Matching of 5 series and 2 parallel lithium battery packs

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 series and parallel battery configuration?

Batteries may consist of a combination of series and parallel connections. Cells in parallel increased current handling; each cell adds to the ampere-hour (Ah) total of the battery The EarthX ETX680 is an example of a series and parallel configuration. The ETX680 configuration, 13.2V / 12.4Ah, is shown in Figure 2.

Do multi-pack batteries need to be matched?

Cells in multi-packs must be matched, especially when used under heavy loads. (See BU-803a: Cell Mismatch, Balancing). The single-cell configuration is the simplest battery pack; the cell does not need matching and the protection circuit on a small Li-ion cell can be kept simple.

How does a parallel connection increase battery capacity?

Parallel connection attains higher capacity by adding up the total ampere-hour (Ah). Some packs may consist of a combination of series and parallel connections. Laptop batteries commonly have four 3.6V Li-ion cells in series to achieve a nominal voltage 14.4V and two in parallel to boost the capacity from 2,400mAh to 4,800mAh.

Can I connect two batteries in a series configuration?

Both batteries in a series configuration must have the EXACT same load, meaning you cannot connect a load to just one battery in the series. If you charge one battery you must charge the other to an equal charge level. If you replace one battery, you must replace the other battery. See the example below for series wiring (Figure 5).