Abstract: A system and method for discharging a high voltage vehicle battery. The system includes a discharge circuit having a reference voltage source providing a reference voltage and a load for discharging the battery. A negative terminal of the voltage source is electrically coupled to a negative terminal of the battery so that upon initiation of the discharging sequence, the battery is discharged through the load to the reference voltage. The discharge circuit can be electrically configured so that the battery, the voltage source and the load are electrically coupled in series or the battery, the voltage source and the load are electrically coupled in parallel.

Abstract: A sensor for detecting leaked cooling fluid in a battery pack or container. The sensor is part of a sensor wire, where one end of the wire is electrically coupled to the positive terminal or the negative terminal of the battery pack and the other end of the wire is positioned at a location where the leaked cooling fluid may accumulate. A fault isolation detection circuit monitors a voltage output from the sensor and determines that there is a cooling fluid leak if the measured voltage potential is greater than a predetermined voltage threshold.

Abstract: A device and method for operating automotive battery system relays and related switches. By aligning a magnetic field with a direction of current flow in a contact plate disposed between magnets that are producing the field, a generated Lorentz force can be used to promote arc extinguishing during a relay opening sequence, while simultaneously reducing the tendency of the Lorentz forces to interfere with the operation of a solenoid or other switch-activating mechanisms. By using a rotary-based mechanism to establish contact between a contact plate and current-carrying terminals, the likelihood of inadvertent opening of the relay is reduced. Such devices and methods may be used in conjunction with hybrid-powered and electric-powered vehicles.

Abstract: A system and method for determining whether a resistor in a battery circuit on an electric vehicle cannot be used as a resistive heater for heating a cooling fluid for cooling the vehicle battery, but can used as a pre-charge resistor for starting the vehicle. A temperature sensor is provided proximate the resistor within the cooling fluid. The method turns on the resistor before turning on a coolant pump and samples the temperature at sample intervals over a predetermined period of time. The method then calculates an integral or differential of the sampled temperatures and compares that value with a calibrated threshold. If the temperature value is not greater than the threshold, meaning that the temperature indicates no cooling fluid is present, the algorithm disables the resistor for heating purposes, but maintains operation of the resistor for pre-charge purposes.

Abstract: A device and method for operating automotive battery system relays and related switches. By aligning a magnetic field with a direction of current flow in a contact plate disposed between magnets that are producing the field, a generated Lorentz force can be used to promote arc extinguishing during a relay opening sequence, while simultaneously reducing the tendency of the Lorentz forces to interfere with the operation of a solenoid or other switch-activating mechanisms. By using a rotary-based mechanism to establish contact between a contact plate and current-carrying terminals, the likelihood of inadvertent opening of the relay is reduced. Such devices and methods may be used in conjunction with hybrid-powered and electric-powered vehicles.

Abstract: A method and system for power management among batteries of varying states of health. Two or more battery packs are switched on and off in square wave pulses to energize a multi-winding transformer, and the output of the transformer is used to power a load. As the state of charge of the battery packs decrease at different rates, the duty cycle of each battery pack's switch pulse is made proportional to its state of charge relative to the other battery packs. The battery pack with the greatest state of charge has the longest on-time and provides the most energy to the transformer, yet all battery packs contribute. A baseline duty cycle is computed by a proportional integral control module, based on voltage measurements at the load. Energy contribution is managed so that state of charge does not diverge even when the battery packs have widely varying states of health.

Abstract: A device and method for operating automotive battery system relays and related switches. By creating a dual bipolar magnetic field adjacent the contactor portion of a switching mechanism in the relay, the magnetic field used to promote arc extinguishing is shifted, which in turn reduces the Lorentz force that forms as a byproduct of the field. Such a configuration has the potential for simultaneously maintaining arc-extinguishing capability and improving short-circuit withstanding capability while reducing the tendency of the Lorentz forces to interfere with the operation of a solenoid or other switch-activating mechanisms. Such devices and methods may be used in conjunction with hybrid-powered and electric-powered vehicles.

Abstract: A device and method for operating automotive battery system relays and related switches. By aligning a magnetic field with a direction of current flow in a contact plate disposed between magnets that are producing the field, a generated Lorentz force can be used to promote arc extinguishing during a relay opening sequence, while simultaneously reducing the tendency of the Lorentz forces to interfere with the operation of a solenoid or other switch-activating mechanisms. By using a rotary-based mechanism to establish contact between a contact plate and current-carrying terminals, the likelihood of inadvertent opening of the relay is reduced. Such devices and methods may be used in conjunction with hybrid-powered and electric-powered vehicles.

Abstract: A system and method for use with a vehicle battery pack having a number of individual battery cells, such as a lithium-ion battery commonly used in hybrid electric vehicles. In one embodiment, the method evaluates individual battery cells within a vehicle battery pack in order to obtain accurate estimates regarding their average transient voltage effect, open circuit voltage (OCVCell) and/or state of charge (SOCCell) so that a cell balancing process can be performed. These cell evaluations may be performed fairly soon after the vehicle is turned off and in a manner that utilizes a minimal amount of in-vehicle resources.

Abstract: A circuit that detects if contacts in an HV contactor have been welded or stuck closed. The circuit includes a controller that generates a short duration pulse signal that closes a driver switch and allows current flow through a coil in the HV contactor. The current flow is converted to a voltage by a sensor, where the voltage is received by the controller. The controller uses the voltage, such as by comparing the voltage to a stored representative voltage of the coil current for when the HV contactor is open, to determine whether the HV contactor is closed, and possibly welded or stuck closed, or partially closed. The sensor can be the driver switch or another device, such as a resistor.

Abstract: A system and method for use with a vehicle battery pack having a number of individual battery cells, such as a lithium-ion battery commonly used in hybrid electric vehicles. In one embodiment, the method evaluates individual battery cells within a vehicle battery pack in order to obtain accurate estimates regarding their average transient voltage effect, open circuit voltage (OCVCell) and/or state of charge (SOCCell) so that a cell balancing process can be performed. These cell evaluations may be performed fairly soon after the vehicle is turned off and in a manner that utilizes a minimal amount of in-vehicle resources.