Compressed member for electrochemical device

A method for sealing a non-aqueous electrolyte secondary battery by using a sealing member, wherein the sealing member is obtained by crosslinking a crosslinkable composition containing a fluorine-containing elastomer containing a unit based on at least one crosslinkable group-containing monomer selected from the group consisting of a crosslinkable group-containing monomer (1) represented by the general formula (1):

• CX12═CF—Rf1—X2
• wherein each X1 independently represents H or F, Rf1 represents a fluorinated alkylene group or a fluorinated oxyalkylene group, and X2 represents I or Br;
• and each group has optionally an oxygen atom between two carbon atoms when each group has two or more carbon atoms, and each group has optionally an aromatic ring, and each group is linear or branched;
• and
• a crosslinkable group-containing monomer (2) represented by the general formula (2):
• CX32═CX3—Z1—CX3═CX32
• wherein each X3 independently represents H, F, an alkyl group or a fluorinated alkyl group, and Z1 represents an alkylene group, a fluorinated alkylene group, a cycloalkylene group, a fluorinated cycloalkylene group, an oxyalkylene group or a fluorinated oxyalkylene group;
• and each group has optionally an oxygen atom between two carbon atoms when each group has two or more carbon atoms, and each group has optionally an aromatic ring, and each group is linear or branched.