Project 1 Mechanical design of battery pack
Aim: -
To Prepare a detailed battery pack drawing along with its enclosure, with a battery pack capacity of 18kWh using the cell model ANR26650M1-B
Battery and Battery Pack: - Batteries are made up of one or more cells whose chemical reactions produce an electron flow in a circuit. Every battery has three basic components: an anode (the '-' side), a cathode (the '+' side), and some kind of electrolyte (a substance that chemically reacts with the anode and cathode).
When a battery's anode and cathode are connected to a circuit, a chemical reaction occurs between the anode and the electrolyte. This reaction sends electrons through the circuit and back to the cathode, where another chemical reaction occurs. When the material in the cathode or anode is depleted or no longer usable in the reaction, the battery is unable to produce electricity
Battery packs are any number of individual batteries connected in series or parallel to power electronic devices. Because of their high power density, lithium ion batteries are the most commonly used type of battery in battery packs. Battery packs are used in a variety of applications, including phones, lawn mowers, and automobiles.
A123’s high-performance 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. Our 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 our systems to meet end-of-life power and energy requirements with minimal pack oversizing.
Battery Calculation
The energy requirement is 18kWh as per the given data, normally used voltage of an EV battery Pack is 400V/800V here we are selecting 400v to design the battery pack.
Then Energy =18kWh
While using 400v,
the number of cells to get 400V = 400/3.3 ( here 3.3 is the nominal voltage of the battery used)
=121.2 to get a minimum value of 400V adding one more cell then the number of cells in series is =122
Then to calculate the number of battery packs connected in parallel
=18000/(402.6 X 2.5)
=17.88
=18
Then the Ampere capacity =18*2.5
=45
Total number of cells used =122*18=2196
Each cell have a diameter of 26mm and a length of 65mm
Series Strings:- Cells combined in series strings can achieve higher operating voltages by connecting the positive terminal of one cell to the negative terminal of the next cell. Connect strings of series cells using their current collection tabs in a manner similar to as shown below
Parallel Strings: - Cells combined in parallel strings can achieve higher operating capacities by connecting like-polarity terminals of adjacent cells to each other. Connect strings of parallel cells using their current collection tabs in a manner similar to that shown below
Here 122 cells are connected in series to get 402.5 voltage and 18 number of 402.5 voltage batteries are connected in parallel to get the 18kWh energy.
Nickel strip: -it is generally used in battery building. It's due to its efficiency of usage in spot welding and soldering as well as 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 is 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 solders 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 battery pack image is shown below
While assuming the overall volume of the battery pack will be near 103915cm3