Laptop battery

A Basic Overview of Laptop Batteries Like all electronic batteries, a laptop battery provides power to the computer when the user does not have access to a power outlet. Laptop batteries, like most batteries used in portable devices, are rechargeable. Currently, most laptop manufacturers utilize lithium ion batteries, while some newer models use more advanced lithium polymer batteries. These technologies have largely replaced older nickel-metal hydride batteries, as newer technologies provide more efficient energy usage and longer lifespans. Most modern laptop batteries hold a charge for between two and five hours of light-duty use, though that number can drop to less than an hour for power-intensive tasks. In addition, laptop batteries gradually lose charge capacity over time, which eventually leads to their replacement. Depending on how a particular battery is charged and discharged, it may last for between one and three years. Differences Between Battery Types The three main types of batteries used in modern laptops are nickel-metal hydride (NiMH), lithium ion (Li-ion), and lithium polymer (LiPo) batteries. NiMH batteries are the oldest technology currently in use, while LiPo batteries represent the cutting edge of portable power supply technology. Each of these battery types has advantages and disadvantages, which consumers must take into account when selecting which type will best meet their particular needs. Nickel-Metal Hydride Batteries Commercial-size NiMH batteries first appeared on the market in the late 1980s, replacing the less-efficient and potentially toxic nickel-cadmium batteries. NiMH batteries provide an inexpensive and efficient alternative to standard alkaline batteries. In addition, NiMH batteries offer smoother discharge rates and more efficient power transfer during high current drain applications, such as portable computing. However, NiMH batteries do have a high rate of self-discharge, sometimes as much as 3 percent per day. While this is not an issue for most computer users, it can prove a problem if a fully charged battery is stored for a significant amount of time between uses. Lithium Ion Batteries Li-ion batteries began to see widespread use in the mid-1990s, as they provide a significant increase in total charge capacity over NiMH batteries. Li-ion batteries also proved to be lighter than comparable NiMH batteries, in addition to suffering significantly less self-discharge. Where a NiMH might automatically discharge up to 30 percent of its power in a month of non-use, a similar Li-ion would only lose between 10 and 15 percent of its total power. However, Li-ion batteries do have a few serious flaws. Li-ions are prone to steep drops in total charge capacity over time, as deposits build up within the electrolyte, which inhibits ion transfer. In addition, high charge levels and elevated temperature result in a permanent loss of charge capacity, with up to 20 percent of the battery's capacity lost if consistently kept at full charge and 77 degrees Fahrenheit. Lastly, some Li-ion batteries, especially those based on lithium cobalt oxide, can suffer thermal runaway and cell rupture if overheated or overcharged. In the most severe cases, this can lead to catastrophic failure, including the ignition of the chemicals inside the battery. Lithium Polymer Batteries LiPo batteries are an outgrowth of Li-ion technology. Instead of holding the lithium-salt electrolyte in an organic solvent, LiPo batteries use a solid polymer composite. This allows for a lower cost of manufacture, wider adaptability, and increased reliability and ruggedness. Their adaptability in particular has led to their adoption in small-scale consumer electronics, including products by Apple and Sony. However, LiPo batteries also run the risk of explosion if they are not charged properly or if the battery short-circuits. In addition, delamination can occur at high states of charge, which necessitates a strong casing to ensure the polymer retains its shape. How to Make a Battery More Efficient Regardless of the type of battery a laptop users, there are several steps consumers can take to extend both the charge capacity and overall lifespan of a battery. While some of these steps are relatively simple and straightforward, some more serious steps can significantly increase a battery's potential.