22.2V 2500mAh 18650 Li-ion Battery Pack

Hlcbattery is a premium lithium battery supplier in China. Our core business covers 18650 batteries, lifepo4 batteries and li-polymer batteries.

Lithium rechargeable battery module composition:

Serial and parallel composition: The battery is formed by connecting single cells in parallel. Parallel connection increases the capacity, the voltage remains the same, and the voltage doubles after the series connection, the capacity remains the same. For example, a 3.6V/10Ah battery is composed of a single N18650/2Ah through 5 parallels. Parallel first and then series: Parallel connection will affect the cycle life of batteries after parallel connection due to differences in internal resistance and uneven heat dissipation.

However, the failure of a single battery automatically exits, except for the capacity reduction, it does not affect the use after parallel connection, and the parallel connection process is stricter.

When a unit battery in parallel is short-circuited, the parallel circuit current is very large, which is usually avoided by adding fuse protection technology.

First in series and then in parallel: according to the capacity of the entire battery pack, first connect in series, such as 1/3 of the entire battery pack capacity, and finally connect in parallel, which reduces the failure probability of large-capacity battery packs.

18650 cell requirements:

Select the corresponding cells according to your own design requirements. The batteries in parallel and series require the same type and model, and the difference in capacity, internal resistance and voltage value is not more than 2%. Under normal circumstances, after the batteries are combined in parallel and series, the capacity loss is 2%-5%. The more the number of batteries, the greater the capacity loss.

Whether it is a soft package battery or a cylindrical battery, multiple strings are required. If the consistency is poor, the battery capacity will be affected. The battery with the lowest capacity in a group determines the capacity of the entire battery group. High current discharge performance is required. The starting current of the motor is 3 times of the normal working current, and the power performance of the motor can be improved only by high current discharge. The battery is required to have good heat dissipation. With a large number of batteries, the temperature rise of the batteries inside the battery box is not easy to dissipate, resulting in uneven temperature among the batteries, different discharge characteristics, and long-term battery performance degradation. The production technology level is high.

The battery must be able to withstand the vibration shock of bumpy road surfaces. The production process, especially the spot welding process, has high requirements. After welding, test to prevent virtual welding and de-soldering.

The process of lithium battery module:

Lithium battery module is realized in two ways, one is through laser welding or ultrasonic welding or pulse welding, which is a commonly used welding method. The advantage is that the reliability is good, but it is not easy to replace. The second is to contact through elastic metal sheets. The advantage is that no welding is required, and the battery is easy to replace. The disadvantage is that it may lead to poor contact.