METHOD FOR REGULATING THE OUTPUT VOLTAGE OF A DC-DC VOLTAGE CONVERTER IN A MOTOR VEHICLE

Abstract

The invention relates to a method for regulating the output voltage (Ureg) of a DC-DC converter in a motor vehicle, comprising a step of measuring the temperature of the 12V battery (B12V) by said temperature sensor (CT), the measured temperature (Tbat) being transmitted to the battery voltage control unit (BVCU); a step of transmitting the temperature (Tbat) from the battery voltage control unit (BVCU) to the on-board charger (OBC) via a communication gateway; and a step of regulating the output voltage (Ureg) emitted by said on-board charger (OBC) to said 12V battery (B12V), said output voltage (Ureg) being determined as a function of the temperature (Tbat) by the on-board charger (OBC). Figure 1

Description

Title of the invention: METHOD FOR REGULATING THE OUTPUT VOLTAGE OF A DC-DC VOLTAGE CONVERTER IN A MOTOR VEHICLE

[0001] The invention relates to the management of 12V batteries in motor vehicles.

[0002] Prior art patent application CN113054288, which describes a method for heating a vehicle battery, is known. The vehicle comprises a heating module, a DC-DC converter module, and a battery. The DC-DC converter module amplifies a first direct current supplied by the battery to obtain a second direct current. The second direct current is supplied to the heating module to heat the battery. The second direct current can be amplified to form a third direct current. The DC-DC converter module enters a voltage reduction mode when the battery temperature exceeds a threshold value. In reduction mode, the DC-DC converter module controls the reduction of the third direct current to obtain the first direct current. The first direct current is a low-voltage current, while the third direct current is a high-voltage current.However, one drawback remains. The reduction mode is activated when the temperature exceeds a single threshold value. Thus, the current is not actually adjusted according to the battery temperature, but only in the event of overheating. This is likely to reduce the battery's performance and, in the long term, damage it.

[0003] The objective of the present invention is to remedy these drawbacks and to improve the performance, safety and lifespan of the 12V battery.

[0004] To achieve this objective, the invention proposes a method for regulating the output voltage of a DC-DC voltage converter of a motor vehicle, said vehicle comprising a 48V traction battery, a 12V battery and a battery voltage control unit, said 48V traction battery comprising a temperature sensor, said DC-DC voltage converter comprising an on-board charger, characterized in that said method comprises the following steps: - a step of measuring the temperature of the 48V traction battery by said temperature sensor, the measured temperature being transmitted to the battery management system, said temperature being transmitted by the battery management system to the battery voltage control unit; - a temperature transmission step from the battery voltage control unit to the on-board charger via a communication gateway; - a step of regulating the output voltage emitted by said on-board charger to said 12V battery, said output voltage being determined according to the temperature by the on-board charger.

[0005] Thanks to the invention, the voltage for recharging the 12V battery is adapted so as to prolong its lifespan and improve its performance.

[0006] Advantageously, during said determination step, the output voltage is between 14V and 15.2V.

[0007] Advantageously, said 12V battery has a capacity of 4 amp-hours.

[0008] Thus, the 12V battery is undersized compared to conventional 12V batteries. This makes it possible to reduce the overall weight of the vehicle.

[0009] Furthermore, the invention relates to a computer program comprising instructions which, when the program is executed by a computer, lead the latter to implement the steps of the method of regulating the output voltage of a DC-DC voltage converter of a motor vehicle previously described.

[0010] The invention also relates to a motor vehicle configured to implement the method of regulating the output voltage of a DC-DC voltage converter of a motor vehicle previously described.

[0011] The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures illustrating variants of the invention, in which: - [Fig.l] schematically illustrates the interactions between the components of a motor vehicle to implement a process for regulating the output voltage of a DC / DC voltage converter; - [Fig.2] illustrates, in the form of a table, the appropriate output voltage for recharging the 12V battery as a function of the temperature of the 48V traction battery.

[0012] The invention relates to a method for regulating the output voltage Ureg of a DC / DC voltage converter in a motor vehicle. The vehicle includes a 48V BT traction battery, a 12V B12V battery, a battery management system (BMS), and a battery voltage control unit (BVCU). The 12V B12V battery's role in all types of motor vehicles is, in particular, to power the headlights, infotainment system, electrical safety devices, and ventilation and heating systems. Preferably, the 12V B12V battery has a capacity of 4 amp-hours, which allows for a reduction in the size of said battery. The 12V B12V battery saves space and reduces the vehicle's overall weight. In a conventional internal combustion engine vehicle, the 12V B12V battery provides the energy needed to power the starter motor, thus starting the engine. In an electric or hybrid vehicle, the 12V battery is essential for maintaining safety functions, including controlling the Battery Management System (BMS) when the vehicle is off or in the event of a traction battery failure. The BMS is a crucial component for monitoring, protecting, and optimizing the use of the 12V B12V battery. This improves the battery's lifespan, safety, and performance. The 12V B12V battery consists of at least one module containing multiple electrochemical cells.The battery voltage control unit (BVCU) monitors the voltage of each module or electrochemical cell to prevent any one module or cell from having a significant charge difference compared to the others. The DC-DC converter is an electronic device that converts a first DC voltage into a second DC voltage, the second DC voltage being different from the first. The second DC voltage is either higher or lower than the first DC voltage. The DC-DC converter includes an onboard charger configured to convert electrical energy from an external source into usable electrical energy for the 12V battery.

[0013] The method comprises a plurality of steps. In a measurement step, the temperature Tbat of the 48V BT traction battery is measured by the CT temperature sensor. As illustrated in [Fig. 1], the temperature Tbat is then transmitted to the battery management system (BMS), which redirects the temperature data Tbat to the battery voltage control unit (BVCU). In a transmission step, the BVCU transmits the temperature data Tbat to the on-board charger (OBC) of the DC-DC converter. The transfer of the temperature data Tbat is ensured by a communication gateway. The communication gateway is a device or software that interconnects different computer networks to allow the transfer and translation of data between them.During a regulation step, the appropriate output voltage Ureg for recharging the 12V B12V battery is determined based on the temperature Tbat of the 48V BT traction battery measured during the measurement step. Figure 2 illustrates, in tabular form, the appropriate output voltage Ureg as a function of the temperature Tbat of the 48V BT traction battery. For example, when... The 48V BT traction battery has a temperature of 40°C, so the appropriate output voltage Ureg for charging the 12V B12V battery is 14.3V. During the determination stage, the output voltage Ureg is between 14V and 15.2V. Therefore, the on-board charger (OBC) determines the appropriate output voltage Ureg and delivers an electrical current at that voltage to the 12V B12V battery to recharge it.

[0014] The invention also relates to a computer program configured to implement said method for regulating the output voltage Ureg of a DC / DC converter in a motor vehicle. Furthermore, the invention relates to a motor vehicle comprising a computer configured to implement said method described above.

Claims

Demands

1. Method for regulating an output voltage (Ureg) of a DC / DC voltage converter of a motor vehicle, said vehicle comprising a 48V traction battery (BT), a 12V battery (B 12V) and a battery voltage control unit (BVCU), said 48V traction battery (BT) comprising a temperature sensor (CT), said DC / DC voltage converter comprising an on-board charger (OBC), characterized in that said method comprises the following steps: - a step of measuring the temperature of the 48V traction battery (BT) by said temperature sensor (CT), the measured temperature (Tbat) being transmitted to the battery management system (BMS), said temperature (Tbat) being transmitted by the battery management system (BMS) to the battery voltage control unit (BVCU);- a step of transmitting the temperature (Tbat) from the battery voltage control unit (BVCU) to the on-board charger (OBC) via a communication gateway; - a step of regulating the output voltage (Ureg) emitted by said on-board charger (OBC) to said 12V battery (B 12V), said output voltage (Ureg) being determined as a function of the temperature (Tbat) by the on-board charger (OBC).

2. The method according to claim 1 characterized in that, during said determination step, the output voltage (Ureg) is between 14V and 15.2V.

3. Method according to claim 1 or 2 characterized in that said 12V battery (B 12V) has a capacity of 4 ampere-hours.

4. A computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the steps of the method for regulating the output voltage (Ureg) of a DC-DC voltage converter of a motor vehicle according to any one of claims 1 to 3.

5. Motor vehicle configured to implement the output voltage regulation (Ureg) method of a converter direct-direct (DC / DC) voltage according to any one of claims 1 to 3.

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