Redox shuttle provides highest overcharge protection for certain cathodes

 

Scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory have patented an extremely stable, 4-Volt redox shuttle molecule that provides overcharge protection for lithium-ion batteries containing lithium–iron-phosphate based cathodes across hundreds of charging cycles.

Overcharge is a major safety concern for Li-ion batteries because it could cause thermal runaway, a concern for large batteries – such as those used for transportation and storage applications – because they contain a large amount of active material.

“When a battery pack is being charged, each cell in the pack may have varying levels of charge,” said Argonne materials scientist Khalil Amine, who leads the research group that developed the shuttle. “Overcharge generally occurs when a current is forced through a battery and the charge that is delivered exceeds the charge-storing capacity of the battery, which can damage the entire battery.”

Modern, well-designed batteries prevent overcharge from occurring through use of external battery monitoring and control systems that function both at the cell and battery level. This new material offers a tool for addressing some of the concerns associated with overcharge using an approach that functions inside each cell.

“The new redox shuttle, known as 2,5-di-tert-butyl-1,4-bis(2-methoxyethoxy)benzene or DBBB, works by halting the charging process of individual cells as they come to a full state of charge,” Amine said. “Being able to discontinue the charging process on a cell-by-cell basis protects the entire battery pack by preventing individual cells from overcharging.”

DBBB, which dissolves in the electrolyte, works by moving back and forth from the anode and cathode in place of the Li-ion, Amine explained. The shuttle technology achieved up to 300 cycled overcharges in the lab. The shuttle is undergoing validation test by industry, and the results to date are very encouraging, he said.

Researchers in Argonne’s Advanced Battery Materials Synthesis and Manufacturing Research & Development Program have already scaled up production of DBBB to 1.5 kilograms from the sub-gram amounts Amine’s group required for bench-scale research and development. The larger amount of the redox shuttle material is needed by companies that want to test the material for possible commercialization. The stability and repeated long-term overcharge cycling capability of this new shuttle molecule was demonstrated by Amine and his Argonne colleagues Zhengcheng Zhang, Lu Zhang and Wei Weng.

The redox shuttle is part of a suite of advanced battery materials developed by scientists at Argonne. The lab’s Advanced Battery Materials Synthesis and Manufacturing R&D Program focuses on scalable-process R&D to produce advanced battery materials in sufficient quantity for industrial testing. This work is intended to support domestic battery manufacturing and to enable the transition of new materials and technology to the market.
Argonne
www.Anl.gov

What Works in Aerospace Can Work in Wind

How are wind turbine materials changing?

One recent composite material provides a way to treat and modify the surface of fiberglass to create a chemical bond between the glass and a resin matrix. This material substitutes standard fiberglass with short micro-fibers.

The manufacturer says its liquid composites can be poured, pumped, or sprayed, and after curing can be drilled, tapped, and CNC machined. In addition, the material’s predictable properties allow calculating strength along with the design of more complex shaped components.

The most used metal in a wind turbine is steel in the tower and other components. But a few more recent material ideas deserve mention. For instance, one solution to the climbing cost of all copper wire is in copper- clad steel. It is said to be reliable, cost effective, and can provide the wind industry with a smarter alternative to copper-based grounding systems. The financial crisis has altered the trajectory of wind-farm projects by tightening developers’ budgets with a need to control costs, an increasing priority even as the industry expands.

A good grounding system plays a critical role guarding against catastrophic damage to blades, electronics, transformers, nacelles, and collector systems out to substations.

Until recently, copper has been the predominant material in wire and cable used to grounding of electrical systems. But the cost of copper fluctuates substantially. This is bad news for wind-farm developers, and electrical and construction contractors who are under increasing pressure to control costs.

Given the cost sensitivity of any wind-farm project, the idea of burying a precious metal (copper) underground makes little economic sense when less expensive, alternatives are readily available. Copper-clad steel has been around for decades and is a practical option to consider in grounding applications. It offers an alternative to copper by combining the strength of steel with the conductivity of copper through a cladding that delivers comparable performance.

Spanish turbine OEM opens materials tech center in Singapore

A Spain-based wind turbine OEM has opened a technology centre in Singapore to focus on advanced materials research. Gamesa’s new laboratory begins its work with three important research projects, conducted jointly with the Nanyang Technological University, the National University of Singapore, and the Agency for Science, Technology and Research (A*STAR). Gamesa expects the tech lab to employ more than 30 engineers by 2014.

The partnership with the Nanyang Technological University lets Gamesa conduct research projects on wind turbine blade coatings and methods for incorporating the materials into the company’s manufacturing systems. Along with the National University of Singapore, the company will study methods for monitoring composite materials using embedded sensors and will assess their industrial applications. Meanwhile, in conjunction with the Institute of Materials Research and Engineering (IMRE), a research institute of A*STAR, Gamesa will gauge the performance of turbine blades’ carbon fiber polymers after using nano-reinforcements to strengthen them. Gamesa will explore R&D in manufacturing with the Singapore Institute of Manufacturing Technology (SIMTech), a research institute of A*STAR.

“We are determined to offer the best solutions for generating wind energy,” says Gamesa Chairman Jorge Calvet at the facility’s opening ceremony. “Our alliance with these institutions will help us to remain at the forefront of advanced materials research, a field in which our new partners are likewise a global benchmark.”

According to Gamesa Chief Technology Officer José Antonio Malumbres, “These agreements offer potential for improving the reliability, efficiency, and availability of our wind turbines and, by extension, their cost of energy. We have found the ideal partners for this journey, and together we will remain at the cutting edge of the industry”.

Mr Yeoh Keat Chuan, Assistant Managing Director of the Singapore Economic Development Board, said “We are pleased that Gamesa has decided to establish its advanced materials R&D centre in Singapore. This reflects well on Singapore’s strengths as a location for wind energy research, namely our strong R&D infrastructure, skilled cosmopolitan workforce and favourable intellectual property protection. Gamesa can also leverage complementary capabilities from industry clusters such as aerospace and offshore marine engineering, to accelerate the commercialisation of new technologies and applications.”

Added Mr Lim Chuan Poh, Chairman of A*STAR,“By anchoring R&D activities here, Gamesa will have numerous opportunities to engage in many meaningful and impactful research collaborations with A*STAR, NUS, and NTU. Singapore has invested steadily in and developed systematically the R&D capabilities and infrastructure in the public sector over the last 20 years and we welcome the business sector to fully leverage on these capabilities. This is part of Singapore’s strategy to become a global R&D hub and Asia’s Innovation Capital”.

“A*STAR through its research institutes will contribute integrated and relevant expertise in clean energy technology to participate actively in Gamesa’s future growth. For example, our expertise in nanocomposite and polymer materials can be applied to strengthen the turbine blades and provide robust coatings to protect structures from the ravages of harsh environments”, said Prof Andy Hor, Executive Director of IMRE.

The new tech lab in Singapore is part of Gamesa’s strategy for becoming a global standard-bearer in lowering turbines’ cost of energy (COE), based on the reliability, efficiency and availability of its current and future catalogue of products and services.

Gamesa plans to cut its customers’ cost of energy by 20% through 2013 and by 30% through 2015 by introducing new products (five onshore and offshore turbine systems) and developing new applied technologies, maintenance improvements, etc.

The company’s commitment to R&D calls for boosting engineering hours (to 1.5 million hours per year) and doubling its number of R&D staff through 2013.

Gamesa

http://www.windpowerengineering.com/directory/21266/gamesa/

Blade-repair materials widen repair’s weather window

A novel approach to blade repair addresses several issues that have prevented more effective and expedient maintenance programs. The Renuvo blade-repair system is said to provide a solution to problems of production, transportation, and in-field work.

Creating a wider weather window for repair work comes from a handling and working-temperature range that starts at +5°C. The product range has transformed the condition for repair by using UV light from the Renuvo Lamp to cure materials in minutes.

More traditional wet laminating systems generate waste, have the potential for error in dispensing and mixing, along with the requirement for multiple products to match the blade design. Renuvo eliminates the problems and lets the operator take control over quality, backed by the reassurance of the GL certified (pending) products and process guide.

Composites One and 3M Renewable Energy Division Form Alliance

Arlington Heights, IL – Composites One announced that it has formed an important alliance with the 3M’s Renewable Energy Division. This agreement will allow Composites One and 3M to continue to penetrate the emerging wind energy industry with products geared specifically toward wind turbine manufacturers. It will also further enhance the partnership Composites One already shares with 3M.

3M Renewable Energy will offer to the market a mix of sophisticated product solutions, including a variety of tapes, adhesives, and fillers that enhance reliability, improve performance, and provide protection against weathering and harsh environments. Customers will also benefit from direct interaction with both 3M and Composites One as they work together to develop custom product solutions based on their material and manufacturing needs.

In today’s wind industry, 3M already has a solid reputation by offering multiple solutions used to enhance manufacturing efficiency and safety. The 3M Renewable Energy product line will only solidify that reputation as a leader in product development for the wind energy market.

Composites One
www.compositesone.com

Industrial “kitchen” Cooks up New Materials

Industrial designers and engineers face the challenge of new applications that require paying attention to material’s weight, strength, and cost. The rapid development of alternative energy and other industrial markets is driving a new demand for technology creators to construct and design these applications. So, a recently formed group at Cytec Engineered Materials, Tempe, Ariz., addresses the growing need for advanced industrial materials. This new group, led by company VP Steve Stone, uses the technologies in the Cytec portfolio across multiple industrial markets, such as wind, alternative energy, construction, marine, and high performance automotive.
“Engineering needs and technology are bridging the aerospace and industrial segments,” says Stone. “There is an increased use of composites and adhesives in both markets and increasing demands for technology and higher performance.” The firm’s product and service portfolio is comprised of company prepregs, resin infusion, adhesives, and gel coats and top coats focused on meeting the needs and escalating performance requirements of the industrial sector.

A material for large parts, without an autoclave

Cycom 5320 is a toughened epoxy resin prepreg system from Cytec Engineered Materials, Woodland Park, NJ. It is intended for out-of-autoclave (OOA) manufacturing yet provides the performance of an autoclaved material with the benefit of lower processing costs and manufacturing flexibility. The material allows designing large primary structures, without the costs and size limitations of an autoclave. Only a properly sized oven is needed.

Low temperature curing makes the material well suited for many structural and aerospace applications. Low-cost tooling and OOA curing offers the advantage of using one material for prototype and high-rate production.

Cycom 5320 offers the mechanical performance equivalent to 350F autoclave-cured, toughened epoxy prepreg systems. The material gives users flexibility to vary the cure cycle from 200F for 8hr to 250F for 2hr (followed by a 350F two-hour post cure). This flexibility provides a wide processing window to provide maximized mechanical properties.

The company lists these additional features and benefits for the material:

• Developed for primary structures
• Excellent hot and wet properties
• Low void content
• Suitable for complex parts
• Low cost tooling
• Flexible cure cycles
• Mechanical properties equivalent to standard 350F or 177C, autoclave-cured epoxy after freestanding post cure