Panels that consist of 60 cells, electrically arranged in series can range from 200W of power output to over 350W of power output.

Because of the series arrangement of the cells, the output voltage for these panels will always be somewhere in the range of 37.5 volts open-circuit.  The reason for this is that each cell is capable of producing about 0.625 volts.  When you add all those cells in series, the resulting voltage is around 37.5 volts.  The number may change slightly from manufacturer to manufacturer based on their doping methods, testing methods, cell coatings, or even just specsmanship.

Why are there so many power ranges for 60 cell panels if their voltage is the same?

The answer takes into account many other factors, but one of the main factors is the cell size.  The larger the area of the cell, the more current it can produce.  Since power is Volts x Amps, the greater current means greater power output.  This is denoted by the Isc, or short-circuit current.

Panels that consist of 72 cells, electrically arranged in series can range from 300W of power output to over 500W of power output.  Panels, like the one below, are considered 72 cell panels from an electrical standpoint at their MC4 connectors, but are wired internally as 2-72 cell strings, i.e. 72S2P.  The reason for doing this is based largely on the manufacturing process.  If a large cell gets cracked during manufacture, it can be cut in half to save part of the product, then simply wired differently to produce the same end result as 72 cell full sized cell panel.

Because of the series arrangement of the cells, the output voltage for these panels will always be somewhere in the range of 45 volts open-circuit.  The reason for this is that each cell is capable of producing about 0.625 volts.  When you add all those cells in series, the resulting voltage is around 45 volts.  As cell sizes grow, the need to salvage as much of the individual cell as possible becomes more apparent and the salvage efforts can lower the cost of the overall panels.  As with the 60 cell panels, some additional reasons that there is such a range of power outputs in the 72 cell panels are cell efficiencies, sorting methods, and larger individual cell area.

Recently a newer class of panels has reached the market, 96 cell panels.  These panels help to overcome some of the nuances of building systems by raising the panel voltage and lowering the panel current.  As with the 60 cell and 72 cell panels, a 96 cell panel has atypical Voc of 0.625 * 96 = 60V.  The short circuit current is around 6A for a 350W panel.  With some newer installations the string voltage can be around 1500V, and so reaching that voltage can be accomplished in a smaller physical area than with 60 cell or 72 cell panels.

Bifacial solar modules offer many advantages over traditional solar panels. Power can be produced from both sides of a bifacial module, increasing total energy generation. They’re often more durable because both sides are UV resistant, and potential-induced degradation (PID) concerns are reduced when the bifacial module is frameless. 

Bifacial modules produce solar power from both sides of the panel. Whereas traditional opaque-backsheeted panels are monofacial, bifacial modules expose both the front and backside of the solar cells. When bifacial modules are installed on a highly reflective surface (like a white TPO roof or on the ground with light-colored stones), some bifacial module manufacturers claim up to a 30% increase in production just from the extra power generated from the rear.