DUAL-LAYER SEPARATOR FOR BATTERIES
Battery separators, and lead-acid batteries comprising battery separators, are generally provided. In some embodiments, the battery separators described herein have one or more features that enhance their suitability for various applications (e.g., lead-acid battery applications). In one embodiment, a battery separator described herein comprises at least two phases. In some cases, each phase may have a one or more features that result in a battery separator having enhanced physical properties. For example, the dual-phase battery separator may exhibit reduced electrical and ionic resistance, enhanced acid filling capacity, reduced acid stratification, and enhanced thermal and oxidative stability compared to conventional battery separators.
1 . A lead-acid battery, comprising:
battery plates; and
a battery separator, comprising:
a first phase and a second phase, wherein:
the first phase comprises fibers;
the second phase comprises fibers;
the first phase has a mean flow pore size of greater than or equal to 2 microns and less than or equal to 15 microns;
the second phase has a mean flow pore size of greater than or equal to 20 microns and less than or equal to 150 microns; and
the battery separator has an air permeability of greater than or equal to 3 CFM and less than or equal to 30 CFM.
2 . A battery separator, comprising:
a first phase and a second phase, wherein:
glass fibers make up greater than 40 wt % of the first phase;
glass fibers make up greater than 40 wt % of the second phase;
the first phase comprises fibers having an average fiber diameter of greater than or equal to 0.5 microns and less than or equal to 12 microns;
the second phase comprises fibers having an average fiber diameter of greater than or equal to 5 microns and less than or equal to 20 microns;
a ratio of the thickness of the second phase to the thickness of the first phase is greater than or equal to 1.15;
an acid-stable binder resin makes up greater than or equal to 2 wt % and less than or equal to 30 wt % of the battery separator; and
the battery separator has an air permeability of greater than or equal to 3 CFM and less than or equal to 30 CFM.
3 . A lead-acid battery as in claim 1 , wherein the first phase comprises fibers having an average fiber diameter of greater than or equal to microns and less than or equal to 12 microns.
4 . (canceled)
5 . A lead-acid battery as in claim 1 , wherein the second phase comprises fibers having an average fiber diameter of greater than or equal to 5 microns and less than or equal to 20 microns.
6 . (canceled)
7 . A lead-acid battery as in claim 1 , wherein the second phase comprises fibers having a larger average fiber diameter than the fibers in the first phase.
8 - 9 . (canceled)
10 . A lead-acid battery as in claim 1 , wherein a ratio of the thickness of the second phase to the thickness of the first phase is greater than or equal to 1.15.
11 - 12 . (canceled)
13 . A lead-acid battery as in claim 1 , wherein glass fibers make up greater than 40 wt % of the first phase.
14 . (canceled)
15 . A lead-acid battery as in claim 1 , wherein glass fibers make up greater than 40 wt % of the second phase.
16 . (canceled)
17 . A lead-acid battery as in claim 1 , wherein the first phase comprises glass fibers having an average fiber diameter of greater than or equal to 0.5 microns and less than or equal to 10 microns.
18 . A lead-acid battery as in claim 1 , wherein the second phase comprises glass fibers having an average fiber diameter of greater than or equal to 4 microns and less than or equal to 20 microns.
19 . (canceled)
20 . A lead-acid battery as in claim 1 , wherein synthetic fibers make up greater than 5 wt % and less than or equal to 45 wt % of the first phase and/or the second phase.
21 . (canceled)
22 . A lead-acid battery as in claim 1 , wherein the first phase and/or the second phase comprise synthetic fibers having an average fiber diameter of greater than or equal to 1 micron and less than or equal to 20 microns.
23 . (canceled)
24 . A lead-acid battery as in claim 20 , wherein the synthetic fibers comprise polyester.
25 . (canceled)
26 . A lead-acid battery as in claim 1 , wherein the battery separator further comprises a binder resin, and wherein the binder resin is an acid-stable binder resin.
27 . (canceled)
28 . A lead-acid battery as in claim 26 , wherein the binder resin comprises acrylic latex resin.
29 - 32 . (canceled)
33 . A lead-acid battery as in claim 26 , wherein the binder resin makes up greater than or equal to 2 wt % and less than or equal to 30 wt % of the battery separator.
34 . (canceled)
35 . A lead-acid battery as in claim 1 , wherein the battery separator has a puncture strength of greater than or equal to 6 N and less than or equal to 50 N.
36 . A lead-acid battery as in claim 1 , wherein the battery separator has an ionic resistance of greater than or equal to 20 mOhm·cm 2 and less than or equal to 200 mOhm·cm 2 .
37 - 40 . (canceled)
41 . A lead-acid battery as in claim 1 , wherein the battery separator has a mean flow pore size of greater than or equal to 3 microns and less than or equal to 30 microns.
42 - 44 . (canceled)
45 . A lead-acid battery as in claim 1 , wherein the first phase is formed on the top of the second phase during a wet-laid process.
46 - 54 . (canceled)