MXPA00002186A - Glass fiber separators and batteries including such separators - Google Patents

Abstract

A lead acid battery (10) having a glass fiber separator (18) is disclosed. The separator material is a mass of intermeshed glass or other fibers produced by suspending the fibers in a gaseous medium, and collecting the suspended fibers on a foraminous material. The mass of the fibers suspended in the gaseous medium has a BET surface area of from 0.2 to 5.0 square meters per gram. A battery having a glass fiber separator material with added cellulose fibrils is also disclosed, as is a battery having a glass fiber separator with added particulate material such as silica.

Description

FIBERGLASS AND BATTERY SEPARATORS THAT INCLUDE SUCH SEPARATORS BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The present invention relates, in general, to the field of batteries or accumulators and, more specifically, to batteries in which separators containing glass fibers are placed between the positive and negative plates, and a method to produce such separators and batteries. As will be described later in greater detail, separators containing glass fibers are well known. However, long before the fiberglass separators, cedar veneers were used as a separating material, and were replaced by rubbery, microporous, hard separators and cellulose separators impregnated with resins.

DESCRIPTION OF THE PREVIOUS TECHNIQUE It is known the batteries or accumulators of regulated lead acid with valve ("sealed" - "recombinant") (VRLA); these usually consist of a plurality of positive and negative plates, as in a prismatic cell, or separator layers and positive and negative electrodes wound together, as in a "jelly roll" cell. The plates are arranged so that they alternate negative-positive-negative etc, with the separating material separating each plate from the adjacent plates. The separator, usually composed of a mat of glass fibers, is an inert material; This stores the acid in the battery and offers low electrical resistance. In addition, in VRLA batteries, the separating material offers innumerable gas channels between the plates through which the oxygen of the positive electrode can migrate, when generated there, to the negative electrode, where it can be recombined, with hydrogen, in accordance with the oxygen cycle. Another important function of a separator is that it exerts pressure against the paste of the plate or active material that forces the paste in contact with the plate and causes a pressure between the plates, guaranteeing that there is no interface in which corrosion may occur. The fiberglass separator material has been commercially produced by wet processes on papermaking equipment including Fourdrinier machines or wire endless belt and in extended wire rotoformers. In the production of the separator made of glass fibers for VRLA batteries, it is preferred that no organic binder is added to the raw materials from which the separator sheet is prepared; the entanglement of the individual fibers serves to keep the sheet in a cohesive structure, and the liquid sodium silicate or some of the different sulfate salts, which sometimes form on the surfaces of the fiber, serves as a binder. However, organic binders tend to decrease the capacity of a separator to serve as a table for the acid, and to decrease the amount of acid that a separator can contain. A large amount of work has been directed to modify the raw materials for the fiberglass from which the separators are produced to improve the operation of the battery and / or to reduce the cost of the separator. Some of the work has included the addition of synthetic fibers for various reasons, such as the use of thermoformable plastic fibers so that the separator can be heat sealed at its edges to wrap a plate. Another work, which pertains to the field of this invention, has been directed to the use of filler materials, for example, silica, to manufacture separators that are comparable with all fiberglass separators, at a lower cost. Separators made of glass fibers to which cellulose has been added, and polyolefin fibers to which cellulose has been added have also been suggested. The patents of the prior art are described below. U.S. Patent No. 4,465,748 (Harris) discloses glass fiber sheet material for use as a separator in an electrochemical cell, and prepared from 5 to 35% w / w of glass fibers of less than 1 μ in diameter; the patent also discloses a fiberglass sheet for such use wherein there are fibers of a continuous range of fiber diameters and lengths, and most of the fibers are no more than 5 mm in length. U.S. Patent No. 4,216,280 (Kono et al.,) Discloses glass fiber sheet material for use as a plate separator in a battery, and is prepared from 50 to 95% w / w of glass fibers of less of 1 μ of diameter and of 50 to 5% w / w of thicker glass fibers. The thicker glass fibers, the reference mentions, have a fiber diameter greater than 5 μ, preferably greater than 10 μ, and it is advantageous that some of the thicker fibers have diameters of 10 μ to 30 μ. U.S. Patent No. 4,205,122 (Minra et al.) Discloses a spacer for batteries of reduced electrical resistance, consisting of a mat of non-woven, self-supporting material consisting primarily of a mixture of olefin resin fiber having a thickness of 4 to 13 decirex and olefinic resin fibers having a thickness of less than 4 decigre, the last fibers being present in an amount of not less than 3 parts by weight per 100 parts by weight of the fibers; up to about 600 parts by weight of inert fillers per 100 parts by weight of the fibers can also be used. The battery separator is produced by subjecting a suitable aqueous dispersion to a sheet forming operation, drying the resulting nonwoven, wet mat and heat treating the dried mat at a temperature in the range of 20 ° C less than the melting point of the aforementioned fibers to a point approximately 50 ° C higher than the melting point. U.S. Patent No. 4,216,281 (O'Rell et al.) Discloses a separator material produced from a raw material containing 30 to 70 w / w synthetic polyolefin pulp, from 15 to 65% w / w of a siliceous filler and from 1 to 35% w / w of "long" fibers, which may be polyester fibers, glass fibers or a mixture of the two. Cellulose in an amount of up to about 10% w / w is described as an optional ingredient of the raw materials. U.S. Patent No. 4,363,856 (aterhouse) discloses a separator material prepared from a raw material composed of polyolefin pulp fibers and glass fibers, and mentions short polyester fibers, polyolefin short fibers and cellulose pulp fibers as alternative constituents of raw materials. U.S. Patent No. 4,387,144 (McCallum) discloses a battery separator having a low electrical resistance after prolonged use which is prepared by thermal consolidation and thermal stamping of a continuous paper material formed from raw materials containing synthetic pulp, the fibrils of which are filled with an inorganic filler, the continuous material incorporating a wetting agent which is preferably an organic sulfonate, and organic or phenolexotylated succinate. U.S. Patent No. 4,373,015 (Peters et al.) Discloses sheet material for use as a separator in a battery, and "containing organic polymer fibers", both examples of the reference discloses the sheet material as "forming a fiber polyester mat. short of approximately 0.3 mm in thickness ", and indicates that the polyester fibers are the range from about 1 μ to about 6 μ in diameter. Laminar separators for use in traditional batteries (not valve controlled) and containing glass fibers and organic fibers are described in all of the following U.S. Patent Nos. 4,529,677 (Bodendorf); No. 4,363,856 (Waterhouse); and No. 4,359,511 (Strzempko). U.S. Patent No. 4,367,271, Hasegawa, discloses storage battery separators composed of acrylic fibrils in an amount of up to about 10% w / w, and the difference of glass fibers. Japanese Patent Document 55 / 146,872 discloses a separating material containing glass fibers (50-85% W / W) and organic fibers (50/15% W / W). U.S. Patent No. 4,245,013, Clegg et al., Discloses a separator made by superposing a first sheet of fibrous material including polyethylene fibers with a second sheet of fibrous material including polyethylene and having a higher synthetic pulp content than the first sheet. U.S. Patent No. 4,908,282, Badger, discloses a separator consisting of a sheet prepared from the first fibers imparting to the sheet an absorbency of greater than 90% and of second fibers imparting to the sheet an absorbency of less than 80%, wherein the first and second fibers are present in such proportions that the sheet has an absorbency of from 75 to 95%. This patent discloses that fine glass fibers have a high absorbency, that thick glass fibers have a low absorbency, and that hydrophobic organic fibers have an extremely low absorbency, and that, when this separator is saturated with electrolyte, there remain hollows not filled with so that the gas can be transferred from plate to plate for recombination. Badger's description is incorporated herein by reference. U.S. Patent No. 5,901,275 (Brecht et al.) Discloses a glass fiber separator that extends when exposed to the electrolyte. The separator contains glass fibers that are impregnated with an aqueous solution of colloidal silica particles and a sulfate salt. The separator is produced by forming a coil of glass fiber papermaking, impregnating the coil with the aqueous mixture of silica and salt, slightly compressing the impregnated coil to remove some of the aqueous solution, partially drying the coil, compressing the coil, coil to a final thickness and complete the drying of the coil. The coil is preferably compressed to a thickness that is smaller than the distance between the plates in a given cell, and so that the insertion of a stack of cells assembled in a box is easy. When the electrolyte is added to the box, the salt dissolves in the electrolyte and the separator extends to provide good contact between the plates and the separators. According to the patent, silica contributes to the recombination function of the cells by incorporating the precompressed separator. The silica also contributes greatly to the stiffness of the separator, so that the separator can be characterized as rigid. It has been determined that the production of the separator for batteries by techniques of paper manufacture from a raw material of glass fibers and silica dust gives rise to problems that are caused by variations in the concentration of silica dust in raw materials . Common fiberglass raw materials have a liquid content that exceeds 98% w / w. During the manufacturing of the separator sheets, most of the water is removed from the raw materials at the first few feet of a screen in which the raw materials are emptied. The water, known as white water, is recycled and ends up in the headbox of the machine again. If the raw material is composed exclusively of glass fibers, almost none of the fibers passes through the wire and ends in the white or cast water. However, raw materials that contain fiberglass and silica dust are not doing so well. In the absence of a retention aid, significant amounts of the silica powder from these raw materials passes through the papermaking wire and ends in the white water. Doing this aside, this phenomenon causes the concentration of the silica powder in the raw material to increase, undesirably changing the properties thereof. Until now, the problem of silica dust and the like passing through a papermaking wire has been avoided with the use of binders and retention aids. U.S. Patent No. 2, 477,000 describes a paper of synthetic fibers produced from fibrils and fibers made by the methods where a solution of the fiber is extruded through very small holes (rows) and then the extruded solution is allowed to curdle or freeze in a bath of precipitation or by evaporation of the solvent or by changes in temperature (see column 2, lines 25 et seq.). The patent mentions that the fibers of cellulose acetate, cellulose nitrate, viscose regenerated cellulose, "Vinilite" (a synthetic resin prepared by polymerization of vinyl compounds), Aralac (a fibrous product made from skimmed milk casein) and spinning glass "with a length range of up to one inch and diameter from 12-80 μ, and preferably fibrils obtained from flax, Manila hemp, hemp or hemp can be used to manufacture the paper. fibrils should be from 0.0015 to 0.0025 inches in length and from 0.0000027 to 0.0000044 inches in width, WO 98/12759, an International Application published on March 26, 1998, describes "a mat of resilient fibers, preferably manufactured from microfibers adapted especially for use as a battery separator for underfed electrolyte batteries .... The fibrous mat, with one or two surface layers, can be formed from and a fibrous layer exposed to air by subjecting one or both surfaces of the layer to hydroentanglement to increase the entanglement of the fibers in and adjacent to the main surface (s) relative to the entanglement of the fibers in the Resilient fibrous layer. The fibrous mat with a practically uniform density can be prepared by flooding the layer with a liquid and vacuuming through the layer. "A publication (apparently, European Patent Application 98-15, from Japan Vilene Co., Ltd, filed on September 29, 1997 as application 97116846) shows the kind of entanglement described in WO 98/12759 to produce the material of Figures 1 and 2 thereof, but applied to the entire body of the separator material instead of a zone or zones adjacent to one or both of the major surfaces as in WO 98/12759 An English-language summary of a published Japanese Patent Application (07147154 published June 6, 1995) entitled SEPARATOR FOR ALKALINE BATTERY states: "A fiber having a transverse shape shown in (c) of the drawing, for example, is comprised of 0.04 to 0.12 deniers of circular polypropylene component and petal, 2 and 0.12 denier of a polyethylene component 1. 100% This composite fiber divider with a fineness of 2 denier and a fiber length of 38 mm is opened by a card machine for unidirectional lamination and cross fiber coils with METSUKE of 1.3 and 52 f / m2. This is treated on both surfaces with a water flow having a water pressure of 130 kg / cm2 on a nozzle plate having a nozzle diameter of 0.13 mm and a distance of 0.6 mm. This cloth is immersed in fuming sulfuric acid, sulphonated and then pressed to provide a separator having a METSUKE of 65 g / m2 and a thickness of 0.15 mm. The same treatment can be carried out in different constitutions of (c) in the drawing. Thus, excellent electrolyte resistance, oxidant property and liquid holding property are provided, and a battery can be operated quietly for a long period. " BRIEF DESCRIPTION OF THE INVENTION PRESENT The present invention is based on the discovery of a non-binder fiberglass mat suitable for use as a separator for valve-controlled lead acid batteries ("sealed" - "recombinant"). VRLA can be produced with a dry process by collecting fibers from the fiber forming apparatus, without subjecting them to a wet paper manufacturing process or other subsequent forming process. For example, the glass fibers produced by the flame-blowing process, which is described in more detail below, can be rolled up in a drum until a mat weighing approximately 1,000 grams per square meter has been collected; the mat can then be divided transversely, and separated from the drum as sheets weighing approximately 1,000 grams per square meter, having a dimension that equals the circumference of the drum, and one that equals the width of the drum. This mat, which, in a common example, has an average fiber diameter of 0.8 μ can then be separated into layers having the weight in grams per square meter desired in a given battery separator, and the layers can be cut to size and used as separators, as will be described later in greater detail. The continuous material having the determined grammage can also be taken directly from the drum or the glass can be reduced to fibers by another method which is controlled so as to produce a continuous sheet having the determined grammage. A mat of glass fibers that can be used in the practice of the present invention can also be prepared by what is known as a "rotating process" in a glass forming apparatus that includes a tank to melt the glass, a centrifugal rotating sleeve fast with small holes in a periphery, at least one high pressure hot gas nozzle from which a high speed fiber forming jet is directed through the periphery of the centrifuge, and a collecting conveyor. The molten glass fed to the centrifugal sleeve is caused to flow by centrifugal force through the peripheral holes of the sleeve in the fiber-forming jet, whereby the glass streams are attenuated and carried to a gas-impermeable collector conveyor. The mat of this process can also be collected in a drum, divided transversely and separated from the drum as sheets which, again, can weigh approximately 1,000 grams per square meter, and can be composed of fine fibers, fibers of average diameter 0.8 μ when the process Rotary is that of U.S. Patent No. 5,076,826, or may be in the range of about 3 μ when another rotary process is used. This mat can also be separated into layers having the weight in grams per square meter desired in a given battery separator, and the layers can be cut to size and used as spacers, as will be described later in greater detail. This coil having the determined grammage can also be taken directly from the drum. It has been found, by examinations using an electron scanning microscope, of the mat produced as described in the two previous paragraphs and collected in a drum, that the mat is formed in small layers, each of which is composed of fibers deposited during a revolution of the collecting drum, and that there is a fiber diameter gradient within each of the discrete layers, the smaller diameter fibers being concentrated adjacent to a major surface of each layer, and the larger diameter fibers being concentrated next to the other main surface. A part of the increased resilience of the battery separator according to the invention is attributed to the observed layering, and another part is attributed to the gradient in the diameter of the fibers within each layer. It will be appreciated that the release material can also be produced by a wet papermaking process where similar layering occurs, for example, by emptying a plurality of slurries of glass fibers or other fibers, the first into the screen of the apparatus. paper manufacturer and the second and subsequent ones on the previously emptied fibers, or assembled a plurality of thin sheets of glass or other fibers prepared by a wet process to produce a composite separator having the desired thickness and grammage. Accordingly, in one aspect, the invention is a battery separator composed of a plurality of thin sheets of nonwoven fabric assembled to form the separator, and the thin sheets can be manufactured by a process of exposure to air or wet. The thinner sheets of the glass fiber mat can also be produced by the flame blowing process or by the rotating process, including that of U.S. Patent No. 5,076,826 and many of the thinner sheets to provide the desired basis weight , which is usually in the range from about 20 to about 1000 g.irf can be stacked and then cut to size. To produce thinner sheets, glass fibers can be produced from softened glass and harvested in a conventional manner, usually on a foraminous conveyor and the speeds of the fiber-forming process and the conveyor can be established so that a mat having the desired grammage is transported from the forming operation and rolled up for future use, or cut to size, in which case it can be used immediately to produce batteries, or stacked for future use. The continuous sheet can also be collected with a cross tracer to improve its uniformity. When a battery is produced, at least one stack of alternating positive and negative plates is assembled, with a separator between adjacent plates, and the separator of each cell is compressed so that the cell can be slipped into a sac that is a part of the cell. the battery case. It is important that the separator has sufficient resilience, after such compression, that it exerts the necessary pressure against the paste or active material in each plate to force the paste in contact with the plate, and to make pressure between the plates, guaranteeing that there is an interface , along the faces of the plates, between the paste of the plate or active material, the electrolyte and the oxygen. A normal test has been developed to measure the resilience of a separator material. The results of this test, as will be explained below in greater detail, indicate that the battery separators according to the invention are significantly more resilient than the otherwise identical separators prepared from different samples of the same glass fibers, but by a traditional wet papermaking process.

OBJECTS OF THE INVENTION Therefore, an object of the present invention is to provide an improved VRLA battery or another containing a separator composed, at least mainly, of glass fibers as collected from a fiber-forming process, ie, without have been subjected to a wet paper manufacturing process or to a post-training process such as what is called "exposed to air" or spinning, or another secondary process subsequent to the formation. Another object is to provide a method for producing a battery separator composed mainly of glass fibers. Still another object is to provide a VRLA separator of glass fibers having better resilience than a separator prepared by the wet paper manufacturing process of the same fibers. Still another object is to provide a VRLA battery separator of glass fibers having greater resilience, compared to previously known separators and, as a consequence, it may be from 10 to 50% lighter in weight per unit area (grammage) but still provide the same "BCI" (Battery Council International) thickness as the traditional wet-laid separator, ie, 300 grams per square meter for the separator having a BCI thickness of 2.13 millimeters. Still another object is to provide a VRLA battery separator that has better resilience and shock absorbing properties because it is composed of a plurality of separate layers. Another objective is to provide a fiberglass VRLA separator having greater absorbency for a battery electrolyte compared to a separator made by the wet paper manufacturing process of the same fibers. Still another objective is to provide a VRLA separator material of glass fibers in which the average length of the fibers is longer than in a separator made by the wet paper manufacturing process from the same fibers because no breakage occurs. of the fibers associated with the papermaking process or formation and re-dispersion after formation. Yet another object is to provide a separator that is composed of multiple layers formed separately from glass fibers or other fibers. Other objects and advantages will be apparent from the following description, with reference to the attached drawings.

DEFINITIONS As used herein, the term "percent v / v" means percent by volume, the term "percent p / p" and the symbol "%" mean percent by weight, the term "wire" , as applied to a papermaking machine, means the surface of the machine on which the raw material is emptied in the production of the paper, and can be, for example, the sieve of a Fourdrinier machine or the vacuum drum of a rotoform machine; the pore sizes reported herein, unless otherwise indicated, are in microns, and are determined by the first bubble method or by liquid porosimetry, Coulter; all temperatures are in degrees C; and the following abbreviations have the meanings indicated: μ = microns or microns; mg = milligram or milligrams; g = gram or grams; kg = kilogram or kilograms; 1 liter or liters; ml = milliliter or milliliters; ce = cubic centimeter or cubic centimeters; pcf = pounds per cubic foot or pounds per cubic foot; m = meter or meters; cm centimeter or centimeters; mm = millimeter or millimeters; thousand = inch by 10 -3 or inches inch by 10-3 (multiply by 25.4 to convert to mm); kPa = pressure in thousands of Newtons per square meter; psi = pounds per square inch (multiply by 6.89 to convert to kPa, and kN = force in thousands of Newtons.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view with separate parts to show the details of the construction of a VRLA battery according to the invention. Figures 2 and 2a are vertical sectional views showing different parts of the apparatus for producing a fiberglass mat for what is called a "rotary process" that can be used as it is collected from the fiber-forming process, ie without having to undergo a wet papermaking process to produce a battery according to the invention; together Figures 2 and 2a constitute a schematic representation of the apparatus. Figure 3 is a schematic representation similar to a part of the apparatus of Figure 2a, showing the different apparatus that can be used to produce a fiberglass mat for what is called a "flame blow" process; the apparatus of Figure 3 can be used only to produce a mat or with the apparatus of Figure 2 to produce a fiberglass mat that can be used as it is harvested from the fiber formation process to produce a battery in accordance with the invention; Figure 4 is a schematic representation similar to Figure 3 of yet another apparatus that can be used with that of Figure 2 to produce a mat of glass fibers that can be used as it is harvested from the fiber-forming process to produce a battery according to the invention. Figures 5 and 7 are graphs of thicknesses in mm of the separator materials that can be used in batteries according to the invention, when compressed (the compression curve) vs the force in kPa applied to compress the separator to this thickness and the rebound thickness in mm (the rebound curve), vs the force applied before the rebound thickness was determined. Figures 6 and 8 are graphs of the data represented in Figures 5 and 7 and, in addition, graphs of the thickness of a glass fiber separator placed in wet in mm when compressed vs. the force in kPa applied to compress the separator to this thickness and the rebound thickness in mm vs. the force applied before the rebound thickness was determined for commercial separator materials that have been used in batteries. Figure 9 is a graph of the thickness of the separator in mm against the compression force in kPa for each of the two different materials under compression, and the rebound thickness for each of the same two materials after they are recovered afterwards. of being downloaded. Figure 10 is a view of a vertical section showing, as a diagram, the apparatus similar to that of Figure 3 to produce a mat of glass fibers for what is called "method of blowing the flame" which can be used as it is collected from the fiber-forming process, ie, without having been subjected to a papermaking process, wet to produce a battery according to the invention.

DECRIPTION OF THE PREFERRED MODALITIES A single-cell battery according to the invention, with a total of 9 plates is indicated generally in 10 in Figure 1. Except for the identity of the separating material therein, the battery 10 is conventional; The separator can be used in other conventional batteries. The battery 10 contains 4 positive plates 11 which are electrically connected to a positive terminal 12 and 5 negative plates 13 electrically connected to a negative terminal 14. The plates 11 and 13 are housed inside a battery case 15 which is covered by a upper part 16. There is a hole through a shoulder 17 in the upper part 16 of the battery. The separators 18 are composed of sheets of spacer material wrapped around the bottom and both main faces of each positive plate 11. In a specific example, 5 batteries 8A-U1 similar to batteries 10, but having 4 negative and 4 positive plates were produced from the separating material composed of the collected glass fibers, as the fibers were formed, on a mat weighing about 310 g / m; the fibers had an average diameter of substantially 0.8 μ. It was also produced a battery of ¿t control using a separator that is available commercially under the denomination BG 30005; This material, which is manufactured by the wet paper manufacturing process, weighs 300 +/- 15 gm2. This control was developed so that the assembly and the properties of the five 8A-U1 batteries could be compared with the assembly and the properties of a control prepared with the separator having the same general objective grammage. It was observed that the dry-laid separator used to produce the five batteries had a thickness and resiliency substantially greater than the control separator; this confirmed the findings in the laboratory related to the separator placed in dry. A montage of three pairs of positive and negative plates with the separator placed dry had approximately the same thickness as a five-pair assembly of positive and negative plates with the separator BG 30005, indicating that the separator placed dry for a given battery should have approximately three fifths of the weight of the separator placed in conventional wet for this battery. Difficulties were found in the assembly of the batteries by the separator placed in dry due to the high resilience of the separator exposed to the air. These difficulties arise when attempts are made to empty short fibers onto the assemblies of the plates with separators and when inserting the plate assemblies and separators into the batteries. The boxes of the batteries that were prepared were deformed by forces exerted by the separator. A dry plate and separator assembly was compressed in a press with a ton of force for 15 minutes; since the surfaces of the plates were 4.85 inches by 4.85 inches, this represented an applied force of about 87 psi. This assembly was then inserted into a battery box, which did not deform. In another example, an outer wrapper of separator was removed and batteries similar to batteries 10, but having 4 positive plates and 4 negative plates were assembled from the remainder of the separator, which had a grammage of about 250 g / cm. The batteries had cyclic operating characteristics substantially equivalent to those of the control battery. In another specific example, a glass fiber mat weighing 1000 g / m was produced and was composed of fibers having an average diameter substantially of 0.8 μ; a layer weighing 318 g / m, which was separated from this mat, is the separator in the battery described earlier in this paragraph. The separator was subjected to "compression" and "rebound". The thickness of the compression was determined by the method described in U.S. Patent No. 5,336,275 under various applied loads, and then the excess of each load applied above 3.79 kPa was released.; the first measurements are the thicknesses by "compression" while the last ones are thicknesses by "bounce". The average results are presented graphically in Figure 5, which is a graph of the thicknesses of the separator 18 in mm (designated A) at different loads applied in kPa and of the thicknesses in mm (designated B) after it was released. excess above 3.79 kPa of each applied load. Each data point for one of the curves in Figure 5 is indicated by "+" (this is the curve for the "bounce" thickness) and each data point for the other curve is indicated by a point (this is the curve for "compression" thicknesses). The data plotted in Figure 5 indicate that the separator is a protruding material. The compression and rebound thicknesses were determined for a commercially available separator material that is produced by a wet process using the papermaking equipment. The tested material is available with the commercial designation HOVOSORB BG 30005, grammage 318 g / m. The average results of this test are presented graphically in Figure 6, which is a graph similar to Figure 5, showing the data plotted in Figure 5 and the designated compression thicknesses C) of the HOVOSORB separator BG 30005 in mm and the bounce thickness mm (designated D) against the load applied in kPa. In yet another specific example, a glass fiber mat weighing 1000 g / m was produced and was composed of fibers having an average diameter of substantially 0.8 μ; a layer weighing 130 g / m, which was separated from this mat, has been used as the separator in the battery 10. The separator was subjected to "compression" and "rebound" tests. The average results are presented graphically in Figure 7, which is a graph of the compression thicknesses of the separator in mm (designated E) and the rebound thicknesses in mm (designated F) against the load applied in kPa. The data points for one of the curves in Figure 7 are shown by more marks (these are the data points for the "bounce" curve), while those of the other curve are indicated by dots (these are for the "compression" curve). The data plotted in Figure 7 indicates that the separator is a protruding material. The compression and rebound thicknesses were determined for another separating material that is available commercially, under the trade designation BGC 140, grammage 130 g / m. The average results of the BGC 140 material are also presented graphically in Figure 9, which includes a graph of the compression thicknesses of the BGC 140 separator in mm (designated G) and the rebound thicknesses in mm (designated H) against the load 26 applied in kPa. The data points for one of the BGC 140 curves are shown by clear circles (these are the data points for the "bounce" curve), while one * indicates each data point for the other BGC 140 (these are the "compression" curves). The compression and rebound tests of other separating materials composed of the 608 mf mat with a range in the grammage from 130 to 1151 g / m, indicated that these are all outstanding separating materials. In another example, a fiberglass mat weighing 258 g / m was produced and was composed of fibers having an average diameter of substantially 0.8 μ. This separator was subjected to "compression" and "rebound" tests. The average results are presented graphically in Figure 9, which is a graph of the separator compression thickness in mm and the rebound thickness in mm against the applied load in kPa. The data points for one of the curves in Figure 9 (designated I) are the data points for the "bounce" curve, while those for the other curve (designated J) are for the "compression" curve) . The compression and rebound thicknesses were also determined for a wet-laid separating material, grammage 224 g / m. The average results of the wet-laid separator material are also presented graphically in Figure 9, showing the compression thicknesses of the wet-laid separator in mm (designated K) and the rebound thicknesses in mm (designated L) against the applied load in kPa. It has been considered desirable that the glass fiber separator material used in the VRLA batteries contain a substantial proportion of fine fibers, for example, finer than about 5 μ. The separators, if they contain a sufficient proportion of fine fibers, are able to contain enough of the relatively small amount of electrolytes that are used in these batteries, to make contact with the plates, and allow an electric current to flow through the separators. . It is usually desirable that the spacers also contain a substantial proportion of thicker fibers to impart strength and, also, reduce the cost per pound. The finest glass fibers currently known have been produced by the flame blowing process, for example, which are shown in Figures 2 and 2a, appended, and described herein by reference thereto. This is the method by which the glass fiber mats from which the separating material for the battery 10 was separated, as already described. Accordingly, the flame-blowing process has been used to produce the spacer material for a battery according to the invention. The process of blowing to the flame, as is known, if variables such as the temperature and velocity of the hot gas burst that attenuates the glass filaments that are extracted from a melting tank are suitably varied, can also be used to produce fibers that are thicker or finer than 0.8 μ in diameter. The apparatus shown in Figures 3 and 10 also produces glass fibers by the process of blowing to the flame, but produces fibers somewhat thicker than those in Figures 2 and 2a. The dry-laid mat, produced as already described, has been examined under an electronic scanning microscope. It was observed that the material that was collected on a drum while this drum rotated more than one revolution was composed of a plurality of discrete layers, one for each rotation of the drum during the collection process and that had a gradient of the diameter of the fibers within each of the discontinuous layers, the fibers of smaller diameter being concentrated next to a main surface of each layer, and the fibers of larger diameter being concentrated next to another main surface. The tests described in the above show that this separator material has better resilience, compared to the wet-laid separator. An experiment that has been carried out with a plurality of wet fiberglass separator sheets demonstrates that the discontinuous layer composite separator also has better impact resistance compared to the traditional wet laid separator. The experiment included the compression of a stack of wet-laid separator sheets using a compression fitting on a conventional tensile testing machine. Examination under the scanning electron microscope of the compressed material revealed that virtually all the deformation occurred on one of the outer sheets of the stack. This indicates that the layered separating material would also have a better impact resistance compared to the material that is practically uniform throughout its thickness. It will be appreciated that the separating material can also be produced by a wet papermaking process where similar layering occurs, for example, by emptying a plurality of slurries of glass fibers or other fibers, the first on the screen of the manufacturing apparatus of paper and the second and subsequent on freshly emptied fibers, or assembling a plurality of thin layers of glass fibers or other fibers made by a conventional wet process to produce a composite separator having the desired thickness and grammage. It will also be appreciated that the dry-laid coils of the fibers prepared by the process described in Chapter 7: Dry-Placed Systems by Albin F. Turbak, "Non-Woven Genres: Theory, Process, Operation and Testing" can also be used as separator material in batteries according to the present invention. This process includes carding bundles of fibers that can be purchased from manufacturers, and suspending the carded fibers in air or other gases within a hood, and using vacuum to carry the fibers suspended on a foraminous conveyor so that they form a continuous material or bovine of a desired thickness. Figures 2 and 2a show the apparatus that can be used to produce the battery separating material composed of the first glass fiber having a first average fiber diameter and the second glass fibers having a second average fiber diameter. The apparatus has two different fibrizers, one of which is indicated in general in 19, and the other of which is indicated in general in 19 '. The two fibrizers 19 and 19 'are identical; each includes a spinning unit 20, 20 'made by a rotary spindle 21, 21' which can be rotated at high speed about its longitudinal axis 22, 22 'by a motor (not illustrated) that drives a pulley driven by belt 23, 23 'which is secured to the upper end of the spindle 21, 21'. Each of the spinning units 20, 20 'includes an internal bowl 24, 24' rotating with the spindle 21, 21 '. Each bowl 24, 24 'has a peripheral wall 25, 25' through which there are some holes of small diameter 26, 26 '.

Each spinning unit 20, 20 'also has a heat insulating jacket 27, 27' which minimizes the heat loss of the bowl 24, 24 '. As each of the spinning units 20, 20 'rotates, the molten glass 28, 28' flows from a melting tank (not illustrated) through a pipe 29, 29 'to one of the bowls 24, 24 'from which the centrifugal force causes glass streams to flow through the holes 26, 26'. An annular nozzle 30, 30 'surrounds each of the spinning units 20, 20'. The combustion of a fuel gas in a chamber 31, 31 'pushes a jet of heated gas to flow down through the nozzles , 30 '. The jets of gas flowing from the nozzles 30, 'attenuate the molten glass streams flowing through the holes 26, 26' in fine fibers 32, 32 'and direct them downwards on a conveyor 33, 33' where they are collected as a mat. Each fiberizer 19 and 19 'also include a riser 34, 34' which is connected to a source for compressed air (not shown) and to an end tube 35, 35 'extending vertically upwards, and ends just below the thermal protectors 27, 27 '. As indicated by the arrows 36, 36 ', the air flows in the veils of the fiber 37, 37'. The patent also discloses that the fibrizers, except for the parts thereof that cause upward air flow, were prior art. The apparatus of Figures 2 and 2a can be operated to produce the spacer material for use in batteries according to the invention. For example, the fibbers 19 and 19 'can be operated to produce fibers having an average diameter of 0.8 microns, in which case the speed of the conveyors 33 and 33' can be controlled so that the mat 38 having the desired grammage is accumulated on the conveyors before being transported from inside the housing 39 'to send it towards a conveyor tilted upwards 40 and collected on a pick-up roller 41. finally, the mat 38 can be divided in width and used, for example, as described in U.S. Patent No. 5,344,466 to produce batteries. Otherwise, the fiberizer 19 can be operated to produce fibers with an average diameter of 0.8 microns, and the fiberizer 19 'can be operated to produce fibers with a larger fiber diameter, namely 1.5 microns, and the speed of the fibers. conveyors 33 and 33 'can be controlled to provide a mat with a desired grammage and a desired fiber content of the two diameters. Since it is usually desirable that finer fibers of a separator be adjacent to the plates of a battery, the two layers of the separator described in this paragraph can be placed one on top of the other, with their sides of the fiber coarser together. to the other, to provide a particularly advantageous separating material. Another apparatus (not illustrated) that can also be used to produce the separating material composed of two outer layers of fine fibers and a central layer of thick fibers consists of the apparatus of Figures 2 and 2a plus a third fiberizer, identical to the Fibers 19 and 19 'which are placed between the two so that it deposits the fibers on a mat that has already been formed in the fiberizer 19 and the fiberizer 19' deposits the fibers in the mat discharged by the third fiberizer. In this case, the fiberizers 19 and 19 'are preferably operated to produce fine fibers, and the third fiberizer is operated to produce thicker fibers. With reference to Figure 3, still another apparatus that can be used in the production of the separator material that is used in a battery according to the invention is indicated in general at 42. The apparatus 42 consists of a fiber collection area 43 wherein primary filaments 44 entrained by traction rollers 45 from a fiber-forming sleeve 46 in a glass melting tank 47 pass over a filament holder 48 and a burst of hot gases from a high pressure hot gas nozzle 49 The burst of hot gas softens the filaments, thinning them into fine fibers 50 and projecting them towards the right side of the collection area 43. As indicated by the arrows 51, atmospheric air can enter the region where the fibers 50 are projected. The glass fiber mat 52, which may be the one discharged from the fiberizer 19 enters the collection area 43 on a conveyor 53, which passes over a suction box 54, keeping the mat 52 in contact with the conveyor 53 and dragging the fibers 50 to the bottom of the collection area 43 and on the mat 52 and a mat 55 that is formed within the collection area as the fibers 50 are deposited, first, on the mat 52, and then on the fibers 50 that have been deposited previously. The mat 55 can be transported to the fibrillator 19 'for augmentation, or it can be divided, stacked and used as already described to produce a battery according to the invention, or it can be rolled up for further processing.

With reference to Figure 4, still another apparatus that can be used in the production of the spacer material that is used in a battery according to the invention, is generally indicated at 56. The apparatus 56 contains a fiber collection area 57 in which a strand 58 of textile glass fibers is pulled by traction rollers 59 to draw individual fibers 60 from a sleeve of textile fibers (not illustrated) into a glass melting tank (not illustrated), through a collecting shoe 61 to a second driving roller 62 by means of which it is directed to a gas burst coming from a high pressure gas nozzle 63. The gas burst breaks the strand 58 and projects the fibers 60 towards the inside of the right the collection area 57. A mat of glass fibers 63, which may be the one discharged from the fiberizer 19, enters the collection area 57 on a conveyor 64, which passes over a suction box 65, having the mat 63 in contact with the conveyor 64, and dragging the fibers 60 to the lower part of the collection area 57 and on the mat 63 and a mat 66 that is formed within the collection area as the fibers are deposited. first, on the mat 63, and then on the fibers 60 that have been previously deposited. The mat 66 can be transported to the fiberizer 19 'for its augmentation, or it can be divided, stacked and used as already described to produce a battery according to the invention, or it can be wound on a roller for further processing. The apparatus of Figures 2 and 2a can also be used to produce a multilayer separator material, for example, by operating the fiberizing apparatus 19 of Figure 2 to deposit a mat composed of a thin layer of fine fibers on the conveyor 33, advancing this thin layer of mat towards the fibrillating apparatus of Figure 2a and depositing additional fibers and silica on top of the thin layer of the mat. The fibers can be deposited in the apparatus of Figure 2a as already described, and an aqueous silica slurry can be fed at a suitable speed to a rotary plate 67 with veins 68 so that the slurry is thrown out by force centrifuge in the plate 67 and then projected radially outwardly by the veins 68 in the veil 37. Any amount of the slurry falling on the thin layer of the mat on the conveyor 33 'is simply collected there, becoming part of the separator material in accordance with collides on the veil 37. In the same manner, the apparatus of Figures 2 and 2a can be used to produce yet another multi-layer separator material, for example, by operating the fiberising apparatus 19 of Figure 2 to deposit a composite mat of fine fibers on the conveyor 33, advancing this layer of the mat in the fibrillating apparatus of Figure 2a and depositing additional fibers and a slurry Concentrated by extremely fine cellulose fibrils in the upper part of the mat layer. The fibers can be deposited in the apparatus of Figure 2a as already described, and an aqueous slurry of the cellulose fibrils can be fed at a suitable speed to a spinning plate 67 with veins 68 so that the slurry is thrown outwardly. by the centrifugal force in the plate 67 and then projected radially outwards (as indicated in 70) by the veins 68 in the veil 37. Any amount of the slurry falling on the thin layer of the mat on the conveyor 33 will simply be collected there, a portion of the spacer material becoming just like this collision on the veil 37. There may also be a plate 67 (not illustrated) in the fibrizer 19 of Figure 2, which may be operated just as described to introduce the cellulose fibrils in the fibers formed in the fiberizer 19. Now in relation to Figure 10, the apparatus generally indicated at 69 is similar to that of Figure 3, except that a drum collector 70 has been replaced by the conveyor 53 of the apparatus of Figure 3. The apparatus 69 comprises a fiber collection area 71 on the which filaments 44 entrained by the traction rollers 45 from a fiber-forming sleeve 46 in a glass melt tank 47 pass over a filament holder 48 and into a burst of hot gases from a hot gas nozzle at high pressure 49 The burst of hot gases softens the filaments, thins them into fine fibers 50 and projects them towards the inside of the collection area 43. As indicated by the arrows 51, the atmospheric air can enter the region where the fibers 50. A mat 72 that is collected on a foraminous surface 73 of the drum 70 is separated from the drum by a roller 74 from which it is sent to a collection area, not shown . It will be appreciated that the present invention, as described above, may be subjected to various modifications without departing from the spirit of the invention described and claimed herein. For example, the separator according to the invention and composed of a plurality of sheets or layers can be sewn to provide additional physical integrity for the separator. In addition, or otherwise, the layers of material may be overlapped, crossed. In addition, it is possible to incorporate additives that do not affect the essential characteristics of the separator.

Claims (61)

1. A storage battery consisting of a plurality of lead plates in a closed box, a separator of fibrous sheet plates between the adjacent plates, and a body of a sulfuric acid electrolyte absorbed by each of the separators and kept in contact with given one of the adjacent plates, the improvement of the separator sheets composed mainly of glass microfibers, with the conditions of: (a) that the glass microfibers have a BET surface area from 0.2 to 5 m2 per gram, ( b) that the separator has not been flooded or subjected to crystallization in needles or hydroentangling, and (c) that the fibers of the sheet have not received the slurry of a liquid.

2. A glass fiber separating material which is a mass of interlaced glass fibers produced by suspending the glass fibers in a gaseous medium, by spraying an aqueous slurry containing from 0.2 percent w / w to 20 percent w / w fibril. cellulose, based on the weight of the glass fibers and the cellulose fibrils, in contact with the suspended glass fibers, the fibrils being of a slurry having a Canadian refining sufficiently low that the separating material has a higher tensile strength that an otherwise identical separator where the glass fibers, having an average diameter greater than one replaces the cellulose fibers, and collecting the suspended glass fibers and the cellulose fibrils on a foraminous material, with the proviso that the mass of the suspended and harvested glass fibers have a BET surface area from 0.2 to 5 m2 per gram.

3. A fiberglass separator material as recited in claim 2, wherein the cellulose fibrils are impregnated with a synthetic, solidified latex.

4. The fiberglass separator material as recited in claim 2, wherein the cellulose fibrils are from a slurry having a Canadian refining no greater than 100 ce.

The fiberglass separator material as recited in claim 2, wherein the cellulose fibrils adjacent to one of the two opposite major surfaces are impregnated with a synthetic latex, solidified, while the cellulose fibrils adjacent to the another of the two opposite major surfaces are not impregnated.

6. A multi-layered sheet useful as a separator in a valve-controlled lead acid battery, the sheet consisting of at least one first layer and a second layer, the sheet being produced by the method consisting of the steps of: forming the first layer by suspending the glass fibers in a gaseous medium, collecting a mat of the glass fibers on a foraminous material, and forming the second layer by suspending the glass fibers and a powder that is inert to the reactions of the battery in a gaseous medium, collecting the glass fibers and the powder on the first layer, the powder having an average particle size in the range from 0.001 microns to 20 microns, the first layer having a pore size small enough that practically all the powder It has been collected in the first layer and remains in the multilayer sheet, with the proviso that the BET surface area of the 2 fibers in the multiple sheet It's layers are from 0.2 to 5 m per gram.

7. The multilayer sheet as recited in claim 6, wherein the first layer has a grammage less than 50 g / m.

8. The multilayer sheet as recited in claim 6, which further includes a third layer, and wherein the third layer was formed by suspending glass fibers in a gaseous medium, and collecting the suspended glass fibers as the third layer. layer in the first and second layers while these are supported on a foraminous material.

9. A VRLA battery consisting of a boxhaving negative and positive alternating plates in the box, positive and negative terminals, adequate electrical connections between the plates and the terminals, and separating material between the negative and positive alternating plates, i.e., a multi-layer sheet as mentioned in FIG. claim 6.

10. The VRLA battery consisting of a box, having positive and negative plates alternating in the box, positive and negative terminals, adequate electrical connections between the plates and terminals, and the separating material between the positive and negative alternating plates, that is, the multiple box sheet as mentioned in claim 6, and has a minimum nitrogen BET surface area [sic] of at least 1.1 m / g.

The multilayer sheet as recited in claim 6, wherein the first layer has a minimum nitrogen BET surface area of at least 1.6 m / g.

12. The multilayer sheet as mentioned in claim 6, wherein the second layer contains at least 50% particulate silica powder, based on the weight of the fibers and silica powder in the second layer.

The multilayer sheet as recited in claim 6, wherein the second layer contains at least 70% particulate silica powder, based on the weight of the fibers, and silica powder in the second layer.

14. A glass fiber separator material consisting of a mass of interlaced glass fibers substantially all of which has a fiber diameter not greater than about 15 microns, and at least 5% w / w of which has a fiber diameter less than one miera and, distributed through the glass fibers, from 0.2% w / w to 20% w / w of cellulose fibrils of a slurry having a Canadian refining sufficiently low that a battery made with the separator has a shelf life of service, when cycled, at least 10% greater than an otherwise identical separator, where the fiber having an average diameter greater than 1 miera replaces the cellulose fibrils, the separator having been produced by suspending the glass fibers and 0.2% p / pa 20% w / w of cellulose fibrils, based on the weight of the glass fibers and the cellulose fibrils, in a gaseous medium, and collecting the glass fibers suspended in a fiber material. aminoso

15. A sealed acid / sulfuric acid recombinant storage battery consisting of a plurality of lead plates and a closed box, a fibrous sheet plate separator as mentioned in claim 14 between the adjacent plates, and a body of an electrolyte of sulfuric acid absorbed by each of the separators and kept in contact with each of the adjacent plates.

16. In a storage battery consisting of a plurality of lead plates in a closed box, the fibrous sheet plate separator between the adjacent plates, and a sulfuric acid electrolyte body absorbed by each of the separators and held in contact with each of the adjacent plates, the improvement of a glass fiber separating material produced by suspending the first glass fibers having an average fiber diameter determined in a gaseous medium, collecting the first glass fibers suspended on a foraminous material, suspending the second glass fibers having an average fiber diameter different from the first average diameter determined in a gaseous medium, and collecting the second glass fibers suspended on the first collected glass fibers, with the conditions of: (a) that the mass of the interlaced glass fibers have a BET surface area from 0.2 to 5 m per gram or (b) that the separator has not been flooded or subjected to crystallization or hydroentangling, and (c) that the fibers of the sheet have not been lacquered with a liquid.

17. The glass fiber separator material as recited in claim 16 wherein the first glass fibers and the second glass fibers have substantially the same chemical composition.

18. In a storage battery as recited in claim 1, the improvement wherein the individual interlaced fibers are bonded to the adjacent fibers at contact points by an inorganic binder.

19. In a storage battery as recited in claim 1, the improvement wherein the individual interlaced fibers are bonded to the adjacent fibers at contact points by an organic binder.

20. In a storage battery as mentioned in claim 1, the improvement wherein the separator sheet consists mainly of interlaced glass fibers produced by suspending the glass fibers of a first group having a first determined diameter and glass fibers of a second group having a different fiber diameter, in a gaseous medium, and collecting the glass fibers suspended on a foraminous material, with the conditions of: (a) that the separator has not been flooded or subjected to crystallization or hydroentanglement, and (b) that the fibers of the sheet have not been lacquered with a liquid.

21. In a storage battery as mentioned in claim 1, the improvement wherein the sheets of the separator consist essentially of interlaced glass fibers and organic fibers produced by suspending the glass fibers having a first determined diameter and organic fibers having a fiber diameter different, in a gaseous medium, and collecting the glass and organic fibers suspended on a foraminous material.

22. In a storage battery as recited in claim 1, the improvement wherein at least the thickness, the tensile strength or the stiffness of the separating sheets have been modified, after the sheet was collected, by spraying a liquid in it and then compressing the sheet.

23. In a storage battery as mentioned in claim 1, the improvement where the collected fibers were subjected to a cross-splicing process.

24. In a storage battery consisting of a plurality of lead plates in a closed box, a separator of sheets of fibrous sheets between adjacent plates, and a body of an electrolyte sulfuric acid absorbed by each of the separators and kept in contact with each one of the adjacent plates, the improvement where the separating sheets consist mainly of interwoven glass or organic fibers produced by suspending the fibers in a gaseous or liquid medium, and collecting the fibers suspended in a foraminous material in at least four discontinuous layers, with the condition that the mass of the fibers 2 has a BET surface area from 0.2 to 5 m per gram.

25. In a storage battery as mentioned in claim 24, the improvement wherein the collected fibers are mainly glass microfibers.

26. In a storage battery as mentioned in claim 24, the improvement wherein the collected fibers are mainly organic microfibers.

27. In a storage battery as recited in claim 24, the improvement wherein a particulate, inorganic material is suspended and harvested with the fibers, and the inorganic particulate material constitutes from 5 to 90% of the total weight of the fibers and the particulate material.

28. In a storage battery as mentioned in claim 24, the improvement wherein the fibers are suspended in a liquid medium.

29. In a storage battery as mentioned in claim 24, the improvement wherein the fibers are suspended in a gaseous medium.

30. In a storage battery consisting of a plurality of lead plates in a closed box, a separator of sheets of fibrous sheets between the adjacent plates, and a body of an electrolyte sulfuric acid absorbed by each of the separators and held in contact with each of the adjacent plates, the improvement wherein the sheets of the separator consist mainly of intertwined glass fibers, intertwined organic fibers or interwoven glass and organic fibers produced by carding fiber bundles, suspending the carded fibers in a gaseous medium and collecting the fibers suspended on a foraminous material, with the condition that the fiber mass has a BET surface area from 0.2 to 5 m per gram. In the storage battery as recited in claim 30, the improvement wherein at least two different kinds of organic fibers in bundles are carded, and fibers of one class having a melting temperature at least 20 ° C lower than the temperature of fusion of the fibers of the other kind, [sic]

31. In the storage battery as mentioned in claim 30, the improvement wherein the suspended fibers consist of organic fibers.

32. In the storage battery as recited in claim 31, the improvement wherein the organic fibers are polyolefins.

33. In the storage battery as mentioned in claim 32, the improvement where the polyolefin fibers are treated to make the hydrophilic.

34. In the storage battery as recited in claim 31, the improvement wherein the organic fibers are polyester.

35. In the storage battery as mentioned in claim 31, the improvement wherein the organic fibers are acrylic.

36. In the storage battery as mentioned in claim 30, the improvement where the suspended fibers are glass fibers, the particulate inorganic material is suspended in the gaseous medium with the glass fibers, and the glass fibers and the particulate inorganic material is collected on a foraminous material.

37. In the storage battery as mentioned in claim 24, the improvement wherein the suspended and collected fibers are mainly glass microfibers and chopped short glass fibers.

38. In the storage battery as recited in claim 24, the improvement wherein the suspended and collected fibers are glass microfibers, chopped short glass fibers or both and from 5 to 95 percent w / w of organic fibers.

39. In the storage battery as recited in claim 38, the improvement wherein the organic fibers are polyolefin fibers.

40. In the storage battery as recited in claim 38, the improvement wherein the organic fibers are Sulfar fibers.

41. In the storage battery as recited in claim 38, the improvement wherein the organic fibers are polyester fibers.

42. In the storage battery as recited in claim 38, the improvement wherein the organic fibers are acrylic fibers.

43. In the storage battery as recited in claim 38, the improvement wherein the organic fibers are cellulose fibers.

44. In the storage battery as recited in claim 38, the improvement wherein at least some of the organic fibers are fibers and components.

45. In the storage battery as recited in claim 44, the improvement wherein the fibers and components act as a binder for the separator in order to improve the stiffness of the separator, the cycling characteristics of the battery and the resistance from the battery to the vibration.

46. In the storage battery as recited in claim 30, the improvement wherein some of the interlaced fibers are glass microfibers having a BET surface area from 0.2 to 5 m2 per gram.

47. In the storage battery as recited in claim 36, the improvement wherein the suspended glass fibers are a mixture of microfibers and chopped short glass fibers.

48. In the storage battery as recited in claim 30, the improvement wherein the suspended fibers are organic fibers, a particulate inorganic material is suspended in the gaseous medium with the organic fibers, and the organic fibers and the particulate inorganic material they are collected on a foraminous material.

49. In the storage battery as recited in claim 48, the improvement wherein the particulate material constitutes from 5% w / w to 90% w / w of the total organic fibers and the particulate material.

50. In the storage battery as mentioned in claim 31, the improvement wherein at least some of the organic fibers are bicomponent fibers.

51. In the storage battery as recited in claim 50, the improvement wherein at least some of the fibers and components are thermally bonded to the adjacent fibers at contact points.

52. In the storage battery as mentioned in claim 30, the improvement wherein at least some of the fibers are bicomponent fibers.

53. In the storage battery as recited in claim 30, the improvement wherein at least two different kinds of organic fibers in bundles are carded, suspended and harvested, and fibers of a kind having a melting temperature of at least 20 ° C less than the melting temperature of the fibers of the other kind.

54. In the storage battery as recited in claim 31, the improvement wherein the suspended organic fibers are Sulfar.

55. In the storage battery as recited in claim 27, the improvement wherein the inorganic particulate material increases the BET surface area of the separator by at least 100 m / g and improves the stratification of the battery during flotation or cycling applications. .

56. In the storage battery as mentioned in claim 24, the improvement wherein the compositions of the layers are different from each other.

57. In the storage battery as claimed in claim 1, the improvement of a separator produced by suspending newly formed glass fibers in a gaseous medium, collecting the glass fibers suspended on a foraminous material, and separating the collected fibers from the material foraminous

58. In the storage battery as recited in claim 30, the improvement wherein at least two different kinds of organic fibers in bundles are carded, and fibers of one class having a melting temperature of at least 20 ° C less than melting temperature of the fibers of the other kind.

59. A fibrous sheet for use as a battery plate separator that is composed primarily of 'glass microfibers, having a BET surface area with nitrogen base, between 0.2 and 5 m per gram, with the conditions of: (a) ) that the sheet has not been subjected to crystallization or hydroentanglement, and (b) that the fibers of the sheet have not been lacquered with a liquid.

60. A fibrous sheet for use as a battery plate separator as recited in claim 59, wherein the glass microfibers suspended in a gaseous medium, collected on a foraminous surface and then separated from the foraminous surface constitute the fibrous sheet .

61. The fibrous sheet for use as a battery plate separator as recited in claim 59, wherein freshly formed glass microfibers, suspended in a gaseous medium, collected on a foraminous surface and then separated from the foraminous surface, constitute the fibrous leaf.