09-06-2010, 09:49 PM
Introduction:
Now the technology is far beyond a leap but still The most limiting factor for all our current and future developments is The availability of power. Starting with simple mobile systems followed by complex networked environments with flexible nodes there is always the need for energy that comes not from the power socket. And since the applications get more complex, should last longer and work more robust the demand for mobile energy increases day by day. The most common solution to have mobile power is of course the battery. But the battery is one of the most laggard technologies within embedded systems. The evolution of battery technology has not been pushed by industrial development compared to processing power or disc capacity; batteries have just doubled their energy/volume ratio within a 10 year interval, processing power still raised as fast as predicted in Mooreâ„¢s law by factors more.
And batteries have some significant drawbacks
- Limited capacity:
Since batteries convert chemical into electric energy, their capacity is limited by the available volume for the chemistry. More and more applications are downsized and should work a long period. Also at some time a battery is exhausted and has to be exchanged. This is often not possible because the user has no more access to the system.
- Physical limits:
Temperature limits and mechanic conditions (e.g. shocks) are a huge problem to batteries. Since their capacity decrease with the temperature, they have to be planned oversized a lot. This increases cost and space consumption.
- Cost/lifetime:
Modern batteries, e.g. lithium-ion batteries, are quite expensive at a limited lifetime. For many mobile phone users it is common to buy more batteries than mobiles. But there are many applications that need very cheap hardware in a large numbers.
Other solutions for power generation besides batteries can be categorized by
energy source:
- Solar, using the light of the sun
- Thermal, using thermal differences in-between e.g. 2 areas
- Mechanical, using e.g. vibrations or bending
- Etc.
read full report
http://www.salzburgresearch.at/research/...ree-es.pdf