I have read from various sources that, the photon strikes the solar cell and creates and electron hole pair which then migrates to their respective ends of the cells, this creates a potential difference from which we harness solar energy. Is there any limit to the maximum number of electron hole pairs that can be created in the cell? If not how are they renewed?
No, there is no limit, because electrons which leave the solar cell are replaced: an oversimplified way of thinking about it is that electrons migrate to one terminal and leave the device, while holes migrate to the other where they are filled by electrons pouring in from the terminal.
Solar cells do deteriorate over time, but the mechanism of this deterioration is different: it's because of slow chemical and structural changes I think (the same kind of process that eventually does for other semiconductors).
The photons raise the energy of the electrons which then pass their energy to a circuit, for example your appliance or the network. The electrons just circulate.