Toshiba Enters Residential Solar Cell

System Market

Mar 2, 2010 12:57 Motonobu Kawai, Nikkei Electronics

Toshiba Corp will start selling residential solar cell systems using SunPower Corp’s monocrystalline silicon solar battery module April 1, 2010.

“We decided to enter the residential solar cell system market to promote our electric appliance and smart grid businesses,” the company said.

Toshiba plans to sell its solar cell systems together with its “SCiB” lithium-ion batteries and smart meters in the future.

All of the devices used for the residential solar cell system are purchased from outside companies, including the solar battery module, power conditioner (power conversion efficiency: 94%) and color display. Among them, SunPower’s solar battery module, “SPR-210N-WHT-J,” features a cell conversion efficiency as high as 21.5%, which Toshiba claims is the world’s highest level for commercialized solar cells.

The high conversion efficiency was realized by, for example, employing the monocrystalline silicon cell and the back-contact structure, in which electrodes are formed only on the back to increase the light-receiving area. The conversion efficiency as a module is 16.9%, and the maximum output is 210W.

The advantage of the back-contact structure is not only the enhancement of conversion efficiency. Because there is no electrode on the surface, electrodes do not glare when solar batteries are mounted. Some construction firms say that the electrodes on the surface of solar cells are a problem in designing, and this problem can be solved by employing the structure.

Toshiba’s employment of SunPower’s solar battery module will probably influence the business strategies of Japanese solar cell manufacturers. So far, Sanyo Electric Co Ltd’s HIT (heterojunction with intrinsic thin layer) solar cell has been known as a solar cell with a high conversion efficiency in Japan.

Sanyo and SunPower have been competing for the highest conversion efficiency at academic conferences. Also, as for the back-contact structure, Kyocera Corp is planning to release a product using polysilicon solar cells with the structure.

Sourced and published by Henry Sapiecha 4th March 2010

All-solid Li-polymer Battery Goes

Flexible, Slim

2010 21:39 Tetsuo Nozawa, Nikkei Electronics

Mie Industry Enterprise Support Center (MIESC) announced that it prototyped a “sheet-type all-solid polymer lithium storage battery” by using only printing processes.

The battery is safe, thin, flexible and large in area, MIESC said. It will be exhibited at the 1st Int’l Rechargeable Battery Expo, which will take place from March 3 to 5, 2010, in Tokyo.

The positive electrode layer, electrolyte layer and negative electrode layer of the lithium-ion battery are made by roll-to-roll processes. No separator is used between layers.

The positive electrode is made with LiFePO4 and a carbon complex while the negative electrode is made with Li4Ti5O12 and a complex of graphite, silicon, etc. A film made of a polymer material using a cross-linked polyethylene oxide is used for the electrolyte.

The polymer material is not in a gel state but in a solid state, and the battery does not use an organic electrolyte, which is flammable, ensuring high safety.

The A6-size lithium-ion battery is 450?m in thickness. Its initial capacity is 45mAh. When half of the capacity is discharged, its voltage is 1.8V. The discharge rate can be changed between 0.02C and 1.0C.

Existing all-solid lithium polymer storage batteries can hardly be used at a room temperature or below. But the new battery can be used even at a temperature from 0 to 25°C, MIESC said. The charge-discharge cycle is more than 100 and is still being evaluated, it said.

Sourced and published by Henry Sapiecha 4th March 2010

“Create the Future” Sustainable

Technologies Category Winner

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The 2008 NASA Tech Briefs “Create the Future Design Contest,” presented by SolidWorks, recognized innovation in product design in six categories: Consumer Products, Machinery & Equipment, Medical, Safety & Security, Sustainable Technologies, and Transportation. Here is the winner of the Sustainable Technologies category, along with the two honorable mentions.

Efficient Air Conditioner

Lindsay Meek
Perth, Australia

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altThis design improves the energy efficiency of a residential air conditioner by replacing the traditional reciprocating compressor (bore and stroke) with a higher efficiency permanent magnet motor coupled to a scroll compressor. Recent advances in permanent magnet motors used in modern hybrid car electric drives and wind turbine generation have seen the incorporation of strong NdFeB magnets into the rotor, which greatly improves the motor efficiency. The compressor motor is then driven by a compact IGBT inverter stage with a motor controller, so motor current consumption can be optimized at the different operating speeds.

The other improvement that can be made is to replace the traditional refrigerant expansion valve with a similar scroll expander turbine coupled to a second permanent magnet generator. The decompression of the refrigerant gas through the turbine on its way to the condenser allows some of the work used to compress the gas to be recovered and converted back into electrical energy. The generator is connected to a second compact IGBT inverter stage with a motor controller, and can be controlled in conjunction with the compressor motor controller to regulate the pressure and flow rate of the gas through the system.

The two inverters are connected together via a common, high-voltage DC bus, so the electrical energy recovered from the decompression state can be reused by the compression stage, improving the overall efficiency of the refrigeration cycle. Finally, an AC-DC rectifier power supply is needed to provide the main work energy for the DC bus to keep the cycle operating. The above improvements should lower the power consumption by at least 30%.

For more information, contact the inventor at lindsaymeek@hotmail.com

Sourced and published by Henry Sapiecha 8th Sept 2009

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Coupled Water Tower/Wind Turbine Controller
Andras Tanczos
Helsinki, Finland

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altA jointed water tower/wind turbine controller stores wind energy in the water towers of the drinking water network. At strong winds, the extra electrical energy generated by the wind turbine can be used to pump water into the water tower. When there is no wind, this energy can be released with a hydro-turbine, and the water goes back to the wells. The pump of the water tower and the hydro-turbine are used to control the water level in the reservoir. The electricity from the wind turbine is used for pumping the water or for supplying the electrical grid. The controller can also be installed on existing water towers and water tanks placed on top of buildings.

Sourced and published by Henry Sapiecha 8th Sept 2009

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Plastic Solar Cells For Electronic Devices

Currently silicon-based solar cells are flooding the market. Industry pundits can foresee a hopeful future for low-cost, flexible solar cells. If we can make solar devices other than silicon based materials then they can be used for all sorts of applications beyond just the traditional solar panels on house rooftops. It will be great if we can have solar cells for portable electronic devices too.

Luping Yu, Professor in Chemistry, and Yongye Liang, a Ph.D. student, both at the University of Chicago, and five co-authors are working to develop a new semiconducting material called PTB1, which converts sunlight into electricity. The University accredited the patent rights to the technology to Solarmer last September. The license covers numerous polymers under development in Yu’s laboratory, confirmed by Matthew Martin. He is a project manager at University of ChicagoTech, the University’s Office of Technology and Intellectual Property. A patent is pending.

Solarmer Energy Inc. is spreading its wings in this direction. They are willing to incorporate technology invented at the University of Chicago. The commercial-grade prototype will be completed at the end of this year. It will be eight square inches with a lifetime of three years. This plastic solar device will have the efficiency of eight percent. This eight percent efficiency will give an edge to the Solarmer Energy Inc. over its competitors. Dina Lozofsky, vice president of IP development and strategic alliances at Solarmer states, “Everyone in the industry is in the 5 percent to 6 percent range.”

The active layer of PTB1 is around 100 nanometers in thickness, and the width is nearly 1,000 atoms. If we want to produce a small amount of the PTB1 material it will take considerable amount of time, and the whole procedure will be multi-step process. But, still the biggest advantage of this technology lies in its simplicity. Several products are being synthesized in other laboratories in the U.S., but the competitive advantage lies in the steps of production too. Other devices need far more extensive engineering work for commercial viability. “We think that our system has potential,” Yu said. “The best system so far reported is 6.5%, but that’s not a single device. That’s two devices.”

Sourced and published by Henry Sapiecha 1st July 2009

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