Introduction to battery-management systems- COURSERA WEEK 02 QUIZ -1.2.5 ANSWERS

 

Practice quiz for lesson 1.2.5

Total points 3

1.

Question 1

What are some key properties that must be satisfied by an electrolyte for a lithium-ion cell? (Select all that apply.)

1 / 1 point

It must conduct ions with little resistance but be an electronic insulator.

Correct

Yes. It is designed to be an ionic conductor, but it must also be an electronic insulator to prevent short circuit.

It must be aqueous.

It must be able to withstand voltages in excess of 3V without breaking down.

Correct

Yes. Most lithium-ion cells have voltage greater than 3V, and so it is important that this voltage does not damage the electrolyte.

It must comprise a solvent plus a lithium-based salt.

Correct

Yes. The salt provides lithium ions for conducting current internal to the cell, and the solvent provides a medium into which the salt dissolves.

2.

Question 2

Desirable properties for separators in lithium-ion cells include: (select all that apply)

1 / 1 point

The separator must have pores through which ions in the electrolyte can move to traverse from one side to the other.

Correct

Yes. The ions must be able to move from one electrode region to the other for the battery cell to supply current to the load.

The separator must be as thick as budget constraints allow.

The separator must be an electronic insulator.

Correct

Yes. If the separator were electronically conductive, the cell would short circuit and discharge all of its energy internally. The separator must instead prevent electronic current from flowing internal to the cell, so must be an insulator.

The separator must have holes large enough for negative-electrode particles to contact positive-electrode particles to complete an electrical circuit.

3.

Question 3

The negative-electrode current collector is usually made from a metal foil of which element?

1 / 1 point

Copper

Correct

Yes. Copper is chosen because it does not degrade under the potentials normally experienced by the negative electrode.