In the continuous iteration of crystalline silicon photovoltaic technology, the back-contact structure has become a key direction to break the efficiency bottleneck. By moving all N-type and P-type contact areas and electrodes to the back of the cell, this structure minimizes the front shading loss, increasing the light absorption efficiency of the silicon wafer by more than 5%, and is one of the mainstream technical paths for high-efficiency crystalline silicon cells. Among them, the amorphous-polycrystalline hybrid back-contact structure (HIBC) has achieved dual breakthroughs in efficiency and mass production compatibility through independently innovative technical design.

Traditional back-contact cells have long been restricted by three major problems: the difficulty in simultaneously optimizing the passivation performance and contact resistance of the P-type contact area, the balance contradiction between carrier vertical transmission and lateral leakage, and the carrier recombination and leakage problems in the edge area. Through differentiated process design, HIBC cells creatively adopt low-temperature amorphous silicon contact in the P-type area and high-temperature polycrystalline silicon contact in the N-type area, enabling the two types of contact areas to obtain excellent passivation performance and conductive characteristics respectively, and solving the performance balance problem structurally.

Aiming at the inherent defect of poor vertical conductivity of the P-type amorphous silicon contact layer, the laser-induced local crystallization technology provides a precise solution. This technology only converts the sub-micron scale area at the pyramid tip of the contact area into nanocrystalline silicon. Without affecting the passivation effect of other areas, it reduces the vertical contact resistance by more than 60% while maintaining a low level of lateral leakage in the polarity overlapping area, realizing a leap in carrier transmission efficiency.

The fragility of the edge area is a common problem of back-contact cells. Defects generated during the cutting process can easily lead to serious recombination losses. The application of in-situ edge passivation technology synchronously "wears" a solid passivation layer for the edge during the battery manufacturing process, effectively suppressing edge carrier recombination and increasing the battery fill factor to a new high of 87.55%. At present, the certified efficiency of this type of cell has reached 27.81%, the conversion efficiency of modules based on this technology has reached 25.9%, and the output power of the 2.7-square-meter version has exceeded 700W. Moreover, the core processes are compatible with existing production lines, paving the way for the large-scale application of high-efficiency crystalline silicon cells.

Previous：Frontier Series of Photovoltaic New Energy Technology

Next：Flexible Silicon-Based Tandem Solar Cells: Expanding New Application Scenarios for Photovoltaics