Shingled Solar Cells Explained: How Overlapping Strips Boost Panel Output

Shingled solar cells are narrow cell strips overlapped like roof shingles and bonded with electrically conductive adhesive, eliminating busbars and cell gaps to increase active area by 3-5%. This design produces 2-3% more power per square meter than conventional cell interconnection, improves shade tolerance through parallel sub-string architecture, and reduces resistive losses. Used by SunPower/Maxeon and Solaria among others, shingled cells represent a premium approach to maximizing module power density.

How shingled cells are made

The shingled cell manufacturing process starts with a standard full-size solar cell (typically 182mm or 210mm). A laser scribes the cell into 5-6 narrow strips, each roughly 30-40mm wide. The strips are then arranged so that the front edge of one strip overlaps the rear edge of the adjacent strip by about 1-2mm, much like how roof shingles overlap.

The overlapping edges are bonded with an electrically conductive adhesive (ECA), a specialized polymer loaded with silver or copper particles. The ECA simultaneously creates the electrical connection between the positive contact of one strip and the negative contact of the next, and mechanically holds the strips together. No ribbon busbars or soldering are needed.

These bonded strip assemblies are then arranged into strings and wired into the module. Because the strips are narrower and carry less current individually, they can be wired into parallel sub-string configurations that offer better shade tolerance than the purely series-connected strings in conventional modules.

Why removing busbars matters

In a conventional solar cell, busbars are metal fingers printed on the front surface that collect current and route it to ribbon interconnects. These busbars create two types of losses.

Shading loss: The busbars physically block sunlight from reaching the silicon underneath. A typical 5-busbar cell loses about 2-3% of its surface area to busbar shading. Even multi-busbar designs (9-12 busbars) with thinner fingers still shade 1-2% of the cell area.

Resistive loss: Current must travel along the busbar to reach the ribbon interconnect at the cell edge. The longer this path, the more energy is lost to resistive heating. Multi-busbar designs reduce this by providing more collection points, but the fundamental resistive loss remains.

Shingled cells eliminate both losses. There are no busbars on the front surface — the overlap region serves as the interconnect, and it is hidden under the adjacent strip rather than blocking sunlight. The current path is also shorter because each narrow strip collects current over a much smaller area.

Feature	Conventional (5-busbar)	Multi-busbar (9-12BB)	Shingled
Busbar shading loss	~2.5%	~1.5%	0%
Cell gap area loss	~2-3%	~2-3%	0% (overlapped)
Total inactive area	~5%	~4%	~1% (edge only)
Relative power gain	Baseline	+1-2%	+2-3%

Shade tolerance: the parallel advantage

Shade performance is where shingled cells offer their most noticeable real-world benefit. In a conventional module, cells are wired in series within each string. When one cell is partially shaded, its current drops, and because all cells in the string must carry the same current, the entire string's output drops to match the weakest cell. Bypass diodes limit the damage by bypassing groups of cells, but they operate in coarse groups (typically one diode per 20-24 cells).

Shingled modules can be wired so that strips form parallel sub-strings across the width of the module. When a shadow (from a vent pipe, chimney, or tree branch) covers one strip, only that sub-string's contribution is lost. The other parallel sub-strings continue operating at full power. The result is a more proportional relationship between shaded area and power loss.

For a rooftop with partial shading from nearby obstructions, this can translate to 5-10% higher annual energy production compared to a conventional module, depending on the shading pattern. For unshaded rooftops, the benefit is limited to the 2-3% power density gain.

Shingled cells vs other interconnection technologies

The solar industry has developed several approaches to reducing interconnection losses. Understanding where shingled fits helps put it in context.

Half-cut cells cut standard cells in half (two pieces instead of five or six), reducing current per cell by 50% and cutting resistive losses by 75%. Half-cut is now the industry standard, used in the vast majority of modern panels.

Multi-busbar (MBB) increases the number of busbars from 5 to 9-16, using thinner round wire instead of flat ribbon. This reduces both shading and resistive losses compared to 5-busbar designs. MBB is widely adopted and often combined with half-cut.

Shingled goes further by eliminating busbars entirely, but at higher manufacturing complexity and cost. The ECA bonding process requires precise temperature and pressure control, and the adhesive material itself adds cost.

In practice, most mainstream panels in 2025-2026 use half-cut cells with multi-busbar interconnection, which captures most of the available efficiency gains at low manufacturing cost. Shingled cells are a premium option for applications where maximum power density and shade tolerance justify the additional expense.

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Frequently Asked Questions

What are shingled solar cells?

Shingled solar cells are standard solar cells that have been laser-cut into narrow strips (typically 5-6 strips per cell) and then overlapped slightly, like shingles on a roof. The overlapping edges are bonded together with an electrically conductive adhesive (ECA) that serves as both the mechanical connection and the electrical interconnect. This design eliminates the need for traditional ribbon busbars and the cell-to-cell gaps that exist in conventional modules, allowing more of the module's surface area to be covered by active silicon.

How much more efficient are shingled cell panels compared to standard panels?

Shingled cell modules typically produce 2-3% more power per square meter than conventional modules using the same cell technology. This gain comes from two sources: increased active area (eliminating busbars and cell gaps recovers about 3-5% of module surface area) and reduced resistive losses (the shorter current path in each strip and the distributed contact reduce series resistance). A conventional 400W panel might produce 410-412W in a shingled configuration with the same outer dimensions.

Why are shingled cells more shade tolerant?

In a conventional panel, cells in each string are connected in series, so shading one cell reduces current for the entire string. Shingled modules wire the overlapping strips into multiple parallel sub-strings. When one strip is shaded, only that sub-string is affected while the others continue operating normally. This parallel architecture means partial shading causes a proportional power loss (shade 10% of the module, lose roughly 10% of power) rather than the disproportionate losses seen in conventional series-connected modules.

Which manufacturers make shingled cell solar panels?

SunPower/Maxeon is the most well-known manufacturer using shingled-like interconnection in their Performance series panels (their higher-end Maxeon panels use IBC cells with a different interconnection). Solaria uses shingled cells in their PowerXT residential modules. Several Chinese manufacturers including Yingli, Seraphim, and Canadian Solar have produced shingled cell modules. However, shingled technology remains a niche approach, representing well under 10% of global module production, because the conductive adhesive bonding process adds manufacturing complexity and cost.

What is the difference between shingled cells and half-cut cells?

Half-cut cells are standard cells cut in half and wired with conventional ribbon busbars, reducing resistive losses by halving the current per cell. Shingled cells are cut into 5-6 narrow strips that overlap physically, eliminating busbars entirely. Half-cut cells still have cell gaps and busbar shading losses; shingled cells eliminate both. However, half-cut technology is much simpler to manufacture and has been adopted by virtually all major producers, while shingled remains a specialty design with higher manufacturing cost.

Do shingled cells have reliability concerns?

The primary reliability concern is the conductive adhesive bond between overlapping strips. Unlike traditional soldered ribbon connections, ECA bonds must maintain both electrical conductivity and mechanical adhesion for 25-30 years through thermal cycling, humidity, and UV exposure. Early shingled modules had some field issues with adhesive degradation, but modern formulations have largely addressed this. Leading manufacturers now pass IEC 61215 accelerated aging tests with wide margins. Long-term field data (10+ years) is still limited compared to conventional modules with decades of track record.

Are shingled cell panels worth the premium?

Shingled panels make the most sense when roof space is limited and you need maximum power from every square meter. The 2-3% power density advantage plus better shade tolerance can be meaningful on constrained rooftops with partial shading. However, if your roof has ample space and minimal shading, a conventional half-cut cell panel at a lower price per watt will likely give you better economics. The premium for shingled modules is typically 5-15% above comparable conventional panels, which may or may not be justified by the modest efficiency gain.

Sources

Marko Visic

Physicist and solar energy enthusiast. After installing solar panels on my own house, I built TheGreenWatt to share what I learned. All calculators use NREL PVWatts v8 data and peer-reviewed formulas.