Rechargeable batteries

We present here a brief overview of rechargeable batteries.

The consumer type is represented by cylinder Ni-MH type with voltage 1.2V. Often it is used instead of alkaline in spite of lower voltage. Ni-MH batteries also is used in some specific industrial applications. There are high power version (D-size cell provide current up to 150A), high temperature version (+90…+100℃), version with full industrial temperature range (-40…+85℃), version which can be charged at negative temperature, etc. Unlike lithium Ni-MH battery from several cells doesn’t need electronic protection and equilibrium circuit, simple fuse is enough. Main disadvantage – low energy density ~ 80 Wh/kg

New trend – lithium 1.5V rechargeable batteries with USB charging. Really battery consists of 3.7V li-ion cell and small PCB with DC/DC converter.

Li-ion batteries is divided on several types depends on cathode/anode material. From chemical point of view terms “Li-Ion” includes the following:

Li-Ion classification by chemistry

For our purposes it is better to classify “Li-Ion” by cell voltage.

“Li-Ion” classification by cell voltage

Chemistry Name, abbreviations Nominal voltage Voltage of 100% charged cell
{C} +NMC // NCA // LCO // LMO Li-ion “classic”
3.6 -3.7V 4.2– 4.4 V
{C} + LFP (Li-FePO4) Li-FePO4
3.2 - 3.3V 3.6 - 3.65 V
LTO + {LCO // LMO // NMC} Lithium-Titanate
2.3 – 2.4 V 2.7 - 2.8 V
Basic features of different Li-Ion types are in this table:

Features of “Li-Ion” types

Chemistry abbreviations Energy density Number of cycles charge/discharge Safety
NMC/NCA/LCO 200-300Wh/kg 500 –3000 Moderate
LFP 120-200 Wh/kg 1500 - 7000 Safe
LTO 80-90Wh/kg 10000 - 20000 Safe
Manifold of Li-Ion batteries allows to provide the most suitable for particular case solution. Sometimes it will better to use standardized 18650, 21700 and other cylinder cells. Sometimes the best solution will from prismatic or pouch cells.