Thursday, October 14, 2010
New battery research yielding results
Lithium ion is the present battery technology of choice for its dense energy storage but heat produced during both charging and discharging cycles is a serious problem. Just remember stories of laptop computers and cell phones catching fire and notice how warm your digital camera battery is immediately after recharging. A few solutions aimed at this problem are beginning to appear.
Quallion, based in California, has developed a partial cure for heat build-up in Li-ion batteries for use in heavy-duty trucks to reduce time spent with the engine idling. Their design uses arrays of interconnected, smaller batteries that produce less heat individually and are easier to keep cool en-masse. The arrays are connected to allow continued performance even if individual cells fail. The Li-ion battery arrays weigh much less than a similar amount of storage using conventional lead-acid batteries. Using battery power for interior lights and cooling/heating while parked would significantly reduce the amounts of greenhouse gasses produced by the idling diesel engines of these over-the-road trucks.
Another coming change applies new research to the anode(negative side) of Li-ion batteries. Graphite is the present material of choice but has a limited capacity to hold lithium. The amount of lithium determines the amount of energy that can be stored in a given battery. Silicon can hold nearly ten times as much lithium as graphite but develops cracks after several charge/discharge cycles because of the expansion/contraction caused by the heat produced. Putting micron-sized pores in the silicon surface give enough room for expansion/contraction without cracking. This breakthrough will allow batteries of the same size and weight to hold many times the amount of power now possible. Much smaller batteries for large-scale uses, such as electric vehicles and buffers between solar/wind installations and the commercial power grid should soon be on the way.
Cathode(positive side) research is also bearing fruit. BASF is experimenting with a Nickel-Cobalt-Manganese(NCM) cathode material that could have wide applications. They claim up to 60% more energy storage capacity for same-sized batteries. This amount of increased storage could mean up to 50% more distance per charge for an electric vehicle. For consumer electronics it would mean greatly extended use time for laptop computers, cell phones, etc…
One of the older and better-established battery technologies might also make a comeback thanks to new research. Sodium-Nickel-Chloride(Na-beta) batteries have been around for a long time but like other types of rechargeables produce heat when recharged. It seems changing the shape of the battery from the traditional long cylinder to a flat pancake produces much less heat. An added bonus is the ability to deliver up to 30% more power. The materials that go into Na-beta batteries are cheaper and more easily available than those required for Li-ion batteries.
Another older battery technology is also being revived. GP Batteries received this year’s Battery Manufacturer of the Year-Alternative Chemistries award. They developed a new Nickel-Metal Hydride battery for use in electric vehicles.
Continued research and creative thinking is all of the above areas are needed. Battery storage plays an important role in the continued integration of greener/renewable energy sources into everyday life. Grid interface is a major problem for more widespread use of intermittent power generation like wind and solar. Better battery storage solutions are one way to move forward.
While battery company stocks have been lagging behind other “green” sectors, this situation will not last forever. Batteries have too large a role to play in the success of alternative energy production. The companies that best take advantage of new research will come out ahead in market share and stock share price. I watch several of the largest and most innovative battery companies closely and think they may soon follow the solar PV industry along the path of increasing share prices.