Rotor hubs described herein include a frustoconical body having a base, a frustum, and a longitudinal axis extending therebetween, and a plurality of elongated protrusions spaced about a circumference of the base and extending from the base parallel to the longitudinal axis.

An example flywheel energy storage device includes a continuously curved fiber-resin composite ovoid shell. Hubs are concentrically disposed within and outside the shell at the shaft. A plurality of radially oriented, fiber-resin composite helical wraps of uniform width are used to construct the ovoid shell and couple the shell to the hubs for co-rotation and torque transfer. Integrated internal structures are attached to the external ovoid shell and provide compression support for the external ovoid shell. Upon rotation, the ovoid shell elongates slightly to increase the flywheel effective moment of inertia at operational speeds.

Apparatuses, systems and methods are described for a flywheel system incorporating a rotor made from a high-strength material in an open-core flywheel architecture with a high-temperature superconductive (HTS) bearing technology to achieve the desired high energy density in the flywheel energy storage devices, to obtain superior results and performance, and that eliminates the material growth-matching problem and obviates radial growth and bending mode issues that otherwise occur at various high frequencies and speeds.

Apparatuses, systems and methods are described for a flywheel system incorporating a rotor made from a high-strength material in an open-core flywheel architecture with a high-temperature superconductive (HTS) bearing technology to achieve the desired high energy density in the flywheel energy storage devices, to obtain superior results and performance, and that eliminates the material growth-matching problem and obviates radial growth and bending mode issues that otherwise occur at various high frequencies and speeds.

A flywheel formed of a composite material having fibers, oriented substantially in a circumferential direction around the flywheel, embedded in a matrix material. The flywheel having an inner surface, an outer surface, and a thickness therebetween and defining an axis of rotation. A plurality of load masses are distributed circumferentially on the inner surface at a longitudinal segment along the axis. A rotation of the flywheel about the axis with a rotational velocity generating hoop stress in the fibers in the circumferential direction and through-thickness stress is generated in the matrix material in a radial direction. Each load mass produces a force on the inner surface operative to reduce the maximum through-thickness stress in the matrix material as the flywheel rotates about the axis. The rotational velocity otherwise sufficient to produce structural failure of the matrix material produces structural failure of the fibers and not the matrix material.

A flywheel formed of a composite material having fibers, oriented substantially in a circumferential direction around the flywheel, embedded in a matrix material. The flywheel having an inner surface, an outer surface, and a thickness therebetween and defining an axis of rotation. A plurality of load masses are distributed circumferentially on the inner surface at a longitudinal segment along the axis. A rotation of the flywheel about the axis with a rotational velocity generating hoop stress in the fibers in the circumferential direction and through-thickness stress is generated in the matrix material in a radial direction. Each load mass produces a force on the inner surface operative to reduce the maximum through-thickness stress in the matrix material as the flywheel rotates about the axis. The rotational velocity otherwise sufficient to produce structural failure of the matrix material produces structural failure of the fibers and not the matrix material.

A dome connector for a flywheel rim to shaft attachment is provided. The dome connector includes a helically wound composite band that extends from a first port to a second port. The helically wound composite band has a helical angle in relation to a line perpendicular to a center of axis of the dome connector. The helical angle is selected to at least in part achieve a desired stiffness in the dome connector.

A dome connector for a flywheel rim to shaft attachment is provided. The dome connector includes a helically wound composite band that extends from a first port to a second port. The helically wound composite band has a helical angle in relation to a line perpendicular to a center of axis of the dome connector. The helical angle is selected to at least in part achieve a desired stiffness in the dome connector.

A rotational body, to a rotor and to a flywheel energy storage unit having such rotational bodies is disclosed and a method for the production of a rotational body, having a cylinder jacket at least partially wound using a fiber-reinforced composite. A cylinder axis includes open cylinder base surfaces, whereby the cylinder jacket, with its inside facing the axis of rotation and its outside oriented in the opposite direction, has a length parallel to the axis of rotation of more than twice the outer diameter of the rotational body, and it has a wall thickness that is less than 12.5% of the outer diameter. The fiber-reinforced composite of the cylinder jacket has a layered structure in the radial direction comprising helical layers of fibers which extend along the axis of rotation and whose orientation along the helical fiber angle is less than 35 relative to the axis of rotation.

A rotational body, to a rotor and to a flywheel energy storage unit having such rotational bodies is disclosed and a method for the production of a rotational body, having a cylinder jacket at least partially wound using a fiber-reinforced composite. A cylinder axis includes open cylinder base surfaces, whereby the cylinder jacket, with its inside facing the axis of rotation and its outside oriented in the opposite direction, has a length parallel to the axis of rotation of more than twice the outer diameter of the rotational body, and it has a wall thickness that is less than 12.5% of the outer diameter. The fiber-reinforced composite of the cylinder jacket has a layered structure in the radial direction comprising helical layers of fibers which extend along the axis of rotation and whose orientation along the helical fiber angle is less than 35 relative to the axis of rotation.