I'm a 30-plus-year veteran of electrical engineering with experience that spans many areas, including digital, analog, power, communications, and microcontrollers. I work for a company called MaxVision, which makes extreme-performance, ruggedized, transportable workstations. By some strange quirk of fate, Max Maxfield the (world's go-to techno guy) has his office in the same building as mine. Over the years, he has had to tolerate my very bad punny humor attempts over the coffee table, since we share a kitchen in our building.
One day, while I was contemplating a new joke to inflict upon everyone, I overheard a conversation between Max and our mechanical design expert, Eugene "Willie" Richards, about what type of batteries would be the best option for Max's robot project. Since I have considerable knowledge about batteries (robots too), and I was feeling some remorse about my previous puns, I held off on the jokes and offered my assistance.
Max said it would be useful to a lot of readers if I wrote a series of columns on batteries -- beginning with types, technologies, terminologies, specifications, and environment. Later we will cover specific types of batteries in more detail, considering most everything required to understand and select the appropriate technology for a particular application. Once we've considered everything in excruciating detail, we will be in a position to advise Max about the optimal battery technology for his robot.
The battery was invented by Alessandro Volta of Italy in 1800. I'm sure Volta would be amazed by how ubiquitous (and varied) his invention has become. Having said this, for some tasks, it might be more appropriate to select a capacitor, rather than a battery. Surprised? Well, you might at least consider using a capacitor whenever it is assured to have a regular, high-surge-capable supply of electricity. In some cases involving very light loads, it might even be possible to ignore the regular power application -- just charge a super-capacitor once, and it will survive all the way until discarded. Once we have discussed battery terminologies and technologies, the capacitor versus battery choice will hopefully become clear.
There are lots of factors to consider when choosing the battery technology for a particular application. In addition to relative size, weight, and cost (from cheap to expensive to "if you have to ask, you can't afford it"), the main considerations and factors I plan on covering in this series are as follows:
Environment (operating and storage): Temperature, air pressure, altitude, mechanical strain, vibration, mounting position, radiation hardening, corrosive attack, packaging/shape, storage or shelf life, disposal, waste products produced and outgassing, consumables required, safety, and materials/RoHS
Application: Types (including primary, secondary, and smart), technology, chemistries, efficiency and loss, charge/discharge cycle count and rates, depth of discharge, service life, memory effect, charging techniques, capacitor/battery hybrid, use cases, capacity, density (energy and weight), protection circuitry, measuring and gas gauge, quality, reliability, and recharge and run times
Since Volta's first crude models, many types of batteries have come into use. Some of these technologies are as follows.
Nickel metal hydride
Zinc-manganese dioxide (alkaline)
Lithium thionyl chloride
Lithium poly carbon monofluoride
Lithium sulfur dioxide
Lithium aluminium chloride
Lithium cobalt oxide
Lithium iron phosphate
Lithium manganese oxide
Lithium nickel manganese cobalt oxide
Lithium nickel cobalt aluminum oxide
Nuclear or atomic
I won't be able to cover all these technologies in depth -- just some of the more common and/or noteworthy ones. Please add a comment below if you think I've omitted some important technology or if you're interested in a particular one. If you need more information right now, you may find quick, specific answers to your battery-related questions at the
Battery University website.
In my next column I'll cover classifications, general specifications, and terminology. Until then, please post any questions or comments below.
Ivan: Some where in your articles it would be helpfull to discuss the shipping issues with different battery chemistryies. This is something that can catch both designers and PM's off guard, at least the first time they go thru it. :)
Crusty1: There are many 'rejuvinator' devices that are used here in the states for large truck batteries. If you can get an extra couple of months usage out of a battery it is worth the 8-10 hours that the process takes.
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. A similar treatment was touted to break loose sulfation in lead-acid cells. The applied voltage waveform shape and duration was critical to keep from doing too much damage. In some cases, it killed the remaining life, but was sometimes worth the risk.
This is mainly for non-rechargables (acctually it could apply to rechargable too). Is there a standard load voltage drop vs load that's used to indicate the internal battery resistance is to high for practical use ? Digital cameras tend to be very picky about power supply. I've taken digitial camera batteries deemed BAD by the camera and used them succesfully in other less picky electronics. ( I wouldn't suggest using them in a pace maker). This begs the question: Are we discarding nearly good batteries ? Maybe recycling usefull batteries or worse sending them to the land fill.
As a hearing aid engineer (and one of 8.5 million users) I'm particularly interested in zinc-air technology, specifically with humidity. One engineer I know calls it a fuel cell, but nstead of pumping in O2 it extracts it out of the air.
Useful for what to whome? That was the midevil period though so anything "strange" might have branded you a witch.. without Generators to charge batteries you couldn't do much - and we didn't have generators until 1873, but wow things cascaded quickly once we had power generation.
I am very interested in this subject and wish today's products would be made compatible with rechargable lithium cells running at 3.7v and normal alkalines at 1.5v so we could start having AAA, AA, 9V (3.7x3), etc pure lithium cells. I know it might be somewhat tricky, but it would be nice to get rid of heavy, single use, low power density alkaline land fille batteries for good. With the speed we replace electronics these day's it wouldn't take long.
Join our online Radio Show on Friday 11th July starting at 2:00pm Eastern, when EETimes editor of all things fun and interesting, Max Maxfield, and embedded systems expert, Jack Ganssle, will debate as to just what is, and is not, and embedded system.