Patent Grant
12237484
This application is a 35 U.S.C. § 371 filing of International Application No. PCT/FR2019/052012 filed Sep. 2, 2019, which claims the benefit of priority to French Patent Application No. 1857878 filed Aug. 31, 2018, each of which is incorporated herein by reference in its entirety.
The present invention concerns the field of thermal management.
In particular, it concerns a thermal management device (also called a thermal barrier) designed to promote temperature management in an internal volume which this barrier surrounds or borders, on at least one side, and/or with respect to a temporary heat-producing element disposed therein.
This applies in particular, especially on a vehicle, to pipes, ducts or hoses in which fluids, such as air or oil or a refrigerant (such as R1234 yf), circulate, or to electrical installations that thermal, such as electric storage batteries, or to engine parts whose temperature is to be managed:
In the present text the following meaning will be applied:
As PCM, one can find:
In a battery, it can be very useful to be able to regulate the operating temperature of the cells that thermal up when they produce current and that favorably must remain within a precise temperature range whatever the external temperature conditions are, even when the cells are at standstill.
In an air pipe connecting two hot zones of an internal combustion engine, for example, the temperature in the internal volume of the pipe may have to be regulated.
In an engine crankcase, after a cold start phase, evacuating or rather transferring calories can be useful.
In this context, it is therefore conceivable that it may be necessary, depending on the situation:
To circulate a fluid in a structure adapted to participate in this thermal management may then also be necessary.
There are such structures which have fluid circulation passages between two layers of material, between an inlet and an outlet for the fluid, so that, with respect to the fluid, thermal insulation—if the layers are thermally insulating—or thermal exchange—for example if the layers contain a PCM—is obtained.
In this case, a material, i.e. an element, having a solid phase at temperatures≤20° C. should be preferred.
Thus, FR3015780 discloses the use of fluidic channels arranged in PCM and allowing the circulation of a thermal transfer fluid, especially a liquid one. The fluidic channels are formed in a rigid block allowing them to be held in place when the PCM, phase change material, changes to a liquid state.
This is a rather complex assembly to fabricate. In addition, there is no indication of how the shape of the PCM layers and the “rigid block” to hold the fluid channels in place can be achieved.
Thus, among the problems that we wanted to solve here is the one related to the efficient realization of the structures, or assemblies, adapted to participate in a thermal management of the environment.
On this subject, FR3063137 discloses an assembly including:
In thermal contact with the battery, below it, a composite body thermal exchanger is, in FR3063137, arranged, together with the battery, in a housing whose characteristics are not specified. Only local thermal management (under the battery) is taken into account. No larger scale application is envisaged, which would imply the joint use of several so-called composite body thermal management elements having integrated depressions and thus a specific industrial implementation.
It is because of this thought that the present invention has thrived.
The present invention deals indeed with:
A solution proposed here thus consists in one said assembly as above, but which is further characterized in that:
The term “cooling plate” is to be understood as defining a thermal exchange means through which said (first) thermal exchange fluid is able to exchange thermal with the cells located in contact with this cooling plate.
The expressions “first sides” and “second sides” of the cells are to be considered as follows: the cells are identically oriented, parallel to each other, arranged in a line. In each case, therefore, one side is common to an entire group of stacked cells (even if the stack is flat); see
The case of prismatic cells will be a general case; it is the case of the examples below (except for the solution of
The first and second thermal exchange fluids may be the same or different; the same applies to the fluid flowing through the conduit(s) of the said PCM structures. One can thus imagine one and the same fluid circulating in series or in parallel in the above-mentioned elements.
In any case, the invention proposes to address the above-mentioned question of the thermal management of the battery cells rather than in the form of a plate placed under the battery, all in a “neutral” housing. Indeed, it is also with the external environment that it was decided to compose. Thus, it was decided to functionalize the case, and not the inside of it as in FR3063137, and to combine this with thermal exchanges without PCM via the (second) thermal exchange fluid. This will allow dissociation between functions:
The reluctance to apply to the housing (which defines the external footprint of the “battery zone”) an approach typically considered to be confined to the inside of the housing will have been overcome.
In addition, the way of thermally managing the battery, on one or more sides of a complete cell array, and creating a thermal barrier (with PCM and thermal insulation) around it is a departure from the conventional way known, while providing a significant advantage in terms of performance/weight/size.
In addition, the invention proposes to create the conduits crossing the PCM to circulate fluid therein:
Thus, it is proposed that the phase-change material (PCM) be present in a rigid structuring matrix, so that a self-supporting composite body is then formed regardless of the phase of the contained phase-change material, the composite body being shaped to locally present externally at least one depression that defines by itself a channel wall corresponding to the at least one conduit suitable for fluid flow.
Compared to the teaching of FR3063137, the advantage of obtaining rather fine and light elements will then have been amplified by applying it to a thermal barrier.
If the said blocks are corner blocks placed at the corners of the case, the fluid flow may usefully take place on several adjacent faces, or even on the entire circumference (a priori therefore on four faces) of the battery (i.e. the cells considered all together).
A modular approach for the industrial implementation of the solution has also been considered to make sense.
For the same purpose, it is also proposed that the structures should individually include a cover comprising:
It is also proposed that this cover should be shaped to present locally at least one elongated depression:
Since the question of the (first) composite body/cover connection may be critical, it is proposed that each composite body or pocket has lateral flanges for support of the cover, which can then be welded to the (first) composite body at the location of said flanges.
In this way, welding on the edges of the parts will be avoided a priori, thus facilitating and securing the composite body/cover connections.
Concerning welding:
In the above, it will have been noted that, in one case, the “channel wall” defined by each said depressions “could be suitable” for the circulation of a fluid. Thus, this is only one possibility. One may indeed prefer to interpose a sheath for the circulation of the said fluid which:
Even if respectively the intrinsic strength of the composite body and the internal partial vacuum contribute to the shape of the above-mentioned structure, the specific shape chosen should be of importance in achieving both a certain intrinsic stiffness and the definition of the fluid channels.
It is to this end that it is proposed that each self-supporting composite body or so-called pocket should have:
In the present solution, compared to FR3015780, there are no fluid channels arranged in PCM: the channels are separated from the PCM by the material of the composite body or even the cover. In fact, there is no longer any need for added structural elements to define the fluid channels in themselves, within a rigid intermediate structural element also added (which can also be dispensed with), nor is there any risk of altering the mechanical strength of the structure, which is self-supporting, if only because of the said depressions.
It should be noted that the above applies in the same way if, in the pockets, a thermal insulating material is placed, which may even reinforce the intrinsic strength of the vacuum pockets.
To all intents and purposes, it is at this stage:
In connection with the use of a rigid structuring matrix, it was sought to define solutions that satisfy the following problem: industrial mass production, reduced mass, easy and precise cutting for shaping at will, low cost, thermal performance (adapted thermal conductivity, especially in a “battery” environment), maintenance of the phase change material (PCM) in the matrix during the phase change of the material, possible use in a fluid(s) exchanger system, with capacity for the PCM to be not in contact with the fluid(s), in order to avoid dispersions when it is in liquid phase (or gaseous in the event that it is in one of its phases). The contact (interface) with the fluid(s) will then be ensured by the rigid structuring matrix,
Taking this problem into account, it is first proposed that the composite structure should include an elastomer or fibers, thus in addition to at least one PCM (and a priori preferably to a material with several PCMs changing phases at different temperatures). With an elastomer, one will benefit from a high deformation capacity, while the fibers will be used for their lower density and their important capacity of impregnation of PCMs.
In the composite structure option including (at least) one elastomer, it is proposed that the elastomer be selected from the following compounds: NR, IR, NBR, XNBR, HNBR, ECO, EPDM, EPM, CM, CSM, ACSM, CR, ACM, EVA, EAM, ethylene-acrylic acid copolymers, butyl rubber, halogenated butyl rubber and isobutylene-p-methylstyrene para-bromo-methylstyrene, with the addition of at least one of the following modifying agents: carboxylic acid maleic anhydride-grafted 1,2-vinyl polybutadienes or epoxidized and/or hydroxylated polybutadienes, silanes, ethylene-acrylic acid copolymers, maleic anhydride-grafted ethylene-propylene copolymers.
In this case, it will be a priori preferred that:
In the option composite structure including fibers, it is proposed that (at least) a graphite felt be used to take into account the above-mentioned problem.
Reverting to the question of the global thermal management of the battery with a functionalized box, it is also proposed:
Thus, it is on at least three different sides that the cell group in question will be in thermal exchange with PCM, or even with the fluid to be circulated through it.
It should be noted that the housing can also usefully define a thermal barrier:
In fact, the approach followed for the functionalization of the housing which is at the interface between the (internal) cells and the external environment allows the aforementioned assembly to form not, or not only, a thermal exchanger, as in FR3063137, but a thermal barrier, around one or several groups of cells, thus between this (these) group(s) and the external environment in which the vehicle equipped with the solution of the invention will evolve.
For this purpose, it will be useful to provide thermal insulating walls to line the outside of the said structures.
In particular, the thermal insulating walls will line the structures by being attached to them externally, or by the structures them externally.
Thus, the PCM (or preferably the different combined compositions of phase changing PCMs at different temperatures) will be present in particular to smooth out an excess of heat or cold coming from the outside environment, after said thermal insulating wall(s) have been traversed by the thermal flow directed from the outside (the environment) to the inside (said volume where the cells are arranged).
The invention will if necessary be better understood and other details, characteristics and advantages of the invention may appear when reading the following description made as a non-limitative example with reference to the appended drawings.
In these drawings:
and
A goal of the solution proposed here is thus the efficient realization of structures with thermal inertia (related to the presence of PCM) and/or thermal insulation (related to the presence of PIV type thermal insulation) implemented for environmental thermal management purposes, in particular a battery of accumulators.
In fact, structure 1 proposed for this purpose includes, as illustrated:
The composite body 3 and/or the pocket 9 are shaped to present locally at least one so-called depression (or hollow) 11 which defines by itself a channel wall 13 which may be suitable, or even intended, for the circulation of a fluid 15, it being then assumed that the channel created is then connected to a supply 17 and a recovery 19 of this fluid, which may be liquid or gaseous, see:
Fluid 15 can be either a thermal transfer medium or a refrigerant. It can be a liquid.
If, as shown in
In the figures, the elements marked as composite body 3 or pocket 9 or cover 21 can be interchanged.
Thus, in an assembly or a structure 1 provided with a cover 21, at least one of such elements may be presented as a plate, without a so-called depression, as shown in
For the connection with this cover, it is proposed that each composite body 3 or pocket 9 has lateral flanges 23 for a support of cover 21. Cover 21 can then be welded to the composite body or pocket at the location of the flanges 23. In this way, welding on the edges of the parts can be avoided, as shown in
From the above, it is clear that any shape that serves as a cover for the fluid channel 15 is suitable.
However, for the design of the covers, it may be preferable, as shown in
As previously, this additional composite body 30 and/or additional pocket 90 will then be shaped to locally complete and laterally close the wall 13 of the above-mentioned canal, i.e. each depression 11.
As already mentioned, this will be an interesting answer to the current difficulties to industrially produce in large series a structure allowing at the same time a fluid circulation and a packaging of either a vacuum or PCM.
In order to help achieve both a certain intrinsic rigidity and the definition of the desired fluid channels, it is also proposed that each composite body 3.30 or so-called pocket 9.90 present, as illustrated:
These slots and corners will also be well exploited by providing that, in order to laterally close each channel (i.e. each depression 11), the cover 21 and the self-supporting composite body 3 or pocket 9:
In pockets 9 or 90, a so-called thermal insulating material (see above) may usefully be placed 29, which may even reinforce the intrinsic strength of the vacuum pockets.
Concerning the choice in the realization of composite bodies 3,30, the following recommendations may be followed, in particular to meet the need to maintain the temperature of cells or housings of a battery for electric or hybrid vehicles; cf.
Indeed, lithium-ion cells in particular are strongly impacted by the temperature parameter. If this parameter is not taken into account, it can have serious consequences on the lifetime of the battery cells, on their performance (capacity and delivered power), on their stability and on the safety of use.
First of all, even if the liquid-gas and inverse change of state of PCMs is interesting in terms of the amount of energy involved, the preferred change of state in the targeted applications may be solid-liquid and inverse.
Then, to stay with the example of lithium-ion cells, the temperature range in which they must be maintained to operate optimally is between 25° C. and 35° C.
In addition, to stay with the example of lithium-ion cells, the temperature range in which they must be maintained to operate optimally is between 25 and 35° C.
However, in addition to the materials used for the elements participating in the thermal management and the layering of these elements in layers that can combine PCM and thermal insulation (see for example WO2017153691), it may be necessary to provide for a fluid circulation within this architecture, typically between two layers of materials; see channel 55 in this document.
To be able to circulate a fluid 15, with channels connected for example to an external air circuit, between the inlet/supply 17 and the outlet/recovery 19, will then be required, in a structure such as that 1 presented here.
In addition to achieving this with the above solution, we also wished to define a high-performance composite body, as mentioned above, since it is the very nature of this body that will ensure the criteria of thermal performance, self-supporting and ease of shaping or cutting expected.
Therefore, two solutions are proposed, respectively based on elastomer or fibers, each with several PCMs changing phases at different temperatures.
It should be noted that the phase change materials used in the formulation will then be favorably formulated in order to include them in matrices with a mass quantity of PCM in the formulation typically between 30% and 95%.
Formulations will preferably use microencapsulated or pure materials whose phase transitions can be included, for battery applications, between −10° C. and 110° C. (depending in particular on the electrochemistry, lithium-ion or not).
In the case of lithium-ion applications, microencapsulated PCMs with a mass percentage on formulated product of 35% to 45% can be used. These PCMs should be favourably embedded in a silicone matrix containing, in particular, flame-retardant and thermally conductive fillers.
In the first of the two above-mentioned solutions, matrix 7 includes (at least) an elastomer, which allows the body 3 to be adapted to situations that may require mechanical stressing or the monitoring of complex shapes (elastic aspect of the elastomer), with small masses.
In the second solution, the matrix 7 comprises fibers.
To take into account the above-mentioned problem, it is proposed to use (at least) a graphite felt, with graphite fibers.
In terms of implementation, several structures 1 could be installed between two adjacent cells and/or on different faces and periphery of the battery compartment to wrap it.
Starting from the surface of the battery compartment, four layers of phase-change material (several PCMs) can be provided, between which fluid 15 (e.g. air) may be circulated. On the outside of the PCM elements, the vacuum insulation is installed, typically one or more pockets 9 or 90. A thermally conductive peripheral envelope will allow the mechanical strength and protection of the system as a whole.
It should be noted that the above two solutions ensure that the PCM is not in direct contact with the fluid and that there is no leakage of PCM in the fluid state.
In general, a composite body solution such as the one described above will work dynamically: on an electric or hybrid vehicle, typically at a time of high demand, such as for example during a start under electric drive in winter (outside temperature of 3° C./4° C. for example) we will indeed be able to circulate air (coming from the outside) through the depressions which will allow this air to heat the PCM, said air having in passing recovered thermal energy on the cells of the battery. Air may then be redirected towards the outside environment. During its journey, the air will have both warmed the PCM(s) and evacuated excess heat from the battery cells. Another hypothesis: in winter, during cell operation, air cooled by an air conditioning circuit is projected towards the cells. This blown air then passes through channels 11.
Concerning the manufacturing of the composite bodies 3,30, it should be noted that they can be presented as plates comprising compressed fibrous graphite as a structuring matrix in which the PCM, which can be, or comprise, paraffin, is impregnated.
Graphite felts can be obtained by exfoliation. If there is an envelope, it will be thermally conductive (e.g. plastic foil). The impregnated matrix will not release PCM if it is not stressed. And to obtain a composite body with an integrated channel wall, the raw composite body can simply be molded or machined. The vacuum bag solution can be obtained by folding.
The alternative solution in
The alternative solution in
Elongated protrusions 47 may be on both large faces of the sheath if both panels or structures 3 or 9 and 21 are provided with depressions 11 (
The advantage of a sheath compared to a solution with independent tubes or plate 51, as shown in
The alternative solution in
In
The fluids F and 15 (or F1 and F2,
In an application such as a battery 33, where thermal management may concern both part of a whole (one cell of the battery) and the whole (all the cells of the battery), element 33.53 of the above solutions presented in connection with
It should also be noted that cover 21 or the additional element of a panel, or structure, 1 having a body 3 or pocket 9 may comprise a thermal insulating material that is not under partial internal vacuum (PU foam, for example), and therefore not PIV (see
The objective is to create a system that allows cooling, for example by forced air, of vehicle battery cells, by promoting their thermal management in their optimal operating temperature range, avoiding dead zones and non-homogeneous temperatures.
To this end, each plate 63 has a thickness (e) and on at least one of the faces 630, channels formed by the aforementioned depressions 11. These channels extend along the entire length of the surface concerned and open individually on two opposite sides of the tray.
In addition, between the channels 11, passages 65 are formed in the thickness (e) of the plateau 63 to receive external elements 67 (in this case the cells 64) to be placed in thermal exchange with the fluid F to be circulated in the channels 11. Thus, the external elements 64,67 to be stored are stored transversely to the plane P of each plate and the flow of fluid F circulates in this plane, over the largest possible surface.
Each tray can thus be defined by a molded PCM element integrating passages 65 and channels 11, which makes assembly easy (left view,
Typically, if the cells 64 are presented as a kind of “cylindrical stack” as illustrated, each tubular in shape, the trays will be favorably stacked, parallel, and resting on each other between channels 11 on the same side, so that one said tray 63 forms a cover for the adjacent tray 63, thus creating said channels with a closed section.
In order to increase thermal exchange, it is recommended that tray 63 include channels 11 arranged back to back, on the two opposite sides 630,631 according to the thickness (e) of each tray.
And for the positioning and maintenance of cells 64, the passages 65 pass through the entire thickness (e) of the trays 63 and the cells 64 are individually arranged in the successive passages 65 of the stacked trays 63 through which they pass. A lower support plate 69 can support the stack and the cells 64. It may be a cooling plate with additional channels 71 for the circulation of coolant, in thermal exchange with each cell 64, at its base 64a; right view
In the version of
In connection with a solution shown in
If WO2017153691 evokes the subject, the solution could be improved.
Thus it is first proposed here as an improved solution, as
The cooling plate 69 is relatively thermally conductive (e.g., metallic, such as aluminum) and has conduits (here internal) 71 that are connected to one said second supply 73 of a fluid to be circulated in said conduits 71, for surface thermal exchange with the cells 64′. On this subject, one notes that this is also provided for in the solution of
Moreover, in this solution, between two first opposite sides (respectively 641a and 641b,
If
The second fluid supply 73 will usefully be that of a liquid, such as water, because the sealing and connections are simpler to ensure than for the first supply 77. In addition, this will be more effective when there is “surface thermal exchange”. This second fluid supply 73 will also be usefully connected in a closed circuit, via a pump 81;
After exiting (in 83
The second fluid supply will usefully use a gaseous fluid, such as air. It is preferable that the circulation of this fluid in the assembly be forced (fan or other).
Once again, for a quality of thermal exchange and a well-considered optimization of the thermal management provided by these fluid circulations, in conjunction with the PCMs present, it is recommended that each composite body (3) or pocket (9) present, opposite the cells 64′ (but this can also apply, for example, to the 64′ cells of the previous solution), a solid (full), continuous surface, 645 for non-discrete thermal exchanges with the cells. It will have been understood that, on the contrary, a discrete contact is like separate zones without a continuum.
Thus, in the previous solution, surfaces 645 were formed by solid (full) cylindrical faces. In the solution of
Crossing the flows of the first and second fluids (always without mixing them) could further improve the efficiency of thermal exchanges.
Moreover, to counter the thermal transfers of one so-called cell 64′, it is proposed in the solution for prismatic cells (
In the solution in
The purpose of the electrical insulation sheets 91 is to avoid short circuits if the PCM of the composite bodies (3) or pockets (9) is electrically conductive. It is not obligatory to place this component, depending on the characteristics of the PCM but also on the desired effect: desired or undesired electrical insulation.
If electrical insulation sheets 91 are provided, it will be advantageous for the effectiveness of the electrical insulation that the contact surfaces between the elements 1,91,64′ are flat and continuous; hence the advice of flat surfaces on the two opposite sides of the electrical insulation sheets 91 and on the side of structure 1 (composite body 3 or pocket 9) facing the adjacent electrical insulation sheet 91; see
In
Thus, as above:
As in the other examples, the group of cells 64′ considered as a whole can thus be thermaled or cooled, depending on the temperature of the circulating fluid and the thermal gradient thus created between the cells 64′ and the fluid F.
It will have been understood that tubes 690 correspond to the aforementioned conduits or channels 71.
The tubes 690 may be parallel to each other, either per side or per group.
They may also be arranged facing only one side of a group of cells 64′ considered as a whole, as is the case for cooling plate 69 in the example in
In
In this solution, battery 33 comprises several assemblys or groups (here two 33a,33b) of cells. Groups 33a,33b of cells 64′ are aligned in an X direction. The cells 64′ each have electrical connection terminals 331 (anode/cathode).
As in the case of
Thus, around a group of cells taken together, the structures 1 including PCM will extend favorably on at least two opposite lateral sides (as on the sides shown in section
At the corners, if necessary, corner blocks 57 crossed by communication passages 59 can however be interposed each between two successive structures 1, to bring them together. The above-mentioned fluid F circulates there.
If necessary, along the relevant sides of the case, blocks 570, crossed by communication passages 590, may be interposed each between two successive structures 1, to join them. The above-mentioned fluid F will circulate there. Blocks 570 can be identical to the corner blocks 57 except for the orientation of the communication passages: axial orientation for those referenced 590, angled orientation for those referenced 59.
Another specificity of this solution is that it includes:
Thus, even if
In a solution with thermal management structures 1 (each comprising a composite body) and thermal exchange elements 340 (with or without cooling plate 69), the thermal exchange elements 340 do not contain PCMs: they are not thermal barrier elements but thermal exchangers arranged in “primary” thermal exchange with the cells: directly in contact with them or at least in thermal contact with them and interposed between them and the peripheral thermal management structures 1, except for those of thermal exchange elements 340a (
As illustrated in
Concerning the said thermal exchange fluid F, one can have several fluids F1, F2 that do not mix, viz.:
One can then imagine transposing the two-circuit solution illustrated in
Although the solution with integrated depressions 11 defining by themselves the channel walls 13 is very relevant (mass gain, simple manufacturing process, reduced thickness), structures 1 and/or thermal exchange elements 340/340a and/or cooling plate 69 could be realized, especially in thermal exchange situations with 64′ cells (as in the solutions presented in connection with
The fluid in question (F or F1 above-mentioned) could circulate in these conduits 350.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1857878 | Aug 2018 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/FR2019/052012 | 9/2/2019 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2020/044001 | 3/5/2020 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20120196157 | Krestel | Aug 2012 | A1 |
| 20140287292 | Baumgart | Sep 2014 | A1 |
| 20190210425 | Azzouz | Jul 2019 | A1 |
| 20190312322 | Ahn | Oct 2019 | A1 |
| 20200036067 | Mummigatti | Jan 2020 | A1 |
| Number | Date | Country |
|---|---|---|
| 106252787 | Dec 2016 | CN |
| 3015780 | Jun 2015 | FR |
| 3039561 | Feb 2017 | FR |
| 3040210 | Feb 2017 | FR |
| 3063137 | Aug 2018 | FR |
| 2013214354 | Oct 2013 | JP |
| WO2017153691 | Sep 2017 | WO |
| WO2018167382 | Sep 2018 | WO |
| Entry |
|---|
| Machine translation for CN 106252787 A. |
| Machine translation for JP 2013214354 A. |
| International Patent Application No. PCT/FR2019/052012, International Search Report and Written Opinion dated Jan. 28, 2020, 11 pgs. |
| Number | Date | Country | |
|---|---|---|---|
| 20210320344 A1 | Oct 2021 | US |
