Energy storage serves as the best substitute for any power generating system that offers energy-based solutions. And batteries are the key component that fulfills the demand of energy utilization of any form.
Batteries are considered the lifeforce of an electrified device or component that works with electric energy and comes under the category of green energy source.
Due to its extremely low pollution emission features, lithium-ion batteries are garnering high popularity in the electric vehicle (EV) space.
Battery Pack is the collective term engineers often use to describe the battery system of any EV.
To get a better understanding, we are going to discuss What is a Battery Pack and Why is Battery Pack used in Electric Vehicle?
What is a Battery Pack?
Before getting a clear definition of What is a Battery Pack, check out this simple composition of how we differentiate Battery packs in an electric vehicle.
Cell → Module → Pack
Since every electric vehicle requires a required set of battery cells in a connected manner, the term battery pack is used for radio-controlled hobby toys, cordless tools and battery electric vehicles.
Typically, a battery pack is defined as a set of any number of identical batteries or individual battery cells.
Generally configured in a series, parallel, or mixture, the battery pack enables the delivery of desired voltage, capacity, or power density.
Specific for any application, a range of varying components and battery chemistries can be configured that dictate the types of standard materials, an engineer will use for a specific requirement.
Additional components may also be added to perform a specific function in an electric vehicle Battery Pack.
Whenever basic materials are considered, a battery engineer needs to determine the type of battery chemistry that will be appropriate according to the functionality of the device or vehicle.
Generally, every battery is composed of anodes, cathodes and electrolytes, however, these components will be made of specific materials based on whether a customer chooses a lithium-based battery, nickel-based battery or an alkaline battery.
For a lithium-ion battery cell, the components required will include an anode made from lithium, lithium-alloying materials, graphite, intermetallic, and silicon and a cathode made of lithium-metal oxides, rechargeable lithium oxides, olivine, and vanadium oxides.
Apart from the electrolyte used to make a cell, a separator is required to keep the cathode and anode separate and the separator will be made of foam material in the case of a lithium-ion cell.
Finally, the lithium-ion battery cell will be covered in several seal layers wherein each battery within the pack will have specific interconnections internally as well as externally.
In a Battery Pack, the material used for these connections depends on whether the battery pack offers high power or low power as its application.
Around 12 cells are normally arranged into a conventional battery module for EVs and the capacity ranges around 2~3 kWh.
Battery regulators are also used to keep the voltage of each cell below its maximum value during charging.
This allows the weaker batteries to become fully charged while bringing the whole pack back into balance.
Why Use Battery Pack for EVs?
If you open a Battery Pack of any electric vehicle, you will observe egg-like cells scattered in a regular shape and size. These egg-shaped cells are typically arranged in series or parallel configurations to provide fixed voltages and capacities.
If you need more voltage, you have to deal with multiples of the cell voltage and have to add them in series, however, if you need less voltage, you need some kind of voltage regulator or DC/DC converter.
Similarly, if you need more current, you may need to put cells in parallel and for more capacity and longer run time you can also put cells in parallel.
Perks of Battery Pack
Stating some of the common benefits a battery pack offers include,
- Ease of swapping
- Flexibility in design and implementation
- Recyclable in nature