Battery

As of now battery life is a major constraint on the mobility of laptops. With average only battery life being only around 3-4 hours, that doesn’t give one that much time before the need to “plug in” arises. A student cannot attend a full day of classes without taking the time to recharge and a business person cannot work on their laptop for much of an overseas flight. As this aspect of mobile computing evolves and becomes more advanced so too will the level of mobility become more advanced.

History

When laptops were first developed they had little to no battery power and pretty much required an outlet to operate. They were considered mobile simply because one could unplug them, move them to another location, plug them back in, and then continue to use them.

Current

Unfortunately, the actual current batteries that are in widespread use for laptops do not employ a very advanced technology. It has actually been around for quite some time. Lithium Ion (Li-ion) batteries are the standard system used in today’s laptops. Currently, most Li-ion batteries can be fully charged in as little as 45 minutes and some can be charged up to 90% capacity in as little as 10 minutes. This is a stable technology, but it does have its drawbacks. Li-ion batteries tend to lose around 20% capacity each year. This is from the time they are manufactured therefore their shelf-life isn’t that long in terms of keeping a high level of performance. Every 100 cycles of full battery charge leaves it with 75% to 85% of its original capacity. This means that after three to five years the battery capacity is too low to be used.

Average battery lifetime after a full charge is around 3-4 hours now. There are some extreme laptops that are battery efficient or employ an extended battery that can run up to 7-8 hours, but with this kind of battery life you pay for it in performance.

The current trend in improving battery life is less focused on improving the battery system itself, but instead improving the power use efficiency of the laptop. Namely, the power consumption efficiency of the processor as this portion of the laptop consumes half the life of the battery on its own on average. This has been a major focus of chip-producing companies in the last couple of years.

Future

Companies are turning to the fuel-cell as the next generation laptop battery system. Supposedly, fuel-cell batteries will allow laptop computers to operate for as many as 40 consecutive hours. This is nearly 10 times the life of a common lithium-ion battery. Fuel-cell batteries will not use recharging like batteries do today. Instead, fuel-cell batteries will be recharge by refilling them with a fuel such as hydrogen gas or liquid methanol. If and when this technology comes into use it will create a whole new set of battery issues as societies have been built around the concept of powering and charging electronic devices with electricity from electrical outlets.