Abstract: Techniques to control flight of an aircraft are disclosed. In various embodiments, a set of inputs associated with a requested set of forces and moments to be applied to the aircraft is received. An optimal mix of actuators and associated actuator parameters to achieve to an extent practical the requested forces and moments is determined.

Abstract: A power distribution circuit for an electrically powered aircraft includes a plurality of batteries and a plurality of electric propulsion systems. A plurality of power distribution circuits each couple a battery of the plurality of batteries to two or more electric propulsion systems. The plurality of electric propulsion systems are positioned on the aircraft to apply balanced forces to the aircraft such that in the event of a failure, the aircraft remains stable and only experiences a loss in altitude or speed.

Abstract: Embodiments provide a propeller ground stop mechanism configured to keep an unpowered propeller of an aircraft (e.g. when the aircraft is on the ground and not operating) static. The propeller is prevented from rotating due to external forces (e.g. an air flow caused by wind, manual rotation of the propeller). When the propeller is powered, and the propeller is providing thrust, the propeller ground stop mechanism automatically disengages and does not provide any drag. Among various benefits, the propeller ground stop mechanism provides added safety to the ground support personnel.

Abstract: One or more battery sub-modules are selected by obtaining at least one voltage from each battery sub-module and selecting based at least in part on the obtained voltages. The battery sub-modules are electrically connected in series in order to provide power to a primary load. Each battery sub-module includes a plurality of cells electrically connected in series and each battery sub-module further includes a battery management system that monitors the cells in that battery sub-module. Those battery management systems in the selected sub-modules are turned off so that the battery management systems in the selected sub-modules do not consume power at least temporarily from the cells in the selected sub-modules while (1) the battery sub-modules are not providing power to the primary load and (2) the battery sub-modules are not being charged.

Abstract: An electrically powered vehicle includes a plurality of batteries and a plurality of DC to DC converters, each coupled to a respective battery of the plurality of batteries. Each DC to DC converter transfers power from a respective battery to a common DC bus. The common DC bus is coupled to a plurality of inverter circuits that convert the DC power to AC power. A plurality of electric motors receive power from the plurality of inverter circuits to propel the vehicle. During a regenerative event, the DC to DC converters can transfer power from the motors back to the batteries. In response to the failure of a battery, the DC to DC converters can isolate the remainder of the system from the failure.

Abstract: Techniques to control flight of an aircraft are disclosed. In various embodiments, a set of inputs associated with a requested set of forces and moments to be applied to the aircraft is received. An optimal mix of actuators and associated actuator parameters to achieve to an extent practical the requested forces and moments is determined.

Abstract: For each cell in a plurality of cells from a same manufacturing run, a first and a second cell characteristic are received in order to obtain a plurality of cell characteristics. For each cell, a batch compatibility number that is associated with a number of compatible cells that that cell is compatible with is determined based at least in part on the plurality of cell characteristics. The plurality of cells is sorted according to the batch compatibility numbers to obtain a sorted list of cells. A plurality of compatible cells to include in a battery is selected from the plurality of cells, including by evaluating the plurality of cells according to the order of the sorted list of cells and beginning with the lowest batch compatibility number.

Abstract: The embodiments describe a system and the corresponding assembly techniques of a battery submodule top cover. The battery submodule top cover has at least one electrical hybrid interconnect coupled to a substrate. The hybrid interconnect comprises at least a first portion made of a first metal type, and a second portion made of a second metal type. The first portion and the second portion of the hybrid interconnect are joined together such that an electrical connection may be made between two battery cell tabs where each battery cell tab is made of a different type of metal.

Abstract: Various embodiments of a technique to estimate and monitor a self-discharge rate for use as a measure of battery health are described herein. In some embodiments, the technique includes a system including a processor and a memory coupled with the processor. The memory is configured to provide the processor with instructions that when executed cause the processor to receive a plurality of snapshots obtained by monitoring a battery system in a quiescent state at a plurality of times. Each snapshot includes a plurality of cell state values at one of the plurality of times. The memory is further configured to provide the processor with instructions that when executed cause the processor to estimate a self-discharge indicator using at least one snapshot in the plurality of snapshots, compare the self-discharge indicator to a threshold, and recommend a remedy for the battery system in response to the self-discharge indicator exceeding the threshold.

Abstract: Embodiments provide a VTOL aircraft including a plurality of tilting propeller assemblies each coupled to a support structure and configured to transition between a vertical flight and a forward flight position. Each tilting propeller assembly comprising a propeller and a movable fairing provided downstream of the propeller. The movable fairing is configured to extend along an axis of rotation of the propeller. When the tilting propeller assembly transitions between the vertical and forward flight position, the movable fairing is configured to swivel to extend parallel to the direction of resultant airflow over the tilting propeller assembly into a minimum drag orientation. The movable fairing is damped enough to prevent any oscillations from the propeller wake shedding, and at the same time, keep the propeller aligned in a minimum-drag orientation with the resultant flow.

Abstract: A first portion of a series battery is arranged where the first portion of the series battery produces a first magnetic field and the series battery includes a plurality of charge storage devices, a negative output terminal, a positive output terminal, and a plurality of intradevice connections connecting the plurality of charge storage devices in series. A second portion of the series battery is arranged such that a second magnetic field produced by the second portion of the series battery at least partially cancels out the first magnetic field.

Abstract: A power delivery system includes a controller, configured to receive a voltage indication signal indicating a measured voltage of a battery management system and to determine whether first and second diodes of the battery management system are faulty based on the voltage indication signal. The controller is also configured to respectively receive first and second current indication signals from first and second current sensors of the battery management system and to determine whether the first and second diodes of the first battery management system are faulty based on the first and second current indication signals.

Abstract: A first portion of a series battery is arranged where the first portion of the series battery produces a first magnetic field and the series battery includes a plurality of charge storage devices, a negative output terminal, a positive output terminal, and a plurality of intradevice connections connecting the plurality of charge storage devices in series. A second portion of the series battery is arranged such that a second magnetic field produced by the second portion of the series battery at least partially cancels out the first magnetic field.

Abstract: Battery management systems and methods can provide real-time automated monitoring of various aspects of battery health and operation. Some battery management systems can use an equivalent cell circuit model to predict a range for the expected behavior of a battery cell under actual operating conditions in real-time. The prediction can be compared to the actual behavior of the cell to determine whether an anomaly exists. Some battery management systems can maintain an estimate of battery state-of-health parameters such as charge capacity and internal resistance and can update these estimates in real time while the battery is being discharged and/or charged. Anomalous variations in a monitored parameter can trigger a real-time fault notification.

Abstract: A battery system includes a can with a lip around an opening. At least an interior surface of the can is anodized and the lip of the can includes a longer and shorter side. The can further includes a flange on the longer side of the lip and a plurality of layers that are inserted into the can. The plurality of layers includes a battery cell and a thermally conducting layer with a fin and the fin has a spring force that pushes the fin towards the anodized interior surface. The battery system further includes a lid that is configured to cover the opening of the can, where the flange is configured to wrap around the lid when the lid covers the opening of the can.

Abstract: A composite airfoil is disclosed. In various embodiments, a composite airfoil as disclosed herein includes an outer skin comprising one or more layers of carbon fiber composite material, the outer skin defining an aerodynamic surface having a leading edge; and a reinforcement material comprising a roll of fiberglass reinforced fabric positioned behind the outer skin along at least a portion of the leading edge.

Abstract: A solid electrolyte interface is formed on a silicon monoxide electrode in a battery cell. While the solid electrolyte interface is being formed on the silicon monoxide electrode, the battery cell is charged for one or more initial cycles.

Abstract: Battery management systems and methods can provide real-time automated monitoring of various aspects of battery health and operation. Some battery management systems can use an equivalent cell circuit model to predict a range for the expected behavior of a battery cell under actual operating conditions in real-time. The prediction can be compared to the actual behavior of the cell to determine whether an anomaly exists. Some battery management systems can maintain an estimate of battery state-of-health parameters such as charge capacity and internal resistance and can update these estimates in real time while the battery is being discharged and/or charged. Anomalous variations in a monitored parameter can trigger a real-time fault notification.

Abstract: For each cell in a plurality of cells from a same manufacturing run, a first and a second cell characteristic are received in order to obtain a plurality of cell characteristics. For each cell, a batch compatibility number that is associated with a number of compatible cells that that cell is compatible with is determined based at least in part on the plurality of cell characteristics. The plurality of cells is sorted according to the batch compatibility numbers to obtain a sorted list of cells. A plurality of compatible cells to include in a battery is selected from the plurality of cells, including by evaluating the plurality of cells according to the order of the sorted list of cells and beginning with the lowest batch compatibility number.

Abstract: In various embodiments, a tilt-wing aircraft includes a fuselage; a first wing tiltably mounted at or near a forward end of the fuselage; and a second wing rotatably mounted to the fuselage at a position aft of the first wing. A first plurality of rotors is mounted on the first wing at locations on or near a leading edge of the first wing, with two or more rotors being mounted on wing portions on each side of the fuselage; and a second plurality of rotors mounted on the second wing at locations on or near a leading edge of the second wing, with two or more rotors being mounted on wing portions on each side of the fuselage. A flight control system generates a set of actuators and associated actuator parameters to achieve desired forces and moments.