Project 1 Mechanical design of battery pack

Project 1 Mechanical design of battery pack

Battery pack capacity: 18 kWh

Cell: ANR26650M1-B

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

Answer: -

Aim: - Mechanical design of battery pack using datasheet cell: ANR26650M1-B and Battery capacity are 18 kwh.

Datasheet:

We can download the Cell Datasheet Cell: ANR26650M1-B we can see

Cell specification:

Constant current discharge and Constant power discharge

Cycle Life Performance

Calculation:

We can see the datasheet, in this datasheet we can see the technical specification current capacity, voltage of cell.

we can calculate the battery capacity

Assumption:

Battery energy: 18 kWh
Vehicle run Voltage: 400 V

Now calculate the Number of cell(N) : energy/(Nominal voltage*Capacity)

N : 1800/(3.3*2.5)

N : 2182

Now, the Vehicle run voltage are 400V and total cell required 2182. We need to decide series or parallel configuration

Now, cell connect series connection voltage required 400V(Ns)= voltage required/ nominal voltage of the one cell.

Ns = 400/3.3

Ns =121.21

122 cells required for connect the series and will get 400V voltage and capacity of model 2.5Ah.

Now we need Cell connected parallel (Ns)

Ns = Total cell/ series connected cell

Ns = 2182/122

Ns =17.88 =18

Battery capacity of parallel Configuration cell

Capacity = Parallel cell row*individual cell capacity
Capacity = 18 * 2.5
Capacity = 45Ah

Theory:

The 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 Werks’ 26650 cells are best for Power.Safety.Life.™ applications. They deliver very high power due to their 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 thermal-stable chemistry, faster charging, consistent output, low capacity loss over time, and superior total cost of ownership (TCO). 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.

Cell arrangement as per requirement:

Series cell connection: -

We can see the cell arrangement all same rating and same type cell are connected in series.

parallel cell connection: -

We can see the above cell arrangement, if the same type of cell are connected in parallel arrangement.

Cell welding:

in a battery pack, hundreds and sometimes thousands of welds are needed to make the connections from the cells to the terminals. Tabs and terminals are not only connected to busbars and collector plates, but also to current collectors inside the cells.

The quality of these connections is crucial to the quality of the battery, where even a 1% fail rate is a serious issue. Appropriate measures must be taken to guarantee that surfaces are clean before welding, such as preparing them with leaser cleaning or working in a controlled environment.

Ultrasonic Welding: -Ultrasonic bonding, or ultrasonic welding, uses ultrasounds to create vibrations between the materials to be joined. The rapid friction between the materials generates enough heat to join them almost instantly.

This technology is used for foil-to-tab welds as well as to connect cells to busbars via wires, a method known as ultrasonic wire bonding.

Laser welding: Laser welding is a high-speed process that uses a highly focused beam of light to join surfaces. The laser beam is directed and moved using ultrafast moving X-Y mirrors. This provides a lot of flexibility, making it possible to weld any joint geometry as well as custom weld patterns.

Pulsed fiber lasers are the lasers of choice for battery welding because they lead to smaller heat affected zones, lower porosity, and less spatter. They can weld thin or thick tabs, and process copper, aluminum, steel, and nickel as well as dissimilar materials.

Resistance welding: -Resistance welding, also called spot welding, is a method that uses copper or tungsten electrodes charged with electrical current to perform the welding. As pressure is applied on the area to be welded, an electrical current is passed through the electrodes. This generates heat at the contact area and bonds the two metals together.

Resistance welding can be used for foil-to-tab and tab-to-busbar welds. It is a cost-effective welding process that is ideal for DIY battery enthusiasts, but it can be automated as well.

Battery Management system: -

Battery management system are main function:
-Battery protection in order to prevent operations outside its safe operating area.
-Battery monitoring by estimating the battery pack state of charge (SoC) and state of health (SoH) during charging and discharging.
-Battery optimization thanks to cell balancing that improves the battery life
and capacity, thus optimizing the driving range for hybrid (HEV), plug-in (PHEV) and full electrical vehicles (BEV).

Conclusion: -

We can see the Li-ion battery pack (ANR26650M1-B) are greater power source, also we ca see the all battery calculation, cell arrangement and battery management system.S