There are problems with thermal management of power batteries in new energy vehicles
Although the thermal management of power batteries for new energy vehicles has achieved certain development, there are still some urgent problems to be solved, such as imperfect thermal management design of single cells, unoptimized heat dissipation structure of battery system, low intelligence level of thermal management system control strategy, etc. In this regard, it is necessary to optimize the thermal design inside the battery, system heat dissipation structure and control strategy to achieve more efficient thermal management and ensure that the battery operates within the optimal temperature range.
1. Imperfect thermal management design of single cells
The design of thermal management system of power battery of new energy vehicle is crucial, but there are still some problems, especially in thermal management of single cells.
First, there is a problem of insufficient temperature uniformity in thermal management design of single cells. Since the battery pack is composed of several single cells, these single cells will generate heat during the charging and discharging process. If the heat cannot be dispersed in time and evenly, it will cause the local temperature of the battery to rise and form hot spots. This hot spot effect will not only affect the working efficiency of the battery, but also accelerate the aging of the battery and even cause safety hazards. At the same time, the complexity of the internal structure of the battery and the change of the gap between the single cells will make the heat distribution uneven. It is difficult for the current thermal management design to completely solve this problem, especially under high load or extreme environment.
Second, the matching problem of thermal response speed and thermal capacity of single cells is also a major challenge in thermal management design. The ideal thermal management system of power battery of new energy vehicle should be able to respond quickly to the changes in the heat generated by the battery and have sufficient thermal capacity to absorb or release heat energy to ensure the stability of battery temperature. However, when the power battery works 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 the existing design to find a perfect balance between lightweight and high efficiency. This may affect the cycle life and safety performance of the power battery.
2. The heat dissipation structure of the battery system needs to be optimized
There is a problem in the thermal management of the power battery 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 faces 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 the traditional heat dissipation system often cannot effectively dissipate heat in this case, resulting in too fast a temperature rise in 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.
3. Low intelligence of thermal management system control strategy
First, the control strategy has certain limitations. At present, the thermal management system of power batteries of new energy vehicles mainly adopts the traditional temperature threshold control strategy, that is, by setting static upper and lower temperature limits to trigger heat dissipation or cooling measures. However, this static control strategy cannot fully adapt to the battery thermal management needs under different working conditions and environmental conditions. For example, in a high temperature environment, the traditional temperature threshold control strategy may be too conservative, resulting in frequent triggering of heat dissipation measures, affecting the energy utilization efficiency of the battery. In a low temperature environment, the traditional control strategy may not be able to start the heating measures in time, affecting the performance and service life of the battery.
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 the thermal management system, for complex battery thermal characteristics and environmental conditions, such as battery internal temperature distribution, charging rate, ambient temperature, etc., the data processing capacity of the existing system is limited, and it is impossible to fully mine and use these data to optimize the thermal management strategy. In addition, the decision-making ability of the existing thermal management system is relatively limited, and it is impossible to perform comprehensive optimization based on multiple parameters and conditions, resulting in the accuracy and adaptability of the control strategy being limited.
