System for supplying power to consumers of an electric or hybrid vehicle, and method for managing the power supply of such a vehicle

Abstract

The present invention relates to a system (1) for powering the equipment of an electric vehicle, the system comprising: - a battery (8) for powering an electric powertrain; - power switches (14, 16, 18) for connecting the battery (8) to the electric powertrain; - a DC-to-DC converter (4, 6) for powering an on-board network (50) when the vehicle is in operation, which DC-to-DC converter is connected at the input to the battery (8) and at the output to the on-board network (50); and - a DC-to-DC converter (2) for supplying the vehicle with power when it is in standby mode, which DC-to-DC converter is connected at the input to the battery (8) upstream of the power switches (14, 16, 18) and at the output to the on-board network (50); - a member (55) for detecting a current draw on the on-board network (50) capable of activating the converter (4, 6) when the vehicle is in operation.

Description

Description Title of the invention: Electrical power supply system for consumers of an electric or hybrid vehicle and method for managing the power supply of such a vehicle

[0001] The present invention relates to the fields of electricity and the automotive industry, and more specifically concerns an electrical power supply system in an electric or hybrid electric vehicle, intended to power the vehicle's equipment.

[0002] Electric or hybrid electric vehicles are very often equipped with a lithium-ion battery or equivalent technology, capable of supplying the energy necessary for an electric motor allowing the traction or propulsion of the vehicle, in possible cooperation with a thermal engine. Such a battery is called high voltage because the maximum no-load voltage at its terminals is generally much higher than that of service batteries, usually of the order of 12V (volts). However, some service batteries deliver a voltage of the order of 48V, this value can also be the maximum no-load voltage of certain "high voltage" batteries.

[0003] In an electric or hybrid electric vehicle, the service battery, often lead-acid, is used to power the vehicle's on-board network to which the vehicle's computers and low-voltage consumers such as windshield wiper actuators, sensors, or small heating resistors are connected. Since the service battery is generally more stable than the high-voltage battery, it also guarantees the power supply of vehicle safety devices such as braking and steering systems, while the high-voltage battery, which discharges more quickly, is intended to power the vehicle's electric motor, and possibly other high-voltage equipment such as an air conditioning compressor. The electrical network to which this equipment is connected is called the vehicle's "high-voltage" network.

[0004] The service battery only needs to be changed every three to four years, and is therefore used to power at least the vehicle's consumers during long periods of inactivity, i.e. when the vehicle is stationary and switched off. It is then said to be "asleep" because in reality during these periods of inactivity, the vehicle's computers have modules that remain activated to monitor the vehicle's environment, such as an alarm, a computer's communication module to receive radio signals from an ignition key, or messages from a remote server via a network of wireless communication, for example, requiring the sending of maintenance data or software updates. This consumption of vehicles during periods of inactivity is also set to increase over time, particularly due to the entry of vehicles into the Internet of Things.

[0005] However, anti-pollution standards will ban lead-acid batteries, which are also heavy and bulky, which will require, for example, replacing them with small lithium-ion batteries, which are very expensive and will need to be recharged very often when the vehicle is not in use, in particular by waking it up to connect a direct current - direct current converter to the high-voltage battery, the converter allowing the small lithium-ion battery to be recharged. This solution is energy-intensive due to waking the vehicle and the procedures for checking the high-voltage network before recharging the small lithium-ion battery.

[0006] The inventors have therefore designed an electrical power supply system architecture for an electric or hybrid vehicle, in which the vehicle's low-voltage consumers are powered by the vehicle's high-voltage battery, the latter integrating at least two direct current - direct current converters. One of them is intended to power the vehicle when it is "awake", for example when driving or in "on-board life" mode during which low-voltage consumers, such as a multimedia environment, can consume a low voltage of around 14V on the on-board network, and the other converter powers the on-board network when the vehicle is asleep, i.e. in "standby" mode. In order to have optimal efficiency and therefore consume little energy during this standby mode, this last direct current - direct current converter is sized to supply low currents.However, by sizing it to the strict minimum, this small DC - DC converter is no longer able to ensure a minimum voltage on the on-board network during transient phases which may correspond to a technical awakening of the vehicle or to an unforeseen overconsumption of current in standby mode, for example due to the triggering of an alarm. It is therefore preferable to use a medium-sized DC - DC converter to supply the on-board network in standby mode, i.e. capable of supplying more than a few Watts. However, such a DC - DC converter does not operate at its best efficiency outside of such transient phases, it involves an undesirable overconsumption of battery energy.

[0007] There is therefore a need to optimize the electrical architecture of an electric or hybrid vehicle, without a lead-acid service battery, ensuring the operation of the vehicle's safety equipment and making it possible to optimize the vehicle's energy consumption during long periods of disuse.

[0008] The present invention aims to remedy at least in part the drawbacks of the prior art by providing an electrical power supply system for equipment of an electric or hybrid vehicle and a method for managing the power supply of the on-board network of a vehicle equipped with such an electrical power supply system, which make the power supply of the vehicle's equipment more reliable, in particular during transient phases of the vehicle, while minimizing the consumption of the electrical power supply system.

[0009] To this end, the invention proposes a system for supplying electrical power to equipment of an electric or hybrid vehicle, comprising: - a battery capable of providing the energy necessary for the operation of an electric powertrain of the vehicle, - power switches capable of connecting the battery to the vehicle's electric powertrain, - at least one direct current - direct current converter, called an operating converter, capable of supplying an on-board network of the vehicle during operating phases of the vehicle, the operating converter being connected at the input to a first set of battery cells and at the output to the on-board network of the vehicle, - a direct current - direct current converter, called a rest converter, connected on the one hand at the input to a second set of battery cells upstream of the power switches and on the other hand at the output to the vehicle's on-board network, the rest converter being intended to supply the vehicle when it is in standby mode, - an operating converter control unit, powered by the vehicle's on-board network, and - a control unit for the rest converter, powered by the on-board network of the vehicle, the electrical power supply system being characterized in that it further comprises a member for detecting a current draw on the on-board network requiring activation of the operating converter, the detection member being capable of causing activation of the control unit of the operating converter when it detects such a current draw.

[0010] In the invention, the battery is capable of operating the electric powertrain, it is therefore a “high voltage” battery or traction battery, that is to say an electric accumulator battery powering an inverter and an electric motor when the vehicle is running, unlike a service battery of the prior art. The battery in the invention can therefore also be understood as a propulsion battery depending on the electric motor used, this being an electric motor allowing traction or propulsion of the vehicle, possibly actually in cooperation with another type of engine if the vehicle is hybrid, understood in the sense of “electric hybrid” in this application.

[0011] Furthermore, it should be noted that the terms "upstream" or "downstream" in this application refer to the relative position of electrical components or assemblies with respect to the direction of the current leaving the battery and heading towards the consumers of the vehicle. Thus, a first component is upstream of a second component if the current leaving the battery first passes through the first component and then the second component before returning to the traction battery, the latter being in discharge.

[0012] In the invention, the on-board network no longer needs to be powered by a service battery as in the prior art. Indeed, in the invention, whether the power switches are closed or open, the on-board network is powered either by the operating converter or by the rest converter.

[0013] More specifically, when the vehicle is in standby or "asleep" mode, the vehicle's computers are powered at least by the rest converter to allow them to receive, for example, activation messages only. For this purpose, the rest converter is connected upstream of the power switches, which allows it to always be powered by the second set of battery cells. It should indeed be noted that in the invention, the devices connected at the input to a set of battery cells are connected without an intermediate converter. In addition, since the control unit of the rest converter is powered by the on-board network directly at the output of the rest converter, its operation is secure.

[0014] When a vehicle supervision device, for example the vehicle's main computer, receives a message from an external server or a user request such as a request to unlock the vehicle, it reactivates, reactivates the other computers of the vehicle and the operating converter which in turn supplies the vehicle's on-board network during this entire phase where the supervision device is reactivated, called the operating phase. This may correspond to a vehicle driving phase or a "life on board" phase during which the vehicle is stopped but where a user can use, for example, a multimedia environment of the vehicle. The operating converter is connected to the battery upstream or downstream of the power switches, these then having to be closed during the entire operating phase in the latter case.Preferably the operating converter is connected to the battery upstream of the power switches to avoid this closure when the high voltage network is not otherwise used, this closure requiring safety checks.

[0015] Thanks to the invention, the rest converter can be dimensioned to the strict minimum for a nominal supply of the on-board network in standby mode. Indeed, in the event of overconsumption on the on-board network corresponding for example to a transient phase of waking up the vehicle, the detection device directly or indirectly activates the operating converter, which can then immediately take over from the idle converter and ensure the power supply to the various consumers of the on-board network, these consumers being able to include the vehicle supervision device. The activation of the operating converter corresponds to the waking up of its control unit, allowing the operation of the operating converter, therefore the conversion of current by the operating converter, as soon as the voltage of the on-board network measured by the control unit of the operating converter is lower than a voltage setpoint imposed by the control unit of the operating converter. The control unit of the operating converter is for example a microcomputer or a microcontroller.

[0016] While the control unit of the idle converter imposes a low regulation voltage, for example 12.5V, the control unit of the operating converter imposes a higher regulation voltage, for example 14V, allowing the nominal operation of the vehicle's computers. By allowing a lower operating voltage to be imposed in standby mode, the invention allows optimal sizing of the idle converter, with a nominal power of a few Watts for example, and therefore allows energy savings in standby mode as well as savings in material resources and space, the idle converter being smaller than the operating converter.

[0017] In particular, the idle converter is capable of supplying a maximum power to the on-board network less than or equal to a maximum consumption power of the on-board network when the vehicle is in standby mode. This maximum power is determined, for example, by averaging the power consumed on the on-board network during the entire duration of a standby phase of the vehicle and adding a safety margin. It is significantly lower than the power required when the vehicle is in an operating phase (driving or living on board, for example).Indeed, being used only in standby mode of the vehicle, the rest converter is for example sized to provide a few Watts, and at most between 10% and 30% of the nominal power of the on-board network, that is to say of the power consumed by the on-board network in nominal operation, measured for example by averaging the power consumed on the on-board network during the entire duration of an operating phase of the vehicle. The rest converter is therefore small, which allows savings in terms of material resources and energy consumption given that its best efficiency is at low power.

[0018] The detection device is, for example, a voltage comparator capable of comparing an on-board network voltage with a low voltage threshold, or a current comparator capable of comparing an on-board network current with a high current threshold. The detection device is, for example, integrated into the control unit of the rest converter, or is implemented independently of this control unit.

[0019] When the detection device is a voltage comparator, the low voltage threshold is preferably between 10.5 and 12V. This low threshold is of course a function of the voltage that the idle converter seeks to impose (for example 12.5V).

[0020] When the detection device is a current comparator, the upper current threshold is preferably between 0.2 and IA (amperes). This upper threshold is of course a function of the sizing of the idle converter (for example the maximum current delivered by the idle converter, which could be 0.2A).

[0021] In one embodiment of the invention, the first set of battery cells is identical to the second set of battery cells and comprises all of the battery cells. Thus, the operating and rest converters are each connected to the entire battery, which makes it possible to dispense with a specific balancing device for the battery cells.

[0022] Preferably, the electrical power supply system comprises two operating converters, each connected as input to all of the cells of the battery, or else connected as input one to the first set of cells of the battery and the other to a third set of cells of the battery, the first set and the third set forming a partition of at least part of the battery.

[0023] This feature ensures safe redundancy of the on-board network power supply during the operating phase, and in particular guarantees the power supply of safety systems such as a braking system or a trajectory control system. The operating converters also operate independently, in particular they each have a separate control unit, which means that in the event of a failure of one of the operating converters, this failure does not cause a malfunction of the other operating converter.

[0024] Each of the two operating converters is therefore controlled by a separate control unit, and the detection member is preferably capable of activating the control units of the operating converters when it detects a current demand on the on-board network requiring the activation of at least one of the operating converters. Thus, the two operating converters are activated at the same time, which allows them to respond to a high current demand, or to ensure the supply of power requested on the on-board network when one of the two operating converters is faulty.

[0025] The two operating converters are for example each connected upstream of the power switches, which means that the power switches do not have to be closed to use them and therefore to supply the on-board network, thus avoiding a safety verification procedure for the high-voltage network when no equipment is high voltage of the vehicle does not need to be powered. In an alternative embodiment, one of the two operating converters is connected to the input downstream of the power switches and the other of the operating converters is connected to the input upstream of the power switches. This alternative makes it possible to use the converter connected to the battery downstream of the power switches, to precharge the input capacitors or inductances of equipment such as a charger or an inverter for controlling an electric machine, before connecting this equipment to the battery. This means that a specific precharging system can be dispensed with, particularly if the power switches are power relays.

[0026] When the first set and the third set of battery cells form a partition of at least part of the battery, the first set and the third set preferably each comprise half of the battery cells. In this embodiment variant, a balancing device makes it possible to discharge each half of the cells in a quasi-identical manner, this balancing device being able to be software and consist of a current conversion by each of the converters over an identical duration, or so that they each supply the same quantity of energy to the consumers of the on-board network of the vehicle. Of course, other embodiment variants of the invention are conceivable, with for example more than two operating converters, each powered by all the battery cells or by a subset of battery cells, the subsets being able to form a partition of the battery cells.The first, second and third sets of battery cells may, in particular, be stacked entirely or in pairs, or form a partition of all the battery cells.

[0027] Preferably in the invention, each of the operating converters is capable of supplying a nominal power to the on-board network strictly lower than a maximum consumption power of the on-board network when the vehicle is in the operating phase. Thus, when the consumers of the on-board network consume little electrical energy, only one of the operating converters, consuming little operating energy (because they are optimized in their design for small loads of the on-board network, which is the most common case in the use of a vehicle), is used to supply the on-board network. For example, the operating converters are sized to each supply half of the maximum consumption power of the on-board network, which is the electrical power supplying the on-board network necessary for the vehicle to operate in all conditions.This maximum power is measured, for example, during a driving phase where all the on-board network consumers are activated, including the air conditioning, in extreme weather conditions. In another. For example, their respective nominal powers are between 50 and 90% of the maximum consumption power of the on-board network when the vehicle is in the operating phase. These are, for example, operating converters that can vary from 2kW up to 4kW (kiloWatt) of nominal power. Limiting them to 2kW instead of 4kW also saves hardware resources while ensuring the safety redundancy mentioned above. Of course, when the electrical power required by the consumers of the on-board network is greater than the maximum power that can be supplied by just one of the two operating converters, then the two operating converters operate simultaneously, the sum of the maximum powers of each of the operating converters being greater than or equal to the maximum consumption power of the on-board network when the vehicle is in the operating phase.

[0028] Furthermore, according to a preferred characteristic of the invention, the electrical power supply system according to the invention comprises an electrical energy storage member connected to the on-board network upstream of a low-voltage cut-off mechanism, such as a fuse box, to which consumers of the on-board network are connected. This energy storage member is for example a supercapacitor integrated in the battery pack according to the invention. It makes it possible to reduce the amplitude of current draws on the on-board network, and to smooth the current during transient phases such as in particular a switch to standby mode, in the operating phase or a change of operating converter to supply the on-board network. Alternatively, this energy storage member is a small lead-free battery such as a small lithium battery.The invention makes it possible to undersize this storage device by anticipating, thanks to the detection device, transient phases that consume a lot of current.

[0029] The invention also relates to a battery pack for an electric or hybrid vehicle, comprising a housing housing an electrical power supply system according to the invention, the battery pack comprising two high-voltage connection terminals and one low-voltage connection terminal. In addition to the advantages linked to the electrical power supply system according to the invention, the battery pack has the advantage of securing it, by electrically isolating the high-voltage components of the electrical power supply system from the chassis of the vehicle, and by protecting them from impacts. The operating converters and their controls are in particular protected in the battery pack, from the vibration and thermal stresses of the engine compartment. Optionally, when the electrical power supply system according to the invention comprises an operating converter downstream of the power switches, this is arranged outside the battery pack.Finally, when the power supply system according to the invention comprises two operating converters and one is dedicated to. the power supply of the safety systems, the other being dedicated to the power supply of non-safety systems of the vehicle, the battery pack has two low voltage connections, that is to say a low voltage connection for the power supply of the safety systems and the other for the power supply of the non-safety systems. It should be noted that the battery pack is also connected to the ground of the vehicle, to connect one of the outputs of each operating or rest converter.

[0030] The invention also relates to a method for managing the power supply of the on-board network of a vehicle equipped with a vehicle supervision device, capable of managing the consumption of vehicle equipment during operating phases, the vehicle being equipped with an electrical power supply system according to the invention, and / or equipped with a battery pack according to the invention, the management method comprising steps of: - power supply to the on-board network by the rest converter, F at least one operating converter being deactivated, - detection by the detection unit of a current demand requiring activation of the operating converter, - activation of the operating converter control unit, and - supply of power to the on-board network, via the operating converter.

[0031] The electrical power supply system according to the invention comprises means for implementing the management method according to the invention.

[0032] The invention finally relates to a vehicle equipped with an electrical power supply system according to the invention, integrated for example in the battery pack according to the invention. The vehicle further comprises a monitoring device capable of managing the consumption of vehicle equipment during operating phases.

[0033] Other characteristics and advantages of the invention will become apparent from the following description on the one hand, and from several examples of embodiment given for informational and non-limiting purposes with reference to the attached schematic drawings on the other hand, in which:

[0034] [Fig-1] represents an electrical power supply system according to the invention, for equipment of an electric or hybrid vehicle, in one embodiment of the invention,

[0035] [Fig.2] represents a first variant embodiment of the electrical power supply system of [Fig.l],

[0036] [Fig.3] represents a second variant embodiment of the electrical power supply system of [Fig.l],

[0037] [Fig.4] represents a device for detecting a current demand, integrated into the power supply system of figures 1, 2 and 3, and

[0038] [Fig.5] represents steps of a management method according to the invention, of the power supply of the on-board network of a vehicle equipped with the power supply system electrical of figures 1, 2 or 3.

[0039] According to an embodiment of the invention shown [Fig.l], an electrical power supply system 1 of an electric or hybrid vehicle comprises a battery 8 of electrical accumulators connected in series, these accumulators being for example cells using Lithium-ion technology. Of course other technologies can be used, for example that of Nickel metal hydride batteries. The battery 8 of the electrical power supply system 1 is a so-called traction battery, therefore “high voltage”, free of lead, the power of which allows an electric powertrain of the vehicle to operate. Its maximum no-load voltage is for example between 200V and 800V, in this embodiment.

[0040] The battery 8 is housed in a battery pack 3, which is a crash-resistant housing. The battery pack 3 has two high-voltage outputs 12 and 22 connected to a high-voltage network of the vehicle. In particular, the electric powertrain is connected as an input to these outputs, which are, on the one hand, a positive high-voltage connection terminal 12, connected to one end of the battery 8 via a fuse 15 and a positive power switch 14, connected in series, and, on the other hand, a negative high-voltage connection terminal 22, connected to the other end of the battery 8 via a pyroswitch 17 and a negative power switch 16, connected in series. The fuse 15 and the pyroswitch 17 are connected upstream of the power switches 14 and 16 respectively.A precharging system is also connected in parallel with the power switch 14, this precharging system comprising in series a precharging resistor 19 and a precharging switch 18. The precharging system makes it possible to avoid the formation of an excessively high current draw when the battery 8 is connected to a battery charger or to a charging terminal comprising input inductances or capacitors. Alternatively, in particular when the positive 14 and negative 16 power switches are produced by MOSFET transistors (for "metal-oxide-semiconductor field-effect transistor"), the electrical power supply system 1 does not comprise a precharging system and / or fuse devices 15, 17.

[0041] The power switches 14, 16, 18 as well as the precharging system and the fuse devices 15, 17 are elements of the electrical power supply system 1 which are integrated into the battery pack 3, which allows them to be electrically isolated in the engine compartment of the vehicle, and to protect them in the event of a crash.

[0042] In order to supply 14V to low voltage consumers of the vehicle, connected by electrical connections 92 to a fuse box 90, the electrical supply system 1 comprises, in the battery block 3:

[0043] - a first direct current converter - direct current 4 or first "operating converter", connected at the input in parallel to the battery 8 upstream of the power switches 14, 16, 18 and at the output to an on-board network 50 of the vehicle. More precisely, a first output of the first operating converter 4 is connected to a low voltage output 14V of the battery pack 3, this low voltage output 14V being connected to the on-board network 50, itself connected to the fuse box 90, and a second output of the first operating converter 4 is connected to a ground of the vehicle.

[0044] - and a second direct current converter - direct current 6 or second “operating converter”, connected as input in parallel to the battery 8 upstream of the power switches 14, 16, 18 and as output to the on-board network 50 of the vehicle. A first output of the second operating converter 6 is connected to the low voltage output 14V of the battery pack 3, and a second output of the second operating converter 6 is connected to the ground of the vehicle.

[0045] The first and second operating converters 4, 6 supply the on-board network 50 when the vehicle is "awake", i.e. in the operating phase. In this state, a supervision device 10 of the vehicle, for example a main computer, manages the consumption and activation of the various equipment of the vehicle, which may be low-voltage consumers such as a car radio or specific computers, as well as power devices such as an air conditioning compressor or an electric traction motor. In this embodiment of the invention, each of the first and second operating converters 4, 6 is sized to deliver 2kW in maximum operation, i.e. half of a total consumption on the on-board network 50, estimated at 4kW (these values ​​are a function of the vehicle equipment). In other words, the efficiency of each of the operating converters 4, 6 is optimal between 0 and 2kW.

[0046] The nominal power of each operating converter 4, 6 is thus substantially equal to half the power of a standard electric vehicle converter, and provides at most 2KW in nominal operation, i.e. for example 150 amps at 12.5V. This nominal power of a single operating converter 4, 6 is thus sufficient to power the safety systems of the vehicle and allow an emergency stop in the event of a breakdown, in particular it is greater than 1KW, and can provide at least 100A at 12.5V.

[0047] These choices allow for two operating converters that, in cost, volume and weight, save compared to two standard electric vehicle converters. Alternatively, each operating converter 4, 6 has a nominal power greater than 2kW but less than 3kW.

[0048] The rest converters 2 and operating converters 4, 6 being connected upstream of the power switches 14, 16, 18, the electrical power supply system 1 of [Fig.l] makes it unnecessary to close the power switches 14, 16 in order to be able to supply the on-board network 50 via the rest converters 2 or operating converters 4, 6.

[0049] To supply at least the on-board network 50 when the vehicle is in standby mode, i.e. when stopped without using vehicle equipment for an extended period, the electrical power supply system 1 also comprises in the battery pack 3, a direct current - direct current converter 2 called a "rest converter", connected at the input in parallel to the battery 8 upstream of the power switches 14, 16, 18 and at the output to the on-board network 50 of the vehicle. A first output of the rest converter 2 is connected to the low voltage 14V output of the battery pack 3, and a second output of the rest converter 2 is connected to the ground of the vehicle.

[0050] The idle converter 2 allows the vehicle's computers, through the low voltage it supplies to the on-board network 50, for example 1 IV, to receive requests triggering their awakening. Being intended for the vehicle's standby power supply, it is sized to supply a few tens of milliamps in nominal operation, or for example between 0.5 and 5 Watts. In other words, the efficiency of the idle converter 2 is optimized for a few Watts. Its operation is ensured by a control unit 20 powered directly at the output of the idle converter 2, therefore always activated. The control unit 20 is not subject to an external deactivation device, which contributes to the reliability of its power supply. The control unit 20 is for example a microcontroller.

[0051] In normal operation, the operating converters 4, 6 are activated during a transient wake-up phase of the vehicle, by the supervision device 10 which sends an activation message to corresponding control units 40, 60. The respective operation of each operating converter 4, 6 is in fact ensured by the respective control unit 40, 60 powered by the first output of the corresponding operating converter 4, 6, inside the battery pack 3 which secures these power supplies. The control units 40, 60 are for example microcontrollers.

[0052] The battery pack 3 integrates, in addition to the control units 20, 40, 60 of the rest converters 2 and operating converters 4, 6, a battery management module 32, monitoring, via sensors, the temperature and voltage of the battery cells. The management module 32 is in particular capable of opening the power switches 14, 16, 18 in the event of a fault in the battery 8. The management module 32 is hardware and software, and may in particular include temperature sensors and / or one or more pre-programmed electronic circuits.

[0053] The battery pack 3 has a CAN bus output 70 (from the English “Controller Area Network”) to which the control units 20, 40, 60 and the module are connected management module 32 of the battery 8. The CAN bus output 70 is connected to a CAN bus of the vehicle, to which the supervision device 10 is connected, which is located outside the battery pack 3. Thus the supervision device 10 can in particular send CAN messages to the control units 40, 60 to activate them in the transient phase of waking up the vehicle, or to deactivate them in the transient phase of putting the vehicle to sleep. The CAN bus also allows the supervision device 10 to communicate with the management module 32 when a user connects the vehicle to a charging terminal.

[0054] When the control units 20, 40, 60 are activated, each is capable of operating its respective converter 20, 40, 60 so that it supplies a low voltage current at its output when the voltage of the on-board network 50 is lower than a regulation setpoint voltage of the respective control unit 20, 40 or 60.

[0055] The regulation setpoint voltage of the idle converter 2 is for example 12.5V while the regulation setpoint voltages of the operating converters 4, 6 are for example each set at 14V when the power consumed on the on-board network 50 is greater than the maximum power of only one of the two operating converters 4, 6, therefore at 2kW. When the power consumed on the on-board network 50 is less than this value, the regulation setpoint voltage of one of the two operating converters 4, 6 is for example set at 14V while the regulation setpoint voltage of the other of the two operating converters 4, 6 is for example set at 13V so that only one of them operates at the same time.When low power is consumed from the on-board network 50, the operating converter 4, 6 in operation alternates, for example, every hour or at each new mission of the vehicle, a mission corresponding to the time period between waking up the vehicle and its subsequent falling asleep. The setpoint voltages of the two operating converters must be greater than the setpoint voltage of the idle converter.

[0056] The voltage of the on-board network 50 is measured independently by each control unit 20, 40, 60, for example the control unit 40 uses a voltage sensor 42 at the output of the first operating converter 4, and the control unit 60 uses a separate voltage sensor 62 at the output of the second operating converter 6.

[0057] The electrical power supply system 1 also comprises, integrated in the battery pack 3, a supercapacitor 24, for example of the DLC type (from the English “Double Layer Capacitance”), connected in parallel to the outputs of the rest converters 2 and operating converters 4, 6. This supercapacitor 24 makes it possible to smooth the current draws on the on-board network 50 while always guaranteeing a stable voltage on the on-board network 50, for example in the range 10.5V to 15V. The supercapacitor 24 also makes it possible to secure certain transient phases, which are for example the waking up or the vehicle falling asleep, or the moment between the occurrence of an electrical fault in one of the converters 2, 4, 6 and the melting of a fuse device internal to these components. The integration of this in the battery pack 3 makes it possible to secure the electrical power supply system 1, but also to simplify the electrical wiring of the electrical power supply system 1 and therefore its cost.

[0058] In this embodiment of the invention, the electrical power supply system 1 comprises a detection member 55 for detecting a current demand, capable of causing the activation, when the vehicle is in standby mode, of the control units 40 and 60 of the respective operating converters 4, 6. The detection member 55 is capable of causing this activation in the sense that it activates them directly or indirectly, by sending one or more messages or by applying a control voltage for example, the message or messages being intended for the control units 40, 60 or the supervision device 10. This activation takes place when the intensity of the current demand implies that the idle converter 2 will not be able to supply the power requested on the on-board network 50, and that at least one of the operating converters 4, 6 must therefore be activated.

[0059] For this purpose, the detection member 55 is directly connected to the control units 40 and 60 of the operating converters 4, 6 respectively, by a wired connection over which it can send CAN wake-up messages. Alternatively, this connection may be wireless. The detection member 55 is integrated into the battery pack 3 and possibly into the control unit 20 of the rest converter 2.

[0060] In another variant embodiment of the invention, the activation of the operating converters 4, 6 by the detection member 55 is done by sending a CAN message to the supervision device 10, which itself sends a wake-up CAN message to the control units 40, 60 of the respective operating converters 4, 6. In this other variant, the supervision device 10 activates only one of the operating converters 4, 6 or both converters 4, 6 depending on the power required on the on-board network 50.

[0061] In yet another alternative embodiment of the invention, the detection member 55 activates at least one of the operating converters 4, 6 not by sending CAN messages but by applying a control voltage to a switch of one of the control units 40, 60 of the corresponding operating converter 4, 6.

[0062] The detection member 55 therefore comprises a wired or wireless connection with the control units 40, 60 and / or with the supervision device 10. When the detection member 55 is implemented in the form of a voltage comparator, detailed later with reference to [Fig. 4], it is also electrically connected in parallel to the on-board network 50. The voltage comparator makes it possible to detect when the voltage on the on-board network 50 falls below a low voltage threshold set for example at 11.5V. The detection member 55 then sends an analog or digital signal to the control units 40, 60 to activate them, or to the supervision device 10.

[0063] When the detection member is implemented in the form of a current comparator, it comprises for example an input resistor connected in series to the on-board network 50, the voltage across the input resistor being compared to a reference voltage in the current comparator, to detect an intensity on the on-board network greater than a high current threshold, set for example to IA (ampere), corresponding to the maximum current that the idle converter 2 can supply with a safety margin of a few milliamperes. The detection member 55 then sends an analog or digital signal to the control units 40, 60 to activate them, or to the supervision device 10.

[0064] The activation of the operating converters 4, 6 by the detection member 55 allows the electrical power supply system 1 according to the invention to be robust to overconsumption on the on-board network 50 in standby mode, or to wake-ups of the vehicle involving unusual consumption on the on-board network, due for example to a computer programming fault preventing certain computers of the vehicle from going into standby or a computer programming fault unexpectedly waking up certain computers.

[0065] [Fig. 2] shows a power supply system 11 according to the invention, which is a first variant embodiment of the embodiment of [Fig. 1]. The power supply system 11 comprises elements common to the power supply system 1 which are referenced in the same way and not re-detailed. The components of the power supply system 11 are integrated in a battery pack 30 similar to the battery pack 3. The battery pack 30 differs only from the battery pack 3 in that it does not comprise a pre-charging system, and in that the second operating converter 6 is connected to the battery 8 downstream of the power switches 14, 16, while the first operating converter 4 is connected upstream of the power switches 14, 16. Thus in this first variant embodiment:

[0066] - when the vehicle is in standby mode, the on-board network 50 is powered by the rest converter 2 only,

[0067] - when the vehicle is awake but the power switches are open, the on-board network 50 is powered by the first operating converter 4 only, and

[0068] - when the vehicle is awake but the power switches are closed, the on-board network 50 is powered by the first operating converter 4 and / or the second operating converter 6.

[0069] In this first embodiment, the second operating converter 6 is reversible, i.e. capable of electrically supplying the high voltage network of the vehicle from the on-board network 50, which eliminates the need for a pre-charging system. Indeed, for example, when a charger with an input capacitor is connected to the high-voltage network, it must be pre-charged before closing the power switches 14, 16 if we want to avoid an electric arc that could stick these power switches, when these are electrical relays.

[0070] Thanks to this first embodiment variant, the second operating converter 6 uses the energy from the on-board network 50, supplied by the first operating converter 4, to precharge this capacity before the relays 14, 16 close.

[0071] In this first embodiment, the second operating converter 6 and its control unit 60 are preferably integrated into the battery pack 30 to secure them, but they may possibly be arranged outside the battery pack 30, for example for reasons of space requirement in the battery pack 30.

[0072] [Fig. 3] shows a power supply system 111 according to the invention, which is a second alternative embodiment of the embodiment of [Fig. 1]. In this second alternative, the elements common to the power supply system 1 are referenced in the same way and not re-detailed. The components of the power supply system 111 are integrated into a battery pack 300 similar to the battery pack 3. The battery pack 300 differs only from the battery pack 3 in that the battery is a storage battery 80 partitioned into two blocks 81 and 82 of electric storage batteries, between which a connection terminal called a midpoint makes it possible to split the power supply of the two operating converters 4, 6 into two independent power supplies.Thus the first operating converter 4 is powered by the block 81 by being connected at the input to the midpoint and to the end of the battery 80 connected to the positive high voltage connection terminal 12 via the fuse 15 and the positive power switch 14. The second operating converter 6 is powered by the block 82 by being connected at the input to the midpoint and to the end of the battery 80 connected to the negative high voltage connection terminal 22 via the pyroswitch 17 and the negative power switch 16.

[0073] The electrical power supply system 111 thus makes it possible to secure the power supply to the on-board network 50 by a redundancy of energy sources. Thus, in the event of failure of one of the accumulator blocks 81, 82, the on-board network 50 is powered by the other of the blocks 81, 82, which allows the safety systems of the vehicle to be functional while a driver of the vehicle parks it on the shoulder. The first and second operating converters 4, 6 are identical in this second embodiment, to allow balancing of the battery 80. In addition, the first and second operating converters 4, 6 each provide the same amount of energy to the on-board network 50 to enable this balancing, for example by alternating operation of the operating converters 4, 6.

[0074] [Fig.4] shows an exemplary embodiment of a voltage comparator used in the detection member 55 of the electrical power supply system 1, 11, 111. The voltage comparator comprises an operational amplifier powered by a positive voltage Vcc and a negative voltage -Vcc, the value Vcc being taken for example at 5V. These supply voltages are for example supplied by batteries or taken from the on-board network 50 using a divider bridge and a capacitor.

[0075] A reference voltage Vref of 8.5V is applied to the positive input of the operational amplifier, this reference voltage Vref being related to the vehicle ground and being supplied by a battery or taken from the on-board network 50 using a divider bridge and a capacitor.

[0076] The negative input of the operational amplifier is connected to a common terminal to a first resistor RI of 2k (Ohms) and to a second resistor R2 of 5k. The other terminal of the first resistor RI is connected to the low voltage output of the battery pack 3, 30, 300, i.e. to the on-board network 50. The voltage Vb between this other terminal of the first resistor RI and ground is therefore the voltage of the on-board network 50. The voltage Vb of the on-board network 50 is in this example of [Fig.4], of the order of 11.5V in standby mode.

[0077] The other terminal of the second resistor R2 is connected to the output terminal of the operational amplifier. The output voltage Vo between this output terminal and ground is therefore equal to:

[0078] Vo= Vcc = 5V as soon as the voltage Vb of the on-board network falls below (l+Rl / R2)Vref - Vcc*Rl / R2 or 9.9V

[0079] Then the output voltage Vo remains at Vcc = 5V and goes to -Vcc = -5V as soon as the voltage Vb of the on-board network becomes higher than (l+Rl / R2)Vref + Vcc*Rl / R2 or 13.9V.

[0080] The output voltage Vo of the operational amplification is converted by the detection member 55 into a digital wake-up signal, for example via an analog threshold. The wake-up signal has, for example, the value zero when the output voltage Vo is negative and the value 1 when the output voltage Vo is at 5V. This signal is multiplied by the value of a CAN message and transmitted via the CAN wire link to the control units 40, 60 of the operating converters 4, 6.

[0081] Finally, [Fig.5] presents steps of a method 100 for managing the power supply of the on-board network 50 during overconsumption on the latter while the vehicle is in standby mode. A first step E1 of the management method 100 is the supply of the on-board network 50 by the rest converter 2, the operating converters 4, 6 being disabled. The next step E2 is the detection of a current draw corresponding to a voltage Vb on the on-board network falling below a low voltage threshold, here 9.9V, by the detection member 55. In the embodiment variant using a current comparator, the detection of the current draw occurs as soon as the intensity on the on-board network rises above 1 A. The next step E3 is then the activation of the operating converters 4, 6 by the detection member 55, by sending a wake-up CAN message to their control units 40, 60 or to the supervision device 10, which in this case activates and sends such a wake-up message to the control units 40, 60. Finally, step E4 is the supply of power to the on-board network, by at least one of the operating converters 4, 6.

[0082] Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention. In particular, the characteristics of the different variant embodiments of the invention envisaged in this application can be combined to achieve the invention, insofar as these variants are not incompatible with each other.

Claims

Claims

1. Electrical power supply system (1, 11, 111) for equipment of an electric or hybrid vehicle, comprising: - a battery (8, 80) capable of providing energy necessary for the operation of an electric powertrain of the vehicle, - power switches (14, 16, 18) capable of connecting the battery (8, 80) to the electric powertrain of the vehicle, - at least one direct current - direct current converter (4, 6), called operating converter, capable of supplying an on-board network (50) of the vehicle during operating phases of the vehicle, the operating converter (4, 6) being connected at the input to a first set (8, 81, 82) of cells of the battery (8, 80) and at the output to the on-board network (50) of the vehicle, - a direct current - direct current converter (2), called a rest converter, connected on the one hand at the input to a second set (8, 80) of cells of the battery (8, 80) upstream of the power switches (14, 16, 18) and on the other hand at the output to the on-board network (50) of the vehicle, the rest converter (2) being intended to supply the vehicle when it is in standby mode, - a control unit (40, 60) of the operating converter (4, 6), powered by the on-board network (50) of the vehicle, and - a control unit (20) of the rest converter (2), powered by the on-board network (50) of the vehicle, the electrical power supply system (1, 11, 111) being characterized in that it further comprises a detection member (55) for a current draw on the on-board network (50) requiring the activation of the operating converter (4, 6), the detection member (55) being capable of causing the activation of the control unit (40, 60) of the operating converter (4, 6) when it detects such a current draw.

2. Electrical power supply system (1, 11, 111) according to claim 1, in which the detection member (55) is a voltage comparator capable of comparing a voltage (Vb) of the on-board network (50) with a low voltage threshold, or a current comparator capable of comparing a current of the on-board network (50) with a high current threshold.

3. Power supply system (1, 11, 111) according to claim 2, wherein the low voltage threshold is between 10.5 and 12V or the high current threshold is between 0.2 and IA.

4. Electrical power supply system (1, 11, 111) according to any one of claims 1 to 3, further comprising an electrical energy storage member (24) connected to the on-board network (50) upstream of a low-voltage cut-off mechanism (90), to which consumers of the on-board network (50) are connected.

5. Electrical power supply system (1, 11, 111) according to any one of claims 1 to 4, wherein the rest converter (2) is capable of supplying a maximum power to the on-board network (50) less than or equal to a maximum consumption power of the on-board network (50) when the vehicle is in standby mode.

6. Electrical power supply system (1, 11, 111) according to any one of claims 1 to 5, comprising two operating converters (4, 6), each connected at input to the set of cells of the battery (8, 80), or else connected at input one (4) to the first set (81) of cells of the battery (8, 80) and the other (6) to a third set (82) of cells of the battery (8, 80), the first set (81) and the third set (82) forming a partition of at least a part of the battery (8, 80).

7. Electrical power supply system (1, 11, 111) according to claim 6, wherein each of the two operating converters (4, 6) is controlled by a separate control unit (40, 60), and wherein the detection member (55) is capable of activating the control units (40, 60) of the operating converters (4, 6) when it detects a current demand on the on-board network (50) requiring the activation of at least one of the operating converters (4, 6).

8. Electrical power supply system (1, 11, 111) according to claim 6 or 7, wherein each of the operating converters (4, 6) is capable of supplying a nominal power to the on-board network (50) strictly lower than a maximum consumption power of the on-board network (50) when the vehicle is in the operating phase.

9. Battery pack (3, 30, 300) for an electric or hybrid vehicle, comprising a housing housing an electrical power supply system (1, 11, 111) according to any one of claims 1 to 8, the battery pack (3, 30, 300) comprising two high voltage connection terminals (12, 22) and a low voltage connection terminal.

10. Method (100) for managing the power supply of the on-board network (50) of a vehicle equipped with a vehicle supervision device (10), capable of managing the consumption of vehicle equipment in phases operating, the vehicle being equipped with an electrical power supply system (1, 11, 111) according to any one of claims 1 to 8, and / or equipped with a battery pack according to claim 9, the management method (100) comprising steps of: - power supply (El) of the on-board network (50) by the rest converter (2), the at least one operating converter (4, 6) being deactivated, - detection (E2) by the detection member (55), of a current demand requiring activation of the operating converter (4, 6), - activation (E3) of the control unit (40, 60) of the operating converter (4, 6), and - power supply (E4) to the on-board network (50), by the operating converter (4, 6).

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