Advantages:
Fast and simple charge – even after prolonged storage.

High number of charge/discharge cycles – if properly maintained, the NiCd provides over 1000 charge/discharge cycles.

Good load performance – the NiCd allows recharging at low temperatures.

Long shelf life – in any state-of-charge.

Simple storage and transportation.

Good low temperature performance.

Forgiving if abused – the NiCd is one of the most rugged rechargeable batteries.

Economically priced – the NiCd is the lowest cost battery in terms of cost per cycle.

Available in a wide range of sizes and performance options – most NiCd cells are cylindrical.
 
Limitations:
Relatively low energy density – compared with newer systems.

Memory effect – the NiCd must periodically be exercised to prevent memory.

Environmentally unfriendly – the NiCd contains toxic metals. Some countries are limiting the use of the NiCd battery.

Has relatively high self-discharge – needs recharging after storage.

Researchers at the U.S Department of Energy’s Argonne National Laboratory are working to develop commercially viable Li-air batteries.

Li-air batteries use a catalytic air cathode that supplies oxygen, an electrolyte and a lithium anode. The technology has the potential to store almost as much energy as a tank of gasoline, and will have a capacity for energy storage that is five to 10 times greater than that of Li-ion batteries.

The DOE has awarded the lab $8.8 million to build out and outfit three battery research facilities that will be used for battery prototyping, materials production scale-up and post-test analysis.

“The obstacles to Li-air batteries becoming a viable technology are formidable and will require  innovations in materials science, chemistry and engineering,” said Argonne Director Eric Isaacs. “We have a history of taking on scientific challenges and overcoming them. Argonne is committed to developing Li-air battery technologies. In fact, we’ve made it a ‘grand research challenge’ at the laboratory.”

Battery manufacturers are well aware of customer needs and have responded by offering battery packs that best suit the specific application. The mobile phone industry is an example. For this market, the first thing is the small size and high energy density. Longevity comes in second.

The mention of NiMH on a battery pack does not guarantee a high energy density. A prismatic NiMH battery for a mobile phone, for example, is made for slim shape and may only have an energy density of 60Wh/kg. The cycle count for this battery would be limited to around 300. In comparison, a cylindrical NiMH offers energy densities of 80Wh/kg and higher. Still, the cycle count of this battery will be moderate to low. High durability NiMH batteries, which are intended for industrial use and the electric vehicle enduring 1000 discharges to 80 percent depth-of discharge, are packaged in large cylindrical cells. The energy density on these cells is 70Wh/kg.

Similarly, Li-ion batteries for defense applications are being produced that far exceed the energy density of the commercial equivalent. Unfortunately, these super-high capacity Li-ion batteries are called unsafe for public. Neither would the general public be able to afford to buy them.

Not far from the frozen tundra, green technological cooperation between Russia and China is heating up.

A technology transfer plan between the 11 year-old Chinese company Thunder Sky Energy Group and Russia’s state-run agency for encouragement of nanotechnology, RusNano, will lead to joint production of Lithium-ion batteries for many industrial uses.

In energy and telecoms as well as the most prominent Lithium-ion target sector-electric vehicles-Russian production will ramp up with Chinese assistance.

The production facilities will be built in the Siberian city of Novosibirsk (literally, “New Siberian”) and will add to Thunder Sky’s output capacity while creating some 500 jobs in Russia and giving Moscow-led investment arm RusNano a quick start toward Russian prominence in the high-tech battery sector.

Just under $500 million in investment in 2010 and 2011 will draw more than $500 million in sales by 2011, it is hoped.

Russian project heads plan to use local materials and local labor to build on Thunder Sky’s production model and solidify eastern Russia as an efficient production base that can serve both Asian and European markets with lithium batteries.

The two-way radio market uses mostly NiCd batteries. In the last few years, environmental agencies have been attempting to discourage the use of NiCd, especially in Europe. NiMH have been tried and tested in two-way radios for a number of years but the results are mixed. Shorter cycle life compared to NiCd is the major drawback.

The reasons for the relatively short life of NiMH are multi-fold. NiMH is less robust than NiCd and has a cycle life expectancy that is half or one third that of the standard NiCd. In addition, NiMH prefers a moderate discharge current of 0.5C or less. A two-way radio, on the other hand, draws a discharge current of about 1.5A when transmitting at 4W of power. High discharge loads shorten the life of the NiMH battery considerably.

NiCd has the advantage of maintaining a low and steady internal resistance throughout most of its service life. Although low when new, NiMH increases the resistance with advanced cycle count. A battery with high internal resistance causes the voltage to drop when a load is applied. Even though energy may still be present, the battery cannot deliver the high current flow required during transmit mode. This results in a drop in voltage, which triggers the ‘low battery’ condition and the radio cuts off. This happens mostly during transmission.

The Li-ion has been tested for use with two-way radios but has not been able to provide the ultimate answer. Higher replacement costs, restrictions posed by the safety circuit and aging pose limitations on this battery system.