The battery industry never used to care much whether the batteries actually lasted a long time. Of course the adverts always hinted that the batteries had extraordinary lifetimes, but reality told a different story. As a product, a battery is like a razor or a light bulb. The manufacturer wants it to satisfy expectations and then die the moment it does. Expectations are what the consumer gets used to, so batteries didn’t improve much for decades – it just wasn’t good for the balance sheet. Battery competition took place entirely within adverts. “Fluffy bunny toy beating drum gets captured by aliens” can mean only one thing: your non-rechargeable AA batteries are just as lame as they always were.

Life got more adventurous for the battery people when laptops, mobile phones, PDA’s etc. started to cover the surface of the Earth like a rash. First of all, rechargeable batteries, which had once been a curiosity that you could waste money on for no good reason, needed to be genuinely effective. They gradually became the dominant requirement. The form factor problem arose – batteries needed to be different shapes  and sizes – but more importantly, they needed to carry the right amount of charge for the device so they didn’t become an annoyance. Mobile phones dying mid-conversation and laptops giving out on airplane journeys were the defining problems.

The battery industry is now challenged in many ways, because it can’t simply produce billions of AA size cylinders, expect device manufacturers to design around that and watch the money roll in. In the last decade or so it has been investing heavily to try to improve its product. And it has got encouraging results in an incremental fashion. For example, it has managed to roughly double the range of an electric car in that time.

Batteries need to care about:

1. Weight and Form Factor: For vehicles particularly – no point in carrying extra weight in an electric vehicle. Also scalability (small batteries or large and any possible shape too).
2. Charge speed: Again, mostly for vehicles – you cannot wait around too long for your batteries to charge up.
3. Charge density: You can measure this in “watt hours per kilogram”. Lithium-ion delivers about 120 watt hours per kilogram, while lead-acid delivers only 32 watt hours per kilogram, which explains the interest of the auto industry in Lithium-ion, especially Lithium-ion that doesn’t catch fire.
4. Not catching fire.
5. Cost: There is a market in operation here, so battery technology based on scarce materials or complex fabrication is at an obvious disadvantage.
6. Recharge characteristics: Some batteries do better if you thoroughly drain them before recharge. Others do better if you only use a fraction of their stored power before recharge. Recharging degrades some battery technologies more than others. This dimension of a battery is itself a very complex field. For example there’s a big difference between a battery that can do, say 1000 recharges before it dies, but delivers near consistent capacity every time and one that can do 2000 recharges but its capacity degrades quickly so that after 500 recharges it’s capacity is halved.
7. Recyclability: Toxic waste is so “Bush era” and the world has moved past that.

I ran into a news story today about Silver Zinc batteries actually going into industrial production this year for use in laptops (click here to read). Apparently they cost more, but last 40% longer. In 2009, we should expect a high volume of news stories of this kind – in fact stories that span the gamut from “research scientists invent nano-batteries with 100x the normal capacity” to “XYZ Inc. brings new super battery to market” and maybe even “Apple announces iCharge.” I’ll be tracking this.

This time it’s not just the personal device market that cares about batteries, it’s the auto industry and, in fact, the whole of the transport world, plus the all the power utilities and the governments of most countries. This time it’s not just personal.