AeroElectric-List Digest Archive

Mon 05/13/13


Total Messages Posted: 2



Today's Message Index:
----------------------
 
     1. 09:58 AM - Re: Lithium batteries for OBAM aircraft (Richard Girard)
     2. 11:27 AM - Re: Re: Crowbar OV Module (jan)
 
 
 


Message 1


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    Time: 09:58:57 AM PST US
    Subject: Re: Lithium batteries for OBAM aircraft
    From: Richard Girard <aslsa.rng@gmail.com>
    David, " Disconnect the charger and measure the open circuit voltage a few times a day for two weeks." This would suggest to me that this technology, at least in airplanes, is completely immature. I don't know about you, but when I buy an SLA battery I ask the sales person if it's charged. If the answer is affirmative it goes in the airplane and VROOM! Just sayin'. Rick Girard do not archive On Sun, May 12, 2013 at 8:51 PM, David Josephson <dlj04@josephson.com>wrote: > dlj04@josephson.com> > > I attended the Electric Aircraft Symposium put on by CAFE a few weeks ago. > One of the speakers was Dr Eric Darcy of the NASA Johnson Spaceflight > Center in Houston, on "Mitigating Catastrophic Failures with Li-ion > Batteries." He has the task of figuring out how to change out the batteries > in the International Space Station, and for now they are planning to use > the same GS-Yuasa LVP lithium cobalt cells that are in the Boeing 787. As > you might imagine, he's not quite ready to give the green light for using > them in the Space Station. > > We learned a lot about keeping lithium batteries from doing bad things, > and about some things that amateurs can do to test cells for likely > problems. All variants (LiPo, LiFe, Li-poly etc.) have the same thermal > runaway problem that seems to have been the failure mechanism in the > incidents to date, some just take more abuse to start it. Besides that, the > lithium cobalt chemistry (used in the 787, Tesla cars, laptops and many > other applications) uses a flammable electrolyte that isn't used in the > lithium/manganese or lithium/iron used in some others. He thought they were > all just as dangerous, though, and were subject to all of the same problems. > > Once the cell develops a short, all of its energy gets released as heat, > potentially causing the neighboring cells to do the same. Of course the > known limits for charge voltage and discharge current must be followed. You > also need to avoid mechanical damage that could cause a short between the > plates of the cell (drive a nail through and they will explode.) But the > famous failures so far have probably not been due to any of those things. > Dr. Darcy was clear to point out that he didn't know what happened with the > 787 batteries but discussed failures that he had seen in many other cell > types, both prismatic and "jelly roll." Two main events can happen: a small > inclusion like a tiny snip of metal or dirt can be trapped in the separator > between the battery plates that ultimately starts forming a current path > between them, or the edges of the plates which are supposed to be > overlapped by insulating material can come close to touching if they are > misaligned, causing the same sort of contact. > > Many of these cell failures can be caught long before the cell melts down, > because each of these almost-short-circuits usually causes some discharge > before the full battery current can flow. Darcy suggested two tests that > anyone could do. One is when receiving a lot of cells, that have been > partially charged and then shipped a long distance, measure the open > circuit voltage of each one. They should all be very close to each other, > like within 1%. The other test is to charge each cell to full capacity and > then discharge to 10%, say 3.25 volts. Disconnect the charger and measure > the open circuit voltage a few times a day for two weeks. Good cells will > climb at a uniform rate back to their original voltage, suspect cells will > have a very different curve, either much slower or much faster (typically > followed by a droop). At the end of two weeks, trust the cells that are all > clustered with the same open circuit voltage. > > I would imagine that the folks packaging cells into aircraft batteries do > some of this testing, but it's good to know that some simple methods can be > used to check cells beforehand. > > -- > David Josephson > > -- Zulu Delta Mk IIIC Thanks, Homer GBYM It isn't necessary to have relatives in Kansas City in order to be unhappy. - Groucho Marx


    Message 2


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    Time: 11:27:46 AM PST US
    From: jan <jan@CLAVER.DEMON.CO.UK>
    Subject: Re: Crowbar OV Module
    Bob, Done a bit of digging on this .. First Valence is still in Chapter 11. Yes they have supplied some battery modules to Alliant - The US aerospace military contractor. If that ever became of anything 'large scale' I am not sure .. if it ever did . it may not have been very profitable .. i.e. Chapter 11 :-) Aliant in Italy have nothing to do with Valence - What Aliant looks to have done is to do the same as Valence did from a integration point - Take small Li-phosphate cells - and integrate them to look like a 'normal battery' .. and include some form of BMS. What was great with Valence was that they based the form factor on your normal 12V 'golf cart' size battery - but it had 3 times the energy. Each battery would like together and you had a master MBS that would talk to all the battery modules and you would get all sort of interesting info over CAN. >From what I can see - Aliant in Italy have focused on single battery only (i.e. not high voltage application - with Valence you could easily string the battery together to give you 400VDC) ... What Aliant is saying about starting from a BMS is just sales blurb .. no one that makes any Li-ion battery will do so unless they have some form of BMS. The question is how good and sophisticated the MBS is. I would not be surprised if Aliant are using the same cells as Valence - but that is pure guesswork - The cells are made in China by Tianjin Lishen Battery. If I was to stick a Li-ion battery in a plane I would like to know a lot more about the BMS and how it interact with the cells. _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of jan Sent: 12 May 2013 15:15 Subject: RE: AeroElectric-List: Re: Crowbar OV Module Bob, I will make a few phone calls next week and see what I can find out... Jan _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: 12 May 2013 14:43 Subject: RE: AeroElectric-List: Re: Crowbar OV Module At 03:01 AM 5/12/2013, you wrote: I know Valence very well. Been using them for a few years in other applications - They ran out of money some time ago. Looks like they are now doing work with this Aliant company .. Valence had a good technology and a good BMS system - Also the Iron Phosphate technology is pretty safe - Not as energy dense or as powerful as Cobalt . To not damage the cells - over voltage under voltage and temperatures all have to be watched and maintained to not damage the cell. Are you saying there IS a cooperation between Aliant the battery guys and Alliant/Valence the aerospace/ military guys? Bob . . . http://www.matronics.com/Navigator?AeroElectric-List http://forums.matronics.com http://www.matronics.com/contribution <html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:st1="urn:schemas-microsoft-com:office:smarttags" xmlns="http://www.w3.org/TR/REC-html40"> <head> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii"> <meta name=Generator content="Microsoft Word 11 (filtered medium)"> <!--[if !mso]> <style> v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} </style> <![endif]--><o:SmartTagType namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="country-region"/> <o:SmartTagType namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="City"/> <o:SmartTagType namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="place"/> <o:SmartTagType namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="PersonName"/> <!--[if !mso]> <style> st1\:*{behavior:url(#default#ieooui) } </style> <![endif]--> <style> <!-- /* Font Definitions */ @font-face {font-family:Wingdings; panose-1:5 0 0 0 0 0 0 0 0 0;} @font-face {font-family:Tahoma; panose-1:2 11 6 4 3 5 4 4 2 4;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {margin:0cm; margin-bottom:.0001pt; font-size:12.0pt; font-family:"Times New Roman";} a:link, span.MsoHyperlink {color:blue; text-decoration:underline;} a:visited, span.MsoHyperlinkFollowed {color:blue; text-decoration:underline;} p {mso-margin-top-alt:auto; margin-right:0cm; mso-margin-bottom-alt:auto; margin-left:0cm; font-size:12.0pt; font-family:"Times New Roman";} pre {margin:0cm; margin-bottom:.0001pt; font-size:10.0pt; font-family:"Courier New";} span.EmailStyle19 {mso-style-type:personal; font-family:Arial; color:navy;} span.EmailStyle20 {mso-style-type:personal-reply; font-family:Arial; color:navy;} @page Section1 {size:612.0pt 792.0pt; margin:72.0pt 90.0pt 72.0pt 90.0pt;} div.Section1 {page:Section1;} --> </style> </head> <body lang=EN-US link=blue vlink=blue> <div class=Section1> <p class=MsoNormal><st1:PersonName w:st="on"><font size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;color:navy'>Bob</span></font ></st1:PersonName><font size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial; color:navy'>,<o:p></o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'>Done a bit of digging on this ..<o:p></o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'>First <st1:City w:st="on"><st1:place w:st="on">Valence</st1:place></st1:City> is still in Chapter 11. Yes they have supplied some battery modules to Alliant &#8211; The US aerospace military contractor.&nbsp; If that ever became of anything &#8216;large scale&#8217; I am not sure .. if it ever did . it may not have been very profitable .. i.e. Chapter 11&nbsp; </span></font><font size=2 color=navy face=Wingdings><span style='font-size:10.0pt;font-family: Wingdings;color:navy'>J</span></font><font size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;color:navy'><o:p></o:p></spa n></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'>Aliant in &nbsp;Italy have nothing to do with Valence &#8211; What Aliant looks to have done is to do the same as Valence did from a integration point &#8211; Take small Li-phosphate cells &#8211; and integrate them to look like a &#8216;normal battery&#8217; .. and include some form of BMS.<o:p></o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'>What was great with <st1:City w:st="on"><st1:place w:st="on">Valence</st1:place></st1:City> was that they based the form factor on your normal 12V &#8216;golf cart&#8217; size &nbsp;battery &#8211; but it had 3 times the energy. Each battery would like together and you had a master MBS that would talk to all the battery modules and you would get all sort of interesting info over <st1:country-region w:st="on"><st1:place w:st="on">CAN.</st1:place></st1:country-region> <o:p></o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'>From what I can see &#8211; Aliant in <st1:country-region w:st="on">Italy</st1:country-region> have focused on single battery only (i.e. not high voltage application &#8211; with <st1:City w:st="on"><st1:place w:st="on">Valence</st1:place></st1:City> you could easily string the battery together to give you 400VDC) &#8230;<o:p></o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'>What Aliant is saying about starting from a BMS is just sales blurb .. no one that makes any Li-ion battery will do so unless they have some form of BMS. The question is how good and sophisticated the MBS is.<o:p></o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'>I would not be surprised if Aliant are using the same cells as <st1:City w:st="on">Valence</st1:City> &#8211; but that is pure guesswork &#8211; The cells are made in <st1:place w:st="on"><st1:country-region w:st="on">China</st1:country-region></st1:place> by Tianjin Lishen Battery. <o:p></o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'>If I was to stick a Li-ion battery in a plane I would like to know a lot more about the BMS and how it interact with the cells.<o:p></o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p> <div> <div class=MsoNormal align=center style='text-align:center'><font size=3 face="Times New Roman"><span style='font-size:12.0pt'> <hr size=2 width="100%" align=center tabindex=-1> </span></font></div> <p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt; font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] <b><span style='font-weight:bold'>On Behalf Of </span></b>jan<br> <b><span style='font-weight:bold'>Sent:</span></b> 12 May 2013 15:15<br> <b><span style='font-weight:bold'>To:</span></b> <st1:PersonName w:st="on">aeroelectric-list@matronics.com</st1:PersonName><br> <b><span style='font-weight:bold'>Subject:</span></b> RE: AeroElectric-List: Re: Crowbar OV Module</span></font><o:p></o:p></p> </div> <p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size: 12.0pt'><o:p>&nbsp;</o:p></span></font></p> <p class=MsoNormal><st1:PersonName w:st="on"><font size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;color:navy'>Bob</span></font ></st1:PersonName><font size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial; color:navy'>,<o:p></o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'>I will make a few phone calls next week and see what I can find out&#8230;<o:p></o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'>Jan<o:p></o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'><o:p>&nbsp;</o:p></span></font></p> <div> <div class=MsoNormal align=center style='text-align:center'><font size=3 face="Times New Roman"><span style='font-size:12.0pt'> <hr size=2 width="100%" align=center tabindex=-1> </span></font></div> <p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt; font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] <b><span style='font-weight:bold'>On Behalf Of </span></b>Robert L. Nuckolls, III<br> <b><span style='font-weight:bold'>Sent:</span></b> 12 May 2013 14:43<br> <b><span style='font-weight:bold'>To:</span></b> <st1:PersonName w:st="on">aeroelectric-list@matronics.com</st1:PersonName><br> <b><span style='font-weight:bold'>Subject:</span></b> RE: AeroElectric-List: Re: Crowbar OV Module</span></font><o:p></o:p></p> </div> <p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size: 12.0pt'><o:p>&nbsp;</o:p></span></font></p> <p class=MsoNormal style='margin-bottom:12.0pt'><font size=3 face="Times New Roman"><span style='font-size:12.0pt'>At 03:01 AM 5/12/2013, you wrote:<o:p></o:p></span></font></p> <p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size: 10.0pt;font-family:Arial;color:navy'>I know <st1:place w:st="on"><st1:City w:st="on">Valence</st1:City></st1:place> very well. Been using them for a few years in other applications &#8211; They ran out of money some time ago. Looks like they are now doing work with this Aliant company ..&nbsp; <st1:place w:st="on"><st1:City w:st="on">Valence</st1:City></st1:place> had a good technology and a good BMS system &#8211; Also the Iron Phosphate technology is pretty safe &#8211; Not as energy dense or as powerful as Cobalt&nbsp; .<br> &nbsp;<br> To not damage the cells &#8211; over voltage under voltage and temperatu res all have to be watched and maintained to not damage the cell.<br> &nbsp;<br> &nbsp;<br> &nbsp;</span></font><o:p></o:p></p> <p class=MsoNormal style='margin-bottom:12.0pt'><font size=3 face="Times New Roman"><span style='font-size:12.0pt'><br> &nbsp; Are you saying there IS a cooperation between Aliant<br> &nbsp; the battery guys and Alliant/Valence the aerospace/<br> &nbsp; military guys?<br> <br> <br> <o:p></o:p></span></font></p> <p></x-sigsep><font size=3 face="Times New Roman"><span style='font-size:12.0pt'><x-sigsep>&nbsp; <st1:PersonName w:st="on">Bob</st1:PersonName> . . . <o:p></o:p></span></font></p> <pre><b><font size=2 face="Courier New"><span style='font-size:10.0pt; font-weight:bold'><o:p>&nbsp;</o:p></span></font></b></pre><pre><b><font size=2 face="Courier New"><span style='font-size:10.0pt;font-weight:bold'><o:p>&nbsp;</o:p></span></fo nt></b></pre><pre><b><font size=2 face="Courier New"><span style='font-size:10.0pt;font-weight:bold'><o:p>&nbsp;</o:p></span></fo nt></b></pre><pre><b><font size=2 face="Courier New"><span style='font-size:10.0pt;font-weight:bold'></span><span List Features Navigator to browse<o:p><span t><span href="http://www.matronics.com/Navigator?AeroElectric-List">http://www .matronics.com/Navigator?AeroElectric-List<o:p></o:p></span></font></b> </pre></span><pre><b><font size=2 face="Courier New"><span t><span style='font-size:10.0pt;font-weight: bold'><o:p>&nbsp;</o:p></span></font></b></pre><pre><b><font size=2 face="Courier New"><span style='font-size:10.0pt;font-weight:bold'></span><span also available via the Web Forums!<o:p><span t><span href="http://forums.matronics.com">http://forums.matronics.com<o:p></o :p></span></font></b></pre></span><pre><b><font size=2 face="Courier New"><span t><span style='font-size:10.0pt;font-weight: bold'><o:p>&nbsp;</o:p></span></font></b></pre><pre><b><font size=2 face="Courier New"><span style='font-size:10.0pt;font-weight:bold'></span><span your generous support!<o:p><span href="http://www.matronics.com/contribution">http://www.matronics.com/ contribution<o:p></o:p></span></font></b></pre></span><pre><b><font size=2 face="Courier New"><span style='font-size:10.0pt;font-weight:bold'><o:p>&nbsp;</o:p></span></fo nt></b></pre><pre><b><font size=2 face="Courier New"><span style='font-size:10.0pt;font-weight:bold'><o:p>&nbsp;</o:p></span></fo nt></b></pre></div> </span></span></span></span> <pre><b><font size=2 color="#000000" face="courier new,courier"> </b></font></pre></body></html>




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