Electric vehicle auxiliary battery charger and electric vehicle including such a charger

Abstract

The present invention relates to a charger (1; 10) for an electric vehicle auxiliary battery, said charger comprising: – a power supply (3); – an electrical connection (5) configured to connect to the vehicle's auxiliary electrical network and to connect said power supply (3) to the vehicle battery; – an electrical management circuit (7; 27) configured to limit the intensity of the electrical current (IOUT) flowing, via the auxiliary electrical network, from the power supply (3) to the vehicle battery. Figure for the abstract: Fig 1

Description

Title of the invention: Electric vehicle service battery charger and electric vehicle comprising such a charger

[0001] The present invention relates to the field of devices for electrically charging a battery, and more particularly a service battery mounted in an electric and / or hydrogen vehicle (also designated respectively by the acronyms PEV and H2EV).

[0002] A service battery is understood to mean a battery supplying electricity in particular to the functional and / or safety components of the vehicle, such as the computer, the door locking system, the OBD (On-Board Diagnostics) link, the autonomous driving aids, the LED headlights, the parking brake, the radio, the geolocation system, the electric traction management, etc. The electrical network supplied by said service battery is thus generally called a “service electrical network”.

[0003] Service batteries for electric vehicles are generally lower capacity batteries than traction batteries, and have a nominal voltage of 12 volts. These are so-called "deep cycle" batteries, or also called "slow discharge batteries", because they do not withstand high current draws very well (not designed to start a thermal engine), but they do withstand deep discharges very well, up to 80% of their capacity. These batteries are generally located in the electric traction compartment (surrounded by safety protections) and are barely or not accessible. In addition, to protect these batteries against destructive interventions, the use of cables to connect them to another vehicle is prohibited in most electric vehicle user manuals.

[0004] It will also be noted that the “service battery” can be designated by the term “functional battery”, each of these terms being interchangeable and able to be used indifferently to designate this type of battery, which differentiates them from so-called starter batteries. The service battery is connected to the vehicle's storage battery or traction battery, for example via a direct-direct (or DC / DC) converter, to allow the service battery to remain charged and operational and ensure the proper functioning of the vehicle's various functional and / or safety components. Electric or hydrogen vehicles do not have alternators for recharging batteries.

[0005] Thus, when the service battery becomes discharged following a converter problem, a short circuit, external constraints, following use intensive use of the storage and function batteries (causing them to be completely discharged), or following prolonged non-use of the vehicle, it is then necessary to be able to recharge the service battery to allow use and access to certain basic functions of the vehicle.

[0006] More particularly, if the service battery has a voltage value lower than a predetermined value, for example lower than 12V, the various functional and safety components can no longer be activated. The user can therefore no longer use the centralized door opening (only the emergency mechanical key can unlock the driver's door), nor start his vehicle, nor even move it (the electric parking brake being blocked), to take it to the nearest garage for repair. Furthermore, in many cases, it is impossible to lift the vehicle to move it.

[0007] Furthermore, service batteries, generally of the “gel electrolyte” type, generally have electrical constraints. This type of battery cannot withstand current peaks, particularly when they are deeply discharged, unlike conventional lead batteries used in cars with internal combustion engines. It is therefore not possible to use a high-current lead battery charger without risking damaging the service battery of an electric vehicle.

[0008] Furthermore, the service battery of an electric vehicle is very difficult to access for the average user, for reasons of user safety and the warranty of said vehicle.

[0009] Thus, the present invention proposes to resolve at least one of the drawbacks stated above and proposes a new type of electric vehicle battery charger.

[0010] The present invention thus relates to a service battery charger, in particular for an electric vehicle, said charger comprising: - a power source; - an electrical connection configured to connect to the vehicle's service electrical network and connect said electrical power source to the vehicle's battery; - an electrical management circuit configured to limit the intensity of the electrical current flowing, via the service electrical network, from the electrical power source to the vehicle battery.

[0011] Said battery charger according to the invention avoids in particular having to access said battery at the engine compartment, a place where the battery is difficult to access, which sometimes requires dismantling other elements in order to be able to access said service battery. In addition, the charger makes it possible to simply charge the battery and therefore quickly and easily repair an electric vehicle whose service battery is discharged. Furthermore, said charger comprises an electrical management circuit which limits the intensity of the charging current to a predetermined maximum value, for example to 10 amps, and preferably to 8 amps. This limitation of the intensity of the charging current thus makes it possible not to damage the battery (during its charging) or an element of the electrical network of said vehicle.

[0012] According to a possible characteristic, said electrical connection is configured to connect to a cigarette lighter socket and / or to a fused plug.

[0013] It should be noted that a large proportion of vehicles have a so-called cigarette lighter socket, supplied with current and with an intensity of between 10 and 20A, which allows you to light cigars or cigarettes. However, nowadays, these sockets are mainly used to power accessories, such as chargers, vacuum cleaners, inflators, converters to generate 220 V AC, etc. The electrical supply circuit of certain vehicles includes a protective fuse which can adopt two positions at the driver's choice: - a first position called “permanent power supply” in which said cigarette lighter socket is electrically connected to the battery (therefore powered), even when the vehicle is switched off; - a second position called “cut-off”, preventing any electrical connection between said socket and the service battery (therefore not allowing the service battery to be recharged) when the vehicle is switched off (or when the ignition is switched off). Therefore, to recharge the service battery without damaging the fuse located in the first position, it is important to limit the intensity of the service battery recharge current. Additionally, all vehicles include a fuse box, usually located in the passenger compartment of the vehicle. Thus, being able to connect to the cigarette lighter socket when it is operational when the ignition is off or to a fuse plug in a fuse box, simplifies and speeds up the operation of recharging the vehicle battery.

[0014] Furthermore, a configuration with a higher current is possible for vehicles having a higher rating fuse and a battery capable of accepting a higher deep discharge output current (such as batteries fitted to trucks, buses, etc.).

[0015] According to a possible characteristic, said electrical power source is a battery having a nominal voltage higher than the nominal operating voltage of the battery to be charged.

[0016] According to another possible characteristic, said electrical power source comprises one or more of the following elements: cell, battery, capacitor, supercapacitor or any other voltage source or generator.

[0017] According to another possible characteristic, said electrical power source comprises the traction (or storage) battery of said vehicle, said charger being configured to electrically connect to said traction battery.

[0018] According to another possible characteristic, said battery of said charger is an electric battery of the lithium-ion type and preferably multi-element having a nominal voltage of at least 14V, and preferably a nominal voltage of at least 16V. The battery of said charger comprises, for example, 4 lithium-ion cells, arranged in series, each having voltages ranging from 3.5 to 4.2 V and whose dimensions of the pack of 4 cells are, for example, 84x70x21 mm. This embodiment of said electrical power source has the advantages of being particularly economical and compact, while giving the tool advantageous autonomy.

[0019] According to another possible characteristic, said electrical management circuit limits the intensity of the current flowing in said electrical connection (or charging current), said charging current flowing in particular via the electrical service network, according to a predetermined value. To do this, it may comprise a current limiting circuit.

[0020] According to another possible characteristic, said electrical management circuit limits the intensity of the charging current to a predetermined value, such as 10 amps, and preferably 8 amps. This intensity value limits the risk of damage to the service battery to be charged, but also to all the elements of the service electrical network of said vehicle.

[0021] According to another possible characteristic, said electrical management circuit is configured to raise and / or lower the voltage of the electrical power source (in particular a battery). Said electrical management circuit is advantageously configured to raise and / or lower the voltage of the electrical power source so that the output voltage of said electrical management circuit is always adapted to the nominal voltage value of the battery to be charged, and thus to ensure optimal charging of said service battery of the vehicle.

[0022] According to another possible characteristic, said charger comprises a human-machine interface configured to indicate one or more of the following information to the user of said charger: - said charger is switched on; - said charger is charging the vehicle's service battery; - the voltage value of the battery to be charged reaches or exceeds a predetermined voltage value; - the voltage value of the battery to be charged and / or the power supply source; - the power source of said charger is charged and / or exceeds a predetermined voltage value; - the charge and / or voltage value of the power supply source of said charger.

[0023] It will also be noted that said charger can thus be configured to diagnose the service battery by measuring its voltage, such as a measurement of the no-load voltage. Said measurement can be carried out prior to charging and / or during charging after temporary interruption (or suspension) thereof.

[0024] According to another possible characteristic, said charger switches off automatically as soon as the voltage of the battery to be charged exceeds a threshold value. This feature prevents the user from excessively charging the electric vehicle battery and limits misuse of the charger by the user.

[0025] According to another possible characteristic, said charger comprises a USB socket configured to supply electricity to said electrical power source. The battery of the charger can thus be easily recharged via the USB socket.

[0026] Said invention also relates to a charger which is, on the one hand, configured to diagnose said service battery and which is, on the other hand, integrated into the vehicle, said power source of the charger being the traction battery of said vehicle.

[0027] Thus, in the event of excessive discharge of the service battery while the vehicle is stopped, the charger may be engaged, automatically or manually, to maintain a predetermined charge of said service battery (this with an acceptable current) to avoid resulting in a discharge that no longer allows said vehicle to be started. It should also be noted that said charger may also be referred to as a “recharging and diagnostic device” for a motor vehicle service battery.

[0028] The present invention also relates to an electric or hydrogen car, characterized in that said car comprises a service battery charger as defined above, said charger being an on-board system of said vehicle. Said charger according to the invention can thus be integrated into an electric vehicle or hydrogen as a backup system in case of failure of the service battery.

[0029] The present invention also relates to a method for troubleshooting a service battery of an electric or hydrogen vehicle: - connection of an electrical power source to the vehicle's service electrical network; - power supply to the vehicle's service battery via the electrical network, using a current whose intensity is limited to a predetermined value.

[0030] According to a possible characteristic, the method comprises a step of warning the user when the value of the battery voltage has reached a predetermined voltage value.

[0031] According to another possible characteristic, the step of connection to the service electrical network via a cigarette lighter socket and / or a fused plug.

[0032] According to another possible characteristic, the method comprises a step of setting up an electrical access point, in the vehicle, to the service battery, in order to establish an electrical connection between a third-party device, such as a recharging or diagnostic device and said service battery.

[0033] According to another possible characteristic, the fuse connecting the cigarette lighter socket to the battery is positioned in a so-called “permanent power supply” position, that is to say in a position in which said cigarette lighter socket is electrically connected to the battery (therefore powered), even when the vehicle is switched off.

[0034] The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly during the following description of particular embodiments of the invention, given solely for illustrative and non-limiting purposes, with reference to the appended drawings, in which: [Fig.l] is a very schematic representation of a first embodiment of a battery charger according to the invention; [Fig.2] is a very schematic representation of a second embodiment of a battery charger according to the invention; [Fig.3] is a schematic perspective representation of the charger of [Fig.l] connected to the service electrical network of a vehicle via a cigarette lighter socket, and [Fig.4] is a schematic perspective representation of the charger of [Fig.l] connected to the service electrical network of a vehicle via a fused plug.

[0035] [Fig.l] is a very schematic representation of a first embodiment of a battery charger 1 for an electric vehicle V.

[0036] The battery charger 1 thus comprises: - a power supply source 3; - an electrical connection 5 which is configured to connect to the electrical network R of the vehicle V and which comprises two electrical cables 5a and 5b and a connector 5c; - an electrical (and / or electrotechnical) management circuit 7 configured to limit the intensity of the output electrical current I0Ut (or charging) circulating, via said electrical connection 5, from the electrical power source 3 to an electric battery B of the vehicle V; - a voltmeter 9 configured to measure the voltage (or an image of the voltage) of battery B to be charged; - a human-machine interface 11 which is configured to indicate one or more pieces of information to the user of said charger 1, and which is in particular connected to said voltmeter 9.

[0037] It will also be noted that said charger 1 possibly comprises an electronic management circuit (not shown) for the various elements mentioned above.

[0038] It will be noted that said management circuit 7 can be integrated into the cable 5a of the connection 5 connecting the positive terminal of the power source 3 to the positive terminal of the battery B of the vehicle or be a separate element interposed between said cable 5a and the power source 3. The cable 5b, for its part, connects the negative terminal of the power source 3 to the negative terminal of the battery B of the vehicle.

[0039] In the present embodiment, said power source 3 is an electric battery comprising four lithium-ion type cells 3a, arranged in series, each having a voltage of approximately 4V. The dimensions of the pack of 4 cells 3a are approximately 84x70x21mm.

[0040] The electric battery 3 of the charger 1 therefore has a nominal voltage Ui of approximately 16 volts, while an electric vehicle service battery has a usual nominal voltage U2 of approximately 12V. Thus, the battery 3 has a nominal voltage Ui greater than the nominal operating voltage U2 of the battery B to be charged of the electric vehicle V.

[0041] Said charger further comprises a USB socket (not shown) configured to supply electricity to said electrical power source 3. In the present embodiment, said USB socket thus makes it possible to recharge the battery 3 of the charger 1.

[0042] Said electrical management circuit 7 is, for its part, configured to limit the intensity of the output (or charging) current IOut, which flows from the battery 3 of the charger 1 to the battery B of the vehicle V, to a predetermined maximum value Imax. Advantageously, the predetermined maximum value Imax is 10 amps, and preferably 8 amps.

[0043] Said electrical management circuit 7 comprises, for this purpose, a limiting circuit of current which includes: - a TH transistor such as a MOSFET or bipolar transistor, the drain (or collector) of which is connected to the positive terminal of the battery 3 of the charger; - a resistor Ri connected to the source (or emitter) of the transistor Ti; - a reference voltage source 7a delivering a voltage Vref; - an operational amplifier AOi whose output is connected to the gate (or base) of the transistor, the inverting input is connected to a node Ni located between the source of the transistor Ti and the resistor Rb and whose non-inverting input is connected to the output of the reference voltage source 7a.

[0044] It will be noted that the input of the reference voltage source 7a is connected to a node N2 itself connected to one of the terminals of the resistor RB, said resistor Ri having each of its terminals connected respectively to the nodes Ni and N2.

[0045] Thus, the elements listed above allow linear regulation of the output current IOut (or charging). Indeed, the operational amplifier AOi amplifies the difference between the voltages received at its inputs (inverting and non-inverting) and delivers at output a voltage which thus regulates the quantity of current which flows through the transistor T i (and therefore generally the quantity of current flowing from the battery 3 of the charger 1 to the battery B of the vehicle). By carefully choosing the values ​​of the resistance Ri and the reference voltage Vref, we obtain a circuit 7 which limits the current intensity to a predetermined value Imax. For example, for Ri = 0.1 Q and Vref = 0.8 V, we will have Imax = 8 A.

[0046] The human-machine interface 11 comprises, for its part, one or more light indicators, such as light-emitting diodes (or LEDs), which turn on or off to indicate to the user the state of the charger and / or the state of the vehicle battery. It could also indicate a charging state, for example by a set of colors of the light-emitting diodes.

[0047] The human-machine interface 11 can therefore indicate whether: - the charger is switched on and ready for use; - said charger is charging the vehicle battery, in particular the service battery; - the voltage value of the battery to be charged reaches or exceeds a predetermined voltage value, for example the theoretical nominal operating voltage of said battery to be charged.

[0048] In an alternative embodiment not shown, the human-machine interface comprises a screen indicating the states mentioned above. The said screen may also indicate: - the charge and / or voltage value of the vehicle battery and / or the electrical power source. - the power source of said charger is charged or exceeds a predetermined voltage value.

[0049] Thus, the user can proceed, by means of said charger 1, to the repair of an electric (or hydrogen) vehicle whose functional battery B needs to be recharged. The user, after mechanically unlocking one of the vehicle doors, connects, by means of the electrical connection 5, the charger 1 to the electrical network R of the vehicle V. The connection with the electrical network R of the vehicle V can be made in different ways, for example via the cigarette lighter socket P, as illustrated in [Fig.3], or via a fused plug F, as illustrated in [Fig.4].

[0050] More particularly, in [Fig. 3], said electrical connection 5 then comprises a connector 5d configured to cooperate with the cigarette lighter socket P. In the embodiment of [Fig. 4], said electrical connection 5 comprises a connector 5e configured to cooperate with the fuse plug F (in particular located in the fuse box of the vehicle V) and a ground connector 5f configured to attach to an element G, in particular of the vehicle V, acting as electrical ground.

[0051] It will be noted that it is sometimes necessary for the fuse of the cigarette lighter socket to be in a so-called “permanent power supply” position to allow the charger according to the invention to operate when the vehicle is switched off. After using the charger, the fuse can be returned to a so-called "cut-off" position or advantageously left in the permanent power supply position.

[0052] It should also be noted, in the case of an electrical connection via a fused plug, that it is necessary to select a part of the electrical network suitable for the currents to be injected and to first remove the existing fuse.

[0053] The charger 1 then indicates, via the human-machine interface 11 (such as an indicator light), that the charger 1 is charging the vehicle's functional battery B. Once the vehicle's battery B reaches a predetermined voltage value, such as its nominal operating voltage U2, the human-machine interface indicates to the user that the function battery B is charged and that the user can start the electric vehicle V. It will be noted that beforehand, said human-machine interface 11 can also indicate, for example by means of an indicator light, that the charger 1 is functional and capable of charging said battery B of the vehicle.

[0054] In an alternative embodiment not shown, the charger switches off automatically- automatically as soon as the voltage of the battery to be charged exceeds a threshold value.

[0055] [Fig. 2] is a very schematic representation of a second embodiment of a charger 10 according to the invention. The same elements bear the same references as in the first embodiment and will therefore not be detailed again.

[0056] Thus, unlike the first embodiment, said electrical management circuit 27 is configured, on the one hand, to limit the intensity of the current I0Ut at the output of the charger 10, and, on the other hand, to raise and / or lower the output voltage VOut of said charger 10.

[0057] More particularly, said electrical management circuit 27 is advantageously configured to raise and / or lower the voltage of the electrical power source so that the output voltage VOut of said electrical management circuit 27 is always adapted with respect to the value of the nominal voltage of the battery B to be charged. It will be noted that generally the electrical management circuit 27 raises the voltage received by the battery from the charger 3 so that the output voltage VOut is greater than the nominal voltage U2 of the battery B to be charged.

[0058] More particularly, said electrical management circuit 27 comprises: - a transformer 21 connected to the terminals of the battery 3 of the charger 10, via a transistor T2; - a control circuit 23 connected to the transistor T2, more particularly at the level of the gate of the transistor T2, configured to limit the intensity of the output current IOut and regulate the value of the output voltage VOut; - a rectification and filtering circuit 29 which itself comprises a diode Di and a capacitor Ci, configured so that the output voltage VOut is a direct voltage.

[0059] More particularly, the source of transistor T2 is connected to the negative terminal of battery 3 of charger 10, while the drain of transistor T2 is connected to transformer 21.

[0060] Said transistor T2 is controlled by the control circuit 23 which is itself controlled by the output voltage VOut and the output current IOUt. Said control circuit 23 also has setpoint values ​​for the output voltage VOut and current I0Ut, for example 16 V and 8 A. Thus, said control circuit 23, as a function of the output voltage VOut and current I0Ut values ​​and the setpoint voltage and current, regulates the gate voltage of transistor T2, which causes the modulation of the source-drain current until the output voltage and current correspond to the setpoint voltage and current values.

[0061] The present invention also relates to an electric or hydrogen motor vehicle which comprises a battery charger as described above, said charger being an on-board system of said vehicle.

[0062] When the charger is integrated into a motor vehicle, it is advantageous for it to be, on the one hand, configured to diagnose said service battery and, on the other hand, integrated into the vehicle, said power source of the charger then advantageously being the traction battery of said vehicle. Said charger may also comprise another electrical power source, such as a battery, etc. Said integrated charger is thus configured to engage, automatically or manually, to maintain a predetermined charge of said service battery, in order to avoid a discharge of the service battery no longer allowing the starting of said vehicle.

Claims

Claims

1. Charger (1; 10) for an electric vehicle service battery, said charger comprising: - an electrical power source (3); - an electrical connection (5) configured to connect to the vehicle's service electrical network and connect said electrical power source (3) to the vehicle's service battery; - an electrical management circuit (7; 27) configured to limit the intensity of the electric current (Iout) flowing, via the service electrical network, from the electrical power source (3) to the vehicle's service battery, characterized in that said electrical connection (5) comprises a connector (5d, 5e) configured to cooperate with a cigarette lighter socket and / or a fused plug, and in that said electrical management circuit (7; 27) limits the intensity of the charging current (IOut) to a predetermined value.

2. Charger according to claim 1, characterized in that the electrical power source (3) is a battery having a nominal voltage (Ui) higher than the nominal operating voltage (U2) of the service battery to be charged.

3. Charger according to the preceding claim, characterized in that said battery (3) is an electric battery of the lithium-ion type having a nominal voltage (Ui) of at least 14V, and preferably a nominal voltage of at least 16V.

4. Charger according to any one of the preceding claims, characterized in that said electrical management circuit (7; 27) is configured to raise the voltage and / or lower the voltage of the electrical power source (3).

5. Charger according to any one of the preceding claims, characterized in that it comprises a human-machine interface (11) configured to indicate one or more of the following information to the user: - said charger is switched on; - said charger is charging the service battery of the vehicle; - the voltage value of the service battery to be charged reaches or exceeds a predetermined voltage value; - the voltage value of the service battery to be charged and / or of the electrical power source; - the electrical power source of said charger is charged and / or exceeds a predetermined voltage value; - the charge and / or the voltage value of the electrical power source of said charger.

6. Charger according to any one of the preceding claims, characterized in that said charger (1) switches off automatically as soon as the voltage of the service battery to be charged exceeds a threshold value.

7. Charger according to any one of the preceding claims, characterized in that said charger (1) comprises a USB socket configured to supply electricity to said electrical power source (3).

8. Charger according to any one of the preceding claims, characterized in that it is, on the one hand, configured to diagnose said service battery and, on the other hand, to be integrated into the vehicle, said power source of the charger being the traction battery of said vehicle.

9. Method for troubleshooting a service battery of an electric or hydrogen vehicle by means of a charger (1, 10) according to any one of the preceding claims, said method comprising the following steps: - connecting an electrical power source to the service electrical network of the vehicle; - supplying the service battery of the vehicle via the electrical network, with a current whose intensity is limited to a predetermined value; characterized in that the connection of the electrical power source to the service electrical network comprises the cooperation of the connector (5d, 5e) with a cigarette lighter socket and / or a fused plug.

10. Method according to the preceding claim, characterized in that there is a warning to the user when the voltage value of the service battery has reached a predetermined voltage value.

11. Method according to claim 9, characterized in that there is a step of setting up an electrical access point in the vehicle to the service battery, in order to establish an electrical connection between a third-party device, such as a device for recharging and diagnosing said battery of servitude.

Images