FR2962263A1 - Method for contact-less charging of power supply battery of motor vehicle i.e. electric car, involves detecting end of charge of battery by transmitter, and inactivating receiver at end of charge of battery - Google Patents

Abstract

The method involves detecting end of charge of a power supply battery (10) of a motor vehicle by a transmitter (12), and inactivating a receiver (2) at the end of charge of the battery, where the receiver is arranged within the vehicle. A switch (6) mounted in parallel with a coil (3) of the receiver is automatically actuated to inactivate the receiver. Presence of the battery to be charged is detected by the transmitter by measurement and analysis of a pulse train considering intensity and voltage at the level of the transmitter. Independent claims are also included for the following: (1) a control unit for a charging system of a power supply battery of a motor vehicle, comprising hardware and/or software units for implementing a power supply battery charging method (2) a transmitter of a charging system for a power supply battery of a motor vehicle (3) a receiver of a charging system for a power supply battery of a motor vehicle (4) a charging system for a power supply battery of a motor vehicle.

Description

The present invention relates to a method of charging a motor vehicle battery. It also relates to a transmitter, a receiver and a charging system comprising such a transmitter and such a receiver implementing such a method of charging a battery. It also relates to a motor vehicle as such equipped with such a receiver to implement the charging method of its battery.

Some motor vehicles have an electric traction chain, such as electric vehicles, with only an electric traction chain, or hybrid vehicles, with both a thermal and electric traction chain. These vehicles can be equipped with a battery that is recharged using a charger when it is discharged.

A first family of charging solutions of a motor vehicle battery, called "with contact", based on a direct and continuous electrical connection between the battery and the charger, the latter thus delivering an electric current to the battery through this connection that allows charging the battery. A first approach is to use the power grid: this allows the battery to be charged from low power, of the order of 3 kW, which requires a long charging time of several hours. According to a second approach, powerful chargers are used, for example offering a power of up to 100 kW. All contact battery charging solutions also have the following drawbacks: corrosion of the electrical contacts at the connection between the charger, the battery and the AC mains reduces their reliability; - The connection with contact is difficult to ensure in a humid environment; - The connection with contact requires electrical manipulation, is not very user-friendly and generally requires devices managing the hygiene of the charging cable, for example a winder.

A second family of automotive battery charging solutions, called "non-contact", relies on remote charging via a charging system, also called "charger", having a transmitting primary portion comprising in particular a primary coil, which we more simply call "transmitter", which cooperates with a receiving secondary part comprising in particular a secondary coil, which we more simply call "receiver", mounted on the motor vehicle and connected to the battery to be recharged. The primary coil thus transmits a magnetic field sufficient to induce the charging current required for charging the battery at the secondary coil.

The disadvantage of existing "non-contact" solutions is that they require communication between a vehicle and the transmitter, to avoid the transmission of load power when the vehicle is absent, or poorly. positioned, or when its battery is already charged. Existing solutions are not satisfactory to respond to these situations.

Thus, the object of the invention is to propose a charging solution for a motor vehicle battery which does not have all or some of the disadvantages of the state of the art.

More precisely, an object of the invention is to propose a simple and reliable charging solution for a motor vehicle battery which guarantees charging operation only when it is expedient. For this purpose, the invention is based on a method for charging a battery for powering a motor vehicle, from a charging system comprising on the one hand an emitter and on the other hand a receiver disposed within the motor vehicle, characterized in that it includes a final step of detecting end of charge of the battery and inactivation of the receiver at the end of charging.

The final step of inactivation of the receiver at the end of charging may include the automatic actuation of a switch mounted in parallel with the coil of the receiver. The charging method of a power supply battery of a motor vehicle may comprise a step of detection by the transmitter of the power absorbed by the receiver and below a certain predefined threshold, it may be considered that the battery is fully charged and the final step of inactivation of the receiver must be initiated.

The method of charging a battery may comprise a step of detecting the presence of a battery to be charged by the transmitter by measuring and analyzing a pulse train taking into account the intensity and the voltage at the transmitter.

The step of detecting the presence of a battery to be charged by the transmitter may include measuring and analyzing the input power of the transmitter.

The method of charging a battery may comprise a prior step of closing a switch connected in series with the receiver coil to make the receiver active and detectable by the transmitter. The method of charging a battery may comprise a preliminary step of activating the transmitter to implement the step of detecting the presence of a battery to be charged and / or a final step of inactivation of this transmitter after the end of the charge.

The invention also relates to a control means for a charging system of a battery for powering a motor vehicle, characterized in that it comprises software and / or hardware means and implements the method of charging a battery for powering a motor vehicle as described above. The invention also relates to a transmitter of a charging system for a power supply battery of a motor vehicle, characterized in that it comprises a control means which implements the charging method of a battery of power supply of a motor vehicle as described above.

The invention also relates to a receiver of a charge system for a battery for powering a motor vehicle, characterized in that it implements the charging method of a power supply battery of a motor vehicle. motor vehicle as described above. The receiver may include a switch mounted in parallel with the receiver coil, to make active and detectable or not the receiver by a transmitter. It may include a switch mounted in series with the receiver coil.

The invention also relates to a motor vehicle comprising a battery for power supply, characterized in that it comprises a receiver as described above for charging its battery.

The motor vehicle may include a switch at its dashboard to make active or not the receiver by a transmitter. The invention also relates to a charging system for a battery for powering a motor vehicle, characterized in that it comprises a receiver as previously described arranged within the motor vehicle and an emitter as described above.

These objects, features and advantages of the present invention will be set forth in detail in the following description of a particular embodiment made in a non-limiting manner in relation to the appended figures among which:

Figure 1 schematically shows a side view of a motor vehicle charging phase without contact with its battery according to the invention.

Figure 2 schematically shows a side view of a non-contact charging system according to the invention.

FIG. 3 diagrammatically represents the electric circuit of the charging system of a battery according to the invention.

Figure 4 schematically shows the electric circuit of the charging system of a battery. Figure 5 shows the electric circuit of the charging device of a battery.

Figure 6 illustrates the temporal evolution of the voltage after the rectifier and the intensity at the emitter at the beginning of the charging process. Figure 7 illustrates the time evolution of the voltage and the voltage. intensity at the receiver at the beginning of the charging process.

FIG. 8 diagrammatically represents the electric circuit of the charging system of a battery according to one embodiment of the invention.

FIG. 9 represents the electric circuit of the charging system of a battery according to the embodiment of the invention.

FIG. 10 illustrates the temporal evolution of the voltage and intensity at the transmitter at the end of the charging method according to the embodiment of the invention.

FIG. 11 illustrates the temporal evolution of the voltage and the intensity at the receiver at the end of the charging method according to the embodiment of the invention.

Without limitation, the invention will be described in connection with an electric motor vehicle.

An electric motor vehicle 1, whose motor is supplied with electrical energy by a battery, is equipped in its sill with a non-contact receiver 2 connected to the not shown battery, which receives a power 9 transmitted by a transmitter 12 to through a space 7 between the transmitter 12 and the receiver 2, while the vehicle rests on the ground 8 of a parking space equipped with a transmitter 12, as shown in Figure 1. The charging system of the Vehicle battery therefore consists of two main components that cooperate without contact, a transmitter 12 fixed to the ground 8 and a receiver 2 mounted on the motor vehicle.30 The transmitter 12 mainly comprises a so-called primary coil 13, which is positioned so fixed at a parking place of a motor vehicle, powered by a resonant circuit which will be described later. This transmitter 12 is advantageously integrated into a volume arranged within the parking space, so that the portion of the transmitter 12 comprising the primary coil 13 does not exceed or slightly above the ground level 8 on which is placed a motor vehicle . Alternatively, the transmitter can be disposed entirely above the ground 8 to facilitate its positioning.

2 schematically illustrates in side section the relative position of the coil 13 of the transmitter 12, which protrudes slightly above the ground level 8, so as to be at a distance e below the so-called coil secondary 3 of the receiver 2 arranged within the motor vehicle 1, in a vertical direction z. The secondary coil 3 is adapted to receive a power 9 transmitted by the primary coil 13 through the space 7 separating them, called gap, without requiring a physical electrical connection at the motor vehicle. The receiver 2 is advantageously arranged in the underside of the motor vehicle, integrated in the chassis of the vehicle, to minimize the distance e and optimize power transfer through the space 7. This battery charging system can be positioned at different vehicle positions, for example in the front part, in the middle or even in the rear part of the vehicle.

FIG. 3 schematically represents the electrical diagram of the non-contact charging system of a battery 10 of a motor vehicle according to the invention. The transmitter 12 comprises a connection 15 to the electrical power distribution network or sector 16, an AC / DC converter 17 whose function is to transform the AC current of the sector 16 into a direct current, supplying a DC voltage Vdc. input of an inverter 18 whose function is to transmit an oscillating power at the primary coil 13. The receiver 2, arranged within the motor vehicle, comprises a secondary coil 3 which receives the power transmitted by the primary coil 13, whose generated magnetic field induces an electric current within the secondary coil 3 through the space 7. This electric current passes through a regulator or rectifier 4 and then a filter 11 before reaching the battery 10, thus allowing its charging. The charging system is further controlled by a control device 19, which comprises software and / or hardware means for implementing a battery charging method, which will be explained later.

The concept of the invention consists in implementing a detection of the end of charge of a battery by the transmitter and the deactivation of the receiver at the end of charge so as not to emit a full power of charge towards the battery when this does not occur. is not necessary, to avoid damage to a battery by overcharging. This can be implemented or supplemented by the detection of the presence of a battery to be charged.

For this, the control device 19 of the transmitter 12 implements a step of transmitting a low power train and detects the modification of this power train to deduce the presence or absence of a battery 10 to load. A low-power train is understood to mean a pulse train whose transmitted power is between a few W and a few tens of W, for example 50 W in the case where the rated load power is 3KW.

More specifically, the charging method according to the invention implements the following steps:

El0 - periodic sending of a low power pulse train by the transmitter 12; E20 - measurement and analysis of the time evolution of the pulse train at the transmitter 12 to deduce the presence or absence of a receiver 2 for charging a battery.

Then, after detection of the presence of a battery to be charged, the control device 19 of the transmitter 12 triggers a step E30 operating at full power of the transmitter, which thus goes into an optimal operating mode to load the transmitter. drums.

Optionally, the control means can implement the following preliminary steps before operating at full power: E25: verification of the relative positioning of the receiver 2 of the motor vehicle with respect to the transmitter 12, by the measurement and analysis of the temporal evolution of the power of the pulse train or the current and the voltage at the emitter 12; E26: beyond a threshold, the positioning is considered unsatisfactory and the charging step E30 is not engaged.

The acceptable threshold of the positioning of the receiver 12 of the automobile vehicle may for example be a gap of at most 20 centimeters from the center of the coil 13 of the transmitter 12.

FIG. 4 schematically illustrates the circuit diagram of the non-contact charging system of a motor vehicle battery 10 according to one possible variant of the invention, which comprises a switch 5 connected in series with the coil 3 on the receiver 2 of the motor vehicle. According to an advantageous embodiment, this switch 5 is in the form of a button positioned at the dashboard of the motor vehicle but one could consider other man-machine interface means 30 to fulfill this function. Alternatively, this switch can be controlled by a battery charge computer present in the motor vehicle. This electrical embodiment can be combined with the embodiment of the invention which will be described later with reference to FIGS. 8 to 10.

When the switch 5 is open, the receiver 2 is not active and is therefore undetectable by the transmitter 12. Thus, the charging method implemented by this embodiment comprises a prior step E05 closing the switch 5, by the driver of the motor vehicle when he parked his vehicle and that he believes that the conditions are met for the charging of his battery. From the moment when the switch 5 is closed, the transmitter 12 will then detect the presence of the receiver 2 according to the method described above. Alternatively, the actuation of this switch can be automatic.

Figure 5 shows in more detail the circuit diagram of the non-contact battery charging system of Figure 4.

FIG. 6 illustrates, by the curves 20, the evolution as a function of time of respectively the voltage and the intensity, measured at the emitter 12. The curve 22 represents the position of the switch 5, takes the value 0 when open and 1 when closed. Thus, at time t 1, the switch 5 moves from the open to closed position. Before time ti, the transmitter is characterized by a voltage V and an intensity I, which are generated according to step El0 explained above. The presence of the coil 3 of the receiver 2 induces a modification of the temporal evolution of the voltage and the intensity within the emitter 12. Indeed, it appears that the amplitude of the current is modified, as well as the phase shift. between the voltage and the current, which also materializes by a modification of the input power of the transmitter. The combined use of current and voltage thus makes it possible to easily detect this phenomenon due to the presence of a battery charge receiver by means of the relatively simple measurement of this power.

Thus, the step of periodically sending a pulse train E10 at low power by the transmitter 12 is performed here by undulatory signals of voltage and intensity. Then, the step of measuring and analyzing the pulse train E20 comprises measuring and analyzing the input power of the transmitter. Alternatively, any other method taking into account the temporal evolution of the current and voltage at the transmitter 12 may allow to deduce the presence or absence of a receiver 2 for charging a battery.

As a remark, FIG. 7 illustrates by curves 23, 24 the evolution as a function of time of respectively the voltage and the intensity, measured at the level of receiver 2. Before time t i, nothing happens at the level of receiver. Then, we notice the appearance of a tension and an intensity.

According to another embodiment, another switch can also be implemented at the transmitter, allowing it to start or not.

Thus, when the driver has parked his motor vehicle and wishes to recharge his battery, he must not only operate the switch 5 on board his motor vehicle but also the switch of the transmitter, which can be in a device. actuation positioned at the edge of the parking space. In this variant, the charging method thus comprises another step E07 prior to activation of the transmitter. Without this activation, the detection phase of the battery to be charged is not triggered.

FIGS. 8 and 9 illustrate the wiring diagram of the non-contact charging system of a motor vehicle battery 10 according to an embodiment of the invention, which comprises a switch 6 connected in parallel with the coil 3 of the mounted receiver 2 on the motor vehicle. This switch 6 is used to manage the end of charge of the charging process. This embodiment of the invention may naturally be the subject of alternative embodiments by exploiting the embodiments explained above.

When the switch 6 is closed, the receiver 2 is no longer active and is no longer subject to the power transmitted by the transmitter 12. Thus, the charging method implemented by this embodiment comprises a final step of automatic actuation of the switch 6 to turn off the receiver and terminate the charge of the battery.

For this, the transmitter 12 detects that the transmitted power is less and less absorbed by the receiver 2 and beyond a certain predefined threshold, it is considered that the battery 10 is fully charged. In this case, the charging process is stopped by the actuation of the switch 6, which avoids overcharging the battery which could damage it.

More generally, the charging method according to the invention comprises a final step E40 for detecting the end of charge of the battery 10 and the inactivation of the receiver 2 at the end of charging.

FIG. 10 illustrates by curves 30, 31 the evolution as a function of time of respectively the voltage and the intensity, measured at the emitter 12. The curve 32 represents the position of the switch 6, takes the value 0 25 when the receiver is active and 1 when it is inactive. Thus, at time tf, the control device 19 of the transmitter 12, or any computer present on the secondary circuit, at the receiver 2, detects the end of charging the battery. It then controls the actuation of the switch 6. This induces the deactivation of the coil 3 of the receiver 2, which causes a change in the temporal evolution of the voltage and the intensity within the transmitter 12.

As a remark, FIG. 11 illustrates by curves 33, 34 the evolution as a function of time of respectively the voltage and the intensity, measured at the level of the receiver 2. Before the instant tf, the secondary circuit is subjected to a voltage which becomes zero as soon as the switch 6 is actuated at time tf. Thus, the battery 10 is protected from any overload after the instant tf.

The end-of-charge process described above also applies if the vehicle is moved during the charging phase or in case of abnormality during charging.

The previous execution mode has been described by way of non-limiting example and it is obvious that other modes of execution can be implemented, in particular by simple combination of the schemes described above. On the other hand, the invention has been illustrated from certain electrical diagrams by way of example. It is applicable to any equivalent implementation at the electrical level. For example, the reels can have any shape, circular, rectangle, square, etc. The inverter can be in various forms, with any number of transistors, for example only two, with other types of transistor, etc.

The charging method is implemented by a control device of the charging system, which comprises software and / or hardware elements (hardware and / or software). The control device comprises for example mainly one or more microprocessors. It can be arranged at the transmitter, or alternatively at the receiver, or partially on each of the two components.

The invention has been described on the basis of a battery transmitter fixed at ground level. However, the concept of the invention remains compatible and applicable to any other transmitter, for example portable, mobile, but also to a transmitter that would not be fixed at ground level but on a wall, able to cooperate with a receiver placed in correspondence on the vehicle.

Claims (14)

1. A method of charging a battery (10) for powering a motor vehicle, from a charging system comprising on the one hand a transmitter (12) and on the other hand a receiver ( 2) disposed within the motor vehicle, characterized in that it comprises a final step (E40) for detecting end of charge of the battery (10) and inactivation of the receiver (2) at the end of charging. 2. Method for charging a battery (10) for powering a motor vehicle according to the preceding claim, characterized in that the final step (E40) of inactivation of the receiver (2) at the end of charging comprises the automatic actuation of a switch (6) connected in parallel with the coil (3) of the receiver (2). 3. A method of charging a battery (10) for powering a motor vehicle according to one of the preceding claims, characterized in that it comprises a step of detection by the transmitter (12) of the power absorbed by the receiver (2) and below a certain predefined threshold, it is considered that the battery (10) is fully charged and that the final step (E40) of inactivation of the receiver (2 ). 4. Method for charging a battery (10) for powering a motor vehicle according to one of the preceding claims, characterized in that it comprises a step of detecting the presence of a battery (10). to be charged by the transmitter (12) by measuring and analyzing a pulse train taking into account the intensity and the voltage at the transmitter (12). 5. Method for charging a battery (10) for powering a motor vehicle according to the preceding claim, characterized in that the step of detecting the presence of a battery (10) to be charged by the transmitter (12) includes measuring and analyzing the input power of the transmitter (12). 6. A method of charging a battery (10) for powering a motor vehicle according to one of the preceding claims, characterized in that it comprises a preliminary step (E05) of closing a switch (5). ) connected in series with the coil (3) of the receiver (2) to make the receiver (2) active and detectable by the transmitter (12). 7. A method of charging a battery (10) for powering a motor vehicle according to one of the preceding claims, characterized in that it comprises a prior step (E07) of activation of the transmitter ( 12) for it to implement the step of detecting the presence of a battery (10) to be charged and / or a final step of inactivation of this transmitter (12) after the end of the charge. 8. Control means (19) for a charging system of a battery (10) for powering a motor vehicle, characterized in that it comprises software and / or hardware means which implement the method for charging a battery (10) for powering a motor vehicle according to one of the preceding claims. 9. Transmitter (12) of a charging system for a battery (10) for powering a motor vehicle, characterized in that it comprises a control means (19) which implements the charging method of a battery (10) for powering a motor vehicle according to one of claims 1 to 7. 10. Receiver (2) of a charge system for battery (10) for powering a motor vehicle, characterized in that it comprises a switch (5) connected in parallel with the coil (3) of the receiver (2), to make the receiver (2) active and detectable or not by an emitter (12). Receiver (2) for a charging system for a battery (10) for powering a motor vehicle according to the preceding claim, characterized in that it comprises a switch (5) connected in series with the coil ( 3) of the receiver (2). 12. Motor vehicle comprising a battery (10) power supply, characterized in that it comprises a receiver (2) according to one of claims 10 or 11 for charging its battery (10). 10 13. Motor vehicle according to the preceding claim, characterized in that it comprises a switch at its dashboard to make active or not the receiver (2) by a transmitter (12). 14. Charging system for a battery (10) for powering a motor vehicle, characterized in that it comprises a receiver (2), one of the claims 10 or 11 disposed within the motor vehicle, and a transmitter according to claim 9. 20