I’m sitting here looking at a small pile of batteries on my desk. I do tend to use rechargeable batteries as often as I can, but there are some things that just don’t work as well with them. And so, as time goes on, I tend to acquire dead batteries on my desk, before eventually taking them out with other e-waste.
Why single-use batteries work better
A battery is an interesting thing. Essentially it’s a cylinder filled with goo. That goo has a unique property. If you put an electric charge into it (carefully) it will retain that charge until something else draws it out.
Single-use batteries tend to undergo a mostly irreversible change as they expend their energy. It is technically possible to recharge a single use battery, but the energy stored goes down so dramatically after the first charge cycle that it’s not worth it.
Single-use batteries tend to be able to hold more energy and release it over a longer period of time. To some degree, that’s because single-use batteries have been in use longer and we’ve seen more advancements with them. Rechargeable batteries have been around for 100 years or more, but people stopped really improving them after the first time electric cars went out of favor in the early 20th century. That battery in your car, perhaps the most common of rechargeable batteries, isn’t terribly different from the way it was in your grandparents’ day.
Getting better all the time
Single-use batteries have seen refinements in their chemical makeup that have meant that have less ongoing discharge. As batteries are charged, they slowly give up that charge even when there is no draw on them. Today’s batteries are much more stable in that regard. Some brands advertise that their batteries can last a decade in storage, and I say it’s quite possible.
At the same time, single-use batteries have seen improvements in the amount of energy they can store. All batteries of the same type should put out the same amount of current when new. But as they age and expend their energy, the amount of current drops. Single-use batteries tend to keep their current flowing for a longer period, and when they go dead, there’s a more steep dropoff. Rechargeable batteries have more of a tendency to drain slowly and they may reach the point where they don’t power anything, even though there’s still current in there. It’s just not enough to do the work.
More and more batteries are of the rechargeable type. Rechargeable batteries are designed so that they don’t undergo a permanent change as they charge and discharge, so that they can get charged over and over again. We all use rechargeable batteries in our phones, and we’re familiar with the way they work.
When new, rechargeable batteries seem invincible. We’ve all experienced the joy of having a new phone with seemingly endless (well in reality, 12+ hour) battery life. And as that phone ages, the battery life begins to wind down. By the time we’ve had the phone a few years, we’re reaching for that power bank or charger halfway through the day. It’s a predictable cycle.
Hot stuff baby this evening
What kills rechargeable batteries? It’s heat, charge cycles and to a lesser degree, time. All batteries will become inert over time. Their chemical makeup will change and they won’t hold a charge well at all. This process happens faster when you charge and recharge over and over. It’s the number of “charge cycles” that really matters. It doesn’t matter if you charge your phone 10% at a time, or if you drop it to practically zero and charge it up. (This wasn’t always true, before fancy battery management systems.)
But the biggest killer of batteries is heat. That’s not great considering the amount of time that our phones spend in our pockets. Electric cars have fancy cooling systems to extend the life of their battery packs, but that’s not really possible with your phone. Eventually, we’ll see improvements in this tech, because it’s so important to our lives. But it will take time.
Buried in single-use batteries
Unfortunately, there are still a lot of cases where single-use batteries are the best choice. Medical equipment must function very reliably, and single-use batteries are the right choice there. The same is true of smoke detectors and other critical detection systems. And that means eventually, that battery is used up and tossed away. Batteries aren’t really recyclable yet so they are treated as hazardous waste. Putting a used battery in the ground could pollute groundwater, so it’s not a good idea to just toss them in the trash.
And all of that means, in some way or another, pretty much every single-use battery ever made is still out there somewhere. It’s time we start thinking about that and what we can do about it, before we’re all buried in them.