What's the Big Deal About Lithium-Ion?

Some families have been so powerful, so influential, that they've gone on to change the world.

The Zhu family produced the Emperors of the Ming Dynasty, a ruling body that governed China for centuries and produced one of the greatest eras of orderly government and social stability in human history. The Zhu family, and its Emperors, build the Great Wall of China and the Grand Canal and changed the East forever.

The Mèdici family was a powerful and influential Florentine family from the 13th to 17th century. The family had three popes, numerous rulers of Florence, and later members of the French and English royalty.

There were some estimates that put the Mèdici family as the wealthiest and most powerful in Europe.

And then we have the Rothschild family, sometimes referred to simply as 'The Rothschilds'. Nathan Mayer Rothschild started his London business, N. M. Rothschild and Sons in 1811 at New Court in St Swithin’s Lane, City of London, where it still trades today. In 1818, he arranged a £5 million loan to the Prussian government, and the issuing of bonds for government loans formed a mainstay of his bank’s business.

However, there's not a jot of historical - or anecdotal - evidence to suggest that anyone in any of these families used power tools.

Shocking.

That being said, there's one family that has got strong ties to power tools, and it's this family that we place above all others in terms of changing the world.

The world of power tools.

Lithium-ion is a family of rechargeable battery types boasting one of the best energy densities, no memory effect, and a slow loss of charge when not in use.

That makes it absolutely perfect for our power tools.

But what about some of the terminology and technology within and associated with this family?

Let's break it down a bit.

Memory effect. No, we're not talking about that dull moment of wonder where you wake up on a Sunday morning and have no clue how you got there. Memory effect is the problem that (it's alleged) nickel cadmium rechargeables have whereby they hold less and less charge, depending on use.

For example, if a ni-cad battery is charged without being fully discharged, the theory goes that the battery "remembers" that it's got a smaller capacity for charge than the manufacturer intended.

This means your ni-cad battery will be less and less efficient, charge-by-charge. That's "memory effect".

Not so with lithium-ion batteries.

You can drop them on the charger no matter what their current state of discharge, and they'll eat until they're completely full again.

They also tend to charge faster and have greater life-spans than, say, ni-cad batteries. For example, Makita claim that they can achieve a "massive 2000+ cycles" from their lithium-ion batteries because of their Optimum Charging System.

That's a lot of tea break power ups.

Another advantage of lithium-ion batteries is their self-discharge rate. No, we're not talking about another post-Saturday-night-on-the-tiles phenomenon. Rather, rechargeable batteries slowly release their charge. This happens over time when their not put to use.

So, for example, you leave your Bosch GSR10.8-2-LI 10.8V drill driver in the van for two weeks over Christmas. The battery still has a fair bit of charge left in it. When you get back to the job site after the New Year you'll still be able to use the tool because the lithium-ion batteries will have held on to most of the charge you left them with.

It's estimated that lithium-ion rechargeables will self-discharge about 5-10% of their charge per month, compared to around 30% per month on ni-cads.

Perfect for those of us who forget to slap our tools onto the charger at the end of the day...

Weight a minute...

Operator fatigue is a pest, correct? When we're using a heavy corded power tool repeatedly throughout an 8 hour day on the job site we end up knackered. We then work slower. And we get paid less.

Being able to work quickly without that fatigue in our hands, wrists, arms, shoulders and backs is important and this is where our favourite family of rechargeables once again has changed the world of power tools.

Lithium-ion batteries are, traditionally, lighter.

For example, an 18v lithium-ion battery will weigh the same as a 12v Ni-MH.

Think that through; more power, less weight.

This is a breakthrough in the world of power tools that has, whether or not we've realised it, changed the way we're able to work. Less operator fatigue for more power. Bonuses all round.

Choosing a cordless power tool in 2011 will likely mean you'll be coming under the family influence of lithium-ion.

So, choose your manufacturer carefully, as each of the big brands has it's own "flavour" of lithium-ion rechargeable battery and associated technology.

Keep it cool...

Of course, efficiency of battery is vital, and we've already seen how the lithium-ion family are leaner in size, more dependable in the charge, but what about staying cool "under the collar"?

Heat is the enemy of batteries, so managing the through-put of heat generated within a rechargeable battery pack is very important. The hotter a battery gets, the shorter it'll live.

To enable each cell in the battery to be cooled, the unit needs to be designed in such a way that air flow around the battery is maximised.

For example, Makita have engineered their LXT lithium-ion batteries in such a way as to keep them at a cool temperature while charging.

They claim that their battery pack design "allows each cell to be kept at an optimum temperature which extends the battery life".

Bosch claim that their Premium Lithium-Ion technology provides a "400% longer lifetime" for the battery. This is due to the engineering of their units using Electronic Cell Protection. ECP constantly monitors the cells of the battery, stepping in to prevent overheating, but also overload and total discharge.

Bosch also claims that their lithium-ion batteries can be dropped from 2m onto concrete  and remain fully operational.

Our friends at Metabo have consistently impressed us with their lithium-ion battery technology, and they even offer a 3 year warranty on their batteries, which is pretty much unheard of in the industry.

They're so confident in the performance of their family of lithium-ion batteries due to their Electronic Single Cell Protection technology.

We've discussed this before, but to summarise, Metabo have created a battery management system to make sure you get the best from your lithium-ion battery.

For example, ESCP monitors each individual cell and status while working and charging. Plus, their chargers are fan cooled. This means the lithium-ion cools quickly and feeds quickly, all at the same time.

Metabo boasts that they "only use the highest grade lithium-ion cells available, with the highest power density ratings".

It's pretty clear that the manufacturers are taking your investment in lithium-ion technology seriously.

We consistently witness, whenever we visit their UK premises, that they're investing in R&D to squeeze even more power and durability into smaller and smaller battery packs.

There's no doubt that lithium-ion battery technology is evolving how we use power tools. Gone are the days where we needed to be close to a power point and tethered to an electrical cord in order to drill through a concrete wall.

Now we're going cordless, but we're doing so with power tools that are lighter, more efficient, more reliable, longer-lasting and more powerful than ever before.

And it's all thanks to that family of influence; lithium-ion rechargeable batteries.

So, how has lithium-ion changed the way you work? Let us know in the comments.