Project 1 

AIM: Prepare a detailed battery pack of Cell: ANR26650M1-B, drawing along with its enclosure, and Battery pack capacity is 18kWh. State your assumptions.

OBJECTIVE: 

1) Collecting the data of Cell: ANR26650M1-B from Nanophosphate High Power LithiumIon Cell PDF.

2) Calculating all Electrical parameters for 18 kWh Battery Pack.

3) Calculating all Physical dimensions for Battery Pack.

4) Consider perfect enclosure for dimensions that we calculated for the Battery Pack.

Battery pack capacity: 18 kWh

Cell: ANR26650M1-B 

Prepare a detailed battery pack drawing along with its enclosure. State your assumptions.

Prepare a detailed battery pack drawing along with its enclosure. State your assumptions.

Introduction

As we know that the electric vehicle market is gradually increasing. With the growth of an electric vehicle, the growth and interest in Lithium-ion cell are also increasing. The energy source for an electric vehicle is stored in cylindrical cells.

Lithium-ion cells are capable of delivering very high power. Lithium-ion cells are used in aerospace, automotive electric vehicle, mobile devices, medical devices and other electronic devices which is based on these cells. The battery pack is installed in lower-floor of the electric vehicle so that weight may distribute equally and also the centre of gravity also maintain properly.

The high voltage battery pack is one of the most important components of any electric vehicle. The traction battery of an electric vehicle must achieve the following thing:

• Provide maximum traction motor torque

Vehicle range in sense of kilometre.

• To achieve the proper life cycle of battery

The battery pack of an electric vehicle is generally having a series or parallel combination. Large battery pack have multiple cell modules, in which many numbers of cells are kept together to build a large battery pack. Basically, a series connection is used to compound the voltage whereas the parallel connection is for compound current capacity. A battery cell consists of five major components that are electrodes - anode and cathode, separators, terminals, electrolyte and enclosure.

Mechanical Design of battery pack:

The high voltage battery it is one of the most important component of a battery electric vehicle (BEV). The battery parameters have a significant influence on other components and attributes of the vehicle, like:

• maximum traction motor torque

• maximum regeneration brake torque

• vehicle range

• vehicle total weight

• vehicle price

Pretty much all major aspects of a pure electric vehicle (EV) depend on the parameters of the high voltage battery. For our electric vehicle battery design we are going to start from 4 core input parameters:

• chemistry

• voltage

• average energy consumption of the vehicle on a driving cycle

vehicle range

A battery consists of one or more electrochemical cells (battery cells) which are converting chemical energy into electrical energy (during discharging) and electrical energy into chemical energy (during charging). The type of elements contained within a battery and the chemical reactions during discharging-charging events define the chemistry of a battery.

A battery cell consists of five major components: electrodes - anode and cathode, separators, terminals, electrolyte and a case or enclosure. For automotive applications there are different types of cells used:

mathematical calculation designing an 18kWh the vehicle proper range. is depending upon the voltage (V) parameter and ampere-hour or capacity (Ah).

used design high battery vehicle up For calculation, assumed 145.2 nominal voltage for series connection.

General required depending upon single cell:

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

Calculation as per assumptions:- 18kWh Battery Pack

 calculation for designing an 18kWh battery pack, basically 18kWh is energy require to achieve the vehicle its proper range.  It is depending upon the voltage (V) parameter and ampere-hour or capacity (Ah).

Here we  design a high voltage battery pack for an electric vehicle to achieve its range up to 220 km. For this calculation, I assumed 145.2 V a nominal voltage for series connection.

Basically, the value of the volume of the cell is used to find out the total volume of the battery pack.
- Single Cell Energy (Wh)

= Cell Capacity (Ah) x Cell Voltage (V)

= 2.6 x 3.3

= 8.58 Wh

The value of a single cell is used to calculate the total energy of the battery pack.
-Single Cell Energy Density

Volumetric energy (Wh/m^3) = Single Cell Energy / Volume of each cell

                                         = 8.58 Wh / 0.03451 m^3

                                         = 248.62 Wh/m^3
Gravimetric energy (Wh/kg) = Single Cell Energy / Single Cell Mass

                                          = 8.58 Wh / 0.076 kg

                                          = 112.89 Wh/kg

 Calculation of High Voltage Battery Pack
For design and calculation of battery pack here, I assume a vehicle to achieve 250 km in 18 kWh battery pack. Also, I assume 145.2 nominal voltage for series connection.
So,
Vehicle Range = 250 KM (assumed)
Battery Pack capacity = 18.121 kWh or 18120.96 Wh (For better and accurate calculation here I change kWh)
Now,
We will calculate per km average energy = 18120.96 / 250
                                                           = 72.483 Wh/km

Therefor,
Battery Pack total energy = Average energy x km
                                     = 72.483 x 250
                                     = 18120.96 Wh or 18.120 kwh

Let’s assume Nominal voltage for series connection = 145.2 V, Basically, this depends upon the motor power, We can decide the value according to the motor.
- Number of cells connected in series
= Nominal voltage of series connection / Nominal voltage of a single cell
=145.2 V / 3.3 V
= 44

44 Cells will be connected in a series connection to provide a proper voltage.

- Energy for battery pack (wh)

= No. of cells connected in series x Single-cell energy

= 44 x 8.58 wh

= 377.52 wh

-- Number of cells connected in parallel

= Battery pack total energy (wh) / Energy for battery pack (wh)

=18120.96/377.52

= 48

48 cells will be connected in parallel to provide a proper capacity power.

-- Battery pack total energy (wh)
= No. of cells connected in parallel x Energy for battery pack (wh)
= 48 x 377.52
= 18120.96 wh or 18.120 kWh

-- Battery pack capacity
= No. of cells connected in parallel x Single cell capacity (Ah)
= 48 x 2.6 Ah
= 124.8 Ah

The value of battery pack capacity is used for the total power required by the vehicle.
-- Total number of cells for battery pack

= No. of cells connected in parallel x No. of cells connected in series

=48x44

= 2112

2112 Cells will be used to make a complete battery pack.
-- Mass of battery pack

= Total no. of cells for batter pack x Mass of single cell

= 2112 x 0.076 kg

= 160.512 kg

it is the total weight of cells connected in parallel and  series.

-- Total volume of the battery pack
= Total no. of cells for batter pack x Volume of single cell
= 2112 x 0.0345
= 72.89 m^3

This is the volume of2112 cells which are used in the battery pack system.

-- Cell peak current (A)
= C rate (Max Pulse Charge Current) x Single cell capacity
= 20 x 2.6
= 52 A

-- Battery pack peak current (A)
= Cell peak current x No. of cells connected in parallel
=52X48
= 2496 A

It is used for the operation of the battery pack. By this way, a vehicle will decide how much power is required to move.

-- Battery pack peak power (W)
= Battery pack peak current x Voltage of series connection
= 2496 A x 145.2
= 3624192 or 362.42 W

-- Cell continuous current (A)
= Crate (Max Continuous Charge Current) x Single cell capacity
= 10 x 2.6
= 26 A

-- Battery pack continuous current (A)

= Cell continuous current x No. of cells connected in parallel

= 26 x 48

= 1248 A

This is the power which is supply continue to the whole battery pack system.

-- Battery pack continuous power (W)

= Battery pack continuous current x Voltage of series connection

=1248 x145.2

= 18120.96 or 18.120 Kwh

detailed battery pack drawing along with its enclosure.

BATTERY HOLDER ,SPACER For CELL CYLINDRICAL LI-ION

Nickel Strips

Nickel strip is generally used in battery building. Its due to its efficiency of usage in spot welding and soldering as well its high corrosion resistance over time. It has good properties and excellent resistance to many corrosive environments. The pure nickel will never get rust after it applied to battery packs. It won’t affect the current transfer between batteries.

Pure nickel strips are the material you want, but many vendors swap out it for nickel-plated steel strips, which are poorer and have greater resistance – not suitable for most battery projects.

 100% pure nickel strip.  verify all of our strips to assure that you are getting the high-quality pure nickel. It also solder incredibly quickly, so you can weld them onto your existing busbar connections to raise the supply of current you can pull through the busbars. The benefits are nearly limitless!

battery enclosure

Design Benefits
• Up to 50 percent lighter than an equivalent steel design
• Best-in-class mass energy density at more than 160
watt-hours per kilogram, an extremely efficient design
for OEMs and Tier 1 battery pack manufacturers.
• Accommodates all battery cell types and is designed
particularly for battery electric vehicles with larger
power packs such as pick-up trucks, sport utility
vehicles and crossovers.
• Most cost-effective aluminum solution for mass
production electric vehicles when compared to
aluminum extrusion and casting-intense designs.
• Low price premium on $/kg saved compared
to equivalent steel designs at substantially
lower weight.

https://www.novelis.com/automotive/electric-vehicle-battery-enclosure/

as we know now 

Power (p)= Voltage (v) * Current (i) kw

3.3 *2.5 =8.25 kw

To get 18kwh ,we are assuming 48s 48p

i.e; 48*48 =2304 cells

series connection gives 48*3.3 =158.4 v
parallel connection gives 48* 2.5 =120 A
from this we can get

158.4* 120 =19.008 kwh energy or capacity.

we design battery pack for 48s and 48p cell along wth battery spacers to hold cells and for their connection nickel strip is used 

when cells are connected by nickel strip spot welding should be used so that cell not get damage. 

final form