What is IBC Photovoltaic Module Technology?
What is IBC Technology?
- The IBC (Interdigitated Back Contact) solar cell is designed with its positive and negative metal electrodes strategically placed in a fork-like configuration on the rear side, away from direct sunlight exposure. This innovative layout eliminates shading on the cell’s surface, enhancing its overall efficiency.
- MWT (Metal Wrap Through) and EWT (Emitter Wrap Through) are also classified as back contact solar cells. However, their P-N junctions are situated on the front surface, categorizing them as front-junction back contact solar cells.
- Unlike these designs, the P-N junction in IBC cells is positioned entirely at the back, allowing current to travel through a two-dimensional pathway, optimizing electrical transmission.
Structure of IBC Solar Cells
All metal contacts in IBC (Interdigitated Back Contact) solar cells are positioned on the back side of the cell. This design eliminates shading on the front surface, ensuring maximum light absorption. By placing contacts more widely on the back, series resistance is reduced, improving the cell’s efficiency.
The primary absorption layer in an IBC solar cell is a crystalline silicon (c-Si) wafer, which can be either n-type or p-type. This layer is created by doping the silicon with boron or phosphorus, depending on the desired polarity. To further enhance the cell’s performance, a passivation and anti-reflective coating, typically made of SiO, is applied to minimize reflection and protect the surface.
Another key feature of IBC cells is the diffusion layer, where n-type and p-type regions intersect. This configuration enables the integration of back-side metal contacts and supports efficient current flow through the cell.
IBC (Interdigitated Back Contact) solar cells are primarily built using crystalline silicon (c-Si) wafers as the absorption layer, with n-type wafers being the standard choice due to their superior performance. P-type wafers are also used in certain cases. Among the c-Si options, monocrystalline silicon (mono c-Si) is favored for its higher efficiency, while polycrystalline silicon (poly c-Si) remains a viable alternative.
To enhance the efficiency of c-Si wafers, an anti-reflective and passivation layer is applied to one or both sides. This layer is often composed of silicon dioxide (SiO2), which is thermally oxidized, though other materials like silicon nitride (SiNx) or boron nitride (BNx) are also effective in minimizing reflection and protecting the wafer’s surface.
Repositioning the front contacts to the rear side requires the creation of diffusion layers, comprising intersecting n+ and p+ emitter layers. These are formed using advanced techniques such as masked diffusion, ion implantation, or laser doping with boron. This process ensures the integration of p-type regions into the n-type wafer while maintaining its structural and electrical integrity.
The final step involves placing metal contacts exclusively on the back of the cell. Techniques such as laser ablation or wet chemical deposition are employed for this purpose. Metals like silver, nickel, or copper are commonly used, providing reliable electrical conductivity and durability for the solar cell.
Perc, TOPCon, and IBC Technologies Compared
| IBC | TOPCON | PERC | |
|---|---|---|---|
| Appearance | Without busbars on the front | Standard | Standard |
| Power degradation in the first year | 1.5% | 1.5% | 2% |
| Average annual power degradation | 0.4% | 0.4% | 0.45% |
| Efficiency | 22.5%-23.2% | 22.28% | 21.2% |
| Temperature Coefficient | -0.29%/℃ | -0.32%/℃ | -0.35%/℃ |
Advantages of IBC Technology
- The absence of metal lines on the front of the solar cell eliminates shading, allowing for full utilization of incident photons and minimizing current loss. This design significantly enhances efficiency, with the short-circuit current increasing by approximately 7% compared to traditional solar cells.
- By positioning the positive and negative electrodes on the back of the cell, grid line shading becomes unnecessary. This layout allows for larger grid lines, effectively reducing series resistance and improving the fill factor (FF) for better overall performance.
- Additionally, optimized surface passivation and advanced surface trapping structures minimize front surface recombination and reduce reflection. This leads to improved open-circuit voltage (VOC) and short-circuit current density (JSC), as the front side remains free from shading or metal contacts.
- Beyond its technical advantages, this design is visually appealing, making it ideal for building-integrated photovoltaics (BIPV) and enhancing its commercial potential.
Development direction of IBC solar cell efficiency
IBC solar cells leverage advanced Interdigitated Back Contact technology, positioning all contacts on the rear side of the cell. This innovative design eliminates shading on the front surface, significantly reducing current losses and achieving exceptional energy conversion efficiency.
Low temperature coefficient
IBC solar panels offer superior stability in high-temperature conditions compared to traditional panels. With a temperature coefficient of -0.29%/℃, these panels are designed to reduce internal resistance and minimise heat loss, ensuring consistently high conversion efficiency even in elevated temperatures.
Forecast of Future Development of IBC Solar Cells
According to Kopecek in an interview with PV Magazine, “By 2028, IBC solar modules could surpass TOPCon as the dominant product in the market.” The shift toward IBC technology may begin as early as 2025, with traditional solar products gradually phasing out by 2030.
Kopecek further highlighted the rapid growth of IBC solar modules in the global market. Their market share is projected to increase from approximately 2% in 2022 to 6% by 2026, potentially reaching 20% by 2028 and surpassing 50% by 2030.
Reference：
https://www.pv-magazine.de/2022/11/03/zelltechnologie-ibc-koennte-topcon-bis-2028-vom-markt-verdraengen/
https://solarmagazine.com/solar-panels/ibc-solar-cells/
https://www.energiemagazin.com/photovoltaik/ibc-technologie-solarzellen/
Maysun IBC Solar module
Efficiency: 21-22.5%
Dimensions (L × W × H): 1722 x 1134 x 30 mm
Weight: 20.8kg
Packaging:36 pieces/pallet, 936 pcs/40'HQ
Warranty: 25-year performance warranty
Efficiency: 21.7-23.1%
Dimensions (L × W × H): 1722 x 1134 x 30 mm
Weight: 20.8kg
Packaging: 36 pcs/pallet, 936 pcs/40'HQ
Warranty: 25-year product and performance warranty
Efficiency: 21.5-23.2%
Dimensions (L × W × H): 2278 x 1134 x 30 mm
Weight: 27.5 kg
Packaging: 36 pcs/pallet, 720 pcs/40'HQ
Warranty: 25-year product and performance warranty
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