The present invention relates to a composition for cooling a propulsion system of an electric or hybrid vehicle, comprising: (i) at least one base oil, or at least one hydrocarbon-based fluid with a boiling point of greater than or equal to 50° C.; and (ii) at least one fire retardant corresponding to formula (I) RF-L-RH  (I) in which RF is a perfluorinated or partially fluorinated group, RH is a hydrocarbon-based group, and L is a linker, said fire retardant of formula (I) being at least partially in an encapsulated form. The invention also relates to the use of at least one fire retardant of formula (I) which is at least partially in an encapsulated form in a composition for cooling a propulsion system of an electric or hybrid vehicle, including at least one battery, to give it ignition-resistance properties.
Finally, the invention relates to a process for cooling and fire-protecting a battery of a propulsion system of an electric or hybrid vehicle, comprising at least one step of placing at least one battery, in particular a lithium-ion or nickel-cadmium battery, in contact with a composition according to the invention.