| 摘要 |
There are provided a multi-layer piezoelectric element which is capable of suppressing separation of an external electrode plate, as well as a piezoelectric actuator, an injection device, and a fuel injection system that are provided with the multi-layer piezoelectric element. A multi-layer piezoelectric element (1) of the invention includes a stacked body (4) composed of piezoelectric layers (2) and internal electrode layers (3) which are laminated; an external electrode plate (6) attached to a side face of the stacked body (4) via an electrically-conductive joining member (5); and a metal cover layer (7) being disposed on a surface of the external electrode plate (6), an area of the metal cover layer (7) corresponding to one end portion (4a) of the stacked body (4) in a stacking direction of the stacked body having a thick-walled portion (71) which is larger in thickness than an area of the metal cover layer corresponding to a midportion (4b) of the stacked body (4). |
