FR3117681A1 - Device for thermal regulation of an electrical and/or electronic element using a dielectric fluid and assembly comprising such a device - Google Patents

Abstract

Device for thermal regulation of an electrical and/or electronic element using a dielectric fluid and assembly comprising such a device The invention relates to a device (4) for regulating the temperature of at least one electrical component and/or or electronic device (2), in particular for a motor vehicle, in particular an energy storage cell, the device (4) comprising an enclosure (6) intended to contain a dielectric fluid and means for spraying the surface of the said component using said dielectric fluid, said means for spraying comprising at least one stirrer (8), said stirrer comprising a vibrating surface (10) intended to vibrate and an actuator connected to this surface to cause it to vibrate, characterized in that the means for spraying are configured to control the agitator (8) so that the vibrating surface vibrates at a frequency between 1.6 and 2.4 MHz. Figure for abstract: Figure 3

Description

Device for thermal regulation of an electrical and/or electronic element using a dielectric fluid and assembly comprising such a device

The invention relates to a device for thermal regulation of an electrical and/or electronic element using a dielectric fluid. The invention also relates to a box comprising said device as well as a plurality of electrical and/or electronic elements and a dielectric fluid.

Electrical and/or electronic elements, whether electrical energy storage cells, integrated circuits, servers, data centers, etc. require thermal regulation in order to maintain them within their operating temperature range.

The invention is in particular intended to equip motor vehicles, in particular motor vehicles with electric or hybrid motorization and to thermally regulate an electrical energy storage cell or power electronic elements.

As the market share of electric vehicles is growing, the dielectric/heating issues of the battery packs fitted to them are becoming strategic issues. The objective is to design the most efficient, efficient and economical battery thermal management device possible.

The invention can also be applied to the thermal regulation of a data center. Data centers around the world currently account for 10% of global electricity consumption. The advent of “blockchain” and 5G technologies means that this percentage could increase drastically in the coming years. At least half of this consumption comes from the cooling systems of these data centers. Currently the majority of data centers are air-cooled by cooling the ambient air of the storage rooms by air conditioning devices. The optimum operating temperature for data centers is between 5°C and 40°C, more specifically around 27°C. Taking into consideration that air has a very low conductivity, in order to sufficiently cool the electronic elements, which can reach temperatures exceeding 60°C, the temperature difference between the air and the electronic elements to be cooled must be important and therefore this type of device is very energy-intensive.

In the automotive field, it is common to meet the need for cooling (and/or heating) of electric batteries to use heat exchangers consisting of a cold plate with circulation of a heat transfer liquid (e.g. mixture of water and ethylene glycol), the plates being in contact with the cells to be cooled. This type of technique can lead to uneven cooling (and/or heating) of the batteries and thus limit their lifespan and performance. These devices also have a high thermal resistance due to the thicknesses of material present between the heat transfer liquid and the cells.

A proposed solution to address this problem consists of immersing the electric batteries in a dielectric heat transfer fluid. This immersion can be carried out with a circulation of fluid or in static condition with phase change.

These two techniques are efficient from a thermal point of view, in particular because of the direct contact established between the liquid and the cells, but have the disadvantage of using a large quantity of dielectric liquid, which increases the cost and weight of the pack. battery and are also sensitive to changes in vehicle attitude during operation.

The invention aims to at least partially solve these technical problems by proposing a device for regulating the temperature of at least one electrical and/or electronic component, the device comprising an enclosure intended to contain a dielectric fluid and means for spraying the surface of said component with the aid of said dielectric fluid, said means for spraying comprising at least one agitator, said agitator comprising a vibrating surface intended to vibrate and an actuator connected to this surface to make it vibrate, the agitator of which is configured to make it vibrate the vibrating surface at a frequency between 1.6 and 2.4 MHz.

In this interval, the agitator is able to tear off micro droplets of dielectric fluid and thus to mist said fluid. The closer we get to 1.6 MHz, the larger the particles will be. Large particles make it possible to have a good flow but a low heat exchange between the surface of the components to be regulated and the fluid, due in particular to a reduction in the exchange surface and a greater thermal inertia.

On the other hand, the closer we get to 2.4 MHz, the finer the particles. Fine particles allow a very good heat exchange between the surface of the components to be cooled and the fluid but have the disadvantage of a low flow rate. It is therefore necessary to have a good heat exchange coefficient to increase the number of stirrers compared to larger particles.

Outside this frequency range, the agitator does not have a vibration frequency that properly mists the fluid, but still allows the fluid to be stirred.

The actuator is generally suitable for vibrating the vibrating surface at a frequency of at least 50kHz and at most 30MHz,

Means for spraying means any type of means making it possible to bring the dielectric fluid into contact with the electrical and/or electronic component(s) other than by immersing the said components in the said dielectric fluid.

These are in particular spray means, projection means or any means capable of producing a circulation of said fluid so as to bring the dielectric fluid into contact with the surface of the components, in the form of a liquid film, jets, droplets from misting or other.

By agitator is meant any means for setting the fluid in motion, particularly in the liquid state, and thus agitating the fluid, for example in particular an ultrasonic agitator.

This device not only makes it possible to recover large quantities of heat and to ensure homogeneous cooling by direct contact of the dielectric fluid and the cells to be cooled, but also makes it possible to limit the quantity of dielectric fluid and therefore the weight and cost of the device in eliminating the dielectric liquid bath known in previous devices.

Indeed, the volume of dielectric fluid in the liquid state can be very low, preferably at most 10% of the volume of the enclosure and preferably at least 2%. The volume of dielectric liquid used is for example between 4 and 15 liters depending on the size of the battery pack. These volumes of dielectric liquid naturally include the volumes introduced into the device in the initial state.

The invention may also include any of the following features, taken individually or in any technically possible combination:

- the stirrer is configured to vibrate the vibrating surface at a frequency between 1.8 and 2.2 MHz. This frequency range is a good compromise making it possible to limit the number of stirrers necessary in order to limit the cost and complexity of the device, while allowing satisfactory heat exchange.

• un premier mode, dit mode de pulvérisation, dans lequel la surface vibrante vibre à une fréquence avantageusement comprise entre 1.6 et 2.4 MHz,
• un deuxième mode, dit mode d’agitation, dans lequel la surface vibrante vibre à une fréquence avantageusement inférieure à 1.6 MHz ou supérieur à 2.4 MHz.

En effet, hors de la plage de fréquence 1.6MHz et 2.4 MHz, la fréquence de vibration n’est pas suffisante pour permettre une pulvérisation du fluide diélectrique, mais en permet l’agitation. La pulvérisation du fluide n’est nécessaire que lors de gros besoins en régulation thermique du composant électrique et/ou électronique. En effet, la pulvérisation permet d’augmenter les performances d’échange thermique entre le fluide diélectrique et le composant à réguler. Par conséquent, le mode de pulvérisation ne sera nécessaire par exemple que lors d’une phase de charge rapide nécessitant un fort refroidissement ou d’un besoin de chauffage rapide de la batterie. Le mode pulvérisation correspond à un mode dans lequel la fréquence utilisée par l’agitateur permet la mise en résonance du fluide afin de pouvoir le pulvériser. A contrario, le mode agitation correspond à un mode dans lequel la fréquence utilisée par l’agitateur ne permet pas, ou bien seulement partiellement, la mise en résonance du fluide.- the means for watering are configured to control the at least one agitator (8) according to two operating modes:

• a first mode, called sputtering mode, in which the vibrating surface vibrates at a frequency advantageously between 1.6 and 2.4 MHz,
• a second mode, called stirring mode, in which the vibrating surface vibrates at a frequency advantageously lower than 1.6 MHz or higher than 2.4 MHz.

Indeed, outside the 1.6 MHz and 2.4 MHz frequency range, the vibration frequency is not sufficient to allow spraying of the dielectric fluid, but allows its agitation. The spraying of the fluid is only necessary when there are major needs for thermal regulation of the electrical and/or electronic component. Indeed, the spraying makes it possible to increase the performance of heat exchange between the dielectric fluid and the component to be regulated. Consequently, the spray mode will only be necessary, for example, during a fast charging phase requiring strong cooling or a need for rapid heating of the battery. The spray mode corresponds to a mode in which the frequency used by the agitator allows the resonance of the fluid in order to be able to spray it. Conversely, the agitation mode corresponds to a mode in which the frequency used by the agitator does not allow, or only partially, the resonance of the fluid.

- the stirrer is of the piezoelectric type.

- the device is configured such that the vibrating surface is at least partially immersed in the dielectric fluid, preferably completely immersed.

- the device comprises a tank under the location of the battery cells, the tank being capable of recovering, in the liquid phase, the dielectric fluid sprayed by the agitator on the surface of the battery cells. The reservoir is the part of the enclosure of the device intended to receive the dielectric fluid. The advantage of the invention is to make it possible not to have to completely immerse the electrical and/or electronic components to be thermally regulated.

- the device comprises a plurality of stirrers, advantageously the stirrer or stirrers are arranged in the tank, preferably in a bottom of the tank and/or on a side wall of the tank.

- at least one stirrer is placed on a side wall of the tank and ensures the stirring mode, at least one stirrer is placed on the bottom of the tank and allows the spraying mode

- the reservoir is adapted to receive part of the at least one electrical and/or electronic component. Advantageously, the electrical and/or electronic components are, after assembly in a device according to the invention, partially immersed in the dielectric fluid;

- the device further comprising a means for heating and/or a means for cooling the dielectric fluid;

- the means for cooling the dielectric fluid comprises a heat exchanger for exchanging heat with the dielectric fluid;

- the means for heating the dielectric fluid comprises a heat exchanger for exchanging heat with the dielectric fluid. Advantageously, the heating means comprises a resistive element, or a heat exchanger suitable for a second hot fluid to pass through, or any other embodiment that a person skilled in the art deems appropriate;

- The dielectric fluid cooling means comprises a heat exchanger located in the reservoir. This mode of cooling is advantageously used when the fluid used is intended to remain in the liquid state over the entire operating temperature range of the device;

- the cooling means comprises a condenser configured so as to condense the dielectric fluid to pass from the vapor phase to the liquid phase and to cause the said fluid to trickle down to the reservoir. This mode of cooling is advantageously used when the fluid used is intended to change state or phase depending on the temperature, called two-phase fluid, then changing phase at an optimum operating temperature of the component to be cooled;

- the reservoir comprises a first and a second opening adapted to be connected to a circulation circuit of the dielectric fluid. The openings are intended to be connected to inlet and outlet pipes for the dielectric fluid and in particular allow the fluidic connection between the reservoir of the device and a remote cooling and/or heating means, in other words external to the device;

- the vibrating surface is a membrane;

- the actuator is of the piezoelectric type;

- the device is configured such that the vibrating surface is at least partially immersed in the dielectric fluid, preferably completely immersed;

- the level of dielectric fluid above the vibrating surface is at least 10mm;

- the diameter of the vibrating surface is at least 5mm and at most 35mm, preferably at least 15mm and preferably at most 25mm;

- the dielectric fluid has the ability to change state or phase depending on the temperature, advantageously the point of change of state is chosen according to the optimum operating temperature of the electrical device to be thermally regulated, the fluid is intended to vaporize at the surface of the cells, and thus to pass from a 100% liquid state to a 100% vapor state by its contact with the surface of the cells;

- the dielectric fluid is chosen so as to remain in the liquid state over the entire range of use of the device;

- the dielectric fluid evolves in a closed enclosure, sealed to said fluid regardless of its state.

- the closed enclosure is delimited by the walls of the device,

- the stirrer is configured so as to spray the dielectric fluid in the form of fine drops, intended to be deposited on the surface of the cells,

- the agitator is under the level of at least one of the battery cells

- several agitators are arranged under the location of several battery cells

- the agitators are distributed over the entire tank

- the agitators are in the bottom of the tank

- the condenser is configured for the circulation of a heat transfer fluid, for example a refrigerant fluid or glycol water, intended to exchange heat with the dielectric fluid;

- the condenser is positioned above the battery cells, preferably the condenser covers a majority of the surface occupied by the cells,

- the condenser is configured for the circulation of a refrigerant fluid intended to exchange heat with the dielectric fluid,

- the condenser forms an upper wall of the battery pack,

- the condenser covers or overhangs a majority, preferably the entire area comprising the battery cells.

- the condenser has a face that is substantially flat and inclined with respect to a horizontal direction, for example when the device is mounted on a motor vehicle,

- the condenser comprises a cooling fluid circuit passing through it in its thickness, advantageously in several passes, so as to evacuate the heat of the condensation of the dielectric fluid in the cooling fluid. The cooling fluid circuit is for example connected to a motor vehicle air conditioning circuit or cooled by the latter.

- the device comprises, in the reservoir, a means for heating the dielectric fluid, so as to heat the cells if necessary.

- The device comprises a first series of at least one stirrer advantageously present on the bottom of the device, and a second series of at least one stirrer advantageously present on the side walls of the device. All stirrers of the same series are jointly controlled

- the first and second series can be activated jointly, or activated selectively.

- only the second series is activated in stirring mode during a stirring step,

- both series are activated in agitation mode.

- during a spray step, the first series is activated in a spray mode.

- during a spraying step, at least one of the two series, for example the first series, is activated in spray mode and the second series is activated in agitation mode.

- both series are activated together in spray mode.

• un moyen de chauffage et/ou refroidissement de fluide diélectrique déporté,

• une conduite d’alimentation et une conduite d’évacuation connectant fluidiquement le dispositif de gestion thermique et le moyen de chauffage et/ou refroidissement.

The invention also relates to a thermal management system for an electrical and/or electronic component comprising a device according to one of the preceding claims, and further comprising:

• a remote dielectric fluid heating and/or cooling means,

• a supply pipe and a discharge pipe fluidically connecting the thermal management device and the heating and/or cooling means.

This system is particularly advantageous when the dielectric fluid used is intended to remain in the liquid state over the entire operating temperature range of the device according to the invention, for example a mineral oil or a fluorinated fluid. Indeed, this makes it possible to provide a device according to the invention that is as compact as possible and to deport the heating and/or cooling means and consequently to deport the size of said heating and/or cooling means.

The advantage of agitators in agitation mode is to allow homogenization of the temperature of the dielectric fluid, in particular when the remote heating and/or cooling means are activated.

By remote heating and/or cooling means is meant a means distinct from the device according to the invention.

In addition, if the dielectric fluid is intended to effect a phase change, which will be called a two-phase dielectric fluid for simplicity, the system of the invention allows for example sub-cooling of the fluid in the liquid phase before spraying on the electrical and/or electronic components and thus improving the cooling capacity.

Advantageously, the system comprises a pump on one of the supply or discharge pipes making it possible to bring the dielectric fluid from the reservoir to the means of heating and/or cooling of the dielectric fluid.

After assembly, with battery cells and a dielectric fluid, the system comprises a battery box comprising a thermal regulation device according to the invention.

The remote dielectric fluid heating and/or cooling means may comprise a first heat exchanger for cooling and a second heat exchanger for heating.

The heating means may alternatively comprise a fluid/fluid type heat exchanger allowing the dielectric fluid to exchange calories with a second fluid from a circuit external to the system.

• détection d’une valeur de besoin en gestion thermique :

• si la valeur est inférieur à une première valeur seuil, aucune activation de l’agitateur,
• si la valeur est comprise entre la première valeur seuil, et une deuxième valeur seuil, supérieure à la première valeur, passage à une étape d’agitation, activation du mode d’agitation d’au moins un agitateur
• si la valeur est supérieure à la deuxième valeur seuil, passage à une étape de pulvérisation, activation du mode de pulvérisation d’au moins un agitateur.

The invention also relates to a method for thermal management of a device as described in the preceding claims, comprising the following steps:

• detection of a thermal management requirement value:

• if the value is lower than a first threshold value, no activation of the stirrer,
• if the value is between the first threshold value, and a second threshold value, greater than the first value, passage to a stirring step, activation of the stirring mode of at least one stirrer
• if the value is greater than the second threshold value, going to a spraying step, activating the spraying mode of at least one stirrer.

There are several methods well known to those skilled in the art for detecting a need for thermal management, namely cooling or heating, of an electrical and/or electronic component. For example, for a component of the battery cell type for an electric vehicle, the value justifying the need for cooling or heating could be the surface temperature of the cells, the temperature of the dielectric fluid, the internal pressure of the device, the outside temperature a signal given by an on-board computer of said vehicle with a view to preparing for a rapid charging phase, for example for connection to a terminal of the rapid charging type, or a rapid acceleration phase.

For a device comprising a first series of stirrers present on the bottom of the device, and a second series of stirrers present on the side walls of the device, each series can be controlled independently of the other.

During a stirring step, only a first series, advantageously the second series, can be activated in stirring mode. In the case of a large device, or a strong need for agitation, both series can be activated in agitation mode.

During a spraying step, at least one of the two series, for example the first series, is activated in spray mode and the second series is not activated, or is activated in agitation mode.

Thermal management, to understand the heat exchange capacity, will be optimal when a first series is activated in spraying mode, the other series activated in agitation mode. The agitation allows homogenization of the fluid before spraying and thus being optimal in particular if one of the heating and/or cooling means, namely of the device or remote, is activated.

Both series can also be activated together in spray mode.

For the application of the method, the spray mode may correspond to a frequency range of vibration of the agitator different from that described above for the device.

Spray mode is then understood to mean for the implementation of the method a range of vibration frequency of the agitator corresponding to the resonance mode of the dielectric fluid used in the method. The method can therefore also comprise a step of adjusting the spraying and stirring modes of the stirrer as a function of the resonance frequency of the dielectric fluid used. As a general rule, the resonance frequency, as a function of the temperature of the fluid, is known data and supplied by the manufacturer of the dielectric fluid.

The invention also relates to the use of a device according to the invention in which the vibrating surface of the stirrer vibrates according to a frequency range between 1.6 and 2.4 MHz, advantageously between 1.8 and 2.2 MHz.

The invention also relates to a box comprising the device (1) according to one of the preceding claims, further comprising a plurality of battery cells and a dielectric fluid arranged in the enclosure of said device.

- the volume of dielectric fluid in the liquid state is at most 50% of the volume of the enclosure, preferably at most 25%, preferably at most 10%, preferably at most 6% , preferably at most 4% and preferably at least 2%, of the total volume of the dielectric enclosure in which the battery cells are housed;

- the dielectric fluid has the ability to change state or phase depending on the temperature, advantageously the point of change of state is chosen according to the optimum operating temperature of the electrical device to be thermally regulated, the fluid is intended to vaporize at the surface of the cells, and thus to pass from a 100% liquid state to a 100% vapor state by its contact with the surface of the cells;

- the dielectric fluid is chosen so as to remain in the liquid state over the entire range of use of the device.

The invention will be better understood and other details, characteristics and advantages of the invention will appear on reading the following description given by way of non-limiting example and with reference to the appended drawings in which:

- the is a partial perspective side view of a battery case provided with battery cells and a thermal management device according to one embodiment of the invention;

- the , is a partial sectional view of the battery pack of the ,

- the is a schematic view of a system according to the present invention.

The illustrates a battery box 1 comprising a plurality of battery cells 2 and a device 4 for regulating the temperature of the battery cells 2. The set of battery cells 2 forms what is called the “battery”. The battery here comprises nine cells but this is only a schematic example and the battery may comprise a much larger number of cells, which may or may not be mechanically and/or electrically assembled into a module.

For their correct operation, it is desired that the temperature of the cells 2 be maintained within a restricted range of values, for example between 20° C. and 40° C. The device 4 illustrated has precisely the function of carrying out such temperature regulation.

The device 4 comprises an enclosure 6 in which the cells 2 are housed as well as stirrers 8 for spraying a dielectric fluid (not shown) as far as the surface of the cells 2. The enclosure 6 is delimited by the walls of the device 4. The enclosure 6 is closed so that the dielectric fluid circulates and remains within it. It has a shape of any suitable type.

In the embodiment represented, the dielectric fluid is deposited on the surface of the cells in the liquid state and evaporates on contact with the surface of the cells 2, thus cooling the cells 2 by absorption of heat in the dielectric fluid. In an embodiment in which the fluid would be intended to remain in the liquid state over the entire range of use, the fluid is deposited on the surface of the cells in the liquid state and flows by gravity until falling in tank 12.

Once evaporated, the dielectric fluid rises by natural convection to a condenser intended to cool and condense the dielectric fluid from the vapor state to the liquid state by evacuating its heat. The dielectric fluid then returns by streaming by gravity to a reservoir 12 of dielectric fluid, in the bottom of the device. Agitators 8 are housed in the bottom of tank 12.

The stirrers 8 described are three in number, but their number is of any suitable type.

In the example illustrated, the three agitators 8 are each housed in the middle of three longitudinal sections of the tank 12, and, in general, the agitators 8 are preferably distributed over the whole of the tank 12.

Each stirrer 8 comprises a membrane 10 intended to vibrate, forming a vibrating surface, and an actuator (not shown) connected to this vibrating surface to make it vibrate and thus spray the dielectric fluid in which each stirrer 8 is immersed.

The membrane 10 is of any suitable type.

The stirrer 8 is thus suitable for stirring the dielectric fluid in the liquid state and spraying it up to the surface of the battery cells.

The vibrating surface of each stirrer 8 is immersed in at least 10 mm of dielectric fluid in the liquid state. The volume of dielectric fluid in the cooling enclosure is chosen so as to have these levels of dielectric fluid in the reservoir, above each stirrer 8.

The used volume of liquid is for example between 5 and 10 liters depending on the size of the battery box. In general, the volume of dielectric liquid is at most 50%, advantageously at most 25%, preferably at most 10%, preferably at most 6% of the volume of the enclosure , preferably at most 4% and preferably at least 2%.

More generally, the thermal regulation device is configured such that the vibrating surface is at least partially immersed in the dielectric fluid, preferably completely immersed.

The vibrating surface has a diameter of at least 5mm and at most 35mm, preferably at least 15mm and preferably at most 25mm.

As seen more particularly on the , the dielectric fluid reservoir is formed in part by a recess in the device, under the battery cells.

Reservoir 12 is under the location of battery cells, and thus being able to recover, in liquid phase, the dielectric fluid sprayed by the agitator onto the surface of the battery cells. advantageously the tank also extends over part of the height of the cells, as visible on the .

In the example illustrated, the device 4 comprises in its bottom support feet 14 on the periphery and the center of the device 4.

The device 4 also comprises longitudinal elongated support rails 16 extending over substantially the entire length of the battery pack. Only one of the two rails 16 is visible in the figures. The 16 rails are parallel and spaced approximately the width of the 2 battery cells. These rails 16 are described for purely illustrative and non-limiting purposes. In general, the cells 2 are held at the height of the bottom in the device by means of any suitable type.

These rails emerge above the coolant level, but alternatively the battery cells are bathed in the dielectric liquid.

Each stirrer 8 is arranged in the bottom of the tank, under the battery cells.

In the example illustrated, the stirrers 8 are aligned and located in a median plane in the direction transverse to the direction of alignment of the cells, that is to say substantially in the middle of the cells.

In general, the arrangement and the number of stirrers are of any suitable type.

In the upper part of the device 4, is illustrated the condenser 18 for the dielectric fluid, that is to say intended to condense the dielectric fluid and a lid 20 closing the enclosure 6.

As visible in Figures 1 and 2, the condenser 18 comprises a cooling fluid circuit 22 passing through its thickness in several passes, so as to evacuate the heat from the condensation of the dielectric fluid in the cooling fluid. The cooling fluid circuit 22 is for example connected to a motor vehicle air conditioning circuit or cooled by the latter.

The condenser 18 is positioned above the battery cells 2. Preferably, the condenser 18 covers a majority of the surface occupied by the cells.

The condenser 18 indirectly cools the battery cells 2 by capturing the vapor of dielectric fluid resulting from the evaporation of this fluid in contact with the surface of the cells and by condensing it. With this arrangement of the condenser, the dielectric fluid vapor is naturally guided towards the condenser by an upward convection movement.

The condenser 18 forms with the lid the upper wall of the battery pack.

The condenser 18 has a face that is substantially flat and inclined with respect to a horizontal direction when the battery pack is mounted on a motor vehicle. Alternatively, the condenser has several inclined surfaces.

In general, the lower surface of the condenser is configured to guide the flow of liquid dielectric fluid towards the reservoir of dielectric fluid in the liquid state, the condenser comprises a condensation surface comprising a hydrophobic material, for example silicone, Teflon, wax or fatty acids. In general, this hydrophobic material can also be used on dielectric fluid condensers for which the system for spraying the batteries with dielectric fluid would be different, for example spray systems.

Finally, the device comprises, in the reservoir, a means for heating the dielectric fluid, so as to heat the cells if necessary.

It should be noted that the 24 observation windows are those of a prototype and that these 24 windows are intended to be removed in a series version.

The shows an alternative embodiment to Figures 1 and 2. Only the different aspects of the embodiment shown in and 2 will be discussed here. In addition, a thermal regulation device as presented in Figures 1 and 2 is quite suitable for integration into the system presented in Figures 1 and 2. .

The system presented in comprises a battery box 1 comprising a device 4 for thermal regulation.

The device comprises a first series of stirrers 8 present on the bottom 12 of the device, and a second series of stirrers 8 present on the side walls of the device. Advantageously, the first and second series can be activated jointly, in spray mode as shown in the , or selectively activated. For example, only the second series is activated in stir mode during a stir step. In a spray mode, the first series is activated in a spray mode while the second series can be activated in an agitation mode.

Fluid level 11 is sufficient to allow cells 2 to be partially immersed.

Reservoir 12 comprises a first 21 and a second 22 opening adapted to be connected to a dielectric fluid circulation circuit. The openings are connected to inlet 23 and outlet 24 conduits for the dielectric fluid and allow in particular the fluidic connection between the reservoir of the device and a remote cooling and/or heating means 15, in other words external to the device.

Claims (10)

Device (4) for regulating the temperature of at least one electrical and/or electronic component (2), in particular for a motor vehicle, in particular an energy storage cell, the device (4) comprising an enclosure (6) intended to containing a dielectric fluid and means for wetting the surface of said component with said dielectric fluid, said means for wetting comprising at least one stirrer (8), said stirrer comprising a vibrating surface (10) intended to vibrate and an actuator connected to this surface to make it vibrate, characterized in that the means for spraying are configured to control the agitator (8) so that the vibrating surface vibrates at a frequency comprised between 1.6 and 2.4 MHz. Device (1) according to the preceding claim, in which the stirrer (8) is configured to cause the vibrating surface to vibrate at a frequency comprised between 1.8 and 2.2 MHz. Device according to one of the preceding claims, in which the means for watering are configured to control the at least one stirrer (8) according to two operating modes:

• a first mode, called spray mode, in which the vibrating surface (10) vibrates at a frequency between 1.6 and 2.4 MHz,
• a second mode, called stirring mode, in which the vibrating surface (10) vibrates at a frequency lower than 1.6 MHz or higher than 2.4 MHz

Device (1) according to any one of the preceding claims, in which the device is configured such that the vibrating surface (10) is at least partially immersed in the dielectric fluid, preferably totally immersed. Device (1) according to any one of the preceding claims, in which the device (4) comprises a reservoir (12) under the location of the battery cells, the reservoir (12) being capable of recovering, in the liquid phase, the dielectric fluid sprayed by the agitator (8) onto the surface of the battery cells and in which the agitator(s) (8) are arranged in the reservoir (12), preferably in a bottom of the reservoir and/or on a side wall of the reservoir. Device according to one of the preceding claims further comprising a means for heating and/or a means for cooling the dielectric fluid. System for thermal management of an electrical and/or electronic component comprising a device according to one of the preceding claims, and further comprising:

• a remote dielectric fluid heating and/or cooling means,

• a supply line and a discharge line fluidly connecting the thermal management device and the heating and/or cooling means.

Method for thermal management of a device as described in the preceding claims comprising the following steps:

• detection of a thermal management requirement value:

• if the value is lower than a first threshold value, no activation of the stirrer,
• if the value is between the first threshold value, and a second threshold value, greater than the first value, passage to a stirring step, activation of the stirring mode of at least one stirrer
• if the value is greater than the second threshold value, going to a spraying step, activating the spraying mode of at least one stirrer.

Use of a device according to one of claims XX to XX in which the vibrating surface of the stirrer vibrates according to a frequency range between 1.6 and 2.4 MHz, advantageously between 1.8 and 2.2 MHz. Box comprising the device (1) according to one of the preceding claims, and further comprising a plurality of electrical and/or electronic components and a dielectric fluid arranged in the enclosure of the said device.