FR3140088A1 - Cooling of a battery by immersion in a composition with change of state - Google Patents

Abstract

The invention relates to the use of a heat transfer composition comprising from 20% to less than 100% by weight of a refrigerant comprising a compound chosen from halogenated hydrocarbons, perhalogenated compounds, fluorinated ketones, ethers fluorinated as well as combinations thereof, and more than 0% to 80% by weight of a dielectric fluid, for cooling a battery, the battery comprising energy storage cells immersed in the heat transfer composition, and the composition heat transfer undergoing evaporation in contact with the energy storage cells. Figure 1

Description

Cooling of a battery by immersion in a composition with change of state Field of the invention

The present invention relates to the use of a heat transfer composition comprising at least one refrigerant and at least one dielectric fluid, to cool a battery. The invention applies in particular to batteries for electric or hybrid vehicles.

Technical background

The need to dissipate strong thermal flows is essential in several applications, notably battery cooling. Liquid-vapor phase change cooling is an effective solution for dissipating significant amounts of heat while maintaining the battery temperature within its optimal temperature range and having a uniform system temperature.

In particular, the batteries of electric or hybrid vehicles provide maximum performance under specific conditions of use and especially in a very specific temperature range. Thus, in cold climates, the autonomy of electric or hybrid vehicles poses a problem, especially since significant heating needs consume a large part of the stored electrical energy. In addition, at low temperatures, the available battery power is low, which poses a driving problem. Moreover, the cost of the battery contributes significantly to the cost of the electric or hybrid vehicle.

Conversely, battery cooling represents a major safety issue. Different dielectric oils can be used to cool the battery of an electric or hybrid vehicle. However, when rapid charging of the battery is required, the use of a single-phase cooling system using for example dielectric oils alone is not sufficient to effectively cool the battery. In this case, a cooling system with phase change of heat composition should be considered. Fluids, such as refrigerants, which are more volatile and less viscous must be used. However, these fluids have vapor pressures higher than those observed in the case of dielectric oils, which may require reinforcement of the battery case (and therefore an increase in its weight) in order to withstand the pressure. These fluids also have a higher cost than dielectric oils. They also have a much higher density than dielectric fluids, which can make the system heavier.

In addition, it is important to use low or non-flammable compositions near the battery in order to eliminate any risk related to the safety of the use of these compositions.

Document FR 2973809 concerns the use of a zeolite adsorbent to improve the thermal stability of an oil subjected to temperature variations in refrigerant fluid compositions.

Document FR 2962442 relates to a stable composition comprising 2,3,3,3-tetrafluoropropene, for use in refrigeration and air conditioning.

Document US 2014/057826 relates to a heat transfer composition comprising at least one hydrochlorofluoroolefin used for air conditioning, refrigeration and heat pump applications or used for cleaning products, components, substrates or other articles containing the substance to be to clean.

WO 2019/242977 relates to fluid-insulated switchgear that includes a fluid compartment filled with an electrically insulating fluid and an electrical conductor placed in the fluid compartment and electrically insulated by the electrically insulating fluid.

Document WO 2019/162598 relates to the use of a refrigerant comprising 2,3,3,3-tetrafluoropropene for maintaining the temperature of a battery of an electric or hybrid vehicle in a temperature range.

Document WO 2019/162599 relates to the use of a refrigerant comprising 2,3,3,3-tetrafluoropropene for preheating a battery of an electric or hybrid vehicle from the start of the vehicle.

Document WO 2019/197783 relates to a method of cooling and/or heating a body or a fluid in a motor vehicle, by means of a system comprising a vapor compression circuit in which circulates a first composition of heat transfer and a secondary circuit in which a second heat transfer composition circulates.

Documents WO 2020/011888, WO 2020/100152, WO 2020/007954, US 9,865,907, US 10,784,545, FR 3037727, FR 3075471, FR 3085542, FR 3085545, FR 3085547, FR 308 5556 and EP 3499634 describe thermal regulation systems of batteries by direct contact with a fluid.

There is a need to ensure optimal operation of batteries, particularly in electric or hybrid vehicles, in order to provide efficient batteries with long and secure lifespans without increasing costs.

The invention firstly relates to the use of a heat transfer composition comprising from 20% to less than 100% by weight of a refrigerant fluid comprising a compound chosen from halogenated hydrocarbons, perhalogenated compounds, fluorinated ketones , fluorinated ethers as well as their combinations, and more than 0% to 80% by weight of a dielectric fluid, for cooling a battery, the battery comprising energy storage cells immersed in the heat transfer composition, and the heat transfer composition undergoing evaporation upon contact with the energy storage cells.

In embodiments, the heat transfer composition flows through a heat transfer circuit.

In embodiments, the battery comprises one or more modules each comprising an enclosure in which energy storage cells are arranged, the enclosure(s) forming part of the heat transfer circuit.

In embodiments, the heat transfer circuit is thermally coupled to a secondary circuit containing an additional transfer composition.

In embodiments, the secondary circuit is the air conditioning circuit of a vehicle; and/or is a reversible heat pump circuit.

In embodiments, the refrigerant comprises or is 1 chloro 3,3,3 trifluoropropene, preferably in the E form, or is a binary, preferably azeotropic mixture of 1 chloro 3,3,3 trifluoropropene in the Z form and 1,1,1,2,3-pentafluoropropane, or 1,1,1,4,4,4-hexafluorobut-2-ene in Z form and 1,2-dichloroethylene in E form.

In embodiments, the dielectric fluid is chosen from mineral dielectric oils, synthetic dielectric oils, and vegetable dielectric oils, and preferably from aromatic hydrocarbons chosen from alkylbenzenes, alkyldiphenylethanes, alkylnaphthalenes, methylpolyarylmethanes as well as their combinations, poly (alpha) olefins and polyol esters.

In embodiments, the battery is the battery of an electric or hybrid vehicle, preferably an electric or hybrid automobile.

In embodiments, the use is implemented when charging the vehicle battery, the vehicle battery preferably being fully charged in a period of less than or equal to 30 min, and preferably less than or equal to 15 min from its total discharge.

The invention also relates to a battery assembly, in particular for an electric or hybrid vehicle, comprising one or more modules each comprising an enclosure in which energy storage cells are arranged immersed in a heat transfer composition, the transfer composition of heat comprising from 20% to less than 100% by weight of a refrigerant comprising a compound chosen from halogenated hydrocarbons, perhalogenated compounds, fluorinated ketones, fluorinated ethers as well as combinations thereof, and from more than 0% to 80% by weight of a dielectric fluid, the battery assembly configured such that the heat transfer composition undergoes evaporation to cool the battery.

In embodiments, the assembly comprises a heat transfer circuit in which the heat transfer composition circulates, the enclosure(s) of the module(s) being integrated into this heat transfer circuit.

In embodiments, the heat transfer circuit includes a pump; and/or the heat transfer circuit includes a heat exchanger to enable heat exchange of the heat transfer composition either with ambient air or with a heat transfer composition in a secondary circuit.

In embodiments, the refrigerant comprises or is 1 chloro 3,3,3 trifluoropropene, preferably in the E form, or is a binary, preferably azeotropic mixture of 1 chloro 3,3,3 trifluoropropene in the Z form and 1,1,1,2,3-pentafluoropropane, or 1,1,1,4,4,4-hexafluorobut-2-ene in Z form and 1,2-dichloroethylene in E form.

In embodiments, the dielectric fluid is chosen from mineral dielectric oils, synthetic dielectric oils, and vegetable dielectric oils, and preferably from alkylbenzenes, alkyldiphenylethanes, alkylnaphthalenes, methylpolyarylmethanes as well as their combinations, poly (alpha)olefins and polyol esters.

The invention also relates to a method of regulating the battery temperature of the battery assembly described above, comprising cooling the energy storage cells by the heat transfer composition by partial evaporation of the composition of heat transfer.

The present invention makes it possible to meet the need expressed above. It makes it possible to ensure optimal operation of the equipment, in particular an electric or hybrid vehicle battery (in particular the vehicle's traction battery), so as to provide high-performance batteries with long and secure lifespans. without increasing costs.

This is accomplished through the use of a heat transfer composition comprising from 20% to less than 100% by weight of a refrigerant chosen from halogenated hydrocarbons, perhalogenated compounds, fluorinated ketones, fluorinated ethers as well as than combinations thereof, and more than 0% to 80% of a dielectric fluid, the energy storage cells of the battery being immersed in the heat transfer composition and the heat transfer composition undergoing evaporation on contact energy storage cells.

Indeed, the combination of a dielectric fluid with a refrigerant makes it possible to maintain heat transfer properties that are far superior to those of a dielectric fluid in the liquid phase.

Compared to the use of a refrigerant alone, the invention makes it possible to reduce cost and weight without significant degradation of battery performance, lifespan, or safety.

In addition, the vapor pressure of the composition is generally lower than that of the refrigerant alone, which makes it possible to reduce the constraints of reinforcing the installation.

Thus, the invention generally makes it possible to increase the efficiency and lifespan of batteries, particularly during rapid charging, without increasing costs.

Preferably, the refrigerant has a boiling point lower than 50°C, more preferably lower than 30°C, and in particular lower than 25°C or 20°C (at 1 bar). A relatively low boiling temperature can help slow the spread in the event of a battery thermal runaway.

Preferably, the composition has a volume resistivity greater than or equal to 10 ⁶ Ω.cm at 25°C. Preferably, the composition has a breakdown voltage greater than or equal to 20 kV at 20°C. This ensures that the dielectric properties of the composition are compatible, from a safety point of view, with use in direct contact with the battery.

The refrigerant makes it possible to reduce the viscosity of the dielectric fluid and possibly make the composition more volatile, and therefore more effective. The refrigerant also makes it possible to reduce the liquid saturation temperature of the composition (compared to a composition comprising only dielectric fluid) and to improve the cooling efficiency of the battery. Compared to a composition comprising only refrigerant, the invention makes it possible to reduce the constraints linked to the pressure resistance of the installation.

Advantageously, the combination of refrigerant with the dielectric fluid also makes it possible to obtain compositions which are slightly or non-flammable.

Brief description of the figures

There is a diagram which illustrates one embodiment of a battery assembly according to the invention.

There is a diagram which illustrates one embodiment of a battery assembly according to the invention.

There is a diagram which illustrates one embodiment of a battery assembly according to the invention.

There is a diagram which illustrates one embodiment of a battery assembly according to the invention.

There is a diagram that illustrates the variation of the liquid saturation temperature of the heat transfer composition at a pressure of 1 bar, as a function of the refrigerant content (see the examples section below). The temperature is represented on the ordinate (°C) and the dielectric fluid content is represented on the abscissa (% by weight).

detailed description

The invention is now described in more detail and in a non-limiting manner in the description which follows.

Heat Transfer Composition

The heat transfer composition according to the invention comprises at least one refrigerant and at least one dielectric fluid.

By “ refrigerant ” is meant a fluid capable of absorbing heat by evaporating at low temperature and low pressure and of rejecting heat by condensing at high temperature and high pressure.

The refrigerant comprises a compound chosen from halogenated hydrocarbons, perhalogenated compounds, fluorinated ketones, fluorinated ethers and combinations thereof.

The refrigerant may consist of one or more such compounds. Alternatively, it may also comprise one or more additional compounds chosen from hydrocarbons (alkanes or olefins, in particular propane, butane, isobutane, pentane, isopentane), CO ₂ and oxygenated hydrocarbons (in particular methoxymethane, ethoxyethane and methyl formate).

Preferably, the refrigerant consists of C1, C2, C3, C4 and/or C5 compounds; preferably still in C1, C2, C3 and/or C4.

Among the halogenated hydrocarbons, mention may be made of hydrofluorocarbons, hydrochlorofluorocarbons, hydrofluoroolefins, hydrochloroolefins and hydrochlorofluoroolefins.

By way of example, the refrigerant can be chosen from 1,1,1,4,4,4-hexafluorobut-2-ene (HFO-1336mzz, E or Z isomer), 1-chloro-3,3 ,3-trifluoropropene (HCFO-1233zd, E or Z isomer), 3,3,4,4,4-pentafluorobut-1-ene (HFO-1345fz), 2,4,4,4-tetrafluorobut-1- ene (HFO-1354mfy), 1,1,2-trifluoroethylene (HFO-1123), 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,3,3,3-tetrafluoropropene (HFO- 1234ze, isomer E or Z, preferably E), 1-chloro-2,3,3,3-tetrafluoropropene (HCFO-1224yd, isomer E or Z, preferably Z), difluoromethane (HFC-32), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,2,2-tetrafluoroethane (HFC-134), 1,1-difluoroethane (HFC-152a), pentafluoroethane (HFC-125) , 1,1,1,3,3-pentafluoropropane (HFC-245fa), 1,1,1,2,3-pentafluoropropane (HFC-245eb), 1,1,1,2,3,3-hexafluoropropane (HFC-236ea), 1,1,1,3,3-pentafluorobutane (HFC-365mfc), fluoroethane (HFC-161), 1,1,1,2,3,3,3-heptafluoropropane (HFC -227ea), 1,1,1-trifluoropropane (HFC-263fb), 1,2-dichloroethylene (HCO-1130, isomer E or Z, preferably E) and combinations thereof.

Preferred compounds include HCFO-1233zd (preferably in E form), HFO-1336mzz (preferably in Z form) and HCFO-1224yd (preferably in Z form).

Perhalogenated compounds are composed of carbon atoms and halogen atoms only. Examples include perfluorinated compounds such as dodecafluoropentane, tetradecafluorohexane, hexadecafluoroheptane and their combinations.

Among the fluorinated ketones, we can cite for example fluorinated mono ketones, perfluorinated monoketones such as 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone and their combinations.

Among the fluorinated ethers, we can cite for example hydrofluoroethers such as methoxynonafluorobutane (HFE7100), ethoxy-nonafluorobutane (HFE-7200), 1-methoxyheptafluoropropane (HFE-7000), perfluoropolyethers and their combinations.

The refrigerant may comprise several, for example two, or three, or four or five compounds as described above.

• un mélange de HFO-1234yf et de HFC-134a ;
• un mélange de HFO-1336mzz(Z) et HCO-1130(E) ;
• un mélange de HFO-1234ze(E) et HFC-227ea ;
• un mélange de HFO-1234yf, HFC-134a et HFC-152a ;
• un mélange de HFC-32, HFC-152a et HFO-1234ze(E) ;
• un mélange de CO₂, HFC-134a et HFO-1234ze(E) ;
• un mélange de HFC-32, HFO-1234ze(E) et butane ;
• un mélange de HFC-32, HFC-125 et HFO-1234ze(E) ;
• un mélange de HFC-32, HFC-125, HFO-1234yf, HFC-134a et HFO-1234ze(E) ;
• un mélange de HFC-32, HFC-125, HFO-1234yf et HFC-134a ;
• un mélange de HFC-134a et HFO-1234ze(E) ;
• un mélange de HFC-32, HFC-125 et HFO-1234yf ;
• un mélange de HFC-32 et HFO-1234yf ;
• un mélange de CO₂, HFC-32 et HFO-1234yf) ;
• un mélange de HFC-32, HFC-134a et HFO-1234ze(E) ;
• un mélange de HFC-32, HFO-1234yf et HFC-152a ;
• un mélange de HFC-32, HFO-1234yf et HFO-1234ze(E) ;
• un mélange de HFC-32, HFC-125, HFC-134a et HFO-1234ze(E) ;
• un mélange de HFC-32, HFC-125, HFC-134a et HFO-1234ze(E) ;
• un mélange de CO₂, HFC-32, HFC-125, HFO-1234yf et HFC-134a ;
• un mélange de HFC-32, HFC-125, HFO-1234ze(E) et HFC-227ea ; et
• un mélange de HFC-32, propane et HFO-1234yf.

For example, the refrigerant may consist (or essentially consist) of:

• a mixture of HFO-1234yf and HFC-134a;
• a mixture of HFO-1336mzz(Z) and HCO-1130(E);
• a mixture of HFO-1234ze(E) and HFC-227ea;
• a mixture of HFO-1234yf, HFC-134a and HFC-152a;
• a mixture of HFC-32, HFC-152a and HFO-1234ze(E);
• a mixture of CO ₂ , HFC-134a and HFO-1234ze(E);
• a mixture of HFC-32, HFO-1234ze(E) and butane;
• a mixture of HFC-32, HFC-125 and HFO-1234ze(E);
• a mixture of HFC-32, HFC-125, HFO-1234yf, HFC-134a and HFO-1234ze(E);
• a mixture of HFC-32, HFC-125, HFO-1234yf and HFC-134a;
• a mixture of HFC-134a and HFO-1234ze(E);
• a mixture of HFC-32, HFC-125 and HFO-1234yf;
• a mixture of HFC-32 and HFO-1234yf;
• a mixture of CO ₂ , HFC-32 and HFO-1234yf);
• a mixture of HFC-32, HFC-134a and HFO-1234ze(E);
• a mixture of HFC-32, HFO-1234yf and HFC-152a;
• a mixture of HFC-32, HFO-1234yf and HFO-1234ze(E);
• a mixture of HFC-32, HFC-125, HFC-134a and HFO-1234ze(E);
• a mixture of HFC-32, HFC-125, HFC-134a and HFO-1234ze(E);
• a mixture of CO ₂ , HFC-32, HFC-125, HFO-1234yf and HFC-134a;
• a mixture of HFC-32, HFC-125, HFO-1234ze(E) and HFC-227ea; And
• a mixture of HFC-32, propane and HFO-1234yf.

Thus, the refrigerant can be a pure substance or a mixture. When it is a mixture, it is preferably an azeotropic, or quasi-azeotropic, mixture.

• R-513A (56 % de HFO-1234yf et 44 % de HFC-134a) ;
• R-513B (58,5 % de HFO-1234yf et 41,5 % de HFC-134a) ;
• R-514A (74,7 % de HFO-1336mzz(Z) et 25,3 % de HCO-1130(E)) ;
• R-515A (88 % de HFO-1234ze(E) et 12 % de HFC-227ea) ;
• R-516A (77,5 % de HFO-1234yf, 8,5 % de HFC-134a et 14 % de HFC-152a).

Preferred azeotropic compositions are the refrigerants:

• R-513A (56% HFO-1234yf and 44% HFC-134a);
• R-513B (58.5% HFO-1234yf and 41.5% HFC-134a);
• R-514A (74.7% HFO-1336mzz(Z) and 25.3% HCO-1130(E));
• R-515A (88% HFO-1234ze(E) and 12% HFC-227ea);
• R-516A (77.5% HFO-1234yf, 8.5% HFC-134a and 14% HFC-152a).

• R-444A (12 % de HFC-32, 5 % de HFC-152a et 83 % de HFO-1234ze(E)) ;
• R-444B (41,5 % de HFC-32, 10 % de HFC-152a et 48,5 % de HFO-1234ze(E)) ;
• R-445A (6 % de CO₂, 9 % de HFC-134a et 85 % de HFO-1234ze(E)) ;
• R-446A (68 % de HFC-32, 29 % de HFO-1234ze(E) et 3 % de butane) ;
• R-447A (68 % de HFC-32, 3,5 % de HFC-125 et 28,5 % de HFO-1234ze(E)) ;
• R-447B (68 % de HFC-32, 8 % de HFC-125 et 24 % de HFO-1234ze(E)) ;
• R-448A (26 % de HFC-32, 26 % de HFC-125, 20 % de HFO-1234yf, 21 % de HFC-134a et 7 % de HFO-1234ze(E)) ;
• R-449A (24,3 % de HFC-32, 24,7 % de HFC-125, 25,3 % de HFO-1234yf et 25,7 % de HFC-134a) ;
• R-449B (25,2 % de HFC-32, 24,3 % de HFC-125, 23,2 % de HFO-1234yf et 27,3 % de HFC-134a) ;
• R-449C (20 % de HFC-32, 20 % de HFC-125, 31 % de HFO-1234yf et 29 % de HFC-134a) ;
• R-450A (42 % de HFC-134a et 58 % de HFO-1234ze(E)) ;
• R-451A (89, 8 % de HFO-1234yf et 10,2 % de HFC-134a) ;
• R-451B (88, 8 % de HFO-1234yf et 11,2 % de HFC-134a) ;
• R-452A (11 % de HFC-32, 59 % de HFC-125 et 30 % de HFO-1234yf) ;
• R-452B (67 % de HFC-32, 7 % de HFC-125 et 26 % de HFO-1234yf) ;
• R-452C (12,5 % de HFC-32, 61 % de HFC-125 et 26,5 % de HFO-1234yf) ;
• R-454A (35 % de HFC-32 et 65 % de HFO-1234yf) ;
• R-454B (68,9 % de HFC-32 et 31,1 % de HFO-1234yf) ;
• R-454C (21,5 % de HFC-32 et 78,5 % de HFO-1234yf) ;
• R-455A (3 % de CO₂, 21,5 % de HFC-32 et 75,5 % de HFO-1234yf) ;
• R-456A (6 % de HFC-32, 45 % de HFC-134a et 49 % de HFO-1234ze(E)) ;
• R-457A (18 % de HFC-32, 70 % de HFO-1234yf et 12 % de HFC-152a) ;
• R-459A (68 % de HFC-32, 26 % de HFO-1234yf et 6 % de HFO-1234ze(E)) ;
• R-459B (21 % de HFC-32, 69 % de HFO-1234yf et 10 % de HFO-1234ze(E)) ;
• R-460A (12 % de HFC-32, 52 % de HFC-125, 14 % de HFC-134a et 22 % de HFO-1234ze(E)) ;
• R-460B (28 % de HFC-32, 25 % de HFC-125, 20 % de HFC-134a et 27 % de HFO-1234ze(E)) ;
• R-460C (2,5 % de HFC-32, 2,5 % de HFC-125, 46 % de HFC-134a et 49 % de HFO-1234ze(E)) ;
• R-460A (12 % de HFC-32, 52 % de HFC-125, 14 % de HFC-134a et 22 % de HFO-1234ze(E)) ;
• R-463A (6 % de CO₂, 36 % de HFC-32, 30 % de HFC-125, 14 % de HFO-1234yf et 14 % de HFC-134a) ;
• R-464A (27 % de HFC-32, 27 % de HFC-125, 40 % de HFO-1234ze(E) et 6 % de HFC-227ea) ; et
• R-465A (21 % de HFC-32, 7,9 % de propane et 71,1 % de HFO-1234yf).

Alternatively, in certain embodiments, zeotropic compositions can be used, and in particular refrigerants:

• R-444A (12% HFC-32, 5% HFC-152a and 83% HFO-1234ze(E));
• R-444B (41.5% HFC-32, 10% HFC-152a and 48.5% HFO-1234ze(E));
• R-445A (6% CO ₂ , 9% HFC-134a and 85% HFO-1234ze(E));
• R-446A (68% HFC-32, 29% HFO-1234ze(E) and 3% butane);
• R-447A (68% HFC-32, 3.5% HFC-125 and 28.5% HFO-1234ze(E));
• R-447B (68% HFC-32, 8% HFC-125 and 24% HFO-1234ze(E));
• R-448A (26% HFC-32, 26% HFC-125, 20% HFO-1234yf, 21% HFC-134a and 7% HFO-1234ze(E));
• R-449A (24.3% HFC-32, 24.7% HFC-125, 25.3% HFO-1234yf and 25.7% HFC-134a);
• R-449B (25.2% HFC-32, 24.3% HFC-125, 23.2% HFO-1234yf and 27.3% HFC-134a);
• R-449C (20% HFC-32, 20% HFC-125, 31% HFO-1234yf and 29% HFC-134a);
• R-450A (42% HFC-134a and 58% HFO-1234ze(E));
• R-451A (89.8% HFO-1234yf and 10.2% HFC-134a);
• R-451B (88.8% HFO-1234yf and 11.2% HFC-134a);
• R-452A (11% HFC-32, 59% HFC-125 and 30% HFO-1234yf);
• R-452B (67% HFC-32, 7% HFC-125 and 26% HFO-1234yf);
• R-452C (12.5% HFC-32, 61% HFC-125 and 26.5% HFO-1234yf);
• R-454A (35% HFC-32 and 65% HFO-1234yf);
• R-454B (68.9% HFC-32 and 31.1% HFO-1234yf);
• R-454C (21.5% HFC-32 and 78.5% HFO-1234yf);
• R-455A (3% CO ₂ , 21.5% HFC-32 and 75.5% HFO-1234yf);
• R-456A (6% HFC-32, 45% HFC-134a and 49% HFO-1234ze(E));
• R-457A (18% HFC-32, 70% HFO-1234yf and 12% HFC-152a);
• R-459A (68% HFC-32, 26% HFO-1234yf and 6% HFO-1234ze(E));
• R-459B (21% HFC-32, 69% HFO-1234yf and 10% HFO-1234ze(E));
• R-460A (12% HFC-32, 52% HFC-125, 14% HFC-134a and 22% HFO-1234ze(E));
• R-460B (28% HFC-32, 25% HFC-125, 20% HFC-134a and 27% HFO-1234ze(E));
• R-460C (2.5% HFC-32, 2.5% HFC-125, 46% HFC-134a and 49% HFO-1234ze(E));
• R-460A (12% HFC-32, 52% HFC-125, 14% HFC-134a and 22% HFO-1234ze(E));
• R-463A (6% CO ₂ , 36% HFC-32, 30% HFC-125, 14% HFO-1234yf and 14% HFC-134a);
• R-464A (27% HFC-32, 27% HFC-125, 40% HFO-1234ze(E) and 6% HFC-227ea); And
• R-465A (21% HFC-32, 7.9% propane and 71.1% HFO-1234yf).

All percentages shown are by weight.

In certain preferred embodiments, the refrigerant comprises HCFO-1233zd in form E or Z, and more preferably in form E.

Preferably, the heat transfer composition according to the invention essentially comprises a single compound, as refrigerant. In this case, it is preferable that this refrigerant is HCFO-1233zd in form E or Z, and even more preferably in form E.

Impurities may be present up to, for example, 1% by weight maximum.

• au moins 99,5 % de HCFO-1233zd(E), de préférence au moins 99,7 %, de préférence encore au moins 99,8 % ;
• une teneur en HFC-245fa inférieure ou égale à 500 ppm, de préférence de 1 à 500 ppm, de préférence encore de 2 à 300 ppm ;
• une teneur en HFO-1234ze (E ou Z) inférieure ou égale à 100 ppm, de préférence de 1 à 100 ppm, de préférence encore de 2 à 50 ppm ;
• une teneur en HCFO-1233zd (Z) inférieure ou égale à 100 ppm, de préférence de 1 à 100 ppm, de préférence encore de 2 à 50 ppm.

The refrigerant may in particular comprise, by weight:

• at least 99.5% HCFO-1233zd(E), preferably at least 99.7%, more preferably at least 99.8%;
• an HFC-245fa content less than or equal to 500 ppm, preferably 1 to 500 ppm, more preferably 2 to 300 ppm;
• an HFO-1234ze content (E or Z) less than or equal to 100 ppm, preferably 1 to 100 ppm, more preferably 2 to 50 ppm;
• a HCFO-1233zd (Z) content less than or equal to 100 ppm, preferably 1 to 100 ppm, more preferably 2 to 50 ppm.

• un mélange consistant (ou consistant essentiellement) en du HCFO-1233zd(E) et du HFC-245eb, de préférence une composition quasi-azéotropique ou azéotropique ;
• un mélange consistant (ou consistant essentiellement) en du HFO-1366mzz(Z) et du HCO-1130(E), de préférence une composition quasi-azéotropique ou azéotropique, et de préférence encore le réfrigérant R-514A.

Other favorite compositions are:

• a mixture consisting (or consisting essentially) of HCFO-1233zd(E) and HFC-245eb, preferably a quasi-azeotropic or azeotropic composition;
• a mixture consisting (or consisting essentially) of HFO-1366mzz(Z) and HCO-1130(E), preferably a quasi-azeotropic or azeotropic composition, and more preferably the refrigerant R-514A.

The refrigerant according to the invention may in particular have a liquid viscosity of 0.1 to 2 cP at 20°C, preferably 0.2 to 0.9 CP at 20°C. Viscosity can be measured using the method shown in Example 2 below.

The refrigerant according to the invention may in particular have a liquid saturation temperature of 0 to 50°C, preferably 10 to 30, in particular 15 to 25°C, at 1 bar.

The refrigerant according to the invention may in particular have a density of 1 to 1.7, preferably 1 to 1.5, preferably 1 to 1.4 at 20°C.

The refrigerant according to the invention may in particular have a liquid saturation pressure less than or equal to 2 bar at 30°C.

By “ dielectric fluid ” is meant, within the meaning of the present invention, a fluid, generally an oil, which does not (or only minimally) conduct electricity but allows electrostatic forces to be exerted.

By “ oil ” we mean a fatty substance which is in the liquid state at room temperature and which is immiscible with water. Oils are fatty liquids, of vegetable, mineral or synthetic origin. It can be chosen from oils belonging to groups I to V as defined in the API classification (or their equivalents according to the ATIEL classification).

Insulating oils (dielectric) have heat transfer fluid characteristics and therefore participate in heat transfer just like the refrigerant.

The oil included in the heat transfer composition may in particular be chosen from mineral dielectric oils, synthetic dielectric oils possibly biosourced, and vegetable dielectric oils as well as their combinations.

Preferably, the dielectric fluid comprises at least one mineral dielectric oil. Non-limiting examples of such mineral dielectric oils include paraffinic oils and naphthenic oils, such as dielectric oils of the Nytro family, marketed by the company Nynas (in particular Nytro Taurus, Nytro Libra, Nytro 4000X and Nytro 10XN), and Dalia, marketed by the Shell company.

The mineral dielectric oils may preferably be paraffinic oils (that is to say linear or branched saturated hydrocarbons) such as Nytro Taurus oil marketed by the Nynas company and Dalia oil marketed by the Shell company, or naphthenics (i.e. cyclic paraffins) such as Nytro libra and Nytro 10XN oils marketed by the company Nynas, aromatic compounds (i.e. cyclic unsaturated hydrocarbons containing one or more rings characterized by double bonds alternating with single bonds) and non-hydrocarbon compounds.

Preferably, the dielectric fluid is a synthetic dielectric oil, possibly biosourced. Preferably, these may be aromatic hydrocarbons, aliphatic hydrocarbons, silicone oils, esters and polyesters, in particular polyol esters, as well as mixtures of two or more of them in all proportions.

Among the aromatic hydrocarbons, mention may be made, without limitation, of alkylbenzenes, alkyldiphenylethanes (for example phenylxyxlyethane (PXE), phenylethylphenylethane (PEPE), mono-isopropylbiphenyl (MIPB), 1,1-diphenylethane (1,1-DPE )), alkylnaphthalenes (e.g. di-iso-propylnaphthalene (DIPN)), methylpolyarylmethanes (e.g. benzyltoluene (BT) and dibenzyltolulene DBT), and mixtures thereof. In said aromatic hydrocarbons, it must be understood that at least one ring is aromatic and that possibly one or more other ring(s) present may be partially or totally unsaturated. We can cite in particular the dielectric fluids marketed by Soltex Inc, by the company Arkema under the name Jarylec ^® , and SAS 60E from the company JX Nippon Chemical Texas Inc.

Among the aliphatic hydrocarbons, mention may be made, in a non-limiting manner, of alkanes, poly (apha) olefins (PAO), for example polyisobutenes (PIB) or vinylidene type olefins, such as those sold for example by the company Soltex. Inc.

The alkanes may in particular comprise at least 8 carbon atoms, for example between 8 and 22 carbon atoms, preferably between 15 and 22 carbon atoms.

The PAOs can be chosen from group IV and are for example obtained from monomers comprising from 4 to 32 carbon atoms, for example from octene or decene. The weight average molecular weight of PAO can vary quite widely. Preferably, the weight average molecular mass of the PAO is less than 600 Da. The weight average molecular mass of the PAO can also range from 100 to 600 Da, from 150 to 600 Da, or even from 200 to 600 Da. For example, PAOs having a kinematic viscosity, measured at 100°C according to the ASTM D445 standard, ranging from 1.5 to 8 mm ² /s are sold commercially by Ineos under the brands Durasyn® 162, Durasyn® 164, Durasyn® 166 and Durasyn® 168.

Among the silicone oils, mention may be made, in a non-limiting manner, of linear silicone oils of the polydimethylsiloxane type, such as for example those marketed by the company Wacker under the name Wacker ^® AK.

Among the synthetic esters, we can cite in a non-limiting manner phthalic type esters such as dioctylphthalate (DOP) or di-isononylphthalate (DINP) (marketed for example by the company BASF).

We can also cite in a non-limiting manner the esters resulting from the reaction between a polyalcohol and an organic acid, in particular an acid chosen from C ₄ to C ₂₂ organic acids, saturated or unsaturated. As non-limiting examples of such organic acids, mention may be made of undecanoic acid, heptanoic acid, octanoic acid, palmitic acid, and mixtures thereof. Among the polyols which can be used for the synthesis of the aforementioned esters, we can cite, by way of non-limiting examples, pentaerythritol for the synthesis of MIVOLT DF7 Midel 7131 oil, and Mivolt DFK from the company M&I Materials.

The esters can for example be diesters of formula R ^a -C(O)-O-([C(R) ₂ ] _n -O) _s -C(O)-R ^b , in which each R independently represents an atom hydrogen or a C1-C5 alkyl group, linear or branched, in particular a methyl, ethyl or propyl group, in particular methyl; s is 1, 2, 3, 4, 5 or 6; n is 1, 2 or 3; it being understood that, when s is different from 1, the n can be identical or different; and R ^a and R ^b , identical or different, represent independently of each other, hydrocarbon groups, saturated or unsaturated, linear or branched, having a linear sequence of 6 to 18 carbon atoms. Preferably, when s and n are identical and equal to 2, at least one of the groups R represents a linear or branched C1-C5 alkyl group; and when s is 1 and n is 3, at least one of the R groups linked to the carbon in the beta position of the oxygen atoms of the ester functions represents a hydrogen atom.

Synthetic esters resulting from the reaction between a polyalcohol and an organic acid are, for example, Midel 7131 from the company M&I Materials or the esters from the Nycodiel range from the company Nyco.

Among natural esters and vegetable oils, we can cite, without limitation, products derived from oily seeds or other sources of natural origin. We can cite by way of example and in a non-limiting manner the FR3™ or the Envirotemp™ marketed by the company Cargill or the Midel eN 1215 marketed by the company M&I Materials.

It is also possible to use a polyalkylene glycol (PAG), in particular obtained by polymerization or copolymerization of alkylene oxides comprising from 2 to 8 carbon atoms, in particular from 2 to 4 carbon atoms.

The heat transfer composition according to the invention may comprise one oil or more, for example two, or three, or four or five oils.

A preferred dielectric fluid is a polyol ester made from pentaerythritol.

Another preferred dielectric fluid is a poly (apha) olefin (PAO) comprising mainly (i.e. more than 50% by weight) isoparaffins comprising from 4 to 32 carbon atoms. This fluid belongs to group IV of the API classification.

Preferably, the heat transfer composition according to the invention comprises a single dielectric fluid.

The dielectric fluid may in particular have a viscosity of 1 to 60 cP at 20°C according to the ISO3104 standard.

The dielectric fluid may in particular have a boiling temperature greater than 30°C, as measured by ebulliometry.

The dielectric fluid may be present in the composition at a content of more than 0% to 80%, preferably more than 0 to 65%, more preferably 10 to 45% by weight relative to the total weight of the transfer composition. heat.

For example, this content can be more than 0 to 5%; or 5 to 10%; or 10 to 15%; or 15 to 20%; or 20 to 25%; or 25 to 30%; or 30 to 35%; or 35 to 40%; or 40 to 45%; or 45 to 50%; or 50 to 55%; or 55 to 60%; or 60 to 65%; or 65 to 70%; or 70 to 75%; or 75 to 80%, by weight relative to the total weight of the heat transfer composition.

The refrigerant may be present in the composition at a content of 20 to less than 100%, preferably 35 to less than 100%, more preferably 55 to 90% by weight relative to the total weight of the transfer composition. heat.

For example, this content can be 20 to 25%; or 25 to 30%; or 30 to 35%; or 35 to 40%; 40 to 45%; or 45 to 50%; or 50 to 55%; or 55 to 60%; or 60 to 65%; or 65 to 70%; or 70 to 75%; or 75 to 80%; or 80 to 85%; or 85 to 90%; or 90 to 95%; or from 95 to less than 100%, by weight based on the total weight of the heat transfer composition.

In certain embodiments, the heat transfer composition according to the invention comprises a polyol ester made from pentaerythritol and at least one fluorinated or fluorochlorinated hydrocarbon, such as for example, without limitation, a hydrofluoropropane, a hydrofluoropropene, a hydrochlorofluoropropane, a hydrochlorofluoropropene, as well as their mixtures in all proportions.

In other embodiments, the heat transfer composition according to the invention comprises a poly (alpha) olefin (PAO) and at least one fluorinated or fluorochlorinated hydrocarbon, such as for example, without limitation, a hydrofluoropropane, a hydrofluoropropene, a hydrochlorofluoropropane, a hydrochlorofluoropropene, as well as their mixtures in all proportions.

Preferably, the heat transfer composition according to the invention comprises HCFO-1233zd (preferably in form E) and a polyol ester made from pentaerythritol. Even more preferably, the heat transfer composition according to the invention consists essentially, or even consists, of HCFO-1233zd (preferably in form E) and a polyol ester made from pentaerythritol.

Preferably, the heat transfer composition according to the invention comprises HCFO-1233zd (preferably in E form) and a poly (apha) olefin (PAO). Even more preferably, the heat transfer composition according to the invention consists essentially, or even consists, of HCFO-1233zd (preferably in form E) and a poly (alpha) olefin (PAO). It may also consist primarily, or consist, of HCFO-1233zd in Z form, HFC-245eb and PAO. It may also consist essentially, or consist, of HFO-1336mzz in Z form and a PAO. It may also consist essentially, or consist, of HFO-1336mzz in Z form, HCO-1130 in E form and a PAO.

The composition usable in the context of the present invention may further comprise one or more additives and/or fillers, for example chosen from, without limitation, antioxidants, passivators, pour point depressants, inhibitors of decomposition, perfumes and flavorings, colorings, preservatives, and their mixtures. The presence of a decomposition inhibitor is particularly preferred.

Among the antioxidants which can be advantageously used in the composition, mention may be made, by way of non-limiting examples, of phenolic antioxidants, such as for example dibutylhydroxytoluene, butylhydroxyanisole, tocopherols, as well as the acetates of these antioxidants. phenolics; amine type antioxidants, such as for example phenyl-α-naphthylamine, of the diamine type, for example N,N'-di-(2-naphthyl)-para-phenylenediamine, ascorbic acid and its salts, ascorbic acid esters, alone or in mixtures of two or more of them or with other components, such as for example green tea extracts, coffee extracts.

A particularly suitable antioxidant is that available commercially from the company Brenntag under the trade name ^Ionol® .

The passivators which can be used in the context of the present invention are advantageously chosen from triazole derivatives, benzimidazoles, imidazoles, thiazole and benzothiazole. By way of example and in a non-limiting manner, dioctylaminomethyl-2,3-benzotriazole and 2-dodecyldithioimidazole may be mentioned.

Among the pour point depressants which may be present, mention may be made, by way of non-limiting examples, of sucrose fatty acid esters, acrylic polymers such as poly(alkyl methacrylate) or even poly(alkyl acrylate).

The preferred acrylic polymers are those whose molecular weight is between 50,000 g.mol ^-1 and 500,000 g.mol ^-1 . Examples of these acrylic polymers include polymers which may contain linear alkyl groups comprising from 1 to 20 carbon atoms.

Among these, and still by way of non-limiting examples, mention may be made of poly(methyl acrylate), poly(methyl methacrylate), poly(heptyl acrylate), poly(heptyl methacrylate ), poly(nonyl acrylate), poly(nonyl methacrylate), poly(undecyl acrylate), poly(undecyl methacrylate), poly(tridecyl acrylate), poly(tridecyl methacrylate), poly(pentadecyl acrylate), poly(pentadecyl methacrylate), poly(heptadecyl acrylate), and poly(heptadecyl methacrylate).

An example of such a pour point depressant is commercially available from Sanyo Chemical Industries, Ltd, under the trade name Aclube.

In a particularly preferred aspect, a decomposition inhibitor is present as an additive. The decomposition inhibitor may in particular be chosen from carbodiimide derivatives such as diphenyl carbodiimide, di-tolylcarbodiimide, bis(isopropylphenyl)carbodiimide, bis(butylphenyl)carbodiimide; but also among phenylglycidyl ethers, or esters, alkylglycidyl ethers, or esters, 3,4-epoxycyclohexylmethyl-(3,4-epoxycyclohexane) carboxylate, compounds of the anthraquinone family, such as for example β-methylanthraquinone marketed under the name “ BMAQ ”, epoxidized derivatives such as vinylcyclohexene diepoxides, 3,4-epoxy-6-methylcyclohexylmethyl-(3,4-epoxy-6-methylhexane) carboxylate, phenol novolak type epoxy resins, diglycidyl ether epoxy of bisphenol A, such as DGEBA or CEL 2021P, available in particular from the company Whyte Chemicals.

The total quantity of additives preferably does not exceed 5% by weight, in particular 4%, more particularly 3% and very particularly 2% by weight or even 1% by weight of the heat transfer composition.

The composition according to the invention can be prepared by any means well known to those skilled in the art, for example by simply mixing the various components of the composition according to the invention.

In some embodiments, the heat transfer composition contains impurities. When present, they may represent less than 1%, preferably less than 0.5%, preferably less than 0.1%, preferably less than 0.05% and preferably less than 0.01% ( by weight) relative to the heat transfer composition.

The choice of the different components is not limiting as long as the heat transfer composition according to the invention has the properties (thermal conductivity, viscosity, resistivity, breakdown voltage, etc.) required for the intended application. Preferably a volume resistivity greater than or equal to 10 ⁶ Ω.cm at 25°C, and preferably greater than or equal to 10 ⁷ Ω.cm or 10 ⁸ Ω.cm. The resistivity of a material represents its ability to oppose the flow of electric current. In other words, volume resistivity is an indication of the dielectric properties of the composition. Volume resistivity is measured according to the IEC 60247 standard.

For example, this volume resistivity can be from 10 ⁶ to 5x10 ⁶ Ω.cm; or from 5x10 ⁶ to 10 ⁷ Ω.cm; or from 10 ⁷ to 5x10 ⁷ Ω.cm; or from 5x10 ⁷ to 10 ⁸ Ω.cm; or from 10 ⁸ to 5x10 ⁸ Ω.cm; or from 5x10 ⁸ to 10 ⁹ Ω.cm; or more than 10 ⁹ Ω.cm.

In addition, the heat transfer composition according to the invention preferably has a breakdown voltage at 20°C greater than or equal to 20 kV, preferably greater than or equal to 20 kV, preferably greater than or equal to 30 kV, of preferably greater than or equal to 50 kV, and more preferably greater than or equal to 100 kV. By “ breakdown voltage ” we mean the minimum electrical voltage which makes a portion of an insulator conductive. Thus, this parameter is also an indication of the dielectric properties of the composition. The breakdown voltage is measured according to the IEC 60156 standard.

For example, the breakdown voltage at 20°C of the composition according to the invention can be 25 to 30 kV; or 30 to 40 kV; or 40 to 50 kV; or 50 to 60 kV; or 60 to 70 kV; or 70 to 80 kV; or 80 to 90 kV; or 90 to 100 kV; or 100 to 110 kV; or 110 to 120 kV; or 120 to 130 kV; or 130 to 140 kV; or 140 to 150 kV.

The heat transfer composition according to the invention can also have a liquid saturation temperature of 20 to 80°C, and preferably of 30 to 70°C at a pressure of 1 bar. For example, this temperature can be 20 to 25°C; or 25 to 30°C; or 30 to 35°C; or 35 to 40°C; or 40 to 45°C; or 45 to 50°C; or from 50 to 55°C; or from 55 to 60°C; or from 60 to 65°C; or from 65 to 70°C; or 70 to 75°C; or 75 to 80°C.

The heat transfer composition according to the invention may in particular have a viscosity of 0.1 to 20 cP at 20°C according to the ISO 3104 standard.

The heat transfer composition according to the invention is preferably not very flammable (that is to say having a high flash point, for example greater than 150°C, or 200°C, or 250°C, or at 300°C, according to standards ISO 3679 and ISO 3680) or preferably non-flammable.

Use of heat transfer composition

By referring to the , the battery 402 can power at least one motor 404, in particular a vehicle engine. The vehicle is preferably an automobile, or possibly a construction machine, a scooter, a motorcycle, a truck, a ship, an aircraft, etc.

The battery may include a set of energy storage cells (or accumulators), which may be grouped into a single or several modules. Each module can contain a plurality of cells arranged in a hermetic enclosure. Each module enclosure can be configured to hold cells in a fixed manner.

The battery may include identical or different modules. The modules can be assembled together mechanically and/or connected electrically to form the battery. The modules can be electrically connected in series, or in parallel.

Each enclosure can for example comprise an upper portion and a lower portion connected together, for example by welding, gluing or screwing.

The cells can for example be cylindrical in shape. Each module can comprise from 2 to 200 cells, preferably from 4 to 100 cells, more preferably from 6 to 50 cells. The cells can for example be arranged in N rows of M cells in each module. N can be worth for example from 1 to 10, for example can be worth 2. M can be worth for example from 1 to 60, and for example can be a multiple of 3 (namely 3, 6, 12, 18, 30…). In certain embodiments, the cells can be arranged in a three-dimensional arrangement in each module, with a stack of P layers of NxM cells. The number of layers P can then be for example from 2 to 5. Alternatively, only one layer is present.

The cells can be, for example, nickel-cadmium (NiCd), nickel metal hydride (Ni-M-H) or lithium-ion (Li-ion) rechargeable cells.

Each enclosure can for example be made of plastic material, in particular polystyrene, polyvinyl chloride, polycarbonate, polyethylene, polypropylene, acrylic polymer and in particular polymethyl methacrylate, phenolic resin, etc. Alternatively, it can be made of metallic material, for example aluminum .

The heat transfer composition is used to cool a battery. This cooling is accomplished by placing the heat transfer composition in direct contact with energy storage cells of the battery, with the heat transfer composition at least partially changing state (undergoing evaporation) upon contact with the cells. That is, the energy storage cells are immersed in the heat transfer composition.

By “ immersed ” we mean that the cells are in contact with the heat transfer composition. More particularly, the exterior surfaces of the cells are in contact with the heat transfer composition. Preferably, they are in contact with the heat transfer composition essentially in liquid form.

The cells can thus be placed in a bath of heat transfer composition. The heat transfer composition can occupy the entire internal space of the module, between the cells and the wall of the enclosure, or preferably a gaseous sky can be provided. Preferably, the entire surface of the cells in the enclosure is in contact with the composition in liquid form.

Alternatively, the surface of the cells can be covered with a liquid film obtained using suitable means (watering, projection, jet, etc.) and/or by specific treatment of the surface of the cells.

For example, the heat transfer composition may be sprayed onto the cells by monodirectional or multidirectional nozzles. They can for example be arranged between the cells so as to project the heat transfer composition onto the side faces of the cells. Alternatively, they are placed above the cells to project the heat transfer composition onto the upper faces of the cells. The composition can be projected in the form of a jet, or streamed, or in the form of a mist. The composition can be recovered in a tank and recirculated using a pump. A heat exchanger and/or a heating means (for example resistance) can be placed in the tank, or upstream or downstream of the pump, to allow heat to be supplied or removed from the composition. In this variant, bringing the liquid composition into contact with the surface of the cells can be carried out only when there is a need to regulate the temperature of the battery. The rest of the time, and in particular when the battery is not in operation, the surface of the cells may not be in contact with the heat transfer composition.

Optionally, the surface of the cells can be coated with a hydrophilic film to enable a layer of heat transfer composition liquid to be distributed onto the surface of the cells. For example, a nanostructured SiO ₂ film can be used. Alternatively, a filamentary or fibrous structure (comprising one or more wicks, or a woven or non-woven textile), or even an agglomerated metal powder, can be placed on the surface of the cells, to enable a layer of composition liquid to be distributed. heat transfer to the surface of cells by capillarity.

The heat transfer composition is totally or partially vaporized in contact with the cells (in order to cool them).

Preferably, the change of state is partial: the dielectric fluid remains essentially in the liquid state, while the refrigerant undergoes a total or partial change of state.

This makes it possible to take full advantage of the thermal properties of the heat transfer composition. Indeed, cooling by direct contact of the battery cells with the heat transfer composition is useful in the event of rapid charging of the battery, which involves rapid heating of the latter. It allows the temperature to be maintained evenly within its optimal operating range.

The heat transfer composition is contained in a device, adapted to enable heat exchange of the composition with the battery cells, and preferably also with a secondary source.

This device, with the battery itself, constitutes a battery assembly according to the invention.

The secondary source may be ambient air, or an additional heat transfer composition. When dealing with ambient air, a fan or fans can be used to increase the heat exchange with it.

The heat transfer composition may be static or circulating.

If it is static, the device includes the enclosure(s) containing battery cells, as well as the heat transfer composition in contact with these cells. The heat transfer composition exchanges heat with the environment or an additional heat transfer composition via the enclosure itself. The internal wall and/or the external wall of the enclosure may thus include heat dissipation elements such as fins or another raised structure to facilitate heat exchange with the environment or the additional heat transfer composition. Preferably, the heat transfer composition can exchange heat with the additional heat transfer composition, via a heat exchanger located in the enclosure, or directly via the wall of the enclosure, or via plates or channels on the wall of the enclosure.

For example, a condenser can be provided in an upper wall of the enclosure. Thus, the heat transfer composition which undergoes evaporation while cooling the cells can be condensed in this condenser, returning to liquid form. This condenser allows heat exchange with ambient air or with an additional heat transfer composition. The condenser may include channels provided in the upper wall of the enclosure. Ridges, spikes, or other reliefs can help the condensed heat transfer composition flow toward the bottom of the enclosure.

The pressure in the enclosure may vary depending on the temperature in the enclosure. The pressure in the enclosure may, for example, remain less than 5 bar, or less than 4 bar, or less than 2 bar.

When the heat transfer composition is circulating, the device includes a main heat transfer circuit, as illustrated in the .

The flow rate of the heat transfer composition in the main circuit can be from 0 to 100 L/min, preferably from 5 to 50 L/min.

The enclosure of each module may be provided with at least one fluid inlet and at least one fluid outlet, to allow the heat transfer composition to pass through the enclosure, the cells being immersed, preferably entirely, in the heat transfer composition.

To avoid thermal shock, it may be preferred that the temperature of the heat transfer composition, at the entrance to the enclosure, be greater than or equal to 10°C, for example between approximately 20 and approximately 30°C.

To ensure better homogeneity of the thermal regulation of the battery, it may be preferred that temperature shift (difference between the temperature of the heat transfer composition leaving the enclosure and the temperature of the heat transfer composition in entrance to the enclosure) or, in absolute value, less than or equal to 10°C, preferably 5°C, more preferably 2°C, more preferably 1°C.

The modules can be fluidly connected in series, or in parallel, with respect to the circulation of the heat transfer composition.

Referring again to the , the main heat transfer circuit can be configured to transport the heat transfer composition from at least one heat exchanger 408, 408' to the battery 402, and again from the battery 402 to the at least a heat exchanger 408, 408'. The module speaker(s) are integrated into this main circuit. Circulation in the main circuit can be done by convection. The main circuit may also include one or more pipes for supplying the heat transfer composition to the battery and for collecting it; and possibly to transport it between battery modules. Alternatively, the enclosures of the modules can be in direct contact so as to allow the assembly of the respective fluid inlets and outlets of the modules. In this case, joints can be provided between the assembled inlets and outlets.

Distributors and collectors can be attached to or integrated into the enclosures, when several fluid inlets and/or outlets are provided in each enclosure. In some embodiments, distributor and collector portions may be formed within the enclosures themselves, so as to enable collection and distribution of the heat transfer composition from one module to another when the respective enclosures are assembled.

When the heat transfer composition is used to cool the battery, it is completely or preferably partially vaporized as it passes through the enclosure(s).

Preferably, the change of state is carried out between a completely liquid composition and a two-phase liquid - vapor composition when passing through the battery, then again towards a completely liquid composition (within the heat exchanger 408, 408' ) before returning to the battery.

The transport of the heat transfer composition in the main circuit can be ensured by one or more pumps 406. Preferably, the main circuit does not include a compressor: in other words, the heat transfer circuit is not a circuit vapor compression.

The heat exchanger 408 may in particular be a radiator ensuring heat exchange with the ambient air.

Alternatively, the heat exchanger 408' couples the main circuit with a secondary circuit in which an additional heat transfer composition circulates, which itself exchanges heat with another source, for example with the ambient air.

The additional heat transfer composition may be the same as or different from the heat transfer composition. For example, it may be a refrigerant as described above, not mixed with a dielectric fluid. For example, the composition may comprise HFO-1234yf, associated where appropriate with one or more lubricants and other additives. Alternatively, it can be a mixture of water and glycol for example.

This secondary circuit can be a refrigeration circuit, comprising a compressor, an expander, an evaporator and a condenser; or it can be a simple heat transfer circuit without a compressor.

An expansion valve (for example an electronic expansion valve) can be provided upstream of the heat exchanger 408' in this secondary circuit.

A pump can be provided in this secondary circuit to circulate the additional heat transfer composition.

The additional heat transfer composition can optionally change state, in whole or in part, when passing through the heat exchanger 408'. Thus, if the heat transfer composition is cooled in the heat exchanger 408', the additional heat transfer composition is correspondingly heated and can evaporate in whole or in part (for example from a completely liquid state to a biphasic liquid – vapor state). Conversely, if the heat transfer composition is reheated in the heat exchanger 408', the additional heat transfer composition is correspondingly cooled and may condense in whole or in part (e.g. from a two-phase liquid-vapor state). to a completely liquid state).

Optionally, the secondary circuit can be reversible (i.e. it can cool or heat the heat transfer composition which is in contact with the battery, depending on the operating mode).

The heat exchanger 408' allowing heat exchange with the additional heat transfer composition can for example be co-current or, preferably, counter-current.

By “ counter-current heat exchanger ” is meant a heat exchanger in which heat is exchanged between a first fluid and a second fluid, the first fluid at the inlet of the exchanger exchanging heat with the second fluid at the outlet of the exchanger, and the first fluid at the outlet of the exchanger exchanging heat with the second fluid at the inlet of the exchanger.

For example, counter-current heat exchangers include devices in which the flow of the first fluid and the flow of the second fluid are in opposite, or nearly opposite, directions. Exchangers operating in cross-current mode with counter-current tendency are also included among counter-current heat exchangers.

The heat exchangers may in particular be U-tube, horizontal or vertical tube bundle, spiral, plate or fin exchangers.

The additional heat transfer composition itself can exchange heat with the environment, by means of an additional heat exchanger. It can optionally also be used to heat or cool the air in the vehicle cabin. Thus, the heat dissipated by the battery can be absorbed by the vehicle's air conditioning circuit.

For this purpose, the secondary circuit may include different branches equipped with separate heat exchangers, the additional heat transfer composition circulating or not in these branches, depending on the operating mode. Optionally, alternatively or in addition, the secondary circuit may include means for changing the direction of circulation of the additional heat transfer composition, comprising for example one or more three-way or four-way valves.

The main circuit may include a reservoir for storing excess heat transfer composition in liquid form.

The secondary circuit may include a reservoir for storing the additional heat transfer composition in excess liquid form.

When the main circuit is equipped with a pump, protection can be provided, for example upstream of the pump, to ensure that only liquid is pumped to the battery. Indeed, depending on external conditions (for example when the vehicle is hot when starting due to weather conditions), the heat transfer composition can be biphasic upstream of the pump, particularly at the outlet of the tank. The protection may include a bypass system, in particular between the tank and the pump, with a valve, a pressure sensor and a temperature sensor. A filter and a desiccator can be provided to capture impurities and moisture respectively.

It is possible to provide yet a third circuit containing another additional heat transfer composition, thermally connected to the secondary circuit, by a heat exchanger. This third circuit can in particular be dedicated to the recovery of the heat dissipated by the engine and/or the electrical components of the vehicle.

It is possible to provide two or more main circuits operated in parallel and controlled independently, to regulate the temperature of different battery modules, or to control different batteries when there are several.

A battery management system 410 can be associated with the battery 402, in order to measure the electrical parameters (in particular the voltage) but also the temperature of each module (by means of temperature sensors), and control the modules as well as the main circuit (and possibly the secondary circuit), and in particular their pumps, in order to ensure that the electrical parameters in question and the temperature are within the desired ranges.

Particular examples of thermal regulation systems comprising a main circuit and a secondary circuit are now described in more detail.

By referring to the , an example of a battery assembly according to the invention (usable in particular in a vehicle) comprises a thermal regulation system 1 which comprises a main circuit 2 containing the heat transfer composition described above and a secondary circuit 3 containing a additional heat transfer composition, the two circuits being thermally connected by at least one heat exchanger 4. The heat transfer composition in the main circuit 2 is set in motion by a pump 7 or by natural convection. The additional heat transfer composition in the secondary circuit 3 is set in motion by a pump 8. The secondary circuit 3 includes an expansion valve 9 making it possible to ensure the evaporation of the additional heat transfer composition in the exchanger of heat 4, to cool the heat transfer composition of the main circuit 2.

At least one battery module 10 (as described above) is fluidly integrated into the main circuit 2. A heating element 11 may be associated with or integrated into the battery module 10.

When the circuit is equipped with a pump, a reservoir 21 can optionally be provided in the main circuit 2 to receive excess heat transfer composition in liquid form.

In battery cooling mode, the pump 7 takes the heat transfer composition from the tank 21 and sends it to the battery module 10. The heat transfer composition is in the liquid state at the inlet of the battery module. battery 10. It reaches its saturation temperature and is partially vaporized by passing through the battery module 10 and absorbing the heat dissipated by the cells. It leaves the battery module 10 in a liquid-vapor biphasic state. The battery module 10 thus plays the role of evaporator with respect to the main circuit.

The two-phase heat transfer composition then passes through the heat exchanger 4. The additional heat transfer composition is expanded in the expansion valve 9 then totally or partially vaporizes in the heat exchanger 4. The transfer composition heat condenses by transferring heat to the additional heat transfer composition. The heat transfer composition in liquid form then returns to tank 21.

Secondary circuit 3 may be the vehicle's automobile air conditioning circuit (the compressor not being illustrated in the figure).

Referring to Figures 3 and 4 , an example of a battery assembly according to the invention (usable in particular in a vehicle) comprises a thermal regulation system 1 which comprises a main circuit 2 as previously described and a secondary circuit 3 capable of operate as a reversible heat pump. Thus, the battery module 10 can be cooled and heated by the heat transfer composition. The secondary circuit has two operating modes: a cooling mode and a heating mode. Cooling mode is shown on the and the heating mode is shown on the .

Secondary circuit 3 includes an HVAC 16 module (heating, ventilation and air conditioning) ensuring thermal regulation of the air in the passenger compartment. It includes a condenser 17 and an evaporator 18. The condenser 17 is used to heat the air in the passenger compartment and the evaporator 18 is used to cool it.

The secondary circuit 3 further comprises a control valve 19, a stop valve 24, a tank 37 and an external heat exchanger 20. An expansion valve 9 is arranged downstream of the external heat exchanger 20 and a calibrated orifice 25 with stop function is arranged upstream of the evaporator 18. The expansion valve 9, the stop valve 24 and the calibrated orifice 25 can be controlled electrically. The control valve 19 may be a reversible valve and/or a four-way valve capable of changing the direction of flow of the additional heat transfer composition.

In cooling mode, the control valve 19 is in a first position such that the external heat exchanger 20 is used as a condenser while the heat exchanger 4 and the evaporator 18 are used as evaporators. Shutoff valve 24 and calibrated orifice 25 are open in this mode. The additional heat transfer composition in the tank 37 is in a two-phase state and the pump 8 directs it to the external heat exchanger 20. The additional heat transfer composition condenses therein and is directed to the external heat exchanger 20. heat exchanger 4 and the evaporator 18. In both cases, it is at least partially vaporized and returned to the tank 37.

In heating mode, the control valve 19 is in a second position such that the external heat exchanger 20 is used as an evaporator while the heat exchanger 4 and the condenser 17 are used as condensers. Shutoff valve 24 and calibrated orifice 25 are closed in this mode. The additional heat transfer composition in tank 37 is in a two-phase state and pump 8 directs it to condenser 17 where it is partially condensed. Then it goes to heat exchanger 4 where it continues to condense. Then it passes into the external heat exchanger 20 having an evaporator function.

Optionally, a third circuit 12 can be provided and intervene in heating mode. The third circuit 12 can make it possible to recover heat dissipated by a motor 26 and/or electrical components 22 of the vehicle. It may include a pump and a radiator 28. A bypass provided with a stop valve 29 can allow the radiator 28 to be bypassed. The third circuit 12 is thermally connected to the secondary circuit 3 by a second heat exchanger 13. The third circuit can for example include a fluid of the water and glycol mixture type. In heating mode, the additional heat transfer composition, at the outlet of the heat exchanger 4, is distributed in the external heat exchanger 20 and in the second heat exchanger 13, both having an evaporator function. It therefore absorbs the heat dissipated by the fluid of the third circuit 12.

The secondary circuit 3 may comprise two non-return valves 23 on the branch of the circuit comprising the second heat exchanger 13 (in parallel with the branch comprising the external heat exchanger 20), as well as an expansion valve 9 upstream of the second heat exchanger 13.

Temperature regulation

The invention relates to the use of a heat transfer composition according to the invention to cool the battery. However, the composition can also be used, at other times, to heat the battery and remains mainly in liquid form. Heating and cooling can be alternated as needed (outside temperature, battery temperature, battery operating mode). Heating the battery is particularly useful when starting the vehicle, when the outside temperature is cold (for example below 10°C, or 0°C, or -10°C, or -20°C).

The heating can also be carried out at least in part, or even entirely, by means of an auxiliary heating element, for example an electrical resistance. The auxiliary heating element can be mounted on the battery.

It is thus possible to dedicate the heat transfer composition according to the invention solely to cooling the battery in a uniform manner, while other means, for example an electrical resistance, are used for its heating.

Alternatively, a heating element associated with the main circuit can be provided, particularly upstream of the battery. In this case, the heating element is likely to heat the heat transfer composition, which then heats the battery.

By “ battery temperature ” we generally mean the temperature of an exterior wall of one or more of its electrochemical cells.

The battery temperature can be measured using a temperature sensor. If several temperature sensors are present on the battery, the battery temperature can be considered as the average of the different temperatures measured. The invention makes it possible to considerably reduce the difference between the temperatures measured at different points of the battery.

Temperature regulation can be done while the vehicle battery is charging. Alternatively, it can be carried out when the battery is discharging, in particular when the vehicle engine is on. It makes it possible in particular to prevent the temperature of the battery from becoming excessive, due to the external temperature and/or due to the inherent heating of this battery in operation.

In particular, battery charging can be fast charging. Thus, during complete charging of the battery (from a moment when the battery is completely discharged) for a period of less than or equal to 30 min, and preferably less than or equal to 15 min, the use of the composition according to the invention makes it possible to maintain the battery temperature in an optimal temperature range with uniform distribution. This has an advantage given that during rapid charging, the battery tends to heat up quickly and reach high temperatures, including hot spots which can degrade its operation, its performance and shorten its lifespan.

In some embodiments, the cooling of the battery is continuous over a certain period of time.

In certain embodiments, the cooling and optionally the heating make it possible to maintain the temperature of the battery in an optimal temperature range, in particular when the vehicle is in operation (engine on), and in particular when the vehicle is moving. Indeed, if the battery temperature is too low, its performance is likely to decrease significantly.

In certain embodiments, the temperature of the vehicle battery can thus be maintained between a minimum temperature t ₁ and a maximum temperature t ₂ .

In certain embodiments, the minimum temperature t ₁ is greater than or equal to 10°C and the maximum temperature t ₂ is less than or equal to 80°C, preferably the minimum temperature t ₁ is greater than or equal to 15°C and the maximum temperature t ₂ is less than or equal to 70°C, and more preferably the minimum temperature t ₁ is greater than or equal to 16°C and the maximum temperature t ₂ is less than or equal to 50°C. For example, t ₁ can be equal to 20°C (or even greater than 20°C) and t ₂ can be equal to 40°C (or even less than 40°C).

A feedback loop is advantageously present, to modify the operating parameters of the installation according to the temperature of the battery which is measured, in order to ensure that the desired temperature is maintained.

The exterior temperature during the duration of maintaining the temperature of the vehicle battery between the minimum temperature t ₁ and the maximum temperature t ₂ may in particular be from -60 to -50°C; or from -50 to -40°C; or from -40 to -30°C; or from -30 to -20°C; or from -20 to -10°C; or from -10 to 0°C; or from 0 to 10°C; or from 10 to 20°C; or 20 to 30°C; or 30 to 40°C; or 40 to 50°C; or 50 to 60°C; or 60 to 70°C.

By “ external temperature ” we mean the ambient temperature outside the vehicle before and during the maintenance of the temperature of the vehicle battery between the minimum temperature t ₁ and the maximum temperature t ₂ .

Examples

Example 1 – miscibility and dielectric properties

Compositions were prepared by combining HCFO-1233zdE as a refrigerant with a mixture of benzyltoluene and dibenzyltoluene (marketed by Arkema under the name Jarylec ^® C101). It was previously verified that the two products were miscible in all proportions.

The oil was loaded by weighing into a 0.2 L autoclave equipped with a magnetic stirrer and a double jacket in which a heat transfer fluid circulates so as to homogenize the temperature in the gas phase and the liquid phase.

The autoclave was then cooled to -10°C where the vacuum was drawn.

The HCFO-1233zdE contained in a cylinder was transferred in a closed circuit in the liquid phase by weighing.

The minimum volume of loaded liquid was calculated so that the composition of the liquid phase does not vary as a function of temperature.

The final mixture was brought to the desired temperature while stirring in order to homogenize it. Agitation was then stopped until the mixture reached equilibrium. The temperature and pressure were recorded at equilibrium.

There illustrates the influence of the refrigerant content on the liquid saturation temperature of the composition at a saturated vapor pressure of 1 bar. More particularly, we note that compared to a composition comprising 100% oil, the addition of refrigerant in the composition, even in a low content, makes it possible to significantly reduce the liquid saturation temperature of the composition, which allows to increase the cooling capacity of the battery.

A composition was prepared by mixing 69.2 g of HCFO-1233zd E and 100.5 g of Jarylec ^® C101 from the company Arkema, under the conditions presented above.

Autoclave T (°C) Pressure (bar abs) Comments 20 0.71 miscible 60 2.5 miscible

Another composition was prepared by mixing 35% by weight of HCFO-1233zdE and 65% by weight of Jarylec ^® C101, from the company Arkema, under the conditions presented below.

The breakdown voltage was measured according to the IEC 60159:1995 standard.

Jarylec ^® C101
(% weight) R1233zd E
(% weight) Resistivity at 10°C Breakdown voltage at 20°C
(kV) 100 0 3.12 x 10 ¹³ 90 65 35 1.50 x 10 ¹² 69.7 0 100 1.56 x 10 ¹⁰ 47.3

Example 2 – viscosity

Viscosity measurements were carried out in a double-jacketed autoclave reactor in which a heat transfer fluid circulates, with a capacity of 0.2 L, into which Jarylec ^® C101 oil was introduced. The reactor is cooled to -10°C and stirred magnetically. Then, HCFO-1233zdE was introduced by pressure difference. The reactor was then brought to the measurement temperature.

The viscosity measurement was then carried out, with a SOFRASER brand vibrating rod viscometer, model MIVI 9601. A camera made it possible to confirm the miscibility of the oil and the refrigerant under the measurement conditions and to check the immersion of the viscometer rod, before carrying out the measurement.

HCFO-1233zd E content 0% 10% 0% 10% T (°C) 20 20 0 0 Dynamic viscosity (cP) 6.0 3.9 12 6.5

For comparison, a viscosity measurement according to the ISO 3104 standard was carried out on the oil (0% HCFO-1233zd E) at 20°C. The value obtained is 6.5 cP.

Example 3 – flammability

A flash point measurement was carried out on a composition containing 90% by weight of Jarylec ^® C101 oil and 10% by weight of HCFO-1233zdE, as well as on a comparative composition containing 100% by weight of Jarylec ^® C101 oil.

The mixture was prepared at low temperature, under atmospheric pressure. It is homogeneous and liquid at room temperature and atmospheric pressure.

The flash point measurement was carried out according to standard ISO 3679 or ISO3680, “Pass/do not pass flash point test – rapid closed-cup equilibrium method. The standardized tests are carried out with the filling port left free, therefore open and breathing to the atmosphere, the cup being closed.

The tests were adapted according to the cases by blocking the filling port so as to be able to simulate an even more confined device during temperature equilibrium (2 minutes under standardized conditions). In this case, the tests are carried out with the cover closed.

The temperature range explored was up to 300°C.

HCFO-1233zd E content 0% 10% Flash point 138°C Not detected

Example 4 – heat transfer coefficient (two-phase immersion)

In order to carry out heat transfer coefficient measurements, a test device placed in a thermal regulation chamber is used to measure the performance of fluids by varying the ambient temperature. The test device includes a container with a heating element and a condenser. The condenser is located at the top of the container and is cooled by a chilled water loop. The heating element is a cylindrical resistor with a diameter of 15 mm and a height of 80 mm in a copper sheath, which is immersed vertically in a cylinder filled with saturated liquid in order to heat it. It can provide up to 15 W/cm ² . Eight temperature sensors are placed on the copper sheath to measure the surface temperature.

Two different mixtures of an oil whose properties, in particular viscosity, are close to those of Jarylec ^® C101 oil, and whose properties, in particular thermal conductivity (thermal conductivity greater than 0.05 W/(m ² .K) and dielectrics meet the specifications for this application, and HCFO-1233zdE were tested. The HCFO-1233zdE was introduced first avoiding any moisture entry or air pollution. The oil was added by gravity with a graduated cylinder. Miscibility and homogeneity were checked by sampling.

The cooling water temperature (10°C condenser temperature) and flow rate were set to the desired values. The ambient temperature was set at 26°C. Thermal power was increased from 0 to 90 W in 5 W increments and then decreased again for hysteresis detection. An average value of heat transfer coefficient was measured during the temperature rise: H= F/(T _w -T _sat ), with F the heat flux density, T _w the wall temperature, and T _sat the liquid saturation temperature of the measured composition.

HCFO-1233zdE (% weight) 30 60 30 60 60 F (W/cm ² ) 0.5 0.5 1.5 1.5 2.5 H (W/(m ² .°K)) 197 573 441 973 1548

Claims (13)

Use of a heat transfer composition comprising from 20% to less than 100% by weight of a refrigerant fluid comprising a compound chosen from halogenated hydrocarbons, perhalogenated compounds, fluorinated ketones, fluorinated ethers as well as combinations thereof, and more than 0% to 80% by weight of a dielectric fluid chosen from mineral dielectric oils, synthetic dielectric oils, and vegetable dielectric oils, and preferably from aromatic hydrocarbons chosen from alkylbenzenes, alkyldiphenylethanes, alkylnaphthalenes, methylpolyarylmethanes and combinations thereof, poly(alpha)olefins and polyol esters, for cooling a battery, the battery comprising energy storage cells immersed in the heat transfer composition, and the transfer composition of heat undergoing evaporation on contact with the energy storage cells. Use according to claim 1, wherein the heat transfer composition circulates in a heat transfer circuit. Use according to claim 2, in which the battery comprises one or more modules each comprising an enclosure in which energy storage cells are arranged, the enclosure(s) forming part of the heat transfer circuit. Use according to claim 2 or 3, wherein the heat transfer circuit is thermally coupled to a secondary circuit containing an additional transfer composition. Use according to claim 4, in which the secondary circuit is the air conditioning circuit of a vehicle; and/or is a reversible heat pump circuit. Use according to one of the preceding claims, in which the refrigerant comprises or is 1-chloro-3,3,3-trifluoropropene, preferably in form E, or is a binary mixture, preferably azeotropic, of 1-chloro -3,3,3-trifluoropropene in Z form and 1,1,1,2,3-pentafluoropropane, or 1,1,1,4,4,4-hexafluorobut-2-ene in Z form and 1 ,2-dichloroethylene in E form. Use according to one of the preceding claims, in which the battery is the battery of an electric or hybrid vehicle, preferably of an electric or hybrid automobile. Use according to the preceding claim, implemented when charging the vehicle battery, the vehicle battery being preferably fully charged in a period of less than or equal to 30 min, and preferably less than or equal to 15 min from its total discharge. Battery assembly, in particular for an electric or hybrid vehicle, comprising one or more modules each comprising an enclosure in which energy storage cells are arranged immersed in a heat transfer composition, the heat transfer composition comprising 20% less than 100% by weight of a refrigerant comprising a compound chosen from halogenated hydrocarbons, perhalogenated compounds, fluorinated ketones, fluorinated ethers as well as their combinations, and more than 0% to 80% by weight of a dielectric fluid, the battery assembly being configured such that the heat transfer composition undergoes evaporation to cool the battery. Battery assembly according to claim 9, comprising a heat transfer circuit in which the heat transfer composition circulates, the enclosure(s) of the module(s) being integrated into this heat transfer circuit. A battery assembly according to claim 10, wherein the heat transfer circuit comprises a pump; and/or wherein the heat transfer circuit comprises a heat exchanger to enable heat exchange of the heat transfer composition either with ambient air or with a heat transfer composition in a secondary circuit. Battery assembly according to one of claims 9 to 11, in which the refrigerant comprises or is 1-chloro-3,3,3-trifluoropropene, preferably in form E, or is a binary mixture, preferably azeotropic, 1-chloro-3,3,3-trifluoropropene in Z form and 1,1,1,2,3-pentafluoropropane, or 1,1,1,4,4,4-hexafluorobut-2-ene in Z and 1,2-dichloroethylene in E form. Method of regulating the battery temperature of the battery assembly according to one of claims 9 to 12, comprising cooling the energy storage cells by the heat transfer composition by partial evaporation of the transfer composition heat.