Even one-in-a-million problems with lithium ion batteries can result in many fires because there are billions of them in use now, with dozens sometimes stacked together in a single device.Experts say lithium ion batteries are more dangerous because their electrolyte, the liquid that allows ions to move between electrodes in the battery, is more flammable than the substance in older type batteries. Those older types include the lead-acid batteries in most cars and the nickel cadmium batteries that are often in video equipment and power tools. Still, MIT materials science and engineering professor Gerbrand Ceder and others said the safety problems can be fixed. Change doesn't come often in the battery field. "The big advances in battery technology happen rarely. It's been more than 200 years and we have maybe five different successful rechargeable batteries," said George Blomgren, a former senior technology researcher at Eveready and now a private battery consultant. "It's frustrating." Alessandro Volta â¿¿ for whom the volt is named â¿¿ invented the first useful battery in 1800. That was long before other breakthrough inventions like the internal combustion engine, telephone, car, airplane, transistor, computer and Internet. But all of those developments have seemed to evolve faster than the simple battery. The lead-acid car battery "has been around for 150 years more or less," Whitacre said. "This is a remarkable testament to first how robust that chemistry is and how difficult change is." Battery experts are split over what's next. Some think the lithium ion battery can be tinkered with to get major efficiency and storage improvements. Amatucci said he thinks we can get two to three times more energy out of future lithium ion batteries, while others said minor chemical changes can do even more. But just as many engineers say the lithium ion battery has run its course.