关键词: 电池热管理, 相变材料（PCM）, 风冷, 循环充放电

Abstract:

This paper specifically focuses on the notable deficiencies in heat dissipation efficiency demonstrated by the traditional battery thermal management structure that integrates Phase Change Material (PCM) with air cooling. This structure, which features a combination of "X"-shaped fins and copper columns, can significantly enhance the heat dissipation efficiency of air cooling. As a result, it meets the temperature requirements of batteries under harsh conditions.To address these issues, a novel and innovative "dissipation - storage" integrated thermal management structure, which effectively combines PCM and air cooling, is put forward. This study delves deeply into exploring the thermal characteristics of this newly proposed structure during multiple charge - discharge cycles. In these cycles, the battery discharges at a relatively high rate of 6C and charges at 2C under challenging high - temperature environmental conditions. Additionally, it meticulously investigates the influence laws of various PCM physical parameters, such as melting point, thermal conductivity, and specific heat capacity, and different cold - plate structural parameters, including thickness, shape, and fin density, on the heat transfer characteristics of the structure.The results clearly demonstrate that this new - type battery thermal management structure is highly effective. It can successfully maintain the maximum temperature of a single battery cell within a safe range of 45 °C and limit the maximum temperature difference within 3 °C throughout multiple charge - discharge cycles. The melting point of PCM proves to have a profound impact on the battery temperature rise. An excessively high melting point inevitably leads to an overly high maximum battery temperature, risking the battery's performance and lifespan. Conversely, an excessively low melting point causes PCM to melt alarmingly fast. As a result, the PCM - based cold - plate lacks the essential temperature - regulating capacity in the later part of the cycle, significantly accelerating the battery temperature rise. However, provided that PCM does not completely melt, it is evident that the lower the PCM melting point, the more conducive it is to precisely control the battery temperature within a safe range. Moreover, increasing the thickness of the PCM cold - plate, the cold - plate panel, and the fin ribs can remarkably enhance the heat dissipation performance and temperature - control stability of the structure, further improving the overall efficiency of the thermal management system.The research results provide substantial methodological support for the design of battery thermal management systems. This is of great significance for ensuring the safe use of lithium - ion batteries under long - distance continuous high - speed driving conditions and in cold regions. This research not only enriches the theoretical basis of battery thermal management but also provides practical and valuable guidance for improving the performance and safety of battery systems in specific and demanding application scenarios.

Key words: Battery thermal management, Phase Change Material (PCM), Air cooling, Charge-discharge cycle