 Another problem with Volta's batteries was short battery life (an hour's worth at best), which was caused by two phenomena.The first was that the current produced electrolysed the electrolyte solution, resulting in a film of hydrogen bubbles forming on the copper, which steadily increased the internal resistance of the battery (this effect, called "polarization", is counteracted in modern cells by additional measures).The other was a phenomenon called "local action", wherein minute short-circuits would form around impurities in the zinc, causing the zinc to degrade.