# US 2018/0026247 A1 · Multi-region battery separators > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0026247 A1 - Document ID: US20180026247A1 - Status: Published application - Kind: A1 - Application number: 15/642,588 - Filed: 2017-07-06 - Published: 2018-01-25 - Earliest claimed: 2014-09-15 - Assignees: Hollingsworth & Vose Company - Applicants: Hollingsworth & Vose Company - Inventors: Akshay Ashirgade; Zhiping Jiang - Web page: https://patentgrep.com/patent/US20180026247A1 ## CPC - H01M 50/44: Fibrous material - H01M 10/06: Lead-acid accumulators (semi-lead accumulators H01M10/20) - H01M 50/437: Glass - H01M 50/449: having a layered structure - H01M 50/457: comprising three or more layers - H01M 50/491: Porosity - H01M 50/494: Tensile strength - H01M 10/12: Construction or manufacture - H01M 50/403: Manufacturing processes of separators, membranes or diaphragms - H01M 50/446: Composite material consisting of a mixture of organic and inorganic materials - Y02E 60/10: Energy storage using batteries - Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract Disclosed is a battery separator, comprising two fiber regions comprising glass fibers, and a middle fiber region disposed between them comprising larger average diameter fibers and specified amounts of silica, or fine fibers, or both; and processes for making the separator. Also disclosed is a battery separator, comprising a fiber region and either one or two silica-containing region(s) adjacent thereto, each of the regions containing a specified amount of silica; and processes for making the separator. Such separators are useful, e.g., in lead-acid batteries. ## Claims ### Claim 1 A battery separator, comprising: a middle fiber region; a first peripheral fiber region; and a second peripheral fiber region; wherein the middle fiber region comprises fibers having an average diameter of greater than or equal to about 2 μm; and wherein each of the first and second peripheral fiber regions independently comprises glass fibers having an average diameter from about 0.1 to about 2 μm; provided that the average diameter of the fibers of the middle fiber region is larger than the average diameter of the fibers of each of the first and second peripheral fiber regions; wherein the middle fiber region is disposed between the first peripheral fiber region and the second peripheral fiber region; wherein the thickness of the middle fiber region constitutes 1-49% of the total fiber region thickness; and wherein the thickness of the first peripheral fiber region is different from the thickness of the second peripheral fiber region. ### Claim 2 (depends on 1) A lead-acid battery comprising a negative plate, a positive plate, and a battery separator according to claim 1, wherein the battery separator is disposed between the negative and positive plates. ### Claim 3 (depends on 1) The battery separator according to claim 1, wherein the middle fiber region comprises glass fibers having an average diameter from 2 to about 50 μm. ### Claim 4 (depends on 1) The battery separator according to claim 1, wherein the middle fiber region comprises fibers having an average diameter from about 3 to about 15 μm. ### Claim 5 (depends on 1) The battery separator according to claim 1, wherein the middle fiber region comprises glass fibers having an average diameter from about 3 to about 15 μm. ### Claim 6 (depends on 1) The battery separator according to claim 1, wherein each of the first and second peripheral fiber regions independently comprises glass fibers having an average diameter from about 0.4 to about 1.8 μm. ### Claim 7 (depends on 1) The battery separator according to claim 1, wherein the thickness of the middle fiber region constitutes 10-40% of the total fiber region thickness. ### Claim 8 (depends on 1) The battery separator according to claim 1, wherein the thickness of the middle fiber region constitutes 10-30% of the total fiber region thickness. ### Claim 9 (depends on 1) The battery separator according to claim 1, wherein the middle fiber region comprises from about 10 to about 30% by weight fibers having an average diameter from about 0.8 to about 1.6 μm. ### Claim 10 (depends on 1) The battery separator according to claim 1, wherein the middle fiber region comprises from about 2 to about 30% by weight silica. ### Claim 11 (depends on 1) The battery separator according to claim 1, wherein the average glass fiber diameter of the first peripheral fiber region differs from the average glass fiber diameter of the second peripheral fiber region by greater than or equal to 0.5 μm. ### Claim 12 (depends on 1) The battery separator according to claim 1, wherein the middle fiber region comprises from about 1 to 50% by weight fibers having an average diameter from about 0.1 to less than 2 μm, and wherein the tensile strength (machine direction) of the separator is about 2.00 to about 2.40 lbs/inch. ### Claim 13 (depends on 1) The battery separator according to claim 1, wherein the middle fiber region comprises from about 1 to 50% by weight fibers having an average diameter from about 0.1 to less than 2 μm, and wherein the tensile strength (cross direction) of the separator is about 1.75 to about 2.20 lbs/inch. ### Claim 14 (depends on 1) The battery separator according to claim 1, wherein the separator exhibits an acid filling time of about 30 to about 70 seconds. ### Claim 15 (depends on 1) The battery separator according to claim 1, wherein the separator exhibits an acid filling time of about 17 to about 50 seconds. ### Claim 16 (depends on 1) The battery separator according to claim 1, wherein the separator exhibits an acid stratification distance from about 2.5 to about 16 cm. ### Claim 17 (depends on 1) The battery separator according to claim 1, wherein the middle fiber region comprises from about 5 to about 50% by weight glass fibers having an average diameter from about 0.1 to less than 2 μm. ### Claim 18 (depends on 1) The battery separator according to claim 1, wherein the middle fiber region comprises from about 5 to about 50% by weight glass fibers having an average diameter from about 0.8 to about 1.6 μm. ### Claim 19 A battery separator, comprising: a middle fiber region; a first peripheral fiber region; and a second peripheral fiber region; wherein the middle fiber region comprises fibers having an average diameter of greater than or equal to about 2 μm; and wherein each of the first and second peripheral fiber regions independently comprises glass fibers having an average diameter from about 0.1 to about 2 μm; provided that the average diameter of the fibers of the middle fiber region is larger than the average diameter of the fibers of each of the first and second peripheral fiber regions; wherein the middle fiber region is disposed between the first peripheral fiber region and the second peripheral fiber region; wherein the thickness of the middle fiber region constitutes 1-49% of the total fiber region thickness; wherein the thickness of the first peripheral fiber region is different from the thickness of the second peripheral fiber region; and wherein formation of the battery separator involves a process comprising: (a) providing a first slurry of fibers having an average diameter from about 0.1 μm to about 2 μm; (b) laying down the first slurry on a wire of a papermaking machine; (c) providing a second slurry of fibers having an average diameter of greater than or equal to about 2 μm; (d) laying down the second slurry on top of the first slurry; and (e) dewatering the first and second slurries to form a 2-layer structure comprising the first peripheral region and at least a portion of the middle fiber region. ### Claim 20 A battery separator, comprising: a middle fiber region; a first peripheral fiber region; a second peripheral fiber region, wherein the first and second peripheral regions are different from the middle fiber region; means for the battery separator exhibiting an acid filling time of about 17 to about 155 seconds; and means for the battery separator exhibiting an acid stratification distance of from about 2.5 to about 16 cm.