Project 1 Mechanical design of battery pack

Cell: ANR26650M1-B

A123’s high-performance Nanophosphate lithium iron phosphate (LiFePO4) battery technology delivers high power and energy density combined with excellent safety performance and extensive life cycling in a lighter weight, more compact package. Our cells have low capacity loss and impedance growth over time as well as high usable energy over a wide state of charge (SOC) range, allowing our systems to meet end-of-life power and energy requirements with minimal pack oversizing.

Applications Used :-

Advanced lead acid replacement batteries for

• Datacenter UPS
• telecombackup
• IT backup
• Autonomous guided vehicle
• industrial robotics and material guided equipment
• medical devices

GOVERNMENT SOLUTIONS

• Military vehicles
• Military power grids
• soldier power
• directed energy
  
  

GRID SOLUTIONS

• Frequency regulation
• renewables integration
• reserve capacity
• transmission and distribution

TRANSPORTATION SOLUTIONS

Hybrid, plug-in hybrid and electric vehicle battery systems for:

• Commercial vehicles
• Off-highway vehicles
• Passenger vehicles

Technical Data :-

Cell Dimensions	26 x 65 mm
Cell Weight	76g
Cell Capacity (nominal/minimum) (0.5C Rate)	2.5/2.4 Ah
Voltage (nominal)	3.3V
Internal Impedance (1kHz AC typical)	6mΩ
Power	2600 W/kg
Recommended Standard Charge Method	2.5A to 3.6V CCCV, 60 min
Recommended Fast Charge Method to 80% SOC	10A to 3.6V CC, 12 min
Maximum Continuous Discharge	50A
Maximum Pulse Discharge (10 seconds)	120A
Cycle Life at 20A Discharge, 100% DOD	>1,000 cycles
Operating Temperature	-30°C to 55°C
Storage Temperature	-40°C to 60°C

About Cell and Module :-

The LithiumWerks ANR26650M1-B is the next generation of A123 Systems’ pioneering 26650 cylindrical cell, now with greater power and energy density and lower impedance. This versatile lithium ion cell is suitable for a wide variety of applications and system designs. Proven performance in the toughest conditions, combining durability, reliability, and safety, the ANR26650 cell offers an excellent combination of price-performance.

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

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

Discharging

Max Continuous Discharage: 50 A
Max Pulse Discharge Current >50% SOC (10s): 120 A
Minimum Voltage: 2 Volts
Temperature: -30ºC to 55ºC

Battery Calculation :-

Battery Energy = 18kwh

Voltage = 400v

No of cells = energy / (nominal voltage*capacity)

N = 18000 / (3.3*2.5)

N = 2182

We need minimum 2128 cells to get 18kwh energy, based on this we need to decide the cells will be series are in parallel, in series capacity remains same voltage will be the sum of individual cell voltage , parallel configuration voltage remains same

we know that 400v need to run the vehicle, and the nominal voltage of one cell is 3.3v

so No of cells = voltage / nominal voltage

N = 400/3.3

Ns = 121.21 = 122 series cells required for generate 400v capacity

Now we find out for parallel connection ,cells in parallel = total cell/Ns

Np = 2182 / 122

Np = 17.8 = 18

hence we take 18 cells for each parallel row, then the cell architecture is 122S18P

Battery Capacity :-

Capacity = parallel cell row*individual cell capacity

Cp = 18*2.5

Cp = 45Ah

Current supplied by the battery :-

Calculated battery capacity is 45Ah which means 45A current per hour to charge the battery

Range :-

R = capacity / energy consumed per kilometer

R = 18000 / 100

R = 180 km

so our vehicle will able to cover 180 km

Battery Dimensions :-

Length of casing (L) = Number of cells at series*(cell diameter(26) + margin at both side of the cell(4) + clearence at the side (diameter of edged cell + margin)

L = 122*30+60

L = 3720mm

Breadth of casing (L) = Number of cells at parallel*(cell diameter(26) + margin at both side of the cell(4) + clearence at the side (diameter of edged cell + margin)

B = 18*30+60

B = 600mm

Height of casing (H) = 65 +35 (Height of cell + margin for wiring, cell holder and metal strips)

H = 100mm

weight of battery pack :-

cell weight = 76g

Number of cells = 2182

Battery pack weight (w) = Cell weight *number of cells + weight of accessories

W = 76*2182 + 4.5 = 165.8+4.5 = 170.3kg

Battery Pack assembly equipment:-

Conclusion :-

Lithium ion batteries are great powerd source for many application but they require preventive protection during charging and discharging