Thermal regulation system for an electrical energy storage device.

Abstract

Title of the invention: Thermal regulation system for an electrical energy storage device. The present invention relates to a thermal regulation system for an electrical energy storage device, the electrical energy storage device comprising a housing and a plurality of thermally regulated components (6) housed within the housing and aligned side by side in a stacking direction, characterized in that the thermal regulation system comprises at least one plate (12) intended to be disposed between two adjacent thermally regulated components (6), the plate (12) comprising at least one dielectric fluid circulation conduit (18) comprising a main branch and at least one secondary branch participating in the formation of a passive check valve. (Figure 2)

Description

Title of the invention: Thermal regulation system for an electrical energy storage device.

[0001] The field of the present invention is that of thermal regulation systems. The present invention relates more particularly to the circulation of a fluid within such thermal regulation systems to carry out a heat exchange with components of an electrical energy storage device.

[0002] It is known nowadays to equip electric, thermal or hybrid vehicles with electrical energy storage devices allowing an electrical supply to the various elements of the vehicle. These electrical energy storage devices comprise components to be thermally regulated positioned in a battery pack.

[0003] Car manufacturers are currently seeking to provide more powerful electric or hybrid vehicles with increased electric range. To this end, more and more battery packs, and / or increasingly larger battery packs, are being installed on these electric or hybrid vehicles.

[0004] During vehicle operation, battery packs can release a significant amount of heat and therefore be subject to temperature increases which can in some cases cause their damage or even destruction. Consequently, providing effective cooling is essential in order to keep them in good condition and thus ensure the reliability, autonomy and performance of the vehicle. Furthermore, the operation of battery packs can be less efficient in the event of low temperatures, the electrical or electronic components equipping these battery packs then needing time to warm up before operating at full efficiency.

[0005] To do this, one or more thermal regulation systems intended to regulate the temperature of the battery packs are implemented to ensure the preheating and / or cooling functions of the electrical or electronic components inside these battery packs and thus optimize the operation of the different components.

[0006] These thermal regulation systems are generally traversed by a heat transfer fluid which can, depending on requirements, either absorb the heat emitted by each battery pack in order to cool it or provide heat if the temperature of the battery pack is insufficient for its proper functioning.

[0007] It is known that thermal regulation systems can consist, for example, of a flat plate on which is attached a stamped plate of so as to form, between the flat plate and the bosses of the stamped plate, a conduit intended to be traversed by the heat transfer fluid. Alternatively, it is known to provide tube systems, obtained for example by extrusion, with a plurality of parallel circulation conduits extending within the tube.

[0008] However, the production of such conduits is not optimal, either because it requires numerous assembly steps increasing the manufacturing costs of the thermal regulation system, or because it does not allow an optimized heat exchange between the fluid circulating in such conduits and the components of the battery pack, which limits the capacity of the thermal regulation system to carry out a heat exchange with components of the electrical energy storage device.

[0009] The present invention falls within this context and proposes to overcome at least some of the drawbacks of the prior art. The present invention proposes in particular to facilitate the production of the conduits and to improve the heat exchange between a fluid circulating in these conduits and components of the electrical energy storage device.

[0010] Thus, an object of the present invention is a thermal regulation system for an electrical energy storage device, the electrical energy storage device comprising a housing and a plurality of components to be thermally regulated housed in the housing and aligned next to each other in a stacking direction, the thermal regulation system comprising at least one plate intended to be arranged between two adjacent components to be thermally regulated, the plate comprising at least one dielectric fluid circulation conduit comprising a main branch and at least one secondary branch participating in forming a passive non-return device.

[0011] The electrical energy storage device is intended to equip a vehicle in order to deliver electrical energy to different elements of the vehicle, such as for example a powertrain, lighting equipment, a ventilation, heating and / or air conditioning system. Components which may for example be electrochemical cells participate in the operation of the electrical energy storage device. These components are to be thermally regulated by the thermal regulation system, here by means of at least one plate arranged between two adjacent components.

[0012] The plate of the regulation system is interposed between two components. At least one part of the plate is in contact with one of said components and at least another part of said plate is in contact with another adjacent component. It is understood that the components are said to be aligned in a stacking direction in that they are arranged in parallel to each other, perpendicular to this stacking direction, in a housing forming a means of protecting these components, and we understand that the plate is said to be interposed between two components to the extent that it is placed in contact with each of two neighboring components.

[0013] Within a circulation duct, the main branch and the at least one secondary branch make it possible to promote the circulation of the dielectric fluid in a given circulation direction, for example going from one end edge of the plate to the opposite end edge of this plate. The circulation of the dielectric fluid in a circulation direction opposite to the promoted circulation direction is constrained by the flow of the dielectric fluid within the circulation duct. Thus, the circulation duct forms a passive non-return device in that the flow of the dielectric fluid is forced in one circulation direction within the circulation duct by the shape of the main branch and the at least one secondary branch, this forced flow preventing circulation in the opposite direction.In other words, the circulation duct does not include a moving element to prevent the return of the dielectric fluid and only the shape of the circulation duct with the main branch and the secondary branch(es) makes it possible to achieve this non-return.

[0014] According to an optional characteristic of the invention, the plate comprises at least one circulation duct extending along a direction perpendicular to the stacking direction of the components. This circulation duct is capable of circulating the dielectric fluid from one end of the plate to an opposite end of said plate. When a plate comprises several circulation ducts, the dielectric fluid circulates in each circulation duct from the same end of the plate to the same opposite end of said plate.

[0015] According to a characteristic of the invention, the circulation duct is configured to allow the circulation of the dielectric fluid from one end edge of the plate to an opposite end edge of said plate by natural convection. In other words, the configuration of the circulation duct allows, when the dielectric fluid recovers calories released by at least one component of the battery pack, and in particular during a thermal runaway that one seeks to contain as much as possible, to see the dielectric fluid, the density of which has decreased, circulate naturally in the circulation duct, in a main direction of movement opposite to that of gravity. This natural convection is allowed in particular by an inclined shape of the main branch relative to the straight direction between the end edges mentioned, with in particular a sawtooth shape.

[0016] Furthermore, the circulation duct has a small passage section, both for the main branch and for the at least one secondary branch.

[0017] As a non-limiting example of the invention, this passage section is of the order of 5 to 30 mm2. This reduced size of the circulation conduit allows a high speed of propagation of the dielectric fluid within the circulation conduit, which allows efficient heat exchanges and which can also participate in the natural convection of the dielectric fluid when this is necessary.

[0018] According to a characteristic of the invention, the dielectric fluid circulation conduit has a Tesla valve shape. This Tesla valve, also known as a valve conduit, makes it possible to promote the flow of the dielectric fluid in one direction of circulation and to restrict the circulation of the dielectric fluid in an opposite direction of circulation.

[0019] According to a characteristic of the invention, the at least one plate comprises a first face configured to come at least partly into contact with a first component to be thermally regulated and a second face configured to come at least partly into contact with a second component to be thermally regulated, the at least one plate comprising a thickness which is defined between the first face and the second face and in which the at least one circulation conduit is made.

[0020] The components to be thermally regulated are aligned next to each other, i.e. arranged in parallel to each other in the stacking direction, such that each component to be thermally regulated of the electrical energy storage device has a first face which is opposite a second face of another component to be thermally regulated. The first and second faces of the components to be thermally regulated are the largest faces of these components.

[0021] According to an optional characteristic of the invention, the at least one circulation duct is formed strictly in the thickness of the plate.

[0022] According to a characteristic of the invention, the at least one plate comprises at least one imprint participating in forming the at least one circulation conduit, the at least one imprint being open on at least one of said faces of the at least one plate.

[0023] This imprint corresponds to a groove formed in the plate to form a circulation duct. This imprint is open on one face so that the circulation channel is, when the electrical energy storage device comprising the regulation system is assembled, delimited by the groove and by a component to be thermally regulated which covers this groove. Thus, the dielectric fluid circulating in a circulation duct is continuously in contact with a component so as to promote the exchange of calories between the dielectric fluid and said component. According to the embodiment variants, the imprint is open on only one of the faces if it has a bottom wall and does not extend over the entire thickness of the plate, and it is open on both faces, opening onto each of the faces of the plate, if it extends over the entire thickness of the plate.

[0024] According to an optional characteristic of the invention, the imprint participating in forming said circulation conduit extends from one of said ends of the plate to an opposite end.

[0025] According to an optional characteristic of the invention, the at least one plate comprises a plurality of open impressions in regular alternation on the first face and on the second face. In this context, the impressions are open on a single face of the plate, in particular to allow easy production of the plate in one piece with impressions which have the same depth from one end of the plate to the other, and the fact of producing a regular alternation between an open impression on the first face and an open impression on the second face makes it possible to make the distribution of the dielectric fluid in contact with one or other of the components to be thermally regulated arranged on either side of the plate homogeneous.

[0026] According to an optional characteristic of the invention, the at least one plate comprises at least two circulation conduits extending in parallel to one another along a main circulation direction of the dielectric fluid between a fluid inlet through which the dielectric fluid is able to enter the circulation conduit and a fluid outlet through which the dielectric fluid is able to exit the circulation conduit.

[0027] By "in parallel with each other" it is understood that each circulation conduit is supplied with dielectric fluid from the same edge, or same end, of the plate and opens onto the same other edge, or opposite end, of the plate.

[0028] According to a characteristic of the invention, the at least one secondary branch forms a bypass loop around an obstruction element, said secondary branch comprising a first curved portion connected to the main branch in a first connection zone and a second rectilinear portion connected to the main branch in a second connection zone.

[0029] The first curved portion and the second rectilinear portion are delimited at least in part by the same obstruction element. The obstruction element participates in forming the first curved portion of the secondary branch by a main body, the circumference of which is circular, and it participates in forming the second connection zone between the main branch and the second rectilinear portion of the secondary branch by a pointed end which extends the main body. The circular main body and the pointed end of the obstruction element give it a drop shape.

[0030] A secondary branch is arranged along the main branch such that the first connection zone is positioned in a portion of the main branch where the dielectric fluid flows in a laminar manner. Locally, the passage of the dielectric fluid in a curved portion of a secondary branch involves circulation with a turn to be taken of the order of 90° or more, which makes that most of the dielectric fluid continues its path along the main branch. Thus, a small proportion of the dielectric fluid is diverted when the dielectric fluid first encounters the first curved portion of a branch loop without decreasing the efficiency of circulation within the circulation conduit.

[0031] According to a characteristic of the invention, the at least one plate comprises a plurality of obstruction elements arranged laterally relative to the main branch. The secondary branches can thus be arranged on either side of the main branch. Here again, the first connection zones of these secondary branches are successively positioned in portions of the main branch where the dielectric fluid circulates in a laminar manner.

[0032] The at least one plate comprises a plurality of obstruction elements, each obstruction element being disposed along the main branch and each secondary branch being formed around a specific obstruction element.

[0033] According to a characteristic of the invention, the obstruction element closest to the fluid inlet of a circulation conduit produced on the first face is arranged on a first side of the main branch and the obstruction element closest to the fluid inlet of a circulation conduit produced on the second face is arranged on a second side, opposite the first side with respect to the main branch.

[0034] In other words, looking at the first face of a plate, all circulation conduits have an obstruction element closest to the fluid inlet which is on the left side of the main branch while looking at the second face of a plate, all circulation conduits have an obstruction element closest to the fluid inlet which is on the right side of the main branch.

[0035] According to a characteristic of the invention, the distance between the fluid inlet and the first curved portion is less than the distance between the fluid inlet and the second rectilinear portion, this distance being measured along the main circulation direction.

[0036] Another object of the present invention is an electrical energy storage device comprising a thermal regulation system, in which at least one circulation duct open on the first face of the at least one plate is delimited at least in part by a first component to be thermally regulated and at least one second circulation duct open on the second face of the at least one plate is delimited at least in part by a second component to be thermally regulated.

[0037] According to a characteristic of the invention, the housing comprises a lower wall and an upper wall between which the components are arranged, the at least one circulation conduit being configured to allow the circulation of the dielectric fluid from an end edge of the at least one plate facing the wall in lower edge of the housing to an end edge of said plate facing the upper wall of said housing.

[0038] According to a characteristic of the invention, the plate is made of a thermally non-conductive material.

[0039] Other characteristics, details and advantages of the invention will emerge more clearly on reading the description which follows on the one hand, and several exemplary embodiments given for informational and non-limiting purposes with reference to the appended schematic drawings on the other hand, in which:

[0040] [Fig.l] schematically represents an electrical energy storage device according to the present invention comprising a housing and a plurality of components to be thermally regulated housed in the housing, plates of a thermal regulation system being interposed between the components to be thermally regulated;

[0041] [Fig.2] schematically represents visible thermally regulated components in [Fig.l] separated from each other by a plate of a thermal regulation system according to the present invention;

[0042] [Fig.3] schematically represents the plate of the thermal regulation system visible in [Fig.2] on which a plurality of conduits for circulating a dielectric fluid are made;

[0043] [Fig.4] schematically represents a detailed view of a circulation duct made in the plate visible in [Fig.3];

[0044] [Fig.5] schematically represents a sectional view of the plate visible on the [Fig.3] highlighting the circulation conduits made on a first face of the plate;

[0045] [Fig.6] schematically represents a sectional view of the plate visible on the [Fig.3] highlighting the circulation conduits made on a second face of the plate;

[0046] [Fig.7] schematically represents the plate of a thermal regulation system according to an alternative embodiment, in a view similar to that of [Fig.3].

[0047] The features, variants and different embodiments of the invention may be combined with each other, in various combinations, provided that they are not incompatible or mutually exclusive. In particular, variants of the invention may be imagined comprising only a selection of features described below in isolation from the other features described, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from the state of the prior art.

[0048] In the following description, the terms “longitudinal”, “transverse” and “vertical” refer to the orientation of a regulation system. thermal regulation system according to the invention. A longitudinal direction corresponds to a main extension direction of a plate of the thermal regulation system comprising at least one circulation duct, this longitudinal direction being parallel to a longitudinal axis L of a reference L, V, T illustrated in the figures. A transverse direction corresponds to a direction joining one end of said plate intended to be in contact with a component to be thermally regulated of the electrical energy storage device to an opposite end of said plate intended to be in contact with another component to be thermally regulated of the electrical energy storage device, this transverse direction being parallel to a transverse axis T of the reference L, V, T, and perpendicular to the longitudinal axis L. Finally, a vertical direction corresponds to a vertical axis V of this reference L, V, T, this vertical axis V being perpendicular to the longitudinal axis L and the transverse axis T.

[0049] [Fig.l] illustrates an electrical energy storage device 2 intended to equip a vehicle. The electrical energy storage device 2 comprises a housing 4 and a plurality of components 6 to be thermally regulated, which will generally be called components hereinafter. In the embodiment shown, each of the components 6 of the electrical energy storage device 2 forms an electrochemical cell participating in the operation of the electrical energy storage device 2. More specifically, in the description relating to the various embodiments which will follow, the references made to one or more components 6 should be understood as indicating one or more electrochemical cells. Of course, the invention is not limited to a particular form of electrochemical cells.

[0050] The housing 4 is illustrated in sectional view in [Fig.l] to make visible the plurality of components 6 housed in the housing 4. The housing 4 forms a hermetic enclosure separating the components 6 from the environment external to the housing 4. To ensure the proper functioning of the components 6, the temperature of said components 6 is controlled. More particularly, the components 6 are elements of the electrical energy storage device 2 having optimal operation at a given working temperature. In addition, during their operation, the components 6 generate heat. To ensure that the components 6 are always at their working temperature, the electrical energy storage device 2 comprises a thermal regulation system participating in regulating the temperature of the components 6.

[0051] The thermal regulation system comprises in particular means for circulating a heat transfer fluid capable of exchanging calories with components 6, for example to heat said components 6 when the electrical energy storage device 2 is switched on and thus reach the working temperature of the components 6 more quickly, or by transferring calories from the components 6 to the heat transfer fluid, for example to lower the temperature of the components 6 during prolonged operation.

[0052] For this purpose, the components 6 are immersed in the heat transfer fluid and the thermal regulation system further comprises plates 12 interposed between the components and which will be detailed below. This heat transfer fluid is a dielectric fluid coming directly into contact with the components 6. The contact between the dielectric fluid and the components 6 makes it possible to carry out an exchange of calories between the dielectric fluid and the components 6. The hermetic enclosure formed by the housing 4 makes it possible to permanently maintain a quantity of dielectric fluid within the housing 4 sufficient for the components 6 to be at least partially continuously immersed in the dielectric fluid. Means for circulating and regulating, not shown, the dielectric fluid from the inside of the housing 4 to the outside of the housing 4, and vice versa, are implemented to allow the regulation of the temperature of the dielectric fluid outside the housing.

[0053] As visible in [Fig.l], the components 6 are aligned next to each other, that is to say arranged in parallel to each other, in a stacking direction, this stacking direction being here parallel to the transverse axis T. Furthermore, each component 6 has, in the embodiment shown, a generally parallelepiped shape and extends in a main longitudinal extension direction, that is to say parallel to the axis L, from a first lateral end 8 to a second opposite lateral end 10. In the embodiment shown, each component 6 has dimensions measured in the longitudinal direction, the transverse direction and the vertical direction which are substantially equal to each other.

[0054] The alignment of the components 6 is such that the stacking direction of the components 6 is perpendicular to the main longitudinal extension direction of said components 6. In addition, when the components 6 are aligned with each other, the first lateral ends 8 and the second lateral ends 10 of the components 6 are respectively inscribed in the same plane.

[0055] To ensure optimal heat exchange between the dielectric fluid and the components 6, a component 6 is separated from an adjacent component 6 by a plate 12 of the thermal regulation system. The plate 12 is configured to allow the dielectric fluid to circulate between two adjacent components 6 by performing a heat exchange with said components 6. In addition, the plate 12 makes it possible to limit the formation of thermal bridges between two adjacent components 6, the plate 12 being made of a thermally non-conductive material. It should be noted that, in the embodiment shown, the electrical energy storage device 2 comprises a plurality of plates 12, the number of plates 12 being equal to the number of components 6 minus one. Of course, the invention is not limited to this embodiment. embodiment and a single plate 12 of the type which will be described could be used, for example to optimize the thermal regulation of components 6 likely to thermally run away more than others.

[0056] [Fig. 2] illustrates components 6 visible in [Fig. 1]. More specifically, in this [Fig. 2] an end component 6 has been removed to make a plate 12 visible in more detail.

[0057] As seen in [Fig. 2], each plate 12 has dimensions, measured in the longitudinal and vertical directions, which are substantially equal to each other. Said dimensions of the plates 12 measured in the longitudinal and vertical directions are substantially equal to the dimensions of the components 6 measured in said longitudinal and vertical directions.

[0058] In addition, each plate 12 extends in a main longitudinal elongation direction, this main longitudinal elongation direction being parallel to the main longitudinal extension direction of the components 6. More particularly, each plate 12 has a general parallelepiped shape complementary to the general parallelepiped shape of the components 6 allowing said plates 12 to be pressed against the components 6 without protruding from the general parallelepiped shape of the components 6.

[0059] Thus, the plates 12 are interposed between two adjacent components so that the plates 12 and the components 6 are aligned with each other, or superimposed on each other, along the stacking direction. As a result, an assembly formed by the components 6 and the plates 12 is inscribed in a generally parallelepiped shape.

[0060] Each plate 12 comprises a first face 14 configured to come into contact with a first component 6 and a second opposite face 16 configured to come into contact with a second component 6, the first and second components being adjacent. The first face 14 and the second face 16 comprise at least one circulation duct 18 made in a thickness 20 of the plate 12 defined between the first face 14 and the second face 16 of said plate 12. In the embodiment shown, the first face 14 and the second face 16 each comprise a plurality of circulation ducts 18 made on each face 14, 16 and arranged next to each other.As will be described below, it is the circulation of the dielectric fluid in a circulation conduit 18 which allows the thermal regulation of the component, so that one would not depart from the context of the invention if a single circulation conduit in accordance with what will be described were provided in a single face of a plate 12, since this face is in contact with a component 6 to be thermally regulated.

[0061] To form the at least one circulation conduit 18, each plate 12 comprises at least at least one imprint 22 participating in forming said circulation duct 18. In the embodiment shown, each face 14, 16 comprises a plurality of imprints 22 each participating in forming a circulation duct.

[0062] Each imprint 22 is open on a face 14, 16 of a plate 12. In the example illustrated, each imprint 22 is open on a single face 14, 16 of a plate 12, it being understood that some of the imprints are open on a first face 14 of the plate 12 and that others are open on a second face 16 of this plate 12. A circulation duct 18 is thus delimited on the one hand by the material of the plate 12 delimiting the imprint open on a given face of this plate and on the other hand by the component 6 to be thermally regulated which is arranged against this given face.Thus, the circulation ducts 18 formed in part by the indentations 22 open on the first face 14 are delimited by the plate 12 and the first component arranged against the first face 14 and the circulation ducts 18 formed in part by the indentations 22 open on the second face 16 are delimited by the plate 12 and the second component arranged against the second face.

[0063] Furthermore, each circulation duct 18 extends mainly along a main circulation direction of the dielectric fluid which is parallel to the vertical direction between a fluid inlet 24 through which the dielectric fluid is able to enter a circulation duct 18 and a fluid outlet 26 through which the dielectric fluid is able to leave said circulation duct 18. It is understood that this main circulation direction of the dielectric fluid is perpendicular to the stacking direction of the components 6. In this context, the circulation ducts 18 formed by the indentations 22 open on the first face 14 and on the second face 16 extend parallel to each other.

[0064] When the electrical energy storage device 2 is installed in the vehicle, the circulation conduits 18 are made such that the fluid inlet 24 is closer to the ground on which the vehicle is traveling than the fluid outlet 26. In addition, the circulation conduits 18 are made such that the main circulation direction of the dielectric fluid along which the circulation conduits 18 extend is substantially vertical when the vehicle equipped with the electrical energy storage device 2 is traveling on a horizontal road, and more generally substantially perpendicular to the direction of travel of the vehicle.

[0065] This orientation of the circulation conduits 18 allows the dielectric fluid to circulate in each circulation conduit 18 from an end edge of a plate 12 opposite a lower wall 25 of the housing 4, visible in [Fig. 1], to an end edge of said plate 12 opposite an upper wall 27 of the housing 4, visible in [Fig. 1]. This circulation from bottom to top is particularly encouraged, when these are in operation, by the circulation and regulation means.

[0066] In the example illustrated, in order to allow regular and homogeneous thermal regulation of the adjacent components arranged on either side of the same plate 12, the impressions 22 made on this plate 12 are open in regular alternation on the first face 14 and on the second face 16 as will be described in more detail in connection with FIGS. 5 and 6.

[0067] Figures 3 and 4 illustrate detailed views of the indentations 22 open on the first face 14 of a plate 12 and forming circulation conduits 18. These circulation conduits 18 each comprise a main branch 28 and at least one secondary branch 30. It should be noted that in the embodiment shown, the circulation conduits 18 comprise a plurality of secondary branches 30.

[0068] The main branch 28 forms the part of the circulation conduit 18 through which the dielectric fluid preferentially circulates from the fluid inlet 24 to the fluid outlet 26. For this purpose, the main branch 28 extends in a sawtooth pattern along a main circulation direction going from the fluid inlet 24 to the fluid outlet 26. The main branch 28 thus has substantially rectilinear portions which follow one another while being inclined relative to the main circulation direction, substantially with the same angle α, visible in [Fig. 3], once positive, once negative. This angle α may be of the order of 10° to 30°, without this being limiting of the invention.This inclination, combined with a small passage section of the dielectric fluid within the circulation duct, allows rapid progression of the dielectric fluid from one end of the plate to the other and generates only a small pressure drop, thus having a small impact on the flow of the dielectric fluid from the fluid inlet 24 to the fluid outlet 26. It is notable that at each bifurcation of the main branch, generated by a change in orientation relative to the main circulation direction, an obstruction element 32, described below, helps to form a curved zone inside the bifurcation to facilitate the flow of the dielectric fluid along the main branch. The sawtooth shape is illustrated in bold dotted lines for one of the circulation ducts in [Fig.3].

[0069] The secondary branches 30 form bypass portions, arranged on either side of the main branch 28, into which a portion of dielectric fluid is likely to flow during the advancement of the dielectric fluid from one end to the other, but in tiny proportions due to the arrangement of the connection zones of the secondary branches 30 on the main branch.

[0070] More particularly, the main branch 28, the secondary branches 30 and the connection zones are delimited within the circulation duct 18 by the presence of obstruction elements 32. The obstruction elements 32 are formed in the thickness of the plate 12 and form projecting elements due to the production of the impression around them. In the example illustrated, the obstruction elements 32 are distributed laterally on either side of the main branch 28, each obstruction element participating in delimiting on the one hand a portion of the main branch 28 and on the other hand a secondary branch 30. Thus, as seen in more detail in [Fig.4], a portion of the main branch 28 extends between two adjacent obstruction elements and each secondary branch 30 forms a bypass loop around an obstruction element 32.

[0071] As can be seen in particular in [Fig. 4], each secondary branch 30 is connected to the main branch by a first connection zone 31 and a second connection zone 33 and it comprises a first curved portion 34 and a second rectilinear portion 36. The respective shapes of the first curved portion 34 and the second rectilinear portion 36 are obtained, in particular, by the shape of the obstruction elements 32. More specifically, the obstruction elements 32 each have a main body 320, the periphery of which is circular and which is extended by a pointed end 322, these obstruction elements 32 thus taking a general drop shape. The curvature of the main body 320 helps to define the curvature of the first curved portion 34 and the second rectilinear portion extends along the pointed end 322.More particularly, the first curved portion 34 extends from a first connection zone 31 all around the main body of circular shape and the second rectilinear portion extends in the extension of the first curved portion along the pointed end to the second connection zone 322.

[0072] The distance between the fluid inlet 24 and the first curved portion 34 of a secondary branch 30 is less than the distance between the fluid inlet 24 and the second straight portion 36 of the same secondary branch 30, this distance being measured along the main circulation direction. This characteristic allows the dielectric fluid circulating in a secondary branch 30 from the fluid inlet 24 to the fluid outlet 26 to flow from the first curved portion 34 to the second straight portion 36.

[0073] It results from this arrangement that the two connection zones are particularly different from each other. The first connection zone 31 is formed by a circular portion of the secondary branch 30 which opens into a rectilinear portion of the main branch 28, with an orientation such that the tangent to the circular portion at the level of the first connection zone 31 forms an angle [3 with the rectilinear portion going beyond 90°, as visible in [Fig. 4] in particular. This has the effect of complicating the circulation of the dielectric fluid from the primary branch to the secondary branch, which tends to favor the circulation of the fluid mainly through the primary branch 28. This also has the effect, if the dielectric fluid were to circulate in the other direction from the fluid outlet 26 towards the fluid inlet 24, to create a vortex at the level of the first connection zone, with the portion of dielectric fluid caused to circulate from the secondary branch towards the primary branch which meets the portion of dielectric fluid circulating in the primary branch, these portions of fluid circulating locally in the opposite direction.

[0074] The second connection zone 33 is formed by the junction of two rectilinear portions, extending substantially symmetrically on either side of the pointed end 322 of the obstruction element 32. Whether in one direction of circulation or the other, this second connection zone generates little or no turbulence.

[0075] The shape taken by the circulation duct 18 allows the dielectric fluid, and in particular when the circulation and regulation means are inoperative, for example in the event of a malfunction likely to cause thermal runaway within the battery pack, to circulate preferentially from the fluid inlet 24 to the fluid outlet 26, thereby forming a passive non-return device which prevents the dielectric fluid from circulating from the fluid outlet to the fluid inlet. This is particularly advantageous in a case of thermal runaway, because the dielectric fluid, caused to recover a lot of calories from the components of the battery pack, sees its density lowered and naturally tends to rise in the circulation duct and it is advantageous that less hot dielectric fluid, and therefore coming from the bottom of the housing, can replace the hotter dielectric fluid in the circulation duct.

[0076] It is understood from the above that the dielectric fluid, circulating in a circulation conduit 18 in a circulation direction going from the fluid inlet 24 to the fluid outlet 26, circulates mainly in the main branch 28 and secondarily in a secondary branch 30 passing successively through the first curved portion 34 then through the second rectilinear portion 36.

[0077] When the dielectric fluid flows from the fluid inlet 24 to the fluid outlet 26, the first curved portion 34 diverts a small volume of dielectric fluid from the main branch 28 due to the change of direction with an angle [3 greater than 90° taken momentarily by the dielectric fluid with respect to the main circulation direction. In addition, since the second connection zone does not generate disturbances on the path of the dielectric fluid within the main branch 28, the flow along this branch from the fluid inlet 24 to the fluid outlet 26 is favored.

[0078] Conversely, when the dielectric fluid attempts to circulate through the circulation conduit 18 in a circulation direction going from the fluid outlet 26 to the fluid inlet 24, the dielectric fluid is split into two substantially equal portions at the level of the second connection zones 33. In this direction of circulation of the fluid dielectric, the dielectric fluid joins the main branch 28 from a secondary branch 30 via the first curved portion 34. At the first connection zone, the dielectric fluid then joins the main branch 28 with a flow direction which is different, almost opposite, to the flow direction of the dielectric fluid already present in the main branch 28. These flows in two opposite directions of the dielectric fluid generate turbulence constraining the flow of the dielectric fluid from the fluid outlet 26 to the fluid inlet 24. As mentioned, the circulation conduit 18 thus forms a passive non-return device in which the circulation of the dielectric fluid from the fluid outlet 26 to the fluid inlet 24 is constrained by the shape of the main branch 28 and the secondary branches 30.

[0079] Thus, a circulation conduit 18 forms a Tesla valve, in other words a valvular conduit. The circulation conduits 18 thus make it possible to force the circulation of the dielectric fluid from the fluid inlet 24 to the fluid outlet 26, in particular the circulation and regulation means malfunction.

[0080] This general shape taken by the circulation duct 18 as well as the orientation of the circulation duct 18, that is to say the fluid inlet 24 arranged at a lower portion of the housing 4 and the fluid outlet 26 at an upper portion of the housing 4, allows the dielectric fluid to circulate in the circulation duct 18 by natural convection.

[0081] Indeed, on the one hand, the main branch 28 and the secondary branches 30 have a small section compared to a single channel which would be formed in the plate 12. This small section promotes the circulation of the dielectric fluid by capillarity and increases the flow speed of the fluid which promotes the thermal exchanges between the dielectric fluid and the component 6. On the other hand, as mentioned, the lowering of the density of the dielectric fluid in the event of heating allows it to naturally rise in the circulation conduit 18.

[0082] Such a feature allows the regulation system to ensure the thermal regulation of the components 6 in a situation where, for example, a pump participating in forcing the circulation of the dielectric fluid from the lower part of the housing 4 to the upper part of said housing 4 is stopped. Indeed, the natural convection of the fluid within the circulation duct 18 supported by the characteristics of the main branch 28 and the secondary branches 30 of having a small section and of participating in forming a non-return device makes it possible to ensure the circulation of the dielectric fluid within the circulation duct 18.

[0083] Figures 5 and 6 illustrate a sectional view of a plate 12 made at a sectional plane represented by the axis 40 visible in [Fig. 3]. More specifically, [Fig. 5] illustrates the first face 14 of a plate 12 and [Fig. 6] illustrates the second face 16 of said plate 12.

[0084] These figures make more particularly visible the characteristic of an alternating arrangement of the indentations 22 on one face then the other. For each indentation 22 which is open on the first face 14, the part of the second face 16 opposite this indentation 22 is solid and not provided with a circulation conduit. Conversely, for each indentation 22 which is open on the second face 16, the part of the first face 14 opposite this indentation 22 is solid and not provided with a circulation conduit. It is understood that this makes it possible to make indentations over a depth which is greater than half the thickness of the plate, without an indentation made on a first face 14 meeting an indentation made on a second face 16. This alternating arrangement makes it possible to maximize the presence of the circulation conduits 18 on the plate 12 and to promote thermal exchanges between the dielectric fluid and the components 6.

[0085] It is remarkable in Figures 5 and 6 that the circulation ducts 18 produced on the same face 14, 16 of the plate 12 are identical to each other, that is to say that their images are superimposable with respect to each other. And it is notable that the projections of the circulation ducts 18 produced on the first face 14 and on the second face 16 in a transverse direction are identical with respect to each other. In other words, the projections of all the circulation ducts on the same face are superimposable with each other.

[0086] This configuration is obtained in particular by modifying the alternation of the obstruction elements 32 distributed on either side of the main branch 28 between the circulation conduits 18 produced on the first face 14 and the circulation conduits 18 produced on the second face 16.

[0087] More specifically, the obstruction element 32 closest to the fluid inlet 24 of a circulation conduit 18 produced on the first face 14 is arranged on a first side of the main branch 28, here to the left of the main branch 28, and the obstruction element 32 closest to the fluid inlet 24 of a circulation conduit 18 produced on the second face 16 is arranged on a second side of the main branch 28, here to the right of the main branch 28.

[0088] Here again, this makes it possible to optimize the presence of the prints on the given surface of a face, since in a circulation duct of a first face 14, the obstruction element which is closest to the fluid inlet can extend slightly into the projection zone of the circulation duct of the second face 16, since this closure element is not transversely opposite the corresponding obstruction element of the circulation duct of the second face.

[0089] [Fig.7] illustrates an alternative embodiment of the invention, which differs from what has previously described by the arrangement of the circulation ducts 18 for one face plate data.

[0090] In this variant embodiment, the circulation conduits 18 formed by the indentations 22 open on the same face, here the first face 14, extend again, in accordance with what has been previously described, parallel to each other.

[0091] The arrangement of the circulation ducts 18 differs in that they are here symmetrical from near to far, with respect to a plane perpendicular to the first face and extending parallel to the main elongation direction of these circulation ducts. In other words, a circulation duct 18 produced in the first face has a neighboring circulation duct which is arranged differently, with a symmetrical orientation with respect to a plane of symmetry arranged between this circulation duct and the neighboring circulation duct. In the example illustrated in [Fig. 7], a circulation duct 18 is thus the symmetrical of a first neighboring circulation duct with respect to a first plane of symmetry PSI arranged on one side of the circulation duct 18 and it is also the symmetrical of a second neighboring circulation duct with respect to a second plane of symmetry PS2 arranged on an opposite side of the circulation duct 18.

[0092] Unlike what was present in the previous embodiment, the projections on the same face of two neighboring circulation conduits are not superimposable on each other. This results in a different distribution of the contact zones of the dielectric fluid with the component to be thermally regulated.

[0093] As just described, the present invention achieves the aim it set itself by proposing a thermal regulation system comprising a plate interposed between two components to be thermally regulated on which at least one circulation duct is produced. This circulation duct is configured to form a passive non-return device and improve the thermal exchanges between a dielectric fluid circulating in the circulation duct and at least one component.

[0094] The present invention cannot, however, be limited to the means and configurations described and illustrated here and it also extends to any equivalent means and configuration as well as to any technically operative combination of such means. As a non-limiting example of an alternative embodiment of the invention not shown, the circulation conduits could be formed strictly in the thickness of the plate, for example by an additive manufacturing process of the plate. It is understood that in such an embodiment, the heat exchange between the dielectric fluid and the components 6 is carried out by convection by means of the plate.

Claims

Claims

1. Thermal regulation system for an electrical energy storage device (2), the electrical energy storage device (2) comprising a housing (4) and a plurality of components (6) to be thermally regulated housed in the housing (4) and aligned next to each other in a stacking direction, characterized in that the thermal regulation system comprises at least one plate (12) intended to be arranged between two adjacent components (6) to be thermally regulated, the plate (12) comprising at least one circulation conduit (18) for dielectric fluid comprising a main branch (28) and at least one secondary branch (30) participating in forming a passive non-return device.

2. Thermal regulation system according to the preceding claim, in which the at least one plate (12) comprises a first face (14) configured to come at least partly into contact with a first component (6) to be thermally regulated and a second face (16) configured to come at least partly into contact with a second component (6) to be thermally regulated, the at least one plate (12) comprising a thickness (20) which is defined between the first face (14) and the second face (16) and in which the at least one circulation duct (18) is produced.

3. Thermal regulation system according to the preceding claim, in which the at least one plate (12) comprises at least one imprint (22) participating in forming the at least one circulation duct (18), the at least one imprint (22) being open on at least one of said faces (14, 16) of the at least one plate (12).

4. Thermal regulation system according to the preceding claim, in which the at least one plate (12) comprises a plurality of impressions (22) open in regular alternation on the first face (14) and on the second face (16).

5. A thermal regulation system according to any one of the preceding claims, wherein the at least one plate (12) comprises at least two circulation ducts (18) extending in parallel to each other along a main circulation direction of the dielectric fluid between a fluid inlet (24) through which the dielectric fluid is able to enter the circulation duct (18) and a fluid outlet (26) through which the dielectric fluid is able to exit the circulation duct (18).

6. Thermal regulation system according to any one of the preceding claims, in which the at least one secondary branch (30) forms a bypass loop around an obstruction element (32), said secondary branch (30) comprising a first curved portion (34) connected to the main branch (28) in a first connection zone (31) and a second rectilinear portion (36) connected to the main branch (28) in a second connection zone (33).

7. Thermal regulation system according to the preceding claim, in which the at least one plate (12) comprises a plurality of obstruction elements (32) arranged laterally with respect to the main branch (28).

8. Thermal regulation system according to one of claims 6 or 7, in which the distance between the fluid inlet (24) and the first curved portion (34) is less than the distance between the fluid inlet (24) and the second straight portion (36), this distance being measured along the main circulation direction.

9. Electrical energy storage device (2) comprising a thermal regulation system according to any one of the preceding claims, in which at least one circulation duct (18) open on the first face (14) of the at least one plate is delimited at least in part by a first component (6) and at least one second circulation duct (18) open on the second face (16) of the at least one plate (12) is delimited at least in part by a second component (6).

10. Electrical energy storage device (2) according to the preceding claim, wherein the housing (4) comprises a lower wall (25) and an upper wall (27) between which the components are arranged, the at least one circulation conduit (18) being configured to allow the circulation of the dielectric fluid from an end edge of the at least one plate (12) facing the lower wall (25) of the housing (4) to an end edge of said plate (12) facing the upper wall (27) of said housing (4).

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