Mechanical design of battery pack

AIM-

Battery pack capacity: 18 kWh

Cell: ANR26650M1-B

Prepare a detailed battery pack drawing along with its enclosure

THEORY-

Lithium Werks’ 26650 cells are capable of delivering very high power due to its use of patented Nanophosphate ® battery technology. Based on lithium iron phosphate chemistry (LiFePO4 ), the cells are inherently safe over a wide range of temperatures and conditions. Whether the application requires outstanding cycle life or stable float reliability, the Lithium Werks’ 26650 cells are suitable for a wide variety of power, pulse, or stand-by applications. Nanophosphate® Technology 26650 Lithium Ion Power Cell Nanophosphate® battery technology offers stable chemistry, faster charging, consistent output, excellent cycle life and superior cost performance. It provides the foundation for safe systems while meeting the most demanding customer requirements. Multiple layers of protection are employed at the chemistry, cell and system level to achieve an energy storage solution with superior safety and abuse tolerance compared to metal oxide lithium-ion chemistries.

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

Certifications
Transportation: UN 3480 (UN38.3), CIQ
Safety: UL 1642, IEC 62133

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.

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

Mechanical
Diameter: Ø25.96 +/- 0.5 mm (1.0")
Length: 65.15 +/- 0.5 mm (2.6")
Mass: 76 g

Applications-

• Energy storage
• Uninterruptible Power Supplies
• Communication technologies
• Aerospace
• Electrified mobility devices
• Industrial equipment
• Medical devices
• Toys

Cell data-

Calculation-

1. Cell energy=Nominal voltage*Nominal cell capacity

=3.3*2.5=8.25Wh

2. Cell volume=Pie*r*r*h

=3.14*0.013*0.013*0.065

=0.0344m^3

3. Cell energy density=Cell energy/cell volume

=8.25/0.0344

=239.17Wh/m^3

Now Assuming we have 46 cells in series and 48 cells in parallel connection

4. Total No of cells=No of cells in series*No of cells in parallel

=46*48

=2208cells

5. Voltage of the pack=Nominal voltage*cells connected in series

=3.3*46

=151.8V

6. Current capacity of the battery pack=Cell capacity*Cells connected in parallel

=48*2.5

=120Ah

7. Total energy of the battery pack=Voltage*current capacity

=148.5*120

=18.216kWh

8. Total volume=Cell volume*Total No of cells

=0.0344*2208

=76.022m^3

9. Total weight of the battery pack=Total No of cells*Weight of each cell

=2208*0.076

=167.808kg

Conclusion-

So in this project we have prepared approx 18kwh capacity of battery pack after the assumption and calculated its parameters.