Homogenous Voltage-Matched Strings Using Three-Terminal Tandem Solar Cells

Fundamentals and End Losses

authored by

William McMahon, Henning Schulte-Huxel, Jeronimo Buencuerpo, John Geisz, Michelle Young, Talysa Klein, Adele Tamboli, Emily Warren

Abstract

Strings constructed from three-terminal tandem (3TT) solar cells offer the performance benefits of voltage-matching (which reduces sensitivity to spectral variation), but without the subcell voltage isolation required by four-terminal cells. However, the circuitry for a 3TT string can become complex, making circuit analysis more challenging. Here, we illustrate the essential features of 'homogenous' voltage-matched (VM) 3TT strings, for which all 3TT cells in the string are nominally identical (with the same design/doping sequence, such that they can be fabricated on the same manufacturing line). Several representative VM string configurations are explicitly considered, and used to describe the general construction of string I(V) curves. End losses intrinsic to these strings are discussed in detail, along with mitigation strategies to minimize their impact. Our analysis agrees with experimental results for eight-cell strings constructed from GaInP/GaAs 3TT devices.

External Organisation(s)

National Renewable Energy Laboratory
Institute for Solar Energy Research (ISFH)

Type

Article

Journal

IEEE journal of photovoltaics

Volume

11

Pages

1078-1086

No. of pages

9

ISSN

2156-3381

Publication date

12.05.2021

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials, Condensed Matter Physics, Electrical and Electronic Engineering

Sustainable Development Goals

SDG 7 - Affordable and Clean Energy

Electronic version(s)

https://www.osti.gov/biblio/1785087 (Access: Open)
https://doi.org/10.1109/JPHOTOV.2021.3068325 (Access: Closed)