1. Advantages of parallel connection
Parallel operation can improve the energy storage capacity and carrying capacity, and ensure the running time and stability of the equipment to a certain extent. In addition, the parallel is also conducive to balancing the pressure difference between the battery cells, reducing the aging speed of the battery, and extending the service life of the battery.
2. Disadvantages of parallel connection
Parallel also has some disadvantages, of which the more obvious is that when the lithium battery with different capacity is connected in parallel, the battery with small capacity is easy to be overput, resulting in damage. In addition, if the quality of the battery is inconsistent, it is also easy to lead to overdischarge or overcharge of the battery.
Potential risks of parallel connection of lithium batteries of different capacities
Capacity difference problem : Lithium batteries with different capacities may behave differently during charging and discharging. A battery with a larger capacity may absorb more charge when it is charged and output more charge when it is discharged. This can cause smaller capacity batteries to overcharge and discharge, which can affect their life and performance. In the long run, batteries with small capacity may age faster and even be damaged.
Internal resistance difference problem : lithium batteries of different capacities usually have different internal resistance. In parallel, batteries with low internal resistance will bear more current, which can cause them to heat up more seriously and may even cause safety problems. If the internal resistance difference is large, it may also cause the current distribution inside the battery pack to be unbalanced, affecting the performance and life of the entire battery pack.
Consistency difference : lithium batteries with different capacities may have differences in the production process, such as electrode materials, manufacturing processes, etc. These differences may lead to inconsistent battery performance, such as charge and discharge curves, self-discharge rates, and so on. When used in parallel, these inconsistencies may affect each other, further exacerbating the instability of the battery pack.
Therefore, although it is possible, in order to ensure safe and efficient operation, it is best to use batteries with the same age, condition, voltage and capacity. The following are the safety precautions for battery parallel connection. If possible, choose a safer solution.
Safety precautions
1. Parallel lithium batteries of the same brand, model, and batch to ensure that their performance and parameters are as close as possible to reduce potential risks.
2. Before parallel connection, each lithium battery is fully tested and screened to ensure its good performance, no damage, no leakage and other problems.
3. Use a professional battery management system (BMS) to monitor the charging and discharging process of the battery pack to ensure the safe operation of the battery pack. The BMS can balance the charge and discharge of the battery pack to prevent excessive charge and discharge of individual batteries.
4. Ensure that the connection is correct and firm to avoid heating, ignition and other safety problems caused by poor contact.
5. Follow the operating specifications and safety requirements of lithium battery . Do not use the battery pack in high temperature, humid, or flammable environment.
