This device for actively discharging an electrical energy storage device has a branch having first and second ends connected respectively to positive and negative terminals of the electrical energy storage device, and between the two ends, a thermistor having a resistance that increases with a temperature of the thermistor and a switch designed to receive a control signal (v.sub.GS) to change from an open state to a closed state, the thermistor and the switch being connected to one another so that, when the switch is closed, a discharge current (i.sub.D) enters through the first end, flows through the thermistor (210) and the switch one after the other, and emerges through the second end; and a device for controlling the switch. The control device is connected to the switch so as to provide the control signal (v.sub.GS) independently of the resistance of the thermistor.

A method (100) for operating a vehicle (1) with an electric drive-train (2), wherein this electric drivetrain (2) is fed via a DC voltage source (3) and a converter (4) for converting the DC voltage into a single-phase or multiphase AC voltage, comprising the steps: —it is detected (110) that the vehicle (1) is stopped; — it is checked (120) on the basis of at least one specified criterion (10) whether the vehicle (1) is expected to be stopped only briefly; —in response to the fact that the vehicle (1) is expected to be stopped only briefly, the vehicle (1) is transferred (130) from the ready-to-drive state into a disabled state, wherein in this disabled state the vehicle (1) is protected against unauthorized use but the converter (4) continues to be supplied with the DC voltage from the DC voltage source (3); —in response to the fact that the vehicle (1) is not expected to be stopped only briefly, at least one functional test of the electric drivetrain (2), said test being provided for powering down the electric drivetrain (2), is performed (140), and after the termination of this functional test the vehicle (1) is transferred (150) into a switched-off state, in which the vehicle (1) is secured against unauthorized use and the supply of the converter (4) from the DC voltage source (3) is interrupted.

A method and to a device for ascertaining a state of health of a battery for a transportation device. The method includes: charging the battery until a predefined target voltage is reached in a first charging phase of the battery, ascertaining a first voltage value of the battery at a first predefined point in time after the predefined target voltage has been reached in a relaxation phase of the battery, ascertaining a second voltage value of the battery at a second predefined point in time, deviating from the first predefined point in time, in the relaxation phase of the battery, ascertaining a piece of information about the state of health of the battery based on a change of the second voltage value with respect to the first voltage value, and using the piece of information in the transportation device and/or in an external server.

A vehicle power supply device converts power from high voltage to low voltage by selectively connecting a predetermined power storage element group to a low voltage electric load from a high voltage power supply formed by connecting power storage elements in series. A leakage current from the high voltage power supply is measured during the dead time period when the power storage element group is not connected to the low voltage electric load. When the value exceeds a predetermined value, the connection between the power storage element group and the low-voltage electric load is interrupted, so that electric shock is prevented.

A battery pack for efficiently supplying a power to a vehicle and including a battery assembly, a power supply terminal connectable to a connection terminal of the vehicle that is connected to a vehicle control unit and a vehicle motor, a power supply path located between the power supply terminal and the battery cell and supplying a power from the battery cell to the power supply terminal, a switching unit provided on the power supply path electrically turn on/off the power supply path, a mounting recognition unit recognizing whether the battery pack is mounted to the vehicle, and a processor controlling the switching unit so that a power is supplied from the battery cell to the vehicle control unit, when receiving a signal from the mounting recognition unit that the battery pack is recognized as being mounted to the vehicle.

A battery system includes a battery module, a housing, a gas conveyor, and a gas sensor. The battery module is interconnected between a first system terminal and a second system terminal by a plurality of high current connectors, and the housing includes: a plurality of exterior walls enclosing the battery module and the plurality of high current connectors; and a partition wall within the housing. The gas conveyor is configured to circulate a gas flow through a flow channel loop formed within the housing by the partition wall and the exterior walls, and the gas sensor is arranged in the flow channel loop and is configured to detect an excess concentration of a gas species in the gas flow.

A ground impedance and fault detection system may include a controller that can identify a location of a ground fault in a circuit. The circuit also may include one or more positive contactors connected with a positive portion of the bus between battery strings and a load and a negative bus contactor coupled with a negative portion of the bus between the battery strings and the loads. The controller may identify the ground fault by opening the one or more positive contactors and closing the negative bus contactor, measuring the voltages using the impedance devices, and comparing the voltages that are measured.

A utility cart includes a stored energy device that can be in the form of a Lithium Ion battery pack. The battery pack can include a main power output useful to drive high voltage components as well as the electric motor for motive power. The battery pack can also include one or more auxiliary outputs useful to provide auxiliary power to various other components. The auxiliary outputs can be either low and/or high voltage outputs. An auxiliary DC/DC output can be used to step down high voltage of the Lithium ion battery pack to lower voltages. A motor controller supply can also be provided as an auxiliary output to provide some power to a motor controller.

A battery pack enclosure, a battery module, and a method are provided to detect damage to in a crash event. The battery pack enclosure may include a plurality of battery modules, wherein each battery modules includes a plurality of adjacent battery cells. The battery pack enclosure may also include a sensor and an electronic control unit electronically connected to the sensor, the electronic control unit configured to monitor the sensor to detect damage to the battery pack enclosure. The sensor may comprise a mesh of resistive wires, and the electronic control unit monitors the overall resistance of the mesh resistive wires. The overall resistance of the mesh resistive wires can be used to determine whether there is damage to the battery pack enclosure. If damage is detected, the damage can further be located, and an alert sent.

Systems and methods for identifying thermal run-away events in a battery pack can include using sensing circuits made up of series- or parallel-linked thermistors to measure subsets of the individual battery cells in a battery pack. Using multiple sensing circuits, a monitoring system can positively identify when a threshold temperature of any single battery cell has been reached even though individual temperatures are not monitored, and can generate a signal indicative of a thermal run-away event based on the detected temperature.