EP4046223A1

EP4046223A1 - Method for controlling the temperature of a battery comprising a lithium salt

Info

Publication number: EP4046223A1
Application number: EP20792471.3A
Authority: EP
Inventors: Gregory Schmidt
Original assignee: Arkema France SA
Current assignee: Arkema France SA
Priority date: 2019-10-15
Filing date: 2020-09-29
Publication date: 2022-08-24
Also published as: FR3102010B1; CN114788062A; WO2021074498A1; JP2022552968A; US20240128547A1; FR3102010A1

Abstract

The invention relates to a method for controlling the temperature of a battery in an electric or hybrid motor vehicle by means of a system comprising a vapor compression circuit in which a first heat transfer composition flows, and a secondary circuit in which a second heat transfer composition flows, said method involving: - heat exchange between the battery and the second heat transfer composition; - heat exchange between the second heat transfer composition and the first heat transfer composition; wherein the battery comprises at least one electrochemical cell having a negative electrode, a positive electrode and an electrolyte comprising a lithium salt composition, said lithium salt composition comprising: - at least 99.75%, preferably at least 99.85%, advantageously at least 99.95%, even more advantageously 99.99% by weight of a lithium salt of bis(fluorosulfonyl)imide; - chlorides Cl- at a mass content strictly less than 20 ppm; wherein the total mass content of chlorides Cl-, fluorides F- and sulfates SO42- is preferably less than or equal to 150 ppm. The invention also relates to a system for carrying out said method.

Description

DESCRIPTION

TITLE: Process for regulating the temperature of a battery comprising a lithium salt

Field of the invention

The present invention relates to a method for regulating the temperature of a battery of a motor vehicle, as well as to an installation suitable for implementing this method.

Technical background

The batteries of electric or hybrid vehicles give maximum performance under specific conditions of use and especially in a very specific temperature range. Maximum efficiency means high instantaneous available power, high total available capacity, as well as increased battery life. Thus, the maximum efficiency of a battery not only allows better performance and range of vehicles but also lower energy consumption of vehicles per km. In addition, when operating the electric or hybrid vehicle, the temperature of the battery increases and must always be kept at a temperature below 60 ° C, preferably at a temperature below 40 ° C to avoid premature aging, see destruction drums. At temperatures below 15 ° C, the battery charge decreases due to increased internal resistance. Therefore, while operating a vehicle, the temperature of the battery should be kept between about 15 and 40 ° C. Operation of the battery life below 0 ° C damages the battery cells and consequently results in damage to the battery cells. therefore a significant reduction in the life of the battery unit, so that such a condition should be avoided.

In motor vehicles, the heat engine has a circuit for circulating a heat transfer fluid which is used for cooling the engine and also for heating the passenger compartment. To this end, the circuit comprises in particular a pump and an air heater in which circulates an air flow which recovers the heat stored by the heat transfer fluid in order to heat the passenger compartment.

Furthermore, a cooling system comprises an evaporator, a compressor, a condenser, an expansion valve and a fluid capable of change of state (liquid / gas) commonly referred to as refrigerant or heat transfer fluid. The compressor, directly driven by the vehicle engine using a belt and pulley, compresses the refrigerant, delivering it under high pressure and high temperature to the condenser. The condenser, thanks to forced ventilation, causes condensation of the gas which arrives in the gaseous state at high pressure and high temperature. The condenser liquefies the gas by lowering the temperature of the air passing through it. The evaporator is a heat exchanger which takes calories from the air which will be blown into the passenger compartment or from the vehicle battery. The regulator makes it possible to regulate the gas inlet flow in the loop via a modification of the passage section depending on the temperature and the pressure at the evaporator. Thus, the hot air coming from the outside or the battery of the vehicle cools in contact with the evaporator.

The refrigerant traditionally used in automotive air conditioning is 1, 1, 1, 2-tetrafluoroethane (HFC-134a).

However, a large number of HFC fluids, including HFC-134a, can contribute negatively to the greenhouse effect. This contribution is quantified by a numerical parameter, the GWP (Global Warming Potential).

Another refrigerant now used in heat transfer applications is 2,3,3,3-tetrafluoropropene (HFO-1234yf). However, even though HFO-1234yf is a low GWP fluid, it is considered a flammable fluid.

EP 3499634 relates to a thermal management system for a vehicle battery with at least one battery unit.

WO 2017/143018 relates to refrigerant systems for conditioning air and / or articles located in a dwelling occupied by humans or other animals.

Document DE 202014010264 relates to a vehicle comprising at least a first compression refrigeration device designed to cool an internal space of the vehicle and comprising a circulating refrigerant, characterized in that the refrigerant is a substance from the family of fluoroketones and / or ( hydro) fluoroolefins and / or (hydro) fluorochlorolefins.

There is a need to provide an efficient and safe method of regulating the temperature of a battery of a motor vehicle, while limiting or reducing the amount of flammable products in the vehicle or the environment. proximity of these to the hottest parts of the vehicle, while preserving battery life as much as possible.

Summary of the invention

The invention relates firstly to a method of regulating the temperature of a battery of an electric or hybrid motor vehicle, by means of a system comprising a vapor compression circuit in which circulates a first heat transfer composition. and a secondary circuit in which circulates a second heat transfer composition, the method comprising:

- the heat exchange between the battery and the second heat transfer composition;

- the heat exchange between the second heat transfer composition and the first heat transfer composition; the battery comprising at least one electrochemical cell comprising a negative electrode, a positive electrode and an electrolyte comprising a lithium salt composition, said lithium salt composition comprising:

- at least 99.75%, preferably at least 99.85%, advantageously at least 99.95%, even more advantageously 99.99% by mass of a lithium salt of bis (fluorosulfonyl) imide;

- Cl chlorides in a mass content strictly less than

20 ppm; in which the total mass content of CI chlorides, F fluorides and SC sulphates> 4 ² is preferably less than or equal to 150 ppm.

In embodiments, the first heat transfer composition comprises 2,3,3,3-tetrafluoropropene.

In embodiments, the first heat transfer composition comprises one or more heat transfer compounds other than 2,3,3,3-tetrafluoropropene, these compounds preferably being selected from difluoromethane, pentafluoroethane, 1 , 1, 2,2-tetrafluoroethane, 1, 1, 1, 2-tetrafluoroethane, 1, 1 -difluoroethane, fluoroethane, 1, 1, 1, 2,3,3,3-heptafluoropropane, 1, 1, 1 -trifluoropropane and mixtures thereof, and more preferably this compound being difluoromethane.

In embodiments, 2,3,3,3-tetrafluoropropene is present at a content of about 78.5% by weight in the first composition and difluoromethane is present at a content of about 21.5% by weight. weight in the first composition. In embodiments, the second heat transfer composition comprises one or more heat transfer compounds having a boiling point of 0 to 40 ° C, preferably selected from hydrochlorofluoroolefins, hydrofluoroolefins, and combinations thereof. -this ; more preferably chosen from 1-chloro-3,3,3-trifluoropropene, preferably in E form; 1-chloro-2,3,3,3-tetrafluoropropene, preferably in Z form, and 1, 1, 1, 4,4,4-hexafluorobut-2-ene in E and / or Z form.

In embodiments, the second heat transfer composition is at a substantially uniform pressure in the secondary circuit, said pressure preferably being equal to the saturation pressure of the second composition.

In some embodiments, the battery is maintained at a temperature between a minimum temperature ti and a maximum temperature t2.

In some embodiments, the minimum temperature ti is greater than or equal to 0 ° C and the maximum temperature t2 is less than or equal to 60 ° C, more preferably the minimum temperature ti is greater than or equal to 15 ° C and the temperature maximum fe is less than or equal to 40 ° C, and more preferably the minimum temperature ti is greater than or equal to 16 ° C and the maximum temperature fe is less than or equal to 28 ° C.

In some embodiments, the method is implemented during the charging of 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.

In some embodiments, the second heat transfer composition is in direct contact with the vehicle battery.

The invention also relates to an installation for regulating the temperature of a battery of an electric or hybrid motor vehicle, comprising:

a vapor compression circuit in which circulates a first heat transfer composition; and

a secondary circuit in which circulates a second heat transfer composition; the vapor compression circuit being coupled with the secondary circuit by an intermediate heat exchanger, so as to allow the exchange of heat between the first heat transfer composition and the second heat transfer composition; and the installation including an additional heat exchanger configured to exchange heat between the battery and the second heat transfer composition; the battery comprising at least one electrochemical cell comprising a negative electrode, a positive electrode and an electrolyte comprising a lithium salt composition, said lithium salt composition comprising:

- Cl chlorides in a mass content strictly less than

20 ppm; in which the total mass content of Cl chlorides, F fluorides and SC sulphates> 4 ² is preferably less than or equal to 150 ppm.

In some embodiments, the secondary circuit does not include a compressor.

In some embodiments, the circulation of the second heat transfer composition in the secondary circuit is effected by means of a pump, or by gravity, or by capillarity.

In embodiments, the installation is further suitable for air conditioning the vehicle interior, and / or heating the vehicle interior, and / or cooling electronic components of the vehicle, and / or heating of electronic components of the vehicle.

In embodiments, 2,3,3,3-tetrafluoropropene is present at a content of about 78.5% by weight in the first composition and difluoromethane is present at a content of about 21.5% by weight. weight in the first composition.

The present invention makes it possible to meet the need expressed above. It more particularly provides an efficient and secure method of regulating the temperature of a battery of a motor vehicle. It makes it possible, if necessary, to limit or reduce the quantity of flammable products in the vehicle or their proximity to the hottest parts of the vehicle. It also helps preserve battery life.

This is accomplished through the coupled use of two heat transfer compositions, one circulating in a vapor compression circuit, and the other circulating in a secondary circuit, the heat transfer composition in the secondary circuit performing. the heat transfers required with the vehicle battery. Preferably, the heat transfer composition in the secondary circuit does not contain flammable heat transfer compound; or this composition is non-flammable. More particularly, when HFO-1234yf is used as a heat transfer fluid in the vapor compression circuit, the use of the secondary circuit makes it possible to limit the extent of the vapor compression circuit and to reduce the quantity of HFO- 1234yf used and / or to prevent the FIFO-1234yf from being near the hottest parts of the vehicle, in particular the vehicle battery, thereby reducing the risk of leakage and fire. In addition, the use of a secondary circuit facilitates thermal management of the vehicle. More particularly, and if we take electric cars as an example, many heat sources (battery, electrical and electronic circuit, engine) as well as many heating and / or cooling needs (battery, passenger compartment) exist on different levels of heat. temperatures. The use of a secondary circuit comprising a heat transfer fluid facilitates the thermal management of this equipment compared to other technologies.

In some embodiments, the use of the secondary circuit also allows a reduction in energy consumption thanks to low pumping power, compared to the use of a single-phase heat transfer fluid.

In some embodiments, the use of the secondary circuit comprising the second heat transfer composition allows weight reduction of the vehicle, by avoiding the use of solid phase change materials to effect heat exchange.

In some embodiments, the second heat transfer composition not containing flammable heat transfer compounds, or being at the very least non-flammable, can also serve as an extinguishing agent in the event of overheating of the battery of the heater. vehicle.

Furthermore, it has been observed that a battery containing an electrolyte as described above has an improved lifespan, and that corrosion of its constituents is reduced or even eliminated; and all the more so since its temperature is regulated by the two-circuit installation described above.

The electrolyte of the invention has a higher ionic conductivity and therefore the battery tends to heat up less. In conjunction with the thermal regulation system, the battery temperature is particularly well controlled.

In addition, the reduction or elimination of corrosion helps prevent short circuits and possibly work in immersion of the battery.

Brief description of the figures

Figure 1 schematically shows an embodiment of an installation according to the invention.

detailed description

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

The invention relates to a heat transfer method for regulating the temperature, namely for cooling and / or for heating a battery of a motor vehicle, implemented by means of a heat transfer installation. heat. The facility contains a first and a second heat transfer composition, each heat transfer composition comprising a heat transfer fluid which includes one or more heat transfer compounds.

By "heat transfer compound" is meant a compound capable of absorbing heat by evaporating and rejecting heat by condensing, in the application in question.

In the context of the invention, "HFO-1234yf" refers to 2,3,3,3-tetrafluoropropene, "HCFO-1233zd" refers to

1 -chloro-3,3,3-trifluoropropene, "HCFO-1224yd" refers to 1 -chloro-2,3,3,3-tetrafluoropropene, and "HFO-1336mzz" refers to

1, 1, 1, 4,4,4-hexafluorobut-2-ene.

Vehicle battery

The motor vehicle is an electric or hybrid vehicle. It comprises at least one electric motor, and where appropriate a heat engine. It thus comprises an electronic circuit and a traction battery, referred to more simply as a battery in the following. The battery comprises at least one electrochemical cell, and preferably a plurality of electrochemical cells. Each electrochemical cell has a negative electrode, a positive electrode and an electrolyte interposed between the negative electrode and the positive electrode.

Each electrochemical cell can also include a separator, in which the electrolyte is impregnated.

The electrochemical cells can be assembled in series and / or in parallel in the battery.

By “negative electrode” is meant the electrode which acts as an anode when the battery delivers current (that is to say when it is in the process of discharging) and which acts as a cathode when the battery is discharged. is charging. The negative electrode typically comprises an electrochemically active material, optionally an electronically conductive material, and optionally a binder.

By "positive electrode" is meant the electrode which acts as a cathode, when the battery delivers current (that is to say when it is in the process of discharging) and which acts as anode when the battery is discharged. is charging. The positive electrode typically comprises an electrochemically active material, optionally an electronically conductive material, and optionally a binder.

By "electrochemically active material" is meant a material capable of reversibly inserting ions.

The term “electronically conductive material” is understood to mean a material capable of conducting electrons.

The negative electrode of the electrochemical cell can in particular comprise, as electrochemically active material, graphite, lithium, a lithium alloy, a lithium titanate of the LLTi50i2 type or titanium oxide PO2, silicon or an alloy of lithium and silicon, tin oxide, an intermetallic compound of lithium, or a mixture thereof.

When the negative electrode comprises lithium, it may be in the form of a metallic lithium film or an alloy comprising lithium. Among the lithium-based alloys that may be used, mention may be made, for example, of lithium-aluminum alloys, lithium-silica alloys, lithium-tin alloys, Li-Zn, LÎ3BÎ, LhCd and U3SB. An example of a negative electrode may include a live lithium film prepared by laminating, between rolls, a lithium strip.

The positive electrode comprises an electrochemically active material of the oxide type. It is a lithium-nickel-manganese-cobalt composite oxide high nickel content (LiNi _x Mn _y Coz02 with x + y + z = 1, abbreviated NMC, with x> y and x> z), or a lithium-nickel-cobalt-aluminum composite oxide at high rate nickel (LiNixCoyAlz 'with x' + y '+ z' = 1, abbreviated NCA, with x '>y' and x '> z).

Particular examples of these oxides are NMC532 (LiNio, 5Mno, 3Coo, 202), NMC622 (LiNio, 6Mno, 2Coo, 202) and NMC811 (LiNio, 8Mno, iCoo, i02).

Mixtures of these oxides can be used. The oxide material described above can optionally be combined with another oxide such as for example: manganese dioxide (MnC> 2), iron oxide, copper oxide, nickel oxide, lithium-manganese composite oxides (for example LixMn204 or LixMnC), lithium-nickel composition oxides (for example Li _x NiC> 2), lithium-cobalt composition oxides (for example Li _x CoC> 2), lithium composite oxides -nickel-cobalt (for example LiNii-yCoyC> 2), composite oxides of lithium and transition metal, composite lithium-manganese-nickel oxides of spinel structure (for example Li _x Mn2-yNiy04), oxides of vanadium, oxides NMC and NCA which are not high nickel content, and mixtures thereof.

Preferably, the NMC or NCA oxide with a high nickel content represents at least 50% by weight, preferably at least 75% by weight, more preferably at least 90% by weight, and more preferably still essentially all, of the oxide material present in the positive electrode as an electrochemically active material.

The material of each electrode can also comprise, in addition to the electrochemically active material, an electronically conductive material such as a carbon source, including, for example, carbon black, Ketjen® carbon, Shawinigan carbon, graphite, graphene, carbon nanotubes, carbon fibers (eg, carbon fibers formed in the gas phase or VGCF), non-powdery carbon obtained by carbonization of an organic precursor, or a combination of two or more thereof. Other additives may also be present in the material of the positive electrode, such as lithium salts or inorganic particles such as ceramic or glass, or other compatible active materials (for example, sulfur).

The material of each electrode can also include a binder. Non-limiting examples of binders include linear, branched and / or crosslinked polyether polymeric binders (eg, polymers based on poly (ethylene oxide) (PEO), or poly (propylene oxide) (PPO) or a mixture of the two (or an EO / PO copolymer), and optionally comprising crosslinkable units), water-soluble binders (such as SBR (styrene-butadiene rubber), NBR (acrylonitrilebutadiene rubber), HNBR (hydrogenated NBR), CHR (epichlorohydrin rubber), ACM (acrylate rubber)), or fluoropolymer type binders (such as PVDF (polyvinylidene fluoride), PTFE (polytetrafluoroethylene), and their combinations. Certain binders, such as those soluble in water, can also include an additive such as CMC (carboxymethylcellulose).

The separator can be a porous polymer film. By way of non-limiting example, the separator can be made of a porous polyolefin film such as ethylene homopolymers, propylene homopolymers, ethylene / butene copolymers, ethylene / hexene copolymers, ethylene / methacrylate copolymers, or multilayer structures of the above polymers.

Electrolyte

The electrolyte present in the battery preferably comprises:

- a composition of lithium salt;

- said lithium salt composition being dissolved in a solvent or a mixture of solvents;

- where appropriate with one or more additives.

The solvent (s) can be chosen from the following non-exhaustive list: ethers, esters, ketones, alcohols, nitriles and carbonates.

Among the ethers, mention may be made of linear or cyclic ethers, such as, for example, dimethoxyethane (DME), methyl ethers of oligoethylene glycols of 2 to 5 oxyethylene units, dioxolane, dioxane, dibutyl ether, tetrahydrofuran, and their mixtures.

Among the esters, mention may be made of phosphoric acid esters or sulfite esters. Mention may be made, for example, of methyl formate, methyl acetate, methyl propionate, ethyl acetate, butyl acetate, gamma butyrolactone or mixtures thereof.

Among the ketones, mention may in particular be made of cyclohexanone.

Among the alcohols, there may be mentioned, for example, ethyl alcohol, isopropyl alcohol.

Among the nitriles, mention may be made, for example, of acetonitrile, pyruvonitrile, propionitrile, methoxypropionitrile, dimethylaminopropionitrile, butyronitrile, isobutyronitrile, valeronitrile, pivalonitrile, isovaleronitrile, glutaronitrile, methoxyglutaronitrile, 2-methylglutaronitrile, 3-methylglutaronitrile, adiponitrile and mixtures thereof, malalone, adiponitrile and their mixtures.

Among the carbonates, mention may be made, for example, of cyclic carbonates such as, for example, ethylene carbonate (EC) (CAS: 96-49-1), propylene carbonate (PC) (CAS: 108-32-7) , butylene carbonate (BC) (CAS: 4437-85-8), dimethyl carbonate (DMC) (CAS: 616-38-6), diethyl carbonate (DEC) (CAS: 105-58-8 ), methyl ethyl carbonate (EMC) (CAS: 623-53-0), diphenyl carbonate (CAS 102-09-0), methyl phenyl carbonate (CAS: 13509-27-8), carbonate dipropyl (DPC) (CAS: 623-96-1), methyl propyl carbonate (MPC) (CAS: 1333-41 -1), ethyl propyl carbonate (EPC), vinylene (VC) (CAS: 872-36-6), fluoroethylene carbonate (FEC) (CAS: 114435-02-8), trifluoropropylene carbonate (CAS: 167951 -80-6) or their mixtures.

The additive (s) can be chosen from the group consisting of fluoroethylene carbonate (FEC), vinylene carbonate, 4-vinyl-1, 3-dioxolan-2-one, pyridazine, vinyl pyridazine, quinoline, vinyl quinoline, butadiene, sebaconitrile, alkyldisulfides, fluorotoluene, 1, 4-dimethoxytetrafluorotoluene, t-butylphenol, di-t-butylphenol, tris (pentafluorophenyl) borane, oximes, epoxides aliphatics, halogenated biphenyls, metacrylic acids, allyl ethyl carbonate, vinyl acetate, divinyl adipate, propanesultone, acrylonitrile, 2-vinylpyridine, maleic anhydride, methyl cinnamate, phosphonates, vinyl containing silane compounds, 2-cyanofuran.

According to the invention, the composition of lithium salt conforms to one of the following objects.

Object 1. Composition comprising:

- Cl chlorides in a mass content strictly less than

20 ppm;

the total mass content of CL chlorides, F fluorides and SO4 ² sulphates preferably being less than or equal to 150 ppm. In the context of the invention, the terms “lithium salt of bis (fluorosulfonyl) imide”, “lithium bis (sulfonyl) imide”, “LiFSI”, “LiN (FSC> 2) 2”, are used in an equivalent manner, "Lithium bis (sulfonyl) imide", or "lithium bis (fluorosulfonyl) imide".

The notation ppm or "parts per million" is understood by weight.

Object 2: composition according to object 1, such that [SO4 ² ] + [CI-] + [F-] <120 ppm, preferably [SO4 ² ] + [CI-] + [F-] <100 ppm, advantageously [SO4 ² ] + [CI-] + [F-] <80 ppm, even more advantageously [SO4 ² ] + [CL] + [F j <50 ppm, in particular [SO4 ² ] + [CL] + [F -] <30 ppm, and for example [SO4 ² -] + [CL] + [F-] <20 ppm.

Object 3: composition according to object 1 or 2, comprising a mass content of sulphates less than or equal to 100 ppm, preferably less than or equal to 50 ppm, advantageously less than or equal to 30 ppm, even more advantageously less than or equal to 20 ppm, in particular less than or equal to 10 ppm, relative to the total mass of the composition.

Object 4: composition according to any one of objects 1 to 3, in which the mass content of sulphates is strictly greater than 0 ppm, preferably greater than or equal to 0.1 ppm, relative to the total mass of the composition.

Object 5: composition according to any one of objects 1 to 4, in which the mass content of sulphates ranges from 0.1 ppm to 100 ppm, preferably from 0.1 ppm to 80 ppm, preferably from 0.1 ppm to 50 ppm, advantageously from 0.1 ppm to 20 ppm, even more advantageously from 0.1 ppm to 10 ppm, and in particular from 0.1 ppm to 5 ppm, relative to the total mass of the composition.

Object 6: composition according to any one of objects 1 to 5, in which the mass content of chlorides CL is less than or equal to 18 ppm, preferably less than or equal to 15 ppm, preferably less than or equal to 12 ppm, advantageously less or equal to 10 ppm relative to the total mass of the composition.

Object 7: composition according to any one of objects 1 to 6, in which the mass content of chlorides CL is strictly greater than 0, preferably greater than or equal to 0.1 ppm, preferably greater than or equal to 0.5 ppm, even more preferably greater than or equal to 1 ppm, advantageously greater than or equal to 2 ppm, even more advantageously greater than or equal to 3 ppm, and in particular greater than or equal to 4 ppm relative to the total mass of the composition. Object 8: composition according to any one of objects 1 to 7, in which the mass content of Cl chlorides ranges from 0.1 ppm to less than 20 ppm, preferably from 0.1 ppm to 18 ppm, preferably from 0, 1 ppm to 15 ppm, advantageously from 0.1 ppm to 12 ppm, and in particular from 0.1 ppm to 10 ppm relative to the total mass of the composition.

Object 9: composition according to any one of objects 1 to 8, in which the mass content of fluorides F is greater than or equal to 0.1 ppm, preferably greater than or equal to 0.5 ppm, preferably greater than or equal to 1 ppm, advantageously greater than or equal to 2 ppm, even more advantageously greater than or equal to 3 ppm, and in particular greater than or equal to 4 ppm relative to the total mass of the composition.

Object 10: composition according to any one of objects 1 to 9, in which the fluoride content by mass is less than or equal to 100 ppm, preferably less than or equal to 80 ppm, preferably less than or equal to 60 ppm, advantageously less than or equal to 50 ppm, even more advantageously less than or equal to 30 ppm relative to the total mass of the composition.

Object 11: composition according to any one of objects 1 to 10, in which the mass content of fluorides F in the composition ranges from 0.1 ppm to 100 ppm, preferably from 0.1 ppm to 80 ppm, preferably from 0 , 1 ppm to 60 ppm, advantageously from 0.1 ppm to 50 ppm, and in particular from 0.1 ppm to 30 ppm relative to the total mass of the composition.

Object 12: composition according to any one of objects 1 to 11, comprising less than 200 ppm of K ⁺ , preferably less than 150 ppm, preferably less than 100 ppm, advantageously less than 50 ppm, even more advantageously less than 30 ppm , and in particular less than 10 ppm by mass relative to the total mass of the composition.

Object 13: composition according to any one of objects 1 to 12, comprising strictly more than 0 ppm of K ⁺ , preferably from strictly more than 0 ppm to less than 100 ppm, advantageously from strictly more than 0 ppm to less than 50 ppm , even more advantageously from strictly more than 0 ppm to less than 30 ppm, and in particular from strictly more than 0 ppm to less than 10 ppm by mass relative to the total mass of the composition.

Object 14: composition according to any of the objects 1 to 13, in which:

[S04 ² ] + [CI] + [F] + [K ⁺ ] <150 ppm This means that the sum of the total mass contents of sulphates (SC> 4 ² ), chlorides (Cl), fluorides (F) and potassium ions (K ⁺ ) is less than or equal to 150 ppm, relative to the mass total composition.

Object 15: composition according to any of objects 1 to 14, in which:

[SO4 ² ] + [CI] + [F] + [K ⁺ ] <120 ppm, preferably [SO4 ^{2 '} ] + [Ch] + [F-] + [K ⁺ ] <100 ppm, advantageously [SO4 ^2' ] + [Ch] + [F-] + [K ⁺ ] <80 ppm, even more advantageously [SO4 ^{2 '} ] + [Ch] + [F-] + [K ⁺ ] <50 ppm, in particular [SO4 ^{2 '} ] + [Ch] + [F-] + [K ⁺ ] <30 ppm, and for example [SO4 ^2' ] + [Ch] + [F-] + [K ⁺ ] <20 ppm.

Object 16: composition according to any one of objects 1 to 15, comprising less than 200 ppm of water, preferably less than 150 ppm, preferably less than 100 ppm, advantageously less than 50 ppm, even more advantageously less than 30 ppm , and in particular less than 10 ppm by mass of water relative to the total mass of the composition.

Object 17: composition according to any one of objects 1 to 16, comprising strictly more than 0 ppm of water, preferably from strictly more than 0 ppm to less than 100 ppm, advantageously from strictly more than 0 ppm to less than 50 ppm , even more advantageously from strictly more than 0 ppm to less than 30 ppm, and in particular from strictly more than 0 ppm to less than 10 ppm by mass relative to the total mass of the composition.

In some embodiments, only the composition of one of the above objects is a possible source of the ions mentioned above in the electrolyte (and optionally only the composition of one of the above objects is a source. possible water in the electrolyte). Therefore, the contents given above apply mutatis mutandis to the electrolyte itself.

In other words, advantageously, when the electrolyte contains a composition according to object 1, then the mass content of chloride ions Ch in the electrolyte is strictly less than 20 ppm relative to the LiFSI salt; and the total mass content of Ch chlorides, F fluorides and sulphates S04 ² in the electrolyte is preferably less than or equal to 150 ppm relative to the LiFSI salt. And so on if the electrolyte contains a composition according to one of objects 2 to 17.

The composition according to one of the above objects can be obtained by a process for purifying a lithium salt of bis (fluorosulfonyl) imide in solution in an organic solvent S1, said process possibly comprising the following steps: a) liquid-liquid extraction of said salt from the solution containing the organic solvent S1 and the salt, with deionized water to form an aqueous solution of said bis (fluorosulfonyl) imide salt; a ') optional concentration of said aqueous solution; b) liquid-liquid extraction of the lithium salt of bis (fluorosulfonyl) imide from said aqueous solution (obtained in step a) or step a ')), with an organic solvent S2; c) concentrating the lithium salt of bis (fluorosulfonyl) imide obtained in step b) to form a composition C; d) crystallization of the lithium salt of bis (fluorosulfonyl) imide from composition C; e) optional filtration step, to lead to the composition according to one of the above objects, said process being characterized in that composition C comprises at least 30% by weight of a dry extract ES, said dry extract ES being characterized in that:

- It comprises the lithium salt of bis (fluorosulfonyl) imide, preferably in a content greater than or equal to 99.90% by weight relative to the total weight of said dry extract ES;

- the sum of the total mass contents of chlorides, sulphates and fluorides is strictly greater than 0 and less than or equal to 500 ppm, preferably less than or equal to 300 ppm, advantageously less than or equal to 200 ppm by weight relative to the total weight of said dry extract ES.

The dry extract measurement is typically carried out on a Metler Toledo type HR73 thermobalance according to the following steps:

- i) an aluminum basket is placed in the Metler Toledo type HR73 thermobalance device;

- ii) the nacelle is then tared;

- iii) a fiberglass disc is placed on the basket and is dried at 110 ° C until a constant weight is obtained;

- iv) the nacelle and the fiberglass disc are calibrated;

- v) the disc is then soaked with 1 g of solution to be analyzed and is heated to 110 ° C .;

- vi) the dry extract is obtained when the weight becomes constant.

According to one embodiment, the total mass content of chlorides in the above-mentioned composition C is greater than 20 ppm, preferably greater than or equal to 30 ppm, preferably greater than or equal to 50 ppm, advantageously greater than or equal to 100 ppm, for example greater than or equal to 150 ppm.

Preferably, composition C is characterized in that the sum of the total mass contents of chlorides, sulphates, fluorides and potassium ion is greater than or equal to 100 ppm, preferably greater than or equal to 150 ppm, advantageously greater than or equal to 180 ppm.

According to one embodiment, composition C comprises at least 35% by weight of said dry extract ES, preferably at least 40% by weight, and advantageously at least 50% by weight, relative to the total weight of composition C.

The lithium bis (fluorosulfonyl) imide salt in solution in organic solvent S1 can be obtained by any known process for preparing said salt, for example as described in WO2015 / 158979 or WO2009 / 1233328. LiFSI salt can be obtained either in solid form or in the form of a solution in an organic solvent S1.

The composition according to one of the above objects can be obtained by a process comprising the following steps:

- i) process for preparing the lithium salt of bis (fluorosulfonyl) imide, said salt possibly being solid or in solution in an organic solvent S1;

- ii) step of bringing into contact with an organic solvent S1 in the case where the LiFSI salt obtained in step i) is solid;

- iii) purification process as described above.

The aforementioned organic solvent S2 can be chosen from the group consisting of esters, nitriles, ethers, chlorinated solvents, aromatic solvents, and mixtures thereof. Preferably, the solvent S2 is chosen from dichloromethane, ethyl acetate, butyl acetate, tetrahydrofuran, acetonitrile, diethyl ether, and mixtures thereof. Preferably, the organic solvent S2 is butyl acetate.

According to the invention, each of the aforementioned steps a) and b) can be repeated at least once.

According to one embodiment, the organic solvent S1 is chosen from the group consisting of esters, nitriles, ethers, chlorinated solvents, aromatic solvents, and mixtures thereof. Preferably, the solvent S1 is chosen from ethers, esters, and mixtures thereof. For example, there may be mentioned methyl-t-butyl ether, cyclopentylmethyl ether, ethyl acetate, propyl acetate, butyl acetate, dichloromethane, tetrahydrofuran, acetonitrile, diethyl ether, and their mixtures. Of preferably, the SOI solvent is chosen from methyl-t-butyl ether, cyclopentylmethyl ether, ethyl acetate, propyl acetate, butyl acetate, and their mixtures, the organic solvent S1 preferably being l butyl acetate.

Step c) above can be carried out in two stages:

- a pre-concentration preferably carried out at a temperature ranging from 25 ° C to 45 ° C, preferably from 30 ° C to 40 ° C

- a concentration step carried out in a short path thin film evaporator, under the following conditions: o temperature between 30 ° C and 95 ° C, preferably between 30 ° C and 90 ° C, preferably between 40 ° C and 85 ° C, in particular between 60 ° C and 80 ° C, o pressure between 10 ³ mbar abs and 5 mbar abs, and in particular between 5.10 ¹ and 2 mbar abs; o residence time less than or equal to 5 min, preferably less than or equal to 3 min.

Preferably, the pre-concentration step is carried out under reduced pressure, for example a pressure less than or equal to 50 mbar abs, in particular at a pressure less than or equal to 30 mbar abs.

The pre-concentration step can be carried out by any means allowing concentration, for example using an evaporator.

In the context of the invention, and unless otherwise specified, the term “residence time” is understood to mean the time which elapses between the entry of the solution of lithium salt of bis (fluorosulfonyl) imide (in particular obtained at the end of step b) above) in the evaporator and the exit of the first drop of the solution.

According to a preferred embodiment, the temperature of the condenser of the short path thin film evaporator is between -50 ° C and 5 ° C, preferably between -35 ° C and 5 ° C. In particular, the temperature of the condenser is -5 ° C.

The short path thin film evaporators according to the invention are also known under the name "Wiped film short path" (WFSP). They are typically called so because the vapors generated during evaporation make a "short trip" (short distance) before being condensed in the condenser.

Among the short path thin film evaporators, mention may in particular be made of the evaporators marketed by the companies Buss SMS Ganzler ex Luwa AG, UIC Gmbh or VTA Process. Typically, short path thin film evaporators may have a solvent vapor condenser placed inside the apparatus itself (especially in the center of the apparatus), unlike other types of film evaporators. thin (which are not short-path) in which the condenser is located on the outside of the device.

In this type of apparatus, the formation of a thin film of product to be distilled on the internal hot wall of the evaporator can typically be ensured by continuous spreading on the evaporation surface using mechanical means. specified below.

The evaporator can in particular be provided at its center with an axial rotor on which are mounted the mechanical means which allow the formation of the film on the wall. These may be rotors equipped with fixed blades: lobed rotors with three or four blades made of flexible or rigid materials, distributed over the entire height of the rotor or else rotors equipped with mobile blades, vanes, wiper brushes, guided wipers. In this case, the rotor can be constituted by a succession of pivot-articulated vanes mounted on a shaft or axis by means of radial supports. Other rotors can be equipped with movable rollers mounted on secondary axes and said rollers are pressed against the wall by centrifugation. The speed of rotation of the rotor, which depends on the size of the apparatus, can be easily determined by a person skilled in the art. The different mobiles can be made of various materials, metallic for example steel, alloy steel (stainless steel), aluminum, or polymeric, for example polytetrafluroethylene PTFE or glass materials (enamel); metallic materials coated with polymeric materials.

The crystallization step d) can be carried out by bringing the composition obtained at the end of step c) into contact with an organic solvent (“crystallization solvent”) chosen from chlorinated solvents, such as for example dichloromethane, and aromatic solvents, such as, for example, toluene.

Preferably, the crystallization is carried out at a temperature less than or equal to 25 ° C, preferably less than or equal to 15 ° C.

Installation for regulating the temperature of the battery of a vehicle

The invention relates to a method of heat transfer, comprising regulating the temperature of the battery of a motor vehicle, in a heat transfer installation.

The method according to the invention is thus a method for cooling the battery of a vehicle; or a method of heating this battery; or one cooling and heating process (cooling and heating alternating over time, as needed).

The method according to the invention is implemented by means of the installation presented below.

The heat transfer installation comprises a vapor compression circuit which contains a first heat transfer composition (or refrigeration circuit) and a secondary circuit containing a second heat transfer composition (or coolant circuit).

According to one embodiment of the invention, shown schematically in Figure 1, the vapor compression circuit 1 is coupled with the secondary circuit 2. The vapor compression circuit 1 comprises at least a first heat exchanger 3, a expansion valve 4, an intermediate heat exchanger 5 and a compressor 6. The first heat exchanger 3 is preferably of the air / refrigerant type, and it allows heat exchange with an energy source such as air from the air. environment. The secondary circuit 2 comprises at least one additional heat exchanger 7.

By "energy source" is meant a solid and / or liquid and / or gaseous body which can absorb or give up calories as required. Examples of energy sources are exterior air, cabin air, battery and vehicle electronics.

In refrigeration mode (coil cooling), heat is transferred from the coil to the additional heat exchanger 7. Optionally, this heat transfer causes the evaporation of the second heat transfer composition which circulates in the circuit. secondary 2. Alternatively, the second heat transfer composition remains in the liquid state during this heat transfer.

The second heat transfer composition then goes into the intermediate heat exchanger 5, which can act as the condenser for the secondary circuit 2. Alternatively, the second heat transfer composition remains in the liquid state during heat transfer at the intermediate heat exchanger 5.

In the vapor compression circuit 1, the first heat transfer composition is compressed by the compressor 6, it passes through the first heat exchanger 3 acting as a condenser (i.e. transfers calories to a source like the outside air), then the expansion valve 4 where it is expanded, then the intermediate heat exchanger 5 acting as an evaporator for the vapor compression circuit 1. So, in the intermediate heat exchanger 5, heat is transferred from the second heat transfer composition to the first heat transfer composition, optionally causing the condensation of the second heat transfer composition and the evaporation of the first heat transfer composition. The first heat transfer composition then goes again to the compressor 6, while the second heat transfer composition goes to the additional heat exchanger 7, and allows the cooling of the battery.

According to certain embodiments, the installation according to the invention is also suitable for heating the battery, in particular when the outside temperature is low, for example less than 10 ° C, or at 5 ° C, or at 0 ° C, or at -5 ° C, or at -10 ° C, or at -15 ° C, or at -207, or at -25 ° C.

Thus, the invention also covers a method of heating the battery by means of the installation. Battery heating can alternate with battery cooling over time as required.

In the case of heating the coil, heat is transferred to the coil from the additional heat exchanger 7, which can lead to the condensation of the second heat transfer composition which circulates in the secondary circuit 2. Alternatively, the second Heat transfer composition remains in the liquid state during this heat transfer.

The second heat transfer composition then goes into the intermediate heat exchanger 5, which can act as an evaporator for the secondary circuit 2. Alternatively, the second heat transfer composition remains in the liquid state. during heat transfer at the intermediate heat exchanger 5.

In the vapor compression circuit 1, the first heat transfer composition is expanded in the expansion valve 4, it passes through the first heat exchanger 3 acting as an evaporator (i.e. absorbs calories from a source like the outside air), then the compressor 6 where it is compressed, then the intermediate heat exchanger 5 playing the role of condenser for the vapor compression circuit 1. Thus, in the intermediate heat exchanger 5, heat is transferred from the first heat transfer composition to the second heat transfer composition, causing the condensation of the first heat transfer composition and optionally the evaporation of the second heat transfer composition. The first heat transfer composition then goes again to the expansion valve 4, while the second heat transfer composition goes to the additional heat exchanger 7, and allows heating of the battery.

According to some embodiments, the installation according to the invention is suitable for performing one or more phases of cooling the battery alternating with one or more phases of heating the battery.

According to certain embodiments, the installation according to the invention is also suitable for cooling (air conditioning) of the vehicle interior and / or of the electronic components of the vehicle. A heat exchanger dedicated to the exchange of heat with the air in the passenger compartment and / or a heat exchanger dedicated to the exchange of heat with the electronic components, is then present.

According to some embodiments, the installation according to the invention is also suitable for heating the passenger compartment of the vehicle and / or the electronic components of the vehicle. A heat exchanger dedicated to the exchange of heat with the air in the passenger compartment and / or a heat exchanger dedicated to the exchange of heat with the electronic components, is then present.

In some embodiments, the same heat exchanger can perform the function of the intermediate exchanger 5 described above, depending on the mode of operation.

In certain embodiments, the same heat exchanger can perform the function of the first heat exchanger 3, depending on the mode of operation.

Additional exchangers can also be added to ensure the different operating modes. A set of pipes and valves can be used to ensure the change of operating mode for each exchanger.

In some embodiments, the vapor compression circuit 1 is reversible and may further include means for reversing its operation.

The means for reversing the operation of the reversible vapor compression circuit 1 are means for reversing the operation of the vapor compression circuit 1 between a configuration in refrigeration mode and a configuration in heat pump mode.

The aforementioned inversion means can be means for modifying the path of the first heat transfer composition in the reversible vapor compression circuit 1, or means reversal of the direction of circulation of the first heat transfer composition in said circuit 1.

The aforementioned reversing means may be a four-way valve, a reversing valve, a shut-off valve, a pressure regulator, or combinations thereof.

For example, when reversing the mode of operation of the vapor compression circuit 1, the role of a heat exchanger can be changed: for example, a heat exchanger can play the role of a condenser in a mode refrigeration or the role of an evaporator in a heat pump mode or vice versa.

Alternatively, when reversing the mode of operation of the vapor compression circuit 1, the role of a heat exchanger can remain the same. The heat exchanger being simply connected to other energy sources, through valves, can absorb or transfer calories depending on its function in the vapor compression circuit 1.

In some preferred embodiments, the first heat transfer composition can flow through vapor compression circuit 1 in a one way direction.

In other embodiments, the first heat transfer composition can flow through the vapor compression circuit 1 in both directions, that is, a first direction and an opposite direction.

The reversible vapor compression circuit 1 can typically contain pipes, pipes, hoses, tank or others, in which the first heat transfer composition circulates, between the various exchangers, regulators, valves, etc.

When the installation is also implemented for heating the vehicle battery, depending on the operating mode of the vapor compression circuit 1, refrigeration or heat pump, the first heat exchanger 3 can play the role of evaporator or energy recovery (condenser). The same is true for the intermediate heat exchanger 5.

It is possible to use any type of heat exchanger in the vapor compression circuit 1, and in particular cocurrent heat exchangers or, preferably, countercurrent heat exchangers.

According to a preferred embodiment, the invention provides a counter-current heat exchanger, either to the first heat exchanger 3, or to the intermediate heat exchanger 5. In fact, the heat transfer compositions described in present application are particularly effective with counter-current heat exchangers. Preferably, both the first heat exchanger 3 and the intermediate heat exchanger 5 are countercurrent heat exchangers.

According to the invention, 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, countercurrent 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 a counter-current tendency are also included among the counter-current heat exchangers within the meaning of the present application.

The compressor 6 can be hermetic, semi-hermetic or open. Hermetic compressors include a motor part and a compression part which are confined in a non-removable hermetic enclosure. Semi-hermetic compressors include a motor part and a compression part which are directly assembled against each other. The coupling between the engine part and the compression part is accessible by separating the two parts by disassembly. Open compressors have an engine part and a compression part which are separate. They can operate by belt drive or by direct coupling.

As a compressor, it is possible to use in particular a dynamic compressor, or a positive displacement compressor.

Dynamic compressors include axial compressors and centrifugal compressors, which can be single or multi-stage. Mini centrifugal compressors can also be used.

Positive displacement compressors include rotary compressors and reciprocating compressors.

Reciprocating compressors include diaphragm compressors and reciprocating compressors.

Rotary compressors include screw compressors, rotary lobe compressors, scroll (or scroll) compressors, liquid ring compressors, and vane compressors. The screw compressors can preferably be twin-screw or single-screw. In the installation which is used, the compressor 6 can be driven by an electric motor or by a gas turbine (for example powered by the exhaust gases of the vehicle) or by gearing.

In the installation that is used, the compressor 6 may include a vapor or liquid injection device. Injection consists of introducing refrigerant in the liquid or vapor state into the compressor at an intermediate level between the start and the end of compression.

The secondary circuit 2 comprises at least one additional heat exchanger 7.

Each additional heat exchanger 7 can be an exchanger of the fluid / solid type, or of the fluid / fluid type, or of the fluid / air type (for heating or cooling the air, for example the air in the passenger compartment). In these last two cases, again the additional heat exchanger (s) 7 can be cocurrent heat exchangers or, preferably, countercurrent heat exchangers.

At least one additional heat exchanger 7 can be configured to cool the battery. The same additional heat exchanger 7 or other additional heat exchangers 7 can be configured to heat the coil (although it is preferred that a same additional heat exchanger 7 can both cool and heat the coil), or to cool and / or heat the passenger compartment and / or the electronic components of the vehicle.

To cool or heat the battery (and / or electronic components), it is possible to cool or heat the air that is blown to the battery (and / or electronic components); or to put the additional exchanger 7 concerned directly in contact with the battery (and / or the electronic components), or to integrate it into the battery (and / or the electronic components).

In some embodiments, the second heat transfer composition is in direct contact with the vehicle battery. In other words, the vehicle battery is immersed in the second heat transfer composition. In this case, the corresponding additional heat exchanger 7 is limited to an enclosure containing all or part of the battery, the second heat transfer composition being contained in the enclosure and in contact with the external wall of the battery.

This makes it possible to reconcile the good dielectric and thermal properties of the heat transfer composition in order to obtain a better result. In this case, it is preferable that the second heat transfer composition has a boiling pressure of less than 2 bar at a temperature of 30 ° C. If the boiling pressure of the second heat transfer composition is not low enough, direct contact requires a great deal of effort in the design of the battery housing to withstand the pressure. In this case, the pressure stress is managed more easily by using an additional heat exchanger 7 in the form for example of cooling plates.

In some embodiments, the secondary circuit 2 does not include a compressor. In other words, the secondary circuit 2 is not a vapor compression circuit.

In some embodiments, the second heat transfer composition is at a substantially uniform pressure in the secondary circuit, said pressure being equal to the saturation pressure of the second heat transfer composition at the temperature of the second transfer composition. heat. A small deviation is possible in the event of a pressure drop. The temperature of the second heat transfer composition is preferably uniform in the secondary circuit.

In some embodiments, the second heat transfer composition remains at a constant temperature during the process.

By “saturation pressure” is meant the pressure at which a gas phase of a composition is in equilibrium with a liquid phase at a given temperature in a closed system.

In certain embodiments, the secondary circuit 2 can comprise one or more valves, in particular when it comprises several additional heat exchangers 7, in order to direct the second heat transfer composition towards one or more specific additional heat exchangers 7. ; and / or in order to allow the direction of circulation of the second heat transfer composition to be changed in all or part of the secondary circuit 2.

In certain preferred embodiments, the second heat transfer composition can circulate in all or part of the secondary circuit 2 in a single direction.

In some embodiments, the second heat transfer composition can circulate in all or part of the secondary circuit 2 in both directions, that is to say a first direction and an opposite direction.

In some embodiments, the circulation of the second heat transfer composition in the secondary circuit 2 of the intermediate heat exchanger 5 to the additional heat exchanger (s) 7, and / or to the additional heat exchanger (s) 7 to the exchanger intermediate heat 5 can be carried out by means of a pump, or by gravity, or by capillarity.

In this installation according to the invention, the vapor compression circuit 1 can be coupled with the secondary circuit 2 by the intermediate heat exchanger 5. Thus, the intermediate heat exchanger 5 can be crossed at the same time by the first heat transfer composition and by the second heat transfer composition.

On cooling the coil, the intermediate heat exchanger 5 can evaporate the first heat transfer composition (and optionally condense the second heat transfer composition), and the additional heat exchanger 7 is configured to transfer heat. heat from the battery to the second heat transfer composition.

When heating the coil, the intermediate heat exchanger 5 can condense the first heat transfer composition (and optionally evaporate the second heat transfer composition), and the additional heat exchanger 7 is configured to transfer heat. heat from the second heat transfer composition to the battery (optionally by condensing the second heat transfer composition).

In some embodiments, the second heat transfer composition is in the liquid state throughout the secondary circuit 2. The temperature of the second heat transfer composition is changed when passing through the additional heat exchanger 7 and through the intermediate heat exchanger 5. This is in particular the preferred option when the coil is immersed in the second heat transfer composition.

In the context of the present application, each evaporation and each condensation can be total or partial.

Evaporation can thus consist of starting from the liquid state to go to the vapor state; or from the liquid / vapor two-phase state to the vapor state; or from the liquid state to the two-phase liquid / vapor state; or from a liquid / vapor two-phase state to another liquid / vapor two-phase state.

A condensation can thus consist of starting from the vapor state to go to the liquid state; or from the vapor state to the liquid / vapor two-phase state; or from the liquid / vapor two-phase state to the liquid state; or from a liquid / vapor two-phase state to another liquid / vapor two-phase state. Evaporation and condensation can take place at constant temperature, or at variable temperature in the case of non-azeotropic mixtures of heat transfer compounds.

In some embodiments, in the intermediate heat exchanger 5, one composition (the first heat transfer composition or the second heat transfer composition) is at a lower temperature than the other; preferably, the temperature differential is less than 12 ° C, more preferably less than 8 ° C, and more preferably less than 5 ° C. On the assumption that the temperature of a composition is not constant in the intermediate heat exchanger 5, for the estimation of the above temperature differential, the median temperature between the inlet and the outlet of the temperature is taken as a reference. 'intermediate heat exchanger.

In certain embodiments, the cooling and / or the heating make it possible to maintain the temperature of the battery within an optimum temperature range, in particular when the vehicle is in operation (engine on), and in particular when the vehicle is moving.

In certain embodiments, the temperature of the vehicle battery is thus maintained between a minimum temperature ti and a maximum temperature t2.

In some embodiments, the minimum temperature ti is greater than or equal to 0 ° C and the maximum temperature t2 is less than or equal to 60 ° C, preferably the minimum temperature ti is greater than or equal to 15 ° C and the maximum temperature fe is less than or equal to 40 ° C, and more preferably the minimum temperature ti is greater than or equal to 16 ° C and the maximum temperature fe is less than or equal to 28 ° C.

In some embodiments, the outside temperature while maintaining the temperature of the battery between the minimum temperature ti and the maximum temperature t2 is greater than or equal to 20 ° C, preferably greater than or equal to 30 ° C, more preferably greater than or equal to 35 ° C, more preferably greater than or equal to 40 ° C.

The outside temperature during the period of maintaining the temperature of the vehicle battery between the minimum temperature ti and the maximum temperature t2 can in particular be from -25 to -20 ° C .; or from -20 to -15 ° C; or from -15 to -10 ° C; or from -10 to -5 ° C; orfrom -5 to 0 ° C; or from 0 to 5 ° C; or from 5 to 10 ° C; or from 10 to 15 ° C; or from 15 _< 0 ° C; or from 20 to 25 ° C; or from 25 to 30 ° C; or from 30 to 35 ° C; or from 35 to 40 ° Q or from 40 to 45 ° C; or 45 to 50 ° C. The term “exterior temperature” means the ambient temperature outside the vehicle before and while the temperature of the vehicle battery is maintained between the minimum temperature ti and the maximum temperature t2.

By "battery temperature" is generally meant the temperature of an outer wall of one or more of the electrical energy storage elements.

The temperature of the battery can be measured using a temperature sensor. If several temperature sensors are present at the battery level, the battery temperature can be considered as being the average of the different measured temperatures.

In certain embodiments, the installation and method of the present invention allow the vehicle battery to be cooled or heated (and preferably cooled) and maintained within an optimum temperature range (as detailed above. ) when charging the battery.

In particular, the battery charge can be fast charging. Thus, when the battery is fully charged (from a time when the battery is completely discharged) for a period less than or equal to 30 min, and preferably less than or equal to 15 min, the method according to the invention allows to keep the battery temperature within an optimum temperature range. This has an advantage since during rapid charging the battery tends to heat up quickly and reach high temperatures which can influence its operation and performance.

In some embodiments, the second heat transfer composition is maintained at a temperature between 10 and 40 ° C, preferably between 20 and 30 ° C, throughout the secondary circuit 2.

Heat transfer compositions

The invention uses a first heat transfer composition and a second heat transfer composition, each heat transfer composition comprising a heat transfer fluid optionally associated with lubricants and / or additives. The heat transfer fluid can include one or more heat transfer compounds.

The first heat transfer composition is present and circulates in the vapor compression circuit. In some embodiments, the heat transfer fluid of the first heat transfer composition comprises HFO-1234yf.

In some embodiments, this heat transfer fluid comprises at least 50% HFO-1234yf, or at least 60% FIFO-1234yf, or at least 70% FIFO-1234yf, or at least 80% FIFO- 1234yf, or at least 90% FIFO-1234yf, or at least 95% FIFO-1234yf, by weight.

In some embodiments, this heat transfer fluid consists essentially, or even consists, of HFO-1234yf.

In other preferred embodiments, this heat transfer fluid also comprises one or more other heat transfer compounds, such as hydrofluorocarbons and / or hydrofluoroolefins and / or hydrocarbons and / or hydrochlorofluoroolefins and / or CO2.

Among the hydrofluorocarbons, mention may in particular be made of difluoromethane (HFC-32), pentafluoroethane (HFC-125), 1, 1, 2,2-tetrafluoroethane (HFC-134), 1, 1, 1, 2-tetrafluoroethane (FIFC-134a), 1, 1 -difluoroethane (FIFC-152a), fluoroethane (HFC-161), 1, 1, 1, 2,3,3,3-heptafluoropropane (FIFC-227ea), 1 , 1, 1 -trifluoropropane (FIFC-263fb) and mixtures thereof.

Among the hydrofluoroolefins, mention may in particular be made of 1, 3,3,3-tetrafluoropropene (HFO-1234ze), in cis and / or trans form, and preferably in trans form; and trifluoroethylene (HFO-1123).

Among the hydrochlorofluoroolefins, mention may in particular be made of 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd), in Z and / or E form, and preferably in E form.

In preferred embodiments, the heat transfer fluid of the first heat transfer composition comprises HFO-1234yf and HFC-32. Preferably, the heat transfer fluid is a binary composition of HFO-1234yf and HFC-32 (i.e., it consists, or consists essentially of HFO-1234yf and HFC-32) .

Thus, HFO-1234yf can have a content of 60-90% by weight, and HFC-32 can have a content of 40-10% by weight, preferably HFO-1234yf can have a content of 70-80%. by weight, and the HFC-32 may have a content of 20 to 30% by weight, and more preferably the HFO-1234yf may have a content of 75 to 80% by weight, and the HFC-32 may have a content of 20 to 25% by weight. According to preferred embodiments, the HFO-1234yf is present at a content of about 78.5% by weight of and the HFC-32 is present at a content of about 21.5% by weight. The weight percentages are given based on the heat transfer fluid of the first heat transfer composition.

The additives which can be present in the first heat transfer composition of the invention can in particular be chosen from nanoparticles, stabilizers, surfactants, tracers, fluorescent agents, odorous agents and solubilizing agents.

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

In some embodiments, the HFO-1234yf contains impurities. When they are 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 HFO-1234yf.

The heat transfer fluid of the first heat transfer composition may optionally include HFO-1243zf (3,3,3-trifluoropropene) and / or 3,3,3-trifluoropropyne.

The content of HFO-1243zf in the heat transfer fluid can be less than or equal to 10,000 ppm, or 5,000 ppm, or 1,000 ppm, or 500 ppm, or 100 ppm, or 50 ppm.

For example, the content of HFO-1243zf in the heat transfer fluid can be: 0 to 1 ppm, or 1 to 10 ppm, or 10 to 50 ppm, or 50 to 100 ppm, or from 100 to 500 ppm, or from 500 to 1000 ppm, or from 1000 to 5000 ppm, or from 5000 to 10,000 ppm.

The content of 3,3,3-trifluoropropyne in the heat transfer fluid may be less than or equal to 10,000 ppm, or 5,000 ppm, or 1,000 ppm, or 500 ppm, or 100 ppm, or 50 ppm .

For example, the content of 3,3,3-trifluoropropyne in the heat transfer fluid can be: from 0 to 1 ppm, or from 1 to 10 ppm, or from 10 to 50 ppm, or from 50 to 100 ppm, or 100 to 500 ppm, or 500 to 1000 ppm, or 1000 to 5000 ppm, or 5000 to 10,000 ppm.

The above ppm values are given by weight.

One or more lubricants may be present in the first heat transfer composition. These lubricants can be chosen from esters of polyols (POE), polyalkylene glycols (PAG), or polyvinyl ethers (PVE). The lubricants can represent from 1 to 50%, preferably from 2 to 40% and more preferably from 5 to 30% (by weight) of the first heat transfer composition.

The heat transfer fluid of the second heat transfer composition preferably comprises one or more heat transfer compounds having a boiling point of 0 to 40 ° C, more preferably 5 to 35 ° C, and more preferably from 8 to 34 ° C.

By "boiling point of a compound" is meant the temperature at which the compound boils under a pressure of 1 bar.

In some embodiments, the heat transfer fluid of the second heat transfer composition has a boiling point of 0 to 40 ° C, preferably 5 to 35 ° C, and more preferably 8 to 34 ° C. .

In case of mixing several compounds, the boiling temperature of the mixture corresponds to the average between the starting boiling temperature and the end boiling temperature at a pressure of 1 bar.

In some embodiments, the heat transfer compound (s) having a boiling point of 0 to 40 ° C can be selected from hydrochlorofluoroolefins, hydrofluoroolefins, and combinations thereof.

In some embodiments, the hydrochlorofluoroolefins can be selected from 1 -chloro-3,3,3-trifluoropropene (HCFO-1233zd) and 1 -chloro-2,3,3,3-tetrafluoropropene (HCFO-1224yd) and combinations of these.

HCFO-1233zd can be in E and / or Z form.

For example, the HCFO-1233zd may comprise more than 50 mol.% Of the form E, preferably more than 60 mol.% Of the form E, preferably more than 70 mol.% Of the form E, preferably more than 80 mol% of form E, preferably more than 85 mol% of form E, preferably more than 90 mol% of form E, preferably more than 95 mol% of form E, preferably more than 98 mole% of the E form and more preferably more than 99 mole% of the E form. Preferably, it is wholly, or essentially wholly, in the E form.

For example, HCFO-1233zd may comprise more than 50 mol% of the Z form, preferably more than 60 mol% of the Z form, preferably more than 70 mol% of the Z form, preferably more than 80 mol% of the Z form, preferably more than 85 mol% of the Z form, preferably more than 90 mol% of the Z form, preferably more than 95 mol% of the Z form, preferably more than 98 mol% of the Z form and more preferably more than 99 mol% of Z form. Preferably, it is entirely, or essentially entirely, in Z form.

HCFO-1224yd can be in E and / or Z form.

Preferably the HCFO-1224yd comprises more than 50 mol.% Of the Z form, preferably more than 60 mol.% Of the Z form, preferably more than 70 mol.% Of the Z form, preferably more than 80 mol. .% of form Z, preferably more than 85 mol.% of form Z, preferably more than 90 mol.% of form Z, preferably more than 95 mol.% of form Z, preferably more than 98 mole% of the Z form and more preferably more than 99 mole% of the Z form. Preferably, it is entirely in the Z form.

In some embodiments, the hydrofluoroolefin can be 1, 1, 1, 4,4,4-hexafluorobut-2-ene (HFO-1336mzz) in E and / or Z form.

The HFO-1336mzz can thus comprise more than 50 mol.% Of the Z form, preferably more than 60 mol.% Of the Z form, preferably more than 70 mol.% Of the Z form, preferably more than 80 mol. .% of form Z, preferably more than 85 mol.% of form Z, preferably more than 90 mol.% of form Z, preferably more than 95 mol.% of form Z, preferably more than 98 mole% of the Z form and more preferably more than 99 mole% of the Z form. It can be entirely in the Z form.

Alternatively, the HFO-1336mzz may comprise more than 50 mol.% Of the form E, preferably more than 60 mol.% Of the form E, preferably more than 70 mol.% Of the form E, preferably more than 80 mol% of form E, preferably more than 85 mol% of form E, preferably more than 90 mol% of form E, preferably more than 95 mol% of form E, preferably more 98 mol% of the E form and more preferably more than 99 mol% of the E form. It can be entirely in E form.

In some embodiments, the heat transfer compounds used in the second heat transfer composition have a latent heat of evaporation at 20 ° C greater than 100 kJ / kg, preferably greater than 110 kJ / kg, again of preferably greater than 120 kJ / kg, still more preferably greater than 130 kJ / kg, still more preferably greater than 140 kJ / kg, still more preferably greater than 150 kJ / kg, and still more preferably greater than 160 kJ / kg.

The latent heat values of the heat transfer compounds preferentially used in the second composition as heat transfer fluid are presented in the table below for a temperature of 20 ° C. The highest latent heat is observed for HCFO-1233zd (E). [Table 1]

In some embodiments, the heat transfer fluid of the second heat transfer composition comprises a single heat transfer compound.

In some embodiments, the heat transfer fluid of the second heat transfer composition can be a binary mixture of heat transfer compounds.

In some embodiments, the heat transfer fluid of the second heat transfer composition can be a ternary mixture of heat transfer compounds.

The second heat transfer composition is present and circulates in the secondary circuit.

In some embodiments, the second heat transfer composition does not undergo compression or expansion.

In some embodiments, the second heat transfer composition comprises at least 50% heat transfer fluid, or at least 60% heat transfer fluid, or at least 70% heat transfer fluid, or at least 80% heat transfer fluid, or at least 90% heat transfer fluid, or at least 95% heat transfer fluid, by weight.

In some embodiments, the heat transfer fluid of the second heat transfer composition consists essentially of, or even consists of, heat transfer compounds.

The additives which may be present in the second heat transfer composition of the invention are the same as those described above in connection with the first heat transfer composition, the same concentration ranges applying. Furthermore, the second heat transfer composition may comprise a C3 and C6 alkene stabilizer, in particular a butene or a pentene.

EXAMPLES

The present invention is illustrated by the following example, to which it is, however, not limited.

Examples 1 and 2 - preparation of LiFSI (according to the invention)

Crude LiFSI in solution in butyl acetate is obtained at the end of the process described in WO 2015/158979. The LiFSI solution is subjected to a purification process comprising liquid-liquid extraction of said salt with deionized water to form an aqueous solution, then liquid-liquid extraction of the lithium salt of bis (fluorosulfonyl) imide to from said aqueous solution with butyl acetate. The solution obtained was subjected to a concentration step to lead to a composition comprising more than 30% by weight of a dry extract, characterized in that it comprises more than 99.75% by weight of LiFSI and in that the sum of the total mass contents of chlorides, sulphates and fluorides is strictly greater than 0 and less than 500 ppm. The composition is then subjected to a crystallization and filtration step, to yield the LiFSI of Example 1.

The LiFSI of Example 2 was obtained by a similar process.

Example 3 - preparation of LiFSI (comparative)

Crude LiFSI in solution in butyl acetate is obtained at the end of the process described in WO 2015/158979. The LiFSI solution is subjected to a purification process comprising liquid-liquid extraction of said salt with deionized water to form an aqueous solution, then liquid-liquid extraction of the lithium salt of bis (fluorosulfonyl) imide to from said aqueous solution with butyl acetate. The solution obtained was subjected to a concentration step to lead to a composition comprising a dry extract characterized in that it comprises less than 99.75% by weight of LiFSI, and in that the sum of the total contents by mass of chlorides , sulphates and fluorides is strictly greater than 600 ppm.

The composition is then subjected to a crystallization and filtration step, to yield the LiFSI of Example 3. Example 4 - characterization

Cyclic voltammetry tests were carried out. For this, CR2032 button cells were manufactured equipped with a 20 mm diameter aluminum foil as a working electrode, an 8 mm diameter lithium metal pellet as a reference electrode and a fiberglass separator. of diameter 18 mm soaked with 12 drops (0.6 ml_) of a solution of LiFSI of different compositions at 1 mol / L in a mixture of solvent composed of ethylene carbonate and methyl ethyl carbonate (CAS = 623-53 -0) in a 3/7 ratio by volume. Then a voltage sweep is carried out at the terminals of the button cell at 4.5 V. Two preliminary sweeps are carried out allowing the formation of passivation layers such as SEI and the passivation of aluminum. Then, the 4.5V oxidation current (after the two scans) generated was measured and recorded. The values are as follows:

[Table 2]

The observed oxidation current can reflect many phenomena: corrosion of aluminum, degradation of the electrolyte and swelling of the battery. All these phenomena are responsible for the degradation of the lifespan of Li-ion batteries. The lower this current, the longer the battery life is improved. At 4.5 V, the results show that the use of a LiFSI having in particular a chloride content of less than 20 ppm advantageously makes it possible to reduce this oxidation current relative to a LiFSI having a chloride content of 20 ppm, and therefore improve the lifespan of Li-ion batteries.

Claims

1. A method of regulating the temperature of a battery of an electric or hybrid motor vehicle, by means of a system comprising a vapor compression circuit in which circulates a first heat transfer composition and a secondary circuit in which circulates a second heat transfer composition, the method comprising:

- Cl chlorides in a mass content strictly less than 20 ppm; in which the total mass content of Cl chlorides, F fluorides and SC sulphates> 4 ² is preferably less than or equal to 150 ppm.

2. The method of claim 1, wherein the first heat transfer composition comprises 2,3,3,3-tetrafluoropropene.

3. Method according to one of claims 1 or 2, wherein the first heat transfer composition comprises one or more heat transfer compounds other than 2,3,3,3-tetrafluoropropene, these compounds preferably being chosen from difluoromethane, pentafluoroethane, 1, 1, 2,2-tetrafluoroethane, 1, 1 , 1, 2-tetrafluoroethane, 1, 1-difluoroethane, fluoroethane,

1.1.1.2.3.3.3-heptafluoropropane, 1, 1, 1-trifluoropropane and their mixtures, and more preferably this compound being difluoromethane.

4. The method of claim 3, wherein the

2.3.3.3-Tetrafluoropropene is present at a content of approximately 78.5% by weight in the first composition and difluoromethane is present at a level of approximately 21.5% by weight in the first composition.

5. Method according to one of claims 1 to 4, wherein the second heat transfer composition comprises one or more heat transfer compounds having a boiling point of 0 to 40 ° C, preferably chosen from hydrochlorofluoroolefins , hydrofluoroolefins, and combinations thereof; more preferably chosen from 1-chloro-3,3,3-trifluoropropene, preferably in E form; 1-chloro-2,3,3,3-tetrafluoropropene, preferably in Z form, and 1, 1, 1, 4,4,4-hexafluorobut-2-ene in E and / or Z form.

6. Method according to one of claims 1 to 5, wherein the second heat transfer composition is at an essentially uniform pressure in the secondary circuit, said pressure being preferably equal to the saturation pressure of the second composition.

7. Method according to one of claims 1 to 6, wherein the battery is maintained at a temperature between a minimum temperature ti and a maximum temperature t2.

8. The method of claim 7, wherein the minimum temperature ti is greater than or equal to 0 ° C and the maximum temperature t2 is less than or equal to 60 ° C, more preferably the minimum temperature ti is greater than or equal to 15 °. C and the maximum temperature t2 is less than or equal to 40 ° C, and more preferably the minimum temperature ti is greater than or equal to 16 ° C and the maximum temperature t2 is less than or equal to 28 ° C.

9. Method according to one of claims 1 to 8, implemented during the charging of 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.

10. A method according to one of claims 1 to 9, wherein the second heat transfer composition is in direct contact with the vehicle battery.

11. Installation for regulating the temperature of a battery of an electric or hybrid motor vehicle, comprising:

- a vapor compression circuit (1) in which circulates a first heat transfer composition; and

- a secondary circuit (2) in which circulates a second heat transfer composition; the vapor compression circuit (1) being coupled with the secondary circuit (2) by an intermediate heat exchanger (5), so as to allow the exchange of heat between the first heat transfer composition and the second heat transfer composition heat transfer ; and the installation comprising an additional heat exchanger (7) configured to exchange heat. heat between the battery and the second heat transfer composition; the battery comprising at least one electrochemical cell comprising a negative electrode, a positive electrode and an electrolyte comprising a lithium salt composition, said lithium salt composition comprising:

12. Installation according to claim 11, wherein the secondary circuit (2) does not include a compressor.

13. Installation according to one of claims 11 or 12, wherein the circulation of the second heat transfer composition in the secondary circuit (2) is effected by means of a pump, or by gravity, or by capillarity.

14. Installation according to one of claims 11 to 13, suitable for air conditioning the vehicle interior, and / or heating the vehicle interior, and / or cooling electronic components of the vehicle, and / or heating of electronic components of the vehicle.

15. Installation according to one of claims 11 to 14, wherein the first heat transfer composition comprises one or more heat transfer compounds other than 2,3,3,3-tetrafluoropropene, these compounds preferably being chosen. among the difluoromethane, pentafluoroethane, 1, 1, 2,2-tetrafluoroethane, 1, 1, 1, 2-tetrafluoroethane, 1, 1-difluoroethane, fluoroethane,

16. Installation according to claim 15, wherein the