FR3078455A1 - POWER SUPPLY MODULE FOR ELECTRIC VEHICLE ENGINE, WITH THERMAL TRANSFER - Google Patents

Abstract

Power module for an electric vehicle engine (1), characterized in that it comprises: - an electric accumulator (3); a reversible switch bridge (13) connected to the electric accumulator (3); a housing (23) enclosing the elements of the power supply module; - A thermal transfer device between the electric accumulator (3) and the bridge (13) of switches, the heat transfer device being disposed in the housing (23).

Description

Title: Power supply module for electric vehicle engine, with thermal transfer

The invention relates to the power supply of electric vehicles. It relates more particularly to systems making it possible to accumulate energy in these vehicles then then to restore it for, in particular, the propulsion of the vehicle.

Electric vehicles generally have an electric accumulator in the form, for example, of a battery pack. This electric accumulator can be recharged by a source of electrical energy external to the vehicle. With a sufficiently charged electric accumulator, the electric vehicle can power its propulsion means, generally comprising one or more electric motors.

The electric vehicle undergoes charging phases of the electric accumulator and propulsion phases, where the accumulator supplies the propulsion means of the vehicle.

To supply its propulsion means as well as to charge the electric accumulator, the electric vehicle generally comprises a charger which is a converter from an alternating voltage to a direct voltage and which allows the charging of the accumulator from a network. electric, during the charging phases, and an inverter which is a converter from a direct voltage to an alternating voltage which allows the supply of the propulsion means from the accumulator, during the propulsion phases. For certain vehicles, certain parts of these converters are pooled to gain volume, mass and cost.

Patent application FR2738411 describes an electrical power supply system for an electric vehicle, which comprises an inverter supplying the electric motor of the vehicle from a battery. When the inverter is not in service, switch means present in the inverter are used to form an AC-DC converter receiving as input a single-phase AC voltage and delivering a DC voltage for charging the battery, which allows the battery to be charged from the single-phase alternating voltage.

Patent application EP0553824 describes an electrical system for an electric vehicle which comprises an inverter allowing the control of the electric motor of the vehicle from a battery, and also allowing the charging of the battery from an alternating voltage supplied from the side of the inverter's alternative stage. This document also describes the use of the vehicle’s electric motor windings as inductors used in charging the battery by the inverter.

Patent application FR2946473 describes an electromotive assembly, in particular for an electrically propelled motor vehicle, comprising a multiphase electric motor, a storage battery, an inverter capable of converting the direct current of the battery into multiphase alternating current suitable for supplying the engine , and a connection box which alternately makes it possible to supply the motor from the battery, to charge the battery directly from a single-phase network, and to charge the battery from a multi-phase network.

The invention aims to improve the power supply of electric vehicles.

To this end, the invention relates to a power supply module for an electric vehicle engine, comprising:

- an electric accumulator;

- a switch bridge connected to the electric accumulator;

- a box containing the elements of the power supply module;

- a thermal transfer device between the electric accumulator and the switch bridge, this thermal transfer device being arranged in the housing.

The expression “electric vehicle” designates any vehicle adapted to be propelled at least partially and at least during certain phases, by an electric motor. This expression includes in particular exclusively electric vehicles, hybrid vehicles, electrically assisted vehicles, whether they are land, sea or air vehicles, intended for a particular use or for the transport of loads or passengers.

The switch bridge forms a reversible charger and inverter device adapted on the one hand to charge said accumulator from an external source of electrical energy and adapted on the other hand to convert the electrical energy of the accumulator for the power supply to an electric vehicle engine.

The electric accumulator can be any type of device making it possible to accumulate electric energy within an electric vehicle and to supply this energy to a traction motor during the driving phases. The electric accumulator can be a storage battery or a cell pack, for example a lithium-ion or lead-acid battery pack.

The invention provides temperature conditioning of the electric accumulator making it possible to limit its temperature excursion despite variations in the temperatures of the environment. The temperature of the accumulator is kept within the temperature range limiting aging, both in the traction and charging phase.

Electric accumulators such as battery packs are devices with a limited operating temperature range. For lithium ion batteries, for example, the ranges can be from -10 ° C to 60 ° C in discharge and from 0 ° C to 45 ° C in charge. At low temperatures, the conductivity of the electrolyte decreases, the internal resistance of the battery increases and the usable capacity decreases. Landfill performance is affected accordingly. For charging at low temperature, below 0 ° C and up to 5 ° C conventionally, there is also the risk of deposit of lithium metal on the graphite of the negative electrode. The normal reaction for inserting lithium into the carbon-based material of the negative electrode has a potential close to that of transforming the lithium-ion into lithium metal in the form of a deposit of lithium metal on the surface of the 'electrode. This parasitic reaction degrades the battery, decreases its capacity and its lifespan. The acceleration of aging of lithium-ion batteries at high temperature, from 35 ° C conventionally, is well known. The acceleration of aging by the low temperature charge phases has at least as great an impact, especially if fast charges at low temperatures are desired. The invention uses the heat losses from the accumulator and those from the switch bridge to increase the temperature of the module. The invention also uses the heat capacity of the entire power module. It is not necessary to start cooling as long as the temperature of the thermal transfer device does not reach a high temperature setpoint level.

On the side of the switch bridge, the cooling of the latter is shared with the temperature maintenance of the battery. The slow or fast charge can be carried out without external cooling, and therefore without ventilation noise for example, the heat released is simply stored in the form of an increase in the temperature of the electric accumulator. External heat production is therefore rarely necessary in such a vehicle, unlike vehicles of the prior art, some of which consume considerable energy to keep the batteries in their optimal temperature range in cold weather. Only if the temperature of the battery becomes too high will cooling be necessary. This is an advantage over vehicles of the prior art which generally require the switching circuit cooling circuit to be started for all charging phases. The use of cooling devices (for example by ventilation) remains necessary for certain phases, but it can be minimized during the charging phase.

A cooling circuit, associated with the heat transfer device, can therefore be provided for the phases where the temperature becomes too high for the accumulator. It is also possible to add powerful cooling to the heat transfer device, both for the accumulator and for the bridge components of the switches, in cases of use with high power charging and / or discharging. Depending on the use and the climate, it can be direct air cooling with a fluid / air exchanger or heat pump cooling in order to limit the temperature of the module to a value below the temperature of available air.

By using a dielectric fluid in the heat transfer device, a very high dielectric strength (a few continuous kilovolts, even a few tens of kilovolts) can be obtained between the components of the accumulator and the vehicle mechanics, as well as between the components of the switch bridge and vehicle mechanics, without degrading the heat transfer allowing these components to be cooled. The use of a dielectric fluid also makes it possible to very greatly reduce the parasitic capacitances between the parts of the switch bridge subjected to a strong voltage front and the surrounding mechanical parts as well as between the filtering inductance and the mechanics. The reduction in these parasitic capacities results directly in a drop in the common mode conduction currents to be processed by the EMC filtering devices.

Safety is reinforced with regard to the risk of thermal runaway of the accumulators by limiting the rate of rise and the amplitude of the rise in temperature of an accumulator in the event of a fault thereof. Safety is also reinforced with regard to the risks of thermal runaway of the accumulators by limiting the temperature to which the accumulators located near a faulty accumulator are subjected, which implies minimizing the risk of propagation of the '' thermal runaway of accumulators step by step.

Thanks to the invention, it is not necessary to resort to a water plate on which the switches are mounted and making it possible to cool the bridge, as is common in the prior art. This water plate of the prior art generally creates parasitic capacities which are here avoided.

The power supply module can include the following additional characteristics, alone or in combination:

- The thermal transfer device comprises at least one sealed enclosure in which is contained a dielectric fluid which bathes the electric accumulator and the switch bridge;

- the power supply module comprises a set of coils connected to the switch bridge, these coils also being immersed in the dielectric fluid;

- The housing forms said sealed enclosure;

- Said sealed enclosure comprises a sealed enclosure arranged around the electric accumulator;

- Said sealed enclosure comprises a sealed enclosure arranged around the switch bridge and communicating with the sealed enclosure arranged around the electric accumulator;

- the supply module includes a device for the circulation of the dielectric fluid;

- the sealed enclosure arranged around the electric accumulator comprises a thermal insulator;

- the power supply module includes a heat transfer stop system;

- the switch bridge is reversible, being adapted to control both the charging and discharging of the electric accumulator;

- the power supply module has an external hydraulic connection allowing heat exchange with other elements of the vehicle;

- the external hydraulic connection is connected to a cooling device.

Another object of the invention is a power pack for an electric vehicle, comprising a plurality of modules as described above and in which the dielectric fluid circulates from one module to another by the external hydraulic connection of each module.

The power pack may include the following additional features, alone or in combination:

- one of the modules is suitable for heating the fluid;

- the power modules are not cooled during the power supply to the engine;

- the power pack includes at least one charging terminal allowing the pack to be connected to an electrical network, the external hydraulic connection being associated with the charging terminal, and the dielectric fluid also bathing the charging terminal.

Another object of the invention is a power supply module for an electric vehicle engine, comprising:

- an electric accumulator;

- a switch bridge connected to the electric accumulator;

- a device for controlling the switches of the switch bridge;

- a set of coils connected to the switch bridge;

- a box containing the elements of the power supply module, this box being provided with a set of external connections which comprise: a motor supply terminal block provided with the same number of output connections as the number of coils in the set coils; and a synchronization output connected to the switch control device of the switch bridge.

Another object of the invention is a power pack for an electric vehicle, comprising:

- a plurality of modules as described above;

- a power bus comprising conductors, each terminal connection output of each module being connected to one of said conductors;

a synchronization bus to which the synchronization output of each module is connected, so that the device for controlling the switches of the bridge of each module is connected to the synchronization bus.

The invention provides modular power supply for the propulsion means of an electric vehicle, as well as the charge of the electric accumulators of this vehicle. In a vehicle equipped with a set of such modules, each module has its own electric accumulator as well as its own converter allowing both the charging of the electric accumulator and the supply of an electric motor of the vehicle.

The synchronization output of the power supply modules allows each of these modules to synchronize the voltages and / or currents delivered on the voltages and / or current of the other modules. All the modules thus ensure, in common, the delivery of a controlled voltage (for example a sinusoidal motor control voltage) for the supply of a traction motor of the electric vehicle or the delivery of a controlled current. (e.g. direct current) for charging the electric accumulator by absorbing a controlled current from the source of electric energy.

An electric vehicle can be provided with several modules according to the invention to ensure the accumulation of electric energy necessary for the autonomy of the vehicle, and to ensure the supply of this electric energy to at least one electric motor of the vehicle. This modular nature allows easy integration into different types of vehicles by dividing the total volume required for the accumulation of electrical energy and for engine control into modules. The different modules can be positioned in the different possible housings of the vehicle by making the best use of the space available in the vehicle.

The number of modules can be adapted to a particular vehicle in an initial configuration, depending on the needs for electric accumulator capacity and / or power to be supplied for the traction of the vehicle. This number can be changed over time, when the vehicle configuration is changed, by adding or removing modules afterwards.

In addition, the modules can be reused for a second use as part of a second life, for another type of vehicle or for a stationary application. For this second use, the electrical energy storage and the converter of the vehicles are reused in a second use, and not only the energy storage according to standard state-of-the-art solutions.

Preferably, the modules together provide a sinusoidal voltage at a frequency adapted at all times to the motor drive, when used in traction. They supply or absorb sinusoidal currents at the grid frequency when connected to the grid for grid support or battery charging. Synchronization of several modules is thus facilitated.

The traction function of the vehicle, that is to say of supplying electrical energy to the motorization of the vehicle, benefits from the modular nature provided by the invention thanks in particular to the advantages listed below.

As the electrical storage function is made modular, the storage capacity can be increased by multiplying the modules with minimum cost and in a simplified way if we compare, for example, to the parallelization of batteries, which requires special and complex attention. In addition, the traction function effectively adapts to this variation in the accumulation capacity.

In the same way, as the power supply function of the electric motor is made modular, the power supplied to the motor can be increased by the multiplication of modules with minimum cost and in a simplified way if one compares, for example, to the change from an inverter to a more powerful inverter.

The modular nature provided by the invention also guarantees fault or fault tolerance both of an electrical accumulator and of a switch bridge used as an inverter, since a set of modules according to the invention continues to perform its function as long as that one of the modules remains functional.

The inclusion of coils in the power supply module allows a traction motor of the electric vehicle to be supplied by slowly varying electrical voltages (for example, variations less than 100 V / ps and preferably close to a sinusoidal voltage), instead of supplying it, as is the case in the prior art, by chopped voltages, that is to say by the voltages with fast switching edge (for example voltages with variation of l '' order of 1 kV / ps to a few tens of kilovolts per microseconds) coming directly from a switching bridge of an inverter.

Since the motor is supplied by smoothed voltages and not chopped voltages, the stray capacitances of the motor windings are not crossed by current peaks at each voltage front of the switch arms as is the case for the classic solutions according to the state of the art. These switching peaks are conventionally very high levels of electromagnetic disturbances in current conducted in the wires which have to be treated.

Furthermore, since the total traction power is delivered by several modules, the powers to be switched in each switch bridge are lower, the parasitic capacities of the switching arms and of the smoothing inductors vis-à-vis the surrounding mechanical parts are lower which minimizes the size and cost of the filters necessary to ensure the electromagnetic compatibility of this equipment.

Likewise, the distribution of powers in different modules leads to increased safety with regard to electrical risks.

The charging function of the vehicle's energy accumulators also benefits from the modular nature provided by the invention thanks in particular to the advantages listed below.

The charge is made modular because the electric accumulator of each module is provided with its own charging device. Within a set of modules, each module can therefore recharge its accumulator according to the most suitable strategy. Charging strategies can be multiple, for example:

- all the modules charge their respective accumulator together when a large charge power is available (case of the electric vehicle connected to a high power terminal);

- the modules charge their respective accumulators sequentially (one after the other) when a low charge power is available (case, for example, of the electric vehicle plugged into a domestic electrical network of a dwelling), the management of the queue of modules for the load being ensured by virtue of the synchronization output and this sequential load prevents the tripping of the differential switches of the installation;

- only one or more modules charge their accumulator, the accumulators of the other modules not being charged (case, for example, of a degraded operating mode with a limited charging time or a limited amount of electrical energy).

An electric vehicle equipped with such a set of modules can therefore be provided with a plug, or any other system for connection to the electrical network, which can be dimensioned as accurately as possible and which can in particular be simplified, with a mass, a volume and reduced cost.

Furthermore, the invention makes possible the direct connection of the switch bridge to the electric accumulator because the disconnection from the outside can be ensured by a relay at the output of the power supply module. This relay can be included in the module or be placed right out. This arrangement eliminates the need for a preload circuit and internal contactors between the switch bridge and the electric accumulator. Precharge circuits are devices used in the prior art and necessary to manage the recharging of the capacities of an equipment when it has been disconnected from an electric accumulator. These precharge circuits are here eliminated since, within a module, the accumulator is permanently connected to its switch bridge. A precharging device will only be necessary when the inverter is first connected with its filtering capacitor to the storage device or during the maintenance phase requiring these two parts to be disconnected. Such a preloading device is then a tool for mounting in the factory and for maintenance operations and no longer a device integrated into the vehicle.

The power supply module can include the following additional characteristics, alone or in combination:

- the switch bridge is directly connected to the electric accumulator;

- the set of coils is directly connected to the switch bridge;

- the power supply module further comprises, between the set of coils and the motor power supply terminal block, a capacitive filtering stage;

- the power supply module also comprises, between the set of coils and the motor supply terminal block, at least one relay comprising a relay contact for each output connection of the motor supply terminal block;

- the switch bridge is reversible, being adapted to control both the charging and discharging of the electric accumulator;

- each coil in the coil set is connected to the midpoint of an arm of the switch bridge.

The power pack may include the following additional features, alone or in combination:

- the power pack includes a charge switch connected on the one hand to the power bus and on the other hand connected to at least one charging terminal for connection to an electrical network;

- the power pack includes an external synchronization module connected to the synchronization bus and controlling, from the switching of the bridges, the synchronization of the voltages and / or current which are supplied or absorbed by each module;

- alternatively, one of the modules is declared as master commanding module, from the switching of the bridges, the synchronization of the voltages and / or of the current which are supplied or absorbed by each module;

- the modules are synchronized so that the power pack delivers a sinusoidal motor control voltage;

- the modules are synchronized so that only some of the modules deliver a sinusoidal motor control voltage;

- the modules are synchronized so that modules deliver a sinusoidal motor control voltage and so that the electrical accumulator of only one of the modules is discharged to the maximum;

- the power pack also includes a battery management system whose indicators are readjusted when the electric accumulator of only one of the modules is discharged to the maximum;

- the modules are synchronized so that one of the modules carries out intercellular balancing of its electric accumulator, while being supplied by at least one other module;

- the modules are synchronized so that they sequentially recharge their respective electrical accumulators.

A preferred embodiment of the invention will now be described with reference to the accompanying drawings in which:

- Figure 1 shows power supply modules of a vehicle, according to the invention;

- Figure 2 illustrates the voltages delivered to the motor in the assembly of Figure 1 in the case where the smoothed voltages are perfectly sinusoidal;

- Figure 3 is a variant of Figure 1;

- Figure 4 illustrates a variant for the power modules of Figure 1;

- Figures 5 and 6 show examples of the filtering stage of Figure 1;

- Figure 7 shows a heat exchange device for the modules of Figure 1;

- Figure 8 is a variant of the heat exchange device of Figure 7.

FIG. 1 illustrates an embodiment targeting an electric vehicle which comprises a propulsion motor 1 and, according to the present example, three power modules 2A, 2B, 2C allowing the power supply to the motor 1. According to this embodiment , the modules 2A, 2B, 2C are identical and their constituent elements will be designated by the same numbers in the figures.

Although only three modules 2A, 2B, 2C are shown in FIG. 1, the motor 1 can be supplied by a power pack comprising any number of these modules.

The power supply modules 2A, 2B, 2C each comprise an electric accumulator 3 constituted, in the present example by lithium-ion batteries. The set of batteries 3 of all the modules 2A, 2B, 2C constitutes the capacity for storing electrical energy allowing the electric vehicle to move independently.

The electric vehicle comprises a first single-phase charging terminal 5 and a second three-phase charging terminal 6. These charging terminals 5, 6 allow charging of the battery 3 of each module 2A, 2B, 2C and may each consist of an electrical plug allowing the connection of the electric vehicle to the domestic single-phase network or to a more powerful three-phase network.

The electric vehicle comprises a supply bus 4 to which each module 2A, 2B, 2C is connected, directly or indirectly, and to which the first 5 and second 6 connection terminals are connected via a load switch 7. The switch charge 7 can be automatic or manual and allows you to select which, from the single-phase 5 or three-phase 6 plug, will be used for charging the batteries 3 according to the networks available to the user at the place where the vehicle is located.

In the present example, the motor 1 is a conventional three-phase motor. The supply bus 4 is therefore suitable for this motor 1 and comprises, in this example, three conductors adapted to deliver to the motor 1 a three-phase alternating supply whose current, voltage, and / or frequency will be controlled as a function of driving the vehicle. As a variant, the motor 1 can be of any technology requiring an alternating supply, and can comprise any number of poles, and the number of conductors of the supply bus 4 will then be adapted to the number of conductors necessary for the supply motor 1.

The modules 2A, 2B, 2C each comprise a terminal block 8 for supplying the motor 1. All of the modules 2A, 2B, 2C jointly supply the electric supply to the motor 1 by their terminal block 8 for supplying the motor. Each terminal block 8 for supplying the motor 1 has three output connections 20, 21, 22, one for each conductor of the supply bus 4. These output connections 20, 21, 22 are connected to the conductors of the supply bus 4 via a capacitor filter stage 9 (provided to ensure electromagnetic compatibility) and a relay 10 comprising a relay contact for each output connection 20, 21, 22, the relay 10 being thus adapted to connect or disconnect the output connections to the power bus 4.

Internally, the terminal block 8 for supplying a module 2A, 2B, 2C is connected to a bridge 13 of switches. Each output connection of the power supply terminal block 8 is connected to an arm 14A, 14B, 14C of the bridge 13 of switches, each arm 14A, 14B, 14C comprising two switches. The switches of bridge 13 are for example power transistors such as metal oxide gate transistors (“MOS”).

All the switches of a bridge 13 of switches are controlled by a control device made up, in the present example, of a microcontroller 15 associated with a gate control circuit 16 ("driver spoiler").

In each module 2A, 2B, 2C, a coil 17 is disposed between each arm 14A, 14B, 14C of the bridge 13 of switches and the corresponding output connection of the power supply terminal block 8. Each terminal 8 output connection therefore relates to an arm 14A, 14B, 14C of the bridge 13 and its coil 17. More precisely, each coil 17 is connected to the midpoint of an arm of the bridge 13 of switches.

The number of arms of a bridge 14 of switches is equal to: the number of poles of the motor 1; the number of conductors of the power bus 4; and the number of coils 17.

The modules 2A, 2B, 2C of this example additionally include a conventional filtering capacity 25 placed in parallel with the battery 3.

The motor 1 is in turn connected to the supply bus 4 by means of a relay 12 comprising contacts making it possible to connect or disconnect each supply conductor of the motor to a respective conductor of the supply bus 4.

The control of relays 10 and 12 makes it possible to obtain all the possible combinations of connection, via the supply bus 4, of the modules 2A, 2B, 20, of the motor 1, and of the charging terminals 5, 6. The combinations used here are the following:

- opening of relay 12 and closing of all relays 10: all modules 2A, 2B, 20 are connected to a charging terminal 5, 6 (joint charging phase of all modules);

- opening of the relay 12 and closing of the relay 10 of at least one module, while the relay 10 of at least one other module is kept open: only certain modules 2A, 2B, 2C are connected to a charging terminal 5, 6 (charging phase but only connected modules);

-closure of the relay 12 and closure of the relay 10 of at least one module, while the relay 10 of at least one other module is kept open (the charging terminals 5, 6 being disconnected from the electrical network): only certain modules 2A, 2B, 2C are connected to engine 1 (driving phase with only the connected modules which supply engine 1);

-closure of the relay 12 and closure of all the relays 10: all the modules 2A, 2B, 2C are connected to the motor 1 (running phase with all the modules which supply the motor 1).

The coils 17 of the modules 2A, 2B, 2C and the filtering stages 9 allow the modules 2A, 2B, 2C to deliver to the motor, for the supply of the latter, a smoothed voltage suitable for the windings of the motors, conventionally it is acts of a smoothed sinusoidal tension. The control of the switches of the bridge 13 is therefore carried out with a view to providing such a smoothed sinusoidal voltage whose amplitude and frequency correspond to what must be supplied to the motor 1 in order to meet the driver's demand.

The modules 2A, 2B, 2C further comprise a synchronization output 11 connected to the control circuit of the switches of the bridge 13, and more precisely here connected to the microcontroller 15. The synchronization outputs 11 of all the modules 2A, 2B, 2C are connected to a synchronization bus 18. This synchronization can be physically carried out by means of an external synchronization module (not shown) and also connected to the synchronization bus 18. Each module 2A, 2B, 2C then comprises a close control constituted by the microcontroller 15 and the gate control circuit 16, while the system as a whole comprises a control one level above (the external synchronization module) dedicated to the synchronization of the modules to supply voltages or supply or absorb currents of the same frequency and the same phase.

As a variant, in the example illustrated, the synchronization of the switching operations of the bridges 13 is carried out by providing a master-slave architecture for the modules 2A, 2B, 2C in which one of the modules is declared "master", so that the other modules, declared as “slaves”, synchronize on this master module from information that the latter makes available on the synchronization bus.

The modular architecture which has just been described operates in the manner indicated below.

Each power supply module 2A, 2B, 2C comprises a housing 23 (shown in dashed lines in FIG. 1) provided with a set of external connections. These external connections include in particular the terminal block 8 for supplying the motor 1 and comprise the synchronization output 11. Each module is a sub-assembly physically separable from the rest of the architecture. A device, for example of the “rack” type, can be provided to facilitate the insertion and removal of the power supply modules 2, by receiving and mechanically holding the module 2A, 2B, 2C and by presenting clean male-female connections. to the connections of its terminal block 8 and its synchronization output 11.

An electric vehicle thus equipped can receive, connected to the power bus 4 and to the synchronization bus. 18, a set of power modules 2A, 2B, 2C, the number of which is adapted to the traction power of the engine 1 and to the range sought for the vehicle. The modules 2, even if they meet the functional description described above, are not necessarily identical. They may in particular have different battery capacities 3 or different powers supplied. The modular architecture provides battery-converter packs allowing the coupling of heterogeneous batteries in voltage, technologies, capacities, etc. The power supply modules 2, in the form of a box 23, like elementary bricks, can be assembled according to criteria as varied as the energy requirement of the vehicle, the modules available, or the cost of the assembly. The set can evolve over time by adding, removing, or replacing power modules over time.

When an electric vehicle fitted with power supply modules 2A, 2B, 2C is in battery charging configuration, the relays 10 of the modules to be charged are closed, the relay 12 of the motor is open, and one of the charging terminals 5, 6 is connected to the electrical network. The voltage of the electrical network is then available for each module 2A, 2B, 2C on the supply bus 4. Each of the modules 2A, 2B, 2C can therefore, independently, drive its bridge 13 as a rectifier to absorb a classically sinusoidal current for recharge its battery 3. The absorption of a sinusoidal current from the energy source is conventionally necessary to respect the normative constraints on network harmonics.

As the operation in the charging phase is increasing, it is necessary that the battery voltage is, at all times, higher than the voltage supplied by the network. This constraint can be respected by sizing with an authorized voltage range for the battery which is always greater than the peak value of the network voltage throughout its range of variation.

In the charging phase, the motor 1 is not connected to the energy source since the relay 12 is open. The parasitic capacities of the motor then do not give rise to a leakage current passing through the differential circuit breaker of the installation. In the charging phase (i.e. again connector in battery charge position and not motor operation, but without provided that the battery is charged), the modules can also supply active or reactive energy to the network for part of the duration of the charging phase, if such network support functions are desired.

In addition to the simultaneous charging of all modules, various other charging strategies can be implemented using the synchronization bus. For example :

- the modules can be loaded sequentially, possibly in a specific order, which makes it possible to adapt to the available charging power or to guarantee that the differential switch does not trip when the vehicle is connected to a household electrical network. The sequential operation of the load of the modules makes it possible to apply between the phases and the ground only the capacitors of a module and not the capacitors of all the modules. The current on the earth wiring which can cause the installation's circuit breaker to trip is reduced accordingly;

- a specific module is loaded to the maximum and only then all the other modules are loaded simultaneously;

- only certain modules are loaded and others not;

- some modules are partially loaded, for example at 50% of their capacity, while other modules are loaded to the maximum.

Furthermore, when an electric vehicle fitted with power supply modules 2A, 2B, 2C is in the running configuration, the relays 10 of the modules to be charged are closed, the relay 12 of the motor is also closed, and the charging terminals 5 , 6 are disconnected from the electricity network. The modules 2A, 2B, 20 will therefore supply electrically, via the power supply bus 4, the motor 1 for the propulsion of the electric vehicle.

As previously, different power supply strategies for the engine 1 can be provided. For example :

- all the modules simultaneously supply the motor;

- only certain modules supply the motor jointly;

- the modules supply the motor one by one, sequentially (possibly in a determined order), so that when a module is unloaded, the next module takes over;

- all modules whose load is above a predetermined threshold (for example 10% of their capacity) supply the motor, and when a module passes below this threshold, it no longer supplies the motor (sound relay 10 can then be opened);

- some modules are kept as a reserve: they do not power the engine in normal times and become operational only when all the other modules are discharged;

- one of the modules (or each of the modules, sequentially) is unloaded as much as possible to readjust the indicators. Indeed, a battery management system is often associated with batteries 3, this system comprising indicators such as the state of charge of a battery or like the state of health which corresponds to the percentage between the actual capacity of the battery and its initial capacity. These indicators periodically require a complete discharge of the battery to reset their zero, that is to say to perform a tare. However, electric vehicles are rarely completely discharged and certain batteries can be charged regularly without ever being fully discharged, which leads to floating indicators and loses their initial reference over time. On the contrary, this measure makes it possible to completely discharge a module, to tare the indicators linked to the battery, while ensuring, in safety, the traction of the vehicle by the other power modules;

- the modules can cooperate so that one proceeds to intercellular balancing of its battery, thanks to the DC voltage supply of at least one other module. It is therefore no longer necessary to wait for a charging phase to carry out the intercell balancing of a module. Indeed, certain batteries may require such an intercellular balancing operation during which the battery (normally in the charging phase) balances the cells constituting it under a charging voltage.

Optionally, a module 2A, 2B, 2C can also include a battery management system for its electric accumulator. The indicators of the battery management system can be reset as indicated above.

When several modules 2A, 2B, 2C simultaneously supply the motor 1, a synchronization of the voltages supplied is provided so that the motor receives a form of voltage adapted to what it must supply for the traction of the vehicle. For example, depressing the accelerator pedal of the vehicle results in a request for torque to be supplied by the engine 1. In this case, rather than supplying, as is common in the prior art, a chopped tension whose pulse widths will be revised upwards, the system according to the invention will provide the motor with a smoothed sinusoidal voltage whose voltage, frequency and phase characteristics will be adapted to this torque demand.

FIG. 2 schematically illustrates the profiles which the voltages supplied to the motor may have. FIG. 2 comprises three curves 24A, 24B, 24C relating to the three conductors supplying the motor 1 (and therefore relating to the three conductors of the supply bus 4) . Each of these curves 24A, 24B, 24C represents the voltage supplied by two of these conductors. Each of these curves 24A, 24B, 24C has a shape close to a sinusoid. Its profile can nevertheless be crenellated but it is still close to the general shape of a sinusoid which illustrates that the control of the motor is not carried out by a chopping (such as a pulse width modulation) but is carried out by modulating the characteristics of the sinusoids such as the amplitude, the frequency and the phase shift between the sinusoids.

The shape of these sinusoids results from the superposition of the voltages provided by all of the operational modules 2A, 2B, 2C. Although these voltages are produced by switching of the bridge 13, they are smoothed by the presence of the coil 17. This presence of the coil 17 is essential because it allows the practical synchronization of the modules 2A, 2B, 2C. Indeed, if the modules were to synchronize in a timescale compatible with the switching of the bridge 13 (in other words, if the switches of the bridge 13 of different modules had to switch simultaneously), the synchronization would be difficult and expensive to achieve. According to the invention, the time scale allowed for the synchronization of the modules is much larger thanks to the coil. The production of a smoothed voltage curve allows a certain offset between the switching of the bridges 13 of the various modules, which does not prevent a resulting curve approaching a sinusoid.

Thus, whether synchronization is carried out from an external synchronization module or from the power supply module declared master (in a master-slave architecture), this module can make available information on the synchronization bus 18 than a synchronization signal, as well as the amplitude and frequency of the voltage to be supplied. This various information can for example be provided by a digital CAN type network. All the other power supply modules then switch their respective bridge 13 to achieve this same result, without precisely synchronizing the switching operations of each switch. Alternatively, the master module (or an external synchronization module) can also make available on the synchronization bus 18 a voltage shape setpoint to be obtained and, similarly, the other power supply modules supply this waveform as a result, without predicting the switching required to obtain this result. Heterogeneous power supply modules for switching electronics can thus be used together in the same vehicle.

In a particularly advantageous embodiment, the switches of the bridges 13 are made by metal-oxide silicon carbide grid power transistors (“MOS SiC”) which are large gap semiconductors, ie broadband prohibited. These transistors switch faster than conventional power transistors such as MOSFETs and thus make it possible to produce, by the power supply modules, voltages at higher frequencies which allows the use of coils 17 of lower value.

In the present example, the coils 17 can have an inductance value of 10 to 100 μΗ.

In the prior art, increasing the switching frequencies to levels permitted by the MOS SiC power transistors induces difficulties linked to electromagnetic compatibility when the motor is supplied by a chopped voltage at such frequencies. According to the invention, the high switching frequencies do not generate difficulties in this respect since each module only supplies a sinusoidal voltage which does not cause problems of electromagnetic compatibility. The electromagnetic compatibility is to be treated only within each power supply module, within a limited perimeter with the parasitic capacities subjected to the reduced switching fronts, thanks to the filtering stage 9, which can moreover be integrated into the power module.

FIG. 3 illustrates an alternative form to the embodiment of FIG. 1: the motor relay is replaced by a switch 37 comprising three-way contacts allowing the synchronization bus 4 to be connected either to the load switch 7 or to the motor 1. This alternative form allows the same functions as those described for figure 1.

FIG. 4 illustrates a variant for the power supply modules of the example in FIG. 1. According to this variant, all of the modules, or some of them, can integrate the filtering stage into their housing 23 9 and / or the relay 10. The power supply modules 2A, 2B, 2C then integrate these additional functions and the terminal block 8 is therefore located after the relay 10. The architecture on the side of the electric vehicle is thus simplified.

Figures 5 and 6 illustrate embodiments of the filtering stage 9 for a power supply module 2A, 2B, 2C.

In Figure 5, only the bridge 13 and the coils 17 of a power module have been shown to simplify the figure. The filtering stage 9 is here produced by three capacitors 26 each placed between two coils 17, as well as by three capacitors 27 each disposed between a coil 17 and the ground.

FIG. 6 represents an additional filtering stage which can be placed in series with the filtering stage of FIG. 5. This filtering stage provides common mode and differential mode filtering by means of three coils 28 associated with three capacitors 29 mounted in a star and a capacitor 39 connecting the midpoint of the star to ground.

With reference to FIGS. 7 and 8, all of the modules, or some of them, can be fitted with a heat transfer device between the electric accumulator and the switch bridge.

FIG. 7 illustrates a power supply module 2A identical to those of the example in FIG. 1, provided with such a heat transfer device. The module 2A is preferably isolated from the outside by a thermal insulator 30 associated with the housing 23. The housing 23 forms a sealed enclosure containing all the elements of the module 2A. The internal volume delimited by this sealed enclosure is filled with a heat transfer dielectric fluid 34. Cable gland type devices are provided to allow the electrical outputs, in particular the terminal block 8 and the synchronization output 11. The battery 3, the switches of the bridge 13 of switches, and the coils 17 are therefore immersed in the dielectric fluid 34, which allows a heat exchange between the battery 3 and the other components of the module 2A. In this example, the circulation of the dielectric fluid 34 is passive and takes place by convection. As a variant, a mechanical device can be used to create a circulation of the fluid in the housing 23.

FIG. 8 illustrates a second embodiment of the heat transfer device. The illustration uses certain elements from the example in Figure 7, with the same numbering. According to this second embodiment, the battery 3 is disposed in a first sealed enclosure 31 and the bridge 13 of switches is disposed in a second sealed enclosure 32. The enclosure 31 includes a thermal insulator 30 to maintain the battery in temperature. Optionally, the enclosure 32 and / or the housing 23 also include a thermal insulator 30. The sealed enclosures 31, 32 communicate by a first channel 33 and a second channel 35. The volume delimited by the sealed enclosures 31, 32 and the channels 33, 35 is filled with a heat transfer dielectric fluid 34. A pump 36 is disposed in the first channel 33 to circulate the dielectric fluid 34 between the enclosure 31 and the enclosure 32. The passage of the electrical conductors is ensured by cable gland type devices provided here on the box 23 and the speakers 31, 32. The battery 3 and the switches of the bridge 13 of switches are therefore bathed in the dielectric fluid 34, which allows a heat exchange between the battery 3 and deck 13.

In the two embodiments relating to FIGS. 7 and 8, the battery 3 is in thermal contact with components subjected to significant thermal losses (power transistors and / or coils).

In the case where the switches of the bridge 13 are made by power transistors with a metal-silicon carbide oxide grid, as described above, the coils 17 can be of reduced size and will therefore be more easily integrated, with their possible magnetic core. for example based on ferrite or amorphous materials, in the enclosure containing the heat transfer fluid 34 as in the embodiment of Figure 7, to be completely submerged there.

The thermal insulators 30 are used to minimize heat exchanges with the outside and to obtain a thermal time constant which makes it possible to maintain the accumulators at optimal temperatures thanks to the losses released by the power electronics during the driving and charging phases.

The battery can be charged without ventilation (and therefore without the associated noise), the heat given off is simply stored in the form of sensible heat by raising the temperature of the electric accumulator 3. It is only if the temperature of the electric accumulator 3 becomes too high that an external cooling will be necessary.

In the case of modules according to FIG. 4, the filtering stage 9 and the relay 10 of the module are advantageously also bathed in the dielectric fluid 34.

Preferably, the dielectric fluid 34 is a substitute for ester-based dielectric mineral oil. This type of product combines very good dielectric strength with high biodegradability and is hardly flammable.

The immersion of the battery 3, especially when it is of the lithium-ion type, in the dielectric fluid 34 increases safety due to the improved thermal transfer which limits the rise in temperature and can prevent reaching a critical threshold. in temperature causing the runaway of the accumulator.

Optionally, the supply module can comprise an external hydraulic connection comprising for example an inlet 38A and an outlet 38B (shown in FIG. 8) allowing circulation of the dielectric fluid with the outside of the module 2A. For vehicles, and more particularly for flying vehicles, which require rapid recharging while retaining the temperature conditioning of the battery, the power supply modules do not require cooling of the battery during taxi or flight. Consequently, according to one embodiment, the power supply modules 2A, 2B, 2C are not cooled during the supply of the motor 1. The rapid charge is then carried out with powerful cooling of the battery and the inverter by circulation of the dielectric fluid 34 external to the vehicle or to the aircraft, the fluid being cooled, by virtue of the hydraulic connection 38A, 38B, for example by an external exchanger (not shown), by the charging station, or by being replaced by another amount of fluid at a selected temperature. The charging terminals 5, 6 can then ensure, in addition to the electrical contacts, the hydraulic connections for the circulation of the fluid. In this case, the dielectric fluid can also be used to cool the electric cables and the associated connections. In a power pack comprising modules 2A, 2B, 2C and the charging terminals 5, 6, the external hydraulic connection 38A, 38B can thus be associated with the charging terminals 5, 6, and the dielectric fluid 34 then also bathes the load terminals 5, 6. In this case, the user connects a single plug to the load station, this plug comprising the load terminals 5, 6 as well as the input 38A and the output 38B of the external hydraulic connection.

Optionally, the thermal transfer device can include a thermal transfer stop system which can be used when the temperature of the battery is already close to the upper limit of its optimal temperature range and therefore it is not advisable to heat it. This thermal transfer stop system can consist, for example, of a valve arranged on one of the channels 33, 35 possibly associated with a bypass pipe (not shown).

The external hydraulic connection 38A, 38B also makes it possible to circulate the same dielectric fluid 34 in several supply modules 2A, 2B, 2C, so as to pool the dielectric fluid 34 for several modules.

In the context of the invention, it is chosen to use the losses of the bridges 13 of switches to heat or maintain the temperature of the electric accumulators in cold weather, and to use the heat capacity of the electric accumulators as thermal storage of the losses of the switches 13 bridges. The cooling of the bridges 13 and of the electrical accumulators 3 is shared. The thermal inertia of the battery 3 is used to store the calories corresponding to the losses of the power electronics.

According to one embodiment, the strategy for powering the motor can be provided, thanks to the synchronization bus, so that one of the modules 2A, 2B, 2C is used to, not supply the motor 1 like the other modules, but to dissipate reactive power in order to heat the dielectric fluid 34. This makes it possible to economically increase the temperature of the battery 3 when the ambient temperature is low (in winter).

The power modules 2A, 2B, 2C can also have a second life after a first life in an electric vehicle. When, for example, an electric vehicle is destroyed or when power modules 2A, 2B, 2C are no longer efficient enough for this vehicle (by aging of the battery 3), the power modules 2A, 2B, 2C concerned can then be reused in other vehicles or, for example for stationary applications, less demanding. The power supply modules 2A, 2B, 2C can, during this second life, be assembled according to a modular architecture, each brick of which has its own energy accumulator and its converter (the bridge 13) with its control electronics. allowing to function as an inverter delivering an alternating voltage.

Other alternative embodiments of the can be implemented without departing from the scope of the invention. For example, the motor 1 can be a set of several motors. The architecture can include several motors, each powered by several modules using relays.

Claims (16)

1. Power supply module (2A, 2B, 2C) for an electric vehicle engine (1), characterized in that it comprises: - an electric accumulator (3); - a bridge (13) of switches connected to the electric accumulator (3); - a housing (23) containing the elements of the power supply module; - a thermal transfer device between the electric accumulator (3) and the bridge (13) of switches, this thermal transfer device being disposed in the housing (23). 2. Power module according to claim 1, characterized in that the heat transfer device comprises at least one sealed enclosure (23, 31, 32) in which is contained a dielectric fluid (34) which bathes the electric accumulator ( 3) and the bridge (13) of switches. 3. Power module according to claim 2, characterized in that it comprises a set of coils (17) connected to the bridge (13) of switches, these coils (17) also being immersed in the dielectric fluid (34). 4. Power module according to claim 2 or 3, characterized in that the housing (23) forms said sealed enclosure. 5. Power module according to claim 2 or 3, characterized in that said sealed enclosure comprises a sealed enclosure (31) disposed around the electric accumulator (3). 6. Power module according to claim 5, characterized in that said sealed enclosure comprises a sealed enclosure (32) disposed around the bridge (13) of switches and communicating with the sealed enclosure (31) disposed around the accumulator electric (3). 7. Supply module according to claim 6, characterized in that it comprises a device (36) for the circulation of the dielectric fluid (34). 8. Power module according to any one of claims 5 to 7, characterized in that the sealed enclosure (31) disposed around the electric accumulator (3) comprises a thermal insulator (30). 9. Power supply module according to any one of the preceding claims, characterized in that it comprises a system for stopping the heat transfer. 10. Power supply module according to any one of the preceding claims, characterized in that the bridge (13) of switches is reversible, being adapted to control both the charge and the discharge of the electric accumulator (3). 11. Power module according to any one of the preceding claims, characterized in that it comprises an external hydraulic connection (38A, 38B) allowing heat exchange with other elements of the vehicle. 12. Power module according to claim 11, characterized in that the external hydraulic connection (38A, 38B) is connected to a cooling device. 13. Power pack for electric vehicle, characterized in that it comprises a plurality of modules (2A, 2B, 2C) according to one of claims 11 and 12 and in that the dielectric fluid (34) flows from one module to another by the external hydraulic connection (38A, 38B) of each module. 14. Power pack according to claim 13, characterized in that one of the modules (2A, 2B, 2C) is adapted to heat the fluid. 15. Power pack according to one of claims 12 to 14, characterized in that the power modules (2A, 2B, 2C) are not cooled during the power supply to the motor (1). 16. Power pack according to one of claims 12 to 15, characterized in that it comprises at least one charging terminal (5, 6) making it possible to connect the pack to an electrical network, the external hydraulic connection (38A , 38B) being associated with the charging terminal (5, 6), and in that the dielectric fluid (34) also bathes the charging terminal (5, 6).