Assembly Process And Method Of Lithium Ion Battery Pack

Assembly Process And Method Of Lithium Ion Battery Pack

Assembly process of lithium ion battery pack

The PACK of lithium-ion batteries is realized in two ways. One is through laser welding or ultrasonic welding or pulse welding. This 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.

Assembly method of lithium ion battery pack

①Serial and parallel composition: The battery is composed of single cells connected in parallel. The new capacity is added in parallel, and the voltage is unchanged. After the series is connected, the voltage is doubled and the capacity is unchanged. 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 current of the parallel circuit is very large, and fuse protection technology is usually added. 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 capacity, and finally connect in parallel, which reduces the failure probability of large-capacity battery packs.

② Battery cell requirements: select the corresponding cell according to your own design requirements. The parallel and series batteries 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% and 5%. The more the number of batteries, the greater the capacity loss. Whether it is a soft-packed battery or a cylindrical battery, multiple strings must be combined. 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 group of batteries. High current discharge performance is required. The starting current of the motor is three times that 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. High level of processing technology. The battery must be able to withstand the vibration shock of bumpy road surfaces. The processing technology, especially the spot welding process, has high requirements. After the welding is completed, the detection is carried out to prevent false welding and de-soldering.