Half-cut Cell

What half-cut cells are

Half-cut cells are standard solar cells laser-cut into two halves. The half-cells are then assembled into a solar panel with the internal wiring arranged as two parallel sub-strings, where each sub-string carries half the current of an equivalent full-cell design.

The technology is now standard in most premium and commercial solar modules. Half-cut Mono PERC, half-cut TOPCon, and half-cut HJT have replaced full-cell variants in most market segments.

The benefits come from physics. Resistive losses in series circuits scale with the square of current (I squared R). Halving the current quarters the resistive losses in cell interconnects, ribbons, and busbars. The resulting energy improvement is 2% to 3%, with additional benefits from cooler operation and better shading tolerance.

How half-cut cells work

The manufacturing process modifies a standard cell production line:

Standard cell production proceeds normally (texturing, diffusion, passivation, metallisation).

Before final assembly, each cell is laser-cut in half. The cut is precise, perpendicular to the busbars, dividing the cell into two electrically separate halves.

The half-cells are assembled into a panel. The panel layout differs from full-cell modules: cells are wired in two parallel sub-strings, each occupying half the panel.

The two sub-strings have separate ribbon paths and separate bypass diode protection.

The combined output is taken from the junction box on the panel back.

A modern 144-half-cut-cell module is equivalent to a 72-cell full-cell module in cell area, with the benefits of half-cut wiring.

Why half-cut improves performance

The main benefits are:

Resistive loss reduction: Internal current is halved. Resistive losses (I squared R) are quartered. Series resistance losses reduce from 3% to about 0.75% of generation.

Better shading tolerance: Two independent sub-strings mean shading on one half does not affect the other half. The panel has effectively 6 diode groups (3 per sub-string) instead of 3, providing finer shading protection.

Cooler operation: Less resistive heating means lower cell operating temperature. Lower temperature improves cell efficiency and reduces degradation rate.

Higher fill factor: Better current collection at the high-current end of the cell’s I-V curve.

Reduced mismatch: Smaller mismatch impacts on the overall module performance.

The combined benefit is 2% to 3% higher module output for the same cell technology and area.

Half-cut module construction

A typical 540 Wp half-cut Mono PERC module has:

144 half-cells arranged in 6 columns of 24 half-cells.

Two parallel sub-strings, each with 72 half-cells.

Each sub-string has 3 bypass diodes (totalling 6 diodes in the panel).

Multi-busbar interconnection (typically 9 to 16 busbars per cell) for further resistance reduction.

Glass-glass or polymer backsheet construction.

EVA or POE encapsulant.

Anti-reflective coated front glass.

The internal wiring is more complex than full-cell modules but mass production has solved the manufacturing challenges. Half-cut modules are now standard.

Half-cut versus full-cell modules

For most applications, half-cut delivers better economics through higher output and reduced shading sensitivity.

Half-cut in Indian market

Half-cut cell modules are now standard in ALMM-listed Indian products. All major Indian manufacturers (Adani Solar, Vikram Solar, Waaree Energies, Tata Power Solar, Premier Energies, Renew, RenewSys, JNK India, Goldi Solar, Servotech) produce half-cut Mono PERC and increasingly half-cut TOPCon modules.

For residential PM Surya Ghar installations: Half-cut Mono PERC is the default choice.

For commercial rooftop: Half-cut Mono PERC dominates, with half-cut TOPCon gaining share in larger projects.

For utility-scale: Half-cut TOPCon (or half-cut bifacial TOPCon) is standard in new SECI tenders.

The transition from full-cell to half-cut happened gradually between 2018 and 2022. By 2026, full-cell modules are rare in new installations.

Combining half-cut with other technologies

Half-cut is compatible with all silicon cell technologies and design improvements:

Half-cut Mono PERC: Standard mass-market combination.

Half-cut TOPCon: Premium combination for commercial and utility-scale.

Half-cut HJT: Highest-end combination for premium installations.

Half-cut bifacial: Adds rear-side absorption to half-cut benefits.

Half-cut multi-busbar: Combines half-cut with 9 or 16 busbars instead of 5, further reducing resistive losses.

Half-cut smart-wire: Uses fine copper wires instead of busbars; some HJT designs.

The combinations are additive. A modern premium module typically combines half-cut, multi-busbar, bifacial, and a high-efficiency cell architecture (TOPCon or HJT).

Common mistakes regarding half-cut

Treating half-cut as a marketing label. The internal architecture matters; verify the cell layout.

Comparing full-cell and half-cut on nameplate Wp without considering operating temperature. Half-cut runs cooler.

Mixing half-cut and full-cell modules in one string. Different I-V characteristics cause mismatch.

Ignoring the additional bypass diodes. Half-cut modules have 6 effective diode groups; shading tolerance is better.

Assuming half-cut costs significantly more. The manufacturing cost difference is small in 2026.

Best practices

For new module procurement, specify half-cut cell modules as a baseline.

For shading-heavy installations, half-cut provides meaningful additional shading tolerance beyond bypass diodes alone.

For commercial and utility-scale projects, half-cut TOPCon delivers the best combination of efficiency and cost.

For monitoring, the dual-sub-string design means string current measurements should align with sub-string current expectations.

For warranty claims involving half-cut modules, document the specific sub-string affected.

Standards and references

Half-cut cell modules comply with IEC 61215 (design qualification), IEC 61730 (safety), and IEC 62804 (PID). ALMM-listed half-cut modules require BIS certification. Test methodologies for half-cut are addressed in IEC test standards.

Related glossary terms

• Mono PERC
• TOPCon Solar Panel
• HJT Solar Panel
• Bifacial Solar Panel
• Bypass Diode
• Busbar in Solar Panel
• PERC Cell Architecture
• ALMM

Key takeaways

Half-cut cell technology splits each solar cell into two halves with a laser cutter, then wires the panel internally as two parallel sub-strings. This reduces internal current by half, lowers resistive losses to a quarter of full-cell levels, raises panel output by 2% to 3%, improves shading tolerance through 6 effective diode groups, and reduces operating temperature. Half-cut design is standard in premium and commercial solar modules in 2026, with all major Indian manufacturers producing half-cut Mono PERC and increasingly half-cut TOPCon modules.