Multi-layer piezoelectric element and piezoelectric actuator, injection device and fuel injection system including the same

摘要

There are provided a multi-layer piezoelectric element capable of suppressing the development of a small crack occurring at an interface between a piezoelectric layer and an internal electrode layer or in the internal electrode layer, and a piezoelectric actuator, an injection device and a fuel injection system including the same. A multi-layer piezoelectric element includes a stacked body in which piezoelectric layers and internal electrode layers are laminated, and an external electrode disposed on a side surface of the stacked body and electrically connected to the internal electrode layers through a conductive bonding material, the external electrode including protrusions protruding toward the stacked body.

主权项

1. A multi-layer piezoelectric element, comprising:
a stacked body in which piezoelectric layers and internal electrode layers are laminated; and an external electrode adhered to a side surface of the stacked body with a conductive bonding material and electrically connected to the internal electrode layers, wherein the external electrode includes at least one of a plurality of slits alternately extending from opposite ends of the external electrode in a width direction thereof toward a central part of the external electrode and a plurality of holes extending in the width direction of the external electrode, and protrusions which protrude toward the stacked body are disposed in peripheral edges of the slits or the holes, and a conductive layer electrically connected to the internal electrode layers is provided on a side surface of the stacked body, and each of the protrusions penetrates into the conductive layer and electrically connects the conductive layer.