Patent ID: 7468222

Claim:
An electrochemical device comprising: a matrix including first and second electrodes; an electrolyte; and a shell for accommodating the matrix and the electrolyte in a closed state, wherein the shell includes first and second lids made of a metal opposing each other, and a gasket placed between the first and second lids; wherein the first and second lids and the gasket are arranged so as to define a space for accommodating the matrix; wherein at least one of the first and second lids is formed with a projection protruding toward the matrix so that the first lid and the first electrode electrically come into contact with each other and that the second lid and the second electrode electrically come into contact with each other, and the projection has a leading end part that is a flat part, at least one of the first and second lids contacts the matrix only at the leading end part of the projection formed on the one of the first and second lids; wherein the electrochemical device is formed by a placing step of placing the matrix within the shell; wherein the matrix, the gasket, and the first and second lids used in the placing step simultaneously satisfy conditions represented by the following expressions (1) and (2): T2>T1 (1), and T3>(T2−T1) (2) where T 1 is the thickness of the matrix, T 2 is the thickness of the gasket, and T 3 is the total height of the projection formed at the first lid and/or the second lid; and wherein the electrochemical device is rectangular.