I'm guessing the author of the article didn't do his homework and probably doesn't know the difference between energy and power.
If it's energy density, the figure is out of date -- modern 18650's are north of 250Wh/kg. If it's power density, the figure is just plain wrong, since that is equivalent to a 1C discharge rate. A power tool cell can easily deliver pulses of 30A; at 3.7V nominal less ~15mOhms of ESR, that translates into 96W in a 45g can -- 2kW/kg. -Ben On Apr 7, 2015, at 6:34 PM, Bill Dennis via EV <ev@lists.evdl.org> wrote: > Here's the URL to the article I quoted, plus the paragraph from the article > itself: > > http://www.engadget.com/2015/04/06/stanfords-battery-charges-in-one-minute/ > > " Unlike earlier aluminum batteries, which generally failed after only about > 100 recharge cycles, Stanford's prototype can cycle more than 7,500 times > without any capacity loss -- 7.5 times longer than your average li-ion. The > aluminum-ion cell isn't perfect (yet) as it can only produce about 2 volts, > far less than the 3.6V that lithium-ion an muster. Plus aluminum cells only > carry 40 watts of electricity per kilogram compared to lithium's 100 to 206 > W/kg power density." > > Bill > > -----Original Message----- > From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Cor van de Water > via EV > Sent: Tuesday, April 7, 2015 4:29 PM > To: Electric Vehicle Discussion List > Subject: Re: [EVDL] Aluminum battery from Stanford > > Actually, > the Nature article quotes 4 Amp per gram, so if a 2V cell weighs 1kg then it > could produce 4,000A or 8kW per kg > > The Capacity is quoted as 70mAh per gram, which is 140 Wh per kg (again, at > the expected 2V cell voltage). > > Note that all these numbers are the bare cell, so to compare with a CALB > 180Ah cell you'd either need to subtract the CALB's housing and connection > hardware weight, or estimate how much it would add to the Alu battery to > make a similar rugged and packaged end product. > By all accounts, it looks like very competitive to Li cells, but all > research takes many years before you can place an order for commercial > available product... > If it is really cheaper, better, safer, then we can see it break through > sooner. > Time will tell. > > Cor van de Water > Chief Scientist > Proxim Wireless > > office +1 408 383 7626 Skype: cor_van_de_water > XoIP +31 87 784 1130 private: cvandewater.info > www.proxim.com > > > This email message (including any attachments) contains confidential and > proprietary information of Proxim Wireless Corporation. If you received > this message in error, please delete it and notify the sender. Any > unauthorized use, disclosure, distribution, or copying of any part of this > message is prohibited. > > > -----Original Message----- > From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Bill Dennis via EV > Sent: Tuesday, April 07, 2015 2:59 PM > To: 'Electric Vehicle Discussion List' > Subject: Re: [EVDL] Aluminum battery from Stanford > > Their current version of the battery has only 40 watts of electricity per > kilogram compared to lithium's 100 to 206 W/kg power density--so you'd need > more of them to get the same power. That might get better as they improve > the cells, of course. > > Bill > > -----Original Message----- > From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Ben Goren via EV > Sent: Tuesday, April 7, 2015 2:11 PM > To: Electric Vehicle Discussion List > Subject: [EVDL] Aluminum battery from Stanford offers safe alternative to > conventional batteries > > Does anybody know any more about this research? > > http://news.stanford.edu/news/2015/march/aluminum-ion-battery-033115.html > > Aluminum anode; graphite cathode. Unspecified salt for the electrolyte. > > It's only about two volts. The rest of the specs are vague...nothing at all > about capacity. They claim super-fast charging times without indicating how > much energy the batteries actually take on. They claim several thousand > charge cycles. No mention of energy density per mass. The prototype is > bendable, in what looks for all the world like a mylar ziploc bag. They show > the battery being drilled into with minimal ill effect. > > I find it intriguing to consider for an electric vehicle...because a > super-fast charging time, if real, would similarly imply a super-fast > discharge rate. It gives the appearance of being technology within the reach > of an hobbyist to manufacture. Form factor is obviously quite literally > flexible. > > In other words...I can almost imagine building a battery like this, myself, > at home, to put into a car conversion. Or, if it's too heavy for vehicles, > then to stick in the closet to pair with the solar PV array. > > Any experts out there have any good water to throw over me? > > b& > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA > (http://groups.yahoo.com/group/NEDRA) > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA > (http://groups.yahoo.com/group/NEDRA) > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA > (http://groups.yahoo.com/group/NEDRA) > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA > (http://groups.yahoo.com/group/NEDRA) > _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
