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In recent years, with the enhancement of environmental awareness and policy support, the new energy vehicle market has developed rapidly. Among many new energy vehicles, electric vehicles have become the mainstream of development due to their zero emission and low noise characteristics. As one of the core components of electric vehicles, the performance of the battery pack directly affects important indicators such as the cruising range and safety of electric vehicles. Therefore, battery pack balancing technology has also become one of the hot spots in electric vehicle research. The main purpose of battery pack balancing technology is to balance the charge, voltage and other parameters between the individual cells in the battery pack, so as to avoid reducing the life of the entire battery pack or even causing a battery pack to have too much or too little power in one cell. safety incident. Traditional battery pack balancing technology mainly includes two methods: passive balancing and active balancing. Passive balancing achieves balancing by using a balancing circuit to discharge or charge the battery, but its balancing efficiency is low and it cannot avoid problems such as overcharge and over-discharge. Active balancing achieves balancing through targeted control of the battery, but its implementation is difficult and the control strategy is complex. In order to solve the above problems, Enerkey proposed a battery pack balancing solution based on a dynamic voltage balancing strategy. This solution analyzes the causes of voltage differences within the battery pack and designs a control algorithm that can adaptively adjust the battery pack balancing strategy during operation. This algorithm can realize the balance of the battery pack according to the dynamic voltage balancing strategy based on real-time monitoring of the voltage and power of each cell inside the battery pack, while avoiding problems such as overshoot and over-discharge. Finally, the effectiveness of the scheme was verified through experiments. Research status of battery pack balancing technology Research on battery pack balancing technology began in the 1980s. With the rise of new energy vehicles, it has received more and more attention. Battery pack balancing technology aims to maintain the charge balance between individual cells in the battery pack and avoid battery capacity decline and shortened life due to uneven charging. At present, research on battery pack balancing technology has achieved many results, mainly including the following aspects.   1. Traditional balancing technology Traditional battery pack balancing technology mainly uses components such as resistors, relays and thyristors for balancing. The principle is to discharge the single cells with high voltage in the battery pack through resistors, relays and other components to achieve the same voltage as the battery pack. Low single cell balancing purpose. Traditional balancing technology has the advantages of simplicity, reliability, and low cost, but it has shortcomings such as low balancing efficiency and large energy waste.   2. Intelligent balancing technology Intelligent balancing technology is the focus of research on battery pack balancing technology in recent years. It uses advanced electronic technology and algorithms to accurately control and manage each single cell in the battery pack. Intelligent balancing technology is mainly divided into two methods: passive balancing and active balancing. Passive balancing mainly achieves the purpose of balancing the battery pack by adjusting the parameters during the charging and discharging process of the battery pack. Active balancing adds components such as control circuits and sensors to the battery pack to monitor and control the status of each single cell in real time, thereby achieving the purpose of balancing the battery pack. Intelligent balancing technology has the advantages of high balancing efficiency, high energy utilization, and good safety.   3. Energy management technology Energy management technology refers to the optimal management and scheduling of battery packs based on battery pack balancing technology and comprehensively considering factors such as battery pack performance characteristics, vehicle operating conditions, and energy demand. Energy management technology includes energy prediction, battery capacity estimation, battery health status diagnosis, etc. Through precise management and control of the battery pack, the life of the battery pack can be extended, energy utilization and safety improved. Design and optimization of new electric vehicle battery pack balancing system The design and optimization of the new electric vehicle battery pack balancing system aims to improve the efficiency and energy utilization of battery pack balancing while ensuring the safety of electric vehicles. The design and optimization of the new electric vehicle battery pack balancing system mainly includes the following aspects.   1. Design of balancing circuit The battery pack balancing circuit is the core component of the electric vehicle battery pack balancing system. The key to its design lies in balancing efficiency, energy utilization and safety. The design of the battery pack balancing circuit needs to comprehensively consider the characteristics and working conditions of the battery pack, and adopt appropriate balancing solutions and balancing strategies. The following aspects need to be considered during the design process: Selection of balancing strategy: Both traditional balancing technology and intelligent balancing technology have their advantages and disadvantages, and the appropriate balancing strategy should be selected according to the specific situation. The structure of the balancing circuit: The structural design of the balancing circuit needs to meet the requirements of high balancing efficiency, high energy utilization, safety and reliability of the battery pack. Commonly used balancing circuit structures include resistor voltage dividing balancing, switch balancing, AC balancing, etc. Control of the balancing circuit: The control of the balancing circuit requires real-time monitoring of parameters such as voltage and temperature of each single cell in the battery pack, and control and adjustment according to the set balancing strategy. 2. Design of energy management system The energy management system is another important component of the battery pack balancing system of electric vehicles. It is designed to optimize the energy utilization of the battery pack, extend the life of the battery pack, and ensure the safety of electric vehicles. The design of the energy management system needs to comprehensively consider the following aspects: Selection of energy management strategies: Energy management strategies include charging strategies, discharging strategies, and load control strategies. Different energy management strategies have different impacts on the life and energy utilization of the battery pack. Control of the energy management system: The control of the energy management system requires real-time monitoring of the status and energy changes of each single cell in the battery pack, and control and adjustment according to the set energy management strategy. Optimization of energy management system: Through careful management and scheduling of battery packs, the energy utilization and life of the battery pack can be optimized, and the performance and safety of electric vehicles can be improved. 3. Design of battery pack safety protection system The battery pack safety protection system is another important component of the electric vehicle battery pack balancing system, which is designed to ensure the safety of electric vehicles. The battery pack safety protection system mainly includes overcharge protection, over-discharge protection, short-circuit protection, over-temperature protection and other functions. Through real-time monitoring and protection of the battery pack, dangerous accidents in the battery pack can be avoided. Theoretical research on battery pack balancing system design 1. Analysis of causes of voltage differences within the battery pack The internal voltage difference of the battery pack is mainly due to the differences in internal resistance, electrochemical reaction rate and other factors between individual cells. In actual operation, due to the different service life and number of charge and discharge cycles of different cells, the internal resistance of the cells is different, which in turn causes differences in the internal voltage of the battery pack. In addition, due to the self-discharge phenomenon of the battery, long-term placement will cause the battery's power to decrease, resulting in voltage differences within the battery pack. 2. Dynamic voltage balancing strategy The dynamic voltage balancing strategy is a control strategy that can adaptively adjust the battery pack balancing strategy during operation. This strategy dynamically adjusts the working status of the balancing circuit according to the voltage and power of each cell inside the battery pack to achieve balance of the battery pack and avoid problems such as overshoot and over-discharge. In terms of specific implementation, we divide the battery pack balancing system into two parts: the balancing controller and the balancing circuit. The balancing controller monitors the voltage and power of each cell inside the battery pack in real time, calculates the working status of the balancing circuit based on the dynamic voltage balancing strategy, and then controls the switching status of the balancing circuit to achieve balancing of the battery pack. 3.Control algorithm The core of the dynamic voltage balancing strategy is the control algorithm. We designed a battery pack balancing controller based on PID control algorithm. This controller can balance the voltage and power of each cell within the battery pack when the voltage difference within the battery pack is small, preventing overshoot, over-discharge and other problems from occurring. The input parameters of the controller include the voltage and power of each cell inside the battery pack. Through real-time monitoring and analysis of these parameters, the working status of the balancing circuit can be calculated, thereby achieving the balancing of the battery pack. In terms of specific implementation, we adopted the PID control algorithm and added feedback mechanism and fuzzy control to ensure control accuracy and control effect. Among them, the feedback mechanism can dynamically adjust the parameters of the control algorithm according to the output state of the equalization controller, thereby achieving more precise equalization control. In addition, we have designed different control algorithms for different types of battery packs. For example, the control algorithm for a lithium battery pack needs to consider factors such as the chemical reaction rate inside the battery pack, as well as the charge and discharge characteristics of the lithium battery, so as to formulate corresponding balancing strategies and control algorithms. Experimental verification In order to verify the effectiveness of the proposed battery pack balancing system, we conducted a series of experiments. First, we tested different types of battery packs, including lead-acid, nickel-metal hydride, and lithium. Through statistics and analysis of experimental data, we found that the proposed dynamic voltage balancing strategy and control algorithm can effectively achieve the balance of the battery pack and avoid overshoot, over-discharge and other problems. Second, we conducted long-running experiments. In the experiment, we placed the battery pack in different environments, simulated different usage scenarios, and then monitored the performance of the battery pack. Through statistics and analysis of experimental data, we found that the proposed battery pack balancing system has high reliability and stability and can meet the needs of use in different scenarios. Finally, we also conducted practical application experiments. We applied the proposed battery pack balancing system to a new electric vehicle and conducted a road test drive. Through the analysis of test drive data, we found that the performance of electric vehicles has been significantly improved, including cruising range, acceleration performance and other aspects. With the rapid development of electric vehicles, the research and optimization of battery pack balancing systems have received increasing attention. Focusing on the research on the battery pack balancing system of electric vehicles, we conducted an in-depth discussion on the battery pack balancing technology, energy management system and battery pack safety protection system. By analyzing the development status and existing problems of battery pack balancing technology, an optimization plan for intelligent balancing technology is proposed, and the design method of balancing circuit structure and control is discussed. In general, the electric vehicle battery pack balancing system is an important part of the development of electric vehicle technology, and its optimization and improvement are crucial to the performance and safety of electric vehicles.