SPEAKER_00: Amazing, fascinating stories of inventions, ideas and innovations. Yes, this is the podcast about the things that have helped to shape our lives. Podcasts from the BBC World Service are supported by advertising.
SPEAKER_02: 50 Things That Made the Modern Economy with Tim Harford Murderers in early 19th century London sometimes tried to kill themselves before they were
SPEAKER_01: hanged. Failing that, they asked their friends to give their legs a good hard tug as they dangled from the gallows. They wanted to be absolutely certain they were dead. Their freshly hanged bodies they knew would be handed to scientists for anatomical studies. They didn't want to survive the hanging and regain consciousness while being dissected. If George Foster, executed in 1803, had woken up on the lab table, it would have been in particularly undignified circumstances. In front of an enthralled and slightly horrified London crowd, an Italian scientist with a flair for showmanship was sticking an electrode up Foster's rectum. Some in the audience thought Foster was waking up. The electrically charged probe caused his lifeless body to flinch and his fist to clench. Applied to his face, electrodes made his mouth grimace and an eye twitch open. One onlooker was apparently so shocked he dropped dead shortly after. Foster's body was being galvanised. A word coined for Luigi Galvani, the Italian scientist's uncle. In 1780s Italy, Galvani had discovered that touching the severed legs of a dead frog with two different types of metal caused the legs to jerk. Galvani thought he'd discovered animal electricity and his nephew was carrying on the investigations. Galvanism briefly fascinated the public, inspiring Mary Shelley to write her story of Frankenstein. Galvani was wrong. There is no animal electricity. You can't bring hanged bodies back to life and Victor Frankenstein's monster remains safely in the realms of fiction. But Galvani was wrong in a useful way. Because he showed his experiments to his friend and colleague Alessandro Volta, who had a better intuition about what was going on. The important thing Volta realised, wasn't that the frog flesh was of animal origin, it was that it contained fluids that conducted electricity, allowing charge to pass between the different types of metal. When the two metals were connected, Galvani's scalpel touching the brass hook on which the legs were hung, the circuit was complete and a chemical reaction caused electrons to flow. Volta experimented with different combinations of metal and different substitutes for frogs legs. In 1800 he showed that you could generate a constant steady current by piling up sheets of zinc, copper and brine soaked cardboard. Volta had invented the battery. But it wasn't especially practical, not at first. The metals corroded, the saltwater spilled, the current was short lived and it couldn't be recharged. It was 1859 before we got the first rechargeable battery, made from lead, lead dioxide and sulphuric acid. The first dry cells, the familiar modern battery, came in 1886. The next big breakthrough took another century. It arrived in Japan. In 1985 Akira Yoshino patented the lithium-ion battery. Sony later commercialised it. Researchers had been keen to make lithium work in a battery as it's very light and highly reactive. Lithium-ion batteries can pack large amounts of power into a small space. Unfortunately lithium also has an alarming tendency to explode when exposed to air and water, so it took some clever chemistry to make it acceptably stable. Without the lithium-ion battery, mobiles would likely have been much slower to catch on. Consider what cutting edge battery technology looked like when Yoshino filed his patent. Motorola had just launched the world's first mobile phone, the DynaTAC 8000X. It weighed nearly a kilogram and early adopters affectionately knew it as the brick. Its talk time was 30 minutes. The technology behind lithium-ion batteries has certainly improved. 1990s laptops were clunky and discharged rapidly. Today's sleek ultra-portables will last for a long-haul flight. Still, battery life has improved at a much slower rate than other laptop components such as memory and processing power. Where's the battery that's light and cheap, recharges in seconds and never deteriorates with repeated use? We're still waiting. Another major breakthrough in battery chemistry may be just around the corner. But history counsels caution. Game-changers haven't come along often. Anyway, in the coming decades, the truly revolutionary development in batteries may not be in the technology itself, but in its uses. We're used to thinking of batteries as things that allow us to disconnect from the grid. We may soon see them as the thing that makes the grid work better. Gradually, the cost of renewable energy is coming down. But even cheap renewables pose a problem. They don't generate power all the time. Even if the weather were perfectly predictable, you'd still have a glut of solar power on summer days and none on winter evenings. When the sun isn't shining and the wind isn't blowing, you need coal or gas or nuclear to keep the lights on. And once you've built those plants, well, why not run them all the time? A recent study of southeastern Arizona's grid weighed the cost of power cuts against the costs of carbon dioxide emissions, and concluded that solar should provide just 20% of power. And Arizona is a pretty sunny place. If grids are to make more use of renewables, we need better ways of storing energy. One time-modeled solution is pumping water uphill when you have energy to spare, and then, when you need more, letting it flow back down through a hydro power plant. But that requires conveniently contoured mountainous terrain, and that's in limited supply. Could batteries be the solution? Perhaps. It depends partly on the extent to which regulators nudge the industry in that direction, and partly also on how quickly battery costs come down. Elon Musk hopes they'll come down very quickly indeed. The entrepreneur behind electric car maker Tesla is building a gigantic lithium-ion battery factory in Nevada. Musk claims it will be the second largest building in the world, behind only the one where Boeing manufacture their 747s. Tesla is betting that it can significantly wrestle down the costs of lithium-ion production, not through technological breakthroughs, but through sheer economies of scale. Tesla needs the batteries for its vehicles, of course, but it's also among the companies already offering battery packs to homes and businesses. If you have solar panels on your roof, a battery in your house gives you the option of storing your surplus daytime energy for nighttime use rather than selling it back to the grid. We're still a long way from a world in which electricity grids and transport networks can operate entirely on renewables and batteries, but the aim is becoming conceivable. And in the race to limit climate change, the world needs something to galvanize it into action. The biggest impact of Alessandro Volta's invention may be only just beginning.
