Non-woven fabric and preparation method therefor, lithium battery diaphragm, and lithium battery diaphragm base membrane
A non-woven fabric and a preparation method therefore, a lithium battery diaphragm and a lithium battery diaphragm base membrane, relating to the field of materials. Raw materials of the non-woven fabric include main fibers and bonding fibers, wherein the bonding fibers include first bonding fibers and second bonding fibers; the melting point or softening point of the first bonding fibers is 120-220° C., and the melting point or softening point of the second bonding fibers is 100-170° C., the melting point or softening point of the second bonding fibers is at least 15° C. lower than that of the first bonding fibers; and the melting point or softening point of the main fibers is at least 20° C. higher than that of the first bonding fibers.
1 . A lithium battery separator base membrane, wherein the lithium battery separator base membrane comprises a non-woven fabric, wherein
a raw material for the non-woven fabric comprises a main fiber and a binder fiber, wherein the binder fiber comprises a first binder fiber and a second binder fiber; and
the first binder fiber has a melting point or softening point ranging from 120 to 220° C.; the second binder fiber has a melting point or softening point ranging from 100 to 170° C., and the melting point or softening point of the second binder fiber is lower than the melting point or softening point of the first binder fiber by 15° C. or more;
a melting point or softening point of the main fiber is higher than the melting point or softening point of the first binder fiber by 20° C. or more;
both the first binder fiber and the second binder fiber have a fiber length ranging from 1 to 6 mm, and both the first binder fiber and the second binder fiber have a fiber diameter less than or equal to 10 μm;
a fiber length of the main fiber ranges from 1 to 6 mm; and a fiber diameter of the main fiber is less than or equal to 4 μm;
the main fiber accounts for 60-80% of a total mass of the main fiber and the binder fiber;
the second binder fiber accounts for 10-40% of a total mass of the binder fiber;
a concave-convex structure is formed on the surface of the non-woven fabric; and wherein the non-woven fabric has a density of 0.50-0.9 g/cm 3 , an average pore size is less than or equal to 4.5 μm, and a ratio of a maximum pore size to the average pore size ranges from 1 to 10.
2 . The lithium battery separator base membrane according to claim 1 , wherein
the melting point or softening point of the second binder fiber is lower than the melting point or softening point of the first binder fiber by 20 to 100° C.
3 . The lithium battery separator base membrane according to claim 1 , wherein materials for the main fiber comprise at least one from polyester fiber, polyolefin fiber, polyamide fiber, polyimide fiber, polytetrafluoroethylene fiber, polyphenylene sulfide fiber, polyether ether ketone fiber, polyacrylonitrile fiber, polycarbonate fiber, and aramid fiber.
4 . The lithium battery separator base membrane according to claim 1 , wherein the main fiber accounts for 65-75% of the total mass of the main fiber and the binder fiber.
5 . The lithium battery separator base membrane according to claim 1 , wherein the second binder fiber accounts for 20-30% of the total mass of the binder fiber.
6 . The lithium battery separator base membrane according to claim 3 , wherein materials for the first binder fiber comprise at least one from undrawn polyester fiber, polyvinylidene fluoride fiber, polyamide fiber, copolyamide fiber, and polyolefin fiber; and
materials for the second binder fiber comprise at least one from polyolefin fiber, copolyester fiber, and copolyamide fiber.
7 . The concave-convex structure according to claim 1 , wherein a preparation process of the non-woven fabric comprises a hot-pressing treatment, and
during the hot-pressing process, the main fiber maintains a dimensional stability while the first binder fiber and the second binder fiber melt to bond the fibers to each other, upon cooling, the concave-convex structure of the non-woven fabric is formed.