The ornamental design for battery for an unmannedaerialvehicle, as shown and described.
FIG. 1 is a perspective view showing my design;
FIG. 2 is a front view showing my design;
FIG. 3 is a rear view showing my design;
FIG. 4 is a left side view showing my design;
FIG. 5 is a right side view showing my design;
FIG. 6 is a top plan view showing my design; and,
FIG. 7 is a bottom plan view showing my design.
The broken lines in the drawings are for the purpose of illustrating portions of the battery for an unmanned aerial vehicle that form no part of the claimed design.