| 摘要 |
<p>[Problem] There are provided a multi-layer piezoelectric element in which an external electrode plate can adapt itself to displacement of a stacked body successfully and development of cracks and occurrence of breaking in an electrically conducting bonding material can be suppressed, as well as to an injection device and a fuel injection system using the same. [Solution] The invention provides a multi-layer piezoelectric element including a stacked body (2) including piezoelectric layers (21) and internal electrode layers (22a, 22b), which are alternately stacked; an external electrode layer (3a, 3b) attached to a side surface of the stacked body (2), the external electrode layer being elongated in a stacking direction of the stacked body, the external electrode layer being electrically connected with ends of the internal electrode layers (22a, 22b) which are exposed on the side surface; and an external electrode plate (5a, 5b) bonded to the external electrode layer (3a, 3b) therealong by an electrically conducting bonding material (4). The external electrode plate (5a, 5b) is provided with slits (51) which extend from opposite long sides toward a center thereof in such a manner that tips of the respective slits overlap each other when viewed in the stacking direction of the stacked body (2), and a portion thereof where the tips of the respective slits (51) overlap each other is provided with a hole extending along an extension direction of the slit (51).</p> |
