Technology R&D is one of the four core competencies of Tongwei. Tongwei has now carried out R&D projects on TOPCon, HJT, IBC, perovskite, and other technologies, all equipped with excellent test lines, laboratories, and other R&D facilities. In terms of Tongwei TNC, based on the self-developed "TNC" technology, Tongwei has achieved pilot line cell efficiency of 25.8% (the highest industrialized efficiency of M10 silicon wafers) and the mass production cell efficiency of 25.5%. In terms of Tongwei THC, Tongwei broke the world record of mass production cell efficiency with an astonishing figure of 26.18% in March 2023. In 2023, Tongwei has beaten the world record for the power of heterojunction modules three times, marking its entry into the era of 730W.
The company has formed a series of fully-flexible, zero-lead, eco-friendly shingled modules and high-efficiency half-cell modules, such as P-type, and the popular N-Type TOPCon and HJT models. They deliver less LCOE (Levelized Cost Of Electricity) for customers.
The half cut solar panel is a newer technology for improving the cells’ power output. Just as the bifacial and PERC solar cells offer improved efficiency, using half cut solar cells boosts the power output. The standard solar panels are just a combination of solar cells combined to create a certain wattage. In comparison, the half cut solar modules are halved solar cells connected to obtain the desired watt.
So, it’s just a design for boosting power output. For instance, instead of 50 solar cells, you can use 100 half cut solar cells. What’s the difference? The half cut solar modules provide higher power output, durability, and performance compared to the traditional solar cells. In addition, they are smaller in size and designed to resist cracking.
They are traditional mono or polycrystalline cells just cut in half using laser cutters. But what’s the science in it? How the power output increases just by cutting the solar cells in half? Following are the major reasons for the boost in power output.
In 2016, Tongwei gradually started its explorations in the shingled panel and committed to developing and producing shingled products. Through continuous technology and market exploration, Tongwei has formed a Terra shingled panel products with Tongwei characteristics, including Terra-5K, Terra-5E, Terra-N, and other product families focusing on prime distributed scenarios. Terra series conforms to the global trend of carbon reduction, focuses on the goal of green development, safety, and efficiency, and has several significant advantages such as high output and high efficiency, high reliability, environmentally friendly, and beautiful appearance.
Reduction in resistance losses
- Multi-busbar - reduced strings increase output, dense wires reduce losses The grid lines are densely distributed, and the stress is uniform with SMBB design, Significantly reduce BOM cost, and the output power is 1-2W higher than that of MBB
-Half-cell cut - reduce flow and loss Current density is reduced by 1/2, internat power loss is reduced to 1/4 of conventional modules, and the rated output power is increased by 5-10w
-Shading, not compromising energy :Up-down symmetrical parallel module design, effectively reduce current mismatch due to shading. The power output is increased by 50%
-Lossless laser cutting technology, no mechanical damage, smooth cutting surface without burrs. Low cell cracking risks, micro-cracking is reduced by more than 50%
-Adopt round-shaped solder ribbon, low shading area, Multiple reflections of incident light, power increased by 1-2W
-The 210 Series adopts advanced high-density encapsulation technology to ensure the perfect balance of efficiency and reliability. Module efficiency increased by more than 0.15%
One of the significant power losses in converting sunlight to electricity is resistive losses. They are due to transferring current from solar panel wires to the home cables. The solar cells transfer current by thin metal wires where the current loses some power due to resistance.
However, when the cell is cut in half, the current produced in each cell is halved. It results in lower current flowing and thus lower resistive losses. As a result, the power output increases and is greater compared to the standard solar modules. Generally, the half cut solar cells provide power output between 5W – 8W per module. However, it’s totally dependent on the design and cell type
Higher Shade Tolerance
The solar panel half cut module offers more shade resistance than the full module cells. It’s not due to half-cut design but the difference in the wiring method. The traditional solar panels have series wiring and are thus badly affected by shade. In a series wiring, the entire row will stop producing power if only one cell is in shadow. In general, the solar panels have three different rows connected together. So, if one cell is in the shades, it would cut almost one-third of that panel’s energy production.
However, the half cut solar panels have higher shade tolerance despite the series wire connection. They have a greater number of cells and, therefore, a greater number of separate rows. For example, the number of cells in half cut solar module is 100 instead of 50. In this case, a single shaded cell would decrease one-sixth of the total power output. For that reason, they are more shade resistant.
Hot Spots
If any one of the solar cells is shaded, all the other unshaded cells dump the energy into the first shaded cell. In this way, all the heat collects in one spot called the hot spot. It can potentially damage the solar cells if it lasts longer.
In the case of a full module, the hot spots affect a larger area since the number of cells is less. However, if it is a half cut solar panel, it means less heat because a half cell is shaded compared to the full solar module. In simple words, the half cut solar cells dump half heat compared to the full solar panel. So, it means less damage and more life.
1. Superior performance
The half cut solar panel efficiency is higher than standard solar modules. They provide higher power output due to following reasons:
-Reduction in resistive losses
-Higher shade tolerance
-Lesser hot spot effects
2. More durability
Besides higher output, the half-cut cells offer longer service life and thus are more reliable. They are highly crack-resistant, thanks to their compact structure. For these reasons, most farms and homes prefer half cut solar modules since they provide a faster return on investment. Moreover, they easily fit in compact places no matter the sunlight’s intensity.
3. Higher power output in low-light conditions
The mono half cut solar panels have more cell numbers and lesser resistance. In shades, the current face less resistance, all thanks to a large number of rows. Therefore, the power output is higher compared to conventional full cell solar panels.
4. Higher CTM power
The half cut solar modules have higher Cell-to-Module (CTM) power, which boosts power output. Conventional full cell solar panels have 94.8% CTM power. On the other hand, the half cut solar panels provide 99.4%, neglecting the laser-cut losses. Considering losses, it still provides 98.4% CTM power which is higher than traditional solar panels. However, their conversion efficiency is entirely dependent on the type of solar cell technology.
5. Compatible with various solar cell technologies
Half cut solar modules are an alteration in the PV modules manufacturing process using traditional c-Si technology for solar cells. As a result, they can be manufactured using PERC or bifacial technologies. Using these technologies, the half cut solar panels provide higher power output, fewer losses, and multiple other benefits.
