Series and parallel connection of lithium battery pack modules

What are the Connection modes of a lithium battery pack?

The typical connection modes of a lithium battery pack are connecting first in parallel and then in series, first in series and then in parallel, and finally, mixing together. Lithium battery pack for pure electric buses is usually connected first in parallel and then in series.

What happens if a lithium-ion battery is connected parallel?

Uneven electrical current distribution in a parallel-connected lithium-ion battery pack can result in different degradation rates and overcurrent issues in the cells. Understanding the electrical current dynamics can enhance configuration design and battery management of parallel connections.

Why do lithium ion batteries need to be connected in series?

To meet the power and energy requirements of the specific applications, lithium-ion battery cells often need to be connected in series to boost voltage and in parallel to add capacity . However, as cell performance varies from one to another [2, 3], imbalances occur in both series and parallel connections.

What is a large-format lithium-ion battery pack?

Conferences > 2014 IEEE International Elect... Large-format Lithium-ion battery packs consist of the series and parallel connection of elemental cells, usually assembled into modules. The required voltage and capacity of the battery pack can be reached by various configurations of the elemental cells or modules.

Why are parallel lithium-ion battery modules important?

Parallel lithium-ion battery modules are crucial for boosting the energy and power of battery systems. However, the presence of faulty electrical contact points (FECPs) between the cells often leads to severe performance degradation, including reduced capacity, accelerated aging, and the potential risk of thermal runaway.

Why do batteries need series and parallel connection?

Due to the limited voltage and capacity of the single battery cell, the series and parallel connection is needed in the actual use to obtain higher voltage and capacity, so as to meet the actual power demand of the equipment. Add the voltage of batteries, capacity remains the same, and internal resistance increases.