Why do batteries need to be connected in parallel

The purpose of paralleling lithium batteries is to increase the capacity. The characteristics of parallel lithium batteries are: the voltage remains the same, the battery capacity is added, the internal resistance is reduced, and the power supply time is extended. The internal resistance of the batteries in parallel will also change, and the parallel resistance will decrease as the number of batteries in parallel increases.

When connecting lithium batteries in parallel, attention should be paid to the consistency of the batteries, because lithium batteries with poor consistency will fail to charge or overcharge during the charging process, which will damage the battery structure and affect the life of the entire battery.

After the batteries are connected in series, the voltages are added, and the currents are equal, which increases the voltage; the batteries are connected in parallel, and the voltage remains the same (provided that the batteries with similar voltages can be connected in parallel), and the current is equal to the sum of the batteries, which can often be regarded as an increase Increase the battery capacity, and can provide more current.

The difference between battery series and parallel:

Lithium batteries in series:

It means that the lithium battery is connected end to end. That is, the positive electrode of the first battery is connected to the negative electrode of the second battery, the positive electrode of the second battery is connected to the negative electrode of the third battery, and so on; the series voltage is equal to the sum of the battery voltages, and the current is equal to the current flowing through each battery; Damage to a section of the battery pack will cause the entire battery pack to be unusable or the voltage drop; series connection can increase the total voltage.

Battery parallel:

Refers to the battery's first-to-first connection and end-to-end connection. That is, the positive poles of all batteries are connected, and the negative poles of all batteries are connected. The parallel voltage is equal to the voltage of a single battery, and the current is equal to the sum of the battery currents. Although the endurance of the battery pack is enhanced, the damage caused by the short-circuit current is more serious; the parallel connection can increase the total current. Whether in series or in parallel, the output power of the battery pack increases.