Cell & Pack Design Flashcards
What happens by connecting cells in parallel?
Increase voltage
What happens by connecting cells in series?
Increase capacity
What are the 3 main metrics for the design of a battery pack?
Discharge time, pack voltage and energy
How many cells in series are required to achieve a pack voltage of 360 V using LIB cells @ 3.6 V?
100 cells
How many cells are required in the pack to achieve a pack with 24 kWh total energy with a cell capacity of 3.35 Ah and using LIB cells @ 3.6 V?
1990 cells
E cell = 12.06 Wh
No. cells = (24 x 1000)/12.06
How many cells are required in the pack to achieve a pack with 24 kWh total energy using LIB cells @ 3.6 V? arranged in parallel?
20 cells
cells in parallel = Total no. cells / cells in series
What does a pack description of 100S-2P tell us?
The module is arranged with 100 cells in series and 20 cells in parallel
What are the 5 benefits of the cell casing?
1) Protect cells from ingress of oxygen
2) Protect cells from moisture
3) Protect cells from other environmental compounds
4) Mechanical protection
5) Keeps cell components in contact
Name 3 types of cell casings
1) Coin
2) Cylindrical
3) Prismatic
4) Pouch
What are the 7 components in a cell module?
1) Casing
2) Clamping frame
3) Temperature sensors
4) Cell
5) Terminals
6) Current collectors
7) Cooling
What are the 8 components in a pack?
1) Upper case
2) Battery modules
3) ‘Bus bars’
4) Contactors
5) Fuses
6) Disconnect
7) Cooling system
8) Battery management system (BMS)
What are the 2 methods of battery charging?
Galvanostatic (constant current) and potentiostatic (constant voltage)
What does the BMS measure?
State of charge, state of health, safety & critical functions and load balancing
What are the dimensions of a 18650 cylindrical cell?
18mm diameter and 65mm height.
What is the volume of a cylinder?
pi r^2 H
