How to Choose the Types of Lithium ion Batteries
Lithium battery, this word appears in our eyes almost every day. Batteries are a very important industry materials, and lithium batteries is the most recognizable and promising battery technology which are widely used on the market, in another word, from the small GPS tracker to large grid energy storage station, lithium battery plays a very important role.
How many types of lithium batteries are commercially used? What are they?
The most common one we know is the Li-ion NCM, or NCA technology. The battery nominal voltage is 3.6V or 3.7V (according to different manufacturers’ definition), recharge voltage is 4.2V or 4.25V, and discharge end voltage is 2.75V. Li-ion NCM & NCA batteries has high energy density, which is most preferable in many application usage, let’s take the most standard cell for an example, 18650 cell, the diameter is 18mm, height is 65mm, within such a small dimension, the cell can provides more than 12Wh energy storage, that’s amazing, isn’t it? But the experts are not still not happy with it. With the technology improvement, this number is still increasing.
Although Li-ion NCM and NCA battery has extreme high energy density, but it’s cycle life is not the best. Here comes the LiFePO4 Battery. In testing lab condition, by 1C discharge rate, 100% depth of discharge, LiFePO4 cycle life can reach to more than 3000 cycles when the remain capacity keeps 80%. LiFePO4 is widely used in the applications which requires long serving life, but are not removable so frequently, because it’s heavier than Li-ion NCM batteries, let alone the NCA battery.
Technically, those two kinds of batteries are the most common lithium secondary batteries which are achievable on the market by now.
| Model | 18650-3.6V-1500mAh | 18650-3.6V-2200mAh | 18650-3.6V-2600mAh | 18650-3.6V-3200mAh | 18650-3.2V-1500mAh | 26650-3.6V-5000mAh | 26650-3.2V-3400mAh | 26650-3.2V-2300mAh |
|---|---|---|---|---|---|---|---|---|
| Chemistry | NCM | NCM | NCM | NCM | LiFePO4 | NCM | LiFePO4 | LiFePO4 |
| Nominal Voltage | 3.6V | 3.6V | 3.65V | 3.6V | 3.2V | 3.6V | 3.2V | 3.2V |
| Recharge Voltage | 4.2V | 4.2V | 4.2V | 4.2V | 3.65V | 4.2V | 3.65V | 3.65V |
| Discharge End Voltage | 2.5V | 2.75V | 2.75V | 2.5V | 2.5V | 2.75V | 2.5V | 2.5V |
| Rated Capacity | 1500mAh(0.2C) | 2200mAh (0.5C) | 2600mAh (0.2C) | 3180mAh(0.2C) | 1500mAh(0.5C) | 5000mAh(0.5C) | 3400mAh(0.5C) | 2300mAh(0.5C) |
| Minimum Capacity | 1450mAh(0.2C) | 2150mAh (0.5C) | / | 3000mAh(0.2C) | 1450mAh(0.5C) | 4900mAh(0.5C) | 3300mAh(0.5C) | 2200mAh(0.6C) |
| Resistance | ≤ 25mΩ | ≤ 20mΩ | ≤ 40mΩ | ≤ 35mΩ | ≤ 40mΩ | ≤ 20 mΩ | ≤ 30mΩ | ≤ 12mΩ |
| Max. Charging Current | 4A | 4.4A | 1.3A | 1.5A | 1.5A | 5A | 3.4A | 11.5A |
| Standard Discharge Current | 4.4A | 2.6A | / | 0.75A | 5A | 1.7A | 11.5A | |
| Max. Continuous Discharge Current | 23A | 17.6A | 7.8A | 10A | 4.5A | 15A | 10.2A | 46A |
| Pulse Discharge Current | 33A (5s) | / | / | 10A (5s) | 15A(5s) | 70A (10s) | ||
| Cycle Life | 250 cycles | 800 cycles | 1000 cycles | >300 cycles | 2000 cycles | 500 cycles | 2000 cycles | 300 cycles |
| 100% DOD | 100%DOD | 100%DOD | 100%DOD | 100%DOD | 100%DOD | 100%DOD | ||
| 0.5C Recharge | 1C Recharge | 0.5C Recharge | 0.5C Recharge | 0.5C Recharge | 0.5C Recharge | 1C Recharge | ||
| 23A Discharge | 3C Discharge | 1C Discharge | 1C Discharge | 0.5C Discharge | 1C Discharge | 10C Discharge | ||
| 60% Remain | 70% Remain | 80% Remain | 70% Remain | 70% Remain | 70% Remain | 70% Remain | ||
| Working Temperature | Charge:0°C~50°C | Charge:0°C~55°C | Charge:0°C~45°C | Charge:0°C~45°C | Charge:0°C~55°C | Charge:0°C~45°C | Charge:0°C~55°C | Charge:0°C~55°C |
| Discharge:-20°C~60°C | Discharge:-20°C~60°C | Discharge:-20°C~60°C | Discharge:-20°C~60°C | Discharge:-20°C~60°C | Discharge:-20°C~60°C | Discharge:-20°C~60°C | Discharge:-20°C~60°C | |
| Battery Energy(Wh) | 5.4 | 7.92 | 9.49 | 11.448 | 4.8 | 18 | 10.88 | 7.36 |
| Battery Weight | 45g (Max) | 44g(Approx.) | ≤ 46g | ≤ 49g | 41g(Approx.) | About 95g | 87g(Approx.) | 85g(Approx.) |
| Weight Energy Density (Wh/kg) | 120 | 180 | 206.30 | 233.63 | 117.07 | 189.47 | 125.06 | 86.59 |
| Battery Size | 18.15(Dia)*64.85(H)mm | 18.4(Dia)*65.3(H)mm | 18.45(Dia)*65.05(H)mm | 18.5(*Dia)*65.3(H)mm | 18.15(Dia)*65.2(H)mm | 26.9(Dia)*65.5(H)mm | 26.15(Dia)*65.6(H)mm | 26.15(Dia)*65.6(H)mm |
| Battery Volume Density(Wh/L) | 80.50 | 114.09 | 134.62 | 163.13 | 68.50 | 120.95 | 77.24 | 52.25 |
| Price for Reference | 1.6 | 1.6 | 1.7 | 2.8 | 1.3 | 3.2 | 2.9 | 3.2 |
Those are some very common cells are seen on the market. From the specification, you will see the differences:
Li-ion NCM 3.6V cells has higher energy density then LiFePO4, in another words, Li-ion is smaller and lighter compared to LiFePO4 Battery.
LiFePO4 has 2 to 4 times cycle life compared to Li-ion.
Li-ion is cheaper than LiFePO4.
Higher Rate cells are expensive than normal discharge rate cells.
- High rate cells has short cycle life when discharge at high rate currents.