Week 1 Understanding Different Battery Chemistry

Answer 1) The Lithium-ion battery is divided into 6 groups:

• LCO-Lithium Cobalt Oxide (LiCoO₂):

First developed by Sony in 1991. It has a high specific energy. The cathode used is cobalt oxide and the anode is graphite carbon. During discharge lithium ions move from the anode to the cathode and vice versa for charging. Li-cobalt should not be charged and discharged at a current higher than its C-rating. These are commonly used for mobile phones, laptops and digital cameras.

Advantages:

• High energy density
• Long runtime making it optimum for new technologies

Disadvantages:

• Relatively short life span
• low thermal stability
• limited load capabilities (specific power)

Nominal Voltage	3.60V
Maximum Voltage	4.2 V
Cutoff voltage	2.50 V
Specific energy (capacity)	150–200Wh/kg
Charge (C-rate)	0.7–1C
Discharge (C-rate)	1C; 2.50V cut off
Cycle life	500–1000, related to the depth of discharge, load, temperature
Thermal runaway	150°C Full charge promotes thermal runaway

• LMO-Lithium Manganese Oxide (LiMn₂O₄)

Lithium manganese oxide batteries (LMO) were first introduced in the early 1980s. It is a lithium-ion cell that uses manganese dioxide, MnO₂, as the cathode material. They function on the same intercalation/de-intercalation mechanism as other commercialized secondary battery technologies, such as LiCoO₂. Li-manganese is used for power tools, medical instruments, as well as hybrid and electric vehicles.

Advantages:

• Low internal cell resistance enables fast charging and high-current discharging
• High thermal stability
• Enhanced safety

Disadvantages:

• Cycle and calendar life is limited
• limited load capabilities (specific power)

Nominal Voltage	3.70-3.80V
Maximum Voltage	4.2 V
Cutoff voltage	2.50 V
Specific energy (capacity)	100–150Wh/kg
Charge (C-rate)	0.7–1C
Discharge (C-rate)	1C, 10C possible for few cells; 2.50V cut off
Cycle life	300-700, related to the depth of discharge, temperature
Thermal runaway	250°C High charge promotes thermal runaway

• NMC-Lithium Nickel Manganese Cobalt Oxide (LiNiMnCoO2)

They are mixed metal oxides of lithium, nickel, manganese and cobalt. They have the general formula LiNi_xMn_yCo_zO₂. The most important representatives have a composition with x + y + z that is near 1, with a small amount of lithium on the transition metal site. This means the cathode combination is typically one-third nickel, one-third manganese, and one-third cobalt. These are used for providing high energy and power. NMC batteries are found in most electric cars. NMC batteries were installed in the BMW. It is very popular for EV applications.

Advantages:

• High specific energy and power
• Enhanced safety
• Longer lifecycle

Disadvantages:

• Costly

Nominal Voltage	3.70-3.70V
Maximum Voltage	4.2 V
Cutoff voltage	2.50 V
Specific energy (capacity)	150–220Wh/kg
Charge (C-rate)	0.7–1C
Discharge (C-rate)	1-2C; 2.50V cut off
Cycle life	1000-2000 related to the depth of discharge, temperature
Thermal runaway	210°C High charge promotes thermal runaway

• LFP-Lithium Iron Phosphate (LiFePO₄)

It is a type of lithium-ion battery using lithium iron phosphate (LiFePO₄) as the cathode material and a graphitic as carbon electrode as the anode. The energy density of LiFePO₄ is lower than that of lithium cobalt oxide (LiCoO₂), and also has a lower operating voltage. Li-phosphate is more tolerant to full charge conditions and is often used to replace the lead-acid starter battery. It is used for Portable and stationary applications needing high load currents and endurance.

Advantages:

• High current rating
• Long cycle life
• High thermal stability
• Enhanced safety
• Tolerance to abuse usage

Disadvantages:

• Higher self-discharge
• Low voltage

Nominal Voltage	3.20-3.30V
Maximum Voltage	3.65 V
Cutoff voltage	2.50 V
Specific energy (capacity)	90–120Wh/kg
Charge (C-rate)	1C
Discharge (C-rate)	1C; 2.50V cut off
Cycle life	>2000, related to the depth of discharge, temperature
Thermal runaway	270°C Very safe battery even if fully charged

• NCA-Lithium Nickel Cobalt Aluminium Oxide (LiNiCoAlO₂)

NCAs are mixed oxides comprising the cations of the chemical elements lithium, nickel, cobalt and aluminium. The most important representatives have the general formula LiNi_xCo_yAlzO₂ with x + y + z = 1. These batteries share similar properties as NMC batteries as they both have high specific energy, reasonably good specific power and a long-life span. But these NCA batteries are of high cost and less safe for applications.

Advantages:

• High specific energy
• High specific power
• Good life span

Disadvantages:

• High cost
• Less safe

Nominal Voltage	3.60V
Maximum Voltage	4.20V
Cutoff voltage	3.00 V
Specific energy (capacity)	200-260Wh/kg
Charge (C-rate)	1C
Discharge (C-rate)	1C; 3.00V cut off
Cycle life	500, related to the depth of discharge and temperature
Thermal runaway	150°C High charge promotes thermal runaway

• LTO- Lithium Titanate (Li₂TiO₃)

This battery chemistry was synthesized by solid-state reaction with Li₂CO₃ and TiO₂ powder. Lithium titanate is the anode component of the fast-recharging lithium-titanate battery. It is frequently utilized as a flux due to its good stability. Li-titanate is safe, has excellent low-temperature discharge characteristics. These are typical used for application in electric vehicles, UPS and solar-powered street lighting.

Advantages:

• No SEI film formation and no lithium plating
• High performance
• long life span

Disadvantages:

• High cost
• Low cell voltage
• Low specific energy and power

Nominal Voltage	2.40V
Maximum Voltage	2.850V
Cut-off voltage	1.80 V
Specific energy (capacity)	50-80Wh/kg
Charge (C-rate)	1C-5C
Discharge (C-rate)	1-10C; 1.80V cut off
Cycle life	300-7000
Thermal runaway	One of the safest Li-ion batteries

Answer2) The table below compares all lithium-ion chemistry on 6 characteristics

Sr No.	Battery chemistry	Specific energy	Specific power	Safety	Performance	Life	cost
1	LCO	5	3	3	4	3	4
2	LMO	4	4	4	3	3	4
3	NMC	5	4	4	4	4	4
4	LFP	3	4	5	4	5	4
5	NCA	5	5	3	4	5	3
6	LTO	3	4	5	5	5	2

Reference:

1) https://batteryuniversity.com/learn/article/types_of_lithium_ion

2) Simulation of Battery Systems: Fundamentals and Applications by Farschad Torabi and Pouria Ahmadi