Hallo All, My wife will extend her visa end of this month. She has an elektronische aufenthaltstitel. During extension will she get a new card or they will just change the date on her existing card. the reason I am asking, if it is a new card it will take time to come and we are planning a vaccation in middle of next month for a week and will be back before her old visa expires. 

visa is issued at the consulate/embassy. It cannot be extended here. be clear in your question.
u meant residence permit ..I suppose
date is already printed on the card. new card will be issued. you can travel anywhere so long as the card is valid. beyond the date ..restricted within Germany

My wife had a similiar situation in July. She was given a 'fiktionsbescheinigung' (temporary residence permit) which is valid for a couple of months to allow the new residence permit card to arrive. In my wife's case we had to ask for this permit. Cost of this permit is 20 Euros.

My wife also asked the auslanderamt about travel restrictions. The lady in auslanderamt said that 'fiktionsbescheinigung' along with the expired residence permit is valid to travel back from home country to Germany, and within the schengen zone.

In your case, your wife's existing residence permit will still be valid when you come back, so you do not have to worry.