A new era of high-efficiency solar technology: How BC and TOPCon cells reshape the future of photovoltaics

  Under the global wave of pursuing carbon neutrality, solar panel technology is undergoing disruptive changes. As the two cutting-edge technologies in the photovoltaic industry, BC cells (back contact cells) and TOPCon cells (tunnel oxide passivation contact cells) are accelerating the upgrading of the photovoltaic industry with higher conversion efficiency and differentiated advantages.

Technical core: Structural innovation determines performance boundaries

BC cells: "unobstructed design" with extreme efficiency

BC cells use back contact electrode technology to move all metal grid lines to the back of the cell, without any obstruction on the front. This design maximizes the light absorption area, with laboratory efficiency exceeding 26% and mass production efficiency stable at 24%-25%. Its iconic advantages include:

Higher power output: Under the same area, the power generation of BC components increases by 5%-10%, which is especially suitable for space-constrained scenarios such as rooftop photovoltaics.

Aesthetic advantage: The all-black appearance is perfectly integrated with the building, making it the preferred solution for BIPV (building integrated photovoltaics).

TOPCon cells: a master of balancing cost-effectiveness and efficiency

Based on the traditional PERC battery, TOPCon significantly reduces carrier recombination through the passivation contact structure of ultra-thin silicon oxide layer + doped polysilicon layer. The mass production efficiency has reached 24%-25.5%, and it has stronger cost advantages:

Production line compatibility: It can be upgraded on the existing PERC production line, and the equipment transformation cost is reduced by 30%-50%.

Thinning potential: Supports silicon wafers below 130μm, further reducing material costs.

Market structure: opportunities and challenges under the differentiation of technical paths

According to the SPE Global 2024 Photovoltaic Technology Report, TOPCon has occupied 70% of the new production capacity with its high cost-effectiveness and has become the mainstream choice for ground power stations. BC batteries are currently focused on the high-end distributed market due to their complex process and high cost, but their share is growing at a rate of 15% per year.

Key market dynamics:

TOPCon capacity explosion: In 2024, the global TOPCon capacity will exceed 500GW, and leading companies such as Longi and Jinko will accelerate their layout, driving a significant drop in the cost per kilowatt-hour.

BC technology breakthrough: SunPower and Longi cooperate to expand IBC module production capacity, targeting the European and American household markets, with a premium space of 8%-12%.

Policy-driven: The EU's Renewable Energy Directive requires new buildings to install solar panels. The high efficiency and aesthetic characteristics of BC may become the biggest beneficiary of policy dividends. 

Application scenarios: How to choose the best solution?

Household and industrial and commercial roofs: Give priority to BC battery components to achieve higher returns with limited area, while enhancing the aesthetic value of the building.

Large ground power stations: TOPCon has become an economic choice for large-scale applications with its low electricity cost and rapid expansion capabilities.

Extreme environment projects: BC batteries have lower performance degradation in high temperature areas due to their low temperature coefficient (-0.29%/℃), and are suitable for markets such as the Middle East and Australia.

Future trends: Efficiency competition and technology integration

The photovoltaic industry is moving towards the "26%+" efficiency era, and two major technical routes continue to evolve:

TOPCon upgrade direction: Through the optimization of double-sided Poly-Si and metallization processes, the mass production efficiency is expected to exceed 26% in 2025.

BC technology breakthrough: laser transfer and maskless processes drive down costs, and the laboratory efficiency of HBC technology combined with HJT (heterojunction) has exceeded 26.5%.

Conclusion: Technology-oriented, scenario-based

Whether it is the BC battery that pursues extreme efficiency or the TOPCon technology that wins with cost-effectiveness, it marks that solar panels have entered an era of high efficiency and refinement. Enterprises need to choose appropriate technical solutions based on project requirements, budgets and long-term benefits. With the advancement of technology and the release of scale effects, the "win-win competition" between BC and TOPCon will continue to promote the photovoltaic industry to reduce costs and increase efficiency, and accelerate the global energy transformation process.