[mikestew]

Would a battery heating up just a bit help make that comfortable for me?

In something ring-sized? Maybe for about five minutes, and then the battery dies. (I assume you mean using resistive elements to create heat; heating the actual battery seems like a bad idea.)

[skyberrys]

My bad, I read the article wrong, they are only concerned with thermal heating while it's charging. I did seem unexpected that a ring could heat up enough to be a concern while being worn.