ELECTROCHEMICAL ENERGY STORAGE DEVICE

An electrochemical energy storage device comprises a cell (1), an electrolyte and a package (2). The electrochemical energy storage device further comprises a binding material (3) positioned between the cell (1) and the package (2). The binding material (3) comprises a first adhesive layer (31) and a second functional layer (32). The first adhesive layer (31) is directly or indirectly adhered and positioned on an outer surface of the cell (1); the second functional layer (32) is positioned on a side of the first adhesive layer (31) opposite to a surface of the first adhesive layer (31) directly or indirectly adhered on the cell (1), the second functional layer (32) is not adhered to the package (2) before a pressure is applied, and the second functional layer (32) is adhered to the package (2) after the pressure is applied.