Improved separator for reducing stratification in lead-acid batteries and improved battery containing same

Abstract

A lead-acid battery separator having a first array of ribs extending from a first side of the backweb and a second array of ribs extending from a second side of the backweb. The first array of ribs and the second array of ribs are both cross-machine direction (CMD) ribs. In a flooded lead-acid (FLA) or valve-regulated lead-acid (VRLA) battery, the CMD ribs extend in a direction parallel to the top and bottom of the battery. This separator helps reduce stratification problems, thereby enabling the FLA battery to be used as a supplemental battery or an enhanced flooded lead-acid (EFB) battery, and further improving VRLA performance when used as a supplemental battery.

Description

[Technical Field]

[0001] This application describes improved separators, separator membranes, coated membranes, silica-coated polyolefin membranes, silica-coated and carbon-coated polyolefin membranes, flat-sheet membranes, ribbed membranes, and cross-machine-direction (CMD) ribbed membranes for reducing stratification in lead-acid batteries, particularly flooded lead-acid batteries, reinforced flooded lead-acid batteries, or auxiliary lead-acid batteries, and improved batteries containing such improved separators, separator membranes, coated membranes, silica-coated polyolefin membranes, silica-coated and carbon-coated polyolefin membranes, flat-sheet membranes, ribbed membranes, and / or cross-machine-direction (CMD) ribbed membranes. [Background technology]

[0002] A battery operating at a partial state of charge is one that operates at a state of charge of about 65% to about 90% or less. Partial charging significantly reduces internal mixing of the electrolyte without the generation of gas bubbles, which can lead to stratification within the battery. Stratification often leads to accelerated sulfation, loss of capacity, damage to the battery plates, and ultimately battery failure.

[0003] In some instances, stratification can be avoided by using valve-regulated lead-acid (VRLA) technology, in which the acid is immobilized by a gelled electrolyte and / or an absorbent glass mat (AGM) battery separator system. In contrast to the free-flowing electrolyte of flooded lead-acid batteries, in VRLA batteries, the electrolyte is absorbed into fibers or fibrous materials, such as glass fiber mats, polymer fiber mats, or is a gelled electrolyte. However, VRLA battery systems are significantly more expensive to manufacture than flooded battery systems. VRLA-AGM technology may, in some cases, be more sensitive to overcharging, dry out in high heat, experience gradual capacity loss, and have low specific energy. Similarly, gelled VRLA technology may, in some cases, have high internal resistance and poor charge acceptance.

[0004] There is a growing need for 12V auxiliary lead-acid batteries, a critical on-board component in electric vehicles (EVs) and indeed in a variety of low-emission vehicles, such as hybrid vehicles. 12V auxiliary lead-acid batteries provide backup power for safety-related functions such as power steering and brake boost. Needless to say, these auxiliary batteries are used to power EV and non-EV electronic accessories, including comfort features such as radios, sound systems, security systems, cameras, and navigation systems.

[0005] These auxiliary batteries, due to the extreme demands placed on them, are operated at a partial state of charge and are therefore more susceptible to stratification as explained above. In some cases, stratification in these auxiliary batteries can even be worse than in other types of batteries that are also operated at a partial state of charge.

[0006] Therefore, there is a need to suppress stratification in general and in auxiliary cells in particular. Summary of the Invention [Problem to be solved by the invention]

[0007] Disclosed herein is a battery separator that, when used in a lead-acid battery operating at a partial state of charge, such as in an auxiliary battery, improves one or more of the following properties: improved stratification by reducing stratification; improved dynamic charge acceptance (DCA) as measured by the VW DCA performance test; reduced water loss as measured by the Volkswagon Water Loss Test VW 75073 (issued 03-2020); improved depth of discharge as found in section 7.7 of the 2010-04 edition of VW 75073 entitled "Cycles with 17.5% depth of discharge at (27+0 / -2)°C"; reduced residue formation; and improved oxidation resistance as measured by the PEROX 80 test described in section 22 of BCIS-03B. [Means for solving the problem]

[0008] In one aspect, a lead-acid battery separator comprises a backweb, a first array of ribs extending from a first side of the backweb, and a second array of ribs extending from a second side of the backweb. Both the first and second arrays of ribs can be cross-machine direction (CMD) ribs. In some embodiments, at least one of the first array of ribs and the second array of ribs comprises individual ribs having different heights. In other embodiments, one or both of the first array of ribs and the second array of ribs comprises continuous ribs, discontinuous ribs, or angled discontinuous ribs.

[0009] The separator backweb thickness is preferably within the range of 8 microns to 500 microns, 10 microns to 500 microns, 50 microns to 400 microns, or 100 microns to 400 microns. In some embodiments, the overall separator thickness, including ribs (if present), as measured by the BCI method (BCIS-03B Backweb Thickness Section 15 and Overall Thickness Section 16) is preferably within the range of 8 to 1200 microns, 10 to 1200 microns, 50 to 1100 microns, or 600 to 1100 microns.

[0010] In some embodiments, the battery separator is a filled polyolefin lead acid battery separator. In some embodiments, the filled polyolefin separator includes an oil in an amount of 5% to 20%. The aniline point of the oil can be between 80°C and 125°C.

[0011] In some embodiments, the filled polyolefin separator can include a siliceous filler. The ratio of siliceous filler to polyolefin can be from 2.5:1 to 5:1.

[0012] In some embodiments, the separator can include rubber, a rubber derivative, latex, a latex derivative, or a combination thereof in an amount of 1% to 6% by weight or 1% to 3% by weight.

[0013] The separator may be a cut piece separator, a sleeve separator, a wrap separator, or an envelope separator. When the separator is in a wrap or envelope shape, a through slit may be formed in the bottom of the envelope separator or the wrap separator.

[0014] The battery separator may include a surfactant, the surfactant being one or more selected from an ionic surfactant, a non-ionic surfactant, and an amphoteric surfactant.

[0015] The battery separator, in some embodiments, can include carbon on at least one of the first side and the second side.

[0016] In some other embodiments, the separator may comprise one or more selected from precipitated silica, dry pulverized silica, amorphous silica, fumed silica, friable silica, dispersible silica, alumina, talc, colloidal silica, superabsorbent polymers, and fish bone meal between the ribs on at least one of its first side or second side.

[0017] In another aspect, a lead-acid battery is described that includes the separator described hereinabove. In the battery, the CMD ribs extend parallel to the top and bottom of the battery. In embodiments where carbon is provided on one side of the separator, the side of the separator with the carbon thereon will face the negative electrode of the battery. In embodiments where silica is provided on one side of the separator, the side of the separator with the silica thereon will face the positive electrode of the battery. In other embodiments where silica is provided on one side of the separator, the side of the separator with the silica thereon will face the negative electrode of the battery.

[0018] The battery may be any flooded lead acid battery where stratification may be an issue, including enhanced flooded battery (EFB), starting, lighting and ignition (SLI) batteries, auxiliary batteries, etc.

[0019] In some embodiments, the battery may include a thickener in the battery's electrolyte.

[0020] In another aspect, a vehicle is described herein that includes the lead-acid battery described above. The lead-acid battery can be the vehicle's main or auxiliary battery. The vehicle can be a truck, a car, or an electric vehicle such as a truck or a car. In another aspect, the battery separator with CMD ribs described herein can be used in a valve-regulated lead-acid (VRLA) battery. The VRLA battery can include a composite separator including an absorbent glass mat (AGM) separator and a polyolefin separator with CMD ribs. In such an embodiment, the outward-facing surface of the polyolefin separator can include CMD ribs, and the surface in contact with the AGM separator does not require CMD ribs, but may have CMD ribs.

[0021] In another aspect, a vehicle is described herein that includes the VRLA battery described above. The lead-acid battery can be the main lead-acid battery or an auxiliary battery of the vehicle. The vehicle can be a truck, a car, or an electric vehicle.

[0022] In another embodiment, a lead-acid battery is disclosed that includes two positive plates, a negative plate between the two positive plates, and a separator. The separator includes a backweb, a first array of ribs extending from a first side of the backweb, and a second array of ribs extending from a second side of the backweb, at least one of the first or second arrays of ribs including cross-machine direction (CMD) ribs. The separator is coated on at least one side with a siliceous material. Additionally, the separator in this embodiment encapsulates the negative plate such that the CMD ribs face one or both of the positive plates and extend in a direction parallel to the top or bottom of the battery.

[0023] The siliceous material is not particularly limited and can be one or more selected from precipitated silica, dry pulverized silica, amorphous silica, fumed silica, friable silica, dispersible silica, and colloidal silica.

[0024] In another embodiment, a lead-acid battery is described that includes two positive plates, a negative plate between the two positive plates, and a separator that encases both positive plates. The separator includes a backweb, a first array of ribs extending from a first side of the backweb, and a second array of ribs extending from a second side of the backweb, at least one of the first or second rib arrays including cross-machine direction (CMD) ribs. Additionally, at least one side of the separator is coated with a siliceous material. The CMD ribs of the separator in this embodiment face the positive plates and extend in a direction parallel to the top or bottom of the battery.

[0025] The siliceous material is not particularly limited and can be one or more selected from precipitated silica, dry pulverized silica, amorphous silica, fumed silica, friable silica, dispersible silica, and colloidal silica.

[0026] In another embodiment, a battery is described that includes at least one positive plate, at least one negative plate, and a battery separator. The separator includes a profile on at least one side that exhibits a surface area increase of 35% or more, 40% or more, 60% or more, or 80% or more compared to a flat separator. Additionally, the separator is coated on at least one or both sides with silica. At least certain embodiments, aspects, or objects describe or provide improved separators, separator membranes, coated membranes, silica-coated polyolefin membranes, silica-coated and carbon-coated polyolefin membranes, flat-sheet membranes, ribbed membranes, and / or cross-machine-direction (CMD) ribbed membranes for reducing stratification in lead-acid batteries, particularly flooded lead-acid batteries, reinforced flooded lead-acid batteries, or auxiliary lead-acid batteries, and / or improved batteries containing such improved separators, separator membranes, coated membranes, silica-coated polyolefin membranes, silica-coated and / or carbon-coated polyolefin membranes, flat-sheet membranes, ribbed membranes, and / or cross-machine-direction (CMD) ribbed membranes. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 includes illustrative cross-sectional views of exemplary battery separators described herein and their orientation relative to the top and bottom of a battery. [Figure 2] FIG. 2 includes an illustrative cross-sectional and side view including multiple views of an exemplary battery separator described herein. [Figure 3] FIG. 3 is a schematic side view of a valve-regulated lead-acid battery (VRLA) including an exemplary separator described herein. [Figure 4] FIG. 4 is a schematic side view of a flooded lead-acid battery including an exemplary separator described herein. [Figure 5] FIG. 5 is a schematic side view of a flooded lead-acid battery including an exemplary separator described herein. [Figure 6] FIG. 6 is a schematic side view of a flooded lead-acid battery including an exemplary separator described herein. [Figure 7] FIG. 7 is a schematic side view of a flooded lead-acid battery including an exemplary separator described herein. [Figure 8] FIG. 8 is a schematic side view of a valve-regulated lead-acid battery (VRLA) including an exemplary separator described herein. [Figure 9] FIG. 9 is a schematic side view of a valve-regulated lead-acid battery (VRLA) including an exemplary separator described herein. [Figure 10] FIG. 10 is a schematic side view of a valve-regulated lead-acid battery (VRLA) including an exemplary separator described herein. [Figure 11] FIG. 11 is a schematic side view of a flooded lead-acid battery including an exemplary separator described herein. [Figure 12] FIG. 12 is a schematic side view of an embodiment of a pocket or envelope described herein, such as a flooded lead acid battery including an exemplary separator described herein. [Figure 13] FIG. 13 contains cross-sectional HIROX microscope images of Profile 1 described herein with and without a silica coating on the surface of Profile 1. [Figure 14]FIG. 14 includes cross-sectional HIROX microscope images of Profile 2 described herein with and without a silica coating on the surface, as well as a top view of Profile 2. [Figure 15] FIG. 15 includes cross-sectional HIROX microscope images of Profile 3 described herein with and without a silica coating on the surface, as well as a top view of Profile 3. [Figure 16] FIG. 16 is a graph showing the percent surface area increase compared to a flat microporous sheet without a rib profile. [Figure 17] FIG. 17 is a graph showing average voltage as a function of cycles for a 17.5 PSoC EoD voltage test in accordance with embodiments described herein. [Figure 18] FIG. 18 is a graph showing average voltage as a function of cycle life for 17.5 PSoC EoD voltage testing in embodiments described herein. [Figure 19] FIG. 19 is a graph showing average voltage as a function of cycle life for a 17.5 PSoC EoD voltage test in accordance with embodiments described herein. [Figure 20] FIG. 20 is a table showing the average acid pickup percentage for embodiments described herein. DETAILED DESCRIPTION OF THE INVENTION

[0028] Improved battery separator for flooded lead acid (FLA) batteries. Disclosed herein is an improved battery separator for use in flooded lead-acid batteries that are prone to stratification problems. Examples of flooded lead-acid batteries that may experience stratification problems include, but are not limited to, enhanced flooded batteries (EFBs) and starting, lighting, and ignition (SLI) batteries. The improved battery separator described herein allows FLA batteries (see FIG. 4) to be used as auxiliary batteries in vehicles or other devices. As discussed above, stratification in auxiliary batteries can be worse than in other types of batteries (e.g., primary batteries), making it difficult to use FLA batteries as auxiliary batteries.

[0029] One improved battery separator described herein has the following structure: a backweb and cross-machine direction (CMD) ribs extending from both sides of the backweb, as shown in Figures 1 and 2, which include an exemplary battery separator with CMD ribs on both sides. When incorporated into a battery, the CMD ribs extend parallel to the top and bottom of the battery.

[0030] The backweb thickness of the battery separators described herein may, in some embodiments, preferably be from about 100 microns to about 400 microns, 100 microns to 350 microns, 100 microns to 300 microns, 100 microns to 250 microns, 100 microns to 200 microns, or 100 microns to 150 microns. Backweb thickness is measured using the BCI method (BCIS-03B Backweb Thickness Section 15).

[0031] The overall thickness of the battery separator described herein is calculated by adding the backweb thickness, the height of the highest rib on the first side, and the height of the highest rib on the second side. See FIG. 1. It is measured using the BCI method (BCIS-03B Overall Thickness Section 16). Preferably, the overall thickness is approximately equal to the plate spacing required for the battery. The overall thickness is within the range of about 500 microns to about 1100 microns, 500 microns to 1000 microns, 500 microns to 900 microns, 500 microns to 800 microns, 500 microns to 700 microns, or 500 microns to 600 microns. In auxiliary batteries, the plate spacing is typically about 600 microns to 1000 microns, so for this application, the overall thickness should fall within this range.

[0032] The ribs on the first side and the ribs on the second side may be the same or different. For example, the CMD ribs may be continuous on both sides, continuous on one side but not the other, discontinuous on both sides, or discontinuous on one side but continuous on the other. The CMD ribs on the first and second sides may be the same height or different heights. In addition, rib heights may be provided on the same side. Furthermore, the heights of the CMD ribs on a particular side may be the same or different. See, for example, FIG. 1D, E, and F. In some embodiments, the spacing of the CMD ribs on the first side may be the same or different from the spacing on the second side. Rib spacing may also vary on the same side. Combinations of different rib heights and spacings may be combined on one side.

[0033] The spacing between the ribs is not particularly limited, but is preferably 0.25 mm to 12 mm, 0.5 mm to 12 mm, 1 mm to 12 mm, 2 mm to 12 mm, 3 mm to 12 mm, 4 mm to 12 mm, 5 mm to 12 mm, 6 mm to 12 mm, 7 mm to 12 mm, 8 mm to 12 mm, 9 mm to 12 mm, 10 mm to 12 mm, or 11 mm to 12 mm.

[0034] In embodiments including discontinuous ribs, the ribs may be angled or not. For example, for angled ribs, the rib angle may be greater than or equal to 1 degree or less than 180 degrees, or the rib angle may be greater than or equal to 181 degrees but less than 360 degrees.

[0035] The composition of the lead-acid battery separator disclosed herein is not particularly limited, but preferably includes natural or synthetic materials, such as polyolefin, polyethylene, polypropylene, phenolic resin, PVC, rubber, synthetic wood pulp (SWP), glass fiber, cellulosic fiber, or a combination thereof. The polyolefin is preferably, but not limited to, polyethylene or polypropylene. In some preferred embodiments, the polyethylene is high molecular weight polyethylene or ultra-high molecular weight polyethylene.

[0036] In some preferred embodiments, the battery separator may be a filled polymer lead-acid battery separator, preferably a filled polyolefin separator. The filled polyolefin separator comprises a polyolefin and a filler. Suitable fillers include siliceous fillers, such as silica, mica, montmorillonite, kaolinite, asbestos, talc, diatomaceous earth, vermiculite, natural and synthetic zeolites, cement, calcium silicate, clay, aluminum silicate, sodium aluminum silicate, aluminum polysilicate, alumina silica gel, and glass particles. These siliceous fillers are water-soluble. In addition to siliceous fillers, other particulate, substantially water-insoluble fillers may also be used. Examples of such optional fillers include carbon black, activated carbon, carbon fiber, charcoal, graphite, titanium oxide, iron oxide, copper oxide, zinc oxide, lead oxide, tungsten, antimony oxide, zirconia, magnesia, alumina, molybdenum disulfide, zinc sulfide, barium sulfate, strontium sulfate, calcium carbonate, and magnesium carbonate.

[0037] In embodiments in which a siliceous filler is used, the ratio of siliceous filler to polyolefin is from 2.5:1.0 to 5.0:1.0, from 3.0:1.0 to 5.0:1.0, from 3.5:1.0 to 5.0:1.0, from 4.0:1.0 to 5.0:1.0, or from 4.5:1.0 to 5.0:1.0.

[0038] Lead-acid battery separators may contain a plasticizer, which is typically a liquid at room temperature and is usually a process oil such as paraffinic oil, naphthenic oil, or aromatic oil. The amount of oil in the final battery separator may be 5% to 20%, 7% to 20%, 10% to 20%, 13% to 20%, 15% to 20%, 17% to 20%, or 18% to 20%. The process oil may have an aniline point of 50°C to 125°C, 60°C to 125°C, 70°C to 125°C, 80°C to 125°C, 90°C to 125°C, 100°C to 125°C, 110°C to 125°C, or 120°C to 125°C.

[0039] In some embodiments, one or more of rubber, rubber derivatives, latex, and latex derivatives may be added in an amount of 1% to 3%, 1.5% to 3%, 2% to 3%, or 2.5% to 3%.

[0040] As used herein, rubber refers to rubber, latex, natural rubber, synthetic rubber, crosslinked or uncrosslinked rubber, cured or uncured rubber, crumb or ground rubber, or mixtures thereof. Exemplary natural rubbers may include one or more blends of polyisoprene commercially available from various suppliers. Exemplary synthetic rubbers include methyl rubber, polybutadiene, chloropene rubbers, butyl rubber, bromobutyl rubber, polyurethane rubber, epichlorohydrin rubber, polysulfide rubber, chlorosulfonyl polyethylene, polynorbornene rubber, acrylate rubber, fluororubber, and silicone rubber, as well as copolymer rubbers such as styrene / butadiene rubber, acrylonitrile / butadiene rubber, ethylene / propylene rubber ("EPM" and "EPDM"), and ethylene / vinyl acetate rubber. The rubber may be crosslinked or uncrosslinked; in certain preferred embodiments, the rubber is uncrosslinked. In certain embodiments, the rubber may be a blend of crosslinked and uncrosslinked rubber.

[0041] In some embodiments, the separator includes a surfactant therein, thereon, or both therein and thereon, the surfactant including one or more selected from ionic surfactants, nonionic surfactants, and amphoteric surfactants.

[0042] The nonionic surfactant is not particularly limited, and examples thereof include fatty alcohols, cetyl alcohol, stearyl alcohol, pentaethylene glycol monododecyl ether, polyoxypropylene glycol alkyl ethers, polyoxyethylene glycol, octylphenol ether, polyoxyethylene glycol alkyl ethers, octaethylene glycol monododecyl ether, polyoxyethylene glycol alkylphenol ethers, polyoxyethylene glycol sorbitan alkyl esters, oleyl alcohol, polyethylene glycol block copolymers, polypropylene glycol block copolymers, glucoside alkyl ethers, decyl glucoside, lauryl glucoside, octyl glucoside, nonoxynol-9, glycerol alkyl esters, polysorbates, sorbitan alkyl esters, glyceryl laurate, cocamide, costearyl alcohol, alcohols), methallylated terminal nonionic surfactants, polyol fatty acid esters, polyethoxylated esters, polyethoxylated fatty alcohols, alkyl polysaccharides, alkyl polyglycosides, amine ethoxylates, sorbitan fatty acid ester ethoxylates, organosilicone surfactants, ethylene vinyl acetate terpolymers, ethoxylated alkylaryl phosphate esters, sucrose esters of fatty acids, polyethoxylated alcohols, polyethylene oxide, acid-soluble sugars, sucrose esters of fatty acids, organic fatty acids, hydroxyl acids, nonionic surfactants, octylphenol ethoxylate surfactants, octylphenol ethoxylate nonionic surfactants, and combinations thereof.

[0043] In some embodiments, the nonionic surfactant has a cloud point rating of greater than about 15°C, greater than about 20°C, or greater than about 25°C.

[0044] In some embodiments, the nonionic surfactant may have the following structure: [ka]

[0045] In the above structure, n may be an integer of 5-20 or 9-17, m may be an integer of 1-15 or 6-10, and p may be an integer of 0-10 or 0-7.

[0046] The ionic surfactant may be a cationic surfactant, an anionic surfactant, or an amphoteric surfactant.

[0047] In some embodiments, the ionic surfactant is selected from the group consisting of sulfates, alkyl sulfates, ammonium lauryl sulfate, sodium lauryl sulfate, alkyl ether sulfates, sodium laureth sulfate, sulfonates, docusate, dioctyl sodium sulfosuccinate, alkyl benzene sulfonates, phosphates, alkyl ether phosphates, carboxylates, alkyl carboxylates, fatty acid salts, sodium stearate, sodium lauroyl sarcosinate, alkyl trimethylammonium, cetyl pyridinium, polyethoxylated tallow amine, benzalkonium, benzethonium, dimethyl dioctadecane, The alkyl ester may be at least one selected from the group consisting of ammonium; dioctadecyldimethylammonium salts of alkyl sulfates; alkylarylsulfonate salts; alkylphenol-alkylene oxide adducts; soaps; alkyl-naphthalene-sulfonate salts; one or more sulfosuccinates, such as anionic sulfosuccinates; dialkyl esters of sulfosuccinate salts; amino compounds (primary, secondary, or tertiary amines; quaternary amines; block copolymers of ethylene oxide and propylene oxide; various polyethylene oxides; salts of mono- and di-alkyl phosphate esters, and mixtures thereof).

[0048] In some embodiments, the ionic surfactant may be an anionic surfactant having the following structure: [ka] In the formula, n is an integer of 0 to 10, m is an integer of 0 to 10, R1 is H, a C1 to C10 linear or branched saturated or unsaturated alkyl group, a C1 to C10 fatty alcohol, a C1 to C10 alcohol, or an aromatic group, R2 is H, a C1 to C10 linear or branched saturated or unsaturated alkyl group, a C1 to C10 linear or branched saturated or unsaturated fatty alcohol, a C1 to C10 linear or branched saturated or unsaturated alcohol, or an aromatic group, n and m are the same or different, R1 and R2 are the same or different, R3 is hydrogen or methyl, R4 is hydrogen or methyl, R3 and R4 are the same or different, and X is a negatively charged group such as SO3-, COO-, or PO4-2. Positive counterions to anionic surfactants also exist, and Na + , K. + , Li + , NH4 + , Ca 2+ , Mg 2+ It may be at least one of the following:

[0049] In some embodiments, the ionic surfactant may be an anionic surfactant having the formula: [ka]

[0050] The surfactant can be added in an amount of 15 grams per square meter (gsm) or less, 14 gsm or less, 13 gsm or less, 12 gsm or less, 11 gsm or less, 10 gsm or less, 9 gsm or less, 8 gsm or less, 7 gsm or less, 6 gsm or less, 5 gsm or less, 4 gsm or less, 3 gsm or less, 2 gsm or less, or 1 gsm or less. The use of surfactants can improve the function of flooded lead-acid batteries, for example, by reducing water loss.

[0051] In some other embodiments, carbon may be provided on one or both sides of the separator. The carbon may be provided to a thickness of less than 10 microns, less than 9 microns, less than 8 microns, less than 7 microns, less than 6 microns, less than 5 microns, less than 4 microns, less than 3 microns, less than 2 microns, or less than 1 micron. The coating weight may be 15 gsm or less, 14 gsm or less, 13 gsm or less, 12 gsm or less, 11 gsm or less, 10 gsm or less, 9 gsm or less, 8 gsm or less, 7 gsm or less, 6 gsm or less, 5 gsm or less, 4 gsm or less, 3 gsm or less, 2 gsm or less, or 1 gsm or less. The coated surface may or may not appear cracked. In some preferred embodiments, carbon may be provided on the side of the separator facing the negative electrode of a flooded lead-acid battery. This arrangement may improve the charge acceptance of the battery. This arrangement is shown in FIG. 5.

[0052] In some embodiments, the separator can be a cut-piece separator, a sleeve separator, a wrap separator, or a pocket or envelope separator. In embodiments where the separator is a wrap or envelope separator, a slit or opening can be formed in the bottom of the separator (i.e., the portion closest to the bottom of the battery). The slit or opening improves mixing by allowing the acid to enter the wrap or envelope separator from the bottom while the wrap or envelope separator holds the electrode plates.

[0053] In some embodiments, a gelling agent or thickener can be added to a flooded lead-acid battery. For example, the gelling agent or thickener can be added to the electrolyte via direct addition to the electrolyte or via a separator. FIG. 6 illustrates an embodiment in which the gelling agent or thickener is added via a separator. The gelling agent or thickener increases the viscosity of the electrolyte. A more viscous electrolyte (acid) is believed to retard stratification and may adhere to the separator. This is expected to further enhance the benefits of the invention described herein.

[0054] In other embodiments, one or more materials may be provided between at least one pair of ribs on the first or second side of the separator. The space between at least one pair of ribs may be partially or completely filled with the material. See, for example, FIG. 7, which illustrates "partial filling." In some embodiments, the material may be one or more selected from precipitated silica, dry pulverized silica, amorphous silica, fumed silica, crushed silica, dispersed silica, alumina, talc, superabsorbent polymers, and fish bone meal. The superabsorbent polymer may be provided as a powder, fiber, filament, liquid, or precursor chemical. It is believed that these materials absorb and even hold in place the electrolyte (acid), thereby further enhancing the benefits of the present invention. The material used is not particularly limited, as long as it is acceptable for use in flooded lead-acid batteries and absorbs (and in some cases retains) the acid. The material may be provided with or without a binder. Other additives may or may not be added.

[0055] According to one particular embodiment, aspect, or purpose, the coated membrane or coated battery separator has a silica coating on one or both sides of a microporous polyolefin flat sheet membrane, such as a silica-filled PE membrane.

[0056] According to certain other embodiments, aspects, or objects, the coated membrane or coated battery separator has a silica coating on one side and a carbon coating on the other side of a microporous polyolefin flat sheet membrane, such as a silica-filled PE membrane.

[0057] According to yet another particular embodiment, aspect, or object, the coated membrane or coated battery separator has a silica coating on both sides of a microporous polyolefin flat sheet membrane, such as a silica-filled PE membrane.

[0058] According to selected embodiments, aspects, or objectives, the lead acid battery separator comprises: a polyolefin backweb; a silica coating on at least one side of the backweb; Equipped with. The above battery separator having a silica coating on both sides of the backweb. The above battery separator having a carbon coating on the other side of the backweb. The above battery separator having ribs or protrusions on at least one side of the backweb. The battery separator above, having a backweb thickness of 10 to 500 microns. The above battery separator, wherein the thickness of the entire separator including any ribs is 10 to 1200 microns.

[0059] According to other selected embodiments, aspects, or objects, the flat sheet or ribless polyolefin membrane comprises: a polyolefin backweb; a silica coating on at least one side of the backweb; Equipped with. The above flat sheet having a silica coating on both sides of the backweb. The above flat sheet having a carbon coating on the other side of the backweb. The above flat sheet having a back web thickness of 10 to 500 microns.

[0060] Improved battery separator for valve-regulated lead-acid (VRLA) batteries. As discussed below, the improved battery separator can also be used in valve-regulated lead-acid (VRLA) batteries, which are a type of battery that typically do not experience stratification problems, or do not experience stratification problems to the same extent as flooded lead-acid batteries.

[0061] VRLA batteries are structurally different from flooded lead-acid batteries. For example, one difference is that VRLA batteries are sealed, while flooded batteries are not. Another notable difference is that the electrolyte in VRLA batteries is immobilized, while the electrolyte in flooded lead-acid batteries is free-flowing.

[0062] In some embodiments herein, a VRLA battery includes a positive electrode and a negative electrode, and both a VRLA separator (i.e., an absorbent glass mat (AGM) separator) between the positive and negative electrodes and the improved separator described herein above. The improved separator described herein may include cross-machine direction (CMD) ribs that run parallel to the top and bottom of the battery. The CMD ribs may face toward the VRLA / AGM separator and / or face away from the VRLA / AGM separator. See Figures 3, 8, 9, and 10. In some preferred embodiments, the CMD ribs may be provided facing away from the VRLA or AGM separator. See Figures 8 and 9, where the CMD ribs face only away from the VRLA or AGM separator. Benefits of this arrangement can include reducing the degree of compression of the separator, and additional benefits include improving or even eliminating stratification problems. If the CMD ribs face the positive electrode, this can also aid in positive electrode active material (PAM) shedding or PAM shedding.

[0063] Batteries and vehicles As mentioned above, the battery separators described herein can be used in either flooded or valve regulated lead acid batteries.

[0064] In a preferred embodiment, the battery separators described herein are used in flooded lead-acid batteries where reduced stratification is desired. This may include enhanced flooded batteries (EFBs), starting-lighting-ignition (SLI) batteries, and the like. The battery may be a main battery or an auxiliary battery. The improved battery separators described herein may enable the use of flooded lead-acid batteries as auxiliary batteries, which is currently difficult. Auxiliary batteries, as will be understood by those skilled in the art, may be backup, but are not primarily responsible for starting the vehicle engine.

[0065] In other preferred embodiments, the battery separators described herein can be used in valve-regulated lead acid (VRLA) batteries, particularly VRLA batteries for use as auxiliary batteries in vehicles. The separators can also be used in VRLA batteries that are the main batteries in vehicles.

[0066] Vehicles described herein may include trucks, cars, electric vehicles, or electric trucks, etc. [Example]

[0067] To prepare the examples, three different silica-filled polyethylene separators containing 5 to 20% processing oil were obtained. The separators had three different rib profiles: Profile 1, Profile 2, and Profile 3.

[0068] In Profile 1 (NX), the rib profile on one side of the separator is a continuous vertical rib with a pitch of approximately 7.3 mm between adjacent ribs. The rib profile on the other side is a continuous rib that runs perpendicular to the ribs on the opposite side (i.e., a cross rib). See Figure 13.

[0069] In Profile 2 (19X), the rib profile on one side of the separator is a discontinuous vertical rib with a pitch of approximately 3.5 mm between adjacent ribs. The rib profile on the other side is a continuous rib that runs perpendicular to the ribs on the opposite side (i.e., a cross rib). See Figure 14.

[0070] In Profile 3 (38X), the rib profile on one side of the separator is a discontinuous vertical rib with a pitch of approximately 1.8 mm between adjacent ribs. The rib profile on the other side is a continuous rib that runs perpendicular to the ribs on the opposite side (i.e., a cross rib). See Figure 15.

[0071] Surface area calculation: Separators with Profile 1, Profile 2, and Profile 3 with rib dimensions (e.g., height, pitch, width, etc.) obtained using a Hirox microscope. A sample area of the separator (e.g., 2 inches x 2 inches) was used for the measurements. The surface area is compared to a flat separator (e.g., no rib profile). Figure 16 shows the surface area increase compared to a flat separator (0% increase).

[0072] Acid Capture / Uptake Percentage: The separator was cut into 2-inch x 2-inch pieces, dried in an exhaust oven at 110°C for 5 minutes, and then weighed. Initial The sample was then immersed in sulfuric acid with a specific gravity of 1.28 for 10 minutes. The sample was then patted dry with four paper towels and hung to dry for 15 seconds. The weight of the second weighing was Final The percent acid scavenging was calculated using the following formula: (weight Final -weight Initial ) / weight Initial ×100.

[0073] Examples 1a, 1b, and 1c (Control): A separator having Profile 1 was prepared and a battery cell was fabricated with two positive plates and one negative plate. The negative plate was wrapped with the separator so that the cross ribs faced the negative plate and the other rib profile faced the positive plate. An example similar to Examples 1a, 1b, and 1c is illustrated in Figure 12. In the battery cell, the cross ribs run parallel to the top and bottom of the battery cell.

[0074] Examples 2a, 2b, and 2c: A separator with profile 1 was prepared and a battery cell was fabricated with two positive plates and one negative plate. The negative plate was wrapped with the separator so that the cross ribs faced the negative plate and the other rib profile faced the positive plate. In this example, the side of the separator facing the positive plate was coated with a layer of silica. In the battery cell, the cross ribs ran parallel to the top and bottom of the battery cell.

[0075] Examples 3a, 3b, and 3c (control): A separator with Profile 2 was prepared and a cell was fabricated with two positive plates and one negative plate. The negative plate was wrapped with the separator so that the cross ribs faced the negative plate and the other rib profile faced the positive plate. In the battery cell, the cross ribs ran parallel to the top and bottom of the battery cell.

[0076] Examples 4a, 4b, and 4c (control): A separator with Profile 2 was prepared and a cell was fabricated with two positive plates and one negative plate. The negative plate was wrapped with the separator so that the cross ribs faced the positive plate and the other rib profile faced the negative plate. In the battery cell, the cross ribs ran parallel to the top and bottom of the battery cell.

[0077] Examples 5a, 5b, and 5c: A separator with profile 2 was prepared and a battery cell was fabricated with two positive plates and one negative plate. The negative plate was wrapped with the separator so that the cross ribs faced the negative plate and the other rib profile faced the positive plate. The side of the separator facing the positive plate was coated with a layer of silica. In the battery cell, the cross ribs ran parallel to the top and bottom of the battery cell.

[0078] Examples 6a, 6b, and 6c: A separator with profile 2 was prepared and a battery cell was fabricated with two positive plates and one negative plate. The negative plate was wrapped with the separator so that the cross ribs faced the positive plate and the other rib profile faced the negative plate. The side of the separator facing the negative plate was coated with a layer of silica. In the battery cell, the cross ribs ran parallel to the top and bottom of the battery cell.

[0079] Examples 7a, 7b, and 7c: A separator with profile 2 was prepared and a battery cell was fabricated with two positive plates and one negative plate. The negative plate was wrapped with the separator so that the cross ribs faced the negative plate and the other rib profile faced the positive plate. The side of the separator facing the negative plate was coated with a layer of silica. In the battery cell, the cross ribs ran parallel to the top and bottom of the battery cell.

[0080] Examples 8a, 8b, and 8c: A separator with profile 2 was prepared and a battery cell was fabricated with two positive plates and one negative plate. The negative plate was wrapped with the separator so that the cross ribs faced the positive plate and the other rib profile faced the negative plate. The side of the separator facing the positive plate was coated with a layer of silica. In the battery cell, the cross ribs ran parallel to the top and bottom of the battery cell.

[0081] Examples 9a, 9b, and 9c (control): A separator with profile 3 was prepared and a battery cell was fabricated with two positive plates and one negative plate. The negative plate was wrapped with the separator so that the cross ribs faced the negative plate and the other rib profile faced the positive plate. In the battery cell, the cross ribs ran parallel to the top and bottom of the battery.

[0082] Examples 10a, 10b, and 10c: A separator with profile 3 was prepared and a battery cell was fabricated with two positive plates and one negative plate. The negative plate was wrapped with the separator so that the cross ribs faced the negative plate and the other rib profile faced the positive plate. The side of the separator facing the positive plate was coated with a layer of silica. In the battery cell, the cross ribs ran parallel to the top and bottom of the battery.

[0083] A similar example to the above may be made in which two positive plates are wrapped each instead of one negative plate.

[0084] Tests and Results The battery cells from each example were tested according to the 17.5% partial state of charge (PSoC) end-of-discharge (EoD) test. This test is described in VW 75073, 2010-04 edition, section 7.7, entitled "Cycles with 17.5% depth of discharge at (27+0 / -2)°C." Results for each example are reported as average values (e.g., 10a, 10b, and 10c) and are shown in Figure 17. Figure 18 includes selected examples from Figure 17 and shows that the performance of the silica-coated examples improved as the surface area of the separator profile increased. The average end-of-discharge voltage was as follows: Example 10 (Profile 3) > Example 5 (Profile 2) > Example 2 (Profile 1). As shown in Figure 16, Profile 3 exhibits a larger surface area compared to Profile 2 and a significantly larger increase in surface area compared to Profile 1. It is unexpected that the use of separators with a surface area increase profile (e.g., 35% or more surface area increase compared to flat sheets) and silica coatings results in significantly better results when battery cells are tested to a 17.5% partial state of charge (PSoC) end of discharge (EoD).

[0085] Figure 19 also includes examples selected from Figure 17 to illustrate the following effects. For example, it shows that adding a silica coating to an embodiment in which the cross ribs face the positive plate dramatically improves performance. For example, compare Example 4 (cross ribs facing the positive electrode, no silica coating) with Example 6 (cross ribs facing the positive electrode, silica coating facing the negative electrode) and Example 8 (cross ribs facing the positive electrode, silica coating also facing the positive electrode). Notably, Example 4 is one of the worst-performing examples, while Examples 6 and 8 unexpectedly perform best. The location of the silica coating does not appear to matter, yet it is necessary for improved performance. It is also noteworthy that Figure 20 shows that while there was little statistically significant difference in the overall average acid uptake / scavenging percentage, the performance of the samples was very different in the 17.5% partial state-of-charge (PSoC) end-of-discharge (EoD) test, indicating differences in stratification among the examples.

[0086] At least certain embodiments, aspects, or objects describe or provide improved separators, separator membranes, coated membranes, silica-coated polyolefin membranes, silica-coated and carbon-coated polyolefin membranes, flat-sheet membranes, ribbed membranes, and cross-machine-direction (CMD) ribbed membranes for reducing stratification in lead-acid batteries, particularly flooded lead-acid batteries, reinforced flooded lead-acid batteries, or auxiliary lead-acid batteries, and improved batteries containing such improved separators, separator membranes, coated membranes, silica-coated polyolefin membranes, silica-coated and carbon-coated polyolefin membranes, flat-sheet membranes, ribbed membranes, and / or cross-machine-direction (CMD) ribbed membranes.

[0087] At least selected embodiments, aspects, or objects describe or provide a lead-acid battery separator having a first array of ribs extending from a first side of a backweb and a second array of ribs extending from a second side of the backweb. The first array of ribs and the second array of ribs are both cross-machine direction (CMD) ribs. In a flooded lead-acid battery (FLA), an reinforced flooded lead-acid battery (EFB), or a valve-regulated lead-acid battery (VRLA), the CMD ribs extend in a direction parallel to the top and bottom of the battery. This separator helps reduce stratification problems, thereby enabling the FLA battery to be used as a supplemental battery or a reinforced flooded lead-acid battery (EFB), and further improving VRLA performance when used as a supplemental battery.

[0088] Many different arrangements of the various components and / or steps shown and described, as well as those not shown, are possible without departing from the scope of the following claims. The embodiments of the present technology have been described with the intent to be illustrative and not restrictive. Alternative embodiments will become apparent upon reference to this disclosure. Alternative means of carrying out the foregoing may be completed without departing from the scope of the following claims. It is contemplated that certain features and subcombinations are useful and may be employed without reference to other features and subcombinations and still be within the scope of the claims.

Claims

1. A lead-acid battery separator, a first array of ribs extending from a first side of the backweb; a second array of ribs extending from a second side of the backweb, wherein the first array of ribs and the second array of ribs are both cross-machine direction (CMD) ribs, a siliceous material is provided between the ribs on at least one of the first side or the second side of the backweb, and the siliceous material is one or more selected from precipitated silica, dry pulverized silica, amorphous silica, fumed silica, friable silica, and dispersible silica.

2. 10. The lead acid battery separator of claim 1, wherein the backweb has a thickness of from 100 microns to 400 microns.

3. 3. The lead acid battery separator of claim 2, wherein the battery separator has an overall thickness of between 600 microns and 1100 microns.

4. 10. The lead acid battery separator of claim 1, wherein at least one of the first array of ribs and the second array of ribs comprises individual ribs having different heights.

5. 10. The lead acid battery separator of claim 1, wherein one or both of the first array of ribs and the second array of ribs comprises continuous ribs.

6. 10. The lead acid battery separator of claim 1, wherein one or both of the first array of ribs and the second array of ribs comprises discontinuous ribs.

7. 7. The lead acid battery separator of claim 6, wherein said discontinuous ribs are angled discontinuous ribs.

8. 10. The lead acid battery separator of claim 1, wherein said battery separator is a filled polyolefin lead acid battery separator.

9. 10. The lead acid battery separator of claim 8, wherein said battery separator comprises a siliceous filler.

10. 10. The lead acid battery separator of claim 9, wherein the ratio of siliceous filler to polyolefin is from 2.5:1 to 5:

1.

11. 10. The lead acid battery separator of claim 1, wherein the amount of oil in said battery separator is 5% to 20%.

12. 12. The lead acid battery separator according to claim 11, wherein the aniline point of said oil is between 80°C and 125°C.

13. 10. The lead acid battery separator of claim 1, wherein the amount of rubber, rubber derivative, latex, or latex derivative in said battery separator is 1% to 3%.

14. 10. The lead acid battery separator of claim 1, wherein the separator is a cut piece separator, a sleeve separator, a wrap separator, or an envelope separator.

15. 10. The lead acid battery separator according to claim 1, wherein the separator is a wrap separator or an envelope separator with one or more slits at the bottom.

16. 10. The lead acid battery separator of claim 1, wherein the battery separator comprises a surfactant, the surfactant being one or more selected from an ionic surfactant, a nonionic surfactant, and an amphoteric surfactant.

17. 10. The lead acid battery separator of claim 1, comprising carbon on at least one of said first side and said second side.

18. 10. The lead acid battery separator of claim 1, comprising one or more selected from precipitated silica, dry pulverized silica, amorphous silica, fumed silica, friable silica, dispersible silica, alumina, talc, superabsorbent polymers, and fish bone meal between the ribs on at least one of the first side or the second side of the separator.

19. 10. A lead-acid battery comprising the lead-acid battery separator of claim 1, wherein the CMD ribs extend parallel to the top and bottom of the battery.

20. 18. A lead acid battery comprising the battery separator of claim 17, a lead-acid battery, wherein the CMD ribs extend parallel to the top and bottom of the battery, and the carbon is on the side of the separator facing the negative electrode of the battery.

21. A lead-acid battery comprising the battery separator of claim 1, a lead-acid battery, wherein the CMD ribs extend parallel to the top and bottom of the battery, and the silica is on the side of the separator facing the battery's positive electrode.

22. 22. The lead acid battery of any one of claims 19, 20, or 21, which is a flooded lead acid battery, including enhanced flooded batteries (EFB), starting, lighting, and ignition (SLI) batteries, and the like.

23. 22. The lead acid battery of claim 19, 20, or 21, including a thickening or gelling agent in the battery's electrolyte.

24. 22. A vehicle comprising the lead-acid battery of any one of claims 19, 20 and 21, wherein the lead-acid battery is a main lead-acid battery or an auxiliary lead-acid battery of the vehicle.

25. 25. The vehicle of claim 24, wherein the lead acid battery is the main lead acid battery.

26. 25. The vehicle of claim 24, wherein the lead acid battery is the auxiliary lead acid battery.

27. 25. The vehicle of claim 24, wherein the vehicle is a truck, a car, or an electric vehicle.

28. 1. A valve regulated lead acid (VRLA) battery comprising a composite battery separator including a valve regulated lead acid (VRLA) separator or an absorbent glass mat (AGM) separator and a polyolefin battery separator, wherein an outwardly facing side of the polyolefin battery separator comprises cross-machine direction (CMD) ribs extending parallel to the top and bottom of the battery.

29. 30. A vehicle comprising the VRLA battery of claim 28, wherein the VRLA battery is a main or auxiliary battery of the vehicle.

30. A lead-acid battery, two positive plates; a negative electrode plate between the two positive electrode plates; and a separator comprising a backweb and a first array of ribs extending from a first side of the backweb and a second array of ribs extending from a second side of the backweb, at least one of the first or second arrays of ribs comprising cross-machine direction (CMD) ribs; a lead-acid battery, wherein at least one side of the separator is coated with a siliceous material, and the separator encases the negative plates such that the CMD ribs face one or both of the positive plates and extend in a direction parallel to the top or bottom of the battery.

31. 31. The battery of claim 30, wherein the siliceous material is one or more selected from precipitated silica, dry pulverized silica, amorphous silica, fumed silica, crushed silica, dispersed silica, and colloidal silica.

32. A lead-acid battery, two positive plates; a negative electrode plate between the two positive electrode plates; a separator encasing both positive plates, the separator comprising: a backweb; a first array of ribs extending from a first side of the backweb; and a second array of ribs extending from a second side of the backweb, at least one of the first or second arrays of ribs comprising cross-machine direction (CMD) ribs, and at least one side of the separator being coated with a siliceous material; Equipped with A lead-acid battery, wherein the CMD rib faces the positive plate and extends in a direction parallel to the top or bottom of the battery.

33. 33. The battery of claim 32, wherein the siliceous material is one or more selected from precipitated silica, dry pulverized silica, amorphous silica, fumed silica, crushed silica, dispersed silica, and colloidal silica.

34. A lead-acid battery, at least one positive plate; at least one negative plate; a battery separator, wherein the profile of at least one side of the battery separator exhibits a surface area increase of 35% or more compared to a flat separator, and at least one side of the battery separator is coated with silica; A lead-acid battery comprising:

35. 35. The lead acid battery of claim 34, wherein the surface area increase is greater than 40%.

36. 35. The lead acid battery of claim 34, wherein the surface area increase is greater than 60%.

37. 35. The lead acid battery of claim 34, wherein the surface area increase is greater than 80%.

38. 35. The lead acid battery of claim 34, wherein both sides of the battery separator are coated with silica.

39. a polyolefin backweb; a silica coating on at least one side of the backweb; A lead-acid battery separator comprising:

40. 40. The separator of claim 39, wherein the backweb has a silica coating on both sides.

41. 40. The separator of claim 39, wherein the other side of the backweb has a carbon coating.

42. 40. The separator of claim 39, wherein at least one side of the backweb has ribs or protrusions.

43. 40. The separator of claim 39 having a backweb thickness of 10 to 500 microns.

44. 40. The separator of claim 39, wherein the overall separator thickness, including any ribs, is between 10 and 1200 microns.

45. 10. The lead acid battery separator of claim 1, wherein the backweb has a thickness of 8 microns to 500 microns, 10 microns to 500 microns, 50 microns to 400 microns, or 100 microns to 400 microns.

46. 46. The lead acid battery separator of claim 45, wherein the battery separator has an overall thickness of 8 to 1200 microns, 10 to 1200 microns, 50 to 1100 microns, or 600 to 1100 microns.

47. 10. The lead acid battery separator of claim 1, wherein the backweb has a thickness of about 100 microns to about 400 microns, 100 microns to 350 microns, 100 microns to 300 microns, 100 microns to 250 microns, 100 microns to 200 microns, or 100 microns to 150 microns.

48. 10. The lead acid battery separator of claim 1, wherein the battery separator has an overall thickness of about 500 microns to about 1100 microns, 500 microns to 1000 microns, 500 microns to 900 microns, 500 microns to 800 microns, 500 microns to 700 microns, 500 microns to 600 microns, or about 600 microns to 1000 microns.

49. a polyolefin backweb; a silica coating on at least one side of the backweb; A flat sheet or ribbed polyolefin membrane comprising:

50. 50. The flat sheet of claim 49, having a silica coating on both sides of the backweb.

51. 50. The flat sheet of claim 49, wherein the other side of the backweb has a carbon coating.

52. 50. The flat sheet of claim 49 having a backweb thickness of from 10 to 500 microns.

53. Improved separators for reducing stratification in lead-acid batteries, particularly flooded lead-acid batteries, reinforced flooded lead-acid batteries, or auxiliary lead-acid batteries, and / or improved separators, separator membranes, coated membranes, silica-coated polyolefin membranes, silica-coated and carbon-coated polyolefin membranes, flat-sheet membranes, ribbed membranes, and / or cmd-ribbed membranes, and / or improved batteries containing such improved separators, separator membranes, coated membranes, silica-coated polyolefin membranes, silica-coated and carbon-coated polyolefin membranes, flat-sheet membranes, ribbed membranes, and / or cmd-ribbed membranes, as shown and / or described herein.

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