Week 5 Challenge

Q1) 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?

True

False

Why?

In the case of aggressive driving in the city, it is FALSE that a battery is a better choice to supply power than UC(Ultracapacitors).

In the case of aggressive driving by rapid acceleration and harsh breaking, ultracapacitors play a major role to provide sudden high power requirements from the battery and sudden high current charging during braking.

We can discuss how it is doing its actions in electric vehicles.

Batteries and ultracapacitors do a similar job as storing electricity but in completely different ways.

Ultracapacitors deliver quick bursts of energy during peak power demands, then quickly store energy and capture excess power that is otherwise lost. They efficiently complement a primary energy source in today's applications because they discharge and recharge quickly.

Batteries can hold large amounts of power, but they take hours to charge up. Capacitors, on the other hand, charge almost instantly but store only tiny amounts of power.

In our electric-powered future, when we need to store and release large amounts of electricity very quickly, supercapacitors (also known as ultracapacitors) come into action

These is the conditions where ultracapacitors have high power density and low energy density.

While sudden acceleration from the standby mode of EV,high torque is required which inturns require high power demand instantly. Which is provided by ultracapacdischarge it disharge powewithinsa tantly within a short duration of time.

Whilebrakingharsh breaking conditions a high current is rea generated for a short duration of time. which can be absorbed by the ultracapacitor as it charges instantaneously.

Battery can't able to store this sudden regenerative power during braking.

Working of battery:

Batteries have two electrical terminals (electrodes) separated by a chemical substance called an electrolyte. When you switch on the power, chemical reactions happen involving both the electrodes and the electrolyte. These reactions convert the chemicals inside the battery into other substances, releasing electrical energy as they go.

Once the chemicals have all been depleted, the reactions stop and the battery is flat.

Working of Ultracapacitors:

Ultracapacitors also have two metal plates, but they are coated with a sponge-like, porous material known as activated carbon. And they are immersed in electrolytes made of positive and negative ions dissolved in a solvent.

One carbon-coated plate/electrode is positive and another one is negative.

During charging, ions from the electrolyte accumulate on the surface of each carbon-coated plate.

Q2) 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.

Comparing the average cell voltage values and its energy density for different battery types.

Here we are going to compare the cell voltage and energy density for the battery types,

Lead acid battery-Cell voltage:2V, Energy density:30-50Wh/Kg.

Nickel Cadmium battery-Cell voltage:1.2V, Energy density:45-80Wh/Kg.

Nickel Metal Hydride battery-Cell voltage:1.2V, Energy density:60-120Wh/Kg.

Li-ion (LMO -Lithium manganese oxide) battery-Cell voltage:3.8V, Energy density:100-135Wh/Kg.

Ultra capacitors- Average Voltage:3V, Energy density 1-10Wh/Kg

Now we have to create a plot for these battery types and compare them.

Cell Type	Cell Voltage(V)	Average Energy density(Wh/Kg)
Lead acid	2	40
Ni-Cd	1.2	62.5
Ni-MH	1.2	90
Li-ion(LMO)	3.8	117.5
Ultracapacitor	3	10

Here in the plot, the values above the blue dots represent the energy density and cell voltages of corresponding cell types shown in the table.

From the plot, we understand that,

Li-ion battery type has a higher voltage level and higher energy density.

Nickel-cadmium and Nickel metal hydride have nearly equal cell voltages but their energy density is different. Nickel metal hydride has a higher energy density than the Ni-Cd battery type.

Lead acid battery type has a medium voltage higher than Ni-cd and Ni-MH and its energy density is lesser than other types of batteries except for ultracapacitors.

Ultracapacitors have a high voltage range but their energy density is lesser than all types of batteries.

Thus ultracapacitors are used only in conditions where high power requirements are at a small amount of duration.

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.

The voltage and power density values are mentioned below,

Lead acid battery-Cell voltage:2V, Power density: Less than 300 W/Kg.

Nickel Cadmium battery-Cell voltage:1.2V, Power density:150-300W/Kg.

Nickel Metal Hydride battery-Cell voltage:1.2V, Power density:Less than 200W/Kg.

Li-ion (LMO -Lithium manganese oxide) battery-Cell voltage:3.8V, Power density:100-1000W/Kg.

Ultra capacitors- Average Voltage:3V, Power density 600W/Kg.

For the above values we need to plot a chart,

Cell Type	Average Power density (W/Kg)	Cell Voltage(V)
Lead acid	155	2
Ni-Cd	225	1.2
Ni-MH	105	1.2
Li-ion(LMO)	550	3.8
Ultracapacitor	600	3

From the above plot, we can see that,

Ultracapacitors are having high power density and their voltage level is also above medium level voltage as 3V.

The power density of Lead acid battery types is in between Ni-metal hydride and Ni-cadmium battery types.

Among all Ni-metal hydrate battery types are having lesser power density on average.

Conclusion:

By comparing plots from questions 2 and 3 we can come to know that,

Li-ion battery types are almost in the higher preference range for better energy density, power density, and voltage ranges.

However, Ultracapacitors are also suitable for conditions where high power requirements in shorter duration.

Other types excluding the above are also used for applications corresponding to their specification matching of loads.

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.

True

False

From the given figure it is clearly understood that the electrode marked as (1) is not a negative electrode (Anode), as when loading is connected externally the Li-ions move from the anode to cathode(1) as shown above. Here the above-shown figure is discharging and not charging.

Thus the statement mentioned in the question is FALSE.

Battery mentioned:

Here Li-ion is passing from anode to cathode(1) through a separator.

Thus this battery type is a Li-ion battery.

Reason:

Here the question is given as the battery is charging for the first time after manufacturing

So, at the initial condition, the anode doesn't consist of even a single Li-ion. All ions are in the cathode side based on Li-ion chemistries.

For first charging the Li-ions move from the cathode(1) to the anode(saffron as in the image).

The electrons move from cathode(1) to the anode via external load.

Conclusion:

Thus above question(First charging) and the given figure(Discharging), both are different cases. Thus the statement is FALSE.