MIT Explains How To Turn an Old Car Battery Into a Working Solar Cell

There are over 1 billion cars in the world, and the vast majority of them use batteries made from lead. As lithium batteries replace these old timers, eventually there may be many of the lead suckers sitting in landfills. Which is why MIT wanted to find a way to reuse them—by turning them into a new kind of solar cell. It's surprisingly simple.


Well, maybe "simple" isn't the right word. But thanks to a new video produced by a MIT energy research team, it's surprisingly easy to understand. The team, which published its work in the Energy and Environmental Science, focused on fabricating a newer type of solar cell that uses perovskite, a mineral made of calcium titanate, that's being used to build cells that are nearly as efficient as the more conventional silicon solar cells most of us are familiar with.

According to MIT, solar cells made out of perovskite didn't make much sense originally, since they require the use of toxic lead. But given the fact that many car batteries may be thrown into dumps around the world down the road, an unexpected deal emerged: The lead from these batteries could be recycled into solar cells.


To demonstrate the process, they produced the video below—which shows how the electrode panels are "harvested" from an old car battery using a saw, then put through their paces on their way to becoming a cell. At one point, they even "roast" the Cathode lead dioxide for five hours:

So what's the exact exchange rate? According to the group, the amount of material harvested from just one car battery can make solar panels to power 30 homes.

It's a pretty incredible project, not only from a technical perspective but a broader societal one. The world is about to have a major dilemma on its hands, if toxic car batteries are no longer recycled to make new car batteries. "Once the battery technology evolves, over 200 million lead-acid batteries will potentially be retired in the United States, and that could cause a lot of environmental issues," one researcher told MIT News.

This is a way to transfer the embodied value of one technology into a newer, more nascent one, and it's a solution to a problem that's going to rear its head again and again in the future. We'd do well to focus on figuring out other ways to funnel the other rare earth minerals, metals, and materials from our outgoing tech into the new. [MIT News]


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Used lead batteries don't go in landfills. They get recycled, and the refund you get is pretty hefty, so you'd be stupid to throw it in your garbage bin.

Lead batteries won't be going away too quickly, since there a billion cars that still need one every 3 years or so. You can't stick a lithium battery in an existing car without overhauling the charging system. Even if demand for them goes down, the lead in them might get cheaper, but there are uses that don't require the power density of lithium, such as UPS back-up power, where a large cheap battery will still be welcome. Some of the cars built today will still be on the road 40 and 50 years from now, just think about the number of 60's classics still running.