It is interesting to contemplate the driving need for these batteries in an aircraft setting.
In a large commercial airliner, especially a brand new one such as the B-787 Dreamliner, the need is purely a mass savings, which translates into improved fuel economy if one carries the fuel economy calculation to enough places to the right of the decimal point. But this is the same false economy as a bicycle salesman trying to sell an average rider on some fancy carbon composition graphite frame because it knocks a couple pounds off the bicycle mass. That is all well and good if the rider's body mass is optimized as would be the case for a professional racer, but for the average rider, it would be much more economical to lose five pounds than to go from steel or aluminum to carbon to lose two pounds. This is of course the case with the flying public, at least on this side of the Pond. Not saying that there is any push to cause weight loss in the flying public, just that it doesn't make sense to shave ounces here and there in the airframe while the flying public is packing on pounds here, there, and everywhere. In contrast, my first exposure to an aircraft use for a lithium ion battery was a desire to provide for automatic weapon use on a US Army helicopter in the event the engines failed and there was no AC power, only dc from a battery-supported bus. This was a response to the "Blackhawk Down" scenario and the gun was converted to run off dc instead of ac, plus the gun drew more current than conventional batteries could source for the required time period, and there was no room in the existing airframe for more conventional batteries. A lithium ion battery was a form, fit and function replacement for the existing batteries, with a higher amp-hour rating, and also lower output impedance to be able to source the transient current necessary to get the gun going. Ken Javor Phone: (256) 650-5261 > From: John Woodgate <[email protected]> > Date: Sun, 10 Mar 2013 17:10:04 +0000 > To: <[email protected]> > Subject: Re: Immunity and emissions below 150 kHz and lithium batteries > > In message <cd622710.3e269%[email protected]>, dated Sun, 10 > Mar 2013, Ken Javor <[email protected]> writes: > >> In an aircraft lithium ion battery that can source hundreds of amps >> there is lots of parallel! > > I'm giving up flying, then. > -- > OOO - Own Opinions Only. See www.jmwa.demon.co.uk > SHOCK HORROR! Dinosaur-like DNA found in chicken and turkey meals > John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK > > - > ---------------------------------------------------------------- > This message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. To post a message to the list, send your e-mail to > <[email protected]> > > All emc-pstc postings are archived and searchable on the web at: > http://www.ieee-pses.org/emc-pstc.html > > Attachments are not permitted but the IEEE PSES Online Communities site at > http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used > formats), large files, etc. > > Website: http://www.ieee-pses.org/ > Instructions: http://listserv.ieee.org/request/user-guide.html > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas <[email protected]> > Mike Cantwell <[email protected]> > > For policy questions, send mail to: > Jim Bacher: <[email protected]> > David Heald: <[email protected]> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
