Project 1 Mechanical design of battery pack
ANR26650M1-B Specifications
Nominal Ratings
Voltage: 3.3 Volts
Capacity: 2.5 Ah
Energy: 8.25 Wh
Specific Power: 2600 W/kg
Impedance (1KHz AC Typical) 6 mΩ
Cycle Life at 1C/1C, 100% DOD: > 4000 cycles
Cell Type: 26650 Lithium Ion Power Cylindrical Cell
Discharging
Max Continuous Discharage: 50 A
Max Pulse Discharge Current >50% SOC (10s): 120 A
Minimum Voltage: 2 Volts
Temperature: -30ºC to 55ºC
Charging
Recommended Standard Charge: 2.5 Amps
Max Charge Rate: 10 Amps
Max Pulse Charge Current <50% SOC (10s): 25 A
Float Voltage: 3.45 Volts
Recommended charge V & Cut-off Current: 3.6 Volts, taper to 125mA
Temperature
(reduce charging current to 250mA when under 0ºC): 0ºC to 55ºC
Mechanical
Diameter: Ø25.96 +/- 0.5 mm (1.0")
Length: 65.15 +/- 0.5 mm (2.6")
Mass: 76 g
Cylindrical Cell Primary Applications:
- Portable high power devices
- Stationary battery backup systems
- Grid stabilization energy storage systems
- Commercial truck and bus hybrid electric vehicles (HEVs)
Lithium Ion Cell Benefits:
- Power: Over 2,600 W/kg and 5,800 W/L
- Safety: Excellent abuse tolerance and environmentally friendly
- Life: Excellent calendar life, 10X cycle life vs. conventional lithium ion
As stated battery pack capacity required =18kwh
single cell capacity = cell volt x cell current =2.5 x3.3 = 8.25Wh
Assumption car range = 500km and volt req =500v
energy req per km= 18000/500 = 36kw/km
no. of cell in series(ncs) = volt req by car/ nominal voltage of cell 500/3.3 =152 cells in series required
no. of cell in parallel req total P=NO. OF cell in pARALLEL X NOMINAL VOLT X NO. OF cell in SERIES X NOMINAL CAPACITY
459036 = 18000/152X2.5X3.3 =14 CELLS
Battery pack total enErgy = ncp x ncs x volt of single cell x capacity of cell = 14 x152 x3.3 x2.5 = 18kwh
Battery pack capacity = ncp x capacity of cell = 14 x 2.5= 35 amphr
Total number of cells for battery pack = 152 x14 =2128 cell
Total volume of battery pack=2128*0.0345=73.3125 m^3.
Elements of a battery pack-
cell - A cell basically consist of Anode,Cathode,Seperator,positive cap,negative cap and shell.
Cell assembly - a battery can be assembles in various arrangment eg 7S3P OR 5S5P it is done ACQ to need of vehicle.
Cell Holder - The mainn function of a battery holder to keep cells fixed in place safely and securely also it is used to keep cells in a proper arrangement so that there will be a decrease innmechanical vibrations.
Electric connection- as cells are now hold by a holder a electrical connection is made between them there are many ways to connect two cell some are
1)Copper and Nickel Buses
2)MAGNETS
3)Spot-welding a Copper / Nickel sandwich
BMS - Battery management system (BMS) is technology dedicated to the oversight of a battery pack, which is an assembly of battery cells, electrically organized in a row x column matrix configuration to enable delivery of targeted range of voltage and current for a duration of time against expected load scenarios.
BTMS- Battery Thermal Management System is a complete thermal system solution that maintains the critical operating temperature ranges of vehicle batteries