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.
FOR ANR26650M1-B
Choosing the Right Battery Strips
To make the battery pack, you have to connect the 18650 cells together by means of Nickel strips or thick wire. Generally, Nickel strips are widely used for this. In general two types of nickel, strips are available in the market: nickel-plated steel strips and pure nickel strips. I will suggest buying a pure nickel. It is a little bit costlier than nickel-plated steel, but it has much lower resistance. Low resistance means, less heat generation during the charging and discharging, which leads to longer useful battery life.
Nickel strips come with different dimensions and lengths.
Battery Pack Capacity and Voltage
To make the battery pack, we first finalize the nominal voltage and capacity of the pack. Either it will be in terms of Volt, mAh/ Ah, or Wh. we have to connect the cells in parallel to reach the desired capacity (mAh ) and connect such parallel group in series to achieve the nominal voltage (Volt ).
Assemble the Cells
From the previous step, it is clear that our battery pack is made up of 55 parallel strings, and each parallel string has 37 cells in series . Now we have to arrange the 15 cells properly for making the electrical connection among them and with the BMS board.
Place the first parallel group of cells (5 nos) positive side up, then place the second parallel group negative side up, and then finally the last parallel group positive side up.
1. We can make a custom pack of any size according to your requirement.It's like solving a puzzle.
2. It provides space between the cells, which allow fresh air to pass and the battery gets cooled easily.
3. It makes your battery pack solid and reliable.
4. It provides safety anti-vibration to your battery pack
A battery management system (BMS) is an electronic system that manages a lithium battery pack and the main functionalities are
1. Monitors all of the parallel groups in the battery pack and disconnect it from the input power source when fully charged ( near 4.2V )
2. Balance all the cells voltage equally
3. Doesn't allow the pack from over-discharged