Test

Question 1

What is the role of batteries in the green shift?

Answer 1

Key ways:
Energy storage
Grid stabilisation
Electrification of transportation
Distributed energy systems
Support for off grid and microgrid solutions
Circular economy and sustainability

Question 2

What is the history of batteries?

Answer 2

1800- The Voltaic Pile
1836 - Daniell Cell
1859 - Lead-Acid Battery
1899 - Nickel-Cadmium Batteries (NiCd)
1950 - Alkaline Batteries
1970 - Lithium Batteries

Question 3

What are the most common battery types?

Answer 3

1. Lead - Acid Batteries (Automotive Starters)
2. Nickel - Cadmium Batteries (NiCd) (Power tools)
3. Nickel - Metal Hydride batteries (NiMH) (Consumer Electronics)
4. Lithium - Ion Batteries (Li-ion) (Portable Electronics)

Question 4

How does a battery work?

Answer 4

Batteries convert chemical energy into electrical energy through electrochemical reactions. Each battery consist of one or more electrochemical cells, each containing two electrodes (ANODE and CATHODE) separated by an electrolyte.

Question 5

What is the working principle of a LiB?

Answer 5

The lithium ions move between the cathode and anode during charge and discharge cycles.

Charging - External power source applies a voltage greater than the battery’s current voltage, forcing lithium ions to move from the cathode to anode.

Discharging- The stored lithium ions at the anode are released back into the electrolyte and move towards the cathode.

Question 6

What are the key materials used to store lithium in LiBs?

Answer 6

Cathode materials:
Lithium Cobalt Oxide
Lithium Iron Phosphate
Lithium Manganese Oxide
Lithium Nickel Manganese Cobalt Oxide
Lithium Nickel Cobalt Aluminium Oxide

Anode materials:
Graphite
Lithium Titanate
Silicon

Electrolyte - Typical Lithium salt dissolved in organic solvent
Separator - A porous membrane

Question 7

What materials are used as current collectors? Why?

Answer 7

For the Cathode
Aluminium (AI)

For the Anode
Copper (Cu)

Why?
High electrical conductivity
Chemical stability
Mechanical Properties
Cost and Availability

Question 8

What materials are used as electrolyte components? Why?

Answer 8

Lithium salts
Lithium Hexafluorophosphate

Organic solvents
Ethylene Carbonate

Why?
High ionic Conductivity
Electrochemical Stability
Compatibility with Electrode Materials
Low flammability

Question 9

What is the role of the remaining component separator?

Answer 9

Electrical Insulation
Ionic Conductivity
Mechanical Stability
Thermal Stability
Chemical Compatibility
Contributing to Battery safety

Question 10

What are the main degradation mechanisms on the anode side?

Answer 10

Solid Electrolyte Interphase (SEI) Formation and Growth
Mechanical Stress and Volume Changes
Lithium plating
Electrolyte Decomposition
High temperature Effects
Electrical stress

Question 11

What are the main degradation mechanisms on the cathode side?

Answer 11

Structural and Phase Changes
Transition Metal Dissolution
Surface Film Formation
Electrolyte Oxidation
Mechanical Stress
Microstrutural Degradation

Question 12

How do the degradation mechanisms depend on the choice of active materials?

Answer 12

Energy Density vs. Stability: Higher energy density materials often operate at higher voltages, which can stress the electrolyte and active materials, accelerating degradation.

Termal stability: Materials with higher termal stability are less prone to degradation mechanisms triggered by elevated temperatures, such as electrolyte decomposition and active material dissolution.

Mechanical Stability: Active materials that undergo minimal volume changes during cycling exhibit lionger lifespans due to reduces mechanical stress and particle fracturing.

Question 13

How do the operation conditions influence the degradation of LiBs?

Answer 13

Temperature
High - Faster SEI layer growth
Low - Lithium plating on the anode
State of charge
High - Cathode crystal structure can change
Deep discharge - Irreversible capacity loss.
Charging Rate
Fast - Uneven lithium ion distribution
Slow - Less efficient an contribute to SEI growth
Discharging rate
High - Increase temperature and mechanical stress in electrodes
External Mechanical stress - Vibration - Increase risk of internal short circuits
Cycling Frequency
Environmental conditions

Question 14

What are the preparation steps of a lithium ion battery? (Cylindrical cell)

Answer 14

Materials
Mixing
Coating
Drying
Calandering
Slitting
Tab welding
Winding
Canning
Electrolyte filling
Formation

Question 15

What is the anode and Cathode material?

Answer 15

Anode - Copper
Cathode - Aluminium

Question 16

What is BMS?

Answer 16

Battery management system.
System that protects against over voltage, over current and discharging the battery too much.
Keeps track of what goes in and what goes out and reversed

Question 17

What is electrochemical potential?

Answer 17

It’s the tendency to lose electrones

Question 18

How do you calculate battery capacity?

Answer 18

C = I * t

I is the current (A), t is the time (h)

Calculates how much charge a battery can store and deliver over time

Question 19

How do you calculate the energy Capacity?

Answer 19

E = V *C

V is the nominal voltage and C is the capacity.

Calculates the total energy a battery can store.

Question 20

How do you calculate C-rate?

Answer 20

C-rate = I/C

I is the current, and C is the capacity.

Calculate the charge and discharge rates of a battery relative to its capacity.

Question 21

How do you calculate the Efficiency of a battery?

Answer 21

Efficiency = Energy Output / Energy Input *100%

Calculates the efficiency of a battery.

Question 22

What is the benefits and limitations with cylindrical cells?

Answer 22

Benefits:
Robust design
Good thermal management, but central parts of the cell might be more prone to heat buildup
Manufacturing and consistency

Limitations:
Space Efficiency- Potential inefficiencies in packaging.
Weight - Slightly heavier due to more robust casing.

Question 23

What is the benefits and limitations with Prismatic cells?

Answer 23

Benefits:
Space Utilization - Can be packed closely together.
Scalability - Available in various sizes

Limitations:
Cost - More complex manufacturing processes, leading to higher costs
Thermal Management - Challenges due to their larger flat surfaces

Question 24

What is the benefits and limitations with pouch cells?

Answer 24

Benefits:
Lightweight and flexible design - Soft and flexible packaging
High Energy Density - The absence of heavy casing allows for a higher ratio of active material, enhancing energy density.

Limitations:
Swelling - Can swell due to gas buildup over time.
Durability - Less durable and more susceptible to punctures and swelling.

Question 25

What is thermal conductivity?

Answer 25

Measures the ability of a material to conduct or transfer heat.

Question 26

What are the key areas of focus for next generation batteries?

Answer 26

Higher energy density, faster charging times, longer lifespan, improved safety, and reduced environmental impact.

Question 27

What is energy density?

Answer 27

Energy density is the amount of energy that can be stored or contained within a given unit of volume or mass.

Question 28

What does “LEO the lion says GER” means?

Answer 28

LEO - Loss of Electrons is Oxidation (Occurs in the anode)
GER - Gain of Electrons is Reduction (Occurs in the cathode)