potential difference is energy per unit charge passed I believe so when you have a circuit the voltage increases to rise the charge through the components and the higher the voltage increase the faster the current and the more energy is dissipated at certain components (a resistor), so meaning the more energy transferred the higher the potential difference, the other person I think means the current instead of the charge, if you have the CGP revision guide for edexcel its on the third page of P2 i believe.
Hope this helped!