Ensuring Safety And Stability: Precautions in Parallel And Series Connections of Lithium Iron Phosphate Battery Packs

Parallel and series connection of lithium batteries is not just about connecting the lines in series and parallel. There are still many things to pay attention to in order to obtain a safe and stable series parallel successful lithium iron phosphate battery pack.

Before explaining the relevant precautions, I would like to briefly introduce parallel and series circuits, their definitions and characteristics.

Series circuit

The definition of a series circuit is to connect electrical appliances in sequence in a circuit. A circuit has only one path, and any open circuit will result in an open circuit, which is a characteristic of a series circuit.

Parallel circuit

Parallel circuit is one of the two basic ways to form a circuit, which allows for more than one independent path of current between the components that make up a parallel circuit. For example, a simple circuit containing two light bulbs and a 9V battery. If two light bulbs are connected to the battery separately by two sets of wires, the two bulbs are in parallel.

The characteristic of parallel circuits is that there are multiple paths in the circuit, each circuit is independent of each other, and one circuit component is open, while the other branches continue to work as usual.

The reasons for parallel and series connection of lithium iron phosphate batteries

Connect multiple lithium iron phosphate batteries in series in a lithium battery pack to obtain the required operating voltage. If higher capacity and greater current are required, then the lithium batteries should be connected in parallel first. The combination of series and parallel methods can achieve high voltage and high capacity standards.

To obtain more power, multiple batteries can be connected in parallel. Another method, besides connecting the batteries in parallel, is to use larger batteries. Due to the limitations of the available batteries, this method is not suitable for all usage situations. In addition, large-sized batteries are not suitable for the appearance specifications required for specialized batteries.

Most chemical batteries can be used in parallel, and lithium-ion batteries are most suitable for parallel use. When using the series parallel connection method, it is very flexible in design and can achieve the required rated voltage and current using standard battery sizes.

Precautions for parallel and series connection

In terms of internal resistance

When connecting lithium iron phosphate batteries with significant differences in internal resistance in parallel, it is best to discharge them separately and not directly in parallel. Because parallel connection with a large difference in internal resistance is not conducive to lithium batteries with low internal resistance.

Single lithium battery failure

Connecting multiple lithium iron phosphate batteries in series in a lithium battery pack can achieve higher operating voltage. If you want higher capacity and current, you can choose to connect the lithium batteries in parallel.

However, in order to pursue higher voltage and current, many lithium batteries are connected in series and parallel. This type of high-voltage lithium battery pack is prone to encountering a situation where one of the batteries in the battery pack fails.

It is not an easy task to replace faulty lithium iron phosphate batteries. It is easy for new and old batteries to have mismatches because the capacity of new batteries is much higher than that of old batteries.

Lithium battery protection board

When conducting series and parallel connection of lithium iron phosphate batteries, it is best to configure a protection circuit, namely a lithium battery protection board. Because the lithium battery protection board can be used to monitor the status of each battery connected in series.

Using lithium batteries in series and parallel may sound simple, but it is necessary to follow some simple rules to avoid unnecessary problems.