What you need to know about lithium battery balancing

In the application of lithium batteries, we can often need to single lithium battery enterprise for a series and parallel connection, in order to component parts of different working voltage and capacity of the battery pack for research use. However, due to each battery development own management there are certain differences in the use of this process, the voltage and capacity of each battery will also have to understand the different (this cultural differences will gradually increase with the social time and environmental changes). In the charging and discharging process of the battery pack, due to the existence of the barrel effect, the lowest capacity of a single battery will limit the ability of China's entire battery pack discharging and charging technology, which in turn affects lead to the reduction of the company's overall market capacity.

In order to solve the above problem, equalization function is usually added to the design of protection board or battery management system. The primary function of equalization is to deplete or transfer the charge of pre-charged individual cells during the charging and discharging process so that other unfilled or empty individual cells can continue to be charged to ensure that the entire battery pack can be more fully charged.

Passive equalization, also known as energy dissipative equalization, works by connecting a resistor in parallel with each cell. When a single cell has been fully charged ahead of time and it is necessary to continue charging the pack, the excess energy is dissipated by connecting the resistor and discharging it. This buys more charging time for the other cells before the battery charge is protected.

Active equalization, also known as non-energy-dissipating equalization, is based on the transfer of energy from pre-filled to unfilled cells to ensure that each cell in the pack can be filled. Since active equalization does not drain the capacity of the cells, it also works during the battery discharge process.

Simply put, Li-ion battery equalization is about ensuring the overall performance and life of the battery pack so that the other individual cells can continue to be charged by depleting or transferring energy from the pre-filled individual cells. Passive equalization consumes excess energy through parallel resistance, while active equalization transfers energy to cells that are not yet full. These equalization techniques are important for improving the performance and extending the life of a battery pack.