ELECTROCHEMICAL DEVICE

PROBLEM TO BE SOLVED: To provide an electrochemical device capable of improving connection reliability.SOLUTION: An electrochemical device includes: a power generation element 20 formed by laminating electrode plates 21 and 25 including active material formation parts 21A and 25A and foil exposure parts 21B and 25B; collectors 30 and 31 having body parts 30A and 31A extending from external terminals 13 and 14 provided on a casing 11 housing the power generation element 20 and a plurality of connection pieces 30B and 31B extended from the body parts 30A and 31A along laminated parts of the foil exposure parts 21B and 25B; and a clip 35, which is a component separate from the collectors 30 and 31, having a pair of clamping piece parts 35A for clamping at least the laminated part of the foil exposure parts 21B and 25B in the thickness direction thereof and an advancing piece part 35B for dividing the laminated part of the foil exposure parts 21B an 25B in the thickness direction thereof and clamping it with the clamping piece parts 35A, and welded to the connection pieces 30B and 31B together with the laminated part of the foil exposure parts 21B and 25B.