Half-cut solar cells are traditional silicon solar cells that have been cut in half using a laser cutter. They have been mass-produced since around 2019 and have several benefits for solar panel efficiency and performance.
Half-cut cells have reduced resistive losses, improved shading performance, and reduced risk of hotspots compared to traditional solar cells. They also have enhanced temperature coefficients and can use smaller inverters.
These cells are now widely used in solar panels by manufacturers globally and have become a leading technology in the industry.
Half-cut solar cells – is it a leading technology?
Half-cut solar cells were first introduced to the industry by REC Solar in 2014, and they quickly transitioned by this company to using half-cut cell technology across their range. They are traditional square silicon solar cells chopped in half using a laser cutter.
This innovation was introduced into mass production around 2019 and had several benefits regarding the efficiency and performance of solar panels. As a result, most manufacturers globally manufacture panels with half-cut solar cell technology as a critical feature.
Traditional from around 2010 onward solar panels have 60, 66, or 72 square solar cells connected in series via six columns of 10, 11, or 12 square cells, respectively, as per the image below. The 60-cell models are primarily for residential systems, and the 66 and 72-cell versions are for commercial systems.
Implementing half-cut cells in solar panels can enhance the energy output of a solar energy system, just as bifacial solar arrays and PERC solar cells improve the performances of silicon solar cells. Half-cut solar cells have several advantages over standard solar cells.
Half-cut – a simple idea going a long way
Lasers cut square cells in half, forming rectangular cells used in half-cut panels that are then connected in series. The 60, 66, or 72 cell panel still uses the same number of cells; when cut in half, they then have 120, 132, and 144 half cells, respectively.
The panel is divided into two halves, each containing 60 half cells. These halves connect in the middle, combining the current of the top and bottom sections of the panel. This process allows the panel to have voltage and current characteristics similar to a traditional full-square cell panel.
And the benefits are?
If the panels use the same surface area of cells in total over a similar physical size, what are the benefits of the half-cut panels, and how can they produce more power?
How do half-cut solar cells increase panel performance?
Reducing resistive losses
Resistive inefficiencies, or power lost during electrical current transit, represent one form of power loss during the transformation of sunlight into electricity.
By reducing the solar cell’s size by half, the cell’s current reduces by the same proportion (while the voltage remains constant). Moreover, dividing the current in the cell slashes the resistance losses within the cells by up to 75%, enabling the generation of more power in the solar cell, particularly during peak generation periods with high currents.
Furthermore, minimising resistance in the cell generates less heat, thereby improving the panel’s performance on hotter days.
Improved shading performance
Traditional solar cells are more susceptible to the effects of shade than half-cut cells.
This attribute is due to the wiring procedures connecting half-cut cells in a panel, rather than cutting the cells in half. Standard solar panels with full cells link cells in rows via series wiring. In this setup, shading a single cell within a row and its failure to produce energy will halt the entire section of cells from generating energy.
Shade on one unit of one column would remove a third of the panel’s power generation, as earlier generation standard panels typically have three rows of cells linked together.
Half-cut cells link in series, doubling the independent lines compared to full-cut panels due to the doubled cell count. In this setup, panels with half-cut solar cells can minimise energy loss when shading occurs, as a single shaded cell affects only one-sixth of the total panel energy capacity.
Reduced risk of hotspots
By decreasing the current and resistance, the cells generate less heat, so there is a reduced risk of hot spots on panels which can accelerate panel degradation and failure. Hot spotting is when a cell becomes so hot that it can melt the backing sheet and eventually cause the front glass to crack due to a very hot small area on the panel compared to the surrounding areas.
Half-cut solar cells are more structurally resilient than their full-cell predecessors, owing to their smaller size, making them more resistant to shattering. When applied to a panel, the panel structure’s flexibility increases by halving the cell’s size, reducing the risk of cell cracks and cell fractures forming.
Saving raw materials and therefore reducing costs
In the manufacturing process of cells, the total square cells can often develop a blemish or a small crack on the corner. Microcracks in cells, accounting for a maximum of 3% of production, resulted in discarding or cutting such cells into smaller segments for cheaper camping panels, etc.
When utilising half-cut solar cell technology, it’s possible to halve a square cell with a small missing corner. Enabling the use of 50% of the cell in panel manufacturing.
As a result, solar systems with half-cut solar panels can provide faster solar payback times for owners.