One of the key components of Li-ion batteries is the busbar, which plays a crucial role in ensuring efficient and safe operation of the battery.
What is a Busbar?
A busbar is a thick, flat metal strip used to conduct electricity within a battery pack. In lithium-ion batteries, busbars are typically made from copper or aluminium and are used to connect the individual cells within the battery pack.
Why are Busbars Used in Lithium-Ion Batteries?
In a lithium-ion battery pack, each cell produces a voltage of around 3.6-3.7 volts. To create a higher voltage, cells must be connected in series, with the positive terminal of one cell connected to the negative terminal of the next cell. This creates a chain of cells, with the total voltage equal to the sum of the voltages of each cell.
However, connecting cells in series also creates a potential risk of overheating. If one cell in the chain fails or becomes damaged, it can cause an imbalance in the voltage of the other cells. This can result in overheating, which can cause a fire or explosion.
Busbars are used to prevent this from happening by providing a low-resistance path for current flow between the cells. This ensures that the cells are connected in a balanced way and reduces the risk of overheating and thermal runaway.
Types of Busbars Used in Lithium-Ion Batteries:
There are two main types of busbars used in lithium-ion batteries: rigid and flexible.
Rigid busbars: They are made from a single piece of metal and are used in applications where the battery pack is fixed in place and does not move. Rigid busbars are typically more efficient at conducting electricity than flexible busbars, but they are more prone to cracking and breaking if subjected to mechanical stress.
Flexible busbars: They are made from a thin strip of metal with a series of bends or folds. This design allows them to be more flexible and able to withstand mechanical stress, making them ideal for use in applications where the battery pack is subject to vibration or movement. However, flexible busbars are less efficient at conducting electricity than rigid busbars.