Separator for electrochemical element

Abstract

Disclosed herein is a separator for an electrochemical element, comprising a fibrous structure, wherein the fibrous structure has a first fibrous layer part in which short fibers and/or pulp-like fibers are intertwined with each other, and a second fibrous layer part; some of the short fibers and/or the pulp-like fibers constituting the first fibrous layer part penetrates the second fibrous layer part; and a pore diameter distribution of the fibrous structure satisfies the following formula: 0 μm<D max<18 μm, and 0 μm≤(D max−Dave)<13 μm, wherein D max is a maximum pore diameter (μm) of the fibrous structure, and Dave is an average pore diameter (μm) of the fibrous structure.

1 . A separator for an electrochemical element, comprising a fibrous structure,
 wherein the fibrous structure has a first fibrous layer part in which short fibers and/or pulp-like fibers are intertwined with each other, and a second fibrous layer part;   some of the short fibers and/or the pulp-like fibers constituting the first fibrous layer part penetrates the second fibrous layer part; and   a pore diameter distribution of the fibrous structure satisfies the following formula:
   0 μm< D  max<18 μm, and
 
   0 μm≤( D  max− D ave)<13 μm,
 
   wherein D max is a maximum pore diameter (μm) of the fibrous structure, and Dave is an average pore diameter (μm) of the fibrous structure.   
     
     
         2 . The separator for an electrochemical element according to  claim 1 , wherein a percentage by mass of the pulp-like fibers in relation to the constituent fibers of the first fibrous layer part is 10% by mass or more. 
     
     
         3 . The separator for an electrochemical element according to  claim 1 , wherein the pulp-like fibers are pulp-like fibers of an aramid resin. 
     
     
         4 . The separator for an electrochemical element according to  claim 1 , wherein the fibrous structure comprises particles. 
     
     
         5 . The separator for an electrochemical element according to  claim 2 , wherein the pulp-like fibers are pulp-like fibers of an aramid resin. 
     
     
         6 . The separator for an electrochemical element according to  claim 2 , wherein the fibrous structure comprises particles. 
     
     
         7 . The separator for an electrochemical element according to  claim 3 , wherein the fibrous structure comprises particles. 
     
     
         8 . The separator for an electrochemical element according to  claim 5 , wherein the fibrous structure comprises particles.