Week 5 Challenge

QUESTION 1 :-

Consider a scenario where an aggressive driver is accelerating very rapidly and braking harshly in a city driving. Is battery better a choice to supply power than UC in this scenario?

1. True
2. False

Why?

Solution: Battery is not a better choice in the given driving scenario.

Condition: The driver is driving aggressively. Very rapid accelerating and braking (deceleration) take place in the driving.

Battery:

• A battery converts chemical energy to electrical energy and it is reversible in chemical reactions.
• They have low power density
• The battery charge/ Discharge process is relatively slower.

Ultra-Capacitor:

• Ultracapacitors are also known as supercapacitors.
• The source of energy is electrical energy.
• They are a very high energy density.
• As the Ultracapacitors are bigger capacitors, they store a large amount of electrical charge than the chemical batteries.
• They are having high power density.
• Ultracapacitors undergo a quick charge and discharge rate.

Result:

As per the above comparison between battery and ultracapacitor, it is understood that Ultracapacitors are more suitable for vehicles that accelerate and decelerate very frequently.

Question 2:

Consider the following components.

1) Lead-acid battery 2) Nickel-cadmium battery 3) Nickel Metal hydride battery 4) Lithium-ion (specify chemistry) battery 5) Ultra Capacitor

Note: In the case of a range of energy density, take the average value for the plot.

Create a plot with energy density on the X-Axis and cell voltage on the Y-axis.

Comment on the capabilities of these batteries based on the plot created.

Answer:

Energy Density: It is the measure of how much energy a battery contains in proportion to its weight. This measurement is typically presented in watt-hours/kilogram. The higher the energy density, the longer the runtime.

Lead Acid batteries:

Lead-acid batteries have relatively low energy density.

Nickel-Cadmium Battery:

Nickel Cadmium has a much higher energy density compared to lead-acid batteries.

Nickel-Metal Hydride Battery:

Ni-MH batteries can have two to three times the capacity of NiCd batteries of the same size, with high significance and also much less than lithium-ion batteries.

Lithium-ion battery:

Lithium-ion batteries have a high energy density.

Ultracapacitor:

Energy density is more in ultracapacitors compared to capacitors.

The values of energy densities of different batteries and cell voltage are shown in the below table and also the same is represented in the X-Y plot shown below.

Battery name	Energy density	Cell voltage
Lead-acid battery	35-40	2.1
Nickel Cadmium	40-60	1.2
Nickel Metal Hydride	60-120	1.2
Lithium-ion	100-265	3.6/ 3.7/ 3.8/ 3.85
Ultracapacitor	89.6	3.5

Question 3:

For the above-mentioned components on the same plot (retain the previous plot) created in the previous

Create a plot with power density on the X-axis and cell voltage on the Y-axis.

Answer:

The power density of the above set of batteries is as shown below.

Battery name	Power density (W/Kg)	Cell voltage (V)
Lead-acid battery	180	2.1
Nickel Cadmium	150	1.2
Nickel Metal Hydride	1000	1.2
Lithium-ion	340	3.6
Ultracapacitor	496	3.5

The power density plot of the batteries is shown below in the plot.

Question 4:

Consider the following scenario:

A battery has just been manufactured in the industry and has been connected to a charger for the first time. The electrode marked as (1) in the picture below is the negative electrode.

1. True
2. False

Answer:

True. The number indicated as 1 is a -ve electrode.

Lithium-ion batteries generate DC power by utilizing chemical reactions.

• During discharge, lithium ions from the -ve anode move through the electrolyte to gets intercalate the +ve cathode.
• During charging, electrons move from anode to cathode in the external circuit.
• Electrons flow to balance the cell voltage.
• During the electrochemical process, the anode is -ve and the cathode is +ve.
• At the first time charging, the lithium-ion from the cathode gets attached to anode and it forms the inseparable layer on the anode.
• A solid Electrolyte Interface (SEI) is formed at the anode. Anode gets decomposed if it comes in contact with the electrolyte. SEI protects the anode.

Summary:

A battery has just been manufactured in the industry and has been connected to a charger for the first time. The electrode marked as (1) in the picture below is the negative electrode. this is true