Cooling and flame-retardant composition for a propulsion system of an electric or hybrid vehicle
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) R F -L-R H (I) in which R F is a perfluorinated or partially fluorinated group, R H 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.
1. 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 having a boiling point of greater than or equal to 50° C.;
(ii) at least one fire retardant represented by formula (I):
R F -L-R H (I),
in which,
R F is a perfluorinated or partially fluorinated group,
R H is a hydrocarbon-based group, and
L is a linker,
wherein the fire retardant is at least partially encapsulated in the composition.
2. The composition as claimed in claim 1 , wherein:
R F is a perfluorinated or partially fluorinated (C 1 -C 16 )alkyl group, optionally interrupted with one or two heteroatoms chosen from a nitrogen atom and an oxygen atom; and
R H is a (C 1 -C 15 )alkyl, or (C 2 -C 16 )alkenyl group, the group being optionally substituted with a (C 3 -C 6 )cycloalkyl, phenyl or benzyl group.
3. The composition as claimed in claim 1 , wherein L is chosen from the following divalent groups: —CH 2 —, —CH═CH—, —O—, —S— or —PO 4 —.
4. The composition as claimed in claim 1 , wherein the composition comprises between 0.5% and 40% by weight of the fire retardant, relative to the total weight of the composition.
5. The composition as claimed in claim 4 , wherein the fire retardant is totally encapsulated in the composition.
6. The composition as claimed in claim 1 , wherein the hydrocarbon-based fluid has a boiling point of between 50° C. and 350° C.
7. The composition as claimed in claim 1 , wherein the hydrocarbon-based fluid is totally saturated.
8. The composition as claimed in claim 1 , wherein the base oil has a kinematic viscosity ranging from 1.5 to 8 mm 2 /s, measured at 100° C. according to the standard ASTM D445.
9. The composition as claimed in claim 1 , wherein the base oil is chosen from synthetic oils, poly-α-olefins, or polyalkylene glycols obtained by polymerization or copolymerization of alkylene oxides comprising from 2 to 8 carbon atoms.
10. The composition as claimed in claim 1 , further comprising at least one additive chosen from friction modifiers, detergents, anti-wear additives, extreme-pressure additives, dispersants, antioxidants, pour-point improvers, antifoam agents, or mixtures thereof.
11. The composition as claimed in claim 1 , further comprising at least one free-radical inhibitor and/or at least one additional fire retardant.
12. The composition as claimed in claim 11 , wherein:
the free-radical inhibitor is chosen from compounds in the form of a pentavalent phosphorus of the phosphate or phosphazene family or in the form of a trivalent phosphorus of the phosphite family; and
the additional fire retardant is chosen from halogenated compounds other than fluoro compounds.
13. A method for giving ignition-resistance properties to a composition for cooling a propulsion system of an electric or hybrid vehicle, including at least one battery, comprising adding to the composition at least one fire retardant as defined in claim 1 , which is at least partially encapsulated in the composition.
14. The method as claimed in claim 13 , wherein the composition further comprises at least one free-radical inhibitor and/or at least one additional fire retardant.
15. The method as claimed in claim 13 , wherein the composition comprises between 0.5% and 40% by weight of the fire retardant, relative to the total weight of the composition.
16. A process for cooling and fire-protecting a battery of a propulsion system of an electric or hybrid vehicle, comprising contacting the battery with a composition as described in claim 1 .
17. The process as claimed in claim 16 , wherein contacting the battery comprises:
completely or partially immersing the battery in a static or circulating amount of the composition; or
injecting, jetting, misting, or spraying the composition on the battery using pressure or gravity.
18. The composition as claimed in claim 1 , wherein:
R F is a perfluorinated or partially fluorinated group including from 1 to 16 carbon atoms; and
R H is a hydrocarbon-based group including from 1 to 16 carbon atoms.
19. The composition as claimed in claim 1 , wherein the composition comprises between 3% and 10% by weight of the fire retardant, relative to the total weight of the composition.
20. The composition as claimed in claim 1 , wherein the hydrocarbon-based fluid has a boiling point of between 80° C. and 200° C.
21. The composition as claimed in claim 1 , wherein the hydrocarbon-based fluid comprises isoparaffins comprising from 14 to 18 carbon atoms.