Abstract: A control device and a control method for equally charging and discharging battery units may prolong life of the battery units of the control device. The control method includes steps of: detecting the battery units to generate measuring parameters; calculating determining parameters; calculating an average value of the determining parameters; selecting one of the battery units according to an operating status of the battery units; calculating a setting parameter; setting a pause time; charging or discharging the selected battery unit after stopping charging or discharging the selected battery unit for the pause time. When the battery units are charged or discharged, an overcharged or over-discharged battery unit may be selected. The selected battery unit may be stopped charging or discharging for the pause time. Therefore, life of the battery units may be prolonged.

Abstract: A battery parallel device having a charge path and a discharge path with equal impedances includes at least one first parallel apparatus. The at least one first parallel apparatus has first battery units each having a plurality of first batteries, a first positive connector electrically connected to positive electrodes of the first batteries, a first negative connector electrically connected to negative electrodes of the first batteries, a first positive electrode connector formed on the first positive connector, a first negative electrode connector formed on the first negative connector, first current paths formed between the first positive electrode connector and the positive electrodes, and second current paths formed between the first negative electrode connector and the negative electrodes. A total path length of the first current paths and a total path length of the second current paths corresponding to the same first batteries are equal. Therefore, inrush current may be decreased.

Abstract: A weldingless cylindrical battery pack device has a first lid body, a second lid body, multiple cylindrical batteries, multiple screwing elements, a first elastic piece, and a second elastic piece. The cylindrical batteries are mounted between the first lid body and the second lid body. The first lid body and the second lid body are screwed together by the screwing elements. Further, the first elastic piece is electronically connected to positive electrodes of the cylindrical batteries, and the second elastic piece is electronically connected to negative electrodes of the cylindrical batteries. The cylindrical batteries do not need to be welded, and the weldingless cylindrical battery pack device may be easily and quickly manufactured.