浅谈CMD在动力电池包上的被动安全功能

Brief Talk About Passive Safety Function of CMD on Power Battery Pack

提出一种带有凝露控制系统(CMD,Condensation Measurement Device)、压力平衡、防爆及快速泄压功能的组件,应用于新能源车动力电池包。大部分电池包使用透气膜组件来解决压力平衡问题,透气膜片能够阻挡液态水的侵入,但是无法阻隔空气中的水分子进入到电池包内,因此无法帮助控制电池包内部的空气湿度。电池包热管理系统中液冷是目前的主流技术,并且随着电池包能量密度的提升和快速充电的技术要求,液冷板的使用量成倍增加。若电池包内空气湿度过大时冷却系统启动,冷却板外壁和裸露金属导体表面以及pack内表面极易产生冷凝水。电池包内冷凝水无法排出所致的长期潮湿环境,可能造成电池包内温度传感器的零点漂移以及零件腐蚀老化和绝缘下降造成短路或高压系统拉弧,影响动力电池包的供电可靠性,严重时可能引起电池包安全故障,因此解决电池包冷却系统诱发冷凝水的问题十分重要。

A component with not only condensation control system( abbreviation: CMD, full name:Condensation Measurement Device), but also pressure balance, explosion-proof and rapid pressure relief function is proposed for use in new energy vehicle power battery packs( hereinafter referred to as “ battery packs”). Most battery packs use ventilationmembrane components to solve the pressure balance problem. The ventilation membrane used here can block the intrusion liquid water, but cannot prevent water molecules in the air from entering the battery pack, and cannot help control the internal air humidity of the battery pack. Liquid cooling is the current mainstream technology in the battery pack thermal management system, and with the improvement of battery pack energy density and the technical requirements for fast charging, the usage of liquid cooling plates has doubled. If the cooling system is activated when the air humidity in the battery pack is too high, the outer wall of the cooling plate, the exposed metal conductor surface and the inner surface of the pack can easily generate condensation water.The long-term humid environment caused by the inability to discharge the condensed water in the battery pack may cause the zero-point drift of the temperature sensor in the battery pack and the corrosion and aging of the internal parts of the battery pack, even the decrease of the insulation in the battery pack, which may result in short circuit or arcing of the high-voltage system, which affects the power supply reliability of the battery pack, in severe cases,it may cause battery pack safety failures.Therefore, it is very important to solve the problem of condensed water induced by the battery pack cooling system.