Battery Chemistry
Lead-acid, Ni-CD, Ni-MH, Li-ion & Li-polymer batteries
Portable electronics such as notebooks, PDA, cell phone and digital cameras have gained worldwide popularity resulting in higher demand in device mobility in our everyday life. The need to have more power, longer life, and lighter solutions has led to the battery industry evolving a series of battery cells such as Lead-acid, nickel-cadmium (Ni-Cd), nickel-metal (Ni-MH), lithium-ion (Li-ion), and lithium ion polymer (Li-polymer). These newly developed batteries have vastly improve the mobility and usage time of electronic products by being more lightweight and by incorporating higher energy density.
There are numerous types of batteries that have different characteristics and applications. For portable electronic equipments, the main demand lies on lightweight, high energy density, long cycle life and ease of use. The most common secondary batteries are Lead-acid batteries, Ni-Cd batteries, Nh-MH batteries and Li-ion batteries. Except for Alkaline batteries (primary batteries), secondary batteries (rechargeable batteries) have become the main stream for portable electronic products.
The following table illustrates a comparison of the main categories of secondary batteries:
| Category |
Lead-acid |
Ni-Cd |
Ni-MH |
Li-ion |
Li-polymer |
| Nominal Voltage (V) |
2 |
1.2 |
1.2 |
3.6 or 3.7 |
3.6 |
| Positive electrode |
PbO2 |
NiOOH |
NiOOH |
LiCoO2 or LiMn204 |
LiCoO2 |
| Negative electrode |
Pb |
Cd |
Hydrogen, storage alloy |
Carbon |
Carbon |
| Electrolyte |
H2SO4 |
KOH |
KOH |
Organic solvent with LiPF6 |
Polymer gel |
| Charging Volt. Limit (V) |
x |
< 1.8 |
< 1.8 |
<= 4.2 |
<= 4.2 |
| Cut-off discharging volt (V) |
Depend on discharge rate |
0.8 ~ 1.0 |
1 |
2.7 ~ 3.0 |
2.7 ~ 3.0 |
| Protection Module |
Nil |
Nil |
Nil |
Yes |
Yes |
| Capable of high discharge rate |
1C * |
10 C |
2 ~ 3C |
1 ~ 1.5C |
1 ~ 1.5C |
| Capable of low discharge rate |
Excellent |
Excellent |
Excellent |
Excellent |
Excellent |
| Self-discharge at 20 C (%/day) |
0.1 |
1 |
1.5 |
0.3 ~ 0.6 |
0.3 ~ 0.6 |
| Cycle life (Times) |
200 ~ 400 |
200 ~ 500 |
> 500 |
> 500 |
> 500 |
| Trickle Charging |
Yes |
Yes |
No |
No |
No |
| Memory effect |
No |
Yes |
No ** |
No |
No |
| Charging method |
CC-CV |
CC |
CC |
CC-CV |
CC-CV |
| Charging temp. range (C) |
5 ~ 35 |
0 ~ 45 |
10 ~ 45 |
0 ~ 45 |
0 ~ 45 |
| Discharging temp. range (C) |
5 ~ 35 |
-10 ~ 60 |
-10 ~ 45 |
-10 ~ 60 |
-20 ~ 60 |
| Environment Issue |
Sulfuric acid solution may influence human health |
Cadmium is a serious pollutant |
Low pollutant |
Low pollutant |
Low pollutant |
| Package |
Plastic case |
Seal metal can |
Seal metal can |
Metal can Aluminum can |
Aluminum laminate pack |
| Shape |
Cube |
Cylindrical |
Cylindrical, Prismatic |
Cylindrical, Prismatic |
Prismatic |
| Price |
Low |
Low |
More expensive than Ni-Cd |
High |
The highest |
| Consideration for electronic products |
For low price products that require longer durability |
Apply to products that requires higher discharge current and rapid charging |
Apply to products that need greater battery capacity and easier charge/discharge |
The same as Ni-MH, and especially for light weighted products |
The same as Li-ion, and for products that require batteries of unique shape |
| Applications |
Lightings system, UPS, toys |
Power tools, cordless phone, camcorder, toys |
Notebook, electronic razor, PDA, DVD player, cellular phone |
Notebook, PDA, DVD player, digital camera, cellular phone |
Notebook, PDA, cellular phone |
* C-rate : indicates the rate for the charge/discharge a battery. For instance, 0.2C mean it would require 0.2 times of nominal capacity to charge/discharge the battery.
** Our Ni-MH batteries are made of highest quality materials, therefore, our batteries do not have memory effect. On the other hand, if the materials used to manufacture the cells are not of high quality, it may have some memory effects.