Say your TV remote suddenly stops working and you are trying to change the batteries. Then you remember you changed one of the two batteries just a couple of days ago. Which is it? Exchange one of them with a new one. No, not this one…

You might have had that experience. Guessing the right one out of two is okay, but what if there are four or even eight? What if you’re visually impaired? You don’t want to take your battery checker out of your dusty toolbox just to find out one old battery, do you?

So I was wondering if there is a rechargeable battery that can change its form to tell you how “hungry” it is. The thinner it is, the emptier the battery is. When it’s full, it’s just as straight as a normal battery. Even if your eyes are closed, you can feel it and know how much more you can use it until the next recharge.

Another merit is that when it’s thin, it’s much easier to take out from a packed battery room, especially if there are multiple betteries packed tight in line. Fat batteries don’t need to be changed anyway.