A power supply apparatus includes a first battery, a second battery, and an ECU configured to determine whether the following conditions i), ii), and iii) are satisfied: i) a degree of deterioration of the second battery is lower than a first threshold; ii) a state-of-charge of the second battery is lower than a second threshold; and iii) the state-of-charge is equal to or higher than a third threshold. The second threshold is higher by a prescribed value than a lowest allowable value of the state-of-charge at which the second battery can function as a backup power supply. The third threshold corresponds to the lowest allowable value. When determining that the conditions i), ii) and iii) are all satisfied, the ECU executes single-battery-using control in which regeneration control using the regenerative electric power is executed with use of the first battery and the second battery is not used for regeneration control.

According to one embodiment, an electricity storage control device includes a setting unit, and a control unit. The setting unit sets, for each time zone, a target state of charge (SOC) of electric energy to be stored in an electricity storage device in the time zone. The control unit controls at least charging or discharging of the electricity storage device based on the set target SOC for each time zone, a SOC detected from the electricity storage device, and a voltage of a supply destination of electric power from the electricity storage device.

A motor vehicle energy storage device includes a first electrical energy store characterized by a first characteristic voltage curve defining the open-circuit voltage of the first energy store depending on the relative charge state and by a first characteristic resistance curve defining the internal resistance of the first energy store relevant for a charge process of the energy store, and a second electrical energy store connected in parallel and characterized by a second characteristic voltage curve defining the open-circuit voltage of the second energy store depending on the relative charge state and by a second characteristic resistance curve defining the internal resistance relevant for a charge process of the second energy store. The voltage value ranges covered by the first characteristic voltage curve and the second characteristic voltage curve partially overlap, and the first and second characteristic resistance curves and the second characteristic resistance curve have exactly one intersecting point.

A vehicle power supply apparatus includes first and second power supply systems, an electrical conduction path, a switch, and a switch controller. The first power supply system includes a first electrical energy accumulator and an electric load. The second power supply system includes a generator and a second electrical energy accumulator. The switch is configured to be controlled to a turn-on state and a turn-off state. The turn-on state includes coupling the electric load and the second electrical energy accumulator to each other, and the turn-off state includes isolating them from each other. The switch controller controls the switch to the turn-on state on the condition that the generator has an abnormality, and afterwards controls the switch to the turn-off state.

A power system for a vehicle comprises a first power supply network configured to operate at a first voltage. The first power supply network comprises a first alternator, a starter motor, and a battery conductively connected to the first alternator and the starter motor. The system further comprises a second power supply network configured to operate at a second voltage. The second power supply network comprises a second alternator, a power supply receptacle configured to output power to an external accessory, and a capacitive energy storage device conductively connected to the second alternator and the power supply receptacle. A directional conduction device interconnects the first power supply network and the second power supply network.

The invention relates to a vehicle electrical system that includes a first energy accumulator which has a first maximum open circuit voltage when the first energy accumulator is fully charged, and a second energy accumulator which has a second maximum open-circuit voltage when the second energy accumulator is fully charged. The second maximum open circuit voltage is higher than the first maximum open circuit voltage. The vehicle electrical system also includes a generator configured to generate electrical energy for the vehicle electrical system and a control unit that is configured to detect a recuperation mode of the vehicle. The control unit is also configured to cause the generator, while the vehicle is in the recuperation mode, to generate electrical energy with a charge voltage which is in or above a buffer voltage range, wherein the buffer voltage range lies between the first maximum open circuit voltage and the second maximum open circuit voltage.

An electric power supply system for a vehicle includes a first battery, a second battery connected in parallel with the first battery, a voltage sensor configured to detect a voltage value of the second battery, a current sensor configured to detect a current value of the second battery, an electronic control unit configured to make a voltage of the alternator fluctuate according to a predetermined voltage waveform, and calculate internal resistance of the second battery using the voltage value and the current value of the second battery respectively detected by the voltage sensor and the current sensor while the electronic control unit is making the voltage of the alternator fluctuate according to the predetermined voltage waveform.

An electric power supply device includes a first battery electrically connected to each of a plurality of load instruments mounted on a vehicle and supplying electric power to each of the load instruments, a second battery electrically connected to the first battery and each of the load instruments via a switch and capable of supplying electric power to each of the load instruments, and an electronic control unit (ECU) configured to cut off electrical connection between the second battery and each of the load instruments by turning OFF the switch under a condition that when a high-load instrument included in the load instruments is not in operation.

Systems and methods for improving operation of a hybrid vehicle are presented. In one example, an engine may be started in one of two ways depending on operating conditions. In particular, the engine may be started via a lower power output electric machine or a higher power output electric machine.

A method for operating an energy supply unit for a motor vehicle electrical system, including at least one first subsystem and one second subsystem having different voltage levels, the energy supply unit including an electric machine which is connected via a converter circuit to the first subsystem and the second subsystem. In a first operating mode, a switchable switch element of the converter circuit which connects the converter circuit to the second subsystem is opened, the converter circuit is activated as an inverter circuit and the electric machine is motor or generator operated. In a second operating mode, the switchable switch element of the converter circuit is closed, the converter circuit is activated as a DC-DC converter and the DC-DC conversion takes place between the voltage levels of the first and the second subsystem.