SEPARATOR INCLUDING POROUS COATING LAYER, METHOD FOR MANUFACTURING THE SEPARATOR AND ELECTROCHEMICAL DEVICE INCLUDING THE SEPARATOR

摘要

A separator includes a non-woven fabric substrate having pores, fine thermoplastic powder located inside the pores of the non-woven fabric substrate, and a porous coating layer disposed on at least one surface of the non-woven fabric substrate. The fine thermoplastic powder has an average diameter smaller than that of the pores and a melting point lower than the melting or decomposition point of the non-woven fabric substrate. The porous coating layer includes a mixture of inorganic particles and a binder polymer whose melting point is higher than the melting or decomposition point of the fine thermoplastic powder. In the porous coating layer, the inorganic particles are fixedly connected to each other by the binder polymer and the pores are formed by interstitial volumes between the inorganic particles. Previous filling of the large pores of the non-woven fabric substrate with the fine thermoplastic powder makes the porous coating layer uniform.

主权项

1. A separator having a layered structure comprising;
(a) a non-woven fabric substrate having pores formed among microfibers constituting the non-woven fabric substrate, (b) fine thermoplastic powder filling the pores of the non-woven fabric substrate and having an average diameter smaller than that of the pores of the non-woven fabric substrate and a melting point lower than the melting point or decomposition point of the non-woven fabric substrate, and (c) a porous coating layer disposed on at least one surface of the non-woven fabric substrate whose pores are filled with the fine thermoplastic powder, and comprising a mixture of inorganic particles and at least one binder polymer whose melting point is higher than the melting point or decomposition point of the fine thermoplastic powder, the inorganic particles being fixedly connected to each other by the binder polymer and the pores of the coating layer being formed by interstitial volumes between the inorganic particles.