Abstract: A battery includes a housing, a positive pole, a negative pole, and a plurality of rechargeable electrochemical energy storage elements arranged in the housing. Each respective rechargeable electrochemical energy storage element is connected to a common circuit board and/or arranged in or on a common cell holder frame. A first subset of 24 to 42 rechargeable electrochemical energy storage elements of the plurality of rechargeable energy storage elements is connected in series and/or in parallel to form a primary pack. A second subset of 4 to 12 rechargeable electrochemical energy storage elements of the plurality of rechargeable energy storage elements is connected in series and/or in parallel to form a secondary pack. The primary pack has a positive output electrically connected to the positive terminal of the battery and a negative output electrically connected to the negative terminal of the battery. Battery management electronics can additionally be provided.

Abstract: An electric machine includes at least one stator having at least one individual-tooth winding carrier that has at least one spacer configured to space apart turns of an individual-tooth winding mounted on the individual-tooth winding carrier. A hybrid electric aircraft has an electric machine of this kind.

Abstract: An electric machine includes at least one stator having at least one individual-tooth winding carrier that has at least one spacer configured to space apart turns of an individual-tooth winding mounted on the individual-tooth winding carrier. A hybrid electric aircraft has an electric machine of this kind.

Abstract: An electric machine includes at least one stator having at least one individual-tooth winding carrier that has at least one spacer configured to space apart turns of an individual-tooth winding mounted on the individual-tooth winding carrier. A hybrid electric aircraft has an electric machine of this kind.

Abstract: An electric machine includes at least one stator having at least one individual-tooth winding carrier that has at least one spacer configured to space apart turns of an individual-tooth winding mounted on the individual-tooth winding carrier. A hybrid electric aircraft has an electric machine of this kind.

Abstract: A method includes: assembling first and second pieces in a slip-fit joint without applying adhesive or sealant, wherein the first piece covers a portion of the second piece in the slip-fit joint; and injecting adhesive through the first piece until the adhesive fills a gap of the slip-fit joint, wherein the adhesive makes the slip-fit joint air tight without applying the sealant. An air-tight slip-fit joint consists essentially of: first and second pieces assembled without applying adhesive or sealant, wherein the first piece covers a portion of the second piece in the slip-fit joint; and adhesive injected through the first piece until the adhesive fills a gap of the slip-fit joint, wherein the adhesive makes the slip-fit joint air tight without applying the sealant.

Abstract: A controller identifies a condition of a hazardous internal short by comparing patterns of series element voltages to the last known balance condition of the series elements. If the loaded or resting voltage of one or more contiguous series elements uniformly drop from the previously known condition by an amount consistent with an over-current condition, an over-current internal short circuit fault is registered. The desired response is to prevent the affected series elements from heating to a hazardous temperature by summoning the maximum heat rejection capability of the system until the short ceases and the affected elements cool, the cooling function is no longer able to operate due to low voltage, or the affected series string has drained all of its energy through the short. Also includes are responses that allow the battery pack to continue to power the cooling system even though it may enter an over-discharged state.

Abstract: A controller identifies a condition of a hazardous internal short by comparing patterns of series element voltages to the last known balance condition of the series elements. If the loaded or resting voltage of one or more contiguous series elements uniformly drop from the previously known condition by an amount consistent with an over-current condition, an over-current internal short circuit fault is registered. The desired response is to prevent the affected series elements from heating to a hazardous temperature by summoning the maximum heat rejection capability of the system until the short ceases and the affected elements cool, the cooling function is no longer able to operate due to low voltage, or the affected series string has drained all of its energy through the short. Also includes are responses that allow the battery pack to continue to power the cooling system even though it may enter an over-discharged state.