University:
Conestoga College
Course:
ERGY8070 | Energy, Storage and Management
Academic year:

2021
Views:

459

Pages:

2
Author:

S T Cherukuri

Week 4 ERGY8070 Battery Storage Practice Problems #1 1. True or False: connecting batteries in parallel increases their voltage. 2. What is the internal resistance of a cell where the voltage difference across said cell when no current flow through the circuit is 4V. When a current of 1A is flowing, the terminal voltage difference falls to 3.9 Volts? 3. True or False: Nickel Cadmium batteries are currently in favour due to their use of cadmium? 4. What are some reasons why lead acid batteries are commonly used? 5. The voltage difference across a cell when no current flow through the circuit is 3.6V. When a current of 0.3A is flowing, the terminal voltage difference falls to 3.55 Volts. What is the power delivered by the battery to the load? 6. What is the round-trip efficiency of a cell with an average discharge voltage of 1.2, an average charge voltage of 1.3 and a C/D ratio of 1.25? Week 4 ERGY8070 ANSWERS 1. False (see Week 4 Slide 27) 2. 𝑅! = 3. "! #"" $# = %#&.(" )* = 0.1𝛺 = 100𝑚𝛺 False. Cadmium is a toxic heavy metal. Therefore, nickel cadmium batteries are no longer commonly used. 4. They are well understood, mature batteries with a low self-discharge rate. They are relatively low cost. They can also have high discharge efficiencies. 5. 𝑃 = 𝑉+ ∗ 𝐼+ = 3.55 ∗ 0.3 = 1.065𝑊 6. 𝜂,- = *./,01/ 345670,1/ "89-01/ $ *./,01/: ;70,1/ "89-01/ < =0-48 % = ).> ).&∗).>@ = 0.738 = 74.8%