Charging the battery of an electrified motor vehicle

Abstract

A method for managing electrical energy within a motor vehicle connected to an external electrical source, comprising establishing a coupling, with the external electrical source, of a vehicle electrical network to which a vehicle traction battery and a vehicle electrical power-consuming assembly are coupled, the method further comprising implementing an energy management mode from among at least a first mode (M1) in which the traction battery receives available electrical power from the external electrical source, a second mode (M2) in which the battery's state of charge is preserved for later use, and a third mode (M3) in which the traction battery compensates for any potential insufficiency in the coupling with the external electrical source to meet the needs of the power-consuming assembly. FIGURE 3

Description

Title of the invention: Charging the battery of an electrified motor vehicle

[0001] The invention falls within the field of battery charging of an electrified motor vehicle equipped with a charging function via the external electrical network.

[0002] Thus, we are interested in purely electric vehicles, equipped with one or more electric motors and a traction battery powering this or these electric motors, as well as plug-in hybrid vehicles equipped with both an internal combustion engine and an electric motor, the latter being powered by a traction battery capable of providing the vehicle with a significant range in purely electric mode, on the order of 10 to 60 km, for example. Among these plug-in hybrid vehicles, we are interested, within the scope of the present invention, both in those whose internal combustion engine is coupled or can be coupled to an axle for traction, and in vehicles in which the internal combustion engine is used to recharge the battery during a journey by means of a range-extending mechanism.In all these vehicles, the traction battery provides a voltage that is often greater than 100V, often in the range of 200 to 400V, and the motor, or each electric traction motor, is powered at this voltage.

[0003] On these electric or plug-in hybrid vehicles, the traction battery, which is often a lithium battery equipped with a Battery Management System (BMS), can be recharged while the vehicle is stationary via a wired connection through which the vehicle's electrical system is coupled to a power source, generally the electrical grid of an energy provider in a given geographical area. Recharging can also be carried out, again while stationary and using the same principles, wirelessly via an induction system that allows power to be transferred magnetically from a charging point connected to the power source to the vehicle's internal electrical system.

[0004] In this context, the invention relates to the field of control of the BMS "Battery Management System", in connection with the function of exchange with the electrical network external to the vehicle.

[0005] Independently of the function of exchanging with the external electrical network, the Battery Management System (BMS) may, depending on the circumstances, have to take into account the needs of electrical consumers of the vehicle such as the air conditioning compressor or even the vehicle's on-board heat pump (reversible air conditioning) used, for example, for pre-conditioning the vehicle's passenger compartment, the traction battery temperature management system in extreme climates (very cold or very hot outside temperature, requiring heating or cooling), or the charging or maintenance of charge of a service battery, such as a conventional 12V lead-acid battery used to power many known vehicle equipment such as the radio, interior lighting, headlights or windshield wiper motors.

[0006] It is known to control the charging of the traction battery via the external electrical grid without taking into account the other tasks typically assigned to the Battery Management System (BMS). Thus, there is no centralized management of the available energy when the traction battery is being charged using the external electrical grid.

[0007] It is noted that in certain cases, the power available to the motor vehicle from the external electrical grid can be relatively low, particularly when charging from a domestic socket. It is also noted that in some cases, it would be advantageous for the motor vehicle, and more specifically its traction battery, to be able to supply power to the external electrical grid in the event of very high demand. This strategy would help mitigate extreme demands on local power plants, for example, during winter in countries with temperate to cold climates, or during summer in countries with hot to very hot climates.

[0008] A method is known from US patent 2011 / 0282513_A1 whereby the charging of the traction battery or its discharge to the ground power grid is performed according to a signal defined by the vehicle user. Here again, the traction battery charging function is not modulated by information relating to other functions consuming electrical power in a motor vehicle equipped with a traction battery.

[0009] In this context, a method for managing electrical energy transfers within a motor vehicle connected to an external electrical source is proposed, comprising establishing a state of coupling, with the external electrical source, of an electrical network of the vehicle to which is coupled a traction battery of the vehicle and an assembly consuming electrical power of the vehicle.

[0010] The method further includes an implementation of an energy management mode among at least a first mode in which the traction battery receives available electrical power from the external electrical source and via coupling, a second mode in which the state of charge of the battery is preserved for later use, and a third mode in which the traction battery compensates for any insufficiency of the coupling with the external electrical source to cover the needs of the consumer assembly.

[0011] Advantageously and optionally,

[0012] the external electrical source may be a terrestrial electrical network equipped with a means of energy supervision external to the vehicle, and a fourth mode in which the traction battery can supply electrical power to the external electrical network by said coupling is then also available for said implementation; the implementation can be carried out in response to at least one need expressed by a vehicle user or by a vehicle supervisor; The implementation can be carried out in response to a need for thermal preconditioning of the passenger compartment of the motor vehicle, a need for recharging the traction battery, or a need for cooling or heating the traction battery; the implementation of a coupling can be carried out by implementing an AC to DC electrical converter on board the motor vehicle; The implementation of a coupling can be achieved by implementing a charging socket on the motor vehicle, a wired connection and a charging station connected to the external power source; the process may include an exit from the coupling state by switching to a state in which an electric traction motor of the vehicle is not electrically powered by the traction battery and the vehicle's electrical network is no longer coupled to the external electrical source, followed in a second step by a transition to a state in which the electric traction motor is electrically powered by the traction battery; The second mode could be the default management mode.

[0013] A system for managing electrical energy transfers within a motor vehicle connected to an external electrical source is also proposed, implementing a management process, any transition between any two of said modes being permitted without the need to go through a third of said modes.

[0014] Also proposed is a motor vehicle comprising an electrical energy transfer management system, the vehicle being an electric motor vehicle with a traction battery rechargeable when stationary by an external source or a hybrid electric and thermal motor vehicle with a battery rechargeable when stationary by an external source.

[0015] The invention will be better understood, and other objects, features, details and advantages thereof will become more apparent in the following explanatory description made with reference to the accompanying drawings given solely by way of example illustrating embodiments of the invention and in which:

[0016] [Fig.1] Fig.1 presents an electrical architecture of a vehicle according to the invention.

[0017] [Fig.2] Fig.2 shows the different states of the vehicle and the transitions between these.

[0018] [Fig.3] Fig.3 presents the different modes of energy management according to a method of embodiment of the invention.

[0019] [Fig.4] Fig.4 presents different modes of energy management according to a second embodiment of the invention.

[0020] In [Fig.1], the architecture of the motor vehicle 10 connected to a power supply equipment for electric vehicle charging 25 of the fixed charging station type is shown, itself connected to the terrestrial electrical network RET, and supplied with alternating electrical power by it.

[0021] The motor vehicle 10 includes an electric charger 11, typically an alternating current to direct current converter, or only a connector for direct current charging (different vehicles have both types of chargers, used alternately depending on the charging station used, which can supply alternating current or direct current), a traction battery 12, typically a lithium battery, or even a nickel battery, equipped with a battery management system (BMS "Battery Management System"), electrical energy consumers 13, 14, 15, etc. (forming a consumer set) including, for example, the air conditioning compressor, and at least one particular consumer which is an MT traction electric motor, not powered during charging.

[0022] In absolute terms, given such a scheme, the power available to recharge the traction battery 12 is equal to the power supplied through the charger 11 by the power supply equipment 25 (the charger 11 and the equipment 25 constituting a coupling of the vehicle network 10 to the terrestrial electrical network RET) from which are subtracted all the powers consumed by the various consumers 13, 14, 15, etc.

[0023] In the event that this difference is negative, the result is not a power available to recharge the traction battery but a power required from the traction battery to supply the electrical consumers 13, 14, 15, etc. despite the supply of energy through the charger 11 connected to the supply equipment 25 (the coupling).

[0024] It is further specified that according to safety conventions, from the moment the charger 11 is in operation, or simply the motor vehicle 10 is connected to the supply equipment 15, the traction motor MT is switched off.

[0025] In [Fig.2], the different states of the motor vehicle 10 have been represented.

[0026] A first state El “inactive” is the vehicle off state, in which the electric motor of the motor vehicle is off, and the vehicle charger 11 is also off, not supplying any power to the on-board electrical network.

[0027] A second state E2, "plug-in," is a state in which the electric motor MT is also off, the vehicle is stationary, but in which the electric charger 11 is operating, transmitting energy from the terrestrial electrical grid RET to the vehicle's on-board electrical grid 10, or vice versa. A wired connection has been established, or alternatively, a fixed inductive contactless charging device is used, with the vehicle stationary.

[0028] The transition between the "inactive" state El and the "connected" state E2 can take place in either direction.

[0029] A third state E3 “movement” corresponds to the situation in which the electric traction motor MT operates, so as to move the motor vehicle 10 forward or at least transmit power to the drive wheel(s).

[0030] In this state E3, the electric charger 11 is not operational, and there is no transfer of electrical power between the terrestrial territory electrical network RET and the on-board electrical network of the motor vehicle 10. In particular, any wired connection is eliminated.

[0031] The transition between the first state El “inactive” and the third state E3 “movement” can take place in either direction.

[0032] Conversely, the transition between the second state E2 “connected” and the third state E3 “movement” only occurs in the direction from E3 “movement” to E2 “connected”. Indeed, it is not intended to go directly from the second state E2 “connected”, corresponding in particular to charging, to the third state E3 “movement”, corresponding in particular to a road journey, without passing through the first state E1 “inactive”, in which the vehicle is switched off, for reasons of ergonomics and safety.

[0033] In [Fig.3], the four energy management modes of the motor vehicle 10 connected to the electricity supply equipment 15, in state E2, according to an embodiment of the invention, are shown.

[0034] A first mode Ml is a "charge" mode, in which the recharging of the traction battery 12 is permitted, and moreover guaranteed, and in which the charge level of the traction battery 12 is necessarily increasing over time.

[0035] In this "charge" mode M1, discharging the traction battery to power consumers 13, 14, 15, etc., is not permitted, nor is discharging the traction battery to power the terrestrial electrical grid via the charger 11. Consumers 13, 14, 15 receive power from the grid. RET terrestrial electrical network. The traction battery 12 receives from the RET terrestrial electrical network the power available from it, deducting the power consumed by consumers 13, 14, 15, whose operation can, in certain variants, be modulated or not according to the priority given to the fastest possible charging of the traction battery 12.

[0036] A second mode M2 ​​is the "balance" mode. In this mode, the charge level of the traction battery 12 is necessarily constant, because charging the traction battery 12 is not permitted and discharging it is not permitted either.

[0037] Thus, consumers 13, 14, 15, etc. are not powered by the traction battery 12, and the terrestrial electrical grid RET cannot receive power from the traction battery 12. Consumers 13, 14, 15 receive power from the terrestrial electrical grid RET. The state of charge of the traction battery 12 is thus preserved for later use, preventing any use by consumers 13, 14, 15, or, in some variants, preventing any use by at least some of the consumers 13, 14, 15.

[0038] A third mode M3 is the "discharge" mode in which the charging of the traction battery 12 is not permitted but on the other hand, its discharge is permitted, for the benefit of the consumers 13, 14, 15. As a result, the level of the state of charge of the traction battery 12 can only decrease over time.

[0039] In this M3 “discharge” mode, the traction battery 12 can be used to power electrical consumers 13, 14, 15, etc. if the terrestrial electrical network RET is unable to supply them with sufficient power to meet their needs through the electric charger 11. However, the traction battery 12 cannot supplement the needs of the terrestrial electrical network RET during peak consumption periods, because the coupling (the electric charger 11 and / or the supply equipment 25) does not allow it.

[0040] A fourth M4 mode is the "free" mode.

[0041] In this mode, charging of the traction battery 12 is permitted and discharging of the traction battery 12 is also permitted. Thus, depending on the circumstances, the traction battery 12 can be used to power consumers 13, 14, 15, etc., or to supply the terrestrial electrical grid in the event of a peak consumption, but can also receive power from said terrestrial electrical grid to increase its state of charge, particularly for the purpose of driving a vehicle.

[0042] It follows in this "free" M4 mode that the monotony of the evolution of the level of the state of charge of the traction battery 12 is neither guaranteed nor sought.

[0043] External monitoring of the state of charge of the traction battery 12 is entrusted to a controller 20 ([Fig. 1]), which may belong to an external charging equipment operator or may be owned by the owner of the motor vehicle 10 and which, in any case, is external to the vehicle and not on board. This "free" M4 mode is particularly interesting in the context of smart charging within a smart grid.

[0044] It is specified that the transition from any of the Ml to M4 modes to any other of the Ml to M4 modes is in any case possible, and that in the context of the initialization of the motor vehicle 10, it is generally the M2 "balance" mode that is activated by default.

[0045] The conditions for switching from one of the M1 to M4 modes to another of the M1 to M4 modes are chosen according to the technical characteristics of the motor vehicle 10 or its configuration, defined for the end user.

[0046] The passage conditions reflect the needs expressed by the user, and by the system itself.

[0047] Thus, these conditions may take into account the user's desire to charge the traction battery 12 or the fact that the motor vehicle 10 has detected that the temperature of the traction battery 12 is insufficient for optimal use of the vehicle's traction chain and that it is necessary to use the energy of this battery to increase its temperature by means of a heater, for example a resistive heater.

[0048] The four management modes M1 to M4 aim to cover all possible life case modes for optimized vehicle energy management.

[0049] In the Ml “charge” mode, the supply of electrical energy by the charger 11 is at its maximum for the purpose of recharging the battery 12, the consumption of electrical energy by the consumers 13, 14, 15, etc. is limited in any case by the supply capacity through the charger 11 and the state of charge of the traction battery 12 is increasing.

[0050] In the M2 “balance” mode, the supply of electrical energy through the charger 11 is regulated by the electrical consumption level of the consumers 13, 14, 15, etc. The electrical energy consumption by these consumers 13, 14, 15 is limited to the maximum supply capacity through the charger 11 (which depends on the charger 11 and the supply equipment 15). The charge level of the traction battery 12 is constant for the purposes of a subsequent driving phase, but it is chosen not to consume power from the terrestrial electrical grid (RET) for battery charging, in particular to reduce the associated electricity bill.

[0051] In the M3 "discharge" management mode, the supply of electrical energy by the charger 11 is regulated by the electrical consumption of the consumers 13, 14, 15, etc., but the energy consumption of consumers 13, 14, 15, etc., is not limited by the charging equipment (charger 11 and supply equipment 25) since it can draw power from the traction battery 12, and the charge level of the traction battery 12 is either constant or decreasing over time. Thus, the operation of consumers 13, 14, and 15 is not limited (given their size, which naturally allows them to be powered by the traction battery 12). The traction battery 12 compensates for any potential inadequacy of the connection to the terrestrial electrical grid (RET) to meet the consumers' needs.

[0052] In the M4 “free” management mode, external supervision is carried out to decide whether to supply electrical energy to the motor vehicle 10 or to obtain energy from said vehicle for the benefit of the terrestrial electrical grid RET. The energy consumption by the consumers 13, 14, 15, etc. is supervised by the external supervisor or controller 20, and the state of charge level of the traction battery 12 can vary upwards or downwards depending on the circumstances.

[0053] According to an embodiment shown in [Fig. 4], the "free" M4 management mode is not present or accessible, in particular because the vehicle model in question is not intended to operate with smart grid-type usage. As a result, only the M1, M2, and M3 management modes are accessible. As before, when the vehicle management is initialized in the "connected" (typically plug-in) state E2, the M2 mode is the default mode. In the embodiment of [Fig. 4], all transitions between the three modes are possible.

[0054] The invention presented enables efficient energy management of the traction battery 12. This energy management is simplified by the use of general modes (or macro modes), in which reliable vehicle operation is guaranteed. These modes allow the supply of electrical power in the "connected" state (E2) for recharging the traction battery 12, pre-conditioning the vehicle's passenger compartment, and cooling or heating the traction battery 12 in extreme temperature conditions, whether hot or cold. Other electrical power supplies are possible in the "connected" mode, for example, to the headlights, or to any removable tool used by the user and connected to the vehicle's 12V system.

[0055] The transition between the four modes M1 to M4 constitutes the implementation of a four-state automaton corresponding to the four general modes described. In each mode, operation is guaranteed. It allows for the determination of energy supply priorities and ensures that these priorities are respected.

[0056] It is further specified that each of the macro modes corresponds to a desired behavior, without further details. The technical solution to be implemented for Achieving the desired behavior is left to the discretion of the developers. The desired behaviors correspond in particular to the wishes of the vehicle user.10

[0057] The system includes lists of conditions for switching from one Ml to M4 mode to another of the Ml to M4 modes and the definition of these switching conditions is at the discretion of the developers of the motor vehicle models 10.

[0058] These conditions reflect the needs expressed by the user of the motor vehicle 10 or by the motor vehicle 10 itself. A need expressed by the user of the motor vehicle 10 may be to recharge the traction battery 12. A need expressed by the motor vehicle 10 itself may be to heat the traction battery 12 in case of extreme cold, or to cool it in case of extreme heat.

[0059] The management modes M1 to M4 define the control of the active elements of the vehicle's electrical circuit, from the traction battery 12 to the charger 11, as well as the various electrical consumers 13, 14, 15, etc., some of which are supplied with a voltage of around 300 volts or more corresponding to the output voltage of the traction battery 12 and others are supplied with a lower voltage of around 12 V DC (extra low voltage: ELV), within the framework of a conventional electrical network which can itself be supplied by the on-board network connected directly to the traction battery 12, via a DC to DC power converter.

[0060] It is specified that a control strategy is put in place which commands and impacts all active components consuming electrical power, whether they are consumers or producers during all phases of the life of the electric vehicle 10 in which it is connected to the terrestrial electrical network, in the sense of meeting the conditions necessary for the supply of electrical power from the external energy source, which is generally constituted by the terrestrial electrical network RET.

[0061] It is specified that the M4 mode (“free”) may not be installed in the motor vehicle 10, or may also be installed without being activated, while leaving the possibility for an operator to activate it after a long period of use of the vehicle, when the conditions of use in connection with the terrestrial electrical network RET are met for an adapted use of the smart grid type to allow the territorial electrical network to be helped in terms of power supply by the traction battery 12 of the motor vehicle 10, and those of other similar vehicles.

[0062] The processes presented offer simple energy management, with a similarly simplified control module. This results in greater robustness of the module. command and control and under development of each motor vehicle model, a gain in design and validation time.

[0063] The readability of the control system over time is improved, benefiting all stakeholders, from the developer to the user. The invention offers significant flexibility to those involved in the development process of each motor vehicle model.

[0064] This results in accounting (financial) gains in the development phase of motor vehicle models.

[0065] Moreover, in another area, the invention makes it easy to develop strategies for the physical protection of the system and its components.

[0066] By way of example, we will cite the fact that if the state of charge of the traction battery 12 approaches a lower threshold value below which the traction battery 12 is likely to be damaged, it is then possible to prevent, under all circumstances, its discharge by using one of the macro modes M1 to M4 chosen for this purpose, in this case, mode M1 or mode M2, while prohibiting the transition to modes M3 and M4, while the traction battery 12 recovers a state of charge safe for its integrity, by the user of mode M1, immediately or delayed.

[0067] Thus, it is possible to make accounting gains over the life of the mass-produced motor vehicle models, since their traction battery 12 will be protected against excessive discharge and against the resulting loss of capacity.

Claims

Demands

1. A method for managing electrical energy transfers within a motor vehicle (10) connected to an external electrical source (RET), comprising establishing (E2) a coupling (11, 25) with the external electrical source (RET), of a vehicle electrical network to which is coupled a vehicle traction battery (12) and a vehicle electrical power-consuming assembly (13, 14, 15), characterized in that the method further comprises implementing an energy management mode from among at least a first mode (M1) in which the traction battery (12) receives available electrical power from the external electrical source (RET) and via the coupling (11, 25), a second mode (M2) in which the state of charge of the battery (12) is preserved for subsequent use, and a third mode (M3) in which the traction battery (12) compensates for a possible insufficiency of the coupling (11, 25).25) with the external power source (RET) to cover the needs of the entire consumer set (13, 14, 15), and in that a default management mode is the second mode (M2).

2. Method of managing electrical energy transfers according to claim 1, characterized in that the external electrical source (RET) is a terrestrial electrical network (RET) equipped with an external energy supervision means to the vehicle (20), and a fourth mode (M4) in which the traction battery (12) can supply electrical power to the external electrical network (RET) by said coupling (11, 25) is also available for said implementation.

3. Management method according to claim 1 or claim 2, characterized in that the implementation is carried out in response to at least one need issued by a vehicle user (10) or by a vehicle supervisor (10).

4. Method of managing electrical energy transfers according to any one of claims 1 to 3, characterized in that the implementation is carried out in response to a need for thermal preconditioning of the passenger compartment of the motor vehicle (10), a need for recharging the traction battery (12), or a need for cooling or heating the traction battery (12).

5. Method of managing electrical energy transfers according to any one of claims 1 to 4, characterized in that the implementation (E2) of a coupling (11, 25) is carried out by implementing an alternating current to direct current electrical converter (11) embedded in the motor vehicle (10).

6. Method of managing electrical energy transfers according to any one of claims 1 to 5, characterized in that the implementation (E2) of a coupling (11, 25) is carried out by implementing a charging socket of the motor vehicle, a wired connection and a charging station (25) connected to the external electrical source (RET).

7. Method of managing electrical energy transfers according to any one of claims 1 to 6, characterized in that it comprises a switchover to a state (E1) in which an electric traction motor (MT) of the vehicle is not electrically powered by the traction battery (12) and the vehicle's electrical network is no longer coupled to the external electrical source (RET), followed in a second step by a transition to a state (E3) in which the electric traction motor (MT) is electrically powered by the traction battery (12).

8. Electrical energy transfer management system within a motor vehicle (12) connected to an external electrical source (RET) implementing a management method according to any one of claims 1 to 7, characterized in that any transition between any two of said modes is permitted without the need to go through a third of said modes.

9. Motor vehicle (10) comprising an electrical energy transfer management system according to claim 8, characterized in that the vehicle (10) is an electric motor vehicle with a traction battery rechargeable when stationary by an external source or a hybrid electric and thermal motor vehicle with a battery rechargeable when stationary by an external source.