Separator for electrochemical device, electrode for electrochemical device, and electrochemical device
View Patent ↗A separator for an electrochemical device of the present invention includes a porous film including: a filler; an organic binder; and at least one resin selected from resin A that has a melting point of 80 to 140° C. and resin B that absorbs a non-aqueous electrolyte and swells upon heating and whose swelling degree increases with increasing temperature, and the filler contains boehmite having a secondary particle structure in which primary particles are connected.
1. A separator for an electrochemical device comprising a porous film including:
a filler;
an organic binder; and
polyethylene,
wherein the porous film comprises:
a first separator layer that is porous and primarily contains the filler; and
a second separator layer comprised of a microporous film containing polyethylene; and
wherein the filler contains boehmite having a secondary particle structure in which primary particles having a particle size of 1/10 to ⅓ of a particle size of the secondary particle are intergrown and connected to each other; and
wherein the boehmite having a secondary particle structure has a static bulk density of 0.1 to 0.5 g/cm 3 .
2. The separator for an electrochemical device according to claim 1 ,
wherein the filler further contains plate-like particles.
3. The separator for an electrochemical device according to claim 1 ,
wherein the boehmite having a secondary particle structure accounts for 75 vol % or more of the total volume of the filler.
4. The separator for an electrochemical device according to claim 1 ,
wherein the separator has a porosity of 20 to 60%.
5. The separator for an electrochemical device according to claim 1 ,
wherein the separator has an average pore size of 0.01 to 0.3 μm.
6. The separator for an electrochemical device according to claim 1 ,
wherein the separator has a tortuosity factor of 3 or more.
7. The separator for an electrochemical device according to claim 1 ,
wherein
the first separator layer and the second separator layer are integrated together.
8. The separator for an electrochemical device according to claim 1 ,
wherein the first separator layer has a porosity of 10 to 50%, and a volume of the polyethylene contained in the second separator layer is 20% or more of the pore volume of the first separator layer.
9. The separator for an electrochemical device according to claim 1 , further comprising a porous substrate having a heat resistance temperature of 150° C. or higher.
10. The separator for an electrochemical device according to claim 9 ,
wherein the porous substrate is comprised of a fibrous material.
11. The separator for an electrochemical device according to claim 10 ,
wherein the fibrous material is comprised of at least one selected from the group consisting of cellulose, a modified form thereof, polyolefin, polyester, polyacrylonitrile, aramid, polyamide imide, polyimide, and inorganic oxide.
12. The separator for an electrochemical device according to claim 10 ,
wherein the fibrous material forms a woven fabric or non-woven fabric.
13. The separator for an electrochemical device according to claim 1 ,
wherein a Gurley value after heating to 150° C. is five times or more a Gurley value before heating.
14. The separator for an electrochemical device according to claim 1 ,
wherein the separator has a thickness of 30 μm or less.
15. An electrochemical device comprising a positive electrode, a negative electrode, a non-aqueous electrolyte, and a separator,
wherein the separator comprises the separator for an electrochemical device according to claim 1 .
16. An electrochemical device comprising a positive electrode, a negative electrode, a non-aqueous electrolyte, and a separator,
wherein the separator comprises: a first separator layer that is porous and primarily contains a filler; and
a second separator layer comprised of a microporous film primarily containing polyethylene,
the filler includes boehmite having a secondary particle structure in which primary particles having a particle size of 1/10 to ⅓ of a particle size of the secondary particle are intergrown and connected to each other; and
wherein the boehmite having a secondary particle structure has a static bulk density of 0.1 to 0.5 g/cm 3 ; and
the first separator layer is integrated with the positive electrode or the negative electrode.
17. An electrochemical device comprising a positive electrode, a negative electrode, a non-aqueous electrolyte, and a separator,
wherein the separator comprises the separator for an electrochemical device according to claim 7 .
18. The electrochemical device according to claim 16 , wherein the first separator layer and the second separator layer are overlaid within the electrochemical device to form the separator.