2oldman is correct.
https://www.altestore.com/blog/2016/04/how-do-i-read-specifications-of-my-solar-panel/#.YF1XItxME2wOpen Circuit Voltage (Voc)
Open circuit voltage is how many volts the solar panel outputs with no load on it. If you just measure with a voltmeter across the plus and minus leads, you will read Voc. Since the solar panel isn’t connected to anything, there is no load on it, and it is producing no current.
Maximum Power Point (Pmax)
The Pmax is the sweet spot of the solar panel power output, located at the “knee” of the curves in the graph above. It is where the combination of the volts and amps results in the highest wattage (Volts x Amps = Watts).
V of 22.5V nominal voltage of the panel--probably best to use MPPT controller with this. If the controller can tolerate a 45 volt input, I'd wire in series/parallel.
Isc short circuit current.