For battery packs, balance is an eternal topic because battery cells are always used in series and parallel.
At present, there are two main types of equilibrium schemes, passive equilibrium and active equilibrium, each with its own advantages and disadvantages. The specific use needs to be combined with the actual situation.
Passive balancing is widely integrated into BMS due to its low cost and simple solution, but its balancing ability is generally weak, less than 100mA, making it very suitable for battery cells within 3 years. The widespread integration design of passive balancing also indicates that it is very suitable for the initial investment in battery packs. Currently, Enjie Electronics' conventional BMS boards all integrate passive balancing function.
Active balancing is relatively complex and costly, but its balancing ability is strong (generally 200mA to 5A), making it more suitable for cells that have already experienced attenuation.
In terms of active balancing design, active balancing can be divided into two directions:
1) Integrated on the BMS board, with relatively weak balancing current, typically around 1A;
2) External independent balancing board, with strong balancing ability, generally above 1A.
Compared with passive balancing, active equalization technology transfers energy from higher-voltage cells to lower-voltage cells instead of dissipating excess energy as heat. This approach helps improve battery pack efficiency and maximize available energy capacity. In many battery systems, an active equalizer is used to achieve this energy transfer process efficiently.
1. Higher Balancing Efficiency
Active equalization reduces energy loss during the balancing process because energy is redistributed among cells rather than converted into heat. This improves the overall energy utilization of the battery system.
2. Faster Cell Balancing
With balancing currents typically ranging from several hundred milliamps to multiple amps, active balancing can correct cell inconsistencies much faster than passive balancing, especially in large-capacity battery packs.
3. Extended Battery Life
By maintaining better consistency among battery cells, active equalization helps reduce stress on individual cells, slowing capacity degradation and extending the overall service life of the battery pack.
4. Improved Available Capacity
When cell voltage differences are minimized, the battery pack can utilize more of its available energy. This helps improve system runtime and overall battery performance.
5. Suitable for Aging Battery Packs
As battery packs age, cell inconsistency tends to increase. Active balancing provides stronger correction capability, making it particularly beneficial for battery systems that have already experienced some degree of capacity fade. This is particularly valuable for users looking for a reliable bms solution over the long term.
6. Better Performance in Large Energy Storage Systems
For residential, commercial, and industrial energy storage applications, active equalization helps maintain long-term battery consistency and improves overall system reliability, especially in battery packs containing a large number of cells connected in series.
Enjie Electronics' active balancing scheme is an external independent balancing board with an average current of 3A and strong balancing ability. In addition, the design of an external independent balancing board also avoids significant upfront investment for end customers. In addition, this board integrates Bluetooth function, allowing customers to easily use Bluetooth for information acquisition and control.
