The battery - electric device, that converts chemical energy into electrical energy has become a common power source for many industrial and household applications, and is now a multi-billion dollar industry.

Lead-acid batteries are inexpensive, safe, and reliable. But low specific energy, poor cold temperature performance, and short calendar and cycle life are still impediments to their use. Nickel-metal hydride batteries offer reasonable specific energy and specific power capabilities. These batteries have a much longer life cycle than lead acid batteries and are safe. The main drawbacks are their high cost, high self-discharge, the need to control losses of hydrogen, and their low cell efficiency. Nickel-cadmium batteries, used in many electronic consumer products, have higher specific energy and better life cycle than lead-acid batteries but they do not deliver sufficient power and are not being considered for HEV applications.

The lithium ion batteries and lithium ion polymer batteries have high specific power, high-energy efficiency, good high-temperature performance, and low self-discharge. Components of lithium ion batteries could also be recycled. These characteristics make lithium ion and lithium ion polymer batteries suitable for hybrid electric vehicle (HEV) applications. To make them commercially viable, further development is needed including improvement in cycle life, higher degree of battery safety, abuse tolerance, and acceptable cost.

Many teams from university and industry conduct research and development on many different types of batteries to improve their performance and life-cycle costs.

Lithium-ion batteries with nanotube electrodes. Researchers at MIT led by chemical engineering professor Paula Hammond and mechanical engineering professor Yang Shao-Horn developed a lithium-ion battery with a positive electrode made of carbon nanotubes delivers 10 times more power than a conventional battery and can store five times more energy than a conventional ultracapacitor.

Researchers have been trying to make electrodes for lithium-ion batteries from carbon nanotubes because their high surface area and high conductivity promise to improve both energy and power density relative to conventional forms of carbon. The electrodes made by the MIT group have a very high surface area for storing and reacting with lithium. This high surface area is critical both to the high storage capacity of the electrodes, as well as their high power: because lithium is stored on the surface, it can move in and out of the electrode rapidly, enabling faster charging and discharging of the battery. The key to the performance of the MIT electrodes is an assembly process that creates dense, interconnected, yet porous carbon-nanotube films, without the need for the fillers.

IBM Battery Research. IBM is beginning a project that will lead to the commercialization of lightweight, powerful, and rechargeable batteries for the electrical grid and the electrification of transportation that store 10 times as much energy as today's. The company will partner with U.S. national labs to develop a promising but controversial technology that uses energy-dense but highly flammable lithium metal to react with oxygen in the air.

Lithium metal-air batteries can store a tremendous amount of energy, more than 5,000 watt-hours per kilogram. That's more than ten-times as much as today's high-performance lithium-ion batteries, and more than another class of energy-storage devices. Instead of containing a second reactant inside the cell, these batteries react with oxygen in the air that's pulled in as needed, making them lightweight and compact.

IBM is pursuing the risky technology instead of lithium-ion batteries because it has the potential to reach high enough energy densities to change the transportation system, says Chandrasekhar Narayan, manager of science and technology at IBM's Almaden Research Center, in San Jose, CA. One of the project's goals is a lightweight 500-mile battery for a family car. The Chevy Volt can go 40 miles before using the gas tank, and Tesla Motors' Model S line can travel up to 300 miles without a recharge.

One of the main challenges in making lithium metal-air batteries is that "air isn't just oxygen," says Jeff Dahn, a professor of materials science at Dalhousie University, in Nova Scotia. "humidity is the death of lithium". When lithium metal meets water, an explosive reaction ensues.

In addition to Oak Ridge, IBM will partner with Lawrence Berkeley, Lawrence Livermore, Argonne, and Pacific Northwest national labs.

Research on lithium-metal batteries stalled about 20 years ago. In 1989, Canadian company Moli Energy recalled its rechargeable lithium-metal batteries, which used not air but a more traditional cathode, after one caught fire; the incident led to legal action, and the company declared bankruptcy. Soon after, Sony brought to market the first rechargeable lithium-ion batteries, which were safer, and research on lithium-metal electrodes slowed nearly to a halt. After restructuring, Moli Energy refocused its research efforts and is now selling lithium-ion batteries under the name Molicel. Only a handful of labs around the world, including those at PolyPlus Battery, in Berkeley, CA, Japan's AIST, and St. Andrews University, in Scotland, are currently working on lithium-air batteries.

Batteries based on lithium-ion iron-sulfide chemistry. A British company, Qinetiq, is testing a new type of lithium-ion battery for hybrids and electric vehicles that could be substantially cheaper and more powerful than existing batteries. The battery is based on lithium-ion iron-sulfide chemistry, which has a number of advantages over the chemistry of existing batteries, says Gary Mepsted, technical manager for Qinetiq's power sources group. The new battery would cost half as much as existing vehicle batteries and could last longer and recharge more quickly that other lithium batteries. Mepsted says that compared to standard lithium-ion batteries, the new battery has demonstrated about 1.6 times the energy density (which would extend a plug-in electric's range) and a 50 percent higher power density (which would let hybrids charge and discharge more rapidly).

Researchers have long viewed lithium-ion batteries as an attractive alternative to the expensive metal-based batteries now used in hybrids. But although standard lithium-ion batteries are relatively cheap and can store about twice as much energy as standard nickel metal hydride cells, developers have had to overcome a number of technological challenges to make them practical for vehicles. Another issue is safety, says Jeff Dahn, a professor of physics and chemistry at Dalhousie University in Halifax, Canada. In small devices like cell phones, this is less of an issue, he says. "But in large cells, it's hard to remain stable under abuse conditions." Such conditions include overcharging or collisions, which can cause the batteries to combust or even explode. Qinetiq's approach involves making cathodes from lithium-ion iron sulfide instead of the more common lithium-cobalt oxide. Because this chemistry results in two lithium ions for every sulphide, it creates a massive increase in energy density.

Zinc-air against lithium-ion batteries. A Swiss company has developed rechargeable zinc-air batteries that can store three times the energy of lithium ion batteries, by volume, while costing only half as much. ReVolt of Staefa, Switzerland, plans to sell small "button cell" batteries for hearing aids starting next year and to incorporate its technology into ever larger batteries, introducing cell-phone and electric bicycle batteries in the next few years. It is also starting to develop large-format batteries for electric vehicles.

The battery design is based on technology developed at SINTEF, a research institute in Trondheim, Norway. ReVolt was founded to bring it to market and so far has raised 24 million euros in investment. James McDougall, the company's CEO, says that the technology overcomes the main problem with zinc-air rechargeable batteries - that they typically stop working after relatively few charges. If the technology can be scaled up, zinc-air batteries could make electric vehicles more practical by lowering their costs and increasing their range.

Unlike conventional batteries, which contain all the reactants needed to generate electricity, zinc-air batteries rely on oxygen from the atmosphere to generate current. In the late 1980s they were considered one of the most promising battery technologies because of their high theoretical energy-storage capacity, says Gary Henriksen, manager of the electrochemical energy storage department at Argonne National Laboratory in Illinois. The battery chemistry is also relatively safe because it doesn't require volatile materials, so zinc-air batteries are not prone to catching fire like lithium-ion batteries.

Nonrechargeable zinc-air batteries have long been on the market. But making them rechargeable has been a challenge. Inside the battery, a porous "air" electrode draws in oxygen and, with the help of catalysts at the interface between the air and a water-based electrolyte, reduces it to form hydroxyl ions. These travel through an electrolyte to the zinc electrode, where the zinc is oxidized - a reaction that releases electrons to generate a current. For recharging, the process is reversed: zinc oxide is converted back to zinc and oxygen is released at the air electrode. But after repeated charge and discharge cycles, the air electrode can become deactivated, slowing or stopping the oxygen reactions. This can be due, for example, to the liquid electrolyte being gradually pulled too far into the pores, Henriksen says. The battery can also fail if it dries out or if zinc builds up unevenly, forming branch-like structures that create a short circuit between the electrodes.

Self-sustained surface tension pumped electrokinetic accumulator. The researchers of Nizhyn Laboratories of Scanning Devices are working to develop a new type of wet battery with internal device – charger, imbedded into the construction of accumulator. This recharger is a capillary pumped electrokinetic nanocell, which periodically renews the chemical composition and structure of substances of electrolyte and of electrodes.

The molecular power technologies and among them electrokinetic technologies are the more promising to receive clear sustainable energy in near future and can be used to recharge wet batteries. But another problem exists: Where to find energy to boost electrokinetic’s? The team of Nizhyn Laboratories of Scanning Devices proposes to use a surface tension for creation of liquid flux.

The energy of surface tension appears in a capillary structure on the boundary of two phases (liquid and solid) as a result of molecular interaction in contiguous tangent phases. The power possibilities of surface layer are explicated by the work, which is necessary to transfer the molecules from the volume phase into a boundary layer. This transfer of molecules goes to the increase of surface energy – creation of surplus of energy of particles within the boundary layer in comparison with their energy in the volume of liquid. The energy of surface tension that appears on the boundary of two phases is transformed into the motion of liquid flux by use of the capillary structure.

With the purpose to increase the effectiveness of capillary structure and to boost the speed of electrolyte lifting through the capillaries the engineers researches very thin (nano)tubes and hope to receive the capillary structures with significantly improved properties. The point is that the character of interaction of molecules of liquid moving in very thin tubes with other molecules of liquid and of material of capillaries walls differs significantly. In limit, when the sizes of capillaries become close to the sizes of molecules of liquid, the surface tension on the boundary of phases increases by factor of 10. The use of nanotubes makes the process of recharging more productive.

This closed cycle self-sustained surface tension pumped electrokinetic accumulator has low cost and provides the possibility of the industrial and domestic use.

With the use of intrinsic electrokihetic nanocells embedded in a common container the parts of accumulator (electrodes and electrolyte) do not degrade as much when repeatedly charged and recharged. This could lead to smaller, lighter batteries in near future.

GM Battery Research Lab. GM officially opened a 3,000-square-meter battery lab at its technical center in Warren, MI. The lab is being used to test battery cells and packs for the forthcoming Volt plug-in hybrid vehicle, which it will continue to develop. The lab will allow the engineers to test the packs under extreme conditions to determine whether they will last for the life of the car.

Fritz Henderson, GM's CEO, is using the Volt and the battery lab to highlight a new direction for the automaker. Henderson recently called the lab the "lifeblood of our future". The company is also developing batteries for the second and third generation of the Volt vehicle, which involves evaluating different battery materials and cells to find ones that store more energy, making it possible to use fewer of them.

Lithium ion battery maker LG Chem also cooperates with GM to increase life of batteries.

The United States stimulus bill. The nearly $790 billion economic stimulus legislation contains tens of billions of dollars in loans, grants, and tax incentives for advanced battery research and manufacturing, as well as incentives for plug-in hybrids and improvements to the electrical grid, which could help create a market for these batteries. The stimulus bill sets aside $2 billion in grants for manufacturing advanced batteries, plus tax credits to cover 30 percent of the cost of a plant (up to $2.4 billion in total credits). This is in addition to $7.5 billion in loans authorized in a previous bill for manufacturing advanced technology for vehicles, which includes batteries. Employees for these factories could be trained as part of $500 million in funding for retraining workers for green jobs. There is also $16.8 billion going to energy efficiency and renewable energy, which will likely include money for battery research to bring down costs and improve performance.

Significant advances in battery materials, including the development of new lithium-ion batteries, have been made in the United States in the past few years. But advanced battery manufacturing is almost entirely overseas, particularly in Asia. As a result, advanced battery startups in the United States typically have their batteries made outside the United States. But this need not be the case, says Prabhakar Patil, the CEO of Compact Power, a subsidiary of the South Korean company LG Chem, based in Troy, MI. Battery manufacturing is largely automated, so labor costs aren't much of a concern, he says. Rather, the battery industry developed in Asia because countries there, particularly Japan, developed portable electronics and hybrid vehicles, creating a market for batteries.

By Vasil Sidorov on June 27, 2010 in Queltanews.com

sidorovvasil@gmail.com