@Caleb....I'm sure there's lots of tech like this, but just consider Peltier effect - discovered in the 1830's, but only in widespread used these days for coolers etc (and rings, as you recently pointed out, though as you also pointed out this is the complimentary Seebeck effect (ie generating electricity form a temperature difference, rather than Peltier which is generating a temperature difference form a current?))
Ivan, although nuclear RTGs are not for mainstream applications, I hope you will incldue them in your discussion, for the benefit of we space junkies. I have read that the old standby Pu-238 is not the optimum choice for deep space vehicle RTGs and I'm curious about the pros & cons of different radioactive isotopes for RTG use.
I also find it fascinating that even after more than 36 years in space, the 487 watt (at launch) batteries on Voyager 1 are still producing about 250 watts.
Thanks for selecting battery as a subject.I have been desining battery chargers in industry( Lead Acid) since 1972 for Indian Railways and Post and Telegraph Department. What I learned is they can use the LA batteries for more than 10 years. They used singal cell units with every day maintainence. However what I heard for my car battery themaximum life as per the auto repairer is one to three years as per usage of the car. Sulphatation, high starting current demand non tubular design and mobile use (Sunjected to acceleration in all direction) being the main problem.
I also heared about polymer conductor battery that has long life (may be now being used ih cell phones) But is there any varient in capacities comparable to lead acid batteries?
Keep in mind a Pb-based battery needs to be kept fully charged or it dies, so it is derated to allow for capacity loss over the expected life of a battery. And in some countries you need to crank at very low temperature where you have only say 25% capacity available. In temperate climates you can get away with a much smaller battery, especially when you consider you do not have to keep the battery fully charged. It is commonly stated you need only half the capacity of a Pb-based battery. Shipping of Li is an issue, however if each cell is less than 20Wh then it is not that hard.
@eetcowie: "Also, Nickel Cadmium types were notorious for growing metal-fiber 'wires', that would partially short out a cell. There appeared a capacitor-based rejuvenator that would pulse a high-current into the cell to blow out the metal fibers and breathe new life."
Back in the mid-to-late 70s Popular Electronics had a simple circuit for a NiCd zapper. It had a 24V transformer and a full-wave bridge that charged a capacitor, and it had a selector switch (charge or zap), a pushbutton to zap, and a meter to monitor the charge on the cap and on the battery. A friend built one to try to resurrect some surplus NiCds he'd bought. One let out a tremendous FLASH and a ZAP, and then started to take a charge. The article said if it didn't start taking a charge after 2 or 3 zaps it never would. He was able to recover most of the "dead" batteries. Not much of a special waveform, but at the cost of used batteries, you didn't lose much by trying. I doubt that would work for Li cells!
I also read that another failure mode with NiCds was that a weak cell caught in a string of good cells would be charged in reverse.