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Advent Solar Ventura Technology
Advent Solar, Inc. is a leading innovator of next generation silicon-based solar technology. In 2008, Advent Solar introduced Ventura™ Technology, the solar industry’s only comprehensive cell-to-module solar architecture. Advent Solar® Ventura™ Technology combines Emitter Wrap-Through (EWT) back-contact cells designed to eliminate grid obstruction with Monolithic Module Assembly (MMA) – a fully automated module assembly process that applies proven, high volume, high precision, semiconductor-style manufacturing techniques. Ventura Solar Technology is designed to achieve the optimal balance between efficiency and cost – maximizing module energy output with minimal interconnect resistance, based on efficient, repeatable manufacturing processes to reduce costs.
DESCRIPTION
Advent Solar’s leading team experts sought to address key challenges facing solar technology by leveraging knowledge from both the solar and semiconductor industries. They focused on developing a system-level approach that took into account each aspect of solar module production – from the cell to module assembly to the entire module itself. The team felt that if they balanced efficiency and cost they would be able to create a solar technology that would help shift solar from an alternative to a mainstream energy source.
With this long-term, ultimate goal in mind, Advent Solar created Ventura Technology. As the industry’s only comprehensive cell-to-module architectural approach, Ventura Solar Technology is designed to be scalable to multiple silicon types (such as multi-crystalline, mono-crystalline and upgraded metallurgical silicon) and amenable to highly automated semiconductor-like manufacturing. The architecture includes:
- Emitter-Wrap Through (EWT): A breakthrough cell-design that eliminates grid obstruction while still using low-cost solar-grade materials and fabrication processes. EWT cells have a clear advantage in terms of high efficiency with low-cost potential.
- Monolithic Module Assembly (MMA): A fully automated module assembly, applying proven, high volume, high precision semiconductor-style manufacturing techniques. Using robotic “pick and place” methods, each cell is perfectly arranged onto a monolithic integrated circuit backsheet. Novel bonding techniques form low resistance electrical contacts between the cells and backsheet with integrated circuit. The integrated backsheet is produced by very high-volume, low-cost roll-to-roll processing. By using planar processes and reducing the complexity of manufacturing processes, this approach results in highly repeatable, consistent module output with maximum yields.
Advent Solar provides Ventura Technology through a licensing model. Manufacturers licensing Ventura Technology intellectual property will be in a position to sustain efficiencies gained at the cellular level, as the cells are placed into modules. This unique process is designed to maximize module energy output with minimal interconnect resistance.
Conventional silicon-based PV architectures are rapidly approaching a point of diminishing return in garnering efficiency improvements, especially at a system level. Until recently, the learning curve of solar PV delivered around a 19% cost improvement (measured in cost per watt) with each doubling of industry production output. While this has been the case over the past three decades, steady improvement has become harder and harder to sustain. Conventional PV manufacturing approaches have emphasized cell efficiency and wafer thickness as primary drivers to address the cost per watt equation. However, gains in cell efficiency are invariably lost at the system level due to cumbersome manufacturing processes, while reductions in wafer thickness are becoming increasingly more difficult.
In order to continue the move toward grid parity, Advent Solar developed Ventura Technology. It is the industry’s only comprehensive system-level approach that eliminates efficiency bottlenecks throughout the module manufacturing chain. By eliminating grid lines on the front of the cell and module, the EWT cell maximizes light capture for energy conversion and also creates a visually appealing module surface. This also enables Advent Solar to reduce resistive losses between interconnects, which can account for 3% to 4%of efficiency losses using standard assembly processes. Products created with Ventura Solar Technology provide more energy output, and also address the aesthetic considerations for building integrated photovoltaic (BIPV) markets.
Advent Solar Ventura Technology revolutionizes photovoltaic product manufacturing and performance. Ventura Technology is based on a system-level architecture that optimizes output value at both the cell and module level. It combines unique EWT back-contact cell architecture with a highly automated, planar manufacturing process. This architecture was inspired by the semiconductor industry that excels in rapid technology evolution. In this way, cell and module performance characteristics are optimized together to deliver modules that have a higher output and are more reliable than conventional modules.
BENEFITS
Gains in cell and module level performance are becoming increasingly expensive to achieve. Conventional silicon PV manufacturers have a limited number of options for improving performance while simultaneously controlling costs. Since the silicon cost represents a dominant portion of the overall costs, most approaches focus on reducing wafer thickness as a primary avenue for reducing cost. By reducing wafer thickness, the utilization of silicon increases, thereby reducing costs. However, without an efficient module manufacturing process that accommodates thinner wafers, the cost reduction can be negated due to increased breakage and yield losses. As wafers get thinner, the cells become more susceptible to stress and bow resulting in yield fallout—thus increasing costs. In contrast, Advent Solar Ventura Technology allows for new cost improvements, such as:
- Emitter Wrap-Through (EWT) cell and Monolithic Module Assembly (MMA) approaches accommodate thinner wafers
- With the use of soft handling robotics, the highly automated manufacturing process uses “pick and place” tooling with precision, which reduces cell breakage
- Integrated module circuitry opens new opportunities for integration of value-added functions
Furthermore, Lux Research has estimated that Advent Solar’s conventional models will be approximately $2.90/W in cost through 2011 with a wafer thickness of around 170 μm, representing a 23% reduction in cost per watt with much of the change coming from reduction in materials costs and wafer thickness. The research firm also notes Advent Solar’s system handles the higher current density and physical strain more effectively than conventional approaches, and its ability to scale down to lower and lower silicon thicknesses will be a major advantage as the industry moves to cut silicon costs.
Supporting materials accompanying this awards package include:
Press release on the launch of Ventura Technology
Ventura Technology technical overview
Ventura Technology white paper
