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Learn more: What is an 18650 battery?

Why are lithium-ion batteries important?

The world is shifting away from fossil fuels and will one day become fully electric.

Every time the world has harnessed a new generation of energy, be it fire, steam, or diesel, there have been fundamental and broad-stretching improvements to our lives. Battery Bro believes electrical energy stored in batteries will have great implications to the world in the next twenty years as technologies like electric vehicles, smart homes, robotics, and solar power collection are able to reach their full energy potentials.

Lithium-ion is the most promising chemistry of all batteries. Li-ion manufacturers have a regular cycle of improvements, and goals to reach energy density needed for full-adoption seem achievable. Large investments like Tesla’s Gigafactory act as evidence asserting their role as the next generation of batteries to revolutionize energy storage.

Shape Thin, flat sheets of metals comprising the anodes and cathodes of the cell are stacked one on the other, and rolled very tightly together like a jelly-roll. Lithium ions move between these layers, in one direction when the battery is charging, and in the opposite direction when it is discharging. The tight roll of anodes and cathodes is then jammed into a hard steel cylinder with an open top, and finally capped with the positive pole and sealed. Lithium polymer, or li-po cells on the other hand can be different shapes and are soft and shapeable. Size The 18650 (18mm by 65mm) battery is a size classification of lithium-ion batteries. If you have ever held one in your hand, you probably noticed it is the same shape, but a bit larger than a AA battery. AA batteries by comparison are sometimes called 14500 batteries, because they have a 14mm diameter and 50mm height. Cylindrical lithium-ion batteries all follow the same nomenclature, their name being determined by their size (diameter, followed by height). Specifications The two most important specs for 18650 cells are capacity measured in mAh (milliamp hours) and maximum continuous discharge measured in A (amperes). When selecting a battery type you must favor one over the other. High-capacity batteries have a low max. continuous discharge and high-amp batteries have a low capacity. Typical highest-capacity batteries in 2015 are ~3500mAh, and highest-amp batteries are 30A. Counterfeits Counterfeit cells are a growing problem, especially prevalent are those from Mainland China and Malaysia where the methods and markets for fake batteries have matured. These batteries often are dangerous and marked with exaggerated specifications. Many used batteries are rewrapped as new and white-labeled. Anti-counterfeiting measures like quality control, and supply-chain inspections are very important for retailers or manufacturers to ensure safety for end-users. Economy Over 40% of the world’s batteries are lithium-ion. The 18650 battery is one of the most widely produced lithium-ion battery types as it is found in laptops, power-tools, robots, electric vehicles, vaporizers, solar grids, and almost any application you can think of that desires to store electrical energy more efficiently. The cost to manufacture an 18650 has dropped from $10 for ~1500mAh (twenty years ago) to $2 for ~ 3000mAh (today). As cost per kilowatt hour continues to drop, new applications are able to use the technology - fueling demand and economies of scale.