Liqueur served by car fitted with working battery (10)

'liqueur' is the definition.

'car fitted with working battery' is the wordplay.
'car' becomes 'limo' (limo is a kind of car).
'fitted with' means one lot of letters goes inside another.
'working' becomes 'on' (on can mean working or activated).
'battery' becomes 'cell' (I've seen this in another clue).
'on'+'cell'='oncell'
'limo' placed around 'oncell' is 'LIMONCELLO'.

'served by' is the link.