Project 1 Mechanical design of battery pack

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 (Cell: ANR26650M1-B), these 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 systems to meet end-of-life power and energy requirements with minimal pack oversizing.

Its application in various sectors

COMMERCIAL USAGE Advanced lead acid replacement batteries for: Data center UPS Telecom backup IT backup Autonomously guided vehicles (AGVs) Industrial robotics and material handling equipment

GOVERNMENT USAGES Military vehicles Military power grids Soldier power Directed energy

GRID USAGES Frequency regulation Renewables integration Reserve capacity Transmission and distribution

TRANSPORTATION USAGES Hybrid, plug-in hybrid and electric vehicle battery systems for: Commercial vehicles Off-highway vehicles Passenger vehicles

Reference of technical data from data sheet is given below:

Battery — Combination of Two or more no. of cells is called as battery. These cells are connected either in series or in
parallel combination.

Module - The combination of no. of batteries together forms a module. These batteries are connected together via a
connector which is solder strips. In the module a Battery management system (BMS) installed which protects the
cells from damage due to overcharging, Temperature.

To prepare Battery pack capacity: 18 kWh

Calculations as per assumptions of 18 kWh battery pack, basically 18kWh is energy required to achieve the vehicle its
power range. It is depending upon the voltage (V) parameter and ampere-hour (Ah) capacity.

The cell capacity (Ah) of single cell = 2.5 Ah

The cell Voltage (V) of single cell = 3.3 The cell capacity (Ah) of single cell = 2.5 Ah
Therefore, the value of energy of single cell is calculated using,

Single cell Energy (Wh) = Cell Capacity (Ah) x Cell Voltage (V)

Single cell Energy (Wh) = 2.5x 3.3

Single cell Energy (Wh) = 8.25 Wh.

From this we can calculate no. of cells required to manage 18 kWh Energy
Therefore, the no. of cell are = 18 kWh / 8.25 Wh

No. of cells are 2182.

We need minimum 2182 no. of cells to get 18 kWh energy, Now based on that we need to decide configuration i.e;
series & parallel.

In series configuration the capacity of battery remains the same and voltage increases due to summation of all
individual cell in series.

In parallel configuration the voltage of battery remains the same and capacity of the battery increases.
Voltage Rating of Battery: -

For Series configuration let us assume that 138 V at one leg,

So, No. of cells in series are 138/3.3 = 41.81 = 42

Battery Capacity: -

For parallel configuration we assume that capacity should be 130 Ah
Therefore, No. of Parallel legs are 130/2.5 = 52

Battery Pack Energy: -

Current Capacity x Voltage

130 x 138.6

18018 Wh = 18.018 kWh

Therefore, our battery module configuration would be 42S52P
Current supplied by the Battery: -

We have already calculated battery capacity which is 130 Ah means it is going to supply 130 A current per hour, which
be consider as C rate.

Internal Resistance of Battery: -

The entire resistance encountered by a current as if it flows through a battery from the negative terminal to positive
terminal is known as internal resistance of battery.

Objective 3: - Design a detailed battery pack drawing along with its enclosure.
To design battery enclosure, we have to consider Mechanical Parameters.
Mechanical Parameters: -

* Battery Dimensions:

Diameter = 26mm
Length or Width = 65mm
Mass = 76g

ANR26650 cell has 26 mm Diameter and 65 mm height. By knowing this parameter, we can calculate the size of the
casing required which is used for battery pack.

Length of Casing (L) = No. of cells in Parallel * cell diameter + space between two adjacent cells + outer hard casing
L=52* 26mm + 52mm + 10mm

L=14144mm

Width of Casing (W) = No. of cells Series * cell diameter + space between two adjacent cells + outer hard casing
W = 42 * 26mm + 42mm + 10mm

W=1144mm

Height of Casing (H) = Height of the single cell only i.e, 65mm + hard casing

Height = 65mm + 10mm

Height = 75mm

Weight of battery pack = No. of cells * weight of single cell + casing weight

Weight = 2182 * 76g + 1000g

Weight = 165847 g = 166.84 kg

Conclusion:modelling of 18KWh battery pack and its parameters are listed in the table below.

Parameters Cell Voltage Cell Capacity (Nominal/Minimum) (0.5C rate) Internal Resistance Voltage Current Capacity Power or Energy Series Cell Parallel Cell Total Cell Length Width Height Weight Value

Values 33V 2.5/2.4 AW 6 moh 138.6 V 130A 18.018 kWh 42 52 2182 1414 mm 144mm 75mm 166.84 kg