How to determine battery pack consistency?

First, the capacity of each cell in the battery pack Qi, the difference in remaining chargeable capacity of each cell when the battery pack reaches the charge cutoff condition Qdi, and the internal resistance of each cell Ri are determined to accurately characterize the battery pack consistency.

What are battery pack consistency evaluation indicators?

Currently, the battery pack consistency evaluation indicators are unclear and are roughly divided into single-parameter and multi-parameter evaluations. Single-parameter evaluation usually uses voltage or SOC to characterize the consistency of the battery pack .

Are lithium-ion batteries safe?

With the prevailing application of lithium-ion batteries, the durability and safety for battery packs receive more and more attentions from researchers and engineers since the improper usage of batteries will shorten the battery life , , , and even sometimes cause severe fire hazards , .

What is the nominal capacity of a battery pack?

The nominal capacity of the battery pack is 105Ah, three cells with nominal capacity of 35 A h in parallel constitute a battery module, and 104 battery modules are then serially connected composed of the battery pack. The bus is off grid when parked at night, and the battery pack are not be charged when standing by.

What is the average OCV of a lithium-ion battery?

Most OCV values are between 3.95 V and 4.15 V. The SOC-OCV curve of the lithium-ion battery is illustrated in Fig. 4. It can be inferred that before the start of the bus every day, the SOC is mainly distributed ranging from 60% to 95%, which is in a high SOC region. Fig. 3. Histogram distributions of average OCV for Bus #1 and Bus #2. Fig. 4.

What happens if two batteries have the same charged capacity?

The above curves are reconstructed under the assumption that the two batteries have the same charged capacity within the same voltage growth window. However, if the charged capacities are different, errors will be introduced when the voltage curve of #1 is shifted to the right to the voltage curve of #2.