It has been a couple of decades since the commercial debut of rechargeable lithium-ion batteries, and today they dominate the market as the top choice for portable power. G.N. Lewis pioneered work on these batteries as early as 1912 as a means of overcoming the inherent instability of highly reactive lithium metal. The lithium-ion battery boasts several advantages – such as durability and eco-friendliness – though it does have its share of disadvantages.
The lithium-ion battery’s high energy density is perhaps its biggest edge over other rechargeables. By weight and by volume, it trumps the competition, storing as much as 150 watt-hours of energy in a single kilogram. Nickel-metal hydride (NiMH) battery packs, on the other hand, store only 60 to 70 watt-hours per kilogram, peaking at a comparatively low 100. Lead-acid batteries fare even worse, storing 25 watt-hours per kilogram – a mere one-sixth of the lithium-ion battery’s capacity. With respect to energy density, the lithium-ion battery is unquestionably the pound-for-pound champion.
Low Self-Discharge Rate
While a NiMH or a nickel-cadmium (NiCd) battery loses as much as 20 percent of its charge in a month, a lithium-ion battery loses around 5 percent, making it the perfect choice for travelers carrying electronic equipment. Prolonged storage, however, requires that the lithium-ion battery hold at least a 40 percent charge; storing a fully depleted battery cuts down on its overall life span significantly. Storage temperatures as low as -4 degrees Fahrenheit work best for extended periods, though newer lithium-ion battery packs function well after prolonged storage at room temperature.
The cost of the average lithium-ion battery often exceeds that of NiMH and NiCd batteries of the same capacity. For safe operation, manufacturers equip lithium-ion battery packs with a protection circuit, which limits the cell’s voltage during charging and discharging to a specified safe range. The complexity involved in manufacturing this circuit translates to the added cost. However, in spite of the higher initial costs, the lithium-ion battery’s power output over time makes it ultimately more economical than other rechargeable and disposable batteries. The life span of a typical lithium-ion battery extends to about two to three years.
Size- and Charger-Specific
There is currently no such thing as a universal lithium-ion battery; manufacturers design them to fit specific devices. Unlike NiMH and NiCd batteries, lithium-ion batteries do not come in standard cell sizes such as AA, C and D. Also, as a complete discharge or an overcharge damages or shortens the life of a lithium-ion battery, their chargers also come with sophisticated circuitry and are therefore more expensive.
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Steve Johnson is an avid and passionate writer with more than five years of experience. He's written for several industries, including health, dating and Internet marketing, as well as for various websites. He holds a bachelor's degree from the University of Texas.
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