Electrical power supply system for consumers of an electric or hybrid vehicle and method for managing the power supply of a vehicle

Abstract

Electrical power supply system for consumers of an electric or hybrid vehicle and method for managing the power supply of a vehicle The present invention relates to an electrical power supply system (1) for consumers of an electric or hybrid vehicle, comprising: - a traction battery (8) capable of supplying the energy necessary for the operation of an electric powertrain of the vehicle, - power switches (14, 16, 18) capable of connecting the traction battery (8) to the electric powertrain, - a service battery (6), connected to an on-board network (4) of the vehicle, - a direct current - direct current converter (2) capable of recharging the service battery (6) and connected at the input to the traction battery (8) and at the output to the on-board network (4) of the vehicle, the direct current - direct current converter (2) being connected upstream of the power switches (14, 16, 18). (Figure 1)

Description

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

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

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

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

[0004] The service battery only needs to be changed every three to four years, and is therefore used to power at least the vehicle's consumers during long periods of non-use, i.e. when the vehicle is stationary and switched off. It is then said to be "asleep" because in reality during these periods of non-use, the vehicle's computers have consumers remaining activated to monitor the vehicle's environment, such as an alarm, a communication module of a computer to receive radio signals from an ignition key, or messages from a remote server via a wireless communication network, requesting for example the sending of maintenance data or the updating of software.

[0005] This consumption of vehicles during periods of inactivity is also likely to increase over time, particularly due to the entry of vehicles into the Internet of objects. As a result, the service battery tends to discharge faster than before, and to overcome this problem, manufacturers oversize the service batteries or recharge them regularly from the energy stored in the high-voltage battery, which requires at least a partial wake-up of the vehicle. The first solution adds mass and bulk to the vehicle's engine compartment, which is not desirable. The second solution requires additional energy consumption due to waking the vehicle and the procedures for checking the high-voltage network before connecting a DC-DC converter to the high-voltage battery, the converter allowing the service battery to be recharged.

[0006] The present invention aims to remedy at least in part the drawbacks of the technique by providing a system for supplying electricity to consumers of an electric or hybrid vehicle, a vehicle equipped with such a system and a method for managing the power supply of the on-board network of such a vehicle, which make it possible to reduce the energy consumption necessary for recharging a service battery of the vehicle by a high-voltage battery of the vehicle, during long periods of non-use of the vehicle.

[0007] To this end, the invention proposes a system for supplying electricity to consumers of an electric or hybrid vehicle, comprising: - a battery pack comprising a traction battery capable of supplying the energy necessary for the operation of an electric powertrain of the vehicle, - power switches capable of connecting the traction battery to power buses extending outside the battery pack, - a service battery, connected to the vehicle's on-board network, - a direct current - direct current converter capable of recharging the service battery, the direct current - direct current converter being connected at the input to the traction battery and at the output to the vehicle's on-board network, the electrical power supply system being characterized in that the direct current - direct current converter is connected in parallel to the traction battery at connection points located between the traction battery and the power switches.

[0008] It should be noted that in this application, the traction battery is understood as a battery of electric accumulators supplying an inverter and an electric motor when the vehicle is running, unlike the vehicle's service battery supplying the vehicle's on-board network to which various consumers are connected, including a main computer of the vehicle. The traction battery can therefore also be understood as a propulsion battery depending on the electric motor used, this being an electric motor allowing traction or propulsion of the vehicle, possibly in cooperation with another type of engine if the vehicle is hybrid, understood in the sense of “electric hybrid” in this application.

[0009] Furthermore, it should be noted that the terms "upstream" or "downstream" in this application refer to the relative position of electrical components or assemblies with respect to the direction of the current leaving the battery and heading towards the consumers of the vehicle. Thus, a first component is upstream of a second component if the current leaving the battery first passes through the first component and then the second component before returning to the traction battery.

[0010] Thanks to the invention, the direct current - direct current converter being connected upstream of the power switches, the direct current - direct current converter can recharge the service battery without requiring the power switches to be closed. This saves energy, which would otherwise be spent before closing these switches, to check that safety conditions of the high voltage network are respected, these conditions being able to be the absence of access by a user to the high voltage network, corresponding for example to the closing of a high voltage charging hatch, or even the electrical isolation of the traction battery with respect to a chassis of the vehicle.

[0011] According to a preferred characteristic of the invention, the battery pack comprises a housing housing the traction battery, the direct current - direct current converter and the power switches. The integration of the direct current - direct current converter and the power switches in the battery pack electrically isolates them from the chassis and protects them from impacts. It therefore contributes to the electrical safety of the electrical power supply system according to the invention, and avoids energy expenditures necessary without this safety, before authorizing the operation of the direct current - direct current converter or the closing of the switches.

[0012] In one embodiment of the invention, a first output of the direct current - direct current converter is connected to a power supply bus of the on-board network, and a second output of the direct current - direct current converter is connected to a ground of the vehicle. The electrical power supply system according to the invention further comprises an electronic device for controlling the direct current - direct current converter, integrated into the battery pack and having a power supply input connected to the first output of the direct current - direct current converter, in the battery pack. Thus the control electronic device and its power supply are secured. In particular in the event of a crash, the on-board network can continue to be powered by the traction battery as long as the battery pack is not too damaged.

[0013] Advantageously, the electrical power supply system according to the invention comprises a traction battery management module, integrated into the battery pack. This management module monitors the condition of the traction battery cells and can open the power switches or deactivate the DC-DC converter in the event of a traction battery fault.

[0014] In one embodiment of the invention, the power switches comprise a positive power switch, a negative power switch, and a precharging system connected in parallel with the positive power switch, the precharging system comprising a precharging resistor and a precharging switch. The precharging system makes it possible to avoid the formation of an excessively high current draw when connecting the traction battery to a battery charger or to a charging terminal comprising input inductances or capacitances.

[0015] Alternatively, if the switches are implemented by transistors and not relays, the precharge system is not necessary.

[0016] Furthermore, the positive and negative power switches are preferably each equipped with a fuse device connected between the traction battery and the positive or negative power switch.

[0017] The electrical power supply system according to the invention advantageously comprises a device for supervising the electric or hybrid vehicle, connected to the on-board network and comprising means for verifying safety conditions of a high-voltage network of the vehicle, capable of activating means for closing the power switches. Thus, the electrical power supply system according to the invention manages both the power supply of the on-board network and the power supply of the high-voltage network. The electrical power supply system according to the invention may also comprise the on-board network of the vehicle, or on the one hand the connection between the service battery and the on-board network and on the other hand the connection between the direct current - direct current converter and the on-board network.

[0018] The invention also relates to a method for managing the power supply of the on-board network of a vehicle equipped with an electrical power supply system according to the invention, comprising a step of powering the on-board network by the service battery and by the direct current - direct current converter, the power switches being open. This power supply step is followed by the following steps when the high voltage network needs to be powered:

[0019] - detection of a request to activate high voltage equipment of the vehicle, - verification of safety conditions related to the vehicle's high voltage network, and - closing of the power switches following the detection step. The invention finally relates to an electric or hybrid vehicle equipped with an electrical power supply system according to the invention.

[0020] The electric vehicle according to the invention and the management method according to the invention have advantages similar to those of the electrical power supply system according to the invention.

[0021] Other characteristics and advantages of the invention will become apparent from the following description on the one hand, and from several exemplary embodiments given for informational and non-limiting purposes with reference to the appended schematic drawings on the other hand, in which:

[0022] [Fig.l] schematically represents an electrical power supply system according to the invention, in an embodiment according to the invention, and

[0023] [Fig.2] represents steps of a method for managing the power supply of a network of a vehicle equipped with the electrical power supply system of [Fig.l], in this embodiment of the invention.

[0024] In one embodiment of the invention, an electrical power supply system 1, shown [Fig.l] and equipping an electric or hybrid vehicle, comprises a battery 8 of electrical accumulators, for example a Lithium-ion traction battery. The traction battery 8 is connected in parallel at the input of a direct current - direct current converter 2 capable of converting the voltage at the terminals of the traction battery 8, of the order of 200 to 800V (Volts), into a voltage of the order of 14V at the output of the direct current - direct current converter 2.

[0025] A first output terminal of the direct current - direct current converter 2 is connected to a positive output terminal of a service battery 6 supplying an on-board network 4 of the vehicle, via a fuse box 7 to which low-voltage consumers of the vehicle are connected, such as lighting devices, computers, window regulator actuators, etc. The service battery 6 has, in this embodiment of the invention, a maximum no-load voltage of 14V. Alternatively, the service battery and the output of the direct current - direct current converter have different output voltages, for example of the order of 12V or even 48V.

[0026] A second output terminal of the DC-DC converter 2 is connected to a vehicle ground. The negative output terminal of the service battery is also connected to the vehicle ground by a different connection point than that of the second output terminal of the DC-DC converter 2.

[0027] An electronic control device 20 for the direct current - direct current converter 2 controls the operation thereof. In particular, as soon as the voltage of the on-board network 4 falls below a predetermined regulation voltage of the direct current - direct current converter 2, for example set at 13V, then the electronic control device 20 operates the direct current - direct current converter 2 which then recharges the battery of servitude 6 while participating in the supply of the on-board network 4.

[0028] The electronic control device 20, which is for example a microcontroller, is powered by the on-board network 4 at the output of the direct current - direct current converter 2, inside a battery pack 3 integrating the traction battery 8, the direct current - direct current converter 2 and the electronic control device 20.

[0029] The battery pack 3 of the electrical power supply system 1 is a crash-resistant housing that electrically insulates its internal components having high voltage from the rest of the vehicle, except of course at the high voltage outputs of the battery pack 3, which are on the one hand a positive high voltage connection terminal 12 and on the other hand a negative high voltage connection terminal 22. The battery pack 3 also has a low voltage output connected on the one hand to the first output terminal of the direct current - direct current converter 2 and on the other hand to the on-board network 4. The battery pack 3 also has a connection to the ground of the vehicle to connect the second output terminal of the direct current - direct current converter 2.

[0030] The “high voltage” here concerns the components operating at more than 200V, i.e. the traction battery 8 and the consumers directly powered by it, while the “low voltage” concerns the 14V on-board network and its consumers.

[0031] The battery pack 3 also comprises a CAN bus output 52 (from the English “Controller Area Network”) making it possible to connect the control electronics device 20 to a supervision device 5 of the vehicle, which is for example the main computer of the vehicle. The supervision device 5 of the vehicle can thus activate or deactivate the control electronics device 20 and the direct current - direct current converter 2 in the wake-up phase or respectively in the sleep phase of the vehicle.

[0032] The battery pack 3 also incorporates power switches 14, 16, 18 capable of connecting the traction battery 8 to the high-voltage connection terminals 12, 22, downstream of the direct current - direct current converter 2. The power switches 14, 16, 18 are therefore capable of connecting the traction battery 8 to the high-voltage components of the vehicle, such as the electric powertrain of the vehicle.

[0033] More precisely, in the battery pack 3, a first connection point common to the traction battery 8 and to the direct current - direct current converter 2 is connected to one end of a first fuse 15, the other end of which is connected to a first terminal of a positive power switch 14, the second terminal of the positive power switch 14 being connected to the positive high voltage output connection terminal 12 of the battery pack 3. The other end of the first fuse 15 is also connected to a precharging system connected in parallel to the positive power switch 14, this precharging system comprising in series a precharging resistor 19 and a precharging switch 18.

[0034] Similarly in the battery pack 3, a second connection point common to the traction battery 8 and to the direct current - direct current converter 2 is connected to one end of a second fuse 17, here a pyroswitch, the other end of which is connected to a first terminal of a negative power switch 16, the second terminal of the negative power switch 16 being connected to the negative high voltage output connection terminal 22 of the battery pack 3.

[0035] Finally, the battery pack 3 also integrates a management module 32 of the traction battery 8, monitoring in particular the temperature and the voltage of the cells of the traction battery 8, and capable of opening the power switches 14, 16, 18 in the event of a fault. The management module 32 is hardware and software, and may in particular include temperature sensors and / or one or more pre-programmed electronic circuits. The management module 32 is connected by the CAN bus output 52 to the supervision device 5 of the vehicle.

[0036] A method 100 for managing the power supply of the on-board network 4 of the vehicle is now described with reference to [Fig. 2]. The management method 100 is implemented in particular by the supervision device 5 of the vehicle, and the electronic control device 20.

[0037] A first step 110 is the power supply of the on-board network 4 by the service battery 6 and by the direct current - direct current converter 2, the power switches 14, 16, 18 being open. In other words, in this first step 110, we are in an initial situation of recharging the service battery 6, without the high voltage network of the vehicle being powered by the traction battery 8. This step takes place for example in a parking phase of the vehicle, during which the latter is "awakened", the supervision device 5 of the vehicle allowing "life on board" not requiring significant electrical consumption.In particular during this power supply step 110, a car radio, a vehicle dashboard camera can operate, the vehicle being able to transmit data, update software or check the state of the traction battery 8, without microcontrollers linked to the high voltage, such as those of the inverter, the charger or the air conditioning compressor, being powered.

[0038] This power supply step 110 can take place even when the high voltage network has a fault preventing its use (for example a power switch stuck open), which allows the service battery 6 not to discharge too quickly before the vehicle is repaired. Similarly, during an accident affecting the vehicle, the high voltage network must be cut off, but thanks to the invention, the step power supply 110 allows the on-board network 4 to operate for longer and, for example, to make an emergency call or to leave lighting devices on even when the service battery 6 is disconnected from the on-board network 4.

[0039] A second step 120 is a step of detecting a request to activate high-voltage equipment of the vehicle. This detection step 120 takes place for example when a user connects an electric charging cable to the vehicle, or during a request for torque at the wheel, or even during a request to preheat the passenger compartment.

[0040] The following step 130 is then the verification of safety conditions linked to the high voltage network of the vehicle, such as the absence of faults in the power switches, the verification of the quality of an earth connection to which the vehicle is connected, etc. It is assumed, in this example of use of the invention, that these safety conditions are met.

[0041] The next step 140 is then the closing of the precharge switch 18 and the negative power switch 16, then the closing of the positive power switch 14 and the opening of the precharge switch 18.

[0042] The next step 150 is the power supply of the high voltage equipment of the vehicle.

[0043] Finally, once the vehicle's high voltage network is no longer in demand, the supervision device 5 opens 160 the power switches 14, 16, the management method returning to the first step 110 of supplying the on-board network without supplying the high voltage network.

[0044] Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention.

Claims

Claims

1. Electrical power supply system (1) for consumers of an electric or hybrid vehicle, comprising: - a battery pack (3) comprising a traction battery (8) capable of supplying the energy necessary for the operation of an electric powertrain of the vehicle, - power switches (14, 16, 18) capable of connecting the traction battery (8) to power buses extending outside the battery pack (3), - a service battery (6), connected to an on-board network (4) of the vehicle, - a direct current - direct current converter (2) capable of recharging the service battery (6), the direct current - direct current converter (2) being connected at the input to the traction battery (8) and at the output to the on-board network (4) of the vehicle,the direct current - direct current converter (2) being connected in parallel to the traction battery (8) at connection points located between the traction battery and the power switches (14, 16, 18), the electrical power supply system (1) being characterized in that a first output of the direct current - direct current converter (2) is connected to a power supply bus of the on-board network (4), a second output of the direct current - direct current converter (2) is connected to a ground of the vehicle, and in that it comprises an electronic control device (20) of the direct current - direct current converter (2), integrated in the battery pack (3) and of which a power supply input is connected to the first output of the direct current - direct current converter (2), in the battery pack (3).,

2. Power supply system (1) according to claim 1, characterized in that the battery pack (3) comprises a housing housing the traction battery (8), the direct current - direct current converter (2) and the power switches (14, 16, 18).

3. Electrical power supply system (1) according to claim 1 or 2, characterized in that it comprises a management module (32) of the traction battery (8), integrated in the battery block (3).

4. Power supply system (1) according to any one of claims 1 to 3, characterized in that the power switches (14, 16, 18) comprise a positive power switch (14), an in- negative power switch (16), and a precharge system connected in parallel with the positive power switch (14), the precharge system comprising a precharge resistor (19) and a precharge switch (18).

5. Power supply system (1) according to claim 4, characterized in that the positive (14) and negative (16) power switches are each equipped with a fuse device (15, 17) connected between the traction battery (8) and the positive (14) or negative (16) power switch.

6. Electrical power supply system (1) according to any one of claims 1 to 5, characterized in that it comprises a supervision device (5) of the electric or hybrid vehicle, connected to the on-board network (4) and comprising means for verifying safety conditions of a high voltage network of the vehicle, capable of activating means for closing the power switches (14, 16, 18).

7. Method (100) for managing the power supply of the on-board network (4) of a vehicle equipped with an electrical power supply system (1) according to any one of claims 1 to 6, comprising a step (110) of powering the on-board network (4) by the service battery (6) and by the direct current - direct current converter (2), the power switches (14, 16, 18) being open.

8. Method for managing (100) the power supply of the on-board network (4) of a vehicle according to the preceding claim taken in the dependency of claim 6, in which the power supply step is followed by the steps of: - detecting a request to activate high voltage equipment of the vehicle, - verifying safety conditions linked to the high voltage network of the vehicle, and - closing the power switches following the detection step.

9. Electric or hybrid vehicle equipped with an electrical power supply system (1) according to any one of claims 1 to 6.

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