Calculate the number of series and parallel connections for lithium battery packs?

Series parallel connection of lithium batteries is particularly common in some PACK factories. Generally, lithium battery packs are composed of batteries in series parallel connection, which can be assembled into lithium battery packs of any voltage capacity.
For example, how many strings is the 48V20AH lithium battery pack?
When assembling lithium iron phosphate battery packs, different capacities and voltages are generally achieved through parallel or series connection. In a lithium battery pack, multiple lithium batteries are connected in series to obtain the required operating voltage. If higher capacity and greater current are required, then lithium batteries should be connected in parallel.
Lithium battery pack 48V20AH All lithium battery packs are composed of individual lithium batteries, which are connected in series or parallel; The way to increase voltage is to connect lithium batteries in series and add the voltages together;
Lithium battery pack 48V20AH generally has a single lithium battery of 3.5V. Therefore, a 48V lithium battery pack requires 48/3.5=13.7, and 14 batteries can be connected in series.
If the manufacturer has already provided a set of 12V lithium batteries, four can be connected in series. As long as the output voltage is 48V and the current is 2A or 4A, it is acceptable. If it takes about ten hours to fully charge 2A, this is when there is still a certain amount of power in the battery. If you buy a 4A, reduce the time by half and fill it up in about five hours.

How to calculate the number of strings and parallels required for a set of lithium batteries?
Calculation method one:
It's very simple. Series connection increases voltage, parallel connection increases capacity. The standard for ternary lithium batteries stipulates a voltage of 3.7V, fully charged with 4.2V, and three connections are 12V. 48V requires four triple connections. However, for electric vehicle lead-acid batteries, fully charged with 58V is the most important, so lithium batteries must also be around 58V. This requires 14 connections to 58.8V, multiplied by 4.2. For iron lithium batteries, fully charged with 3.4V, four connections must be 12V, 48V must be 16 connections, and so on. For 60V, 20 connections must be made, and for parallel connection of the same model and capacity, two 10AH batteries in parallel must be 20Ah. For 48V ternary lithium batteries, 14+14 10AH batteries must be used. The last 14 connected in series form a 48v20Ah lithium battery.
Calculation method 2:
In fact, it is very simple. For example, 48 volts usually refers to voltage. Generally speaking, ternary lithium batteries refer to 48 divided by 3.7. Thirteen and fourteen strings are basically considered 48 volts. Thirteen strings are charged with a 54.6 volt battery charger, while fourteen strings are charged with a 58.8 volt battery charger. So much so that 20 ampere hours usually refers to the capacity of the battery. If a single 18650 cell has a capacity of only 2000 milliamperes per cell, it is 2 ampere hours per cell. Ten cells combined together are 20 ampere hours, and the entire battery set is 14 series multiplied by 10 cells=140 cells.
Summary: Series and parallel have their own advantages for lithium iron phosphate batteries. The series and parallel connection of lithium battery packs have different goals due to different methods. Therefore, in actual use, they can be freely determined according to the desired goals, which can be set individually or combined in two ways to achieve the ultimate goal.

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