When minors travel accompanied by their parents, it is always necessary to carry ID cards for the minors, in order to enable filiation confirmation.
Whenever minors travel unaccompanied by their parents, it is mandatory to carry an authorization for the effect. This authorization should be in writing, dated and signed by the persons exercising parent power legally certified, conferring powers to accompany the minors to a third party properly identified. For further details and download of the minute draft of the authorization you may consult here.
I'll be driving during the journey. Will my driver's license be sufficient?
In case you are going to drive at destination, check if your driver's license is within the expiration date and if it is recognized by the country that you are going to visit. Some countries, may require the International Drivers' License, which is valid only for one year. In order to obtain it, seehere.
You should gather information about the local legislation and comply scrupulously with the applicable Law of the country you are traveling to. Many countries have mechanisms for immediate enforcement of sanctions in case of infractions.