Environmental pollution and energy crises are gradually becoming two major challenges of the 21st century. With increasing environmental awareness and strong government support, electric vehicles, with their energy-saving and environmentally friendly characteristics, have gained market favor and will undoubtedly lead the future development of the automotive industry. Batteries, as the core component of electric vehicles, determine the possibility of further development. Due to technological limitations, the power battery of an electric vehicle is composed of multiple single cells connected in series. The inconsistency of individual cell performance and severe overcharging and over-discharging during use significantly affect the battery pack's lifespan.

Therefore, battery balancing technology is crucial for the industrial development of electric vehicles. Applying battery balancing technology to charging stations to ensure the safe and effective charging of the battery pack each time is one way to solve the problem of battery pack lifespan degradation. The latest domestic and international data show that non-dissipative balancing technology is currently the focus of research, exhibiting a diversified circuit structure and a variety of control methods. However, many balancing methods remain at the theoretical research stage and do not fully consider parameter changes in the actual working environment of the battery pack. Furthermore, some proposed balancing control strategies are often too complex to be applied in practice.

Based on an in-depth analysis of domestic and international research on power battery pack balancing technology, Enerkey BMS has developed an active bidirectional DC-DC battery equalizer design method specifically for the incomplete charging and overcharging situations that often occur during electric vehicle charging. This method can achieve complete charging of lithium battery packs and can balance the charging of a battery pack composed of 24 lithium cells. The designed battery balancing system consists of two parts: the balancing main circuit and the balancing controller. First, the circuit design of the balancing main circuit and controller is described in detail. With the goal of designing a product-level battery equalizer, the circuit design methods for the power supply circuit, power monitoring circuit, DSP peripheral circuit, SPI module, and CAN module are discussed. The balancing controller uses a DSP as the control core, supplemented by Linear Technology's LTC6804-2 voltage acquisition module. Secondly, a complete solution from battery voltage monitoring to individual cell voltage balancing of the battery pack is designed, along with an effective balancing strategy. SOC estimation algorithm; subsequently, a simulation model of the battery balancing system was established, and the balancing scheme was verified through simulation. Finally, a prototype of the battery balancer was developed and subjected to electromagnetic compatibility, high and low-temperature tests, and functional tests to verify the effectiveness and reliability of the entire system design.

For the balancing problem of series-connected lithium-ion batteries, we proposed an intelligent battery balancing scheme based on fuzzy logic control. This battery balancing scheme consists of a bidirectional DC-DC controller with an energy transfer capacitor, which can be used to design a lossless equalizer in the energy balancing system. Simulation and experimental results show good balancing performance of the lithium-ion battery pack. The fuzzy logic balancing control strategy can reduce the balancing time by 32%.

This belongs to the field of balancing technology in battery management systems, involving a high-current power battery bidirectional equalizer, including a bidirectional DC-DC converter, a relay network, and a battery management system. The battery management system monitors the battery voltage and temperature in real time and transmits the obtained temperature and voltage data to the connected microcontroller system; the microcontroller determines the single battery that needs balancing based on the voltage of the individual battery; the microcontroller system selects the relays at both ends of the single battery to be balanced, controls the input and output direction of the set bidirectional DC-DC converter, and activates the relay network to achieve balancing; the relays are respectively set at both ends of each single battery in the battery pack.

Enerkey BMS's newly launched bidirectional DC-DC intelligent equalizer is a high-current power battery bidirectional balancing method and equalizer, achieving lossless balancing of high-current power batteries; it can also meet the requirements of fast charging applications.