You raised the big battery elephant in the room question at the end, Chuck, about capacity. Will capacities rise to 4.2A-hr or 4.4A-hr? This of course relates directly to product weight. If capacities don't rise, eventually (soon, actually) portable devices relying on these things will hit a design wall, and the heavier devices will end up being performance-impaired.
What are the safety issues with the laminate-style lithium polymer batteries? It seemed that there was a lot of buzz a couple years ago about potential fires or even small explosions with lithium batteries, but I don't hear much about it anymore. Are these issues addressed in the polymer technology, laminate constructions or just in more robust housings? (Or not at all.)
The problem before was in cotnrolling the batteries themal characteristics. Sometimes if the battery was being discharged too rapidly the temperature rose and created the issues already noted. Smae thing can happen when charging the batteries. I think the solution was in the modification of the chemistry involved.
In terms of energy storage the total energy stored is getting interesting. And any uncontrolled release of that energy has to be dealt with in a safe manner. consider a stick of dynamite. I am not sure exactly how much energy it stores but when it is released suddenly it has dramatic effects. If that same energy could be controlled and released gradually in the form of electric current it would make a fine storage device but probably not rechargeable.
If one had a Lithium-Ion type battery with the same energy storage potential as a comparable size stick of dynamite it would certainly warrant very careful attention to catastrophic failure modes.
As I recall from chemistry class, the most energetic chemical reaction is the conversion of H to H2. That is Monatomic Hydrogen binding with another free Hydrogen into diatomic Hydrogen, H2. I believe it also liberates an electron. Probably not possible to make a battery out of it.
Is there some kind of Moore's law governing capacity in batteries as there is in processor design? Perhaps a technology that's the equivalent of multi-core for batteries? It would seem there would have to be as devices get smaller malland ser and as as people become ever more reliant on them on a 24/7 cycle. I don't see that demand dissipating any time soon.
The increased energy capacity combined with the lighter weight and the high discharge rates of Lithium Ion batteries has completely transformed certain areas of model airplane flying. Using battery power instead of gasoline or other liquid fuels has been played with for a long time but the emergency of the Lithium Ion in a soft, flexible (and lower weight) has completely transformed the hobby. Many fliers of Radio Controlled (R/C) planes have completely switched over to electric power (I know that I have) for planes ranging from very, very small (sub-ounce weights) to very large aircraft.
Electric propulsion systems have also expanded into control line planes (U/C - planes which fly with lines attached) and free flight (just fire them up and launch them into the air!). Absolutely amazing and quite liberating - no starters, no fuel cans, pumps, batteries for glow plugs, etc. Wonderful.
Of course there has been a bit of learning curve for the hobby. We needed new safety procedures (there is a lot of energy in a charged battery and they have been known to break into flame), new ways (using electronic speed controllers) to control motor speed, new brushless motors for high speed and high output applications, special battery chargers (seems like every battery chemistry has it's own special requirements for charging and maintenance) and the like.
That wasn't a lithium-polymer battery! It was an SLA (sealed lead-acid) one, and it was made by Gates (as I recall) quite a few years ago. They were the first to use a "super-gelled" electrolyte to make an extremely leak-proof cell structure. I saw a demo (of a nail being driven through one of their batteries which continued to deliver full power to a load!) at Comdex in Atlanta back in the 1980's. Very impressive!
Ahhh, I remember the company now. They joined with Dow to form Dow Kokam Battery. Kokam has a patented construction method that keeps the battery "safe". I recall seeing a demo video. Check out http://www.dowkokam.com/tech-cells.htm
Most machine design engineers will survey existing component manufacturers for standard linear guide products, limiting what they can do with their designs. Using extruded aluminum profile guides can customize machine designs while shrinking the bill of materials.
Practically all electronic devices today contain metals that may
be coming from conflict-ravaged African countries. And political pressures will increasingly influence how these minerals are sourced and used in products.
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