Patent ID: 7859819

Claim:
An energy storage device ( 1 ) comprising several electric capacitors ( 2 , 3 , 4 ) enclosed in a capacitor housing ( 5 , 6 , 7 ) each provided with at least one electrical connector ( 8 - 13 ), an outer housing ( 16 ) enclosing an interior space ( 17 ) accommodating the several electric capacitors ( 2 , 3 , 4 ) each arranged in the outer housing ( 16 ), a body of a liquid ( 22 ) disposed in the outer housing ( 16 ) in heat exchange relationship with the capacitor housings ( 5 , 6 , 7 ), said body of liquid housing a boiling temperature below a predetermined maximum operating temperature of the electric capacitors ( 2 , 3 , 4 ) so that the liquid boils when the electric capacitors ( 2 , 3 , 4 ) are in operation, thereby forming vapors, a vapor condensation structure ( 28 ) for condensing the vapors to form condensate which is returned to the liquid body ( 22 ) surrounding the electric capacitors ( 2 , 3 , 4 ), vertically oriented evaporation chambers ( 18 , 19 , 20 , 21 ) are disposed at opposite sides of the electric capacitors ( 2 , 3 , 4 ).