TY - JOUR

T1 - Homogenous Voltage-Matched Strings Using Three-Terminal Tandem Solar Cells

T2 - Fundamentals and End Losses

AU - McMahon, William

AU - Schulte-Huxel, Henning

AU - Buencuerpo, Jeronimo

AU - Geisz, John

AU - Young, Michelle

AU - Klein, Talysa

AU - Tamboli, Adele

AU - Warren, Emily

N1 - Funding Information: Manuscript received January 7, 2021; revised February 16, 2021; accepted March 18, 2021. Date of publication May 12, 2021; date of current version June 21, 2021. This work was supported in part by the U.S. Department of Energy under Contract DE-AC36-08GO28308 with Alliance for Sustainable Energy, LLC, in part by the Manager and Operator of the National Renewable Energy Laboratory, and in part by the U.S. Department of Energy Efficiency and Renewable Energy Solar Energy Technologies Office under Grant 34911. (Corresponding author: William E. McMahon.) William E. McMahon, Jeronimo Buencuerpo, John F. Geisz, Michelle S. Young, Talysa R. Klein, Adele C. Tamboli, and Emily L. Warren are with the National Renewable Energy Laboratory, Golden, CO 80401 USA (e-mail: bill.mcmahon@nrel.gov; jeronimo.buencuerpo@nrel.gov; john.geisz@nrel. gov; michelle.young@nrel.gov; talysa.klein@nrel.gov; adele.tamboli@ nrel.gov; emily.warren@nrel.gov).

PY - 2021/5/12

Y1 - 2021/5/12

N2 - 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.

AB - 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.

KW - Cell stringing

KW - Doping

KW - Limiting

KW - Photovoltaic cells

KW - Photovoltaic systems

KW - Renewable energy sources

KW - Silicon

KW - tandem cells

KW - three-terminal

KW - voltage-matched (VM)

KW - Wiring

UR - http://www.scopus.com/inward/record.url?scp=85105863641&partnerID=8YFLogxK

U2 - 10.1109/JPHOTOV.2021.3068325

DO - 10.1109/JPHOTOV.2021.3068325

M3 - Article

AN - SCOPUS:85105863641

VL - 11

SP - 1078

EP - 1086

JO - IEEE journal of photovoltaics

JF - IEEE journal of photovoltaics

SN - 2156-3381

IS - 4

M1 - 9429873

ER -