The ornamental design for a piezoelectricelement, as shown and described.
FIG. 1 is a front view of a piezoelectric element of the present invention.
FIG. 2 is a rear view thereof.
FIG. 3 is a top plan view thereof.
FIG. 4 is a bottom view thereof.
FIG. 5 is a right side view thereof.
FIG. 6 is a left side view thereof.
FIG. 7 is a front perspective view thereof; and,
FIG. 8 is a rear perspective view thereof.
The broken lines depict unclaimed portions of the piezoelectric element, and thus form no part of the claimed design. The dot-dash chain lines depict boundaries of the claimed subject matter, and thus form no part of the claimed design.