US-12623561-B2 - Power supply system for vehicle and control method

Abstract

A power supply system includes a charging controller, in which, when a soak time representing a period of time elapsed after an off operation has been received is shorter than a first period of time that is determined beforehand, a coupling state detector has detected that there is coupling between an external power supply and an on-vehicle charger, and a remaining amount in a low voltage battery is equal to or below a predetermined remaining amount, the charging controller causes the low voltage battery to be charged with electricity.

Inventors

• Tatsunori MAKINO
• Natsuki EHARA

Assignees

• HONDA MOTOR CO., LTD.

Dates

Publication Date

20260512

Application Date

20240219

Priority Date

20230331

Claims (7)

1. 1 . A power supply system for a vehicle, comprising: a low voltage circuit provided with a low voltage electric storage; a high voltage circuit provided with a high voltage electric storage that is higher in voltage than the low voltage electric storage; a charging circuit that couples the low voltage circuit and the high voltage circuit to each other; an on-vehicle charger that supplies, when coupled to an external power supply, direct current electric power to at least either of the high voltage circuit or the low voltage circuit; a coupling state detector that is able to detect that there is coupling between the external power supply and the on-vehicle charger; an operation receiver that receives an on operation or an off operation performed by a user for starting or stopping the vehicle; and a charging controller that causes the charging circuit to operate to execute auxiliary charging control for charging the low voltage electric storage with electricity, wherein, when a soak time representing a period of time elapsed after the off operation has been received is shorter than a first period of time that is determined beforehand, the coupling state detector has detected that there is coupling between the external power supply and the on-vehicle charger, and a remaining amount in the low voltage electric storage is equal to or below a predetermined remaining amount, the charging controller causes the low voltage electric storage to be charged with electricity, wherein the coupling state detector detects, based on mechanical coupling between a coupling terminal of the external power supply and the on-vehicle charger or based on an operation state at the coupling terminal of the external power supply, whether or not there is coupling between the external power supply and the on-vehicle charger, and wherein, when the soak time is shorter than the first period of time and the coupling state detector has detected that there is coupling between the external power supply and the on-vehicle charger, the charging controller causes the low voltage electric storage to be charged with electricity in such a manner that a charging speed for the low voltage electric storage is faster than a charging speed for the low voltage electric storage when the external power supply is not coupled to the on-vehicle charger.
2. 2 . The power supply system for the vehicle, according to claim 1 , wherein, when the soak time is shorter than the first period of time, the charging controller uses an amount of electric power equal to or below a value acquired by subtracting an amount of electric power for charging the high voltage electric storage with electricity from an amount of electric power supplied from the external power supply to charge the low voltage electric storage with electricity.
3. 3 . The power supply system for the vehicle, according to claim 1 , wherein, when the soak time is shorter than the first period of time, and the high voltage electric storage is undergoing charging with electricity, the charging controller does not cause the low voltage electric storage to be charged with electricity.
4. 4 . The power supply system for the vehicle, according to claim 1 , wherein, when the soak time is shorter than the first period of time, the low voltage electric storage is undergoing charging with electricity, and the coupling state detector detects that there is release of the coupling between the external power supply and the on-vehicle charger, the charging controller stops charging of the low voltage electric storage with electricity.
5. 5 . The power supply system for the vehicle, according to claim 1 , wherein, after charging of the high voltage electric storage with electricity is completed, the charging controller causes the on-vehicle charger to directly charge the low voltage electric storage with electricity.
6. 6 . The power supply system for the vehicle, according to claim 1 , wherein, after charging of the high voltage electric storage with electricity is completed, and the coupling state detector has detected that there is coupling between the external power supply and the on-vehicle charger, the charging controller causes the low voltage electric storage to be charged with electricity at a voltage for the low voltage electric storage higher than a charging voltage when the high voltage electric storage undergoes charging with electricity.
7. 7 . A control method performed in a power supply system for a vehicle, the control method comprising causing, when a soak time representing a period of time elapsed after an off operation performed by a user for stopping the vehicle has been received is shorter than a first period of time that is determined beforehand, a coupling state detector in the power supply system has detected that there is coupling between an external power supply and an on-vehicle charger, and a remaining amount in a low voltage electric storage is equal to or below a predetermined remaining amount, a charging controller in the power supply system to charge the low voltage electric storage with electricity, detecting, by a coupling state detector in the power supply system, based on mechanical coupling between a coupling terminal of the external power supply and the on-vehicle charger or based on an operation state at the coupling terminal of the external power supply, whether or not there is coupling between the external power supply and the on-vehicle charger, and when the soak time is shorter than the first period of time, and the coupling state detector has detected that there is coupling between the external power supply and the on-vehicle charger, causing, by the charging controller, the low voltage electric storage to be charged with electricity in such a manner that a charging speed for the low voltage electric storage is faster than a charging speed for the low voltage electric storage when the external power supply is not coupled to the on-vehicle charger.

Description

This application is based on and claims the benefit of priority from Chinese Patent Application No. 202310336311.4, filed on 31 Mar. 2023, the content of which is incorporated herein by reference. BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a power supply system for a vehicle and a control method for the power supply system. Related Art In recent years, research and development have been conducted on secondary batteries that contribute to energy efficiency in order to ensure that more people have access affordable, reliable, sustainable, and advanced energy. A power supply system mounted on an electric vehicle or a hybrid electric vehicle includes a high voltage battery storing electric power to be mainly supplied to a drive motor for traveling and a low voltage battery storing electric power to be mainly supplied to auxiliary devices at a voltage lower than a voltage at which the high voltage battery supplies electric power. For example, Patent Document 1 illustrates a power supply system for an electric vehicle, in which a high voltage circuit provided with a high voltage battery and a low voltage circuit provided with a low voltage battery are coupled to each other via a voltage converter. When charged electricity in the low voltage battery becomes insufficient in the power supply system illustrated in Patent Document 1, the voltage converter lowers a voltage of electric power that the high voltage battery supplies to charge the low voltage battery with electricity. Charging a low voltage battery using power supplied by a high voltage battery will also be hereinafter referred to as auxiliary charging. Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2021-151030 SUMMARY OF THE INVENTION Conventionally, there has been no auxiliary charging performed from a high voltage battery to a low voltage battery, regardless of a remaining amount in the low voltage battery, within a certain period of time after an off operation has been performed by a user for stopping a vehicle, from a viewpoint of maintainability for the vehicle in techniques regarding secondary batteries. Therefore, there has been a possibility that, within the certain period of time, the remaining amount in the low voltage battery lowers, making it impossible to start the vehicle. In view of solving the issues described above, an object of the present application is to achieve a power supply system for a vehicle and a control method for the power supply system that make it possible to securely start the vehicle even in a state where there is a higher possibility that a user does not perform preventive and predictive maintenance on the vehicle. This in turn contributes to energy efficiency. A power supply system for a vehicle, according to an aspect of the present disclosure includes: a low voltage circuit provided with a low voltage electric storage; a high voltage circuit provided with a high voltage electric storage that is higher in voltage than the low voltage electric storage; a charging circuit that couples the low voltage circuit and the high voltage circuit to each other; an on-vehicle charger that supplies, when coupled to an external power supply, direct current electric power to at least either of the high voltage circuit or the low voltage circuit; a coupling state detector that is able to detect that there is coupling between the external power supply and the on-vehicle charger; an operation receiver that receives an on operation or an off operation performed by a user for starting or stopping the vehicle; and a charging controller that causes the charging circuit to operate to execute auxiliary charging control for charging the low voltage electric storage with electricity, in which, when a soak time representing a period of time elapsed after the off operation has been received is shorter than a first period of time that is determined beforehand, the coupling state detector has detected that there is coupling between the external power supply and the on-vehicle charger, and a remaining amount in the low voltage electric storage is equal to or below a predetermined remaining amount, the charging controller causes the low voltage electric storage to be charged with electricity. Furthermore, the coupling state detector detects, based on mechanical coupling between a coupling terminal of the external power supply and the on-vehicle charger or based on an operation state at the coupling terminal of the external power supply, whether or not there is coupling between the external power supply and the on-vehicle charger. Furthermore, when the soak time is shorter than the first period of time, and the coupling state detector has detected that there is coupling between the external power supply and the on-vehicle charger, the charging controller causes the low voltage electric storage to be charged with electricity in such a manner that a charging speed for the low voltage ele