You can use those IF AND ONLY IF the contacts are rated for the same current as the ESC AND IF you reduce the ESC speed to ZERO BEFORE switching the relay.
Absolutely. OP, make sure you take note of these requirements.
sorry @raschemmel but what are those "IF AND ONLY IF"? Can i buy it?
"If and only if" is a figure of speech, not a product. In order to meet the requirements rash mentioned, you need to incorporate it into your software and hardware design, not necessarily buying anything other than correctly rated relays.
I'd say your relays should be rated to at least 25A.
I can't tell if your relays are good enough from your pic (low resolution pic). You might want to get a prefabricated relay module. If not, you'll have to build your own driver circuit for the relay. Sainsmart relay modules are good, might want to look at their options.