Cordless Hair Straightener

I am thinking of buying a cordless straightener, but I am not much familiar with these cordless products. I am from the Czech Republic and these straighteners are not available on the market, so no cells also... I am confused about the energy cell straighteners and battery straighteners . Can someone give me advice? Which one is better and why? Which one lasts longer? And can you recommend me a good straightener? I need a straightener that would be of use for let´s say 2 weeks without any electricity charging, as I will be travelling... Thanks for any help and advice