FIG. 1 is a right side view of a portable power bank of my new design, according to a first embodiment;
FIG. 2 is a bottom view thereof;
FIG. 3 is a left side view thereof;
FIG. 4 is a top view thereof;
FIG. 5 is a front view thereof;
FIG. 6 is a rear view thereof;
FIG. 7 is a bottom, front, left side perspective view thereof;
FIG. 8 is a top, rear, right side perspective view thereof;
FIG. 9 is a right side view of a portable power bank of my new design, according to a second embodiment;
FIG. 10 is a bottom view thereof;
FIG. 11 is a left side view thereof;
FIG. 12 is a top view thereof;
FIG. 13 is a front view thereof;
FIG. 14 is a rear view thereof;
FIG. 15 is a bottom, front, left side perspective view thereof; and,
FIG. 16 is a top, rear, right side perspective view thereof.
The broken lines shown in the drawings illustrate portions of the portable power bank that form no part of the claimed design.