The invention relates to a thermal regulation device intended in particular for providing the cooling and/or the heating of a battery of an automobile.
Automobiles, in particular electric or hybrid vehicles the propulsion of which is provided at least partially by an electric motor, are equipped with a battery including a plurality of cells arranged in series and/or in parallel in a protective casing in order to form a battery or an assembly called a battery pack.
Charging and discharging a battery are exothermic processes. However, in the case of an excessively high temperature, ageing reactions are accelerated and the result may be a reduction in the service life of the battery. There is also a risk of thermal runaway that may go as far as destruction of the battery. On the other hand, in the case of an excessively low temperature, i.e. below a predefined minimum threshold, the capacity of the battery may greatly decrease.
It is therefore important to monitor and ensure thermal management of the battery.
Currently the batteries of electric and hybrid vehicles are cooled by means of active systems of various natures.
It may be a case of circulation of air in natural or forced convection, circulation of glycated water or of oil, or the evaporation of a refrigerating fluid.
When it is a case of oil or air in particular, the fluid may be in direct contact with the cells of the battery. Such cooling is termed direct cooling.
In a variant, the fluid may pass over cooling surfaces, for example through a closed circuit including a cooling loop equipped with cooling plates forming heat exchangers. Such cooling is termed indirect cooling.
In the case of indirect cooling, it is necessary to maximize the contact surfaces between the heat exchangers and the battery and to limit the contact resistances in order to avoid overheating of the cells degrading the service life and performances thereof. In order to minimize the contact resistances, battery manufacturers generally have recourse to the use of thermal interface materials of the film or pad type, or thermal paste.
Fitting these elements is often complex and expensive and may require a great deal of time when the battery pack is assembled.
The invention aims to remedy the aforementioned problems, in a simple, reliable and inexpensive manner.
For this purpose, the invention relates to a thermal regulation device including a member to be heated or to be cooled, a fluid-circulation conduit comprising at least one flexible part able to deform according to the pressure of the fluid within the conduit, and at least one contact zone coming into contact with said member when the pressure of the fluid in the conduit is higher than a given pressure and which is moved away from said member when the pressure of the fluid in the conduit is below the given pressure, the thermal regulation device including regulation means able to vary the pressure of the fluid in the conduit.
In this way, it is possible to cool or heat the member when the conduit is in contact with said member. Moreover, it is possible to stop or reduce the cooling or the heating of the member when they contact zone is separated from said member. The movement of the contact zone is obtained by deforming the flexible part, by adapting, during the operation of the thermal regulation device, the pressure of the fluid within the conduit, using regulation means.
These features make it possible in particular:
Returning the contact zone into the separated position can be provided by the intrinsic elasticity of the flexible part, by the addition of additional return means, or by applying a negative pressure in the conduit so as to suck the fluid contained in the conduit, at least partly, and thus to separate the contact zone from the member to be heated or to be cooled.
Applying a negative pressure is particularly useful in the case of mounting or dismantling such a device.
The contact zone may be formed, at least partly, by the flexible part.
The ratio between the contact surface between the conduit and the member to be heated when the pressure of the fluid is below the given pressure, and the contact surface between the conduit and the member to be heated when the pressure of the fluid is above the given pressure, may be between 0 and 1, preferably between 0 and 0.5.
The fluid may be a heat-transfer fluid, for example glycated water, or a refrigerating fluid.
The contact between the conduit and the member may be direct or indirect, i.e. implemented by means of an additional element or of an interface layer.
The flexible part may be produced from elastomer or from thermoplastic or metal material, or by a combination of materials, at least in part.
The elastomer material is for example of the rubber type.
The thermoplastic material is for example of the TPV type.
The elastomer or thermoplastic material may be loaded, at least in one zone of the conduit, by means of a thermally conductive filler, for example graphite, in order to improve the heat exchanges between the fluid and the member.
In a variant, the filler may be a flame-retardant material or an electrical insulator, or a combination of the aforementioned fillers.
At least a part of the conduit may include a composite material, a thermoplastic material or a thermosetting material, or a combination of these materials.
The flexible part may include at least one wall including at least one zone inclined with respect to the direction of the movement of the contact zone.
The contact zone moves for example in translation along an axis perpendicular to the member in the zone intended to come into contact with the conduit. A translation along the axis of the wall in the contact zone could also be envisaged.
Adapting the pressure in the conduit can also make it possible to vary the contact surface between the conduit and the element or elements to be cooled or to be heated. In this case, the higher the pressure in the conduit, the more extensive will be the contact zone, so as to favor the heat exchanges. Conversely, the lower the pressure in the conduit, the smaller will be the contact zone, or even zero, so as to limit the heat exchanges.
Said wall may include a plurality of successive inclined zones, oriented in different directions.
The flexible zone may thus have the general form of a bellows able to deform.
The contact zone may include at least one metal part.
Such a metal part makes it possible to favor the heat exchanges.
Said metal part may be intended to come into contact with the fluid in the conduit and with the member.
In a variant, the metal part may be embedded in the thickness of the conduit.
The device may include a support part, the conduit being formed partly or bearing on said support part, opposite the contact zone.
The support part may be a casing element of an electric battery of an automobile.
The support part may be a crossmember or a longitudinal member. The crossmember or the longitudinal member may be produced from a composite or metal material. The composite material may include reinforcement fibers embedded in a polymer matrix.
The support part may be a material consisting of a set of plies superimposed on one another, the conduit being delimited at least partly between two plies of the support part. Such a support thus incorporates the conduit function. Such a support can be produced by a pultrusion or extrusion method by drawing or gluing or welding.
The device may include a plurality of conduits separated from each other and each including a flexible part and a contact zone able to come into abutment on or to be separated from the member to be heated or to be cooled.
One and the same support part may be common to at least two conduits.
One and the same metal part intended to come into contact with the fluid and with the member may be common to a plurality of conduits.
Said metal part and/or the support part may be a metal sheet.
The device may include at least one elastic member mounted between the contact zone and the support part. In a variant, said elastic member may be mounted between the contact zone and the member to be heated or to be cooled.
Said elastic member may be of the shape memory type. Said elastic member may be housed in the conduit or outside it.
The elastic member may be formed by an element distinct from and separated from the flexible part of the conduit. In a variant, the elastic member may be formed by the flexible part itself, or by an element that is distinct from but incorporated in the flexible part.
The elastic member may be formed by a spring, for example a compression spring or a draw spring. The spring is for example a helical spring.
The device may include means for storing calories and/or frigories.
Said means for storing calories and/or frigories may include a phase-change material or PCM, for example water, glycol, a saline solution or paraffin. In particular, the thermal phase-change material (PCM) may consist of n-hexadecane, eicosane or a lithium salt, all having melting points below 50° C. As an alternative, the PCM material may be based on fatty acid or eutectic or hydrated salt, or fatty alcohols, for example. Such thermal storage means make it possible to accumulate thermal energy (calories or frigories) by latent heat (phase change) or by sensible heat.
These storage means may in particular be charged with calories or frigories during a first operating phase, or be discharged either by heating or by cooling the member, or through the fluid circulating in the conduits, in a second operating phase.
Said means for storing calories and/or frigories may be mounted in a conduit of the device or between two conduits of the device.
The conduit may include a reinforcement extending over all or part of the conduit. Said reinforcement may include reinforcement fibers embedded in or on the surface of a polymer matrix. The matrix is intended to fulfil the function of fluid tightness.
The thermal regulation device may include heating means able to heat said member and/or the fluid circulating in the conduit.
The heating means may be incorporated in the conduit.
The heating means may include metal or carbon fibers, coming for example from the reinforcement, able to form an electrical resistance capable of generating calories by Joule effect when a voltage is applied to said fibers or to said armoring.
Some of the reinforcement fibers may then fulfil both the function of reinforcement and the function of thermal heating.
The heating means may include a metal or carbon armoring able to form an electrical resistance capable of generating calories by Joule effect when a voltage is applied to said fibers or to said armoring.
The armoring may also fulfil the reinforcement function in addition to the heating function.
The reinforcement may be produced by means of a non-woven or woven structure.
The reinforcement may be obtained by braiding, knitting, yarn-covering or spiral winding of metal or carbon-based threads or fibers. The reinforcement threads or fibers may have a resistivity of between 1012 and 106 Ω·cm.
The reinforcement structure may be able to afford a flexibility of the conduit by a suitable arrangement of the threads or fibers.
The fluid-circulation conduit may be in the general form of a tube.
The fluid-circulation conduit may be in the general form of a pouch. The pouch may include a fluid inlet and a fluid outlet. The inlets and outlets of the pouch may be located at the same end of the pouch or respectively at two opposite ends of the pouch.
The pouch may include a wall with an annular cross-section, having a constant thickness over the entire periphery. Such a pouch may be produced by extrusion for example. Such a pouch does not have any covering of material over its thickness.
In a variant, the pouch may include a wall with an annular cross-section, having a covering zone wherein two wall thicknesses are sealingly attached to each other.
The pouch may be partly formed by the support part, for example a longitudinal member or a crossmember, or partly by a wall sealingly attached to the support part, so as to delimit an internal volume of the pouch with the support part.
The thermal regulation device may include at least one first movable plate able to come into abutment on the member to be heated or to be cooled, at least one second movable plate fixed with respect to the first movable plate, and at least one intermediate plate mounted between said movable plates, the first movable plate and the intermediate plate delimiting the conduit, the intermediate plate including at least one flexible protrusion forming the flexible part and able to deform according to the pressure of the fluid in the conduit, said protrusion extending through at least one opening in the second movable plate and being able to bear on a support part.
In operation, when the internal volume of the conduit is not supplied with pressurized fluid, the protrusion is not deformed and occupies a minimum volume so that the movable plates are separated from the member to be heated or to be cooled and are close to the support part.
Conversely, when the internal volume of the conduit is supplied with pressurized fluid, the protrusions are deformed or inflated by the pressurized fluid. This has the effect of increasing the dimension of said protrusions in the direction perpendicular to the plates, i.e. to increase the distance between the movable plates and the support part. This also has the effect of reducing the distance between the member to be heated or to be cooled and the first movable plate, until said first movable plate comes into contact with said member, so as to allow an exchange of heat between the fluid flowing or present in the conduit and said member.
The conduit may be in the general form of a pouch.
The inlet and the outlet may be located in two zones of the pouch separated from each other, for example at two ends of the pouch.
At least some of the conduits may be connected by fluidic-connection zones so as to form one or more channels in the general form of a coil or of chicanes extending from one conduit to the other. The conduits may be located at the same face of the member to be heated or to be cooled. The conduits may be connected “in series” one after the other, in “parallel”, or any combination of the two modes, by means of the connection zones.
At least one internal channel in the general form of a coil or including any type of chicane may be formed in at least one pouch of the aforementioned type.
The pouch may be formed by a first part forming in particular a first longitudinal face and a second part forming in particular a second longitudinal face, the two parts being assembled sealingly on one another. The longitudinal direction can be defined as the extension direction or the largest-dimension direction of the pouch.
The inlet and the outlet may be located at longitudinal faces of the pouch and may extend perpendicularly to the median general plane of the pouch. The inlet and the outlet may be located at opposite longitudinal ends of the pouch i.e. opposite to each other.
The inlet and the outlet may be located at the same longitudinal face of the pouch.
The inlet and the outlet may be located at the same longitudinal end of the pouch.
The inlet and the outlet may be located at two opposite longitudinal ends of the pouch.
The channel or channels may include a narrowing of its cross-section, gradual or not, for example from the inlet towards the outlet.
At least one conduit or at least one pouch may be provided with means for generating turbulence in the fluid flow passing through the conduits. These turbulence-generating means offer example formed by zones of material or corrugations, for example in the form of a chevron. It is also possible to form these turbulence-generating means by means of inserts. These means may be formed or molded on the walls or the faces of the conduit or of the pouch, or be formed by distinct pieces secured to said walls or faces of the conduit or of the pouch. These means may also be formed on a surface against which the conduit or the pouch comes to be pressed when the conduit or the pouch is subjected to a pressurized fluid, for example a face of the cells or of the support. The member to be heated or to be cooled may be one or more battery cells, for example for an automobile.
Each cell may have a roughly parallelepipedal form having first lateral faces and second lateral faces, the first faces having a larger dimension than the second faces. The conduits may extend along the first faces and/or the second faces.
Each cell may have a cylindrical shape. The cells may be arranged in a zigzag. The conduits may extend between the cells and have curved zones following the cylindrical shapes of the cells, at least in part.
The cells may be so-called pouch cells including a pouch made from aluminized multilayer film, or made from aluminum or from plastics material for example.
The cells, for example cylindrical, pouch or prismatic, can be housed in a support block made from thermally conductive material, at least one conduit being able to come into contact with at least one lateral face of said support block.
The device may include means for measuring and/or calculating the temperature of the cells, and regulation and/or control means for adapting the pressure of the fluid flowing in the conduits accordingly. The latter may also adapt the temperature of the fluid accordingly.
The device may include means for circulating the fluid in the conduits.
The invention also relates to an automobile, for example of the electric or hybrid type, characterized in that it includes at least one device of the aforementioned type.
The device includes fluid-circulation conduits 3 separated from each other and extending for example along the lateral walls with the smallest surface area 2a of the cells 2.
As can be seen in
The first ends 4 of the conduits 3 can be attached to the support 4a by gluing or welding or by riveting for example. In a variant, the support 4a can form the ends 4 of the conduits 3.
The middle zone 6 is flexible and deformable along an axis denoted X. The middle zone 6 is in the general form of a bellows. In particular, the middle zone 6 is formed by two lateral walls 6a of the conduit 3 each including zones 6b inclined with respect to the axis X, here two inclined zones 6b arranged symmetrically with respect to a mid-plane P located between the planes of the ends 4, 5 and parallel to said planes of the ends 4, 5.
A fluid, for example a heat-transfer fluid or a refrigerating fluid, circulates in the conduits 3.
Each conduit 3 is here formed in a single piece, for example made from elastomer material.
The elastomer material is for example of the TPV type. The elastomer material may be loaded, at least in one zone of the conduit 3, by means of a thermally conductive filler, for example graphite, in order to improve the heat exchanges between the fluid and the cells. The conduits 3 may alternatively be formed from metal or composite materials or multilayer film, or an association of a plurality of materials.
The middle zone 6 is able to deform according to the pressure of the fluid in the conduit 3, between a first position illustrated in
In the first position (
In the second position (
The device 1 may include means for measuring and/or calculating the temperature of the cells 2, and regulation and/or control means for adapting the pressure of the fluid flowing in the conduits 3 accordingly. The latter may also adapt the temperature of the fluid accordingly.
The first position may for example make it possible to provide the cooling of the cells 2 as needed. The second position may for example make it possible to avoid such cooling, in particular when they need to be heated, for example under winter conditions.
In this embodiment, the same sheet 7 is common to several conduits 3.
The sheet 7 is thus able to move in translation with respect to the first end 4, between a first position in which it is able to come into abutment against the cells 2 of the battery, and a second position in which it is separated from said cells 2.
Such an embodiment improves the conductivity of the contact zone between the conduits 3 and the cells 2.
The elastic members 8 exert a return force tending to bring together the support 4a and the sheet 7.
The number of conduits 9 filled with phase-change material may be variable, as well as the distribution thereof in the conduits 3 in which the fluid circulates.
The phase-change material 10 or PCM is for example water, glycol, a saline solution or paraffin. In particular, the phase-change material 10 may consist of n-hexadecane, eicosane or a lithium salt, all having melting points below 50° C. As an alternative, the phase-change material 10 may be based on fatty acid or eutectic or hydrated salt, or fatty alcohols, for example. Such a material is a thermal storage means making it possible to accumulate thermal energy (calories or frigories) by latent heat (phase change) or by sensible heat.
Such a material 10 may in particular be charged with calories or frigories during a first operating phase, or be discharged either by heating or by cooling the cells 2, or through the fluid circulating in the conduits 3, in a second operating phase.
The conduits 3 in which the fluid flows can serve for cooling the cells 2 and the phase-change material 10 can make it possible to store the calories when the thermal dissipation of the cells 2 is too great.
Conversely,
Naturally, it is possible to combine the use of conduits 3 both along the smallest lateral walls and along the largest lateral walls.
Each conduit extends for example in a plane perpendicular to the axes of the cells 2.
The first ends 4 of the conduits 3 may be secured to certain cells 2, which then serve as a fixed support, and the second ends 5 of the conduits 3 can be able to come into abutment on the opposite cells 2, according to the pressure of the fluid inside the conduits 3.
As is more clearly visible in
According to a variant illustrated in
In this embodiment, the reinforcement 13 is located at the internal face of the pouch 13.
Such a metal reinforcement 13 can also make it possible to favor the heat exchanges between the cells 2 and the fluid circulating in the pouch 3.
Each pouch 3 is partly formed by the support part 4a, and partly by a wall or a flexible sheet 3b sealingly secured to the support part 4a at the bottom and top edges thereof, so as to delimit an internal volume of the pouch 3 with the support part 4a.
The cells 2 may be so-called pouch cells each including a pouch made from aluminum or plastics material for example.
The pouch 3 is for example formed by a first part 31 forming in particular a first longitudinal face 31a and a second part 32 forming in particular a second longitudinal face 32a, the two parts 31, 32 being assembled sealingly on one another. The longitudinal direction L is here defined as the extension direction or the largest-dimension direction of the pouch 3.
In this embodiment, the inlet 24 and the outlet 35 are located at longitudinal faces 31a, 32a of the pouch 3 and extend perpendicularly to the median general plane of the pouch 3. The inlet 24 and the outlet 25 are here located at opposite longitudinal ends of the pouch 3, i.e. opposite to each other.
Moreover, the channel may include a narrowing of its cross-section, gradual or not, for example from the inlet towards the outlet, as illustrated on this figure. Such a narrowing is also applicable to the other embodiments.
It is also possible to form these turbulence-generating means by means of inserts distinct from the conduits 3 and secured to or inserted in the relevant conduit 3. These means may be formed or molded on the walls or the faces 31a, 32a of the conduit 3, or be formed by distinct pieces secured to said walls or faces 31a, 32a of the conduit 3. These means may also be formed on a surface against which the conduit 3 comes to be pressed when the conduit is subjected to a pressurized fluid, for example a face of the cells 2a or of the support 4a. Naturally, such turbulence-generating means may be applied to the embodiments including a pouch.
Number | Date | Country | Kind |
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FR2014072 | Dec 2020 | FR | national |
Filing Document | Filing Date | Country | Kind |
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PCT/FR2021/052390 | 12/17/2021 | WO |