Safety issue is the main concern for current lithium-ion batteries (LIBs), especially for the high energy density cells based on nickel-rich oxide/Si-C chemistries, which could experience violent explosion and intense burning with the temperature exceeding 1000 °C during thermal runaway (TR). And moreover, within a module/system, the TR of a single cell might trigger the TR of neighboring cells, usually called TR propagation, leading to a fire accident or even a server disaster. The objective of this work is to introduce an aerogel sheet with extremely low thermal conductivity and high thermal stability to block the TR propagation. The silica aerogel sheet (SAS) is synthesized via a sol-gel process followed by supercritical fluid drying. The thermal conductivities of the obtained SAS are 0.018, 0.029, 0.043 and 0.074 W (m·K) at 20 °C, 300 °C, 500 °C and 800 °C, respectively. A simple module is constructed with two LIBs (NCM811/Si-C, 320 Wh/kg) sandwiched with a piece of SAS with various thicknesses (1.2–2.8 mm). The results show that the SAS of 1.2 mm or 1.8 mm thickness cannot stop the TR propagation. The propagation times to next cell are 50 (1.2 mm) and 106 s (1.8 mm), respectively. While the SAS of 2.3 mm or thicker can suppress the TR propagation successfully, and moreover, protect the neighboring cell from any voltage drop/collapse. The microstructure and thermal conductivity of the SAS after TR experiments do not show evident change, revealing that the as-prepared SAS is thermally stable during the violent TR process. This work provides new insights for battery thermal management system (BTMS).

中文翻译：

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使用气凝胶薄板抑制高能量密度电池（LiNi0.8Co0.1Mn0.1O2/Si-C）基模块的热失控传播


安全问题是当前锂离子电池（LIB）的主要问题，特别是基于富镍氧化物/Si-C化学物质的高能量密度电池，在温度超过1000℃时可能会发生剧烈爆炸和剧烈燃烧热失控（TR）期间。而且，在模块/系统内，单个小区的TR可能会触发相邻小区的TR，通常称为TR传播，导致火灾事故甚至服务器灾难。这项工作的目的是引入一种具有极低导热率和高热稳定性的气凝胶片来阻止 TR 传播。二氧化硅气凝胶片 (SAS) 通过溶胶凝胶工艺合成，然后进行超临界流体干燥。所得SAS在20℃、300℃、500℃和800℃下的热导率分别为0.018、0.029、0.043和0.074W(m·K)。一个简单的模块由两个 LIB（NCM811/Si-C，320Wh/kg）构成，中间夹有一块不同厚度（1.2-2.8mm）的 SAS。结果表明，1.2mm或1.8mm厚度的SAS不能阻止TR传播。到下一个单元的传播时间分别为 50 秒（1.2 毫米）和 106 秒（1.8 毫米）。而2.3mm或更厚的SAS可以成功抑制TR传播，而且可以保护相邻电池免受任何电压下降/崩溃的影响。 TR实验后SAS的微观结构和热导率没有表现出明显的变化，表明所制备的SAS在剧烈的TR过程中是热稳定的。这项工作为电池热管理系统（BTMS）提供了新的见解。