What should be paid attention to when connecting Lithium Ion Battery batteries in series and parallel?

Precautions for Lithium Ion Batteries batteries in series and parallel

• Do not use batteries of different brands together.
• Do not use batteries of different voltages together.
• Do not mix different capacities or old and new lithium batteries.
• Batteries of different chemical materials cannot be mixed, such as nickel-metal hydride and lithium batteries.When the lithium ion batteries power is low, replace all batteries.
• Use the lithium battery protection board with the corresponding parameters.
• Choose batteries with the same performance. Generally, lithium batteries need to be paired in series and parallel. Matching standard: voltage difference≤10mV, internal resistance difference≤5mΩ, capacity difference≤20mA

1. Lithium batteries of different voltages are connected in series

Due to the consistency problem of lithium batteries, if the same system (such as ternary or iron-lithium) is used in parallel and series, it is also necessary to select the same voltage, internal resistance, and capacity for matching. Batteries with different voltage platforms and different internal resistances are used in series, which will cause a certain battery to be fully charged first and then discharged in each cycle. If there is a protection board and there is no failure, the capacity of the whole group will be reduced. Damage to the battery caused by overcharging or overcharging.

2. Lithium ion batteries of different capacities are connected in parallel

If different capacities or old and new lithium ion batteries are used together, there may be liquid leakage, zero voltage and other phenomena. This is due to the difference in capacity during the charging process, which causes some batteries to be overcharged during charging, while some batteries are not fully charged. When discharging, some batteries with high capacity are not fully discharged, while those with low capacity are overdischarged. Such a vicious cycle, the battery gets damaged and leaks or has low (zero) voltage.