Lead-acid batteries have been around for over a century and go into more than 100 million vehicles annually, including boats, forklifts, and wheelchairs, as well as cars and trucks. But new technologies, tougher anti-pollution laws, and new consumer demands could lead to a major reduction in their use, says Peter Harrop, Chairman of IDTechEx, a market research and consulting firm with U.S. headquarters in Cambridge, Mass.
Harrop points out several factors that will lead to the demise of the traditional car battery. They include the rising popularity of hybrid electric vehicles (HEVs), including those for industrial and commercial use. For example, Harrop estimates that in a few years, a million Toyota Prius with nickel-metal-hydride or lithium-ion batteries will be sold annually, and more hybrid and pure-electric models will become available every year. The trend is to power these electric and hybrid vehicles by lithium-ion batteries rather than lead-acid versions.
One reason for the rising dominance of lithium-ion batteries is the increasing popularity of instant stop-start - a feature which automatically switches off the motor to save fuel when a vehicle stops, as when stopped at a light. It turns out that start-stop doesn't work well with traditional lead-acid batteries, particularly at low temperatures, because they cannot recharge quickly enough. For example, tests show that conventional batteries lose 7 to 16% of their available capacity after just one week in a start-stop vehicle. Lead-acid batteries also don't handle regenerative braking well for the same reason. In contrast, lithium-ion alternatives can be recharged quickly without reducing battery life or performance.
Indications are that industrial and commercial vehicles will also switch to lithium-ion batteries, even if they lack start-stop features. It often takes three lead-acid batteries to power a forklift: one being charged, one cooling down after charging, and one actually powering the forklift. Even then, battery life is short, says Harrop. Lithium-ion batteries can be charged and reused more easily and with less manpower. They are also better in the type of hybrid powertrains becoming more widely used in outdoor forklifts and earthmovers.
Plus, over the next decade, the cost of lithium-ion batteries should drop by at least one-third, says Harrop, At the same time, IDTechEx analysts think energy-harvesting technologies and devices will soon become more widespread, reducing the amount of battery power needed by vehicles.
Another factor reducing the need for lead-acid batteries will be the more widespread use of fuel cells in fleets of forklifts, taxis, buses, and trucks, says Harrop. He points out that fleet owners should have few problems with hydrogen distribution. And they are in a good position to make the switch to fuel cells because business owners are usually concerned more about long-term payback than up-front costs.
Fuel-cell powered cars should soon be on the market and reduce demand for lead-acid batteries, according to IDTechEx. And fuel cells will eliminate the problems of limited range and long charging times that plague many present day EVs and HEVs.
Supercapacitors are also coming on strong. Double-layer capacitors, also known as ultracapacitors or supercapacitors, have four times the life of rechargeable batteries, tolerate faster charge-discharge cycles, and are made from readily available materials. Their self-discharge and energy density have been poor, but advances have led to versions that self-discharge in a month rather than a day and to others with the energy density of a lead acid battery. There are currently buses running solely on supercapacitors. Even Elon Musk, founder of the company that makes the Tesla electric car, thinks supercapacitors rather than batteries are the future.
It isn't just the U.S. and Europe going off lead-acid batteries. China is abandoning them as well. China wants to eliminate the pollution and injuries that come from smelting, making, and disposing of lead batteries. To this end, for 2011 the Chinese government cut lead-acid battery production by 42% compared with production levels in 2010. IDTechEx predicts few of the 1,930 inspected Chinese manufacturers will remain and most unlicensed companies will be found and put out of business.
The end of the lead-acid battery's dominance will come more suddenly than most expect, says Harrop, though he concedes that niche markets for lead acid will remain.