Back-Contact (BC) Modules Have No Front Gridlines — How Do You Read Their EL Images?

ⓘ This article is currently published in Chinese. An English version is being prepared — read the Chinese original.

Back-contact modules — IBC, HPBC, ABC, TBC, HBC — moved all metallization to the rear, so their front side shows no busbars or gridlines. That single change quietly breaks the visual reference frame that PERC and TOPCon EL interpreters have relied on for years. This article explains why BC modules are ramping to gigawatt scale in 2025–2026, how the interdigitated back-contact layout reshapes what a crack, a broken finger or a high-resistance contact looks like on an EL image, why the ultra-uniform front surface raises the bar on camera resolution and signal-to-noise, and how plant owners and module lines should adapt their EL workflow — resolution, current injection and AI-assisted localization — so that BC-specific defects are actually caught instead of hidden inside a deceptively clean-looking picture.