1. Current status of thermal management of power batteries for new energy vehicles

At present, with the popularity of new energy vehicles, power battery thermal management has become an important issue in this field. Power battery thermal management aims to ensure the safety, stability and performance of the battery pack, control the temperature during the battery charge and discharge cycle, and maintain the working state of the battery in extreme environments. The thermal management of power batteries in new energy vehicles mainly involves technologies such as active cooling and heating systems, heat utilization systems, battery thermal management systems, and temperature monitoring and control systems. Traditional power battery thermal management systems usually use liquid cooling or air cooling to dissipate heat through heat-conducting media to control the battery temperature. However, with the continuous innovation of technology, new thermal management technologies have been gradually introduced, such as the use of phase change materials, improvement of heat-conducting media, and structural optimization, to improve heat dissipation efficiency and reduce the temperature rise of power batteries. At the same time, intelligent temperature monitoring and control systems have also been rapidly developed, which can monitor battery temperature in real time and maintain the battery within the optimal operating temperature range by controlling the heat dissipation system or heating system. In addition, the development of heat utilization systems has also attracted much attention, aiming to effectively utilize the waste heat generated by the battery and improve the energy utilization efficiency of the entire vehicle. Although the thermal management technology of power batteries for new energy vehicles has made significant progress, it still faces some challenges. Therefore, it is necessary to conduct in-depth research on the thermal management of new energy vehicle power batteries from multiple aspects such as materials, structure, and control to better meet the development needs of new energy vehicles.

2. There are problems with thermal management of power batteries in new energy vehicles

2.1 Imperfect thermal management design of single cells

Second, the matching problem of thermal response speed and thermal capacity of single cells is also a major challenge in thermal management design. An ideal thermal management system for power batteries of new energy vehicles should be able to respond quickly to changes in the heat generated by the battery and have sufficient thermal capacity to absorb or release thermal energy to ensure the stability of the battery temperature. However, when the power battery is working in an environment with rapid charging and discharging, high-rate discharge or large temperature fluctuations, the thermal management system is often difficult to respond quickly and manage effectively. Especially when the battery design pursues high energy density, the thermal response performance and thermal capacity configuration of the thermal management system are particularly important, but it is difficult for existing designs to find a perfect balance between lightweight and high efficiency. This may affect the cycle life and safety performance of the power battery.

2.2 The heat dissipation structure of the battery system needs to be optimized

There is a problem in the thermal management of power batteries of new energy vehicles that the heat dissipation structure of the battery system needs to be optimized. At present, the heat dissipation structure of the power battery system has challenges in dealing with high temperature environments and rapid charging and discharging. It is easily damaged in high temperature environments, and excessive temperature will accelerate the aging of the battery and reduce its performance. At the same time, rapid charging and discharging will generate a lot of heat, and traditional heat dissipation systems often cannot effectively dissipate heat in this case, resulting in excessively fast temperature rise of the battery. In addition, the heat dissipation structure of the battery system is insufficient in terms of the heat dissipation effect and heat dissipation uniformity of large-capacity battery packs. With the development of new energy vehicles, the battery capacity continues to increase, and the heat dissipation problem of large-capacity battery packs has become more and more prominent. The traditional heat dissipation structure often cannot fully cover the entire battery pack, resulting in excessively high temperatures in some areas and too low temperatures in other areas, resulting in uneven heat dissipation. This uneven heat dissipation will cause the temperature difference of the single cells inside the battery pack to be too large, affecting the battery's charging and discharging performance and service life.

2.3 Low degree of intelligence of the thermal management system control strategy

Second, the degree of intelligence in data processing and decision making is limited. Although some power battery thermal management systems use sensors and control units for data monitoring and adjustment, there are still limitations in data processing and decision-making. For example, in thermal management systems, for complex battery thermal characteristics and environmental conditions, such as battery internal temperature distribution, charging rate, ambient temperature, etc., the data processing capabilities of existing systems are limited, and it is impossible to fully mine and utilize these data to optimize thermal management strategies. In addition, the decision-making capabilities of existing thermal management systems are relatively limited, and they cannot be comprehensively optimized based on multiple parameters and conditions, resulting in limited accuracy and adaptability of control strategies.