System for cooling an object

Abstract

The invention relates to a system (1) for cooling an object (3), the system (1) comprising: - an enclosure (4) inside which a volume is arranged to receive said object (3) at a distance from the bottom (5) of the enclosure (4); - a heat exchanger (11), in particular a condenser, arranged inside the enclosure (4), in particular above said object (3); - at least one plate (50) extending at least partially facing a surface of said object (3) and optionally arranged vertically or substantially vertically, wherein an, in particular dielectric, phase-change material (23) is intended to occupy a free volume inside the enclosure (4), in particular between the bottom (5) of the enclosure (4) and the object (3).

Description

[0001] DESCRIPTION

[0002] TITLE: System for cooling an object.

[0003] The invention relates to a system for cooling an object. The invention also relates to a battery comprising such a system and an object, such as at least one battery module. The invention also relates to a vehicle, in particular a motor vehicle, comprising such a system or such a battery.

[0004] A motor vehicle with an electric or hybrid engine includes a traction and / or propulsion battery. Such a battery comprises modules, each module comprising several electrochemical cells for storing electrical energy. It appears important to cool such cells in order to maximize the battery's range and charging speed, particularly due to the increased thermal power density of such batteries.

[0005] A cooling system is known that uses the circulation of a heat transfer fluid, such as glycolated water. However, this solution has drawbacks. In particular, since water is a good electrical conductor, the system's safety constraints make this solution complex to implement.

[0006] The aim of the invention is to provide a system for cooling an object which overcomes the above drawbacks and improves the known systems of the prior art. In particular, the invention makes it possible to produce a system which is simple and reliable and which allows optimized cooling performance.

[0007] The invention relates to a system for cooling an object, the system comprising:

[0008] - an enclosure inside which a volume is arranged to receive said object at a distance from the bottom of the enclosure;

[0009] - a heat exchanger, in particular a condenser, arranged inside the enclosure, in particular above said object;

[0010] - at least one plate extending at least partially facing a surface of said object and possibly arranged vertically or substantially vertically, in which a phase change material, in particular dielectric, is intended to occupy a free volume inside the enclosure, in particular between the bottom of the enclosure and the object.

[0011] The system may include at least one channel extending vertically or substantially vertically.

[0012] The at least one plate may have a crenellated profile.

[0013] At least one plate may present:

[0014] - a profile capable of ensuring mechanical elasticity to the assembly formed by the object and at least one plate; and / or

[0015] - a thickness between 2 and 5 mm.

[0016] The system may comprise at least one plate arranged facing an external surface of the object, in particular a first plate and a second plate, the first and second plates being respectively arranged facing a first longitudinal external surface of the object and facing a second longitudinal external surface of the object opposite the first longitudinal external surface.

[0017] Said object may comprise at least one battery module comprising at least two electrical energy storage elements, the system comprising at least one plate arranged between two adjacent electrical energy storage elements, in particular in the middle of the module. The system may comprise at least one elongated support arranged inside the enclosure, in particular transversely, between the bottom of the enclosure and the object.

[0018] The system may include at least one movable membrane arranged within the enclosure between a transverse outer surface of the object and the enclosure.

[0019] The invention also relates to a battery comprising a system as defined previously and an object, such as at least one battery module.

[0020] The invention also relates to a vehicle, in particular a motor vehicle, comprising a system as defined previously and / or a battery as defined previously.

[0021] The accompanying drawings represent, by way of example, an embodiment of a system for cooling an object according to the invention.

[0022] Figure 1 is a sectional view along a vertical plane AA showing one embodiment of a system for cooling an object.

[0023] Figure 2 is a sectional view along a horizontal plane BB showing one embodiment of a system for cooling an object.

[0024] Figure 3 is a sectional view along a vertical plane CC showing one embodiment of a system for cooling an object.

[0025] An orthonormal reference frame X, Y, Z is defined in which X denotes the longitudinal direction, Y the transverse direction and Z a vertical or substantially vertical direction. The terms "above", "upper", "top", "lower", "bottom" and "bottom" are defined with reference to the Z axis, oriented from bottom to top. To cool the cells of a battery, particularly for a vehicle, one solution is to immerse the cells in a phase-change dielectric material contained in an enclosure. The dielectric material in the liquid phase in contact with the cells, having a high temperature, evaporates, thus cooling the cells. The dielectric material in the vapor phase is then condensed on a so-called "cold" wall, having a low temperature, and descends into the enclosure. Such a solution makes it possible to cool the top and sides of the cells, by thermal conduction.The heat energy generated inside the cells is transferred to the top and sides of the cooled cells.

[0026] Such a solution allows for heat exchange between the cells and the high-performance phase-change dielectric material. As a result, the conduction thermal resistance inside the cells is predominant in the total thermal resistance of the system, which is the sum of the conduction thermal resistance inside the cells and the exchange thermal resistance between the dielectric material and the walls.

[0027] In order to improve the cooling performance of such a system, the applicant sought to reduce the thermal conduction resistance inside the cells.

[0028] The invention proposes not only to cool the top and the two flanks or sides of cells, but also the bottom of the cells or the lower surface of the cells. Usually, the lower surface of the cells is in contact with the bottom of the enclosure, which does not allow the lower surface of the cells to be cooled. The invention proposes a system for cooling the four lateral surfaces of an object, in particular over the entire thickness of the object, and the lower surface of the object. An embodiment of a system 1 for cooling an object 3 is described below with reference to Figures 1 to 3.

[0029] The object 3 may comprise at least one battery module, in particular for a vehicle 100. The at least one battery module may be of the Li-Ion type.

[0030] The vehicle 100 is for example a motor vehicle, in particular with an electric or hybrid engine. The vehicle 100 may be a motor vehicle comprising a thermal engine equipped with a battery, in particular with a voltage of the order of 48 V.

[0031] The system 1 comprises an enclosure 4 inside which a volume is arranged to receive said object 3. The enclosure 4 comprises a base 5.

[0032] The enclosure 4 is for example parallelepipedal or substantially parallelepipedal. The enclosure 4 may comprise a first longitudinal wall 4a and a second longitudinal wall 4b. The first longitudinal wall 4a and the second longitudinal wall 4b are opposite and parallel, or substantially parallel, to each other. The first longitudinal wall 4a and the second longitudinal wall 4b are for example vertical or substantially vertical.

[0033] In the case where the enclosure 4 is parallelepipedal or substantially parallelepipedal, the enclosure 4 may comprise a third side wall 4c and a fourth side wall 4d. The third side wall 4c and the fourth side wall 4d are opposite and parallel, or substantially parallel, to each other. The third side wall 4c and the fourth side wall 4d are for example vertical or substantially vertical. Preferably, the first longitudinal wall 4a and the second longitudinal wall 4b and the third side wall 4c and the fourth side wall 4d and the bottom 5 form a sort of parallelepipedal or substantially parallelepipedal box open on the top (without an upper wall).

[0034] In the case of a parallelepiped enclosure 4, the section AA is made along a plane parallel or substantially parallel to the longitudinal walls 4a, 4b. Still in the case of a parallelepiped enclosure 4, the section BB is made along a plane parallel or substantially parallel to the bottom 5 of the enclosure 4. Still in the case of a parallelepiped enclosure 4, the section CC is made along a plane parallel or substantially parallel to the side walls 4c, 4d.

[0035] The object 3 is intended to be arranged inside the enclosure 4 at a distance from the bottom 5 of the enclosure 4.

[0036] Advantageously, the enclosure 4 comprises a cover 16, in particular a removable cover. The cover 16 is intended to be arranged on top of the enclosure 4 so as to close the enclosure 4 from above.

[0037] A phase-change material 23, in particular dielectric, is intended to occupy a free volume inside the enclosure 4, in particular between the bottom 5 of the enclosure 4 and the object 3.

[0038] Material 23 is for example a material having a boiling temperature of the order of 34°C.

[0039] The material 23 is for example a pure material. Alternatively, the material 23 may be an oil-based mixture. The material 23 is capable of changing from a liquid phase to a vapor phase, and vice versa, depending on temperature and / or pressure conditions. Preferably, the material 23 is dielectric.

[0040] The at least one battery module may comprise at least one electrical energy storage element 6, in particular at least one electrochemical cell.

[0041] The at least one electrical energy storage element 6 is in particular immersed in the material 23.

[0042] The at least one electrical energy storage element 6 is for example a pouch-type electrochemical cell.

[0043] The at least one electrical energy storage element 6 comprises a main part 7, in particular of rectangular shape, where the electrical storage materials are located. The at least one electrical energy storage element 6 further comprises a positive electrical connection and a negative electrical connection 8, 9.

[0044] By height H of the object 3 or of the at least one electrical energy storage element 6, we mean the dimension of the object 3 or of the main part 7 in the Z direction. By width W of the object 3 or of the at least one electrical energy storage element 6, we mean the dimension of the object 3 or of the main part 7 in the X direction.

[0045] As an example of the order of magnitude of dimensions, the height H of the at least one electrical energy storage element 6 is for example between 80 mm and 100 mm.

[0046] Each electrical energy storage element 6 comprises a first main face 7a and a second main face 7b. The first face 7a and the second face 7b are opposite and parallel, or substantially parallel, to each other. The electrical energy storage elements 6 are arranged within the enclosure 4 such that the first face 7a of each electrical energy storage element 6 is located opposite the first longitudinal wall 4a of the enclosure 4 and such that the second face 7b of each electrical energy storage element 6 is located opposite the second longitudinal wall 4b of the enclosure 4.

[0047] Advantageously, the main part 7 of each electrical energy storage element 6 is parallelepipedal. Preferably, all the electrical energy storage elements 6 have identical or substantially identical dimensions and are arranged side by side.

[0048] The electrical energy storage elements 6 are in particular arranged vertically, their main faces in contact with each other.

[0049] The system 1 may comprise at least one support 30 of elongated shape arranged inside the enclosure 4, in particular transversely, between the bottom 5 of the enclosure 4 and the object 3. Advantageously, the system 1 may comprise several supports 30 of elongated shape. The supports 30 of elongated shape may be arranged at a distance from each other in the direction X.

[0050] The at least one elongated support 30 is in particular arranged in the Y direction.

[0051] The at least one elongated support 30 is, for example, a crosspiece.

[0052] The at least one elongated support 30 is for example made of plastic. The at least one elongated support 30 can be placed on the bottom 5 of the enclosure 4. The object 3, in particular the electrical energy storage elements 6, can be placed on the at least one elongated support 30.

[0053] Thanks to the at least one elongated support 30, the main part 7 of the electrical energy storage elements 6 is raised relative to the bottom 5 of the enclosure 4. The electrical energy storage elements 6 are thus brought closer to the condenser 11.

[0054] The at least one elongated support 30 allows the phase change material 23 to pass between the lower surface 3c of the object 3 and the bottom 5 of the enclosure 4.

[0055] The material 23 occupies, fills, a volume V available below and above and / or around the object 3. The material 23 occupies, fills, a volume V available below and above the electrical energy storage elements 6 and / or around the electrical energy storage elements 6. The volume V extends in particular under the electrical energy storage elements 6, that is to say between the bottom 5 of the enclosure 4 and the electrical energy storage elements 6.

[0056] Each electrical energy storage element 6 comprises a lower surface 7c and an upper surface 7d.

[0057] Height e is the distance between the bottom 5 of the enclosure 4 and the lower surface 7c of the electrical energy storage elements 6.

[0058] The height e corresponds for example to 15% of the height H.

[0059] The system 1 may comprise a heat exchanger 11, in particular a condenser. The condenser 11 may be arranged inside the enclosure 4, preferably in the upper part of the enclosure 4, for example above said object 3, in particular just above the electrical energy storage elements 6.

[0060] Advantageously, the condenser 11 may comprise fins.

[0061] Preferably, one or more conduits or pipes 12 may extend within the condenser 11. Such conduits 12 allow the circulation of a liquid, for example a liquid intended to cool the condenser 11, for example a liquid containing water. The system 1 may comprise an inlet / outlet 13 for at least one liquid.

[0062] The system 1 may comprise an openwork separation means 14, in particular a grid or substantially a grid. The openwork separation means 14 may be arranged between the object 3 and the condenser 11, in particular between the upper surface 7d of the electrical energy storage elements 6 and the condenser 11. The openwork separation means 14 comprises in particular walls extending vertically or substantially vertically, advantageously over the entire thickness of the openwork separation means. Thus, the walls create orifices between them so as to allow the phase-change material 23 to pass from the upper surface 7d of the electrical energy storage elements 6 to the condenser 11 and vice versa. The openwork separation means 14 is in particular intended to reduce the height of the system 1 to keep phase-change fluid 23 even in cases where the vehicle would be at significant inclinations.The openwork separating means 14 is, on the other hand, made as thin as possible to reduce the total size of the system 1, the condenser 11 being able to be brought as close as possible to the electrical energy storage elements 6, only the openwork separating means 14 being interposed between the upper surface 7d of the electrical energy storage elements 6 and the condenser 11. A minimum spacing will be chosen between the upper surface 7d of the electrical energy storage elements 6 and the condenser 11, in particular to ensure correct boiling of the phase-change material 23. The gap between the cover 16 and the upper surface 7d of the electrical energy storage elements 6 is in particular chosen so as to guarantee sufficient space for the condenser 11. The gap between the cover 16 and the upper surface 7d of the electrical energy storage elements 6 is for example of the order of 10 mm.

[0063] By thickness of the openwork separating means 14, we mean its dimension in the Z direction.

[0064] The openwork separating means 14 has, for example, a thickness of between 0.5 mm and 5 mm, in particular of between 1 mm and 3 mm.

[0065] The system 1 may comprise at least one membrane 43, 44, in particular mobile, arranged inside the enclosure 4 between a transverse external surface of the object 3 and the enclosure 4.

[0066] The enclosure 4 may comprise three zones: a central zone 40 and first and second end zones 41 and 42 at opposite ends of the enclosure 4 in the direction X. The separation between the central zone 40 and the first end zone 41 may be achieved by a first membrane 43. The separation between the central zone 40 and the second end zone 42 may be achieved by a second membrane 44. Advantageously, the first membrane 43 is mobile. Advantageously, the second membrane 44 is mobile.

[0067] The movable membranes 43, 44 make it possible to obtain a variable volume for the first and second end zones 41, 42, which makes it possible to minimize the volume of phase change material 23, and compensate for the variation in the volume of the cooling fluid.

[0068] The movable membranes 43, 44 are intended to stabilize the pressure in the enclosure 4.

[0069] The transformation of the liquid into vapor increases the volume occupied by the phase change material 23. The two membranes 43 and 44 move towards the side walls 4c and 4d respectively of the enclosure 4. The pressure in the central zone 40 of the boiling enclosure 4 remains at atmospheric pressure. The movable membranes 43 and 44 make it possible to maintain a pressure equal or substantially equal to atmospheric pressure during operation of the system 1.

[0070] The system 1 may comprise at least one opening 10 arranged at a location of at least one of the side walls 4c, 4d of the enclosure 4. The system 1 may comprise an opening 10 arranged at a location of the third side wall 4c and an opening 10 arranged at a location of the fourth side wall 4d. The at least one opening 10 is intended to allow an inlet of outside air into the enclosure 4 when the volume of the dielectric fluid decreases, and an outlet of the air to the outside when this volume increases. The openings 10 are intended to allow an inlet or an outlet of air in the end zones 41 and 42 of the enclosure 4. The at least one opening 10 is intended to guarantee a constant or substantially constant pressure in the enclosure 4, in particular equal or substantially equal to atmospheric pressure. The boiling of the phase change material 23 can thus be carried out at atmospheric pressure.

[0071] The system 1 may comprise a hole made at a location of the cover 16, intended for filling the enclosure 4 with the material 23. The hole is intended to be closed by a closing plug 17. The system 1 may comprise a first overall electrical connection 15 and a second overall electrical connection 19.

[0072] The system 1 comprises at least one plate 50 extending at least partially facing a surface of said object 3.

[0073] The at least one plate 50 is arranged optionally vertically or substantially vertically.

[0074] Advantageously, the at least one plate 50 can extend over the entire height H of said object 3.

[0075] Advantageously, the at least one plate 50 can extend over the entire width W of said object 3.

[0076] The at least one plate 50 is configured to allow the vapors of the phase change material 23 to rise.

[0077] The phase change material 23 is intended to descend inside the enclosure 4 when it is in liquid form, and to rise inside the enclosure 4 when it is in vapor form.

[0078] The at least one plate 50 makes it possible to facilitate the descent of the material 23 in the liquid phase and / or the rise of the material 23 in the vapor phase.

[0079] The at least one plate 50 may comprise at least one channel extending vertically or substantially vertically. The at least one plate 50 may comprise several channels, in particular vertical channels. The at least one plate 50 may be a solid plate pierced with vertical channels. The at least one vertical channel of the at least one plate 50 allows the vapor of the material 23 created on the lower surface 7c of the at least one electrical energy storage element 6 to rise towards the condenser 11, and / or the liquid of the material 23 formed by condensation to descend, thus ensuring the cooling of the bottom of the at least one electrical energy storage element 6.

[0080] The at least one plate 50 may have a crenellated profile, in particular a rectangular profile. The at least one plate 50 may be made from a thin plate folded into a rectangular profile shape.

[0081] The rectangular profile of the at least one plate 50 is intended to optimize the passage of vapors of the phase change material 23, by increasing the surface area of ​​the at least one plate 50 compared to a flat plate.

[0082] The at least one plate 50 is for example made of aluminum or steel. The at least one plate 50 may be made of plastic.

[0083] For the at least one plate 50, one or more materials will be chosen which allow expansion of the object 3 or of the at least one energy storage element 6.

[0084] The at least one plate 50 may have a thickness of between 2 and 5 mm. By thickness of the at least one plate 50 is meant the distance between the main vertical or substantially vertical surfaces of the at least one plate 50.

[0085] The at least one plate 50 makes it possible to compress the at least one energy storage element 6. The at least one plate 50 may have the function of ensuring mechanical elasticity to the object 3, in particular in the case where the energy storage elements 6 swell during operation of the system 1. The shape of the profile of the at least one plate 50 may be chosen to meet this need for mechanical elasticity.

[0086] The at least one plate 50 may have a profile capable of ensuring mechanical elasticity to the assembly formed by the object 3 and the at least one plate 50.

[0087] The system 1 may comprise at least one plate 50 arranged facing an external surface of the object 3.

[0088] The system 1 may comprise a first plate 51 and a second plate 52.

[0089] The first plate 51 may be arranged facing a first longitudinal external surface 3a of the object 3. The second plate 52 may be arranged facing a second longitudinal external surface 3b of the object 3 opposite the first longitudinal external surface 3a.

[0090] In the case where the object 3 comprises at least one battery module comprising at least two electrical energy storage elements 6, the system 1 may comprise at least one plate 50 arranged facing one of the two peripheral electrical energy storage elements 6 of the module, in particular against a first main face 7a and / or against a second main face 7b of an electrical energy storage element 6. The system 1 may comprise two plates 51, 52 arranged respectively facing the two peripheral electrical energy storage elements 6 of the module. The system 1 may comprise at least one plate 53 arranged between two adjacent electrical energy storage elements 6, in particular in the middle of the module, between a first main face 7a and a second main face 7b of two adjacent electrical energy storage elements 6.

[0091] System 1 may comprise three plates 51, 52, 53.

[0092] The material 23 in the vapor phase rises naturally inside the enclosure 4. The material 23 in the liquid phase descends naturally inside the enclosure 4. During a change of liquid-gas state of the material 23, the volume of the material 23 increases. The movable membranes 43, 44 make it possible to achieve volume compensation.

[0093] A system 1 of the type described above makes it possible to cool the bottom of the object 3, in particular the bottom of the at least one electrical energy storage element 6. All sides of the object 3 can thus be cooled by the boiling of the phase change material 23.

[0094] If system 1 allowed only the top and the two vertical sides of the object 3 to be cooled, the maximum temperature of the at least one energy storage element 6 would be at the bottom and in the middle of the at least one energy storage element 6. By also cooling the bottom of the object 3, a system 1 of the type described above makes it possible to divide by four the difference between this maximum temperature and the minimum temperature which is at the surface of the object 3 in contact with the phase change material 23.

[0095] An advantage of a system 1 of the type described above lies in the fact that it makes it possible to increase the cooling performance of the object 3, in particular of the at least one energy storage element 6. This results in the possibility of carrying out ultra-rapid charging of a battery comprising the at least one energy storage element 6. Such a system 1 makes it possible to avoid thermal runaway of a battery. The direct contact between the at least one energy storage element 6 and the phase-change material 23 increases the cooling performance of the system 1.

[0096] A system 1 of the type described above makes it possible to divide the thermal conduction resistance by four compared to a system cooling an object only from above. Indeed, on the one hand the heat path length from the at least one energy storage element 6 to the material 23 is divided by two, on the other hand the heat has two paths to be evacuated to the material 23 instead of a single path when cooling only from above. It is thus possible to significantly reduce the overall thermal resistance of such a system 1.

[0097] The number of plates 50 can be varied according to the number of electrical energy storage elements 6 in a module.

[0098] In a system 1 of the type described above, the higher the number of plates 50, the more homogeneous the cooling will be.

[0099] A system 1 of the type described above may comprise a single plate 50 in the middle of energy storage elements 6, or two plates on each periphery of the module, or even three plates as illustrated in FIG. 2 if the number of energy storage elements 6 is high. Any other number of plates 50 may be chosen.

[0100] Although the invention has been described in the case of a battery for a vehicle, the invention can be applied to a battery intended to be stationary or within an electricity production plant.

[0101] Although the invention has been described in the case of a battery for a motor vehicle, the invention can be applied to a battery intended to equip any type of vehicle, such as agricultural vehicles, construction machinery, or even two-wheeled, three-wheeled or quad-type vehicles, or even airplanes.

[0102] Although the invention has been described in the case of pouch-type electrochemical electrical energy storage cells, the invention applies to any type of cell.

[0103] Although the invention has been described in the case of a battery, the invention applies to any type of object to be cooled, for example to a server.

Claims

CLAIMS 1. System (1) for cooling an object (3), the system (1) comprising: - an enclosure (4) inside which a volume is arranged to receive said object (3) at a distance from the bottom (5) of the enclosure (4); - a heat exchanger (11), in particular a condenser, arranged inside the enclosure (4), in particular above said object (3); - at least one plate (50) extending at least partially facing a surface of said object (3) and possibly arranged vertically or substantially vertically, in which a phase change material (23), in particular dielectric, is intended to occupy a free volume inside the enclosure (4), in particular between the bottom (5) of the enclosure (4) and the object (3).

2. System according to claim 1, wherein the at least one plate (50) comprises at least one channel extending vertically or substantially vertically.

3. System according to claim 1 or 2, in which the at least one plate (50) has a crenellated profile.

4. System according to one of the preceding claims, in which the at least one plate (50) has: - a profile capable of ensuring mechanical elasticity to the assembly formed by the object (3) and the at least one plate (50); and / or - a thickness between 2 and 5 mm.

5. System according to one of the preceding claims, comprising at least one plate (50) arranged facing an external surface of the object (3), in particular a first plate (51) and a second plate (52), the first (51) and second (52) plates being respectively arranged facing a first longitudinal external surface (3a) of the object (3) and facing a second longitudinal external surface (3b) of the object (3) opposite the first longitudinal external surface (3a).

6. System according to one of the preceding claims, wherein said object (3) comprises at least one battery module comprising at least two electrical energy storage elements (6), the system comprising at least one plate (53) arranged between two adjacent electrical energy storage elements (6), in particular in the middle of the module.

7. System according to one of the preceding claims, comprising at least one elongated support (30) arranged inside the enclosure (4), in particular transversely, between the bottom (5) of the enclosure (4) and the object (3).

8. System according to one of the preceding claims, comprising at least one movable membrane (43, 44) arranged inside the enclosure (4) between a transverse external surface of the object (3) and the enclosure (4).

9. Battery comprising a system (1) according to one of the preceding claims and an object (3), such as at least one battery module.

10. Vehicle (100), in particular automobile, comprising a system (1) according to one of claims 1 to 8 and / or a battery according to claim 9.

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