Porous membrane for a secondary battery and a secondary battery
Disclosed is a porous membrane used for a secondary battery, such as lithium-ion secondary battery, wherein strength is improved and break is difficult to occur while maintaining lithium-ion conductivity. The porous membrane for a secondary battery comprising a binder for the porous membrane and a nonconductive particle, wherein the binder for the porous membrane is a polymer particle having a hetero phase structure, in which internal layer is a polymer wherein vinyl monomer components are polymerized and outer layer is a polymer wherein monomer components containing a hydrophilic functional group are polymerized. The hydrophilic functional group is at least one selected from the group consisting sulfonic acid group, carboxyl group, hydroxyl group and epoxy group.
1. A porous membrane for a secondary battery comprising a binder for the porous membrane and a nonconductive particle,
wherein the binder for the porous membrane is a polymer particle having a hetero phase structure, in which internal layer is a polymer wherein vinyl monomer components are polymerized and outer layer is a polymer wherein monomer components containing a hydrophilic functional group are polymerized,
the nonconductive particle is different from the polymer particle,
the polymer of the internal layer and the polymer of the outer layer have a different chemical structure, and
the vinyl monomer components include at least any one of aliphatic vinyl monomer, (meth)acrylic acid ester monomer, amide group-containing (meth)acrylic monomer, multifunctional di(meth)acrylic monomer or aromatic vinyl monomer.
2. The porous membrane for a secondary battery as set forth in claim 1 , wherein the hydrophilic functional group is at least one selected from the group consisting of sulfonic acid group, carboxyl group, hydroxyl group and epoxy group.
3. The porous membrane for a secondary battery as set forth in claim 1 , wherein the outer layer is a polymer comprising a polymerization unit of (meth)acrylonitrile and that of (meth)acrylic acid esters.
4. A slurry of porous membrane for a secondary battery comprising a binder for the porous membrane, a nonconductive particle and a solvent,
wherein the binder for the porous membrane is a polymer particle having a hetero phase structure, in which internal layer is a polymer wherein vinyl monomer components are polymerized and outer layer is a polymer wherein monomer components containing a hydrophilic functional group are polymerized,
the nonconductive particle is different from the polymer particle,
the polymer of the internal layer and the polymer of the outer layer have a different chemical structure, and
the vinyl monomer components include at least any one of aliphatic vinyl monomer, (meth)acrlic acid ester monomer, amide group-containing (meth)acrlic monomer, multifunctional di(meth)acrylic monomer or aromatic vinyl monomer.
5. A manufacturing method of a porous membrane for a secondary battery comprising steps of:
coating a slurry of a porous membrane for a secondary battery comprising a binder for the porous membrane, a nonconductive particle and a solvent, wherein the binder for porous membrane is a polymer particle having a hetero phase structure, in which internal layer is a polymer wherein vinyl monomer components are polymerized and outer layer is a polymer wherein monomer components having a hydrophilic functional group are polymerized,
the nonconductive particle is different from the polymer particle,
the polymer of the internal layer and the polymer of the outer layer have a different chemical structure, and
the vinyl monomer components include at least any one of aliphatic vinyl monomer, (meth)acrylic acid ester monomer, amide group-containing (meth)acrylic monomer, multifunctional di(meth)acrylic monomer or aromatic vinyl monomer,
on a base material, and
drying the slurry coated base material.
6. A secondary battery electrode, wherein an electrode material mixture layer, comprising a binder for the electrode material mixture layer and an electrode active material, is adhered to a collector; and the porous membrane as set forth in claim 1 is on a surface of the electrode material mixture layer.
7. A separator for a secondary battery, wherein the porous membrane as set forth in claim 1 is on an organic separator.
8. A secondary battery comprising a positive electrode, a negative electrode, a separator and an electrolytic solution, wherein at least any one of the above positive electrode, negative electrode and separator has the porous membrane as set forth in claim 1 .
9. The porous membrane for a secondary battery as set forth in claim 2 , in which
a glass-transition temperature of the polymer of the internal layer is −60° C. or more to 20° C. or less and
a glass-transition temperature of the polymer of the outer layer is 0° C. or more.
10. A secondary battery electrode, wherein an electrode material mixture layer, comprising a binder for the electrode material mixture layer and an electrode active material, is adhered to a collector; and the porous membrane as set forth in claim 2 is on a surface of the electrode material mixture layer.
11. A separator for a secondary battery, wherein the porous membrane as set forth in claim 2 is on an organic separator.
12. A secondary battery comprising a positive electrode, a negative electrode, a separator and an electrolytic solution, wherein at least any one of the above positive electrode, negative electrode and separator has the porous membrane as set forth in claim 2 .
13. The porous membrane for a secondary battery as set forth in claim 1 , in which
a glass-transition temperature of the polymer of the internal layer is −60° C. or more to 20° C. or less and
a glass-transition temperature of the polymer of the outer layer is 0° C. or more.
14. A secondary battery electrode, wherein an electrode material mixture layer, comprising a binder for the electrode material mixture layer and an electrode active material, is adhered to a collector; and the porous membrane as set forth in claim 13 is on a surface of the electrode material mixture layer.
15. A separator for a secondary battery, wherein the porous membrane as set forth in claim 13 is on an organic separator.
16. A secondary battery comprising a positive electrode, a negative electrode, a separator and an electrolytic solution, wherein at least any one of the above positive electrode, negative electrode and separator has the porous membrane as set forth in claim 13 .