FR2903056A1 - COMPACT POWER SUPPLY DEVICE FOR A MOTOR VEHICLE EQUIPPED WITH COOLING MEANS COMPRISING AN EXTERNAL COLD SOURCE - Google Patents

Abstract

The invention relates to a power supply device (10) for a motor vehicle, which is intended to connect at least one electric machine (12) to a battery (16) of the vehicle, and which comprises a single housing (32) in which is arranged at least one electrical energy storage unit (20), said housing (32) having a tray (34) for receiving at least one electrical energy storage unit (20), the device (10) ) having means for cooling the storage units (20), characterized in that the cooling means comprise: - a cold source (56) which is arranged outside the tank (34), - and means (58) , 70, 64) for transferring heat produced by the storage units (20) to the cold source (56).

Description

"Compact power supply device for a motor vehicle

  TECHNICAL FIELD OF THE INVENTION The invention relates to a power supply device for a motor vehicle, the invention more particularly to a power supply device for a motor vehicle, which is intended to connect at least one electrical machine to a battery of the vehicle, and which comprises a single housing in which is arranged at least one electrical energy storage unit, said housing comprising a receiving tray of at least one unit The device comprises means for cooling the storage units STATE OF THE ART Numerous examples of such devices are known, such power supply devices being used, for example, for the storage of electrical energy. supply of electrical machines of motor vehicles of electric and / or hybrid type, that is to say com an electric machine and a conventional combustion engine, for which it is important to be able to recover the kinetic energy in order to recharge the vehicle battery and supply the on-board electrical power network. This function is commonly called regenerative braking. A hydride metal battery is for example used. These power supply devices, however, pose many problems.

In fact, the energy storage units undergo numerous charging and discharging cycles. For example, when the motor vehicle starts, there is a very intense discharge of electricity. For example still, the storage units are charged with a high intensity electric current during periods of regenerative braking. When electric power is released, during discharge operations, or stored, during charging operations, the storage units give off heat. The amount of heat released is proportional to the intensity of the electric current flowing in charge or discharge. In addition, these charging and discharging cycles are likely to succeed at a very high rate, especially when the vehicle is driving in the city and the driver is brought to stop and restart the vehicle frequently. In order for the storage units to effectively store the electric current, they must be maintained within an operating temperature range which is bounded by a maximum operating temperature and a minimum operating temperature. When the charging and discharging cycles follow one another rapidly, the temperature of the storage units is likely to rise very quickly beyond the maximum operating temperature. The rise in temperature of the storage units is all the more rapid as the storage units are arranged in a closed container. SUMMARY OF THE INVENTION To overcome all these drawbacks, the invention proposes a power supply device for a motor vehicle of the type described above, characterized in that the cooling means comprise: a cold source which is arranged outside the tank, and means for transferring the heat produced by the storage unit or units to the cold source. According to other non-limiting features of the invention, taken alone or in combination: the means for transferring heat comprise at least one heat pipe of which a first heat-absorption end is thermally connected with the inside of the tank; and wherein a second heat dissipating end is thermally connected to the cold source; the first absorption end of the heat pipe is arranged inside the tank; the means for transferring heat comprise a heat propagation element, such as a plate, which is made of a heat-conducting material, a first heat-absorption part of the propagation element of the heat being thermally connected to the interior of the tank while a second heat dissipating portion of the heat propagating member is thermally connected to the cold source; the first absorption part of the heat propagation element is arranged inside the tank close to or in contact with the storage units; the second dissipation part of the heat propagation element is in contact with the first absorption end of the heat pipe; the cold source is a cold section of a vehicle cooling circuit; the cold source is an air conditioning duct of the vehicle; the cold source is a part of the chassis of the motor vehicle which is exposed to a current of air when the vehicle is traveling; 2903056 4 - the cold source is a finned heatsink; the finned heat sink is exposed to a fresh air current; the air flow is caused at least partly by a fan; - The air flow is caused at least in part by the air sucked during the driving of the vehicle. BRIEF DESCRIPTION OF THE FIGURES Other features and advantages will become apparent upon reading the following detailed description for the understanding of which reference will be made to the appended drawings, in which: FIG. 1 is a schematic diagram of FIG. FIG. 2 is an exploded perspective view of a first embodiment of a power supply device according to the invention, FIG. 3 is a view of a power supply device according to the invention; Figure 4 is an exploded perspective view showing an embodiment of the invention having a plurality of heat pipes. DETAILED DESCRIPTION OF THE FIGURES In the following description, like reference numerals refer to like parts or having similar functions.

FIG. 1 shows the assembly of a power supply device 10 for a motor vehicle produced in accordance with the invention. The device 10 is intended to connect at least one electrical machine 12 provided with sensors 14, capable of operating as an electric motor, for example to start the heat engine or even to drive at least one wheel of the vehicle and / or electric generator, for example to recover the kinetic energy of the vehicle during braking, to a battery 16 of the vehicle. This machine, such as an alternator-starter, is said to be reversible. This machine is taken as a non-limiting example for the rest of the description. As a reminder, it will be recalled that an alternator / starter is a reversible alternator making it possible, on the one hand, to convert mechanical energy into electrical energy when it is operating in an electric generator mode, in particular to recharge a battery and / or power the cells. consumers of at least one onboard network of the motor vehicle and secondly, to transform electrical energy into mechanical energy when operating in 20 electric motor mode, said starter mode, in particular to start the internal combustion engine or engine of the motor vehicle and, in one embodiment, prevent the engine from stalling, or even driving at least one wheel of the vehicle.

This alternator / starter comprises current rectifying means called inverter comprising, for example, MOSFET type transistors controlled by an electronic control and control unit as described for example in documents FR A 2 745 444 and FR A 2 745 445. .

This electronic control and control unit receives signals from sensors of the angular position of the rotor of the machine and also includes drivers, called drivers, which are power elements and which control the MOSFET transistors. These pilots, in one embodiment, belong to a power stage also comprising transistors of the MOSFET type of the inverter constituting a reversible AC / DC reversible electrical converter called AC / DC in electric generator mode. In electric motor mode, the MOSFET transistors of the inverter are controlled in all or nothing to control the windings of the stator of the machine in full wave or alternatively by a command with variable pulse widths, i.e. cutting technology called MLI (Pulse Width Modulation) or PWM in English. The control elements belong to a control stage of lower power. In one embodiment, the power stage is comprises an electronic power board carrying the power elements, such as the MOSFET transistors and the drivers, and the control stage comprises an electronic control card carrying the elements. control. In these documents, the alternator / starter is polyphase. In one embodiment, as described in the documents WO-A-02.108.334 and WO-A-03.088.471, the alternator-starter belongs to an arrangement for a motor vehicle comprising at least two energy storage units. electric. One of these storage units is a battery and the other a super capacitor, that is, a high-capacity capacity called Ultra Capacity. Note that in starter mode (operation in electric motor mode), the arrangement allows to feed the alternator-starter with a voltage greater than that in generator mode.

This type of arrangement makes it possible to recover energy during braking and comprises two electrical distribution networks, at least one switch or a circuit with two switches and a DC-DC converter, said DC / DC converter, allowing to convert voltages and operate at two different voltages. For more details we refer to these documents knowing that the inverter is a current electronic converter. Of course, the arrangement may use a rotating electrical machine such as a simple alternator electrically connected to a battery. In one embodiment, this alternator is associated with a starter connected in parallel with the alternator between a first terminal connected to ground and a second terminal connected to a circuit making it possible, in one embodiment, to put two batteries in series, for 12V example, to power the starter 24V at startup and to parallel these two batteries after starting the motor vehicle. The device 10 therefore comprises at least one electronic converter 18, 22 and a unit 20 for storing electrical energy. This device comprises two electrical networks, one dedicated to the power (the storage units 20 being in series) and 20 adapted to the energy recovery, the other dedicated to the energy to notably recharge the battery 16 connected to the power supply. network of the vehicle and / or power this network. In a first non-limiting embodiment, the device 10 comprises a DC-DC converter 22 of voltage. In a second nonlimiting embodiment, the device 10 comprises an inverter 18. The inverter is a DC / AC reversible converter. It operates as an AC / DC converter when the machine is in electric generator mode (it is often called a rectifier bridge), and as a DC / AC converter when the machine is in electric motor mode.

In a third nonlimiting embodiment, the device 10 comprises an inverter 18 and a DC-to-DC converter 22. In a fourth embodiment, in the nonlimiting exemplary embodiment which has been represented in FIG. the device 10 comprises three electronic converters, namely an inverter 18, a DC-DC converter 22, and in addition a bi-position switch 30 or two switches 30, which are interconnected by power connectors such as io bus bars (not shown). The inverter 18, in the abovementioned manner, is a reversible AC / DC reversible electrical converter called "AC / DC" in electric generator or DC-AC mode called "DC / AC" in electric motor mode.

The DC-DC converter 22 makes it possible in particular to convert a voltage on the energy storage unit side 20, said voltage being in a range of values, here in a nonlimiting manner between 6V and 35V, at a voltage compatible with that of the battery 16, the battery supplying an onboard network for example of the order of 12 volts. The bi-position switch 30 or the two switches 30 make it possible for them to determine the operating mode of the electric machine 12. In the example taken, the generator mode comprises two phases: a so-called alternator phase, and a phase energy recovery mode, the engine mode comprises a startup phase and dynamic assistance. The mode of operation of the machine with a bi-position switch is as follows: the switch connects the inverter 18 and the storage unit 20 in the motor mode, and in the energy recovery phase, 2903056 9 - The switch connects the inverter 18 and the battery 16 in the alternator phase. Note that in another embodiment, there is no switch.

The device 10 is for this purpose connected by cables 24 to the electrical machine, by cables 26 to the battery, and by cables 28 to a power supply network of the vehicle. The device 10 for recovering the kinetic energy of the vehicle using the electric machine, this architecture 10 is more particularly known under the name of architecture "14 + X". As illustrated in Figures 1 and 2, the device 10 comprises a single housing 32 in which are arranged the (s) electronic converter (s) 18, 22 and the (s) unit (s) 20 is storage electrical energy in particular to reduce the lengths of connectors between these elements, so as to limit the effects of the link inductances. In general, the housing 32 has a lower portion 34 forming a tray 34 for receiving one or a plurality of electrical energy storage units 20. This lower part 34 is completed by at least one upper part 36, covering the lower part 34, and receiving at least one control electronic card 38 and at least one power electronic card 40 which comprises the electronic converter (s) ) 18, 22, 30, that is to say the inverter 18, the DC-DC converter 22, and the bi-position switch 30. More particularly, the lower portion 34 has the shape of a first substantially parallelepipedic tray , open at its upper end 42, which receives at least two electrical energy storage units 20 "supercapacitors" or Ultra capacitor connected in series.

In a first example of storage units 20 are arranged In a second mode of storage units 20 are arranged 5 In a third mode of storage units 20 are arranged According to the dimensions of the storage units 20, the best arrangement will be chosen three modes to optimize the space required for electronic components integrated in the housing 32, here in the example in the direction of the height. In a first variant applicable to the three modes, the energy storage units 20 are arranged in stages, the units 20 of a first stage being offset with respect to the second stage so that two units 20 of the second stage are in tangential contact with the same unit 20 of the first stage. The contact can be direct or indirect. In a second variant applicable to the three modes, as shown in FIG. 2, the lower part 20 receives axial alignments 44 of electrical energy storage units 20 which are arranged in the longitudinal direction. , but this provision is not limiting of the invention. The alignments 44 of electrical energy storage units 20 could indeed be arranged in the width direction. The energy storage units of two adjacent alignments are maintained by holding means 46. Any embodiment of these holding means may be suitable for the proper implementation of the invention. In the figures, the holding means are composed by elastic collars 46, but they could be forms integrated with the lower part 34, or even electric energy storage units 20 themselves, each of those it then comprising interlocking means intended to cooperate with the neighboring unit 20. non-limiting embodiment, the in the direction of the length. non-limiting embodiment, in the sense of the width. non-limiting embodiment, the in the direction of the height.

The units 20 have in the embodiment of Figure 2 a generally cylindrical shape of circular section. Of course alternatively these elongate units 20 have another section for example of polygonal shape, such as a hexagonal section. In a variant, the section is oval. The upper part 36, when it has a second tray 48 which caps the upper end 42 of the first tray 34. The bottom of the second tray is here made of a thermally insulating material to prevent the transmission of heat io to the first tray 34. This second tray may in particular be carrying external connectors, for example a connector 23 for receiving control signals and a connector 25 for receiving a power supply.

The second bin 48 is open at its upper end 50, and is intended to receive successively, preferably from bottom to top of the tank 48, the electronic control board 38, an insulating gasket 52, and the electronic card. 40, which includes the inverter 18 and the DC-DC converter 22, and a cover 54 which covers the upper end 50 of the second tank 48. This cover 54 comprises upper cooling means. Preferably, the power card 40 is arranged closer to the upper cooling means. Thus, this arrangement avoids heating the storage units 20 by the heat released by the power board. The storage units 20 arranged in the first receiving pan 34 are able to release heat. This heat accumulates in the first tank 34 which is closed by the upper part 36, which has the effect of causing an increase in the temperature inside the first tank 34 and thus of all the storage units 20.

According to the teachings of the invention, in order to maintain the temperature of the storage units below a maximum operating temperature, the first tank 34 comprises cooling means.

The first tray 34 more particularly includes associated lower cooling means for providing group cooling of the electrical energy storage units 20. FIG. 3 shows diagrammatically the first tray 34 in which the electrical energy storage units 20 are arranged. The first tank 34 is closed, thus the heat released by the storage units 20 accumulates in the first tank 34 thus increasing the temperature inside the first tank 34. The cooling means of the storage units 20 comprise a a cold source 56 which is arranged outside the first tank 34 and means 58 for transferring the heat released by the storage units 20 to the cold source 56. Thus, the first tank 34 may comprise walls made of thermally thermally insulating material. insulating. The term "cold source" designates any thermal potential whose temperature is lower than the maximum operating temperature of the storage units and whose thermal capacity is infinite. More generally, the cold adjective will refer to any element whose temperature is below the maximum operating temperature of the storage units 20. In the example shown in FIG. 3, the cold source 56 comprises a finned dissipator 60 which is advantageously made of a metallic material and which dissipates the heat by convection. The dissipator 60 is here made of aluminum. The convection may be natural or forced for example by a fan 62 as shown in FIG.

In the example shown in FIG. 3, the cold source 56 is arranged in a zone remote from the first tank 34. According to a variant represented in FIG. 4, the cold source 56 is arranged in contact with the first tank 34. 5 fan 62 is for example fixed to the tray 34 by screwing. According to a not shown variant of the invention, the cold source 56 is formed by a portion of the chassis of the vehicle which is exposed to a stream of air when the vehicle is traveling. For example, the air is conveyed to said part of the chassis by a so-called "boa" pipe, a first end opening of which is arranged longitudinally forwards under the vehicle while a second opening is arranged facing the vehicle. said part of the frame. According to yet another variant not shown, the 1s cold source 56 comprises a cooling pipe of the engine of the motor vehicle. According to another variant, the cold source 56 comprises a cooling pipe for cooling the motor vehicle. The means for transferring heat here comprise a heat pipe 64 having a first heat absorbing end 66 thermally connected to the interior of the first tank 34 and having a second heat dissipating end 68 thermally connected thereto. The first absorption end 66 is more particularly arranged inside the first tray 34. It is here associated with a heat propagation element 70 which is made of a heat conducting material. Here the heat propagation element 70 consists of a heat propagation or diffusion plate 70. The propagation plate 70 is arranged in the first tank 34 near the storage units 20. The plate 70 is more particularly arranged above the storage units 20 and its dimensions are such that it covers all the storage units 20.

In a variant not shown of the invention, the propagation plate 70 is arranged in contact with one or more storage units 20. The first absorption end 66 of the heat pipe 64 is arranged in contact with the plate 70. Thus, the plate 70 is capable of accumulating the heat produced by all the storage units 20 so as to conduct the heat up to the absorption end 66 of the heat pipe 54.

According to a variant not shown, the heat pipe 64 is replaced by a rod of heat conducting material which is for example made integral with the propagation plate 70. The rod thus transfers the heat accumulated in the propagation plate 70 until at the cold source 56 by the heat conduction. According to a variant of the invention shown in Figure 4, the first tray 34 is provided with several heat pipes 64 which are arranged in the walls of the first tray 34 so as to surround the storage units 20. Thus, each heat pipe 64 does not The heat generated by only a part of the storage units, for example one or two storage units 20, is discharged. In the examples shown in FIGS. 3 and 4, there is no provision for a second tank 48, the electronic part of the tank. Figure 2 being deported. Thus, the presence of the second bin 48 is not required. In Figure 4, the first tray 34, of generally parallelepiped shape, has cavities 134 for housing in the manner of bottles of the units 20, here in the form of "super capacitors".

In the example shown in FIG. 4, the cold source 56 comprises here a deflection plate 160 which is interposed between the finned dissipator 60 and the tank 34. The deflection plate 160 is advantageously made of a conductive material of 2903056 heat. The deflection plate 60 is more particularly arranged in contact with the dissipation end 68 of the heat pipe 64. The deflection plate 160 comprises air deflectors 161 which guide the air blown by the fan 62 laterally to the outside. . Thus, the air blown by the fan 62 is heated by the dissipation ends 68 of the heat pipes 64. This heated air is constantly ejected far from the tank 34 by the baffles 161 to be renewed by fresh air. The invention is not limited to the examples cited in the description. Thus, the heat transfer means 58 may also include a cooling fluid circuit or any other known means for transferring heat from inside the first tank 34 to the cold source 56. In addition, the propagation 70 is not necessarily a plate. This propagation element 70 may be for example in the form of "L" or "U". In addition, it is possible to equip the tank 34 with a plurality of heat transfer means 58 which are each thermally connected to the same cold source 56 or to separate cold sources 56. The invention advantageously makes it possible to arrange the cold source outside the housing 32 so as to reduce its bulk. In addition, the invention makes it possible to cool the storage units 20 by taking advantage of existing but unexploited cold sources in the motor vehicle, such as a chassis or body part of the vehicle. In addition, thanks to the invention, the tank 34 can be closed in a sealed manner because there is no need to ventilate the storage units 20 to cool them.

Claims (13)

  1. Device (10) for powering a motor vehicle, which is intended to connect at least one electric machine (12) to a battery (16) of the vehicle, and which comprises a single housing (32) in which is arranged at least one electrical energy storage unit (20), said housing (32) having a tray (34) for receiving at least one electrical energy storage unit (20), the device (10) comprising means for cooling the storage units (20), characterized in that the cooling means comprise: - a cold source (56) which is arranged outside the tank (34), - and means (58, 70, 64) for transferring the heat 1s produced by the at least one storage unit (20) to the cold source (56).   2. Device (10) according to any one of the preceding claims, characterized in that the means for transferring heat comprise at least one heat pipe (64), a first end (66) of heat absorption is thermally connected with the interior of the tray (34), and a second heat dissipating end (68) of which is thermally connected to the cold source (56).   3. Device (10) according to the preceding claim, characterized in that the first end of absorption (66) of the heat pipe (64) is arranged inside the tray (34).   4. Device (10) according to claim 1, characterized in that the means for transferring heat (58) comprise a heat propagation element (70) which is made of a heat conducting material, a first part of absorption (70) of the heat of the propagation element (70) being thermally connected to the interior of the tank while a second heat dissipating portion of the plate is thermally connected to the cold source ( 56).   5. Device (10) according to the preceding claim, characterized in that the first absorption part of the propagation element (70) is arranged inside the tray (34) near or in contact with units storage (20).   6. Device (10) according to the preceding claim taken in combination with one of claims 2 or 3, characterized in that the second dissipating part of the propagation element (70) is in contact with the first end of absorption (66) of the heat pipe (64).   7. Device (10) according to any one of the preceding claims, characterized in that the cold source (56) is a cold section of a cooling circuit of the vehicle.   8. Device (10) according to any one of claims 1 to 6, characterized in that the cold source (56) is an air conditioning duct of the vehicle.   9. Device (10) according to any one of claims 1 to 6, characterized in that the cold source (56) is a part of the chassis of the motor vehicle which is exposed to a stream of air when the vehicle rolls.   10. Device (10) according to any one of claims 1 to 6, characterized in that the cold source is a heatsink fin (60).   11. Device (10) according to the preceding claim, characterized in that the finned heatsink (60) is exposed to a stream of fresh air.   12. Device (10) according to the preceding claim, characterized in that the air stream is caused at least in part by a fan (62). 2903056 18   13. Device (10) according to any one of claims 11 or 12, characterized in that the air stream is caused at least in part by the air sucked during the rolling of the vehicle. 5