middle region to about 0% carbon close to the PE separator surface. By doing this, the ionic conductivity can be extended, higher porosity is achieved to trap contaminants such as Cr, Mn, etc., and the need for oil to reduce black staining is reduced.

[0097] e. Possible two layer coating: carbon on top of alumina on top of separator.

[0098] Carbon by CVD or roll coating. Advantages: surface conduction, oxidation resistance, reduce acid stratification, improve charge acceptance.

[0099] Alumina by reactive PVD: increase diffusion of ions through the separator. Reduce migration of harmful ions such as Cr, Sb, Mn, etc. from the positive electrode to the negative electrode.

[0100] f. Possible gradient coating

[0101] Carbon gradient is preferred because it provides electrical conductivity.

[0102] Alumina coating is also preferred because it has high oxidation resistance.

[0103] g. Possible positive plate side coating

[0104] Preferred positive side coating is a material that provides high oxidation resistance in deep cycle flooded lead acid batteries. Conductive carbon provides high surface conduction in starting, lighting, ignition (SLI) batteries, provides high cold cranking amps (CCA) and dynamic charge acceptance capability.

[0105] h. Possible negative plate side coating

[0106] The negative side of the separator is not oxidized. However, the presence of a porous coating on top reduces acid stratification. Carbon provides improved interfacial conduction on the negative side and can increase capacity.

[0107] i. Other possible preferred examples

[0108] Nafion coating (fluoropolymer copolymer based on sulfonated tetrafluoroethylene) or polytetrafluoroethylene (PTFE) that can be used in flow batteries can prevent diffusion of vanadium, chromium, iron, etc. This property can be very useful for lead acid batteries that can be plagued by antimony elements (positive grid made of Pb-Sb that provides deep cycle performance), chromium that can come from supplemental acid in dry cells, iron in silica stone used in PE separators, etc. These elements have electrochemical activity at the potential state of the lead acid battery and can cause separator oxidation (Cr, Fe) or increase hydrogen gas escape (Sb) due to hydrogen overvoltage reduction by antimony deposited on the negative plate. Nafion can prevent diffusion of these ionic species. A thin coating of about 2 to about 10 μιη thickness is believed to provide the required barrier properties for diffusion of these ions. If this material is stored on top of the AGM, it opens up new possibilities for using AGM type separators in antimony containing systems. Similar functionality can be expected from materials such as polyethylene oxide with sulfonic acid side chains or other complexing groups as side chains.

[0109] j. Cellulose separators or paper separators are commonly used in dry cells

[0110] This separator is generally made up of four basic components: cellulose fibers, phenol formaldehyde resin (novolac), wetting agent, and cellulose binder. The cellulose imparts oxidation resistance during formation and function of the battery. The PE separator of the present invention can be coated with a layer of about 1 to 20 μιη of a cellulose-binder mixture. The surface layer will impart the required oxidation resistance to the PE separator in Cr or other metal containing environments such as those found in dry cells.

[0111] k. Possible coating of the battery case, flat plate, glass mat, viewing device, and / or separator

[0112] A thin layer of glass fibers with a small amount of organic binder (less than about 1%) can be deposited on top of the PE separator by spraying or roll coating, etc. The entire assembly is cured to form a thin layer of glass fibers on top of the separator. Glass fibers have very high oxidation resistance and provide capillary forces to hold the acid and prevent acid stratification.

[0113] Microporous membrane

[0114] The separator of the present application preferably comprises a porous substrate or membrane (such as a microporous membrane having pores less than about 1 μm, mesoporous or macroporous membranes having pores greater than about 1 μm) made from natural or synthetic materials, for example, such as polyolefins, polyethylene, polypropylene, phenol formaldehyde resin, PVC, rubber, synthetic wood pulp (SWP), glass fiber, cellulose fiber or combinations thereof, more preferably a microporous membrane made from a thermoplastic polymer. Preferred microporous membranes can have a pore diameter of about 0.1 μm (100 nm) or less and a porosity of about 60%. In principle, the polymer can include all acid resistant thermoplastics suitable for use in lead acid batteries. Preferred thermoplastic polymers include polyethylene and polyolefins. The polyethylene based materials include, for example, polyvinyl chloride (PVC). The polyolefins include, for example, polyethylene, ultra-high molecular weight polyethylene (UHMWPE) and polypropylene. One preferred embodiment can include UHMWPE and a filler. Generally, preferred separators can be made by mixing UHMWPE and process oil in an extruder filler. In some embodiments, preferred separators can be prepared by mixing about 30 wt% of a filler with about 10 wt% of UHMWPE and about 60% of process oil in an extruder. In other embodiments, the filler content is higher, for example, about 50 wt%, 60 wt%, 70 wt% or 80 wt%. In other alternative embodiments, the process oil is no more than 60 wt%, 50 wt%, 45 wt%, 40 wt%, 35 wt%, 30 wt%, 25 wt%, 20 wt%, 15 wt% or 10 wt%. The mixture can also contain trace amounts of other additives or agents common in the art of separators (e.g., wetting agents, colorants, anti-static additives, etc.) and is extruded into sheet form.

[0115] The microporous separator layer is preferably made from a polyolefin such as polypropylene, ethylene-butene copolymer, polyethylene-polybutadiene copolymer, polyethylene-polyisoprene copolymer, preferably polyethylene, more preferably high molecular weight polyethylene, i.e., polyethylene having a molecular weight of at least 600,000, even more preferably ultra-high molecular weight polyethylene, i.e., polyethylene having a molecular weight of at least 1,000,000, particularly more than 4,000,000, and most preferably 5,000,000 to 8,000,000 (measured by viscosity measurement and calculated by Margolie equation), a standard load melt index of essentially zero (according to ASTM D 1238 (Condition E) using a standard load of 2,160 g), and a viscosity value of no less than 600 ml / g, preferably no less than 1000 ml / g, more preferably no less than 2,000 ml / g, and most preferably no less than 3,000 ml / g (determined in a 0.02 g polyolefin solution in 100 g of naphthalene at 130°C).

[0116] According to at least one embodiment, the separator is made of ultra-high molecular weight polyethylene (UHMWPE) mixed with processing oil and filler. According to at least one other embodiment, the separator is made of ultra-high molecular weight polyethylene (UHMWPE) mixed with processing oil, additives, and talc. The microporous polymer layer preferably comprises a uniform mixture of 8 to 100 volume percent polyolefin, 0-40 volume percent plasticizer, and 0 to 92 volume percent inert filler. The preferred filler is talc. The preferred plasticizer is petroleum oil. Since the plasticizer is the component most easily removed from the polymer-filler-plasticizer combination, it can be used to impart porosity to the battery separator.

[0117] In certain embodiments, residual processing oil can be removed after extrusion by conventional methods such as solvent washing, oven, etc. In certain selected embodiments, the final amount of processing oil present in the extruded polymer is no more than 20%, 18%, 16%, 14%, 12%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, or 0.5%.

[0118] In certain cases, the preferred filler is dry finely divided silica. However, the filler can be selected from the group consisting of silica, fumed silica, mica, montmorillonite, kaolinite, asbestos, talc, diatomaceous earth, vermiculite, natural and synthetic zeolites, cement, calcium silicate, clay, aluminum silicate, sodium aluminum silicate, polyaluminum silicate, alumina silica gel, glass particles, carbon black, activated carbon, carbon fibers, conductive carbon fibers, other conductive fibers, cellulose fibers, charcoal, graphite, titanium oxide, iron oxide, copper oxide, zinc oxide, lead oxide, tungsten, antimony oxide, zirconium oxide, magnesium oxide, aluminum oxide, molybdenum disulfide, zinc sulfide, barium sulfate, strontium sulfate, calcium carbonate, magnesium carbonate, and the like, and various combinations thereof. For example, thin layers of fumed silica can be coated with an organic solvent and potentially eliminate acid stratification and provide oxidation resistance. Thin layers of fumed silica can include carbon or other materials. For example, infiltrating fumed silica with cellulose fibers and a binder as a thin film on top of a PE membrane can secure the fumed silica in place. Also, a thin fumed silica layer can be applied on one side and a carbon layer can be applied on the other side, or a thin carbon layer can be applied on top of the fumed silica thin layer.

[0119] The porous membranes used in the various embodiments herein can be provided with one or more additives or agents. One such additive that can be present in the polyolefin is a surfactant. Suitable surfactants include surfactants such as alkyl sulfates; alkyl aryl sulfonates; alkyl phenol-alkylene oxide adducts; soaps; alkyl-naphthalene sulfonates; dialkyl esters of sulfosuccinic acid salts; quaternary amines; block copolymers of ethylene oxide and propylene oxide; and salts of mono- and di-alkyl phosphates. The additive can be a nonionic surfactant, for example, a polyol fatty acid ester, a polyethoxylated ester, a polyethoxylated fatty alcohol, an alkyl polysaccharide such as an alkyl polyglycoside and mixtures thereof, an amine ethoxylate, a sorbitan fatty acid ester ethoxylate, an organosilicone surfactant, an ethylene vinyl acetate terpolymer, an ethoxylated alkyl aryl phosphate, and a sucrose ester of a fatty acid.

[0120] In certain embodiments, the additive can be represented by a compound of formula (I)

[0121] R(OR 1 ) n (COOM x+ 1 / x ) m (I)

[0122] wherein

[0123] • R is a non-aromatic hydrocarbon group having 10 to 4200 carbon atoms, preferably 13 to 4200 carbon atoms, which can be interrupted by oxygen atoms,

[0124] • R 1 is H, -(CH2) k COOM x+ 1 / x or -(CH2) k -SO3M X+ 1 / X , preferably H, wherein k is 1 or 2,

[0125] • M is an alkali metal or alkaline earth metal ion, H + or NH4 + , wherein not all of the variables M simultaneously have the H + group,

[0126] • n is 0 or 1,

[0127] • m is 0 or an integer from 10 to 1400, and

[0128] • x is 1 or 2,

[0129] The ratio of oxygen atoms to carbon atoms in the compound of formula (I) is in the range from 1 : 1.5 to 1 : 30, m and n cannot simultaneously be 0. However, it is preferred that only one of the variables n and m is not equal to 0.

[0130] Non-aromatic hydrocarbon radicals mean radicals which do not contain aromatic groups or which represent one by themselves. The hydrocarbon radicals can be interrupted by oxygen atoms, i.e. contain one or more ether groups.

[0131] R is preferably a linear or branched aliphatic hydrocarbon radical which can be interrupted by oxygen atoms. Saturated, uncrosslinked hydrocarbon radicals are very particularly preferred.

[0132] The additives of the compounds of the formula (I) for the production of the various porous membranes described herein can also provide effective protection against oxidative destruction of such separators. In some embodiments, the porous membrane is preferred which comprises an additive containing a compound according to the formula (I), wherein

[0133] • R is a hydrocarbon radical having 10 to 180, preferably 12 to 75 and very particularly preferably 14 to 40 carbon atoms, which can be interrupted by 1 to 60, preferably 1 to 20 and very particularly preferably 1 to 8 oxygen atoms, particularly preferably a hydrocarbon radical of the formula R 2 - [(OC2H4) p (OC3H6) q ]- is to be understood as also including compounds in which the sequence of the radicals within the square brackets differs from those indicated. For example, compounds in which the radicals in the brackets form by exchanging the (OC2H4) and (OC3H6) radicals are suitable according to the application.

[0134] • R 2 is an alkyl radical having 10 to 30 carbon atoms, preferably 12 to 25, particularly preferably 14 to 20 carbon atoms,

[0135] • p is an integer from 0 to 30, preferably from 0 to 10, particularly preferably from 0 to 4, and

[0136] • q is an integer from 0 to 30, preferably from 0 to 10, particularly preferably from 0 to 4,

[0137] • particularly preferred compounds in which the sum of p and q is from 0 to 10, particularly from 0 to 4,

[0138] • n is 1, and

[0139] • m is 0.

[0140] The formula R 2 - [(OC2H4) p (OC3H6) q ]- is to be understood as also including compounds in which the sequence of the radicals within the square brackets differs from those indicated. For example, compounds in which the radicals in the brackets form by exchanging the (OC2H4) and (OC3H6) radicals are suitable according to the application.

[0141] in which R 2Additives which are linear or branched alkyl groups having 10 to 20, preferably 14 to 18, carbon atoms have proved to be particularly advantageous. OC2H4preferably stands for OCH2CH2, OC3H6for OCH(CH3)CH2and / or OCH2CH(CH3).

[0142] Particularly preferred alcohols (p = q = 0; m = 0) are primary alcohols, preferably primary alcohols of fatty alcohol ethoxylates (p = 1 to 4; q = 0), fatty alcohol propoxylates (p = 0; q = 1 to 4) and fatty alcohol alkoxylates (p = 1 to 2; q = 1 to 4). Fatty alcohol alkoxylates can be obtained, for example, by reaction of the corresponding alcohol with ethylene oxide or propylene oxide.

[0143] Additives which are insoluble or poorly soluble in water and sulfuric acid of the type m = 0 have proved to be particularly advantageous.

[0144] Preference is also given to additives which contain compounds according to formula (I), wherein

[0145] • R is an alkane radical having 20 to 4200, preferably 50 to 750 and very particularly preferably 80 to 225, carbon atoms,

[0146] • M is an alkali metal or alkaline earth metal ion, H + or NH 4+ , in particular an alkali metal ion such as Li + , Na + and K + or H + , wherein not all of the variables M simultaneously have H + groups,

[0147] • n is 0,

[0148] • m is an integer from 10 to 1400

[0149] • x is 1 or 2.

[0150] Particularly suitable as additives here are polyacrylic acid, polymethacrylic acid and acrylic-methacrylic acid copolymers in which the acid groups are at least partially, preferably 40%, and particularly preferably 80%, neutralized. The percentages refer to the number of acid groups. Very particularly preferred are poly(meth)acrylic acids which are completely present in salt form. By poly(meth)acrylic acid is meant polyacrylic acid, polymethacrylic acid and acrylic-methacrylic acid copolymers. Preferred are poly(meth)acrylic acids, in particular polyacrylic acids, having an average molar mass Mw of from 1,000 to 100,000 g / mol, particularly preferably from 1,000 to 15,000 g / mol and very particularly preferably from 1,000 to 4,000 g / mol. The molecular weight of the poly(meth)acrylic acid polymers and copolymers is determined by measuring the viscosity of a 1 % aqueous solution of the polymer neutralized with sodium hydroxide solution (Fikentscher constant).

[0151] Copolymers of (meth)acrylic acid are also suitable, particularly suitable copolymers being copolymers which, in addition to (meth)acrylic acid, comprise as comonomers ethylene, maleic acid, methyl acrylate, ethyl acrylate, butyl acrylate and / or ethylhexyl acrylate. Preferred are copolymers which contain at least 40% by weight, preferably at least 80% by weight, of (meth)acrylic acid monomers, the percentages being based on the acid form of the monomers or polymers.

[0152] For neutralizing the polyacrylic acid polymers and copolymers, alkali and alkaline earth metal hydroxides such as potassium hydroxide, and in particular sodium hydroxide, are particularly suitable.

[0153] The porous membrane can be provided with one or more additives in various ways. For example, the additives can be applied to the polyolefin when the additives are finished (i.e. after extraction) or added to the coating mixture used to produce the porous membrane (e.g. during polymerization). According to one possible preferred embodiment, the additives or a solution of the additives can be applied to the surface of the porous membrane or the surface of the coating. This variant is particularly suitable, but not limited to, the use of non-thermally stable additives and additives which are soluble in the solvent used for subsequent extraction. The coating does not need to be extracted after coating. For example, after a PE separator has been formed by an extrusion extraction process, the material and additive coating mixture can be coated as a film on the PE membrane, after which no extraction is carried out, and if the additive coating precedes one or more electrically conductive or antioxidant, stiffness-enhancing coatings, the additive, being a polar material, can increase the adhesion between the PE substrate and the top coating.

[0154] Solvents that are particularly suitable as the additive of the present application are low molecular weight alcohols, such as methanol and ethanol, and mixtures of these alcohols with water. Application can occur on the side of the porous membrane facing the negative electrode, the side facing the positive electrode, or both sides. For embodiments in which the coating is present on only one side of the porous membrane, the additive can be applied to the coating, to the side of the coating that is not coated, or to both sides of the separator.

[0155] The additive can be present at a density of at least 0.5 g / m 2 1.0 g / m 2 1.5 g / m 2 2.0 g / m 2 2.5 g / m 2 3.0 g / m 2 3.5 g / m 2 4.0 g / m 2 4.5 g / m 2 5.0 g / m 2 5.5 g / m 2 6.0 g / m 2 6.5 g / m 2 7.0 g / m 2 7.5 g / m 2 8.0 g / m 2 8.5 g / m 2 9.0 g / m 2 9.5 g / m 2 or 10.0 g / m 2 . The additive can be present at a density of 0.5-10 g / m 2 1.0-10.0 g / m 2 1.5-10.0 g / m 2 2.0-10.0 g / m 2 2.5-10.0 g / m 2 3.0-10.0 g / m 2 3.5-10.0 g / m 2 4.0-10.0 g / m 2 4.5-10.0 g / m 2 5.0-10.0 g / m 2 5.5-10.0 g / m 2 6.0-10.0 g / m 2 6.5-10.0 g / m 2 7.0-10.0 g / m 2 7.5-10.0 g / m 2 5.0-10.5 g / m 2 5.0-11.0 g / m 2, 5.0-12.0 g / m 2 or 5.0-15.0 g / m 2 A density range of 5.0-12.0 g / m

[0156] Application can also be performed by immersing the polyolefin layer in an additive or additive solution and subsequently selectively removing the solvent, for example by drying. In this way, the application of the additive can be combined with extraction, for example as is commonly used in the production of the microporous polyolefin separator layer.

[0157] The thickness of the porous membrane is preferably greater than 0.1 mm and less than or equal to 5.0 mm. The thickness of the porous membrane can be in the range of 0.15-2.5 mm, 0.25-2.25 mm, 0.5-2.0 mm, or 0.75-1.5 mm. The porous membrane can be about 0.8 mm or 1.1 mm thick.

[0158] In certain selected embodiments, the back web thickness of the porous membrane is no greater than 500 μm, 400 μm, 300 μm, 250 μm, 200 μm, 175 μm, 150 μm, 125 μm, 100 μm, or less. In various embodiments, the porous membrane comprises ribs. Preferred ribs can be 0.008 mm to 1 mm high and can be spaced 0.001 mm to 10 mm apart. For example, the ribs can be spaced 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2.0 mm,

[0159] 2.25 mm, 2.5 mm, 2.75 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm apart. In some embodiments, the ribs can be in various forms, for example, they can be on one side of the separator layer or on both sides of the porous membrane, from 0 degrees to 90 degrees relative to each other. In certain selected embodiments, the ribs are at an angle of 0, 45, or 90 degrees to each other on both sides of the porous membrane. Various forms including ribs on both sides of the separator layer can include negative cross ribs on the second or back side of the separator.

[0160] According to at least another object of the present invention, a ribbed porous membrane is provided. The ribbed porous membrane can have cross ribs on opposite faces of the porous membrane as well as longitudinal ribs. In some embodiments of the present invention, the ribbed porous membrane can have ribs of at least 0.005 mm, 0.01 mm, 0.025 mm, 0.05 mm, 0.075 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm,

[0161] 0.9 mm or 1.0 mm. The ribbed porous membrane can have a transverse rib height of between 0.005-1.0 mm, 0.01-0.5 mm, 0.025-0.5 mm, 0.05-0.5 mm, 0.075-0.5 mm, 0.1-0.5 mm, 0.2-0.4 mm, 0.3-0.5 mm, or 0.4-0.5 mm.

[0162] In some embodiments of the application, the ribbed porous membrane can have a longitudinal rib height of at least 0.005 mm, 0.01 mm, 0.025 mm, 0.05 mm, 0.075 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, or 1.5 mm. The ribbed porous membrane can have a transverse rib height of between 0.005-1.5 mm, 0.01-1.0 mm, 0.025-1.0 mm, 0.05-1.0 mm, 0.075-1.0 mm, 0.1-1.0 mm, 0.2-1.0 mm, 0.3-1.0 mm, 0.4-1.0 mm, 0.5-1.0 mm, 0.4-0.8 mm, or 0.4-0.6 mm.

[0163] In some embodiments of the application, the ribbed porous membrane can have a sheet (substrate) thickness of at least 0.005 mm, 0.01 mm, 0.025 mm, 0.05 mm, 0.075 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1.0 mm. The ribbed porous membrane can have a sheet (substrate) thickness of between 0.005-1.0 mm, 0.01-1.0 mm, 0.025-1.0 mm, 0.05-1.0 mm, 0.075-1.0 mm,

[0164] 0.1-1.0 mm, 0.2-1.0 mm, 0.3-1.0 mm, 0.4-1.0 mm, 0.4-1.0 mm, 0.4-0.9 mm, 0.4-0.8 mm, 0.5-0.8 mm, or 0.6-0.8 mm.

[0165] In some embodiments of the application, the ribbed porous membrane can have a total thickness (positive rib + back web + negative rib) of at least 0.05 mm, 0.1 mm, 0.25 mm, 0.5 mm, 0.75 mm, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm, 5.0 mm, or 6.0 mm. The ribbed porous membrane can have a transverse rib height of between 0.05-5.0 mm, 0.1-5.0 mm, 0.2-5.0 mm, 0.5-5.0 mm, 1.0-5.0 mm, or 1.0-4.0 mm.

[0166] In some cases, the ribs do not necessarily occur on one or both sides. For example, the separator, substrate, or membrane can be a flat sheet or have ribs on only one side.

[0167] With respect to at least selected embodiments of the application, the ribbed porous membrane can have the following characteristics:

[0168] 1) Transverse rib height - preferably between about 0.02 to 0.45 mm, and most preferably between about 0.075 to 0.3 mm.

[0169] 2) Sheet (substrate) thickness - preferably between about 0.065 to 0.75 mm.

[0170] 3) Total thickness (positive rib + back web + negative rib) - separator thickness between about 0.10 to 6.0 mm, preferably between about 0.20 to 4.0 mm.

[0171] The ribs can be jagged. The jagged teeth can have an average tip length of 0.05 mm to 1 mm. For example, the average tip length can be greater than or equal to 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm; and / or less than or equal to 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm.

[0172] The jagged teeth can have an average base length of 0.05 mm to 1 mm. For example, the average base length can be greater than or equal to 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm; and / or less than or equal to 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm.

[0173] 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm; and / or less than or equal to 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm.

[0174] 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm.

[0175] The average height of the sawteeth can be from 0.05 mm to 1 mm. For example, the average height can be greater than or equal to 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm; and / or less than or equal to 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm. For embodiments in which the sawteeth have the same height as the ribs, the sawteeth ribs can also be referred to as protrusions.

[0176] The average center-to-center distance of the sawteeth can be from 0.1 mm to 50 mm. For example, the average center-to-center distance can be greater than or equal to 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.25 mm, or 1.5 mm; and / or less than or equal to 1.5 mm, 1.25 mm, 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, or 0.2 mm.

[0177] The sawteeth can have an average height-to-base width ratio of 0.1 : 1 to 500: 1. For example, the average height-to-base width ratio can be greater than or equal to 0.1 : 1, 25: 1, 50: 1, 100: 1, 150: 1, 200: 1, 250: 1, 300: 1, 350: 1, or 450: 1; and / or less than or equal to 500: 1, 450: 1, 400: 1, 350: 1, 300: 1, 250: 1, 200: 1, 150: 1, 100: 1, 50: 1, or 25: 1.

[0178] The serrations can have an average base width to tip width ratio from 1000: 1 to 0.1 : 1. For example, the average base width to tip width ratio can be greater than or equal to 0.1 : 1, 1 : 1, 2: 1, 3: 1, 4: 1, 5: 1, 6: 1, 7: 1, 8: 1, 9: 1, 10: 1, 15: 1, 20: 1, 25: 1, 50: 1, 100: 1, 150: 1, 200: 1, 250: 1, 300: 1, 350: 1: 450: 1, 500: 1, 550: 1, 600: 1, 650: 1, 700: 1, 750: 1, 800: 1, 850: 1, 900: 1, 950: 1, and / or less than or equal to 1000: 1, 950: 1, 900: 1, 850: 1, 800: 1, 750: 1, 700: 1, 650: 1, 600: 1, 550: 1, 500: 1, 450: 1: 400: 1, 350: 1, 300: 1, 250: 1, 200: 1, 150: 1, 100: 1, 50: 1, 25: 1, 20: 1, 15: 1, 10: 1, 9: 1, 8: 1, 7: 1, 6: 1, 5: 1, 4: 1, 3: 1, 2: 1, or 1 : 1.

[0179] In some embodiments, the porous membrane can be perforated. The perforations can be one row or one line of substantially identical sized holes. The row or line can be spaced 0.001 mm to 10 mm apart. For example, the row can be spaced 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2.0 mm, 2.25 mm, 2.5 mm, 2.75 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm apart.

[0180] The perforations can have an average hole length from 0.05 mm to 1 mm. For example, the average tip width can be greater than or equal to 0.05 mm,

[0181] 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm; and / or less than or equal to 1.0 mm,

[0182] 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm.

[0183] The average hole width of the perforations can be from 0.01 mm to 1 mm. For example, the average hole width can be greater than or equal to 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm; and / or less than or equal to 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm.

[0184] The perforations can have an average center-to-center pitch of 0.1 mm to 50 mm. For example, the average center-to-center pitch can be greater than or equal to 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.25 mm, or 1.5 mm; and / or less than or equal to 1.5 mm, 1.25 mm, 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, or 0.2 mm.

[0185] The perforations can be quadrilateral, such as square and rectangular. The perforations can have an average hole length / hole width ratio of 0.1:1 to 1000:1. For example, the average length to width ratio can be greater than or equal to 0.1:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 15:1, 20:1, 25:1, 50:1, 100:1, 150:1, 200:1, 250:1, 300:1, 350:1, 450:1, 500:1, 550:1, 600:1, 650:1, 700:1, 750:1, 800:1, 850:1, 900:1, 950:1, and / or less than or equal to 1000:1, 950:1, 900:1, 850:1, 800:1, 750:1, 700:1, 650:1, 600:1, 550:1, 500:1, 450:1, 400:1, 350:1, 300:1, 250:1, 200:1, 150:1, 100:1, 50:1, 25:1, 20:1, 15:1, 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, or 1:1.

[0186] In some embodiments, the holes can be triangular. Typically, the triangular holes are equilateral triangles with a side length of 0.01 mm to 1 mm. For example, the average triangular side length can be greater than or equal to 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm; and / or less than or equal to 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm,

[0187] 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm.

[0188] In some embodiments, the holes can be approximately circular. The diameter of the circular holes can be from about 0.05 to 1.0 mm. For example, the average hole diameter can be greater than or equal to 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm; and / or less than or equal to 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm.

[0189] In some embodiments, the porous membrane can be dimpled. The dimples are arranged on the porous membrane in a manner similar to perforations, however, dimples are indentations in the surface of the porous membrane, rather than complete voids. The thickness of the dimples can be 1-99% of the thickness of the porous membrane. For example, the average thickness of the dimples can be less than 95%, 90%, 85%, 80%, 75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30%, 25%, 20%, 15%, 10%, or 5%. The dimples can be arranged in rows along the porous membrane. The rows or lines can be spaced 0.001 mm to 10 mm apart. For example, the rows can be spaced 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2.0 mm, 2.25 mm, 2.5 mm,

[0190] 2.75 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm apart.

[0191] The dimples can have an average dimple length of 0.05 mm to 1 mm. For example, the average dimple length can be greater than or equal to 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm; and / or less than or equal to 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm.

[0192] The dimples can have an average dimple length of 0.05 mm to 1 mm. For example, the average dimple length can be greater than or equal to 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm; and / or less than or equal to 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm.

[0193] The dimples can have an average dimple length of 0.05 mm to 1 mm. For example, the average dimple length can be greater than or equal to 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm; and / or less than or equal to 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm.

[0194] The dimples can have a shape that is a quadrilateral, such as a square and a rectangle. The dimples can have an average dimple length to dimple width ratio of 0.1 : 1 to 100: 1. For example, the average length to base width ratio can be greater than or equal to 0.1 : 1, 1 : 1, 2: 1, 3: 1, 4: 1, 5: 1, 6: 1, 7: 1,

[0195] 8:1, 9:1, 10:1, 15:1, 20:1, 25:1, 50:1, 100:1, 150:1, 200:1, 250:1, 300:1, 350:1, 450:1, 500:1, 550:1, 600:1, 650:1, 700:1, 750:1, 800:1, 850:1, 900:1, 950:1, and / or less than or equal to 1000:1, 950:1, 900:1, 850:1, 800:1, 750:1, 700:1, 650:1, 600:1, 550:1, 500:1, 450:1, 400:1, 350:1, 300:1, 250:1, 200:1, 150:1, 100:1, 50:1, 25:1, 20:1, 15:1, 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, or 1:1.

[0196] In some embodiments, the dimples can be substantially circular. The circular dimples can have a diameter of about 0.05 to 1.0 mm. For example, the average dimple diameter can be greater than or equal to 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm; and / or less than or equal to 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm,

[0197] 0.3 mm, 0.2 mm, or 0.1 mm.

[0198] In some embodiments, the porous membrane can have a combination of serrations, holes, slits, and / or dimples. For example, the porous membrane can have a first series of serrated ribs extending along the separator from top to bottom, and a second series of serrated ribs extending horizontally along the separator. In other embodiments, the porous membrane can have an alternating sequence of serrated ribs, dimples, and / or perforations. Additionally, the pouch, sleeve, or wrapped separator can have openings or slits to allow movement of the acid.

[0199] According to at least one embodiment, the porous membrane is made from ultra-high molecular weight polyethylene (UHMWPE) mixed with processing oil, additives, and deposited silica. According to at least one other embodiment, the porous membrane is made from ultra-high molecular weight polyethylene (UHMWPE) mixed with processing oil and deposited silica. The processing oil can be selectively removed as described above. The additives can then be applied to the porous membrane by one or more of the techniques described above. According to at least one particular embodiment, the negative cross ribs are circular mini-ribs and preferably have a radius of 2 to 6 mils and a rib spacing of 10 to 50 mils.

[0200] According to at least selected embodiments, the porous membrane comprises a porous membrane having a backweb and optionally one or more positive ribs and / or negative ribs thereon. For example, the porous membrane can comprise a porous membrane having a backweb and at least two positive ribs on the positive side of the backweb and optionally a plurality of smaller negative cross ribs or cross ribs on the negative side of the backweb. The positive ribs can be straight or wavy, can have solid portions, can have truncated pyramid shapes, can be jagged, battlements, discontinuous, continuous, nubs, protrusions or combinations thereof. The negative ribs can be smaller than the positive ribs and can be straight or wavy, can have solid portions, can have truncated pyramid shapes, can be jagged, battlements, discontinuous, nubs, protrusions, micro-ribs, transverse, longitudinal or combinations thereof. Also, the positive and negative face ribs can have the same dimensions (same dimensions on both sides) and can be parallel, angled or perpendicular to each other. For example, both sides can have small ribs or micro-ribs and such ribs can be parallel, angled or perpendicular to each other. The membrane can be selected from polyolefins, rubbers, polyvinyl chloride, phenolic, cellulose or combinations thereof and the membrane is preferably a polyolefin (PO) material, more preferably polyethylene (PE), forming a porous or microporous membrane for battery cell separators.

[0201] In at least one embodiment, the porous membrane is made of a microporous thermoplastic material having longitudinal positive ribs and transverse negative ribs, wherein at least a majority of the longitudinal ribs have a height greater than the height of the transverse ribs, and the longitudinal and transverse ribs are solid ribs integrally formed from the plastic, characterized in that the transverse ribs extend across substantially the entire back width of the separator. The porous membrane backweb or sheet can have a thickness of about 0.10 to 0.50 mm, the longitudinal ribs can have a height of 0.3 to 2.0 mm, and the transverse ribs can have a height of 0.1 to 0.7 mm, a longitudinal stiffness of about 5 mJ for a 100 mm width, a transverse stiffness of about 2.5 mJ, and a total thickness of the porous membrane of less than 3.5 mm, preferably less than 2.5 mm.

[0202] Coating material

[0203] The exemplary coating materials described herein can impart improved oxidation resistance, improved wettability, reduced black staining, improved surface conductivity, increased stiffness, and / or improved resistance to oxidation induced by metal contamination, for example, to the porous membranes described above. The coating materials can improve the charge acceptance and / or reduce acid stratification of a battery, particularly a lead acid battery. In some embodiments, the coating material is hydrophilic, porous, conductive, oxidation resistant, or self-adhering to the porous membrane. In some selected embodiments, the coating material is hydrophilic and porous, or hydrophilic, porous, and oxidation resistant, or hydrophilic, porous, and conductive, or hydrophilic, porous, oxidation resistant, and conductive, or any combination thereof.

[0204] Exemplary coating materials include, but are not limited to, silica, fumed silica, silicon oxide, alumina, aluminum oxide, metals, metal oxides, cellulose, carbon, and conductive carbon materials. In certain embodiments, the coating material is a single type of material, while in other embodiments, the coating material comprises two or more of the above materials, such as silica and silicon oxide, alumina and aluminum oxide, silica and carbon, and the like.

[0205] Exemplary metal oxides that can be present in the coating include aluminum oxide (AI2O3), boehmite γ- AI O(OH), silicon oxide, and oxides of transition metals, and the like, or mixtures thereof.

[0206] Exemplary conductive carbons include graphite, graphene, graphene oxide, carbon nanotubes, carbon fibers, and the like.

[0207] In certain selected embodiments, the coating can contain one of the above materials in combination with a polymer, binder, or carrier material. Exemplary carrier materials include glass mats, ceramics, and polymers. Exemplary polymers include polyolefins, PVDF, PVDF:HFP, PEO, PTFE, SBR, PVA, acrylics, and / or the like. In certain embodiments, the carrier mixture is uniformly mixed with the aforementioned materials, and in other embodiments, the materials are present in the form of granular agglomerates.

[0208] The coating can be present on the face of the porous membrane facing the positive electrode, the face of the porous membrane facing the negative electrode, or both faces of the porous membrane. In certain embodiments, the face of the porous membrane facing the positive electrode can be coated with one material, while the face of the porous membrane facing the negative electrode can be coated with a different material. In other embodiments, both faces are coated or clad with the same material.

[0209] The one or more coatings can be present on either side of the porous membrane, in a thickness ranging from 0.1 pm to 250 pm, possibly preferably from 1 to 250 pm, 1 to 150 pm, 2.5 to 150 pm, 2.5 to 125 pm, 2.5 to 100 pm, 2.5 to 75 pm, 5 to 75 pm, 5 to 100 pm, 10 to 100 pm, 5 to 50 pm, 5 to 25 pm, 25 to 100 pm, 25 to 50 pm, 25 to 75 microns. In other embodiments, the coating can be applied in very thin thicknesses, for example less than 5 pm, 4 pm, 3 pm, 2 pm, 1 pm, 0.5 pm, or 0.25 pm. In other embodiments, the coating can be applied in thicker rates, for example greater than 5 pm, 10 pm, 15 pm, 20 pm, 25 pm, 30 pm, 35 pm, 40 pm, 50 pm, 75 pm, 100 pm, or 150 pm.

[0210] Coated porous membranes

[0211] The coated porous membranes described herein are preferably characterized by enhanced stiffness, oxidation resistance, wettability, and / or surface conductivity, resistance to oxidation caused by contamination, reduced black staining, and the like.

[0212] Methods of coating separators

[0213] In certain embodiments, the coating covers the entire porous membrane, while in other embodiments, the coating covers a portion of the porous membrane, for example on the ribs, on the back web, on the positive face, on the negative face, and / or stripes, color bands, other forms, and / or the like. The substrate or membrane can be a flat PE membrane, a ribbed PE membrane, an AGM, or other substrate. When the coating is applied as a rib or stripe or other form, the preferred substrate or membrane can be substantially flat. The coating layer can be applied to the porous membrane (or just the ribs) by dipping, doctor blade, curtain coating, gravure printing, solvent coating, aqueous coating, physical vapor deposition methods, atomic layer deposition methods, or chemical vapor deposition methods. Physical vapor deposition (PVD) can include various vapor deposition methods and / or vacuum deposition methods for depositing thin films by condensing a vaporized form of a desired film material onto various substrate surfaces. PVD is used to manufacture a variety of articles, including, by way of example only, semiconductor devices, aluminized PET film for balloons and food packaging bags, and coated cutting tools for metalworking. Vacuum metallization is a form of physical vapor deposition, a process of bonding metals to non-metallic substrates by evaporation. The most commonly used metal for vacuum metallization is aluminum, for a variety of reasons, such as cost, thermodynamics, and reflective properties.

[0214] In certain embodiments, a very thin coating is provided on the porous membrane. Such embodiments can be desirable because it occupies a smaller volume in the battery and can allow the battery to have a higher volumetric and gravimetric energy density.

[0215] In forming the coatings described herein, vapor deposition techniques can be employed to deposit a very thin coating in an ultra-thin thickness of less than 1 μιη. Physical vapor deposition (PVD), chemical vapor deposition (CVD), and atomic layer deposition (ALD) are three well-known types of vapor deposition techniques. Non-limiting examples of physical vapor deposition are sputtering and evaporation. Physical vapor deposition can include evaporating a metallic element, a reactive metallic element, an inert metallic element, or a metal oxide, and forming a layer on a substrate such as a porous membrane. The vapor-deposited layer can be deposited onto the porous membrane, the vapor-deposited layer consisting of individual atoms or molecules of a single layer of highly oxidation resistant material such as a metal and / or metal oxide. Further, the vapor-deposited layer can be deposited onto the porous membrane, the vapor-deposited layer consisting of individual atoms or molecules of multiple layers of highly oxidation resistant material such as an inert metallic element, a reactive metallic element, or a metal oxide compound. Additionally, the vapor-deposited layer can be deposited in a thickness of less than 1 μιη, more preferably in a thickness of less than about 0.5 μιη, more preferably less than about 0.1 μιη, and most preferably less than about 0.01 μιη. Most preferably, less than about a possible combination of one or more layers applied in various orders of metals and / or metal oxides is formed on the microporous membrane.

[0216] Atomic layer deposition (ALD), which is a thin film growth method in which deposits are deposited in layers, can also be used to apply the coating in a controlled manner. Typically, a vapor of a film precursor is absorbed on a substrate in a vacuum chamber. The vapor is then pumped out of the chamber, leaving a thin layer of absorbed precursor, typically substantially a single layer, on the substrate. A reactant is then introduced into the chamber under thermal conditions, which promotes a reaction with the absorbed precursor to form a layer of the desired material. The reaction product is pumped out of the chamber. Subsequent layers of material can be formed by again exposing the substrate to the precursor vapor and repeating the deposition process. ALD can produce very thin nanoscale films with extremely high density of layer production and minimal amount of defects.

[0217] Chemical vapor deposition (CVD) techniques can also be used to coat the coating in a controlled manner. Chemical vapor deposition is another widely used material processing technique that applies solid thin films to surfaces. It is used to deposit a wide variety of materials. In its simplest incarnation, CVD involves flowing one or more precursor gases into a chamber containing one or more heated objects onto which the CVD layers are to be applied. Chemical reactions occur on and near the hot surface, resulting in the deposition of a thin film on the surface. Accompanying chemical byproducts are exhausted out of the chamber along with unreacted precursor gases. It can be performed in hot-wall reactors and cold-wall reactors, at sub-torr total pressures to above atmospheric pressure, with and without carrier gases, and temperatures typically between 200-1600 °C. There are also various enhanced CVD processes that involve the use of plasma, ions, photons, lasers, hot filaments, or combustion reactions to increase the deposition rate and / or lower the deposition temperature.

[0218] The application of one or more deposition layers using PVD, CVD, or ALD can provide a reliable method to control the additional thickness of the deposited coating material. In certain selected embodiments, the thickness of the one or more deposition layers can be ultra-thin and in the range of less than about 5 pm, more preferably less than about 1 pm, more preferably less than about 0.5 pm, and most preferably less than about 0.1 pm. The application of one or more deposition layers using PVD, CVD, or ALD can provide a reliable method to control the additional thickness of the deposited coating material. In certain selected embodiments, the thickness of the one or more deposition layers can be ultra-thin and in the range of less than about 5 pm, more preferably less than about 1 pm, more preferably less than about 0.5 pm, and most preferably less than about 0.1 pm. The application of one or more deposition layers using PVD, CVD, or ALD can provide a reliable method to control the additional thickness of the deposited coating material. In certain selected embodiments, the thickness of the one or more deposition layers can be ultra-thin and in the range of less than about 5 pm, more preferably less than about 1 pm, more preferably less than about 0.5 pm, and most preferably less than about 0.1 pm.

[0219] These layers or coatings can be applied as a coating slurry or mixture or layer to one or both sides of the microporous battery separator to, among other things, facilitate high temperature stability in the battery, reduce acid stratification, improve wettability, improve stiffness, reduce thermal shrinkage, control oxidation at the separator-cathode interface of the battery, and improve the safety performance of the microporous battery separator, etc. Such coatings can be applied using known techniques such as, but not limited to, dip coating, doctor blade, gravure printing, curtain coating, etc., and can be applied in a thickness of about 2 pm to 6 pm, 5 pm to 75 pm, etc., or more on one or both sides of the microporous battery separator.

[0220] According to certain embodiments, a polymer coating containing polymer and / or ceramic particles can be applied on top of or with the metal and / or metal oxide deposition layer in order to further improve various properties of the separator, such as thermal stability of the separator at high temperatures.

[0221] According to certain embodiments, the battery separator described herein relates to a polymeric microporous membrane having a deposited layer comprising a highly oxidation resistant material (e.g., an inert metal element) applied thereon, wherein the deposited layer thickness is in the range of about about 1 pm. Non-limiting examples of inert metal elements can be gold and platinum. Depositing a chemically stable metal, such as gold or platinum, onto a microporous polymer membrane or film can create an oxidation resistant layer when the side of the microporous polymer membrane with the deposited layer is in contact with a cathode. When the battery is a high voltage battery, oxidation can be more aggressive, requiring a protective oxidation resistant layer to limit the oxidative degradation of the microporous polymer membrane to the cathode. The metal deposited layer according to various embodiments herein is an electrically conductive layer and can dissipate the current distribution within the battery cell. In at least certain embodiments, the inventive metal conductive deposited layer described herein can be applied to one or more non-conductive layers of polymer layers, such as polyolefins, such as but not limited to polypropylene, polypropylene blends, polypropylene copolymers or mixtures thereof and polyethylene, polyethylene blends, polyethylene copolymers or mixtures thereof. Non-limiting examples of non-conductive layers can include single, double, triple or multi-layer (co-extruded or laminated) porous membranes made by dry or wet processes, with added glass mat or other woven or non-woven layers, which are well known to those skilled in the art.

[0222] According to at least certain embodiments, examples of reactive metal elements can include the electrically conductive metal aluminum (Al). As an example of an active metal element, aluminum will form a super thin protective layer of aluminum oxide (AI2O3) when exposed to oxygen in the air. One layer of AI2O3 can be stable to further oxidation in air.

[0223] Various non-limiting examples can provide different sets of properties or improvements, which can include one or any combination of the following:

[0224] 1. One exemplary embodiment of conductivity enhancement can provide carbon, which can be deposited on one or both sides of the separator by various methods described herein, or in other methods known in the art.

[0225] 2. Another exemplary embodiment can provide oxidation resistance by depositing aluminum oxide, silicon dioxide, etc. on the positive side of the separator by various methods as described herein or known in the art.

[0226] 3. Another exemplary embodiment can provide a reduction in black staining by using less oil on one or both sides of the separator.

[0227] 4. Yet another exemplary embodiment can provide stiffness to the separator by depositing aluminum oxide, silicon dioxide, etc. on one or both sides of the separator by various methods described herein or other methods known in the art.

[0228] 5. Another exemplary embodiment can address acid stratification by incorporating silica, fibers, glass fibers, cellulose fibers, etc. deposited by various methods, and combinations of the materials described herein on the positive side of the separator.

[0229] 6. Another exemplary embodiment can include incorporating a cellulose coating that will provide resistance to oxidation caused by metal contaminants such as Cr, Mn, etc.

[0230] 7. Further, another exemplary embodiment can incorporate various geometries, such as by coating individual replacement ribs, covering glass fibers, glass fibers, cellulose fibers, or mixtures of fibers and silica as a coating, etc.

[0231] 8. Still further, Figures 2 to 4 the exemplary embodiments provided in any of

[0232] 9. Still further, Figure 5A and Figure 5B the exemplary embodiments provided in any of

[0233] 10. Still further, Figure 7 and 7A the exemplary embodiments provided in

[0234] 11. Pyrolytic silica mixed with binder by roll coating on the positive side and carbon by PVD on the negative side.

[0235] 12. Cellulose film with phenolic binder on the positive side and carbon on the negative side.

[0236] The range of stiffness of the separator can be measured by resistance to bending, for example by industry standard tests or as specified in BST E: 2530. The range of oxidation stability can be measured by: 1) weight loss occurring in hot sulfuric acid containing peroxodisulfate (hydrogen peroxide); or 2) Perox-80 test; or 3) by industry standard tests or specifications in BST E-2100, 2100-3, and BST E-2520. The range of wettability is measured in minutes (typically 3 and 10 minutes) and can be measured by submerging the separator horizontally and measuring wettability versus time, for example by industry standard tests or as specified in BST E: 2540 and 2543. The range of surface conductivity can be measured by electrochemical impedance spectroscopy.

[0237] According to at least selected embodiments, the present application or invention relates to new or improved porous membranes or substrates, separators, separators, composites, electrochemical devices, batteries, methods of making such membranes or substrates, separators, and / or batteries, and / or methods of using such membranes or substrates, separators, and / or batteries. According to at least certain embodiments, the present application relates to new or improved microporous membranes, battery separators, separators, energy storage devices including such separators, batteries, methods of making such membranes, separators, and / or batteries, and / or methods of using such membranes, separators, and / or batteries. According to at least certain selected embodiments, the present invention relates to separators for batteries having one or more oxidative protective deposition layers. The deposition layers are preferably thin or ultra-thin conductive or insulating deposition layers applied to a polymeric microporous membrane. The methods can use adhesives that are removed upon post-processing or solvents, such as water, that are removed in post-processes (such as heating / curing / annealing, etc.). In addition, the methods can use adhesives that are not removed (the adhesives can remain or stay) and hold the fibers or particles in the wet coating. Another method includes an adhesive-free and solvent-free deposition method. By employing the deposition layers, the energy density of the battery can be increased. In addition, the deposition methods can preferably deposit uniform layers that are less than about 0.5 pm. According to at least particular embodiments, the battery separators described herein relate to multi-layer or composite microporous membrane battery separators that can have superior oxidation resistance and can be stable in high voltage battery systems. According to at least other selected embodiments, the present invention relates to a separator for a battery having a conductive deposition layer that is stable in electrolytes and under battery operating conditions.

[0238] The application can be embodied in other forms without departing from the spirit and essential characteristics thereof, the embodiments disclosed herein are therefore to be considered in all respects as illustrative and not restrictive, and the scope of the application is indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are embraced therein.

[0239] Improved battery separators for various lead-acid batteries are disclosed herein. The improved separators disclosed herein provide lead-acid batteries with significantly improved battery life, improved charge acceptance, improved oxidation resistance, improved surface conductivity, improved stiffness, improved wettability, and significantly reduced battery failure rates and acid stratification.

[0240] According to at least selected embodiments, aspects or objects, the present application or invention relates to new or improved porous membranes or substrates, separators, separators, composites, electrochemical devices, batteries, methods of making such membranes or substrates, separators and / or batteries, and / or methods of using such membranes or substrates, separators and / or batteries. According to at least certain embodiments, the present application relates to new or improved porous membranes with coatings, battery separators with coatings, separators, energy storage devices comprising such separators, batteries, lead acid batteries, methods of making such membranes, separators and / or batteries, and / or methods of using such membranes, separators and / or batteries. The disclosed separators and batteries can have improved charge acceptance, improved surface conductivity, improved oxidation resistance, reduced acid stratification, reduced black staining, improved wettability and / or improved stiffness.

[0241] According to at least selected embodiments, aspects or objects, the present application or invention relates to new or improved porous membranes or substrates, separators, separators, composites, electrochemical devices, batteries, methods of making such membranes or substrates, separators and / or batteries, and / or methods of using such membranes or substrates, separators and / or batteries. According to at least certain embodiments, the present application relates to new or improved porous membranes with coatings, battery separators with coatings, separators, energy storage devices comprising such separators, batteries, lead acid batteries, methods of making such membranes, separators and / or batteries, and / or methods of using such membranes, separators and / or batteries. The disclosed separators and batteries have improved charge acceptance, improved surface conductivity, improved oxidation resistance, reduced acid stratification, improved resistance to oxidation caused by metal contamination, reduced black staining, improved wettability and / or improved stiffness.

[0242] According to at least certain selected embodiments, the present invention relates to a battery separator that is a functionalized, coated, treated, etc. microporous polymer membrane to add at least one material, treatment, function or layer to at least one side thereof. In certain selected particular embodiments, the material, treatment, function or layer can or can not include a binder, can include one or more materials such as silica, silicon oxide, alumina, aluminum oxide, metals, metal oxides, conductive carbon materials, acid stable cellulose and / or the like, and / or can include one or more electrically conductive or non-conductive or insulating layers.

[0243] According to at least certain embodiments, a method of obtaining an improved separator is provided in which a treatment, material or layer is applied to a polymeric microporous membrane, a polyethylene (PE) microporous membrane, a woven or nonwoven material, a nonwoven glass mat, a nonwoven absorbent glass mat (AGM), a nonwoven or woven

[0244] at least one surface or side of the PET, cellulose nonwoven mat, and / or the like. The material, treatment, or layer can be applied by vapor deposition, chemical deposition, vacuum assisted methods, PVD, CVD, TD, DCD, PACVD, DLC, thin film coating or deposition techniques, nanofilm techniques, monatomic thick coating techniques, sol-gel, solvent coating, aqueous coating, and / or the like. In some embodiments, the material, treatment, coating, layer, or function is applied or added by a solventless method, a binderless method, or a solventless and binderless method. In other alternative embodiments, the layer is applied in the presence of a binder and / or solvent, which can be subsequently removed.

[0245] According to at least selected embodiments, the porous membrane having a porous or ionically conductive coating or layer is disposed as a battery separator in a lead acid battery and can improve the cycle life, starting capability, and high charge acceptance of the battery.

[0246] According to at least particular embodiments, the battery separators described herein relate to multi-layer or composite microporous membrane battery separators that can have excellent oxidation resistance and be stable in lead acid battery systems. According to at least other alternative embodiments, the present invention relates to a battery separator having a layer that increases oxidation resistance, improved oxidation resistance in the presence of metal ion contaminants such as chromium ions, reduced acid stratification, improved surface conductivity, improved charge acceptance, increased stiffness, runnability, and processability, and / or increased surface wettability.

[0247] According to at least selected embodiments, the present application or invention relates to a new, improved or optimized porous thin film, membrane or substrate, a functionalized, coated or treated porous thin film, membrane or substrate, a new, improved, optimized, functionalized or treated separator, separator, multi-layer separator, lead acid battery separator or composite, an electrochemical device, battery or cell including such thin film, membrane, substrate, separator, lead acid battery separator or composite, a new, improved or optimized combination or system of a plate or electrode having such thin film, membrane, substrate, separator, lead acid battery separator or composite, a method of making such thin film, membrane, substrate, separator, lead acid battery separator, composite, system, combination, cell, device and / or battery, and / or a method of using such thin film, membrane, substrate, separator, lead acid battery separator, composite, system, combination, cell, device and / or battery. According to at least certain embodiments, the present application relates to a new, improved or optimized, functionalized, coated or treated microporous membrane, battery separator, lead acid battery separator, separator and / or lead acid battery separator having at least one functionalized, coated or treated surface on at least one side, at least one coating, thin film, layer or material on at least one side, rib or surface thereof, and / or an energy storage device, battery, system, combination including such membrane, battery separator, lead acid battery separator, separator and / or lead acid battery separator, a method of making such separator, battery separator, lead acid battery separator, separator and / or lead acid battery separator, and / or a method of using such separator, battery separator, lead acid battery separator, separator, composite, combination, system, device, cell and / or battery, etc.

[0248] The foregoing written description of structures, devices and methods is presented for purposes of illustration only. The examples are presented to disclose exemplary embodiments, including the best mode, and to enable others skilled in the art to practice the application, including making and using any devices or systems, and performing any incorporated methods. The embodiments are not intended to be exhaustive or to limit the application to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teachings. The features described herein can be combined in any combination. The steps of the methods described herein can be performed in any order physically possible. The patentable scope of the present application is defined by the appended claims, and can include other examples that occur to those skilled in the art. Such other examples are intended to fall within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

[0249] The compositions and methods of the appended claims are not limited to the specific compositions and methods described herein as such may vary. It is intended that the claims cover all such compositions and methods falling within the scope of the claims. Any compositions and methods functionally equivalent to those described herein are within the scope of the claims. Various modifications beyond those shown and described herein are considered within the scope of the appended claims. Moreover, although specific steps, elements, components, or combinations of steps, elements, and components are described with reference to the representative embodiments disclosed herein, other combinations of steps, elements, and components are considered within the scope of the claims. Thus, the steps, elements, components, or combinations of steps, elements, and components, even if not expressly claimed, are considered disclosed.

[0250] As used in the specification and the appended claims, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. Ranges can be expressed herein as "about" one particular value, and / or "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are important and independently relevant, and that the ranges are not intended to be inclusive of the endpoint unless specifically indicated.

[0251] "Optional" or "optionally" means that the subsequently described event or circumstance can or can not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0252] Throughout the specification and claims, the word "comprise" and variations of the word, such as "comprising" and "comprises" means "including but not limited to," and is not intended to exclude, for example, additional additives, components, integers or steps. The terms "consisting essentially of and "consisting of can be used in place of "comprising" and "including" to provide more specific embodiments of the present application, and are also disclosed. "Exemplary" means "an example of" and is not intended to indicate a preferred or ideal embodiment. "Such as" is not used in a restrictive sense, but for explanatory or illustrative purposes.

[0253] Except where otherwise indicated, all numbers used herein to express geometrical shapes, dimensions and so forth are to be understood as preceeded by the word "about". Unless otherwise indicated, the use of relating to the application of the doctrine of equivalents, is not intended to limit the scope of the claims to the particular equivalent per se. Numbers expressing quantities of ingredients, properties such as physical properties, and so forth used herein are to be understood as being modified in all instances by the term "about". Except where otherwise indicated, the use of the word "about" is intended to indicate that the item in question can vary from the specified value by a reasonable amount, and is not intended to indicate that the item in question is limited to the specified value.

[0254] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The publications cited herein and their cited materials are specifically incorporated by reference.

Claims

1. A lead acid battery separator comprising a layer of an oil and an oxidation resistant material on its surface.

2. A lead-acid battery comprising the lead-acid battery separator of claim 1, wherein, The oxidation resistant material and the oil are released from the surface of the lead acid battery separator into the battery.

3. A lead acid battery separator comprising: a porous polyolefin membrane filled with an inert material; and a conductive layer of carbon structures with sufficient electrical conductivity deposited on the surface of the separator facing the negative electrode, on the ribs facing the positive electrode surface, on the laminates, or on the AGM separator in direct contact with the positive plate, the resulting conductive layer electrical conduction path is created mainly in the X-Y plane of the separator, not fully through the Z plane; the porous polyolefin membrane comprises an extruded mixture comprising about 30% by weight of the inert material.

4. The lead acid battery separator of claim 3, wherein, the conductive layer is applied to the ribs or laminate structure in the pasting paper, retention mat, AGM separator, or gauntlet, all of which are in intimate contact with the positive electrode; the conductive layer contains carbon structures on the separator ribs, AGM separator, or laminate structure in direct contact with the positive electrode; the porous polyolefin membrane comprises ribs, protrusions, or indentations; the conductive layer comprises one or more layers of silica, alumina, a metal, a metal oxide, a conductive carbon material, cellulose, and / or a mixture thereof; the metal oxide is selected from at least one of: aluminum oxide (AI2O3), boehmite AI0(OH), silicon oxide, a transition metal oxide, and combinations thereof; the metal oxide is a transition metal oxide and the metal is zinc or titanium; a different layer is applied on each side of the porous polyolefin membrane; and / or two layers are applied on one side of the porous polyolefin membrane.

5. The lead acid battery separator of claim 1, wherein, the porous polyolefin membrane is provided as an envelope or sleeve, the conductive layer is on the outer surface, the inner surface, or both surfaces of the envelope or sleeve; the carbon is electrically conductive, partially conductive, or semi-conductive.

6. The lead-acid battery separator of claim 1, wherein, oxidation resistance is provided by depositing aluminum oxide and silicon dioxide on the positive face of the separator; a reduction in black staining is provided by using less oil on one or both sides of the separator; and / or stiffness is provided to the separator by depositing aluminum oxide and silicon dioxide on one or both sides of the separator.

7. The lead-acid battery separator of claim 6 wherein, The vapor-deposited layer deposited on the porous polyolefin membrane is composed of individual atoms or molecules of a plurality of layers of inert metal elements, reactive metal elements, or metal oxide compounds; one or more layers applied in various sequences of metals and / or metal oxides in a thickness of less than 1 μm, a thickness of less than 0.5 μm, a thickness of less than or a thickness of less than .

8. A lead acid battery separator having a porous membrane filled with an inert material and a coating, wherein, one or more coatings are present on either side of the porous membrane; the thickness of the coating is less than 5 pm, 4 pm, 3 pm, 2 pm, 1 pm, 0.5 pm, or 0.25 pm; the coating is a material comprising: silica, fumed silica, silicon oxide, alumina, aluminum oxide, a metal, a metal oxide, cellulose, carbon, and a conductive carbon material; the coating further comprises a polymer, a binder, or a carrier material; the porous polyolefin membrane comprises an extruded mixture comprising about 30% by weight of the inert material.

9. The lead acid battery separator of claim 8, wherein, the conductive carbon material is selected from: graphite, graphene, carbon nanotubes, graphene oxide, carbon fibers, and combinations, blends, or mixtures thereof; The metal oxide is selected from the group consisting of bauxite, alumina (AI2O3), boehmite AI O(OH), silica, fumed silica, transition metal oxides, and combinations, blends, or mixtures thereof; The coating further comprises a carrier material comprising one or more of glass mat, fiber mat, synthetic mat, ceramic, and polymer; and / or The polymeric binder is an acrylic resin, PVDF, PVDF:HFP, PEO, PTFE, SBR, PVA, phenolic resin, or acrylate.

10. The lead-acid battery separator of claim 9, wherein, The porous membrane comprises one or more thermoplastic polymers, preferably the thermoplastic polymer comprises polyethylene.

11. The lead acid battery separator of claim 8, wherein, The porous membrane comprises ribs, serrations, embossing, corrugations, perforations, or dimples; The porous membrane comprises PE, PO, PVC, cellulose, rubber, glass mat, fiber mat, or AGM; The porous membrane comprises one or more additives or agents; and / or The porous membrane comprises no more than 20%, 18%, 16%, 14%, 12%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, or 0.5% by weight of processing oil.

12. The lead acid battery separator of any one of claims 3-10 having improved charge acceptance, improved surface conductivity, improved oxidation resistance, reduced acid stratification, improved resistance to metal contamination induced oxidation, reduced black staining, improved wettability, and / or improved stiffness.

13. A method of making the battery separator of any one of claims 3-10, comprising the steps of: extruding a mixture to form a porous polyolefin membrane comprising the extruded mixture, the extruded mixture comprising about 30 wt% of inert material; and applying at least one electrically conductive layer comprising electrically conductive carbon and at least one metal oxide on at least one side of the porous polyolefin membrane; the porous membrane having no more than 20% by weight of residual processing oil.

14. The method of claim 13, wherein, The electrically conductive layer is applied by dipping, blade, curtain coating, gravure printing, solvent coating, aqueous coating, organic coating, physical vapor deposition, atomic layer deposition, or chemical vapor deposition.

15. A lead acid battery comprising the lead acid battery separator of any one of claims 3-10.

16. The lead acid battery of claim 15 having improved charge acceptance, improved conductivity, improved cycle life, reduced acid stratification, improved resistance to metal contamination, reduced black staining, improved electrolyte wet-out or fill time, and combinations thereof.

17. A lead acid battery separator comprising: a porous polyolefin membrane filled with inert material; and a deposited layer comprising an inert metal element applied on the polymeric microporous membrane, the deposited layer being applied as an electrically conductive layer to the non-conductive porous polyolefin membrane, the electrically conductive layer having a thickness of less than 1 pm in total; the porous polyolefin membrane comprises an extruded mixture, the extruded mixture comprising about 30 wt% of inert material.

18. The lead-acid battery of claim 3 or 8, or the method of claim 13, wherein, the extruded mixture comprises about 30%, 50%, 60%, 70%, or 80% by weight of inert material; and the processing oil is no more than 60%, 50%, 45%, 35%, 30%, 25%, 20%, 15%, or 10% by weight.

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