Space Systems/loral, LLC

Erik L Levine

John C Hall

Mitchell J Mehlman

Terry Weight

A method of charging a nickel-hydrogen battery which includes a positive electrode, a negative electrode and an electrolyte, after the battery has been subject to discharge is disclosed the method comprising the steps of: (a) subjecting the battery to a high charge rate for a period until the battery temperature increases at least &Dgr;T over the local minimum battery temperature; (b) switching the battery charge level to a lower rate of charge than in step (a) for a period until the battery temperature increases at least &Dgr;T over the local minimum battery temperature; (c) switching the battery charge level to a much lower rate of charge than step (b) for a period up to about 30 to 60 minutes before the next scheduled eclipse; and thereafter (d) switching the battery to a pulse charge equivalent to the high charge rate of step (a).

Battery temperature derivative charging

According to the present invention, a battery cell sleeve assembly includes a continuous tubular sleeve extending between proximal and distal ends and has a plurality of substantially unidirectional longitudinally extending elongated heat conduction fibers having a thermal conductivity no less than that of aluminum embedded in a suitable matrix. The sleeve is received on the outer peripheral surface of a tubular battery cell which is typically, but not necessarily cylindrical and in a contiguous relationship with the battery cell. A tubular base member having a peripheral flange is attached to the continuous tubular sleeve such that the distal ends of the heat conduction fibers are contiguous with the peripheral flange. With this construction, the peripheral flange operates as a heat shunt for drawing heat away from the continuous tubular sleeve by conduction between the heat conduction fibers and the peripheral flange. In one embodiment, the heat conduction fibers are graphite and the continuous tubular sleeve is between about 0.010 and 0.25 inches thick and composed of about 60% fiber and 40% adhesive by volume. An electrically insulative adhesive such as an epoxy with a defined bond line of about 0.005 inches is applied to the interface between the continuous tubular sleeve and the tubular base member. After integrating the battery cell and the continuous tubular sleeve, the battery cell is charged. This causes the battery cell to become pressurized which, in turn, enlarges its outer periphery such that it becomes more firmly engaged with the continuous tubular sleeve.

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San Jose, CA, United States of America

Erik L Levine