Silicon Heterojunction and Half-Cell configuration: optimization path for increased module power

Half-cell integration is a smart way to improve module output powers without modifying the global cell architecture. If shingle/half-cell is highly used in standard PV cell technologies, this configuration appears much more challenging when high passivation cell concepts are considered. Indeed, a strong cell degradation is systematically observed for example on silicon heterojunction (SHJ) solar cells after cutting, mainly because of the un-passivated edge created. This paper intends to present recent developments done at CEA-INES on the SHJ half-cell topic. In particular, insights on loss mechanisms and cleavage process conditions are presented, allowing the optimization of the laser cutting process. Best cells were then successfully integrated into a 120 half-cell module, delivering a very high 348W output power under standard conditions. Final power gain of ~+7W was estimated on this module thanks to the specific half-cell architecture demonstrating that half-cell configuration is also fully adapted to the SHJ technology. Finally, hints on further cell performance improvement paths are introduced, with the use for example of localized re-passivation processes to minimize cutting induced degradations.