Exploring BC Cells: The Rising Star of the Photovoltaic Industry

Against the backdrop of global energy transition, the photovoltaic (PV) industry, as a cornerstone of new energy, faces unprecedented opportunities and challenges. At the critical juncture of surpassing the 30% conversion efficiency threshold, a disruptive technology—Back Contact (BC) cells—is silently yet powerfully reshaping the entire PV landscape, challenging the current mainstream TOPCon technology. In the near future, this innovative approach of hiding electrodes entirely on the cell’s backside could trigger a full-value-chain revolution from laboratories to production lines. 

I.Structural Revolution: From Physical Reconstruction to Efficiency Leap

In the long evolution of crystalline silicon cells, efficiency enhancement has always been the core pursuit of researchers and industry players, centered on two key goals: capturing as many photons as possible and minimizing energy loss. Traditional PERC cells, though pivotal to the PV industry’s growth, have inherent flaws. Their front-side metal gridlines cause 5–8% optical losses—akin to an unbridgeable black hole restricting further efficiency gains. Each photon striking these gridlines means wasted energy that cannot be converted to electricity, a significant bottleneck for the high-efficiency-oriented PV sector. 

BC cells shatter this dilemma. By a “grand shift” of sorts, they relocate the PN junction and metal electrodes to the cell’s backside. This seemingly simple structural adjustment fundamentally restructures PV cell architecture. The interdigitated back contact design, a highlight of BC cells, eliminates front-side shading losses, allowing more photons to be absorbed unobstructed. Meanwhile, the precise arrangement of back electrodes shortens carrier transport paths by over 40%, reducing energy loss during transmission and boosting overall efficiency. 

Take LONGi Green Energy as an example: its HBC cells achieved a remarkable 26.81% efficiency in 2023. The secret lies in ultra-precise control of back-electrode spacing (reduced to 50 microns, roughly 1/10th the diameter of a human hair) and nanometer-scale surface passivation layer thickness, balancing carrier lifetime and transport efficiency perfectly. 

Compared to mainstream technologies like TOPCon and HJT, BC cells offer unique advantages. Under the same lighting conditions, BC modules can increase power generation per watt by 3–5%—a marginal figure that translates to massive energy gains in large-scale applications. Their weak-light response is particularly outstanding: SunPower’s IBC modules in the U.S. show an 8% power generation boost during dawn and dusk. This makes BC cells highly valuable in distributed scenarios, where shading from buildings or fluctuating light intensity often impacts performance. 

II.Technological Evolution: The Infinite Possibilities of BC+

The true charm of BC technology lies not only in its structural design but in its exceptional compatibility with other advanced technologies. When combined with various innovations, it triggers a “technological nuclear fusion” effect, driving continuous PV cell evolution. 

– TBC (TOPCon+BC) cells introduce a tunneling oxide layer, boosting open-circuit voltage to over 750mV. 

– HBC (HJT+BC) cells integrate amorphous silicon passivation layers, pushing efficiency beyond the 27% theoretical limit. 

Diversified technical routes are reshaping the industry landscape. Aiko Solar’s ABC (All Back Contact) technology uses laser-induced sintering to achieve mass-production efficiency exceeding 26%. Trina Solar’s P-type IBC cells balance cost and performance via selective doping technology. This branching evolution allows BC cells to cater to high-end markets while penetrating mainstream applications. 

Industrial practice validates the potential of technological integration.实测数据 (Field data) from Kaneka’s HBC modules in Dubai’s PV power plants show a bifacial ratio of 75%, with annual power generation 12% higher than PERC modules. This “1+1>2” synergy is rewriting the value evaluation system for PV technologies. 

III. Cost Breakthrough: From “Noble Technology” to Mass Adoption 

Despite their superior performance, BC cells face a core paradox in industrialization: exceptional quality comes with high costs. First, material costs: silver paste consumption per BC cell reaches 180mg, 2.5 times that of TOPCon cells. Second, equipment costs: imported laser patterning systems cost over 30 million RMB each, driving single-GW equipment investment to 400 million RMB. 

However, cost-reduction technologies for BC cells are breaking through on multiple fronts: 

-Material innovations**: Maskless laser transfer technology reduces silver paste consumption by 30%, while copper electroplating (replacing silver paste) is in pilot testing. 

-Equipment upgrades**: Meyer Burger’s BC-dedicated PECVD equipment costs 40% less than imports but achieves ±3μm precision. 

These innovations form a “compound slope” for cost reduction, driving BC cell costs down by 15% annually. Scale effects are also kicking in: expanding capacity from 1GW to 10GW reduces equipment depreciation costs by 60% and auxiliary material costs by 25%. LONGi’s 30GW BC cell base in Ordos marks the industry’s entry into a new phase of scale-driven cost reduction. By 2026, BC module costs are expected to match TOPCon, triggering a market revolution. 

IV.Application Revolution: Reconstructing the Value of PV Products

In the distributed PV market, BC modules are redefining product value. Colored BC photovoltaic curtain walls maintain 18% conversion efficiency while achieving 90%+ color saturation, transforming PV modules from “appendages” to “value creators” in architecture. 

At the tipping point of PV technological revolution, the rise of BC cells is no accident. It represents the PV industry’s profound shift from “manufacturing-oriented” to “technology-oriented”. As conversion efficiency approaches theoretical limits, the systematic advantages of structural innovation become increasingly prominent. BC technology is not just a product innovation but a milestone in reconstructing PV industry value. With falling costs and expanding applications, this technological revolution triggered by “invisible electrodes” will illuminate a new era for the PV industry, powering global energy transition and sustainable development.