Superb energy density
Looks can be misleading. Even though cylindrical cell shape is not the most efficient at filling the gaps, resulting size and weight still stands out from the crowd. 18650 cells are the pioneers in consumer portable devices, which forced them to become the most energy-dense solution available. These cells are still one of the most popular type in applications, where safety and energy density is the highest priority. The most energy-dense cells today are packing above 270 Wh/kg and can offer up to 10C discharge rates for power-hungry applications. In comparison to other "safe" (LiFePO4) chemistries, 18650 offers at least 2 times greater energy density or 2 times lower weight and volume.
The gaps between cells do not go as wasted space. They form air channels for precise thermal control, and are also used as an additional safety mechanism in case of venting.
There were many different approaches by large and reputable companies out there. After years of observations and research, we have concluded that a simple solution is the best. There were many attemps to create a new lithium cell, special in some way, and very often they turned out to be unsafe and unreliable. Even large commercial airplane companies have failed miserably while trying to implement untested battery solutions. Based on this experience of others, we are confident this is the best solution available today.
18650 is probably the most reliable cell type available today. Due to many years of mass production, very high safety and reliability requirements set by consumers, these cells show fail rates of only 0.01 ppm (1 in 100.000.000). While battery chemistry has been improving across the board, cylindrical lithium-ion cells remain the ones to be manufactured to the highest standard of quality of any available battery. In our battery packs, only genuine cells are used, and only from the top brands, such as Samsung, Panasonic, Sony and LG.
Passive safety mechanisms are built into each single 18650 cell. On top of safe chemistry, venting valve and disconnect mechanisms are implemented. Cells are designed to withstand the abuse of an uninformed consumer.
Furthermore, our module structure includes additional fusing on every single cell, as well as air channels for safe venting of gasses in case of a critical event. These techniques guarantee that each individual cell operates at specified conditions, and if there is a failure, it is isolated from the surrounding battery pack. A literally bullet-proof battery pack can be constructed.
On top of passive safety features provided by the cells and our unique battery design, we offer a smart Battery Management System. The BMS monitors all parameters of the battery in real time and controls them accordingly: temperature, voltage, current limits in various modes of operation are supervised and controlled, cells are balanced to identical state of charge to prolong battery life and operating time. All parameters are configurable and available via open serial communication protocol. The same protocol is used for statistical analysis, event review and live data streaming, as well as displaying data on our Android app. Free firmware updates are included as well.