Cooling a battery by immersion in a composition that accompanies a change of state

Abstract

The present invention relates to the use of a heat transfer composition for cooling a battery, the heat transfer composition comprising from 20 weight percent to less than 100 weight percent of a refrigerant comprising a compound selected from the group consisting of halogenated hydrocarbons, perhalogenated compounds, fluoroketones, fluoroethers, and combinations thereof, and from greater than 0 weight percent to 80 weight percent of a dielectric fluid, the battery comprising an energy storage cell immersed in the heat transfer composition, and the heat transfer composition undergoing evaporation when in contact with the energy storage cell.

Description

Technical Field

[0001] This invention relates to the use of a heat transfer composition comprising at least one refrigerant and at least one dielectric fluid for cooling a battery. The invention is particularly applicable to batteries for electric or hybrid vehicles. Background Technology

[0002] In a variety of applications, particularly battery cooling, the need to dissipate high heat flux is essential. Liquid-gas phase change cooling has proven to be an effective solution for dissipating large amounts of heat while maintaining the battery temperature within its optimal range and ensuring a uniform system temperature.

[0003] In particular, the batteries of electric or hybrid vehicles deliver maximum output under specific operating conditions, especially within very specific temperature ranges. Therefore, in cold climates, the driving range of electric or hybrid vehicles becomes problematic, especially as the high heating requirements consume a large portion of the stored electrical energy. Furthermore, at low temperatures, the available power of the battery is low, which poses driving challenges. In addition, the cost of the battery significantly contributes to the overall cost of electric or hybrid vehicles.

[0004] Conversely, battery cooling is a primary safety concern. Various dielectric oils can be used to cool batteries in electric or hybrid vehicles. However, when rapid charging of the battery is required, a single-phase cooling system using, for example, dielectric oil alone is insufficient for effective battery cooling. In this case, a cooling system with a phase change in thermal composition must be envisioned. Fluids with higher volatility and lower viscosity, such as refrigerants, should be used. However, these fluids exhibit higher vapor pressures than those observed with dielectric oils, which may necessitate reinforcing the battery casing (and thus increasing its weight) to withstand the pressure. Furthermore, these fluids are more expensive than dielectric oils. They also have much higher densities than dielectric fluids, which could place a significant burden on the system.

[0005] In addition, it is important to use slightly flammable or non-flammable compositions near the battery to eliminate any risks associated with the safety of using these compositions.

[0006] Document FR 2 973 809 relates to the use of zeolite adsorbents for improving the thermal stability of oils subjected to temperature changes in coolant compositions.

[0007] Document FR 2 962 442 relates to stable compositions containing 2,3,3,3-tetrafluoropropylene for use in refrigeration and air conditioning.

[0008] Document US 2014 / 057826 relates to heat transfer compositions comprising at least one hydrochlorofluoroolefin, said at least one hydrochlorofluoroolefin being used in air conditioning, refrigeration and heat pump applications or for cleaning products, components, substrates or other articles containing substances to be cleaned.

[0009] Document WO 2019 / 242977 relates to fluid-insulated switchgear, which includes a fluid compartment filled with an electrically insulating fluid and an electrical conductor located in the fluid compartment and electrically insulated by the electrically insulating fluid.

[0010] Document WO 2019 / 162598 relates to the use of refrigerants containing 2,3,3,3-tetrafluoropropylene for maintaining the temperature of batteries in electric or hybrid vehicles within a certain temperature range.

[0011] Document WO 2019 / 162599 relates to the use of a refrigerant containing 2,3,3,3-tetrafluoropropylene for preheating the battery of an electric or hybrid vehicle from the start of vehicle movement.

[0012] Document WO 2019 / 197783 relates to a process for cooling and / or heating a body or fluid in a motor vehicle by means of a system comprising a vapor compression circuit (in which a first heat transfer composition circulates) and a secondary circuit (in which a second heat transfer composition circulates).

[0013] Documents WO 2020 / 011888, WO 2020 / 100152, WO 2020 / 007954, US 9 865907, US 10784 545, FR 3 037 727, FR 3 075 471, FR 3 085 542, FR 3 085 545, FR 3 085 547, FR 3085 556 and EP 3 499 634 describe systems for thermally regulating batteries through direct contact with fluids.

[0014] It is necessary to ensure the optimal operation of batteries, especially those in electric or hybrid vehicles, in order to provide high-performance batteries with long life and improved safety without increasing costs. Summary of the Invention

[0015] The present invention relates first to the use of a heat transfer composition for cooling a battery, the heat transfer composition comprising 20% ​​to less than 100% by weight of a refrigerant and greater than 0% to 80% by weight of a dielectric fluid, the refrigerant comprising a compound selected from halogenated hydrocarbons, perhalogenated compounds, fluoroketones, fluoroethers, and combinations thereof, the battery comprising an energy storage cell immersed in the heat transfer composition, and the heat transfer composition undergoing evaporation upon contact with the energy storage cell.

[0016] In some embodiments, the heat transfer composition circulates in a heat transfer loop.

[0017] In some embodiments, the battery includes one or more modules, each module including a housing in which an energy storage unit battery is disposed, the housing forming part of the heat transfer loop.

[0018] In some implementations, the heat transfer circuit is thermally coupled to a secondary circuit containing an additional transfer composition.

[0019] In some implementations, the secondary circuit is the vehicle's air conditioning circuit and / or a reversible heat pump circuit.

[0020] In some embodiments, the refrigerant comprises or is 1-chloro-3,3,3-trifluoropropylene, preferably in the E form, or is a binary mixture, preferably an azeotropic binary mixture, of 1,1,1,2,3-pentafluoropropane and 1-chloro-3,3,3-trifluoropropylene in the Z form, or of 1,1,1,4,4,4-hexafluorobut-2-ene in the Z form and 1,2-dichloroethylene in the E form.

[0021] In some embodiments, the dielectric fluid is selected from mineral dielectric oils, synthetic dielectric oils, and vegetable dielectric oils, and is preferably selected from aromatic hydrocarbons, poly(α-)olefins, and polyol esters, wherein the aromatic hydrocarbons are selected from alkylbenzenes, alkyl diphenyl ethanes, alkyl naphthalenes, methyl poly(poly)aryl methanes, and combinations thereof.

[0022] In some implementations, the battery is a battery for an electric or hybrid vehicle, preferably a battery for an electric or hybrid automobile.

[0023] In some implementations, this use is carried out during the charging of the vehicle's battery, which is preferably fully charged within a period of less than or equal to 30 minutes, and more preferably less than or equal to 15 minutes, from the start of its complete discharge.

[0024] The present invention also relates to battery assemblies, particularly battery assemblies for electric or hybrid vehicles, the battery assembly comprising one or more modules, each module comprising a housing in which an energy storage cell battery is disposed immersed in a heat transfer composition, the heat transfer composition comprising 20% ​​to less than 100% by weight of a refrigerant and greater than 0% to 80% by weight of a dielectric fluid, the refrigerant comprising a compound selected from halogenated hydrocarbons, fully halogenated compounds, fluoroketones, fluoroethers, and combinations thereof, the battery assembly being configured such that the heat transfer composition undergoes evaporation to cool the battery.

[0025] In some embodiments, the component includes a heat transfer loop in which a heat transfer composition circulates, and the module housing is incorporated into the heat transfer loop.

[0026] In some embodiments, the heat transfer circuit includes a pump; and / or the heat transfer circuit includes a heat exchanger to enable the heat transfer composition to exchange heat with ambient air or with a heat transfer composition in a secondary circuit.

[0027] In some embodiments, the refrigerant comprises or is 1-chloro-3,3,3-trifluoropropylene, preferably in the E form, or is a binary mixture, preferably an azeotropic binary mixture, of 1,1,1,2,3-pentafluoropropane and 1-chloro-3,3,3-trifluoropropylene in the Z form, or of 1,1,1,4,4,4-hexafluorobut-2-ene in the Z form and 1,2-dichloroethylene in the E form.

[0028] In some embodiments, the dielectric fluid is selected from mineral dielectric oils, synthetic dielectric oils, and vegetable dielectric oils; and is preferably selected from alkylbenzenes, alkyl diphenyl ethanes, alkyl naphthalenes, methyl polyaryl methanes and combinations thereof, poly(α-)olefins, and polyol esters.

[0029] The present invention also relates to a method for regulating the battery temperature of the battery assembly described above, the method comprising cooling the energy storage cell battery by means of partial evaporation of the heat transfer composition.

[0030] This invention enables the fulfillment of the aforementioned needs. This is because it ensures optimal operation of equipment, particularly batteries for electric or hybrid vehicles (especially traction batteries), to provide high-performance batteries with long lifespan and improved safety without increasing costs.

[0031] This is achieved by using a heat transfer composition comprising 20% ​​to less than 100% by weight of a refrigerant and more than 0% to 80% of a dielectric fluid, wherein the refrigerant is selected from halogenated hydrocarbons, perhalogenated compounds, fluoroketones, fluoroethers, and combinations thereof, wherein the energy storage cell of the battery is immersed in the heat transfer composition, and wherein the heat transfer composition undergoes evaporation upon contact with the energy storage cell.

[0032] This is because the combination of dielectric fluid and refrigerant allows the heat transfer properties to be maintained far better than those of liquid dielectric fluid.

[0033] Compared to using a refrigerant alone, this invention allows for reduced costs and weight without significantly degrading battery performance, lifespan, or safety.

[0034] In addition, the vapor pressure of the composition is generally lower than that of the refrigerant alone, which reduces the constraints on facility reinforcement.

[0035] Therefore, the present invention enables a general increase in battery efficiency and lifespan, especially during fast charging, without increasing costs.

[0036] Preferably, the refrigerant has a boiling point of less than 50°C, more preferably less than 30°C, and particularly less than 25°C or 20°C (at 1 bar). A relatively low boiling point can help mitigate the propagation of thermal runaway in the event of battery failure.

[0037] Preferably, the composition exhibits a strength greater than or equal to 10 at 25°C. 6 The volume resistivity is Ω·cm. Preferably, the composition exhibits a breakdown voltage greater than or equal to 20 kV at 20°C. From a safety perspective, this ensures that the dielectric properties of the composition are compatible with direct contact battery use.

[0038] The refrigerant allows for a reduction in the viscosity of the dielectric fluid and optionally makes the composition more volatile and therefore more efficient. The refrigerant also allows for a reduction in the liquid saturation temperature of the composition (compared to compositions containing only dielectric fluid) and improves the cooling efficiency of the battery. Compared to compositions containing only refrigerant, this invention allows for a reduction in constraints related to the pressure resistance of the facility.

[0039] Advantageously, the combination of refrigerant and dielectric fluid also makes it possible to obtain compositions that are slightly flammable or non-flammable. Attached Figure Description

[0040] [ Figure 1 [Illustration 1] is a diagram illustrating an embodiment of a battery assembly according to the present invention.

[0041] [ Figure 2 [Illustration 1] is a diagram illustrating an embodiment of a battery assembly according to the present invention.

[0042] [ Figure 3 [Illustration 1] is a diagram illustrating an embodiment of a battery assembly according to the present invention.

[0043] [ Figure 4 [Illustration 1] is a diagram illustrating an embodiment of a battery assembly according to the present invention.

[0044] [ Figure 5 [This is a graph showing the change in liquid saturation temperature of the heat transfer composition as a function of refrigerant content at a pressure of 1 bar (see the Examples section below). Temperature is expressed on the vertical axis (°C), and the dielectric fluid content is expressed on the horizontal axis (wt%). Detailed Implementation

[0045] The invention will now be described in more detail and in a non-limiting manner in the following description.

[0046] Heat transfer composition

[0047] The heat transfer composition according to the invention comprises at least one refrigerant and at least one dielectric fluid.

[0048] The term "refrigerant" is understood to mean a fluid that readily absorbs heat by evaporating at low temperatures and low pressures and readily releases heat by condensing at high temperatures and high pressures.

[0049] The refrigerant contains compounds selected from halogenated hydrocarbons, fully halogenated compounds, fluoroketones, fluoroethers, and combinations thereof.

[0050] The refrigerant may consist of one or more such compounds. Alternatively, it may also contain one or more other compounds selected from hydrocarbons (alkanes or alkenes, particularly propane, butane, isobutane, pentane, isopentane), CO2, and oxygen-containing hydrocarbons (particularly methoxymethane, ethoxyethane, and methyl formate).

[0051] Preferably, the refrigerant consists of C1, C2, C3, C4 and / or C5 compounds; more preferably, C1, C2, C3 and / or C4 compounds.

[0052] Among halogenated hydrocarbons, hydrofluorocarbons, hydrochlorofluorocarbons, hydrofluoroolefins, hydrochloroolefins, and hydrochlorofluoroolefins may be mentioned.

[0053] For example, the refrigerant can be selected 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), and 2,4,4,4-tetrafluorobut-1-ene (HFO-1354mfy). 1,1,2-Trifluoroethylene (HFO-1123), 2,3,3,3-Tetrafluoropropylene (HFO-1234yf), 1,3,3,3-Tetrafluoropropylene (HFO-1234ze, E or Z isomer, preferably E isomer), 1-Chloro-2,3,3,3-Tetrafluoropropylene (HCFO-1224yd, E or Z isomer, preferably Z isomer), 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, E or Z isomer, preferably E isomer), and combinations thereof.

[0054] Preferred compounds include, in particular, HCFO-1233zd (preferably in the E form), HFO-1336mzz (preferably in the Z form) and HCFO-1224yd (preferably in the Z form).

[0055] Perhalogenated compounds consist only of carbon atoms and halogen atoms. Examples include perfluorinated compounds such as dodecylfluoropentane, tetradecylfluorohexane, hexadecylfluoroheptane, and combinations thereof.

[0056] Among fluoroketones, examples include fluorinated monoketones, perfluorinated monoketones such as 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone, and combinations thereof.

[0057] In the context of fluoroethers, references are made to hydrofluoroethers such as methoxynonfluorobutane (HFE7100), ethoxynonfluorobutane (HFE-7200), 1-methoxyheptafluoropropane (HFE-7000), perfluoropolyethers, and combinations thereof.

[0058] The refrigerant may contain multiple compounds, such as two, three, four, or five as described above.

[0059] For example, a refrigerant may consist of (or be substantially composed of) the following:

[0060] -A mixture of HFO-1234yf and HFC-134a;

[0061] A mixture of -HFO-1336mzz(Z) and HCO-1130(E);

[0062] A mixture of HFO-1234ze(E) and HFC-227ea;

[0063] A mixture of HFO-1234yf, HFC-134a and HFC-152a;

[0064] A mixture of HFC-32, HFC-152a and HFO-1234ze(E);

[0065] A mixture of CO2, HFC-134a and HFO-1234ze(E);

[0066] -A mixture of HFC-32, HFO-1234ze(E) and butane;

[0067] A mixture of HFC-32, HFC-125 and HFO-1234ze(E);

[0068] A mixture of HFC-32, HFC-125, HFO-1234yf, HFC-134a and HFO-1234ze(E);

[0069] A mixture of HFC-32, HFC-125, HFO-1234yf and HFC-134a;

[0070] -A mixture of HFC-134a and HFO-1234ze(E);

[0071] A mixture of HFC-32, HFC-125 and HFO-1234yf;

[0072] -A mixture of HFC-32 and HFO-1234yf;

[0073] A mixture of CO2, HFC-32 and HFO-1234yf;

[0074] A mixture of HFC-32, HFC-134a and HFO-1234ze(E);

[0075] -A mixture of HFC-32, HFO-1234yf and HFC-152a;

[0076] -A mixture of HFC-32, HFO-1234yf and HFO-1234ze(E);

[0077] A mixture of HFC-32, HFC-125, HFC-134a and HFO-1234ze(E);

[0078] A mixture of HFC-32, HFC-125, HFC-134a and HFO-1234ze(E);

[0079] A mixture of CO2, HFC-32, HFC-125, HFO-1234yf and HFC-134a;

[0080] A mixture of HFC-32, HFC-125, HFO-1234ze(E) and HFC-227ea; and

[0081] -A mixture of HFC-32, propane and HFO-1234yf.

[0082] Therefore, the refrigerant can be a pure substance or a mixture. When it is a mixture, it is preferably an azeotropic or near-azeotropic mixture.

[0083] The preferred azeotropic composition is a refrigerant:

[0084] -R-513A (56% HFO-1234yf and 44% HFC-134a);

[0085] -R-513B (58.5% HFO-1234yf and 41.5% HFC-134a);

[0086] -R-514A (74.7% HFO-1336mzz(Z) and 25.3% HCO-1130(E));

[0087] -R-515A (88% HFO-1234ze(E) and 12% HFC-227ea);

[0088] -R-516A (77.5% HFO-1234yf, 8.5% HFC-134a and 14% HFC-152a).

[0089] Alternatively, in some embodiments, non-azeotropic compositions and, in particular, refrigerants such as:

[0090] -R-444A (12% HFC-32, 5% HFC-152a and 83% HFO-1234ze(E));

[0091] -R-444B (41.5% HFC-32, 10% HFC-152a and 48.5% HFO-1234ze(E));

[0092] -R-445A (6% CO2, 9% HFC-134a and 85% HFO-1234ze(E));

[0093] -R-446A (68% HFC-32, 29% HFO-1234ze(E) and 3% butane);

[0094] -R-447A (68% HFC-32, 3.5% HFC-125 and 28.5% HFO-1234ze(E));

[0095] -R-447B (68% HFC-32, 8% HFC-125 and 24% HFO-1234ze(E));

[0096] -R-448A (26% HFC-32, 26% HFC-125, 20% HFO-1234yf, 21% HFC-134a and 7% HFO-1234ze(E));

[0097] -R-449A (24.3% HFC-32, 24.7% HFC-125, 25.3% HFO-1234yf and 25.7% HFC-134a);

[0098] -R-449B (25.2% HFC-32, 24.3% HFC-125, 23.2% HFO-1234yf and 27.3% HFC-134a);

[0099] -R-449C (20% HFC-32, 20% HFC-125, 31% HFO-1234yf and 29% HFC-134a);

[0100] -R-450A (42% HFC-134a and 58% HFO-1234ze(E));

[0101] -R-451A (89.8% HFO-1234yf and 10.2% HFC-134a);

[0102] -R-451B (88.8% HFO-1234yf and 11.2% HFC-134a);

[0103] -R-452A (11% HFC-32, 59% HFC-125 and 30% HFO-1234yf);

[0104] -R-452B (67% HFC-32, 7% HFC-125 and 26% HFO-1234yf);

[0105] -R-452C (12.5% ​​HFC-32, 61% HFC-125 and 26.5% HFO-1234yf);

[0106] -R-454A (35% HFC-32 and 65% HFO-1234yf);

[0107] -R-454B (68.9% HFC-32 and 31.1% HFO-1234yf);

[0108] -R-454C (21.5% HFC-32 and 78.5% HFO-1234yf);

[0109] -R-455A (3% CO2, 21.5% HFC-32 and 75.5% HFO-1234yf);

[0110] -R-456A (6% HFC-32, 45% HFC-134a and 49% HFO-1234ze(E));

[0111] -R-457A (18% HFC-32, 70% HFO-1234yf and 12% HFC-152a);

[0112] -R-459A (68% HFC-32, 26% HFO-1234yf and 6% HFO-1234ze(E));

[0113] -R-459B (21% HFC-32, 69% HFO-1234yf and 10% HFO-1234ze(E));

[0114] -R-460A (12% HFC-32, 52% HFC-125, 14% HFC-134a and 22% HFO-1234ze(E));

[0115] -R-460B (28% HFC-32, 25% HFC-125, 20% HFC-134a and 27% HFO-1234ze(E));

[0116] -R-460C (2.5% HFC-32, 2.5% HFC-125, 46% HFC-134a and 49% HFO-1234ze(E));

[0117] -R-460A (12% HFC-32, 52% HFC-125, 14% HFC-134a and 22% HFO-1234ze(E));

[0118] -R-463A (6% CO2, 36% HFC-32, 30% HFC-125, 14% HFO-1234yf and 14% HFC-134a);

[0119] -R-464A (27% HFC-32, 27% HFC-125, 40% HFO-1234ze(E) and 6% HFC-227ea); and

[0120] -R-465A (21% HFC-32, 7.9% propane and 71.1% HFO-1234yf).

[0121] All percentages shown are by weight.

[0122] In some preferred embodiments, the refrigerant comprises HCFO-1233zd in the form of E or Z, more preferably in the form of E.

[0123] Preferably, the heat transfer composition according to the invention comprises essentially a single compound as a refrigerant. In this case, the refrigerant is preferably in the form of E or Z, and more preferably in the form of E, HFO-1233zd.

[0124] Impurities may be present in up to, for example, 1% by weight.

[0125] The refrigerant may specifically include, by weight:

[0126] - At least 99.5%, preferably at least 99.7%, more preferably at least 99.8% of HCFO-1233zd(E);

[0127] - HFC-245fa at a concentration of less than or equal to 500 ppm, preferably 1 to 500 ppm, more preferably 2 to 300 ppm;

[0128] - HFO-1234ze (E or Z) at a content of less than or equal to 100 ppm, preferably 1 to 100 ppm, more preferably 2 to 50 ppm;

[0129] -HCFO-1233zd(Z) at a content of less than or equal to 100 ppm, preferably 1 to 100 ppm, more preferably 2 to 50 ppm.

[0130] Other preferred compositions are:

[0131] - A mixture, preferably a quasi-azeotropic or azeotropic composition, consisting of (or substantially consisting of) HCFO-1233zd(E) and HFC-245eb;

[0132] - A mixture consisting of (or substantially consisting of) HFO-1366mzz(Z) and HCO-1130(E), preferably a quasi-azeotropic or azeotropic composition, and more preferably refrigerant R-514A.

[0133] The refrigerant according to the invention may particularly have a liquid viscosity of 0.1 cP to 2 cP at 20°C, preferably 0.2 cP to 0.9 cP at 20°C. The viscosity can be measured according to the method shown in Example 2 below.

[0134] The refrigerant according to the invention can particularly have a liquid saturation temperature of 0 to 50°C, preferably 10 to 30°C, and especially 15 to 25°C at 1 bar.

[0135] The refrigerant according to the invention may particularly have a density of 1 to 1.7, preferably 1 to 1.5, and more preferably 1 to 1.4 at 20°C.

[0136] The refrigerant according to the invention may in particular have a liquid saturation pressure of less than or equal to 2 bar at 30°C.

[0137] Within the meaning of this invention, the term "dielectric fluid" is understood to mean a fluid that is non-conductive (or only slightly conductive) but allows the application of electrostatic forces, generally oil.

[0138] The term "oil" is understood to mean a fatty substance that is liquid at ambient temperature and immiscible with water. Oil is a fatty liquid of plant, mineral, or synthetic origin. It may be selected from oils belonging to categories I through V as defined in the API classification (or their equivalents according to the ATIEL classification).

[0139] Insulating (dielectric) oil has the properties of a heat exchange fluid, and therefore participates in heat transfer just like a refrigerant.

[0140] The oil included in the heat transfer composition may be particularly selected from mineral dielectric oils, synthetic dielectric oils (which may optionally be bio-based) and plant dielectric oils, as well as combinations thereof.

[0141] 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 from the Nytro family (particularly Nytro Taurus, NytroLibra, Nytro 4000X, and Nytro 10XN) sold by Nynas and Dalia sold by Shell.

[0142] Mineral dielectric oils may preferably be paraffin oils (i.e., saturated linear or branched hydrocarbons), such as Nytro Taurus oil sold by Nynas and Dalia oil sold by Shell, or cycloalkane oils (i.e., cyclic alkanes), such as Nytro Libra and Nytro 10XN oils sold by Nynas, aromatic compounds (i.e., unsaturated cyclic hydrocarbons containing one or more rings characterized by alternating double and single bonds) and non-hydrocarbon compounds.

[0143] Preferably, the dielectric fluid is optionally a bio-based synthetic dielectric oil. Preferably, it may be an aromatic hydrocarbon, an aliphatic hydrocarbon, a silicone oil, an ester, and a polyester, especially a polyol ester, and a mixture of two or more of them in all proportions.

[0144] In aromatic hydrocarbons, alkylbenzenes, alkyl diphenyl ethanes (e.g., phenylxylenyl ethane (PXE), phenylethyl phenyl ethane (PEPE), monoisopropyl biphenyl (MIPB), 1,1-diphenyl ethane (1,1-DPE)), alkyl naphthalenes (e.g., diisopropyl naphthalene (DIPN)), methyl polyaryl methanes (e.g., benzyl toluene (BT) and dibenzyl toluene (DBT), and mixtures thereof) may be mentioned in a non-limiting manner. In said aromatic hydrocarbons, it should be understood that at least one ring is aromatic, and one or more other rings optionally present may be partially or completely unsaturated. Particular references may be made to Arkema under the name... Dielectric fluids sold by Soltex Inc., and SAS 60E from JX Nippon Chemical Texas Inc.

[0145] In aliphatic hydrocarbons, references may be made in a non-limiting manner to alkanes, poly(α-)olefins (PAOs) such as polyisobutylene (PIB), or vinylidene olefins, such as those sold by, for example, Soltex Inc.

[0146] Alkanes may particularly contain at least 8 carbon atoms, for example 8 to 22 carbon atoms, preferably 15 to 22 carbon atoms.

[0147] PAO can be selected from Class IV and is obtained, for example, from a monomer containing 4 to 32 carbon atoms, such as octene or decene. The weight-average molecular weight of PAO can vary considerably. Preferably, the weight-average molecular weight of PAO is less than 600 Da. The weight-average molecular weight range of PAO can also be 100 to 600 Da, 150 to 600 Da, or even 200 to 600 Da. For example, it exhibits a range of 1.5 to 8 mm when measured at 100°C. 2 The kinematic viscosity of PAO (measured according to standard ASTM D445 at 100°C) is 1 / s by Ineos under the trade name. 162. 164. 166 and 168 Commercial Sales.

[0148] In the context of silicone oils, linear silicone oils of the polydimethylsiloxane type may be mentioned in a non-limiting manner, such as those described by Wacker under the name […]. Those sold by AK.

[0149] In the context of synthetic esters, phthalic acid-type esters may be mentioned in a non-limiting manner, such as dioctyl phthalate (DOP) or diisononyl phthalate (DINP) (e.g., sold by BASF).

[0150] It may also be mentioned in a non-limiting manner as a mixture of polyols and organic acids, particularly those selected from saturated or unsaturated C4 to C5 groups. 22 Esters formed by the reaction of organic acids with each other. As non-limiting examples of such organic acids, undecanoic acid, heptanoic acid, octanoic acid, palmitic acid, and mixtures thereof may be mentioned. Among the polyols that can be used to synthesize the above esters, as non-limiting examples, pentaerythritol used to synthesize oils Mivolt DF7, Midel 7131, and Mivolt DFK from M&I Materials may be mentioned.

[0151] Esters can be, for example, of formula R a -C(O)-O-([C(R)2] n -O) s -C(O)-R b The diester, wherein each R independently represents a hydrogen atom or a linear or branched C1-C5 alkyl group, particularly methyl, ethyl, or propyl, especially methyl; the value of s is 1, 2, 3, 4, 5, or 6; the value of n is 1, 2, or 3; it should be understood that when s is not 1, the n exponent can be the same or different; and R a and R b—Whether identical or different—each independently represents a saturated or unsaturated and linear or branched hydrocarbon group exhibiting a linear sequence of 6 to 18 carbon atoms. Preferably, when s and n are the same and have a value of 2, at least one of the R groups represents a linear or branched C1-C5 alkyl group; and when s has a value of 1 and n has a value of 3, at least one of the R groups bonded to the β-position carbon of the ester functional oxygen atom represents a hydrogen atom.

[0152] Synthetic esters produced by the reaction between polyols and organic acids are, for example, Midel7131 from M&I Materials or esters from the Nycodiel series from Nyco.

[0153] In the context of natural esters and vegetable oils, references may be made in a non-limiting manner to products derived from oily seeds or other natural sources. As an example, and in a non-limiting manner, reference may be made to FR 3 sold by Cargill. TM Or perhaps Envirotemp TM Alternatively, there is Midel EN 1215, which is sold by M&I Materials.

[0154] Polyalkylene glycols (PAGs) can also be used, particularly those obtained by polymerization or copolymerization of epoxides containing 2 to 8 carbon atoms, especially 2 to 4 carbon atoms.

[0155] The heat transfer composition according to the invention may contain one or more oils, such as two, three, four or five oils.

[0156] The preferred dielectric fluid is a polyol ester made from pentaerythritol.

[0157] Another preferred dielectric fluid is a poly(α-)olefin (PAO), which mainly comprises (that is, up to more than 50% by weight) isoparaffins containing 4 to 32 carbon atoms. This fluid belongs to Group IV of the API classification.

[0158] Preferably, the heat transfer composition according to the invention comprises a single dielectric fluid.

[0159] The dielectric fluid may in particular have a viscosity of 1 to 60 cP at 20°C according to standard ISO 3104.

[0160] When measured by boiling point determination, the dielectric fluid may have a boiling point greater than 30°C.

[0161] The dielectric fluid may be present in the composition in an amount greater than 0 wt% to 80 wt%, preferably greater than 0 wt% to 65 wt%, and even more preferably 10 wt% to 45 wt%, relative to the total weight of the heat transfer composition.

[0162] For example, the content relative to the total weight of the heat transfer composition may be greater than 0 wt% to 5 wt%; or 5 wt% to 10 wt%; or 10 wt% to 15 wt%; or 15 wt% to 20 wt%; or 20 wt% to 25 wt%; or 25 wt% to 30 wt%; or 30 wt% to 35 wt%; or 35 wt% to 40 wt%; or 40 wt% to 45 wt%; or 45 wt% to 50 wt%; or 50 wt% to 55 wt%; or 55 wt% to 60 wt%; or 60 wt% to 65 wt%; or 65 wt% to 70 wt%; or 70 wt% to 75 wt%; or 75 wt% to 80 wt%.

[0163] The refrigerant may be present in the composition in an amount of 20% to less than 100% by weight, preferably 35% to less than 100% by weight, and more preferably 55% to 90% by weight, relative to the total weight of the heat transfer composition.

[0164] For example, the content relative to the total weight of the heat transfer composition may be 20% to 25% by weight; or 25% to 30% by weight; or 30% to 35% by weight; or 35% to 40% by weight; or 40% to 45% by weight; or 45% to 50% by weight; or 50% to 55% by weight; or 55% to 60% by weight; or 60% to 65% by weight; or 65% to 70% by weight; or 70% to 75% by weight; or 75% to 80% by weight; or 80% to 85% by weight; or 85% to 90% by weight; or 90% to 95% by weight; or 95% to less than 100% by weight.

[0165] In some embodiments, the heat transfer composition according to the invention comprises a polyol ester prepared from pentaerythritol and at least one fluorinated or chlorofluorocarbon, wherein the fluorinated or chlorofluorocarbon is, for example in a non-limiting manner, hydrofluoropropane, hydrofluoropropylene, hydrochlorofluoropropane, hydrochlorofluoropropylene, and mixtures thereof in all proportions thereof.

[0166] In other embodiments, the heat transfer composition according to the invention comprises a poly(α-)olefin (PAO) and at least one fluorinated or chlorofluorocarbon, said fluorinated or chlorofluorocarbon being, for example in a non-limiting manner, hydrofluoropropane, hydrofluoropropylene, hydrochlorofluoropropane, hydrochlorofluoropropylene, and mixtures thereof in all proportions thereof.

[0167] Preferably, the heat transfer composition according to the invention comprises HCFO-1233zd (preferably in the E form) and a polyol ester made from pentaerythritol. More preferably, the heat transfer composition according to the invention consists essentially, actually, or even entirely of HCFO-1233zd (preferably in the E form) and a polyol ester made from pentaerythritol.

[0168] Preferably, the heat transfer composition according to the invention comprises HCFO-1233zd (preferably in the E form) and poly(α-)olefin (PAO). More preferably, the heat transfer composition according to the invention consists essentially, practically, or even entirely of HCFO-1233zd (preferably in the E form) and poly(α-)olefin (PAO). It may also consist essentially, or entirely of HFC-245eb, PAO, and HCFO-1233zd in the Z form. It may also consist essentially, or entirely of PAO and HFO-1336mzz in the Z form. It may also consist essentially, or entirely of PAO, HFO-1336mzz in the Z form, and HCO-1130 in the E form.

[0169] Compositions that can be used in the context of this invention may additionally include one or more additives and / or fillers, selected in a non-limiting manner from antioxidants, passivators, pour point depressants, decomposition inhibitors, flavorings and tastes, colorants, preservatives, and mixtures thereof. The presence of decomposition inhibitors is particularly preferred.

[0170] Among the antioxidants that may be advantageously used in compositions, non-limiting examples include phenolic antioxidants such as butylated hydroxytoluene, butylated hydroxyanisole, tocopherol, and acetates (esters) of these phenolic antioxidants; amine antioxidants such as phenyl-α-naphthylamine; diamine antioxidants such as N,N'-bis(2-naphthyl)-p-phenylenediamine; ascorbic acid and its salts, esters of ascorbic acid, alone or in mixtures of two or more of them, or in mixtures with other components such as green tea extract or coffee extract.

[0171] A particularly suitable antioxidant is available from Brenntag under the brand name. Commercially purchased antioxidants.

[0172] The passivating agents that can be used in the context of this invention are advantageously selected from triazole derivatives, benzimidazole, imidazole, thiazole, or benzothiazole. As examples and in a non-limiting manner, dioctylaminomethyl-2,3-benzotriazole and 2-dodecyl dithioimidazole may be mentioned.

[0173] Among the pour point depressants that may exist, as non-limiting examples, fatty acid esters of sucrose or acrylic polymers, such as poly(alkyl methacrylate) or poly(alkyl acrylate), may be mentioned.

[0174] The preferred acrylic polymer is one with a molecular weight of 50,000 g·mol⁻¹. -1 and 500,000 g.mol -1 Those in between. Examples of these acrylic polymers include polymers that may contain linear alkyl groups comprising 1 to 20 carbon atoms.

[0175] Among them, as non-limiting examples, 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(tetrazyl acrylate), poly(tetrazyl methacrylate), poly(pentadecanyl acrylate), poly(pentadecanyl methacrylate), poly(heptadecyl acrylate) and poly(heptadecyl methacrylate) may be mentioned.

[0176] Examples of this pour point depressant are available commercially under the trade name Aclube from Sanyo Chemical Industries Ltd.

[0177] According to a very particularly preferred aspect, the decomposition inhibitor is present as an additive. The decomposition inhibitor may be particularly selected from carbodiimide derivatives, such as diphenylcarbodiimide, xylylcarbodiimide, bis(isopropylphenyl)carbodiimide, or bis(butylphenyl)carbodiimide; and from phenyl glycidyl ethers or esters, alkyl glycidyl ethers or esters, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate, anthraquinone family compounds such as β-methylanthraquinone sold under the name "BMAQ", epoxide derivatives such as vinylcyclohexene diepoxide, 3,4-epoxy-6-methylcyclohexylmethyl 3,4-epoxy-6-methylhexane carboxylate, phenolic varnish-type epoxy resins, bisphenol A diglycidyl ether epoxy resins, such as BADGE or CEL 2021P, which are particularly available from Whyte Chemicals.

[0178] The total amount of additives preferably does not exceed 5% by weight, particularly 4% by weight, more particularly 3% by weight, and very particularly 2% by weight, or even 1% by weight, of the heat transfer composition.

[0179] The compositions according to the invention can be prepared in any manner known to those skilled in the art, for example by simply mixing the various components of the compositions according to the invention.

[0180] In some embodiments, the heat transfer composition contains impurities. When present, they may comprise less than 1%, preferably less than 0.5%, preferably less than 0.1%, preferably less than 0.05%, and most preferably less than 0.01% (by weight) relative to the heat transfer composition.

[0181] The selection of various components is not limiting, provided that the heat transfer composition according to the invention exhibits the properties (thermal conductivity, viscosity, resistivity, breakdown voltage, etc.) required for the target application. Preferably, the volume resistivity at 25°C is greater than or equal to 10. 6 Ω.cm, 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 resist the flow of electric current. In other words, volume resistivity is an indicator of the dielectric properties of a composition. Volume resistivity is measured according to standard IEC 60247.

[0182] For example, this volume resistivity can be as high as 10. 6 Up to 5×10 6 Ω.cm; or 5×10 6 Up to 10 7 Ω.cm; or 10 7 Up to 5×10 7 Ω.cm; or from 5×10 7 Up to 10 8 Ω.cm; or from 10 8 Up to 5×10 8 Ω.cm; or from 5×10 8 Up to 10 9 Ω.cm; or greater than 10 9 Ω.cm.

[0183] Furthermore, the heat transfer composition according to the invention preferably exhibits a breakdown voltage greater than or equal to 20 kV, more preferably greater than or equal to 20 kV, more preferably greater than or equal to 30 kV, more preferably greater than or equal to 50 kV, and more preferably greater than or equal to 100 kV at 20°C. The term "breakdown voltage" is understood to mean the minimum voltage required to make a portion of an insulator conductive. Therefore, this parameter is also an indicator of the dielectric properties of the composition. The breakdown voltage is measured according to standard IEC 60156.

[0184] For example, the breakdown voltage of the composition according to the invention at 20°C 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.

[0185] The heat transfer composition according to the invention can also exhibit a liquid saturation temperature of 20 to 80°C, preferably 30 to 70°C, at a pressure of 1 bar. For example, this temperature can be between 20 and 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 50 to 55°C; or 55 to 60°C; or 60 to 65°C; or 65 to 70°C; or 70 to 75°C; or 75 to 80°C.

[0186] According to standard ISO 3104, the heat transfer composition according to the invention can particularly have a viscosity of 0.1 to 20 cP at 20°C.

[0187] The heat transfer composition according to the invention is preferably slightly flammable (that is, exhibiting a high flash point, for example greater than 150°C, or greater than 200°C, or greater than 250°C, or greater than 300°C according to standards ISO 3679 and ISO 3680), or more preferably non-flammable.

[0188] Uses of heat transfer compositions

[0189] refer to Figure 1 The battery 402 can supply power to at least one motor 404, particularly a vehicle engine. The vehicle is preferably an automobile, but may also be construction machinery, scooters, motorcycles, trucks, ships, aircraft, etc.

[0190] A battery may include a group of energy storage units (or batteries), which may be grouped together in single or multiple modules. Each module may contain multiple batteries arranged in a sealed housing. Each module housing may be configured to hold the batteries in a fixed manner.

[0191] A battery may comprise the same or different modules. These modules may be assembled together mechanically and / or electrically to form a battery. The modules may be electrically connected in series or parallel.

[0192] Each housing may include, for example, an upper portion and a lower portion joined together by welding, adhesive bonding or threaded connection.

[0193] For example, the cell unit may be cylindrical. Each module may include 2 to 200 cell units, preferably 4 to 100 cell units, more preferably 6 to 50 cell units. For example, in each module, the cell units may be arranged in N rows, with M cell units in each row. N may have a value of, for example, 1 to 10, such as a value of 2. M may have a value of, for example, 1 to 60, and may be a multiple of 3 (i.e., 3, 6, 12, 18, 30, etc.). In some embodiments, the cell units may be ordered according to the three-dimensional arrangement in each module, wherein N x M cell units are stacked in P layers. Then, the number of layers P may have a value of, for example, 2 to 5. Alternatively, a single layer may exist.

[0194] For example, the cell unit can be a rechargeable nickel-cadmium (NiCd), nickel metal hydride (Ni-MH), or lithium-ion (Li-ion) cell unit.

[0195] Each casing can be made, for example, of plastics, particularly polystyrene, polyvinyl chloride, polycarbonate, polyethylene, polypropylene, acrylic polymers, and especially polymethyl methacrylate, phenolic resins, etc. Alternatively, it can be made of metallic materials such as aluminum.

[0196] The heat transfer composition is used to cool a battery. This cooling is achieved by placing the heat transfer composition in direct contact with the battery's energy storage cell, wherein the heat transfer composition at least partially changes its state (undergoes evaporation) upon contact with the cell. In other words, the energy storage cell is immersed in the heat transfer composition.

[0197] The term "immersion" should be understood to mean that the cell unit is in contact with the heat transfer composition. More specifically, the outer surfaces of the cell unit are in contact with the heat transfer composition. Preferably, they are in contact with the heat transfer composition, which is in a substantially liquid form.

[0198] Therefore, the cells can be arranged in a heat transfer composition bath. The heat transfer composition can occupy the entire internal space of the module between the cell and the housing wall, or preferably provide a gaseous top space. Preferably, the entire surface of the cell in the housing is in contact with the composition in liquid form.

[0199] Alternatively, the surface of the cell can be covered with a liquid film obtained by appropriate means (spraying, projecting, spraying, etc.) and / or by special treatment of the cell surface.

[0200] For example, the heat transfer composition can be sprayed onto the cell unit using unidirectional or multidirectional nozzles. These nozzles can be arranged, for example, between the cell units to project the heat transfer composition onto the sides of the cell units. Alternatively, they can be placed above the cell units to project the heat transfer composition onto the upper surface of the cell units. The composition can be projected as a jet, dripped, or misted. The composition can be collected in a tank and recycled by a pump. A heat exchanger and / or heating device (e.g., a resistor) can be arranged in the tank, or upstream or downstream of the pump, to supply heat to or remove heat from the composition. In this alternative form, the operation of bringing the liquid composition into contact with the surface of the cell unit can be performed only when it is necessary to regulate the temperature of the cell. At other times, and particularly when the cell is not in operation, the surface of the cell unit may not be in contact with the heat transfer composition.

[0201] Optionally, the surface of the cell may be coated with a hydrophilic film to allow a liquid layer of the heat transfer composition to be distributed on the surface of the cell. For example, a nanostructured SiO2 film may be used. Alternatively, filamentous or fibrous structures (including one or more rovings, or woven or nonwoven fabrics), or aggregated metal powder, may be arranged on the surface of the cell to allow a liquid layer of the heat transfer composition to be distributed on the surface of the cell via capillary action.

[0202] The heat transfer composition evaporates completely or partially when in contact with the cell unit (in order to cool them).

[0203] Preferably, the state change is partial: the dielectric fluid remains essentially liquid, while the refrigerant undergoes a complete or partial state change.

[0204] This allows for the maximum utilization of the thermal properties of the heat transfer composition. This is because cooling through direct contact between the battery's cell and the heat transfer composition is useful in the case of rapid battery charging, which involves the latter's rapid heating. This allows the temperature to be maintained uniformly within its optimal operating range.

[0205] The heat transfer composition is contained in a device adapted to exchange heat between the composition and a cell of a battery, and preferably also with a secondary source.

[0206] This device, together with the battery itself, constitutes the battery assembly according to the invention.

[0207] The auxiliary source can be ambient air or another heat transfer composition. When ambient air is involved, one or more fans can be used to increase heat exchange with it.

[0208] The heat transfer composition can be static or cyclic.

[0209] If it is static, the device includes a housing of individual cells containing batteries, and a heat transfer composition in contact with these individual cells. The heat transfer composition exchanges heat with the environment or another heat transfer composition via the housing itself. Therefore, the inner and / or outer walls of the housing may include heat dissipation elements, such as fins or another embossed structure, to facilitate heat exchange with the environment or another heat transfer composition. Preferably, the heat transfer composition may exchange heat with another heat transfer composition via a heat exchanger located in the housing, or directly via the walls of the housing, or via plates or channels on the walls of the housing.

[0210] For example, a condenser can be placed in the upper wall of the housing. Thus, the heat transfer composition undergoing evaporation while cooling the cell can be condensed in this condenser to return to a liquid form. This condenser allows for heat exchange with ambient air or with other heat transfer compositions. The condenser may include channels placed in the upper wall of the housing. Ridges, spikes, or other protrusions may facilitate the condensing heat transfer composition dripping downwards to the lower part of the housing.

[0211] The pressure inside the enclosure can vary depending on the temperature inside the enclosure. The pressure inside the enclosure can, for example, be maintained at less than 5 bar, or less than 4 bar, or less than 2 bar.

[0212] When the heat transfer composition circulates, the device includes a main heat transfer circuit, such as... Figure 1 As shown in the image.

[0213] The flow rate of the heat transfer composition in the main circuit can be 0 to 100 l / min, preferably 5 to 50 l / min.

[0214] Each module's housing may be provided with at least one fluid inlet and at least one fluid outlet, so that the heat transfer composition can pass through the housing, and the cell unit is preferably completely immersed in the heat transfer composition.

[0215] To avoid thermal shock, the temperature of the heat transfer composition at the inlet of the housing is preferably greater than or equal to 10°C, for example, between about 20°C and about 30°C.

[0216] To ensure better uniformity of thermal regulation of the battery, it is preferable that the absolute value of the temperature slip (the difference between the temperature of the heat transfer composition at the outlet of the casing and the temperature of the heat transfer composition at the inlet of the casing) is less than or equal to 10°C, preferably less than or equal to 5°C, more preferably less than or equal to 2°C, and even more preferably less than or equal to 1°C.

[0217] The modules can be fluidly connected in series or in parallel with respect to the heat transfer composition.

[0218] Refer again Figure 1The main heat transfer loop can be configured to deliver a heat transfer composition originating from at least one heat exchanger 408, 408' to the battery 402, and again from the battery 402 to at least one heat exchanger 408, 408'. The module housing is incorporated into this main loop. Circulation in the main loop can be achieved via convection. The main loop may also include one or more conduits for supplying the heat transfer composition to the battery and for collecting it; and possibly for transporting it between modules of the battery. Alternatively, the module housing may be in direct contact to allow for corresponding fluid inlets and outlets of the assembled modules. In this case, a seal may be provided between the assembled inlets and outlets.

[0219] When multiple fluid inlets and / or multiple fluid outlets are provided in each housing, the dispenser and collector may be attached to or incorporated into the housing. In some embodiments, portions of the dispenser and collector may be formed in the housing itself so that, when the respective housings are assembled, the heat transfer composition can be collected and dispensed from one module to another.

[0220] When the heat transfer composition is used to cool the battery, it evaporates completely or preferably partially as it passes through the casing.

[0221] Preferably, the state changes between a completely liquid composition and a two-phase liquid-vapor composition when passing through the battery, and then becomes a completely liquid composition again before returning to the battery (within the heat exchangers 408, 408').

[0222] The delivery of the heat transfer composition in the main circuit can be provided 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 vapor compression circuit.

[0223] The heat exchanger 408 is specifically designed as a radiator to ensure heat exchange with ambient air.

[0224] Alternatively, heat exchanger 408' couples the primary loop to the secondary loop, in which an additional heat transfer composition circulates, exchanging heat with another source (e.g., ambient air).

[0225] The additional heat transfer composition may be the same as or different from the heat transfer composition. For example, the additional heat transfer composition may be a refrigerant as described above, which is not mixed with dielectric fluids. For example, the composition may contain HFO-1234yf, and, if suitable, in combination with one or more lubricants and other additives. Alternatively, it may be, for example, a mixture of water and ethylene glycol.

[0226] The secondary circuit can be a refrigeration circuit, including a compressor, pressure reducer, evaporator and condenser; or it can be a simple heat exchange circuit without a compressor.

[0227] An expansion valve (e.g., an electronic expansion valve) may be located upstream of the heat exchanger 408' in the secondary circuit.

[0228] A pump can be provided in this secondary circuit to circulate additional heat transfer composition.

[0229] The additional heat transfer composition may optionally undergo a complete or partial change of state as it passes through heat exchanger 408'. Thus, if the heat transfer composition is cooled in heat exchanger 408', the additional heat transfer composition is correspondingly heated and may completely or partially evaporate (e.g., from a completely liquid state to a two-phase liquid-vapor state). Conversely, if the heat transfer composition is heated in heat exchanger 408', the additional heat transfer composition is correspondingly cooled and may completely or partially condense (e.g., from a two-phase liquid-vapor state to a completely liquid state).

[0230] Optionally, the secondary circuit may be reversible (that is, it may cool or heat the heat transfer composition in contact with the battery depending on the operating mode).

[0231] The heat exchanger 408′ that can exchange heat with other heat transfer compositions can be, for example, co-current or preferably counter-current.

[0232] The term "countercurrent heat exchanger" is understood to mean a heat exchanger in which heat is exchanged between a first fluid and a second fluid, with 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.

[0233] For example, a counter-current heat exchanger includes a device in which the flow of a first fluid and the flow of a second fluid are in opposite or nearly opposite directions. A counter-current heat exchanger also includes an exchanger operating in a cross-flow mode with a counter-current tendency.

[0234] Heat exchangers can be particularly those with U-tubes, horizontal or vertical tube bundles, spiral tubes, plates or fins.

[0235] The additional heat transfer composition itself can exchange heat with the environment via a separate heat exchanger. It can also optionally be used to heat or cool the air in the vehicle's passenger compartment. Therefore, heat dissipated through the battery can be absorbed by the vehicle's air conditioning circuit.

[0236] For this purpose, the secondary circuit may include various branches with separate heat exchangers in which additional heat transfer compositions may or may not circulate, depending on the operating mode. Optionally, alternatively, or additionally, the secondary circuit may include means for changing the circulation direction of the additional heat transfer compositions, such as including one or more three-way or four-way valves.

[0237] The main circuit may include a tank for storing excess heat transfer composition in liquid form.

[0238] The secondary circuit may include a vessel for storing excess additional heat transfer composition in liquid form.

[0239] When the main circuit is equipped with a pump, a protective device can be provided, for example, upstream of the pump, to ensure that only liquid is pumped to the battery. This is because, depending on external conditions (e.g., when the vehicle is hot due to weather conditions upon startup), the heat transfer composition can be two-phase upstream of the pump, particularly at the tank outlet. The protective device may include a bypass system, particularly between the tank and the pump, with valves, pressure sensors, and temperature sensors. Filters and dryers can be provided to capture impurities and moisture, respectively.

[0240] A third circuit containing another additional heat transfer composition may be provided, which is thermally connected to the secondary circuit via a heat exchanger. This third circuit may be specifically dedicated to collecting heat dissipated by the vehicle's engine and / or electrical components.

[0241] It can provide two or more main circuits that can operate in parallel and be controlled independently, in order to regulate the temperature of different modules of the battery or to control different batteries when multiple batteries are present.

[0242] The system for managing battery 410 can be combined with battery 402 to measure the electrical parameters (especially voltage) and temperature (by means of a temperature sensor) of each module, and to control the modules and the main circuit (and optionally the secondary circuit) and, in particular, their pumps, to ensure that the electrical parameters and temperature under consideration are within the desired range.

[0243] A specific example of a thermal control system, including a primary circuit and a secondary circuit, will now be described in more detail.

[0244] refer to Figure 2 An example of a battery assembly according to the invention (particularly applicable to vehicles) includes a thermal regulation system 1 comprising a main circuit 2 containing the aforementioned heat transfer composition and a secondary circuit 3 containing an additional heat transfer composition, the two circuits being thermally connected via at least one heat exchanger 4. The heat transfer composition in the main circuit 2 is configured to move by a pump 7 or by natural convection. The additional heat transfer composition in the secondary circuit 3 is moved by a pump 8. The secondary circuit 3 includes an expansion valve 9 such that evaporation of the additional heat transfer composition in the heat exchanger 4 is ensured to cool the heat transfer composition in the main circuit 2.

[0245] At least one battery module 10 (as described above) is fluidly incorporated into the main circuit 2. A heating element 11 may be combined with or incorporated into the battery module 10.

[0246] When the circuit is equipped with a pump, tank 21 may optionally be located in the main circuit 2 to receive excess heat transfer composition in liquid form.

[0247] In battery cooling mode, pump 7 draws the heat transfer composition from tank 21 and delivers it to battery module 10. The heat transfer composition is in a liquid state at the inlet of battery module 10. It reaches its saturation temperature and partially evaporates as it passes through battery module 10 and absorbs heat dissipated through the cell. It leaves battery module 10 in a two-phase liquid-vapor state. Therefore, battery module 10 acts as an evaporator relative to the main circuit.

[0248] The two-phase heat transfer composition then passes through heat exchanger 4. Another heat transfer composition expands in expansion valve 9 and then evaporates completely or partially in heat exchanger 4. The heat transfer composition condenses, transferring heat to the other heat transfer composition. The liquid form of the heat transfer composition then returns to tank 21.

[0249] Secondary circuit 3 can be the vehicle's air conditioning circuit (compressor not shown in the figure).

[0250] refer to Figure 3 and Figure 4 An example of a battery assembly according to the invention (particularly applicable to vehicles) includes a thermal regulation system 1, which comprises a main circuit 2 as described above and a secondary circuit 3 capable of operating as a reversible heat pump. Therefore, the battery module 10 can be cooled and heated by a heat transfer composition. The secondary circuit has two operating modes: a cooling mode and a heating mode. The cooling mode... Figure 3 As shown in the diagram, the heating mode is... Figure 4 As shown in the image.

[0251] The secondary loop 3 includes an HVAC module 16 (heating, ventilation, and air conditioning) that provides thermal conditioning of the air in the passenger cabin. It includes a condenser 17 and an evaporator 18. The condenser 17 is used to heat the air in the passenger cabin, while the evaporator 18 is used to cool the air in the passenger cabin.

[0252] The secondary loop 3 further includes a control valve 19, a shut-off valve 24, a tank 37, and an external heat exchanger 20. An expansion valve 9 is located downstream of the external heat exchanger 20, and a calibration orifice 25 with a shut-off function is located upstream of the evaporator 18. The expansion valve 9, shut-off valve 24, and calibration orifice 25 may be electrically controlled. The control valve 19 may be a reversible valve and / or a four-way valve capable of changing the circulation direction of another heat transfer composition.

[0253] In cooling mode, control valve 19 is in the first position, causing external heat exchanger 20 to function as a condenser, while heat exchanger 4 and evaporator 18 function as evaporators. In this mode, shut-off valve 24 and calibration orifice 25 are open. The additional heat transfer composition in tank 37 is in a two-phase state, and pump 8 directs it to external heat exchanger 20. The additional heat transfer composition condenses in the latter and is directed to heat exchanger 4 and evaporator 18. In both cases, it evaporates at least partially and returns to tank 37.

[0254] In heating mode, control valve 19 is in the second position, causing external heat exchanger 20 to function as an evaporator, while heat exchanger 4 and condenser 17 function as condensers. In this mode, shut-off valve 24 and calibration orifice 25 are closed. The remaining 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. It is then directed to heat exchanger 4, where it continues to condense. Finally, it passes through external heat exchanger 20, which functions as an evaporator.

[0255] Optionally, a third circuit 12 may be provided and operate in heating mode. The third circuit 12 allows for the collection of heat dissipated by the vehicle's engine 26 and / or electrical components 22. It may include a pump and a radiator 28. A bypass equipped with a shut-off valve 29 allows bypassing the radiator 28. The third circuit 12 is thermally connected to the secondary circuit 3 via a second heat exchanger 13. The third circuit may, for example, include a fluid such as a mixture of water and ethylene glycol. In heating mode, an additional heat transfer composition at the outlet of the heat exchanger 4 is distributed in the external heat exchanger 20 and the second heat exchanger 13, both of which function as evaporators. Therefore, it absorbs the heat dissipated by the fluid in the third circuit 12.

[0256] The secondary circuit 3 may include two check valves 23 (in parallel with the branch including the external heat exchanger 20) on the branch including the second heat exchanger 13, and an expansion valve 9 upstream of the second heat exchanger 13.

[0257] Temperature regulation

[0258] This invention relates to the use of the heat transfer composition according to the invention for cooling a battery. However, the composition can also be used at other times to heat the battery and maintain it in a predominantly liquid form. Heating and cooling can be alternated as needed (external temperature, battery temperature, battery operating mode). Heating the battery is particularly useful when starting a vehicle when the external temperature is cold (e.g., below 10°C, or below 0°C, or below -10°C, or below -20°C).

[0259] Heating can also be achieved, at least partially, and in fact, entirely, by means of an auxiliary heating element, such as a resistor. The auxiliary heating element can be fitted into the battery.

[0260] Therefore, the heat transfer composition according to the invention can be specifically used for uniform cooling of the battery, while other devices such as resistors are used for heating the battery.

[0261] Alternatively, a heating element associated with the main circuit can be provided, particularly upstream of the battery. In this case, the heating element readily heats the heat transfer composition, which in turn heats the battery.

[0262] The term "battery temperature" should be understood to generally refer to the temperature of the outer wall of one or more of its electrochemical cell units.

[0263] The temperature of the battery can be measured using a temperature sensor. If multiple temperature sensors are present at the battery, the battery temperature can be considered as the average of the measured temperatures. This invention makes it possible to significantly reduce the difference between temperatures measured at different points on the battery.

[0264] Temperature regulation can be performed while the vehicle's battery is charging. Alternatively, it can be performed while the battery is discharging, particularly when the vehicle's engine is running. In particular, this prevents the battery temperature from becoming excessively high due to external temperatures and / or due to the battery's overheating characteristics during operation.

[0265] In particular, the battery can be charged quickly. Therefore, during the full charging process (starting from the moment the battery is fully discharged) in a time period of less than or equal to 30 minutes, and preferably less than or equal to 15 minutes, using the composition according to the invention allows the battery temperature to be maintained within an optimal temperature range with a uniform distribution. This is advantageous because during fast charging, the battery tends to heat up rapidly and reach high temperatures, particularly with hot spots, which can degrade battery operation and performance quality and reduce its lifespan.

[0266] In some implementations, battery cooling is continuous over a period of time.

[0267] In some implementations, cooling and optional heating keep the battery temperature within an optimal range, particularly when the vehicle is running (engine started) and especially when the vehicle is moving. This is because if the battery temperature is too low, its performance is prone to significant degradation.

[0268] In some implementations, the temperature of the vehicle's battery can therefore be maintained between a minimum temperature t1 and a maximum temperature t2.

[0269] In some embodiments, the minimum temperature t1 is greater than or equal to 10°C and the maximum temperature t2 is less than or equal to 80°C, preferably the minimum temperature t1 is greater than or equal to 15°C and the maximum temperature t2 is less than or equal to 70°C, and more preferably the minimum temperature t1 is greater than or equal to 16°C and the maximum temperature t2 is less than or equal to 50°C. For example, t1 may be equal to 20°C (in fact, even greater than 20°C), and t2 may be equal to 40°C (in fact, even less than 40°C).

[0270] Advantageously, a feedback loop exists to modify the facility's operating parameters based on the measured battery temperature in order to ensure that the desired temperature is maintained.

[0271] During the duration during which the vehicle's battery temperature is maintained between the minimum temperature t1 and the maximum temperature t2, the external temperature may specifically be -60 to -50°C; or -50 to -40°C; or -40 to -30°C; or -30 to -20°C; or -20 to -10°C; or -10 to 0°C; or 0 to 10°C; or 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.

[0272] The term "external temperature" is understood to refer to the ambient temperature outside the vehicle before and during the period when the vehicle's battery temperature is maintained between the minimum temperature t1 and the maximum temperature t2.

[0273] The present invention also relates to the use of the above-described heat transfer composition for preventing, delaying, or limiting the consequences of battery runaway after a fault (e.g., a short circuit). Runaway is characterized by an uncontrolled rise in temperature, accompanied by the rapid generation of gases, primarily due to the decomposition of the electrolyte, leading to the formation of CO, CO2, HF, and flammable substances (e.g., H2, CH4, C2H4, C2H6, C2H5F) at typical temperatures of 150 to 200°C. The content of flammable gases in the ejected gases can reach at least 30 mol%.

[0274] Therefore, in the event of a malfunction, the above-described heat transfer composition can be used to maintain the battery temperature at less than 150°C, preferably less than 140°C, more preferably less than 140°C, and even more preferably less than 130°C.

[0275] The aforementioned heat transfer composition can also be used to reduce or suppress the flammability of the injected gas mixture in the event of battery runaway. Specifically, it can be used to ensure that the content of flammable gases in the injected gas mixture remains relatively low. It can be used to ensure that the refrigerant content in the injected gas mixture is greater than or equal to 30 mol%, preferably greater than or equal to 40 mol%, or greater than or equal to 50 mol%, or greater than or equal to 60 mol%, or greater than or equal to 70 mol%; in this embodiment, the refrigerant is selected to be non-flammable, i.e., Class A1 in ASHRAE Standard 34; preferably, the refrigerant comprises or consists of HCFO-1233zdE.

[0276] Example

[0277] Example 1 - Miscibility and Dielectric Properties

[0278] By using HCFO-1233zdE as a refrigerant in a mixture of benzyltoluene and dibenzyltoluene (produced by Arkema under the name...) The composition was prepared by combining the two products (C101 sales). It was first confirmed that the two products were miscible in all proportions.

[0279] Oil is added to a 0.2L autoclave by weighing. The autoclave is equipped with a magnetic stirrer and a jacket, and the heat exchange fluid circulates in the jacket to make the temperature in the gas and liquid phases uniform.

[0280] The autoclave was then cooled to -10°C, at which point a vacuum was drawn.

[0281] The HCFO-1233zdE contained in the cylinder is transferred as a liquid phase in a closed-loop mode by weighing.

[0282] Calculate the minimum volume of liquid to be added so that the composition of the liquid phase does not change as a function of temperature.

[0283] The final mixture is brought to the desired temperature with stirring to homogenize it. The stirring is then turned off until the mixture reaches equilibrium. Temperature and pressure are recorded at equilibrium.

[0284] Figure 5 The effect of refrigerant content on the liquid saturation temperature of the composition at a saturated vapor pressure of 1 bar is shown. More specifically, it was observed that adding refrigerant (even at a low content) to the composition significantly reduced the liquid saturation temperature of the composition relative to a composition containing 100% oil, which increased the cooling capacity of the battery.

[0285] Under the conditions presented below, by mixing 69.2g of HCFO-1233zdE and 100.5g of [unclear - possibly a product name] from Arkema... The composition was prepared using C101.

[0286] [Table 1]

[0287] 20 0.71 Miscible 60 2.5 Miscible

[0288] Under the conditions presented below, by mixing 35 wt% HCFO-1233zdE and 65 wt% from Arkema C101 was used to prepare another composition.

[0289] Breakdown voltage is measured according to standard IEC 60159:1995.

[0290] [Table 2]

[0291]

[0292] Example 2 - Viscosity

[0293] Viscosity measurements were performed in a high-pressure autoclave reactor (with a capacity of 0.2 L) with a jacket in which a heat exchange fluid circulates. The fluid was introduced into the reactor... C101 oil. The reactor was cooled to -10°C and magnetically stirred. Then HCFO-1233zdE was introduced via differential pressure. The reactor was then brought to the measured temperature.

[0294] Viscosity measurements were then performed using a Sofraser MIVI 9601 vibrating rod viscometer. The camera allowed for confirmation of the miscibility of the oil and refrigerant under measurement conditions and verification of the viscometer rod immersion before measurement.

[0295] [Table 3]

[0296] T(℃) 20 20 0 0 Dynamic viscosity (cP) 6.0 3.9 12 6.5

[0297] For comparison, the viscosity of the oil (0% HCFO-1233zdE) was measured at 20°C according to standard ISO 3104. The obtained value was 6.5 cP.

[0298] Example 3 - Flammability

[0299] For those containing 90% by weight A composition of C101 oil and 10% by weight of HCFO-1233zdE, and a composition containing 100% by weight of... Flash point measurements were performed on a comparative composition of C101 oil.

[0300] The mixture is prepared at low temperature and atmospheric pressure. It is homogeneous and liquid at ambient temperature and atmospheric pressure.

[0301] Flash point measurements are performed according to standard ISO 3679 or ISO 3680, "Flash / no-flash type flash point test - rapid equilibrium closed cup method". The standardized test is conducted with the filling port open to allow for breathing into the atmosphere, and then the pan is closed.

[0302] Depending on the circumstances, the test can be adjusted by blocking the filling port to simulate even more restrictive devices during temperature equilibration (2 minutes under standardized conditions). In this case, the test is conducted with the capped port closed.

[0303] The temperature range explored is up to 300°C.

[0304] [Table 4]

[0305] Flash point 138℃ Not detected

[0306] Example 4 - Heat Transfer Coefficient (Two-Phase Immersion)

[0307] To measure the heat transfer coefficient, a test apparatus placed in a thermal conditioning chamber is used to measure the fluid's performance qualities by varying the ambient temperature. The test apparatus includes a container equipped with a heating element and a condenser. The condenser is located at the top of the container and is cooled by an ice-cold water circuit. The heating element is a cylindrical resistor with a diameter of 15 mm and a height of 80 mm encased in a copper sheath, which is vertically immersed in a cylinder filled with a saturated liquid to heat it. It can deliver up to 15 W / cm². 2 Eight temperature sensors are placed on the copper sheath to measure the surface temperature.

[0308] Two different mixtures of oil and HCFO-1233zdE were tested, and the properties of the oil, particularly its viscosity, were compared with those of... Those similar to C101 oil, and the properties of said oil, especially thermal (thermal conductivity greater than 0.05 W / (m)). 2 The K) and dielectric properties meet the specifications of this application. First, HCFO-1233zdE is introduced, while avoiding the introduction of any moisture or air contamination. The oil is added by gravity using a graduated cylinder. Miscibility and homogeneity are checked by sampling.

[0309] Set the cooling water temperature (10°C at the condenser) and flow rate to desired values. Set the ambient temperature to 26°C. Increase the heat power from 0 to 90W in 5W increments, then decrease it again to detect hysteresis. Measure the average heat transfer coefficient during the temperature rise: H = F / (T w -T sat ), where F is the heat flux density, Tw Let T be the temperature of the wall, and T sat The liquid saturation temperature of the measured composition.

[0310] [Table 5]

[0311] <![CDATA[F(W / cm 2 )]]> 0.5 0.5 1.5 1.5 2.5 <![CDATA[H(W / (m 2 .K))]]> 197 573 441 973 1548

[0312] Example 5 - Preventing Loss of Control

[0313] The tests were conducted on a compact assembly of eight energy storage cells housed in a sealed housing filled with either fluid A (pure HCFO-1233zdE) or fluid B (60 wt% HCFO-1233zdE + 40 wt% aliphatic hydrocarbon dielectric oil). The housing was equipped with valves calibrated for pressures greater than the vapor pressure of the fluids at 50°C.

[0314] The test was equipped with thermocouples to monitor the temperature of the cell walls and fluids. After washing to remove acidic products, the injected gas was analyzed by gas chromatography.

[0315] The characteristics of a single-cell battery are as follows:

[0316] Model: Samsung INR 18650 35E.

[0317] - Electrical architecture: 1s8p.

[0318] - Capacity: 3.5Ah.

[0319] -Chemical composition: LiNiCoMnO2.

[0320] - Voltage: Minimum 2.5V, nominal 3.6V, maximum 4.2V.

[0321] At time t=0, a short circuit is created by pinning a pin to one of the cells that has been charged to its maximum. The associated cell then undergoes thermal runaway, which is reflected by the increase in pressure and the opening of a valve in the casing.

[0322] In the case of fluid A, the valve calibration pressure is 4 bar absolute pressure. The HCFO-1233zd content in the injected gas is greater than 60 mol%.

[0323] Gas analysis did not show any degradation of HCFO-1233zd.

[0324] The runaway will not spread to other cell units that remain intact.

[0325] In the case of fluid B, the valve's calibration pressure is 3 bar absolute pressure. The HCFO-1233zd content in the injected gas is greater than 50 mol%. The runaway did not propagate to other cell units that remain intact. Gas analysis showed no degradation of HCFO-1233zd, nor any reaction with oil.

Claims

1. Use of a heat transfer composition for cooling a battery, the heat transfer composition comprising 20% ​​to less than 100% by weight of a refrigerant and greater than 0% to 80% by weight of a dielectric fluid, the battery comprising an energy storage cell immersed in the heat transfer composition, and the heat transfer composition undergoing evaporation upon contact with the energy storage cell, wherein the refrigerant is 1-chloro-3,3,3-trifluoropropylene, and the dielectric fluid is an aromatic hydrocarbon selected from alkylbenzenes, alkyldiphenyl ethane, alkylnaphthalenes, methylpolyarylmethane, and combinations thereof.

2. The use as described in claim 1, wherein the heat transfer composition is circulated in a heat transfer loop.

3. The use as described in claim 2, wherein the battery comprises one or more modules, each module comprising a housing in which an energy storage unit battery is disposed, the housing forming part of the heat transfer circuit.

4. The use as described in claim 2 or 3, wherein the heat transfer circuit is thermally coupled to a secondary circuit containing an additional transfer composition.

5. The use as described in claim 4, wherein the secondary circuit is a vehicle air conditioning circuit; and / or a reversible heat pump circuit.

6. The use as described in any one of claims 1 to 3, wherein the refrigerant is 1-chloro-3,3,3-trifluoropropylene in the E form.

7. The use as described in any one of claims 1 to 3, wherein the battery is a battery for an electric or hybrid vehicle.

8. The use as described in claim 7, wherein the battery is a battery for an electric or hybrid vehicle.

9. The use as described in claim 7, which is carried out during the charging of the vehicle's battery.

10. The use as claimed in claim 9, wherein the vehicle's battery is fully charged within a period of less than or equal to 30 minutes from the start of its complete discharge.

11. The use as claimed in claim 9, wherein the vehicle's battery is fully charged within a period of less than or equal to 15 minutes from the start of its complete discharge.

12. A battery assembly comprising one or more modules, each module including a housing in which an energy storage cell battery is disposed, the housing being immersed in a heat transfer composition comprising 20% ​​to less than 100% by weight of a refrigerant and greater 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, wherein the refrigerant is 1-chloro-3,3,3-trifluoropropylene and the dielectric fluid is an aromatic hydrocarbon selected from alkylbenzenes, alkyldiphenyl ethane, alkylnaphthalenes, methylpolyarylmethanes, and combinations thereof.

13. The battery assembly of claim 12, wherein the battery assembly is a battery assembly for an electric or hybrid vehicle.

14. The battery assembly of claim 12, comprising a heat transfer circuit in which a heat transfer composition circulates, and the housing of the module is incorporated into the heat transfer circuit.

15. The battery assembly of claim 14, wherein the heat transfer circuit includes a pump; and / or wherein the heat transfer circuit includes a heat exchanger to enable the heat transfer composition to exchange heat with ambient air or with a heat transfer composition in a secondary circuit.

16. The battery assembly of any one of claims 12 to 15, wherein the refrigerant is 1-chloro-3,3,3-trifluoropropylene in the E form.

17. A method for regulating the battery temperature of a battery assembly as described in any one of claims 12 to 16, comprising cooling an energy storage cell battery by means of partial evaporation of a heat transfer composition via the heat transfer composition.

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