From ecars-now-global-newsletter at ecars-now.org Fri Jul 9 02:00:30 2010 From: ecars-now-global-newsletter at ecars-now.org (eCars-now Global newsletter) Date: Thu, 8 Jul 2010 16:00:30 -0700 (PDT) Subject: [Ecars-now-global-newsletter] BMW Leads in New Carbon Fiber Technology Message-ID: BMW?s New Process to Use Carbon Fiber for Cars Another Blessing from Nanotechnology! ?Carbon fiber is an expensive alternative to steel or aluminum, but besides being extremely strong it is also very light. It is found in high-performance parts, such as aircraft wings, bits of super- cars, and the frames of pricey mountain bikes. But if work by Germany?s BMW proves successful, it could also become the material of choice to mass-produce electric cars. [...and aircraft wings, bits of super-cars, and the frames of pricey mountain bikes. ?Vicar] The Bavarian carmaker plans to launch a new plug-in electric car in 2013. It will be one of the first designed from scratch to use an electric motor rather than being converted from an existing model and to use no steel. The Megacity will be built as two modules: an aluminum chassis will contain the electric drive-system and battery, and a body made almost entirely of carbon fiber will be fitted onto it. Carbon fiber is 30% lighter than aluminum and 50% lighter than steel. The fibers are extremely tear-resistant. When woven into a lattice structure and impregnated with resin they can produce a part that is stronger than steel. Its production line starts with a so-called precursor: a fiber spun from a polymer. This is carbonized by heating it in multiple stages to leave individual carbon fibers just seven microns (0.007 millimeters) thick. Around 50,000 of these fibers are bundled together into a yarn which is then made into a fabric. This can be cut and handled like a textile. Strips of fabric are then overlaid to align their fibers in such a way to maximize their load-bearing characteristics as required and enable mass production of the parts! BMW uses molds, heat and pressure to produce contours in the fabric. Resin is then injected into the molds to bond the fibers together. How the resin flows through the fibers is crucial; it has to be done quickly and leave no area untreated before it starts to cure. A release agent in the resin migrates to the surface to prevent the component sticking in the mold. The whole process handled by robots is completed in minutes. Another advantage of a carbon-fiber body is that it will not corrode. So, apart from replacing batteries in about ten years, electric cars could last for several decades (electric motors need little servicing). This benefit is not appreciated by car manufacturers! Full article: http://www.economist.com/node/16537608 -------------- next part -------------- An HTML attachment was scrubbed... URL: From ecars-now-global-newsletter at ecars-now.org Mon Jul 12 15:56:28 2010 From: ecars-now-global-newsletter at ecars-now.org (eCars-now Global newsletter) Date: Mon, 12 Jul 2010 05:56:28 -0700 (PDT) Subject: [Ecars-now-global-newsletter] Tips to Extend Battery Life Message-ID: Three Tips to Extend EV Battery Life (1) Embrace the Middle Ground In most cases drivers won?t need to ?concern themselves regarding the best state of charge in which to leave their battery, but keeping a battery fully charged for an extended period of time will have cause a shorter life than batteries that are held at a lower state of charge. The first generation electric vehicles rolling out in the next couple years will have batteries limited from discharging below 50 percent. These limits on ?deep discharging? are meant to ?maintain battery life.? The bottom line is that a moderate state-of-charge, in the range of 40-70 percent of capacity, is generally the best state of charge to leave a battery before leaving [it] unused for an extended period of time. (2) Mind the Charge Day to day, the recommendation is to? charge frequently, even if it is only a partial charge, because lithium-ion batteries generally last longer when they are ?cycled? (charged and discharged) more shallowly rather than cycled fully from 100 percent charge to zero. In addition to how often you charge and how fully you let a battery discharge, fast charging a battery can also affect the rate at which it loses capacity. A 480-volt quick charge (80 percent charge in about 30 minutes) for the LEAF s expected to accelerate capacity loss compared to 220-volt charging (full charge in about 8 hours). So if quick charging is the primary method of recharging for a given vehicle, it will bring the capacity loss closer to 70 percent after 10 years. (3) Keep It Cool A key practice to max battery life ? whether in an electric car or a laptop ? is to keep it cool. One simple thing that a driver can do, is to park the vehicle in the shade. Sunlight can create significant increases in the cabin temperature in a vehicle, and over time the repeated exposure to high temperatures will reduce the battery?s lifespan. While moderately cool temperatures can help to extend battery life, very cold temperatures can reduce the range. Former GM Vice Chairman Bob Lutz noted earlier this year that his Volt only got 28 miles when he drove a Volt for a weekend in Detroit this winter, rather than the 40 miles that GM says will be typical. ?The range can vary on any given day depending on temperature, terrain, driving conditions and so forth ? especially temperature,? Lutz explained. ?The distance you can go in any electric vehicle varies hugely with the outside temperature.? Full, Unedited Article: http://earth2tech.com/2010/07/11/3-steps-to-max-out-battery-life-for-electric-cars/ -------------- next part -------------- An HTML attachment was scrubbed... URL: