A method for detecting an insulation fault in a vehicle on-board electrical system having an HV on-board electrical system branch and an LV on-board electrical system branch provides for the LV on-board electrical system branch to have a positive supply potential and a negative supply potential that corresponds to a ground potential of the vehicle on-board electrical system. The HV on-board electrical system branch has a positive HV potential and a negative HV potential which are DC-isolated from the potentials of the LV on-board electrical system branch. An insulation fault between at least one of the HV potentials and a positive LV potential is detected by identifying a current flow through a voltage limiting circuit connected between the ground potential and the positive LV potential.

In a case where a load current flows in an energized state where a power supply is connected to a load, it is assumed that a measured voltage fluctuates due to a voltage drop caused by contact resistance of a relay contact, and thus the relay state cannot be accurately diagnosed. A relay control device that controls a relay connected between a secondary battery and a load device calculates, in a failure diagnosis during energization with the relay being closed, a contact resistance value of the relay based on a voltage applied to the relay and a current flowing through the secondary battery, and determines a first threshold set as a variable value in accordance with a temperature change amount of the relay and compares the calculated contact resistance value with the first threshold to diagnose a failure of the relay.

The invention relates to a method for connecting one or more electric battery units to an electrical system. The method comprises: maintaining a system short-circuit which short-circuits the electrical system; while the system short-circuit is maintained, electrically connecting a first electric battery unit, which is locally short-circuited by a local short-circuit, to the electrical system so as to include the first electric battery unit in the electrical system; and while the system short-circuit is maintained, removing the local short-circuit of the first electric battery unit, whereupon the first electric battery unit is short-circuited by the system short-circuit of the electrical system. The method may be performed as a part of an electrical system installation procedure in for example a hybrid or electric vehicle and allows the electric battery units to be connected to the electrical system in a safe way.

A vehicle and a method of immobilising a vehicle. The vehicle (100) includes a transport refrigeration unit (10), a power management system (20) for supplying power to the transport refrigeration unit (10), and a braking system (30). The power management system (20) includes an electric charging connector (26) and controller (24) configured to determine if a charging cable is engaged with the electric charging connector (26). If the controller (24) determines that a charging cable is engaged with the electric charging connector (26), the braking system (30) is configured to immobilise the vehicle (100).

A maintenance time acquisition unit acquires a periodic inspection and maintenance time determined in advance for each of a plurality of electric vehicles, a battery remaining life prediction unit predicts a remaining life of each of storage batteries from a state of the storage battery of each of the plurality of electric vehicles, and an operation plan creation unit creates an operation plan of the plurality of electric vehicles based on the periodic inspection and maintenance time of each of the plurality of electric vehicles and the remaining life of the storage battery of each of the plurality of electric vehicles.

An electric power conversion system and a vehicle, to improve vehicle availability. The electric power conversion system may receive electric energy provided by a first power supply, and supply power to at least one load module. The system may include a first direct current to direct current conversion module and a second direct current to direct current conversion module. The first direct current to direct current conversion module is configured to perform voltage conversion processing on the electric energy and provide the electric energy to the at least one load module. The second direct current to direct current conversion module is configured to perform voltage conversion processing on the electric energy and provide the electric energy to the at least one load module.

A method and a device test whether there is contact between a current collector and a contact wire of an overhead line. The current collector is located on a motor vehicle driven by an electric motor, and the contact wire extends in a direction of travel. The current collector has two contact regions oriented transversely to the direction of travel which are arranged one behind the other in the direction of travel and on each of which an end contact element is located. A pair of end contact elements located on the same side is connected to a measuring device and an electrical state variable is detected by the measuring device. Subsequently, it is determined in accordance with the detected state variable whether the pair of end contact elements is in contact with the overhead line.

A method and a device test whether there is contact between a current collector and a contact wire of an overhead line. The current collector is located on a motor vehicle driven by an electric motor, and the contact wire extends in a direction of travel. The current collector has two contact regions oriented transversely to the direction of travel which are arranged one behind the other in the direction of travel and on each of which an end contact element is located. A pair of end contact elements located on the same side is connected to a measuring device and an electrical state variable is detected by the measuring device. Subsequently, it is determined in accordance with the detected state variable whether the pair of end contact elements is in contact with the overhead line.

A power supply device is provided with a disconnection means (AND element) for forcibly disconnecting a battery module from a series connection regardless of a gate signal. The power supply device forcibly disconnects partial battery modules from the series connection by the disconnection means (AND element) during powering by a power supply output, thereby performing control so that the accumulated discharge current amounts thereof per unit time become smaller than those of the other battery modules.

A power supply device is provided with a disconnection means (AND element) for forcibly disconnecting a battery module from a series connection regardless of a gate signal. The power supply device forcibly disconnects partial battery modules from the series connection by the disconnection means (AND element) during powering by a power supply output, thereby performing control so that the accumulated discharge current amounts thereof per unit time become smaller than those of the other battery modules.