Artillery associated with assault (7)
I believe the answer is:
battery
I believe this is a double definition.
'artillery' is the first definition.
(I know that battery is a type of artillery)
'associated with assault' is the second definition.
(I've seen this before)
(Other definitions for battery that I've seen before include "Means of storing electric current" , "Source of charge" , "Electricity source" , "Group of cells (or guns)" , "Personal attack" .)