Week 1 Understanding Different Battery Chemistry

AIM :

1. Prepare a table that includes materials & chemical reactions occurring at the anode and cathode of LCO, LMO, NCA, NMC, LFP and LTO type of lithium-ion cells. Give your detailed explanation on it
2. Compare the differences between each type of Li-ion battery based on their characteristics.

QUESTION 1:

Prepare a table that includes materials & chemical reactions occurring at the anode and cathode of LCO, LMO, NCA, NMC, LFP and LTO type of lithium-ion cells. Give your detailed explanation on it.

ANSWER :

Introduction:

Lithium-ion Cells are a secondary type of battery cell that is they are rechargeable and also they are reusable which makes them ideally suited for automotive applications and certain consumer electronics When two or more cells connected they are referred to as batteries Like other batteries Lithium-ion batteries also rely on the chemical energy stored in the bonds and atoms of elements and compounds and utilize this energy in a chemical reaction occurring inside the cell. The chemical energy from this reaction is converted to electrical energy and it is used. Since the Lithium-ion cells are rechargeable, they can perform the reverse reaction using electricity as well.

Construction:

Electrolyte

• The electrolyte is an ionic conductor that provides the medium for internal ionic charge transfer between the electrodes
• The electrolyte must often comprise a liquid solvent containing dissolved chemicals the solution that provides the ionic conductivity
• The Lithium-ion cels use non-aqueous electrolytes

Cathode and Anode

• The Cathode ad Anoide is the two electrodes that are connected by a wire in an external circuit The electrons are passing through the external wire and so an electric current is perorated
• The Anode refers to the Electrode through which the conventional current enters into a polarized electrical device.
• The Cathode refers to the electrode through which conventional current leaves an electrical device.

Separator

• The Separator physically isolates the positive and negative electrodes. The separator is an ionic conductor but an electronic insulator
• It prevents the internal short-circuiting between the two electrodes

Current Collectors

The current collectors are the electronic conductors with which the electrodes are mixed It does not take part in chemical reactions of the cell but instead, it either allows simple electronic connection to reduce the electronic resistance of an electrode.

Advantages of Lithium Ion Battery :

Following are the benefits or advantages of Lithium-Ion batteries:

• It has a high energy density which is two times compare to Ni-Cd.
• The Lithium-Ion battery is rechargeable.
• There is no memory effect. Hence it is not needed to discharge them completely before recharging.
• The battery can handle many charge/discharge cycles.
• The battery can hold the charge and it can lose only 5% of its charge every month.

Disadvantages of Lithium-Ion Battery

Following are the disadvantages of Lithium-Ion Battery:

• It lasts only two to three years after the manufacturer.
• It is sensitive to high temperatures.
• If the battery is completely discharged, it can no longer be recharged again.
• It is relatively expensive.
• If the "separator" gets damaged, it can burst into flames.

Table :

Explanation:

Lithium Cobalt Oxide (LiCoO2) - LCO

Lithium Cobalt Oxide: LiCoO2 cathode (~60% Co),

graphite anode

Short form: LCO

Voltages

3.60V nominal; typical operating range 3.0 4.2V/cell

Specific energy (capacity)

150-200Wh/kg. Specialty cells provide up to 240Wh/kg.

Charge (C-rate)

0.7-1C, charges to 4.20V (most cells); 3h charge typical. Charge current above IC shortens battery life.

Discharge (C-rate)

1C; 2.50V cut off. Discharge current above 1C shortens battery life.

Cycle life

500-1000, related to depth of discharge, load, temperature

Thermal runaway

150°C (302°F). Full charge promotes thermal runaway

Applications

Mobile phones, tablets, laptops, cameras.

Lithium Manganese Oxide (LiMn204) - LMO

Lithium Manganese Oxide: LiMn2O4 cathode.

graphite anode

Short form: LMO

Voltages

3.70V (3.80V) nominal; typical operating range 3.0-4.2V/cell

Specific energy (capacity)

100-150Wh/kg

Charge (C-rate)

0.7-1C typical, 3C maximum, charges to 4.20V (most cells)

Discharge (C-rate)

1C; 10C possible with some cells, 30C pulse (5s), 2.50V cut-off

Cycle life

300-700 (related to depth of discharge, temperature)

Thermal runaway

250°C (482°F) typical. High charge promotes thermal runaway

Applications

Power tools, medical devices, electric powertrains

Lithium Nickel Manganese Cobalt Oxide (LiNiMnCoO2) - NMC

Lithium Nickel Manganese Cobalt Oxide: LiNiMnCoO2. cathode,

graphite anode

Short form: NMC

Voltages

3.60V, 3.70V nominal; typical operating range 3.0-4.2V/cell, or higher

Specific energy (capacity)

150-220Wh/kg

Charge (C-rate)

0.7-1C, charges to 4.20V, some go to 4.30V; 3h charge typical. Charge current above IC shortens battery life.

Discharge (C-rate)

1C; 2C possible on some cells; 2.50V cut-off

Cycle life

1000-2000 (related to depth of discharge, temperature)

Thermal runaway

210°C (410°F) typical. High charge promotes thermal runaway

Applications

E-bikes, medical devices, EVs, industrial

Lithium Iron Phosphate (LiFePO4) - LFP

Lithium Iron Phosphate: LiFePO4 cathode,

graphite anode

Short form: LFP

Voltages

3.20, 3.30V nominal; typical operating range 2.5-3.65V/cell

Specific energy (capacity)

90-120Wh/kg

Charge (C-rate)

1C typical, charges to 3.65V; 3h charge time typical

Discharge (C-rate)

IC, 25C on some cells; 40A pulse (2s); 2.50V cut off (lower that 2V causes damage)

Cycle life

2000 and higher (related to depth of discharge, temperature)

Thermal runaway

270°C (518°F) Very safe battery even if fully charged

Applications

Portable and stationary needing high load currents and endurance

Lithium Nickel Cobalt Aluminum Oxide (LINICOAIO2)- NCA

Lithium Nickel Cobalt Aluminum

Oxide: LINICOAIO2 cathode (~9% Co),

graphite anode

Short form: NCA or Li-aluminum.

Voltages

3.60V nominal; typical operating range 3.0-4.2V/cell

Specific energy (capacity)

200-260Wh/kg; 300Wh/kg predictable

Charge (C-rate)

0.7C, charges to 4.20V (most cells), 3h charge typical, fast charge possible with some cells

Discharge (C-rate)

1C typical; 3.00V cut-off; high discharge rate shortens battery life

Cycle life

500 (related to depth of discharge, temperature)

Thermal runaway

150°C (302°F) typical, High charge promotes thermal runaway

Applications

Medical devices, industrial, electric powertrain (Tesla)

Lithium Titanate (LI2TiO3) LTO

Lithium Titanate: Cathode can be lithium manganese oxide or NMC;

Li2Ti03 (titanate) anode

Short form: LTO.

Voltages

2.40V nominal; typical operating range 1.8-2.85V/cell

Specific energy (capacity)

50-80Wh/kg

Charge (C-rate)

1C typical; 5C maximum, charges to 2.85V

Discharge (C-rate)

10C possible, 30C 5s pulse; 1.80V cut-off on LCO/LTO

Cycle life

3,000-7,000

Thermal runaway

One of safest Li-ion batteries

Applications

UPS, electric powertrain (Mitsubishi i-MiEV, Honda Fit EV), solar-powered street lighting

QUESTION 2 :

Compare the differences between each type of Li-ion battery based on their characteristics.

Type of Batteries:

Comparison between Li-Ion batteries and their charecteristics: