50 likes | 194 Views
Variances in Solar Cells. Shortcourse David W. Parent. TOPICS. Why we care about solar cell variances. What can vary in a solar cell. Base starting materials Process parameters Circuit parameters Test Bench Steps to reduce variance. Why we care (Company level) .
E N D
Variances in Solar Cells Shortcourse David W. Parent
TOPICS • Why we care about solar cell variances. • What can vary in a solar cell. • Base starting materials • Process parameters • Circuit parameters • Test Bench • Steps to reduce variance
Why we care (Company level) • The solar cell is designed to meet a specified operating voltage and current under a range of conditions. • Devices that depend of solar cells for power are designed to operate at the specification. • If the cells do not perform to specification, the devices that depend on them will not work. • If the cells give power but not the correct amount, it can not be sold. • All the resources used to make that cell are wasted, and this reduces your profit margin. • Solar cells are expensive enough with out “rejects”.
Why we care (System level) • Solar cells are used in arrays. • The arrays consist of parallel and series connections of solar cells. • The cell with the lowest operating voltage and current will dominate the performance of the entire array!
Why we care (System level) • Cells connected in parallel • Current of each cell is added together • Smallest voltage determines output voltage of the entire array. • Cells connected in series • Voltage of each cell is added together • Smallest current determine output current of the entire array.