A US study has indicated that batteries used in electric and hybrid cars could have a lifespan of up to 20 years – much longer than car-makers are guaranteeing.
Some brands, including General Motors and Toyota, will only guarantee the batteries in their cars for up to eight years.
The American Chemical Society investigated the question of battery life in cars but only looked at the more expensive lithium-ion units, and not the nickel-metal hydride types used in the Toyota Prius in some markets.
The results are interesting. “The (lithium-ion) battery pack could be used during a quite reasonable period of time ranging from five to 20 years depending on many factors,” Mikael Cugnet, a project manager at France’s Atomic and Alternative Energy Commission, told the society’s meeting in New Orleans.
“That’s good news when you consider that some estimates put the average life expectancy of a new car at about eight years.”
Toyota introduced its Prius hybrid to Australia in 2001, however, since its launch there the car has used the cheaper, less energy-dense nickel-metal hydride batteries, though the recently introduced Prius V petrol-electric hybrid people-mover, uses the more expensive batteries.
Dr Cugnet’s study noted that deterioration in lithium-ion batteries was affected most by heat, with temperatures above 30 degrees affecting performance “instantly and even permanently” if it was for an extended period, which is not good news for Thailand, with the tropical temperatures well over 30 degrees at present.
Dr Cugnet also said electric vehicle owners needed to closely monitor a battery’s charge in hot weather, as a fully charged battery was “more vulnerable to losing power”.
The study ranked a battery as beyond its useful life after it had lost more than 20 percent of its original charge capacity.
Nissan’s Leaf electric car came under close scrutiny last year after US owners started to complain about big drops in the lithium-ion battery pack’s ability to hold a charge.
Owners in warmer parts of the US, including Arizona, Texas and California, started noting that their Leaf was losing up to a quarter of its battery capacity in a matter of months.
The website mynissanleaf.com estimates the rate of battery deterioration in Leaf electric cars worldwide and predicts that a car driven in Melbourne would fall to 82 percent of charge capacity – just above the study’s cut-off of a 20 per cent loss of charge capacity – within five years, and would fall to 70 percent in 11 years.
