Lithium-ion cells (Li-ion batteries)

Lithium-ion cells are the future of powering portable and wireless electronics – they are found in smartphones, MP3 players, remote-controlled models, etc. Their characteristic features are usually small dimensions and flat or cylindrical shapes. These unassuming cells can store twice as much energy compared to Ni-MH batteries of the same size.


Popular universal Li-ion batteries are 18650 cylindrical cells, which can be found in many consumer devices powered by single cells (such as e-cigarettes, flashlights) or in the form of closed packs (power banks, batteries for power tools, laptops, or electric bicycles). They are even used to power Tesla electric sports cars and energy storage for renewable sources, where the number of batteries in one pack often exceeds several thousand units. However, there are several important aspects compared to popular nickel-metal hydride batteries that every user of these cells should know.

Li-ion batteries have three times higher nominal voltage compared to Ni-MH cells (about 3.4-3.7 V), but they are also significantly more expensive to produce. They have a higher energy density, which makes them smaller and much lighter than their nickel-metal hydride counterparts. Like Ni-MH batteries, they feature a very flat discharge characteristic.
They also have a low self-discharge rate not exceeding 3-5% per month and greater reliability.

The device must be adapted to Li-ion batteries – they are not a direct replacement for Ni-MH batteries or alkaline batteries. Li-ion batteries can be divided into protected batteries (such a battery has an integrated electronic circuit that protects the cell from improper use) and unprotected (such cells are very 'delicate', the discharge and charging process of such a cell must be monitored very carefully, and they must be particularly protected from short circuits).

Considering the requirement for special treatment of 18650 cells, they should be charged in high-quality processor chargers from reputable manufacturers. The most advanced representative of chargers designed for charging 18650 cells is the everActive LC-2100, which allows for optimal, safe, and automatic charging of 1-2 cells. It has two independent charging channels and the ability to select the current with which the specific cells are charged. Additionally, the LC-2100 charger has a capacity test (discharge) and a unique internal resistance test, which allow for a precise assessment of the condition of each individual cell and determine its appropriate application.

The batteries themselves should also be chosen rationally. We recommend selecting cells only from verified manufacturers with a solid market position. One of the initial criteria for assessing battery quality can be its capacity. Here, as with Ni-MH cells, one can encounter the unfair practice of significantly (even by 1000%!) inflating the capacity value stated on the battery label/packaging. It should be noted that the maximum technologically achievable capacity in the most expensive Japanese 18650 cells is about 3500 mAh.
However, the most popular are cells with a capacity of 2000-2600 mAh – even these will be a significantly better choice than purchasing a "bargain" battery with an incredibly high capacity. Such batteries are often offered as 4000-10000 mAh, but in reality, they exhibit capacities no higher than 1000 mAh. They are potentially dangerous to use. When buying such uncertain cells, one must also consider the fact that they are often not brand new – they may come from the disassembly of used batteries, e.g., from laptops. Copyright © Baltrade