A solar cell array has groups of solar cells (hereinafter called “cell string”) in which a plurality of solar cells are connected in series, bypass diodes (hereinafter called “CST bypass diode”) that are connected to each of the groups in parallel, and reverse-current preventive diodes that are connected to one or more cell strings in series.
FIG. 1 is an illustration of the circuit of a solar cell array. A solar cell array 91 contains a cell string 92a in which a plurality of cells (95a1, 95a2, and 95an) are connected in series and a cell string 92b in which a plurality of cells (95b1, 95b2, and 95bn) are connected in series in the same way. CST bypass diodes 93a and 93b are connected to the cell strings 92a and 93b in parallel, respectively. In addition, CST bypass diodes 93c and 93d are connected to other cell strings 92c and 92d in parallel, respectively. A reverse-current preventive diode 94p is connected to the cell strings 92a and 92b in series. A reverse-current preventive diode 94q is connected to the cell strings 92c and 92d in series in the same way. Bypass diodes for a single cell (96a1, 96a2, 96an, 96b1, 96b2, and 96bn) are placed to protect each cell from reverse current. Said bypass diodes for a single cell may be omitted.
In conventional approaches, there have been proposed solar cell modules in which a CST bypass diode, together with a plurality of solar cells, is integrally sealed between the front surface member and the rear surface member of the modules. The CST bypass diode for the proposed solar cell modules comprise a bear chip diode, an attaching section having conductive members arranged on each side of the bear chip diode (such conductive members constitute a mounting surface), and a base unit made from materials with excellent heat dissipativity, which base unit is arranged together with the attaching section outside the bear chip diode (refer to the patent document 1, for example).
Furthermore, a diode in which the upper surface and the under surface of the diode with lead terminals connected are arranged almost on the same plane has been proposed as a bypass diode for a single solar cell (refer to the patent document 2, for example).                Patent document 1: Japanese Patent Laid-Open No. 2000-164910 bulletin        Patent document 2: Japanese Patent Laid-Open No. 2000-277785 bulletin