Lithium Ion cells

Historically, lead-acid, nickel-cadmium (Ni-Cd), and nickel-metal hydride (Ni-MH) batteries have been the conventional choice for small-sized rechargeable batteries.Nowadays, rechargeable batteries are required to provide higher energy density to meet the needs of customers.

Moreover, the attention being focused on protecting the environment has resulted in demand for products that are environmentally friendly.

A. High Energy Density

The weight of a lithium ion battery is approximately one half compared to a nickel-cadmium or nickel-metal hydride battery of similar capacity. Moreover, the volume of the lithium ion battery is 40 to 50% smaller than that of a nickel-cadmium and 20 to 30% smaller than that of a nickel-metal hydride battery.

B. High Voltage

A single lithium ion cell has a voltage of 3.7V (mean value), which is equal to either three nickel-cadmium or nickel-metal hydride cells connected in series.

C. Pollution-free

The lithium ion battery does not contain any polluting substances such as cadmium, lead, mercury, etc.

D. Non-metal Lithium

The lithium ion battery does not employ any lithium metal. It is not governed by aircraft transportation rules relating to carrying lithium batteries in passenger airplanes.

E. Long Cycle Life

Under normal conditions, the lithium ion battery has a life of more than 500 charge/discharge cycles.

F. No Memory Effect

The lithium ion battery is free from the so-called memory effect, a phenomenon seen in nickel-cadmium in which the apparent battery capacity decreases when shallow charge and discharge cycles are repeated.

G. Fast Charge Capacity

The lithium ion battery can be fully charged in 1 to 2 hours, using a constant-current / constant-voltage (CC/CV) type dedicated charger with a rated voltage of 4.2V per cell.

The rechargeable lithium ion battery shows great promise as a battery to meet such requirement. This battery technology has excellent features, such as: high energy density, high voltage and cycle life characteristics. These batteries are widely used for High capacity multi-cell applications (e.g. electric bike, electric wheelchair, electric golf car, electric motor-cycle, electric car, etc.) High-rate discharge applications (e.g. power tools, e-scooter, electric golf car, electric motor-cycle, electric car, etc.)

Chemistry Comparison

- Lithium Cobalt (LiCoO2) - Lithium Manganese Oxide (LiMn2O4) - Lithium Nickel Manganese Cobalt (LiNiMnCoO2) - Lithium Ferrous Phosphate (LiFePO4)

Cell Chemistries LiCoO2 LiMn2O4 LiNiMnCoO2 LiFePO4 Rate Voltage 3.7V 3.8V 3.6V 3.2V Charging Voltage 4.2V 4.2V 4.2V 3.7V Dischargiing end Voltage 3.0V 2.5V 2.5V 2.0V Energy Density (Wh/L) 447 253 327 222 Energy Density (Wh/Kg) 140-145 105-115 140-155 90-110 Cycle Life >700 >500 >700 >1800 Self-Discharge Rate (Month) 1% 5% 1% 0.05% High Temperature Performance (55+/-2 ) Good Acceptable Good Excellent Low Temperature Performance (-20+/-2 ) Good Good Good Good High-rate Discharge (10C) N/A Good Good Excellent Safety & Environmental Concern Bad Good Good Excellent