How to make 3.2v lithium ion cells to 12v battery packs?

lithium ion cells are the basic building blocks for lithium ion battery packs. In this blog, we will take prismatic 3.2v lithium cells making 12v battery packs for example to explore how is the professional manufacturer to produce the lithium ion battery packs.

lithium ion cell to pack

Two connections of  lithium ion cells

1.cells in series

When assembly the lithium ion cells to series connections, lithium ion battery packs won’t change the amp-hour rating, but will raise the voltage of the battery system. Please always keep in mind that with series connections, each battery needs to have the same voltage and capacity rating, or you can end up damaging the battery. In this kind of connection, the positive terminal of a 3.2v lithium cells is connected to the negative terminal of the next cell until the desired voltage is achieved. For instance, if we want a battery packs 12v, we need to use 4pcs 3.2v 100ah lifepo4 rechargeable battery cells with series connection.

2. lithium ion cells in parallel

When connecting 3.2v lithium cells in parallel, the positive terminals are connected together, and the negative terminals are connected together until the required capacity is reached. Parallel connection means connecting 2 or more 3.2v lifepo4 battery cells together to increase the ampere hour capacity of the battery pack, but the voltage remains the same. Therefore, two 3.2v 100ah battery cells in parallel connection would create a 3.2v lifepo4 battery 200ah pack.

Professional laser weldinglaser welding battery packs

Laser welding is a good choice for joining battery tabs during prismatic lithium ion cells to battery pack assembly. The process is fast and efficient. It produces high-strength welds for all material combinations. The process is easily adapted to a broad range of joint designs. Ordinary welding techniques can cause heat damaging the anode/cathode. But with laser welding, there is no heat damaging the anode/cathode. It is the most advance technology for welding 3.2v lifepo4 rechargeable battery cells. So, for this reason, most professional manufacturer are use laser welding to assembly the 3.2v lithium cells. As to our OSM company, we also use this technology to make 3.2v lifepo4 cells to 12v or 48v battery packs.

The battery packs controller, BMS

When a lithium-ion cell is fully charged, its voltage begins to rise further, which may lead to electrode damage. If the charge of the entire battery is stopped when only one cell is fully charged, the remaining cells do not reach full charge and the battery will operate below peak capacity. A well-designed BMS will ensure each cell safely and fully charges before the entire charging process is complete.

BMS just like the brain of 12 volt lithium ion battery packs which monitors and manages all the battery’s performance. It manages real-time control of each battery, communicates with external devices, manages SOC calculations, measures temperature and voltage, and so on. The selection of BMS determines the quality and life of the final rechargeable battery packs.


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