Solar cell and module baselines are executed at regular intervals. The baselines contain processes and photovoltaic materials that are relevant for the SiCC partners. They form a stable test platform for comparing new process steps and materials, and demonstrating partner tools and processes.
Controlled silicon photovoltaic cell upgrades are introduced in order to keep the baseline performance up to state-of-the art. Improved processes and photovoltaic materials are integrated after qualification and validation according to the baseline protocol.
Silicon PV cell baselines
The bi-monthly bifacial n-PERT baseline mainly aims at proofing and quantifying the stability of the SiCC n-type platform. It also indicates deviations that are not signaled in standalone tests for the individual processes.
Average efficiency with this industrial PERPoly process flow (see ‘n-type Polysilicon passivating contact for industrial bifacial n-PERT cells’ <download> ) reaches up to 21% in the baselines, while top efficiencies up to 21.5% have been achieved (‘Material properties of LPCVD processed n-type polysilicon passivating contacts and its application in PERPoly industrial bifacial solar cells’ <download> and a more recent EUPVSEC presentation with the latest result). Special feature of these cells is a high bifaciality of ~90%.
The back contact n-type Mercury IBC baseline runs proof the stability of the industrially feasible lean process flow for this advanced IBC concept. Mercury IBC cells feature high performance, aesthetic appearance, and are compatible with conductive backsheet and multi-wire interconnection. Details on the process flow and efficiencies have been published in reports ‘Enablers for IBC: integral cell and module development and implementation in PV industry’ <download> and ‘Pilot line results of N-type IBC cell process in mass production environment’ <download>.
Solar module baselines
The module baselines are based on the quarterly build of 4-cell modules. They include durability testing in damp heat and thermal cycle. The modules are tested until the power loss exceeds 5 percent. A few modules per run are used for other purposes such as PID or outdoor testing. The baselines are based on two module concepts, viz. bifacial and back-contact:
The bifacial baseline consists of glass-glass modules with industrially produced n-type bifacial cells. The cell tabbing is done by a lab-scale tabber-stringer with controlled temperature profile. The glass-glass laminator has top and bottom heating.
The back-contact baseline consists of modules with front side glass and conductive back sheet with industrially produced p-type MWT-cells. The back contact modules are manufactured on a lab scale back contact module line.