The limits of batteries, and how they will improve

I was recently asked a question about battery life in modern devices, and coincidentally I’ve been reading a few articles about interesting developments in battery technology. So here’s a post giving a very superficial introduction to batteries in modern consumer electronics.

Technology is being held back because we can’t make better batteries. Ten years ago a mobile phone handset might have lasted a week on a full charge, while your new smartphone doesn’t even last an entire day; this is because your phone is capable of doing so much more thanks to the fact that everything about it has got smaller and more powerful in recent years – except for the battery.

The general principle is that the bigger a battery is, the more charge it holds. That’s why your tablet can keep a charge for days, whereas your phone needs a daily charge. But phones have a limit imposed by their portability – carrying a heavy battery around would make it longer-lasting, but much less useful.

The Lithium-ion battery, invented in 1991 and used in the majority of portable consumer electronics, is about as good as it gets at the moment. Even Tesla’s cars (and recently announced home battery) run on Li-ion batteries, albeit thousands of them in a larger battery case.

Manufacturers are getting very good at squeezing performance increases from Li-ion, but major improvements aren’t happening. The next step is not to make Li-ion batteries better, but to make them cheaper. Tesla are building a huge new factory that will more than double worldwide production of Li-ion, and although all of those will go into their own products, the net effect should be cheaper batteries overall (they estimate a 30% reduction). New startup 24M have also announced that they’ve reinvented the manufacturing process to cut development time by 80%, and costs by 50% (they claim performance benefits too, but these have yet to be quantified).

A promising new entrant to the arena is Sakti3, who claim to have invented a new solid state battery that can store twice as much energy as the Li-ion. The battery is currently only at prototype stage, but they recently received a large investment from Dyson to bring it into production.

In any case, it will take a few years for these new developments to come to market, so don’t expect your smartphone to get cheaper, lighter, or to hold a charge longer, any time in the near future.


Also published on Medium.