The present invention relates to the field of thermal management.
In particular, this concerns an assembly allowing the thermal management of a temporary heat producing element.
In an electric storage battery, it may be very useful to be able to regulate the operational temperature of cells which heat up when they produce current and which favourably must remain within a precise temperature range whatever the external temperature conditions even when the cells are stopped.
The term “battery” means “electrical device” and is therefore to be understood as any device that generates and/or converts and/or stores electricity, or as an “electrical device (or power supply system) that heats up and operates within a preferred temperature range that is important to manage”. Electrochemical devices are therefore concerned.
In this context, it is therefore conceivable that it may be necessary, depending on the situation:
Circulating at least one fluid in an assembly adapted to participate in this thermal management may then also be necessary.
There are such assemblies which have, for this purpose, fluid flow passages between two layers of material, between an inlet and an outlet for the fluid, so that thermal insulation—if the layers are thermally insulating—or thermal exchange—e.g. if the layers contain a PCM (an agreed name for a phase change material), for example, between a liquid and a solid—is achieved in relation to the fluid.
Thus, FR3015780 discloses the use of fluidic channels arranged in a PCM and allowing a circulation of a heat-transfer fluid, in particular a liquid. The fluidic channels are formed in a rigid block to hold them in place as the PCM phase change material changes to a liquid state. This is a fairly complex assembly to make. In addition, there is no indication of how the shape of the PCM layers or the “rigid block” to hold the fluidic channels in place might be achieved.
FR 3 060 863 discloses another solution where a module containing a phase change material is arranged between a first and a second electric battery cell, in thermal exchange with them. An air passage exists on both sides of the module, so as to allow air circulation between the first cell and the module and between the second cell and the module.
Amongst the problems that we wanted to solve here are the following:
A proposed solution to some or all of the above drawbacks and/or problems thus consists of an assembly comprising:
Alternatively, the aforementioned assembly shall be such:
In this way, real efficiency may be expected in the thermal management of the cells or groups of cells versus their optimal operating temperature range.
In the prior art, it has never been disclosed that, as proposed herein, a thermal management “assembly” or system of a battery, such as a storage battery, comprising three circuits (referred to above as “passages”) for thermal regulation, is implemented, at once:
In particular, the face along which the third circuit passes may be the bottom side of the battery (facing down).
Any of said “structure” may comprise a protective envelope (such as a plastic bag) containing the phase change material(s). This phase change material(s) may also be contained in a coating matrix, for example a rubbery one, avoiding in particular any leakage problem, even with solid/liquid phase PCMs.
It is further specified that, in the text:
Whether or not there is a structure with PCM, it is also proposed that, in order to finely regulate the battery temperature, avoiding both potentially destructive runaways and performance losses due to inappropriate temperature jumps, that:
Said fluid flow control means may further comprise:
This will lead to a finely controlled active thermal management of the battery.
The term ‘valve’ must be understood as any obturator allowing the passage or prohibiting the passage of a fluid in a conduit (solenoid valve, tap . . . ).
When applied in a vehicle arranged in an outdoor environment, the subject assembly may usefully be such that the valve-control means comprise:
In this way, the thermal management of the battery may be finely controlled, in a gradual manner, and the unnecessary use of fluid may be avoided.
For the same purpose, it may be foreseen that the said actions on the valves take into account:
In order to achieve the expected thermal efficiency of structures with PCM, it is proposed that in front of a cell, the or each structure is in contact with this cell, without ventilated circulation of fluid between them.
If the or each structure has a solid, continuous surface in front of the cells for non-discrete thermal exchange with them, such a ventilated circulation will be avoided.
If the assembly comprises, in said inter-cell space, at least two of said structures and at least one thermal insulator interposed between said at least two structures, the thermal transfers of the first and second cells between them will be effectively countered, thus avoiding a runaway of the system in case of overheating of one or of some cells.
Again, whether or not there is a structure with PCM, it is also proposed, in order to control the speed of action of the fluid concerned on the temperature of the battery, to circulate this fluid(s) only at certain times, when conditions are suitable. And a preferred solution proposed herein is also that the assembly comprises a device for supplying calories or frigories placed in thermal exchange with at least one of said fluids, upstream of the thermal exchange with the cells.
An alternative or complementary way of dealing with the same issue is for the said assembly to be such:
Thus, it will be possible to modulate the thermal exchange provided by these fluids. In particular, a gas and a liquid may be used respectively.
Yet another alternative or complementary way of addressing the same issue is that said peripheral fluid passage communicates with:
This will allow an economy of means, while being able to make the exchange temperature via the first and/or second passages dependent on that via said peripheral passages. It may then be preferred that the fluid flows first in the peripheral passages and then in said first and/or second passage(s), if both are provided, thereby maximising the overall exchange capacity at the level of the group of cells or the complete battery pack, before the fluid flows in the core, between two cells or two groups of cells.
Yet another possibility is that (a) in which more than one fluid would flow on the same side, in said first and/or second passages and/or in the peripheral passages; typically a gaseous fluid and a liquid on such a side.
This will further increase the thermal exchange on the same side and/or increase the compactness of the assembly.
It could also be foreseen to circulate the said fluids differently, depending on the moment.
For example, the above-mentioned passages could be used to circulate on the same side:
In other words, it may be expected that:
Since a goal of this type of “two-in-one” arrangement (multiple fluids passing along the same side) is efficiency in terms of thermal exchange performance, it may be advantageous for at least one of said multiple first or second fluid passages, or multiple peripheral fluid passages to be arranged in contact with a phase change material with which thermal exchange will occur when fluid is flowing. The PCM will enhance the performance of this exchange.
It is specified that this solution (see from (a) above) may be dissociated from the other aspects presented here and thus may be carried out independently of them. This is considered to be an innovation in and of itself (see also description of
In order to control in particular the consumption of the fluid circulating in the second passage(s), or even the use of this fluid in another circuit of the vehicle (such as its water circuit), it is also proposed that the said assembly comprises at least one recycling in which the second fluid passage will communicate with a recirculation circuit. Thus, it will be possible to reintroduce into the second supply (such as a water supply) at least part of the said fluid from the second fluid passage, after passing in the calories or frigories supply device.
In connection with this aspect of the first and second fluids being different from each other, gas/liquid for example, it may be of interest that the said fluid to be circulated in the second passage passes there between:
Thus, a large exchange surface is combined with a thermally efficient fluid.
Favourably, the (each) second fluid passage and said plates will be arranged under the electric battery, thereby limiting sealing problems due to a liquid fluid.
The invention will, if necessary, be understood in even greater detail from the following, non-limiting, description with reference to the attached drawings.
In these drawings:
As stated above and illustrated, one aspect of the invention relates to an assembly, with an arrangement that relates to an electric battery (or battery pack) 1 whose “core” thermal management is individualized:
Thus, depending on the case, the assembly includes:
In addition thereto, the assembly comprises (at least) a first fluid passage 17 or 117 in the space 15 or 115, located between said two opposing first sides facing each other, as the case may be:
The first passage 17 or 117 is connected to a first supply 27 of fluid to be circulated in thermal exchange directly between cells 10 or between groups 100 of cells.
Thus, for example, one of the first passages 17 or 117 will be connected to a first supply 27 of fluid to be circulated in thermal exchange with, and between, the first and second cells 11,13 (
In addition thereto, the assembly also includes (at least) a second fluid passage 19 or 119 located on:
It is understood that said second sides are different from said first sides. The second sides are side by side. They may typically be located in the same plane (see plan P
The second passage 19 or 119 is connected to a second supply 29 of fluid to be circulated in thermal exchange with the first and second cells or the first and second groups of cells.
In addition to or in place of the second fluid passage(s) 19 or 119, the assembly comprises (at least) one peripheral fluid passage 21 (
Thus, this (at least) one peripheral fluid passage 21 may extend along a plurality of walls 23, in particular three adjacent and successive peripheral walls or faces, such as 23c, 23e, 23d surrounding on a plurality of sides or faces the cells 10 or groups 100 of cells.
These walls or peripheral faces may be, laterally (for example vertically):
Another possibility:
Another possibility:
Indeed, at least a portion of the second fluid passage 19 or 119 on said second sides could be confused with at least a portion of the peripheral fluid passage 21 passing through the wall or face 23g; see
The peripheral passage 21 will be connected to an additional fluid supply 25 (inlet 25a, outlet 25b) to be circulated in thermal exchange with said cells 10 or groups 100 of cells.
The walls 23, functionalised with these internal fluid passages, may form a housing on two, three, four or five sides of the battery.
A priori, one will avoid functionalising in such a manner, with such passages, at least one face of the battery 1.
This should often be at least the upper horizontal face, marked 23h in
In this respect, it is specified that, as shown in
It should also be noted that, in
In addition to what has already been mentioned, the assembly of the invention also comprises (at least) a thermal insulator 33 (
The thermal insulation 33 will usefully be in the form of one or more panels, sheets or boards. The thermal insulation 33 may be a porous insulation. It may be placed in a pocket with a closed envelope 55 (
Thus, the thermal insulator 33 may usefully double at least two opposite sides of the battery pack 1, thus extending around the cells 10 or groups 100 of cells, overall; see
With two, three or four panels, sheets or plates of thermal insulation 33 on the two, three or four vertical lateral sides of the battery pack 1, and said peripheral passages 21 interposed between this thermal insulation 33 and the vertical outer lateral contour of the battery pack, the battery pack will be usefully protected from its external environment.
For the circulation of the fluid in the peripheral passage(s) 21, corner blocks or pillars 57 may be arranged at the corners, between two adjacent side panels of thermal insulation 33. Each corner block 57 incorporates one or more conduits 59 for individual connection to the opposing peripheral passage(s) 21. Each conduit 59 is curved so that the fluid passes the corresponding angle. Preferably, each corner block 57 should be made of a thermally insulating material (e.g. PU foam). In
Once the isolation and fluid circulation capabilities have been provided as above, a further aspect of the invention relates to the flow control of such fluid(s) via the first and, second and/or additional fluid supplies.
More precisely, it is provided for this purpose that the aforementioned assembly also comprises fluid flow control means 35 aimed at ensuring a circulation of fluid(s) in said thermal exchange:
It will be understood that these first and second time periods are moments included in the time during which the battery is active, i.e. in electrical charge and/or in electrical discharge, both of which may be concomitant.
For example, suppose a hybrid or electric vehicle 37 is started (
If it is a hybrid vehicle, there are two engines on board to move the vehicle: an internal combustion engine 36 and an electric motor 38. The battery pack 1 is at least connected to the electric motor 38 to operate it.
In normal operation, the cells of battery 1, for example, lithium-ion cells, which are used for the autonomous movement of the vehicle, will quickly lose energy (discharge during normal driving). For example, cooling air may then be drawn in, via a pump or a fan 41 (
As long as the temperature of the battery pack 1, as sensed by the temperature sensor 45, remains within a predetermined range (typically between 25 and 35° C., for example), the air in the battery pack 1 flows only in the peripheral passage 21 as fluid 25 (first time period). At the outlet, a valve 47 (such as a three-way valve) passes the air into a circuit 49 which sends it either to recycle (branch 51) or to the external environment EXT; branch 53, under the control 95 of the data processing unit 83.
If the temperature sensor 45 detects a temperature of the battery pack 1 above 35° C., for example, then at least two of the passages 17/117 and 19/119 will be activated: The fluid(s) flows 27 and/or 29 will thus intervene, increasing the thermal exchanges with the battery 1, in its immediate environment (second time period).
In this way, the chances of thermally managing the battery pack 1 are optimized.
As noted immediately above, the peripheral fluid passage 21, considered generally as a means for circulating fluid arriving through the power supply 25 around the battery pack 1, may be formed of a series of channels, as marked 210a, 210b, 210c in some of
This “peripheral fluid passage 21” may thus be defined:
The material of these panels, tubes or channels may be thermally neutral, or even thermally conductive, to promote thermal exchange with the battery 1.
However, it is possible to further refine the thermal management by using phase change materials (PCMs), as already mentioned.
Thus, in an embodiment as illustrated in
If provided, such a structure 61 will be usefully interposed between the battery pack 1 and the surrounding thermal insulation 33. Like it, the structure 61 may be presented as a series of panels, sheets or plates.
The PCM 65 may be dispersed in a rigid structural matrix 67, so as to form a self-supporting composite body, whatever the phase of the PCM (solid or liquid in particular).
The channels, tubes or spouts of the peripheral fluid passage 21 may be integrated (channels; see
With such an association between PCM, a circulating fluid (supply 25) and a thermal insulator around it, it will be possible to create a dynamic thermal barrier, the fluid allowing in particular to regenerate the PCM when the time comes.
Returning now to the thermal management via the second passage 19 or 119 (if any),
A thermally managed housing 71 may form the bottom 71a and at least some of the side walls in one piece. On the upper side, opposite the bottom 71a, an electrically insulating cover 72, which may comprise a layer of electrical insulation 33 and through which the electrical cables 73 pass, will usefully cover the terminals 31a, 31b 31a and close the housing 71 on this side.
In any case, said second fluid passage will usefully pass:
This second fluid passage 19/119 will be all the more interesting if, unlike the first passage 17/117 and peripheral passage 21, it may allow a liquid to circulate, such as water from the vehicle's water system 29 and therefore from a water source 69, as in the example of
All the more so with a liquid, the second fluid passage 17/117 will advantageously, together with said plates 67a, 67b or 67c, 67d, be arranged under the battery pack 1, as in the examples of
In the example of
In the example shown in
With respect to the thermally conductive plates, such as 67a, 67b (
Thus, the lower thermally conductive plate, such as 67b, may usefully serve (also) as a structural and/or anti-skid plate (see
The lower thermally conductive plate 67b will then be metallic.
Returning to the first passage(s) 17/117, it should be noted that the inter-cell space 15, or 115 between two successive groups of cells, may be more or less functionalised.
Thus, it may first be traversed, in its core, between two cells or groups of cells by one or more of said first fluid passage(s) 17/117.
As an alternative or as a complement, we may interpose:
If such structures 61 are provided, it is proposed, in order to promote thermal regulation via the PCM and as schematised in
If, in said space 15/115, thermal insulation 33 is interposed, it will be between at least two successive said structures 61, to counteract heat transfers between (groups of) cells.
The structural presentation of the assembly of the invention being essentially done, we will now present more the circuits which may integrate it and their functioning.
The presence, useful for the thermal management of the cells in view of their optimum operating temperature ranges, of devices for supplying calories or frigories 43 placed in thermal exchange with at least one of the said fluids, such as the exchangers situated therefore each upstream of the thermal exchange considered with the cells, has already been noted.
Thus, it will be possible to adapt the temperature of this fluid (supply 25 and/or 27 and/or 29) according to:
As an alternative or in addition to an exchanger, it is possible to provide, as a device 43 for supplying calories or frigories, at least one of a heating resistor, an interconnection with a vehicle air conditioning device 77, a dehumidifier 430.
Each circuit incorporating an assembly in accordance with the invention also comprises a plurality of valves 47 placed under the control of the aforementioned control means 35.
These valve control means 35 comprise, preferably in combination and connected to a unit 83 (see below):
A “third sensor” 97 is any means for acquiring the DOD and/or SOC of the battery (i.e. all or part of its cells or groups of cells), i.e. its charge level.
Thus:
Integrating this current over time will provide the net amount of Ah added or drawn to the data processing unit 83 (see below).
Each circuit integrating an assembly in accordance with the invention will in fact comprise a data processing unit 83, this unit being connected to said first and second temperature sensors 45, 79, to said third sensor 97, and to said means 81 for actuating the valves.
A relevant approach in terms of thermal management efficiency of battery 1, with anticipation, could then lead to at least some of the actions on the valves taking into account:
Thus, it will be possible to favour a predictive (anticipatory) management of the battery temperature during the said first period of time and, then, if this is not yet sufficient, to control the battery first from (at least) its temperature data, this during the said second period of time. Preferably, the data from the “third sensor” 97 for the acquisition of the DOD and/or the SOC will be provided continuously, whenever the battery is active, i.e. in electric charge and/or in electric discharge, both of which may be concomitant.
When the data processing unit 83 supplies the central computer of the vehicle with predictive management data anticipating a rapid recharging of the battery 1, for example at a motorway rapid recharging station, it may be provided that, a few minutes beforehand, the data processing unit 83 is controlled by this central computer to pilot a lowering of the temperature of the cells 10 of the battery 1 according to:
In order to reduce the temperature of the cells 10 while they are active, the data processing unit 83 will control at least one fluid flow in at least one of said first passage 17/117, second passage 19/119 and peripheral passage 21, thus during said first time period. And it may only be, if the software entered in the data processing unit 83 concludes that the temperature reduction at the end of this first period of time is insufficient with respect to a predetermined threshold that at least two of said first, second and additional fluid supplies will be controlled, thus during a said second period of time.
As already mentioned, it is provided in the invention that the fluid flow control means 35, which are adapted for regulating the flow of the fluid(s) involved, act to ensure a circulation of fluid in thermal exchange:
Even if there is no strict preference between the thermal exchanges to be established:
In this case, only in the second subsequent time period will the fluid(s) be made to flow in at least two of the passages 17/117 and 21, or 17/117 and 19/119, or 21 and 19/119.
And possibly in a third and still later period of time, one could circulate the fluid(s) in the three passages 17/117, 19/119 and 21.
Thus, a temperature criterion from at least one of the sensors 45,79 will prevail to initiate or even terminate each time period.
However, in order to prevent the effects of the external environment 39 as well as to avoid runaway of the battery pack 1 in case of overheating and/or to regulate it well in the preferred range of operation of the cells, it may be preferred, as illustrated in
As we understood it:
As preferred examples, four cases in particular are presented below in connection with
First, in the circuit 85 of
If we assume air as the fluid, this air is taken from the outside (EXT). The fan 41 circulates it to the device 43 and if necessary the dehumidifier 430.
In the device 43, the air receives calories or frigories, in thermal exchange with a fluid F2 (this has not been reproduced in the other figures, except
For example, if the sensor 79 detects an outside temperature (Tamb) of at least 30° C., it may be provided that a programmed activation of the power supply 25 at the input of the passages 21 is automatically recorded in the memory of the computer (or of the data processing unit 83), during therefore said first period of time, which may, for example, be the one allowing, later, when Tamb detected is 15° C. for example, to ensure a recharge of the PCM 65 and thus that it is in the solid state (assumption of an PCM 65 provided to pass from solid to liquid at about 25-28° C., and vice versa) before the outside temperature:
If the sensor(s) 45 now detect(s) a battery temperature (Tcell) of more than 29° C., it may be provided that two fluid supplies, such as those 27 and 29, or 27 and 25, are automatically activated during the said second period of time, which may, for example, be that which allows the temperature of the battery (Tcell) (or of at least one of its cells) detected by the sensor(s) 45 to fall back to below 27° C.
Note that this example could also be applied to “two-fluid” or “three-fluid” solutions, such as those shown in
In the solution of
In the solution shown in
Compared to the previous solution, the thermal management of the battery pack 1 via the power supply 25 at the inlet of the passages 21 (fluid F1) is carried out on a circuit 87 independent of that 85 of the power supplies and passages 27; 17/117 and 29; 19/119, which may remain identical to the previous solution of
On the independent circuit 87, one may find:
It will therefore be possible to dissociate the thermal exchange in the passages 17/117 and/or 19/119 from that in the passage(s) 21.
In the solution shown in
The independent circuit 87 (fluid F3, passage(s) 21) remains. The circuit 85 is split into 85a (fluid F1, passage(s) 17/117) and 85b (fluid F4, passage(s) 19/119).
Thus, on each circuit, a fan 41 circulates the fluid to the device 43 (thermal exchange with a fluid F2) and if necessary the dehumidifier 430. As supply 25, 27 or 29, at the inlet of the passages 21, 17/117, 19/119, respectively, the fluid F1 is thus admitted at a temperature adapted to the supply of calories or frigories expected for the thermal management considered at this stage.
On each circuit 85a, 85b, a three-way valve 47, controlled by the data processing unit 83, as already explained, directs all or part of the flow F1 or F4 to:
In
In one of the single or two-fluid circuits (see for example the single-fluid circuit 85; see
Thus, at least one double thermal exchange stage (in two successive passages among the passages 17/117; 19/119 and 21) may be associated with a common fluid.
The circulation of the fluid F1 or F3, (substantially) at the outlet temperature of the calories or frigories supplying device 43, initially in the passage(s) 21 (see the one-fluid solution, as in
If one prefers to circulate, always (substantially) at the outlet temperature of the calories or frigories supplying device 43, the fluid F1 first in the passage(s) 17/117 (see two-fluid solution, as in
It will have been noted that this situation will arise if, after the device 43, the fluid F1 is directed to the branch 93 of the circuit to flow first in the first passage(s) 17/117, then in the second passage(s) 19/119 before being recycled or expelled to the outside 39 (gaseous fluid) or recovered in a tank (liquid).
It should be noted in this respect that, in particular if the fluid F1, F3 or F4 is liquid, it will be advantageous for the second fluid passage(s) 19/119 to communicate with a recycling circuit, in order to reintroduce into the second supply 29 at least part of the said fluid coming from the preceding passage in this second passage(s), after passing through the device 43 for supplying calories or frigories.
As schematically shown as examples in
Upon exiting the passage(s) 17/117, the fluid concerned would either be recycled, back to the supply 27 to pass back into the first passage(s) 17/117, or directed to the supply 25.
In the examples described above in connection with the illustrations, only one fluid passes in the passages 17/117, 19/119 and/or 21.
However, a plurality of fluids may flow on the same side.
For example, the following may be provided:
Thus, if one may imagine:
The first fluid 56 will be one of the fluids of the first, second or said additional fluid supply 25,27,29. The second fluid 58 will be one of the additional fluids in these same supplies.
Since the first and second groups of passages 52, 54 do not communicate, the two supply fluids 56, 58 do not mix.
Thus, the two supply fluids 56,58 may be of different natures (air and glycol water, for example). The circulation may be controlled by the battery temperature (sensor 45, means 81 for actuating the valves and data processing unit 83, in particular). The combination of the two fluids or the use of one or the other may depend on the level of dissipation of the 10-100 cells which will induce a temperature rise.
It could be agreed that in normal operation, for example, only air may be circulated in the second group of passages 54 and that in critical operation (overheating) or rapid charging of the battery 1, glycolated water circulates in the first group of passages 52.
For the efficiency of the solution (increase in thermal exchange and exchange surfaces involved), at least one of said passages or group of passages 52, 54 is bordered by, and is thus in contact with, a phase change material 60 with which it is thus in thermal exchange when fluid is flowing.
In the example, two panels containing PCM 60 define, on two opposite sides, the respective upper and lower boundaries of a single fluid passage forming said second group of passages 54.
The first group of passages 52 is defined by a series of tubes arranged in parallel in the wall 50.
Different fluid supplies may flow through it without mixing.
The wall 50 may itself contain PCM, either as a substitute for or in addition to the PCM 60.
In
The valve 473 is located downstream of the calories or frigories supplying device 43 of the independent circuit 87.
The valves 470, 473 are controlled by the valve operating means 81 and by the data processing unit 83, as are the other valves 47.
Thus, in this example, and assuming the passage(s) 21 as corresponding to the second group of passages 54 and the wall 23 as corresponding to the wall 50 provided with the first group of passages 52, it will be possible to obtain
The assembly of
Number | Date | Country | Kind |
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1901534 | Feb 2019 | FR | national |
Filing Document | Filing Date | Country | Kind |
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PCT/FR2020/000031 | 2/13/2020 | WO | 00 |