Thermal insulation material for battery

Abstract

Insulation materials for batteries are generally described. The insulation materials described herein have a number of advantages. For example, in some embodiments, the thermal insulation material has desirable thermal characteristics, such as low thermal conductivity and / or high thermal stability. As another example, in some embodiments, the thermal insulation materials described herein have desirable structural properties, such as having a relatively low thickness and / or beneficial mechanical properties. The insulation materials described herein may also have a desired combination of thermal and structural properties.

Description

Technical Field

[0001] Articles for thermally insulating batteries and related systems and methods are generally described. Background Art

[0002] Electrochemical cells (e.g., lithium-ion electrochemical cells or electrochemical cells with lithium metal anodes) may overheat or catch fire during use. If a battery including a plurality of electrochemical cells does not include proper thermal insulation, heat and / or fire generated in one electrochemical cell may undesirably spread to other electrochemical cells, which may pose a safety hazard and / or reduce overall battery performance. Therefore, improved thermal insulation materials are needed. Summary of the invention

[0003] Thermal insulation materials for batteries are generally described.In some cases, the subject matter of the present disclosure relates to interrelated products, alternative solutions to a particular problem, and / or a plurality of different uses of one or more systems and / or articles.

[0004] In one aspect, a battery is provided. In some embodiments, the battery includes: a plurality of electrochemical cells, the plurality of electrochemical cells including a first electrochemical cell and a second electrochemical cell; and a nonwoven fiber web positioned between the first electrochemical cell and the second electrochemical cell, wherein: the nonwoven fiber web comprises glass fibers; the glass fibers comprise high softening point fibers, the high softening point fibers comprising less than or equal to 0.8 wt % Na2O and / or less than or equal to 0.8 wt % K2O; the high softening point fibers account for greater than or equal to 30 wt % of the glass fibers; the glass fibers account for greater than 80 wt % of the nonwoven fiber web; and the average length of the glass fibers is greater than or equal to 0.5 mm and less than or equal to 7 mm.

[0005] In another aspect, a battery is provided. In some embodiments, the battery includes: a plurality of electrochemical cells, the plurality of electrochemical cells including a first electrochemical cell and a second electrochemical cell; and a wet-laid nonwoven web positioned between the first electrochemical cell and the second electrochemical cell, wherein: the nonwoven web comprises glass fibers; the glass fibers comprise high softening point fibers, the high softening point fibers comprising less than or equal to 0.8 wt % Na2O and / or less than or equal to 0.8 wt % K2O; and the high softening point fibers account for greater than or equal to 30 wt % of the glass fibers; and the glass fibers account for greater than 80 wt % of the nonwoven web.

[0006] In yet another aspect, a battery is provided. In some embodiments, the battery includes: a plurality of modules, the plurality of modules including a first module and a second module; and a nonwoven fiber web positioned between the first module and the second module, wherein: the nonwoven fiber web comprises glass fibers; the glass fibers comprise high softening point fibers, the high softening point fibers comprising less than or equal to 0.8 wt % Na2O and / or less than or equal to 0.8 wt % K2O; the high softening point fibers account for greater than or equal to 30 wt % of the glass fibers; the glass fibers account for greater than 80 wt % of the nonwoven fiber web; and the average length of the glass fibers is greater than or equal to 0.5 mm and less than or equal to 7 mm.

[0007] In yet another aspect, a battery is provided. In some embodiments, the battery comprises: a plurality of modules, the plurality of modules comprising a first module and a second module; and a wet-laid nonwoven web positioned between the first module and the second module, wherein: the nonwoven web comprises glass fibers; the glass fibers comprise high softening point fibers, the high softening point fibers comprising less than or equal to 0.8 wt % Na2O and / or less than or equal to 0.8 wt % K2O; and the high softening point fibers account for greater than or equal to 30 wt % of the glass fibers; and the glass fibers account for greater than 80 wt % of the nonwoven web.

[0008] Other advantages and novel features of the present disclosure will become apparent from the following detailed description of multiple non-limiting embodiments of the present disclosure when considered in conjunction with the accompanying drawings. In the event that the present specification and documents incorporated by reference include conflicting and / or inconsistent disclosures, the present specification shall prevail. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Non-limiting embodiments of the present disclosure will be described by way of example with reference to the accompanying drawings, which are schematic and are not intended to be drawn to scale unless otherwise indicated. In the drawings, each identical or nearly identical component shown is generally represented by a single reference numeral. For clarity, not every component is labeled in every figure, nor is every component of every embodiment of the disclosure shown, where an illustration is not necessary to enable one of ordinary skill in the art to understand the present disclosure. In the drawings:

[0010] Figure 1 shows a top view schematic diagram of a non-limiting nonwoven web according to some embodiments;

[0011] Figure 2A shows a schematic side view of a nonwoven web positioned between a first electrochemical cell and a second electrochemical cell according to some embodiments;

[0012] Figure 2Bshows a schematic cross-sectional view of a non-limiting battery including more than two electrochemical cells and more than one nonwoven fiber web according to some embodiments;

[0013] Figure 3 shows a schematic cross-sectional view of a nonwoven web positioned between a first module and a second module according to some embodiments;

[0014] Figure 4 shows a scanning electron micrograph of a nonwoven web according to some embodiments;

[0015] Figure 5 shows a scanning electron micrograph of a nonwoven web according to some embodiments;

[0016] Figure 6 shows a scanning electron micrograph of a nonwoven web according to some embodiments;

[0017] Figure 7 shows a scanning electron micrograph of a nonwoven web according to some embodiments;

[0018] Figure 8 shows a scanning electron micrograph of a nonwoven web according to some embodiments;

[0019] Fig. 9 shows a scanning electron micrograph of a nonwoven web according to some embodiments;

[0020] Fig.10 shows a scanning electron micrograph of a nonwoven web according to some embodiments; and

[0021] Fig.11 Shown are scanning electron micrographs of nonwoven webs according to some embodiments. DETAILED DESCRIPTION

[0022] Thermal insulation materials for batteries are generally described. The thermal insulation materials described herein have many advantages. For example, in some embodiments, the thermal insulation materials have desired thermal properties, such as low thermal conductivity and / or high thermal stability. As another example, in some embodiments, the thermal insulation materials described herein have desired structural properties, such as having relatively low thickness and / or beneficial mechanical properties. The thermal insulation materials described herein can also have a combination of desired thermal properties and structural properties.

[0023] In some embodiments, the thermal insulation material adopts the form of a nonwoven web. The nonwoven web may include one or more components that are beneficial for use in the thermal insulation material. In other words, the nonwoven web may include a combination of components that make the nonwoven web show one or more beneficial thermal properties described herein in an integral form. For example, the nonwoven web may include high softening point fibers, which may advantageously improve the thermal stability of the nonwoven web and / or reduce its shrinkage at high temperatures. As another example, the nonwoven web may include useful additives, such as flame retardants and / or aerogels.

[0024] In some embodiments, the nonwoven web used as a thermal insulation material comprises one or more additional components in addition to the component that improves thermal properties. For example, the thermal insulation material can include one or more components that enhance the structural properties and / or mechanical properties of the nonwoven web. Such components can include fibers, such as glass fibers and / or synthetic fibers in addition to high softening point fibers.

[0025] Some nonwoven webs described herein have low thickness. Without wishing to be bound by any particular theory, it is believed that such nonwoven webs may be desirable for maintaining the energy density of the battery in which they are positioned. Some such nonwoven webs may be wet-laid nonwoven webs and / or may comprise relatively short fibers. Without wishing to be bound by any particular theory, it is believed that wet-laid webs may be particularly suitable for forming particularly thin nonwoven webs, such as those thinner nonwoven webs than those formed using other techniques (such as air-laid webs). It is also believed that relatively short fibers may promote wet-laid webs.

[0026] Figure 1 A top view of a non-limiting nonwoven web 101 is shown. Some nonwoven webs can be configured to inhibit heat flow between electrochemical cells of a battery, thereby improving battery performance and / or safety. For example, as described in further detail elsewhere herein, the nonwoven web can have a particularly low thermal conductivity and / or contain one or more flame retardants.

[0027] In some embodiments, the nonwoven web is positioned in a battery. As an example, the nonwoven web can be positioned between two electrochemical cells present in a battery. Figure 2A A non-limiting schematic side view of a nonwoven web 201 positioned between a first electrochemical cell 203 and a second electrochemical cell 205 is shown. Figure 2AAs shown, the nonwoven web 201 can directly contact at least a portion of the first electrochemical cell 203 and / or the second electrochemical cell 205, or can be separated from one or both of the electrochemical cell 203 and the electrochemical cell 205 by one or more intermediate materials (not shown). For example, in some embodiments, the nonwoven web can be separated from the electrochemical cell by an intermediate material, and the intermediate material (e.g., compressible foam) can withstand a relatively high degree of compression and / or can accommodate dimensional changes (e.g., expansion, contraction) during charging and / or discharging of the electrochemical cell.

[0028] In some embodiments, the nonwoven web is positioned in a battery comprising more than two electrochemical cells. In some such embodiments, the battery may include a plurality of nonwoven webs positioned between pairs of electrochemical cells. Figure 2B A schematic cross-sectional view of a non-limiting battery 350 is shown, the non-limiting battery 350 comprising more than two electrochemical cells and more than one nonwoven fiber web. Figure 2B As shown, the battery 350 includes a first nonwoven fiber web 301 (separating the first electrochemical cell 303 from the second electrochemical cell 305) and a second nonwoven fiber web 311 (separating the second electrochemical cell 305 from the third electrochemical cell 313). Figure 2B As shown, in some embodiments, some nearest neighbor electrochemical cell pairs may have a nonwoven fiber web positioned between them, while some nearest neighbor electrochemical cell pairs may not have a nonwoven fiber web positioned between them. All nearest neighbor electrochemical cells in the battery may also have a nonwoven fiber web positioned between them.

[0029] As used herein, a nearest neighbor electrochemical cell is an electrochemical cell that is located in a common stack and is not separated by other electrochemical cells. An electrochemical cell at the end of the stack has one nearest neighbor electrochemical cell, and an electrochemical cell in the middle of the stack has two nearest neighbor electrochemical cells. For example, referring to Figure 2B , the electrochemical cell 313 has two nearest neighbor electrochemical cells: the electrochemical cell 305 (the electrochemical cell 313 is separated from it by the nonwoven fiber web 311) and the electrochemical cell 315 (the electrochemical cell 313 is not separated from it by the nonwoven fiber web). As another example, and also referring to Figure 2B , electrochemical cell 315 has one nearest neighbor electrochemical cell: electrochemical cell 313 .

[0030] In some embodiments, the battery includes a plurality of modules. Typically, each module includes a plurality of electrochemical cells, such as those described elsewhere herein. In some embodiments, all or most of the electrochemical cells of the battery are positioned in the modules present in the battery. The plurality of electrochemical cells present in the module can be mechanically coupled to each other via the module. The module may include one or more nonwoven webs. Such a nonwoven web may be positioned between the electrochemical cells present in the module. In some embodiments, the battery includes: a module that does not include a nonwoven web. For example, in some embodiments, the battery does not include: a module that includes a nonwoven web. The battery may also include: some modules that include a nonwoven web and other modules that do not include a nonwoven web.

[0031] In some embodiments, a battery includes a nonwoven fiber web positioned between two modules present therein. Figure 3 Such a battery (battery 450) is schematically shown. Figure 3 In the embodiment, the nonwoven web 401 is positioned between the module 461 and the module 463. Figure 3 As shown, the nonwoven web 401 may directly contact at least a portion of the first module 461 and / or the second module 463, or may be separated from one or both of the modules 461 and 463 by one or more intermediate materials (not shown).

[0032] The nonwoven web positioned between two modules present in the battery can separate the modules and separate the electrochemical cells present in different modules. As an example, the nonwoven web positioned between two modules can also separate the electrochemical cells present in the modules from each other by separating the modules from each other. Thus, such a nonwoven web can separate a first electrochemical cell belonging to a first module from a second electrochemical cell belonging to a second module.

[0033] In some embodiments, the nonwoven web is positioned in a battery comprising more than two modules. In some such embodiments, the battery may include a plurality of nonwoven webs positioned between multiple pairs of modules. In some embodiments, some nearest neighbor module pairs may have a nonwoven web positioned therebetween, and some nearest neighbor module pairs may not have a nonwoven web positioned therebetween. All nearest neighbor modules in the battery may also have a nonwoven web positioned therebetween.

[0034] As used herein, the nearest neighbor module is a module that is positioned in a common cell and is not separated by other modules. In some embodiments, the modules can be stacked to form one or more stacks. The module at the end of the stack has one nearest neighbor module in its stack and one nearest neighbor module in each stack adjacent to it. The module in the middle of the stack has two nearest neighbor modules in its stack and one nearest neighbor module in each stack adjacent to it.

[0035] In some embodiments, the nonwoven web may be formed in a manner different from Figure 2A , Figure 2B and Figure 3 The nonwoven webs are arranged in a battery in the manner shown. For example, the nonwoven web can be folded so that the first portion of the nonwoven web separates the first pair of nearest neighbor electrochemical cells, and the second portion of the nonwoven web separates the second pair of nearest neighbor electrochemical cells. As another example, the battery can include a nonwoven web that is folded so that it is wound between the electrochemical cells of the battery in a serpentine configuration. Similarly, the nonwoven webs can be folded so that they include a first portion separating a first pair of nearest neighbor modules and a second portion separating a second pair of nearest neighbor modules, and / or can be folded so that they are wound between the modules in the battery in a serpentine configuration.

[0036] Of course, it should be understood that although Figure 2B The battery 350 and Figure 3 The battery 450 has a stacked configuration, but generally, the battery in which the nonwoven fiber web described herein is positioned can include electrochemical cells and modules in any of a variety of spatial configurations (e.g., laterally offset or wrapped electrochemical cell configurations), and the present disclosure is not limited thereto.

[0037] The nonwoven web described herein may include glass fibers. Glass fibers may be included in any of various suitable amounts. In some embodiments, relative to the gross weight of the nonwoven web, the web includes glass fibers in an amount of greater than or equal to 50 wt %, greater than or equal to 55 wt %, greater than or equal to 60 wt %, greater than or equal to 65 wt %, greater than or equal to 70 wt %, greater than or equal to 75 wt %, greater than or equal to 80 wt %, greater than 80 wt %, or greater than or equal to 85 wt %. In some embodiments, relative to the gross weight of the nonwoven web, the web includes glass fibers in an amount of less than or equal to 100 wt %, less than or equal to 95 wt %, less than or equal to 90 wt %, less than or equal to 85 wt %, less than or equal to 80 wt %, less than or equal to 75 wt %, or less than or equal to 70 wt %. Combinations of these ranges are also possible (e.g., greater than or equal to 50 wt % and less than or equal to 100 wt %, greater than or equal to 65 wt % and less than or equal to 100 wt %, or greater than or equal to 80 wt % and less than or equal to 100 wt %, relative to the total weight of the nonwoven web). In some embodiments, the glass fibers comprise 100 wt % of the nonwoven web.

[0038] Glass fiber can have any one of various suitable average fiber diameters. In some embodiments, nonwoven webs include glass fibers having an average diameter greater than or equal to 1 micron, greater than or equal to 2 microns, greater than or equal to 3 microns, greater than or equal to 4 microns, greater than or equal to 5 microns, greater than or equal to 6 microns, greater than or equal to 7 microns, or greater than or equal to 8 microns. In some embodiments, nonwoven webs include glass fibers having an average diameter less than or equal to 20 microns, less than or equal to 19 microns, less than or equal to 18 microns, less than or equal to 17 microns, less than or equal to 16 microns, less than or equal to 15 microns, less than or equal to 14 microns, less than or equal to 13 microns, less than or equal to 12 microns, less than or equal to 11 microns, less than or equal to 10 microns, less than or equal to 9 microns, less than or equal to 8 microns, less than or equal to 7 microns, less than or equal to 6 microns, or less than or equal to 5 microns. Combinations of these ranges are also possible (e.g., greater than or equal to 1 micron and less than or equal to 20 microns, greater than or equal to 1 micron and less than or equal to 13 microns, greater than or equal to 3 microns and less than or equal to 10 microns, or greater than or equal to 4 microns and less than or equal to 8 microns). Other ranges are also possible.

[0039] The nonwoven webs described herein may include glass fibers having any of a variety of suitable average lengths. In some embodiments, the nonwoven webs include glass fibers having an average length greater than or equal to 0.5 mm, greater than or equal to 0.6 mm, greater than or equal to 0.7 mm, greater than or equal to 0.8 mm, greater than or equal to 0.9 mm, greater than or equal to 1 mm, greater than or equal to 2 mm, greater than or equal to 3 mm, greater than or equal to 4 mm, greater than or equal to 5 mm, greater than or equal to 6 mm, greater than or equal to 7 mm, or greater than or equal to 8 mm. In some embodiments, the nonwoven webs include glass fibers having an average length less than or equal to 15 mm, less than or equal to 14 mm, less than or equal to 13 mm, less than or equal to 12 mm, less than or equal to 11 mm, less than or equal to 10 mm, less than or equal to 9 mm, less than or equal to 8 mm, less than or equal to 7 mm, less than or equal to 6 mm, or less than or equal to 5 mm. Combinations of these ranges are also possible (e.g., greater than or equal to 0.5 mm and less than or equal to 15 mm, greater than or equal to 1 mm and less than or equal to 11 mm, greater than or equal to 2 mm and less than or equal to 9 mm, or greater than or equal to 3 mm and less than or equal to 7 mm). Other ranges are also possible.

[0040] The present disclosure recognizes that some glass fibers, such as those having high thermal stability (referred to herein as high softening point fibers), can provide a number of advantages when incorporated into nonwoven webs for use in thermal insulation materials. For example, as described in more detail below, high softening point fibers may be less susceptible to softening and / or shrinking when heated. The high softening point fibers may comprise silicate glass, alumina glass, or aluminosilicate glass in any of a variety of suitable chemical compositions.

[0041] The present disclosure recognizes that, according to some embodiments, it can be advantageous for the high softening point fibers to include relatively small amounts of alkali metal oxides, such as sodium oxides and / or potassium oxides. Without wishing to be bound by any particular theory, sodium and potassium may disrupt the covalent bond network within the aluminosilicate glass, thereby reducing its thermal stability and its softening point. In some embodiments, Na2O is present in the high softening point fibers in an amount of less than or equal to 0.8 wt%, less than or equal to 0.7 wt%, less than or equal to 0.6 wt%, less than or equal to 0.5 wt%, less than or equal to 0.4 wt%, or less than or equal to 0.3 wt%, relative to the total weight of the high softening point fibers. In some embodiments, Na2O is present in the high softening point fibers in an amount of greater than or equal to 0.1 wt%, greater than or equal to 0.2 wt%, greater than or equal to 0.3 wt%, greater than or equal to 0.4 wt%, greater than or equal to 0.5 wt%, or greater than or equal to 0.6 wt%, relative to the total weight of the high softening point fibers. Combinations of these ranges are also possible (e.g., greater than or equal to 0.1 wt % and less than or equal to 0.8 wt %, greater than or equal to 0.1 wt % and less than or equal to 0.6 wt %, or greater than or equal to 0.1 wt % and less than or equal to 0.5 wt %, relative to the total weight of the high softening point fiber). Other ranges are also possible.

[0042] In some embodiments, K2O is present in the high softening point fiber in an amount of less than or equal to 0.8 wt%, less than or equal to 0.75 wt%, less than or equal to 0.7 wt%, less than or equal to 0.65 wt%, less than or equal to 0.6 wt%, less than or equal to 0.55 wt%, less than or equal to 0.5 wt%, less than or equal to 0.45 wt%, or less than or equal to 0.4 wt%, relative to the total weight of the high softening point fiber. In some embodiments, K2O is present in the high softening point fiber in an amount greater than or equal to 0 wt%, greater than or equal to 0.05 wt%, greater than or equal to 0.1 wt%, greater than or equal to 0.15 wt%, greater than or equal to 0.2 wt%, greater than or equal to 0.25 wt%, or greater than or equal to 0.3 wt%, relative to the total weight of the high softening point fiber. Combinations of these ranges are also possible (e.g., greater than or equal to 0 wt % and less than or equal to 0.8 wt %, greater than or equal to 0.05 wt % and less than or equal to 0.6 wt %, or greater than or equal to 0.05 wt % and less than or equal to 0.5 wt %, relative to the total weight of the high softening point fiber). Other ranges are also possible. In some embodiments, K2O is present in the high softening point fiber in an amount of 0 wt %.

[0043] A relatively small amount of boron can be associated with a favorable high softening point. The nonwoven web can include high softening point fibers with B2O3 of any one of various suitable amounts. In some embodiments, B2O3 is present in the high softening point fibers in an amount of less than or equal to 10 wt%, less than or equal to 9 wt%, less than or equal to 8 wt%, less than or equal to 7 wt%, less than or equal to 6 wt%, less than or equal to 5 wt%, less than or equal to 4 wt%, less than or equal to 3 wt%, or less than or equal to 2 wt%, relative to the gross weight of the high softening point fibers. In some embodiments, B2O3 is present in the high softening point fibers in an amount of greater than or equal to 0 wt%, greater than or equal to 1 wt%, greater than or equal to 2 wt%, greater than or equal to 3 wt%, or greater than or equal to 4 wt%, relative to the gross weight of the high softening point fibers. Combinations of these ranges are also possible (e.g., greater than or equal to 0 wt % and less than or equal to 10 wt %, greater than or equal to 0 wt % and less than or equal to 7 wt %, or greater than or equal to 0 wt % and less than or equal to 2 wt %, relative to the total weight of the high softening point fiber). Other ranges are also possible. In some embodiments, B2O3 is present in the high softening point fiber in an amount of 0 wt %.

[0044] In some embodiments, the high softening point fibers may comprise a type of glass known commercially as E-glass or ECR-glass. Further details regarding possible compositions of the high softening point fibers are provided below.

[0045] High softening point fiber (such as E-glass fiber or ECR-glass fiber) can comprise any one of various compounds.For example, nonwoven fiber web can comprise high softening point fiber with SiO2 of any one of various suitable amounts.In some embodiments, relative to the gross weight of high softening point fiber, SiO2 is present in the high softening point fiber in an amount of greater than or equal to 50 wt %, greater than or equal to 51 wt %, greater than or equal to 52 wt %, greater than or equal to 53 wt %, greater than or equal to 54 wt %, greater than or equal to 55 wt %, greater than or equal to 56 wt %, greater than or equal to 57 wt %, greater than or equal to 58 wt %, greater than or equal to 59 wt %, greater than or equal to 60 wt %, greater than or equal to 61 wt %, greater than or equal to 62 wt %, greater than or equal to 63 wt %, greater than or equal to 64 wt %, greater than or equal to 65 wt %, greater than or equal to 66 wt %, greater than or equal to 67 wt %, greater than or equal to 68 wt %, or greater than or equal to 69 wt %. In some embodiments, SiO2 is present in the high softening point fiber in an amount of less than or equal to 70 wt%, less than or equal to 69 wt%, less than or equal to 68 wt%, less than or equal to 67 wt%, less than or equal to 66 wt%, less than or equal to 65 wt%, less than or equal to 64 wt%, less than or equal to 63 wt%, less than or equal to 62 wt%, less than or equal to 61 wt%, or less than or equal to 60 wt%, relative to the total weight of the high softening point fiber. Combinations of these ranges are also possible (e.g., greater than or equal to 50 wt% and less than or equal to 70 wt%, greater than or equal to 50 wt% and less than or equal to 65 wt%, greater than or equal to 55 wt% and less than or equal to 64 wt%, or greater than or equal to 60 wt% and less than or equal to 64 wt%, relative to the total weight of the high softening point fiber). Other ranges are also possible.

[0046] The nonwoven web may include a high softening point fiber having any of various suitable amounts of Al2O3. In some embodiments, Al2O3 is present in the high softening point fiber in an amount of greater than or equal to 6 wt%, greater than or equal to 7 wt%, greater than or equal to 8 wt%, greater than or equal to 9 wt%, greater than or equal to 10 wt%, or greater than or equal to 11 wt%, relative to the gross weight of the high softening point fiber. In some embodiments, Al2O3 is present in the high softening point fiber in an amount of less than or equal to 16 wt%, less than or equal to 15 wt%, less than or equal to 14 wt%, less than or equal to 13 wt%, less than or equal to 12 wt%, or less than or equal to 11 wt%, relative to the gross weight of the high softening point fiber. Combinations of these ranges are also possible (e.g., greater than or equal to 6 wt% and less than or equal to 16 wt%, greater than or equal to 8 wt% and less than or equal to 15 wt%, or greater than or equal to 10 wt% and less than or equal to 14 wt%). Other ranges are also possible.

[0047] The nonwoven web may include a high softening point fiber having any one of various suitable amounts of CaO. In some embodiments, relative to the gross weight of the high softening point fiber, CaO is present in the high softening point fiber in an amount of greater than or equal to 15 wt%, greater than or equal to 16 wt%, greater than or equal to 17 wt%, greater than or equal to 18 wt%, greater than or equal to 19 wt%, or greater than or equal to 20 wt%. In some embodiments, relative to the gross weight of the high softening point fiber, CaO is present in the high softening point fiber in an amount of less than or equal to 25 wt%, less than or equal to 24 wt%, less than or equal to 23 wt%, less than or equal to 22 wt%, less than or equal to 21 wt%, or less than or equal to 20 wt%. Combinations of these ranges are also possible (e.g., relative to the gross weight of the high softening point fiber, greater than or equal to 15 wt% and less than or equal to 25 wt%, greater than or equal to 17 wt% and less than or equal to 23 wt%, or greater than or equal to 19 wt% and less than or equal to 21 wt%). Other ranges are also possible.

[0048] The nonwoven web may include high softening point fibers of MgO having any one of various suitable amounts. In some embodiments, MgO is present in the high softening point fibers in an amount greater than or equal to 0 wt%, greater than or equal to 0.1 wt%, greater than or equal to 0.2 wt%, greater than or equal to 0.5 wt%, greater than or equal to 1 wt%, or greater than or equal to 2 wt%, relative to the gross weight of the high softening point fibers. In some embodiments, MgO is present in the high softening point fibers in an amount less than or equal to 5 wt%, less than or equal to 4.5 wt%, less than or equal to 4 wt%, less than or equal to 3.5 wt%, less than or equal to 3 wt%, less than or equal to 2.5 wt%, or less than or equal to 2 wt%, relative to the gross weight of the high softening point fibers. Combinations of these ranges are also possible (e.g., greater than or equal to 0 wt% and less than or equal to 5 wt%, greater than or equal to 0.1 wt% and less than or equal to 4 wt%, or greater than or equal to 0.2 wt% and less than or equal to 2.5 wt%). Other ranges are possible.In some embodiments, MgO is present in the high softening point fibers in an amount of 0 wt%.

[0049] The nonwoven web may include high softening point fibers having any of various suitable amounts of ZnO. In some embodiments, ZnO is present in the high softening point fibers in an amount greater than or equal to 0 wt%, greater than or equal to 0.1 wt%, greater than or equal to 0.2 wt%, greater than or equal to 0.3 wt%, greater than or equal to 0.4 wt%, or greater than or equal to 0.5 wt%, relative to the total weight of the high softening point fibers. In some embodiments, ZnO is present in the high softening point fibers in an amount less than or equal to 1 wt%, less than or equal to 0.9 wt%, less than or equal to 0.8 wt%, less than or equal to 0.7 wt%, less than or equal to 0.6 wt%, less than or equal to 0.5 wt%, less than or equal to 0.4 wt%, less than or equal to 0.3 wt%, or less than or equal to 0.2 wt%, relative to the total weight of the high softening point fibers. Combinations of these ranges are also possible (e.g., greater than or equal to 0 wt % and less than or equal to 1 wt %, greater than or equal to 0 wt % and less than or equal to 0.5 wt %, or greater than or equal to 0 wt % and less than or equal to 0.2 wt %, relative to the total weight of the high softening point fiber). Other ranges are also possible. In some embodiments, ZnO is present in the high softening point fiber in an amount of 0 wt %.

[0050] The nonwoven web may include high softening point fibers having any of various suitable amounts of TiO2. In some embodiments, TiO2 is present in the high softening point fibers in an amount of greater than or equal to 0.2 wt%, greater than or equal to 0.3 wt%, greater than or equal to 0.4 wt%, greater than or equal to 0.5 wt%, greater than or equal to 0.8 wt%, or greater than or equal to 1 wt%, relative to the total weight of the high softening point fibers. In some embodiments, TiO2 is present in the high softening point fibers in an amount of less than or equal to 2.5 wt%, less than or equal to 2.2 wt%, less than or equal to 2 wt%, less than or equal to 1.8 wt%, less than or equal to 1.5 wt%, less than or equal to 1.2 wt%, less than or equal to 1 wt%, less than or equal to 0.8 wt%, or less than or equal to 0.5 wt%, relative to the total weight of the high softening point fibers. Combinations of these ranges are also possible (e.g., greater than or equal to 0.2 wt % and less than or equal to 2.5 wt %, greater than or equal to 0.2 wt % and less than or equal to 1 wt %, or greater than or equal to 0.2 wt % and less than or equal to 0.5 wt %, relative to the total weight of the high softening point fiber). Other ranges are also possible.

[0051] The nonwoven web may include high softening point fibers having any of various suitable amounts of Fe2O3. In some embodiments, Fe2O3 is present in the high softening point fibers in an amount greater than or equal to 0 wt%, greater than or equal to 0.1 wt%, greater than or equal to 0.2 wt%, greater than or equal to 0.3 wt%, or greater than or equal to 0.4 wt%, relative to the gross weight of the high softening point fibers. In some embodiments, Fe2O3 is present in the high softening point fibers in an amount less than or equal to 0.5 wt%, less than or equal to 0.4 wt%, less than or equal to 0.3 wt%, or less than or equal to 0.2 wt%, relative to the gross weight of the high softening point fibers. Combinations of these ranges are also possible (e.g., greater than or equal to 0 wt% and less than or equal to 0.5 wt%, greater than or equal to 0 wt% and less than or equal to 0.4 wt%, or greater than or equal to 0 wt% and less than or equal to 0.3 wt%). Other ranges are also possible. In some embodiments, Fe2O3 is present in the high softening point fiber in an amount of 0 weight percent.

[0052] The nonwoven web may include a high softening point fiber having any of various suitable amounts of F. In some embodiments, F is present in the high softening point fiber in an amount of greater than or equal to 0 wt%, greater than or equal to 0.01 wt%, greater than or equal to 0.02 wt%, greater than or equal to 0.05 wt%, greater than or equal to 0.075 wt%, greater than or equal to 0.1 wt%, greater than or equal to 0.15 wt%, greater than or equal to 0.2 wt%, or greater than or equal to 0.25 wt%, relative to the total weight of the high softening point fiber. In some embodiments, F is present in the high softening point fiber in an amount of less than or equal to 0.3 wt%, less than or equal to less than or equal to 0.25 wt%, less than or equal to 0.2 wt%, less than or equal to 0.15 wt%, less than or equal to 0.075 wt%, less than or equal to 0.05 wt%, less than or equal to 0.02 wt%, or less than or equal to 0.01 wt%. Combinations of these ranges are also possible (eg, greater than or equal to 0 wt % and less than or equal to 0.3 wt %). Other ranges are also possible. In some embodiments, F is present in the high softening point fiber in an amount of 0 wt %.

[0053] The nonwoven webs described herein may include high softening point fibers having any of a variety of suitable softening points. In some embodiments, the nonwoven webs include high softening point fibers having a softening point greater than or equal to 800°C, greater than or equal to 825°C, greater than or equal to 850°C, greater than or equal to 875°C, greater than or equal to 900°C, greater than or equal to 925°C, or greater than or equal to 950°C. In some embodiments, the nonwoven webs include high softening point fibers having a softening point less than or equal to 1,000°C, less than or equal to 975°C, less than or equal to 950°C, less than or equal to 925°C, or less than or equal to 900°C. Combinations of these ranges are also possible (e.g., greater than or equal to 800°C and less than or equal to 1,000°C, greater than or equal to 850°C and less than or equal to 1,000°C, or greater than or equal to 900°C and less than or equal to 1,000°C). Other ranges are also possible. The softening point of the high softening point fiber can be determined according to ASTM C338-1993.

[0054] The nonwoven webs described herein may contain high softening point fibers in any of various suitable amounts. In some embodiments, the nonwoven web contains high softening point fibers in an amount greater than or equal to 30 wt%, greater than or equal to 35 wt%, greater than or equal to 35 wt%, greater than or equal to 40 wt%, greater than or equal to 45 wt%, greater than or equal to 50 wt%, greater than or equal to 55 wt%, greater than or equal to 60 wt%, greater than or equal to 65 wt%, or greater than or equal to 70 wt%, relative to the gross weight of the nonwoven web. In some embodiments, the nonwoven web contains high softening point fibers in an amount less than or equal to 75 wt%, less than or equal to 70 wt%, less than or equal to 65 wt%, less than or equal to 60 wt%, less than or equal to 55 wt%, less than or equal to 50 wt%, less than or equal to 45 wt%, or less than or equal to 40 wt%, relative to the gross weight of the nonwoven web. Combinations of these ranges are also possible (e.g., greater than or equal to 30 wt % and less than or equal to 75 wt %, greater than or equal to 35 wt % and less than or equal to 65 wt %, or greater than or equal to 40 wt % and less than or equal to 60 wt %, relative to the total weight of the nonwoven web). Other ranges are also possible.

[0055] In some embodiments, the nonwoven web comprises high softening point fibers in an amount greater than or equal to 35 wt%, greater than 35 wt%, greater than or equal to 40 wt%, greater than or equal to 45 wt%, greater than or equal to 50 wt%, greater than or equal to 55 wt%, greater than or equal to 60 wt%, greater than or equal to 65 wt%, greater than or equal to 70 wt%, greater than or equal to 75 wt%, or greater than or equal to 80 wt%, relative to the total weight of the glass fibers in the nonwoven web. In some embodiments, the nonwoven web comprises high softening point fibers in an amount less than or equal to 85 wt%, less than or equal to 80 wt%, less than or equal to 75 wt%, less than or equal to 70 wt%, less than or equal to 65 wt%, less than or equal to 60 wt%, less than or equal to 55 wt%, or less than or equal to 50 wt%, relative to the total weight of the glass fibers in the nonwoven web. Combinations of these ranges are also possible (e.g., greater than or equal to 35 wt % and less than or equal to 85 wt %, greater than or equal to 40 wt % and less than or equal to 70 wt %, or greater than or equal to 45 wt % and less than or equal to 65 wt %, relative to the total weight of the glass fibers in the nonwoven web). Other ranges are also possible.

[0056] The nonwoven web described herein can include high softening point fibers with any one of various suitable diameters. In some embodiments, the nonwoven web includes a mean diameter greater than or equal to 2 microns, greater than or equal to 3 microns, greater than or equal to 4 microns, greater than or equal to 5 microns, greater than or equal to 6 microns, greater than or equal to 7 microns, or greater than or equal to 8 microns of high softening point fibers. In some embodiments, the nonwoven web includes a mean diameter less than or equal to 13 microns, less than or equal to 12 microns, less than or equal to 11 microns, less than or equal to 10 microns, less than or equal to 9 microns, less than or equal to 8 microns, less than or equal to 7 microns, less than or equal to 6 microns, or less than or equal to 5 microns of high softening point fibers. The combination of these scopes is also possible (for example, greater than or equal to 3 microns and less than or equal to 13 microns, greater than or equal to 4 microns and less than or equal to 10 microns, or greater than or equal to 5 microns and less than or equal to 8 microns). Other scopes are also possible.

[0057] The nonwoven web described herein can include high softening point fibers with any one of various suitable lengths. In some embodiments, the nonwoven web includes high softening point fibers with an average length greater than or equal to 3mm, greater than or equal to 4mm, greater than or equal to 5mm, greater than or equal to 6mm, greater than or equal to 7mm, or greater than or equal to 8mm. In some embodiments, the nonwoven web includes high softening point fibers with an average length less than or equal to 13mm, less than or equal to 12mm, less than or equal to 11mm, less than or equal to 10mm, less than or equal to 9mm, less than or equal to 8mm, less than or equal to 7mm, less than or equal to 6mm, or less than or equal to 5mm. The combination of these ranges is also possible (e.g., greater than or equal to 3mm and less than or equal to 13mm, greater than or equal to 4mm and less than or equal to 10mm, or greater than or equal to 5mm and less than or equal to 8mm). Other ranges are also possible.

[0058] In some embodiments, the nonwoven web comprises chopped strand glass fibers. Chopped strand glass fibers may include chopped strand glass fibers produced by drawing the melt of glass into continuous fibers from the sleeve tip and then cutting the continuous fibers into short fibers. Some chopped strand glass fibers may include fibers with relatively monodisperse fiber diameters and / or may include two or more fiber groups each with relatively monodisperse fiber diameters. Some chopped strand glass fibers may be relatively straight. In some embodiments, chopped strand glass fibers are provided (e.g., provided to a batch) in a relatively tangle-free form.

[0059] In some embodiments, the nonwoven web comprises chopped strand glass fibers that are high softening point fibers. The nonwoven web may also comprise chopped strand glass fibers that are not high softening point fibers. It should be understood that the chopped strand glass fibers present in the nonwoven web may comprise one or more types of chopped strand glass fibers described herein.

[0060] In some embodiments, the nonwoven web comprises chopped strand glass fibers in an amount greater than or equal to 30 wt%, greater than or equal to 35 wt%, greater than or equal to 40 wt%, greater than or equal to 45 wt%, greater than or equal to 50 wt%, greater than or equal to 55 wt%, greater than or equal to 60 wt%, greater than or equal to 65 wt%, or greater than or equal to 70 wt%, relative to the total weight of the nonwoven web. In some embodiments, the nonwoven web comprises chopped strand glass fibers in an amount less than or equal to 75 wt%, less than or equal to 70 wt%, less than or equal to 65 wt%, less than or equal to 60 wt%, less than or equal to 55 wt%, less than or equal to 50 wt%, or less than or equal to 45 wt%, relative to the total weight of the nonwoven web. Combinations of these ranges are also possible (e.g., greater than or equal to 30 wt % and less than or equal to 75 wt %, greater than or equal to 35 wt % and less than or equal to 65 wt %, or greater than or equal to 45 wt % and less than or equal to 60 wt %, relative to the total weight of the nonwoven web). Other ranges are also possible.

[0061] The nonwoven web described herein can include chopped strand glass fibers with any one of various suitable diameters. In some embodiments, the nonwoven web includes an average diameter greater than or equal to 2 microns, greater than or equal to 3 microns, greater than or equal to 4 microns, greater than or equal to 5 microns, greater than or equal to 6 microns, greater than or equal to 7 microns, or greater than or equal to 8 microns of chopped strand glass fibers. In some embodiments, the nonwoven web includes an average diameter less than or equal to 13 microns, less than or equal to 12 microns, less than or equal to 11 microns, less than or equal to 10 microns, less than or equal to 9 microns, less than or equal to 8 microns, less than or equal to 7 microns, less than or equal to 6 microns, or less than or equal to 5 microns of chopped strand glass fibers. The combination of these ranges is also possible (for example, greater than or equal to 3 microns and less than or equal to 13 microns, greater than or equal to 4 microns and less than or equal to 10 microns, or greater than or equal to 5 microns and less than or equal to 8 microns). Other ranges are also possible.

[0062] The nonwoven web described herein may include chopped strand glass fibers with any one of various suitable lengths. In some embodiments, the nonwoven web includes an average length greater than or equal to 3mm, greater than or equal to 4mm, greater than or equal to 5mm, greater than or equal to 6mm, greater than or equal to 7mm, or greater than or equal to 8mm of chopped strand glass fibers. In some embodiments, the nonwoven web includes an average length less than or equal to 13mm, less than or equal to 12mm, less than or equal to 11mm, less than or equal to 10mm, less than or equal to 9mm, less than or equal to 8mm, less than or equal to 7mm, less than or equal to 6mm, or less than or equal to 5mm of chopped strand glass fibers. The combination of these ranges is also possible (for example, greater than or equal to 3mm and less than or equal to 13mm, greater than or equal to 4mm and less than or equal to 10mm, or greater than or equal to 5mm and less than or equal to 8mm). Other ranges are also possible.

[0063] The nonwoven web can include short glass fibers. The short glass fibers can be formed by drawing a glass melt from a sleeve tip and then subjecting the drawn glass melt to a flame blowing or a rotary spinning (e.g., centrifugal spinning) process. Some short glass fibers can have a relatively wide fiber diameter distribution. Some short fibers can be relatively curled. In some embodiments, chopped strand glass fibers are provided in a relatively tangled form (e.g., provided to a batch). Without wishing to be bound by theory, in some embodiments, the curled short glass fibers can contribute to entanglement of the fibers in a web (e.g., other short glass fibers, chopped strand glass fibers, multi-component fibers). This entanglement can improve the mechanical properties of the nonwoven web by mechanically supporting the fibers in the nonwoven web.

[0064] In addition, in some embodiments, the nonwoven web comprises short glass fibers that are high softening point fibers. Thus, the short glass fibers (when present) may have some or all of the properties described above for high softening point fibers (e.g., composition, softening point, weight % relative to the total weight of glass fibers in the nonwoven web, average diameter, diameter, average length). The nonwoven web may also comprise short glass fibers that are not high softening point fibers.

[0065] In some embodiments, the nonwoven web comprises short glass fibers in an amount greater than or equal to 15 wt %, greater than or equal to 20 wt %, greater than or equal to 25 wt %, greater than or equal to 30 wt %, greater than or equal to 35 wt %, greater than or equal to 40 wt %, or greater than or equal to 45 wt %, relative to the total weight of the nonwoven web. In some embodiments, the nonwoven web comprises short glass fibers in an amount less than or equal to 55 wt %, less than or equal to 50 wt %, less than or equal to 45 wt %, less than or equal to 40 wt %, less than or equal to 35 wt %, less than or equal to 30 wt %, less than or equal to 25 wt %, or less than or equal to 20 wt %, relative to the total weight of the nonwoven web. Combinations of these ranges are also possible (e.g., greater than or equal to 15 wt % and less than or equal to 55 wt %, greater than or equal to 25 wt % and less than or equal to 50 wt %, or greater than or equal to 30 wt % and less than or equal to 45 wt %). Other ranges are also possible.

[0066] The nonwoven webs described herein may include short glass fibers having any of a variety of suitable diameters. In some embodiments, the nonwoven webs include short glass fibers having an average diameter greater than or equal to 0.4 microns, greater than or equal to 0.5 microns, greater than or equal to 0.6 microns, greater than or equal to 0.7 microns, greater than or equal to 0.8 microns, greater than or equal to 0.9 microns, greater than or equal to 1 micron, greater than or equal to 2 microns, greater than or equal to 3 microns, greater than or equal to 4 microns, greater than or equal to 5 microns, or greater than or equal to 6 microns. In some embodiments, the nonwoven webs include short glass fibers having an average diameter less than or equal to 10 microns, less than or equal to 9 microns, less than or equal to 8 microns, less than or equal to 7 microns, less than or equal to 6 microns, less than or equal to 5 microns, less than or equal to 4 microns, less than or equal to 3 microns, less than or equal to 2 microns, less than or equal to 1 micron, less than or equal to 0.9 microns, less than or equal to 0.8 microns, less than or equal to 0.7 microns, less than or equal to 0.6 microns, or less than or equal to 0.5 microns. Combinations of these ranges are also possible (e.g., greater than or equal to 0.4 microns and less than or equal to 10 microns, greater than or equal to 1 micron and less than or equal to 9 microns, greater than or equal to 2 microns and less than or equal to 7 microns, or greater than or equal to 3 microns and less than or equal to 5 microns). Other ranges are also possible.

[0067] The nonwoven web may include relatively polydisperse short glass fibers. In some embodiments, the nonwoven web includes short glass fibers (which may have an average fiber diameter within one or more of the above ranges) and includes at least some short glass fibers having a diameter greater than or equal to 0.3 microns, greater than or equal to 0.4 microns, greater than or equal to 0.5 microns, greater than or equal to 0.6 microns, greater than or equal to 0.7 microns, greater than or equal to 0.8 microns, greater than or equal to 0.9 microns, greater than or equal to 1 micron, greater than or equal to 1.5 microns, greater than or equal to 2 microns, greater than or equal to 3 microns, greater than or equal to 4 microns, greater than or equal to 5 microns, greater than or equal to 6 microns, greater than or equal to 7 microns, greater than or equal to 8 microns, greater than or equal to 9 microns, greater than or equal to 10 microns, greater than or equal to 11 microns, greater than or equal to 12 microns, or greater than or equal to 13 microns. In some embodiments, the nonwoven fiber web comprises short glass fibers (which may have an average fiber diameter within one or more of the above ranges) and comprises at least some of the short glass fibers having a diameter less than or equal to 15 microns, less than or equal to 14 microns, less than or equal to 13 microns, less than or equal to 12 microns, less than or equal to 11 microns, less than or equal to 10 microns, less than or equal to 9 microns, less than or equal to 8 microns, less than or equal to 7 microns, less than or equal to 6 microns, less than or equal to 5 microns, less than or equal to 4 microns, less than or equal to 3 microns, less than or equal to 2 microns, less than or equal to 1.5 microns, less than or equal to 1 micron, less than or equal to 0.9 microns, less than or equal to 0.8 microns, less than or equal to 0.7 microns, less than or equal to 0.6 microns, or less than or equal to 0.5 microns. Combinations of these ranges are also possible (e.g., greater than or equal to 0.3 microns and less than or equal to 15 microns, greater than or equal to 0.3 microns and less than or equal to 4 microns, greater than or equal to 7 microns and less than or equal to 15 microns, or greater than or equal to 3 microns and less than or equal to 11 microns). Other ranges are also possible.

[0068] The nonwoven webs described herein may include short glass fibers having any of a variety of suitable lengths. In some embodiments, the nonwoven webs include short glass fibers having an average length of greater than or equal to 0.5 mm, greater than or equal to 0.6 mm, greater than or equal to 0.7 mm, greater than or equal to 0.8 mm, greater than or equal to 0.9 mm, greater than or equal to 1 mm, greater than or equal to 1.2 mm, greater than or equal to 1.5 mm, greater than or equal to 1.7 mm, greater than or equal to 2 mm, greater than or equal to 2.2 mm, greater than or equal to 2.5 mm, or greater than or equal to 2.8 mm. In some embodiments, the nonwoven webs include short glass fibers having an average length of less than or equal to 3 mm, less than or equal to 2.8 mm, less than or equal to 2.5 mm, less than or equal to 2.2 mm, less than or equal to 2 mm, less than or equal to 1.8 mm, less than or equal to 1.5 mm, less than or equal to 1 mm, less than or equal to 0.9 mm, less than or equal to 0.8 mm, less than or equal to 0.7 mm, or less than or equal to 0.6 mm. Combinations of these ranges are also possible (e.g., greater than or equal to 0.5 mm and less than or equal to 3 mm, greater than or equal to 1 mm and less than or equal to 2.5 mm, greater than or equal to 1.2 mm and less than or equal to 2.2 mm, or greater than or equal to 1.5 mm and less than or equal to 2 mm). Other ranges are also possible.

[0069] In some embodiments, the nonwoven web comprises short glass fibers that are microglass fibers. Thus, the microglass fibers (when present) may have some or all of the properties described above for the short fibers (e.g., weight %, average length relative to the total weight of the nonwoven web). The nonwoven web may also comprise short glass fibers that are not microglass fibers (in addition to and / or in place of the short glass fibers that are microglass fibers). In some embodiments, the nonwoven web comprises microglass fibers at a weight percentage of greater than or equal to 0 wt%, greater than or equal to 25 wt%, greater than or equal to 50 wt%, or greater than or equal to 75 wt%, relative to the total weight of the short glass fibers in the nonwoven web. In some embodiments, the nonwoven web comprises microglass fibers at a weight percentage of less than or equal to 100 wt%, less than or equal to 75 wt%, less than or equal to 50 wt%, or less than or equal to 25 wt%, relative to the total weight of the short glass fibers in the nonwoven web. Combinations of these ranges are also possible (e.g., greater than or equal to 0 wt % and less than or equal to 100 wt %). Other ranges are also possible. In some embodiments, the microglass fibers account for 0 wt % of the short glass fibers in the nonwoven web. In some embodiments, the microglass fibers account for 100 wt % of the short glass fibers in the nonwoven web.

[0070] Microglass fibers can have various suitable compositions. For example, the nonwoven web can include microglass fibers that are high softening point fibers and / or microglass fibers that are not high softening point fibers. Non-limiting examples of short glass fibers include B glass fibers, E glass fibers, S glass fibers, M glass fibers, C glass fibers (e.g., Lauscha C glass fibers, JM 253C glass fibers) on page 45 according to Man Made Vitreous Fibers by Nomenclature Committee of TIMA Inc., March 1993, and non-persistent glass fibers (e.g., fibers that are configured to completely dissolve in the fluid present in human lungs in less than or equal to 40 days, such as Johns Manville 481 fibers).

[0071] As described above, microglass fibers suitable for inclusion in the nonwoven webs described herein are a type of short glass fibers. Thus, they can have an average length and include fibers having diameters within some or all of the ranges described above for the average length of short glass fibers. Microglass fibers are generally relatively thin and thus can have an average diameter within some or all of the ranges described above for the average diameter of short glass fibers having an upper limit of less than or equal to 5 microns.

[0072] The present disclosure recognizes the advantages of including other fibers besides glass fibers in a nonwoven web suitable for use as a thermal insulation material. Additional fibers can provide many advantages, including improved processability of the nonwoven web and / or improved adhesion between glass fibers in the nonwoven web. Including additional fibers can, for example, improve the tensile strength, elongation at break and / or one or more other mechanical properties of the nonwoven web.

[0073] An example of additional fiber types is binder fiber. Various suitable types of binder fibers can be used in the nonwoven webs described herein. In some embodiments, the binder fiber includes multicomponent fibers. The multicomponent fibers may include bicomponent fibers (i.e., fibers comprising two components), and / or may include fibers comprising three or more components. The multicomponent fibers may have any one of various suitable structures. For example, the nonwoven web may include one or more of the following types of multicomponent fibers: core / sheath fibers (e.g., concentric core / sheath fibers, non-concentric core-sheath fibers), segmented pie-shaped fibers, parallel fibers, tip-trilobal fibers, and "island" fibers. The core-sheath bicomponent fibers may include a sheath having a melting temperature lower than the melting temperature of the core. When heated (e.g., during a bonding step), the sheath may melt before the core, thereby bonding the nonwoven web together while the core remains solid.

[0074] Non-limiting examples of suitable materials that can be included in the multicomponent binder fibers include poly(olefins), such as poly(ethylene), poly(propylene), and poly(butylene); poly(esters) and copoly(esters), such as poly(ethylene terephthalate) (e.g., amorphous poly(ethylene terephthalate)), copoly(ethylene terephthalate), poly(butylene terephthalate), and poly(ethylene isophthalate); poly(amides) and copoly(amides), such as nylon and aramid; and halogenated polymers, such as poly(tetrafluoroethylene). Suitable copoly(ethylene terephthalate)s can contain repeating units formed by polymerization of ethylene terephthalate monomers and also contain repeating units formed by polymerization of one or more comonomers. Such comonomers may include linear, cyclic and branched aliphatic dicarboxylic acids having 4 to 12 carbon atoms (e.g., succinic acid, glutaric acid, adipic acid, dodecanedioic acid and 1,4-cyclohexanedicarboxylic acid); aromatic dicarboxylic acids having 8 to 12 carbon atoms (e.g., isophthalic acid and 2,6-naphthalene dicarboxylic acid); linear, cyclic and branched aliphatic diols having 3 to 8 carbon atoms (e.g., 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butanediol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-propylene glycol, 2-methyl-1,3-propylene glycol and 1,4-cyclohexanediol); and / or aliphatic and aromatic / aliphatic ether diols having 4 to 10 carbon atoms (e.g., hydroquinone bis(2-hydroxyethyl) ether and poly(vinyl ether) glycols having a molecular weight of less than 460 g / mol, such as diethylene glycol). ether glycol)).

[0075] Non-limiting examples of suitable material pairs that can be included in the bicomponent fiber include poly(ethylene) / poly(ethylene terephthalate), poly(propylene) / poly(ethylene terephthalate), copoly(ethylene terephthalate) / poly(ethylene terephthalate), poly(butylene terephthalate) / poly(ethylene terephthalate), copoly(amide) / poly(amide), and poly(ethylene) / poly(propylene). In the foregoing list, the material with the lower melting temperature is listed first and the material with the higher melting temperature is listed second. A core-sheath bicomponent fiber comprising one of the above pairs can have a sheath comprising the first material and a core comprising the second material.

[0076] In embodiments where the nonwoven web comprises two or more types of bicomponent fibers, each type of bicomponent fiber may independently comprise one of the above-described pairs of materials.

[0077] The multi-component binder fibers described herein can have various suitable melting points and / or contain components having various suitable melting points. In some embodiments, the nonwoven web contains multi-component fibers (e.g., bi-component fibers) containing components having a melting point of 80°C or greater, 90°C or greater, 100°C or greater, 110°C or greater, 120°C or greater, 130°C or greater, 140°C or greater, 150°C or greater, 160°C or greater, 170°C or greater, 180°C or greater, 190°C or greater, 200°C or greater, 210°C or greater, 220°C or greater, 230°C or greater, 240°C or greater, or 250°C or greater. In some embodiments, the nonwoven web comprises a multicomponent fiber (e.g., a bicomponent fiber) comprising a component having a melting point of less than or equal to 260°C, less than or equal to 250°C, less than or equal to 240°C, less than or equal to 230°C, less than or equal to 220°C, less than or equal to 210°C, less than or equal to 200°C, less than or equal to 190°C, less than or equal to 180°C, less than or equal to 170°C, less than or equal to 160°C, less than or equal to 150°C, less than or equal to 140°C, less than or equal to 130°C, less than or equal to 120°C, less than or equal to 110°C, less than or equal to 100°C, or less than or equal to 90°C. Combinations of the above referenced ranges are also possible (e.g., greater than or equal to 80°C and less than or equal to 260°C, or greater than or equal to 110°C and less than or equal to 230°C). Other ranges are also possible.

[0078] The melting points of the components of the multicomponent fiber can be determined by performing differential scanning calorimetry. Differential scanning calorimetry measurements can be performed by heating the multicomponent fiber to 300°C at 20°C / minute, cooling the multicomponent fiber to room temperature, and then determining the melting point during reheating to 300°C at 20°C / minute.

[0079] The nonwoven webs described herein may contain multicomponent fibers in any of a variety of suitable amounts. In some embodiments, the nonwoven web contains multicomponent fibers (e.g., bicomponent fibers) in an amount of greater than or equal to 4 wt%, greater than or equal to 5 wt%, greater than or equal to 6 wt%, greater than or equal to 7 wt%, greater than or equal to 8 wt%, greater than or equal to 9 wt%, greater than or equal to 10 wt%, greater than or equal to 11 wt%, greater than or equal to 12 wt%, or greater than or equal to 13 wt%, relative to the total weight of the nonwoven web. In some embodiments, the nonwoven web comprises multicomponent fibers (e.g., bicomponent fibers) in an amount of less than or equal to 20 wt%, less than or equal to 19 wt%, less than or equal to 18 wt%, less than or equal to 17 wt%, less than or equal to 16 wt%, less than or equal to 15 wt%, less than or equal to 14 wt%, less than or equal to 13 wt%, less than or equal to 12 wt%, less than or equal to 11 wt%, or less than or equal to 10 wt%, relative to the total weight of the nonwoven web. Combinations of these ranges are also possible (e.g., greater than or equal to 4 wt% and less than or equal to 20 wt%, greater than or equal to 6 wt% and less than or equal to 15 wt%, or greater than or equal to 8 wt% and less than or equal to 12 wt%, relative to the total weight of the nonwoven web). Other ranges are also possible.

[0080] The nonwoven webs described herein may include multicomponent fibers having any of a variety of suitable diameters. In some embodiments, the nonwoven webs include multicomponent fibers having an average fiber diameter greater than or equal to 3 microns, greater than or equal to 4 microns, greater than or equal to 5 microns, greater than or equal to 6 microns, greater than or equal to 7 microns, greater than or equal to 8 microns, greater than or equal to 9 microns, greater than or equal to 10 microns, greater than or equal to 11 microns, or greater than or equal to 12 microns (e.g., bicomponent fibers). In some embodiments, the nonwoven webs include multicomponent fibers having an average fiber diameter less than or equal to 18 microns, less than or equal to 17 microns, less than or equal to 16 microns, less than or equal to 15 microns, less than or equal to 14 microns, less than or equal to 13 microns, less than or equal to 12 microns, less than or equal to 11 microns, less than or equal to 10 microns, less than or equal to 9 microns, or less than or equal to 8 microns (e.g., bicomponent fibers). Combinations of these ranges are also possible (eg, greater than or equal to 3 microns and less than or equal to 18 microns, greater than or equal to 4 microns and less than or equal to 13 microns, or greater than or equal to 5 microns and less than or equal to 10 microns). Other ranges are also possible.

[0081] The nonwoven web described herein can include multi-component fibers with any one of various suitable lengths. In some embodiments, the nonwoven web includes multi-component fibers (e.g., bi-component fibers) having an average length of greater than or equal to 3 mm, greater than or equal to 4 mm, greater than or equal to 5 mm, greater than or equal to 6 mm, greater than or equal to 7 mm, greater than or equal to 8 mm, greater than or equal to 9 mm, or greater than or equal to 10 mm. In some embodiments, the nonwoven web includes multi-component fibers (e.g., bi-component fibers) having an average length of less than or equal to 15 mm, less than or equal to 14 mm, less than or equal to 13 mm, less than or equal to 12 mm, less than or equal to 11 mm, less than or equal to 10 mm, less than or equal to 9 mm, less than or equal to 8 mm, less than or equal to 7 mm, or less than or equal to 6 mm. The combination of these ranges is also possible (e.g., greater than or equal to 3 mm and less than or equal to 18 mm, greater than or equal to 4 mm and less than or equal to 13 mm, or greater than or equal to 5 mm and less than or equal to 10 mm). Other ranges are also possible.

[0082] Some nonwoven webs described herein comprise a combination of components causing the nonwoven web to have relatively low thermal conductivity and / or have the arrangement of the components. Such components can include specific fibers, such as those mentioned above. The arrangement of the relevant components can be that any relatively heat-conductive component is minimally connected and / or forms an arrangement of a relatively few networks spanning the thickness of the nonwoven web. The nonwoven web can also comprise non-fibrous components with relatively low thermal conductivity and / or reduce the thermal conductivity of the nonwoven web in an overall form. With respect to a nonwoven web having otherwise identical components without non-fibrous components, non-fibrous components are incorporated into the thermal conductivity that can reduce the nonwoven web as an additive.

[0083] A non-limiting example of such non-fiber components is aerogel. Some aerogels have low thermal conductivity, and incorporating them into a nonwoven web can further reduce the thermal conductivity of the nonwoven web. Aerogel can be a low-density porous material. In some embodiments, aerogel adopts the form of a porous solid (e.g., microporous solid), wherein a gas (e.g., air) is arranged in the hole. In some embodiments, aerogel is produced by extracting liquid from gel to produce a solid matrix. This can be achieved by supercritical drying and / or freeze drying. During or after liquid extraction, gas can penetrate into some or all of the positions where the liquid originally existed.

[0084] Any of a variety of suitable aerogels may be used. As one example, some aerogels comprise cross-linked macromolecular structures. As another example, some aerogels are ceramic. For example, some aerogels comprise inorganic oxides. Non-limiting examples of inorganic oxide aerogels are silica (SiO2) aerogels, silica hybrid aerogels (e.g., having the formula (SiO2) x (RSiO 1.5 ) y Silica hybrid aerogels, wherein R can be an alkyl group, such as methyl, ethyl, propyl, or butyl), titanium dioxide (TiO2) aerogels, and aluminum oxide (Al2O3) aerogels. Without wishing to be bound by any particular theory, it is believed that the aerogel having the formula (SiO2) x (RSiO 1.5 ) y The aerogel can advantageously be relatively hydrophobic and / or resist absorbing moisture from the air. In some embodiments, the aerogel includes two or more of the above-mentioned types of aerogels. Of course, it should be understood that these examples are non-limiting and other aerogels can be used.

[0085] The nonwoven webs described herein may contain aerogel in any of a variety of suitable amounts. In some embodiments, the nonwoven web contains aerogel in an amount greater than or equal to 0 wt%, greater than or equal to 5 wt%, greater than or equal to 10 wt%, greater than or equal to 15 wt%, greater than or equal to 20 wt%, greater than or equal to 25 wt%, greater than or equal to 30 wt%, greater than or equal to 35 wt%, or greater than or equal to 40 wt%, relative to the total weight of the nonwoven web. In some embodiments, the nonwoven web contains aerogel in an amount less than or equal to 50 wt%, less than or equal to 45 wt%, less than or equal to 40 wt%, less than or equal to 35 wt%, less than or equal to 30 wt%, or less than or equal to 25 wt%, relative to the total weight of the nonwoven web. Combinations of these ranges are also possible (e.g., greater than or equal to 0 wt % and less than or equal to 50 wt %, greater than or equal to 10 wt % and less than or equal to 50 wt %, greater than or equal to 15 wt % and less than or equal to 40 wt %, or greater than or equal to 20 wt % and less than or equal to 30 wt %, relative to the total weight of the nonwoven web). Other ranges are also possible. In some embodiments, aerogel accounts for 0 wt % of the nonwoven web (i.e., the nonwoven web does not contain aerogel).

[0086] The aerogels used in the nonwoven webs described herein can have relatively high stability at high temperatures. For example, the nonwoven webs described herein can include aerogels having any of a variety of suitable melting temperatures. In some embodiments, the nonwoven webs include aerogels having a melting temperature greater than or equal to 1,000°C, greater than or equal to 1,050°C, greater than or equal to 1,100°C, greater than or equal to 1,150°C, greater than or equal to 1,200°C, or greater than or equal to 1,250°C. In some embodiments, the nonwoven web comprises an aerogel having a melting temperature of less than or equal to 2,200°C, less than or equal to 2,100°C, less than or equal to 2,000°C, less than or equal to 1,900°C, less than or equal to 1,800°C, less than or equal to 1,700°C, less than or equal to 1,600°C, less than or equal to 1,500°C, less than or equal to 1,400°C, less than or equal to 1,300°C, or less than or equal to 1,200°C. Combinations of these ranges are also possible (e.g., greater than or equal to 1,000°C and less than or equal to 2,200°C). Other ranges are also possible. The melting point of the aerogel can be determined according to ASTM E794-2006.

[0087] The aerogels described herein can have a relatively high porosity. In some embodiments, the nonwoven web comprises an aerogel having a porosity greater than or equal to 90%, greater than or equal to 92%, greater than or equal to 95%, greater than or equal to 97%, greater than or equal to 97.5%, greater than or equal to 98%, greater than or equal to 98.5%, greater than or equal to 99%, or greater than or equal to 99.5%. In some embodiments, the nonwoven web comprises an aerogel having a porosity less than 100%, less than or equal to 99.9%, less than or equal to 99.5%, less than or equal to 99%, less than or equal to 98.5%, less than or equal to 98%, less than or equal to 97.5%, less than or equal to 97%, less than or equal to 95%, or less than or equal to 92%. Combinations of these ranges are also possible (e.g., greater than or equal to 90% and less than 100%, or greater than or equal to 97% and less than 100%). Other ranges are also possible. The porosity of aerogels can be determined according to ASTM D4284-2012.

[0088] Some aerogels have a relatively fine average pore size. In some embodiments, the nonwoven web comprises an aerogel having an average pore size of less than or equal to 150 nm, less than or equal to 125 nm, less than or equal to 100 nm, less than or equal to 90 nm, less than or equal to 80 nm, less than or equal to 70 nm, less than or equal to 60 nm, less than or equal to 50 nm, less than or equal to 40 nm, or less than or equal to 30 nm. In some embodiments, the nonwoven web comprises an aerogel having an average pore size greater than or equal to 0.5 nm, greater than or equal to 1 nm, greater than or equal to 2 nm, greater than or equal to 3 nm, greater than or equal to 4 nm, greater than or equal to 5 nm, greater than or equal to 8 nm, greater than or equal to 10 nm, greater than or equal to 15 nm, greater than or equal to 20 nm, greater than or equal to 30 nm, greater than or equal to 40 nm, greater than or equal to 50 nm, greater than or equal to 60 nm, greater than or equal to 70 nm, or greater than or equal to 80 nm. Combinations of these ranges are also possible (eg, greater than or equal to 0.5 nm and less than or equal to 150 nm). Other ranges are also possible. The average pore size of the aerogel can be determined according to ASTM D4284-2012.

[0089] In some embodiments, aerogels can have relatively low liquid water absorption. Such aerogels can advantageously retain relatively small amounts of water after being exposed to liquid water. In some embodiments, the liquid water absorption of aerogels is less than or equal to 100 wt%, less than or equal to 90 wt%, less than or equal to 75 wt%, less than or equal to 50 wt%, less than or equal to 25 wt%, less than or equal to 10 wt%, less than or equal to 5 wt%, less than or equal to 1 wt%, less than or equal to 0.5 wt%, or less than or equal to 0.1 wt%. In some embodiments, the liquid water absorption of aerogels is greater than or equal to 0 wt%, greater than or equal to 0.1 wt%, greater than or equal to 0.5 wt%, greater than or equal to 1 wt%, greater than or equal to 5 wt%, greater than or equal to 10 wt%, or greater than or equal to 25 wt%. Combinations of these ranges are also possible (e.g., greater than or equal to 0 wt% and less than or equal to 100 wt%). Other ranges are also possible. In some embodiments, the liquid water absorption of aerogels is 0 wt%. Liquid water absorption of an aerogel exposed to liquid water can be determined by ASTM C1511-15.

[0090] In some embodiments, aerogels can be configured to have relatively low water vapor absorption. Such aerogels can advantageously retain relatively small amounts of water after being exposed to water vapor. In some embodiments, the water vapor absorption of aerogels is less than or equal to 50% by weight, less than or equal to 40% by weight, less than or equal to 30% by weight, less than or equal to 25% by weight, less than or equal to 20% by weight, less than or equal to 15% by weight, less than or equal to 10% by weight, less than or equal to 5% by weight, less than or equal to 1% by weight, less than or equal to 0.5% by weight, or less than or equal to 0.1% by weight. In some embodiments, the water vapor absorption of aerogels is greater than or equal to 0% by weight, greater than or equal to 0.1% by weight, greater than or equal to 0.5% by weight, greater than or equal to 1% by weight, greater than or equal to 5% by weight, greater than or equal to 10% by weight, or greater than or equal to 25% by weight. Combinations of these ranges are also possible (e.g., greater than or equal to 0% by weight and less than or equal to 50% by weight). Other ranges are also possible. In some embodiments, the water vapor absorption of aerogels is 0% by weight. The water vapor absorption of aerogels can be determined by ASTM C1104-13A.

[0091] In some embodiments, the nonwoven web described herein may be capable of and / or configured to slow down and / or prevent the spread of combustion between electrochemical cells. This can be promoted by including one or more flame retardants. Flame retardants, when present, may be capable of and / or configured to undergo a chemical reaction when exposed to high temperatures. The chemical reaction may be suitable for slowing down and / or preventing the spread of combustion. Some flame retardants may be capable of and / or configured to release water and / or carbon dioxide when exposed to high temperatures. For example, flame retardants may be capable of and / or configured to release these compounds when experiencing thermal decomposition caused by exposure to high temperatures. In some embodiments, flame retardants undergo endothermic reactions when exposed to high temperatures. Endothermic reactions can consume heat and / or slow down the spread of combustion and / or heat in the battery.

[0092] Any of various flame retardants can be used in the nonwoven web described herein. For example, the flame retardant can be or include hydroxides (e.g., boron hydroxide, aluminum hydroxide, aluminum oxyhydroxide (AlOOH), calcium hydroxide, magnesium hydroxide), carbonates (e.g., calcium carbonate, magnesium carbonate), mineral materials that can release water and / or carbon dioxide when heated (e.g., vermiculite, kaolin, hydromagnesite, calcium carbonate and / or dolomite), organic halides (e.g., chlorides, bromides) and / or phosphorus-containing substances (e.g., disodium hydrogen phosphate, lithium iron phosphate, magnesium phosphate, sodium phosphate, diammonium phosphate and / or antimony phosphate). Of course, flame retardants are not limited to these classes of compounds, and other suitable flame retardants can be used.

[0093] The flame retardant can be incorporated into the nonwoven web in any of a variety of suitable forms. For example, in some embodiments, the flame retardant is incorporated as microparticles dispersed in the nonwoven web.

[0094] The nonwoven webs described herein may contain a flame retardant in any of a variety of suitable amounts. In some embodiments, the nonwoven web contains a flame retardant in an amount greater than or equal to 0 wt%, greater than or equal to 5 wt%, greater than or equal to 10 wt%, greater than or equal to 15 wt%, greater than or equal to 20 wt%, greater than or equal to 25 wt%, greater than or equal to 30 wt%, greater than or equal to 35 wt%, greater than or equal to 40 wt%, or greater than or equal to 45 wt%. In some embodiments, the nonwoven web contains a flame retardant in an amount less than or equal to 50 wt%, less than or equal to 45 wt%, less than or equal to 40 wt%, less than or equal to 35 wt%, or less than or equal to 30 wt%, relative to the total weight of the nonwoven web. Combinations of these ranges are also possible (e.g., greater than or equal to 0 wt % and less than or equal to 70 wt %, greater than or equal to 20 wt % and less than or equal to 50 wt %, greater than or equal to 15 wt % and less than or equal to 40 wt %, or greater than or equal to 20 wt % and less than or equal to 30 wt %, relative to the total weight of the nonwoven web). Other ranges are also possible. In some embodiments, the flame retardant comprises 0 wt % of the nonwoven web (i.e., the nonwoven web does not contain a flame retardant).

[0095] The flame retardants described herein can include particles having any of a variety of average diameters. In some embodiments, the flame retardant includes particles having an average diameter greater than or equal to 0.5 microns, greater than or equal to 0.6 microns, greater than or equal to 0.7 microns, greater than or equal to 0.8 microns, greater than or equal to 0.9 microns, greater than or equal to 1 micron, greater than or equal to 2 microns, greater than or equal to 5 microns, greater than or equal to 10 microns, greater than or equal to 15 microns, greater than or equal to 20 microns, greater than or equal to 25 microns, greater than or equal to 30 microns, greater than or equal to 35 microns, greater than or equal to 40 microns, greater than or equal to 45 microns, or greater than or equal to 50 microns. In some embodiments, the flame retardant comprises an average diameter of less than or equal to 100 microns, less than or equal to 95 microns, less than or equal to 90 microns, less than or equal to 85 microns, less than or equal to 80 microns, less than or equal to 75 microns, less than or equal to 70 microns, less than or equal to 65 microns, less than or equal to 60 microns, less than or equal to 55 microns, less than or equal to 50 microns, less than or equal to 45 microns, or less than or equal to 40 microns of particles. The combination of these ranges is also possible (for example, greater than or equal to 0.5 micron and less than or equal to 100 microns, greater than or equal to 1 micron and less than or equal to 95 microns, or greater than or equal to 5 microns and less than or equal to 80 microns). Other ranges are also possible. The average diameter of the particles can be determined according to ISO13320-2020.

[0096] In some embodiments, the nonwoven web is hydrophobic and / or comprises a hydrophobic component. Non-limiting examples of hydrophobic components include hydrophobic aerogels (as described elsewhere herein) and hydrophobic additives. Additional examples of hydrophobic components are described below.

[0097] Hydrophobic additives can account for relatively small amounts of nonwoven webs described herein when present. In some embodiments, hydrophobic additives account for less than or equal to 3 weight %, less than or equal to 2 weight %, less than or equal to 1 weight %, less than or equal to 0.75 weight %, less than or equal to 0.5 weight %, less than or equal to 0.2 weight %, or less than or equal to 0.1 weight % of nonwoven webs. In some embodiments, hydrophobic additives account for more than or equal to 0 weight %, more than or equal to 0.1 weight %, more than or equal to 0.2 weight %, more than or equal to 0.5 weight %, more than or equal to 0.75 weight %, more than or equal to 1 weight %, or more than or equal to 2 weight % of nonwoven webs. The combination of these ranges is also possible (e.g., less than or equal to 3 weight % and more than or equal to 0 weight %). Other ranges are also possible. In some embodiments, hydrophobic component accounts for 0 weight % of nonwoven webs (that is, nonwoven webs do not include hydrophobic component).

[0098] In some embodiments, the nonwoven web includes a hydrophobic additive that is a silane, a siloxane and / or an organosilicon. The non-limiting examples of such additives include alkylsilanes, fluoroalkylsilanes and organosilicones. The non-limiting examples of suitable alkylsilanes include n-octadecyltrihydroxysilane, n-octadecyltrichlorosilane and isobutyltrimethoxysilane. The non-limiting examples of suitable fluoroalkylsilanes include (tridecafluoro-1,1,2,2-tetrahydrooctyl)trichlorosilane, (3,3,3-trifluoropropyl)trichlorosilane and (heptadecafluoro-1,1,2,2-tetrahydrodecyl)trichlorosilane. The non-limiting examples of suitable organosilicon include methylhydrogensiloxane-dimethylsiloxane copolymer and poly (dimethylsiloxane).

[0099] In some embodiments, the nonwoven web comprises a fluorinated hydrophobic additive. The fluorinated hydrophobic additive may be in the form of a polymer or a non-polymer. For fluorinated polymer additives, the repeating unit may comprise at least one fluorine atom. Such polymers may be linear, branched, cyclic, saturated, and / or unsaturated.

[0100] In some cases, the nonwoven web comprises a highly fluorinated hydrophobic additive. For example, at least 30%, at least 50%, at least 70% or at least 90% of the hydrogen atoms of the hydrophobic additive can be replaced by fluorine atoms. Fluorinated hydrophobic additives can include, for example, at least 0.2:1, at least 0.5:1, at least 1:1, at least 2:1, at least 5:1 or at least 10:1 fluorine: hydrogen ratio. In some such embodiments, at least 30%, at least 50%, at least 70% or at least 90% of the fluorinated hydrophobic additive but less than 100% of the hydrogen atoms are replaced by fluorine atoms. In some embodiments, the hydrophobic additive is perfluorinated. Such a hydrophobic additive can include fluorine atoms, but does not include hydrogen atoms.

[0101] In some embodiments, the fluorinated hydrophobic additive comprises two oligomer (or polymer) components, including a fluorophilic component (e.g., component "A") and a hydrocarbon component (e.g., component "B"). These components can form a diblock copolymer (e.g., an "AB" structure) or other suitable structure. For example, the fluorophilic component can be a component described herein, and the hydrocarbon component can include, for example, an alkyl-containing or aromatic-containing component (including an acrylate-based or urethane-based component).

[0102] In some embodiments, the fluorine-loving component of the fluorinated hydrophobic additive or the fluorinated hydrophobic additive itself is a fluorinated oligomer or polymer. The fluorinated polymer can be a fluorocarbon polymer. In some embodiments, the fluorine-loving component of the fluorinated substance includes one or more fluorinated polymers, wherein the number of monomer units forming the fluorinated polymer is less than or equal to 10, less than or equal to 8, less than or equal to 6, less than or equal to 4, or less than or equal to 2. In certain embodiments, the fluorine-loving component is a component in which at least 30%, at least 50%, at least 70% or at least 90% of the hydrogen atoms of the fluorine-loving component are replaced by fluorine atoms. The fluorine-loving component can include, for example, a fluorine: hydrogen ratio of at least 0.2: 1, at least 0.5: 1, at least 1: 1, at least 2: 1, at least 5: 1 or at least 10: 1. In some cases, the fluorine-loving component is perfluorinated.

[0103] Non-limiting examples of types of fluorinated polymers or oligomers that may be included in the fluorinated hydrophilic additive (e.g., in the fluorophilic chain and / or as a side chain) include vinylidene fluoride (VDF), (per)fluoroolefins (e.g., tetrafluoroethylene (TFE)), chlorotrifluoroethylene (CTFE), (per)fluoroalkyl vinyl ethers (PAVE), such as CF2=CFOR f , where R f For (per)fluoroether or C n (Per)fluoroalkyl, such as trifluoromethyl or pentafluoropropyl, wherein n is an integer; and perfluoro-oxyalkyl vinyl ether CF2=CFOR x , wherein x is a C1-C12 perfluoro-oxyalkyl group having one or more ether groups, such as perfluoro-2-propoxy-propyl. Other examples of monomers present in the fluorinated species include fluorinated acrylates and fluorinated methacrylates.

[0104] In some embodiments, the fluorinated polymer may comprise a (per)fluoropolyether chain. The (per)fluoropolyether chain may comprise repeating units including, but not limited to: n F 2n O) x -, where n is an integer, for example -(C3F6O) x -、-(C4F8O) x -and-(C5F 10 O) x -;-(CF(CF3)CF2O) x -;-(CF2CF2O) x -;-(CF(CF3)CF2O) x -CF(CF3)CONH-;-(CF2(CF2) z’ CF2O) x -, where z' is an integer; -(CFLO) x-, where L = -F or -CF3; and -(CH2CF2CF2O) x -. In some cases, (C n F 2n+1 O) x -, where n is an integer (e.g., -(CF3O) x -、-(C2F5O) x -、-(C3F7O) x - etc.) are used as terminal groups and may not be polymerizable. In some cases, the (per)fluoropolyether chain may have (C n F m O) x -structure, wherein n and m are integers appropriately selected to form effective structures. In some embodiments, the fluorinated polymer comprises poly((per)fluoroformaldehyde), poly((per)fluoroethylene oxide), poly((per)fluoropropylene oxide) and / or poly((per)fluorobutylene oxide). In some embodiments, x in the above structure is less than or equal to 10. For example, x can be equal to 8, 6, 4, or 2.

[0105] In some embodiments, the nonwoven web comprises a hydrophobic additive that is a fluorocarbon polymer (also referred to as fluorocarbon). In one embodiment, the fluorocarbon polymer used is a fluoroacrylate copolymer emulsion comprising dipropylene glycol monomethyl ether. An example of a suitable fluorocarbon is Asahi Guard AG 955 (product code #930078) from LJ Specialties Limited (Enterprise Drive, Holmewood Industrial Park, Holmewood, Chesterfield, Derbyshire, S42 5UW UK). Another example of a suitable fluorocarbon is Repearl F-35 Fluorochemical from MIC Specialty Chemicals, Inc. (134 Mill Street, Tiverton, RI 02878). Another example of a suitable fluorocarbon is Phobol 8195 from Huntsman International, Textile Effects (4050 Premier Drive, High Point, NC 27265).

[0106] In some embodiments, the nonwoven web comprises a hydrophobic additive comprising a hydrophobic additive comprising a n F m R ywherein n is an integer greater than 1, m is an integer greater than 1, R is zero, an atom or a group of atoms (e.g., hydrogen, oxygen, sulfur, nitrogen, carbon, or a terminal group described herein), and y is an integer greater than or equal to 0. In some embodiments, n is an integer less than or equal to 8, and m is an integer greater than 1 (e.g., -C8F 15 H2, -C8F 16 H1, -C8F 17 ). In some embodiments, n is an integer less than or equal to 6, and m is an integer greater than 1. For example, in one particular embodiment, the chain comprises the formula -C6F 12 H1. In another embodiment, the chain comprises the formula -C6F 13 In some embodiments, n is an integer less than or equal to 4, and m is an integer greater than 1 (e.g., -C4F7H2, -C4F8H1, -C4F9). In some embodiments, the chain may include a n F 2n+1 In some embodiments, n is an integer greater than or equal to 6, and m is an integer greater than 1. n F m R y Such chains may be part of, for example, a fluoroacrylate polymer or other suitable polymer.

[0107] Further examples of the hydrophobic additive include poly(olefins) such as poly(propylene), waxes, paraffins, rosins, stearic acid-melamine water repellents, stearic acid esters, aldehyde-containing water repellents, sizing agents, and alkyl ketene dimers.

[0108] In some embodiments, the hydrophobic additive and / or the nonwoven web (e.g., comprising a hydrophobic additive) has a relatively high water contact angle. In some embodiments, the water contact angle of the hydrophobic additive and / or the nonwoven web is greater than or equal to 90°, greater than or equal to 100°, greater than or equal to 110°, greater than or equal to 120°, greater than or equal to 130°, greater than or equal to 140°, or greater than or equal to 150°. In some embodiments, the water contact angle of the hydrophobic additive and / or the nonwoven web is less than or equal to 180°, less than or equal to 170°, less than or equal to 160°, less than or equal to 150°, less than or equal to 140°, less than or equal to 130°, less than or equal to 120°, less than or equal to 110°, or less than or equal to 100°. Combinations of these ranges are also possible (e.g., greater than or equal to 90° and less than or equal to 180°). Other ranges are also possible. The water contact angle can be measured using standard ASTM D5946 (2009). The water contact angle is the angle between the surface of the hydrophobic additive at the triple point (solid, liquid and gas phases) and a tangent line drawn to the surface of the water drop when the drop rests on the substrate surface. A contact angle meter or goniometer can be used for this determination.

[0109] In some embodiments, the nonwoven web is resistant to shrinkage at elevated temperatures. For nonwoven webs used as thermal insulation materials, resistance to shrinkage at elevated temperatures can be advantageous because the shrinkage of the nonwoven web may reduce its ability to suppress the flow of heat between electrochemical cells, or may otherwise interfere with the flame retardant properties and / or insulating properties of the nonwoven web. The shrinkage of the nonwoven web at a specific temperature can be determined by the following procedure. First, the initial length of the nonwoven web in the relevant direction can be measured. Next, the nonwoven web can be placed in an oven set and balanced at the relevant temperature. The inside of the oven can include air that is communicated with the room temperature ambient air fluid outside the oven. The humidity of the ambient air outside the oven can be 45%. The nonwoven web can be retained in the oven for 10 minutes, then taken out and cooled to room temperature in room temperature air. Then, the final length of the nonwoven web in the relevant direction can be measured. Shrinkage in the relevant direction can be determined by applying the following formula using the length taken in the consistent direction: Shrinkage = [(initial length of nonwoven web - final length of nonwoven web) / initial length of nonwoven web]. The relevant direction can be the machine direction (MD) or the cross direction (CD), but shrinkage can also be measured in other directions.

[0110] In some embodiments, the nonwoven web experiences a shrinkage of less than or equal to 15%, less than or equal to 14%, less than or equal to 13%, less than or equal to 12%, less than or equal to 11%, less than or equal to 10%, less than or equal to 9%, less than or equal to 8%, less than or equal to 7%, less than or equal to 6%, less than or equal to 5%, or less than or equal to 4% when retained in an oven at 800° C. for 10 minutes. In some embodiments, the nonwoven web experiences a shrinkage of greater than or equal to 0%, greater than or equal to 0.5%, greater than or equal to 1%, greater than or equal to 1.5%, greater than or equal to 2%, greater than or equal to 2.5%, greater than or equal to 3%, greater than or equal to 4%, greater than or equal to 5%, greater than or equal to 6%, greater than or equal to 7%, greater than or equal to 8%, or greater than or equal to 9% when retained in an oven at 800° C. for 10 minutes. Combinations of these ranges are also possible (e.g., greater than or equal to 0% and less than or equal to 15%, greater than or equal to 0% and less than or equal to 10%, greater than or equal to 0.5% and less than or equal to 10%, greater than or equal to 0% and less than or equal to 2.5%, or greater than or equal to 0% and less than or equal to 10%). Other ranges are also possible.

[0111] In some embodiments, the shrinkage of the nonwoven fibrous web in the machine direction when kept in an oven at 800°C for 10 minutes is within one or more of the above ranges. In some embodiments, the shrinkage of the nonwoven fibrous web in the cross direction when kept in an oven at 800°C for 10 minutes is within one or more of the above ranges.

[0112] In some embodiments, the nonwoven web has a low thermal conductivity. In some embodiments, the thermal conductivity of the nonwoven web is less than or equal to 70 mW / mK, less than or equal to 65 mW / mK, less than or equal to 62 mW / mK, less than or equal to 60 mW / mK, less than or equal to 58 mW / mK, less than or equal to 55 mW / mK, less than or equal to 55 mW / mK, less than or equal to 52 mW / mK, less than or equal to 50 mW / mK, less than or equal to 48 mW / mK, less than or equal to 45 mW / mK, less than or equal to 42 mW / mK, less than or equal to 40 mW / mK, less than or equal to 38 mW / mK, or less than or equal to 35 mW / mK. In some embodiments, the thermal conductivity of the nonwoven fiber web is greater than or equal to 15mW / mK, greater than or equal to 18mW / mK, greater than or equal to 20mW / mK, greater than or equal to 22mW / mK, greater than or equal to 25mW / mK, greater than or equal to 28mW / mK, greater than or equal to 30mW / mK, greater than or equal to 32mW / mK, greater than or equal to 35mW / mK, greater than or equal to 38mW / mK, greater than or equal to 40mW / mK, or greater than or equal to 45mW / mK. Combinations of these ranges are also possible (e.g., greater than or equal to 15mW / mK and less than or equal to 70mW / mK, greater than or equal to 15mW / mK and less than or equal to 65mW / mK, greater than or equal to 15mW / mK and less than or equal to 55mW / mK, or greater than or equal to 15mW / mK and less than or equal to 45mW / mK). The thermal conductivity of the nonwoven web can be determined according to ASTM C518-21. Other ranges are possible.

[0113] In some embodiments, the thickness of the nonwoven web is less than or equal to 3.5 mm, less than or equal to 3.25 mm, less than or equal to 3 mm, less than or equal to 2.75 mm, less than or equal to 2.5 mm, less than or equal to 2.25 mm, less than or equal to 2 mm, less than or equal to 1.25 mm, less than or equal to 1.5 mm, or less than or equal to 1.25 mm. In some embodiments, the thickness of the nonwoven web is greater than or equal to 0.5 mm, greater than or equal to 0.75 mm, greater than or equal to 1 mm, greater than or equal to 1.25 mm, greater than or equal to 1.5 mm, greater than or equal to 1.75 mm, or greater than or equal to 2 mm. Combinations of these ranges are also possible (e.g., greater than or equal to 0.5 mm and less than or equal to 3.5 mm, greater than or equal to 0.75 mm and less than or equal to 2.5 mm, or greater than or equal to 1 mm and less than or equal to 2 mm). Other ranges are also possible. The thickness of the nonwoven web may be determined according to EN 823 (2013) under an applied pressure of 1.4 kPa.

[0114] The nonwoven webs described herein can have various suitable basis weights. In some embodiments, the basis weight of the nonwoven web is less than or equal to 400 g / m 2 , less than or equal to 375g / m 2 , less than or equal to 350g / m 2 , less than or equal to 325g / m 2 , less than or equal to 300g / m 2 , less than or equal to 280g / m 2 , less than or equal to 260g / m 2 , less than or equal to 240g / m 2 , less than or equal to 220g / m 2 , less than or equal to 200g / m 2 , less than or equal to 180g / m 2 , less than or equal to 160g / m 2 , less than or equal to 140g / m 2 , or less than or equal to 120g / m 2 In some embodiments, the nonwoven web has a weight per unit area of ​​greater than or equal to 50 g / m 2 , greater than or equal to 60g / m 2 , greater than or equal to 70g / m 2 , greater than or equal to 80g / m 2 , greater than or equal to 90g / m 2 , greater than or equal to 100g / m 2 , greater than or equal to 120g / m 2 , greater than or equal to 140g / m 2 , greater than or equal to 160g / m 2 , greater than or equal to 180g / m 2 , greater than or equal to 200g / m 2 , greater than or equal to 220g / m 2 , greater than or equal to 240g / m 2 , greater than or equal to 260g / m 2 , greater than or equal to 280g / m 2 , greater than or equal to 300g / m 2 , or greater than or equal to 320g / m 2 Combinations of these ranges are also possible (e.g., greater than or equal to 50 g / m 2 And less than or equal to 400g / m 2 , greater than or equal to 60g / m 2 And less than or equal to 350g / m 2 , or greater than or equal to 70g / m2 And less than or equal to 280g / m 2 ). Other ranges are also possible. The weight per unit area of ​​the nonwoven web can be determined according to ISO 536:2012.

[0115] The nonwoven web can have any of a variety of suitable porosities. The porosity of the nonwoven web is equal to 100%-[the solidity of the nonwoven web]. The solidity of the nonwoven web is equal to the percentage of the interior of the nonwoven web occupied by solid material. A non-limiting method for determining the solidity of the nonwoven web is described in this paragraph, but other methods are also possible. The method described in this paragraph includes determining the unit area weight and thickness of the nonwoven web, and then applying the following formula: Solidity = [unit area weight of the nonwoven web / (density of the components forming the nonwoven web × thickness of the nonwoven web)] × 100%. The density of the components forming the nonwoven web is equal to the average density of the materials forming the components (e.g., fibers, particles, aerogels) of the nonwoven web, which is usually specified by the manufacturer of each material. The average density of the materials that form the components of the nonwoven web can be determined by: (1) determining the total volume of all components in the nonwoven web; and (2) dividing the total mass of all components in the nonwoven web by the total volume of all components in the nonwoven web. If the mass and density of each component in the nonwoven web are known, the volume of all components in the nonwoven web can be determined by: (1) for each type of component, dividing the total mass of the components in the nonwoven web by the density of the component; and (2) adding the volumes of each component. If the mass and density of each component in the nonwoven web are not known, the volume of all components in the nonwoven web can be determined based on the Archimedean principle.

[0116] In some embodiments, the porosity of the nonwoven web is greater than or equal to 88%, greater than or equal to 89%, greater than or equal to 90%, greater than or equal to 91%, greater than or equal to 92%, greater than or equal to 93%, greater than or equal to 94%, or greater than or equal to 95%. In some embodiments, the porosity of the nonwoven web is less than or equal to 97%, less than or equal to 96%, less than or equal to 95%, less than or equal to 94%, less than or equal to 93%, less than or equal to 92%, or less than or equal to 91%. Combinations of these ranges are also possible (e.g., greater than or equal to 88% and less than or equal to 97%, greater than or equal to 90% and less than or equal to 97%, or greater than or equal to 92% and less than or equal to 97%). Other ranges are also possible.

[0117] The nonwoven webs described herein can have various suitable tensile strength values. In some embodiments, the tensile strength in the longitudinal direction of the nonwoven web is greater than or equal to 0.5 lb / inch, greater than or equal to 0.8 lb / inch, greater than or equal to 1 lb / inch, greater than or equal to 1.2 lb / inch, greater than or equal to 1.5 lb / inch, greater than or equal to 1.8 lb / inch, greater than or equal to 2 lb / inch, greater than or equal to 2.2 lb / inch, greater than or equal to 2.5 lb / inch, greater than or equal to 2.8 lb / inch, or greater than or equal to 3 lb / inch. In some embodiments, the tensile strength in the longitudinal direction of the nonwoven web is less than or equal to 6 pounds / inch, less than or equal to 5.8 pounds / inch, less than or equal to 5.5 pounds / inch, less than or equal to 5.2 pounds / inch, less than or equal to 5 pounds / inch, less than or equal to 4.8 pounds / inch, less than or equal to 4.5 pounds / inch, less than or equal to 4.2 pounds / inch, less than or equal to 4 pounds / inch, less than or equal to 3.8 pounds / inch, or less than or equal to 3.5 pounds / inch. The combination of these ranges is also possible (for example, greater than or equal to 0.5 pounds / inch and less than or equal to 6 pounds / inch, greater than or equal to 1 pound / inch and less than or equal to 5 pounds / inch, or greater than or equal to 1.5 pounds / inch and less than or equal to 4 pounds / inch). Other ranges are also possible. The tensile strength in the longitudinal direction of the nonwoven web can be determined according to ASTM D5034-21.

[0118] In some embodiments, the tensile strength of the nonwoven web in the cross direction is greater than or equal to 0.5 lbs / inch, greater than or equal to 0.8 lbs / inch, greater than or equal to 1 lbs / inch, greater than or equal to 1.2 lbs / inch, greater than or equal to 1.5 lbs / inch, greater than or equal to 1.8 lbs / inch, greater than or equal to 2 lbs / inch, greater than or equal to 2.2 lbs / inch, greater than or equal to 2.5 lbs / inch, greater than or equal to 2.8 lbs / inch, or greater than or equal to 3 lbs / inch. In some embodiments, the tensile strength of the nonwoven web in the cross direction is less than or equal to 4 lbs / inch, less than or equal to 3.8 lbs / inch, or less than or equal to 3.5 lbs / inch, less than or equal to 3.2 lbs / inch, less than or equal to 3 lbs / inch, less than or equal to 2.8 lbs / inch, less than or equal to 2.5 lbs / inch, less than or equal to 2.2 lbs / inch, or less than or equal to 2 lbs / inch. Combinations of these ranges are also possible (e.g., greater than or equal to 0.5 lbs / inch and less than or equal to 4 lbs / inch, greater than or equal to 0.8 lbs / inch and less than or equal to 3 lbs / inch, or greater than or equal to 1 lbs / inch and less than or equal to 2 lbs / inch). Other ranges are also possible. The tensile strength of the nonwoven web in the transverse direction can be determined according to ASTM D5034-21.

[0119] The nonwoven webs described herein can have various suitable elongation at break values. In some embodiments, the nonwoven web has a longitudinal elongation at break of greater than or equal to 1%, greater than or equal to 1.2%, greater than or equal to 1.4%, greater than or equal to 1.6%, greater than or equal to 1.8%, greater than or equal to 2%, greater than or equal to 2.2%, greater than or equal to 2.4%, greater than or equal to 2.6%, greater than or equal to 2.8%, greater than or equal to 3%, greater than or equal to 3.2%, greater than or equal to 3.4%, greater than or equal to 3.6%, greater than or equal to 3.8%, greater than or equal to 4%, or greater than or equal to 4.2%. In some embodiments, the longitudinal elongation at break of the nonwoven web is less than or equal to 6%, less than or equal to 5.8%, less than or equal to 5.6%, less than or equal to 5.4%, less than or equal to 5.2%, less than or equal to 5%, less than or equal to 4.8%, less than or equal to 4.6%, less than or equal to 4.4%, less than or equal to 4.2%, less than or equal to 4%, less than or equal to 3.8%, less than or equal to 3.6%, less than or equal to 3.4%, less than or equal to 3.2%, or less than or equal to 3%. Combinations of these ranges are also possible (e.g., greater than or equal to 1% and less than or equal to 6%, greater than or equal to 2% and less than or equal to 5%, or greater than or equal to 3% and less than or equal to 4%). Other ranges are also possible. The longitudinal elongation at break of the nonwoven web can be determined according to ASTM D5034-21.

[0120] In some embodiments, the nonwoven web has an elongation at break in the cross direction of greater than, or equal to, 2%, greater than, or equal to, 2.2%, greater than, or equal to, 2.4%, greater than, or equal to, 2.6%, greater than, or equal to, 2.8%, greater than, or equal to, 3%, greater than, or equal to, 3.2%, greater than, or equal to, 3.4%, greater than, or equal to, 3.6%, greater than, or equal to, 3.8%, greater than, or equal to, 4%, greater than, or equal to, 4.2%, greater than, or equal to, 4.4%, greater than, or equal to, 4.6%, greater than, or equal to, 4.8%, greater than, or equal to, 5%, greater than, or equal to, 5.2%, or greater than, or equal to, 5.4%. In some embodiments, the cross-direction elongation at break of the nonwoven web is less than or equal to 9%, less than or equal to 8.8%, less than or equal to 8.6%, less than or equal to 8.4%, less than or equal to 8.2%, less than or equal to 8%, less than or equal to 7.8%, less than or equal to 7.6%, less than or equal to 7.4%, less than or equal to 7.2%, less than or equal to 7%, less than or equal to 6.8%, less than or equal to 6.6%, less than or equal to 6.4%, less than or equal to 6.2%, less than or equal to 6%, less than or equal to 5.8%, less than or equal to 5.6%, less than or equal to 5.4%, less than or equal to 5.2%, or less than or equal to 5%. Combinations of these ranges are also possible (e.g., greater than or equal to 2% and less than or equal to 9%, greater than or equal to 3% and less than or equal to 8%, or greater than or equal to 4% and less than or equal to 7%). Other ranges are also possible. The elongation at break in the cross direction of a nonwoven web may be determined according to ASTM D5034-21.

[0121] In some embodiments, the phase of the nonwoven web is manufactured by a wet-laid process. Typically, the wet-laid process involves mixing one or more types of fibers together; for example, a plurality of glass fibers may be mixed alone or with a plurality of synthetic fibers to provide a fiber slurry. The slurry may be, for example, a water-based slurry. In some embodiments, the fibers may be stored in various storage tanks, optionally individually or in combination, before being mixed together.

[0122] In some embodiments, each plurality of fibers can be mixed and pulped together in a separate container. As an example, a plurality of glass fibers can be mixed and pulped together in one container, and a plurality of synthetic fibers (e.g., multi-component fibers) can be stirred and pulped in a second container. Subsequently, a plurality of fibers can be combined together into a single fiber mixture. Appropriate fibers can be processed by a pulper before and / or after being mixed together. In some embodiments, the combination of fibers is processed by a pulper and / or a storage tank before being mixed together. It is understood that other components (e.g., additives) can also be introduced into the mixture. In addition, it should be understood that other combinations of fiber types can be used in fiber mixtures, such as the fiber types described herein.

[0123] The wet-laid web forming process may include applying a single dispersion (e.g., pulp) or slurry in a solvent (e.g., an aqueous solvent such as water) to a web conveyor in a paper machine (e.g., a Fourdrinier paper machine or a rotary former) to form a single nonwoven fibrous web supported by the web conveyor. During the above process, a vacuum may be continuously applied to the dispersion of fibers to remove the solvent from the fibers, thereby obtaining an article comprising a single nonwoven fibrous web. In some embodiments, a polymer resin may be applied to the article to impart favorable properties to the article (e.g., enhanced mechanical strength, etc.).

[0124] Any suitable method for producing the fiber slurry can be used. In some embodiments, additional additives are added to the slurry to facilitate processing. The temperature can also be adjusted to a suitable range, for example, 33°F to 100°F (e.g., 50°F to 85°F). In some cases, the temperature of the slurry is maintained. In some cases, the temperature is not actively adjusted.

[0125] In some embodiments, the wet-laid web process uses equipment similar to that in conventional papermaking processes, such as a hydraulic pulper, a former or a headbox, a dryer and / or an optional converter. In some cases, nonwoven webs can also be made with laboratory handsheet molds. As discussed above, slurry can be prepared in one or more pulpers. After the slurry is properly mixed in the pulper, the slurry can be pumped into the headbox, where the slurry may or may not be combined with other slurries. Other additives may or may not be added. The slurry can also be diluted with additional water to a final concentration of the fiber in a suitable range, such as about 0.1% by weight to 0.5% by weight.

[0126] In some cases, the pH of the slurry can be adjusted as desired. For example, the fibers of the slurry can be dispersed under acidic or neutral conditions.

[0127] Before the slurry is sent to the headbox, the slurry can optionally be passed through a centrifugal cleaner and / or a pressure screen to remove undesirable material (e.g., unfiberized material). The slurry may or may not be passed through additional equipment (e.g., a refiner or a deflaker) to further improve the dispersion of the fibers. For example, a deflaker can be used to smooth or remove lumps or protrusions that may appear at any point during the formation of the fiber slurry. The fibers can then be collected onto a screen or net at an appropriate rate using any suitable equipment (e.g., a Fourdrinier paper machine, a rotary former, or a tilted Fourdrinier paper machine).

[0128] As mentioned above, in some embodiments, the nonwoven web also includes aerogel, flame retardant and / or hydrophobic additive.Such a material can be incorporated into the nonwoven web during the process (e.g., wet-laid process) of forming the nonwoven web, and / or can be added to the nonwoven web after formation (e.g., after the wet-laid process).When using the former technology, aerogel, flame retardant and / or hydrophobic additive (and / or its precursor) can be incorporated into the wet-laid mixture as an additive (e.g., particle additive, non-particle additive).For example, particle aerogel, flame retardant and / or hydrophobic additive can be incorporated into the wet-laid mixture as an additive.When using the latter technology, aerogel, flame retardant and / or hydrophobic additive (and / or its precursor) can be infiltrated into the nonwoven web (e.g., in particle form, in non-particle form). In some embodiments, precursors to the aerogel, flame retardant, and / or hydrophobic additive react therein to form the aerogel and / or flame retardant after being incorporated into the nonwoven fiber web (and / or wet-laid mixture).

[0129] As mentioned above, in some embodiments, the nonwoven web that has been formed can be impregnated with an aerogel precursor. The non-limiting method of impregnating a nonwoven web with an aerogel can include the first step, wherein reagents are mixed to form an aerogel precursor, and the aerogel precursor is impregnated in the nonwoven web. Then, the nonwoven web can be chemically aged in an aging fluid, and the aging fluid can be or include a solvent identical to the aerogel precursor (for example, the aging fluid can be ethanol). During chemical aging, the aerogel precursor can undergo crosslinking to form a gel. Then, a supercritical fluid (for example, supercritical CO2) can be used to remove solvent and aging fluid (if different) from the nonwoven web. After removing the solvent (and aging fluid in some cases), the nonwoven web can be heat dried (for example, heat dried in air), thereby leaving aerogel in the nonwoven web.

[0130] The nonwoven web impregnated with the aerogel precursor may be aged in the aging fluid for any of a variety of suitable time periods. In some embodiments, the nonwoven web impregnated with the aerogel precursor is aged in the aging fluid for a period of greater than or equal to 6 hours, greater than or equal to 8 hours, greater than or equal to 10 hours, greater than or equal to 12 hours, greater than or equal to 14 hours, greater than or equal to 6 hours, greater than or equal to 6 hours, or greater than or equal to 16 hours. In some embodiments, the nonwoven web impregnated with the aerogel precursor is aged in the aging fluid for a period of less than or equal to 48 hours, less than or equal to 44 hours, less than or equal to 40 hours, less than or equal to 36 hours, less than or equal to 32 hours, less than or equal to 30 hours, less than or equal to 28 hours, less than or equal to 26 hours, less than or equal to 24 hours, less than or equal to 22 hours, less than or equal to 20 hours, less than or equal to 18 hours, less than or equal to 16 hours, less than or equal to 14 hours, less than or equal to 12 hours, or less than or equal to 10 hours. Combinations of these ranges are also possible (eg, greater than or equal to 6 hours and less than or equal to 48 hours). Other ranges are also possible.

[0131] Any of a variety of volume ratios of aging fluid to aerogel precursor may be used during aging. In some embodiments, the volume ratio of aging fluid to aerogel precursor is greater than or equal to 1:1, greater than or equal to 2:1, greater than or equal to 3:1, greater than or equal to 4:1, greater than or equal to 5:1, or greater than or equal to 6:1. In some embodiments, the volume ratio of aging fluid to aerogel precursor is less than or equal to 20:1, less than or equal to 15:1, less than or equal to 10:1, or less than or equal to 5:1. Combinations of these ranges are also possible (e.g., greater than or equal to 1:1 and less than or equal to 20:1). Other ranges are also possible.

[0132] The aged nonwoven web impregnated with aerogel precursor can be dried for any of various suitable time periods. In some embodiments, the nonwoven web is dried for a time period greater than or equal to 15 minutes, greater than or equal to 30 minutes, greater than or equal to 45 minutes, greater than or equal to 60 minutes, greater than or equal to 90 minutes, or greater than or equal to 2 hours. In some embodiments, the nonwoven web is dried for a time period less than or equal to 12 hours, less than or equal to 8 hours, less than or equal to 6 hours, less than or equal to 4 hours, less than or equal to 3 hours, or less than or equal to 2 hours. Combinations of these ranges are also possible (e.g., greater than or equal to 15 minutes and less than or equal to 12 minutes). Other ranges are also possible.

[0133] The aged nonwoven web impregnated with aerogel precursor can be dried at any of a variety of temperatures. In some embodiments, the nonwoven web is dried at a temperature of greater than or equal to 80°C, greater than or equal to 85°C, greater than or equal to 90°C, greater than or equal to 95°C, greater than or equal to 95°C, greater than or equal to 100°C, greater than or equal to 105°C, or greater than or equal to 110°C. In some embodiments, the nonwoven web is dried at a temperature of less than or equal to 130°C, less than or equal to 125°C, less than or equal to 120°C, less than or equal to 115°C, less than or equal to 110°C, or less than or equal to 105°C. Combinations of these ranges are also possible (e.g., greater than or equal to 80°C and less than or equal to 130°C). Other ranges are also possible.

[0134] Aerogel precursors may include one or more aerogel-forming agents that may react to form aerogels. In some embodiments, aerogel-forming agents may undergo a sol-gel reaction to form aerogels. As a first step, aerogel precursors may be converted into sols by reaction. Then, sols may react to form aerogels. As described above, aerogel precursors and / or sols may be introduced into nonwoven webs before the reaction to form aerogels, and / or fully formed aerogels may be introduced into nonwoven webs. In some embodiments, aerogel precursors and / or sols may be introduced into nonwoven webs while being dissolved and / or suspended in a solvent (e.g., ethanol).

[0135] The sol-gel reaction for forming the aerogel may include hydrolysis and / or cross-linking. The aerogel forming agent may be and / or include a compound having the formula M(OR) x A metal alkoxide, wherein M is Al, Si or Ti, and R is an alkyl group (e.g., methyl, ethyl, propyl, butyl). Typically, when M is Al, x=3; when M is Si, x=4; and when M is Ti, x=4. The aerogel-forming reagent can be and / or include a substance configured to react with the metal alkoxide, such as water. In a non-limiting example, the aerogel-forming reagent includes tetraethyl orthosilicate (TEOS) and water. In such an embodiment, the reaction of TEOS and water will produce a silica aerogel and ethanol. The reaction is schematically shown below:

[0136]

[0137] The above reaction can be carried out using an acidic catalyst or a basic catalyst.

[0138] As another non-limiting example, in some embodiments, the aerogel forming reagent includes tetraethyl orthosilicate (TEOS), alkyltriethoxysilane (RSi(OC2H5)3) and water. In the alkyltriethoxysilane, R can be an alkyl group (e.g., methyl, ethyl, propyl, and / or butyl). The reaction of TEOS, RSi(OC2H5)3 and water can be carried out using an acidic catalyst or a basic catalyst. The reaction of TEOS, RSi(OC2H5)3 and water can produce ethanol and a precipitate having the formula (SiO2) x (RSiO 1.5 ) y Silica hybrid aerogels.

[0139] The nonwoven web as described herein can be used for any of various suitable batteries. Typically, the battery includes a plurality of electrochemical cells, which include a first electrochemical cell and a second electrochemical cell. In each electrochemical cell, electrons can be transferred from a first battery plate (e.g., a negative battery plate) to a second battery plate (e.g., a positive battery plate) during discharge, and from a second battery plate to a first battery plate during charging. During each of these processes, positively charged ions can also flow through the electrochemical cell in a direction opposite to the direction of the electron flow. Each electrochemical cell can also include an electrolyte configured to transmit these ions. As described above, the battery described herein can also include a nonwoven web described herein between some electrochemical cell pairs. Such a nonwoven web can be particularly suitable for insulating electrochemical cells from each other.

[0140] In some embodiments, the battery described herein includes a plurality of lithium metal electrochemical cells and / or lithium ion electrochemical cells. In such embodiments, the lithium ions may be positive ions that are transported between electrodes during charge and discharge. Without wishing to be bound by any particular theory, it is believed that such batteries may be particularly susceptible to overheating during use, and therefore may particularly benefit from including thermal insulation provided by a nonwoven web as described herein.

[0141] Typically, the battery described herein includes a plurality of electrochemical cells and nonwoven webs. In some embodiments, the battery includes greater than or equal to 2, greater than or equal to 3, greater than or equal to 5, greater than or equal to 10, greater than or equal to 15, greater than or equal to 20, greater than or equal to 30, or greater than or equal to 50 electrochemical cells. In some embodiments, the battery includes less than or equal to 250, less than or equal to 225, less than or equal to 200, less than or equal to 175, less than or equal to 150, less than or equal to 125, less than or equal to 100, less than or equal to 75, less than or equal to 50, or less than or equal to 25 electrochemical cells. Combinations of these ranges are also possible (e.g., greater than or equal to 2 and less than or equal to 250, greater than or equal to 3 and less than or equal to 100, or greater than or equal to 5 and less than or equal to 1 electrochemical cell). Other ranges are also possible.

[0142] In some embodiments, at least some of the nearest neighbor electrochemical cell pairs in the battery are separated from each other by a nonwoven fiber mesh. In some embodiments, greater than or equal to 1%, greater than or equal to 5%, greater than or equal to 10%, greater than or equal to 20%, greater than or equal to 50%, greater than or equal to 80%, or greater than or equal to 90% of the nearest neighbor electrochemical cell pairs are separated from each other by a nonwoven fiber mesh. In some embodiments, less than or equal to 100%, less than or equal to 90%, less than or equal to 80%, or less than or equal to 50% of the nearest neighbor electrochemical cell pairs are separated from each other by a nonwoven fiber mesh. Combinations of these ranges are also possible (for example, greater than or equal to 1% and less than or equal to 100%, greater than or equal to 5% and less than or equal to 90%, or greater than or equal to 20% and less than or equal to 80% of the nearest neighbor electrochemical cell pairs are separated from each other by a nonwoven fiber mesh). Other ranges are also possible.

[0143] The following examples are intended to illustrate some embodiments of the present disclosure, but are not intended to exemplify the full scope of the present disclosure.

[0144] Example 1

[0145] This example describes the preparation and selected properties of several nonwoven webs.

[0146] The nonwoven web is manufactured by a wet-laid web forming process. First, the fibers to be included in the nonwoven web are dispersed in water to form a wet material. These fibers are short glass fibers, ECR-glass fibers, and synthetic bicomponent PE / PET binder fibers. Next, the wet material is transferred to a tank. Water is filtered out from the bottom of the tank to produce a wet nonwoven web. The wet nonwoven web is further filtered under vacuum and then placed on a photo dryer (photo drier) (surface temperature is 100° C.) for 2 hours to remove all remaining water. The dry nonwoven web is then placed in an oven containing air and kept in an oven at 150° C. for 3 minutes to activate the bicomponent fibers and bond the bicomponent fibers to the glass fibers. Five nonwoven webs (referred to herein as net 1, net 2, net 3, net 4, and net 5) are prepared, each containing different relative amounts of each fiber type. Table 1 provides the relative amount of each fiber type used in nets 1 to 5 and the average size selected.

[0147] Table 1: Composition and properties of nonwoven webs.

[0148]

[0149] Example 2

[0150] This example describes the shrinkage of the nonwoven web described in Example 1 when heated.

[0151] Two 100 mm x 100 mm samples were cut from each nonwoven web described in Example 1. Each sample was placed in an oven containing air that had been preheated to a temperature of 800° C. or 850° C. and kept there for 10 minutes. Each sample was then taken out of the oven and allowed to cool to room temperature in room temperature air. The dimensions of the sample were then measured again. In addition, the morphology of each sample was examined under a scanning electron microscope (SEM).

[0152] Table 2 shows the dimensions of each sample after heating. Webs 1 to 3, which contained only a small amount of ECR-glass fibers, lost dimensional integrity at 850°C and could not be measured. In general, the linear shrinkage of each nonwoven web was reduced by adding more ECR-glass fibers. Each sample experienced shrinkage after heating.

[0153] Table 2: Dimensions of nonwoven webs after heating. The initial dimensions of all webs were 100×100.

[0154]

[0155] The SEM images show that the shrinkage is caused by the softening of the short glass fibers (which then flow together and apparently lose their fibrous properties). Figures 4 to 5Representative SEM images of web 1 before and after heating to 800°C, respectively. Figure 6 to Figure 7 Representative SEM images of web 5 before and after heating to 850° C., respectively. Figure 5 The significant softening of the short glass fibers is depicted. Figure 7 Some evidence of softening is seen in the Figure 5, but in general, the morphology of the web 5 after heating is similar to that of Figure 6 The initial morphologies shown are relatively similar.

[0156] These results indicate that inclusion of high softening point fibers in an amount of at least 50 weight percent can significantly reduce shrinkage and prevent softening of the nonwoven web, and can advantageously increase the temperature at which the nonwoven web can function as an effective thermal insulation material for battery applications.

[0157] Example 3

[0158] This example describes the preparation and selected properties of several nonwoven webs.

[0159] First, the fibers to be included in the nonwoven web are dispersed in water to form a wet material. These fibers are short glass fibers, ECR-glass fibers and synthetic bicomponent PE / PET binder fibers. A paper machine is used to manufacture a nonwoven web by a wet web forming process. Five nonwoven webs (referred to herein as web 6, web 7, web 8, web 9 and web 10) are prepared. Table 3 provides the relative amount of each fiber type used in webs 6 to 10 and the average size selected, and lists the various characteristics of the nonwoven web.

[0160] Table 3: Composition and properties of nonwoven webs.

[0161]

[0162] Example 4

[0163] This example describes the shrinkage of the nonwoven web described in Example 3 after heating.

[0164] Samples were cut from each nonwoven web described in Example 3. Each sample was placed in an oven containing ambient air that had been preheated to a temperature of 800° C. and kept there for 10 minutes. Each sample was then removed from the oven and allowed to cool to room temperature in ambient air. The dimensions of the sample were then measured again.

[0165] Table 4 shows the dimensions of each sample after heating. Web 6, which contains only 10 wt% high softening point ECR-glass fibers, experiences shrinkage of 13.9% and 23.7% in the cross direction (CD) and machine direction (MD), respectively. On the other hand, Webs 7 to 10 contain 60 wt% high softening point ECR-glass fibers and experience shrinkage of less than or equal to 3% in both CD and MD.

[0166] Table 4: Initial dimensions of the nonwoven webs and final dimensions after heating.

[0167]

[0168] The SEM images show that the shrinkage is caused by the softening of the short glass fibers (which then flow together and apparently lose their fibrous properties). Figures 8 to 9 Representative SEM images of web 6 before and after heating to 800° C., respectively. Figure 10 to Figure 11 Representative SEM images of web 7 before and after heating to 800° C., respectively. Fig. 9 A significant softening is depicted. Fig.11 Minimal softening is depicted, and the morphology of the web 7 after heating is similar to Fig.10 The initial morphologies shown are relatively similar.

[0169] These results indicate that inclusion of high softening point fibers in an amount of at least 50 weight percent can significantly reduce shrinkage and prevent softening of the nonwoven web, and can advantageously increase the temperature at which the nonwoven web can function as an effective thermal insulation material for battery applications.

[0170] Although several embodiments of the present disclosure have been described and illustrated herein, a person of ordinary skill in the art will readily envision a variety of other ways and / or structures for performing the functions described herein and / or obtaining the results and / or one or more advantages described herein, and each such variation and / or modification is considered to be within the scope of the present disclosure. More generally, it will be readily understood by those skilled in the art that all parameters, dimensions, materials, and configurations described herein are intended to be exemplary, and actual parameters, dimensions, materials, and / or configurations will depend on the specific application of the teachings of the present disclosure. Those skilled in the art will recognize or be able to determine many equivalents of the specific embodiments of the disclosure described herein using only routine experiments. Therefore, it should be understood that the aforementioned embodiments are illustrated only by example, and within the scope of the appended claims and their equivalents, the present disclosure can be practiced in a manner other than that specifically described and claimed. The present disclosure relates to each individual feature, system, product, material, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials and / or methods is included within the scope of the present disclosure if such features, systems, articles, materials and / or methods are not inconsistent with each other.

[0171] Unless explicitly stated to the contrary, the indefinite articles "a" and "an" as used herein in the specification and in the claims should be understood to mean "at least one".

[0172] The phrase "and / or" as used herein in the specification and in the claims should be understood to mean "either or both" of the elements so connected, i.e., elements that are present in conjunction in some cases and separately in other cases. Unless expressly indicated to the contrary, other elements may optionally be present in addition to the elements specifically identified by the "and / or" clause, whether related or unrelated to those specifically identified. Thus, as a non-limiting example, when used in conjunction with open language such as "comprises / comprising", a reference to "A and / or B" may refer to A without B (optionally including elements other than B) in one embodiment; to B without A (optionally including elements other than A) in another embodiment; to both A and B (optionally including other elements) in yet another embodiment; and so on.

[0173] As used herein in the specification and in the claims, "or" should be understood to have the same meaning as "and / or" as defined above. For example, when separating items in a list, "or" or "and / or" should be understood to be inclusive, i.e., including at least one of a plurality of elements or a list of elements, but also including more than one thereof, and optionally including additional unlisted items. Only when the opposite term is clearly indicated, such as "only one" or "exactly one", or when used in a claim, "consisting of..." will refer to including exactly one element in a plurality of elements or a list of elements. Typically, when preceded by an exclusive term such as "any", "one of", "only one of", or "exactly one of", the term "or" as used herein should only be interpreted to represent an exclusive alternative (i.e., one or the other but not both). When used in a claim, "consisting essentially of..." should have its ordinary meaning as used in the field of patent law.

[0174] As used herein in the specification and in the claims, the phrase "at least one" when referring to a list of one or more elements should be understood to mean at least one element selected from any one or more elements in the list of elements, but not necessarily including at least one of the individual elements and each element specifically listed in the list of elements, and not excluding any combination of elements in the list of elements. This definition also allows that elements other than the elements specifically identified in the list of elements referred to by the phrase "at least one" may optionally be present, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, "at least one of A and B" (or equivalently, "at least one of A or B", or equivalently, "at least one of A and / or B") may refer, in one embodiment, to at least one A, optionally including more than one A, without B being present (and optionally including elements other than B); in another embodiment, to at least one B, optionally including more than one B, without A being present (and optionally including elements other than A); in yet another embodiment, to at least one A, optionally including more than one A, and at least one B, optionally including more than one B (and optionally including other elements); and so on.

[0175] As used herein, "wt%" is an abbreviation for weight percent. As used herein, "at%" is an abbreviation for atomic percent.

[0176] Some embodiments may be embodied as methods, of which various examples have been described. The actions performed as part of the methods may be ordered in any suitable manner. Thus, embodiments may be constructed in which the actions are performed in a different order than shown, may include actions that are different (e.g., more or less) than those described, and / or may involve performing some actions simultaneously, even though these actions are shown as being performed sequentially in the embodiments specifically described above.

[0177] The use of ordinal terms such as "first", "second", "third", etc. to modify claim elements in the claims does not itself mean any priority, precedence or order of one claim element relative to another claim element or the temporal order of the actions of performing the method, but is merely used as a mark to distinguish one claim element with a certain name from another element with the same name (but using ordinal terms), thereby distinguishing the claim elements.

[0178] In the claims and the foregoing specification, all transitional phrases such as "comprising," "including," "with," "having," "containing," "involving," "having," etc. shall be understood as open-ended, i.e., meaning including but not limited to. Only the transitional phrases "consisting of" and "consisting essentially of" shall be closed or semi-closed transitional phrases, respectively, as set forth in Section 2111.03 of the U.S. Patent Office Manual of Patent Examining Procedures.

Claims

1. A battery comprising: a plurality of electrochemical cells, the plurality of electrochemical cells comprising a first electrochemical cell and a second electrochemical cell; as well as a nonwoven web positioned between the first electrochemical cell and the second electrochemical cell, wherein: The nonwoven web comprises glass fibers; The glass fibers include high softening point fibers, and the high softening point fibers include less than or equal to 0.8 wt % Na2O and / or less than or equal to 0.8 wt % K2O; The high softening point fiber accounts for greater than or equal to 30 weight % of the glass fiber; The glass fibers comprise greater than 80% by weight of the nonwoven web; and The average length of the glass fibers is greater than or equal to 0.5 mm and less than or equal to 7 mm.

2. A battery comprising: a plurality of electrochemical cells, the plurality of electrochemical cells comprising a first electrochemical cell and a second electrochemical cell; as well as a wet-laid nonwoven fibrous web positioned between the first electrochemical cell and the second electrochemical cell, wherein: The nonwoven web comprises glass fibers; The glass fibers include high softening point fibers, the high softening point fibers including less than or equal to 0.8 wt % Na2O and / or less than or equal to 0.8 wt % K2O; and The high softening point fibers account for greater than or equal to 30 weight percent of the glass fibers; and The glass fibers comprise greater than 80 weight percent of the nonwoven web.

3. A battery comprising: A plurality of modules, wherein the plurality of modules include a first module and a second module; as well as a nonwoven web positioned between the first module and the second module, wherein: The nonwoven web comprises glass fibers; The glass fibers include high softening point fibers, and the high softening point fibers include less than or equal to 0.8 wt % Na2O and / or less than or equal to 0.8 wt % K2O; The high softening point fiber accounts for greater than or equal to 30 weight % of the glass fiber; The glass fibers comprise greater than 80% by weight of the nonwoven web; and The average length of the glass fibers is greater than or equal to 0.5 mm and less than or equal to 7 mm.

4. A battery comprising: A plurality of modules, wherein the plurality of modules include a first module and a second module; as well as a wet-laid nonwoven fibrous web positioned between the first module and the second module, wherein: The nonwoven web comprises glass fibers; The glass fibers include high softening point fibers, the high softening point fibers including less than or equal to 0.8 wt % Na2O and / or less than or equal to 0.8 wt % K2O; and The high softening point fibers account for greater than or equal to 30 weight percent of the glass fibers; and The glass fibers comprise greater than 80 weight percent of the nonwoven web.

5. The battery according to any one of claims 3 to 4, wherein each of the first module and the second module comprises a plurality of electrochemical cells.

6. A battery according to any preceding claim, wherein the total thickness of the nonwoven web is less than or equal to 3.5 mm.

7. The battery of any preceding claim, wherein the thermal conductivity of the nonwoven web is less than or equal to 70 mW / Km.

8. A battery according to any preceding claim, further comprising a flame retardant.

9. The battery of any preceding claim, wherein the flame retardant comprises a hydroxide, a carbonate, a phosphorus-containing compound, and / or an organic halide compound.

10. The battery of any preceding claim, wherein the flame retardant comprises boron hydroxide, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, minerals, disodium hydrogen phosphate, lithium iron phosphate, magnesium phosphate, sodium phosphate, diammonium phosphate, and / or antimony phosphate.

11. A battery according to any preceding claim, wherein the flame retardant releases water and / or carbon dioxide when exposed to heat.

12. A battery according to any preceding claim, further comprising an aerogel.

13. A battery according to any preceding claim, wherein the aerogel is a silica aerogel or a silica aerogel having the formula (SiO2) x (RSiO 1.5 ) y A silica hybrid aerogel wherein R is methyl, ethyl, propyl, and / or butyl.

14. The battery of any preceding claim, wherein the glass fibers comprise chopped strand glass fibers.

15. A battery according to any preceding claim, wherein the glass fibres comprise short glass fibres.

16. A battery according to any preceding claim, wherein the glass fibres comprise micro glass fibres.

17. The battery of any preceding claim, wherein the high softening point fibers comprise chopped strand glass fibers.

18. The battery of any preceding claim, wherein the glass fibers have an average diameter greater than or equal to 1 micron and less than or equal to 12 microns.

19. A battery according to any preceding claim, wherein K2O comprises less than or equal to 0.5 wt% of the high softening point fibers.

20. The battery of any preceding claim, wherein Na2O comprises less than or equal to 0.5 wt% of the high softening point fibers.

21. The battery of any preceding claim, wherein the nonwoven fibrous web further comprises multicomponent fibers.

22. A battery according to any preceding claim, wherein the multi-component fibres are bi-component fibres.

23. The battery of any preceding claim, wherein the nonwoven fiber web comprises greater than or equal to 4 weight percent and less than or equal to 20 weight percent multicomponent fibers.

24. The battery of any preceding claim, wherein the nonwoven fibrous web exhibits less than or equal to 15% shrinkage in the machine direction and less than or equal to 15% shrinkage in the transverse direction when retained in an 800°C oven for 10 minutes.

25. A battery according to any preceding claim, wherein the battery is a lithium ion battery.

26. The battery of any preceding claim, wherein the high softening point fibers have a softening point greater than or equal to 800°C.

Images