Understanding Battery Connections: Series vs. Parallel

Properly configuring batteries in series and parallel may seem straightforward, but adhering to some fundamental guidelines is crucial to avoid unnecessary complications.

In a battery pack, the manner in which you connect multiple cells can significantly impact the desired operating voltage, capacity, and current. When a higher capacity and increased current are required, cells should be connected in parallel.Battery recycling machine In some cases, battery packs employ a combination of series and parallel connections. For instance, a laptop battery may feature four 3.6V lithium-ion batteries connected in series to achieve a total voltage of 14.4V. Additionally, two more sets of batteries, connected in series, are then linked in parallel to double the overall battery capacity from 2,000 mAh to 4,000 mAh. This type of connection is often referred to as "four series and two parallel," signifying the connection of two sets of four batteries in series and then connecting these two sets in parallel.

Series Connection

Devices that require higher power levels are typically powered by battery packs consisting of two or more batteries connected in series. Utilizing high voltage batteries allows for smaller conductors and switches, reducing overall size.cylindrical battery pack mahcine Common examples include moderately priced industrial power tools with battery voltages ranging from 12V to 19.2V and advanced power tools with voltages from 24V to 36V. The automotive industry has also raised starter ignition battery voltages from 12V (typically 14V) to 36V or even 42V, using battery packs made up of 18 lead-acid batteries connected in series. Some hybrid vehicles have utilized battery packs with voltages as high as 450V to 500V, primarily using nickel-based chemistries. For instance, a nickel-metal-hydride battery pack with a voltage of 480V comprises 400 nickel-metal-hydride cells connected in series. High voltage batteries can pose challenges, including arcing on switches and the risk of cell failure within the pack.

Parallel Connection

Connecting two or more batteries in parallel is an effective way to increase power. It can be an alternative to using larger-sized batteries, which may not be suitable in all scenarios due to battery limitations and form factor requirements.cell stacking machine Most battery chemistries are compatible with parallel connections, and lithium-ion batteries are particularly well-suited for this purpose. For instance, a battery pack consisting of four cells connected in parallel maintains a voltage of 1.2V while increasing current and runtime by a factor of four.

Series-Parallel Connection

Series-parallel connection offers flexibility for achieving the necessary voltage and current ratings using standard battery sizes. It is important to note that the overall power remains constant, as power is equal to voltage multiplied by current.

Lithium-ion batteries frequently use series-parallel connection methods. A common example is the 18650 battery (18mm in diameter and 650mm in length) with a protection circuit, resulting in a maximum voltage of 14.4V when connected in series. This protection circuit can also monitor the status of individual cells in parallel.

In series-parallel connections, it is crucial to distinguish between the battery state and the characteristics of series and parallel connections. Always ensure correct polarity and avoid mixing them up. Series connections increase voltage while maintaining capacity, whereas parallel connections increase capacity while keeping voltage constant.